libmount: small lock code cleanup

Signed-off-by: Karel Zak <kzak@redhat.com>

shlibs/mount/src/lock.c

@@ -41,8 +41,8 @@ struct libmnt_lock {
 	char	*linkfile;	/* path to link file (e.g. /etc/mtab~.<id>) */
 	int	lockfile_fd;	/* lock file descriptor */
 
-	int	locked :1;	/* do we own the lock? */
-	int	sigblock: 1;	/* block signals when locked */
+	int	locked : 1;	/* do we own the lock? */
+	int	sigblock : 1;	/* block signals when locked */
 
 	sigset_t oldsigmask;
 };
@@ -100,7 +100,7 @@ void mnt_free_lock(struct libmnt_lock *ml)
 {
 	if (!ml)
 		return;
-	DBG(LOCKS, mnt_debug_h(ml, "free"));
+	DBG(LOCKS, mnt_debug_h(ml, "free%s", ml->locked ? " !!! LOCKED !!!" : ""));
 	free(ml->lockfile);
 	free(ml->linkfile);
 	free(ml);
@@ -120,7 +120,8 @@ int mnt_lock_block_signals(struct libmnt_lock *ml, int enable)
 {
 	if (!ml)
 		return -EINVAL;
-	ml->sigblock = enable;
+	DBG(LOCKS, mnt_debug_h(ml, "signals: %s", enable ? "BLOCKED" : "UNBLOCKED"));
+	ml->sigblock = enable ? 1 : 0;
 	return 0;
 }
 
@@ -248,8 +249,7 @@ void mnt_unlock_file(struct libmnt_lock *ml)
 	if (!ml)
 		return;
 
-
-	if (ml->locked == 0 && ml->lockfile && ml->linkfile)
+	if (!ml->locked && ml->lockfile && ml->linkfile)
 	{
 		/* We have (probably) all files, but we don't own the lock,
 		 * Really? Check it! Maybe ml->locked wasn't set properly
@@ -271,15 +271,17 @@ void mnt_unlock_file(struct libmnt_lock *ml)
 		unlink(ml->linkfile);
 	if (ml->lockfile_fd >= 0)
 		close(ml->lockfile_fd);
-	if (ml->locked == 1 && ml->lockfile)
+	if (ml->locked && ml->lockfile) {
 		unlink(ml->lockfile);
-
+		DBG(LOCKS, mnt_debug_h(ml, "unlink %s", ml->lockfile));
+	}
 	ml->locked = 0;
 	ml->lockfile_fd = -1;
 
-	if (ml->sigblock)
+	if (ml->sigblock) {
+		DBG(LOCKS, mnt_debug_h(ml, "restoring sigmask"));
 		sigprocmask(SIG_SETMASK, &ml->oldsigmask, NULL);
-
+	}
 	ml->sigblock = 0;
 }
 
@@ -396,7 +398,7 @@ int mnt_lock_file(struct libmnt_lock *ml)
 	waittime.tv_nsec = (1000 * MOUNTLOCK_WAITTIME);
 
 	/* Repeat until it was us who made the link */
-	while (ml->locked == 0) {
+	while (!ml->locked) {
 		struct timeval now;
 		struct flock flock;
 		int j;
@@ -459,9 +461,8 @@ int mnt_lock_file(struct libmnt_lock *ml)
 			ml->lockfile_fd = -1;
 		}
 	}
-	DBG(LOCKS, mnt_debug_h(ml,
-			"%s: (%d) successfully locked\n",
-			lockfile, getpid()));
+	DBG(LOCKS, mnt_debug_h(ml, "%s: (%d) successfully locked",
+					lockfile, getpid()));
 	unlink(linkfile);
 	return 0;
 

