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 /**********************************************************
  27   Under mapfile we expect a table of the following format:
  28
  29   IP-Prefix whitespace expansion
  30
  31   For example:
  32   192.168.234 local.samba.org
  33   192.168     remote.samba.org
  34               default.samba.org
  35
  36   This is to redirect a DFS client to a host close to it.
  37 ***********************************************************/
  38
  39 static BOOL read_target_host(const char *mapfile, pstring targethost)
  40 {
  41         XFILE *f;
  42         pstring buf;
  43         char *space = buf;
  44         BOOL found = False;
  45
  46         f = x_fopen(mapfile, O_RDONLY, 0);
  47
  48         if (f == NULL) {
  49                 DEBUG(0,("can't open IP map %s. Error %s\n",
  50                          mapfile, strerror(errno) ));
  51                 return False;
  52         }
  53
  54         DEBUG(10, ("Scanning mapfile [%s]\n", mapfile));
  55
  56         while (x_fgets(buf, sizeof(buf), f) != NULL) {
  57
  58                 if ((strlen(buf) > 0) && (buf[strlen(buf)-1] == '\n'))
  59                         buf[strlen(buf)-1] = '\0';
  60
  61                 DEBUG(10, ("Scanning line [%s]\n", buf));
  62
  63                 space = strchr_m(buf, ' ');
  64
  65                 if (space == NULL) {
  66                         DEBUG(0, ("Ignoring invalid line %s\n", buf));
  67                         continue;
  68                 }
  69
  70                 *space = '\0';
  71
  72                 if (strncmp(client_addr(), buf, strlen(buf)) == 0) {
  73                         found = True;
  74                         break;
  75                 }
  76         }
  77
  78         x_fclose(f);
  79
  80         if (!found)
  81                 return False;
  82
  83         space += 1;
  84
  85         while (isspace(*space))
  86                 space += 1;
  87
  88         pstrcpy(targethost, space);
  89         return True;
  90 }
  91
  92 /**********************************************************
  93
  94   Expand the msdfs target host using read_target_host
  95   explained above. The syntax used in the msdfs link is
  96
  97   msdfs:@table-filename@/share
  98
  99   Everything between and including the two @-signs is
 100   replaced by the substitution string found in the table
 101   described above.
 102
 103 ***********************************************************/
 104
 105 static BOOL expand_msdfs_target(connection_struct* conn, pstring target)
 106 {
 107         pstring mapfilename;
 108         char *filename_start = strchr_m(target, '@');
 109         char *filename_end;
 110         int filename_len;
 111         pstring targethost;
 112         pstring new_target;
 113
 114         if (filename_start == NULL) {
 115                 DEBUG(10, ("No filename start in %s\n", target));
 116                 return False;
 117         }
 118
 119         filename_end = strchr_m(filename_start+1, '@');
 120
 121         if (filename_end == NULL) {
 122                 DEBUG(10, ("No filename end in %s\n", target));
 123                 return False;
 124         }
 125
 126         filename_len = PTR_DIFF(filename_end, filename_start+1);
 127         pstrcpy(mapfilename, filename_start+1);
 128         mapfilename[filename_len] = '\0';
 129
 130         DEBUG(10, ("Expanding from table [%s]\n", mapfilename));
 131
 132         if (!read_target_host(mapfilename, targethost)) {
 133                 DEBUG(1, ("Could not expand target host from file %s\n",
 134                           mapfilename));
 135                 return False;
 136         }
 137
 138         standard_sub_conn(conn, mapfilename, sizeof(mapfilename));
 139
 140         DEBUG(10, ("Expanded targethost to %s\n", targethost));
 141
 142         *filename_start = '\0';
 143         pstrcpy(new_target, target);
 144         pstrcat(new_target, targethost);
 145         pstrcat(new_target, filename_end+1);
 146
 147         DEBUG(10, ("New DFS target: %s\n", new_target));
 148         pstrcpy(target, new_target);
 149         return True;
 150 }
 151
 152 static int expand_msdfs_readlink(struct vfs_handle_struct *handle,
 153                                  struct connection_struct *conn,
 154                                  const char *path, char *buf, size_t bufsiz)
 155 {
 156         pstring target;
 157         int result;
 158
 159         result = SMB_VFS_NEXT_READLINK(handle, conn, path, target,
 160                                        sizeof(target));
 161
 162         if (result < 0)
 163                 return result;
 164
 165         target[result] = '\0';
 166
 167         if ((strncmp(target, "msdfs:", strlen("msdfs:")) == 0) &&
 168             (strchr_m(target, '@') != NULL)) {
 169                 if (!expand_msdfs_target(conn, target)) {
 170                         errno = ENOENT;
 171                         return -1;
 172                 }
 173         }
 174
 175         safe_strcpy(buf, target, bufsiz-1);
 176         return strlen(buf);
 177 }
 178
 179 /* VFS operations structure */
 180
 181 static vfs_op_tuple expand_msdfs_ops[] = {
 182         {SMB_VFS_OP(expand_msdfs_readlink), SMB_VFS_OP_READLINK,
 183          SMB_VFS_LAYER_TRANSPARENT},
 184         {SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
 185 };
 186
 187 NTSTATUS vfs_expand_msdfs_init(void)
 188 {
 189         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "expand_msdfs",
 190                                 expand_msdfs_ops);
 191 }