fuse: flip xattr key from user to trusted namespace for certain

clients.

This is needed for gsyncd/hadoop-plugin running as non-super
user to be able to request extended attributes under trusted
namespace. Request for a key is made under 'user.' namespace
and is flipped by fuse xlator for specific xattr name to the
corresponding 'trusted.' extended attribute.

Both applications set a identifier (client-pid) while doing a
FUSE mount, which is checked by get/set/remove interfaces in
FUSE translator.

Change-Id: I72f77a5dd1ee1d69c8b0e09209449348dbcf879a
BUG: 3701
Reviewed-on: http://review.gluster.com/563
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

7 files changed, 151 insertions, 9 deletions

diff --git a/libglusterfs/src/common-utils.c b/libglusterfs/src/common-utils.c
index e7d54d48b..6a5e2504b 100644
--- a/libglusterfs/src/common-utils.c
+++ b/libglusterfs/src/common-utils.c
@@ -1946,3 +1946,11 @@ get_mem_size ()
 
         return memsize;
 }
+
+
+int
+gf_client_pid_check (gf_client_pid_t npid)
+{
+        return ( (npid > GF_CLIENT_PID_MIN) && (npid < GF_CLIENT_PID_MAX) )
+                ? 0 : -1;
+}
diff --git a/libglusterfs/src/common-utils.h b/libglusterfs/src/common-utils.h
index 2a5e00c5e..6c83a1004 100644
--- a/libglusterfs/src/common-utils.h
+++ b/libglusterfs/src/common-utils.h
@@ -78,7 +78,23 @@ enum _gf_boolean
 	_gf_true = 1
 };
 
+/*
+ * we could have initialized these as +ve values and treated
+ * them as negative while comparing etc.. (which would have
+ * saved us with the pain of assigning values), but since we
+ * only have a couple of clients that use this feature, it's
+ * okay.
+ */
+enum _gf_client_pid
+{
+        GF_CLIENT_PID_MAX    =  0,
+        GF_CLIENT_PID_GSYNCD = -1,
+        GF_CLIENT_PID_HADOOP = -2,
+        GF_CLIENT_PID_MIN    = -3
+};
+
 typedef enum _gf_boolean gf_boolean_t;
+typedef enum _gf_client_pid gf_client_pid_t;
 typedef int (*gf_cmp) (void *, void *);
 
 void gf_global_variable_init(void);
@@ -401,4 +417,5 @@ char *get_host_name (char *word, char **host);
 char *get_path_name (char *word, char **path);
 void gf_path_strip_trailing_slashes (char *path);
 uint64_t get_mem_size ();
+int gf_client_pid_check (gf_client_pid_t npid);
 #endif /* _COMMON_UTILS_H */
diff --git a/xlators/features/marker/src/marker.c b/xlators/features/marker/src/marker.c
index 0faa8be58..0de391c56 100644
--- a/xlators/features/marker/src/marker.c
+++ b/xlators/features/marker/src/marker.c
@@ -256,7 +256,7 @@ call_from_special_client (call_frame_t *frame, xlator_t *this, const char *name)
 
         priv = (marker_conf_t *)this->private;
 
-        if (frame->root->pid != -1 || name == NULL ||
+        if (frame->root->pid != GF_CLIENT_PID_GSYNCD || name == NULL ||
             strcmp (name, MARKER_XATTR_PREFIX "." VOLUME_MARK) != 0) {
                 ret = _gf_false;
                 goto out;
@@ -1765,7 +1765,7 @@ call_from_sp_client_to_reset_tmfile (call_frame_t *frame,
         if (data == NULL)
                 return -1;
 
-        if (frame->root->pid != -1) {
+        if (frame->root->pid != GF_CLIENT_PID_GSYNCD) {
                 op_ret = -1;
                 op_errno = EPERM;
 
diff --git a/xlators/mgmt/glusterd/src/glusterd-mountbroker.c b/xlators/mgmt/glusterd/src/glusterd-mountbroker.c
index f847298c7..b00145f8c 100644
--- a/xlators/mgmt/glusterd/src/glusterd-mountbroker.c
+++ b/xlators/mgmt/glusterd/src/glusterd-mountbroker.c
@@ -268,7 +268,7 @@ const char *georep_mnt_desc_template =
         "SUP("
                 "xlator-option=\\*-dht.assert-no-child-down=true "
                 "volfile-server=localhost "
-                "client-pid=-1 "
+                "client-pid=%d "
                 "volfile-id=%s "
                 "user-map-root=%s "
         ")"
@@ -280,6 +280,7 @@ const char *georep_mnt_desc_template =
 const char *hadoop_mnt_desc_template =
         "SUP("
                 "volfile-server=%s "
+                "client-pid=%d "
                 "volfile-id=%s "
                 "user-map-root=%s "
         ")"
@@ -296,7 +297,7 @@ make_georep_mountspec (gf_mount_spec_t *mspec, const char *volname,
         int ret               = 0;
 
         ret = gf_asprintf (&georep_mnt_desc, georep_mnt_desc_template,
-                           volname, user);
+                           GF_CLIENT_PID_GSYNCD, volname, user);
         if (ret == -1)
                 return ret;
 
