openrc-user binary

init.d/meson.build

@@ -16,6 +16,7 @@ init_common =  [
   'sysctl.in',
   'runsvdir.in',
   's6-svscan.in',
+  'users.in',
   ]
 
 if get_option('newnet')

init.d/users.in

@@ -0,0 +1,32 @@
+#!@SBINDIR@/openrc-run
+# Copyright (c) 2017 The OpenRC Authors.
+# See the Authors file at the top-level directory of this distribution and
+# https://github.com/OpenRC/openrc/blob/HEAD/AUTHORS
+#
+# This file is part of OpenRC. It is subject to the license terms in
+# the LICENSE file found in the top-level directory of this
+# distribution and at https://github.com/OpenRC/openrc/blob/HEAD/LICENSE
+# This file may not be copied, modified, propagated, or distributed
+# except according to the terms contained in the LICENSE file.
+
+description="Starts and stops openrc --user for system users."
+
+start() {
+	mkdir "$RC_SVCDIR"/users || return 1
+	for user in ${rc_users}; do
+		ebegin "Starting user session for $user"
+		openrc-user $user start
+		echo "-1" > "@SYSCONFDIR@/users/$user"
+		eend $?
+	done
+	return 0
+}
+
+stop() {
+	for user in "$RC_SVCDIR"/users/*; do
+		ebegin "Stopping user session for $user"
+		openrc-user $user stop
+		eend $?
+	done
+	return 0
+}

sh/meson.build

@@ -23,6 +23,7 @@ sh_config = [
 scripts_config = [
   'gendepends.sh.in',
   'openrc-run.sh.in',
+  'openrc-user.sh.in',
   ]
 
 if os == 'Linux'

sh/openrc-user.sh.in

@@ -0,0 +1,22 @@
+#!@SHELL@
+
+. @LIBEXECDIR@/sh/functions.sh
+
+_sysconf="${XDG_CONFIG_HOME:-${HOME}/.config}/openrc"
+
+for config in "@SYSCONFDIR@/rc.conf" "$_sysconf/rc.conf"; do
+	if [ -e "$config" ] && ! . "$config"; then
+		eerror "openrc-user: Failed loading $config"
+		exit 1
+	fi
+done
+
+case $1 in
+	start) _runlevel="${rc_user_runlevel:-default}";;
+	stop) _runlevel="${rc_user_shutdown_runlevel:-none}";;
+	*) eerror "no argument given to $0" && exit 1
+esac
+
+mkdir -p "$_sysconf/runlevels/$_runlevel"
+
+openrc --user "$_runlevel"

src/meson.build

@@ -18,6 +18,7 @@ subdir('openrc')
 subdir('openrc-init')
 subdir('openrc-run')
 subdir('openrc-shutdown')
+subdir('openrc-user')
 subdir('poweroff')
 subdir('rc-abort')
 subdir('rc-depend')

src/openrc-user/meson.build

@@ -0,0 +1,7 @@
+executable('openrc-user', ['openrc-user.c'],
+  c_args: [cc_pam_flags],
+  dependencies: pam_dep,
+  include_directories: [incdir, einfo_incdir, rc_incdir],
+  link_with: [libeinfo, librc],
+  install: true,
+  install_dir: rc_bindir)

