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#include <sys/mman.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <limits.h>
#include <pthread.h>
char *__strchrnul(const char *, int);
char *__shm_mapname(const char *name, char *buf)
{
char *p;
while (*name == '/') name++;
if (*(p = __strchrnul(name, '/')) || p==name ||
(p-name <= 2 && name[0]=='.' && p[-1]=='.')) {
errno = EINVAL;
return 0;
}
if (p-name > NAME_MAX) {
errno = ENAMETOOLONG;
return 0;
}
memcpy(buf, "/dev/shm/", 9);
memcpy(buf+9, name, p-name+1);
return buf;
}
int shm_open(const char *name, int flag, mode_t mode)
{
int cs;
char buf[NAME_MAX+10];
if (!(name = __shm_mapname(name, buf))) return -1;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
int fd = open(name, flag|O_NOFOLLOW|O_CLOEXEC|O_NONBLOCK, mode);
pthread_setcancelstate(cs, 0);
return fd;
}
int shm_unlink(const char *name)
{
char buf[NAME_MAX+10];
if (!(name = __shm_mapname(name, buf))) return -1;
return unlink(name);
}
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