rpc: make binding to port 0 as the default if no option is provided

Right now, if no option is provided, the default port is assumed,
which is 24007. Ideally, for 'glusterfsd' processes, it is better
to not assume there are any ports given, so it can start listening
on any port which is available.

This helps us to cleanup the dependencies on glusterd from glusterfsd
at the moment. No changes would be done to glusterd code, but making
the right defaults helps to make glusterfsd more independent process
later.

NOTE: This patch is a reduced version of below set of patches:
 * https://review.gluster.org/14613/ &
 * https://review.gluster.org/14670/ &
 * https://review.gluster.org/14671/

Credits: Prasanna Kumar Kalever <pkalever@redhat.com>

updates: bz#1343926
Change-Id: Ib874e10505e7366dc56ba754458252b67052e653
Signed-off-by: Amar Tumballi <amarts@redhat.com>

1 files changed, 22 insertions, 3 deletions

diff --git a/rpc/rpc-transport/socket/src/socket.c b/rpc/rpc-transport/socket/src/socket.c
index dd3e1e91992..06b5af2e5b2 100644
--- a/rpc/rpc-transport/socket/src/socket.c
+++ b/rpc/rpc-transport/socket/src/socket.c
@@ -861,15 +861,19 @@ static int
 __socket_server_bind(rpc_transport_t *this)
 {
     socket_private_t *priv = NULL;
+    glusterfs_ctx_t *ctx = NULL;
+    cmd_args_t *cmd_args = NULL;
+    struct sockaddr_storage unix_addr = {0};
     int ret = -1;
     int opt = 1;
     int reuse_check_sock = -1;
-    struct sockaddr_storage unix_addr = {0};
 
     GF_VALIDATE_OR_GOTO("socket", this, out);
     GF_VALIDATE_OR_GOTO("socket", this->private, out);
 
     priv = this->private;
+    ctx = this->ctx;
+    cmd_args = &ctx->cmd_args;
 
     ret = setsockopt(priv->sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
 
@@ -901,8 +905,23 @@ __socket_server_bind(rpc_transport_t *this)
                this->myinfo.identifier, strerror(errno));
         if (errno == EADDRINUSE) {
             gf_log(this->name, GF_LOG_ERROR, "Port is already in use");
-
-            ret = -EADDRINUSE;
+        }
+    }
+    if (AF_UNIX != SA(&this->myinfo.sockaddr)->sa_family) {
+        if (getsockname(priv->sock, SA(&this->myinfo.sockaddr),
+                        &this->myinfo.sockaddr_len) == -1) {
+            gf_log(this->name, GF_LOG_WARNING,
+                   "getsockname on (%d) failed (%s)", priv->sock,
+                   strerror(errno));
+            ret = -1;
+            goto out;
+        }
+        if (!cmd_args->brick_port) {
+            cmd_args->brick_port = (int)ntohs(
+                ((struct sockaddr_in *)&this->myinfo.sockaddr)->sin_port);
+            gf_log(this->name, GF_LOG_INFO,
+                   "process started listening on port (%d)",
+                   cmd_args->brick_port);
         }
     }