[e90b2f]: src / gc-unstable / os_dep.c Maximize Restore History

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os_dep.c    4698 lines (4211 with data), 166.0 kB

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/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved.
* Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
* Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
#include "private/gc_priv.h"
#if defined(LINUX) && !defined(POWERPC)
# include <linux/version.h>
# if (LINUX_VERSION_CODE <= 0x10400)
/* Ugly hack to get struct sigcontext_struct definition. Required */
/* for some early 1.3.X releases. Will hopefully go away soon. */
/* in some later Linux releases, asm/sigcontext.h may have to */
/* be included instead. */
# define __KERNEL__
# include <asm/signal.h>
# undef __KERNEL__
# else
/* Kernels prior to 2.1.1 defined struct sigcontext_struct instead of */
/* struct sigcontext. libc6 (glibc2) uses "struct sigcontext" in */
/* prototypes, so we have to include the top-level sigcontext.h to */
/* make sure the former gets defined to be the latter if appropriate. */
# include <features.h>
# if 2 <= __GLIBC__
# if 2 == __GLIBC__ && 0 == __GLIBC_MINOR__
/* glibc 2.1 no longer has sigcontext.h. But signal.h */
/* has the right declaration for glibc 2.1. */
# include <sigcontext.h>
# endif /* 0 == __GLIBC_MINOR__ */
# else /* not 2 <= __GLIBC__ */
/* libc5 doesn't have <sigcontext.h>: go directly with the kernel */
/* one. Check LINUX_VERSION_CODE to see which we should reference. */
# include <asm/sigcontext.h>
# endif /* 2 <= __GLIBC__ */
# endif
#endif
#if !defined(OS2) && !defined(PCR) && !defined(AMIGA) && !defined(MACOS) \
&& !defined(MSWINCE) && !defined(__CC_ARM)
# include <sys/types.h>
# if !defined(MSWIN32)
# include <unistd.h>
# endif
#endif
#include <stdio.h>
#if defined(MSWINCE) || defined(SN_TARGET_PS3)
# define SIGSEGV 0 /* value is irrelevant */
#else
# include <signal.h>
#endif
#if defined(UNIX_LIKE) || defined(CYGWIN32) || defined(NACL)
# include <fcntl.h>
#endif
#if defined(LINUX) || defined(LINUX_STACKBOTTOM)
# include <ctype.h>
#endif
/* Blatantly OS dependent routines, except for those that are related */
/* to dynamic loading. */
#ifdef AMIGA
# define GC_AMIGA_DEF
# include "extra/AmigaOS.c"
# undef GC_AMIGA_DEF
#endif
#if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32)
# ifndef WIN32_LEAN_AND_MEAN
# define WIN32_LEAN_AND_MEAN 1
# endif
# define NOSERVICE
# include <windows.h>
/* It's not clear this is completely kosher under Cygwin. But it */
/* allows us to get a working GC_get_stack_base. */
#endif
#ifdef MACOS
# include <Processes.h>
#endif
#ifdef IRIX5
# include <sys/uio.h>
# include <malloc.h> /* for locking */
#endif
#if defined(LINUX) || defined(FREEBSD) || defined(SOLARIS) || defined(IRIX5) \
|| ((defined(USE_MMAP) || defined(USE_MUNMAP)) \
&& !defined(MSWIN32) && !defined(MSWINCE))
# define MMAP_SUPPORTED
#endif
#if defined(MMAP_SUPPORTED) || defined(ADD_HEAP_GUARD_PAGES)
# if defined(USE_MUNMAP) && !defined(USE_MMAP)
# error "invalid config - USE_MUNMAP requires USE_MMAP"
# endif
# include <sys/types.h>
# include <sys/mman.h>
# include <sys/stat.h>
# include <errno.h>
#endif
#ifdef DARWIN
/* for get_etext and friends */
# include <mach-o/getsect.h>
#endif
#ifdef DJGPP
/* Apparently necessary for djgpp 2.01. May cause problems with */
/* other versions. */
typedef long unsigned int caddr_t;
#endif
#ifdef PCR
# include "il/PCR_IL.h"
# include "th/PCR_ThCtl.h"
# include "mm/PCR_MM.h"
#endif
#if !defined(NO_EXECUTE_PERMISSION)
STATIC GC_bool GC_pages_executable = TRUE;
#else
STATIC GC_bool GC_pages_executable = FALSE;
#endif
#define IGNORE_PAGES_EXECUTABLE 1
/* Undefined on GC_pages_executable real use. */
#ifdef NEED_PROC_MAPS
/* We need to parse /proc/self/maps, either to find dynamic libraries, */
/* and/or to find the register backing store base (IA64). Do it once */
/* here. */
#define READ read
/* Repeatedly perform a read call until the buffer is filled or */
/* we encounter EOF. */
STATIC ssize_t GC_repeat_read(int fd, char *buf, size_t count)
{
ssize_t num_read = 0;
ssize_t result;
ASSERT_CANCEL_DISABLED();
while (num_read < count) {
result = READ(fd, buf + num_read, count - num_read);
if (result < 0) return result;
if (result == 0) break;
num_read += result;
}
return num_read;
}
#ifdef THREADS
/* Determine the length of a file by incrementally reading it into a */
/* This would be silly to use on a file supporting lseek, but Linux */
/* /proc files usually do not. */
STATIC size_t GC_get_file_len(int f)
{
size_t total = 0;
ssize_t result;
# define GET_FILE_LEN_BUF_SZ 500
char buf[GET_FILE_LEN_BUF_SZ];
do {
result = read(f, buf, GET_FILE_LEN_BUF_SZ);
if (result == -1) return 0;
total += result;
} while (result > 0);
return total;
}
STATIC size_t GC_get_maps_len(void)
{
int f = open("/proc/self/maps", O_RDONLY);
size_t result;
if (f < 0) return 0; /* treat missing file as empty */
result = GC_get_file_len(f);
close(f);
return result;
}
#endif /* THREADS */
/* Copy the contents of /proc/self/maps to a buffer in our address */
/* space. Return the address of the buffer, or zero on failure. */
/* This code could be simplified if we could determine its size ahead */
/* of time. */
GC_INNER char * GC_get_maps(void)
{
int f;
int result;
static char init_buf[1];
static char *maps_buf = init_buf;
static size_t maps_buf_sz = 1;
size_t maps_size, old_maps_size = 0;
/* The buffer is essentially static, so there must be a single client. */
GC_ASSERT(I_HOLD_LOCK());
/* Note that in the presence of threads, the maps file can */
/* essentially shrink asynchronously and unexpectedly as */
/* threads that we already think of as dead release their */
/* stacks. And there is no easy way to read the entire */
/* file atomically. This is arguably a misfeature of the */
/* /proc/.../maps interface. */
/* Since we don't believe the file can grow */
/* asynchronously, it should suffice to first determine */
/* the size (using lseek or read), and then to reread the */
/* file. If the size is inconsistent we have to retry. */
/* This only matters with threads enabled, and if we use */
/* this to locate roots (not the default). */
# ifdef THREADS
/* Determine the initial size of /proc/self/maps. */
/* Note that lseek doesn't work, at least as of 2.6.15. */
maps_size = GC_get_maps_len();
if (0 == maps_size) return 0;
# else
maps_size = 4000; /* Guess */
# endif
/* Read /proc/self/maps, growing maps_buf as necessary. */
/* Note that we may not allocate conventionally, and */
/* thus can't use stdio. */
do {
while (maps_size >= maps_buf_sz) {
/* Grow only by powers of 2, since we leak "too small" buffers.*/
while (maps_size >= maps_buf_sz) maps_buf_sz *= 2;
maps_buf = GC_scratch_alloc(maps_buf_sz);
# ifdef THREADS
/* Recompute initial length, since we allocated. */
/* This can only happen a few times per program */
/* execution. */
maps_size = GC_get_maps_len();
if (0 == maps_size) return 0;
# endif
if (maps_buf == 0) return 0;
}
GC_ASSERT(maps_buf_sz >= maps_size + 1);
f = open("/proc/self/maps", O_RDONLY);
if (-1 == f) return 0;
# ifdef THREADS
old_maps_size = maps_size;
# endif
maps_size = 0;
do {
result = GC_repeat_read(f, maps_buf, maps_buf_sz-1);
if (result <= 0)
break;
maps_size += result;
} while (result == maps_buf_sz-1);
close(f);
if (result <= 0)
return 0;
# ifdef THREADS
if (maps_size > old_maps_size) {
if (GC_print_stats)
GC_log_printf(
"Unexpected maps size growth from %lu to %lu\n",
(unsigned long)old_maps_size,
(unsigned long)maps_size);
ABORT("Unexpected asynchronous /proc/self/maps growth: "
"unregistered thread?");
}
# endif
} while (maps_size >= maps_buf_sz || maps_size < old_maps_size);
/* In the single-threaded case, the second clause is false. */
maps_buf[maps_size] = '\0';
/* Apply fn to result. */
return maps_buf;
}
/*
* GC_parse_map_entry parses an entry from /proc/self/maps so we can
* locate all writable data segments that belong to shared libraries.
* The format of one of these entries and the fields we care about
* is as follows:
* XXXXXXXX-XXXXXXXX r-xp 00000000 30:05 260537 name of mapping...\n
* ^^^^^^^^ ^^^^^^^^ ^^^^ ^^
* start end prot maj_dev
*
* Note that since about august 2003 kernels, the columns no longer have
* fixed offsets on 64-bit kernels. Hence we no longer rely on fixed offsets
* anywhere, which is safer anyway.
*/
/* Assign various fields of the first line in buf_ptr to (*start), */
/* (*end), (*prot), (*maj_dev) and (*mapping_name). mapping_name may */
/* be NULL. (*prot) and (*mapping_name) are assigned pointers into the */
/* original buffer. */
GC_INNER char *GC_parse_map_entry(char *buf_ptr, ptr_t *start, ptr_t *end,
char **prot, unsigned int *maj_dev,
char **mapping_name)
{
char *start_start, *end_start, *maj_dev_start;
char *p;
char *endp;
if (buf_ptr == NULL || *buf_ptr == '\0') {
return NULL;
}
p = buf_ptr;
while (isspace(*p)) ++p;
start_start = p;
GC_ASSERT(isxdigit(*start_start));
*start = (ptr_t)strtoul(start_start, &endp, 16); p = endp;
GC_ASSERT(*p=='-');
++p;
end_start = p;
GC_ASSERT(isxdigit(*end_start));
*end = (ptr_t)strtoul(end_start, &endp, 16); p = endp;
GC_ASSERT(isspace(*p));
while (isspace(*p)) ++p;
GC_ASSERT(*p == 'r' || *p == '-');
*prot = p;
/* Skip past protection field to offset field */
while (!isspace(*p)) ++p; while (isspace(*p)) ++p;
GC_ASSERT(isxdigit(*p));
/* Skip past offset field, which we ignore */
while (!isspace(*p)) ++p; while (isspace(*p)) ++p;
maj_dev_start = p;
GC_ASSERT(isxdigit(*maj_dev_start));
*maj_dev = strtoul(maj_dev_start, NULL, 16);
if (mapping_name == 0) {
while (*p && *p++ != '\n');
} else {
while (*p && *p != '\n' && *p != '/' && *p != '[') p++;
*mapping_name = p;
while (*p && *p++ != '\n');
}
return p;
}
#if defined(IA64) || defined(INCLUDE_LINUX_THREAD_DESCR)
/* Try to read the backing store base from /proc/self/maps. */
/* Return the bounds of the writable mapping with a 0 major device, */
/* which includes the address passed as data. */
/* Return FALSE if there is no such mapping. */
GC_INNER GC_bool GC_enclosing_mapping(ptr_t addr, ptr_t *startp,
ptr_t *endp)
{
char *prot;
ptr_t my_start, my_end;
unsigned int maj_dev;
char *maps = GC_get_maps();
char *buf_ptr = maps;
if (0 == maps) return(FALSE);
for (;;) {
buf_ptr = GC_parse_map_entry(buf_ptr, &my_start, &my_end,
&prot, &maj_dev, 0);
if (buf_ptr == NULL) return FALSE;
if (prot[1] == 'w' && maj_dev == 0) {
if (my_end > addr && my_start <= addr) {
*startp = my_start;
*endp = my_end;
return TRUE;
}
}
}
return FALSE;
}
#endif /* IA64 || INCLUDE_LINUX_THREAD_DESCR */
#if defined(REDIRECT_MALLOC)
/* Find the text(code) mapping for the library whose name, after */
/* stripping the directory part, starts with nm. */
GC_INNER GC_bool GC_text_mapping(char *nm, ptr_t *startp, ptr_t *endp)
{
size_t nm_len = strlen(nm);
char *prot;
char *map_path;
ptr_t my_start, my_end;
unsigned int maj_dev;
char *maps = GC_get_maps();
char *buf_ptr = maps;
if (0 == maps) return(FALSE);
for (;;) {
buf_ptr = GC_parse_map_entry(buf_ptr, &my_start, &my_end,
&prot, &maj_dev, &map_path);
if (buf_ptr == NULL) return FALSE;
if (prot[0] == 'r' && prot[1] == '-' && prot[2] == 'x') {
char *p = map_path;
/* Set p to point just past last slash, if any. */
while (*p != '\0' && *p != '\n' && *p != ' ' && *p != '\t') ++p;
while (*p != '/' && p >= map_path) --p;
++p;
if (strncmp(nm, p, nm_len) == 0) {
*startp = my_start;
*endp = my_end;
return TRUE;
}
}
}
return FALSE;
}
#endif /* REDIRECT_MALLOC */
#ifdef IA64
static ptr_t backing_store_base_from_proc(void)
{
ptr_t my_start, my_end;
if (!GC_enclosing_mapping(GC_save_regs_in_stack(), &my_start, &my_end)) {
if (GC_print_stats) {
GC_log_printf("Failed to find backing store base from /proc\n");
}
return 0;
}
return my_start;
}
#endif
#endif /* NEED_PROC_MAPS */
#if defined(SEARCH_FOR_DATA_START)
/* The I386 case can be handled without a search. The Alpha case */
/* used to be handled differently as well, but the rules changed */
/* for recent Linux versions. This seems to be the easiest way to */
/* cover all versions. */
# if defined(LINUX) || defined(HURD)
/* Some Linux distributions arrange to define __data_start. Some */
/* define data_start as a weak symbol. The latter is technically */
/* broken, since the user program may define data_start, in which */
/* case we lose. Nonetheless, we try both, preferring __data_start.*/
/* We assume gcc-compatible pragmas. */
# pragma weak __data_start
extern int __data_start[];
# pragma weak data_start
extern int data_start[];
# endif /* LINUX */
extern int _end[];
ptr_t GC_data_start = NULL;
ptr_t GC_find_limit(ptr_t, GC_bool);
GC_INNER void GC_init_linux_data_start(void)
{
# if defined(LINUX) || defined(HURD)
/* Try the easy approaches first: */
if ((ptr_t)__data_start != 0) {
GC_data_start = (ptr_t)(__data_start);
return;
}
if ((ptr_t)data_start != 0) {
GC_data_start = (ptr_t)(data_start);
return;
}
# endif /* LINUX */
GC_data_start = GC_find_limit((ptr_t)(_end), FALSE);
}
#endif /* SEARCH_FOR_DATA_START */
#ifdef ECOS
# ifndef ECOS_GC_MEMORY_SIZE
# define ECOS_GC_MEMORY_SIZE (448 * 1024)
# endif /* ECOS_GC_MEMORY_SIZE */
/* FIXME: This is a simple way of allocating memory which is */
/* compatible with ECOS early releases. Later releases use a more */
/* sophisticated means of allocating memory than this simple static */
/* allocator, but this method is at least bound to work. */
static char ecos_gc_memory[ECOS_GC_MEMORY_SIZE];
static char *ecos_gc_brk = ecos_gc_memory;
static void *tiny_sbrk(ptrdiff_t increment)
{
void *p = ecos_gc_brk;
ecos_gc_brk += increment;
if (ecos_gc_brk > ecos_gc_memory + sizeof(ecos_gc_memory)) {
ecos_gc_brk -= increment;
return NULL;
}
return p;
}
# define sbrk tiny_sbrk
#endif /* ECOS */
#if defined(NETBSD) && defined(__ELF__)
ptr_t GC_data_start = NULL;
ptr_t GC_find_limit(ptr_t, GC_bool);
extern char **environ;
GC_INNER void GC_init_netbsd_elf(void)
{
/* This may need to be environ, without the underscore, for */
/* some versions. */
GC_data_start = GC_find_limit((ptr_t)&environ, FALSE);
}
#endif /* NETBSD */
#ifdef OPENBSD
static struct sigaction old_segv_act;
STATIC sigjmp_buf GC_jmp_buf_openbsd;
# ifdef THREADS
# include <sys/syscall.h>
extern sigset_t __syscall(quad_t, ...);
# endif
/* Don't use GC_find_limit() because siglongjmp() outside of the */
/* signal handler by-passes our userland pthreads lib, leaving */
/* SIGSEGV and SIGPROF masked. Instead, use this custom one that */
/* works-around the issues. */
/*ARGSUSED*/
STATIC void GC_fault_handler_openbsd(int sig)
{
siglongjmp(GC_jmp_buf_openbsd, 1);
}
/* Return the first non-addressible location > p or bound. */
/* Requires the allocation lock. */
STATIC ptr_t GC_find_limit_openbsd(ptr_t p, ptr_t bound)
{
static volatile ptr_t result;
/* Safer if static, since otherwise it may not be */
/* preserved across the longjmp. Can safely be */
/* static since it's only called with the */
/* allocation lock held. */
struct sigaction act;
size_t pgsz = (size_t)sysconf(_SC_PAGESIZE);
GC_ASSERT(I_HOLD_LOCK());
act.sa_handler = GC_fault_handler_openbsd;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_NODEFER | SA_RESTART;
sigaction(SIGSEGV, &act, &old_segv_act);
if (sigsetjmp(GC_jmp_buf_openbsd, 1) == 0) {
result = (ptr_t)((word)p & ~(pgsz-1));
for (;;) {
result += pgsz;
if (result >= bound) {
result = bound;
break;
}
GC_noop1((word)(*result));
}
}
# ifdef THREADS
/* Due to the siglongjump we need to manually unmask SIGPROF. */
__syscall(SYS_sigprocmask, SIG_UNBLOCK, sigmask(SIGPROF));
# endif
sigaction(SIGSEGV, &old_segv_act, 0);
return(result);
}
/* Return first addressable location > p or bound. */
/* Requires the allocation lock. */
STATIC ptr_t GC_skip_hole_openbsd(ptr_t p, ptr_t bound)
{
static volatile ptr_t result;
static volatile int firstpass;
struct sigaction act;
size_t pgsz = (size_t)sysconf(_SC_PAGESIZE);
GC_ASSERT(I_HOLD_LOCK());
act.sa_handler = GC_fault_handler_openbsd;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_NODEFER | SA_RESTART;
sigaction(SIGSEGV, &act, &old_segv_act);
firstpass = 1;
result = (ptr_t)((word)p & ~(pgsz-1));
if (sigsetjmp(GC_jmp_buf_openbsd, 1) != 0 || firstpass) {
firstpass = 0;
result += pgsz;
if (result >= bound) {
result = bound;
} else {
GC_noop1((word)(*result));
}
}
sigaction(SIGSEGV, &old_segv_act, 0);
return(result);
}
#endif /* OPENBSD */
# ifdef OS2
# include <stddef.h>
# if !defined(__IBMC__) && !defined(__WATCOMC__) /* e.g. EMX */
struct exe_hdr {
unsigned short magic_number;
unsigned short padding[29];
long new_exe_offset;
};
#define E_MAGIC(x) (x).magic_number
#define EMAGIC 0x5A4D
#define E_LFANEW(x) (x).new_exe_offset
struct e32_exe {
unsigned char magic_number[2];
unsigned char byte_order;
unsigned char word_order;
unsigned long exe_format_level;
unsigned short cpu;
unsigned short os;
unsigned long padding1[13];
unsigned long object_table_offset;
unsigned long object_count;
unsigned long padding2[31];
};
#define E32_MAGIC1(x) (x).magic_number[0]
#define E32MAGIC1 'L'
#define E32_MAGIC2(x) (x).magic_number[1]
#define E32MAGIC2 'X'
#define E32_BORDER(x) (x).byte_order
#define E32LEBO 0
#define E32_WORDER(x) (x).word_order
#define E32LEWO 0
#define E32_CPU(x) (x).cpu
#define E32CPU286 1
#define E32_OBJTAB(x) (x).object_table_offset
#define E32_OBJCNT(x) (x).object_count
struct o32_obj {
unsigned long size;
unsigned long base;
unsigned long flags;
unsigned long pagemap;
unsigned long mapsize;
unsigned long reserved;
};
#define O32_FLAGS(x) (x).flags
#define OBJREAD 0x0001L
#define OBJWRITE 0x0002L
#define OBJINVALID 0x0080L
#define O32_SIZE(x) (x).size
#define O32_BASE(x) (x).base
# else /* IBM's compiler */
/* A kludge to get around what appears to be a header file bug */
# ifndef WORD
# define WORD unsigned short
# endif
# ifndef DWORD
# define DWORD unsigned long
# endif
# define EXE386 1
# include <newexe.h>
# include <exe386.h>
# endif /* __IBMC__ */
# define INCL_DOSEXCEPTIONS
# define INCL_DOSPROCESS
# define INCL_DOSERRORS
# define INCL_DOSMODULEMGR
# define INCL_DOSMEMMGR
# include <os2.h>
# endif /* OS/2 */
/* Find the page size */
