Although defaulting the handshake limit to 10 seconds was a nice QoI
change to weed out intentionally slow clients, it can interfere with
integration testing done with manual NBD_OPT commands over 'nbdsh
--opt-mode'. Expose a command line option to allow the user to alter
the timeout away from the default. This option is unlikely to be used
in enough scenarios to warrant a short option letter.
The option --handshake-limit intentionally differs from the name of
the constant added in commit fb1c2aaa98 (limit instead of max_secs)
and the QMP name to be added in the next commit; this is because
typing a longer command-line name is undesirable and there is
sufficient --help text to document the units.
Signed-off-by: Eric Blake <ebl...@redhat.com>
Message-ID: <20250203222722.650694-5-ebl...@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
---
docs/tools/qemu-nbd.rst | 5 +++++
qemu-nbd.c | 41 ++++++++++++++++++++++++++---------------
2 files changed, 31 insertions(+), 15 deletions(-)
diff --git a/docs/tools/qemu-nbd.rst b/docs/tools/qemu-nbd.rst
index 4f21b7904ac..f82ea5fd77b 100644
--- a/docs/tools/qemu-nbd.rst
+++ b/docs/tools/qemu-nbd.rst
@@ -156,6 +156,11 @@ driver options if :option:`--image-opts` is specified.
Set the NBD volume export description, as a human-readable
string.
+.. option:: --handshake-limit=N
+
+ Set the timeout for a client to successfully complete its handshake
+ to N seconds (default 10), or 0 for no limit.
+
.. option:: -L, --list
Connect as a client and list all details about the exports exposed by
diff --git a/qemu-nbd.c b/qemu-nbd.c
index b30d3ab8de3..05b61da51ea 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -57,19 +57,20 @@
#define HAVE_NBD_DEVICE 0
#endif
-#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
-#define QEMU_NBD_OPT_CACHE 256
-#define QEMU_NBD_OPT_AIO 257
-#define QEMU_NBD_OPT_DISCARD 258
-#define QEMU_NBD_OPT_DETECT_ZEROES 259
-#define QEMU_NBD_OPT_OBJECT 260
-#define QEMU_NBD_OPT_TLSCREDS 261
-#define QEMU_NBD_OPT_IMAGE_OPTS 262
-#define QEMU_NBD_OPT_FORK 263
-#define QEMU_NBD_OPT_TLSAUTHZ 264
-#define QEMU_NBD_OPT_PID_FILE 265
-#define QEMU_NBD_OPT_SELINUX_LABEL 266
-#define QEMU_NBD_OPT_TLSHOSTNAME 267
+#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
+#define QEMU_NBD_OPT_CACHE 256
+#define QEMU_NBD_OPT_AIO 257
+#define QEMU_NBD_OPT_DISCARD 258
+#define QEMU_NBD_OPT_DETECT_ZEROES 259
+#define QEMU_NBD_OPT_OBJECT 260
+#define QEMU_NBD_OPT_TLSCREDS 261
+#define QEMU_NBD_OPT_IMAGE_OPTS 262
+#define QEMU_NBD_OPT_FORK 263
+#define QEMU_NBD_OPT_TLSAUTHZ 264
+#define QEMU_NBD_OPT_PID_FILE 265
+#define QEMU_NBD_OPT_SELINUX_LABEL 266
+#define QEMU_NBD_OPT_TLSHOSTNAME 267
+#define QEMU_NBD_OPT_HANDSHAKE_LIMIT 268
#define MBR_SIZE 512
@@ -80,6 +81,7 @@ static int nb_fds;
static QIONetListener *server;
static QCryptoTLSCreds *tlscreds;
static const char *tlsauthz;
+static int handshake_limit = NBD_DEFAULT_HANDSHAKE_MAX_SECS;
static void usage(const char *name)
{
@@ -101,6 +103,7 @@ static void usage(const char *name)
" -v, --verbose display extra debugging information\n"
" -x, --export-name=NAME expose export by name (default is empty string)\n"
" -D, --description=TEXT export a human-readable description\n"
+" --handshake-limit=N limit client's handshake to N seconds (default
10)\n"
"\n"
"Exposing part of the image:\n"
" -o, --offset=OFFSET offset into the image\n"
@@ -390,8 +393,7 @@ static void nbd_accept(QIONetListener *listener,
QIOChannelSocket *cioc,
nb_fds++;
nbd_update_server_watch();
- /* TODO - expose handshake timeout as command line option */
- nbd_client_new(cioc, NBD_DEFAULT_HANDSHAKE_MAX_SECS,
+ nbd_client_new(cioc, handshake_limit,
tlscreds, tlsauthz, nbd_client_closed, NULL);
}
@@ -569,6 +571,8 @@ int main(int argc, char **argv)
{ "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
{ "export-name", required_argument, NULL, 'x' },
{ "description", required_argument, NULL, 'D' },
+ { "handshake-limit", required_argument, NULL,
+ QEMU_NBD_OPT_HANDSHAKE_LIMIT },
{ "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
{ "tls-hostname", required_argument, NULL, QEMU_NBD_OPT_TLSHOSTNAME },
{ "tls-authz", required_argument, NULL, QEMU_NBD_OPT_TLSAUTHZ },
@@ -815,6 +819,13 @@ int main(int argc, char **argv)
case QEMU_NBD_OPT_SELINUX_LABEL:
selinux_label = optarg;
break;
+ case QEMU_NBD_OPT_HANDSHAKE_LIMIT:
+ if (qemu_strtoi(optarg, NULL, 0, &handshake_limit) < 0 ||
+ handshake_limit < 0) {
+ error_report("Invalid handshake limit '%s'", optarg);
+ exit(EXIT_FAILURE);
+ }
+ break;
}
}
--
2.48.1
