libcgroup: Intialize all pointers in api.c

Recently, while debugging an issue with test cases, I realized the
pitfalls of not initializing your pointers. On looking into api.c,
I realized that a lot of pointers are not initialized. Hence, this
patch.

Tested against the libcgrouptest suite. No regressions could be
were observed.

Balbir says,

> We should avoid double initialization specially if a
>
> *ptr = NULL is followed by
> ptr = malloc(...)
>
> I don't see any concerns right now, but something to be aware of

Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
git-svn-id: https://libcg.svn.sourceforge.net/svnroot/libcg/trunk@298 4f4bb910-9a46-0410-90c8-c897d4f1cd53

diff --git a/api.c b/api.c
index 8867b442de53bbafb5094283f55e79ef04f3b788..b5b8d38380c7bd34e64cfd302f15df0de30f96f7 100644 (file)
--- a/api.c
+++ b/api.c
@@ -532,20 +532,21 @@ finish:
  */
 int cgroup_init()
 {
-       FILE *proc_mount;
-       struct mntent *ent, *temp_ent;
+       FILE *proc_mount = NULL;
+       struct mntent *ent = NULL;
+       struct mntent *temp_ent = NULL;
        int found_mnt = 0;
        int ret = 0;
        static char *controllers[CG_CONTROLLER_MAX];
-       FILE *proc_cgroup;
+       FILE *proc_cgroup = NULL;
        char subsys_name[FILENAME_MAX];
        int hierarchy, num_cgroups, enabled;
        int i=0;
-       char *mntopt;
+       char *mntopt = NULL;
        int err;
-       char *buf;
+       char *buf = NULL;
        char mntent_buffer[4 * FILENAME_MAX];
-       char *strtok_buffer;
+       char *strtok_buffer = NULL;
 
        pthread_rwlock_wrlock(&cg_mount_table_lock);
 
@@ -642,8 +643,9 @@ unlock_exit:
 
 static int cg_test_mounted_fs()
 {
-       FILE *proc_mount;
-       struct mntent *ent, *temp_ent;
+       FILE *proc_mount = NULL;
+       struct mntent *ent = NULL;
+       struct mntent *temp_ent = NULL;
        char mntent_buff[4 * FILENAME_MAX];
        int ret = 1;
 
@@ -722,7 +724,7 @@ char *cg_build_path(char *name, char *path, char *type)
 int cgroup_attach_task_pid(struct cgroup *cgroup, pid_t tid)
 {
        char path[FILENAME_MAX];
-       FILE *tasks;
+       FILE *tasks = NULL;
        int i, ret = 0;
 
        if (!cgroup_initialized) {
@@ -840,11 +842,14 @@ int cgroup_attach_task(struct cgroup *cgroup)
  */
 static int cg_mkdir_p(const char *path)
 {
-       char *real_path, *wd;
+       char *real_path = NULL;
+       char *wd = NULL;
        int i = 0, j = 0;
-       char pos, *str;
+       char pos;
+       char *str = NULL;
        int ret = 0;
-       char cwd[FILENAME_MAX], *buf;
+       char cwd[FILENAME_MAX];
+       char *buf = NULL;
 
        buf = getcwd(cwd, FILENAME_MAX);
        if (!buf)
@@ -927,7 +932,7 @@ static int cg_create_control_group(char *path)
  */
 static int cg_set_control_value(char *path, char *val)
 {
-       FILE *control_file;
+       FILE *control_file = NULL;
        if (!cg_test_mounted_fs())
                return ECGROUPNOTMOUNTED;
 
@@ -1099,7 +1104,8 @@ err:
  */
 int cgroup_create_cgroup(struct cgroup *cgroup, int ignore_ownership)
 {
-       char *fts_path[2], base[FILENAME_MAX], *path;
+       char *fts_path[2], base[FILENAME_MAX];
+       char *path = NULL;
        int i, j, k;
        int error = 0;
        int retval = 0;
@@ -1191,10 +1197,11 @@ err:
  */
 char *cgroup_find_parent(char *name)
 {
-       char child[FILENAME_MAX], *parent;
+       char child[FILENAME_MAX];
+       char *parent = NULL;
        struct stat stat_child, stat_parent;
-       char *type;
-       char *dir;
+       char *type = NULL;
+       char *dir = NULL;
 
