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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later |
d9215cd8 | 2 | * |
55e9959b | 3 | * libudev - interface to udev device information |
d59f11e1 | 4 | * |
4061ab9f KS |
5 | * This library is free software; you can redistribute it and/or |
6 | * modify it under the terms of the GNU Lesser General Public | |
7 | * License as published by the Free Software Foundation; either | |
8 | * version 2.1 of the License, or (at your option) any later version. | |
d59f11e1 KS |
9 | */ |
10 | ||
d59f11e1 | 11 | #include <errno.h> |
cf0fbc49 | 12 | #include <poll.h> |
d59f11e1 | 13 | #include <stddef.h> |
cf0fbc49 | 14 | #include <stdlib.h> |
d59f11e1 | 15 | #include <string.h> |
d59f11e1 | 16 | #include <sys/un.h> |
cf0fbc49 | 17 | #include <unistd.h> |
d59f11e1 | 18 | |
d02c6f54 YW |
19 | #include "sd-event.h" |
20 | ||
b5efdb8a | 21 | #include "alloc-util.h" |
4ff9bc2e | 22 | #include "errno-util.h" |
3ffd4af2 | 23 | #include "fd-util.h" |
f97b34a6 | 24 | #include "format-util.h" |
5cfa2c3d | 25 | #include "io-util.h" |
3ffd4af2 | 26 | #include "socket-util.h" |
7d68eb1b YW |
27 | #include "strxcpyx.h" |
28 | #include "udev-ctrl.h" | |
ef118d00 | 29 | #include "util.h" |
d59f11e1 | 30 | |
540f4669 | 31 | /* wire protocol magic must match */ |
912541b0 | 32 | #define UDEV_CTRL_MAGIC 0xdead1dea |
d59f11e1 | 33 | |
b692a750 | 34 | struct udev_ctrl_msg_wire { |
912541b0 | 35 | char version[16]; |
14cb109d | 36 | unsigned magic; |
912541b0 | 37 | enum udev_ctrl_msg_type type; |
d02c6f54 | 38 | union udev_ctrl_msg_value value; |
d59f11e1 KS |
39 | }; |
40 | ||
41 | struct udev_ctrl { | |
8f71a0d1 | 42 | unsigned n_ref; |
912541b0 | 43 | int sock; |
d02c6f54 | 44 | int sock_connect; |
6421348d | 45 | union sockaddr_union saddr; |
912541b0 | 46 | socklen_t addrlen; |
481f24d1 YW |
47 | bool bound; |
48 | bool cleanup_socket; | |
49 | bool connected; | |
50 | bool maybe_disconnected; | |
d02c6f54 YW |
51 | sd_event *event; |
52 | sd_event_source *event_source; | |
53 | sd_event_source *event_source_connect; | |
54 | udev_ctrl_handler_t callback; | |
55 | void *userdata; | |
d59f11e1 KS |
56 | }; |
57 | ||
100bc5bf YW |
58 | int udev_ctrl_new_from_fd(struct udev_ctrl **ret, int fd) { |
59 | _cleanup_close_ int sock = -1; | |
912541b0 KS |
60 | struct udev_ctrl *uctrl; |
61 | ||
100bc5bf | 62 | assert(ret); |
912541b0 KS |
63 | |
64 | if (fd < 0) { | |
100bc5bf YW |
65 | sock = socket(AF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0); |
66 | if (sock < 0) | |
67 | return log_error_errno(errno, "Failed to create socket: %m"); | |
912541b0 | 68 | } |
25568304 | 69 | |
100bc5bf YW |
70 | uctrl = new(struct udev_ctrl, 1); |
71 | if (!uctrl) | |
72 | return -ENOMEM; | |
73 | ||
74 | *uctrl = (struct udev_ctrl) { | |
75 | .n_ref = 1, | |
76 | .sock = fd >= 0 ? fd : TAKE_FD(sock), | |
2f5b282a | 77 | .sock_connect = -1, |
100bc5bf YW |
78 | .bound = fd >= 0, |
79 | }; | |
80 | ||
44ed5214 LP |
81 | uctrl->saddr.un = (struct sockaddr_un) { |
82 | .sun_family = AF_UNIX, | |
83 | .sun_path = "/run/udev/control", | |
84 | }; | |
85 | ||
fc2fffe7 | 86 | uctrl->addrlen = SOCKADDR_UN_LEN(uctrl->saddr.un); |
fc1de713 | 87 | |
100bc5bf YW |
88 | *ret = TAKE_PTR(uctrl); |
89 | return 0; | |
d59f11e1 KS |
90 | } |
91 | ||
9ec6e95b | 92 | int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl) { |
53bba2fb | 93 | int r; |
912541b0 | 94 | |
53bba2fb | 95 | assert(uctrl); |
912541b0 | 96 | |
