nbd: Improve error messages

This patch makes use of the Error object for nbd_receive_negotiate() so
that errors during negotiation look nicer.

Furthermore, this patch adds an additional error message if the received
magic was wrong, but would be correct for the other protocol version,
respectively: So if an export name was specified, but the NBD server
magic corresponds to an old handshake, this condition is explicitly
signaled to the user, and vice versa.

As these messages are now part of the "Could not open image" error
message, additional filtering has to be employed in iotest 083, which
this patch does as well.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 6e1c97cad0b9c52382436a17781980b4f24ae6b2..28bfb62bede6351a7949513b6d9456f017007279 100644 (file)
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -373,7 +373,7 @@ void nbd_client_session_close(NbdClientSession *client)
 }
 
 int nbd_client_session_init(NbdClientSession *client, BlockDriverState *bs,
-    int sock, const char *export)
+                            int sock, const char *export, Error **errp)
 {
     int ret;
 
@@ -382,7 +382,7 @@ int nbd_client_session_init(NbdClientSession *client, BlockDriverState *bs,
     qemu_set_block(sock);
     ret = nbd_receive_negotiate(sock, export,
                                 &client->nbdflags, &client->size,
-                                &client->blocksize);
+                                &client->blocksize, errp);
     if (ret < 0) {
         logout("Failed to negotiate with the NBD server\n");
         closesocket(sock);

diff --git a/block/nbd-client.h b/block/nbd-client.h
index cd478f3a987947d34169e8f20cc0fcae6d5c7b02..cfeecc2775c583ecbacf13db3f2fa7ce5f42fe8b 100644 (file)
--- a/block/nbd-client.h
+++ b/block/nbd-client.h
@@ -36,7 +36,7 @@ typedef struct NbdClientSession {
 } NbdClientSession;
 
 int nbd_client_session_init(NbdClientSession *client, BlockDriverState *bs,
-                            int sock, const char *export_name);
+                            int sock, const char *export_name, Error **errp);
 void nbd_client_session_close(NbdClientSession *client);
 
 int nbd_client_session_co_discard(NbdClientSession *client, int64_t sector_num,

diff --git a/block/nbd.c b/block/nbd.c
index 04cc8450762a8a6645dbb770e86550347c612567..2e208317156d6380e35da0cb8e6fb75fc301c5f7 100644 (file)
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -271,7 +271,7 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* NBD handshake */
-    result = nbd_client_session_init(&s->client, bs, sock, export);
+    result = nbd_client_session_init(&s->client, bs, sock, export, errp);
     g_free(export);
     return result;
 }

diff --git a/include/block/nbd.h b/include/block/nbd.h
index 348302c90b8b1d3ff16aa371d3fccc05aabc340b..b75959556c181b994d2693655c43f054bf4a8263 100644 (file)
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -75,7 +75,7 @@ enum {
 
 ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);
 int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
-                          off_t *size, size_t *blocksize);
+                          off_t *size, size_t *blocksize, Error **errp);
 int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize);
 ssize_t nbd_send_request(int csock, struct nbd_request *request);
 ssize_t nbd_receive_reply(int csock, struct nbd_reply *reply);

diff --git a/nbd.c b/nbd.c
index 53cf82be0b2c91ac6c3fd47fd02bc77bdadea727..e56afbc1621c05464678de69c9815e9d4d6803a5 100644 (file)
--- a/nbd.c
+++ b/nbd.c
@@ -494,7 +494,7 @@ fail:
 }
 
 int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
-                          off_t *size, size_t *blocksize)
+                          off_t *size, size_t *blocksize, Error **errp)
 {
     char buf[256];
     uint64_t magic, s;
@@ -506,13 +506,13 @@ int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
     rc = -EINVAL;
 
     if (read_sync(csock, buf, 8) != 8) {
-        LOG("read failed");
+        error_setg(errp, "Failed to read data");
         goto fail;
     }
 
     buf[8] = '\0';
     if (strlen(buf) == 0) {
-        LOG("server connection closed");
+        error_setg(errp, "Server connection closed unexpectedly");
         goto fail;
     }
 
@@ -527,12 +527,12 @@ int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
           qemu_isprint(buf[7]) ? buf[7] : '.');
 
     if (memcmp(buf, "NBDMAGIC", 8) != 0) {
-        LOG("Invalid magic received");
+        error_setg(errp, "Invalid magic received");
         goto fail;
     }
 
     if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
-        LOG("read failed");
+        error_setg(errp, "Failed to read magic");
         goto fail;
     }
     magic = be64_to_cpu(magic);
@@ -545,52 +545,60 @@ int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
 
