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 *__strchrnul(const char *, int); 10 11char *__shm_mapname(const char *name, char *buf) 12{ 13 char *p; 14 while (*name == '/') name++; 15 if (*(p = __strchrnul(name, '/')) || p==name || 16 (p-name <= 2 && name[0]=='.' && p[-1]=='.')) { 17 errno = EINVAL; 18 return 0; 19 } 20 if (p-name > NAME_MAX) { 21 errno = ENAMETOOLONG; 22 return 0; 23 } 24 memcpy(buf, "/dev/shm/", 9); 25 memcpy(buf+9, name, p-name+1); 26 return buf; 27} 28 29int shm_open(const char *name, int flag, mode_t mode) 30{ 31 int cs; 32 char buf[NAME_MAX+10]; 33 if (!(name = __shm_mapname(name, buf))) return -1; 34 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); 35 int fd = open(name, flag|O_NOFOLLOW|O_CLOEXEC|O_NONBLOCK, mode); 36 pthread_setcancelstate(cs, 0); 37 return fd; 38} 39 40int shm_unlink(const char *name) 41{ 42 char buf[NAME_MAX+10]; 43 if (!(name = __shm_mapname(name, buf))) return -1; 44 return unlink(name); 45} 46