rsync/pipe.c

/*  -*- c-file-style: "linux" -*-
 * 
 * Copyright (C) 1996-2000 by Andrew Tridgell 
 * Copyright (C) Paul Mackerras 1996
 * Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "rsync.h"

/**
 * Create a child connected to use on stdin/stdout.
 *
 * This is derived from CVS code 
 * 
 * Note that in the child STDIN is set to blocking and STDOUT
 * is set to non-blocking. This is necessary as rsh relies on stdin being blocking
 *  and ssh relies on stdout being non-blocking
 *
 * If blocking_io is set then use blocking io on both fds. That can be
 * used to cope with badly broken rsh implementations like the one on
 * Solaris.
 **/
pid_t piped_child(char **command, int *f_in, int *f_out)
{
	pid_t pid;
	int to_child_pipe[2];
	int from_child_pipe[2];
	extern int blocking_io;
	
	if (verbose >= 2) {
		print_child_argv(command);
	}

	if (fd_pair(to_child_pipe) < 0 || fd_pair(from_child_pipe) < 0) {
		rprintf(FERROR, "pipe: %s\n", strerror(errno));
		exit_cleanup(RERR_IPC);
	}


	pid = do_fork();
	if (pid == -1) {
		rprintf(FERROR, "fork: %s\n", strerror(errno));
		exit_cleanup(RERR_IPC);
	}

	if (pid == 0) {
		extern int orig_umask;
		if (dup2(to_child_pipe[0], STDIN_FILENO) < 0 ||
		    close(to_child_pipe[1]) < 0 ||
		    close(from_child_pipe[0]) < 0 ||
		    dup2(from_child_pipe[1], STDOUT_FILENO) < 0) {
			rprintf(FERROR, "Failed to dup/close : %s\n",
				strerror(errno));
			exit_cleanup(RERR_IPC);
		}
		if (to_child_pipe[0] != STDIN_FILENO)
			close(to_child_pipe[0]);
		if (from_child_pipe[1] != STDOUT_FILENO)
			close(from_child_pipe[1]);
		umask(orig_umask);
		set_blocking(STDIN_FILENO);
		if (blocking_io) {
			set_blocking(STDOUT_FILENO);
		}
		execvp(command[0], command);
		rprintf(FERROR, "Failed to exec %s : %s\n",
			command[0], strerror(errno));
		exit_cleanup(RERR_IPC);
	}

	if (close(from_child_pipe[1]) < 0 || close(to_child_pipe[0]) < 0) {
		rprintf(FERROR, "Failed to close : %s\n", strerror(errno));
		exit_cleanup(RERR_IPC);
	}

	*f_in = from_child_pipe[0];
	*f_out = to_child_pipe[1];

	return pid;
}

pid_t local_child(int argc, char **argv,int *f_in,int *f_out,
		  int (*child_main)(int, char*[]))
{
	pid_t pid;
	int to_child_pipe[2];
	int from_child_pipe[2];
	extern int read_batch;  /* dw */

	if (fd_pair(to_child_pipe) < 0 ||
	    fd_pair(from_child_pipe) < 0) {
		rprintf(FERROR,"pipe: %s\n",strerror(errno));
		exit_cleanup(RERR_IPC);
	}


	pid = do_fork();
	if (pid == -1) {
		rprintf(FERROR,"fork: %s\n",strerror(errno));
		exit_cleanup(RERR_IPC);
	}

	if (pid == 0) {
		extern int am_sender;
		extern int am_server;

		am_sender = read_batch ? 0 : !am_sender;
		am_server = 1;		

		if (dup2(to_child_pipe[0], STDIN_FILENO) < 0 ||
		    close(to_child_pipe[1]) < 0 ||
		    close(from_child_pipe[0]) < 0 ||
		    dup2(from_child_pipe[1], STDOUT_FILENO) < 0) {
			rprintf(FERROR,"Failed to dup/close : %s\n",strerror(errno));
			exit_cleanup(RERR_IPC);
		}
		if (to_child_pipe[0] != STDIN_FILENO) close(to_child_pipe[0]);
		if (from_child_pipe[1] != STDOUT_FILENO) close(from_child_pipe[1]);
		child_main(argc, argv);
	}

	if (close(from_child_pipe[1]) < 0 ||
	    close(to_child_pipe[0]) < 0) {
		rprintf(FERROR,"Failed to close : %s\n",strerror(errno));   
		exit_cleanup(RERR_IPC);
	}

	*f_in = from_child_pipe[0];
	*f_out = to_child_pipe[1];
  
	return pid;
}