[Valgrind-developers] Valgrind: r14210 - in /branches/BUF_REMOVAL: coregrind/m_coredump/coredump-elf.c coregrind/m_debuginfo/debuginfo.c coregrind/m_libcfile.c coregrind/m_syswrap/syswrap-generic.c coregrind/pub_core_libcfile.h include/pub_tool_libcfile.h

[<sv...@va...>]

Author: florian
Date: Wed Jul 30 14:24:10 2014
New Revision: 14210

Log:
Change VG_(readlink) and VG_(resolve_filename) to return pointer to
dynamically allocated string which will be overwritten with each 
invocation. Fix call sites.

Modified:
    branches/BUF_REMOVAL/coregrind/m_coredump/coredump-elf.c
    branches/BUF_REMOVAL/coregrind/m_debuginfo/debuginfo.c
    branches/BUF_REMOVAL/coregrind/m_libcfile.c
    branches/BUF_REMOVAL/coregrind/m_syswrap/syswrap-generic.c
    branches/BUF_REMOVAL/coregrind/pub_core_libcfile.h
    branches/BUF_REMOVAL/include/pub_tool_libcfile.h

Modified: branches/BUF_REMOVAL/coregrind/m_coredump/coredump-elf.c
==============================================================================
--- branches/BUF_REMOVAL/coregrind/m_coredump/coredump-elf.c (original)
+++ branches/BUF_REMOVAL/coregrind/m_coredump/coredump-elf.c Wed Jul 30 14:24:10 2014
@@ -193,7 +193,7 @@
 static void fill_prpsinfo(const ThreadState *tst,
                           struct vki_elf_prpsinfo *prpsinfo)
 {
-   static HChar name[VKI_PATH_MAX];
+   HChar *name;
 
    VG_(memset)(prpsinfo, 0, sizeof(*prpsinfo));
 
@@ -220,7 +220,7 @@
    prpsinfo->pr_uid = 0;
    prpsinfo->pr_gid = 0;
    
-   if (VG_(resolve_filename)(VG_(cl_exec_fd), name, VKI_PATH_MAX)) {
+   if (VG_(resolve_filename)(VG_(cl_exec_fd), &name)) {
       HChar *n = name+VG_(strlen)(name)-1;
 
       while (n > name && *n != '/')

Modified: branches/BUF_REMOVAL/coregrind/m_debuginfo/debuginfo.c
==============================================================================
--- branches/BUF_REMOVAL/coregrind/m_debuginfo/debuginfo.c (original)
+++ branches/BUF_REMOVAL/coregrind/m_debuginfo/debuginfo.c Wed Jul 30 14:24:10 2014
@@ -1090,7 +1090,6 @@
 {
    Int    i, r, sz_exename;
    ULong  obj_mtime, pdb_mtime;
-   HChar  exename[VKI_PATH_MAX];
    HChar* pdbname = NULL;
    HChar* dot;
    SysRes sres;
@@ -1111,21 +1110,23 @@
       time into obj_mtime. */
    r = VG_(fstat)(fd_obj, &stat_buf);
    if (r == -1)
-      goto out; /* stat failed ?! */
+      return; /* stat failed ?! */
    vg_assert(r == 0);
    obj_mtime = stat_buf.mtime;
 
-   /* and get its name into exename[]. */
-   vg_assert(VKI_PATH_MAX > 100); /* to ensure /proc/self/fd/%d is safe */
-   VG_(memset)(exename, 0, sizeof(exename));
-   VG_(sprintf)(exename, "/proc/self/fd/%d", fd_obj);
-   /* convert exename from a symlink to real name .. overwrites the
-      old contents of the buffer.  Ick. */
-   sz_exename = VG_(readlink)(exename, exename, sizeof(exename)-2 );
+   /* and get its name into exename. */
+   HChar tmp[64];   // large enough
+   VG_(sprintf)(tmp, "/proc/self/fd/%d", fd_obj);
+
+   /* convert tmp from a symlink to real name */
+   HChar *exe;
+   sz_exename = VG_(readlink)(tmp, &exe);
+
    if (sz_exename == -1)
-      goto out; /* readlink failed ?! */
-   vg_assert(sz_exename >= 0 && sz_exename < sizeof(exename));
-   vg_assert(exename[sizeof(exename)-1] == 0);
+      return; /* readlink failed ?! */
+
+   HChar exename[sz_exename + 1];
+   VG_(strcpy)(exename, exe);  // make a copy on the stack 
 
