src/user.c

   1 /*
   2  * This file is part of uxlaunch
   3  *
   4  * (C) Copyright 2009 Intel Corporation
   5  * Authors:
   6  *     Auke Kok <auke@linux.intel.com>
   7  *     Arjan van de Ven <arjan@linux.intel.com>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; version 2
  12  * of the License.
  13  */
  14
  15 #define _GNU_SOURCE
  16 #include <sys/types.h>
  17 #include <unistd.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include <dirent.h>
  22 #include <sys/types.h>
  23 #include <pwd.h>
  24 #include <grp.h>
  25 #include <sys/stat.h>
  26 #include <sys/types.h>
  27
  28
  29 #include "uxlaunch.h"
  30
  31 #include <X11/Xauth.h>
  32
  33 int uid;
  34 struct passwd *pass;
  35
  36 char user_xauth_path[PATH_MAX];
  37
  38 static void do_env(void)
  39 {
  40         char buf[PATH_MAX];
  41         FILE *file;
  42
  43         d_in();
  44
  45         /* start with a clean environ */
  46         clearenv();
  47
  48         setenv("USER", pass->pw_name, 1);
  49         setenv("LOGNAME", pass->pw_name, 1);
  50         setenv("HOME", pass->pw_dir, 1);
  51         setenv("SHELL", pass->pw_shell, 1);
  52         snprintf(buf, PATH_MAX, "/var/spool/mail/%s", pass->pw_name);
  53         setenv("MAIL", buf, 1);
  54         setenv("DISPLAY", displayname, 1);
  55         snprintf(buf, PATH_MAX, "/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:%s/bin", pass->pw_dir);
  56         setenv("PATH", buf, 1);
  57         snprintf(user_xauth_path, PATH_MAX, "%s/.Xauthority", pass->pw_dir);
  58         setenv("XAUTHORITY", user_xauth_path, 1);
  59
  60         file = popen("/bin/bash -l -c export", "r");
  61         if (!file)
  62                 return;
  63
  64         while (!feof(file)) {
  65                 char *c;
  66                 memset(buf, 0, sizeof(buf));
  67                 if (fgets(buf, sizeof(buf) - 1, file) == NULL)
  68                                 break;
  69                 c = strchr(buf, '\n');
  70
  71                 if (strlen(buf) < 12)
  72                         continue;
  73                 if (c)
  74                         *c = 0;
  75
  76                 if (strstr(buf, "PWD"))
  77                         continue;
  78 //              if (strstr(buf, "DISPLAY"))
  79 //                      continue;
  80
  81                 c = strchr(buf, '=');
  82                 if (c) {
  83                         char *c2;
  84                         *c = 0;
  85                         c++;
  86                         if (*c == '"') c++;
  87                         c2 = strchr(c, '"');
  88                         if (c2)
  89                                 *c2 = 0;
  90                         dprintf("Setting %s to %s\n", &buf[11], c);
  91                         setenv(&buf[11], c, 1);
  92                 }
  93
  94         }
  95
  96         pclose(file);
  97         d_out();
  98 }
  99
 100 #define BACKLIGHT_CLASS "/sys/class/backlight"
 101 #define BACKLIGHT_FILE "brightness"
 102
 103 static void set_backlight_driver_perms(const char *backlight_dir_path)
 104 {
 105         char backlight_file_path[PATH_MAX];
 106         int ret;
 107
 108         d_in();
 109
 110         snprintf(backlight_file_path, sizeof(backlight_file_path),
 111                  "%s/%s", backlight_dir_path, BACKLIGHT_FILE);
 112
 113         ret = chown(backlight_dir_path, pass->pw_uid, pass->pw_gid);
 114         if (ret)
 115                 lprintf("Failed to set \"%s\" ownership", backlight_dir_path);
 116
 117         ret = chown(backlight_file_path, pass->pw_uid, pass->pw_gid);
 118         if (ret)
 119                 lprintf("Failed to set \"%s\" ownership", backlight_file_path);
 120
 121         d_out();
 122 }
 123
 124 static void set_backlight_perms(const char *backlight_class)
 125 {
 126         DIR *dir;
 127         struct dirent *entry;
 128         char backlight_dir_path[PATH_MAX];
 129
 130         d_in();
 131
 132         dir = opendir(backlight_class);
 133         if (dir) {
 134                 while (NULL != (entry = readdir (dir))) {
 135                         if (entry->d_name && entry->d_name[0] != '.' &&
 136                             entry->d_type == DT_LNK) {
 137
 138                                 snprintf(backlight_dir_path,
 139                                          sizeof (backlight_dir_path),
 140                                          "%s/%s", backlight_class,
 141                                           entry->d_name);
 142                                 set_backlight_driver_perms(backlight_dir_path);
 143                         }
 144                 }
 145                 closedir (dir);
 146         } else {
 147                 lprintf ("Failed to opendir(\"%s\")", backlight_class);
 148         }
 149
 150         d_out();
 151 }
 152
 153 /*
 154  * Change from root (as we started) to the target user.
