[Qemu-devel] [PATCH v2 02/20] nbd: correctly propagate errors

[Paolo Bonzini <pbonzini@redhat.com>]

Before:
    $ ./qemu-io-old
    qemu-io-old> open -r -o file.driver=nbd
    one of path and host must be specified.
    qemu-io-old: can't open device (null): Could not open image: Invalid argument
    $ ./qemu-io-old
    qemu-io-old> open -r -o file.driver=nbd,file.host=foo,file.path=bar
    path and host may not be used at the same time.
    qemu-io-old: can't open device (null): Could not open image: Invalid argument

After:
    $ ./qemu-io
    qemu-io> open -r -o file.driver=nbd
    qemu-io: can't open device (null): one of path and host must be specified.
    $ ./qemu-io
    qemu-io> open -r -o file.driver=nbd,file.host=foo,file.path=bar
    qemu-io: can't open device (null): path and host may not be used at the same time.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block/nbd.c         | 34 ++++++++++++++++------------------
 include/block/nbd.h |  1 -
 nbd.c               | 12 ------------
 3 files changed, 16 insertions(+), 31 deletions(-)

diff --git a/block/nbd.c b/block/nbd.c
index fd89083..69f336b 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -188,19 +188,18 @@ out:
     g_free(file);
 }
 
-static int nbd_config(BDRVNBDState *s, QDict *options, char **export)
+static void nbd_config(BDRVNBDState *s, QDict *options, char **export,
+                       Error **errp)
 {
     Error *local_err = NULL;
 
     if (qdict_haskey(options, "path") == qdict_haskey(options, "host")) {
         if (qdict_haskey(options, "path")) {
-            qerror_report(ERROR_CLASS_GENERIC_ERROR, "path and host may not "
-                          "be used at the same time.");
+            error_setg(errp, "path and host may not be used at the same time.");
         } else {
-            qerror_report(ERROR_CLASS_GENERIC_ERROR, "one of path and host "
-                          "must be specified.");
+            error_setg(errp, "one of path and host must be specified.");
         }
-        return -EINVAL;
+        return;
     }
 
     s->client.is_unix = qdict_haskey(options, "path");
@@ -209,9 +208,8 @@ static int nbd_config(BDRVNBDState *s, QDict *options, char **export)
 
     qemu_opts_absorb_qdict(s->socket_opts, options, &local_err);
     if (error_is_set(&local_err)) {
-        qerror_report_err(local_err);
-        error_free(local_err);
-        return -EINVAL;
+        error_propagate(errp, local_err);
+        return;
     }
 
     if (!qemu_opt_get(s->socket_opts, "port")) {
@@ -222,19 +220,17 @@ static int nbd_config(BDRVNBDState *s, QDict *options, char **export)
     if (*export) {
         qdict_del(options, "export");
     }
-
-    return 0;
 }
 
-static int nbd_establish_connection(BlockDriverState *bs)
+static int nbd_establish_connection(BlockDriverState *bs, Error **errp)
 {
     BDRVNBDState *s = bs->opaque;
     int sock;
 
     if (s->client.is_unix) {
-        sock = unix_socket_outgoing(qemu_opt_get(s->socket_opts, "path"));
+        sock = unix_connect_opts(s->socket_opts, errp, NULL, NULL);
     } else {
-        sock = tcp_socket_outgoing_opts(s->socket_opts);
+        sock = inet_connect_opts(s->socket_opts, errp, NULL, NULL);
         if (sock >= 0) {
             socket_set_nodelay(sock);
         }
@@ -255,17 +251,19 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVNBDState *s = bs->opaque;
     char *export = NULL;
     int result, sock;
+    Error *local_err = NULL;
 
     /* Pop the config into our state object. Exit if invalid. */
-    result = nbd_config(s, options, &export);
-    if (result != 0) {
-        return result;
+    nbd_config(s, options, &export, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return -EINVAL;
     }
 
     /* establish TCP connection, return error if it fails
      * TODO: Configurable retry-until-timeout behaviour.
      */
-    sock = nbd_establish_connection(bs);
+    sock = nbd_establish_connection(bs, errp);
     if (sock < 0) {
         return sock;
     }
diff --git a/include/block/nbd.h b/include/block/nbd.h
index c90f5e4..e10ab82 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -64,7 +64,6 @@ enum {
 ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);
 int tcp_socket_incoming(const char *address, uint16_t port);
 int tcp_socket_incoming_spec(const char *address_and_port);
-int tcp_socket_outgoing_opts(QemuOpts *opts);
 int unix_socket_outgoing(const char *path);
 int unix_socket_incoming(const char *path);
 
diff --git a/nbd.c b/nbd.c
index 030f56b..17ca95b 100644
--- a/nbd.c
+++ b/nbd.c
@@ -199,18 +199,6 @@ static void combine_addr(char *buf, size_t len, const char* address,
     }
 }
 
-int tcp_socket_outgoing_opts(QemuOpts *opts)
-{
-    Error *local_err = NULL;
-    int fd = inet_connect_opts(opts, &local_err, NULL, NULL);
-    if (local_err != NULL) {
-        qerror_report_err(local_err);
-        error_free(local_err);
-    }
-
-    return fd;
-}
-
 int tcp_socket_incoming(const char *address, uint16_t port)
 {
     char address_and_port[128];
-- 
1.8.5.3