STABLE2 - libgfs2: randomize creation of temporary directories formetafs mount

["Fabio M. Di Nitto" <fabbione at fedoraproject dot org>]

Gitweb:        http://git.fedorahosted.org/git/cluster.git?p=cluster.git;a=commitdiff;h=1be9adf2881ad22c264f6fda4fff7bb3c13e87f4
Commit:        1be9adf2881ad22c264f6fda4fff7bb3c13e87f4
Parent:        51bfd01ade6b21c0e78354c9ad1eca541e81b6ad
Author:        Fabio M. Di Nitto <fdinitto@redhat.com>
AuthorDate:    Wed Oct 22 11:30:06 2008 +0200
Committer:     Fabio M. Di Nitto <fdinitto@redhat.com>
CommitterDate: Thu Oct 30 10:35:35 2008 +0100

libgfs2: randomize creation of temporary directories for metafs mount

by using a static path to /tmp, the operation can fail in different
ways.

randomize the path a bit by using the invoking pid. This will also allow
multiple simultaneous invokation of mount_gfs2_meta on different
mountpoints.

Similar to 18b24ae55c3e4abdc256a3b6c4f15ae0116a0f14 there is a small
race condition in this implentation.

Implementation:

- Fix return info from find_gfs2_meta to set TRUE when we find a
  mountpoint in gfs2_sbd struct.

- Add metafs_created_mount to gfs2_sbd struct to propagate info if we
  did create the mount point or not.

- Randomize sdp->metafs_path with pid info.

- Remove the metafs_path mount point if we did create it.

Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>
---
 gfs2/libgfs2/libgfs2.h |    1 +
 gfs2/libgfs2/misc.c    |   17 ++++++++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/gfs2/libgfs2/libgfs2.h b/gfs2/libgfs2/libgfs2.h
index 6197b4a..acca5e7 100644
--- a/gfs2/libgfs2/libgfs2.h
+++ b/gfs2/libgfs2/libgfs2.h
@@ -232,6 +232,7 @@ struct gfs2_sbd {
 	unsigned int writes;
 	int metafs_fd;
 	int metafs_mounted; /* If metafs was already mounted */
+	int metafs_created_mount; /* TRUE if we created the mount point got metafs */
 	char metafs_path[PATH_MAX]; /* where metafs is mounted */
 	struct special_blocks bad_blocks;
 	struct special_blocks dup_blocks;
diff --git a/gfs2/libgfs2/misc.c b/gfs2/libgfs2/misc.c
index 4a6665c..7c414b1 100644
--- a/gfs2/libgfs2/misc.c
+++ b/gfs2/libgfs2/misc.c
@@ -125,11 +125,11 @@ find_gfs2_meta(struct gfs2_sbd *sdp)
 			   meta_path, fstype,mfsoptions, &fsdump, 
 			   &fspass) != 6)
 			continue;
-		
+
 		if (strcmp(meta_device, sdp->device_name) == 0 ||
 		    strcmp(meta_device, sdp->path_name) == 0) {
 			fclose(fp);
-			sdp->metafs_mounted = FALSE;
+			sdp->metafs_mounted = TRUE;
 			strcpy(sdp->metafs_path, meta_path);
 			return TRUE;
 		}
@@ -216,15 +216,20 @@ void
 mount_gfs2_meta(struct gfs2_sbd *sdp)
 {
 	int ret;
+
+	memset(sdp->metafs_path, 0, PATH_MAX);
+	snprintf(sdp->metafs_path, PATH_MAX - 1, "/tmp/.gfs2meta.%d", getpid());
+
 	/* mount the meta fs */
-	strcpy(sdp->metafs_path, "/tmp/.gfs2meta");
 	if (!dir_exists(sdp->metafs_path)) {
 		ret = mkdir(sdp->metafs_path, 0700);
 		if (ret)
 			die("Couldn't create %s : %s\n", sdp->metafs_path,
 			    strerror(errno));
-	}
-		
+		sdp->metafs_created_mount = TRUE;
+	} else
+		sdp->metafs_created_mount = FALSE;
+
 	ret = mount(sdp->path_name, sdp->metafs_path, "gfs2meta", 0, NULL);
 	if (ret)
 		die("Couldn't mount %s : %s\n", sdp->metafs_path,
@@ -266,6 +271,8 @@ cleanup_metafs(struct gfs2_sbd *sdp)
 		if (ret)
 			fprintf(stderr, "Couldn't unmount %s : %s\n",
 				sdp->metafs_path, strerror(errno));
+		if(sdp->metafs_created_mount) /* we created the directory */
+			rmdir(sdp->metafs_path);
 	}
 }