Set close-on-exec flag when opening files.

2013-11-10  Janne Blomqvist  <jb@gcc.gnu.org>

	* configure.ac: Check presence of mkostemp.
	* io/unix.c (set_close_on_exec): New function.
	(tempfile_open): Use mkostemp and O_CLOEXEC if available, fallback
	to calling set_close_on_exec.
	(regular_file): Add O_CLOEXEC to flags if defined.
	(open_external): Call set_close_on_exec if O_CLOEXEC is not
	defined.
	* config.h.in: Regenerated.
	* configure: Regenerated.
	* Makefile.in: Regenerated.
	* aclocal.m4: Regenerated.

From-SVN: r204654

1 files changed, 37 insertions, 6 deletions

diff --git a/libgfortran/io/unix.c b/libgfortran/io/unix.c
index dd2715b..8a84ae4 100644
--- a/libgfortran/io/unix.c
+++ b/libgfortran/io/unix.c
@@ -1070,6 +1070,20 @@ unpack_filename (char *cstring, const char *fstring, int len)
 }
 
 
+/* Set the close-on-exec flag for an existing fd, if the system
+   supports such.  */
+
+static void __attribute__ ((unused))
+set_close_on_exec (int fd __attribute__ ((unused)))
+{
+  /* Mingw does not define F_SETFD.  */
+#if defined(F_SETFD) && defined(FD_CLOEXEC)
+  if (fd >= 0)
+    fcntl(fd, F_SETFD, FD_CLOEXEC);
+#endif
+}
+
+
 /* Helper function for tempfile(). Tries to open a temporary file in
    the directory specified by tempdir. If successful, the file name is
    stored in fname and the descriptor returned. Returns -1 on
@@ -1109,7 +1123,12 @@ tempfile_open (const char *tempdir, char **fname)
   mode_mask = umask (S_IXUSR | S_IRWXG | S_IRWXO);
 #endif
 
+#if defined(HAVE_MKOSTEMP) && defined(O_CLOEXEC)
+  fd = mkostemp (template, O_RDWR | O_CREAT | O_EXCL | O_CLOEXEC);
+#else
   fd = mkstemp (template);
+  set_close_on_exec (fd);
+#endif
 
 #ifdef HAVE_UMASK
   (void) umask (mode_mask);
@@ -1119,6 +1138,13 @@ tempfile_open (const char *tempdir, char **fname)
   fd = -1;
   int count = 0;
   size_t slashlen = strlen (slash);
+  int flags = O_RDWR | O_CREAT | O_EXCL;
+#if defined(HAVE_CRLF) && defined(O_BINARY)
+  flags |= O_BINARY;
+#endif
+#ifdef O_CLOEXEC
+  flags |= O_CLOEXEC;
+#endif
   do
     {
       snprintf (template, tempdirlen + 23, "%s%sgfortrantmpaaaXXXXXX", 
@@ -1142,14 +1168,12 @@ tempfile_open (const char *tempdir, char **fname)
 	continue;
       }
 
-#if defined(HAVE_CRLF) && defined(O_BINARY)
-      fd = open (template, O_RDWR | O_CREAT | O_EXCL | O_BINARY,
-		 S_IRUSR | S_IWUSR);
-#else
-      fd = open (template, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
-#endif
+      fd = open (template, flags, S_IRUSR | S_IWUSR);
     }
   while (fd == -1 && errno == EEXIST);
+#ifndef O_CLOEXEC
+  set_close_on_exec (fd);
+#endif
 #endif /* HAVE_MKSTEMP */
 
   *fname = template;
@@ -1323,6 +1347,10 @@ regular_file (st_parameter_open *opp, unit_flags *flags)
   crflag |= O_BINARY;
 #endif
 
+#ifdef O_CLOEXEC
+  crflag |= O_CLOEXEC;
+#endif
+
   mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
   fd = open (path, rwflag | crflag, mode);
   if (flags->action != ACTION_UNSPECIFIED)
@@ -1386,6 +1414,9 @@ open_external (st_parameter_open *opp, unit_flags *flags)
       /* regular_file resets flags->action if it is ACTION_UNSPECIFIED and
        * if it succeeds */
       fd = regular_file (opp, flags);
+#ifndef O_CLOEXEC
+      set_close_on_exec (fd);
+#endif
     }
 
   if (fd < 0)