From 98cd8e4cad3afbc542de665e9d025d12b560bc6b Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 8 Mar 2022 11:28:40 +0000
Subject: Add formats for client and server UID and user (for multiuser
 setups).

---
 cmd-list-clients.c |  2 ++
 format.c           | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 proc.c             | 11 ++++++++++
 3 files changed, 73 insertions(+)

diff --git a/cmd-list-clients.c b/cmd-list-clients.c
index a5b7d147..53a99178 100644
--- a/cmd-list-clients.c
+++ b/cmd-list-clients.c
@@ -31,6 +31,8 @@
 #define LIST_CLIENTS_TEMPLATE						\
 	"#{client_name}: #{session_name} "				\
 	"[#{client_width}x#{client_height} #{client_termname}] "	\
+	"#{?#{!=:#{client_uid},#{uid}},"				\
+	"[user #{?client_user,#{client_user},#{client_uid},}] ,}"	\
 	"#{?client_flags,(,}#{client_flags}#{?client_flags,),}"
 
 static enum cmd_retval	cmd_list_clients_exec(struct cmd *, struct cmdq_item *);
diff --git a/format.c b/format.c
index 15f3179c..f381a0ec 100644
--- a/format.c
+++ b/format.c
@@ -24,6 +24,7 @@
 #include <fnmatch.h>
 #include <libgen.h>
 #include <math.h>
+#include <pwd.h>
 #include <regex.h>
 #include <stdarg.h>
 #include <stdlib.h>
@@ -1387,6 +1388,35 @@ format_cb_client_tty(struct format_tree *ft)
 	return (NULL);
 }
 
+/* Callback for client_uid. */
+static void *
+format_cb_client_uid(struct format_tree *ft)
+{
+	uid_t	uid;
+
+	if (ft->c != NULL) {
+		uid = proc_get_peer_uid(ft->c->peer);
+		if (uid != (uid_t)-1)
+			return (format_printf("%ld", (long)uid));
+	}
+	return (NULL);
+}
+
+/* Callback for client_user. */
+static void *
+format_cb_client_user(struct format_tree *ft)
+{
+	uid_t		 uid;
+	struct passwd	*pw;
+
+	if (ft->c != NULL) {
+		uid = proc_get_peer_uid(ft->c->peer);
+		if (uid != (uid_t)-1 && (pw = getpwuid(uid)) != NULL)
+			return (xstrdup(pw->pw_name));
+	}
+	return (NULL);
+}
+
 /* Callback for client_utf8. */
 static void *
 format_cb_client_utf8(struct format_tree *ft)
@@ -2521,6 +2551,24 @@ format_cb_tree_mode_format(__unused struct format_tree *ft)
 	return (xstrdup(window_tree_mode.default_format));
 }
 
+/* Callback for uid. */
+static void *
+format_cb_uid(__unused struct format_tree *ft)
+{
+	return (format_printf("%ld", (long)getuid()));
+}
+
+/* Callback for user. */
+static void *
+format_cb_user(__unused struct format_tree *ft)
+{
+	struct passwd	*pw;
+
+	if ((pw = getpwuid(getuid())) != NULL)
+		return (xstrdup(pw->pw_name));
+	return NULL;
+}
+
 /* Format table type. */
 enum format_table_type {
 	FORMAT_TABLE_STRING,
@@ -2627,6 +2675,12 @@ static const struct format_table_entry format_table[] = {
 	{ "client_tty", FORMAT_TABLE_STRING,
 	  format_cb_client_tty
 	},
+	{ "client_uid", FORMAT_TABLE_STRING,
+	  format_cb_client_uid
+	},
+	{ "client_user", FORMAT_TABLE_STRING,
+	  format_cb_client_user
+	},
 	{ "client_utf8", FORMAT_TABLE_STRING,
 	  format_cb_client_utf8
 	},
@@ -2906,6 +2960,12 @@ static const struct format_table_entry format_table[] = {
 	{ "tree_mode_format", FORMAT_TABLE_STRING,
 	  format_cb_tree_mode_format
 	},
+	{ "uid", FORMAT_TABLE_STRING,
+	  format_cb_uid
+	},
+	{ "user", FORMAT_TABLE_STRING,
+	  format_cb_user
+	},
 	{ "version", FORMAT_TABLE_STRING,
 	  format_cb_version
 	},
diff --git a/proc.c b/proc.c
index 9412cec0..9dcb042e 100644
--- a/proc.c
+++ b/proc.c
@@ -55,6 +55,7 @@ struct tmuxpeer {
 
 	struct imsgbuf	 ibuf;
 	struct event	 event;
+	uid_t		 uid;
 
 	int		 flags;
 #define PEER_BAD 0x1
@@ -296,6 +297,7 @@ proc_add_peer(struct tmuxproc *tp, int fd,
     void (*dispatchcb)(struct imsg *, void *), void *arg)
 {
 	struct tmuxpeer	*peer;
+	gid_t		 gid;
 
 	peer = xcalloc(1, sizeof *peer);
 	peer->parent = tp;
@@ -306,6 +308,9 @@ proc_add_peer(struct tmuxproc *tp, int fd,
 	imsg_init(&peer->ibuf, fd);
 	event_set(&peer->event, fd, EV_READ, proc_event_cb, peer);
 
+	if (getpeereid(fd, &peer->uid, &gid) != 0)
+		peer->uid = (uid_t)-1;
+
 	log_debug("add peer %p: %d (%p)", peer, fd, arg);
 	TAILQ_INSERT_TAIL(&tp->peers, peer, entry);
 
@@ -361,3 +366,9 @@ proc_fork_and_daemon(int *fd)
 		return (pid);
 	}
 }
+
+uid_t
+proc_get_peer_uid(struct tmuxpeer *peer)
+{
+	return (peer->uid);
+}
-- 
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