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/*
* interrupt-handling magic
*/
/*
* This software is part of the SBCL system. See the README file for
* more information.
*
* This software is derived from the CMU CL system, which was
* written at Carnegie Mellon University and released into the
* public domain. The software is in the public domain and is
* provided with absolutely no warranty. See the COPYING and CREDITS
* files for more information.
*/
/* As far as I can tell, what's going on here is:
*
* In the case of most signals, when Lisp asks us to handle the
* signal, the outermost handler (the one actually passed to UNIX) is
* either interrupt_handle_now(..) or maybe_now_maybe_later(..).
* In that case, the Lisp-level handler is stored in interrupt_handlers[..]
* and interrupt_low_level_handlers[..] is cleared.
*
* However, some signals need special handling, e.g.
*
* o the SIGSEGV (for e.g. Linux) or SIGBUS (for e.g. FreeBSD) used by the
* garbage collector to detect violations of write protection,
* because some cases of such signals (e.g. GC-related violations of
* write protection) are handled at C level and never passed on to
* Lisp. For such signals, we still store any Lisp-level handler
* in interrupt_handlers[..], but for the outermost handle we use
* the value from interrupt_low_level_handlers[..], instead of the
* ordinary interrupt_handle_now(..) or interrupt_handle_later(..).
*
* o the SIGTRAP (Linux/Alpha) which Lisp code uses to handle breakpoints,
* pseudo-atomic sections, and some classes of error (e.g. "function
* not defined"). This never goes anywhere near the Lisp handlers at all.
* See runtime/alpha-arch.c and code/signal.lisp
*
* - WHN 20000728, dan 20010128 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "sbcl.h"
#include "runtime.h"
#include "arch.h"
#include "os.h"
#include "interrupt.h"
#include "globals.h"
#include "lispregs.h"
#include "validate.h"
#include "monitor.h"
#include "gc.h"
#include "alloc.h"
#include "dynbind.h"
#include "interr.h"
#include "genesis/fdefn.h"
#include "genesis/simple-fun.h"
void run_deferred_handler(struct interrupt_data *data, void *v_context) ;
static void store_signal_data_for_later (struct interrupt_data *data,
void *handler, int signal,
siginfo_t *info,
os_context_t *context);
boolean interrupt_maybe_gc_int(int signal, siginfo_t *info, void *v_context);
extern volatile lispobj all_threads_lock;
/*
* This is a workaround for some slightly silly Linux/GNU Libc
* behaviour: glibc defines sigset_t to support 1024 signals, which is
* more than the kernel. This is usually not a problem, but becomes
* one when we want to save a signal mask from a ucontext, and restore
* it later into another ucontext: the ucontext is allocated on the
* stack by the kernel, so copying a libc-sized sigset_t into it will
* overflow and cause other data on the stack to be corrupted */
#define REAL_SIGSET_SIZE_BYTES ((NSIG/8))
void sigaddset_blockable(sigset_t *s)
{
sigaddset(s, SIGHUP);
sigaddset(s, SIGINT);
sigaddset(s, SIGQUIT);
sigaddset(s, SIGPIPE);
sigaddset(s, SIGALRM);
sigaddset(s, SIGURG);
sigaddset(s, SIGFPE);
sigaddset(s, SIGTSTP);
sigaddset(s, SIGCHLD);
sigaddset(s, SIGIO);
sigaddset(s, SIGXCPU);
sigaddset(s, SIGXFSZ);
sigaddset(s, SIGVTALRM);
sigaddset(s, SIGPROF);
sigaddset(s, SIGWINCH);
sigaddset(s, SIGUSR1);
sigaddset(s, SIGUSR2);
#ifdef LISP_FEATURE_SB_THREAD
sigaddset(s, SIG_STOP_FOR_GC);
sigaddset(s, SIG_INTERRUPT_THREAD);
#endif
}
/* When we catch an internal error, should we pass it back to Lisp to
* be handled in a high-level way? (Early in cold init, the answer is
* 'no', because Lisp is still too brain-dead to handle anything.
