user.c

/*
 * This file is part of uxlaunch
 *
 * (C) Copyright 2009 Intel Corporation
 * Authors: 
 *     Auke Kok <auke@linux.intel.com>
 *     Arjan van de Ven <arjan@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2
 * of the License.
 */

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <sys/stat.h>
#include <sys/types.h>


#include "uxlaunch.h"

#include <X11/Xauth.h>

int uid;
struct passwd *pass;

char user_xauth_path[PATH_MAX];


/*
 * Change from root (as we started) to the target user.
 * Steps
 * 1) setuid/getgid
 * 2) env variables: HOME, MAIL, LOGNAME, USER, SHELL, DISPLAY and PATH
 * 3) chdir(/home/foo);
 */
void switch_to_user(void)
{
	char buf[PATH_MAX];
	int result;
	FILE *fp;
	char fn[PATH_MAX];
	int ret;

	lprintf("Entering switch_to_user");

	initgroups(pass->pw_name, pass->pw_gid);

	/* make sure that the user owns /dev/ttyX */
	ret = chown(displaydev, pass->pw_uid, pass->pw_gid);
	if (ret)
		lprintf("Failed to fix /dev/tty permission");

	if (!((setgid(pass->pw_gid) == 0) && (setuid(pass->pw_uid) == 0)))
		exit(EXIT_FAILURE);

	setsid();

	/* start with a clean environ */
	clearenv();

	setenv("USER", pass->pw_name, 1);
	setenv("LOGNAME", pass->pw_name, 1);
	setenv("HOME", pass->pw_dir, 1);
	setenv("SHELL", pass->pw_shell, 1);
	snprintf(buf, PATH_MAX, "/var/spool/mail/%s", pass->pw_name);
	setenv("MAIL", buf, 1);
	setenv("DISPLAY", displayname, 1);
	snprintf(buf, PATH_MAX, "/usr/local/bin:/bin:/usr/bin:%s/bin", pass->pw_dir);
	setenv("PATH", buf, 1);
	snprintf(user_xauth_path, PATH_MAX, "%s/.Xauthority", pass->pw_dir);
	setenv("XAUTHORITY", user_xauth_path, 1);

	set_i18n();

	result = chdir(pass->pw_dir);

	fp = fopen(user_xauth_path, "w");
	if (fp) {
		if (XauWriteAuth(fp, &x_auth) != 1)
			lprintf("Unable to write .Xauthority");
		fclose(fp);
	}

	/* redirect further IO to .xsession-errors */
	snprintf(fn, PATH_MAX, "%s/.xsession-errors", pass->pw_dir);
	fp = fopen(fn, "w");
	if (fp) {
		fclose(fp);
		fp = freopen(fn, "w", stdout);
		fp = freopen(fn, "w", stderr);
	}
}

void set_i18n(void)
{
	FILE *f;
	lprintf("entering set_i18n");


	/*
	 * /etc/sysconfig/i18n contains shell code that sets
	 * various i18n options in environment, typically:
	 * LANG, SYSFONT
	 */

	f = fopen("/etc/sysconfig/i18n", "r");
	if (f) {
		char buf[256];
		char *key;
		char *val;

		while (fgets(buf, 256, f) != NULL) {
			char *c;

			c = strchr(buf, '\n');
			if (c) *c = 0; /* remove trailing \n */
			if (buf[0] == '#')
				continue; /* skip comments */

			key = strtok(buf, "=");
			if (!key)
				continue;
			val = strtok(NULL, "=\""); /* note \" */
			if (!val)
				continue;

			/* grab the stuff we need, avoiding comments
			 * and other user stuff we don't care for now */
			if (!strcmp(key, "LANG")) {
				setenv(key, val, 1);
			}
			if (!strcmp(key, "SYSFONT"))
				setenv(key, val, 1);
		}
		fclose(f);
	}

	log_environment();
}

void setup_user_environment (void)
{
	int i;
	char buf[PATH_MAX];
	const char *lang;
	static const char *scim_langs[] = {
		"zh_", "ko_", "ja_", NULL
	};

	/* launch scim only where it makes sense */
	lang = getenv ("LANG");
	for (i = 0; lang && scim_langs[i]; i++) {
		if (strstr (lang, scim_langs[i])) {
			setenv("GTK_IM_MODULE", "scim-bridge", 0);
			setenv("CLUTTER_IM_MODULE","scim-bridge", 0);
			break;
		}
	}

	/* setup misc. user directories and variables */
	snprintf(buf, PATH_MAX, "%s/.cache", pass->pw_dir);
	mkdir(buf, 0700);
	setenv("XDG_CACHE_HOME", buf, 0);
	snprintf(buf, PATH_MAX, "%s/.config", pass->pw_dir);
	setenv("XDG_CONFIG_HOME", buf, 0);
	setenv("OOO_FORCE_DESKTOP","gnome", 0);
}