 155  * Steps
 156  * 1) setuid/getgid
 157  * 2) env variables: HOME, MAIL, LOGNAME, USER, SHELL, DISPLAY and PATH
 158  * 3) chdir(/home/foo);
 159  */
 160 void switch_to_user(void)
 161 {
 162         FILE *fp;
 163         char fn[PATH_MAX];
 164         int ret;
 165
 166         d_in();
 167
 168         initgroups(pass->pw_name, pass->pw_gid);
 169
 170         /* make sure that the user owns /dev/ttyX */
 171         ret = chown(displaydev, pass->pw_uid, pass->pw_gid);
 172         if (ret)
 173                 lprintf("Failed to fix /dev/tty permission");
 174
 175         /* make sure the user owns the X backlight devices */
 176         set_backlight_perms (BACKLIGHT_CLASS);
 177
 178         if (!((setgid(pass->pw_gid) == 0) && (setuid(pass->pw_uid) == 0))) {
 179                 lprintf("Fatal: Unable to setgid()/setuid()\n");
 180                 exit(EXIT_FAILURE);
 181         }
 182
 183         if (access(pass->pw_dir, R_OK || W_OK || X_OK) != 0) {
 184                 lprintf("Fatal: \"%s\" has incompatible permissions", pass->pw_dir);
 185                 exit(EXIT_FAILURE);
 186         }
 187
 188         if (setpgid(0, getpgid(getppid())) == -1)
 189                 lprintf("Unable to setpgid()");
 190         if (setsid() == -1)
 191                 lprintf("Unable to setsid()");
 192
 193         do_env();
 194
 195         set_i18n();
 196
 197         ret = chdir(pass->pw_dir);
 198
 199         fp = fopen(user_xauth_path, "w");
 200         if (fp) {
 201                 if (XauWriteAuth(fp, &x_auth) != 1)
 202                         lprintf("Unable to write .Xauthority");
 203                 fclose(fp);
 204         }
 205
 206         /* redirect further IO to .xsession-errors */
 207         snprintf(fn, PATH_MAX, "%s/.xsession-errors", pass->pw_dir);
 208         fp = fopen(fn, "w");
 209         if (fp) {
 210                 fclose(fp);
 211                 /* xserver.c already truncates this file, so append */
 212                 fp = freopen(fn, "a", stdout);
 213                 fp = freopen(fn, "a", stderr);
 214         } else {
 215                 lprintf("Unable to open \"%s\n\" for writing", fn);
 216         }
 217
 218         d_out();
 219 }
 220
 221 static char *scim_languages[] = { "zh_", "ja_", "ko_", "lo_", "th_" };
 222
 223 void setup_user_environment (void)
 224 {
 225         unsigned int i;
 226         char buf[PATH_MAX];
 227         const char *lang = getenv ("LANG");
 228
 229         d_in();
 230
 231         for (i = 0; lang && i < sizeof(scim_languages) / sizeof(scim_languages[0]); i++) {
 232                 if (strstr(lang, scim_languages[i])) {
 233                         setenv("GTK_IM_MODULE", "scim-bridge", 0);
 234                         setenv("CLUTTER_IM_MODULE","scim-bridge", 0);
 235                 }
 236         }
 237
 238         /* setup misc. user directories and variables */
 239         snprintf(buf, PATH_MAX, "%s/.cache", pass->pw_dir);
 240         mkdir(buf, 0700);
 241         setenv("XDG_CACHE_HOME", buf, 0);
 242         snprintf(buf, PATH_MAX, "%s/.config", pass->pw_dir);
 243         setenv("XDG_CONFIG_HOME", buf, 0);
 244         setenv("OOO_FORCE_DESKTOP","gnome", 0);
 245         setenv("LIBC_FATAL_STDERR_", "1", 0);
 246
 247         d_out();
 248 }
 249
 250 void set_i18n(void)
 251 {
 252         FILE *f;
 253         char path[PATH_MAX];
 254         char buf[256];
 255         char *key;
 256         char *val;
 257
 258         d_in();
 259
 260         /*
 261          * /etc/sysconfig/i18n contains shell code that sets
 262          * various i18n options in environment, typically:
 263          * LANG, SYSFONT
 264          */
 265         snprintf(path, PATH_MAX, "%s/.config/i18n", pass->pw_dir);
 266         f = fopen(path, "r");
 267         if (f)
 268                 goto parse;
 269         dprintf("Unable to open ~/.config/i18n, trying /etc/sysconfig/i18n");
 270         f = fopen("/etc/sysconfig/i18n", "r");
 271         if (f)
 272                 goto parse;
 273         d_out();
 274         return;
 275
 276 parse:
 277         while (fgets(buf, 256, f) != NULL) {
 278                 char *c;
 279
 280                 c = strchr(buf, '\n');
 281                 if (c) *c = 0; /* remove trailing \n */
 282                 if (buf[0] == '#')
 283                         continue; /* skip comments */
 284
 285                 key = strtok(buf, "=");
 286                 if (!key)
 287                         continue;
 288                 val = strtok(NULL, "=\""); /* note \" */
 289                 if (!val)
 290                         continue;
 291
 292                 /* grab the stuff we need, avoiding comments
 293                  * and other user stuff we don't care for now */
 294                 if (!strcmp(key, "LANG"))
 295                         setenv(key, val, 1);
 296                 if (!strcmp(key, "SYSFONT"))
 297                         setenv(key, val, 1);
 298         }
 299         fclose(f);
 300
 301         d_out();
 302 }