src/openrc-user/openrc-user.c

@@ -0,0 +1,233 @@
+#include <einfo.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <syslog.h>
+#include <unistd.h>
+#include <signal.h>
+
+#ifdef HAVE_PAM
+#include <security/pam_appl.h>
+
+static int
+openrc_conv(int num_msg, const struct pam_message **msgm, struct pam_response **response, void *appdata_ptr)
+{
+	(void) response;
+	(void) appdata_ptr;
+
+	for (int i = 0; i < num_msg; i++) {
+		switch (msgm[i]->msg_style) {
+		case PAM_ERROR_MSG:
+		case PAM_TEXT_INFO:
+			if (msgm[i]->msg != NULL)
+				elog(LOG_ERR, "pam_message: %s", msgm[i]->msg);
+			break;
+		default:
+			break;
+		}
+	}
+	return 0;
+}
+
+static struct pam_conv conv = { openrc_conv, NULL };
+#endif
+
+#include "helpers.h"
+#include "rc.h"
+
+const struct passwd *user;
+char *pidfile;
+
+static bool do_setup(const char *username) {
+	char *logname;
+	int nullfd;
+
+	xasprintf(&logname, "openrc-user[%s]", username);
+	setenv("EINFO_LOG", logname, true);
+	free(logname);
+
+	if (!(user = getpwnam(username))) {
+		elog(LOG_ERR, "getpwnam failed: %s", strerror(errno));
+		return false;
+	}
+
+	nullfd = open("/dev/null", O_RDWR);
+	dup2(nullfd, STDIN_FILENO);
+	close(nullfd);
+
+	return true;
+}
+
+static bool check_pidfile(bool start) {
+	struct stat buf;
+	FILE *file;
+
+	xasprintf(&pidfile, "%s/users/%s", rc_svcdir(), user->pw_name);
+	stat(pidfile, &buf);
+	if (stat(pidfile, &buf) == 0 && buf.st_size > 0 && (file = fopen(pidfile, "r"))) {
+		pid_t pid = 0;
+		if (fscanf(file, "%d", &pid) != 1 || kill(pid, start ? SIGUSR1 : SIGUSR2) == -1) {
+			elog(LOG_ERR, "Failed to signal pid %d, resetting.", pid);
+			exit(1);
+		}
+		return true;
+	}
+
+	if (!(file = fopen(pidfile, "w"))) {
+		elog(LOG_ERR, "Failed to open pidfile %s: %s", pidfile, strerror(errno));
+		exit(1);
+	}
+
+	fprintf(file, "%d\n", getpid());
+	fclose(file);
+
+	return false;
+}
+
+static void do_openrc(bool start) {
+	pid_t child;
+	char *cmd;
+
+	switch ((child = fork())) {
+	case 0:
+		if (setgid(user->pw_gid) == -1 || setuid(user->pw_uid) == -1) {
+			elog(LOG_ERR, "Failed to drop permissions to user.");
+			exit(1);
+		}
+
+		setenv("HOME", user->pw_dir, true);
+		setenv("SHELL", user->pw_shell, true);
+
+		xasprintf(&cmd, "%s %s", RC_LIBEXECDIR "/sh/openrc-user.sh", start ? "start" : "stop");
+		execl(user->pw_shell, "-", "-c", cmd, NULL);
+
+		elog(LOG_ERR, "Failed to execl '%s - -c %s': %s.", user->pw_shell, cmd, strerror(errno));
+		exit(1);
+	case -1:
+		exit(1);
+	default:
+		break;
+	}
+
+	waitpid(child, NULL, 0);
+}
+
+static void do_wait(void) {
+	size_t logins = 1;
+	sigset_t set;
+	int sig;
+
+	sigemptyset(&set);
+	sigaddset(&set, SIGUSR1);
+	sigaddset(&set, SIGUSR2);
+	sigaddset(&set, SIGTERM);
+
+	sigprocmask(SIG_SETMASK, &set, NULL);
+
+	while (logins > 0) {
+		sigwait(&set, &sig);
+		switch (sig) {
+		case SIGUSR1:
+			logins++;
+			break;
+		case SIGUSR2:
+			logins--;
+			break;
+		case SIGTERM:
+		case SIGKILL:
+			return;
+		default:
+			break;
+		}
+	}
+
+	return;
+}
+
+#ifdef HAVE_PAM
+static pam_handle_t *open_session(void) {
+	pam_handle_t *pamh = NULL;
+	bool pam_session = false;
+	int rc;
+
+	if ((rc = pam_start("openrc-user", user->pw_name, &conv, &pamh)) != PAM_SUCCESS)
+		elog(LOG_ERR, "Failed to start pam: %s", pam_strerror(pamh, rc));
+	else if ((rc = pam_open_session(pamh, PAM_SILENT)) != PAM_SUCCESS)
+		elog(LOG_ERR, "Failed to open session: %s", pam_strerror(pamh, rc));
+	else
+		pam_session = true;
+
+	for (char **env = pam_getenvlist(pamh); env && *env; env++) {
+		if (strchr(*env, '='))
+			putenv(xstrdup(*env));
+		else
+			unsetenv(*env);
+	}
+
+	if (!pam_session && pamh) {
+		pam_end(pamh, rc);
+		return NULL;
+	}
+
+	return pamh;
+}
+#endif
+
+int main(int argc, char **argv) {
+	bool start;
+
+#ifdef HAVE_PAM
+	pam_handle_t *pamh = NULL;
+#endif
+
+	if (argc < 3) {
+		fprintf(stderr, "%s: Not enough arguments.\n", argv[0]);
+		return 1;
+	}
+
+	if (strcmp(argv[2], "start") == 0) {
+		start = true;
+	} else if (strcmp(argv[2], "stop") == 0) {
+		start = false;
+	} else {
+		fprintf(stderr, "%s: Invalid argument %s.\n", argv[0], argv[2]);
+		return 1;
+	}
+
+	if (!do_setup(argv[1]))
+		return 1;
+
+	if (check_pidfile(start))
+		return 0;
+
+	/* we need to initgroups before pam is setup. */
+	if (initgroups(user->pw_name, user->pw_gid) == -1)
+		return 1;
+
+#ifdef HAVE_PAM
+	pamh = open_session();
+#endif
+
+	do_openrc(true);
+	do_wait();
+	do_openrc(false);
+
+#ifdef HAVE_PAM
+	if (pamh) {
+		int rc;
+		if ((rc = pam_close_session(pamh, PAM_SILENT)) != PAM_SUCCESS)
+			elog(LOG_ERR, "Failed to close session: %s", pam_strerror(pamh, rc));
+		if ((rc = pam_setcred(pamh, PAM_DELETE_CRED)) != PAM_SUCCESS)
+			elog(LOG_ERR, "Failed to delete user's credentials: %s", pam_strerror(pamh, rc));
+		pam_end(pamh, rc);
+	}
+#endif
+
+	unlink(pidfile);
+	free(pidfile);
+	return 0;
+}