summaryrefslogtreecommitdiff
path: root/src/systemd-stdio-bridge/stdio-bridge.c
blob: 9aa17e861cdb288c4a9278ffd89ae4f1f556c581 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <errno.h>
#include <getopt.h>
#include <poll.h>
#include <stddef.h>
#include <string.h>
#include <unistd.h>

#include <systemd/sd-bus.h>
#include <systemd/sd-daemon.h>

#include "sd-bus/bus-internal.h"
#include "sd-bus/bus-util.h"
#include "systemd-basic/build.h"
#include "systemd-basic/log.h"
#include "systemd-basic/util.h"

#define DEFAULT_BUS_PATH "unix:path=/run/dbus/system_bus_socket"

const char *arg_bus_path = DEFAULT_BUS_PATH;

static int help(void) {

        printf("%s [OPTIONS...]\n\n"
               "STDIO or socket-activatable proxy to a given DBus endpoint.\n\n"
               "  -h --help              Show this help\n"
               "     --version           Show package version\n"
               "     --bus-path=PATH     Path to the kernel bus (default: %s)\n",
               program_invocation_short_name, DEFAULT_BUS_PATH);

        return 0;
}

static int parse_argv(int argc, char *argv[]) {

        enum {
                ARG_VERSION = 0x100,
        };

        static const struct option options[] = {
                { "help",            no_argument,       NULL, 'h'     },
                { "bus-path",        required_argument, NULL, 'p'     },
                { NULL,              0,                 NULL, 0       }
        };

        int c;

        assert(argc >= 0);
        assert(argv);

        while ((c = getopt_long(argc, argv, "hsup:", options, NULL)) >= 0) {

                switch (c) {

                case 'h':
                        help();
                        return 0;

                case ARG_VERSION:
                        return version();

                case '?':
                        return -EINVAL;

                case 'p':
                        arg_bus_path = optarg;
                        break;

                default:
                        log_error("Unknown option code %c", c);
                        return -EINVAL;
                }
        }

        return 1;
}

int main(int argc, char *argv[]) {
        _cleanup_(sd_bus_unrefp) sd_bus *a = NULL, *b = NULL;
        sd_id128_t server_id;
        bool is_unix;
        int r, in_fd, out_fd;

        log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
        log_parse_environment();
        log_open();

        r = parse_argv(argc, argv);
        if (r <= 0)
                goto finish;

        r = sd_listen_fds(0);
        if (r == 0) {
                in_fd = STDIN_FILENO;
                out_fd = STDOUT_FILENO;
        } else if (r == 1) {
                in_fd = SD_LISTEN_FDS_START;
                out_fd = SD_LISTEN_FDS_START;
        } else {
                log_error("Illegal number of file descriptors passed\n");
                goto finish;
        }

        is_unix =
                sd_is_socket(in_fd, AF_UNIX, 0, 0) > 0 &&
                sd_is_socket(out_fd, AF_UNIX, 0, 0) > 0;

        r = sd_bus_new(&a);
        if (r < 0) {
                log_error_errno(r, "Failed to allocate bus: %m");
                goto finish;
        }

        r = sd_bus_set_address(a, arg_bus_path);
        if (r < 0) {
                log_error_errno(r, "Failed to set address to connect to: %m");
                goto finish;
        }

        r = sd_bus_negotiate_fds(a, is_unix);
        if (r < 0) {
                log_error_errno(r, "Failed to set FD negotiation: %m");
                goto finish;
        }

        r = sd_bus_start(a);
        if (r < 0) {
                log_error_errno(r, "Failed to start bus client: %m");
                goto finish;
        }

        r = sd_bus_get_bus_id(a, &server_id);
        if (r < 0) {
                log_error_errno(r, "Failed to get server ID: %m");
                goto finish;
        }

        r = sd_bus_new(&b);
        if (r < 0) {
                log_error_errno(r, "Failed to allocate bus: %m");
                goto finish;
        }

        r = sd_bus_set_fd(b, in_fd, out_fd);
        if (r < 0) {
                log_error_errno(r, "Failed to set fds: %m");
                goto finish;
        }

        r = sd_bus_set_server(b, 1, server_id);
        if (r < 0) {
                log_error_errno(r, "Failed to set server mode: %m");
                goto finish;
        }

        r = sd_bus_negotiate_fds(b, is_unix);
        if (r < 0) {
                log_error_errno(r, "Failed to set FD negotiation: %m");
                goto finish;
        }

        r = sd_bus_set_anonymous(b, true);
        if (r < 0) {
                log_error_errno(r, "Failed to set anonymous authentication: %m");
                goto finish;
        }

        r = sd_bus_start(b);
        if (r < 0) {
                log_error_errno(r, "Failed to start bus client: %m");
                goto finish;
        }

        for (;;) {
                _cleanup_(sd_bus_message_unrefp)sd_bus_message *m = NULL;
                int events_a, events_b, fd;
                uint64_t timeout_a, timeout_b, t;
                struct timespec _ts, *ts;

                r = sd_bus_process(a, &m);
                if (r < 0) {
                        log_error_errno(r, "Failed to process bus a: %m");
                        goto finish;
                }

                if (m) {
                        r = sd_bus_send(b, m, NULL);
                        if (r < 0) {
                                log_error_errno(r, "Failed to send message: %m");
                                goto finish;
                        }
                }

                if (r > 0)
                        continue;

                r = sd_bus_process(b, &m);
                if (r < 0) {
                        /* treat 'connection reset by peer' as clean exit condition */
                        if (r == -ECONNRESET)
                                r = 0;

                        goto finish;
                }

                if (m) {
                        r = sd_bus_send(a, m, NULL);
                        if (r < 0) {
                                log_error_errno(r, "Failed to send message: %m");
                                goto finish;
                        }
                }

                if (r > 0)
                        continue;

                fd = sd_bus_get_fd(a);
                if (fd < 0) {
                        r = fd;
                        log_error_errno(r, "Failed to get fd: %m");
                        goto finish;
                }

                events_a = sd_bus_get_events(a);
                if (events_a < 0) {
                        r = events_a;
                        log_error_errno(r, "Failed to get events mask: %m");
                        goto finish;
                }

                r = sd_bus_get_timeout(a, &timeout_a);
                if (r < 0) {
                        log_error_errno(r, "Failed to get timeout: %m");
                        goto finish;
                }

                events_b = sd_bus_get_events(b);
                if (events_b < 0) {
                        r = events_b;
                        log_error_errno(r, "Failed to get events mask: %m");
                        goto finish;
                }

                r = sd_bus_get_timeout(b, &timeout_b);
                if (r < 0) {
                        log_error_errno(r, "Failed to get timeout: %m");
                        goto finish;
                }

                t = timeout_a;
                if (t == (uint64_t) -1 || (timeout_b != (uint64_t) -1 && timeout_b < timeout_a))
                        t = timeout_b;

                if (t == (uint64_t) -1)
                        ts = NULL;
                else {
                        usec_t nw;

                        nw = now(CLOCK_MONOTONIC);
                        if (t > nw)
                                t -= nw;
                        else
                                t = 0;

                        ts = timespec_store(&_ts, t);
                }

                {
                        struct pollfd p[3] = {
                                {.fd = fd,            .events = events_a, },
                                {.fd = STDIN_FILENO,  .events = events_b & POLLIN, },
                                {.fd = STDOUT_FILENO, .events = events_b & POLLOUT, }};

                        r = ppoll(p, ELEMENTSOF(p), ts, NULL);
                }
                if (r < 0) {
                        log_error("ppoll() failed: %m");
                        goto finish;
                }
        }

finish:
        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}