1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3 #include <errno.h>
4 #include <getopt.h>
5 #include <stddef.h>
6 #include <string.h>
7 #include <unistd.h>
8
9 #include "sd-bus.h"
10 #include "sd-daemon.h"
11
12 #include "alloc-util.h"
13 #include "bus-internal.h"
14 #include "bus-util.h"
15 #include "errno-util.h"
16 #include "io-util.h"
17 #include "log.h"
18 #include "main-func.h"
19 #include "util.h"
20 #include "version.h"
21
22 #define DEFAULT_BUS_PATH "unix:path=/run/dbus/system_bus_socket"
23
24 static const char *arg_bus_path = DEFAULT_BUS_PATH;
25 static BusTransport arg_transport = BUS_TRANSPORT_LOCAL;
26 static bool arg_user = false;
27
help(void)28 static int help(void) {
29 printf("%s [OPTIONS...]\n\n"
30 "Forward messages between a pipe or socket and a D-Bus bus.\n\n"
31 " -h --help Show this help\n"
32 " --version Show package version\n"
33 " -p --bus-path=PATH Path to the bus address (default: %s)\n"
34 " --system Connect to system bus\n"
35 " --user Connect to user bus\n"
36 " -M --machine=CONTAINER Name of local container to connect to\n",
37 program_invocation_short_name, DEFAULT_BUS_PATH);
38
39 return 0;
40 }
41
parse_argv(int argc,char * argv[])42 static int parse_argv(int argc, char *argv[]) {
43 enum {
44 ARG_VERSION = 0x100,
45 ARG_MACHINE,
46 ARG_USER,
47 ARG_SYSTEM,
48 };
49
50 static const struct option options[] = {
51 { "help", no_argument, NULL, 'h' },
52 { "version", no_argument, NULL, ARG_VERSION },
53 { "bus-path", required_argument, NULL, 'p' },
54 { "user", no_argument, NULL, ARG_USER },
55 { "system", no_argument, NULL, ARG_SYSTEM },
56 { "machine", required_argument, NULL, 'M' },
57 {},
58 };
59
60 int c;
61
62 assert(argc >= 0);
63 assert(argv);
64
65 while ((c = getopt_long(argc, argv, "hp:M:", options, NULL)) >= 0)
66
67 switch (c) {
68
69 case 'h':
70 return help();
71
72 case ARG_VERSION:
73 return version();
74
75 case ARG_USER:
76 arg_user = true;
77 break;
78
79 case ARG_SYSTEM:
80 arg_user = false;
81 break;
82
83 case 'p':
84 arg_bus_path = optarg;
85 break;
86
87 case 'M':
88 arg_bus_path = optarg;
89 arg_transport = BUS_TRANSPORT_MACHINE;
90 break;
91
92 case '?':
93 return -EINVAL;
94
95 default:
96 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
97 "Unknown option code %c", c);
98 }
99
100 return 1;
101 }
102
run(int argc,char * argv[])103 static int run(int argc, char *argv[]) {
104 _cleanup_(sd_bus_flush_close_unrefp) sd_bus *a = NULL, *b = NULL;
105 sd_id128_t server_id;
106 bool is_unix;
107 int r, in_fd, out_fd;
108
109 log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
110 log_parse_environment();
111 log_open();
112
113 r = parse_argv(argc, argv);
114 if (r <= 0)
115 return r;
116
117 r = sd_listen_fds(0);
118 if (r == 0) {
119 in_fd = STDIN_FILENO;
120 out_fd = STDOUT_FILENO;
121 } else if (r == 1) {
122 in_fd = SD_LISTEN_FDS_START;
123 out_fd = SD_LISTEN_FDS_START;
124 } else
125 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "More than one file descriptor was passed.");
126
127 is_unix =
128 sd_is_socket(in_fd, AF_UNIX, 0, 0) > 0 &&
129 sd_is_socket(out_fd, AF_UNIX, 0, 0) > 0;
130
131 r = sd_bus_new(&a);
132 if (r < 0)
133 return log_error_errno(r, "Failed to allocate bus: %m");
134
