NULL dereference fixes in code base after running with 'clang'

* 212 logical (NULL deref/divide by zero) errors reduced to 28
  (27 of them in contrib/ and lex part of codebase, 1 is invalid)
* 11 API errors reduced to 0

Signed-off-by: Amar Tumballi <amar@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 966 (NULL check for avoiding NULL dereferencing of pointers..)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=966

7 files changed, 44 insertions, 29 deletions

diff --git a/xlators/cluster/afr/src/afr-inode-read.c b/xlators/cluster/afr/src/afr-inode-read.c
index b1bbac10b..ef72fb197 100644
--- a/xlators/cluster/afr/src/afr-inode-read.c
+++ b/xlators/cluster/afr/src/afr-inode-read.c
@@ -802,7 +802,7 @@ afr_readv_cbk (call_frame_t *frame, void *cookie,
 
 out:
 	if (unwind) {
-                if (buf)
+                if (buf && local)
                         buf->ia_ino = local->cont.readv.ino;
 
 		AFR_STACK_UNWIND (readv, frame, op_ret, op_errno,
diff --git a/xlators/cluster/afr/src/afr.c b/xlators/cluster/afr/src/afr.c
index 718384717..4ae128bbb 100644
--- a/xlators/cluster/afr/src/afr.c
+++ b/xlators/cluster/afr/src/afr.c
@@ -2744,7 +2744,7 @@ init (xlator_t *this)
 
         int32_t background_count  = 0;
 	int32_t lock_server_count = 1;
-        int32_t window_size;
+        int32_t window_size       = 0;
 
 	int    fav_ret       = -1;
 	int    read_ret      = -1;
@@ -2780,8 +2780,8 @@ init (xlator_t *this)
 				   &background_count);
 	if (dict_ret == 0) {
 		gf_log (this->name, GF_LOG_DEBUG,
-			"Setting background self-heal count to %d.",
-			window_size);
+			"Setting background self-heal count to %d",
+			background_count);
 
 		priv->background_self_heal_count = background_count;
 	}
@@ -2819,7 +2819,7 @@ init (xlator_t *this)
 				   &window_size);
 	if (dict_ret == 0) {
 		gf_log (this->name, GF_LOG_DEBUG,
-			"Setting data self-heal window size to %d.",
+			"Setting data self-heal window size to %d",
 			window_size);
 
 		priv->data_self_heal_window_size = window_size;
diff --git a/xlators/cluster/afr/src/afr.h b/xlators/cluster/afr/src/afr.h
index b223a9de3..4580bcda2 100644
--- a/xlators/cluster/afr/src/afr.h
+++ b/xlators/cluster/afr/src/afr.h
@@ -558,15 +558,15 @@ typedef struct {
 
 
 /* try alloc and if it fails, goto label */
-#define ALLOC_OR_GOTO(var, type, label) do {			\
-		var = GF_CALLOC (sizeof (type), 1,              \
-                                gf_afr_mt_##type);               \
-		if (!var) {					\
-			gf_log (this->name, GF_LOG_ERROR,	\
-				"out of memory :(");		\
-			op_errno = ENOMEM;			\
-			goto label;				\
-		}						\
+#define ALLOC_OR_GOTO(var, type, label) do {                     \
+		var = GF_CALLOC (sizeof (type), 1,               \
+                                 gf_afr_mt_##type);              \
+		if (!var) {                                      \
+			gf_log (this->name, GF_LOG_ERROR,        \
+				"out of memory :(");             \
+			op_errno = ENOMEM;                       \
+			goto label;                              \
+		}                                                \
 	} while (0);
 
 
@@ -639,13 +639,15 @@ afr_cleanup_fd_ctx (xlator_t *this, fd_t *fd);
 	do {						\
 		afr_local_t *__local = NULL;		\
 		xlator_t    *__this = NULL;		\
-		__local = frame->local;			\
-		__this = frame->this;			\
-		frame->local = NULL;                    \
+                if (frame) {                            \
+                        __local = frame->local;		\
+                        __this = frame->this;           \
+                        frame->local = NULL;            \
+                }                                               \
 		STACK_UNWIND_STRICT (fop, frame, params);       \
-		afr_local_cleanup (__local, __this);	\
+		afr_local_cleanup (__local, __this);            \
 		GF_FREE (__local);				\
-} while (0);					
+        } while (0);
 
 #define AFR_STACK_DESTROY(frame)			\
 	do {						\
@@ -657,7 +659,7 @@ afr_cleanup_fd_ctx (xlator_t *this, fd_t *fd);
 		STACK_DESTROY (frame->root);		\
 		afr_local_cleanup (__local, __this);	\
 		GF_FREE (__local);			\
-} while (0);					
+        } while (0);
 
