1#include <sys/mman.h>
 2#include <errno.h>
 3#include <fcntl.h>
 4#include <unistd.h>
 5#include <string.h>
 6#include <limits.h>
 7#include <pthread.h>
 8
 9char *__shm_mapname(const char *name, char *buf)
10{
11	char *p;
12	while (*name == '/') name++;
13	if (*(p = __strchrnul(name, '/')) || p==name ||
14	    (p-name <= 2 && name[0]=='.' && p[-1]=='.')) {
15		errno = EINVAL;
16		return 0;
17	}
18	if (p-name > NAME_MAX) {
19		errno = ENAMETOOLONG;
20		return 0;
21	}
22	memcpy(buf, "/dev/shm/", 9);
23	memcpy(buf+9, name, p-name+1);
24	return buf;
25}
26
27int shm_open(const char *name, int flag, mode_t mode)
28{
29	int cs;
30	char buf[NAME_MAX+10];
31	if (!(name = __shm_mapname(name, buf))) return -1;
32	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
33	int fd = open(name, flag|O_NOFOLLOW|O_CLOEXEC|O_NONBLOCK, mode);
34	pthread_setcancelstate(cs, 0);
35	return fd;
36}
37
38int shm_unlink(const char *name)
39{
40	char buf[NAME_MAX+10];
41	if (!(name = __shm_mapname(name, buf))) return -1;
42	return unlink(name);
43}