GC_INNER word GC_page_size = 0;
#if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32)
# ifndef VER_PLATFORM_WIN32_CE
# define VER_PLATFORM_WIN32_CE 3
# endif
# if defined(MSWINCE) && defined(THREADS)
GC_INNER GC_bool GC_dont_query_stack_min = FALSE;
# endif
GC_INNER void GC_setpagesize(void)
{
GetSystemInfo(&GC_sysinfo);
GC_page_size = GC_sysinfo.dwPageSize;
# if defined(MSWINCE) && !defined(_WIN32_WCE_EMULATION)
{
OSVERSIONINFO verInfo;
/* Check the current WinCE version. */
verInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
if (!GetVersionEx(&verInfo))
ABORT("GetVersionEx failed");
if (verInfo.dwPlatformId == VER_PLATFORM_WIN32_CE &&
verInfo.dwMajorVersion < 6) {
/* Only the first 32 MB of address space belongs to the */
/* current process (unless WinCE 6.0+ or emulation). */
GC_sysinfo.lpMaximumApplicationAddress = (LPVOID)((word)32 << 20);
# ifdef THREADS
/* On some old WinCE versions, it's observed that */
/* VirtualQuery calls don't work properly when used to */
/* get thread current stack committed minimum. */
if (verInfo.dwMajorVersion < 5)
GC_dont_query_stack_min = TRUE;
# endif
}
}
# endif
}
# ifndef CYGWIN32
# define is_writable(prot) ((prot) == PAGE_READWRITE \
|| (prot) == PAGE_WRITECOPY \
|| (prot) == PAGE_EXECUTE_READWRITE \
|| (prot) == PAGE_EXECUTE_WRITECOPY)
/* Return the number of bytes that are writable starting at p. */
/* The pointer p is assumed to be page aligned. */
/* If base is not 0, *base becomes the beginning of the */
/* allocation region containing p. */
STATIC word GC_get_writable_length(ptr_t p, ptr_t *base)
{
MEMORY_BASIC_INFORMATION buf;
word result;
word protect;
result = VirtualQuery(p, &buf, sizeof(buf));
if (result != sizeof(buf)) ABORT("Weird VirtualQuery result");
if (base != 0) *base = (ptr_t)(buf.AllocationBase);
protect = (buf.Protect & ~(PAGE_GUARD | PAGE_NOCACHE));
if (!is_writable(protect)) {
return(0);
}
if (buf.State != MEM_COMMIT) return(0);
return(buf.RegionSize);
}
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
int dummy;
ptr_t sp = (ptr_t)(&dummy);
ptr_t trunc_sp = (ptr_t)((word)sp & ~(GC_page_size - 1));
/* FIXME: This won't work if called from a deeply recursive */
/* client code (and the committed stack space has grown). */
word size = GC_get_writable_length(trunc_sp, 0);
GC_ASSERT(size != 0);
sb -> mem_base = trunc_sp + size;
return GC_SUCCESS;
}
# else /* CYGWIN32 */
/* An alternate version for Cygwin (adapted from Dave Korn's */
/* gcc version of boehm-gc). */
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
extern void * _tlsbase __asm__ ("%fs:4");
sb -> mem_base = _tlsbase;
return GC_SUCCESS;
}
# endif /* CYGWIN32 */
# define HAVE_GET_STACK_BASE
#else /* !MSWIN32 */
GC_INNER void GC_setpagesize(void)
{
# if defined(MPROTECT_VDB) || defined(PROC_VDB) || defined(USE_MMAP)
GC_page_size = GETPAGESIZE();
if (!GC_page_size) ABORT("getpagesize() failed");
# else
/* It's acceptable to fake it. */
GC_page_size = HBLKSIZE;
# endif
}
#endif /* !MSWIN32 */
#ifdef BEOS
# include <kernel/OS.h>
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
thread_info th;
get_thread_info(find_thread(NULL),&th);
sb->mem_base = th.stack_end;
return GC_SUCCESS;
}
# define HAVE_GET_STACK_BASE
#endif /* BEOS */
#ifdef OS2
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
PTIB ptib; /* thread information block */
PPIB ppib;
if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) {
ABORT("DosGetInfoBlocks failed");
}
sb->mem_base = ptib->tib_pstacklimit;
return GC_SUCCESS;
}
# define HAVE_GET_STACK_BASE
#endif /* OS2 */
# ifdef AMIGA
# define GC_AMIGA_SB
# include "extra/AmigaOS.c"
# undef GC_AMIGA_SB
# endif /* AMIGA */
# if defined(NEED_FIND_LIMIT) || defined(UNIX_LIKE)
typedef void (*GC_fault_handler_t)(int);
# if defined(SUNOS5SIGS) || defined(IRIX5) || defined(OSF1) \
|| defined(HURD) || defined(NETBSD)
static struct sigaction old_segv_act;
# if defined(_sigargs) /* !Irix6.x */ || defined(HPUX) \
|| defined(HURD) || defined(NETBSD) || defined(FREEBSD)
static struct sigaction old_bus_act;
# endif
# else
static GC_fault_handler_t old_segv_handler, old_bus_handler;
# endif
GC_INNER void GC_set_and_save_fault_handler(GC_fault_handler_t h)
{
# if defined(SUNOS5SIGS) || defined(IRIX5) \
|| defined(OSF1) || defined(HURD) || defined(NETBSD)
struct sigaction act;
act.sa_handler = h;
# ifdef SIGACTION_FLAGS_NODEFER_HACK
/* Was necessary for Solaris 2.3 and very temporary */
/* NetBSD bugs. */
act.sa_flags = SA_RESTART | SA_NODEFER;
# else
act.sa_flags = SA_RESTART;
# endif
(void) sigemptyset(&act.sa_mask);
# ifdef GC_IRIX_THREADS
/* Older versions have a bug related to retrieving and */
/* and setting a handler at the same time. */
(void) sigaction(SIGSEGV, 0, &old_segv_act);
(void) sigaction(SIGSEGV, &act, 0);
# else
(void) sigaction(SIGSEGV, &act, &old_segv_act);
# if defined(IRIX5) && defined(_sigargs) /* Irix 5.x, not 6.x */ \
|| defined(HPUX) || defined(HURD) || defined(NETBSD) \
|| defined(FREEBSD)
/* Under Irix 5.x or HP/UX, we may get SIGBUS. */
/* Pthreads doesn't exist under Irix 5.x, so we */
/* don't have to worry in the threads case. */
(void) sigaction(SIGBUS, &act, &old_bus_act);
# endif
# endif /* GC_IRIX_THREADS */
# else
old_segv_handler = signal(SIGSEGV, h);
# ifdef SIGBUS
old_bus_handler = signal(SIGBUS, h);
# endif
# endif
}
# endif /* NEED_FIND_LIMIT || UNIX_LIKE */
# if defined(NEED_FIND_LIMIT) \
|| (defined(USE_PROC_FOR_LIBRARIES) && defined(THREADS))
/* Some tools to implement HEURISTIC2 */
# define MIN_PAGE_SIZE 256 /* Smallest conceivable page size, bytes */
/*ARGSUSED*/
STATIC void GC_fault_handler(int sig)
{
LONGJMP(GC_jmp_buf, 1);
}
GC_INNER void GC_setup_temporary_fault_handler(void)
{
/* Handler is process-wide, so this should only happen in */
/* one thread at a time. */
GC_ASSERT(I_HOLD_LOCK());
GC_set_and_save_fault_handler(GC_fault_handler);
}
GC_INNER void GC_reset_fault_handler(void)
{
# if defined(SUNOS5SIGS) || defined(IRIX5) \
|| defined(OSF1) || defined(HURD) || defined(NETBSD)
(void) sigaction(SIGSEGV, &old_segv_act, 0);
# if defined(IRIX5) && defined(_sigargs) /* Irix 5.x, not 6.x */ \
|| defined(HPUX) || defined(HURD) || defined(NETBSD) \
|| defined(FREEBSD)
(void) sigaction(SIGBUS, &old_bus_act, 0);
# endif
# else
(void) signal(SIGSEGV, old_segv_handler);
# ifdef SIGBUS
(void) signal(SIGBUS, old_bus_handler);
# endif
# endif
}
/* Return the first non-addressable location > p (up) or */
/* the smallest location q s.t. [q,p) is addressable (!up). */
/* We assume that p (up) or p-1 (!up) is addressable. */
/* Requires allocation lock. */
STATIC ptr_t GC_find_limit_with_bound(ptr_t p, GC_bool up, ptr_t bound)
{
static volatile ptr_t result;
/* Safer if static, since otherwise it may not be */
/* preserved across the longjmp. Can safely be */
/* static since it's only called with the */
/* allocation lock held. */
GC_ASSERT(I_HOLD_LOCK());
GC_setup_temporary_fault_handler();
if (SETJMP(GC_jmp_buf) == 0) {
result = (ptr_t)(((word)(p))
& ~(MIN_PAGE_SIZE-1));
for (;;) {
if (up) {
result += MIN_PAGE_SIZE;
if (result >= bound) return bound;
} else {
result -= MIN_PAGE_SIZE;
if (result <= bound) return bound;
}
GC_noop1((word)(*result));
}
}
GC_reset_fault_handler();
if (!up) {
result += MIN_PAGE_SIZE;
}
return(result);
}
ptr_t GC_find_limit(ptr_t p, GC_bool up)
{
return GC_find_limit_with_bound(p, up, up ? (ptr_t)(word)(-1) : 0);
}
# endif /* NEED_FIND_LIMIT || USE_PROC_FOR_LIBRARIES */
#ifdef HPUX_STACKBOTTOM
#include <sys/param.h>
#include <sys/pstat.h>
GC_INNER ptr_t GC_get_register_stack_base(void)
{
struct pst_vm_status vm_status;
int i = 0;
while (pstat_getprocvm(&vm_status, sizeof(vm_status), 0, i++) == 1) {
if (vm_status.pst_type == PS_RSESTACK) {
return (ptr_t) vm_status.pst_vaddr;
}
}
/* old way to get the register stackbottom */
return (ptr_t)(((word)GC_stackbottom - BACKING_STORE_DISPLACEMENT - 1)
& ~(BACKING_STORE_ALIGNMENT - 1));
}
#endif /* HPUX_STACK_BOTTOM */
#ifdef LINUX_STACKBOTTOM
# include <sys/types.h>
# include <sys/stat.h>
# define STAT_SKIP 27 /* Number of fields preceding startstack */
/* field in /proc/self/stat */
# ifdef USE_LIBC_PRIVATES
# pragma weak __libc_stack_end
extern ptr_t __libc_stack_end;
# endif
# ifdef IA64
# ifdef USE_LIBC_PRIVATES
# pragma weak __libc_ia64_register_backing_store_base
extern ptr_t __libc_ia64_register_backing_store_base;
# endif
GC_INNER ptr_t GC_get_register_stack_base(void)
{
ptr_t result;
# ifdef USE_LIBC_PRIVATES
if (0 != &__libc_ia64_register_backing_store_base
&& 0 != __libc_ia64_register_backing_store_base) {
/* Glibc 2.2.4 has a bug such that for dynamically linked */
/* executables __libc_ia64_register_backing_store_base is */
/* defined but uninitialized during constructor calls. */
/* Hence we check for both nonzero address and value. */
return __libc_ia64_register_backing_store_base;
}
# endif
result = backing_store_base_from_proc();
if (0 == result) {
result = GC_find_limit(GC_save_regs_in_stack(), FALSE);
/* Now seems to work better than constant displacement */
/* heuristic used in 6.X versions. The latter seems to */
/* fail for 2.6 kernels. */
}
return result;
}
# endif /* IA64 */
STATIC ptr_t GC_linux_main_stack_base(void)
{
/* We read the stack base value from /proc/self/stat. We do this */
/* using direct I/O system calls in order to avoid calling malloc */
/* in case REDIRECT_MALLOC is defined. */
# ifndef STAT_READ
/* Also defined in pthread_support.c. */
# define STAT_BUF_SIZE 4096
# define STAT_READ read
# endif
/* Should probably call the real read, if read is wrapped. */
char stat_buf[STAT_BUF_SIZE];
int f;
word result;
int i, buf_offset = 0, len;
/* First try the easy way. This should work for glibc 2.2 */
/* This fails in a prelinked ("prelink" command) executable */
/* since the correct value of __libc_stack_end never */
/* becomes visible to us. The second test works around */
/* this. */
# ifdef USE_LIBC_PRIVATES
if (0 != &__libc_stack_end && 0 != __libc_stack_end ) {
# if defined(IA64)
/* Some versions of glibc set the address 16 bytes too */
/* low while the initialization code is running. */
if (((word)__libc_stack_end & 0xfff) + 0x10 < 0x1000) {
return __libc_stack_end + 0x10;
} /* Otherwise it's not safe to add 16 bytes and we fall */
/* back to using /proc. */
# elif defined(SPARC)
/* Older versions of glibc for 64-bit Sparc do not set
* this variable correctly, it gets set to either zero
* or one.
*/
if (__libc_stack_end != (ptr_t) (unsigned long)0x1)
return __libc_stack_end;
# else
return __libc_stack_end;
# endif
}
# endif
f = open("/proc/self/stat", O_RDONLY);
if (f < 0)
ABORT("Couldn't read /proc/self/stat");
len = STAT_READ(f, stat_buf, STAT_BUF_SIZE);
close(f);
/* Skip the required number of fields. This number is hopefully */
/* constant across all Linux implementations. */
for (i = 0; i < STAT_SKIP; ++i) {
while (buf_offset < len && isspace(stat_buf[buf_offset++])) {
/* empty */
}
while (buf_offset < len && !isspace(stat_buf[buf_offset++])) {
/* empty */
}
}
/* Skip spaces. */
while (buf_offset < len && isspace(stat_buf[buf_offset])) {
buf_offset++;
}
/* Find the end of the number and cut the buffer there. */
for (i = 0; buf_offset + i < len; i++) {
if (!isdigit(stat_buf[buf_offset + i])) break;
}
if (buf_offset + i >= len) ABORT("Could not parse /proc/self/stat");
stat_buf[buf_offset + i] = '\0';
result = (word)STRTOULL(&stat_buf[buf_offset], NULL, 10);
if (result < 0x100000 || (result & (sizeof(word) - 1)) != 0)
ABORT("Absurd stack bottom value");
return (ptr_t)result;
}
#endif /* LINUX_STACKBOTTOM */
#ifdef FREEBSD_STACKBOTTOM
/* This uses an undocumented sysctl call, but at least one expert */
/* believes it will stay. */
# include <unistd.h>
# include <sys/types.h>
# include <sys/sysctl.h>
STATIC ptr_t GC_freebsd_main_stack_base(void)
{
int nm[2] = {CTL_KERN, KERN_USRSTACK};
ptr_t base;
size_t len = sizeof(ptr_t);
int r = sysctl(nm, 2, &base, &len, NULL, 0);
if (r) ABORT("Error getting main stack base");
return base;
}
#endif /* FREEBSD_STACKBOTTOM */
#if defined(ECOS) || defined(NOSYS)
ptr_t GC_get_main_stack_base(void)
{
return STACKBOTTOM;
}
# define GET_MAIN_STACKBASE_SPECIAL
#elif !defined(BEOS) && !defined(AMIGA) && !defined(OS2) \
&& !defined(MSWIN32) && !defined(MSWINCE) && !defined(CYGWIN32) \
&& !defined(GC_OPENBSD_THREADS) \
&& (!defined(GC_SOLARIS_THREADS) || defined(_STRICT_STDC))
# if defined(LINUX) && defined(USE_GET_STACKBASE_FOR_MAIN)
# include <pthread.h>
# elif defined(DARWIN) && !defined(NO_PTHREAD_GET_STACKADDR_NP)
/* We could use pthread_get_stackaddr_np even in case of a */
/* single-threaded gclib (there is no -lpthread on Darwin). */
# include <pthread.h>
# undef STACKBOTTOM
# define STACKBOTTOM (ptr_t)pthread_get_stackaddr_np(pthread_self())
# endif
ptr_t GC_get_main_stack_base(void)
{
ptr_t result; /* also used as "dummy" to get the approx. sp value */
# if defined(LINUX) && !defined(NACL) \
&& (defined(USE_GET_STACKBASE_FOR_MAIN) \
|| (defined(THREADS) && !defined(REDIRECT_MALLOC)))
pthread_attr_t attr;
void *stackaddr;
size_t size;
if (pthread_getattr_np(pthread_self(), &attr) == 0) {
if (pthread_attr_getstack(&attr, &stackaddr, &size) == 0
&& stackaddr != NULL) {
pthread_attr_destroy(&attr);
# ifdef STACK_GROWS_DOWN
stackaddr = (char *)stackaddr + size;
# endif
return (ptr_t)stackaddr;
}
pthread_attr_destroy(&attr);
}
WARN("pthread_getattr_np or pthread_attr_getstack failed"
" for main thread\n", 0);
# endif
# ifdef STACKBOTTOM
result = STACKBOTTOM;
# else
# define STACKBOTTOM_ALIGNMENT_M1 ((word)STACK_GRAN - 1)
# ifdef HEURISTIC1
# ifdef STACK_GROWS_DOWN
result = (ptr_t)((((word)(&result)) + STACKBOTTOM_ALIGNMENT_M1)
& ~STACKBOTTOM_ALIGNMENT_M1);
# else
result = (ptr_t)(((word)(&result)) & ~STACKBOTTOM_ALIGNMENT_M1);
# endif
# endif /* HEURISTIC1 */
# ifdef LINUX_STACKBOTTOM
result = GC_linux_main_stack_base();
# endif
# ifdef FREEBSD_STACKBOTTOM
result = GC_freebsd_main_stack_base();
# endif
# ifdef HEURISTIC2
# ifdef STACK_GROWS_DOWN
result = GC_find_limit((ptr_t)(&result), TRUE);
# ifdef HEURISTIC2_LIMIT
if (result > HEURISTIC2_LIMIT
&& (ptr_t)(&result) < HEURISTIC2_LIMIT) {
result = HEURISTIC2_LIMIT;
}
# endif
# else
result = GC_find_limit((ptr_t)(&result), FALSE);
# ifdef HEURISTIC2_LIMIT
if (result < HEURISTIC2_LIMIT
&& (ptr_t)(&result) > HEURISTIC2_LIMIT) {
result = HEURISTIC2_LIMIT;
}
# endif
# endif
# endif /* HEURISTIC2 */
# ifdef STACK_GROWS_DOWN
if (result == 0)
result = (ptr_t)(signed_word)(-sizeof(ptr_t));
# endif
# endif
GC_ASSERT((ptr_t)(&result) HOTTER_THAN result);
return(result);
}
# define GET_MAIN_STACKBASE_SPECIAL
#endif /* !AMIGA, !BEOS, !OPENBSD, !OS2, !Windows */
#if (defined(GC_LINUX_THREADS) || defined(PLATFORM_ANDROID)) && !defined(NACL)
# include <pthread.h>
/* extern int pthread_getattr_np(pthread_t, pthread_attr_t *); */
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *b)
{
pthread_attr_t attr;
size_t size;
# ifdef IA64
DCL_LOCK_STATE;
# endif
if (pthread_getattr_np(pthread_self(), &attr) != 0) {
WARN("pthread_getattr_np failed\n", 0);
return GC_UNIMPLEMENTED;
}
if (pthread_attr_getstack(&attr, &(b -> mem_base), &size) != 0) {
ABORT("pthread_attr_getstack failed");
}
pthread_attr_destroy(&attr);
# ifdef STACK_GROWS_DOWN
b -> mem_base = (char *)(b -> mem_base) + size;
# endif
# ifdef IA64
/* We could try backing_store_base_from_proc, but that's safe */
/* only if no mappings are being asynchronously created. */
/* Subtracting the size from the stack base doesn't work for at */
/* least the main thread. */
LOCK();
{
IF_CANCEL(int cancel_state;)
ptr_t bsp;
ptr_t next_stack;
DISABLE_CANCEL(cancel_state);
bsp = GC_save_regs_in_stack();
next_stack = GC_greatest_stack_base_below(bsp);
if (0 == next_stack) {
b -> reg_base = GC_find_limit(bsp, FALSE);
} else {
/* Avoid walking backwards into preceding memory stack and */
/* growing it. */
b -> reg_base = GC_find_limit_with_bound(bsp, FALSE, next_stack);
}
RESTORE_CANCEL(cancel_state);
}
UNLOCK();
# endif
return GC_SUCCESS;
}
# define HAVE_GET_STACK_BASE
#endif /* GC_LINUX_THREADS */
#if defined(GC_DARWIN_THREADS) && !defined(NO_PTHREAD_GET_STACKADDR_NP)
# include <pthread.h>
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *b)
{
# ifdef GC_ASSERTIONS
int dummy;
# endif
/* pthread_get_stackaddr_np() should return stack bottom (highest */
/* stack address plus 1). */
b->mem_base = pthread_get_stackaddr_np(pthread_self());
GC_ASSERT((void *)&dummy HOTTER_THAN b->mem_base);
return GC_SUCCESS;
}
# define HAVE_GET_STACK_BASE
#endif /* GC_DARWIN_THREADS */
#ifdef GC_OPENBSD_THREADS
# include <sys/signal.h>
# include <pthread.h>
# include <pthread_np.h>
/* Find the stack using pthread_stackseg_np(). */
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
stack_t stack;
pthread_stackseg_np(pthread_self(), &stack);
sb->mem_base = stack.ss_sp;
return GC_SUCCESS;
}
# define HAVE_GET_STACK_BASE
#endif /* GC_OPENBSD_THREADS */
#if defined(GC_SOLARIS_THREADS) && !defined(_STRICT_STDC)
# include <thread.h>
# include <signal.h>
# include <pthread.h>
/* These variables are used to cache ss_sp value for the primordial */
/* thread (it's better not to call thr_stksegment() twice for this */
/* thread - see JDK bug #4352906). */
static pthread_t stackbase_main_self = 0;
/* 0 means stackbase_main_ss_sp value is unset. */
static void *stackbase_main_ss_sp = NULL;
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *b)
{
stack_t s;
pthread_t self = pthread_self();
if (self == stackbase_main_self)
{
/* If the client calls GC_get_stack_base() from the main thread */
/* then just return the cached value. */
b -> mem_base = stackbase_main_ss_sp;
GC_ASSERT(b -> mem_base != NULL);
return GC_SUCCESS;
}
if (thr_stksegment(&s)) {
/* According to the manual, the only failure error code returned */
/* is EAGAIN meaning "the information is not available due to the */
/* thread is not yet completely initialized or it is an internal */
/* thread" - this shouldn't happen here. */
ABORT("thr_stksegment failed");
}
/* s.ss_sp holds the pointer to the stack bottom. */
GC_ASSERT((void *)&s HOTTER_THAN s.ss_sp);
