bug#15015: Fix some minor races in hosts lacking mkostemp

[Paul Eggert]

On 08/04/2013 08:44 AM, Eli Zaretskii wrote:
> So I went ahead and implemented mkostemp for MS-Windows (trunk
> revision 113687).  I also removed sys_mktemp, as it is no longer
> needed.

Thanks, that should do it on the Microsoft side.  I installed
the patch and am marking this done.  The patch I installed
also included the following additional simplification:

=== modified file 'ChangeLog'
--- ChangeLog   2013-08-04 01:23:59 +0000
+++ ChangeLog   2013-08-04 16:52:55 +0000
@@ -2,6 +2,9 @@
 
        Fix some minor races in hosts lacking mkostemp (Bug#15015).
        Gnulib's emulation of mkostemp doesn't have races that Emacs's does.
+       * configure.ac (mkostemp): Remove check for this function;
+       gnulib does the check now.
+       (mkstemp): Remove check for this no-longer-used function.
        * lib/mkostemp.c, lib/secure_getenv.c, lib/tempname.c, lib/tempname.h:
        * m4/mkostemp.m4, m4/secure_getenv.m4, m4/tempname.m4:
        New files, copied from Gnulib.

=== modified file 'configure.ac'
--- configure.ac        2013-07-27 01:18:21 +0000
+++ configure.ac        2013-08-04 16:52:25 +0000
@@ -3277,7 +3277,7 @@
 getrlimit setrlimit shutdown getaddrinfo \
 strsignal setitimer \
 sendto recvfrom getsockname getpeername getifaddrs freeifaddrs \
-gai_strerror mkostemp mkstemp getline getdelim sync \
+gai_strerror getline getdelim sync \
 difftime posix_memalign \
 getpwent endpwent getgrent endgrent \
 touchlock \

=== modified file 'lib-src/ChangeLog'
--- lib-src/ChangeLog   2013-07-10 23:23:57 +0000
+++ lib-src/ChangeLog   2013-08-04 16:48:02 +0000
@@ -1,3 +1,12 @@
+2013-08-04  Paul Eggert  <eggert@cs.ucla.edu>
+
+       Fix some minor races in hosts lacking mkostemp (Bug#15015).
+       * movemail.c (main):
+       * update-game-score.c (write_scores):
+       Use mkostemp (which now works on all platforms, due to changes
+       in the portability layer) rather than mktemp (which has a race)
+       or mkstemp (which we no longer bother with).
+
 2013-07-10  Paul Eggert  <eggert@cs.ucla.edu>
 
        Port to C89.

=== modified file 'lib-src/movemail.c'
--- lib-src/movemail.c  2013-03-13 18:42:22 +0000
+++ lib-src/movemail.c  2013-08-04 16:35:45 +0000
@@ -304,24 +304,13 @@
 
          memcpy (tempname, inname, inname_dirlen);
          strcpy (tempname + inname_dirlen, "EXXXXXX");
-#ifdef HAVE_MKSTEMP
-         desc = mkstemp (tempname);
-#else
-         mktemp (tempname);
-         if (!*tempname)
-           desc = -1;
-         else
-           {
-             unlink (tempname);
-             desc = open (tempname, O_WRONLY | O_CREAT | O_EXCL, 0600);
-           }
-#endif
+         desc = mkostemp (tempname, 0);
          if (desc < 0)
            {
-             int mkstemp_errno = errno;
+             int mkostemp_errno = errno;
              error ("error while creating what would become the lock file",
                     0, 0);
-             errno = mkstemp_errno;
+             errno = mkostemp_errno;
              pfatal_with_name (tempname);
            }
          close (desc);

=== modified file 'lib-src/update-game-score.c'
--- lib-src/update-game-score.c 2013-03-30 17:00:51 +0000
+++ lib-src/update-game-score.c 2013-08-04 16:28:47 +0000
@@ -383,6 +383,7 @@
 static int
 write_scores (const char *filename, const struct score_entry *scores, int 
count)
 {
+  int fd;
   FILE *f;
   int i;
   char *tempfile = malloc (strlen (filename) + strlen (".tempXXXXXX") + 1);
@@ -390,12 +391,11 @@
     return -1;
   strcpy (tempfile, filename);
   strcat (tempfile, ".tempXXXXXX");
-#ifdef HAVE_MKSTEMP
-  if (mkstemp (tempfile) < 0
-#else
-  if (mktemp (tempfile) != tempfile
-#endif
-      || !(f = fopen (tempfile, "w")))
+  fd = mkostemp (tempfile, 0);
+  if (fd < 0)
+    return -1;
+  f = fdopen (fd, "w");
+  if (! f)
     return -1;
   for (i = 0; i < count; i++)
     if (fprintf (f, "%ld %s %s\n", scores[i].score, scores[i].username,