merge trunk

4 files changed, 57 insertions, 92 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 3787e006c4f..56131aca4b2 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -3,6 +3,23 @@
         * coding.c (detect_coding): Set coding->id before calling
         this->detector.
 
+2012-10-13  Andreas Schwab  <schwab@linux-m68k.org>
+
+        * fileio.c: Formatting fixes.
+
+2012-10-13  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Fix some stat-related races.
+        * fileio.c (Fwrite_region): Avoid race condition if a file is
+        removed or renamed by some other process immediately after Emacs
+        writes it but before Emacs stats it.  Do not assume that stat (or
+        fstat) succeeds.
+        * image.c (slurp_file): Resolve the file name with fopen + fstat
+        rather than stat + fopen.
+        (pbm_read_file) [0]: Remove unused code with stat race.
+        * process.c (allocate_pty) [HAVE_PTYS && !PTY_ITERATION && !PTY_OPEN]:
+        Remove ineffective code with stat race.
+
 2012-10-12  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * doc.c (get_doc_string): Don't signal an error if the file is missing.
diff --git a/src/fileio.c b/src/fileio.c
index 5de5bc2b021..e3a91c2c9da 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -1370,8 +1370,7 @@ See also the function `substitute-in-file-name'.")
       p = nm;
       while (*p)
         {
-          if (p[0] == '/' && p[1] == '/'
-              )
+          if (p[0] == '/' && p[1] == '/')
             nm = p + 1;
           if (p[0] == '/' && p[1] == '~')
             nm = p + 1, lose = 1;
@@ -1510,17 +1509,16 @@ search_embedded_absfilename (char *nm, char *endp)
 
   for (p = nm + 1; p < endp; p++)
     {
-      if ((0
-           || IS_DIRECTORY_SEP (p[-1]))
+      if (IS_DIRECTORY_SEP (p[-1])
           && file_name_absolute_p (p)
 #if defined (WINDOWSNT) || defined (CYGWIN)
           /* // at start of file name is meaningful in Apollo,
              WindowsNT and Cygwin systems.  */
           && !(IS_DIRECTORY_SEP (p[0]) && p - 1 == nm)
 #endif /* not (WINDOWSNT || CYGWIN) */
-              )
+          )
         {
-          for (s = p; *s && (!IS_DIRECTORY_SEP (*s)); s++);
+          for (s = p; *s && !IS_DIRECTORY_SEP (*s); s++);
           if (p[0] == '~' && s > p + 1) /* We've got "/~something/".  */
             {
               char *o = alloca (s - p + 1);
@@ -1735,7 +1733,7 @@ those `/' is discarded.  */)
   *x = 0;
 
   /* If /~ or // appears, discard everything through first slash.  */
-  while ((p = search_embedded_absfilename (xnm, x)))
+  while ((p = search_embedded_absfilename (xnm, x)) != NULL)
     /* This time we do not start over because we've already expanded envvars
        and replaced $$ with $.  Maybe we should start over as well, but we'd
        need to quote some $ to $$ first.  */
@@ -2169,7 +2167,7 @@ With a prefix argument, TRASH is nil.  */)
 
   encoded_file = ENCODE_FILE (filename);
 
-  if (0 > unlink (SSDATA (encoded_file)))
+  if (unlink (SSDATA (encoded_file)) < 0)
     report_file_error ("Removing old name", list1 (filename));
   return Qnil;
 }
@@ -2218,8 +2216,8 @@ This is what happens in interactive use with M-x.  */)
 #endif
       )
     {
-      Lisp_Object fname = NILP (Ffile_directory_p (file))
-        ? file : Fdirectory_file_name (file);
+      Lisp_Object fname = (NILP (Ffile_directory_p (file))
+                           ? file : Fdirectory_file_name (file));
       newname = Fexpand_file_name (Ffile_name_nondirectory (fname), newname);
     }
   else
@@ -2247,7 +2245,7 @@ This is what happens in interactive use with M-x.  */)
       || INTEGERP (ok_if_already_exists))
     barf_or_query_if_file_exists (newname, "rename to it",
                                   INTEGERP (ok_if_already_exists), 0, 0);
-  if (0 > rename (SSDATA (encoded_file), SSDATA (encoded_newname)))
+  if (rename (SSDATA (encoded_file), SSDATA (encoded_newname)) < 0)
     {
       if (errno == EXDEV)
         {
@@ -2328,7 +2326,7 @@ This is what happens in interactive use with M-x.  */)
                                   INTEGERP (ok_if_already_exists), 0, 0);
 
   unlink (SSDATA (newname));
-  if (0 > link (SSDATA (encoded_file), SSDATA (encoded_newname)))
+  if (link (SSDATA (encoded_file), SSDATA (encoded_newname)) < 0)
     report_file_error ("Adding new name", list2 (file, newname));
 