if (!stackbase_main_self && thr_main() != 0)
{
/* Cache the stack base value for the primordial thread (this */
/* is done during GC_init, so there is no race). */
stackbase_main_ss_sp = s.ss_sp;
stackbase_main_self = self;
}
b -> mem_base = s.ss_sp;
return GC_SUCCESS;
}
# define HAVE_GET_STACK_BASE
#endif /* GC_SOLARIS_THREADS */
#ifndef HAVE_GET_STACK_BASE
/* Retrieve stack base. */
/* Using the GC_find_limit version is risky. */
/* On IA64, for example, there is no guard page between the */
/* stack of one thread and the register backing store of the */
/* next. Thus this is likely to identify way too large a */
/* "stack" and thus at least result in disastrous performance. */
/* FIXME - Implement better strategies here. */
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *b)
{
# ifdef NEED_FIND_LIMIT
int dummy;
IF_CANCEL(int cancel_state;)
DCL_LOCK_STATE;
LOCK();
DISABLE_CANCEL(cancel_state); /* May be unnecessary? */
# ifdef STACK_GROWS_DOWN
b -> mem_base = GC_find_limit((ptr_t)(&dummy), TRUE);
# ifdef IA64
b -> reg_base = GC_find_limit(GC_save_regs_in_stack(), FALSE);
# endif
# else
b -> mem_base = GC_find_limit(&dummy, FALSE);
# endif
RESTORE_CANCEL(cancel_state);
UNLOCK();
return GC_SUCCESS;
# else
return GC_UNIMPLEMENTED;
# endif
}
#endif /* !HAVE_GET_STACK_BASE */
#ifndef GET_MAIN_STACKBASE_SPECIAL
/* This is always called from the main thread. Default implementation. */
ptr_t GC_get_main_stack_base(void)
{
struct GC_stack_base sb;
if (GC_get_stack_base(&sb) != GC_SUCCESS)
ABORT("GC_get_stack_base failed");
GC_ASSERT((void *)&sb HOTTER_THAN sb.mem_base);
return (ptr_t)sb.mem_base;
}
#endif /* !GET_MAIN_STACKBASE_SPECIAL */
/* Register static data segment(s) as roots. If more data segments are */
/* added later then they need to be registered at that point (as we do */
/* with SunOS dynamic loading), or GC_mark_roots needs to check for */
/* them (as we do with PCR). Called with allocator lock held. */
# ifdef OS2
void GC_register_data_segments(void)
{
PTIB ptib;
PPIB ppib;
HMODULE module_handle;
# define PBUFSIZ 512
UCHAR path[PBUFSIZ];
FILE * myexefile;
struct exe_hdr hdrdos; /* MSDOS header. */
struct e32_exe hdr386; /* Real header for my executable */
struct o32_obj seg; /* Currrent segment */
int nsegs;
if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) {
ABORT("DosGetInfoBlocks failed");
}
module_handle = ppib -> pib_hmte;
if (DosQueryModuleName(module_handle, PBUFSIZ, path) != NO_ERROR) {
GC_err_printf("DosQueryModuleName failed\n");
ABORT("DosGetInfoBlocks failed");
}
myexefile = fopen(path, "rb");
if (myexefile == 0) {
if (GC_print_stats) {
GC_err_puts("Couldn't open executable ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Failed to open executable");
}
if (fread((char *)(&hdrdos), 1, sizeof(hdrdos), myexefile)
< sizeof(hdrdos)) {
if (GC_print_stats) {
GC_err_puts("Couldn't read MSDOS header from ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Couldn't read MSDOS header");
}
if (E_MAGIC(hdrdos) != EMAGIC) {
if (GC_print_stats) {
GC_err_puts("Executable has wrong DOS magic number: ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Bad DOS magic number");
}
if (fseek(myexefile, E_LFANEW(hdrdos), SEEK_SET) != 0) {
if (GC_print_stats) {
GC_err_puts("Seek to new header failed in ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Bad DOS magic number");
}
if (fread((char *)(&hdr386), 1, sizeof(hdr386), myexefile)
< sizeof(hdr386)) {
if (GC_print_stats) {
GC_err_puts("Couldn't read MSDOS header from ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Couldn't read OS/2 header");
}
if (E32_MAGIC1(hdr386) != E32MAGIC1 || E32_MAGIC2(hdr386) != E32MAGIC2) {
if (GC_print_stats) {
GC_err_puts("Executable has wrong OS/2 magic number: ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Bad OS/2 magic number");
}
if (E32_BORDER(hdr386) != E32LEBO || E32_WORDER(hdr386) != E32LEWO) {
if (GC_print_stats) {
GC_err_puts("Executable has wrong byte order: ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Bad byte order");
}
if (E32_CPU(hdr386) == E32CPU286) {
if (GC_print_stats) {
GC_err_puts("GC can't handle 80286 executables: ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Intel 80286 executables are unsupported");
}
if (fseek(myexefile, E_LFANEW(hdrdos) + E32_OBJTAB(hdr386),
SEEK_SET) != 0) {
if (GC_print_stats) {
GC_err_puts("Seek to object table failed: ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Seek to object table failed");
}
for (nsegs = E32_OBJCNT(hdr386); nsegs > 0; nsegs--) {
int flags;
if (fread((char *)(&seg), 1, sizeof(seg), myexefile) < sizeof(seg)) {
if (GC_print_stats) {
GC_err_puts("Couldn't read obj table entry from ");
GC_err_puts(path);
GC_err_puts("\n");
}
ABORT("Couldn't read obj table entry");
}
flags = O32_FLAGS(seg);
if (!(flags & OBJWRITE)) continue;
if (!(flags & OBJREAD)) continue;
if (flags & OBJINVALID) {
GC_err_printf("Object with invalid pages?\n");
continue;
}
GC_add_roots_inner((ptr_t)O32_BASE(seg),
(ptr_t)(O32_BASE(seg)+O32_SIZE(seg)), FALSE);
}
}
# else /* !OS2 */
# if defined(GWW_VDB)
# ifndef MEM_WRITE_WATCH
# define MEM_WRITE_WATCH 0x200000
# endif
# ifndef WRITE_WATCH_FLAG_RESET
# define WRITE_WATCH_FLAG_RESET 1
# endif
/* Since we can't easily check whether ULONG_PTR and SIZE_T are */
/* defined in Win32 basetsd.h, we define own ULONG_PTR. */
# define GC_ULONG_PTR word
typedef UINT (WINAPI * GetWriteWatch_type)(
DWORD, PVOID, GC_ULONG_PTR /* SIZE_T */,
PVOID *, GC_ULONG_PTR *, PULONG);
static GetWriteWatch_type GetWriteWatch_func;
static DWORD GetWriteWatch_alloc_flag;
# define GC_GWW_AVAILABLE() (GetWriteWatch_func != NULL)
static void detect_GetWriteWatch(void)
{
static GC_bool done;
HMODULE hK32;
if (done)
return;
# if defined(MPROTECT_VDB)
{
char * str = GETENV("GC_USE_GETWRITEWATCH");
# if defined(GC_PREFER_MPROTECT_VDB)
if (str == NULL || (*str == '0' && *(str + 1) == '\0')) {
/* GC_USE_GETWRITEWATCH is unset or set to "0". */
done = TRUE; /* falling back to MPROTECT_VDB strategy. */
/* This should work as if GWW_VDB is undefined. */
return;
}
# else
if (str != NULL && *str == '0' && *(str + 1) == '\0') {
/* GC_USE_GETWRITEWATCH is set "0". */
done = TRUE; /* falling back to MPROTECT_VDB strategy. */
return;
}
# endif
}
# endif
hK32 = GetModuleHandle(TEXT("kernel32.dll"));
if (hK32 != (HMODULE)0 &&
(GetWriteWatch_func = (GetWriteWatch_type)GetProcAddress(hK32,
"GetWriteWatch")) != NULL) {
/* Also check whether VirtualAlloc accepts MEM_WRITE_WATCH, */
/* as some versions of kernel32.dll have one but not the */
/* other, making the feature completely broken. */
void * page = VirtualAlloc(NULL, GC_page_size,
MEM_WRITE_WATCH | MEM_RESERVE,
PAGE_READWRITE);
if (page != NULL) {
PVOID pages[16];
GC_ULONG_PTR count = 16;
DWORD page_size;
/* Check that it actually works. In spite of some */
/* documentation it actually seems to exist on W2K. */
/* This test may be unnecessary, but ... */
if (GetWriteWatch_func(WRITE_WATCH_FLAG_RESET,
page, GC_page_size,
pages,
&count,
&page_size) != 0) {
/* GetWriteWatch always fails. */
GetWriteWatch_func = NULL;
} else {
GetWriteWatch_alloc_flag = MEM_WRITE_WATCH;
}
VirtualFree(page, GC_page_size, MEM_RELEASE);
} else {
/* GetWriteWatch will be useless. */
GetWriteWatch_func = NULL;
}
}
if (GC_print_stats) {
if (GetWriteWatch_func == NULL) {
GC_log_printf("Did not find a usable GetWriteWatch()\n");
} else {
GC_log_printf("Using GetWriteWatch()\n");
}
}
done = TRUE;
}
# else
# define GetWriteWatch_alloc_flag 0
# endif /* !GWW_VDB */
# if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32)
# ifdef MSWIN32
/* Unfortunately, we have to handle win32s very differently from NT, */
/* Since VirtualQuery has very different semantics. In particular, */
/* under win32s a VirtualQuery call on an unmapped page returns an */
/* invalid result. Under NT, GC_register_data_segments is a no-op */
/* and all real work is done by GC_register_dynamic_libraries. Under */
/* win32s, we cannot find the data segments associated with dll's. */
/* We register the main data segment here. */
GC_INNER GC_bool GC_no_win32_dlls = FALSE;
/* This used to be set for gcc, to avoid dealing with */
/* the structured exception handling issues. But we now have */
/* assembly code to do that right. */
GC_INNER GC_bool GC_wnt = FALSE;
/* This is a Windows NT derivative, i.e. NT, W2K, XP or later. */
GC_INNER void GC_init_win32(void)
{
/* Set GC_wnt. If we're running under win32s, assume that no DLLs */
/* will be loaded. I doubt anyone still runs win32s, but... */
DWORD v = GetVersion();
GC_wnt = !(v & 0x80000000);
GC_no_win32_dlls |= ((!GC_wnt) && (v & 0xff) <= 3);
# ifdef USE_MUNMAP
if (GC_no_win32_dlls) {
/* Turn off unmapping for safety (since may not work well with */
/* GlobalAlloc). */
GC_unmap_threshold = 0;
}
# endif
}
/* Return the smallest address a such that VirtualQuery */
/* returns correct results for all addresses between a and start. */
/* Assumes VirtualQuery returns correct information for start. */
STATIC ptr_t GC_least_described_address(ptr_t start)
{
MEMORY_BASIC_INFORMATION buf;
size_t result;
LPVOID limit;
ptr_t p;
LPVOID q;
limit = GC_sysinfo.lpMinimumApplicationAddress;
p = (ptr_t)((word)start & ~(GC_page_size - 1));
for (;;) {
q = (LPVOID)(p - GC_page_size);
if ((ptr_t)q > (ptr_t)p /* underflow */ || q < limit) break;
result = VirtualQuery(q, &buf, sizeof(buf));
if (result != sizeof(buf) || buf.AllocationBase == 0) break;
p = (ptr_t)(buf.AllocationBase);
}
return p;
}
# endif /* MSWIN32 */
# ifndef REDIRECT_MALLOC
/* We maintain a linked list of AllocationBase values that we know */
/* correspond to malloc heap sections. Currently this is only called */
/* during a GC. But there is some hope that for long running */
/* programs we will eventually see most heap sections. */
/* In the long run, it would be more reliable to occasionally walk */
/* the malloc heap with HeapWalk on the default heap. But that */
/* apparently works only for NT-based Windows. */
STATIC size_t GC_max_root_size = 100000; /* Appr. largest root size. */
# ifndef CYGWIN32
/* In the long run, a better data structure would also be nice ... */
STATIC struct GC_malloc_heap_list {
void * allocation_base;
struct GC_malloc_heap_list *next;
} *GC_malloc_heap_l = 0;
/* Is p the base of one of the malloc heap sections we already know */
/* about? */
STATIC GC_bool GC_is_malloc_heap_base(ptr_t p)
{
struct GC_malloc_heap_list *q = GC_malloc_heap_l;
while (0 != q) {
if (q -> allocation_base == p) return TRUE;
q = q -> next;
}
return FALSE;
}
STATIC void *GC_get_allocation_base(void *p)
{
MEMORY_BASIC_INFORMATION buf;
size_t result = VirtualQuery(p, &buf, sizeof(buf));
if (result != sizeof(buf)) {
ABORT("Weird VirtualQuery result");
}
return buf.AllocationBase;
}
GC_INNER void GC_add_current_malloc_heap(void)
{
struct GC_malloc_heap_list *new_l =
malloc(sizeof(struct GC_malloc_heap_list));
void * candidate = GC_get_allocation_base(new_l);
if (new_l == 0) return;
if (GC_is_malloc_heap_base(candidate)) {
/* Try a little harder to find malloc heap. */
size_t req_size = 10000;
do {
void *p = malloc(req_size);
if (0 == p) {
free(new_l);
return;
}
candidate = GC_get_allocation_base(p);
free(p);
req_size *= 2;
} while (GC_is_malloc_heap_base(candidate)
&& req_size < GC_max_root_size/10 && req_size < 500000);
if (GC_is_malloc_heap_base(candidate)) {
free(new_l);
return;
}
}
if (GC_print_stats)
GC_log_printf("Found new system malloc AllocationBase at %p\n",
candidate);
new_l -> allocation_base = candidate;
new_l -> next = GC_malloc_heap_l;
GC_malloc_heap_l = new_l;
}
# endif /* !CYGWIN32 */
# endif /* !REDIRECT_MALLOC */
STATIC word GC_n_heap_bases = 0; /* See GC_heap_bases. */
/* Is p the start of either the malloc heap, or of one of our */
/* heap sections? */
GC_INNER GC_bool GC_is_heap_base(ptr_t p)
{
unsigned i;
# ifndef REDIRECT_MALLOC
if (GC_root_size > GC_max_root_size) GC_max_root_size = GC_root_size;
# ifndef CYGWIN32
if (GC_is_malloc_heap_base(p)) return TRUE;
# endif
# endif
for (i = 0; i < GC_n_heap_bases; i++) {
if (GC_heap_bases[i] == p) return TRUE;
}
return FALSE;
}
#ifdef MSWIN32
STATIC void GC_register_root_section(ptr_t static_root)
{
MEMORY_BASIC_INFORMATION buf;
size_t result;
DWORD protect;
LPVOID p;
char * base;
char * limit, * new_limit;
if (!GC_no_win32_dlls) return;
p = base = limit = GC_least_described_address(static_root);
while (p < GC_sysinfo.lpMaximumApplicationAddress) {
result = VirtualQuery(p, &buf, sizeof(buf));
if (result != sizeof(buf) || buf.AllocationBase == 0
|| GC_is_heap_base(buf.AllocationBase)) break;
new_limit = (char *)p + buf.RegionSize;
protect = buf.Protect;
if (buf.State == MEM_COMMIT
&& is_writable(protect)) {
if ((char *)p == limit) {
limit = new_limit;
} else {
if (base != limit) GC_add_roots_inner(base, limit, FALSE);
base = p;
limit = new_limit;
}
}
if (p > (LPVOID)new_limit /* overflow */) break;
p = (LPVOID)new_limit;
}
if (base != limit) GC_add_roots_inner(base, limit, FALSE);
}
#endif /* MSWIN32 */
void GC_register_data_segments(void)
{
# ifdef MSWIN32
static char dummy;
GC_register_root_section((ptr_t)(&dummy));
# endif
}
# else /* !OS2 && !Windows */
# if (defined(SVR4) || defined(AUX) || defined(DGUX) \
|| (defined(LINUX) && defined(SPARC))) && !defined(PCR)
ptr_t GC_SysVGetDataStart(size_t max_page_size, ptr_t etext_addr)
{
word text_end = ((word)(etext_addr) + sizeof(word) - 1)
& ~(sizeof(word) - 1);
/* etext rounded to word boundary */
word next_page = ((text_end + (word)max_page_size - 1)
& ~((word)max_page_size - 1));
word page_offset = (text_end & ((word)max_page_size - 1));
volatile char * result = (char *)(next_page + page_offset);
/* Note that this isn't equivalent to just adding */
/* max_page_size to &etext if &etext is at a page boundary */
GC_setup_temporary_fault_handler();
if (SETJMP(GC_jmp_buf) == 0) {
/* Try writing to the address. */
*result = *result;
GC_reset_fault_handler();
} else {
GC_reset_fault_handler();
/* We got here via a longjmp. The address is not readable. */
/* This is known to happen under Solaris 2.4 + gcc, which place */
/* string constants in the text segment, but after etext. */
/* Use plan B. Note that we now know there is a gap between */
/* text and data segments, so plan A bought us something. */
result = (char *)GC_find_limit((ptr_t)(DATAEND), FALSE);
}
return((ptr_t)result);
}
# endif
# if defined(FREEBSD) && !defined(PCR) && (defined(I386) || defined(X86_64) \
|| defined(powerpc) || defined(__powerpc__))
/* Its unclear whether this should be identical to the above, or */
/* whether it should apply to non-X86 architectures. */
/* For now we don't assume that there is always an empty page after */
/* etext. But in some cases there actually seems to be slightly more. */
/* This also deals with holes between read-only data and writable data. */
ptr_t GC_FreeBSDGetDataStart(size_t max_page_size, ptr_t etext_addr)
{
word text_end = ((word)(etext_addr) + sizeof(word) - 1)
& ~(sizeof(word) - 1);
/* etext rounded to word boundary */
volatile word next_page = (text_end + (word)max_page_size - 1)
& ~((word)max_page_size - 1);
volatile ptr_t result = (ptr_t)text_end;
GC_setup_temporary_fault_handler();
if (SETJMP(GC_jmp_buf) == 0) {
/* Try reading at the address. */
/* This should happen before there is another thread. */
for (; next_page < (word)(DATAEND); next_page += (word)max_page_size)
*(volatile char *)next_page;
GC_reset_fault_handler();
} else {
GC_reset_fault_handler();
/* As above, we go to plan B */
result = GC_find_limit((ptr_t)(DATAEND), FALSE);
}
return(result);
}
# endif /* FREEBSD */
#ifdef AMIGA
# define GC_AMIGA_DS
# include "extra/AmigaOS.c"
# undef GC_AMIGA_DS
#elif defined(OPENBSD)
/* Depending on arch alignment, there can be multiple holes */
/* between DATASTART and DATAEND. Scan in DATASTART .. DATAEND */
/* and register each region. */
void GC_register_data_segments(void)
{
ptr_t region_start = DATASTART;
ptr_t region_end;
for (;;) {
region_end = GC_find_limit_openbsd(region_start, DATAEND);
GC_add_roots_inner(region_start, region_end, FALSE);
if (region_end >= DATAEND)
break;
region_start = GC_skip_hole_openbsd(region_end, DATAEND);
}
}
# else /* !OS2 && !Windows && !AMIGA && !OPENBSD */
void GC_register_data_segments(void)
{
# if !defined(PCR) && !defined(MACOS)
# if defined(REDIRECT_MALLOC) && defined(GC_SOLARIS_THREADS)
/* As of Solaris 2.3, the Solaris threads implementation */
/* allocates the data structure for the initial thread with */
/* sbrk at process startup. It needs to be scanned, so that */
/* we don't lose some malloc allocated data structures */
/* hanging from it. We're on thin ice here ... */
extern caddr_t sbrk(int);
GC_add_roots_inner(DATASTART, (ptr_t)sbrk(0), FALSE);
# else
GC_add_roots_inner(DATASTART, (ptr_t)(DATAEND), FALSE);
# if defined(DATASTART2)
GC_add_roots_inner(DATASTART2, (ptr_t)(DATAEND2), FALSE);
# endif
# endif
# endif
# if defined(MACOS)
{
# if defined(THINK_C)
extern void* GC_MacGetDataStart(void);
/* globals begin above stack and end at a5. */
GC_add_roots_inner((ptr_t)GC_MacGetDataStart(),
(ptr_t)LMGetCurrentA5(), FALSE);
# else
# if defined(__MWERKS__)
# if !__POWERPC__
extern void* GC_MacGetDataStart(void);
/* MATTHEW: Function to handle Far Globals (CW Pro 3) */
# if __option(far_data)
extern void* GC_MacGetDataEnd(void);
# endif
/* globals begin above stack and end at a5. */
GC_add_roots_inner((ptr_t)GC_MacGetDataStart(),
(ptr_t)LMGetCurrentA5(), FALSE);
/* MATTHEW: Handle Far Globals */
# if __option(far_data)
/* Far globals follow he QD globals: */
GC_add_roots_inner((ptr_t)LMGetCurrentA5(),
(ptr_t)GC_MacGetDataEnd(), FALSE);
# endif
# else
extern char __data_start__[], __data_end__[];
GC_add_roots_inner((ptr_t)&__data_start__,
(ptr_t)&__data_end__, FALSE);
# endif /* __POWERPC__ */
# endif /* __MWERKS__ */
# endif /* !THINK_C */
}
# endif /* MACOS */
/* Dynamic libraries are added at every collection, since they may */
/* change. */
}
# endif /* ! AMIGA */
# endif /* ! MSWIN32 && ! MSWINCE*/
# endif /* ! OS2 */
/*
* Auxiliary routines for obtaining memory from OS.
