trace-cmd listen: Use copy of host for connect_ip()

Commit Message

Steven Rostedt May 21, 2022, 10:08 p.m. UTC

From: "Steven Rostedt (Google)" <[e-mail]>

If an old trace-cmd only uses v1 in the listen communication, to determine
this a trick is done by passing the v1 CPU communication a -1 followed by
the communication version. V3 and beyond knows this as the version
communication number, but v1 will error out. Then the connection is closed
and v1 is tried anew. (Note, v2 never existed in a release so it can be ignored).

The problem is that on the retry, the host has been updated with via a
strchr(), and modified. The second time around, it will not have the port
number attached to it, so it will fail to communicate.

Fixes: 194467199c076 ("trace-cmd listen: Add vsocket usage")
Signed-off-by: Steven Rostedt (Google) <[e-mail]>
---
 tracecmd/trace-record.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

Patch

diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index c770f698019f..ce20402af7c2 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -3630,7 +3630,7 @@  static int connect_ip(char *thost)
 	char *port;
 	char *p;
 
-	if (!strchr(host, ':')) {
+	if (!strchr(thost, ':')) {
 		server = strdup("localhost");
 		if (!server)
 			die("alloctating server");
@@ -3662,19 +3662,24 @@  static struct tracecmd_msg_handle *setup_network(struct buffer_instance *instanc
 {
 	struct tracecmd_msg_handle *msg_handle = NULL;
 	enum port_type type = instance->port_type;
+	char *thost = strdup(host);
 	int sfd;
 
+	if (!thost)
+		die("Failed to allocate host");
 again:
 	switch (type) {
 	case USE_VSOCK:
-		sfd = connect_vsock(host);
+		sfd = connect_vsock(thost);
 		break;
 	default:
-		sfd = connect_ip(host);
+		sfd = connect_ip(thost);
 	}
 
-	if (sfd < 0)
+	if (sfd < 0) {
+		free(thost);
 		return NULL;
+	}
 
 	if (msg_handle) {
 		msg_handle->fd = sfd;
@@ -3704,6 +3709,7 @@  again:
 			/* reconnect to the server for using the v1 protocol */
 			close(sfd);
 			free(host);
+			host = NULL;
 			goto again;
 		}
 		communicate_with_listener_v3(msg_handle, &instance->client_ports);
@@ -3712,6 +3718,7 @@  again:
 	if (msg_handle->version == V1_PROTOCOL)
 		communicate_with_listener_v1(msg_handle, instance);
 
+	free(thost);
 	return msg_handle;
 }