control.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 #include "uftps.h"
  20
  21 #include <errno.h>
  22 #include <unistd.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <ctype.h>
  26
  27 #include "command_parser.h"
  28
  29
  30 static void read_command (void)
  31 {
  32         int  l, i, b;
  33
  34         i = 0;
  35         l = SS.input_len;
  36         if (SS.input_offset > 0)
  37                 memmove(SS.input, SS.input + SS.input_offset, l);
  38
  39         do {
  40                 while (i < l && SS.input[i] != '\n')
  41                         i++;
  42                 if (SS.input[i] == '\n')
  43                 {
  44                         if (i > 0 && SS.input[i - 1] == '\r')
  45                                 break;
  46                         else
  47                                 continue;
  48                 }
  49
  50                 b = read(SS.control_sk, SS.input + l, LINE_SIZE - l);
  51                 if (b <= 0)
  52                 {
  53                         if (b == -1)
  54                                 fatal("Control channel input");
  55                         else if (l == LINE_SIZE)
  56                         {
  57                                 errno = 0;
  58                                 fatal("Input buffer overflow");
  59                         }
  60                         else
  61                         {
  62                                 notice("Peer closed control connection");
  63                                 exit(EXIT_SUCCESS);
  64                         }
  65                 }
  66
  67                 l += b;
  68         } while (1);
  69
  70         SS.input[i - 1] = '\0';
  71         SS.input[i]     = '\0';
  72         i++;
  73         SS.input_len    =  l - i;
  74         SS.input_offset = (l - i > 0 ? i : 0);
  75
  76         debug("Request '%s'", SS.input);
  77 }
  78
  79
  80 /*
  81  * Return the next command (as an integer) available in the control channel.
  82  */
  83 enum command next_command (void)
  84 {
  85         const struct Cmd  *cmd;
  86         int                i;
  87
  88         read_command();
  89
  90         i = 0;
  91         while (SS.input[i] != ' ' && SS.input[i] != '\0')
  92         {
  93                 SS.input[i] = toupper(SS.input[i] & 0x07F);
  94                 i++;
  95         }
  96
  97         SS.arg      = (SS.input[i] == ' ' ? SS.input + i + 1 : NULL);
  98         SS.input[i] = '\0';
  99
 100         cmd = parse_command(SS.input, i);
 101         if (cmd == NULL)
 102                 return FTP_NONE;
 103         return cmd->value;
 104 }
 105
 106
 107 /*
 108  * Send a reply to the peer over the control connection.
 109  */
 110 void reply (const char *str, int len)
 111 {
 112         int  b;
 113
 114         debug("Reply '%*s'", len - 2, str);
 115
 116         do {
 117                 b = write(SS.control_sk, str, len);
 118                 if (b == -1)
 119                         fatal("Control channel output");
 120
 121                 str += b;
 122                 len -= b;
 123         } while (len > 0);
 124 }
 125