clang: Fix various missing checks for empty list

When using list_for_each_entry(_safe) functions, care needs
to be taken that the list passed in are not empty, as these
functions are not empty list safe.

clag scan reported various points where this this pattern
could be caught, and this patch fixes the same.

Additionally the following changes are present in this patch,
- Added an explicit op_ret setting in error case in the
macro MAKE_INODE_HANDLE to address another clang issue reported
- Minor refactoring of some functions in quota code, to address
possible allocation failures in certain functions (which in turn
cause possible empty lists to be passed around)

Change-Id: I1e761a8d218708f714effb56fa643df2a3ea2cc7
Updates: bz#1622665
Signed-off-by: ShyamsundarR <srangana@redhat.com>

1 files changed, 46 insertions, 26 deletions

diff --git a/xlators/features/quota/src/quota.c b/xlators/features/quota/src/quota.c
index 84df5c3caf..418edfc094 100644
--- a/xlators/features/quota/src/quota.c
+++ b/xlators/features/quota/src/quota.c
@@ -674,39 +674,43 @@ quota_timeout(struct timeval *tv, int32_t timeout)
 
 /* Return: 1 if new entry added
  *         0 no entry added
+ *        -1 on errors
  */
 static int32_t
 quota_add_parent(struct list_head *list, char *name, uuid_t pgfid)
 {
     quota_dentry_t *entry = NULL;
     gf_boolean_t found = _gf_false;
+    int ret = 0;
 
-    if (list == NULL) {
-        goto out;
-    }
-
-    list_for_each_entry(entry, list, next)
-    {
-        if (gf_uuid_compare(pgfid, entry->par) == 0) {
-            found = _gf_true;
-            goto out;
+    if (!list_empty(list)) {
+        list_for_each_entry(entry, list, next)
+        {
+            if (gf_uuid_compare(pgfid, entry->par) == 0) {
+                found = _gf_true;
+                goto out;
+            }
         }
     }
 
     entry = __quota_dentry_new(NULL, name, pgfid);
     if (entry)
         list_add_tail(&entry->next, list);
+    else
+        ret = -1;
 
 out:
     if (found)
         return 0;
-    else
+    else if (ret == 0)
         return 1;
+    else
+        return -1;
 }
 
 /* This function iterates the parent list in inode
  * context and add unique parent to the list
- * Returns number of dentry added to the list
+ * Returns number of dentry added to the list, or -1 on errors
  */
 static int32_t
 quota_add_parents_from_ctx(quota_inode_ctx_t *ctx, struct list_head *list)
@@ -723,15 +727,16 @@ quota_add_parents_from_ctx(quota_inode_ctx_t *ctx, struct list_head *list)
         list_for_each_entry(dentry, &ctx->parents, next)
         {
             ret = quota_add_parent(list, dentry->name, dentry->par);
-
             if (ret == 1)
                 count++;
+            else if (ret == -1)
+                break;
         }
     }
     UNLOCK(&ctx->lock);
 
 out:
-    return count;
+    return (ret == -1) ? -1 : count;
 }
 
 int32_t
@@ -750,10 +755,9 @@ quota_build_ancestry_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
     quota_dentry_t *dentry = NULL;
     quota_dentry_t *tmp = NULL;
     quota_inode_ctx_t *ctx = NULL;
-    struct list_head parents = {
-        0,
-    };
+    struct list_head parents;
     quota_local_t *local = NULL;
+    int ret;
 
     INIT_LIST_HEAD(&parents);
 
@@ -828,7 +832,11 @@ quota_build_ancestry_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
 
     quota_inode_ctx_get(local->loc.inode, this, &ctx, 0);
 
-    quota_add_parents_from_ctx(ctx, &parents);
+    ret = quota_add_parents_from_ctx(ctx, &parents);
+    if (ret == -1) {
+        op_errno = errno;
+        goto err;
+    }
 
     if (list_empty(&parents)) {
         /* we built ancestry for a directory */
@@ -843,7 +851,11 @@ quota_build_ancestry_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
            GF_ASSERT (&entry->list != &entries->list);
         */
 
-        quota_add_parent(&parents, entry->d_name, parent->gfid);
+        ret = quota_add_parent(&parents, entry->d_name, parent->gfid);
+        if (ret == -1) {
+            op_errno = errno;
+            goto err;
+        }
     }
 
     local->ancestry_cbk(&parents, local->loc.inode, 0, 0, local->ancestry_data);
@@ -861,9 +873,11 @@ cleanup:
         parent = NULL;
     }
 
-    list_for_each_entry_safe(dentry, tmp, &parents, next)
-    {
-        __quota_dentry_free(dentry);
+    if (!list_empty(&parents)) {
+        list_for_each_entry_safe(dentry, tmp, &parents, next)
+        {
+            __quota_dentry_free(dentry);
+        }
     }
 
     return 0;
@@ -1839,9 +1853,7 @@ quota_writev(call_frame_t *frame, xlator_t *this, fd_t *fd,
     quota_inode_ctx_t *ctx = NULL;
     quota_dentry_t *dentry = NULL, *tmp = NULL;
     call_stub_t *stub = NULL;
-    struct list_head head = {
-        0,
-    };
+    struct list_head head;
     inode_t *par_inode = NULL;
 
     priv = this->private;
@@ -1881,9 +1893,13 @@ quota_writev(call_frame_t *frame, xlator_t *this, fd_t *fd,
     priv = this->private;
     GF_VALIDATE_OR_GOTO(this->name, priv, unwind);
 
-    size = iov_length(vector, count);
-
     parents = quota_add_parents_from_ctx(ctx, &head);
+    if (parents == -1) {
+        op_errno = errno;
+        goto unwind;
+    }
+
+    size = iov_length(vector, count);
 
     LOCK(&local->lock);
     {
@@ -4805,6 +4821,10 @@ quota_fallocate(call_frame_t *frame, xlator_t *this, fd_t *fd, int32_t mode,
     GF_VALIDATE_OR_GOTO(this->name, priv, unwind);
 
     parents = quota_add_parents_from_ctx(ctx, &head);
+    if (parents == -1) {
+        op_errno = errno;
+        goto unwind;
+    }
 
     /*
      * Note that by using len as the delta we're assuming the range from