*/
# if !defined(OS2) && !defined(PCR) && !defined(AMIGA) && !defined(MSWIN32) \
&& !defined(MSWINCE) && !defined(MACOS) && !defined(DOS4GW) \
&& !defined(NONSTOP) && !defined(SN_TARGET_PS3) && !defined(RTEMS) \
&& !defined(__CC_ARM)
# define SBRK_ARG_T ptrdiff_t
#if defined(MMAP_SUPPORTED)
#ifdef USE_MMAP_FIXED
# define GC_MMAP_FLAGS MAP_FIXED | MAP_PRIVATE
/* Seems to yield better performance on Solaris 2, but can */
/* be unreliable if something is already mapped at the address. */
#else
# define GC_MMAP_FLAGS MAP_PRIVATE
#endif
#ifdef USE_MMAP_ANON
# define zero_fd -1
# if defined(MAP_ANONYMOUS)
# define OPT_MAP_ANON MAP_ANONYMOUS
# else
# define OPT_MAP_ANON MAP_ANON
# endif
#else
static int zero_fd;
# define OPT_MAP_ANON 0
#endif
#ifndef HEAP_START
# define HEAP_START ((ptr_t)0)
#endif
STATIC ptr_t GC_unix_mmap_get_mem(word bytes)
{
void *result;
static ptr_t last_addr = HEAP_START;
# ifndef USE_MMAP_ANON
static GC_bool initialized = FALSE;
if (!initialized) {
zero_fd = open("/dev/zero", O_RDONLY);
fcntl(zero_fd, F_SETFD, FD_CLOEXEC);
initialized = TRUE;
}
# endif
if (bytes & (GC_page_size - 1)) ABORT("Bad GET_MEM arg");
result = mmap(last_addr, bytes, (PROT_READ | PROT_WRITE)
| (GC_pages_executable ? PROT_EXEC : 0),
GC_MMAP_FLAGS | OPT_MAP_ANON, zero_fd, 0/* offset */);
# undef IGNORE_PAGES_EXECUTABLE
if (result == MAP_FAILED) return(0);
last_addr = (ptr_t)result + bytes + GC_page_size - 1;
last_addr = (ptr_t)((word)last_addr & ~(GC_page_size - 1));
# if !defined(LINUX)
if (last_addr == 0) {
/* Oops. We got the end of the address space. This isn't */
/* usable by arbitrary C code, since one-past-end pointers */
/* don't work, so we discard it and try again. */
munmap(result, (size_t)(-GC_page_size) - (size_t)result);
/* Leave last page mapped, so we can't repeat. */
return GC_unix_mmap_get_mem(bytes);
}
# else
GC_ASSERT(last_addr != 0);
# endif
return((ptr_t)result);
}
# endif /* MMAP_SUPPORTED */
#if defined(USE_MMAP)
ptr_t GC_unix_get_mem(word bytes)
{
return GC_unix_mmap_get_mem(bytes);
}
#else /* !USE_MMAP */
STATIC ptr_t GC_unix_sbrk_get_mem(word bytes)
{
ptr_t result;
# ifdef IRIX5
/* Bare sbrk isn't thread safe. Play by malloc rules. */
/* The equivalent may be needed on other systems as well. */
__LOCK_MALLOC();
# endif
{
ptr_t cur_brk = (ptr_t)sbrk(0);
SBRK_ARG_T lsbs = (word)cur_brk & (GC_page_size-1);
if ((SBRK_ARG_T)bytes < 0) {
result = 0; /* too big */
goto out;
}
if (lsbs != 0) {
if((ptr_t)sbrk(GC_page_size - lsbs) == (ptr_t)(-1)) {
result = 0;
goto out;
}
}
# ifdef ADD_HEAP_GUARD_PAGES
/* This is useful for catching severe memory overwrite problems that */
/* span heap sections. It shouldn't otherwise be turned on. */
{
ptr_t guard = (ptr_t)sbrk((SBRK_ARG_T)GC_page_size);
if (mprotect(guard, GC_page_size, PROT_NONE) != 0)
ABORT("ADD_HEAP_GUARD_PAGES: mprotect failed");
}
# endif /* ADD_HEAP_GUARD_PAGES */
result = (ptr_t)sbrk((SBRK_ARG_T)bytes);
if (result == (ptr_t)(-1)) result = 0;
}
out:
# ifdef IRIX5
__UNLOCK_MALLOC();
# endif
return(result);
}
ptr_t GC_unix_get_mem(word bytes)
{
# if defined(MMAP_SUPPORTED)
/* By default, we try both sbrk and mmap, in that order. */
static GC_bool sbrk_failed = FALSE;
ptr_t result = 0;
if (!sbrk_failed) result = GC_unix_sbrk_get_mem(bytes);
if (0 == result) {
sbrk_failed = TRUE;
result = GC_unix_mmap_get_mem(bytes);
}
if (0 == result) {
/* Try sbrk again, in case sbrk memory became available. */
result = GC_unix_sbrk_get_mem(bytes);
}
return result;
# else /* !MMAP_SUPPORTED */
return GC_unix_sbrk_get_mem(bytes);
# endif
}
#endif /* !USE_MMAP */
# endif /* UN*X */
# ifdef OS2
void * os2_alloc(size_t bytes)
{
void * result;
if (DosAllocMem(&result, bytes, (PAG_READ | PAG_WRITE | PAG_COMMIT)
| (GC_pages_executable ? PAG_EXECUTE : 0))
!= NO_ERROR) {
return(0);
}
/* FIXME: What's the purpose of this recursion? (Probably, if */
/* DosAllocMem returns memory at 0 address then just retry once.) */
if (result == 0) return(os2_alloc(bytes));
return(result);
}
# endif /* OS2 */
# if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32)
GC_INNER SYSTEM_INFO GC_sysinfo;
# endif
#ifdef MSWIN32
# ifdef USE_GLOBAL_ALLOC
# define GLOBAL_ALLOC_TEST 1
# else
# define GLOBAL_ALLOC_TEST GC_no_win32_dlls
# endif
# ifdef GC_USE_MEM_TOP_DOWN
STATIC DWORD GC_mem_top_down = MEM_TOP_DOWN;
/* Use GC_USE_MEM_TOP_DOWN for better 64-bit */
/* testing. Otherwise all addresses tend to */
/* end up in first 4GB, hiding bugs. */
# else
STATIC DWORD GC_mem_top_down = 0;
# endif
#endif /* MSWIN32 */
#if defined(MSWIN32) || defined(CYGWIN32)
ptr_t GC_win32_get_mem(word bytes)
{
ptr_t result;
# ifdef CYGWIN32
result = GC_unix_get_mem(bytes);
# else
if (GLOBAL_ALLOC_TEST) {
/* VirtualAlloc doesn't like PAGE_EXECUTE_READWRITE. */
/* There are also unconfirmed rumors of other */
/* problems, so we dodge the issue. */
result = (ptr_t) GlobalAlloc(0, bytes + HBLKSIZE);
result = (ptr_t)(((word)result + HBLKSIZE - 1) & ~(HBLKSIZE-1));
} else {
/* VirtualProtect only works on regions returned by a */
/* single VirtualAlloc call. Thus we allocate one */
/* extra page, which will prevent merging of blocks */
/* in separate regions, and eliminate any temptation */
/* to call VirtualProtect on a range spanning regions. */
/* This wastes a small amount of memory, and risks */
/* increased fragmentation. But better alternatives */
/* would require effort. */
# ifdef MPROTECT_VDB
/* We can't check for GC_incremental here (because */
/* GC_enable_incremental() might be called some time */
/* later after the GC initialization). */
# ifdef GWW_VDB
# define VIRTUAL_ALLOC_PAD (GC_GWW_AVAILABLE() ? 0 : 1)
# else
# define VIRTUAL_ALLOC_PAD 1
# endif
# else
# define VIRTUAL_ALLOC_PAD 0
# endif
/* Pass the MEM_WRITE_WATCH only if GetWriteWatch-based */
/* VDBs are enabled and the GetWriteWatch function is */
/* available. Otherwise we waste resources or possibly */
/* cause VirtualAlloc to fail (observed in Windows 2000 */
/* SP2). */
result = (ptr_t) VirtualAlloc(NULL, bytes + VIRTUAL_ALLOC_PAD,
GetWriteWatch_alloc_flag
| (MEM_COMMIT | MEM_RESERVE)
| GC_mem_top_down,
GC_pages_executable ? PAGE_EXECUTE_READWRITE :
PAGE_READWRITE);
# undef IGNORE_PAGES_EXECUTABLE
}
# endif /* !CYGWIN32 */
if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result");
/* If I read the documentation correctly, this can */
/* only happen if HBLKSIZE > 64k or not a power of 2. */
if (GC_n_heap_bases >= MAX_HEAP_SECTS) ABORT("Too many heap sections");
if (0 != result) GC_heap_bases[GC_n_heap_bases++] = result;
return(result);
}
GC_API void GC_CALL GC_win32_free_heap(void)
{
# ifndef CYGWIN32
if (GC_no_win32_dlls)
# endif
{
while (GC_n_heap_bases-- > 0) {
# ifdef CYGWIN32
/* FIXME: Is it ok to use non-GC free() here? */
# else
GlobalFree(GC_heap_bases[GC_n_heap_bases]);
# endif
GC_heap_bases[GC_n_heap_bases] = 0;
}
}
}
#endif /* MSWIN32 || CYGWIN32 */
#ifdef AMIGA
# define GC_AMIGA_AM
# include "extra/AmigaOS.c"
# undef GC_AMIGA_AM
#endif
#ifdef MSWINCE
ptr_t GC_wince_get_mem(word bytes)
{
ptr_t result = 0; /* initialized to prevent warning. */
word i;
/* Round up allocation size to multiple of page size */
bytes = (bytes + GC_page_size-1) & ~(GC_page_size-1);
/* Try to find reserved, uncommitted pages */
for (i = 0; i < GC_n_heap_bases; i++) {
if (((word)(-(signed_word)GC_heap_lengths[i])
& (GC_sysinfo.dwAllocationGranularity-1))
>= bytes) {
result = GC_heap_bases[i] + GC_heap_lengths[i];
break;
}
}
if (i == GC_n_heap_bases) {
/* Reserve more pages */
word res_bytes = (bytes + GC_sysinfo.dwAllocationGranularity-1)
& ~(GC_sysinfo.dwAllocationGranularity-1);
/* If we ever support MPROTECT_VDB here, we will probably need to */
/* ensure that res_bytes is strictly > bytes, so that VirtualProtect */
/* never spans regions. It seems to be OK for a VirtualFree */
/* argument to span regions, so we should be OK for now. */
result = (ptr_t) VirtualAlloc(NULL, res_bytes,
MEM_RESERVE | MEM_TOP_DOWN,
GC_pages_executable ? PAGE_EXECUTE_READWRITE :
PAGE_READWRITE);
if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result");
/* If I read the documentation correctly, this can */
/* only happen if HBLKSIZE > 64k or not a power of 2. */
if (GC_n_heap_bases >= MAX_HEAP_SECTS) ABORT("Too many heap sections");
if (result == NULL) return NULL;
GC_heap_bases[GC_n_heap_bases] = result;
GC_heap_lengths[GC_n_heap_bases] = 0;
GC_n_heap_bases++;
}
/* Commit pages */
result = (ptr_t) VirtualAlloc(result, bytes, MEM_COMMIT,
GC_pages_executable ? PAGE_EXECUTE_READWRITE :
PAGE_READWRITE);
# undef IGNORE_PAGES_EXECUTABLE
if (result != NULL) {
if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result");
GC_heap_lengths[i] += bytes;
}
return(result);
}
#endif
#ifdef USE_MUNMAP
/* For now, this only works on Win32/WinCE and some Unix-like */
/* systems. If you have something else, don't define */
/* USE_MUNMAP. */
#if !defined(MSWIN32) && !defined(MSWINCE)
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#endif
/* Compute a page aligned starting address for the unmap */
/* operation on a block of size bytes starting at start. */
/* Return 0 if the block is too small to make this feasible. */
STATIC ptr_t GC_unmap_start(ptr_t start, size_t bytes)
{
ptr_t result;
/* Round start to next page boundary. */
result = (ptr_t)((word)(start + GC_page_size - 1) & ~(GC_page_size - 1));
if (result + GC_page_size > start + bytes) return 0;
return result;
}
/* Compute end address for an unmap operation on the indicated */
/* block. */
STATIC ptr_t GC_unmap_end(ptr_t start, size_t bytes)
{
return (ptr_t)((word)(start + bytes) & ~(GC_page_size - 1));
}
/* Under Win32/WinCE we commit (map) and decommit (unmap) */
/* memory using VirtualAlloc and VirtualFree. These functions */
/* work on individual allocations of virtual memory, made */
/* previously using VirtualAlloc with the MEM_RESERVE flag. */
/* The ranges we need to (de)commit may span several of these */
/* allocations; therefore we use VirtualQuery to check */
/* allocation lengths, and split up the range as necessary. */
/* We assume that GC_remap is called on exactly the same range */
/* as a previous call to GC_unmap. It is safe to consistently */
/* round the endpoints in both places. */
GC_INNER void GC_unmap(ptr_t start, size_t bytes)
{
ptr_t start_addr = GC_unmap_start(start, bytes);
ptr_t end_addr = GC_unmap_end(start, bytes);
word len = end_addr - start_addr;
if (0 == start_addr) return;
# if defined(MSWIN32) || defined(MSWINCE)
while (len != 0) {
MEMORY_BASIC_INFORMATION mem_info;
GC_word free_len;
if (VirtualQuery(start_addr, &mem_info, sizeof(mem_info))
!= sizeof(mem_info))
ABORT("Weird VirtualQuery result");
free_len = (len < mem_info.RegionSize) ? len : mem_info.RegionSize;
if (!VirtualFree(start_addr, free_len, MEM_DECOMMIT))
ABORT("VirtualFree failed");
GC_unmapped_bytes += free_len;
start_addr += free_len;
len -= free_len;
}
# else
/* We immediately remap it to prevent an intervening mmap from */
/* accidentally grabbing the same address space. */
{
void * result;
result = mmap(start_addr, len, PROT_NONE,
MAP_PRIVATE | MAP_FIXED | OPT_MAP_ANON,
zero_fd, 0/* offset */);
if (result != (void *)start_addr)
ABORT("mmap(PROT_NONE) failed");
}
GC_unmapped_bytes += len;
# endif
}
GC_INNER void GC_remap(ptr_t start, size_t bytes)
{
ptr_t start_addr = GC_unmap_start(start, bytes);
ptr_t end_addr = GC_unmap_end(start, bytes);
word len = end_addr - start_addr;
/* FIXME: Handle out-of-memory correctly (at least for Win32) */
# if defined(MSWIN32) || defined(MSWINCE)
ptr_t result;
if (0 == start_addr) return;
while (len != 0) {
MEMORY_BASIC_INFORMATION mem_info;
GC_word alloc_len;
if (VirtualQuery(start_addr, &mem_info, sizeof(mem_info))
!= sizeof(mem_info))
ABORT("Weird VirtualQuery result");
alloc_len = (len < mem_info.RegionSize) ? len : mem_info.RegionSize;
result = VirtualAlloc(start_addr, alloc_len, MEM_COMMIT,
GC_pages_executable ? PAGE_EXECUTE_READWRITE :
PAGE_READWRITE);
if (result != start_addr) {
if (GetLastError() == ERROR_NOT_ENOUGH_MEMORY ||
GetLastError() == ERROR_OUTOFMEMORY) {
ABORT("Not enough memory to process remapping");
} else {
ABORT("VirtualAlloc remapping failed");
}
}
GC_unmapped_bytes -= alloc_len;
start_addr += alloc_len;
len -= alloc_len;
}
# else
/* It was already remapped with PROT_NONE. */
int result;
if (0 == start_addr) return;
# ifndef NACL
result = mprotect(start_addr, len, (PROT_READ | PROT_WRITE)
| (GC_pages_executable ? PROT_EXEC : 0));
# else
{
/* NaCl does not expose mprotect, but mmap should work fine. */
void *mmap_result = mmap(start_addr, len, (PROT_READ | PROT_WRITE)
| (GC_pages_executable ? PROT_EXEC : 0),
MAP_PRIVATE | MAP_FIXED | OPT_MAP_ANON,
zero_fd, 0 /* offset */);
if (mmap_result != (void *)start_addr)
ABORT("mmap as mprotect failed");
/* Fake the return value as if mprotect succeeded. */
result = 0;
}
# endif /* NACL */
# undef IGNORE_PAGES_EXECUTABLE
if (result != 0) {
if (GC_print_stats)
GC_log_printf("Mprotect failed at %p (length %lu) with errno %d\n",
start_addr, (unsigned long)len, errno);
ABORT("mprotect remapping failed");
}
GC_unmapped_bytes -= len;
# endif
}
/* Two adjacent blocks have already been unmapped and are about to */
/* be merged. Unmap the whole block. This typically requires */
/* that we unmap a small section in the middle that was not previously */
/* unmapped due to alignment constraints. */
GC_INNER void GC_unmap_gap(ptr_t start1, size_t bytes1, ptr_t start2,
size_t bytes2)
{
ptr_t start1_addr = GC_unmap_start(start1, bytes1);
ptr_t end1_addr = GC_unmap_end(start1, bytes1);
ptr_t start2_addr = GC_unmap_start(start2, bytes2);
ptr_t start_addr = end1_addr;
ptr_t end_addr = start2_addr;
size_t len;
GC_ASSERT(start1 + bytes1 == start2);
if (0 == start1_addr) start_addr = GC_unmap_start(start1, bytes1 + bytes2);
if (0 == start2_addr) end_addr = GC_unmap_end(start1, bytes1 + bytes2);
if (0 == start_addr) return;
len = end_addr - start_addr;
# if defined(MSWIN32) || defined(MSWINCE)
while (len != 0) {
MEMORY_BASIC_INFORMATION mem_info;
GC_word free_len;
if (VirtualQuery(start_addr, &mem_info, sizeof(mem_info))
!= sizeof(mem_info))
ABORT("Weird VirtualQuery result");
free_len = (len < mem_info.RegionSize) ? len : mem_info.RegionSize;
if (!VirtualFree(start_addr, free_len, MEM_DECOMMIT))
ABORT("VirtualFree failed");
GC_unmapped_bytes += free_len;
start_addr += free_len;
len -= free_len;
}
# else
if (len != 0) {
/* Immediately remap as above. */
void * result;
result = mmap(start_addr, len, PROT_NONE,
MAP_PRIVATE | MAP_FIXED | OPT_MAP_ANON,
zero_fd, 0/* offset */);
if (result != (void *)start_addr)
ABORT("mmap(PROT_NONE) failed");
}
GC_unmapped_bytes += len;
# endif
}
#endif /* USE_MUNMAP */
/* Routine for pushing any additional roots. In THREADS */
/* environment, this is also responsible for marking from */
/* thread stacks. */
#ifndef THREADS
GC_INNER void (*GC_push_other_roots)(void) = 0;
#else /* THREADS */
# ifdef PCR
PCR_ERes GC_push_thread_stack(PCR_Th_T *t, PCR_Any dummy)
{
struct PCR_ThCtl_TInfoRep info;
PCR_ERes result;
info.ti_stkLow = info.ti_stkHi = 0;
result = PCR_ThCtl_GetInfo(t, &info);
GC_push_all_stack((ptr_t)(info.ti_stkLow), (ptr_t)(info.ti_stkHi));
return(result);
}
/* Push the contents of an old object. We treat this as stack */
/* data only because that makes it robust against mark stack */
/* overflow. */
PCR_ERes GC_push_old_obj(void *p, size_t size, PCR_Any data)
{
GC_push_all_stack((ptr_t)p, (ptr_t)p + size);
return(PCR_ERes_okay);
}
extern struct PCR_MM_ProcsRep * GC_old_allocator;
/* defined in pcr_interface.c. */
STATIC void GC_default_push_other_roots(void)
{
/* Traverse data allocated by previous memory managers. */
if ((*(GC_old_allocator->mmp_enumerate))(PCR_Bool_false,
GC_push_old_obj, 0)
!= PCR_ERes_okay) {
ABORT("Old object enumeration failed");
}
/* Traverse all thread stacks. */
if (PCR_ERes_IsErr(
PCR_ThCtl_ApplyToAllOtherThreads(GC_push_thread_stack,0))
|| PCR_ERes_IsErr(GC_push_thread_stack(PCR_Th_CurrThread(), 0))) {
ABORT("Thread stack marking failed");
}
}
# endif /* PCR */
# if defined(GC_PTHREADS) || defined(GC_WIN32_THREADS)
STATIC void GC_default_push_other_roots(void)
{
GC_push_all_stacks();
}
# endif /* GC_WIN32_THREADS || GC_PTHREADS */
# ifdef SN_TARGET_PS3
STATIC void GC_default_push_other_roots(void)
{
ABORT("GC_default_push_other_roots is not implemented");
}
void GC_push_thread_structures(void)
{
ABORT("GC_push_thread_structures is not implemented");
}
# endif /* SN_TARGET_PS3 */
GC_INNER void (*GC_push_other_roots)(void) = GC_default_push_other_roots;
#endif /* THREADS */
/*
* Routines for accessing dirty bits on virtual pages.