   UNGCPRO;
@@ -2385,15 +2383,14 @@ This happens for interactive use with M-x.  */)
       || INTEGERP (ok_if_already_exists))
     barf_or_query_if_file_exists (linkname, "make it a link",
                                   INTEGERP (ok_if_already_exists), 0, 0);
-  if (0 > symlink (SSDATA (encoded_filename),
-                   SSDATA (encoded_linkname)))
+  if (symlink (SSDATA (encoded_filename), SSDATA (encoded_linkname)) < 0)
     {
       /* If we didn't complain already, silently delete existing file.  */
       if (errno == EEXIST)
         {
           unlink (SSDATA (encoded_linkname));
-          if (0 <= symlink (SSDATA (encoded_filename),
-                            SSDATA (encoded_linkname)))
+          if (symlink (SSDATA (encoded_filename), SSDATA (encoded_linkname))
+              >= 0)
             {
               UNGCPRO;
               return Qnil;
@@ -3203,7 +3200,7 @@ emacs_lseek (int fd, EMACS_INT offset, int whence)
 {
   /* Use "&" rather than "&&" to suppress a bogus GCC warning; see
      <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43772>.  */
-  if (! ((TYPE_MINIMUM (off_t) <= offset) & (offset <= TYPE_MAXIMUM (off_t))))
+  if (! ((offset >= TYPE_MINIMUM (off_t)) & (offset <= TYPE_MAXIMUM (off_t))))
     {
       errno = EINVAL;
       return -1;
@@ -3376,7 +3373,7 @@ variable `last-coding-system-used' to the coding system actually used.  */)
 
   if (!NILP (beg))
     {
-      if (! (RANGED_INTEGERP (0, beg, TYPE_MAXIMUM (off_t))))
+      if (! RANGED_INTEGERP (0, beg, TYPE_MAXIMUM (off_t)))
         wrong_type_argument (intern ("file-offset"), beg);
       beg_offset = XFASTINT (beg);
     }
@@ -3385,7 +3382,7 @@ variable `last-coding-system-used' to the coding system actually used.  */)
 
   if (!NILP (end))
     {
-      if (! (RANGED_INTEGERP (0, end, TYPE_MAXIMUM (off_t))))
+      if (! RANGED_INTEGERP (0, end, TYPE_MAXIMUM (off_t)))
         wrong_type_argument (intern ("file-offset"), end);
       end_offset = XFASTINT (end);
     }
@@ -3421,8 +3418,8 @@ variable `last-coding-system-used' to the coding system actually used.  */)
 
       if (beg_offset < likely_end)
         {
-          ptrdiff_t buf_bytes =
-            Z_BYTE - (!NILP (replace) ? ZV_BYTE - BEGV_BYTE  : 0);
+          ptrdiff_t buf_bytes
+            = Z_BYTE - (!NILP (replace) ? ZV_BYTE - BEGV_BYTE  : 0);
           ptrdiff_t buf_growth_max = BUF_BYTES_MAX - buf_bytes;
           off_t likely_growth = likely_end - beg_offset;
           if (buf_growth_max < likely_growth)
@@ -4545,6 +4542,7 @@ This calls `write-region-annotate-functions' at the start, and
   int save_errno = 0;
   const char *fn;
   struct stat st;
+  EMACS_TIME modtime;
   ptrdiff_t count = SPECPDL_INDEX ();
   int count1;
   Lisp_Object handler;
@@ -4757,12 +4755,19 @@ This calls `write-region-annotate-functions' at the start, and
     }
 #endif
 
+  modtime = invalid_emacs_time ();
+  if (visiting)
+    {
+      if (fstat (desc, &st) == 0)
+        modtime = get_stat_mtime (&st);
+      else
+        ok = 0, save_errno = errno;
+    }
+
   /* NFS can report a write failure now.  */
   if (emacs_close (desc) < 0)
     ok = 0, save_errno = errno;
 
-  stat (fn, &st);
-
   /* Discard the unwind protect for close_file_unwind.  */
   specpdl_ptr = specpdl + count1;
 
@@ -4790,9 +4795,9 @@ This calls `write-region-annotate-functions' at the start, and
   /* Do this before reporting IO error
      to avoid a "file has changed on disk" warning on
      next attempt to save.  */
-  if (visiting)
+  if (EMACS_TIME_VALID_P (modtime))
     {
-      current_buffer->modtime = get_stat_mtime (&st);
+      current_buffer->modtime = modtime;
       current_buffer->modtime_size = st.st_size;
     }
 
