change_dir.c

   1 /*
   2  * User FTP Server,  Share folders over FTP without being root.
   3  * Copyright (C) 2008  Isaac Jurado
   4  *
   5  * This program is free software; you can redistribute it and/or modify it under
   6  * the terms of the GNU General Public License as published by the Free Software
   7  * Foundation; either version 2 of the License, or (at your option) any later
   8  * version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  12  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  13  * details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  18  */
  19
  20 #include "uftps.h"
  21 #ifdef __MINGW32__
  22 #  include "hase.h"
  23 #else
  24 #  include <sys/stat.h>
  25 #endif
  26 #include <string.h>
  27
  28
  29 /*
  30  * Change the current working directory.  In practice, only the FTP path is
  31  * modified; without any chdir() call.  This way chroot emulation is achieved:
  32  * by explicitly controlling all paths.
  33  *
  34  * Even though the process working directory never changes, the issued path is
  35  * checked for existance in order to succeed.  Also, any client trie to traverse
  36  * the root by issuing ".." will be silently ignored, as expand_arg() swallows
  37  * every "." and ".." component.
  38  */
  39 void change_dir (void)
  40 {
  41         int          l, e;
  42         struct stat  s;
  43
  44         if (SS.arg == NULL)
  45         {
  46                 reply_c("501 Argument required.\r\n");
  47                 return;
  48         }
  49         l = expand_arg();
  50
  51         e = lstat(SS.arg, &s);
  52         if (e == -1 || !S_ISDIR(s.st_mode))
  53         {
  54                 if (e == -1)
  55                         error("Stating directory %s", SS.arg);
  56                 else
  57                         warning("Path %s is not a directory", SS.arg);
  58                 reply_c("550 Could not change directory.\r\n");
  59         }
  60         else
  61         {
  62 #ifdef __MINGW32__
  63                 /*
  64                  * Because we converted "./" to "." in expand_arg.c (Hasefroch
  65                  * idiot), now we must take care in reverting the change or we
  66                  * will brake future CWD and PWD responses.
  67                  */
  68                 if (l == 2)
  69                 {
  70                         SS.arg[l - 1] = '/';
  71                         SS.arg[l]     = '\0';
  72                         l++;
  73                 }
  74 #endif
  75                 memcpy(SS.cwd, SS.arg, l);
  76                 SS.cwd_len = l;
  77                 debug("Directory changed to %s", SS.cwd);
  78                 reply_c("250 Directory changed.\r\n");
  79         }
  80 }
  81