* There are six ways to maintain this information:
* DEFAULT_VDB: A simple dummy implementation that treats every page
* as possibly dirty. This makes incremental collection
* useless, but the implementation is still correct.
* MANUAL_VDB: Stacks and static data are always considered dirty.
* Heap pages are considered dirty if GC_dirty(p) has been
* called on some pointer p pointing to somewhere inside
* an object on that page. A GC_dirty() call on a large
* object directly dirties only a single page, but for
* MANUAL_VDB we are careful to treat an object with a dirty
* page as completely dirty.
* In order to avoid races, an object must be marked dirty
* after it is written, and a reference to the object
* must be kept on a stack or in a register in the interim.
* With threads enabled, an object directly reachable from the
* stack at the time of a collection is treated as dirty.
* In single-threaded mode, it suffices to ensure that no
* collection can take place between the pointer assignment
* and the GC_dirty() call.
* PCR_VDB: Use PPCRs virtual dirty bit facility.
* PROC_VDB: Use the /proc facility for reading dirty bits. Only
* works under some SVR4 variants. Even then, it may be
* too slow to be entirely satisfactory. Requires reading
* dirty bits for entire address space. Implementations tend
* to assume that the client is a (slow) debugger.
* MPROTECT_VDB:Protect pages and then catch the faults to keep track of
* dirtied pages. The implementation (and implementability)
* is highly system dependent. This usually fails when system
* calls write to a protected page. We prevent the read system
* call from doing so. It is the clients responsibility to
* make sure that other system calls are similarly protected
* or write only to the stack.
* GWW_VDB: Use the Win32 GetWriteWatch functions, if available, to
* read dirty bits. In case it is not available (because we
* are running on Windows 95, Windows 2000 or earlier),
* MPROTECT_VDB may be defined as a fallback strategy.
*/
#ifndef GC_DISABLE_INCREMENTAL
GC_INNER GC_bool GC_dirty_maintained = FALSE;
#endif
#if defined(PROC_VDB) || defined(GWW_VDB)
/* Add all pages in pht2 to pht1 */
STATIC void GC_or_pages(page_hash_table pht1, page_hash_table pht2)
{
register int i;
for (i = 0; i < PHT_SIZE; i++) pht1[i] |= pht2[i];
}
# ifdef MPROTECT_VDB
STATIC GC_bool GC_gww_page_was_dirty(struct hblk * h)
# else
GC_INNER GC_bool GC_page_was_dirty(struct hblk * h)
# endif
{
register word index;
if (HDR(h) == 0)
return TRUE;
index = PHT_HASH(h);
return get_pht_entry_from_index(GC_grungy_pages, index);
}
# if defined(CHECKSUMS) || defined(PROC_VDB)
/* Used only if GWW_VDB. */
# ifdef MPROTECT_VDB
STATIC GC_bool GC_gww_page_was_ever_dirty(struct hblk * h)
# else
GC_INNER GC_bool GC_page_was_ever_dirty(struct hblk * h)
# endif
{
register word index;
if (HDR(h) == 0)
return TRUE;
index = PHT_HASH(h);
return get_pht_entry_from_index(GC_written_pages, index);
}
# endif /* CHECKSUMS || PROC_VDB */
# ifndef MPROTECT_VDB
/* Ignore write hints. They don't help us here. */
/*ARGSUSED*/
GC_INNER void GC_remove_protection(struct hblk *h, word nblocks,
GC_bool is_ptrfree) {}
# endif
#endif /* PROC_VDB || GWW_VDB */
#ifdef GWW_VDB
# define GC_GWW_BUF_LEN (MAXHINCR * HBLKSIZE / 4096 /* X86 page size */)
/* Still susceptible to overflow, if there are very large allocations, */
/* and everything is dirty. */
static PVOID gww_buf[GC_GWW_BUF_LEN];
# ifdef MPROTECT_VDB
GC_INNER GC_bool GC_gww_dirty_init(void)
{
detect_GetWriteWatch();
return GC_GWW_AVAILABLE();
}
# else
GC_INNER void GC_dirty_init(void)
{
detect_GetWriteWatch();
GC_dirty_maintained = GC_GWW_AVAILABLE();
}
# endif /* !MPROTECT_VDB */
# ifdef MPROTECT_VDB
STATIC void GC_gww_read_dirty(void)
# else
GC_INNER void GC_read_dirty(void)
# endif
{
word i;
BZERO(GC_grungy_pages, sizeof(GC_grungy_pages));
for (i = 0; i != GC_n_heap_sects; ++i) {
GC_ULONG_PTR count;
do {
PVOID * pages, * pages_end;
DWORD page_size;
pages = gww_buf;
count = GC_GWW_BUF_LEN;
/* GetWriteWatch is documented as returning non-zero when it */
/* fails, but the documentation doesn't explicitly say why it */
/* would fail or what its behaviour will be if it fails. */
/* It does appear to fail, at least on recent W2K instances, if */
/* the underlying memory was not allocated with the appropriate */
/* flag. This is common if GC_enable_incremental is called */
/* shortly after GC initialization. To avoid modifying the */
/* interface, we silently work around such a failure, it only */
/* affects the initial (small) heap allocation. If there are */
/* more dirty pages than will fit in the buffer, this is not */
/* treated as a failure; we must check the page count in the */
/* loop condition. Since each partial call will reset the */
/* status of some pages, this should eventually terminate even */
/* in the overflow case. */
if (GetWriteWatch_func(WRITE_WATCH_FLAG_RESET,
GC_heap_sects[i].hs_start,
GC_heap_sects[i].hs_bytes,
pages,
&count,
&page_size) != 0) {
static int warn_count = 0;
unsigned j;
struct hblk * start = (struct hblk *)GC_heap_sects[i].hs_start;
static struct hblk *last_warned = 0;
size_t nblocks = divHBLKSZ(GC_heap_sects[i].hs_bytes);
if ( i != 0 && last_warned != start && warn_count++ < 5) {
last_warned = start;
WARN(
"GC_gww_read_dirty unexpectedly failed at %p: "
"Falling back to marking all pages dirty\n", start);
}
for (j = 0; j < nblocks; ++j) {
word hash = PHT_HASH(start + j);
set_pht_entry_from_index(GC_grungy_pages, hash);
}
count = 1; /* Done with this section. */
} else /* succeeded */ {
pages_end = pages + count;
while (pages != pages_end) {
struct hblk * h = (struct hblk *) *pages++;
struct hblk * h_end = (struct hblk *) ((char *) h + page_size);
do
set_pht_entry_from_index(GC_grungy_pages, PHT_HASH(h));
while (++h < h_end);
}
}
} while (count == GC_GWW_BUF_LEN);
/* FIXME: It's unclear from Microsoft's documentation if this loop */
/* is useful. We suspect the call just fails if the buffer fills */
/* up. But that should still be handled correctly. */
}
GC_or_pages(GC_written_pages, GC_grungy_pages);
}
#endif /* GWW_VDB */
#ifdef DEFAULT_VDB
/* All of the following assume the allocation lock is held. */
/* The client asserts that unallocated pages in the heap are never */
/* written. */
/* Initialize virtual dirty bit implementation. */
GC_INNER void GC_dirty_init(void)
{
if (GC_print_stats == VERBOSE)
GC_log_printf("Initializing DEFAULT_VDB...\n");
GC_dirty_maintained = TRUE;
}
/* Retrieve system dirty bits for heap to a local buffer. */
/* Restore the systems notion of which pages are dirty. */
GC_INNER void GC_read_dirty(void) {}
/* Is the HBLKSIZE sized page at h marked dirty in the local buffer? */
/* If the actual page size is different, this returns TRUE if any */
/* of the pages overlapping h are dirty. This routine may err on the */
/* side of labeling pages as dirty (and this implementation does). */
/*ARGSUSED*/
GC_INNER GC_bool GC_page_was_dirty(struct hblk *h)
{
return(TRUE);
}
/* The following two routines are typically less crucial. */
/* They matter most with large dynamic libraries, or if we can't */
/* accurately identify stacks, e.g. under Solaris 2.X. Otherwise the */
/* following default versions are adequate. */
# ifdef CHECKSUMS
/* Could any valid GC heap pointer ever have been written to this page? */
/*ARGSUSED*/
GC_INNER GC_bool GC_page_was_ever_dirty(struct hblk *h)
{
return(TRUE);
}
# endif /* CHECKSUMS */
/* A call that: */
/* I) hints that [h, h+nblocks) is about to be written. */
/* II) guarantees that protection is removed. */
/* (I) may speed up some dirty bit implementations. */
/* (II) may be essential if we need to ensure that */
/* pointer-free system call buffers in the heap are */
/* not protected. */
/*ARGSUSED*/
GC_INNER void GC_remove_protection(struct hblk *h, word nblocks,
GC_bool is_ptrfree) {}
#endif /* DEFAULT_VDB */
#ifdef MANUAL_VDB
/* Initialize virtual dirty bit implementation. */
GC_INNER void GC_dirty_init(void)
{
if (GC_print_stats == VERBOSE)
GC_log_printf("Initializing MANUAL_VDB...\n");
/* GC_dirty_pages and GC_grungy_pages are already cleared. */
GC_dirty_maintained = TRUE;
}
/* Retrieve system dirty bits for heap to a local buffer. */
/* Restore the systems notion of which pages are dirty. */
GC_INNER void GC_read_dirty(void)
{
BCOPY((word *)GC_dirty_pages, GC_grungy_pages,
(sizeof GC_dirty_pages));
BZERO((word *)GC_dirty_pages, (sizeof GC_dirty_pages));
}
/* Is the HBLKSIZE sized page at h marked dirty in the local buffer? */
/* If the actual page size is different, this returns TRUE if any */
/* of the pages overlapping h are dirty. This routine may err on the */
/* side of labeling pages as dirty (and this implementation does). */
GC_INNER GC_bool GC_page_was_dirty(struct hblk *h)
{
register word index = PHT_HASH(h);
return(HDR(h) == 0 || get_pht_entry_from_index(GC_grungy_pages, index));
}
# define async_set_pht_entry_from_index(db, index) \
set_pht_entry_from_index(db, index) /* for now */
/* Mark the page containing p as dirty. Logically, this dirties the */
/* entire object. */
void GC_dirty(ptr_t p)
{
word index = PHT_HASH(p);
async_set_pht_entry_from_index(GC_dirty_pages, index);
}
/*ARGSUSED*/
GC_INNER void GC_remove_protection(struct hblk *h, word nblocks,
GC_bool is_ptrfree) {}
# ifdef CHECKSUMS
/* Could any valid GC heap pointer ever have been written to this page? */
/*ARGSUSED*/
GC_INNER GC_bool GC_page_was_ever_dirty(struct hblk *h)
{
/* FIXME - implement me. */
return(TRUE);
}
# endif /* CHECKSUMS */
#endif /* MANUAL_VDB */
#ifdef MPROTECT_VDB
/* See DEFAULT_VDB for interface descriptions. */
/*
* This implementation maintains dirty bits itself by catching write
* faults and keeping track of them. We assume nobody else catches
* SIGBUS or SIGSEGV. We assume no write faults occur in system calls.
* This means that clients must ensure that system calls don't write
* to the write-protected heap. Probably the best way to do this is to
* ensure that system calls write at most to POINTERFREE objects in the
* heap, and do even that only if we are on a platform on which those
* are not protected. Another alternative is to wrap system calls
* (see example for read below), but the current implementation holds
* applications.
* We assume the page size is a multiple of HBLKSIZE.
* We prefer them to be the same. We avoid protecting POINTERFREE
* objects only if they are the same.
*/
# ifdef DARWIN
/* Using vm_protect (mach syscall) over mprotect (BSD syscall) seems to
decrease the likelihood of some of the problems described below. */
# include <mach/vm_map.h>
STATIC mach_port_t GC_task_self = 0;
# define PROTECT(addr,len) \
if(vm_protect(GC_task_self,(vm_address_t)(addr),(vm_size_t)(len), \
FALSE, VM_PROT_READ \
| (GC_pages_executable ? VM_PROT_EXECUTE : 0)) \
!= KERN_SUCCESS) { \
ABORT("vm_protect(PROTECT) failed"); \
}
# define UNPROTECT(addr,len) \
if(vm_protect(GC_task_self,(vm_address_t)(addr),(vm_size_t)(len), \
FALSE, (VM_PROT_READ | VM_PROT_WRITE) \
| (GC_pages_executable ? VM_PROT_EXECUTE : 0)) \
!= KERN_SUCCESS) { \
ABORT("vm_protect(UNPROTECT) failed"); \
}
# elif !defined(MSWIN32) && !defined(MSWINCE)
# include <sys/mman.h>
# include <signal.h>
# include <sys/syscall.h>
# define PROTECT(addr, len) \
if (mprotect((caddr_t)(addr), (size_t)(len), \
PROT_READ \
| (GC_pages_executable ? PROT_EXEC : 0)) < 0) { \
ABORT("mprotect failed"); \
}
# define UNPROTECT(addr, len) \
if (mprotect((caddr_t)(addr), (size_t)(len), \
(PROT_READ | PROT_WRITE) \
| (GC_pages_executable ? PROT_EXEC : 0)) < 0) { \
ABORT(GC_pages_executable ? "un-mprotect executable page" \
" failed (probably disabled by OS)" : \
"un-mprotect failed"); \
}
# undef IGNORE_PAGES_EXECUTABLE
# else /* MSWIN32 */
# ifndef MSWINCE
# include <signal.h>
# endif
static DWORD protect_junk;
# define PROTECT(addr, len) \
if (!VirtualProtect((addr), (len), \
GC_pages_executable ? PAGE_EXECUTE_READ : \
PAGE_READONLY, \
&protect_junk)) { \
if (GC_print_stats) \
GC_log_printf("Last error code: 0x%lx\n", (long)GetLastError()); \
ABORT("VirtualProtect failed"); \
}
# define UNPROTECT(addr, len) \
if (!VirtualProtect((addr), (len), \
GC_pages_executable ? PAGE_EXECUTE_READWRITE : \
PAGE_READWRITE, \
&protect_junk)) { \
ABORT("un-VirtualProtect failed"); \
}
# endif /* MSWIN32 || MSWINCE || DARWIN */
# if defined(MSWIN32)
typedef LPTOP_LEVEL_EXCEPTION_FILTER SIG_HNDLR_PTR;
# undef SIG_DFL
# define SIG_DFL (LPTOP_LEVEL_EXCEPTION_FILTER)((signed_word)-1)
# elif defined(MSWINCE)
typedef LONG (WINAPI *SIG_HNDLR_PTR)(struct _EXCEPTION_POINTERS *);
# undef SIG_DFL
# define SIG_DFL (SIG_HNDLR_PTR) (-1)
# elif defined(DARWIN)
typedef void (* SIG_HNDLR_PTR)();
# else
typedef void (* SIG_HNDLR_PTR)(int, siginfo_t *, void *);
typedef void (* PLAIN_HNDLR_PTR)(int);