    if (VG_(clo_verbosity) > 0) {
       VG_(message)(Vg_UserMsg, "LOAD_PDB_DEBUGINFO: objname: %s\n", exename);

Modified: branches/BUF_REMOVAL/coregrind/m_libcfile.c
==============================================================================
--- branches/BUF_REMOVAL/coregrind/m_libcfile.c (original)
+++ branches/BUF_REMOVAL/coregrind/m_libcfile.c Wed Jul 30 14:24:10 2014
@@ -70,14 +70,18 @@
 
 /* Given a file descriptor, attempt to deduce its filename.  To do
    this, we use /proc/self/fd/<FD>.  If this doesn't point to a file,
-   or if it doesn't exist, we return False. */
-Bool VG_(resolve_filename) ( Int fd, HChar* buf, Int n_buf )
+   or if it doesn't exist, we return False. 
+   Upon successful completion *result contains the filename. The
+   filename will be overwritten with the next invocation so callers
+   need to copy the filename if needed. *result is NULL if the filename
+   cannot be deduced. */
+Bool VG_(resolve_filename) ( Int fd, HChar** result )
 {
 #  if defined(VGO_linux)
-   HChar tmp[64];
+   HChar tmp[64];   // large enough
    VG_(sprintf)(tmp, "/proc/self/fd/%d", fd);
-   VG_(memset)(buf, 0, n_buf);
-   if (VG_(readlink)(tmp, buf, n_buf) > 0 && buf[0] == '/')
+
+   if (VG_(readlink)(tmp, result) > 0 && (*result)[0] == '/')
       return True;
    else
       return False;
@@ -85,12 +89,16 @@
 #  elif defined(VGO_darwin)
    HChar tmp[VKI_MAXPATHLEN+1];
    if (0 == VG_(fcntl)(fd, VKI_F_GETPATH, (UWord)tmp)) {
-      if (n_buf > 0) {
-         VG_(strncpy)( buf, tmp, n_buf < sizeof(tmp) ? n_buf : sizeof(tmp) );
-         buf[n_buf-1] = 0;
-      }
-      if (tmp[0] == '/') return True;
+      static HChar *buf = NULL;
+
+      if (buf == NULL) 
+         buf = VG_(arena_malloc)(VG_AR_CORE, VKI_MAXPATHLEN+1);
+      VG_(strcpy)( buf, tmp );
+
+      *result = buf;
+      if (result[0] == '/') return True;
    }
+   *result = NULL;
    return False;
 
