libcgroup: Fix segmentation fault in APIs.

Dan Smith reported some segmentation faults. It turns out that we did
not NULL terminate all the structures when we had moved to the wrapper
based approach. With this in mind, the loop checks the index instead
of a NULL structure.

Also remove unwanted NULL terminations.

Thanks to Dan for excellent debugging.

Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>



git-svn-id: https://libcg.svn.sourceforge.net/svnroot/libcg/tags/v0.1c@77 4f4bb910-9a46-0410-90c8-c897d4f1cd53

2 files changed, 13 insertions, 22 deletions

diff --git a/api.c b/api.c
index 6250ceb..0adeeb5 100644
--- a/api.c
+++ b/api.c
@@ -279,13 +279,11 @@ int cgroup_attach_task_pid(struct cgroup *cgroup, pid_t tid)
 			fclose(tasks);
 		}
 	} else {
-		for (i = 0; i <= CG_CONTROLLER_MAX &&
-				cgroup->controller[i] != NULL; i++) {
+		for (i = 0; i < cgroup->index; i++) {
 			if (!cgroup_test_subsys_mounted(cgroup->controller[i]->name))
 				return ECGROUPSUBSYSNOTMOUNTED;
 		}
-		for (i = 0; i <= CG_CONTROLLER_MAX &&
-				cgroup->controller[i] != NULL ; i++) {
+		for (i = 0; i <= cgroup->index; i++) {
 			if (!cg_build_path(cgroup->name, path,
 					cgroup->controller[i]->name))
 				continue;
@@ -412,21 +410,18 @@ int cgroup_modify_cgroup(struct cgroup *cgroup)
 	if (!cgroup_initialized)
 		return ECGROUPNOTINITALIZED;
 
-	for (i = 0; i <= CG_CONTROLLER_MAX && cgroup->controller[i] != NULL;
-									i++) {
+	for (i = 0; i < cgroup->index; i++) {
 		if (!cgroup_test_subsys_mounted(cgroup->controller[i]->name))
 			return ECGROUPSUBSYSNOTMOUNTED;
 	}
 
-	for (i = 0; i < CG_CONTROLLER_MAX && cgroup->controller[i];
-						i++, strcpy(path, base)) {
+	for (i = 0; i < cgroup->index; i++, strcpy(path, base)) {
 		int j;
 		if (!cg_build_path(cgroup->name, base,
 			cgroup->controller[i]->name))
 			continue;
-		for(j = 0; j < CG_NV_MAX &&
-			cgroup->controller[i]->values[j];
-			j++, strcpy(path, base)) {
+		for (j = 0; j < cgroup->controller[i]->index; j++,
+						strcpy(path, base)) {
 			strcat(path, cgroup->controller[i]->values[j]->name);
 			error = cg_set_control_value(path,
 				cgroup->controller[i]->values[j]->value);
@@ -455,8 +450,7 @@ int cgroup_create_cgroup(struct cgroup *cgroup, int ignore_ownership)
 	if (!cgroup_initialized)
 		return ECGROUPNOTINITALIZED;
 
-	for (i = 0; i <= CG_CONTROLLER_MAX && cgroup->controller[i] != NULL;
-									i++) {
+	for (i = 0; i < cgroup->index;	i++) {
 		if (!cgroup_test_subsys_mounted(cgroup->controller[i]->name))
 			return ECGROUPSUBSYSNOTMOUNTED;
 	}
@@ -472,7 +466,7 @@ int cgroup_create_cgroup(struct cgroup *cgroup, int ignore_ownership)
 	 * subsystems mounted at one point, all of them *have* be on the cgroup
 	 * data structure. If not, we fail.
 	 */
-	for (k = 0; k < CG_CONTROLLER_MAX && cgroup->controller[k]; k++) {
+	for (k = 0; k < cgroup->index; k++) {
 		path[0] = '\0';
 
 		if (!cg_build_path(cgroup->name, path,
@@ -493,8 +487,8 @@ int cgroup_create_cgroup(struct cgroup *cgroup, int ignore_ownership)
 		if (error)
 			goto err;
 
-		for (j = 0; j < CG_NV_MAX && cgroup->controller[k]->values[j];
-					j++, strcpy(path, base)) {
+		for (j = 0; j < cgroup->controller[k]->index; j++,
+							strcpy(path, base)) {
 			strcat(path, cgroup->controller[k]->values[j]->name);
 			error = cg_set_control_value(path,
 				cgroup->controller[k]->values[j]->value);
@@ -538,13 +532,12 @@ int cgroup_delete_cgroup(struct cgroup *cgroup, int ignore_migration)
 	if (!cgroup_initialized)
 		return ECGROUPNOTINITALIZED;
 
-	for (i = 0; i <= CG_CONTROLLER_MAX && cgroup->controller[i] != NULL;
-									i++) {
+	for (i = 0; i < cgroup->index; i++) {
 		if (!cgroup_test_subsys_mounted(cgroup->controller[i]->name))
 			return ECGROUPSUBSYSNOTMOUNTED;
 	}
 
-	for (i = 0; i < CG_CONTROLLER_MAX && cgroup->controller; i++) {
+	for (i = 0; i < cgroup->index; i++) {
 		if (!cg_build_path(cgroup->name, path,
 					cgroup->controller[i]->name))
 			continue;
@@ -585,7 +578,7 @@ del_open_err:
 		fclose(base_tasks);
 base_open_err:
 	if (ignore_migration) {
-		for (i = 0; cgroup->controller[i] != NULL; i++) {
+		for (i = 0; i < cgroup->index; i++) {
 			if (!cg_build_path(cgroup->name, path,
 						cgroup->controller[i]->name))
 				continue;
diff --git a/wrapper.c b/wrapper.c
index 916710f..3503194 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -37,7 +37,6 @@ struct cgroup *cgroup_new_cgroup(const char *name, uid_t tasks_uid,
 	cgroup->control_uid = control_uid;
 	cgroup->control_gid = control_gid;
 	cgroup->index = 0;
-	cgroup->controller[cgroup->index] = NULL;
 
 	return cgroup;
 }
@@ -71,7 +70,6 @@ struct cgroup_controller *cgroup_add_controller(struct cgroup *cgroup,
 
 	strncpy(controller->name, name, sizeof(controller->name));
 	controller->index = 0;
-	controller->values[controller->index] = NULL;
 
 	cgroup->controller[cgroup->index] = controller;
 	cgroup->index++;