devpts: use max=<count> option on mount

src/lxc/conf.c

@@ -1332,7 +1332,8 @@ static int setup_pivot_root(const struct lxc_rootfs *rootfs)
 static int lxc_setup_devpts(int num_pts)
 {
 	int ret;
-	const char *devpts_mntopts = "newinstance,ptmxmode=0666,mode=0620,gid=5";
+	const char *default_devpts_mntopts = "newinstance,ptmxmode=0666,mode=0620,gid=5";
+	char devpts_mntopts[256];
 
 	if (!num_pts) {
 		DEBUG("no new devpts instance will be mounted since no pts "
@@ -1340,6 +1341,11 @@ static int lxc_setup_devpts(int num_pts)
 		return 0;
 	}
 
+	ret = snprintf(devpts_mntopts, sizeof(devpts_mntopts), "%s,max=%d",
+		       default_devpts_mntopts, num_pts);
+	if (ret < 0 || (size_t)ret >= sizeof(devpts_mntopts))
+		return -1;
+
 	/* Unmount old devpts instance. */
 	ret = access("/dev/pts/ptmx", F_OK);
 	if (!ret) {

src/tests/console.c

@@ -146,6 +146,7 @@ static int test_console(const char *lxcpath,
 	}
 	c->load_config(c, NULL);
 	c->set_config_item(c, "lxc.tty.max", TTYCNT_STR);
+	c->set_config_item(c, "lxc.pty.max", "1024");
 	c->save_config(c, NULL);
 	c->want_daemonize(c, true);
 	if (!c->startl(c, 0, NULL)) {