send_file-splice.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 <unistd.h>
  22 #define __USE_GNU
  23 #include <fcntl.h>
  24
  25
  26 /*
  27  * RETR command implementation using Linux new splice() system call to minimize
  28  * memory copies.  Due to the nature of the system call, it is not even
  29  * necessary to perform the initial seek in case a REST command was issued.
  30  */
  31 void send_file (void)
  32 {
  33         int    f;
  34         long   e;
  35         off_t  size, completed;
  36
  37         completed      = SS.file_offset;
  38         SS.file_offset = 0;
  39
  40         f = open_file(&size);
  41         if (f == -1)
  42                 return;
  43
  44         e = open_data_channel();
  45         if (e == -1)
  46         {
  47                 close(f);
  48                 return;
  49         }
  50
  51         reply_c("150 Sending file content.\r\n");
  52
  53         /* Main transfer loop */
  54         while (completed < size && e != -1)
  55         {
  56                 debug("Offset is %lld", (long long) completed);
  57                 e = splice(f, &completed, SS.data_sk, NULL, INT_MAX,
  58                            SPLICE_F_MOVE);
  59         }
  60
  61         if (e != -1)
  62                 reply_c("226 File content sent.\r\n");
  63         else
  64         {
  65                 error("Sending file %s", SS.arg);
  66                 reply_c("426 Connection closed, transfer aborted.\r\n");
  67         }
  68
  69         close(f);
  70         closesocket(SS.data_sk);
  71         SS.data_sk = -1;
  72 }
  73