* After sufficient initialization has been completed, the answer
* becomes 'yes'.) */
boolean internal_errors_enabled = 0;
struct interrupt_data * global_interrupt_data;
/* At the toplevel repl we routinely call this function. The signal
* mask ought to be clear anyway most of the time, but may be non-zero
* if we were interrupted e.g. while waiting for a queue. */
void reset_signal_mask ()
{
sigset_t new;
sigemptyset(&new);
sigprocmask(SIG_SETMASK,&new,0);
}
/*
* utility routines used by various signal handlers
*/
void
build_fake_control_stack_frames(struct thread *th,os_context_t *context)
{
#ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
lispobj oldcont;
/* Build a fake stack frame or frames */
current_control_frame_pointer =
(lispobj *)(*os_context_register_addr(context, reg_CSP));
if ((lispobj *)(*os_context_register_addr(context, reg_CFP))
== current_control_frame_pointer) {
/* There is a small window during call where the callee's
* frame isn't built yet. */
if (lowtag_of(*os_context_register_addr(context, reg_CODE))
== FUN_POINTER_LOWTAG) {
/* We have called, but not built the new frame, so
* build it for them. */
current_control_frame_pointer[0] =
*os_context_register_addr(context, reg_OCFP);
current_control_frame_pointer[1] =
*os_context_register_addr(context, reg_LRA);
current_control_frame_pointer += 8;
/* Build our frame on top of it. */
oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
}
else {
/* We haven't yet called, build our frame as if the
* partial frame wasn't there. */
oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
}
}
/* We can't tell whether we are still in the caller if it had to
* allocate a stack frame due to stack arguments. */
/* This observation provoked some past CMUCL maintainer to ask
* "Can anything strange happen during return?" */
else {
/* normal case */
oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
}
current_control_stack_pointer = current_control_frame_pointer + 8;
current_control_frame_pointer[0] = oldcont;
current_control_frame_pointer[1] = NIL;
current_control_frame_pointer[2] =
(lispobj)(*os_context_register_addr(context, reg_CODE));
#endif
}
void
fake_foreign_function_call(os_context_t *context)
{
int context_index;
struct thread *thread=arch_os_get_current_thread();
/* Get current Lisp state from context. */
#ifdef reg_ALLOC
dynamic_space_free_pointer =
(lispobj *)(*os_context_register_addr(context, reg_ALLOC));
#ifdef alpha
if ((long)dynamic_space_free_pointer & 1) {
lose("dead in fake_foreign_function_call, context = %x", context);
}
#endif
#endif
#ifdef reg_BSP
current_binding_stack_pointer =
(lispobj *)(*os_context_register_addr(context, reg_BSP));
#endif
build_fake_control_stack_frames(thread,context);
/* Do dynamic binding of the active interrupt context index
* and save the context in the context array. */
context_index =
fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
if (context_index >= MAX_INTERRUPTS) {
lose("maximum interrupt nesting depth (%d) exceeded", MAX_INTERRUPTS);
}
bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
make_fixnum(context_index + 1),thread);
thread->interrupt_contexts[context_index] = context;
/* no longer in Lisp now */
foreign_function_call_active = 1;
}
/* blocks all blockable signals. If you are calling from a signal handler,
* the usual signal mask will be restored from the context when the handler
* finishes. Otherwise, be careful */
void
undo_fake_foreign_function_call(os_context_t *context)
{
struct thread *thread=arch_os_get_current_thread();
/* Block all blockable signals. */
sigset_t block;
sigemptyset(&block);
sigaddset_blockable(&block);
sigprocmask(SIG_BLOCK, &block, 0);
/* going back into Lisp */
foreign_function_call_active = 0;
/* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
unbind(thread);
#ifdef reg_ALLOC
/* Put the dynamic space free pointer back into the context. */
*os_context_register_addr(context, reg_ALLOC) =
(unsigned long) dynamic_space_free_pointer;
#endif
}
/* a handler for the signal caused by execution of a trap opcode
