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 void command_loop (void)
  33 {
  34         int  e, l;
  35
  36         do {
  37                 switch (next_command())
  38                 {
  39                 /*
  40                  * Straightforward implementations.
  41                  */
  42                 case FTP_NOOP:
  43                         reply_c("200 I'm alive, don't worry\r\n");
  44                         break;
  45
  46                 case FTP_FEAT:
  47                         reply_c("211-Feature list:\r\n"
  48                                 "211- MDTM\r\n"
  49                                 "211- REST STREAM\r\n"
  50                                 "211- SIZE\r\n"
  51                                 "211- TVFS\r\n"
  52                                 "211 End.\r\n");
  53                         break;
  54
  55                 case FTP_SYST:
  56                         reply_c("215 UNIX Type: L8\r\n");
  57                         break;
  58
  59                 case FTP_PASS:
  60                 case FTP_USER:
  61                         reply_c("230 I don't care.\r\n");
  62                         break;
  63
  64                 case FTP_OPTS:
  65                         reply_c("501 Option not understood.\r\n");
  66                         break;
  67
  68                 case FTP_ACCT:
  69                 case FTP_SMNT:
  70                         reply_c("202 Unimplemented, ignored.\r\n");
  71                         break;
  72
  73                 case FTP_REIN:
  74                         reply_c("220 Nothing to REIN.\r\n");
  75                         break;
  76
  77                 /*
  78                  * A bit more complex commands.
  79                  */
  80                 case FTP_MODE:
  81                         if (toupper(SS.arg[0]) == 'S')
  82                                 reply_c("200 MODE set to stream.\r\n");
  83                         else
  84                                 reply_c("504 Mode not supported.\r\n");
  85                         break;
  86
  87                 case FTP_STRU:
  88                         if (toupper(SS.arg[0]) == 'F')
  89                                 reply_c("200 STRUcture set to file.\r\n");
  90                         else
  91                                 reply_c("504 Structure not supported.\r\n");
  92                         break;
  93
  94                 case FTP_TYPE:
  95                         switch (toupper(SS.arg[0]))
  96                         {
  97                                 case 'I':
  98                                 case 'A':
  99                                 case 'L': reply_c("200 Whatever.\r\n"); break;
 100                                 default : reply_c("504 Type not supported.\r\n");
 101                         }
 102                         break;
 103
 104                 case FTP_PWD:
 105                         l = snprintf(SS.aux, LINE_SIZE, "257 \"%s\"\r\n", &SS.cwd[1]);
 106                         reply(SS.aux, l);
 107                         break;
 108
 109                 case FTP_REST:
 110                         /* We don't need str_to_ll() as sscanf() does de job */
 111                         sscanf(SS.arg, "%lld", (long long *) &SS.file_offset);
 112                         l = snprintf(SS.aux, LINE_SIZE, "350 Got it (%lld).\r\n",
 113                                      (long long) SS.file_offset);
 114                         reply(SS.aux, l);
 115                         break;
 116
 117                 case FTP_QUIT:
 118                         reply_c("221 Goodbye.\r\n");
 119                         e = close(SS.control_sk);
 120                         if (e == -1)
 121                                 error("Closing control channel");
 122
 123                         if (SS.passive_sk != -1)
 124                         {
 125                                 e = close(SS.passive_sk);
 126                                 if (e == -1)
 127                                         error("Closing passive socket");
 128                         }
 129                         exit(EXIT_SUCCESS);
 130                         break;
 131
 132                 /*
 133                  * Complex commands implemented separately.
 134                  */
 135                 case FTP_PORT:
 136                         parse_port_argument();
 137                         break;
 138
 139                 case FTP_PASV:
 140                         enable_passive();
 141                         break;
 142
 143                 case FTP_NLST:
 144                         list_dir(0);
 145                         break;
 146
 147                 case FTP_LIST:
 148                         list_dir(1);
 149                         break;
 150
 151                 case FTP_MDTM:
 152                         file_stats(0);
 153                         break;
 154
 155                 case FTP_SIZE:
 156                         file_stats(1);
 157                         break;
 158
 159                 case FTP_CWD:
 160                         change_dir();
 161                         break;
 162
 163                 case FTP_RETR:
 164                         send_file();
 165                         break;
 166
 167                 case FTP_NONE:
 168                         reply_c("500 Command unrecognized.\r\n");
 169                         break;
 170
 171                 default:
 172                         reply_c("502 Command not implemented.\r\n");
 173                 }
 174         } while (1);
 175 }
 176