@@ -5042,12 +5047,12 @@ e_write (int desc, Lisp_Object string, ptrdiff_t start, ptrdiff_t end,
 
       if (coding->produced > 0)
         {
-          coding->produced -=
-            emacs_write (desc,
-                         STRINGP (coding->dst_object)
-                         ? SSDATA (coding->dst_object)
-                         : (char *) BYTE_POS_ADDR (coding->dst_pos_byte),
-                         coding->produced);
+          coding->produced
+            -= emacs_write (desc,
+                            STRINGP (coding->dst_object)
+                            ? SSDATA (coding->dst_object)
+                            : (char *) BYTE_POS_ADDR (coding->dst_pos_byte),
+                            coding->produced);
 
           if (coding->produced)
             return 0;
@@ -5226,8 +5231,8 @@ auto_save_1 (void)
       if (stat (SSDATA (BVAR (current_buffer, filename)), &st) >= 0)
         /* But make sure we can overwrite it later!  */
         auto_save_mode_bits = (st.st_mode | 0600) & 0777;
-      else if ((modes = Ffile_modes (BVAR (current_buffer, filename)),
-                INTEGERP (modes)))
+      else if (modes = Ffile_modes (BVAR (current_buffer, filename)),
+               INTEGERP (modes))
         /* Remote files don't cooperate with stat.  */
         auto_save_mode_bits = (XINT (modes) | 0600) & 0777;
     }
diff --git a/src/image.c b/src/image.c
index 9b41cf74993..d52c3a29a27 100644
--- a/src/image.c
+++ b/src/image.c
@@ -2140,12 +2140,11 @@ x_find_image_file (Lisp_Object file)
 static unsigned char *
 slurp_file (char *file, ptrdiff_t *size)
 {
-  FILE *fp = NULL;
+  FILE *fp = fopen (file, "rb");
   unsigned char *buf = NULL;
   struct stat st;
 
-  if (stat (file, &st) == 0
-      && (fp = fopen (file, "rb")) != NULL
+  if (fp && fstat (fileno (fp), &st) == 0
       && 0 <= st.st_size && st.st_size <= min (PTRDIFF_MAX, SIZE_MAX)
       && (buf = xmalloc (st.st_size),
           fread (buf, 1, st.st_size, fp) == st.st_size))
@@ -5004,45 +5003,6 @@ pbm_scan_number (unsigned char **s, unsigned char *end)
 }
 
 
-#ifdef HAVE_NTGUI
-#if 0  /* Unused. ++kfs  */
-
-/* Read FILE into memory.  Value is a pointer to a buffer allocated
-   with xmalloc holding FILE's contents.  Value is null if an error
-   occurred.  *SIZE is set to the size of the file.  */
-
-static char *
-pbm_read_file (Lisp_Object file, int *size)
-{
-  FILE *fp = NULL;
-  char *buf = NULL;
-  struct stat st;
-
-  if (stat (SDATA (file), &st) == 0
-      && (fp = fopen (SDATA (file), "rb")) != NULL
-      && 0 <= st.st_size && st.st_size <= min (PTRDIFF_MAX, SIZE_MAX)
-      && (buf = xmalloc (st.st_size),
-          fread (buf, 1, st.st_size, fp) == st.st_size))
-    {
-      *size = st.st_size;
-      fclose (fp);
-    }
-  else
-    {
-      if (fp)
-        fclose (fp);
-      if (buf)
-        {
-          xfree (buf);
-          buf = NULL;
-        }
-    }
-
-  return buf;
-}
-#endif
-#endif /* HAVE_NTGUI */
-
 /* Load PBM image IMG for use on frame F.  */
 
 static bool
diff --git a/src/process.c b/src/process.c
index 2cbce9d28ea..d45a2c6e8e0 100644
--- a/src/process.c
+++ b/src/process.c
@@ -646,23 +646,6 @@ allocate_pty (void)
         PTY_OPEN;
 #else /* no PTY_OPEN */
         {
-          { /* Some systems name their pseudoterminals so that there are gaps in
-               the usual sequence - for example, on HP9000/S700 systems, there
-               are no pseudoterminals with names ending in 'f'.  So we wait for
-               three failures in a row before deciding that we've reached the
-               end of the ptys.  */
-            int failed_count = 0;
-            struct stat stb;
-
-            if (stat (pty_name, &stb) < 0)
-              {
-                failed_count++;
-                if (failed_count >= 3)
-                  return -1;
-              }
-            else
-              failed_count = 0;
-          }
 #  ifdef O_NONBLOCK
           fd = emacs_open (pty_name, O_RDWR | O_NONBLOCK, 0);
 #  else