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authorEric Blake <eblake@redhat.com>2019-01-17 13:36:52 -0600
committerEric Blake <eblake@redhat.com>2019-01-21 15:49:52 -0600
commitb3c9d33bc4e7c2ab2828b16ebc96f0414b0f1acf (patch)
treedd9a0c1b29671058f4cdbf8d8b668eb3d23d4898 /nbd
parent10b89988d6b0f5f2aed794bed5b4e774858548f4 (diff)
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nbd/client: Pull out oldstyle size determination
Another refactoring creating nbd_negotiate_finish_oldstyle() for further reuse during 'qemu-nbd --list'. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Richard W.M. Jones <rjones@redhat.com> Message-Id: <20190117193658.16413-16-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Diffstat (limited to 'nbd')
-rw-r--r--nbd/client.c49
1 files changed, 32 insertions, 17 deletions
diff --git a/nbd/client.c b/nbd/client.c
index 77cc123..6829c68 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -814,7 +814,7 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,
* Start the handshake to the server. After a positive return, the server
* is ready to accept additional NBD_OPT requests.
* Returns: negative errno: failure talking to server
- * 0: server is oldstyle, client must still parse export size
+ * 0: server is oldstyle, must call nbd_negotiate_finish_oldstyle
* 1: server is newstyle, but can only accept EXPORT_NAME
* 2: server is newstyle, but lacks structured replies
* 3: server is newstyle and set up for structured replies
@@ -921,6 +921,36 @@ static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
}
/*
+ * nbd_negotiate_finish_oldstyle:
+ * Populate @info with the size and export flags from an oldstyle server,
+ * but does not consume 124 bytes of reserved zero padding.
+ * Returns 0 on success, -1 with @errp set on failure
+ */
+static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info,
+ Error **errp)
+{
+ uint32_t oldflags;
+
+ if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
+ error_prepend(errp, "Failed to read export length: ");
+ return -EINVAL;
+ }
+ info->size = be64_to_cpu(info->size);
+
+ if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {
+ error_prepend(errp, "Failed to read export flags: ");
+ return -EINVAL;
+ }
+ oldflags = be32_to_cpu(oldflags);
+ if (oldflags & ~0xffff) {
+ error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
+ return -EINVAL;
+ }
+ info->flags = oldflags;
+ return 0;
+}
+
+/*
* nbd_receive_negotiate:
* Connect to server, complete negotiation, and move into transmission phase.
* Returns: negative errno: failure talking to server
@@ -933,7 +963,6 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
int result;
bool zeroes;
bool base_allocation = info->base_allocation;
- uint32_t oldflags;
assert(info->name);
trace_nbd_receive_negotiate_name(info->name);
@@ -1006,23 +1035,9 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
error_setg(errp, "Server does not support non-empty export names");
return -EINVAL;
}
-
- if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
- error_prepend(errp, "Failed to read export length: ");
- return -EINVAL;
- }
- info->size = be64_to_cpu(info->size);
-
- if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {
- error_prepend(errp, "Failed to read export flags: ");
- return -EINVAL;
- }
- oldflags = be32_to_cpu(oldflags);
- if (oldflags & ~0xffff) {
- error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
+ if (nbd_negotiate_finish_oldstyle(ioc, info, errp) < 0) {
return -EINVAL;
}
- info->flags = oldflags;
break;
default:
return result;