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/* shm_open -- open a POSIX shared memory object. Generic POSIX file version.
Copyright (C) 2001-2017 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <unistd.h>
#if ! _POSIX_MAPPED_FILES
# include <rt/shm_open.c>
#else
# include <fcntl.h>
# include <shm-directory.h>
/* Open shared memory object. */
int
shm_open (const char *name, int oflag, mode_t mode)
{
SHM_GET_NAME (EINVAL, -1, "");
# ifdef O_NOFOLLOW
oflag |= O_NOFOLLOW;
# endif
# ifdef O_CLOEXEC
oflag |= O_CLOEXEC;
# endif
/* Disable asynchronous cancellation. */
int state;
pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
int fd = open (shm_name, oflag, mode);
if (fd == -1 && __glibc_unlikely (errno == EISDIR))
/* It might be better to fold this error with EINVAL since
directory names are just another example for unsuitable shared
object names and the standard does not mention EISDIR. */
__set_errno (EINVAL);
# ifndef O_CLOEXEC
if (fd != -1)
{
/* We got a descriptor. Now set the FD_CLOEXEC bit. */
int flags = fcntl (fd, F_GETFD, 0);
if (__glibc_likely (flags != -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);
}
}
# endif
pthread_setcancelstate (state, NULL);
return fd;
}
#endif /* _POSIX_MAPPED_FILES */
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