gfapi: object handle based API extensions

There is an ongoing effort to integrate NFS Ganesha (
https://github.com/nfs-ganesha/nfs-ganesha/wiki ) with GlusterFS as one of
the file system back ends.

Towards this we need extensions to gfapi that can handle object based
operations. Meaning, instead of using full paths or relative paths from
cwd, it is required that we can work with APIs, like the *at POSIX
variants, to be able to create, lookup, open etc. files and directories.
Hence the objects are the files or directories themselves and we give out
handles to these objects that can be used for further operations.

This code drop is an initial implementation of the proposed APIs.

The new APIs are implemented as glfs_h_XXX variants in the file
glfs-handleops.c to mirror glfs-fops.c style. The code leverages holding
onto inode references and doling these out as opaque/cookie type objects to
the callers, to enable them to be used as handles in other operations.

An fd based approach was considered, but due to the extra footprint that
the fd structure and its counterparts would incur, this was dropped to take
the approach of holding inode references themselves.

Tested by extending glfsxmp.c to invoke and exercise the added APIs, and
further tested with a reference integration of the same as an FSAL with NFS
Ganesha.

Change-Id: I23629c99e905b54070fa2e6565147812e5f3fa5d
BUG: 1016000
Signed-off-by: R.Shyamsundar <srangana@redhat.com>
Reviewed-on: http://review.gluster.org/5936
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 61 insertions, 17 deletions

diff --git a/libglusterfs/src/syncop.h b/libglusterfs/src/syncop.h
index 64350030e..0fc9e14ba 100644
--- a/libglusterfs/src/syncop.h
+++ b/libglusterfs/src/syncop.h
@@ -25,6 +25,13 @@
 #define SYNCENV_PROC_MIN 2
 #define SYNCPROC_IDLE_TIME 600
 
+/*
+ * Flags for syncopctx valid elements
+ */
+#define SYNCOPCTX_UID    0x00000001
+#define SYNCOPCTX_GID    0x00000002
+#define SYNCOPCTX_GROUPS 0x00000004
+
 struct synctask;
 struct syncproc;
 struct syncenv;
@@ -150,6 +157,14 @@ struct syncargs {
 	int                 done;
 };
 
+struct syncopctx {
+        unsigned int valid;  /* valid flags for elements that are set */
+        uid_t        uid;
+        gid_t        gid;
+        int          grpsize;
+        int          ngrps;
+        gid_t       *groups;
+};
 
 #define __yawn(args) do {                                       \
         args->task = synctask_get ();                           \
@@ -242,34 +257,63 @@ void synctask_waitfor (struct synctask *task, int count);
 int synctask_setid (struct synctask *task, uid_t uid, gid_t gid);
 #define SYNCTASK_SETID(uid, gid) synctask_setid (synctask_get(), uid, gid);
 
+int syncopctx_setfsuid (void *uid);
+int syncopctx_setfsgid (void *gid);
+int syncopctx_setfsgroups (int count, const void *groups);
 
 static inline call_frame_t *
 syncop_create_frame (xlator_t *this)
 {
-	call_frame_t  *frame = NULL;
-	int            ngrps = -1;
+	call_frame_t     *frame = NULL;
+	int               ngrps = -1;
+	struct syncopctx *opctx = NULL;
 
 	frame = create_frame (this, this->ctx->pool);
 	if (!frame)
 		return NULL;
 
-	frame->root->pid = getpid();
-	frame->root->uid = geteuid ();
-	frame->root->gid = getegid ();
-        ngrps = getgroups (0, 0);
-	if (ngrps < 0) {
-		STACK_DESTROY (frame->root);
-		return NULL;
-	}
+	frame->root->pid = getpid ();
 
-	if (call_stack_alloc_groups (frame->root, ngrps) != 0) {
-		STACK_DESTROY (frame->root);
-		return NULL;
-	}
+	opctx = syncopctx_getctx ();
+	if (opctx && (opctx->valid & SYNCOPCTX_UID))
+		frame->root->uid = opctx->uid;
+	else
+		frame->root->uid = geteuid ();
 
-	if (getgroups (ngrps, frame->root->groups) < 0) {
-		STACK_DESTROY (frame->root);
-		return NULL;
+	if (opctx && (opctx->valid & SYNCOPCTX_GID))
+		frame->root->gid = opctx->gid;
+	else
+		frame->root->gid = getegid ();
+
+	if (opctx && (opctx->valid & SYNCOPCTX_GROUPS)) {
+		ngrps = opctx->ngrps;
+
+		if (ngrps != 0 && opctx->groups != NULL) {
+			if (call_stack_alloc_groups (frame->root, ngrps) != 0) {
+				STACK_DESTROY (frame->root);
+				return NULL;
+			}
+
+			memcpy (frame->root->groups, opctx->groups,
+				(sizeof (gid_t) * ngrps));
+		}
+	}
+	else {
+		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;