main-unix.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 <sys/socket.h>
  22 #include <sys/wait.h>
  23 #include <signal.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28
  29 struct _SessionScope  SS;  /* SS --> Session State*/
  30
  31
  32 /*
  33  * clid_finish
  34  *
  35  * Reaper function.  For "zombies".
  36  */
  37 static void child_finish (int sig)
  38 {
  39         while (waitpid(-1, NULL, WNOHANG) > 0)
  40                 debug("Collecting children");
  41 }
  42
  43
  44 /*
  45  * end
  46  *
  47  * End. What where you expecting?
  48  */
  49 static void end (int sig)
  50 {
  51         notice("Signal caught, exiting");
  52         exit(EXIT_SUCCESS);
  53 }
  54
  55
  56 /*
  57  * Main program.
  58  */
  59 int main (int argc, char **argv)
  60 {
  61         int                 bind_sk, cmd_sk, e, yes;
  62         int                 port = DEFAULT_PORT;
  63         struct sigaction    my_sa;
  64         struct sockaddr_in  sai;
  65         socklen_t           sai_len = sizeof(struct sockaddr_in);
  66
  67         if (argc > 1)
  68         {
  69                 port = atoi(argv[1]) & 0x00FFFF;
  70                 if (port <= 1024)
  71                 {
  72                         errno = 0;
  73                         fatal("Invalid port number");
  74                 }
  75         }
  76
  77         /* Signal handling */
  78         sigfillset(&my_sa.sa_mask);
  79         my_sa.sa_flags   = SA_RESTART;
  80         my_sa.sa_handler = child_finish;
  81         sigaction(SIGCHLD, &my_sa, NULL);
  82
  83         sigemptyset(&my_sa.sa_mask);
  84         my_sa.sa_flags   = 0;
  85         my_sa.sa_handler = end;
  86         sigaction(SIGINT,  &my_sa, NULL);
  87         sigaction(SIGTERM, &my_sa, NULL);
  88
  89         /* Connection handling, preparing to serve */
  90         sai.sin_family      = AF_INET;
  91         sai.sin_port        = htons(port);
  92         sai.sin_addr.s_addr = INADDR_ANY;
  93
  94         bind_sk = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  95         if (bind_sk == -1)
  96                 fatal("Creating main server socket");
  97
  98         yes = 1;
  99         setsockopt(bind_sk, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
 100         e = bind(bind_sk, (struct sockaddr *) &sai, sai_len);
 101         if (e == -1)
 102                 fatal("Binding main server socket");
 103
 104         e = listen(bind_sk, 5);
 105         if (e == -1)
 106                 fatal("Listening at main server socket");
 107
 108         notice("UFTPS listening on port %d (TCP)", port);
 109         notice("Use CTRL + C to finish");
 110         notice("If you want to use a different port, specify it as the only argument in the command line");
 111
 112         /* Main server loop (accepting connections) */
 113         do {
 114                 sai_len = sizeof(struct sockaddr_in);
 115                 cmd_sk  = accept(bind_sk, (struct sockaddr *) &sai, &sai_len);
 116                 if (cmd_sk == -1)
 117                 {
 118                         if (errno != EINTR)
 119                                 error("Accepting incoming connection");
 120                         continue;
 121                 }
 122
 123                 e = fork();
 124                 if (e == 0)
 125                 {
 126                         /***  CHILD  ***/
 127                         close(bind_sk);
 128                         init_session(cmd_sk);
 129                         command_loop();
 130                 }
 131                 else
 132                 {
 133                         /***  PARENT  ***/
 134                         if (e == -1)
 135                                 error("Could not create a child process");
 136                         close(cmd_sk);
 137                 }
 138         } while (1);
 139
 140         return EXIT_SUCCESS;
 141 }
 142