[Nbd] [PATCH 2/3] nbd-server: fix setup_serve() to report errors

[Tuomas Räsänen <tuomasjjrasanen@...1258...>]

This commit changes setup_serve() to report its errors via GError object
to its caller. It also add resource deallocation code to return points
to free all local resources correctly. Note that, the previous version
of the setup_serve() did not free its resources properly on error, but
just called functions which terminated the process. This was techincally
a leak, but without any practical significance due to immediate process
termination. However, now that error handling (process termination) is
separeted from error reporting, we must deallocate/free all locally
allocated resources correctly on errors.

Signed-off-by: Tuomas Räsänen <tuomasjjrasanen@...1261...>
---
 nbd-server.c |   77 ++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 53 insertions(+), 24 deletions(-)

diff --git a/nbd-server.c b/nbd-server.c
index b75e290..d0a2e90 100644
--- a/nbd-server.c
+++ b/nbd-server.c
@@ -2382,12 +2382,12 @@ int dosockopts(const int socket, GError **const gerror) {
  *
  * @param serve the server we want to connect.
  **/
-int setup_serve(SERVER *serve) {
+int setup_serve(SERVER *const serve, GError **const gerror) {
 	struct addrinfo hints;
 	struct addrinfo *ai = NULL;
 	gchar *port = NULL;
 	int e;
-        GError *gerror = NULL;
+        int retval = -1;
 
         /* Without this, it's possible that socket == 0, even if it's
          * not initialized at all. And that would be wrong because 0 is
@@ -2422,10 +2422,11 @@ int setup_serve(SERVER *serve) {
 	g_free(port);
 
 	if(e != 0) {
-		fprintf(stderr, "getaddrinfo failed: %s\n", gai_strerror(e));
-		serve->socket = -1;
-		freeaddrinfo(ai);
-		exit(EXIT_FAILURE);
+                g_set_error(gerror, SETUP_ERROR, SETUP_ERROR_GAI,
+                            "failed to open an export socket: "
+                            "failed to get address info: %s",
+                            gai_strerror(e));
+                goto out;
 	}
 
 	if(serve->socket_family == AF_UNSPEC)
@@ -2439,30 +2440,47 @@ int setup_serve(SERVER *serve) {
 			ai->ai_family = AF_INET6_SDP;
 	}
 #endif
-	if ((serve->socket = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol)) < 0)
-		err("socket: %m");
-
-	if (dosockopts(serve->socket, &gerror) == -1) {
-                msg(LOG_ERR, "failed to open export-specific socket: %s",
-                    gerror->message);
-                g_clear_error(&gerror);
-                exit(EXIT_FAILURE);
+	if ((serve->socket = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol)) < 0) {
+                g_set_error(gerror, SETUP_ERROR, SETUP_ERROR_SOCKET,
+                            "failed to open an export socket: "
+                            "failed to create a socket: %s",
+                            strerror(errno));
+                goto out;
+        }
+
+	if (dosockopts(serve->socket, gerror) == -1) {
+                g_prefix_error(gerror, "failed to open an export socket: ");
+                goto out;
         }
 
 	DEBUG("Waiting for connections... bind, ");
 	e = bind(serve->socket, ai->ai_addr, ai->ai_addrlen);
-	if (e != 0 && errno != EADDRINUSE)
-		err("bind: %m");
+	if (e != 0 && errno != EADDRINUSE) {
+                g_set_error(gerror, SETUP_ERROR, SETUP_ERROR_BIND,
+                            "failed to open an export socket: "
+                            "failed to bind an address to a socket: %s",
+                            strerror(errno));
+                goto out;
+        }
 	DEBUG("listen, ");
-	if (listen(serve->socket, 1) < 0)
-		err("listen: %m");
+	if (listen(serve->socket, 1) < 0) {
+                g_set_error(gerror, SETUP_ERROR, SETUP_ERROR_BIND,
+                            "failed to open an export socket: "
+                            "failed to start listening on a socket: %s",
+                            strerror(errno));
+                goto out;
+        }
+
+        retval = serve->servename ? 1 : 0;
+out:
 
+        if (retval == -1 && serve->socket >= 0) {
+                close(serve->socket);
+                serve->socket = -1;
+        }
 	freeaddrinfo (ai);
-	if(serve->servename) {
-		return 1;
-	} else {
-		return 0;
-	}
+
+        return retval;
 }
 
 int open_modern(const gchar *const addr, const gchar *const port,
@@ -2538,7 +2556,18 @@ void setup_servers(GArray *const servers, const gchar *const modernaddr,
 	int want_modern=0;
 
 	for(i=0;i<servers->len;i++) {
-		want_modern |= setup_serve(&(g_array_index(servers, SERVER, i)));
+                GError *gerror = NULL;
+                SERVER *server = &g_array_index(servers, SERVER, i);
+                int ret;
+
+		ret = setup_serve(server, &gerror);
+                if (ret == -1) {
+                        msg(LOG_ERR, "failed to setup servers: %s",
+                            gerror->message);
+                        g_clear_error(&gerror);
+                        exit(EXIT_FAILURE);
+                }
+                want_modern |= ret;
 	}
 	if(want_modern) {
                 GError *gerror = NULL;
-- 
1.7.10.4