rbd: allow client id to be specified in config string

Allow the client id to be specified in the config string via 'id=' so that
users can control who they authenticate as.  Currently they are stuck with
the default ('admin').  This is necessary for anyone using authentication
in their environment.

Signed-off-by: Sage Weil <sage@newdream.net>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/rbd.c b/block/rbd.c
index ce0f6ef..6135fc1 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -169,6 +169,34 @@
     return ret;
 }
 
+static char *qemu_rbd_parse_clientname(const char *conf, char *clientname)
+{
+    const char *p = conf;
+
+    while (*p) {
+        int len;
+        const char *end = strchr(p, ':');
+
+        if (end) {
+            len = end - p;
+        } else {
+            len = strlen(p);
+        }
+
+        if (strncmp(p, "id=", 3) == 0) {
+            len -= 3;
+            strncpy(clientname, p + 3, len);
+            clientname[len] = '\0';
+            return clientname;
+        }
+        if (end == NULL) {
+            break;
+        }
+        p = end + 1;
+    }
+    return NULL;
+}
+
 static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
 {
     char *p, *buf;
@@ -198,19 +226,21 @@
             break;
         }
 
-        if (strcmp(name, "conf")) {
+        if (strcmp(name, "conf") == 0) {
+            ret = rados_conf_read_file(cluster, value);
+            if (ret < 0) {
+                error_report("error reading conf file %s", value);
+                break;
+            }
+        } else if (strcmp(name, "id") == 0) {
+            /* ignore, this is parsed by qemu_rbd_parse_clientname() */
+        } else {
             ret = rados_conf_set(cluster, name, value);
             if (ret < 0) {
                 error_report("invalid conf option %s", name);
                 ret = -EINVAL;
                 break;
             }
-        } else {
-            ret = rados_conf_read_file(cluster, value);
-            if (ret < 0) {
-                error_report("error reading conf file %s", value);
-                break;
-            }
         }
     }
 
@@ -227,6 +257,8 @@
     char name[RBD_MAX_IMAGE_NAME_SIZE];
     char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
     char conf[RBD_MAX_CONF_SIZE];
+    char clientname_buf[RBD_MAX_CONF_SIZE];
+    char *clientname;
     rados_t cluster;
     rados_ioctx_t io_ctx;
     int ret;
@@ -259,7 +291,8 @@
         options++;
     }
 
-    if (rados_create(&cluster, NULL) < 0) {
+    clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
+    if (rados_create(&cluster, clientname) < 0) {
         error_report("error initializing");
         return -EIO;
     }
@@ -385,6 +418,8 @@
     char pool[RBD_MAX_POOL_NAME_SIZE];
     char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
     char conf[RBD_MAX_CONF_SIZE];
+    char clientname_buf[RBD_MAX_CONF_SIZE];
+    char *clientname;
     int r;
 
     if (qemu_rbd_parsename(filename, pool, sizeof(pool),
@@ -398,7 +433,8 @@
         s->snap = g_strdup(snap_buf);
     }
 
-    r = rados_create(&s->cluster, NULL);
+    clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
+    r = rados_create(&s->cluster, clientname);
     if (r < 0) {
         error_report("error initializing");
         return r;