shlibs/mount/src/tab_update.c

@@ -83,7 +83,7 @@ void mnt_free_update(struct libmnt_update *upd)
 }
 
 /*
- * Returns 0 on success, 1 if not file available, -1 in case of error.
+ * Returns 0 on success, <0 in case of error.
  */
 int mnt_update_set_filename(struct libmnt_update *upd, const char *filename,
 			    int userspace_only)
@@ -114,7 +114,7 @@ int mnt_update_set_filename(struct libmnt_update *upd, const char *filename,
 		path = NULL;
 		mnt_has_regular_utab(&path, &rw);
 		if (!rw)
-			return 1;
+			return -EACCES;
 		upd->userspace_only = TRUE;
 	}
 	upd->filename = strdup(path);
@@ -157,7 +157,7 @@ int mnt_update_is_ready(struct libmnt_update *upd)
  * @target: umount target, must be num for mount
  * @fs: mount filesystem description, must be NULL for umount
  *
- * Returns: -1 in case on error, 0 on success, 1 if update is unnecessary.
+ * Returns: <0 in case on error, 0 on success, 1 if update is unnecessary.
  */
 int mnt_update_set_fs(struct libmnt_update *upd, unsigned long mountflags,
 		      const char *target, struct libmnt_fs *fs)
@@ -195,9 +195,10 @@ int mnt_update_set_fs(struct libmnt_update *upd, unsigned long mountflags,
 	upd->mountflags = mountflags;
 
 	rc = mnt_update_set_filename(upd, NULL, 0);
-	if (rc)
+	if (rc) {
+		DBG(UPDATE, mnt_debug_h(upd, "no writable file available [rc=%d]", rc));
 		return rc;	/* error or no file available (rc = 1) */
-
+	}
 	if (target) {
 		upd->target = strdup(target);
 		if (!upd->target)
@@ -693,12 +694,13 @@ static int update_remove_entry(struct libmnt_update *upd, struct libmnt_lock *lc
 			rc = update_table(upd, tb);
 			mnt_free_fs(rem);
 		}
-		mnt_free_table(tb);
 	}
 	if (lc)
 		mnt_unlock_file(lc);
 	else if (u_lc != -1)
 		utab_unlock(u_lc);
+
+	mnt_free_table(tb);
 	return rc;
 }
 
@@ -724,12 +726,13 @@ static int update_modify_target(struct libmnt_update *upd, struct libmnt_lock *l
 			if (!rc)
 				rc = update_table(upd, tb);
 		}
-		mnt_free_table(tb);
 	}
 	if (lc)
 		mnt_unlock_file(lc);
 	else if (u_lc != -1)
 		utab_unlock(u_lc);
+
+	mnt_free_table(tb);
 	return rc;
 }
 
@@ -765,13 +768,14 @@ static int update_modify_options(struct libmnt_update *upd, struct libmnt_lock *
 			if (!rc)
 				rc = update_table(upd, tb);
 		}
-		mnt_free_table(tb);
 	}
 
 	if (lc)
 		mnt_unlock_file(lc);
 	else if (u_lc != -1)
 		utab_unlock(u_lc);
+
+	mnt_free_table(tb);
 	return rc;
 }
 
@@ -805,7 +809,6 @@ int mnt_update_table(struct libmnt_update *upd, struct libmnt_lock *lc)
 	if (upd->fs) {
 		DBG(UPDATE, mnt_fs_print_debug(upd->fs, stderr));
 	}
-
 	if (!lc && !upd->userspace_only) {
 		lc = mnt_new_lock(upd->filename, 0);
 		if (lc)

shlibs/mount/src/utils.c

@@ -602,8 +602,8 @@ done:
  * If the file does not exist and @writable argument is not NULL then it will
  * try to create the directory (e.g. /dev/.mount) and the file.
  *
- * Returns: 1 if /etc/utab is a reqular file, and 0 in case of error (check
- *          errno for more details).
+ * Returns: 1 if /dev/.mount/utab is a reqular file, and 0 in case of
+ *          error (check errno for more details).
  */
 
 int mnt_has_regular_utab(const char **utab, int *writable)