Annotation of embedaddon/rsync/pipe.c, revision 1.1.1.1
1.1 misho 1: /*
2: * Routines used to setup various kinds of inter-process pipes.
3: *
4: * Copyright (C) 1996-2000 Andrew Tridgell
5: * Copyright (C) 1996 Paul Mackerras
6: * Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
7: * Copyright (C) 2004-2009 Wayne Davison
8: *
9: * This program is free software; you can redistribute it and/or modify
10: * it under the terms of the GNU General Public License as published by
11: * the Free Software Foundation; either version 3 of the License, or
12: * (at your option) any later version.
13: *
14: * This program is distributed in the hope that it will be useful,
15: * but WITHOUT ANY WARRANTY; without even the implied warranty of
16: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17: * GNU General Public License for more details.
18: *
19: * You should have received a copy of the GNU General Public License along
20: * with this program; if not, visit the http://fsf.org website.
21: */
22:
23: #include "rsync.h"
24:
25: extern int am_sender;
26: extern int am_server;
27: extern int blocking_io;
28: extern int filesfrom_fd;
29: extern mode_t orig_umask;
30: extern char *logfile_name;
31: extern struct chmod_mode_struct *chmod_modes;
32:
33: /**
34: * Create a child connected to us via its stdin/stdout.
35: *
36: * This is derived from CVS code
37: *
38: * Note that in the child STDIN is set to blocking and STDOUT
39: * is set to non-blocking. This is necessary as rsh relies on stdin being blocking
40: * and ssh relies on stdout being non-blocking
41: *
42: * If blocking_io is set then use blocking io on both fds. That can be
43: * used to cope with badly broken rsh implementations like the one on
44: * Solaris.
45: **/
46: pid_t piped_child(char **command, int *f_in, int *f_out)
47: {
48: pid_t pid;
49: int to_child_pipe[2];
50: int from_child_pipe[2];
51:
52: if (verbose >= 2)
53: print_child_argv("opening connection using:", command);
54:
55: if (fd_pair(to_child_pipe) < 0 || fd_pair(from_child_pipe) < 0) {
56: rsyserr(FERROR, errno, "pipe");
57: exit_cleanup(RERR_IPC);
58: }
59:
60: pid = do_fork();
61: if (pid == -1) {
62: rsyserr(FERROR, errno, "fork");
63: exit_cleanup(RERR_IPC);
64: }
65:
66: if (pid == 0) {
67: if (dup2(to_child_pipe[0], STDIN_FILENO) < 0 ||
68: close(to_child_pipe[1]) < 0 ||
69: close(from_child_pipe[0]) < 0 ||
70: dup2(from_child_pipe[1], STDOUT_FILENO) < 0) {
71: rsyserr(FERROR, errno, "Failed to dup/close");
72: exit_cleanup(RERR_IPC);
73: }
74: if (to_child_pipe[0] != STDIN_FILENO)
75: close(to_child_pipe[0]);
76: if (from_child_pipe[1] != STDOUT_FILENO)
77: close(from_child_pipe[1]);
78: umask(orig_umask);
79: set_blocking(STDIN_FILENO);
80: if (blocking_io > 0)
81: set_blocking(STDOUT_FILENO);
82: execvp(command[0], command);
83: rsyserr(FERROR, errno, "Failed to exec %s", command[0]);
84: exit_cleanup(RERR_IPC);
85: }
86:
87: if (close(from_child_pipe[1]) < 0 || close(to_child_pipe[0]) < 0) {
88: rsyserr(FERROR, errno, "Failed to close");
89: exit_cleanup(RERR_IPC);
90: }
91:
92: *f_in = from_child_pipe[0];
93: *f_out = to_child_pipe[1];
94:
95: return pid;
96: }
97:
98: /* This function forks a child which calls child_main(). First,
99: * however, it has to establish communication paths to and from the
100: * newborn child. It creates two socket pairs -- one for writing to
101: * the child (from the parent) and one for reading from the child
102: * (writing to the parent). Since that's four socket ends, each
103: * process has to close the two ends it doesn't need. The remaining
104: * two socket ends are retained for reading and writing. In the
105: * child, the STDIN and STDOUT file descriptors refer to these
106: * sockets. In the parent, the function arguments f_in and f_out are
107: * set to refer to these sockets. */
108: pid_t local_child(int argc, char **argv, int *f_in, int *f_out,
109: int (*child_main)(int, char*[]))
110: {
111: pid_t pid;
112: int to_child_pipe[2];
113: int from_child_pipe[2];
114:
115: /* The parent process is always the sender for a local rsync. */
116: assert(am_sender);
117:
118: if (fd_pair(to_child_pipe) < 0 ||
119: fd_pair(from_child_pipe) < 0) {
120: rsyserr(FERROR, errno, "pipe");
121: exit_cleanup(RERR_IPC);
122: }
123:
124: pid = do_fork();
125: if (pid == -1) {
126: rsyserr(FERROR, errno, "fork");
127: exit_cleanup(RERR_IPC);
128: }
129:
130: if (pid == 0) {
131: am_sender = 0;
132: am_server = 1;
133: filesfrom_fd = -1;
134: chmod_modes = NULL; /* Let the sending side handle this. */
135:
136: /* Let the client side handle this. */
137: if (logfile_name) {
138: logfile_name = NULL;
139: logfile_close();
140: }
141:
142: if (dup2(to_child_pipe[0], STDIN_FILENO) < 0 ||
143: close(to_child_pipe[1]) < 0 ||
144: close(from_child_pipe[0]) < 0 ||
145: dup2(from_child_pipe[1], STDOUT_FILENO) < 0) {
146: rsyserr(FERROR, errno, "Failed to dup/close");
147: exit_cleanup(RERR_IPC);
148: }
149: if (to_child_pipe[0] != STDIN_FILENO)
150: close(to_child_pipe[0]);
151: if (from_child_pipe[1] != STDOUT_FILENO)
152: close(from_child_pipe[1]);
153: #ifdef ICONV_CONST
154: setup_iconv();
155: #endif
156: child_main(argc, argv);
157: }
158:
159: if (close(from_child_pipe[1]) < 0 ||
160: close(to_child_pipe[0]) < 0) {
161: rsyserr(FERROR, errno, "Failed to close");
162: exit_cleanup(RERR_IPC);
163: }
164:
165: *f_in = from_child_pipe[0];
166: *f_out = to_child_pipe[1];
167:
168: return pid;
169: }
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