From eead0dbc83d4f8e8da21017976a353c513c3b2b3 Mon Sep 17 00:00:00 2001

From: John Snow <jsnow@redhat.com>

Date: Wed, 27 Mar 2019 17:22:46 +0100

Subject: [PATCH 108/163] nbd/client: Split out nbd_receive_one_meta_context()

RH-Author: John Snow <jsnow@redhat.com>

Message-id: <20190327172308.31077-34-jsnow@redhat.com>

Patchwork-id: 85193

O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 33/55] nbd/client: Split out nbd_receive_one_meta_context()

Bugzilla: 1691009

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Max Reitz <mreitz@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: Eric Blake <eblake@redhat.com>

Extract portions of nbd_negotiate_simple_meta_context() to

a new function nbd_receive_one_meta_context() that copies the

pattern of nbd_receive_list() for performing the argument

validation of one reply.  The error message when the server

replies with more than one context changes slightly, but

that shouldn't happen in the common case.

Signed-off-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Message-Id: <20190117193658.16413-13-eblake@redhat.com>

(cherry picked from commit 0182c1aed9e6a9314023c7264c5c264da2f4a4ce)

Signed-off-by: John Snow <jsnow@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 nbd/client.c     | 147 ++++++++++++++++++++++++++++++++++---------------------

 nbd/trace-events |   2 +-

 2 files changed, 91 insertions(+), 58 deletions(-)

diff --git a/nbd/client.c b/nbd/client.c

index 96da68e..c7bb708 100644

--- a/nbd/client.c

+++ b/nbd/client.c

@@ -669,7 +669,86 @@ static int nbd_send_meta_query(QIOChannel *ioc, uint32_t opt,

     return ret;

 }

-/* nbd_negotiate_simple_meta_context:

+/*

+ * nbd_receive_one_meta_context:

+ * Called in a loop to receive and trace one set/list meta context reply.

+ * Pass non-NULL @name or @id to collect results back to the caller, which

+ * must eventually call g_free().

+ * return 1 if name is set and iteration must continue,

+ *        0 if iteration is complete (including if option is unsupported),

+ *        -1 with errp set for any error

+ */

+static int nbd_receive_one_meta_context(QIOChannel *ioc,

+                                        uint32_t opt,

+                                        char **name,

+                                        uint32_t *id,

+                                        Error **errp)

+{

+    int ret;

+    NBDOptionReply reply;

+    char *local_name = NULL;

+    uint32_t local_id;

+

+    if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) {

+        return -1;

+    }

+

+    ret = nbd_handle_reply_err(ioc, &reply, errp);

+    if (ret <= 0) {

+        return ret;

+    }

+

+    if (reply.type == NBD_REP_ACK) {

+        if (reply.length != 0) {

+            error_setg(errp, "Unexpected length to ACK response");

+            nbd_send_opt_abort(ioc);

+            return -1;

+        }

+        return 0;

+    } else if (reply.type != NBD_REP_META_CONTEXT) {

+        error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)",

+                   reply.type, nbd_rep_lookup(reply.type),

+                   NBD_REP_META_CONTEXT, nbd_rep_lookup(NBD_REP_META_CONTEXT));

+        nbd_send_opt_abort(ioc);

+        return -1;

+    }

+

+    if (reply.length <= sizeof(local_id) ||

+        reply.length > NBD_MAX_BUFFER_SIZE) {

+        error_setg(errp, "Failed to negotiate meta context, server "

+                   "answered with unexpected length %" PRIu32,

+                   reply.length);

+        nbd_send_opt_abort(ioc);

+        return -1;

+    }

+

+    if (nbd_read(ioc, &local_id, sizeof(local_id), errp) < 0) {

+        return -1;

+    }

+    local_id = be32_to_cpu(local_id);

+

+    reply.length -= sizeof(local_id);

+    local_name = g_malloc(reply.length + 1);

+    if (nbd_read(ioc, local_name, reply.length, errp) < 0) {

+        g_free(local_name);

+        return -1;

+    }

+    local_name[reply.length] = '\0';

+    trace_nbd_opt_meta_reply(nbd_opt_lookup(opt), local_name, local_id);

+

+    if (name) {

+        *name = local_name;

+    } else {

+        g_free(local_name);

+    }

+    if (id) {

+        *id = local_id;

+    }

+    return 1;

+}

+

+/*

+ * nbd_negotiate_simple_meta_context:

  * Request the server to set the meta context for export @info->name

  * using @info->x_dirty_bitmap with a fallback to "base:allocation",

  * setting @info->context_id to the resulting id. Fail if the server

@@ -690,50 +769,21 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,

      * function should lose the term _simple.