* signalling an internal error */
void
interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
boolean continuable)
{
lispobj context_sap = 0;
fake_foreign_function_call(context);
/* Allocate the SAP object while the interrupts are still
* disabled. */
if (internal_errors_enabled) {
context_sap = alloc_sap(context);
}
sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
if (internal_errors_enabled) {
SHOW("in interrupt_internal_error");
#ifdef QSHOW
/* Display some rudimentary debugging information about the
* error, so that even if the Lisp error handler gets badly
* confused, we have a chance to determine what's going on. */
describe_internal_error(context);
#endif
funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
continuable ? T : NIL);
} else {
describe_internal_error(context);
/* There's no good way to recover from an internal error
* before the Lisp error handling mechanism is set up. */
lose("internal error too early in init, can't recover");
}
undo_fake_foreign_function_call(context); /* blocks signals again */
if (continuable) {
arch_skip_instruction(context);
}
}
void
interrupt_handle_pending(os_context_t *context)
{
struct thread *thread;
struct interrupt_data *data;
thread=arch_os_get_current_thread();
data=thread->interrupt_data;
/* FIXME I'm not altogether sure this is appropriate if we're
* here as the result of a pseudo-atomic */
SetSymbolValue(INTERRUPT_PENDING, NIL,thread);
/* restore the saved signal mask from the original signal (the
* one that interrupted us during the critical section) into the
* os_context for the signal we're currently in the handler for.
* This should ensure that when we return from the handler the
* blocked signals are unblocked */
memcpy(os_context_sigmask_addr(context), &data->pending_mask,
REAL_SIGSET_SIZE_BYTES);
sigemptyset(&data->pending_mask);
/* This will break on sparc linux: the deferred handler really wants
* to be called with a void_context */
run_deferred_handler(data,(void *)context);
}
/*
* the two main signal handlers:
* interrupt_handle_now(..)
* maybe_now_maybe_later(..)
*
* to which we have added interrupt_handle_now_handler(..). Why?
* Well, mostly because the SPARC/Linux platform doesn't quite do
* signals the way we want them done. The third argument in the
* handler isn't filled in by the kernel properly, so we fix it up
* ourselves in the arch_os_get_context(..) function; however, we only
* want to do this when we first hit the handler, and not when
* interrupt_handle_now(..) is being called from some other handler
* (when the fixup will already have been done). -- CSR, 2002-07-23
*/
void
interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
{
os_context_t *context = (os_context_t*)void_context;
struct thread *thread=arch_os_get_current_thread();
#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
boolean were_in_lisp;
#endif
union interrupt_handler handler;
#ifdef LISP_FEATURE_LINUX
/* Under Linux on some architectures, we appear to have to restore
the FPU control word from the context, as after the signal is
delivered we appear to have a null FPU control word. */
os_restore_fp_control(context);
#endif
handler = thread->interrupt_data->interrupt_handlers[signal];
if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
return;
}
#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
were_in_lisp = !foreign_function_call_active;
if (were_in_lisp)
#endif
{
fake_foreign_function_call(context);
}
#ifdef QSHOW_SIGNALS
FSHOW((stderr,
"/entering interrupt_handle_now(%d, info, context)\n",
signal));
#endif
if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
/* This can happen if someone tries to ignore or default one
* of the signals we need for runtime support, and the runtime
* support decides to pass on it. */
lose("no handler for signal %d in interrupt_handle_now(..)", signal);
} else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
/* Once we've decided what to do about contexts in a
* return-elsewhere world (the original context will no longer
* be available; should we copy it or was nobody using it anyway?)
