core: increase the auxillary group limit to 65536

Make the allocation of groups dynamic and increase the limit
to 65536.

Change-Id: I702364ff460e3a982e44ccbcb3e337cac9c2df51
BUG: 953694
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/5111
Reviewed-by: Xavier Hernandez <xhernandez@datalab.es>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

4 files changed, 50 insertions, 5 deletions

diff --git a/libglusterfs/src/glusterfs.h b/libglusterfs/src/glusterfs.h
index dbb2b58d9..ac0c81267 100644
--- a/libglusterfs/src/glusterfs.h
+++ b/libglusterfs/src/glusterfs.h
@@ -148,7 +148,7 @@
 /* TODO: Keeping it to 200, so that we can fit in 2KB buffer for auth data
  * in RPC server code, if there is ever need for having more aux-gids, then
  * we have to add aux-gid in payload of actors */
-#define GF_MAX_AUX_GROUPS   200
+#define GF_MAX_AUX_GROUPS   65536
 
 #define GF_UUID_BUF_SIZE 50
 
diff --git a/libglusterfs/src/mem-types.h b/libglusterfs/src/mem-types.h
index 4c78f4607..fea54c35e 100644
--- a/libglusterfs/src/mem-types.h
+++ b/libglusterfs/src/mem-types.h
@@ -108,6 +108,7 @@ enum gf_common_mem_types_ {
         gf_common_mt_drc_globals_t        = 92,
         gf_common_mt_drc_rbtree_node_t    = 93,
         gf_common_mt_iov_base_t           = 94,
-        gf_common_mt_end                  = 95,
+        gf_common_mt_groups_t             = 95,
+        gf_common_mt_end                  = 96
 };
 #endif
diff --git a/libglusterfs/src/stack.h b/libglusterfs/src/stack.h
index a91b635e4..0e8b705bd 100644
--- a/libglusterfs/src/stack.h
+++ b/libglusterfs/src/stack.h
@@ -82,6 +82,8 @@ struct _call_frame_t {
         const char      *unwind_to;
 };
 
+#define SMALL_GROUP_COUNT 128
+
 struct _call_stack_t {
         union {
                 struct list_head      all_frames;
@@ -99,7 +101,9 @@ struct _call_stack_t {
         gid_t                         gid;
         pid_t                         pid;
         uint16_t                      ngrps;
-        uint32_t                      groups[GF_MAX_AUX_GROUPS];
+        uint32_t                      groups_small[SMALL_GROUP_COUNT];
+	uint32_t                     *groups_large;
+	uint32_t                     *groups;
         gf_lkowner_t                  lk_owner;
         glusterfs_ctx_t              *ctx;
 
@@ -174,6 +178,9 @@ STACK_DESTROY (call_stack_t *stack)
         while (stack->frames.next) {
                 FRAME_DESTROY (stack->frames.next);
         }
+
+	GF_FREE (stack->groups_large);
+
         mem_put (stack);
 
         if (local)
@@ -370,6 +377,24 @@ STACK_RESET (call_stack_t *stack)
         } while (0)
 
 
+static inline int
+call_stack_alloc_groups (call_stack_t *stack, int ngrps)
+{
+	if (ngrps <= SMALL_GROUP_COUNT) {
+		stack->groups = stack->groups_small;
+	} else {
+		stack->groups_large = GF_CALLOC (sizeof (gid_t), ngrps,
+						 gf_common_mt_groups_t);
+		if (!stack->groups_large)
+			return -1;
+		stack->groups = stack->groups_large;
+	}
+
+	stack->ngrps = ngrps;
+
+	return 0;
+}
+
 static inline call_frame_t *
 copy_frame (call_frame_t *frame)
 {
@@ -393,8 +418,12 @@ copy_frame (call_frame_t *frame)
         newstack->ngrps = oldstack->ngrps;
         newstack->op  = oldstack->op;
         newstack->type = oldstack->type;
+	if (call_stack_alloc_groups (newstack, oldstack->ngrps) != 0) {
+		mem_put (newstack);
+		return NULL;
+	}
         memcpy (newstack->groups, oldstack->groups,
-                sizeof (gid_t) * GF_MAX_AUX_GROUPS);
+                sizeof (gid_t) * oldstack->ngrps);
         newstack->unique = oldstack->unique;
 
         newstack->frames.this = frame->this;
diff --git a/libglusterfs/src/syncop.h b/libglusterfs/src/syncop.h
index 43e71c4f6..c4b339ee7 100644
--- a/libglusterfs/src/syncop.h
+++ b/libglusterfs/src/syncop.h
@@ -240,6 +240,7 @@ static inline call_frame_t *
 syncop_create_frame (xlator_t *this)
 {
 	call_frame_t  *frame = NULL;
+	int            ngrps = -1;
 
 	frame = create_frame (this, this->ctx->pool);
 	if (!frame)
@@ -248,7 +249,21 @@ syncop_create_frame (xlator_t *this)
 	frame->root->pid = getpid();
 	frame->root->uid = geteuid ();
 	frame->root->gid = getegid ();
-        frame->root->ngrps = getgroups (GF_MAX_AUX_GROUPS, frame->root->groups);
+        ngrps = getgroups (0, 0);
+	if (ngrps < 0) {
+		STACK_DESTROY (frame->root);
+		return NULL;
+	}
+
+	if (call_stack_alloc_groups (frame->root, ngrps) != 0) {
+		STACK_DESTROY (frame->root);
+		return NULL;
+	}
+
+	if (getgroups (ngrps, frame->root->groups) < 0) {
+		STACK_DESTROY (frame->root);
+		return NULL;
+	}
 
 	return frame;
 }