      */

     int ret;

-    NBDOptionReply reply;

     const char *context = info->x_dirty_bitmap ?: "base:allocation";

     bool received = false;

+    char *name = NULL;

     if (nbd_send_meta_query(ioc, NBD_OPT_SET_META_CONTEXT,

                             info->name, context, errp) < 0) {

         return -1;

     }

-    if (nbd_receive_option_reply(ioc, NBD_OPT_SET_META_CONTEXT, &reply,

-                                 errp) < 0)

-    {

+    ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT,

+                                       &name, &info->context_id, errp);

+    if (ret < 0) {

         return -1;

     }

-

-    ret = nbd_handle_reply_err(ioc, &reply, errp);

-    if (ret <= 0) {

-        return ret;

-    }

-

-    if (reply.type == NBD_REP_META_CONTEXT) {

-        char *name;

-

-        if (reply.length != sizeof(info->context_id) + strlen(context)) {

-            error_setg(errp, "Failed to negotiate meta context '%s', server "

-                       "answered with unexpected length %" PRIu32, context,

-                       reply.length);

-            nbd_send_opt_abort(ioc);

-            return -1;

-        }

-

-        if (nbd_read(ioc, &info->context_id, sizeof(info->context_id),

-                     errp) < 0) {

-            return -1;

-        }

-        info->context_id = be32_to_cpu(info->context_id);

-

-        reply.length -= sizeof(info->context_id);

-        name = g_malloc(reply.length + 1);

-        if (nbd_read(ioc, name, reply.length, errp) < 0) {

-            g_free(name);

-            return -1;

-        }

-        name[reply.length] = '\0';

+    if (ret == 1) {

         if (strcmp(context, name)) {

             error_setg(errp, "Failed to negotiate meta context '%s', server "

                        "answered with different context '%s'", context,

@@ -743,36 +793,19 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,

             return -1;

         }

         g_free(name);

-

-        trace_nbd_opt_meta_reply(context, info->context_id);

         received = true;

-        /* receive NBD_REP_ACK */

-        if (nbd_receive_option_reply(ioc, NBD_OPT_SET_META_CONTEXT, &reply,

-                                     errp) < 0)

-        {

+        ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT,

+                                           NULL, NULL, errp);

+        if (ret < 0) {

             return -1;

         }

-

-        ret = nbd_handle_reply_err(ioc, &reply, errp);

-        if (ret <= 0) {

-            return ret;

-        }

     }

-

-    if (reply.type != NBD_REP_ACK) {

-        error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)",

-                   reply.type, nbd_rep_lookup(reply.type),

-                   NBD_REP_ACK, nbd_rep_lookup(NBD_REP_ACK));

+    if (ret != 0) {

+        error_setg(errp, "Server answered with more than one context");

         nbd_send_opt_abort(ioc);

         return -1;

     }

-    if (reply.length) {

-        error_setg(errp, "Unexpected length to ACK response");

-        nbd_send_opt_abort(ioc);

-        return -1;

-    }

-

     return received;

 }

diff --git a/nbd/trace-events b/nbd/trace-events

index 59521e4..b4802c1 100644

--- a/nbd/trace-events

+++ b/nbd/trace-events

@@ -13,7 +13,7 @@ nbd_receive_query_exports_success(const char *wantname) "Found desired export na

 nbd_receive_starttls_new_client(void) "Setting up TLS"

 nbd_receive_starttls_tls_handshake(void) "Starting TLS handshake"

 nbd_opt_meta_request(const char *optname, const char *context, const char *export) "Requesting %s %s for export %s"

-nbd_opt_meta_reply(const char *context, uint32_t id) "Received mapping of context %s to id %" PRIu32

+nbd_opt_meta_reply(const char *optname, const char *context, uint32_t id) "Received %s mapping of %s to id %" PRIu32

 nbd_receive_negotiate(void *tlscreds, const char *hostname) "Receiving negotiation tlscreds=%p hostname=%s"

 nbd_receive_negotiate_magic(uint64_t magic) "Magic is 0x%" PRIx64

 nbd_receive_negotiate_server_flags(uint32_t globalflags) "Global flags are 0x%" PRIx32

-- 

1.8.3.1