From b98b9dbda902225cdd972b5bff6a641c36cc7e90 Mon Sep 17 00:00:00 2001
From: Tom Hochstein <tom.hochstein@nxp.com>
Date: Wed, 22 Feb 2017 15:53:30 +0200
Subject: [PATCH] weston-launch: Provide a default version that doesn't require PAM

weston-launch requires PAM for starting weston as a non-root user.

Since starting weston as root is a valid use case by itself, if
PAM is not available, provide a default version of weston-launch
without non-root-user support.

Upstream-Status: Pending

Signed-off-by: Tom Hochstein <tom.hochstein@nxp.com>
Signed-off-by: Jussi Kukkonen <jussi.kukkonen@intel.com>
Signed-off-by: Denys Dmytriyenko <denys@ti.com>

---
 configure.ac              |  9 +++++++--
 libweston/weston-launch.c | 20 ++++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index dc9c802..48cf5cb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -451,13 +451,17 @@ AC_ARG_ENABLE(resize-optimization,
 AS_IF([test "x$enable_resize_optimization" = "xyes"],
       [AC_DEFINE([USE_RESIZE_POOL], [1], [Use resize memory pool as a performance optimization])])
 
+AC_ARG_WITH(pam,
+            AS_HELP_STRING([--with-pam], [Use PAM]),
+            [use_pam=$withval], [use_pam=yes])
 AC_ARG_ENABLE(weston-launch, [  --enable-weston-launch],, enable_weston_launch=yes)
 AM_CONDITIONAL(BUILD_WESTON_LAUNCH, test x$enable_weston_launch = xyes)
-if test x$enable_weston_launch = xyes; then
+if test x$enable_weston_launch = xyes -a x$use_pam = xyes; then
   WESTON_SEARCH_LIBS([PAM], [pam], [pam_open_session], [have_pam=yes], [have_pam=no])
   if test x$have_pam = xno; then
-    AC_ERROR([weston-launch requires pam])
+    AC_ERROR([PAM support is explicitly requested, but libpam couldn't be found])
   fi
+  AC_DEFINE([HAVE_PAM], [1], [Define if PAM is available])
 fi
 
 AM_CONDITIONAL(HAVE_PANGO, test "x$have_pango" = "xyes")
@@ -702,6 +706,7 @@ AC_MSG_RESULT([
 	Enable developer documentation	${enable_devdocs}
 
 	weston-launch utility		${enable_weston_launch}
+	PAM support			${use_pam}
 	systemd-login support		${have_systemd_login}
 	systemd notify support		${enable_systemd_notify}
 
diff --git a/libweston/weston-launch.c b/libweston/weston-launch.c
index 166bf3b..6fb9232 100644
--- a/libweston/weston-launch.c
+++ b/libweston/weston-launch.c
@@ -51,7 +51,9 @@
 
 #include <pwd.h>
 #include <grp.h>
+#ifdef HAVE_PAM
 #include <security/pam_appl.h>
+#endif
 
 #ifdef HAVE_SYSTEMD_LOGIN
 #include <systemd/sd-login.h>
@@ -101,8 +103,10 @@ drmSetMaster(int drm_fd)
 #endif
 
 struct weston_launch {
+#ifdef HAVE_PAM
 	struct pam_conv pc;
 	pam_handle_t *ph;
+#endif
 	int tty;
 	int ttynr;
 	int sock[2];
@@ -189,6 +193,7 @@ weston_launch_allowed(struct weston_launch *wl)
 	return false;
 }
 
+#ifdef HAVE_PAM
 static int
 pam_conversation_fn(int msg_count,
 		    const struct pam_message **messages,
@@ -229,6 +234,7 @@ setup_pam(struct weston_launch *wl)
 
 	return 0;
 }
+#endif
 
 static int
 setup_launcher_socket(struct weston_launch *wl)
@@ -422,6 +428,7 @@ quit(struct weston_launch *wl, int status)
 	close(wl->signalfd);
 	close(wl->sock[0]);
 
+#ifdef HAVE_PAM
 	if (wl->new_user) {
 		err = pam_close_session(wl->ph, 0);
 		if (err)
@@ -429,6 +436,7 @@ quit(struct weston_launch *wl, int status)
 				err, pam_strerror(wl->ph, err));
 		pam_end(wl->ph, err);
 	}
+#endif
 
 	if (ioctl(wl->tty, KDSKBMUTE, 0) &&
 	    ioctl(wl->tty, KDSKBMODE, wl->kb_mode))
@@ -608,6 +616,7 @@ setup_session(struct weston_launch *wl, char **child_argv)
 	setenv("HOME", wl->pw->pw_dir, 1);
 	setenv("SHELL", wl->pw->pw_shell, 1);
 
+#ifdef HAVE_PAM
 	env = pam_getenvlist(wl->ph);
 	if (env) {
 		for (i = 0; env[i]; ++i) {
@@ -616,6 +625,7 @@ setup_session(struct weston_launch *wl, char **child_argv)
 		}
 		free(env);
 	}
+#endif
 
 	/*
 	 * We open a new session, so it makes sense
@@ -683,8 +693,10 @@ static void
 help(const char *name)
 {
 	fprintf(stderr, "Usage: %s [args...] [-- [weston args..]]\n", name);
+#ifdef HAVE_PAM
 	fprintf(stderr, "  -u, --user      Start session as specified username,\n"
 			"                  e.g. -u joe, requires root.\n");
+#endif
 	fprintf(stderr, "  -t, --tty       Start session on alternative tty,\n"
 			"                  e.g. -t /dev/tty4, requires -u option.\n");
 	fprintf(stderr, "  -v, --verbose   Be verbose\n");
@@ -698,7 +710,9 @@ main(int argc, char *argv[])
 	int i, c;
 	char *tty = NULL;
 	struct option opts[] = {
+#ifdef HAVE_PAM
 		{ "user",    required_argument, NULL, 'u' },
+#endif
 		{ "tty",     required_argument, NULL, 't' },
 		{ "verbose", no_argument,       NULL, 'v' },
 		{ "help",    no_argument,       NULL, 'h' },
@@ -710,9 +724,13 @@ main(int argc, char *argv[])
 	while ((c = getopt_long(argc, argv, "u:t:vh", opts, &i)) != -1) {
 		switch (c) {
 		case 'u':
+#ifdef HAVE_PAM
 			wl.new_user = optarg;
 			if (getuid() != 0)
 				error(1, 0, "Permission denied. -u allowed for root only");
+#else
+			error(1, 0, "-u is unsupported in this weston-launch build");
+#endif
 			break;
 		case 't':
 			tty = optarg;
@@ -753,8 +771,10 @@ main(int argc, char *argv[])
 	if (setup_tty(&wl, tty) < 0)
 		exit(EXIT_FAILURE);
 
+#ifdef HAVE_PAM
 	if (wl.new_user && setup_pam(&wl) < 0)
 		exit(EXIT_FAILURE);
+#endif
 
 	if (setup_launcher_socket(&wl) < 0)
 		exit(EXIT_FAILURE);