command_loop.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 #include <ctype.h>
  22 #include <unistd.h>
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25
  26
  27 /*
  28  * Main FTP server loop.  The switch should be converted to an indexed jump
  29  * because the command values are consecutive integers.  Thus avoiding the
  30  * multiple string comparisons.
  31  *
  32  * This function never returns.
  33  */
  34 void command_loop (void)
  35 {
  36         int  l;
  37
  38         do {
  39                 switch (next_command())
  40                 {
  41                 /*
  42                  * Straightforward implementations.
  43                  */
  44                 case FTP_NOOP:
  45                         reply_c("200 I'm alive, don't worry\r\n");
  46                         break;
  47
  48                 case FTP_FEAT:
  49                         reply_c("211-Feature list:\r\n"
  50                                 "211- MDTM\r\n"
  51                                 "211- REST STREAM\r\n"
  52                                 "211- SIZE\r\n"
  53                                 "211- TVFS\r\n"
  54                                 "211 End.\r\n");
  55                         break;
  56
  57                 case FTP_SYST:
  58                         reply_c("215 UNIX Type: L8\r\n");
  59                         break;
  60
  61                 case FTP_PASS:
  62                 case FTP_USER:
  63                         reply_c("230 I don't care.\r\n");
  64                         break;
  65
  66                 case FTP_OPTS:
  67                         reply_c("501 Option not understood.\r\n");
  68                         break;
  69
  70                 case FTP_ACCT:
  71                 case FTP_SMNT:
  72                         reply_c("202 Unimplemented, ignored.\r\n");
  73                         break;
  74
  75                 case FTP_REIN:
  76                         reply_c("220 Nothing to REIN.\r\n");
  77                         break;
  78
  79                 /*
  80                  * A bit more complex commands.
  81                  */
  82                 case FTP_MODE:
  83                         if (toupper(SS.arg[0]) == 'S')
  84                                 reply_c("200 MODE set to stream.\r\n");
  85                         else
  86                                 reply_c("504 Mode not supported.\r\n");
  87                         break;
  88
  89                 case FTP_STRU:
  90                         if (toupper(SS.arg[0]) == 'F')
  91                                 reply_c("200 STRUcture set to file.\r\n");
  92                         else
  93                                 reply_c("504 Structure not supported.\r\n");
  94                         break;
  95
  96                 case FTP_TYPE:
  97                         switch (toupper(SS.arg[0]))
  98                         {
  99                                 case 'I':
 100                                 case 'A':
 101                                 case 'L': reply_c("200 Whatever.\r\n"); break;
 102                                 default : reply_c("504 Type not supported.\r\n");
 103                         }
 104                         break;
 105
 106                 case FTP_PWD:
 107                         l = snprintf(SS.aux, LINE_SIZE, "257 \"%s\"\r\n", &SS.cwd[1]);
 108                         reply(SS.aux, l);
 109                         break;
 110
 111                 case FTP_REST:
 112                         /* We don't need str_to_ll() as sscanf() does de job */
 113                         sscanf(SS.arg, "%lld", (long long *) &SS.file_offset);
 114                         l = snprintf(SS.aux, LINE_SIZE, "350 Got it (%lld).\r\n",
 115                                      (long long) SS.file_offset);
 116                         reply(SS.aux, l);
 117                         break;
 118
 119                 case FTP_QUIT:
 120                         reply_c("221 Goodbye.\r\n");
 121                         close(SS.control_sk);
 122                         if (SS.passive_sk != -1)
 123                                 close(SS.passive_sk);
 124                         exit(EXIT_SUCCESS);
 125                         break;
 126
 127                 /*
 128                  * Complex commands implemented separately.
 129                  */
 130                 case FTP_PORT:
 131                         parse_port_argument();
 132                         break;
 133
 134                 case FTP_PASV:
 135                         enable_passive();
 136                         break;
 137
 138                 case FTP_CWD:
 139                         change_dir();
 140                         break;
 141
 142                 case FTP_NLST:
 143                         list_dir(0);
 144                         break;
 145
 146                 case FTP_LIST:
 147                         list_dir(1);
 148                         break;
 149
 150                 case FTP_MDTM:
 151                         file_stats(0);
 152                         break;
 153
 154                 case FTP_SIZE:
 155                         file_stats(1);
 156                         break;
 157
 158                 case FTP_RETR:
 159                         send_file();
 160                         break;
 161
 162                 /*
 163                  * Unrecognized or unimplemented commands.
 164                  */
 165                 case FTP_NONE:
 166                         reply_c("500 Command unrecognized.\r\n");
 167                         break;
 168
 169                 default:
 170                         reply_c("502 Command not implemented.\r\n");
 171                 }
 172         } while (1);
 173 }
 174