* then we should convert this to return-elsewhere */
/* CMUCL comment said "Allocate the SAPs while the interrupts
* are still disabled.". I (dan, 2003.08.21) assume this is
* because we're not in pseudoatomic and allocation shouldn't
* be interrupted. In which case it's no longer an issue as
* all our allocation from C now goes through a PA wrapper,
* but still, doesn't hurt */
lispobj info_sap,context_sap = alloc_sap(context);
info_sap = alloc_sap(info);
/* Allow signals again. */
sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
#ifdef QSHOW_SIGNALS
SHOW("calling Lisp-level handler");
#endif
funcall3(handler.lisp,
make_fixnum(signal),
info_sap,
context_sap);
} else {
#ifdef QSHOW_SIGNALS
SHOW("calling C-level handler");
#endif
/* Allow signals again. */
sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
(*handler.c)(signal, info, void_context);
}
#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
if (were_in_lisp)
#endif
{
undo_fake_foreign_function_call(context); /* block signals again */
}
#ifdef QSHOW_SIGNALS
FSHOW((stderr,
"/returning from interrupt_handle_now(%d, info, context)\n",
signal));
#endif
}
/* This is called at the end of a critical section if the indications
* are that some signal was deferred during the section. Note that as
* far as C or the kernel is concerned we dealt with the signal
* already; we're just doing the Lisp-level processing now that we
* put off then */
void
run_deferred_handler(struct interrupt_data *data, void *v_context) {
(*(data->pending_handler))
(data->pending_signal,&(data->pending_info), v_context);
data->pending_handler=0;
}
boolean
maybe_defer_handler(void *handler, struct interrupt_data *data,
int signal, siginfo_t *info, os_context_t *context)
{
struct thread *thread=arch_os_get_current_thread();
if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
store_signal_data_for_later(data,handler,signal,info,context);
SetSymbolValue(INTERRUPT_PENDING, T,thread);
return 1;
}
/* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
* actually use its argument for anything on x86, so this branch
* may succeed even when context is null (gencgc alloc()) */
if (
#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
(!foreign_function_call_active) &&
#endif
arch_pseudo_atomic_atomic(context)) {
store_signal_data_for_later(data,handler,signal,info,context);
arch_set_pseudo_atomic_interrupted(context);
return 1;
}
return 0;
}
static void
store_signal_data_for_later (struct interrupt_data *data, void *handler,
int signal,
siginfo_t *info, os_context_t *context)
{
data->pending_handler = handler;
data->pending_signal = signal;
if(info)
memcpy(&(data->pending_info), info, sizeof(siginfo_t));
if(context) {
/* the signal mask in the context (from before we were
* interrupted) is copied to be restored when
* run_deferred_handler happens. Then the usually-blocked
* signals are added to the mask in the context so that we are
* running with blocked signals when the handler returns */
sigemptyset(&(data->pending_mask));
memcpy(&(data->pending_mask),
os_context_sigmask_addr(context),
REAL_SIGSET_SIZE_BYTES);
sigaddset_blockable(os_context_sigmask_addr(context));
} else {
/* this is also called from gencgc alloc(), in which case
* there has been no signal and is therefore no context. */
sigset_t new;
sigemptyset(&new);
sigaddset_blockable(&new);
sigprocmask(SIG_BLOCK,&new,&(data->pending_mask));
}
}
static void
maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
{
os_context_t *context = arch_os_get_context(&void_context);
struct thread *thread=arch_os_get_current_thread();
struct interrupt_data *data=thread->interrupt_data;
#ifdef LISP_FEATURE_LINUX
os_restore_fp_control(context);
#endif
if(maybe_defer_handler(interrupt_handle_now,data,
signal,info,context))
return;
interrupt_handle_now(signal, info, context);
#ifdef LISP_FEATURE_DARWIN
/* Work around G5 bug */
DARWIN_FIX_CONTEXT(context);
#endif
}
#ifdef LISP_FEATURE_SB_THREAD
void
sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
{
os_context_t *context = arch_os_get_context(&void_context);
struct thread *thread=arch_os_get_current_thread();
struct interrupt_data *data=thread->interrupt_data;
sigset_t ss;
int i;
if(maybe_defer_handler(sig_stop_for_gc_handler,data,
signal,info,context)) {
return;
}
/* need the context stored so it can have registers scavenged */
fake_foreign_function_call(context);
sigemptyset(&ss);
for(i=1;i<NSIG;i++) sigaddset(&ss,i); /* Block everything. */
sigprocmask(SIG_BLOCK,&ss,0);
/* The GC can't tell if a thread is a zombie, so this would be a
* good time to let the kernel reap any of our children in that
* awful state, to stop them from being waited for indefinitely.
