glibc/sysdeps/posix/shm_open.c
Roland McGrath 221dc560bb * sysdeps/mach/hurd/fork.c (LOSE): Put `goto lose' in dead code
so the label is not considered unused.

	* sysdeps/mach/hurd/pwrite64.c: New file.
	* sysdeps/mach/hurd/pread64.c: New file.

	* sysdeps/mach/hurd/pread.c
	(__libc_pread): Define this name, with __pread as an alias.
	* sysdeps/mach/hurd/pwrite.c
	(__libc_pwrite): Define this name, with __pwrite as an alias.

	Implement POSIX "shared memory objects" as regular
	files residing in the /var/run/shm/ directory.
	This works on any system that supports _POSIX_MAPPED_FILES,
	to make it also support _POSIX_SHARED_MEMORY_OBJECTS.
	* sysdeps/posix/shm_open.c: New file.
	* sysdeps/posix/shm_unlink.c: New file.
	* sysdeps/mach/hurd/bits/posix_opt.h
	(_POSIX_SHARED_MEMORY_OBJECTS): Define it.

	* rt/aio_notify.c (__aio_notify_only) [! _POSIX_REALTIME_SIGNALS]:
	Use raise instead of __aio_sigqueue.
2001-06-14 05:32:26 +00:00

86 lines
2.2 KiB
C

/* 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