135 if (arg_transport == BUS_TRANSPORT_MACHINE)
136 r = bus_set_address_machine(a, arg_user, arg_bus_path);
137 else
138 r = sd_bus_set_address(a, arg_bus_path);
139 if (r < 0)
140 return log_error_errno(r, "Failed to set address to connect to: %m");
141
142 r = sd_bus_negotiate_fds(a, is_unix);
143 if (r < 0)
144 return log_error_errno(r, "Failed to set FD negotiation: %m");
145
146 r = sd_bus_start(a);
147 if (r < 0)
148 return log_error_errno(r, "Failed to start bus client: %m");
149
150 r = sd_bus_get_bus_id(a, &server_id);
151 if (r < 0)
152 return log_error_errno(r, "Failed to get server ID: %m");
153
154 r = sd_bus_new(&b);
155 if (r < 0)
156 return log_error_errno(r, "Failed to allocate bus: %m");
157
158 r = sd_bus_set_fd(b, in_fd, out_fd);
159 if (r < 0)
160 return log_error_errno(r, "Failed to set fds: %m");
161
162 r = sd_bus_set_server(b, 1, server_id);
163 if (r < 0)
164 return log_error_errno(r, "Failed to set server mode: %m");
165
166 r = sd_bus_negotiate_fds(b, is_unix);
167 if (r < 0)
168 return log_error_errno(r, "Failed to set FD negotiation: %m");
169
170 r = sd_bus_set_anonymous(b, true);
171 if (r < 0)
172 return log_error_errno(r, "Failed to set anonymous authentication: %m");
173
174 r = sd_bus_start(b);
175 if (r < 0)
176 return log_error_errno(r, "Failed to start bus client: %m");
177
178 for (;;) {
179 _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
180 int events_a, events_b, fd;
181 usec_t timeout_a, timeout_b, t;
182
183 assert_cc(sizeof(usec_t) == sizeof(uint64_t));
184
185 r = sd_bus_process(a, &m);
186 if (r < 0)
187 return log_error_errno(r, "Failed to process bus a: %m");
188
189 if (m) {
190 r = sd_bus_send(b, m, NULL);
191 if (r < 0)
192 return log_error_errno(r, "Failed to send message: %m");
193 }
194
195 if (r > 0)
196 continue;
197
198 r = sd_bus_process(b, &m);
199 if (r < 0) {
200 /* treat 'connection reset by peer' as clean exit condition */
201 if (ERRNO_IS_DISCONNECT(r))
202 return 0;
203
204 return log_error_errno(r, "Failed to process bus: %m");
205 }
206
207 if (m) {
208 r = sd_bus_send(a, m, NULL);
209 if (r < 0)
210 return log_error_errno(r, "Failed to send message: %m");
211 }
212
213 if (r > 0)
214 continue;
215
216 fd = sd_bus_get_fd(a);
217 if (fd < 0)
218 return log_error_errno(fd, "Failed to get fd: %m");
219
220 events_a = sd_bus_get_events(a);
221 if (events_a < 0)
222 return log_error_errno(events_a, "Failed to get events mask: %m");
223
224 r = sd_bus_get_timeout(a, &timeout_a);
225 if (r < 0)
226 return log_error_errno(r, "Failed to get timeout: %m");
227
228 events_b = sd_bus_get_events(b);
229 if (events_b < 0)
230 return log_error_errno(events_b, "Failed to get events mask: %m");
231
232 r = sd_bus_get_timeout(b, &timeout_b);
233 if (r < 0)
234 return log_error_errno(r, "Failed to get timeout: %m");
235
236 t = usec_sub_unsigned(MIN(timeout_a, timeout_b), now(CLOCK_MONOTONIC));
237
238 struct pollfd p[3] = {
239 { .fd = fd, .events = events_a },
240 { .fd = STDIN_FILENO, .events = events_b & POLLIN },
241 { .fd = STDOUT_FILENO, .events = events_b & POLLOUT },
242 };
243
244 r = ppoll_usec(p, ELEMENTSOF(p), t);
245 if (r < 0)
246 return log_error_errno(r, "ppoll() failed: %m");
247 }
248
249 return 0;
250 }
251
252 DEFINE_MAIN_FUNCTION(run);
253