* Userland reaping is done later when GC is finished */
mark_dead_threads();
thread->state=STATE_STOPPED;
sigemptyset(&ss); sigaddset(&ss,SIG_STOP_FOR_GC);
sigwaitinfo(&ss,0);
undo_fake_foreign_function_call(context);
}
#endif
void
interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
{
os_context_t *context = arch_os_get_context(&void_context);
interrupt_handle_now(signal, info, context);
#ifdef LISP_FEATURE_DARWIN
DARWIN_FIX_CONTEXT(context);
#endif
}
/*
* stuff to detect and handle hitting the GC trigger
*/
#ifndef LISP_FEATURE_GENCGC
/* since GENCGC has its own way to record trigger */
static boolean
gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
{
if (current_auto_gc_trigger == NULL)
return 0;
else{
void *badaddr=arch_get_bad_addr(signal,info,context);
return (badaddr >= (void *)current_auto_gc_trigger &&
badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE));
}
}
#endif
/* manipulate the signal context and stack such that when the handler
* returns, it will call function instead of whatever it was doing
* previously
*/
extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
extern void post_signal_tramp(void);
void arrange_return_to_lisp_function(os_context_t *context, lispobj function)
{
#if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
void * fun=native_pointer(function);
void *code = &(((struct simple_fun *) fun)->code);
#endif
/* Build a stack frame showing `interrupted' so that the
* user's backtrace makes (as much) sense (as usual) */
#ifdef LISP_FEATURE_X86
/* Suppose the existence of some function that saved all
* registers, called call_into_lisp, then restored GP registers and
* returned. It would look something like this:
push ebp
mov ebp esp
pushad
push $0
push $0
pushl {address of function to call}
call 0x8058db0 <call_into_lisp>
addl $12,%esp
popa
leave
ret
* What we do here is set up the stack that call_into_lisp would
* expect to see if it had been called by this code, and frob the
* signal context so that signal return goes directly to call_into_lisp,
* and when that function (and the lisp function it invoked) returns,
* it returns to the second half of this imaginary function which
* restores all registers and returns to C
* For this to work, the latter part of the imaginary function
* must obviously exist in reality. That would be post_signal_tramp
*/
u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
*(sp-14) = post_signal_tramp; /* return address for call_into_lisp */
*(sp-13) = function; /* args for call_into_lisp : function*/
*(sp-12) = 0; /* arg array */
*(sp-11) = 0; /* no. args */
/* this order matches that used in POPAD */
*(sp-10)=*os_context_register_addr(context,reg_EDI);
*(sp-9)=*os_context_register_addr(context,reg_ESI);
*(sp-8)=*os_context_register_addr(context,reg_ESP)-8;
*(sp-7)=0;
*(sp-6)=*os_context_register_addr(context,reg_EBX);
*(sp-5)=*os_context_register_addr(context,reg_EDX);
*(sp-4)=*os_context_register_addr(context,reg_ECX);
*(sp-3)=*os_context_register_addr(context,reg_EAX);
*(sp-2)=*os_context_register_addr(context,reg_EBP);
*(sp-1)=*os_context_pc_addr(context);
#elif defined(LISP_FEATURE_X86_64)
u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
*(sp-19) = post_signal_tramp; /* return address for call_into_lisp */
*(sp-18)=*os_context_register_addr(context,reg_R15);
*(sp-17)=*os_context_register_addr(context,reg_R14);
*(sp-16)=*os_context_register_addr(context,reg_R13);
*(sp-15)=*os_context_register_addr(context,reg_R12);
*(sp-14)=*os_context_register_addr(context,reg_R11);
*(sp-13)=*os_context_register_addr(context,reg_R10);
*(sp-12)=*os_context_register_addr(context,reg_R9);
*(sp-11)=*os_context_register_addr(context,reg_R8);
*(sp-10)=*os_context_register_addr(context,reg_RDI);
*(sp-9)=*os_context_register_addr(context,reg_RSI);
*(sp-8)=*os_context_register_addr(context,reg_RSP)-16;
*(sp-7)=0;
*(sp-6)=*os_context_register_addr(context,reg_RBX);
*(sp-5)=*os_context_register_addr(context,reg_RDX);
