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/* Copyright (C) 2009 Bernhard Reutner-Fischer <uclibc@uclibc.org>
*
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
#include <features.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#ifndef _PATH_SHM
#define _PATH_SHM "/dev/shm/"
#endif
#ifndef NAME_MAX
#define NAME_MAX 255
#endif
/* Get name of dummy shm operation handle.
* Returns a malloc'ed buffer containing the OS specific path
* to the shm filename or NULL upon failure.
*/
static __attribute_noinline__ char* get_shm_name(const char*name) __nonnull((1));
static char* get_shm_name(const char*name)
{
char *path;
int i;
/* Skip leading slashes */
while (*name == '/')
++name;
#ifdef __USE_GNU
i = asprintf(&path, _PATH_SHM "%s", name);
if (i < 0)
return NULL;
#else
path = malloc(NAME_MAX);
if (path == NULL)
return NULL;
i = snprintf(path, NAME_MAX, _PATH_SHM "%s", name);
if (i < 0) {
free(path);
return NULL;
} else if (i >= NAME_MAX) {
free(path);
__set_errno(ENAMETOOLONG);
return NULL;
}
#endif
return path;
}
int shm_open(const char *name, int oflag, mode_t mode)
{
int fd, old_errno;
char *shm_name = get_shm_name(name);
/* Stripped multiple '/' from start; may have set errno properly */
if (shm_name == NULL)
return -1;
/* The FD_CLOEXEC file descriptor flag associated with the new
* file descriptor is set. */
#ifdef O_CLOEXEC
/* Just open it with CLOEXEC set, for brevity */
fd = open(shm_name, oflag | O_CLOEXEC, mode);
#else
fd = open(shm_name, oflag, mode);
if (fd >= 0) {
fcntl(fd, F_SETFD, FD_CLOEXEC);
// thus far, {G,S}ETFD only has this single flag,
// and setting it never fails.
//int fdflags = fcntl(fd, F_GETFD);
//if (fdflags >= 0)
// fdflags = fcntl(fd, F_SETFD, fdflags | FD_CLOEXEC);
//if (fdflags < 0) {
// close(fd);
// fd = -1;
//}
}
#endif
old_errno = errno;
free(shm_name);
errno = old_errno;
return fd;
}
int shm_unlink(const char *name)
{
char *shm_name = get_shm_name(name);
int ret, old_errno;
/* Stripped multiple '/' from start; may have set errno properly */
if (shm_name == NULL)
return -1;
ret = unlink(shm_name);
old_errno = errno;
free(shm_name);
errno = old_errno;
return ret;
}
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