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/*
* Routines used to setup various kinds of inter-process pipes.
*
* Copyright (C) 1996-2000 Andrew Tridgell
* Copyright (C) 1996 Paul Mackerras
* Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
* Copyright (C) 2004-2020 Wayne Davison
*
* 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 3 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, visit the http://fsf.org website.
*/
#include "rsync.h"
extern int am_sender;
extern int am_server;
extern int blocking_io;
extern int filesfrom_fd;
extern int munge_symlinks;
extern char *logfile_name;
extern int remote_option_cnt;
extern const char **remote_options;
extern struct chmod_mode_struct *chmod_modes;
/**
* Create a child connected to us via its 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];
if (DEBUG_GTE(CMD, 1))
print_child_argv("opening connection using:", command);
if (fd_pair(to_child_pipe) < 0 || fd_pair(from_child_pipe) < 0) {
rsyserr(FERROR, errno, "pipe");
exit_cleanup(RERR_IPC);
}
pid = do_fork();
if (pid == -1) {
rsyserr(FERROR, errno, "fork");
exit_cleanup(RERR_IPC);
}
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) {
rsyserr(FERROR, errno, "Failed to dup/close");
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]);
set_blocking(STDIN_FILENO);
if (blocking_io > 0)
set_blocking(STDOUT_FILENO);
execvp(command[0], command);
rsyserr(FERROR, errno, "Failed to exec %s", command[0]);
exit_cleanup(RERR_IPC);
}
if (close(from_child_pipe[1]) < 0 || close(to_child_pipe[0]) < 0) {
rsyserr(FERROR, errno, "Failed to close");
exit_cleanup(RERR_IPC);
}
*f_in = from_child_pipe[0];
*f_out = to_child_pipe[1];
return pid;
}
/* This function forks a child which calls child_main(). First,
* however, it has to establish communication paths to and from the
* newborn child. It creates two socket pairs -- one for writing to
* the child (from the parent) and one for reading from the child
* (writing to the parent). Since that's four socket ends, each
* process has to close the two ends it doesn't need. The remaining
* two socket ends are retained for reading and writing. In the
* child, the STDIN and STDOUT file descriptors refer to these
* sockets. In the parent, the function arguments f_in and f_out are
* set to refer to these sockets. */
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];
/* The parent process is always the sender for a local rsync. */
assert(am_sender);
if (fd_pair(to_child_pipe) < 0 || fd_pair(from_child_pipe) < 0) {
rsyserr(FERROR, errno, "pipe");
exit_cleanup(RERR_IPC);
}
pid = do_fork();
if (pid == -1) {
rsyserr(FERROR, errno, "fork");
exit_cleanup(RERR_IPC);
}
if (pid == 0) {
am_sender = 0;
am_server = 1;
filesfrom_fd = -1;
munge_symlinks = 0; /* Each side needs its own option. */
chmod_modes = NULL; /* Let the sending side handle this. */
/* Let the client side handle this. */
if (logfile_name) {
logfile_name = NULL;
logfile_close();
}
if (remote_option_cnt) {
int rc = remote_option_cnt + 1;
const char **rv = remote_options;
if (!parse_arguments(&rc, &rv)) {
option_error();
exit_cleanup(RERR_SYNTAX);
}
}
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) {
rsyserr(FERROR, errno, "Failed to dup/close");
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]);
#ifdef ICONV_CONST
setup_iconv();
#endif
child_main(argc, argv);
}
if (close(from_child_pipe[1]) < 0 || close(to_child_pipe[0]) < 0) {
rsyserr(FERROR, errno, "Failed to close");
exit_cleanup(RERR_IPC);
}
*f_in = from_child_pipe[0];
*f_out = to_child_pipe[1];
return pid;
}
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