# endif
# if defined(__GLIBC__)
# if __GLIBC__ < 2 || __GLIBC__ == 2 && __GLIBC_MINOR__ < 2
# error glibc too old?
# endif
# endif
#ifndef DARWIN
STATIC SIG_HNDLR_PTR GC_old_segv_handler = 0;
/* Also old MSWIN32 ACCESS_VIOLATION filter */
# if !defined(MSWIN32) && !defined(MSWINCE)
STATIC SIG_HNDLR_PTR GC_old_bus_handler = 0;
STATIC GC_bool GC_old_bus_handler_used_si = FALSE;
STATIC GC_bool GC_old_segv_handler_used_si = FALSE;
# endif
#endif /* !DARWIN */
#if defined(THREADS)
/* We need to lock around the bitmap update in the write fault handler */
/* in order to avoid the risk of losing a bit. We do this with a */
/* test-and-set spin lock if we know how to do that. Otherwise we */
/* check whether we are already in the handler and use the dumb but */
/* safe fallback algorithm of setting all bits in the word. */
/* Contention should be very rare, so we do the minimum to handle it */
/* correctly. */
#ifdef AO_HAVE_test_and_set_acquire
GC_INNER volatile AO_TS_t GC_fault_handler_lock = AO_TS_INITIALIZER;
static void async_set_pht_entry_from_index(volatile page_hash_table db,
size_t index)
{
while (AO_test_and_set_acquire(&GC_fault_handler_lock) == AO_TS_SET) {
/* empty */
}
/* Could also revert to set_pht_entry_from_index_safe if initial */
/* GC_test_and_set fails. */
set_pht_entry_from_index(db, index);
AO_CLEAR(&GC_fault_handler_lock);
}
#else /* !AO_HAVE_test_and_set_acquire */
# error No test_and_set operation: Introduces a race.
/* THIS WOULD BE INCORRECT! */
/* The dirty bit vector may be temporarily wrong, */
/* just before we notice the conflict and correct it. We may end up */
/* looking at it while it's wrong. But this requires contention */
/* exactly when a GC is triggered, which seems far less likely to */
/* fail than the old code, which had no reported failures. Thus we */
/* leave it this way while we think of something better, or support */
/* GC_test_and_set on the remaining platforms. */
static volatile word currently_updating = 0;
static void async_set_pht_entry_from_index(volatile page_hash_table db,
size_t index)
{
unsigned int update_dummy;
currently_updating = (word)(&update_dummy);
set_pht_entry_from_index(db, index);
/* If we get contention in the 10 or so instruction window here, */
/* and we get stopped by a GC between the two updates, we lose! */
if (currently_updating != (word)(&update_dummy)) {
set_pht_entry_from_index_safe(db, index);
/* We claim that if two threads concurrently try to update the */
/* dirty bit vector, the first one to execute UPDATE_START */
/* will see it changed when UPDATE_END is executed. (Note that */
/* &update_dummy must differ in two distinct threads.) It */
/* will then execute set_pht_entry_from_index_safe, thus */
/* returning us to a safe state, though not soon enough. */
}
}
#endif /* !AO_HAVE_test_and_set_acquire */
#else /* !THREADS */
# define async_set_pht_entry_from_index(db, index) \
set_pht_entry_from_index(db, index)
#endif /* !THREADS */
#ifdef CHECKSUMS
void GC_record_fault(struct hblk * h); /* from checksums.c */
#endif
#ifndef DARWIN
# if !defined(MSWIN32) && !defined(MSWINCE)
# include <errno.h>
# if defined(FREEBSD) || defined(HURD) || defined(HPUX)
# define SIG_OK (sig == SIGBUS || sig == SIGSEGV)
# else
# define SIG_OK (sig == SIGSEGV)
# endif
# if defined(FREEBSD)
# ifndef SEGV_ACCERR
# define SEGV_ACCERR 2
# endif
# define CODE_OK (si -> si_code == BUS_PAGE_FAULT \
|| si -> si_code == SEGV_ACCERR)
# elif defined(OSF1)
# define CODE_OK (si -> si_code == 2 /* experimentally determined */)
# elif defined(IRIX5)
# define CODE_OK (si -> si_code == EACCES)
# elif defined(HURD)
# define CODE_OK TRUE
# elif defined(LINUX)
# define CODE_OK TRUE
/* Empirically c.trapno == 14, on IA32, but is that useful? */
/* Should probably consider alignment issues on other */
/* architectures. */
# elif defined(HPUX)
# define CODE_OK (si -> si_code == SEGV_ACCERR \
|| si -> si_code == BUS_ADRERR \
|| si -> si_code == BUS_UNKNOWN \
|| si -> si_code == SEGV_UNKNOWN \
|| si -> si_code == BUS_OBJERR)
# elif defined(SUNOS5SIGS)
# define CODE_OK (si -> si_code == SEGV_ACCERR)
# endif
# ifndef NO_GETCONTEXT
# include <ucontext.h>
# endif
/*ARGSUSED*/
STATIC void GC_write_fault_handler(int sig, siginfo_t *si, void *raw_sc)
# else
# define SIG_OK (exc_info -> ExceptionRecord -> ExceptionCode \
== STATUS_ACCESS_VIOLATION)
# define CODE_OK (exc_info -> ExceptionRecord -> ExceptionInformation[0] \
== 1) /* Write fault */
STATIC LONG WINAPI GC_write_fault_handler(
struct _EXCEPTION_POINTERS *exc_info)
# endif /* MSWIN32 || MSWINCE */
{
# if !defined(MSWIN32) && !defined(MSWINCE)
char *addr = si -> si_addr;
# else
char * addr = (char *) (exc_info -> ExceptionRecord
-> ExceptionInformation[1]);
# endif
unsigned i;
if (SIG_OK && CODE_OK) {
register struct hblk * h =
(struct hblk *)((word)addr & ~(GC_page_size-1));
GC_bool in_allocd_block;
# ifdef CHECKSUMS
GC_record_fault(h);
# endif
# ifdef SUNOS5SIGS
/* Address is only within the correct physical page. */
in_allocd_block = FALSE;
for (i = 0; i < divHBLKSZ(GC_page_size); i++) {
if (HDR(h+i) != 0) {
in_allocd_block = TRUE;
break;
}
}
# else
in_allocd_block = (HDR(addr) != 0);
# endif
if (!in_allocd_block) {
/* FIXME - We should make sure that we invoke the */
/* old handler with the appropriate calling */
/* sequence, which often depends on SA_SIGINFO. */
/* Heap blocks now begin and end on page boundaries */
SIG_HNDLR_PTR old_handler;
# if defined(MSWIN32) || defined(MSWINCE)
old_handler = GC_old_segv_handler;
# else
GC_bool used_si;
if (sig == SIGSEGV) {
old_handler = GC_old_segv_handler;
used_si = GC_old_segv_handler_used_si;
} else {
old_handler = GC_old_bus_handler;
used_si = GC_old_bus_handler_used_si;
}
# endif
if (old_handler == (SIG_HNDLR_PTR)SIG_DFL) {
# if !defined(MSWIN32) && !defined(MSWINCE)
if (GC_print_stats)
GC_log_printf("Unexpected segfault at %p\n", addr);
ABORT("Unexpected bus error or segmentation fault");
# else
return(EXCEPTION_CONTINUE_SEARCH);
# endif
} else {
/*
* FIXME: This code should probably check if the
* old signal handler used the traditional style and
* if so call it using that style.
*/
# if defined(MSWIN32) || defined(MSWINCE)
return((*old_handler)(exc_info));
# else
if (used_si)
((SIG_HNDLR_PTR)old_handler) (sig, si, raw_sc);
else
/* FIXME: should pass nonstandard args as well. */
((PLAIN_HNDLR_PTR)old_handler) (sig);
return;
# endif
}
}
UNPROTECT(h, GC_page_size);
/* We need to make sure that no collection occurs between */
/* the UNPROTECT and the setting of the dirty bit. Otherwise */
/* a write by a third thread might go unnoticed. Reversing */
/* the order is just as bad, since we would end up unprotecting */
/* a page in a GC cycle during which it's not marked. */
/* Currently we do this by disabling the thread stopping */
/* signals while this handler is running. An alternative might */
/* be to record the fact that we're about to unprotect, or */
/* have just unprotected a page in the GC's thread structure, */
/* and then to have the thread stopping code set the dirty */
/* flag, if necessary. */
for (i = 0; i < divHBLKSZ(GC_page_size); i++) {
size_t index = PHT_HASH(h+i);
async_set_pht_entry_from_index(GC_dirty_pages, index);
}
/* The write may not take place before dirty bits are read. */
/* But then we'll fault again ... */
# if defined(MSWIN32) || defined(MSWINCE)
return(EXCEPTION_CONTINUE_EXECUTION);
# else
return;
# endif
}
# if defined(MSWIN32) || defined(MSWINCE)
return EXCEPTION_CONTINUE_SEARCH;
# else
if (GC_print_stats)
GC_log_printf("Unexpected segfault at %p\n", addr);
ABORT("Unexpected bus error or segmentation fault");
# endif
}
# ifdef GC_WIN32_THREADS
GC_INNER void GC_set_write_fault_handler(void)
{
SetUnhandledExceptionFilter(GC_write_fault_handler);
}
# endif
#endif /* !DARWIN */
/* We hold the allocation lock. We expect block h to be written */
/* shortly. Ensure that all pages containing any part of the n hblks */
/* starting at h are no longer protected. If is_ptrfree is false, also */
/* ensure that they will subsequently appear to be dirty. Not allowed */
/* to call GC_printf (and the friends) here, see Win32 GC_stop_world() */
/* for the information. */
GC_INNER void GC_remove_protection(struct hblk *h, word nblocks,
GC_bool is_ptrfree)
{
struct hblk * h_trunc; /* Truncated to page boundary */
struct hblk * h_end; /* Page boundary following block end */
struct hblk * current;
# if defined(GWW_VDB)
if (GC_GWW_AVAILABLE()) return;
# endif
if (!GC_dirty_maintained) return;
h_trunc = (struct hblk *)((word)h & ~(GC_page_size-1));
h_end = (struct hblk *)(((word)(h + nblocks) + GC_page_size-1)
& ~(GC_page_size-1));
if (h_end == h_trunc + 1 &&
get_pht_entry_from_index(GC_dirty_pages, PHT_HASH(h_trunc))) {
/* already marked dirty, and hence unprotected. */
return;
}
for (current = h_trunc; current < h_end; ++current) {
size_t index = PHT_HASH(current);
if (!is_ptrfree || current < h || current >= h + nblocks) {
async_set_pht_entry_from_index(GC_dirty_pages, index);
}
}
UNPROTECT(h_trunc, (ptr_t)h_end - (ptr_t)h_trunc);
}
#if !defined(DARWIN)
GC_INNER void GC_dirty_init(void)
{
# if !defined(MSWIN32) && !defined(MSWINCE)
struct sigaction act, oldact;
act.sa_flags = SA_RESTART | SA_SIGINFO;
act.sa_sigaction = GC_write_fault_handler;
(void)sigemptyset(&act.sa_mask);
# ifdef SIG_SUSPEND
/* Arrange to postpone SIG_SUSPEND while we're in a write fault */
/* handler. This effectively makes the handler atomic w.r.t. */
/* stopping the world for GC. */
(void)sigaddset(&act.sa_mask, SIG_SUSPEND);
# endif /* SIG_SUSPEND */
# endif
if (GC_print_stats == VERBOSE)
GC_log_printf(
"Initializing mprotect virtual dirty bit implementation\n");
GC_dirty_maintained = TRUE;
if (GC_page_size % HBLKSIZE != 0) {
ABORT("Page size not multiple of HBLKSIZE");
}
# if !defined(MSWIN32) && !defined(MSWINCE)
# if defined(GC_IRIX_THREADS)
sigaction(SIGSEGV, 0, &oldact);
sigaction(SIGSEGV, &act, 0);
# else
{
int res = sigaction(SIGSEGV, &act, &oldact);
if (res != 0) ABORT("Sigaction failed");
}
# endif
if (oldact.sa_flags & SA_SIGINFO) {
GC_old_segv_handler = oldact.sa_sigaction;
GC_old_segv_handler_used_si = TRUE;
} else {
GC_old_segv_handler = (SIG_HNDLR_PTR)oldact.sa_handler;
GC_old_segv_handler_used_si = FALSE;
}
if (GC_old_segv_handler == (SIG_HNDLR_PTR)SIG_IGN) {
if (GC_print_stats)
GC_err_printf("Previously ignored segmentation violation!?\n");
GC_old_segv_handler = (SIG_HNDLR_PTR)SIG_DFL;
}
if (GC_old_segv_handler != (SIG_HNDLR_PTR)SIG_DFL) {
if (GC_print_stats == VERBOSE)
GC_log_printf("Replaced other SIGSEGV handler\n");
}
# if defined(HPUX) || defined(LINUX) || defined(HURD) \
|| (defined(FREEBSD) && defined(SUNOS5SIGS))
sigaction(SIGBUS, &act, &oldact);
if (oldact.sa_flags & SA_SIGINFO) {
GC_old_bus_handler = oldact.sa_sigaction;
GC_old_bus_handler_used_si = TRUE;
} else {
GC_old_bus_handler = (SIG_HNDLR_PTR)oldact.sa_handler;
GC_old_bus_handler_used_si = FALSE;
}
if (GC_old_bus_handler == (SIG_HNDLR_PTR)SIG_IGN) {
if (GC_print_stats)
GC_err_printf("Previously ignored bus error!?\n");
GC_old_bus_handler = (SIG_HNDLR_PTR)SIG_DFL;
}
if (GC_old_bus_handler != (SIG_HNDLR_PTR)SIG_DFL) {
if (GC_print_stats == VERBOSE)
GC_log_printf("Replaced other SIGBUS handler\n");
}
# endif /* HPUX || LINUX || HURD || (FREEBSD && SUNOS5SIGS) */
# endif /* ! MS windows */
# if defined(GWW_VDB)
if (GC_gww_dirty_init())
return;
# endif
# if defined(MSWIN32)
GC_old_segv_handler = SetUnhandledExceptionFilter(GC_write_fault_handler);
if (GC_old_segv_handler != NULL) {
if (GC_print_stats)
GC_log_printf("Replaced other UnhandledExceptionFilter\n");
} else {
GC_old_segv_handler = SIG_DFL;
}
# elif defined(MSWINCE)
/* MPROTECT_VDB is unsupported for WinCE at present. */
/* FIXME: implement it (if possible). */
# endif
}
#endif /* !DARWIN */
GC_API int GC_CALL GC_incremental_protection_needs(void)
{
if (GC_page_size == HBLKSIZE) {
return GC_PROTECTS_POINTER_HEAP;
} else {
return GC_PROTECTS_POINTER_HEAP | GC_PROTECTS_PTRFREE_HEAP;
}
}
#define HAVE_INCREMENTAL_PROTECTION_NEEDS
#define IS_PTRFREE(hhdr) ((hhdr)->hb_descr == 0)
#define PAGE_ALIGNED(x) !((word)(x) & (GC_page_size - 1))
STATIC void GC_protect_heap(void)
{
ptr_t start;
size_t len;
struct hblk * current;
struct hblk * current_start; /* Start of block to be protected. */
struct hblk * limit;
unsigned i;
GC_bool protect_all =
(0 != (GC_incremental_protection_needs() & GC_PROTECTS_PTRFREE_HEAP));
for (i = 0; i < GC_n_heap_sects; i++) {
start = GC_heap_sects[i].hs_start;
len = GC_heap_sects[i].hs_bytes;
if (protect_all) {
PROTECT(start, len);
} else {
GC_ASSERT(PAGE_ALIGNED(len))
GC_ASSERT(PAGE_ALIGNED(start))
current_start = current = (struct hblk *)start;
limit = (struct hblk *)(start + len);
while (current < limit) {
hdr * hhdr;
word nhblks;
GC_bool is_ptrfree;
GC_ASSERT(PAGE_ALIGNED(current));
GET_HDR(current, hhdr);
if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
/* This can happen only if we're at the beginning of a */
/* heap segment, and a block spans heap segments. */
/* We will handle that block as part of the preceding */
/* segment. */
GC_ASSERT(current_start == current);
current_start = ++current;
continue;
}
if (HBLK_IS_FREE(hhdr)) {
GC_ASSERT(PAGE_ALIGNED(hhdr -> hb_sz));
nhblks = divHBLKSZ(hhdr -> hb_sz);
is_ptrfree = TRUE; /* dirty on alloc */
} else {
nhblks = OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
is_ptrfree = IS_PTRFREE(hhdr);
}
if (is_ptrfree) {
if (current_start < current) {
PROTECT(current_start, (ptr_t)current - (ptr_t)current_start);
}
current_start = (current += nhblks);
} else {
current += nhblks;
}
}
if (current_start < current) {
PROTECT(current_start, (ptr_t)current - (ptr_t)current_start);
}
}
}
}
/* We assume that either the world is stopped or its OK to lose dirty */
/* bits while this is happenning (as in GC_enable_incremental). */
GC_INNER void GC_read_dirty(void)
{
# if defined(GWW_VDB)
if (GC_GWW_AVAILABLE()) {
GC_gww_read_dirty();
return;
}
# endif
BCOPY((word *)GC_dirty_pages, GC_grungy_pages,
(sizeof GC_dirty_pages));
BZERO((word *)GC_dirty_pages, (sizeof GC_dirty_pages));
GC_protect_heap();
}
GC_INNER GC_bool GC_page_was_dirty(struct hblk *h)
{
register word index;
# if defined(GWW_VDB)
if (GC_GWW_AVAILABLE())
return GC_gww_page_was_dirty(h);
# endif
index = PHT_HASH(h);
return(HDR(h) == 0 || get_pht_entry_from_index(GC_grungy_pages, index));
}
/*
* Acquiring the allocation lock here is dangerous, since this
* can be called from within GC_call_with_alloc_lock, and the cord
* package does so. On systems that allow nested lock acquisition, this
* happens to work.
* On other systems, SET_LOCK_HOLDER and friends must be suitably defined.
