mkfs.btrfs: fix symlink names writing

Found by valgrind:
==8968== Use of uninitialised value of size 8
==8968==    at 0x41CE7D: crc32c_le (crc32c.c:98)
==8968==    by 0x40A1D0: csum_tree_block_size (disk-io.c:82)
==8968==    by 0x40A2D4: csum_tree_block (disk-io.c:105)
==8968==    by 0x40A7D6: write_tree_block (disk-io.c:241)
==8968==    by 0x40ACEE: __commit_transaction (disk-io.c:354)
==8968==    by 0x40AE9E: btrfs_commit_transaction (disk-io.c:385)
==8968==    by 0x42CF66: make_image (mkfs.c:1061)
==8968==    by 0x42DE63: main (mkfs.c:1410)
==8968==  Uninitialised value was created by a stack allocation
==8968==    at 0x42B5FB: add_inode_items (mkfs.c:493)

readlink(2) does not write '\0' for us, so make it manually.

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>

diff --git a/mkfs.c b/mkfs.c
index efd85d5..5e483dc 100644 (file)
--- a/mkfs.c
+++ b/mkfs.c
@@ -709,11 +709,13 @@ static int add_symbolic_link(struct btrfs_trans_handle *trans,
                fprintf(stderr, "readlink failed for %s\n", path_name);
                goto fail;
        }
-       if (ret > sectorsize) {
+       if (ret >= sectorsize) {
                fprintf(stderr, "symlink too long for %s", path_name);
                ret = -1;
                goto fail;
        }
+
+       buf[ret] = '\0'; /* readlink does not do it for us */
        ret = btrfs_insert_inline_extent(trans, root, objectid, 0,
                                         buf, ret + 1);
 fail: