mirror of
https://sourceware.org/git/glibc.git
synced 2025-11-03 20:53:13 +03:00
e9fed2438a
Previously, glibc would pick an arbitrary tmpfs file system from /proc/mounts if /dev/shm was not available. This could lead to an unsuitable file system being picked for the backing storage for shm_open, sem_open, and related functions. This patch introduces a new function, __shm_get_name, which builds the file name under the appropriate (now hard-coded) directory. It is called from the various shm_* and sem_* function. Unlike the SHM_GET_NAME macro it replaces, the callers handle the return values and errno updates. shm-directory.c is moved directly into the posix subdirectory because it can be implemented directly using POSIX functionality. It resides in libc because it is needed by both librt and nptl/htl. In the sem_open implementation, tmpfname is initialized directly from a string constant. This happens to remove one alloca call. Checked on x86_64-linux-gnu.
63 lines
1.8 KiB
C
63 lines
1.8 KiB
C
/* shm_open -- open a POSIX shared memory object. Generic POSIX file version.
|
|
Copyright (C) 2001-2021 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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <unistd.h>
|
|
|
|
#if ! _POSIX_MAPPED_FILES
|
|
|
|
# include <rt/shm_open.c>
|
|
|
|
#else
|
|
|
|
# include <errno.h>
|
|
# include <fcntl.h>
|
|
# include <pthread.h>
|
|
# include <shm-directory.h>
|
|
|
|
|
|
/* Open shared memory object. */
|
|
int
|
|
shm_open (const char *name, int oflag, mode_t mode)
|
|
{
|
|
struct shmdir_name dirname;
|
|
if (__shm_get_name (&dirname, name, false) != 0)
|
|
{
|
|
__set_errno (EINVAL);
|
|
return -1;
|
|
}
|
|
|
|
oflag |= O_NOFOLLOW | O_CLOEXEC;
|
|
|
|
/* Disable asynchronous cancellation. */
|
|
int state;
|
|
pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
|
|
|
|
int fd = open (dirname.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);
|
|
|
|
pthread_setcancelstate (state, NULL);
|
|
|
|
return fd;
|
|
}
|
|
|
|
#endif /* _POSIX_MAPPED_FILES */
|