*/
#if 0
static GC_bool syscall_acquired_lock = FALSE; /* Protected by GC lock. */
void GC_begin_syscall(void)
{
/* FIXME: Resurrecting this code would require fixing the */
/* test, which can spuriously return TRUE. */
if (!I_HOLD_LOCK()) {
LOCK();
syscall_acquired_lock = TRUE;
}
}
void GC_end_syscall(void)
{
if (syscall_acquired_lock) {
syscall_acquired_lock = FALSE;
UNLOCK();
}
}
void GC_unprotect_range(ptr_t addr, word len)
{
struct hblk * start_block;
struct hblk * end_block;
register struct hblk *h;
ptr_t obj_start;
if (!GC_dirty_maintained) return;
obj_start = GC_base(addr);
if (obj_start == 0) return;
if (GC_base(addr + len - 1) != obj_start) {
ABORT("GC_unprotect_range(range bigger than object)");
}
start_block = (struct hblk *)((word)addr & ~(GC_page_size - 1));
end_block = (struct hblk *)((word)(addr + len - 1) & ~(GC_page_size - 1));
end_block += GC_page_size/HBLKSIZE - 1;
for (h = start_block; h <= end_block; h++) {
register word index = PHT_HASH(h);
async_set_pht_entry_from_index(GC_dirty_pages, index);
}
UNPROTECT(start_block,
((ptr_t)end_block - (ptr_t)start_block) + HBLKSIZE);
}
/* We no longer wrap read by default, since that was causing too many */
/* problems. It is preferred that the client instead avoids writing */
/* to the write-protected heap with a system call. */
/* This still serves as sample code if you do want to wrap system calls.*/
#if !defined(MSWIN32) && !defined(MSWINCE) && !defined(GC_USE_LD_WRAP)
/* Replacement for UNIX system call. */
/* Other calls that write to the heap should be handled similarly. */
/* Note that this doesn't work well for blocking reads: It will hold */
/* the allocation lock for the entire duration of the call. Multithreaded */
/* clients should really ensure that it won't block, either by setting */
/* the descriptor nonblocking, or by calling select or poll first, to */
/* make sure that input is available. */
/* Another, preferred alternative is to ensure that system calls never */
/* write to the protected heap (see above). */
# include <unistd.h>
# include <sys/uio.h>
ssize_t read(int fd, void *buf, size_t nbyte)
{
int result;
GC_begin_syscall();
GC_unprotect_range(buf, (word)nbyte);
# if defined(IRIX5) || defined(GC_LINUX_THREADS)
/* Indirect system call may not always be easily available. */
/* We could call _read, but that would interfere with the */
/* libpthread interception of read. */
/* On Linux, we have to be careful with the linuxthreads */
/* read interception. */
{
struct iovec iov;
iov.iov_base = buf;
iov.iov_len = nbyte;
result = readv(fd, &iov, 1);
}
# else
# if defined(HURD)
result = __read(fd, buf, nbyte);
# else
/* The two zero args at the end of this list are because one
IA-64 syscall() implementation actually requires six args
to be passed, even though they aren't always used. */
result = syscall(SYS_read, fd, buf, nbyte, 0, 0);
# endif /* !HURD */
# endif
GC_end_syscall();
return(result);
}
#endif /* !MSWIN32 && !MSWINCE && !GC_LINUX_THREADS */
#if defined(GC_USE_LD_WRAP) && !defined(THREADS)
/* We use the GNU ld call wrapping facility. */
/* I'm not sure that this actually wraps whatever version of read */
/* is called by stdio. That code also mentions __read. */
# include <unistd.h>
ssize_t __wrap_read(int fd, void *buf, size_t nbyte)
{
int result;
GC_begin_syscall();
GC_unprotect_range(buf, (word)nbyte);
result = __real_read(fd, buf, nbyte);
GC_end_syscall();
return(result);
}
/* We should probably also do this for __read, or whatever stdio */
/* actually calls. */
#endif
#endif /* 0 */
# ifdef CHECKSUMS
/*ARGSUSED*/
GC_INNER GC_bool GC_page_was_ever_dirty(struct hblk *h)
{
# if defined(GWW_VDB)
if (GC_GWW_AVAILABLE())
return GC_gww_page_was_ever_dirty(h);
# endif
return(TRUE);
}
# endif /* CHECKSUMS */
#endif /* MPROTECT_VDB */
#ifdef PROC_VDB
/* See DEFAULT_VDB for interface descriptions. */
/* This implementation assumes a Solaris 2.X like /proc */
/* pseudo-file-system from which we can read page modified bits. This */
/* facility is far from optimal (e.g. we would like to get the info for */
/* only some of the address space), but it avoids intercepting system */
/* calls. */
# include <errno.h>
# include <sys/types.h>
# include <sys/signal.h>
# include <sys/fault.h>
# include <sys/syscall.h>
# include <sys/procfs.h>
# include <sys/stat.h>
# define INITIAL_BUF_SZ 16384
STATIC word GC_proc_buf_size = INITIAL_BUF_SZ;
STATIC char *GC_proc_buf = NULL;
STATIC int GC_proc_fd = 0;
GC_INNER void GC_dirty_init(void)
{
int fd;
char buf[30];
if (GC_bytes_allocd != 0 || GC_bytes_allocd_before_gc != 0) {
memset(GC_written_pages, 0xff, sizeof(page_hash_table));
if (GC_print_stats == VERBOSE)
GC_log_printf("Allocated bytes:%lu:all pages may have been written\n",
(unsigned long)(GC_bytes_allocd
+ GC_bytes_allocd_before_gc));
}
sprintf(buf, "/proc/%ld", (long)getpid());
fd = open(buf, O_RDONLY);
if (fd < 0) {
ABORT("/proc open failed");
}
GC_proc_fd = syscall(SYS_ioctl, fd, PIOCOPENPD, 0);
close(fd);
syscall(SYS_fcntl, GC_proc_fd, F_SETFD, FD_CLOEXEC);
if (GC_proc_fd < 0) {
WARN("/proc ioctl(PIOCOPENPD) failed", 0);
return;
}
GC_dirty_maintained = TRUE;
GC_proc_buf = GC_scratch_alloc(GC_proc_buf_size);
}
# define READ read
GC_INNER void GC_read_dirty(void)
{
int nmaps;
unsigned long npages;
unsigned pagesize;
ptr_t vaddr, limit;
struct prasmap * map;
char * bufp;
int i;
BZERO(GC_grungy_pages, sizeof(GC_grungy_pages));
bufp = GC_proc_buf;
if (READ(GC_proc_fd, bufp, GC_proc_buf_size) <= 0) {
/* Retry with larger buffer. */
word new_size = 2 * GC_proc_buf_size;
char *new_buf;
if (GC_print_stats)
GC_err_printf("/proc read failed: GC_proc_buf_size = %lu\n",
(unsigned long)GC_proc_buf_size);
new_buf = GC_scratch_alloc(new_size);
if (new_buf != 0) {
GC_proc_buf = bufp = new_buf;
GC_proc_buf_size = new_size;
}
if (READ(GC_proc_fd, bufp, GC_proc_buf_size) <= 0) {
WARN("Insufficient space for /proc read\n", 0);
/* Punt: */
memset(GC_grungy_pages, 0xff, sizeof (page_hash_table));
memset(GC_written_pages, 0xff, sizeof(page_hash_table));
return;
}
}
/* Copy dirty bits into GC_grungy_pages */
nmaps = ((struct prpageheader *)bufp) -> pr_nmap;
# ifdef DEBUG_DIRTY_BITS
GC_log_printf("Proc VDB read: pr_nmap= %u, pr_npage= %lu\n",
nmaps, ((struct prpageheader *)bufp)->pr_npage);
# endif
bufp += sizeof(struct prpageheader);
for (i = 0; i < nmaps; i++) {
map = (struct prasmap *)bufp;
vaddr = (ptr_t)(map -> pr_vaddr);
npages = map -> pr_npage;
pagesize = map -> pr_pagesize;
# ifdef DEBUG_DIRTY_BITS
GC_log_printf(
"pr_vaddr= %p, npage= %lu, mflags= 0x%x, pagesize= 0x%x\n",
vaddr, npages, map->pr_mflags, pagesize);
# endif
bufp += sizeof(struct prasmap);
limit = vaddr + pagesize * npages;
for (; vaddr < limit; vaddr += pagesize) {
if ((*bufp++) & PG_MODIFIED) {
register struct hblk * h;
ptr_t next_vaddr = vaddr + pagesize;
# ifdef DEBUG_DIRTY_BITS
GC_log_printf("dirty page at: %p\n", vaddr);
# endif
for (h = (struct hblk *)vaddr; (ptr_t)h < next_vaddr; h++) {
register word index = PHT_HASH(h);
set_pht_entry_from_index(GC_grungy_pages, index);
}
}
}
bufp = (char *)(((word)bufp + (sizeof(long)-1)) & ~(sizeof(long)-1));
}
# ifdef DEBUG_DIRTY_BITS
GC_log_printf("Proc VDB read done.\n");
# endif
/* Update GC_written_pages. */
GC_or_pages(GC_written_pages, GC_grungy_pages);
}
# undef READ
#endif /* PROC_VDB */
#ifdef PCR_VDB
# include "vd/PCR_VD.h"
# define NPAGES (32*1024) /* 128 MB */
PCR_VD_DB GC_grungy_bits[NPAGES];
STATIC ptr_t GC_vd_base = NULL;
/* Address corresponding to GC_grungy_bits[0] */
/* HBLKSIZE aligned. */
GC_INNER void GC_dirty_init(void)
{
GC_dirty_maintained = TRUE;
/* For the time being, we assume the heap generally grows up */
GC_vd_base = GC_heap_sects[0].hs_start;
if (GC_vd_base == 0) {
ABORT("Bad initial heap segment");
}
if (PCR_VD_Start(HBLKSIZE, GC_vd_base, NPAGES*HBLKSIZE)
!= PCR_ERes_okay) {
ABORT("Dirty bit initialization failed");
}
}
GC_INNER void GC_read_dirty(void)
{
/* lazily enable dirty bits on newly added heap sects */
{
static int onhs = 0;
int nhs = GC_n_heap_sects;
for(; onhs < nhs; onhs++) {
PCR_VD_WriteProtectEnable(
GC_heap_sects[onhs].hs_start,
GC_heap_sects[onhs].hs_bytes );
}
}
if (PCR_VD_Clear(GC_vd_base, NPAGES*HBLKSIZE, GC_grungy_bits)
!= PCR_ERes_okay) {
ABORT("Dirty bit read failed");
}
}
GC_INNER GC_bool GC_page_was_dirty(struct hblk *h)
{
if((ptr_t)h < GC_vd_base || (ptr_t)h >= GC_vd_base + NPAGES*HBLKSIZE) {
return(TRUE);
}
return(GC_grungy_bits[h - (struct hblk *)GC_vd_base] & PCR_VD_DB_dirtyBit);
}
/*ARGSUSED*/
GC_INNER void GC_remove_protection(struct hblk *h, word nblocks,
GC_bool is_ptrfree)
{
PCR_VD_WriteProtectDisable(h, nblocks*HBLKSIZE);
PCR_VD_WriteProtectEnable(h, nblocks*HBLKSIZE);
}
#endif /* PCR_VDB */
#if defined(MPROTECT_VDB) && defined(DARWIN)
/* The following sources were used as a "reference" for this exception
handling code:
1. Apple's mach/xnu documentation
2. Timothy J. Wood's "Mach Exception Handlers 101" post to the
omnigroup's macosx-dev list.
www.omnigroup.com/mailman/archive/macosx-dev/2000-June/014178.html
3. macosx-nat.c from Apple's GDB source code.
*/
/* The bug that caused all this trouble should now be fixed. This should
eventually be removed if all goes well. */
/* #define BROKEN_EXCEPTION_HANDLING */
#include <mach/mach.h>
#include <mach/mach_error.h>
#include <mach/thread_status.h>
#include <mach/exception.h>
#include <mach/task.h>
#include <pthread.h>
/* These are not defined in any header, although they are documented */
extern boolean_t
exc_server(mach_msg_header_t *, mach_msg_header_t *);
extern kern_return_t
exception_raise(mach_port_t, mach_port_t, mach_port_t, exception_type_t,
exception_data_t, mach_msg_type_number_t);
extern kern_return_t
exception_raise_state(mach_port_t, mach_port_t, mach_port_t, exception_type_t,
exception_data_t, mach_msg_type_number_t,
thread_state_flavor_t*, thread_state_t,
mach_msg_type_number_t, thread_state_t,
mach_msg_type_number_t*);
extern kern_return_t
exception_raise_state_identity(mach_port_t, mach_port_t, mach_port_t,
exception_type_t, exception_data_t,
mach_msg_type_number_t, thread_state_flavor_t*,
thread_state_t, mach_msg_type_number_t,
thread_state_t, mach_msg_type_number_t*);
GC_API_OSCALL kern_return_t
catch_exception_raise(mach_port_t exception_port, mach_port_t thread,
mach_port_t task, exception_type_t exception,
exception_data_t code, mach_msg_type_number_t code_count);
/* These should never be called, but just in case... */
GC_API_OSCALL kern_return_t
catch_exception_raise_state(mach_port_name_t exception_port, int exception,
exception_data_t code,
mach_msg_type_number_t codeCnt, int flavor,
thread_state_t old_state, int old_stateCnt,
thread_state_t new_state, int new_stateCnt)
{
ABORT("Unexpected catch_exception_raise_state invocation");
return(KERN_INVALID_ARGUMENT);
}
GC_API_OSCALL kern_return_t
catch_exception_raise_state_identity(mach_port_name_t exception_port,
mach_port_t thread, mach_port_t task,
int exception, exception_data_t code,
mach_msg_type_number_t codeCnt, int flavor,
thread_state_t old_state, int old_stateCnt,
thread_state_t new_state, int new_stateCnt)
{
ABORT("Unexpected catch_exception_raise_state_identity invocation");
return(KERN_INVALID_ARGUMENT);
}
#define MAX_EXCEPTION_PORTS 16
static struct {
mach_msg_type_number_t count;
exception_mask_t masks[MAX_EXCEPTION_PORTS];
exception_handler_t ports[MAX_EXCEPTION_PORTS];
exception_behavior_t behaviors[MAX_EXCEPTION_PORTS];
thread_state_flavor_t flavors[MAX_EXCEPTION_PORTS];
} GC_old_exc_ports;
STATIC struct {
void (*volatile os_callback[3])(void);
mach_port_t exception;
# if defined(THREADS)
mach_port_t reply;
# endif
} GC_ports = {
{
/* This is to prevent stripping these routines as dead. */
(void (*)(void))catch_exception_raise,
(void (*)(void))catch_exception_raise_state,
(void (*)(void))catch_exception_raise_state_identity
},
0
};
typedef struct {
mach_msg_header_t head;
} GC_msg_t;
typedef enum {
GC_MP_NORMAL,
GC_MP_DISCARDING,
GC_MP_STOPPED
} GC_mprotect_state_t;
#ifdef THREADS
/* FIXME: 1 and 2 seem to be safe to use in the msgh_id field, */
/* but it isn't documented. Use the source and see if they */
/* should be ok. */
# define ID_STOP 1
# define ID_RESUME 2
/* This value is only used on the reply port. */
# define ID_ACK 3
STATIC GC_mprotect_state_t GC_mprotect_state = 0;
/* The following should ONLY be called when the world is stopped. */
STATIC void GC_mprotect_thread_notify(mach_msg_id_t id)
{
struct {
GC_msg_t msg;
mach_msg_trailer_t trailer;
} buf;
mach_msg_return_t r;
/* remote, local */
buf.msg.head.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND, 0);
buf.msg.head.msgh_size = sizeof(buf.msg);
buf.msg.head.msgh_remote_port = GC_ports.exception;
buf.msg.head.msgh_local_port = MACH_PORT_NULL;
buf.msg.head.msgh_id = id;
r = mach_msg(&buf.msg.head, MACH_SEND_MSG | MACH_RCV_MSG | MACH_RCV_LARGE,
sizeof(buf.msg), sizeof(buf), GC_ports.reply,
MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
if (r != MACH_MSG_SUCCESS)
ABORT("mach_msg failed in GC_mprotect_thread_notify");
if (buf.msg.head.msgh_id != ID_ACK)
ABORT("Invalid ack in GC_mprotect_thread_notify");
}
/* Should only be called by the mprotect thread */
STATIC void GC_mprotect_thread_reply(void)
{
GC_msg_t msg;
mach_msg_return_t r;
/* remote, local */
msg.head.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND, 0);
msg.head.msgh_size = sizeof(msg);
msg.head.msgh_remote_port = GC_ports.reply;
msg.head.msgh_local_port = MACH_PORT_NULL;
msg.head.msgh_id = ID_ACK;
r = mach_msg(&msg.head, MACH_SEND_MSG, sizeof(msg), 0, MACH_PORT_NULL,
MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
if (r != MACH_MSG_SUCCESS)
ABORT("mach_msg failed in GC_mprotect_thread_reply");
}
GC_INNER void GC_mprotect_stop(void)
{
GC_mprotect_thread_notify(ID_STOP);
}
GC_INNER void GC_mprotect_resume(void)
{
GC_mprotect_thread_notify(ID_RESUME);
}
# ifndef GC_NO_THREADS_DISCOVERY
GC_INNER void GC_darwin_register_mach_handler_thread(mach_port_t thread);
# endif
#else
/* The compiler should optimize away any GC_mprotect_state computations */
# define GC_mprotect_state GC_MP_NORMAL
#endif /* !THREADS */
STATIC void *GC_mprotect_thread(void *arg)
{
mach_msg_return_t r;
/* These two structures contain some private kernel data. We don't */
/* need to access any of it so we don't bother defining a proper */
/* struct. The correct definitions are in the xnu source code. */
struct {
mach_msg_header_t head;
char data[256];
} reply;
struct {
mach_msg_header_t head;
mach_msg_body_t msgh_body;
char data[1024];
} msg;
mach_msg_id_t id;
# if defined(THREADS) && !defined(GC_NO_THREADS_DISCOVERY)
GC_darwin_register_mach_handler_thread(mach_thread_self());
# endif
for(;;) {
r = mach_msg(&msg.head, MACH_RCV_MSG | MACH_RCV_LARGE |
(GC_mprotect_state == GC_MP_DISCARDING ? MACH_RCV_TIMEOUT : 0),
0, sizeof(msg), GC_ports.exception,
GC_mprotect_state == GC_MP_DISCARDING ? 0
: MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
id = r == MACH_MSG_SUCCESS ? msg.head.msgh_id : -1;
# if defined(THREADS)
if(GC_mprotect_state == GC_MP_DISCARDING) {
if(r == MACH_RCV_TIMED_OUT) {
GC_mprotect_state = GC_MP_STOPPED;
GC_mprotect_thread_reply();
continue;
}
if(r == MACH_MSG_SUCCESS && (id == ID_STOP || id == ID_RESUME))
ABORT("Out of order mprotect thread request");
}
# endif /* THREADS */
if (r != MACH_MSG_SUCCESS) {
if (GC_print_stats)
GC_log_printf("mach_msg failed with code %d: %s\n", (int)r,
mach_error_string(r));
ABORT("mach_msg failed");
}
switch(id) {
# if defined(THREADS)
case ID_STOP:
if(GC_mprotect_state != GC_MP_NORMAL)
ABORT("Called mprotect_stop when state wasn't normal");
GC_mprotect_state = GC_MP_DISCARDING;
break;
case ID_RESUME:
if(GC_mprotect_state != GC_MP_STOPPED)
ABORT("Called mprotect_resume when state wasn't stopped");
GC_mprotect_state = GC_MP_NORMAL;
GC_mprotect_thread_reply();
break;
# endif /* THREADS */
default:
/* Handle the message (calls catch_exception_raise) */
if(!exc_server(&msg.head, &reply.head))
ABORT("exc_server failed");
/* Send the reply */
r = mach_msg(&reply.head, MACH_SEND_MSG, reply.head.msgh_size, 0,
MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE,
MACH_PORT_NULL);
if(r != MACH_MSG_SUCCESS) {
/* This will fail if the thread dies, but the thread */
/* shouldn't die... */
# ifdef BROKEN_EXCEPTION_HANDLING
GC_err_printf("mach_msg failed with %d %s while sending "
"exc reply\n", (int)r, mach_error_string(r));
# else
ABORT("mach_msg failed while sending exception reply");
# endif
}
} /* switch */
} /* for(;;) */
/* NOT REACHED */
return NULL;
}
/* All this SIGBUS code shouldn't be necessary. All protection faults should
be going through the mach exception handler. However, it seems a SIGBUS is
occasionally sent for some unknown reason. Even more odd, it seems to be
meaningless and safe to ignore. */
#ifdef BROKEN_EXCEPTION_HANDLING
/* Updates to this aren't atomic, but the SIGBUSs seem pretty rare. */
/* Even if this doesn't get updated property, it isn't really a proble. */
STATIC int GC_sigbus_count = 0;
STATIC void GC_darwin_sigbus(int num, siginfo_t *sip, void *context)
{
if (num != SIGBUS)
ABORT("Got a non-sigbus signal in the sigbus handler");
/* Ugh... some seem safe to ignore, but too many in a row probably means
trouble. GC_sigbus_count is reset for each mach exception that is
handled */
if (GC_sigbus_count >= 8) {
ABORT("Got more than 8 SIGBUSs in a row!");
} else {
GC_sigbus_count++;
WARN("Ignoring SIGBUS.\n", 0);
}
}
#endif /* BROKEN_EXCEPTION_HANDLING */
GC_INNER void GC_dirty_init(void)
{
kern_return_t r;
mach_port_t me;
pthread_t thread;
pthread_attr_t attr;
exception_mask_t mask;
if (GC_print_stats == VERBOSE)
GC_log_printf(
"Initializing mach/darwin mprotect virtual dirty bit implementation\n");
