From 2b331084b4c69dafac6e2bb1d5b02193666cf0e0 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicm@openbsd.org>
Date: Wed, 29 Jul 2009 17:03:16 +0000
Subject: [PATCH] Add an additional heuristic to work out the current session
 when run from the command line. The name of all slave ptys in the server is
 known, so if the client was run on a tty, look for any sessions containing
 that tty and use the most recently created.

This is more reliable than looking at $TMUX if windows have been moved or
linked between sessions.
---
 cmd.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 46 insertions(+), 7 deletions(-)

diff --git a/cmd.c b/cmd.c
index 9fda3dcc..820521d0 100644
--- a/cmd.c
+++ b/cmd.c
@@ -103,7 +103,7 @@ const struct cmd_entry *cmd_table[] = {
 	NULL
 };
 
-struct session	*cmd_newest_session(void);
+struct session	*cmd_newest_session(struct sessions *);
 struct client	*cmd_lookup_client(const char *);
 struct session	*cmd_lookup_session(const char *, int *);
 struct winlink	*cmd_lookup_window(struct session *, const char *, int *);
@@ -281,18 +281,57 @@ cmd_print(struct cmd *cmd, char *buf, size_t len)
 
 /*
  * Figure out the current session. Use: 1) the current session, if the command
- * context has one; 2) the session specified in the TMUX variable from the
- * environment (as passed from the client); 3) the newest session.
+ * context has one; 2) the session containing the pty of the calling client, if
+ * any 3) the session specified in the TMUX variable from the environment (as
+ * passed from the client); 3) the newest session.
  */
 struct session *
 cmd_current_session(struct cmd_ctx *ctx)
 {
 	struct msg_command_data	*data = ctx->msgdata;
+	struct client		*c = ctx->cmdclient;
 	struct session		*s;
+	struct sessions		 ss;
+	struct winlink		*wl;
+	struct window_pane	*wp;
+	u_int			 i;
+	int			 found;
 
 	if (ctx->cursession != NULL)
 		return (ctx->cursession);
 
+	/*
+	 * If the name of the calling client's pty is know, build a list of the
+	 * sessions that contain it and if any choose either the first or the
+	 * newest.
+	 */
+	if (c != NULL && c->tty.path != NULL) {
+		ARRAY_INIT(&ss);
+		for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
+			if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
+				continue;
+			found = 0;
+			RB_FOREACH(wl, winlinks, &s->windows) {
+				TAILQ_FOREACH(wp, &wl->window->panes, entry) {
+					if (strcmp(wp->tty, c->tty.path) == 0) {
+						found = 1;
+						break;
+					}
+				}
+				if (found)
+					break;
+			}
+			if (found)
+				ARRAY_ADD(&ss, s);
+		}
+
+		s = cmd_newest_session(&ss);
+		ARRAY_FREE(&ss);
+		if (s != NULL)
+			return (s);
+	}
+
+	/* Use the session from the TMUX environment variable. */
 	if (data != NULL && data->pid != -1) {
 		if (data->pid != getpid())
 			return (NULL);
@@ -303,20 +342,20 @@ cmd_current_session(struct cmd_ctx *ctx)
 		return (s);
 	}
 
-	return (cmd_newest_session());
+	return (cmd_newest_session(&sessions));
 }
 
 /* Find the newest session. */
 struct session *
-cmd_newest_session(void)
+cmd_newest_session(struct sessions *ss)
 {
 	struct session	*s, *snewest;
 	struct timeval	*tv = NULL;
 	u_int		 i;
 
 	snewest = NULL;
-	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
-		if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
+	for (i = 0; i < ARRAY_LENGTH(ss); i++) {
+		if ((s = ARRAY_ITEM(ss, i)) == NULL)
 			continue;
 
 		if (tv == NULL || timercmp(&s->tv, tv, >)) {