Ensure all filesystems listed in /proc/mounts are unmounted

The iterator function getmntent() is not stable. It may skip
entries if the contents of the iterated file changes, which
is the case with /proc/mounts when filesystems are unmounted.
As a result, some filesystems were never unmounted.

To fix this, iteratation is now restarted after every
sucessful unmount.

Signed-off-by: Robert Andersson <robert.m.andersson@atlascopco.com>
Signed-off-by: Ming Liu <liu.ming50@gmail.com>

src/mount.c

@@ -59,46 +59,54 @@ static int is_protected(char *dir)
 	return 0;
 }
 
-static struct mntent *iterator(char *fstab)
+static void iterator_end(FILE **fp)
+{
+	endmntent(*fp);
+	*fp = NULL;
+}
+
+static struct mntent *iterator(char *fstab, FILE **fp)
 {
-	static FILE *fp = NULL;
 	static struct mntent *mnt;
 
-	if (!fp && fstab) {
+	if (!*fp && fstab) {
-		fp = setmntent(fstab, "r");
+		*fp = setmntent(fstab, "r");
-		if (!fp)
+		if (!*fp)
 			return NULL;
 	}
 
-	while ((mnt = getmntent(fp))) {
+	while ((mnt = getmntent(*fp))) {
 		if (is_protected(mnt->mnt_dir))
 			continue;
 
 		return mnt;
 	}
 
-	endmntent(fp);
+	iterator_end(fp);
-	fp = NULL;
-
 	return NULL;
 }
 
 void unmount_tmpfs(void)
 {
 	struct mntent *mnt;
+	FILE *fp = NULL;
 
-	while ((mnt = iterator("/proc/mounts"))) {
+	while ((mnt = iterator("/proc/mounts", &fp))) {
-		if (!strcmp("tmpfs", mnt->mnt_fsname))
+		if (!strcmp("tmpfs", mnt->mnt_fsname) && !umount(mnt->mnt_dir))
-			umount(mnt->mnt_dir);
+			iterator_end(&fp);  // Restart iteration
 	}
 }
 
 void unmount_regular(void)
 {
 	struct mntent *mnt;
+	FILE *fp = NULL;
 
-	while ((mnt = iterator("/proc/mounts"))) {
+	while ((mnt = iterator("/proc/mounts", &fp))) {
-		umount(mnt->mnt_dir);
+		if (!umount(mnt->mnt_dir)) {
+			print(0, "Unmounted %s", mnt->mnt_dir);
+			iterator_end(&fp);  // Restart iteration
+		}
 	}
 }