From: Karel Zak <kzak@redhat.com>
Date: Thu, 20 Feb 2014 15:59:11 +0000 (+0100)
Subject: libmount: FS id and parent ID could be zero
X-Git-Tag: v2.24.2~77
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=03f9e8d49debddde24e4900ed948b8db5002d92e;p=thirdparty%2Futil-linux.git

libmount: FS id and parent ID could be zero

It seems that linux 3.14 is able to produce things like:

  19 0 8:3 / / rw,relatime - ext4 /dev/sda3 rw,data=ordered
     ^

Reported-by: Mantas Mikulėnas <grawity@gmail.com>
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/libmount/src/tab.c b/libmount/src/tab.c
index 80b225e3fe..b023504adf 100644
--- a/libmount/src/tab.c
+++ b/libmount/src/tab.c
@@ -47,6 +47,8 @@
 #include "strutils.h"
 #include "loopdev.h"
 
+static int is_mountinfo(struct libmnt_table *tb);
+
 /**
  * mnt_new_table:
  *
@@ -491,7 +493,7 @@ int mnt_table_get_root_fs(struct libmnt_table *tb, struct libmnt_fs **root)
 	assert(tb);
 	assert(root);
 
-	if (!tb || !root)
+	if (!tb || !root || !is_mountinfo(tb))
 		return -EINVAL;
 
 	DBG(TAB, mnt_debug_h(tb, "lookup root fs"));
@@ -501,8 +503,6 @@ int mnt_table_get_root_fs(struct libmnt_table *tb, struct libmnt_fs **root)
 	mnt_reset_iter(&itr, MNT_ITER_FORWARD);
 	while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
 		int id = mnt_fs_get_parent_id(fs);
-		if (!id)
-			break;		/* @tab is not a mountinfo file? */
 
 		if (!*root || id < root_id) {
 			*root = fs;
@@ -510,7 +510,7 @@ int mnt_table_get_root_fs(struct libmnt_table *tb, struct libmnt_fs **root)
 		}
 	}
 
-	return root_id ? 0 : -EINVAL;
+	return *root ? 0 : -EINVAL;
 }
 
 /**
@@ -531,15 +531,13 @@ int mnt_table_next_child_fs(struct libmnt_table *tb, struct libmnt_iter *itr,
 	struct libmnt_fs *fs;
 	int parent_id, lastchld_id = 0, chld_id = 0;
 
-	if (!tb || !itr || !parent)
+	if (!tb || !itr || !parent || !is_mountinfo(tb))
 		return -EINVAL;
 
 	DBG(TAB, mnt_debug_h(tb, "lookup next child of '%s'",
 				mnt_fs_get_target(parent)));
 
 	parent_id = mnt_fs_get_id(parent);
-	if (!parent_id)
-		return -EINVAL;
 
 	/* get ID of the previously returned child */
 	if (itr->head && itr->p != itr->head) {
@@ -570,7 +568,7 @@ int mnt_table_next_child_fs(struct libmnt_table *tb, struct libmnt_iter *itr,
 		}
 	}
 
-	if (!chld_id)
+	if (!*chld)
 		return 1;	/* end of iterator */
 
 	/* set the iterator to the @chld for the next call */
diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c
index 91cc9350e0..f269246fcb 100644
--- a/misc-utils/findmnt.c
+++ b/misc-utils/findmnt.c
@@ -821,8 +821,9 @@ static int tab_is_tree(struct libmnt_table *tb)
 	if (!itr)
 		return 0;
 
-	if (mnt_table_next_fs(tb, itr, &fs) == 0)
-		rc = mnt_fs_get_id(fs) > 0 && mnt_fs_get_parent_id(fs) > 0;
+	rc = (mnt_table_next_fs(tb, itr, &fs) == 0 &&
+	      mnt_fs_is_kernel(fs) &&
+	      mnt_fs_get_root(fs));
 
 	mnt_free_iter(itr);
 	return rc;