send_file.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 /*
  22  * RETR command implementation.  It uses sendfile() because seems quite optimal,
  23  * just as VsFTPd does.
  24  *
  25  * Same restrictions, as in change_dir.c, apply for the argument.  See that file
  26  * for more details.
  27  *
  28  * Usually, a client sends a PASV command then immediately connects to the port
  29  * indicated by the server reply.  If we are continuously reusing the same port
  30  * for passive data connections, we have to open whether theres is error or not
  31  * to shift one position in the connection wait queue.
  32  */
  33
  34 #include <sys/types.h>
  35 #include <sys/stat.h>
  36 #include <sys/socket.h>
  37 #include <sys/sendfile.h>
  38 #include <netinet/in.h>
  39 #include <unistd.h>
  40 #include <fcntl.h>
  41
  42
  43 void send_file (void)
  44 {
  45         int                fd, err;
  46         struct sockaddr_in saddr;
  47         struct stat        st;
  48         socklen_t          slen = sizeof(saddr);
  49
  50         if (SS.passive_mode)
  51                 SS.data_sk = accept(SS.passive_sk, (struct sockaddr *) &saddr,
  52                                     &slen);
  53
  54         if (SS.arg == NULL)
  55         {
  56                 reply_c("501 Argument required.\r\n");
  57                 goto finish;
  58         }
  59
  60         expand_arg();
  61         fd = open(SS.arg, O_RDONLY, 0);
  62
  63         if (fd == -1)
  64         {
  65                 reply_c("550 Could not open file.\r\n");
  66                 goto finish;
  67         }
  68
  69         err = fstat(fd, &st);
  70         if (err == -1 || !S_ISREG(st.st_mode))
  71         {
  72                 reply_c("550 Could not stat file.\r\n");
  73                 goto finish;
  74         }
  75
  76         reply_c("150 Sending file content.\r\n");
  77
  78         /* Apply a possible previous REST command.  Ignore errors, is it allowd
  79          * by the RFC? */
  80         if (SS.file_offset > 0)
  81                 lseek(fd, SS.file_offset, SEEK_SET);
  82
  83         while (SS.file_offset < st.st_size)
  84         {
  85                 debug("Offset step: %lld", SS.file_offset);
  86
  87                 err = sendfile(SS.data_sk, fd, &SS.file_offset, INT_MAX);
  88                 if (err == -1)
  89                         fatal("Could not send file");
  90         }
  91
  92         debug("Offset end: %lld", SS.file_offset);
  93
  94         reply_c("226 File content sent.\r\n");
  95
  96 finish:
  97         close(SS.data_sk);
  98         SS.passive_mode = 0;
  99         SS.file_offset  = 0;
 100         SS.data_sk      = -1;
 101 }
 102