53bba2fb YW |
97 | if (uctrl->bound) |
98 | return 0; | |
912541b0 | 99 | |
53bba2fb YW |
100 | r = bind(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen); |
101 | if (r < 0 && errno == EADDRINUSE) { | |
102 | (void) sockaddr_un_unlink(&uctrl->saddr.un); | |
103 | r = bind(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen); | |
912541b0 | 104 | } |
53bba2fb YW |
105 | |
106 | if (r < 0) | |
107 | return log_error_errno(errno, "Failed to bind udev control socket: %m"); | |
108 | ||
109 | if (listen(uctrl->sock, 0) < 0) | |
110 | return log_error_errno(errno, "Failed to listen udev control socket: %m"); | |
111 | ||
112 | uctrl->bound = true; | |
113 | uctrl->cleanup_socket = true; | |
114 | ||
912541b0 | 115 | return 0; |
d59f11e1 KS |
116 | } |
117 | ||
d02c6f54 YW |
118 | static void udev_ctrl_disconnect(struct udev_ctrl *uctrl) { |
119 | if (!uctrl) | |
120 | return; | |
121 | ||
122 | uctrl->event_source_connect = sd_event_source_unref(uctrl->event_source_connect); | |
123 | uctrl->sock_connect = safe_close(uctrl->sock_connect); | |
124 | } | |
125 | ||
8f71a0d1 YW |
126 | static struct udev_ctrl *udev_ctrl_free(struct udev_ctrl *uctrl) { |
127 | assert(uctrl); | |
35927d13 | 128 | |
d02c6f54 YW |
129 | udev_ctrl_disconnect(uctrl); |
130 | ||
131 | sd_event_source_unref(uctrl->event_source); | |
8f71a0d1 | 132 | safe_close(uctrl->sock); |
d02c6f54 YW |
133 | |
134 | sd_event_unref(uctrl->event); | |
8f71a0d1 | 135 | return mfree(uctrl); |
d59f11e1 KS |
136 | } |
137 | ||
d02c6f54 | 138 | DEFINE_TRIVIAL_REF_UNREF_FUNC(struct udev_ctrl, udev_ctrl, udev_ctrl_free); |
d59f11e1 | 139 | |
9ec6e95b | 140 | int udev_ctrl_cleanup(struct udev_ctrl *uctrl) { |
9315f853 | 141 | if (!uctrl) |
912541b0 KS |
142 | return 0; |
143 | if (uctrl->cleanup_socket) | |
155b6876 | 144 | sockaddr_un_unlink(&uctrl->saddr.un); |
912541b0 | 145 | return 0; |
1f5a5100 KS |
146 | } |
147 | ||
d02c6f54 YW |
148 | int udev_ctrl_attach_event(struct udev_ctrl *uctrl, sd_event *event) { |
149 | int r; | |
150 | ||
151 | assert_return(uctrl, -EINVAL); | |
152 | assert_return(!uctrl->event, -EBUSY); | |
153 | ||
154 | if (event) | |
155 | uctrl->event = sd_event_ref(event); | |
156 | else { | |
157 | r = sd_event_default(&uctrl->event); | |
158 | if (r < 0) | |
159 | return r; | |
160 | } | |
161 | ||
162 | return 0; | |
d59f11e1 KS |
163 | } |
164 | ||
d02c6f54 YW |
165 | sd_event_source *udev_ctrl_get_event_source(struct udev_ctrl *uctrl) { |
166 | assert(uctrl); | |
167 | ||
168 | return uctrl->event_source; | |
169 | } | |
170 | ||
171 | static void udev_ctrl_disconnect_and_listen_again(struct udev_ctrl *uctrl) { | |
172 | udev_ctrl_disconnect(uctrl); | |
173 | udev_ctrl_unref(uctrl); | |
174 | (void) sd_event_source_set_enabled(uctrl->event_source, SD_EVENT_ON); | |
175 | } | |
176 | ||
177 | DEFINE_TRIVIAL_CLEANUP_FUNC(struct udev_ctrl *, udev_ctrl_disconnect_and_listen_again); | |
178 | ||
179 | static int udev_ctrl_connection_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
180 | _cleanup_(udev_ctrl_disconnect_and_listen_againp) struct udev_ctrl *uctrl = NULL; | |
181 | struct udev_ctrl_msg_wire msg_wire; | |
182 | struct iovec iov = IOVEC_MAKE(&msg_wire, sizeof(struct udev_ctrl_msg_wire)); | |
fb29cdbe | 183 | CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control; |
d02c6f54 YW |
184 | struct msghdr smsg = { |
185 | .msg_iov = &iov, | |
186 | .msg_iovlen = 1, | |
fb29cdbe LP |
187 | .msg_control = &control, |
