int bee_flock(char *filename, int operation, int flags)
{
int res;
int fd, fd2;
struct stat statbuf_pre, statbuf_post;
fd = open_and_stat(filename, O_RDONLY|O_CREAT|O_NOCTTY, 0666, &statbuf_pre);
if (fd < 0)
return -1;
while (1) {
res = bee_flock_fd(fd, operation, 0);
if (res < 0)
return -1;
fd2 = open_and_stat(filename, O_RDONLY|O_CREAT|O_NOCTTY, 0666, &statbuf_post);
if (fd2 < 0) {
bee_flock_close(fd);
return -1;
}
if (statbuf_pre.st_ino == statbuf_post.st_ino) {
res = close(fd2);
if (res < 0) {
perror("bee_flock: close");
bee_flock_close(fd);
return -1;
}
return fd;
}
res = bee_flock_close(fd);
if (res < 0) {
res = close(fd2);
if (res < 0)
perror("bee_flock: close");
return -1;
}
fd = fd2;
statbuf_pre = statbuf_post;
}
return -1;
}
int main(int argc, char *argv[])
{
int ret;
int fd;
off_t length;
pid_t pid;
struct stat prev_stat;
if (argc != 3) {
printf("usage: %s path <length>\n", argv[0]);
exit(EXIT_FAILURE);
}
fd = open_and_stat(argv[1], &prev_stat);
if (fd == -1)
exit(EXIT_FAILURE);
length = atoi(argv[2]);
pid = fork();
if (pid == -1) {
perror("fork");
ret = -1;
goto exit;
}
if (pid == 0) {
/* child */
ret = testftruncate(fd, length);
} else {
/* parent */
ret = check_end_child_status(pid);
if (ret)
goto exit;
ret = check_changes(fd, &prev_stat, length);
if (ret)
goto exit;
}
exit:
close_and_exit(fd, ret);
/* never reached */
return 0;
}
