From 0caa0a85dd00ad53818b9cc641579462e69fd198 Mon Sep 17 00:00:00 2001
From: des <des@FreeBSD.org>
Date: Fri, 7 Oct 2011 13:10:16 +0000
Subject: Add a -x option that causes ssh-agent(1) to exit when all clients
 have disconnected.

MFC after:	1 week
---
 crypto/openssh/ssh-agent.1 |  4 +++-
 crypto/openssh/ssh-agent.c | 32 +++++++++++++++++++++++++++++---
 2 files changed, 32 insertions(+), 4 deletions(-)

(limited to 'crypto/openssh')

diff --git a/crypto/openssh/ssh-agent.1 b/crypto/openssh/ssh-agent.1
index 7f4942f..b144615 100644
--- a/crypto/openssh/ssh-agent.1
+++ b/crypto/openssh/ssh-agent.1
@@ -44,7 +44,7 @@
 .Sh SYNOPSIS
 .Nm ssh-agent
 .Op Fl c | s
-.Op Fl d
+.Op Fl dx
 .Op Fl a Ar bind_address
 .Op Fl t Ar life
 .Op Ar command Op Ar arg ...
@@ -103,6 +103,8 @@ A lifetime specified for an identity with
 .Xr ssh-add 1
 overrides this value.
 Without this option the default maximum lifetime is forever.
+.It Fl x
+Exit after the last client has disconnected.
 .El
 .Pp
 If a commandline is given, this is executed as a subprocess of the agent.
diff --git a/crypto/openssh/ssh-agent.c b/crypto/openssh/ssh-agent.c
index b75d689..9d4e0c9 100644
--- a/crypto/openssh/ssh-agent.c
+++ b/crypto/openssh/ssh-agent.c
@@ -138,15 +138,34 @@ extern char *__progname;
 /* Default lifetime (0 == forever) */
 static int lifetime = 0;
 
+/*
+ * Client connection count; incremented in new_socket() and decremented in
+ * close_socket().  When it reaches 0, ssh-agent will exit.  Since it is
+ * normally initialized to 1, it will never reach 0.  However, if the -x
+ * option is specified, it is initialized to 0 in main(); in that case,
+ * ssh-agent will exit as soon as it has had at least one client but no
+ * longer has any.
+ */
+static int xcount = 1;
+
 static void
 close_socket(SocketEntry *e)
 {
+	int last = 0;
+
+	if (e->type == AUTH_CONNECTION) {
+		debug("xcount %d -> %d", xcount, xcount - 1);
+		if (--xcount == 0)
+			last = 1;
+	}
 	close(e->fd);
 	e->fd = -1;
 	e->type = AUTH_UNUSED;
 	buffer_free(&e->input);
 	buffer_free(&e->output);
 	buffer_free(&e->request);
+	if (last)
+		cleanup_exit(0);
 }
 
 static void
@@ -901,6 +920,10 @@ new_socket(sock_type type, int fd)
 {
 	u_int i, old_alloc, new_alloc;
 
+	if (type == AUTH_CONNECTION) {
+		debug("xcount %d -> %d", xcount, xcount + 1);
+		++xcount;
+	}
 	set_nonblock(fd);
 
 	if (fd > max_fd)
@@ -1121,6 +1144,7 @@ usage(void)
 	fprintf(stderr, "  -d          Debug mode.\n");
 	fprintf(stderr, "  -a socket   Bind agent socket to given name.\n");
 	fprintf(stderr, "  -t life     Default identity lifetime (seconds).\n");
+	fprintf(stderr, "  -x          Exit when the last client disconnects.\n");
 	exit(1);
 }
 
@@ -1162,7 +1186,7 @@ main(int ac, char **av)
 	__progname = ssh_get_progname(av[0]);
 	seed_rng();
 
-	while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
+	while ((ch = getopt(ac, av, "cdksa:t:x")) != -1) {
 		switch (ch) {
 		case 'c':
 			if (s_flag)
@@ -1191,6 +1215,9 @@ main(int ac, char **av)
 				usage();
 			}
 			break;
+		case 'x':
+			xcount = 0;
+			break;
 		default:
 			usage();
 		}
@@ -1350,8 +1377,7 @@ skip:
 	if (ac > 0)
 		parent_alive_interval = 10;
 	idtab_init();
-	if (!d_flag)
-		signal(SIGINT, SIG_IGN);
+	signal(SIGINT, d_flag ? cleanup_handler : SIG_IGN);
 	signal(SIGPIPE, SIG_IGN);
 	signal(SIGHUP, cleanup_handler);
 	signal(SIGTERM, cleanup_handler);
-- 
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