synctask: implement setuid-like SYNCTASK_SETID()

synctasks can now call SYNCTASK_SETID(uid,gid) to set the effective
uid/gid of the frame with which the FOP will be performed.

Once called, the uid/gid is set either till the end of the synctask
or till the next call of SYNCTASK_SETID()

Change-Id: I7eb74f7c473099bcae39310d2ab353d58f8eb2ba
BUG: 884597
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/4269
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Shishir Gowda <sgowda@redhat.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/libglusterfs/src/syncop.c b/libglusterfs/src/syncop.c
index c8a9b5848c1..b15ee31ba07 100644
--- a/libglusterfs/src/syncop.c
+++ b/libglusterfs/src/syncop.c
@@ -173,6 +173,22 @@ synctask_done (struct synctask *task)
 
 
 int
+synctask_setid (struct synctask *task, uid_t uid, gid_t gid)
+{
+	if (!task)
+		return -1;
+
+	if (uid != -1)
+		task->uid = uid;
+
+	if (gid != -1)
+		task->gid = gid;
+
+	return 0;
+}
+
+
+int
 synctask_new (struct syncenv *env, synctask_fn_t fn, synctask_cbk_t cbk,
               call_frame_t *frame, void *opaque)
 {
@@ -201,6 +217,10 @@ synctask_new (struct syncenv *env, synctask_fn_t fn, synctask_cbk_t cbk,
 	newtask->synccbk    = cbk;
         newtask->opaque     = opaque;
 
+	/* default to the uid/gid of the passed frame */
+	newtask->uid = newtask->opframe->root->uid;
+	newtask->gid = newtask->opframe->root->gid;
+
         INIT_LIST_HEAD (&newtask->all_tasks);
 
         if (getcontext (&newtask->ctx) < 0) {
diff --git a/libglusterfs/src/syncop.h b/libglusterfs/src/syncop.h
index 6e900e8d0d9..6b63a7d1585 100644
--- a/libglusterfs/src/syncop.h
+++ b/libglusterfs/src/syncop.h
@@ -59,6 +59,9 @@ struct synctask {
         int                 slept;
 	int                 ret;
 
+	uid_t               uid;
+	gid_t               gid;
+
         ucontext_t          ctx;
 	struct syncproc    *proc;
 
@@ -170,6 +173,11 @@ struct syncargs {
 		else							\
 			frame = create_frame (THIS, THIS->ctx->pool);	\
 									\
+		if (task) {						\
+			frame->root->uid = task->uid;			\
+			frame->root->gid = task->gid;			\
+		}							\
+									\
 		__yawn (stb);						\
                                                                         \
                 STACK_WIND_COOKIE (frame, cbk, (void *)stb, subvol,	\
@@ -195,6 +203,9 @@ int synctask_new (struct syncenv *, synctask_fn_t, synctask_cbk_t, call_frame_t*
 void synctask_wake (struct synctask *task);
 void synctask_yield (struct synctask *task);
 
+int synctask_setid (struct synctask *task, uid_t uid, gid_t gid);
+#define SYNCTASK_SETID(uid, gid) synctask_setid (synctask_get(), uid, gid);
+
 int syncop_lookup (xlator_t *subvol, loc_t *loc, dict_t *xattr_req,
                    /* out */
                    struct iatt *iatt, dict_t **xattr_rsp, struct iatt *parent);