glusterd / cli: mount-broker service

Mountbroker is configured in glusterd volfile through a DSL
which is restriced enough to be able to appear in the role
of the value of a volfile knob.

Basically the DSL describes set-theorical requirements
against the option set which is sent by the cli (in the
hope of getting a mount with these options).

If the requirements meet and the volume id and the uid
who is to "own" the mount can be unambigously deduced from
the given request, glusterd does the mount with the given
parameters.

The use case of geo-replication is sugared by means of volume
options which then generate a complete mount-broker option set.

Demo:

- add the following option to your glusterd volfile:

    option mountbroker-root /tmp/mbr
    option mountbroker.fool EQL(volfile-id=pop*|user-map-root=*|volfile-server=localhost)&MEET(user-map-root=john|user-map-root=jane)

- before starting glusterd, create /tmp/mbr owned by root with mode 0755

- with cli, do

   $ gluster system:: mount fool volfile-id=pop33 user-map-root=jane volfile-server=localhost

- on succesful completion (volume pop33 exists and is started, jane is a valid username),
  the mount path will be echoed to you

- you can get rid of the mount by

   $ gluster system:: umount <mount-path>

Change-Id: I629cf64add0a45500d05becc3316f67cdb5b42ff
BUG: 3482
Reviewed-on: http://review.gluster.com/128
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

1 files changed, 149 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-handler.c b/xlators/mgmt/glusterd/src/glusterd-handler.c
index 0547694ca..2f486dac6 100644
--- a/xlators/mgmt/glusterd/src/glusterd-handler.c
+++ b/xlators/mgmt/glusterd/src/glusterd-handler.c
@@ -36,6 +36,7 @@
 #include "compat.h"
 #include "compat-errno.h"
 #include "statedump.h"
+#include "run.h"
 #include "glusterd-mem-types.h"
 #include "glusterd.h"
 #include "glusterd-sm.h"
@@ -48,6 +49,7 @@
 #include "xdr-generic.h"
 #include "rpc-clnt.h"
 #include "glusterd-volgen.h"
+#include "glusterd-mountbroker.h"
 
 #include <sys/resource.h>
 #include <inttypes.h>
@@ -1774,6 +1776,151 @@ glusterd_handle_getwd (rpcsvc_request_t *req)
 
