source/modules/vfs_expand_msdfs.c

   1 /*
   2  * Expand msdfs targets based on client IP
   3  *
   4  * Copyright (C) Volker Lendecke, 2004
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include "includes.h"
  22
  23 #undef DBGC_CLASS
  24 #define DBGC_CLASS DBGC_VFS
  25
  26 extern userdom_struct current_user_info;
  27
  28 /**********************************************************
  29   Under mapfile we expect a table of the following format:
  30
  31   IP-Prefix whitespace expansion
  32
  33   For example:
  34   192.168.234 local.samba.org
  35   192.168     remote.samba.org
  36               default.samba.org
  37
  38   This is to redirect a DFS client to a host close to it.
  39 ***********************************************************/
  40
  41 static BOOL read_target_host(const char *mapfile, pstring targethost)
  42 {
  43         XFILE *f;
  44         pstring buf;
  45         char *space = buf;
  46         BOOL found = False;
  47
  48         f = x_fopen(mapfile, O_RDONLY, 0);
  49
  50         if (f == NULL) {
  51                 DEBUG(0,("can't open IP map %s. Error %s\n",
  52                          mapfile, strerror(errno) ));
  53                 return False;
  54         }
  55
  56         DEBUG(10, ("Scanning mapfile [%s]\n", mapfile));
  57
  58         while (x_fgets(buf, sizeof(buf), f) != NULL) {
  59
  60                 if ((strlen(buf) > 0) && (buf[strlen(buf)-1] == '\n'))
  61                         buf[strlen(buf)-1] = '\0';
  62
  63                 DEBUG(10, ("Scanning line [%s]\n", buf));
  64
  65                 space = strchr_m(buf, ' ');
  66
  67                 if (space == NULL) {
  68                         DEBUG(0, ("Ignoring invalid line %s\n", buf));
  69                         continue;
  70                 }
  71
  72                 *space = '\0';
  73
  74                 if (strncmp(client_addr(), buf, strlen(buf)) == 0) {
  75                         found = True;
  76                         break;
  77                 }
  78         }
  79
  80         x_fclose(f);
  81
  82         if (!found)
  83                 return False;
  84
  85         space += 1;
  86
  87         while (isspace(*space))
  88                 space += 1;
  89
  90         pstrcpy(targethost, space);
  91         return True;
  92 }
  93
  94 /**********************************************************
  95
  96   Expand the msdfs target host using read_target_host
  97   explained above. The syntax used in the msdfs link is
  98
  99   msdfs:@table-filename@/share
 100
 101   Everything between and including the two @-signs is
 102   replaced by the substitution string found in the table
 103   described above.
 104
 105 ***********************************************************/
 106
 107 static BOOL expand_msdfs_target(connection_struct* conn, pstring target)
 108 {
 109         pstring mapfilename;
 110         char *filename_start = strchr_m(target, '@');
 111         char *filename_end;
 112         int filename_len;
 113         pstring targethost;
 114         pstring new_target;
 115
 116         if (filename_start == NULL) {
 117                 DEBUG(10, ("No filename start in %s\n", target));
 118                 return False;
 119         }
 120
 121         filename_end = strchr_m(filename_start+1, '@');
 122
 123         if (filename_end == NULL) {
 124                 DEBUG(10, ("No filename end in %s\n", target));
 125                 return False;
 126         }
 127
 128         filename_len = PTR_DIFF(filename_end, filename_start+1);
 129         pstrcpy(mapfilename, filename_start+1);
 130         mapfilename[filename_len] = '\0';
 131
 132         DEBUG(10, ("Expanding from table [%s]\n", mapfilename));
 133
 134         if (!read_target_host(mapfilename, targethost)) {
 135                 DEBUG(1, ("Could not expand target host from file %s\n",
 136                           mapfilename));
 137                 return False;
 138         }
 139
 140         standard_sub_advanced(lp_servicename(SNUM(conn)), conn->user,
 141                               conn->connectpath, conn->gid,
 142                               get_current_username(),
 143                               current_user_info.domain,
 144                               mapfilename, sizeof(mapfilename));
 145
 146         DEBUG(10, ("Expanded targethost to %s\n", targethost));
 147
 148         *filename_start = '\0';
 149         pstrcpy(new_target, target);
 150         pstrcat(new_target, targethost);
 151         pstrcat(new_target, filename_end+1);
 152
 153         DEBUG(10, ("New DFS target: %s\n", new_target));
 154         pstrcpy(target, new_target);
 155         return True;
 156 }
 157
 158 static int expand_msdfs_readlink(struct vfs_handle_struct *handle,
 159                                  const char *path, char *buf, size_t bufsiz)
 160 {
 161         pstring target;
 162         int result;
 163
 164         result = SMB_VFS_NEXT_READLINK(handle, path, target,
 165                                        sizeof(target));
 166
 167         if (result < 0)
 168                 return result;
 169
 170         target[result] = '\0';
 171
 172         if ((strncmp(target, "msdfs:", strlen("msdfs:")) == 0) &&
 173             (strchr_m(target, '@') != NULL)) {
 174                 if (!expand_msdfs_target(handle->conn, target)) {
 175                         errno = ENOENT;
 176                         return -1;
 177                 }
 178         }
 179
 180         safe_strcpy(buf, target, bufsiz-1);
 181         return strlen(buf);
 182 }
 183
 184 /* VFS operations structure */
 185
 186 static vfs_op_tuple expand_msdfs_ops[] = {
 187         {SMB_VFS_OP(expand_msdfs_readlink), SMB_VFS_OP_READLINK,
 188          SMB_VFS_LAYER_TRANSPARENT},
 189         {SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
 190 };
 191
 192 NTSTATUS vfs_expand_msdfs_init(void);
 193 NTSTATUS vfs_expand_msdfs_init(void)
 194 {
 195         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "expand_msdfs",
 196                                 expand_msdfs_ops);
 197 }