         TRACE("Checking magic (opts_magic)");
         if (magic != NBD_OPTS_MAGIC) {
-            LOG("Bad magic received");
+            if (magic == NBD_CLIENT_MAGIC) {
+                error_setg(errp, "Server does not support export names");
+            } else {
+                error_setg(errp, "Bad magic received");
+            }
             goto fail;
         }
         if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
-            LOG("flags read failed");
+            error_setg(errp, "Failed to read server flags");
             goto fail;
         }
         *flags = be16_to_cpu(tmp) << 16;
         /* reserved for future use */
         if (write_sync(csock, &reserved, sizeof(reserved)) !=
             sizeof(reserved)) {
-            LOG("write failed (reserved)");
+            error_setg(errp, "Failed to read reserved field");
             goto fail;
         }
         /* write the export name */
         magic = cpu_to_be64(magic);
         if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
-            LOG("write failed (magic)");
+            error_setg(errp, "Failed to send export name magic");
             goto fail;
         }
         opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
         if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
-            LOG("write failed (opt)");
+            error_setg(errp, "Failed to send export name option number");
             goto fail;
         }
         namesize = cpu_to_be32(strlen(name));
         if (write_sync(csock, &namesize, sizeof(namesize)) !=
             sizeof(namesize)) {
-            LOG("write failed (namesize)");
+            error_setg(errp, "Failed to send export name length");
             goto fail;
         }
         if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) {
-            LOG("write failed (name)");
+            error_setg(errp, "Failed to send export name");
             goto fail;
         }
     } else {
         TRACE("Checking magic (cli_magic)");
 
         if (magic != NBD_CLIENT_MAGIC) {
-            LOG("Bad magic received");
+            if (magic == NBD_OPTS_MAGIC) {
+                error_setg(errp, "Server requires an export name");
+            } else {
+                error_setg(errp, "Bad magic received");
+            }
             goto fail;
         }
     }
 
     if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) {
-        LOG("read failed");
+        error_setg(errp, "Failed to read export length");
         goto fail;
     }
     *size = be64_to_cpu(s);
@@ -599,19 +607,19 @@ int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
 
     if (!name) {
         if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) {
-            LOG("read failed (flags)");
+            error_setg(errp, "Failed to read export flags");
             goto fail;
         }
         *flags = be32_to_cpup(flags);
     } else {
         if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
-            LOG("read failed (tmp)");
+            error_setg(errp, "Failed to read export flags");
             goto fail;
         }
         *flags |= be32_to_cpu(tmp);
     }
     if (read_sync(csock, &buf, 124) != 124) {
-        LOG("read failed (buf)");
+        error_setg(errp, "Failed to read reserved block");
         goto fail;
     }
     rc = 0;

diff --git a/qemu-nbd.c b/qemu-nbd.c
index d222512412f52dce681fc9db833287d3c8fcd14d..4d8df0838595411d171e1d5eb178a383ac88bcc8 100644 (file)
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -284,6 +284,7 @@ static void *nbd_client_thread(void *arg)
     int fd, sock;
     int ret;
     pthread_t show_parts_thread;
+    Error *local_error = NULL;
 
     sock = unix_socket_outgoing(sockpath);
     if (sock < 0) {
@@ -291,8 +292,12 @@ static void *nbd_client_thread(void *arg)
     }
 
     ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
-                                &size, &blocksize);
+                                &size, &blocksize, &local_error);
     if (ret < 0) {
+        if (local_error) {
+            fprintf(stderr, "%s\n", error_get_pretty(local_error));
+            error_free(local_error);
+        }
         goto out_socket;
     }
 

diff --git a/tests/qemu-iotests/083 b/tests/qemu-iotests/083
index 991a9d91db9b2e83ab2abea30aa87e468c8ed8a5..1b2d3f1156c2c7df86d6334069c967698d9c1dc7 100755 (executable)
--- a/tests/qemu-iotests/083
+++ b/tests/qemu-iotests/083
@@ -56,7 +56,8 @@ filter_nbd() {
        #
        # Filter out the TCP port number since this changes between runs.
        sed -e 's#^.*nbd\.c:.*##g' \
-           -e 's#nbd:127\.0\.0\.1:[^:]*:#nbd:127\.0\.0\.1:PORT:#g'
+           -e 's#nbd:127\.0\.0\.1:[^:]*:#nbd:127\.0\.0\.1:PORT:#g' \
+            -e 's#\(exportname=foo\|PORT\): Failed to .*$#\1#'
 }
 
 check_disconnect() {

diff --git a/tests/qemu-iotests/083.out b/tests/qemu-iotests/083.out
index fd397f421ffbf51581663f1d563dfbd7b987b1db..8c1441bf4f03345417dc323182a395e74c015aff 100644 (file)
--- a/tests/qemu-iotests/083.out
+++ b/tests/qemu-iotests/083.out
@@ -1,62 +1,52 @@
 QA output created by 083
 === Check disconnect before neg1 ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect after neg1 ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect 8 neg1 ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect 16 neg1 ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect before export ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect after export ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect 4 export ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect 12 export ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect 16 export ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect before neg2 ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect after neg2 ===
@@ -66,14 +56,12 @@ read failed: Input/output error
 
 === Check disconnect 8 neg2 ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect 10 neg2 ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT:exportname=foo
 no file open, try 'help open'
 
 === Check disconnect before request ===
@@ -119,32 +107,27 @@ read 512/512 bytes at offset 0
 
 === Check disconnect before neg-classic ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT
 no file open, try 'help open'
 
 === Check disconnect 8 neg-classic ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT
 no file open, try 'help open'
 
 === Check disconnect 16 neg-classic ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT
 no file open, try 'help open'
 
 === Check disconnect 24 neg-classic ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT
 no file open, try 'help open'
 
 === Check disconnect 28 neg-classic ===
 
-
-qemu-io: can't open device nbd:127.0.0.1:PORT: Could not open image: Invalid argument
+qemu-io: can't open device nbd:127.0.0.1:PORT
 no file open, try 'help open'
 
 === Check disconnect after neg-classic ===