[PATCH 2/2] termquery: specify $HOST in OSC7 working directory report

[Johannes Altmanninger <aclopte@xxxxxxxxx>]

If I do

	client$ cd ~
	client$ ssh -t server zsh
	server% cd /tmp

and then open a new terminal (using ctrl-shift-n or ctrl-shift-t),
I expect the terminal program to be started in ~, not in /tmp.

For this reason, terminals ignore the OSC 7 notification whose hostname
doesn't match the terminal's host system's.

See the discussion in
https://gitlab.freedesktop.org/terminal-wg/specifications/-/issues/20
and, as an example https://codeberg.org/dnkl/foot, commit 7466e87a
(osc: ignore OSC 7 when hostname doesn't match our own hostname,
2020-04-03) .

Support this by reporting $HOST instead of localhost.

URL-escape $HOST; this might be especially useful because this variable
can be arbitrarily changed by the user.

Also, if the user injects path components into the hostname
("HOST=a/b/c"), don't report anything, to avoid reporting garbage.
For consistency, do the same if HOST is missing ("unset HOST").
Alternatively, we could handle these cases by sending "localhost"
or an empty  hostname component. No strong opinion here.
---
 Src/Zle/termquery.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/Src/Zle/termquery.c b/Src/Zle/termquery.c
index 731589722..353acf0f2 100644
--- a/Src/Zle/termquery.c
+++ b/Src/Zle/termquery.c
@@ -777,11 +777,16 @@ write_urlencoded(const char *path_components)
 void
 notify_pwd(void)
 {
+    const char *hostnam;
+
     if (!extension_enabled("integration", "pwd", 11, 1))
 	return;
 
-    /* only "localhost" seems to be much use here as the host */
-    write_loop(SHTTY, "\033]7;file://localhost", 20);
+    if ((hostnam = getsparam("HOST")) == NULL || strchr(hostnam, '/') != NULL)
+	return;
+
+    write_loop(SHTTY, "\033]7;file://", 11);
+    write_urlencoded(hostnam);
     write_urlencoded(pwd);
     write_loop(SHTTY, "\033\\", 2);
 }
-- 
2.51.0.167.g6ad8021821.dirty