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Diffstat (limited to '')
| -rw-r--r-- | pipe.c | 178 |
1 files changed, 178 insertions, 0 deletions
@@ -0,0 +1,178 @@ +/* + * 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; +} |