Function create_pid_file

clientserver.c:1448–1498

}

static void create_pid_file(void)
{
	char *pid_file = lp_pid_file();
	char pidbuf[32];
	STRUCT_STAT st1, st2;
	char *fail = NULL;

	if (!pid_file || !*pid_file)
		return;

#ifdef O_NOFOLLOW
#define SAFE_OPEN_FLAGS (O_CREAT|O_NOFOLLOW)
#else
#define SAFE_OPEN_FLAGS (O_CREAT)
#endif

	/* These tests make sure that a temp-style lock dir is handled safely. */
	st1.st_mode = 0;
	if (do_lstat(pid_file, &st1) == 0 && !S_ISREG(st1.st_mode) && unlink(pid_file) < 0)
		fail = "unlink";
	else if ((pid_file_fd = do_open(pid_file, O_RDWR|SAFE_OPEN_FLAGS, 0664)) < 0)
		fail = S_ISREG(st1.st_mode) ? "open" : "create";
	else if (!lock_range(pid_file_fd, 0, 4))
		fail = "lock";
	else if (do_fstat(pid_file_fd, &st1) < 0)
		fail = "fstat opened";
	else if (st1.st_size > (int)sizeof pidbuf)
		fail = "find small";
	else if (do_lstat(pid_file, &st2) < 0)
		fail = "lstat";
	else if (!S_ISREG(st1.st_mode))
		fail = "avoid file overwrite race for";
	else if (st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino)
		fail = "verify stat info for";
#ifdef HAVE_FTRUNCATE
	else if (do_ftruncate(pid_file_fd, 0) < 0)
		fail = "truncate";
#endif
	else {
		pid_t pid = getpid();
		int len = snprintf(pidbuf, sizeof pidbuf, "%d\n", (int)pid);
#ifndef HAVE_FTRUNCATE
		/* What can we do with a too-long file and no truncate? I guess we'll add extra newlines. */
		while (len < st1.st_size) /* We already verified that st_size chars fits in the buffer. */
			pidbuf[len++] = '\n';
		/* We don't need the buffer to end in a '\0' (and we may not have room to add it). */
#endif
		if (write(pid_file_fd, pidbuf, len) != len)
			 fail = "write";
		cleanup_set_pid(pid); /* Mark the file for removal on exit, even if the write failed. */
	}

	if (fail) {
		char msg[1024];