 
 int
+glusterd_handle_mount (rpcsvc_request_t *req)
+{
+        gf1_cli_mount_req mnt_req = {0,};
+        gf1_cli_mount_rsp rsp     = {0,};
+        dict_t *dict              = NULL;
+        int ret                   = 0;
+
+        GF_ASSERT (req);
+
+        if (!xdr_to_generic (req->msg[0], &mnt_req, (xdrproc_t)xdr_gf1_cli_mount_req)) {
+                //failed to decode msg;
+                req->rpc_err = GARBAGE_ARGS;
+                rsp.op_ret = -1;
+                rsp.op_errno = EINVAL;
+                goto out;
+        }
+
+        gf_log ("glusterd", GF_LOG_INFO, "Received mount req");
+
+        if (mnt_req.dict.dict_len) {
+                /* Unserialize the dictionary */
+                dict  = dict_new ();
+
+                ret = dict_unserialize (mnt_req.dict.dict_val,
+                                        mnt_req.dict.dict_len,
+                                        &dict);
+                if (ret < 0) {
+                        gf_log ("glusterd", GF_LOG_ERROR,
+                                "failed to "
+                                "unserialize req-buffer to dictionary");
+                        rsp.op_ret = -1;
+                        rsp.op_errno = -EINVAL;
+                        goto out;
+                } else {
+                        dict->extra_stdfree = mnt_req.dict.dict_val;
+                }
+        }
+
+        rsp.op_ret = glusterd_do_mount (mnt_req.label, dict,
+                                        &rsp.path, &rsp.op_errno);
+
+ out:
+        if (!rsp.path)
+                rsp.path = "";
+
+        ret = glusterd_submit_reply (req, &rsp, NULL, 0, NULL,
+                                     (xdrproc_t)xdr_gf1_cli_mount_rsp);
+
+        if (dict)
+                dict_unref (dict);
+        if (*rsp.path)
+                GF_FREE (rsp.path);
+
+        glusterd_friend_sm ();
+        glusterd_op_sm ();
+
+        return ret;
+}
+
+int
+glusterd_handle_umount (rpcsvc_request_t *req)
+{
+        gf1_cli_umount_req umnt_req = {0,};
+        gf1_cli_umount_rsp rsp      = {0,};
+        char *mountbroker_root      = NULL;
+        char mntp[PATH_MAX]         = {0,};
+        char *path                  = NULL;
+        runner_t runner             = {0,};
+        int ret                     = 0;
+        xlator_t *this              = THIS;
+        gf_boolean_t dir_ok         = _gf_false;
+        char *pdir                  = NULL;
+        char *t                     = NULL;
+
+        GF_ASSERT (req);
+        GF_ASSERT (this);
+
+        if (!xdr_to_generic (req->msg[0], &umnt_req, (xdrproc_t)xdr_gf1_cli_umount_req)) {
+                //failed to decode msg;
+                req->rpc_err = GARBAGE_ARGS;
+                rsp.op_ret = -1;
+                goto out;
+        }
+
+        gf_log ("glusterd", GF_LOG_INFO, "Received umount req");
+
+        if (dict_get_str (this->options, "mountbroker-root",
+                          &mountbroker_root) != 0) {
+                rsp.op_errno = ENOENT;
+                goto out;
+        }
+
+        /* check if it is allowed to umount path */
+        path = gf_strdup (umnt_req.path);
+        if (!path) {
+                rsp.op_errno = ENOMEM;
+                goto out;
+        }
+        dir_ok = _gf_false;
+        pdir = dirname (path);
+        t = strtail (pdir, mountbroker_root);
+        if (t && *t == '/') {
+                t = strtail(++t, MB_HIVE);
+                if (t && !*t)
+                        dir_ok = _gf_true;
+        }
+        GF_FREE (path);
+        if (!dir_ok) {
+                rsp.op_errno = EACCES;
+                goto out;
+        }
+
+        runinit (&runner);
+        runner_add_args (&runner, "umount", umnt_req.path, NULL);
+        if (umnt_req.lazy)
+                runner_add_arg (&runner, "-l");
+        rsp.op_ret = runner_run (&runner);
+        if (rsp.op_ret == 0) {
+                if (realpath (umnt_req.path, mntp))
+                        rmdir (mntp);
+                else {
+                        rsp.op_ret = -1;
+                        rsp.op_errno = errno;
+                }
+                if (unlink (umnt_req.path) != 0) {
+                        rsp.op_ret = -1;
+                        rsp.op_errno = errno;
+                }
+        }
+
+ out:
+        if (rsp.op_errno)
+                rsp.op_ret = -1;
+
+        ret = glusterd_submit_reply (req, &rsp, NULL, 0, NULL,
+                                     (xdrproc_t)xdr_gf1_cli_umount_rsp);
+
+        glusterd_friend_sm ();
+        glusterd_op_sm ();
+
+        return ret;
+}
+
+
+int
 glusterd_friend_remove (uuid_t uuid, char *hostname)
 {
         int                           ret = 0;
@@ -2593,6 +2740,8 @@ rpcsvc_actor_t gd_svc_cli_actors[] = {
         [GLUSTER_CLI_LOG_LEVEL]     = {"LOG_LEVEL", GLUSTER_CLI_LOG_LEVEL, glusterd_handle_log_level, NULL, NULL},
         [GLUSTER_CLI_GETWD]         = { "GETWD", GLUSTER_CLI_GETWD, glusterd_handle_getwd, NULL, NULL},
         [GLUSTER_CLI_STATUS_VOLUME]  = {"STATUS_VOLUME", GLUSTER_CLI_STATUS_VOLUME, glusterd_handle_status_volume, NULL, NULL},
+        [GLUSTER_CLI_MOUNT]         = { "MOUNT", GLUSTER_CLI_MOUNT, glusterd_handle_mount, NULL, NULL},
+        [GLUSTER_CLI_UMOUNT]        = { "UMOUNT", GLUSTER_CLI_UMOUNT, glusterd_handle_umount, NULL, NULL},
 
 };