diff options
Diffstat (limited to 'sysdeps/posix/shm_open.c')
-rw-r--r-- | sysdeps/posix/shm_open.c | 85 |
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 |