+#define max_buf_len 128
+#define lock_path "/var/lock/LCK.."
+
+/* Lock the device. Return allocated string with a lock name */
+char *lock_device(const char* port)
+{
+ char *lock_file = NULL;
+ char buffer[max_buf_len];
+ const char *aux = rindex(port, '/');
+ int fd, len = strlen(aux) + strlen(lock_path);
+
+ /* Remove leading '/' */
+ if (aux) aux++;
+ else aux = port;
+
+ memset(buffer, 0, sizeof(buffer));
+ lock_file = calloc(len + 1, 1);
+ if (!lock_file) {
+ fprintf(stderr, _("Out of memory error while locking device\n"));
+ return NULL;
+ }
+ /* I think we don't need to use strncpy, as we should have enough
+ * buffer due to strlen results
+ */
+ strcpy(lock_file, lock_path);
+ strcat(lock_file, aux);
+
+ /* Check for the stale lockfile.
+ * The code taken from minicom by Miquel van Smoorenburg */
+ if ((fd = open(lock_file, O_RDONLY)) >= 0) {
+ char buf[max_buf_len];
+ int pid, n = 0;
+
+ n = read(fd, buf, sizeof(buf) - 1);
+ close(fd);
+ if (n > 0) {
+ pid = -1;
+ if (n == 4)
+ /* Kermit-style lockfile. */
+ pid = *(int *)buf;
+ else {
+ /* Ascii lockfile. */
+ buf[n] = 0;
+ sscanf(buf, "%d", &pid);
+ }
+ if (pid > 0 && kill((pid_t)pid, 0) < 0 && errno == ESRCH) {
+ fprintf(stderr, _("Lockfile %s is stale. Overriding it..\n"), lock_file);
+ sleep(1);
+ if (unlink(lock_file) == -1) {
+ fprintf(stderr, _("Overriding failed, please check the permissions\n"));
+ fprintf(stderr, _("Cannot lock device\n"));
+ goto failed;
+ }
+ } else {
+ fprintf(stderr, _("Device already locked.\n"));
+ goto failed;
+ }
+ }
+ /* this must not happen. because we could open the file */
+ /* no wrong permissions are set. only reason could be */
+ /* flock/lockf or a empty lockfile due to a broken binary */
+ /* which is more likely (like gnokii 0.4.0pre11 ;-) */
+ if (n == 0) {
+ fprintf(stderr, _("Unable to read lockfile %s.\n"), lock_file);
+ fprintf(stderr, _("Please check for reason and remove the lockfile by hand.\n"));
+ fprintf(stderr, _("Cannot lock device\n"));
+ goto failed;
+ }
+ }
+
+ /* Try to create a new file, with 0644 mode */
+ fd = open(lock_file, O_CREAT | O_EXCL | O_WRONLY, 0644);
+ if (fd == -1) {
+ if (errno == EEXIST)
+ fprintf(stderr, _("Device seems to be locked by unknown process\n"));
+ else if (errno == EACCES)
+ fprintf(stderr, _("Please check permission on lock directory\n"));
+ else if (errno == ENOENT)
+ fprintf(stderr, _("Cannot create lockfile %s. Please check for existence of path"), lock_file);
+ goto failed;
+ }
+ sprintf(buffer, "%10ld gnokii\n", (long)getpid());
+ write(fd, buffer, strlen(buffer));
+ close(fd);
+ return lock_file;
+failed:
+ free(lock_file);
+ return NULL;
+}
+
+/* Removes lock and frees memory */
+bool unlock_device(char *lock_file)
+{
+ int err;
+
+ if (!lock_file) {
+// fprintf(stderr, _("Cannot unlock device\n"));
+ return false;
+ }
+ err = unlink(lock_file);
+ free(lock_file);
+ return (err + 1);
+}
+