188 | .msg_controllen = sizeof(control), | |
d02c6f54 YW |
189 | }; |
190 | struct cmsghdr *cmsg; | |
191 | struct ucred *cred; | |
192 | ssize_t size; | |
193 | ||
194 | assert(userdata); | |
195 | ||
196 | /* When UDEV_CTRL_EXIT is received, manager unref udev_ctrl object. | |
197 | * To avoid the object freed, let's increment the refcount. */ | |
198 | uctrl = udev_ctrl_ref(userdata); | |
199 | ||
200 | size = next_datagram_size_fd(fd); | |
201 | if (size < 0) | |
202 | return log_error_errno(size, "Failed to get size of message: %m"); | |
203 | if (size == 0) | |
204 | return 0; /* Client disconnects? */ | |
205 | ||
3691bcf3 LP |
206 | size = recvmsg_safe(fd, &smsg, 0); |
207 | if (size == -EINTR) | |
d02c6f54 | 208 | return 0; |
3691bcf3 LP |
209 | if (size < 0) |
210 | return log_error_errno(size, "Failed to receive ctrl message: %m"); | |
d02c6f54 YW |
211 | |
212 | cmsg_close_all(&smsg); | |
213 | ||
214 | cmsg = CMSG_FIRSTHDR(&smsg); | |
215 | ||
216 | if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
217 | log_error("No sender credentials received, ignoring message"); | |
218 | return 0; | |
219 | } | |
220 | ||
221 | cred = (struct ucred *) CMSG_DATA(cmsg); | |
222 | ||
223 | if (cred->uid != 0) { | |
224 | log_error("Invalid sender uid "UID_FMT", ignoring message", cred->uid); | |
225 | return 0; | |
226 | } | |
227 | ||
228 | if (msg_wire.magic != UDEV_CTRL_MAGIC) { | |
229 | log_error("Message magic 0x%08x doesn't match, ignoring message", msg_wire.magic); | |
230 | return 0; | |
231 | } | |
232 | ||
78467aeb YW |
233 | if (msg_wire.type == _UDEV_CTRL_END_MESSAGES) |
234 | return 0; | |
235 | ||
d02c6f54 YW |
236 | if (uctrl->callback) |
237 | (void) uctrl->callback(uctrl, msg_wire.type, &msg_wire.value, uctrl->userdata); | |
238 | ||
78467aeb YW |
239 | /* Do not disconnect and wait for next message. */ |
240 | uctrl = udev_ctrl_unref(uctrl); | |
d02c6f54 YW |
241 | return 0; |
242 | } | |
243 | ||
244 | static int udev_ctrl_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
245 | struct udev_ctrl *uctrl = userdata; | |
246 | _cleanup_close_ int sock = -1; | |
247 | struct ucred ucred; | |
eff05270 | 248 | int r; |
912541b0 | 249 | |
d02c6f54 | 250 | assert(uctrl); |
912541b0 | 251 | |
d02c6f54 YW |
252 | sock = accept4(fd, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK); |
253 | if (sock < 0) { | |
4ff9bc2e LP |
254 | if (ERRNO_IS_ACCEPT_AGAIN(errno)) |
255 | return 0; | |
256 | ||
257 | return log_error_errno(errno, "Failed to accept ctrl connection: %m"); | |
912541b0 KS |
258 | } |
259 | ||
260 | /* check peer credential of connection */ | |
d02c6f54 | 261 | r = getpeercred(sock, &ucred); |
eff05270 | 262 | if (r < 0) { |
572909a3 | 263 | log_error_errno(r, "Failed to receive credentials of ctrl connection: %m"); |
d02c6f54 | 264 | return 0; |
912541b0 | 265 | } |
d02c6f54 | 266 | |
912541b0 | 267 | if (ucred.uid > 0) { |
d02c6f54 YW |
268 | log_error("Invalid sender uid "UID_FMT", closing connection", ucred.uid); |
269 | return 0; | |
912541b0 KS |
270 | } |
271 | ||
272 | /* enable receiving of the sender credentials in the messages */ | |
d02c6f54 | 273 | r = setsockopt_int(sock, SOL_SOCKET, SO_PASSCRED, true); |
4bbdff75 | 274 | if (r < 0) |
d02c6f54 | 275 | log_warning_errno(r, "Failed to set SO_PASSCRED, ignoring: %m"); |
4bbdff75 | 276 | |
d02c6f54 YW |
277 | r = sd_event_add_io(uctrl->event, &uctrl->event_source_connect, sock, EPOLLIN, udev_ctrl_connection_event_handler, uctrl); |
