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/* -*- c-file-style: "java"; indent-tabs-mode: nil; tab-width: 4; fill-column: 78 -*-
*
* distcc -- A simple distributed compiler system
*
* Copyright (C) 2001-2004 by Martin Pool
* Copyright (C) 1996-2001 by Andrew Tridgell
* Copyright (C) 1996 by Paul Mackerras
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
/*
* ssh.c -- Open a connection a server over ssh or something similar.
*
* The ssh connection always opens immediately from distcc's point of view,
* because the local socket/pipe to the child is ready. If the remote
* connection failed or is slow, distcc will only know when it tries to read
* or write. (And in fact the first page or more written will go out
* immediately too...)
*
* This file always uses nonblocking ssh, which has proven in rsync to be the
* better solution for ssh. It may cause trouble with ancient proprietary rsh
* implementations which can't handle their input being in nonblocking mode.
* rsync has a configuration option for that, but I don't support it here,
* because there's no point using rsh, you might as well use the native
* protocol.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include "distcc.h"
#include "trace.h"
#include "exitcode.h"
#include "util.h"
#include "exec.h"
#include "snprintf.h"
#include "netutil.h"
const char *dcc_default_ssh = "ssh";
/**
* Create a file descriptor pair - like pipe() but use socketpair if
* possible (because of blocking issues on pipes).
*
* Always set non-blocking.
*/
static int fd_pair(int fd[2])
{
int ret;
#if HAVE_SOCKETPAIR
ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
#else
ret = pipe(fd);
#endif
if (ret == 0) {
dcc_set_nonblocking(fd[0]);
dcc_set_nonblocking(fd[1]);
}
return ret;
}
/**
* 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
**/
static int dcc_run_piped_cmd(char **argv,
int *f_in,
int *f_out,
pid_t * child_pid)
{
pid_t pid;
int to_child_pipe[2];
int from_child_pipe[2];
dcc_trace_argv("execute", argv);
if (fd_pair(to_child_pipe) < 0) {
rs_log_error("fd_pair: %s", strerror(errno));
return EXIT_IO_ERROR;
}
if (fd_pair(from_child_pipe) < 0) {
dcc_close(to_child_pipe[0]);
dcc_close(to_child_pipe[1]);
rs_log_error("fd_pair: %s", strerror(errno));
return EXIT_IO_ERROR;
}
*child_pid = pid = fork();
if (pid == -1) {
rs_log_error("fork failed: %s", strerror(errno));
dcc_close(to_child_pipe[0]);
dcc_close(to_child_pipe[1]);
dcc_close(from_child_pipe[0]);
dcc_close(from_child_pipe[1]);
return EXIT_IO_ERROR;
}
if (pid == 0) {
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) {
rs_log_error("dup/close: %s", strerror(errno));
return EXIT_IO_ERROR;
}
if (to_child_pipe[0] != STDIN_FILENO)
close(to_child_pipe[0]);
if (from_child_pipe[1] != STDOUT_FILENO)
close(from_child_pipe[1]);
dcc_set_blocking(STDIN_FILENO);
execvp(argv[0], (char **) argv);
rs_log_error("failed to exec %s: %s", argv[0], strerror(errno));
return EXIT_IO_ERROR;
}
if (dcc_close(from_child_pipe[1]) || dcc_close(to_child_pipe[0])) {
rs_log_error("failed to close pipes");
return EXIT_IO_ERROR;
}
*f_in = from_child_pipe[0];
*f_out = to_child_pipe[1];
return 0;
}
/**
* Open a connection to a remote machine over ssh.
*
* Based on code in rsync, but rewritten.
*
* @note The tunnel command is always opened directly using execvp(), not
* through a shell. So you cannot pass shell operators like redirections, and
* at the moment you cannot specify additional options. Perhaps it would be
* nice for us to parse it into an argv[] string by splitting on
* wildcards/quotes, but at the moment this seems redundant. It can be done
* adequately using .ssh/config I think.
**/
int dcc_ssh_connect(char *ssh_cmd,
char *user,
char *machine,
char *path,
int *f_in, int *f_out,
pid_t *ssh_pid)
{
pid_t ret;
char *child_argv[10];
int i;
/* We need to cast away constness. I promise the strings in the argv[]
* will not be modified. */
if (!ssh_cmd)
ssh_cmd = getenv("DISTCC_SSH");
if (!ssh_cmd)
ssh_cmd = (char *) dcc_default_ssh;
if (!machine) {
rs_log_crit("no machine defined!");
return EXIT_DISTCC_FAILED;
}
if (!path)
path = (char *) "distccd";
i = 0;
child_argv[i++] = ssh_cmd;
if (user) {
child_argv[i++] = (char *) "-l";
child_argv[i++] = user;
}
child_argv[i++] = machine;
child_argv[i++] = path;
child_argv[i++] = (char *) "--inetd";
child_argv[i++] = NULL;
rs_trace("connecting to %s using %s", machine, ssh_cmd);
/* TODO: If we're verbose, perhaps make the server verbose too, and send
* its log to our stderr? */
/* child_argv[i++] = (char *) "--log-stderr"; */
ret = dcc_run_piped_cmd(child_argv, f_in, f_out, ssh_pid);
return ret;
}
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