 /* allocate and return a string that is the basename of argument */
 static inline char * 
diff --git a/xlators/cluster/dht/src/dht-common.h b/xlators/cluster/dht/src/dht-common.h
index b51f308ec..b361f1442 100644
--- a/xlators/cluster/dht/src/dht-common.h
+++ b/xlators/cluster/dht/src/dht-common.h
@@ -183,9 +183,11 @@ typedef struct dht_disk_layout dht_disk_layout_t;
 #define DHT_STACK_UNWIND(fop, frame, params ...) do {           \
 		dht_local_t *__local = NULL;                    \
                 xlator_t *__xl = NULL;                          \
-                __xl = frame->this;                             \
-		__local = frame->local;                         \
-		frame->local = NULL;                            \
+                if (frame) {                                    \
+                        __xl = frame->this;                     \
+                        __local = frame->local;                 \
+                        frame->local = NULL;                    \
+                }                                               \
 		STACK_UNWIND_STRICT (fop, frame, params);       \
 		dht_local_wipe (__xl, __local);                 \
 	} while (0)
diff --git a/xlators/cluster/dht/src/dht-rename.c b/xlators/cluster/dht/src/dht-rename.c
index d96c4b8a3..d88fc7445 100644
--- a/xlators/cluster/dht/src/dht-rename.c
+++ b/xlators/cluster/dht/src/dht-rename.c
@@ -260,6 +260,12 @@ dht_rename_unlink_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
 	local = frame->local;
 	prev  = cookie;
 
+        if (!local) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "!local, should not happen");
+                goto out;
+        }
+
 	this_call_cnt = dht_frame_return (frame);
 
 	if (op_ret == -1) {
@@ -273,12 +279,14 @@ dht_rename_unlink_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
         WIPE (&local->preparent);
         WIPE (&local->postparent);
 
-	if (is_last_call (this_call_cnt))
+	if (is_last_call (this_call_cnt)) {
 		DHT_STACK_UNWIND (rename, frame, local->op_ret, local->op_errno,
 				  &local->stbuf, &local->preoldparent,
                                   &local->postoldparent, &local->preparent,
                                   &local->postparent);
+        }
 
+out:
 	return 0;
 }
 
diff --git a/xlators/cluster/dht/src/dht-selfheal.c b/xlators/cluster/dht/src/dht-selfheal.c
index 8cfb1f41f..9270952e1 100644
--- a/xlators/cluster/dht/src/dht-selfheal.c
+++ b/xlators/cluster/dht/src/dht-selfheal.c
@@ -336,7 +336,7 @@ dht_selfheal_layout_new_directory (call_frame_t *frame, loc_t *loc,
                 }
         }
 
-	chunk = ((unsigned long) 0xffffffff) / cnt;
+	chunk = ((unsigned long) 0xffffffff) / ((cnt) ? cnt : 1);
 
 	start_subvol = dht_selfheal_layout_alloc_start (this, loc, layout);
 
diff --git a/xlators/cluster/stripe/src/stripe.c b/xlators/cluster/stripe/src/stripe.c
index 99346fac2..4826d80a8 100644
--- a/xlators/cluster/stripe/src/stripe.c
+++ b/xlators/cluster/stripe/src/stripe.c
@@ -3284,7 +3284,6 @@ stripe_readv (call_frame_t *frame, xlator_t *this, fd_t *fd,
         call_frame_t     *rframe = NULL;
         stripe_local_t   *rlocal = NULL;
         xlator_list_t    *trav = NULL;
-        stripe_private_t *priv = NULL;
         stripe_fd_ctx_t  *fctx = NULL;
 
         VALIDATE_OR_GOTO (frame, err);
@@ -3293,7 +3292,6 @@ stripe_readv (call_frame_t *frame, xlator_t *this, fd_t *fd,
         VALIDATE_OR_GOTO (fd->inode, err);
 
         trav = this->children;
-        priv = this->private;
 
         fd_ctx_get (fd, this, &tmp_fctx);
         if (!tmp_fctx) {
@@ -3303,6 +3301,11 @@ stripe_readv (call_frame_t *frame, xlator_t *this, fd_t *fd,
         fctx = (stripe_fd_ctx_t *)(long)tmp_fctx;
         stripe_size = fctx->stripe_size;
 
+        if (!stripe_size) {
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "Wrong stripe size for the file");
+                goto err;
+        }
         /* The file is stripe across the child nodes. Send the read request
          * to the child nodes appropriately after checking which region of
          * the file is in which child node. Always '0-<stripe_size>' part of
@@ -3310,7 +3313,7 @@ stripe_readv (call_frame_t *frame, xlator_t *this, fd_t *fd,
          */
         rounded_start = floor (offset, stripe_size);
         rounded_end = roof (offset+size, stripe_size);
-        num_stripe = rounded_end/stripe_size - rounded_start/stripe_size;
+        num_stripe = (rounded_end- rounded_start)/stripe_size;
 
         local = GF_CALLOC (1, sizeof (stripe_local_t),
                            gf_stripe_mt_stripe_local_t);
@@ -3361,7 +3364,7 @@ stripe_readv (call_frame_t *frame, xlator_t *this, fd_t *fd,
 
         return 0;
 err:
-        if (local->fd)
+        if (local && local->fd)
                 fd_unref (local->fd);
 
         STACK_UNWIND_STRICT (readv, frame, -1, op_errno, NULL, 0, NULL, NULL);