 #  else
@@ -507,17 +515,51 @@
 }
 
 
-Int VG_(readlink) (const HChar* path, HChar* buf, UInt bufsiz)
+/* Perform the readlink operation on path. Upon successful completion
+   *result points to a dynamically allocated buffer that contains the
+   untruncated contents of the symbolic link. The string is properly
+   terminated with '\0'. The return value is the number of characters
+   written to that buffer not counting the terminating '\0' character.
+   This buffer will be overwritten in the next invocation so callers
+   need to copy the result if needed.
+   If the operation fails, the function returns -1 and *result is NULL. */
+Int VG_(readlink) (const HChar* path, HChar** result)
 {
    SysRes res;
-   /* res = readlink( path, buf, bufsiz ); */
+   static HChar *buf = NULL;
+   static UInt bufsiz = 0;
+
+   if (buf == NULL) {          // 1st time
+      bufsiz = VKI_PATH_MAX;
+      buf = VG_(arena_malloc)(VG_AR_CORE, "readlink", bufsiz);
+   }
+
+   while (42) {
 #  if defined(VGP_arm64_linux)
-   res = VG_(do_syscall4)(__NR_readlinkat, VKI_AT_FDCWD,
+      res = VG_(do_syscall4)(__NR_readlinkat, VKI_AT_FDCWD,
                                            (UWord)path, (UWord)buf, bufsiz);
 #  else
-   res = VG_(do_syscall3)(__NR_readlink, (UWord)path, (UWord)buf, bufsiz);
+      res = VG_(do_syscall3)(__NR_readlink, (UWord)path, (UWord)buf, bufsiz);
 #  endif
-   return sr_isError(res) ? -1 : sr_Res(res);
+      if (sr_isError(res)) {
+         *result = NULL;
+         return -1;
+      }
+      UInt num_char_written = sr_Res(res);
+
+      if (num_char_written == bufsiz) {
+         // Buffer was too small. Increase size and retry.
+         bufsiz += VKI_PATH_MAX;
+         buf = VG_(arena_realloc)(VG_AR_CORE, "readlink", buf, bufsiz);
+         continue;
+      }
+
+      vg_assert(num_char_written < bufsiz);    // paranoia
+
+      buf[num_char_written] = '\0';    // properly terminate
+      *result = buf;
+      return num_char_written;
+   }
 }
 
 Int VG_(getdents) (Int fd, struct vki_dirent *dirp, UInt count)

Modified: branches/BUF_REMOVAL/coregrind/m_syswrap/syswrap-generic.c
==============================================================================
--- branches/BUF_REMOVAL/coregrind/m_syswrap/syswrap-generic.c (original)
+++ branches/BUF_REMOVAL/coregrind/m_syswrap/syswrap-generic.c Wed Jul 30 14:24:10 2014
@@ -591,9 +591,9 @@
 // Record opening of an fd, and find its name.
 void ML_(record_fd_open_named)(ThreadId tid, Int fd)
 {
-   static HChar buf[VKI_PATH_MAX];
+   HChar* buf;
    HChar* name;
-   if (VG_(resolve_filename)(fd, buf, VKI_PATH_MAX))
+   if (VG_(resolve_filename)(fd, &buf))
       name = buf;
    else
       name = NULL;

Modified: branches/BUF_REMOVAL/coregrind/pub_core_libcfile.h
==============================================================================
--- branches/BUF_REMOVAL/coregrind/pub_core_libcfile.h (original)
+++ branches/BUF_REMOVAL/coregrind/pub_core_libcfile.h Wed Jul 30 14:24:10 2014
@@ -44,7 +44,7 @@
 extern Int VG_(fcntl)   ( Int fd, Int cmd, Addr arg );
 
 /* Convert an fd into a filename */
-extern Bool VG_(resolve_filename) ( Int fd, HChar* buf, Int n_buf );
+extern Bool VG_(resolve_filename) ( Int fd, HChar** buf );
 
 /* Return the size of a file, or -1 in case of error */
 extern Long VG_(fsize) ( Int fd );

Modified: branches/BUF_REMOVAL/include/pub_tool_libcfile.h
==============================================================================
--- branches/BUF_REMOVAL/include/pub_tool_libcfile.h (original)
+++ branches/BUF_REMOVAL/include/pub_tool_libcfile.h Wed Jul 30 14:24:10 2014
@@ -91,7 +91,7 @@
 
 extern SysRes VG_(poll) (struct vki_pollfd *fds, Int nfds, Int timeout);
 
-extern Int    VG_(readlink)( const HChar* path, HChar* buf, UInt bufsize );
+extern Int    VG_(readlink)( const HChar* path, HChar** buf );
 extern Int    VG_(getdents)( Int fd, struct vki_dirent *dirp, UInt count );
 
 extern const HChar* VG_(basename)( const HChar* path );