| 1 | /* |
| 2 | * Copyright (C) 2012 David Goulet <dgoulet@efficios.com> |
| 3 | * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 4 | * |
| 5 | * SPDX-License-Identifier: LGPL-2.1-only |
| 6 | * |
| 7 | */ |
| 8 | |
| 9 | #include <common/error.hpp> |
| 10 | #include <common/lockfile.hpp> |
| 11 | #include <common/macros.hpp> |
| 12 | |
| 13 | #ifdef HAVE_FLOCK |
| 14 | |
| 15 | #else /* HAVE_FLOCK */ |
| 16 | |
| 17 | #include <fcntl.h> |
| 18 | |
| 19 | int utils_create_lock_file(const char *filepath) |
| 20 | { |
| 21 | int ret; |
| 22 | int fd; |
| 23 | struct flock lock; |
| 24 | |
| 25 | LTTNG_ASSERT(filepath); |
| 26 | |
| 27 | memset(&lock, 0, sizeof(lock)); |
| 28 | fd = open(filepath, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP); |
| 29 | if (fd < 0) { |
| 30 | PERROR("open lock file %s", filepath); |
| 31 | fd = -1; |
| 32 | goto error; |
| 33 | } |
| 34 | |
| 35 | /* |
| 36 | * Attempt to lock the file. If this fails, there is |
| 37 | * already a process using the same lock file running |
| 38 | * and we should exit. |
| 39 | */ |
| 40 | lock.l_whence = SEEK_SET; |
| 41 | lock.l_type = F_WRLCK; |
| 42 | |
| 43 | ret = fcntl(fd, F_SETLK, &lock); |
| 44 | if (ret == -1) { |
| 45 | PERROR("fcntl lock file"); |
| 46 | ERR("Could not get lock file %s, another instance is running.", filepath); |
| 47 | if (close(fd)) { |
| 48 | PERROR("close lock file"); |
| 49 | } |
| 50 | fd = ret; |
| 51 | goto error; |
| 52 | } |
| 53 | |
| 54 | error: |
| 55 | return fd; |
| 56 | } |
| 57 | |
| 58 | #endif /* HAVE_FLOCK */ |