# ifdef BROKEN_EXCEPTION_HANDLING
WARN("Enabling workarounds for various darwin "
"exception handling bugs.\n", 0);
# endif
GC_dirty_maintained = TRUE;
if (GC_page_size % HBLKSIZE != 0) {
ABORT("Page size not multiple of HBLKSIZE");
}
GC_task_self = me = mach_task_self();
r = mach_port_allocate(me, MACH_PORT_RIGHT_RECEIVE, &GC_ports.exception);
if (r != KERN_SUCCESS)
ABORT("mach_port_allocate failed (exception port)");
r = mach_port_insert_right(me, GC_ports.exception, GC_ports.exception,
MACH_MSG_TYPE_MAKE_SEND);
if (r != KERN_SUCCESS)
ABORT("mach_port_insert_right failed (exception port)");
# if defined(THREADS)
r = mach_port_allocate(me, MACH_PORT_RIGHT_RECEIVE, &GC_ports.reply);
if(r != KERN_SUCCESS)
ABORT("mach_port_allocate failed (reply port)");
# endif
/* The exceptions we want to catch */
mask = EXC_MASK_BAD_ACCESS;
r = task_get_exception_ports(me, mask, GC_old_exc_ports.masks,
&GC_old_exc_ports.count, GC_old_exc_ports.ports,
GC_old_exc_ports.behaviors,
GC_old_exc_ports.flavors);
if (r != KERN_SUCCESS)
ABORT("task_get_exception_ports failed");
r = task_set_exception_ports(me, mask, GC_ports.exception, EXCEPTION_DEFAULT,
GC_MACH_THREAD_STATE);
if (r != KERN_SUCCESS)
ABORT("task_set_exception_ports failed");
if (pthread_attr_init(&attr) != 0)
ABORT("pthread_attr_init failed");
if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) != 0)
ABORT("pthread_attr_setdetachedstate failed");
# undef pthread_create
/* This will call the real pthread function, not our wrapper */
if (pthread_create(&thread, &attr, GC_mprotect_thread, NULL) != 0)
ABORT("pthread_create failed");
pthread_attr_destroy(&attr);
/* Setup the sigbus handler for ignoring the meaningless SIGBUSs */
# ifdef BROKEN_EXCEPTION_HANDLING
{
struct sigaction sa, oldsa;
sa.sa_handler = (SIG_HNDLR_PTR)GC_darwin_sigbus;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART|SA_SIGINFO;
if (sigaction(SIGBUS, &sa, &oldsa) < 0)
ABORT("sigaction failed");
if ((SIG_HNDLR_PTR)oldsa.sa_handler != SIG_DFL) {
if (GC_print_stats == VERBOSE)
GC_err_printf("Replaced other SIGBUS handler\n");
}
}
# endif /* BROKEN_EXCEPTION_HANDLING */
}
/* The source code for Apple's GDB was used as a reference for the */
/* exception forwarding code. This code is similar to be GDB code only */
/* because there is only one way to do it. */
STATIC kern_return_t GC_forward_exception(mach_port_t thread, mach_port_t task,
exception_type_t exception,
exception_data_t data,
mach_msg_type_number_t data_count)
{
unsigned int i;
kern_return_t r;
mach_port_t port;
exception_behavior_t behavior;
thread_state_flavor_t flavor;
thread_state_data_t thread_state;
mach_msg_type_number_t thread_state_count = THREAD_STATE_MAX;
for (i=0; i < GC_old_exc_ports.count; i++)
if (GC_old_exc_ports.masks[i] & (1 << exception))
break;
if (i == GC_old_exc_ports.count)
ABORT("No handler for exception!");
port = GC_old_exc_ports.ports[i];
behavior = GC_old_exc_ports.behaviors[i];
flavor = GC_old_exc_ports.flavors[i];
if (behavior == EXCEPTION_STATE || behavior == EXCEPTION_STATE_IDENTITY) {
r = thread_get_state(thread, flavor, thread_state, &thread_state_count);
if(r != KERN_SUCCESS)
ABORT("thread_get_state failed in forward_exception");
}
switch(behavior) {
case EXCEPTION_STATE:
r = exception_raise_state(port, thread, task, exception, data, data_count,
&flavor, thread_state, thread_state_count,
thread_state, &thread_state_count);
break;
case EXCEPTION_STATE_IDENTITY:
r = exception_raise_state_identity(port, thread, task, exception, data,
data_count, &flavor, thread_state,
thread_state_count, thread_state,
&thread_state_count);
break;
/* case EXCEPTION_DEFAULT: */ /* default signal handlers */
default: /* user-supplied signal handlers */
r = exception_raise(port, thread, task, exception, data, data_count);
}
if (behavior == EXCEPTION_STATE || behavior == EXCEPTION_STATE_IDENTITY) {
r = thread_set_state(thread, flavor, thread_state, thread_state_count);
if (r != KERN_SUCCESS)
ABORT("thread_set_state failed in forward_exception");
}
return r;
}
#define FWD() GC_forward_exception(thread, task, exception, code, code_count)
#ifdef ARM32
# define DARWIN_EXC_STATE ARM_EXCEPTION_STATE
# define DARWIN_EXC_STATE_COUNT ARM_EXCEPTION_STATE_COUNT
# define DARWIN_EXC_STATE_T arm_exception_state_t
# define DARWIN_EXC_STATE_DAR THREAD_FLD(far)
#elif defined(POWERPC)
# if CPP_WORDSZ == 32
# define DARWIN_EXC_STATE PPC_EXCEPTION_STATE
# define DARWIN_EXC_STATE_COUNT PPC_EXCEPTION_STATE_COUNT
# define DARWIN_EXC_STATE_T ppc_exception_state_t
# else
# define DARWIN_EXC_STATE PPC_EXCEPTION_STATE64
# define DARWIN_EXC_STATE_COUNT PPC_EXCEPTION_STATE64_COUNT
# define DARWIN_EXC_STATE_T ppc_exception_state64_t
# endif
# define DARWIN_EXC_STATE_DAR THREAD_FLD(dar)
#elif defined(I386) || defined(X86_64)
# if CPP_WORDSZ == 32
# define DARWIN_EXC_STATE x86_EXCEPTION_STATE32
# define DARWIN_EXC_STATE_COUNT x86_EXCEPTION_STATE32_COUNT
# define DARWIN_EXC_STATE_T x86_exception_state32_t
# else
# define DARWIN_EXC_STATE x86_EXCEPTION_STATE64
# define DARWIN_EXC_STATE_COUNT x86_EXCEPTION_STATE64_COUNT
# define DARWIN_EXC_STATE_T x86_exception_state64_t
# endif
# define DARWIN_EXC_STATE_DAR THREAD_FLD(faultvaddr)
#else
# error FIXME for non-arm/ppc/x86 darwin
#endif
/* This violates the namespace rules but there isn't anything that can */
/* be done about it. The exception handling stuff is hard coded to */
/* call this. catch_exception_raise, catch_exception_raise_state and */
/* and catch_exception_raise_state_identity are called from OS. */
GC_API_OSCALL kern_return_t
catch_exception_raise(mach_port_t exception_port, mach_port_t thread,
mach_port_t task, exception_type_t exception,
exception_data_t code, mach_msg_type_number_t code_count)
{
kern_return_t r;
char *addr;
struct hblk *h;
unsigned int i;
thread_state_flavor_t flavor = DARWIN_EXC_STATE;
mach_msg_type_number_t exc_state_count = DARWIN_EXC_STATE_COUNT;
DARWIN_EXC_STATE_T exc_state;
if (exception != EXC_BAD_ACCESS || code[0] != KERN_PROTECTION_FAILURE) {
# ifdef DEBUG_EXCEPTION_HANDLING
/* We aren't interested, pass it on to the old handler */
GC_log_printf("Exception: 0x%x Code: 0x%x 0x%x in catch...\n",
exception, code_count > 0 ? code[0] : -1,
code_count > 1 ? code[1] : -1);
# endif
return FWD();
}
r = thread_get_state(thread, flavor, (natural_t*)&exc_state,
&exc_state_count);
if(r != KERN_SUCCESS) {
/* The thread is supposed to be suspended while the exception */
/* handler is called. This shouldn't fail. */
# ifdef BROKEN_EXCEPTION_HANDLING
GC_err_printf("thread_get_state failed in catch_exception_raise\n");
return KERN_SUCCESS;
# else
ABORT("thread_get_state failed in catch_exception_raise");
# endif
}
/* This is the address that caused the fault */
addr = (char*) exc_state.DARWIN_EXC_STATE_DAR;
if (HDR(addr) == 0) {
/* Ugh... just like the SIGBUS problem above, it seems we get */
/* a bogus KERN_PROTECTION_FAILURE every once and a while. We wait */
/* till we get a bunch in a row before doing anything about it. */
/* If a "real" fault ever occurs it'll just keep faulting over and */
/* over and we'll hit the limit pretty quickly. */
# ifdef BROKEN_EXCEPTION_HANDLING
static char *last_fault;
static int last_fault_count;
if(addr != last_fault) {
last_fault = addr;
last_fault_count = 0;
}
if(++last_fault_count < 32) {
if(last_fault_count == 1)
WARN("Ignoring KERN_PROTECTION_FAILURE at %p\n", addr);
return KERN_SUCCESS;
}
GC_err_printf(
"Unexpected KERN_PROTECTION_FAILURE at %p; aborting...\n", addr);
/* Can't pass it along to the signal handler because that is */
/* ignoring SIGBUS signals. We also shouldn't call ABORT here as */
/* signals don't always work too well from the exception handler. */
exit(EXIT_FAILURE);
# else /* BROKEN_EXCEPTION_HANDLING */
/* Pass it along to the next exception handler
(which should call SIGBUS/SIGSEGV) */
return FWD();
# endif /* !BROKEN_EXCEPTION_HANDLING */
}
# ifdef BROKEN_EXCEPTION_HANDLING
/* Reset the number of consecutive SIGBUSs */
GC_sigbus_count = 0;
# endif
if (GC_mprotect_state == GC_MP_NORMAL) { /* common case */
h = (struct hblk*)((word)addr & ~(GC_page_size-1));
UNPROTECT(h, GC_page_size);
for (i = 0; i < divHBLKSZ(GC_page_size); i++) {
register int index = PHT_HASH(h+i);
async_set_pht_entry_from_index(GC_dirty_pages, index);
}
} else if (GC_mprotect_state == GC_MP_DISCARDING) {
/* Lie to the thread for now. No sense UNPROTECT()ing the memory
when we're just going to PROTECT() it again later. The thread
will just fault again once it resumes */
} else {
/* Shouldn't happen, i don't think */
GC_err_printf("KERN_PROTECTION_FAILURE while world is stopped\n");
return FWD();
}
return KERN_SUCCESS;
}
#undef FWD
#ifndef NO_DESC_CATCH_EXCEPTION_RAISE
/* These symbols should have REFERENCED_DYNAMICALLY (0x10) bit set to */
/* let strip know they are not to be stripped. */
__asm__(".desc _catch_exception_raise, 0x10");
__asm__(".desc _catch_exception_raise_state, 0x10");
__asm__(".desc _catch_exception_raise_state_identity, 0x10");
#endif
#endif /* DARWIN && MPROTECT_VDB */
#ifndef HAVE_INCREMENTAL_PROTECTION_NEEDS
GC_API int GC_CALL GC_incremental_protection_needs(void)
{
return GC_PROTECTS_NONE;
}
#endif /* !HAVE_INCREMENTAL_PROTECTION_NEEDS */
#ifdef ECOS
/* Undo sbrk() redirection. */
# undef sbrk
#endif
/* If value is non-zero then allocate executable memory. */
GC_API void GC_CALL GC_set_pages_executable(int value)
{
GC_ASSERT(!GC_is_initialized);
/* Even if IGNORE_PAGES_EXECUTABLE is defined, GC_pages_executable is */
/* touched here to prevent a compiler warning. */
GC_pages_executable = (GC_bool)(value != 0);
}
/* Returns non-zero if the GC-allocated memory is executable. */
/* GC_get_pages_executable is defined after all the places */
/* where GC_get_pages_executable is undefined. */
GC_API int GC_CALL GC_get_pages_executable(void)
{
# ifdef IGNORE_PAGES_EXECUTABLE
return 1; /* Always allocate executable memory. */
# else
return (int)GC_pages_executable;
# endif
}
/* Call stack save code for debugging. Should probably be in */
/* mach_dep.c, but that requires reorganization. */
/* I suspect the following works for most X86 *nix variants, so */
/* long as the frame pointer is explicitly stored. In the case of gcc, */
/* compiler flags (e.g. -fomit-frame-pointer) determine whether it is. */
#if defined(I386) && defined(LINUX) && defined(SAVE_CALL_CHAIN)
# include <features.h>
struct frame {
struct frame *fr_savfp;
long fr_savpc;
long fr_arg[NARGS]; /* All the arguments go here. */
};
#endif
#if defined(SPARC)
# if defined(LINUX)
# include <features.h>
struct frame {
long fr_local[8];
long fr_arg[6];
struct frame *fr_savfp;
long fr_savpc;
# ifndef __arch64__
char *fr_stret;
# endif
long fr_argd[6];
long fr_argx[0];
};
# elif defined (DRSNX)
# include <sys/sparc/frame.h>
# elif defined(OPENBSD)
# include <frame.h>
# elif defined(FREEBSD) || defined(NETBSD)
# include <machine/frame.h>
# else
# include <sys/frame.h>
# endif
# if NARGS > 6
# error We only know how to get the first 6 arguments
# endif
#endif /* SPARC */
#ifdef NEED_CALLINFO
/* Fill in the pc and argument information for up to NFRAMES of my */
/* callers. Ignore my frame and my callers frame. */
#ifdef LINUX
# include <unistd.h>
#endif
#endif /* NEED_CALLINFO */
#if defined(GC_HAVE_BUILTIN_BACKTRACE)
# ifdef _MSC_VER
# include "private/msvc_dbg.h"
# else
# include <execinfo.h>
# endif
#endif
#ifdef SAVE_CALL_CHAIN
#if NARGS == 0 && NFRAMES % 2 == 0 /* No padding */ \
&& defined(GC_HAVE_BUILTIN_BACKTRACE)
#ifdef REDIRECT_MALLOC
/* Deal with possible malloc calls in backtrace by omitting */
/* the infinitely recursing backtrace. */
# ifdef THREADS
__thread /* If your compiler doesn't understand this */
/* you could use something like pthread_getspecific. */
# endif
GC_in_save_callers = FALSE;
#endif
GC_INNER void GC_save_callers(struct callinfo info[NFRAMES])
{
void * tmp_info[NFRAMES + 1];
int npcs, i;
# define IGNORE_FRAMES 1
/* We retrieve NFRAMES+1 pc values, but discard the first, since it */
/* points to our own frame. */
# ifdef REDIRECT_MALLOC
if (GC_in_save_callers) {
info[0].ci_pc = (word)(&GC_save_callers);
for (i = 1; i < NFRAMES; ++i) info[i].ci_pc = 0;
return;
}
GC_in_save_callers = TRUE;
# endif
GC_STATIC_ASSERT(sizeof(struct callinfo) == sizeof(void *));
npcs = backtrace((void **)tmp_info, NFRAMES + IGNORE_FRAMES);
BCOPY(tmp_info+IGNORE_FRAMES, info, (npcs - IGNORE_FRAMES) * sizeof(void *));
for (i = npcs - IGNORE_FRAMES; i < NFRAMES; ++i) info[i].ci_pc = 0;
# ifdef REDIRECT_MALLOC
GC_in_save_callers = FALSE;
# endif
}
#else /* No builtin backtrace; do it ourselves */
#if (defined(OPENBSD) || defined(NETBSD) || defined(FREEBSD)) && defined(SPARC)
# define FR_SAVFP fr_fp
# define FR_SAVPC fr_pc
#else
# define FR_SAVFP fr_savfp
# define FR_SAVPC fr_savpc
#endif
#if defined(SPARC) && (defined(__arch64__) || defined(__sparcv9))
# define BIAS 2047
#else
# define BIAS 0
#endif
GC_INNER void GC_save_callers(struct callinfo info[NFRAMES])
{
struct frame *frame;
struct frame *fp;
int nframes = 0;
# ifdef I386
/* We assume this is turned on only with gcc as the compiler. */
asm("movl %%ebp,%0" : "=r"(frame));
fp = frame;
# else
frame = (struct frame *)GC_save_regs_in_stack();
fp = (struct frame *)((long) frame -> FR_SAVFP + BIAS);
#endif
for (; (!(fp HOTTER_THAN frame) && !(GC_stackbottom HOTTER_THAN (ptr_t)fp)
&& (nframes < NFRAMES));
fp = (struct frame *)((long) fp -> FR_SAVFP + BIAS), nframes++) {
register int i;
info[nframes].ci_pc = fp->FR_SAVPC;
# if NARGS > 0
for (i = 0; i < NARGS; i++) {
info[nframes].ci_arg[i] = ~(fp->fr_arg[i]);
}
# endif /* NARGS > 0 */
}
if (nframes < NFRAMES) info[nframes].ci_pc = 0;
}
#endif /* No builtin backtrace */
#endif /* SAVE_CALL_CHAIN */
#ifdef NEED_CALLINFO
/* Print info to stderr. We do NOT hold the allocation lock */
GC_INNER void GC_print_callers(struct callinfo info[NFRAMES])
{
int i;
static int reentry_count = 0;
GC_bool stop = FALSE;
DCL_LOCK_STATE;
/* FIXME: This should probably use a different lock, so that we */
/* become callable with or without the allocation lock. */
LOCK();
++reentry_count;
UNLOCK();
# if NFRAMES == 1
GC_err_printf("\tCaller at allocation:\n");
# else
GC_err_printf("\tCall chain at allocation:\n");
# endif
for (i = 0; i < NFRAMES && !stop; i++) {
if (info[i].ci_pc == 0) break;
# if NARGS > 0
{
int j;
GC_err_printf("\t\targs: ");
for (j = 0; j < NARGS; j++) {
if (j != 0) GC_err_printf(", ");
GC_err_printf("%d (0x%X)", ~(info[i].ci_arg[j]),
~(info[i].ci_arg[j]));
}
GC_err_printf("\n");
}
# endif
if (reentry_count > 1) {
/* We were called during an allocation during */
/* a previous GC_print_callers call; punt. */
GC_err_printf("\t\t##PC##= 0x%lx\n", info[i].ci_pc);
continue;
}
{
# ifdef LINUX
FILE *pipe;
# endif
# if defined(GC_HAVE_BUILTIN_BACKTRACE) \
&& !defined(GC_BACKTRACE_SYMBOLS_BROKEN)
char **sym_name =
backtrace_symbols((void **)(&(info[i].ci_pc)), 1);
char *name = sym_name[0];
# else
char buf[40];
char *name = buf;
sprintf(buf, "##PC##= 0x%lx", info[i].ci_pc);
# endif
# if defined(LINUX) && !defined(SMALL_CONFIG)
/* Try for a line number. */
{
# define EXE_SZ 100
static char exe_name[EXE_SZ];
# define CMD_SZ 200
char cmd_buf[CMD_SZ];
# define RESULT_SZ 200
static char result_buf[RESULT_SZ];
size_t result_len;
char *old_preload;
# define PRELOAD_SZ 200
char preload_buf[PRELOAD_SZ];
static GC_bool found_exe_name = FALSE;
static GC_bool will_fail = FALSE;
int ret_code;
/* Try to get it via a hairy and expensive scheme. */
/* First we get the name of the executable: */
if (will_fail) goto out;
if (!found_exe_name) {
ret_code = readlink("/proc/self/exe", exe_name, EXE_SZ);
if (ret_code < 0 || ret_code >= EXE_SZ
|| exe_name[0] != '/') {
will_fail = TRUE; /* Don't try again. */
goto out;
}
exe_name[ret_code] = '\0';
found_exe_name = TRUE;
}
/* Then we use popen to start addr2line -e <exe> <addr> */
/* There are faster ways to do this, but hopefully this */
/* isn't time critical. */
sprintf(cmd_buf, "/usr/bin/addr2line -f -e %s 0x%lx", exe_name,
(unsigned long)info[i].ci_pc);
old_preload = GETENV("LD_PRELOAD");
if (0 != old_preload) {
if (strlen (old_preload) >= PRELOAD_SZ) {
will_fail = TRUE;
goto out;
}
strcpy (preload_buf, old_preload);
unsetenv ("LD_PRELOAD");
}
pipe = popen(cmd_buf, "r");
if (0 != old_preload
&& 0 != setenv ("LD_PRELOAD", preload_buf, 0)) {
WARN("Failed to reset LD_PRELOAD\n", 0);
}
if (pipe == NULL
|| (result_len = fread(result_buf, 1, RESULT_SZ - 1, pipe))
== 0) {
if (pipe != NULL) pclose(pipe);
will_fail = TRUE;
goto out;
}
if (result_buf[result_len - 1] == '\n') --result_len;
result_buf[result_len] = 0;
if (result_buf[0] == '?'
|| (result_buf[result_len-2] == ':'
&& result_buf[result_len-1] == '0')) {
pclose(pipe);
goto out;
}
/* Get rid of embedded newline, if any. Test for "main" */
{
char * nl = strchr(result_buf, '\n');
if (nl != NULL && nl < result_buf + result_len) {
*nl = ':';
}
if (strncmp(result_buf, "main", nl - result_buf) == 0) {
stop = TRUE;
}
}
if (result_len < RESULT_SZ - 25) {
/* Add in hex address */
sprintf(result_buf + result_len, " [0x%lx]",
(unsigned long)info[i].ci_pc);
}
name = result_buf;
pclose(pipe);
out:;
}
# endif /* LINUX */
GC_err_printf("\t\t%s\n", name);
# if defined(GC_HAVE_BUILTIN_BACKTRACE) \
&& !defined(GC_BACKTRACE_SYMBOLS_BROKEN)
free(sym_name); /* May call GC_free; that's OK */
# endif
}
}
LOCK();
--reentry_count;
UNLOCK();
}
#endif /* NEED_CALLINFO */
#if defined(LINUX) && defined(__ELF__) && !defined(SMALL_CONFIG)
/* Dump /proc/self/maps to GC_stderr, to enable looking up names for */
/* addresses in FIND_LEAK output. */
void GC_print_address_map(void)
{
GC_err_printf("---------- Begin address map ----------\n");
GC_err_puts(GC_get_maps());
GC_err_printf("---------- End address map ----------\n");
}
#endif /* LINUX && ELF */