@@ -311,7 +312,7 @@ make_ghadoop_mountspec (gf_mount_spec_t *mspec, const char *volname,
         int   ret             = 0;
 
         ret = gf_asprintf (&hadoop_mnt_desc, hadoop_mnt_desc_template,
-                           server, volname, user);
+                           server, GF_CLIENT_PID_HADOOP, volname, user);
         if (ret == -1)
                 return ret;
 
diff --git a/xlators/mount/fuse/src/fuse-bridge.c b/xlators/mount/fuse/src/fuse-bridge.c
index 78bed0480..7e0022d3d 100644
--- a/xlators/mount/fuse/src/fuse-bridge.c
+++ b/xlators/mount/fuse/src/fuse-bridge.c
@@ -2338,6 +2338,7 @@ fuse_setxattr (xlator_t *this, fuse_in_header_t *finh, void *msg)
         fuse_state_t *state = NULL;
         char         *dict_value = NULL;
         int32_t       ret = -1;
+        char *newkey = NULL;
 
         priv = this->private;
 
@@ -2405,13 +2406,20 @@ fuse_setxattr (xlator_t *this, fuse_in_header_t *finh, void *msg)
                 return;
         }
 
+        ret = fuse_flip_xattr_ns (priv, name, &newkey);
+        if (ret) {
+                send_fuse_err (this, finh, ENOMEM);
+                free_fuse_state (state);
+                return;
+        }
+
         dict_value = memdup (value, fsi->size);
-        dict_set (state->dict, (char *)name,
+        dict_set (state->dict, newkey,
                   data_from_dynptr ((void *)dict_value, fsi->size));
         dict_ref (state->dict);
 
         state->flags = fsi->flags;
-        state->name = gf_strdup (name);
+        state->name = newkey;
 
         uuid_copy (state->resolve.gfid, state->loc.inode->gfid);
         state->resolve.path = gf_strdup (state->loc.path);
@@ -2557,6 +2565,8 @@ fuse_getxattr (xlator_t *this, fuse_in_header_t *finh, void *msg)
         fuse_state_t *state = NULL;
         int32_t       ret = -1;
         struct fuse_private *priv = NULL;
+        int rv = 0;
+        char *newkey = NULL;
 
         priv = this->private;
 
@@ -2611,13 +2621,21 @@ fuse_getxattr (xlator_t *this, fuse_in_header_t *finh, void *msg)
                 return;
         }
 
+        rv = fuse_flip_xattr_ns (priv, name, &newkey);
+        if (rv) {
+                send_fuse_err (this, finh, ENOMEM);
+                free_fuse_state (state);
+                goto out;
+        }
+
         state->size = fgxi->size;
-        state->name = gf_strdup (name);
+        state->name = newkey;
 
         uuid_copy (state->resolve.gfid, state->loc.inode->gfid);
         state->resolve.path = gf_strdup (state->loc.path);
 
         fuse_resolve_and_resume (state, fuse_getxattr_resume);
+ out:
         return;
 }
 
@@ -2681,7 +2699,11 @@ fuse_removexattr (xlator_t *this, fuse_in_header_t *finh, void *msg)
         char *name = msg;
 
         fuse_state_t *state = NULL;
+        fuse_private_t *priv = NULL;
         int32_t       ret = -1;
+        char *newkey = NULL;
+
+        priv = this->private;
 
         GET_STATE (this, finh, state);
         ret = fuse_loc_fill (&state->loc, state, finh->nodeid, 0, NULL);
@@ -2696,7 +2718,14 @@ fuse_removexattr (xlator_t *this, fuse_in_header_t *finh, void *msg)
                 return;
         }
 
