gfs2-utils: master - libgfs2: metafs_path improvements

[Andrew Price]

Gitweb:        http://git.fedorahosted.org/git/?p=gfs2-utils.git;a=commitdiff;h=89f0f242424...
Commit:        89f0f242424a4cc23cd73f0288d17b52d04a900d
Parent:        ec2b6270b291a671b70a17a12389d8fecaabd61b
Author:        Andrew Price 
AuthorDate:    Tue Oct 7 23:23:21 2014 +0100
Committer:     Andrew Price 
CommitterDate: Tue Oct 7 23:23:21 2014 +0100

libgfs2: metafs_path improvements

Switch the metafs_path field in struct gfs2_sbd to be a pointer instead
of a char[PATH_MAX] and use strdup to set it in mount_gfs2_meta. Also
rework the metafs mounting and cleanup code to back out more robustly on
errors and set/reset signal handlers through a single function.

Note the SIGSEGV handler has been removed: when a SIGSEGV handler
returns, execution restarts at the bad instruction which triggered it,
so handling it could only ever cause an infinite loop.

Signed-off-by: Andrew Price 
---
 gfs2/libgfs2/libgfs2.h |    2 +-
 gfs2/libgfs2/misc.c    |   66 +++++++++++++++++++++++++++++-------------------
 2 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/gfs2/libgfs2/libgfs2.h b/gfs2/libgfs2/libgfs2.h
index 6509e9b..60c1989 100644
--- a/gfs2/libgfs2/libgfs2.h
+++ b/gfs2/libgfs2/libgfs2.h
@@ -326,7 +326,7 @@ struct gfs2_sbd {
    struct master_dir md;

int metafs_fd;
-	char metafs_path[PATH_MAX]; /* where metafs is mounted */
+	char *metafs_path; /* where metafs is mounted */
    struct special_blocks eattr_blocks;

uint64_t rg_one_length;
diff --git a/gfs2/libgfs2/misc.c b/gfs2/libgfs2/misc.c
index 6feccad..c72af55 100644
--- a/gfs2/libgfs2/misc.c
+++ b/gfs2/libgfs2/misc.c
@@ -210,8 +210,10 @@ static int lock_for_admin(struct gfs2_sbd *sdp)
    	return -1;

error = flock(sdp->metafs_fd, LOCK_EX);
-	if (error)
+	if (error) {
+		close(sdp->metafs_fd);
    	return -1;
+	}
    if (cfg_debug)
    	printf("Got it.\n");
    return 0;
@@ -222,40 +224,57 @@ static void sighandler(int error)
    metafs_interrupted = 1;
 }

-int mount_gfs2_meta(struct gfs2_sbd *sdp, const char *path)
+static void setsigs(void (*handler)(int))
 {
-	int ret;
-	struct sigaction sa = {	.sa_handler = &sighandler };
-
-	memset(sdp->metafs_path, 0, PATH_MAX);
-	snprintf(sdp->metafs_path, PATH_MAX - 1, "/tmp/.gfs2meta.XXXXXX");
-
-	if(!mkdtemp(sdp->metafs_path))
-		return -1;
+	struct sigaction sa = {	.sa_handler = handler };

sigaction(SIGINT, &sa, NULL);
    sigaction(SIGILL, &sa, NULL);
    sigaction(SIGTERM, &sa, NULL);
    sigaction(SIGHUP, &sa, NULL);
    sigaction(SIGABRT, &sa, NULL);
-	sigaction(SIGSEGV, &sa, NULL);
    sigaction(SIGCONT, &sa, NULL);
    sigaction(SIGUSR1, &sa, NULL);
    sigaction(SIGUSR2, &sa, NULL);
-	ret = mount(path, sdp->metafs_path, "gfs2meta", 0, NULL);
-	if (ret) {
-		rmdir(sdp->metafs_path);
+}
+
+int mount_gfs2_meta(struct gfs2_sbd *sdp, const char *path)
+{
+	int ret;
+
+	sdp->metafs_path = strdup("/tmp/.gfs2meta.XXXXXX");
+	if (sdp->metafs_path == NULL)
    	return -1;
-	}
+
+	if(!mkdtemp(sdp->metafs_path))
+		goto err_free;
+
+	setsigs(sighandler);
+
+	ret = mount(path, sdp->metafs_path, "gfs2meta", 0, NULL);
+	if (ret)
+		goto err_rmdir;
+
    if (lock_for_admin(sdp))
-		return -1;
+		goto err_umount;
+
    return 0;
+
+err_umount:
+	if (umount(sdp->metafs_path))
+		fprintf(stderr, "Could not unmount %s: %s\n", sdp->metafs_path, strerror(errno));
+	setsigs(SIG_DFL);
+err_rmdir:
+	rmdir(sdp->metafs_path);
+err_free:
+	free(sdp->metafs_path);
+	sdp->metafs_path = NULL;
+	return -1;
 }

void cleanup_metafs(struct gfs2_sbd *sdp)
 {
    int ret;
-	struct sigaction sa = {	.sa_handler = SIG_DFL };

if (sdp->metafs_fd <= 0)
    	return;
@@ -268,14 +287,9 @@ void cleanup_metafs(struct gfs2_sbd *sdp)
    		sdp->metafs_path, strerror(errno));
    else
    	rmdir(sdp->metafs_path);
-	sigaction(SIGINT, &sa, NULL);
-	sigaction(SIGILL, &sa, NULL);
-	sigaction(SIGTERM, &sa, NULL);
-	sigaction(SIGHUP, &sa, NULL);
-	sigaction(SIGABRT, &sa, NULL);
-	sigaction(SIGSEGV, &sa, NULL);
-	sigaction(SIGCONT, &sa, NULL);
-	sigaction(SIGUSR1, &sa, NULL);
-	sigaction(SIGUSR2, &sa, NULL);
+
+	setsigs(SIG_DFL);
    metafs_interrupted = 0;
+	free(sdp->metafs_path);
+	sdp->metafs_path = NULL;
 }