about summary refs log tree commit diff
path: root/sysdeps/posix/shm_open.c
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/posix/shm_open.c')
-rw-r--r--sysdeps/posix/shm_open.c85
1 files changed, 85 insertions, 0 deletions
diff --git a/sysdeps/posix/shm_open.c b/sysdeps/posix/shm_open.c
new file mode 100644
index 0000000000..8b8f87592d
--- /dev/null
+++ b/sysdeps/posix/shm_open.c
@@ -0,0 +1,85 @@
+/* shm_open -- open a POSIX shared memory object.  Generic POSIX file version.
+   Copyright (C) 2001 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
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <unistd.h>
+
+#if ! _POSIX_MAPPED_FILES
+#include <sysdeps/generic/shm_open.c>
+
+#else
+
+#include <errno.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <paths.h>
+
+#define SHMDIR	(_PATH_VARRUN "shm/")
+
+/* Open shared memory object.  */
+int
+shm_open (const char *name, int oflag, mode_t mode)
+{
+  size_t namelen;
+  char *fname;
+  int fd;
+
+  /* Construct the filename.  */
+  while (name[0] == '/')
+    ++name;
+
+  if (name[0] == '\0')
+    {
+      /* The name "/" is not supported.  */
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  namelen = strlen (name);
+  fname = (char *) __alloca (sizeof SHMDIR - 1 + namelen + 1);
+  __mempcpy (__mempcpy (fname, SHMDIR, sizeof SHMDIR - 1),
+	     name, namelen + 1);
+
+  fd = open (name, oflag, 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) != -1)
+	{
+	  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);
+	}
+    }
+
+  return fd;
+}
+
+#endif