*(sp-4)=*os_context_register_addr(context,reg_RCX);
*(sp-3)=*os_context_register_addr(context,reg_RAX);
*(sp-2)=*os_context_register_addr(context,reg_RBP);
*(sp-1)=*os_context_pc_addr(context);
*os_context_register_addr(context,reg_RDI) = function; /* function */
*os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
*os_context_register_addr(context,reg_RDX) = 0; /* no. args */
#else
struct thread *th=arch_os_get_current_thread();
build_fake_control_stack_frames(th,context);
#endif
#ifdef LISP_FEATURE_X86
*os_context_pc_addr(context) = call_into_lisp;
*os_context_register_addr(context,reg_ECX) = 0;
*os_context_register_addr(context,reg_EBP) = sp-2;
#ifdef __NetBSD__
*os_context_register_addr(context,reg_UESP) = sp-14;
#else
*os_context_register_addr(context,reg_ESP) = sp-14;
#endif
#elif defined(LISP_FEATURE_X86_64)
*os_context_pc_addr(context) = call_into_lisp;
*os_context_register_addr(context,reg_RCX) = 0;
*os_context_register_addr(context,reg_RBP) = sp-2;
*os_context_register_addr(context,reg_RSP) = sp-19;
#else
/* this much of the calling convention is common to all
non-x86 ports */
*os_context_pc_addr(context) = code;
*os_context_register_addr(context,reg_NARGS) = 0;
*os_context_register_addr(context,reg_LIP) = code;
*os_context_register_addr(context,reg_CFP) =
current_control_frame_pointer;
#endif
#ifdef ARCH_HAS_NPC_REGISTER
*os_context_npc_addr(context) =
4 + *os_context_pc_addr(context);
#endif
#ifdef LISP_FEATURE_SPARC
*os_context_register_addr(context,reg_CODE) =
fun + FUN_POINTER_LOWTAG;
#endif
}
#ifdef LISP_FEATURE_SB_THREAD
void interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
{
os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
struct thread *th=arch_os_get_current_thread();
struct interrupt_data *data=
th ? th->interrupt_data : global_interrupt_data;
if(maybe_defer_handler(interrupt_thread_handler,data,num,info,context)){
return ;
}
arrange_return_to_lisp_function(context,info->si_value.sival_int);
}
void thread_exit_handler(int num, siginfo_t *info, void *v_context)
{ /* called when a child thread exits */
mark_dead_threads();
}
#endif
/* KLUDGE: Theoretically the approach we use for undefined alien
* variables should work for functions as well, but on PPC/Darwin
* we get bus error at bogus addresses instead, hence this workaround,
* that has the added benefit of automatically discriminating between
* functions and variables.
*/
void undefined_alien_function() {
funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
}
boolean handle_guard_page_triggered(os_context_t *context,void *addr){
struct thread *th=arch_os_get_current_thread();
/* note the os_context hackery here. When the signal handler returns,
* it won't go back to what it was doing ... */
if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
/* We hit the end of the control stack: disable guard page
* protection so the error handler has some headroom, protect the
* previous page so that we can catch returns from the guard page
* and restore it. */
protect_control_stack_guard_page(th->pid,0);
protect_control_stack_return_guard_page(th->pid,1);
arrange_return_to_lisp_function
(context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
return 1;
}
else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
/* We're returning from the guard page: reprotect it, and
* unprotect this one. This works even if we somehow missed
* the return-guard-page, and hit it on our way to new
* exhaustion instead. */
protect_control_stack_guard_page(th->pid,1);
protect_control_stack_return_guard_page(th->pid,0);
return 1;
}
else if (addr >= undefined_alien_address &&
addr < undefined_alien_address + os_vm_page_size) {
arrange_return_to_lisp_function
(context, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
return 1;
}
else return 0;
}
#ifndef LISP_FEATURE_GENCGC
/* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
* OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