        pthread_rwlock_rdlock(&cg_mount_table_lock);
        type = cg_mount_table[0].name;
@@ -1251,8 +1258,8 @@ free_parent:
 int cgroup_create_cgroup_from_parent(struct cgroup *cgroup,
                                        int ignore_ownership)
 {
-       char *parent;
-       struct cgroup *parent_cgroup;
+       char *parent = NULL;
+       struct cgroup *parent_cgroup = NULL;
        int ret = ECGFAIL;
 
        if (!cgroup_initialized)
@@ -1293,7 +1300,7 @@ err_nomem:
  */
 int cgroup_delete_cgroup(struct cgroup *cgroup, int ignore_migration)
 {
-       FILE *delete_tasks, *base_tasks = NULL;
+       FILE *delete_tasks = NULL, *base_tasks = NULL;
        int tids;
        char path[FILENAME_MAX];
        int error = ECGROUPNOTALLOWED;
@@ -1374,7 +1381,7 @@ open_err:
 static int cg_rd_ctrl_file(char *subsys, char *cgroup, char *file, char **value)
 {
        char path[FILENAME_MAX];
-       FILE *ctrl_file;
+       FILE *ctrl_file = NULL;
        int ret;
 
        if (!cg_build_path_locked(cgroup, path, subsys))
@@ -1410,12 +1417,12 @@ static int cg_rd_ctrl_file(char *subsys, char *cgroup, char *file, char **value)
 static int cgroup_fill_cgc(struct dirent *ctrl_dir, struct cgroup *cgroup,
                        struct cgroup_controller *cgc, int index)
 {
-       char *ctrl_name;
-       char *ctrl_file;
+       char *ctrl_name = NULL;
+       char *ctrl_file = NULL;
        char *ctrl_value = NULL;
-       char *d_name;
+       char *d_name = NULL;
        char path[FILENAME_MAX+1];
-       char *buffer;
+       char *buffer = NULL;
        int error = 0;
        struct stat stat_buffer;
 
@@ -1488,9 +1495,9 @@ int cgroup_get_cgroup(struct cgroup *cgroup)
 {
        int i;
        char path[FILENAME_MAX];
-       DIR *dir;
-       struct dirent *ctrl_dir;
-       char *control_path;
+       DIR *dir = NULL;
+       struct dirent *ctrl_dir = NULL;
+       char *control_path = NULL;
        int error;
 
        if (!cgroup_initialized) {
@@ -1619,8 +1626,8 @@ static int cg_prepare_cgroup(struct cgroup *cgroup, pid_t pid,
                                        char *controllers[])
 {
        int ret = 0, i;
-       char *controller;
-       struct cgroup_controller *cptr;
+       char *controller = NULL;
+       struct cgroup_controller *cptr = NULL;
 
        /* Fill in cgroup details.  */
        dbg("Will move pid %d to cgroup '%s'\n", pid, dest);
@@ -1676,7 +1683,8 @@ static int cg_prepare_cgroup(struct cgroup *cgroup, pid_t pid,
 static int cg_prepare_controller_array(char *cstr, char *controllers[])
 {
        int j = 0;
-       char *temp, *saveptr = NULL;
+       char *temp = NULL;
+       char *saveptr = NULL;
 
        do {
                if (j == 0)
@@ -1934,7 +1942,7 @@ int cgroup_change_cgroup_path(char *dest, pid_t pid, char *controllers[])
 void cgroup_print_rules_config(FILE *fp)
 {
        /* Iterator */
-       struct cgroup_rule *itr;
+       struct cgroup_rule *itr = NULL;
 
        /* Loop variable */
        int i = 0;
@@ -2036,9 +2044,9 @@ int cgroup_init_rules_cache()
 int cgroup_get_current_controller_path(pid_t pid, const char *controller,
                                        char **current_path)
 {
-       char *path;
+       char *path = NULL;
        int ret;
-       FILE *pid_cgroup_fd;
+       FILE *pid_cgroup_fd = NULL;
 
        if (!controller)
                return ECGOTHER;