-        state->name = gf_strdup (name);
+        ret = fuse_flip_xattr_ns (priv, name, &newkey);
+        if (ret) {
+                send_fuse_err (this, finh, ENOMEM);
+                free_fuse_state (state);
+                return;
+        }
+
+        state->name = newkey;
         uuid_copy (state->resolve.gfid, state->loc.inode->gfid);
         state->resolve.path = gf_strdup (state->loc.path);
 
diff --git a/xlators/mount/fuse/src/fuse-bridge.h b/xlators/mount/fuse/src/fuse-bridge.h
index c729c9468..2215ad22f 100644
--- a/xlators/mount/fuse/src/fuse-bridge.h
+++ b/xlators/mount/fuse/src/fuse-bridge.h
@@ -292,4 +292,7 @@ inode_t *fuse_ino_to_inode (uint64_t ino, xlator_t *fuse);
 int fuse_resolve_and_resume (fuse_state_t *state, fuse_resume_fn_t fn);
 int send_fuse_err (xlator_t *this, fuse_in_header_t *finh, int error);
 int fuse_gfid_set (fuse_state_t *state);
+int fuse_flip_xattr_ns (struct fuse_private *priv, char *okey, char **nkey);
+int fuse_flip_user_to_trusted (char *okey, char **nkey);
+int fuse_xattr_alloc_default (char *okey, char **nkey);
 #endif /* _GF_FUSE_BRIDGE_H_ */
diff --git a/xlators/mount/fuse/src/fuse-helpers.c b/xlators/mount/fuse/src/fuse-helpers.c
index 5fe3dc9f4..f40d1d6a5 100644
--- a/xlators/mount/fuse/src/fuse-helpers.c
+++ b/xlators/mount/fuse/src/fuse-helpers.c
@@ -360,5 +360,89 @@ gf_fuse_stat2attr (struct iatt *st, struct fuse_attr *fa)
 #endif
 }
 
+int
+fuse_flip_user_to_trusted (char *okey, char **nkey)
+{
+        int   ret = 0;
+        char *key = NULL;
+
+        key = GF_CALLOC (1, strlen(okey) + 10, gf_common_mt_char);
+        if (!key) {
+                ret = -1;
+                goto out;
+        }
+
+        okey += 5;
+        strncpy(key, "trusted.", 8);
+        strncat(key+8, okey, strlen(okey));
+
+        *nkey = key;
+
+ out:
+        return ret;
+}
+
+int
+fuse_xattr_alloc_default (char *okey, char **nkey)
+{
+        int ret = 0;
 
+        *nkey = gf_strdup (okey);
+        if (!*nkey)
+                ret = -1;
+        return ret;
+}
 
+int
+fuse_flip_xattr_ns (fuse_private_t *priv, char *okey, char **nkey)
+{
+        int             ret       = 0;
+        gf_boolean_t    need_flip = _gf_false;
+        gf_client_pid_t npid      = 0;
+
+        npid = priv->client_pid;
+        if (gf_client_pid_check (npid)) {
+                ret = fuse_xattr_alloc_default (okey, nkey);
+                goto out;
+        }
+
+        switch (npid) {
+                /*
+                 * These two cases will never execute as we check the
+                 * pid range above, but are kept to keep the compiler
+                 * happy.
+                 */
+        case GF_CLIENT_PID_MAX:
+        case GF_CLIENT_PID_MIN:
+                goto out;
+
+        case GF_CLIENT_PID_GSYNCD:
+                /* valid xattr(s): *xtime, volume-mark* */
+                gf_log("glusterfs-fuse", GF_LOG_DEBUG, "PID: %d, checking xattr(s): "
+                       "volume-mark*, *xtime", npid);
+                if ( (strcmp (okey, "user.glusterfs.volume-mark") == 0)
+                     || (fnmatch (okey, "user.glusterfs.volume-mark.*", FNM_PERIOD) == 0)
+                     || (fnmatch ("user.glusterfs.*.xtime", okey, FNM_PERIOD) == 0) )
+                        need_flip = _gf_true;
+                break;
+
+        case GF_CLIENT_PID_HADOOP:
+                /* valid xattr(s): pathinfo */
+                gf_log("glusterfs-fuse", GF_LOG_DEBUG, "PID: %d, checking xattr(s): "
+                       "pathinfo", npid);
+                if (strcmp (okey, "user.glusterfs.pathinfo") == 0)
+                        need_flip = _gf_true;
+                break;
+        }
+
+        if (need_flip) {
+                gf_log ("glusterfs-fuse", GF_LOG_DEBUG, "flipping %s to trusted equivalent",
+                        okey);
+                ret = fuse_flip_user_to_trusted (okey, nkey);
+        } else {
+                /* if we cannot match, continue with what we got */
+                ret = fuse_xattr_alloc_default (okey, nkey);
+        }
+ out:
+        return ret;
+}