* whether the signal was due to treading on the mprotect()ed zone -
* and if so, arrange for a GC to happen. */
extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
boolean
interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context)
{
os_context_t *context=(os_context_t *) void_context;
struct thread *th=arch_os_get_current_thread();
struct interrupt_data *data=
th ? th->interrupt_data : global_interrupt_data;
if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){
clear_auto_gc_trigger();
if(!maybe_defer_handler
(interrupt_maybe_gc_int,data,signal,info,void_context))
interrupt_maybe_gc_int(signal,info,void_context);
return 1;
}
return 0;
}
#endif
/* this is also used by gencgc, in alloc() */
boolean
interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context)
{
sigset_t new;
os_context_t *context=(os_context_t *) void_context;
fake_foreign_function_call(context);
/* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
* which case we will be running with no gc trigger barrier
* thing for a while. But it shouldn't be long until the end
* of WITHOUT-GCING. */
sigemptyset(&new);
sigaddset_blockable(&new);
/* enable signals before calling into Lisp */
sigprocmask(SIG_UNBLOCK,&new,0);
funcall0(SymbolFunction(SUB_GC));
undo_fake_foreign_function_call(context);
return 1;
}
/*
* noise to install handlers
*/
void
undoably_install_low_level_interrupt_handler (int signal,
void handler(int,
siginfo_t*,
void*))
{
struct sigaction sa;
struct thread *th=arch_os_get_current_thread();
struct interrupt_data *data=
th ? th->interrupt_data : global_interrupt_data;
if (0 > signal || signal >= NSIG) {
lose("bad signal number %d", signal);
}
sa.sa_sigaction = handler;
sigemptyset(&sa.sa_mask);
sigaddset_blockable(&sa.sa_mask);
sa.sa_flags = SA_SIGINFO | SA_RESTART;
#ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
if((signal==SIG_MEMORY_FAULT)
#ifdef SIG_INTERRUPT_THREAD
|| (signal==SIG_INTERRUPT_THREAD)
#endif
)
sa.sa_flags|= SA_ONSTACK;
#endif
sigaction(signal, &sa, NULL);
data->interrupt_low_level_handlers[signal] =
(ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
}
/* This is called from Lisp. */
unsigned long
install_handler(int signal, void handler(int, siginfo_t*, void*))
{
struct sigaction sa;
sigset_t old, new;
union interrupt_handler oldhandler;
struct thread *th=arch_os_get_current_thread();
struct interrupt_data *data=
th ? th->interrupt_data : global_interrupt_data;
FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
sigemptyset(&new);
sigaddset(&new, signal);
sigprocmask(SIG_BLOCK, &new, &old);
sigemptyset(&new);
sigaddset_blockable(&new);
FSHOW((stderr, "/data->interrupt_low_level_handlers[signal]=%d\n",
data->interrupt_low_level_handlers[signal]));
if (data->interrupt_low_level_handlers[signal]==0) {
if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
ARE_SAME_HANDLER(handler, SIG_IGN)) {
sa.sa_sigaction = handler;
} else if (sigismember(&new, signal)) {
sa.sa_sigaction = maybe_now_maybe_later;
} else {
sa.sa_sigaction = interrupt_handle_now_handler;
}
sigemptyset(&sa.sa_mask);
sigaddset_blockable(&sa.sa_mask);
sa.sa_flags = SA_SIGINFO | SA_RESTART;
sigaction(signal, &sa, NULL);
}
oldhandler = data->interrupt_handlers[signal];
data->interrupt_handlers[signal].c = handler;
sigprocmask(SIG_SETMASK, &old, 0);
FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
return (unsigned long)oldhandler.lisp;
}
void
interrupt_init()
{
int i;
SHOW("entering interrupt_init()");
global_interrupt_data=calloc(sizeof(struct interrupt_data), 1);
/* Set up high level handler information. */
for (i = 0; i < NSIG; i++) {
global_interrupt_data->interrupt_handlers[i].c =
/* (The cast here blasts away the distinction between
* SA_SIGACTION-style three-argument handlers and
* signal(..)-style one-argument handlers, which is OK
* because it works to call the 1-argument form where the
* 3-argument form is expected.) */
(void (*)(int, siginfo_t*, void*))SIG_DFL;
}
SHOW("returning from interrupt_init()");
}