conffile.c

   1 /* usmb - mount SMB shares via FUSE and Samba
   2  * Copyright (C) 2006-2010 Geoff Johnstone
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 3 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include "config.h"
  18 #include <assert.h>
  19 #include <errno.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <unistd.h>
  27 #include "utils.h"
  28 #include "xml.h"
  29 #include "conffile.h"
  30 #include "config.rng.h"
  31
  32
  33 static bool check_conf_perms (const char *conffile, int fd)
  34 {
  35   struct stat buf;
  36
  37   if (0 == fstat (fd, &buf))
  38   {
  39     if (getuid() != buf.st_uid)
  40     {
  41       fprintf (stderr, "You do not own the configuration file %s.\n", conffile);
  42       return false;
  43     }
  44
  45     if (buf.st_mode & (S_IRWXG | S_IRWXO))
  46     {
  47       fprintf (stderr, "Configuration file %s is accessible to non-owner.\n",
  48                conffile);
  49       return false;
  50     }
  51   }
  52
  53   else
  54   {
  55     fprintf (stderr, "Cannot stat configuration file %s: %s.\n",
  56              conffile, strerror (errno));
  57     return false;
  58   }
  59
  60   return true;
  61 }
  62
  63
  64 static bool conffile_read (const char *filename,
  65                            xmlDocPtr *doc,
  66                            xmlXPathContextPtr *ctx)
  67 {
  68   int fd = open (filename, O_RDONLY);
  69   if (-1 == fd)
  70   {
  71     fprintf (stderr, "Cannot open %s: %s.\n", filename, strerror (errno));
  72     return false;
  73   }
  74
  75   if (!check_conf_perms (filename, fd))
  76   {
  77     (void)close (fd);
  78     return false;
  79   }
  80
  81   *doc = xmlReadFd (fd, NULL, NULL, XML_PARSE_NONET);
  82   (void)close (fd);
  83
  84   if (NULL == *doc)
  85   {
  86     fprintf (stderr, "Cannot parse %s.\n", filename);
  87     return false;
  88   }
  89
  90   if (!xml_validate_relaxng (*doc, rng_config))
  91   {
  92     fprintf (stderr, "%s isn't a valid USMB configuration.\n", filename);
  93     xmlFreeDoc (*doc);
  94     return false;
  95   }
  96
  97   *ctx = xmlXPathNewContext (*doc);
  98   if (NULL == *ctx)
  99   {
 100     fputs ("Cannot create XPath context.\n", stderr);
 101     xmlFreeDoc (*doc);
 102     return false;
 103   }
 104
 105   return true;
 106 }
 107
 108
 109 static bool do_xpath_text (xmlXPathContextPtr ctx,
 110                            const char *parent, const char *id,
 111                            const char *child, char **out)
 112 {
 113   char xpath[2048];
 114   snprintf (xpath, sizeof (xpath),
 115             "/usmbconfig/%s[@id='%s']/%s/text()", parent, id, child);
 116   return xml_xpath_text (ctx, xpath, (void *)out);
 117 }
 118
 119
 120 bool conffile_get_mount (const char *filename, const char *key,
 121                          char **server, char **share,
 122                          char **mountpoint, char **options,
 123                          char **domain, char **username,
 124                          char **password)
 125 {
 126   xmlDocPtr doc;
 127   xmlXPathContextPtr ctx;
 128   char xp[2048];
 129   char *creds = NULL;
 130
 131   *server = *share = *mountpoint = *options = NULL;
 132   *domain = *username = *password = NULL;
 133
 134   if (strchr (key, '\''))
 135   {
 136     fprintf (stderr, "Invalid share name: %s.\n", key);
 137     return false;
 138   }
 139
 140   if (!conffile_read (filename, &doc, &ctx))
 141     return false;
 142
 143   do {
 144     if (!do_xpath_text (ctx, "mount", key, "server", server)) break;
 145     if (!do_xpath_text (ctx, "mount", key, "share", share)) break;
 146     if (!do_xpath_text (ctx, "mount", key, "mountpoint", mountpoint)) break;
 147     (void)do_xpath_text (ctx, "mount", key, "options", options);
 148
 149     snprintf (xp, sizeof (xp), "/usmbconfig/mount[@id='%s']", key);
 150     if (!xml_xpath_attr_value (ctx, xp, "credentials", &creds)) break;
 151
 152     (void)do_xpath_text (ctx, "credentials", creds, "domain", domain);
 153     if (!do_xpath_text (ctx, "credentials", creds, "username", username)) break;
 154
 155     if (!do_xpath_text (ctx, "credentials", creds, "password", password))
 156       *password = NULL;
 157
 158     xmlXPathFreeContext (ctx);
 159     xmlFreeDoc (doc);
 160
 161     return true;
 162     /*NOTREACHED*/
 163   } while (false /*CONSTCOND*/);
 164
 165   fputs ("Invalid configuration.\n", stderr);
 166
 167   xfree (*username);
 168   clear_and_free (*password);
 169   xfree (*domain);
 170   xfree (creds);
 171   xfree (*options);
 172   xfree (*mountpoint);
 173   xfree (*share);
 174   xfree (*server);
 175
 176   xmlXPathFreeContext (ctx);
 177   xmlFreeDoc (doc);
 178
 179   return false;
 180 }
 181