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/*
* Copyright (c) 2019-2021 The strace developers.
* All rights reserved.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "tests.h"
#include "xmalloc.h"
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/file.h>
/* Obtain an exclusive lock on dirname(path_name)/lock_name file. */
int
lock_file_by_dirname(const char *path_name, const char *lock_name)
{
const char *slash = path_name ? strrchr(path_name, '/') : NULL;
const int plen = slash ? (int) (slash - path_name) + 1 : 0;
char *lock_file = xasprintf("%.*s%s", plen, path_name, lock_name);
int lock_fd = open(lock_file, O_RDONLY);
if (lock_fd < 0)
perror_msg_and_fail("open: %s", lock_file);
if (flock(lock_fd, LOCK_EX))
perror_msg_and_fail("flock: %s", lock_file);
free(lock_file);
return lock_fd;
}
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