pipe.c

   1 /*  -*- c-file-style: "linux" -*-
   2  *
   3  * Copyright (C) 1996-2000 by Andrew Tridgell
   4  * Copyright (C) Paul Mackerras 1996
   5  * Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include "rsync.h"
  23
  24 extern int am_sender;
  25 extern int am_server;
  26 extern int blocking_io;
  27 extern int orig_umask;
  28 extern int read_batch;
  29 extern int filesfrom_fd;
  30
  31 /**
  32  * Create a child connected to use on stdin/stdout.
  33  *
  34  * This is derived from CVS code
  35  *
  36  * Note that in the child STDIN is set to blocking and STDOUT
  37  * is set to non-blocking. This is necessary as rsh relies on stdin being blocking
  38  *  and ssh relies on stdout being non-blocking
  39  *
  40  * If blocking_io is set then use blocking io on both fds. That can be
  41  * used to cope with badly broken rsh implementations like the one on
  42  * Solaris.
  43  **/
  44 pid_t piped_child(char **command, int *f_in, int *f_out)
  45 {
  46         pid_t pid;
  47         int to_child_pipe[2];
  48         int from_child_pipe[2];
  49
  50         if (verbose >= 2) {
  51                 print_child_argv(command);
  52         }
  53
  54         if (fd_pair(to_child_pipe) < 0 || fd_pair(from_child_pipe) < 0) {
  55                 rsyserr(FERROR, errno, "pipe");
  56                 exit_cleanup(RERR_IPC);
  57         }
  58
  59         pid = do_fork();
  60         if (pid == -1) {
  61                 rsyserr(FERROR, errno, "fork");
  62                 exit_cleanup(RERR_IPC);
  63         }
  64
  65         if (pid == 0) {
  66                 if (dup2(to_child_pipe[0], STDIN_FILENO) < 0 ||
  67                     close(to_child_pipe[1]) < 0 ||
  68                     close(from_child_pipe[0]) < 0 ||
  69                     dup2(from_child_pipe[1], STDOUT_FILENO) < 0) {
  70                         rsyserr(FERROR, errno, "Failed to dup/close");
  71                         exit_cleanup(RERR_IPC);
  72                 }
  73                 if (to_child_pipe[0] != STDIN_FILENO)
  74                         close(to_child_pipe[0]);
  75                 if (from_child_pipe[1] != STDOUT_FILENO)
  76                         close(from_child_pipe[1]);
  77                 umask(orig_umask);
  78                 set_blocking(STDIN_FILENO);
  79                 if (blocking_io > 0)
  80                         set_blocking(STDOUT_FILENO);
  81                 execvp(command[0], command);
  82                 rsyserr(FERROR, errno, "Failed to exec %s", command[0]);
  83                 exit_cleanup(RERR_IPC);
  84         }
  85
  86         if (close(from_child_pipe[1]) < 0 || close(to_child_pipe[0]) < 0) {
  87                 rsyserr(FERROR, errno, "Failed to close");
  88                 exit_cleanup(RERR_IPC);
  89         }
  90
  91         *f_in = from_child_pipe[0];
  92         *f_out = to_child_pipe[1];
  93
  94         return pid;
  95 }
  96
  97 pid_t local_child(int argc, char **argv,int *f_in,int *f_out,
  98                   int (*child_main)(int, char*[]))
  99 {
 100         pid_t pid;
 101         int to_child_pipe[2];
 102         int from_child_pipe[2];
 103
 104         if (fd_pair(to_child_pipe) < 0 ||
 105             fd_pair(from_child_pipe) < 0) {
 106                 rsyserr(FERROR, errno, "pipe");
 107                 exit_cleanup(RERR_IPC);
 108         }
 109
 110         pid = do_fork();
 111         if (pid == -1) {
 112                 rsyserr(FERROR, errno, "fork");
 113                 exit_cleanup(RERR_IPC);
 114         }
 115
 116         if (pid == 0) {
 117                 am_sender = read_batch ? 0 : !am_sender;
 118                 am_server = 1;
 119
 120                 if (!am_sender)
 121                         filesfrom_fd = -1;
 122
 123                 if (dup2(to_child_pipe[0], STDIN_FILENO) < 0 ||
 124                     close(to_child_pipe[1]) < 0 ||
 125                     close(from_child_pipe[0]) < 0 ||
 126                     dup2(from_child_pipe[1], STDOUT_FILENO) < 0) {
 127                         rsyserr(FERROR, errno, "Failed to dup/close");
 128                         exit_cleanup(RERR_IPC);
 129                 }
 130                 if (to_child_pipe[0] != STDIN_FILENO)
 131                         close(to_child_pipe[0]);
 132                 if (from_child_pipe[1] != STDOUT_FILENO)
 133                         close(from_child_pipe[1]);
 134                 child_main(argc, argv);
 135         }
 136
 137         if (!am_sender)
 138                 filesfrom_fd = -1;
 139
 140         if (close(from_child_pipe[1]) < 0 ||
 141             close(to_child_pipe[0]) < 0) {
 142                 rsyserr(FERROR, errno, "Failed to close");
 143                 exit_cleanup(RERR_IPC);
 144         }
 145
 146         *f_in = from_child_pipe[0];
 147         *f_out = to_child_pipe[1];
 148
 149         return pid;
 150 }