1 /* $OpenBSD: server.c,v 1.15 2021/11/03 14:42:12 deraadt Exp $ */
2 /*
3 * Copyright (c) 2019 Kristaps Dzonsons <kristaps@bsd.lv>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17 #include <sys/stat.h>
18
19 #include <assert.h>
20 #include <fcntl.h>
21 #include <inttypes.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <unistd.h>
25 #include <err.h>
26
27 #include "extern.h"
28
29 static int
fcntl_nonblock(int fd)30 fcntl_nonblock(int fd)
31 {
32 int fl;
33
34 if ((fl = fcntl(fd, F_GETFL, 0)) == -1)
35 ERR("fcntl: F_GETFL");
36 else if (fcntl(fd, F_SETFL, fl|O_NONBLOCK) == -1)
37 ERR("fcntl: F_SETFL");
38 else
39 return 1;
40
41 return 0;
42 }
43
44 /*
45 * The server (remote) side of the system.
46 * This parses the arguments given it by the remote shell then moves
47 * into receiver or sender mode depending upon those arguments.
48 * Returns exit code 0 on success, 1 on failure, 2 on failure with
49 * incompatible protocols.
50 */
51 int
rsync_server(const struct opts * opts,size_t argc,char * argv[])52 rsync_server(const struct opts *opts, size_t argc, char *argv[])
53 {
54 struct sess sess;
55 int fdin = STDIN_FILENO,
56 fdout = STDOUT_FILENO, rc = 1;
57
58 if (pledge("stdio unix rpath wpath cpath dpath fattr chown getpw unveil",
59 NULL) == -1)
60 err(ERR_IPC, "pledge");
61
62 memset(&sess, 0, sizeof(struct sess));
63 sess.opts = opts;
64
65 /* Begin by making descriptors non-blocking. */
66
67 if (!fcntl_nonblock(fdin) ||
68 !fcntl_nonblock(fdout)) {
69 ERRX1("fcntl_nonblock");
70 goto out;
71 }
72
73 /* Standard rsync preamble, server side. */
74
75 sess.lver = RSYNC_PROTOCOL;
76 sess.seed = arc4random();
77
78 if (!io_read_int(&sess, fdin, &sess.rver)) {
79 ERRX1("io_read_int");
80 goto out;
81 } else if (!io_write_int(&sess, fdout, sess.lver)) {
82 ERRX1("io_write_int");
83 goto out;
84 } else if (!io_write_int(&sess, fdout, sess.seed)) {
85 ERRX1("io_write_int");
86 goto out;
87 }
88
89 sess.mplex_writes = 1;
90
91 if (sess.rver < sess.lver) {
92 ERRX("remote protocol %d is older than our own %d: unsupported",
93 sess.rver, sess.lver);
94 rc = 2;
95 goto out;
96 }
97
98 LOG2("server detected client version %d, server version %d, seed %d",
99 sess.rver, sess.lver, sess.seed);
100
101 if (sess.opts->sender) {
102 LOG2("server starting sender");
103
104 /*
105 * At this time, I always get a period as the first
106 * argument of the command line.
107 * Let's make it a requirement until I figure out when
108 * that differs.
109 * rsync [flags] "." <source> <...>
110 */
111
112 if (strcmp(argv[0], ".")) {
113 ERRX("first argument must be a standalone period");
114 goto out;
115 }
116 argv++;
117 argc--;
118 if (argc == 0) {
119 ERRX("must have arguments");
120 goto out;
121 }
122
123 if (!rsync_sender(&sess, fdin, fdout, argc, argv)) {
124 ERRX1("rsync_sender");
125 goto out;
126 }
127 } else {
128 LOG2("server starting receiver");
129
130 /*
131 * I don't understand why this calling convention
132 * exists, but we must adhere to it.
133 * rsync [flags] "." <destination>
134 */
135
136 if (argc != 2) {
137 ERRX("server receiver mode requires two argument");
138 goto out;
139 } else if (strcmp(argv[0], ".")) {
140 ERRX("first argument must be a standalone period");
141 goto out;
142 }
143
144 if (!rsync_receiver(&sess, fdin, fdout, argv[1])) {
145 ERRX1("rsync_receiver");
146 goto out;
147 }
148 }
149
150 #if 0
151 /* Probably the EOF. */
152 if (io_read_check(&sess, fdin))
153 WARNX("data remains in read pipe");
154 #endif
155
156 rc = 0;
157 out:
158 return rc;
159 }
160