callbacks: make the channel accept callback more logical

Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

include/libssh/callbacks.h

@@ -178,13 +178,12 @@ typedef int (*ssh_service_request_callback) (ssh_session session, const char *se
 /**
  * @brief Handles an SSH new channel open session request
  * @param session current session handler
- * @param channel Channel that will be allocated to this channel
  * @param userdata Userdata to be passed to the callback function.
- * @returns 0 if the request is to be allowed
- * @returns -1 if the request should not be allowed
- * @warning if the request is denied by the callback, the channel will be deallocated.
+ * @returns a valid ssh_channel handle if the request is to be allowed
+ * @returns NULL if the request should not be allowed
+ * @warning The channel pointer returned by this callback must be closed by the application.
  */
-typedef int (*ssh_channel_open_request_session_callback) (ssh_session session, ssh_channel channel, void *userdata);
+typedef ssh_channel (*ssh_channel_open_request_session_callback) (ssh_session session, void *userdata);
 
 
 /**
@@ -476,7 +475,7 @@ typedef int (*ssh_channel_pty_request_callback) (ssh_session session,
  * @brief SSH channel Shell request from a client.
  * @param channel the channel
  * @param userdata Userdata to be passed to the callback function.
- * @returns 0 if the pty request is accepted
+ * @returns 0 if the shell request is accepted
  * @returns 1 if the request is denied
  */
 typedef int (*ssh_channel_shell_request_callback) (ssh_session session,

src/messages.c

@@ -121,16 +121,12 @@ static int ssh_execute_server_callbacks(ssh_session session, ssh_message msg){
 		case SSH_REQUEST_CHANNEL_OPEN:
 			if (msg->channel_request_open.type == SSH_CHANNEL_SESSION){
 				if(ssh_callbacks_exists(session->server_callbacks, channel_open_request_session_function)){
-					channel = ssh_channel_new(session);
-					rc = session->server_callbacks->channel_open_request_session_function(session, channel,
+					channel = session->server_callbacks->channel_open_request_session_function(session,
 							session->server_callbacks->userdata);
-					if(rc==0) {
+					if(channel != NULL) {
 						rc = ssh_message_channel_request_open_reply_accept_channel(msg, channel);
-						if (rc == SSH_ERROR)
-							ssh_channel_free(channel);
 						return SSH_OK;
 					} else {
-						ssh_channel_free(channel);
 						ssh_message_reply_default(msg);
 					}
 					return SSH_OK;