From 7d557c2a53a5baa7d566e5d8ffa467dd1bc382db Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@redhat.com>
Date: Wed, 19 Jul 2017 18:02:01 +0200
Subject: [PATCH 04/17] nbd: make nbd_drop public

RH-Author: Eric Blake <eblake@redhat.com>
Message-id: <20170719180202.23329-4-eblake@redhat.com>
Patchwork-id: 75814
O-Subject: [RHEV-7.4.z qemu-kvm-rhev PATCH 3/4] nbd: make nbd_drop public
Bugzilla: 1473638
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>

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

Following commit will reuse it for nbd server too.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170602150150.258222-3-vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 44298024d30ad36439707b89715a76333f58791b)

 Conflicts:
	nbd/client.c, nbd/nbd_internal.h, nbd/common.c - missing errp
	addition (e44ed99) and bulk rename (d1fdf25)

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 nbd/client.c       | 32 +++-----------------------------
 nbd/common.c       | 26 ++++++++++++++++++++++++++
 nbd/nbd-internal.h |  2 ++
 3 files changed, 31 insertions(+), 29 deletions(-)

diff --git a/nbd/client.c b/nbd/client.c
index 6b74a62..1652f28 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -86,32 +86,6 @@ static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
 
 */
 
-/* Discard length bytes from channel.  Return -errno on failure and 0 on
- * success*/
-static int drop_sync(QIOChannel *ioc, size_t size)
-{
-    ssize_t ret = 0;
-    char small[1024];
-    char *buffer;
-
-    buffer = sizeof(small) >= size ? small : g_malloc(MIN(65536, size));
-    while (size > 0) {
-        ssize_t count = MIN(65536, size);
-        ret = read_sync(ioc, buffer, MIN(65536, size));
-
-        if (ret < 0) {
-            goto cleanup;
-        }
-        size -= count;
-    }
-
- cleanup:
-    if (buffer != small) {
-        g_free(buffer);
-    }
-    return ret;
-}
-
 /* Send an option request.
  *
  * The request is for option @opt, with @data containing @len bytes of
@@ -333,7 +307,7 @@ static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match,
         return -1;
     }
     if (namelen != strlen(want)) {
-        if (drop_sync(ioc, len) < 0) {
+        if (nbd_drop(ioc, len) < 0) {
             error_setg(errp, "failed to skip export name with wrong length");
             nbd_send_opt_abort(ioc);
             return -1;
@@ -349,7 +323,7 @@ static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match,
     }
     name[namelen] = '\0';
     len -= namelen;
-    if (drop_sync(ioc, len) < 0) {
+    if (nbd_drop(ioc, len) < 0) {
         error_setg(errp, "failed to read export description");
         nbd_send_opt_abort(ioc);
         return -1;
@@ -616,7 +590,7 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
     }
 
     TRACE("Size is %" PRIu64 ", export flags %" PRIx16, *size, *flags);
-    if (zeroes && drop_sync(ioc, 124) < 0) {
+    if (zeroes && nbd_drop(ioc, 124) < 0) {
         error_setg(errp, "Failed to read reserved block");
         goto fail;
     }
diff --git a/nbd/common.c b/nbd/common.c
index 4db45b3..9a54010 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -71,6 +71,32 @@ ssize_t nbd_wr_syncv(QIOChannel *ioc,
     return done;
 }
 
+/* Discard length bytes from channel.  Return -errno on failure and 0 on
+ * success */
+int nbd_drop(QIOChannel *ioc, size_t size)
+{
+    ssize_t ret = 0;
+    char small[1024];
+    char *buffer;
+
+    buffer = sizeof(small) >= size ? small : g_malloc(MIN(65536, size));
+    while (size > 0) {
+        ssize_t count = MIN(65536, size);
+        ret = read_sync(ioc, buffer, MIN(65536, size));
+
+        if (ret < 0) {
+            goto cleanup;
+        }
+        size -= count;
+    }
+
+ cleanup:
+    if (buffer != small) {
+        g_free(buffer);
+    }
+    return ret;
+}
+
 
 void nbd_tls_handshake(QIOTask *task,
                        void *opaque)
diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h
index e6bbc7c..c02378c 100644
--- a/nbd/nbd-internal.h
+++ b/nbd/nbd-internal.h
@@ -149,4 +149,6 @@ struct NBDTLSHandshakeData {
 void nbd_tls_handshake(QIOTask *task,
                        void *opaque);
 
+int nbd_drop(QIOChannel *ioc, size_t size);
+
 #endif
-- 
1.8.3.1