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 /**
  25  * Create a child connected to use on stdin/stdout.
  26  *
  27  * This is derived from CVS code
  28  *
  29  * Note that in the child STDIN is set to blocking and STDOUT
  30  * is set to non-blocking. This is necessary as rsh relies on stdin being blocking
  31  *  and ssh relies on stdout being non-blocking
  32  *
  33  * If blocking_io is set then use blocking io on both fds. That can be
  34  * used to cope with badly broken rsh implementations like the one on
  35  * Solaris.
  36  **/
  37 pid_t piped_child(char **command, int *f_in, int *f_out)
  38 {
  39         pid_t pid;
  40         int to_child_pipe[2];
  41         int from_child_pipe[2];
  42         extern int blocking_io;
  43
  44         if (verbose >= 2) {
  45                 print_child_argv(command);
  46         }
  47
  48         if (fd_pair(to_child_pipe) < 0 || fd_pair(from_child_pipe) < 0) {
  49                 rprintf(FERROR, "pipe: %s\n", strerror(errno));
  50                 exit_cleanup(RERR_IPC);
  51         }
  52
  53
  54         pid = do_fork();
  55         if (pid == -1) {
  56                 rprintf(FERROR, "fork: %s\n", strerror(errno));
  57                 exit_cleanup(RERR_IPC);
  58         }
  59
  60         if (pid == 0) {
  61                 extern int orig_umask;
  62                 if (dup2(to_child_pipe[0], STDIN_FILENO) < 0 ||
  63                     close(to_child_pipe[1]) < 0 ||
  64                     close(from_child_pipe[0]) < 0 ||
  65                     dup2(from_child_pipe[1], STDOUT_FILENO) < 0) {
  66                         rprintf(FERROR, "Failed to dup/close : %s\n",
  67                                 strerror(errno));
  68                         exit_cleanup(RERR_IPC);
  69                 }
  70                 if (to_child_pipe[0] != STDIN_FILENO)
  71                         close(to_child_pipe[0]);
  72                 if (from_child_pipe[1] != STDOUT_FILENO)
  73                         close(from_child_pipe[1]);
  74                 umask(orig_umask);
  75                 set_blocking(STDIN_FILENO);
  76                 if (blocking_io) {
  77                         set_blocking(STDOUT_FILENO);
  78                 }
  79                 execvp(command[0], command);
  80                 rprintf(FERROR, "Failed to exec %s : %s\n",
  81                         command[0], strerror(errno));
  82                 exit_cleanup(RERR_IPC);
  83         }
  84
  85         if (close(from_child_pipe[1]) < 0 || close(to_child_pipe[0]) < 0) {
  86                 rprintf(FERROR, "Failed to close : %s\n", strerror(errno));
  87                 exit_cleanup(RERR_IPC);
  88         }
  89
  90         *f_in = from_child_pipe[0];
  91         *f_out = to_child_pipe[1];
  92
  93         return pid;
  94 }
  95
  96 pid_t local_child(int argc, char **argv,int *f_in,int *f_out,
  97                   int (*child_main)(int, char*[]))
  98 {
  99         pid_t pid;
 100         int to_child_pipe[2];
 101         int from_child_pipe[2];
 102         extern int read_batch;
 103         extern int am_sender;
 104         extern int am_server;
 105         extern int filesfrom_fd;
 106
 107         if (fd_pair(to_child_pipe) < 0 ||
 108             fd_pair(from_child_pipe) < 0) {
 109                 rprintf(FERROR,"pipe: %s\n",strerror(errno));
 110                 exit_cleanup(RERR_IPC);
 111         }
 112
 113
 114         pid = do_fork();
 115         if (pid == -1) {
 116                 rprintf(FERROR,"fork: %s\n",strerror(errno));
 117                 exit_cleanup(RERR_IPC);
 118         }
 119
 120         if (pid == 0) {
 121                 am_sender = read_batch ? 0 : !am_sender;
 122                 am_server = 1;
 123
 124                 if (!am_sender)
 125                         filesfrom_fd = -1;
 126
 127                 if (dup2(to_child_pipe[0], STDIN_FILENO) < 0 ||
 128                     close(to_child_pipe[1]) < 0 ||
 129                     close(from_child_pipe[0]) < 0 ||
 130                     dup2(from_child_pipe[1], STDOUT_FILENO) < 0) {
 131                         rprintf(FERROR,"Failed to dup/close : %s\n",strerror(errno));
 132                         exit_cleanup(RERR_IPC);
 133                 }
 134                 if (to_child_pipe[0] != STDIN_FILENO) close(to_child_pipe[0]);
 135                 if (from_child_pipe[1] != STDOUT_FILENO) close(from_child_pipe[1]);
 136                 child_main(argc, argv);
 137         }
 138
 139         if (!am_sender)
 140                 filesfrom_fd = -1;
 141
 142         if (close(from_child_pipe[1]) < 0 ||
 143             close(to_child_pipe[0]) < 0) {
 144                 rprintf(FERROR,"Failed to close : %s\n",strerror(errno));
 145                 exit_cleanup(RERR_IPC);
 146         }
 147
 148         *f_in = from_child_pipe[0];
 149         *f_out = to_child_pipe[1];
 150
 151         return pid;
 152 }