(shm_open): Use O_CLOEXEC is available.

diff --git a/sysdeps/unix/sysv/linux/shm_open.c b/sysdeps/unix/sysv/linux/shm_open.c
index 0d40632..0628427 100644 (file)
--- a/sysdeps/unix/sysv/linux/shm_open.c
+++ b/sysdeps/unix/sysv/linux/shm_open.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2000,2001,2002,2003,2004,2006 Free Software Foundation, Inc.
+/* Copyright (C) 2000-2004,2006,2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -46,6 +46,11 @@ static const char defaultdir[] = "/dev/shm/";
 __libc_once_define (static, once);
 
 
+#if defined O_CLOEXEC && !defined __ASSUME_O_CLOEXEC
+static bool have_o_cloexec;
+#endif
+
+
 /* Determine where the shmfs is mounted (if at all).  */
 static void
 where_is_shmfs (void)
@@ -160,6 +165,10 @@ shm_open (const char *name, int oflag, mode_t mode)
   __mempcpy (__mempcpy (fname, mountpoint.dir, mountpoint.dirlen),
             name, namelen + 1);
 
+#ifdef O_CLOEXEC
+  oflag |= O_CLOEXEC;
+#endif
+
   /* And get the file descriptor.
      XXX Maybe we should test each descriptor whether it really is for a
      file on the shmfs.  If this is what should be done the whole function
@@ -168,23 +177,37 @@ shm_open (const char *name, int oflag, mode_t mode)
   fd = open (fname, oflag | O_NOFOLLOW, mode);
   if (fd != -1)
     {
-      /* We got a descriptor.  Now set the FD_CLOEXEC bit.  */
-      int flags = fcntl (fd, F_GETFD, 0);
-
-      if (__builtin_expect (flags, 0) >= 0)
+#if !defined O_CLOEXEC || !defined __ASSUME_O_CLOEXEC
+# ifdef O_CLOEXEC
+      if (have_o_cloexec <= 0)
+# endif
        {
-         flags |= FD_CLOEXEC;
-         flags = fcntl (fd, F_SETFD, flags);
-       }
-
-      if (flags == -1)
-       {
-         /* Something went wrong.  We cannot return the descriptor.  */
-         int save_errno = errno;
-         close (fd);
-         fd = -1;
-         __set_errno (save_errno);
+         /* We got a descriptor.  Now set the FD_CLOEXEC bit.  */
+         int flags = fcntl (fd, F_GETFD, 0);
+
+         if (__builtin_expect (flags, 0) >= 0)
+           {
+# ifndef O_CLOEXEC
+             if (have_o_cloexec == 0)
+               have_o_cloexec = (flags & FD_CLOEXEC) == 0 ? -1 : 1;
+             if (have_o_cloexec < 0)
+# endif
+               {
+                 flags |= FD_CLOEXEC;
+                 flags = fcntl (fd, F_SETFD, flags);
+               }
+           }
+
+         if (flags == -1)
+           {
+             /* Something went wrong.  We cannot return the descriptor.  */
+             int save_errno = errno;
+             close (fd);
+             fd = -1;
+             __set_errno (save_errno);
+           }
        }
+#endif
     }
   else if (__builtin_expect (errno == EISDIR, 0))
     /* It might be better to fold this error with EINVAL since