diff options
| -rw-r--r-- | liberty.c | 47 |
1 files changed, 47 insertions, 0 deletions
@@ -3051,6 +3051,53 @@ format_host_port_pair (const char *host, const char *port) // --- File system ------------------------------------------------------------- +static int +lock_pid_file (const char *path, struct error **e) +{ + // When using XDG_RUNTIME_DIR, the file needs to either have its + // access time bumped every 6 hours, or have the sticky bit set + int fd = open (path, O_RDWR | O_CREAT, + S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH /* 644 */ | S_ISVTX /* sticky */); + if (fd < 0) + { + error_set (e, "can't open `%s': %s", path, strerror (errno)); + return -1; + } + + set_cloexec (fd); + + struct flock lock = + { + .l_type = F_WRLCK, + .l_start = 0, + .l_whence = SEEK_SET, + .l_len = 0, + }; + if (fcntl (fd, F_SETLK, &lock)) + { + error_set (e, "can't lock `%s': %s", path, strerror (errno)); + xclose (fd); + return -1; + } + + struct str pid; + str_init (&pid); + str_append_printf (&pid, "%ld", (long) getpid ()); + + if (ftruncate (fd, 0) + || write (fd, pid.str, pid.len) != (ssize_t) pid.len) + { + error_set (e, "can't write to `%s': %s", path, strerror (errno)); + xclose (fd); + return -1; + } + str_free (&pid); + + // Intentionally not closing the file descriptor; it must stay alive + // for the entire life of the application + return fd; +} + static bool ensure_directory_existence (const char *path, struct error **e) { |