nbd: Use g_autofree in a few places

Thanks to our recent move to use glib's g_autofree, I can join the
bandwagon.  Getting rid of gotos is fun ;)

There are probably more places where we could register cleanup
functions and get rid of more gotos; this patch just focuses on the
labels that existed merely to call g_free.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190824172813.29720-2-eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

block/nbd.c

@@ -1374,7 +1374,7 @@ static bool nbd_has_filename_options_conflict(QDict *options, Error **errp)
 static void nbd_parse_filename(const char *filename, QDict *options,
                                Error **errp)
 {
-    char *file;
+    g_autofree char *file = NULL;
     char *export_name;
     const char *host_spec;
     const char *unixpath;
@@ -1396,7 +1396,7 @@ static void nbd_parse_filename(const char *filename, QDict *options,
     export_name = strstr(file, EN_OPTSTR);
     if (export_name) {
         if (export_name[strlen(EN_OPTSTR)] == 0) {
-            goto out;
+            return;
         }
         export_name[0] = 0; /* truncate 'file' */
         export_name += strlen(EN_OPTSTR);
@@ -1407,11 +1407,11 @@ static void nbd_parse_filename(const char *filename, QDict *options,
     /* extract the host_spec - fail if it's not nbd:... */
     if (!strstart(file, "nbd:", &host_spec)) {
         error_setg(errp, "File name string for NBD must start with 'nbd:'");
-        goto out;
+        return;
     }
 
     if (!*host_spec) {
-        goto out;
+        return;
     }
 
     /* are we a UNIX or TCP socket? */
@@ -1431,9 +1431,6 @@ static void nbd_parse_filename(const char *filename, QDict *options,
     out_inet:
         qapi_free_InetSocketAddress(addr);
     }
-
-out:
-    g_free(file);
 }
 
 static bool nbd_process_legacy_socket_options(QDict *output_options,

nbd/client.c

@@ -247,12 +247,11 @@ static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply,
 static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
                             Error **errp)
 {
-    int ret = -1;
     NBDOptionReply reply;
     uint32_t len;
     uint32_t namelen;
-    char *local_name = NULL;
-    char *local_desc = NULL;
+    g_autofree char *local_name = NULL;
+    g_autofree char *local_desc = NULL;
     int error;
 
     if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) {
@@ -298,7 +297,7 @@ static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
     local_name = g_malloc(namelen + 1);
     if (nbd_read(ioc, local_name, namelen, "export name", errp) < 0) {
         nbd_send_opt_abort(ioc);
-        goto out;
+        return -1;
     }
     local_name[namelen] = '\0';
     len -= namelen;
@@ -306,24 +305,17 @@ static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
         local_desc = g_malloc(len + 1);
         if (nbd_read(ioc, local_desc, len, "export description", errp) < 0) {
             nbd_send_opt_abort(ioc);
-            goto out;
+            return -1;
         }
         local_desc[len] = '\0';
     }
 
     trace_nbd_receive_list(local_name, local_desc ?: "");
-    *name = local_name;
-    local_name = NULL;
+    *name = g_steal_pointer(&local_name);
     if (description) {
-        *description = local_desc;
-        local_desc = NULL;
+        *description = g_steal_pointer(&local_desc);
     }
-    ret = 1;
-
- out:
-    g_free(local_name);
-    g_free(local_desc);
-    return ret;
+    return 1;
 }
 
 

nbd/server.c

@@ -206,7 +206,7 @@ static int GCC_FMT_ATTR(4, 0)
 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
                             Error **errp, const char *fmt, va_list va)
 {
-    char *msg;
+    g_autofree char *msg = NULL;
     int ret;
     size_t len;
 
@@ -216,18 +216,14 @@ nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
     trace_nbd_negotiate_send_rep_err(msg);
     ret = nbd_negotiate_send_rep_len(client, type, len, errp);
     if (ret < 0) {
-        goto out;
+        return ret;
     }
     if (nbd_write(client->ioc, msg, len, errp) < 0) {
         error_prepend(errp, "write failed (error message): ");
-        ret = -EIO;
-    } else {
-        ret = 0;
+        return -EIO;
     }
 
-out:
-    g_free(msg);
-    return ret;
+    return 0;
 }
 
 /* Send an error reply.