278 | if (r < 0) { | |
279 | log_error_errno(r, "Failed to create event source for udev control connection: %m"); | |
280 | return 0; | |
281 | } | |
282 | ||
283 | (void) sd_event_source_set_description(uctrl->event_source_connect, "udev-ctrl-connection"); | |
ff2c503d | 284 | |
d02c6f54 YW |
285 | /* Do not accept multiple connection. */ |
286 | (void) sd_event_source_set_enabled(uctrl->event_source, SD_EVENT_OFF); | |
35927d13 | 287 | |
d02c6f54 YW |
288 | uctrl->sock_connect = TAKE_FD(sock); |
289 | return 0; | |
ff2c503d KS |
290 | } |
291 | ||
d02c6f54 YW |
292 | int udev_ctrl_start(struct udev_ctrl *uctrl, udev_ctrl_handler_t callback, void *userdata) { |
293 | int r; | |
294 | ||
295 | assert(uctrl); | |
296 | ||
297 | if (!uctrl->event) { | |
298 | r = udev_ctrl_attach_event(uctrl, NULL); | |
299 | if (r < 0) | |
300 | return r; | |
301 | } | |
302 | ||
303 | r = udev_ctrl_enable_receiving(uctrl); | |
304 | if (r < 0) | |
305 | return r; | |
306 | ||
307 | uctrl->callback = callback; | |
308 | uctrl->userdata = userdata; | |
309 | ||
310 | r = sd_event_add_io(uctrl->event, &uctrl->event_source, uctrl->sock, EPOLLIN, udev_ctrl_event_handler, uctrl); | |
311 | if (r < 0) | |
312 | return r; | |
313 | ||
314 | (void) sd_event_source_set_description(uctrl->event_source, "udev-ctrl"); | |
315 | ||
316 | return 0; | |
317 | } | |
8f71a0d1 | 318 | |
78467aeb | 319 | int udev_ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf) { |
b9da6a09 ZJS |
320 | struct udev_ctrl_msg_wire ctrl_msg_wire = { |
321 | .version = "udev-" STRINGIFY(PROJECT_VERSION), | |
322 | .magic = UDEV_CTRL_MAGIC, | |
323 | .type = type, | |
324 | }; | |
912541b0 | 325 | |
78467aeb YW |
326 | if (uctrl->maybe_disconnected) |
327 | return -ENOANO; /* to distinguish this from other errors. */ | |
328 | ||
9315f853 | 329 | if (buf) |
d02c6f54 | 330 | strscpy(ctrl_msg_wire.value.buf, sizeof(ctrl_msg_wire.value.buf), buf); |
912541b0 | 331 | else |
d02c6f54 | 332 | ctrl_msg_wire.value.intval = intval; |
912541b0 KS |
333 | |
334 | if (!uctrl->connected) { | |
b9da6a09 ZJS |
335 | if (connect(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen) < 0) |
336 | return -errno; | |
912541b0 KS |
337 | uctrl->connected = true; |
338 | } | |
78467aeb | 339 | |
b9da6a09 ZJS |
340 | if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) |
341 | return -errno; | |
912541b0 | 342 | |
78467aeb YW |
343 | if (type == UDEV_CTRL_EXIT) |
344 | uctrl->maybe_disconnected = true; | |
d59f11e1 | 345 | |
78467aeb | 346 | return 0; |
ff2c503d KS |
347 | } |
348 | ||
78467aeb YW |
349 | int udev_ctrl_wait(struct udev_ctrl *uctrl, usec_t timeout) { |
350 | _cleanup_(sd_event_source_unrefp) sd_event_source *source_io = NULL, *source_timeout = NULL; | |
351 | int r; | |
d59f11e1 | 352 | |
78467aeb | 353 | assert(uctrl); |
d59f11e1 | 354 | |
78467aeb YW |
355 | if (uctrl->sock < 0) |
356 | return 0; | |
357 | if (!uctrl->connected) | |
358 | return 0; | |
d59f11e1 | 359 | |
78467aeb YW |
360 | if (!uctrl->maybe_disconnected) { |
361 | r = udev_ctrl_send(uctrl, _UDEV_CTRL_END_MESSAGES, 0, NULL); | |
362 | if (r < 0) | |
363 | return r; | |
364 | } | |
d59f11e1 | 365 | |
78467aeb YW |
366 | if (timeout == 0) |
367 | return 0; | |
368 | ||
369 | if (!uctrl->event) { | |
370 | r = udev_ctrl_attach_event(uctrl, NULL); | |
371 | if (r < 0) | |
372 | return r; | |
373 | } | |
374 | ||
cbda8bd5 | 375 | r = sd_event_add_io(uctrl->event, &source_io, uctrl->sock, EPOLLIN, NULL, INT_TO_PTR(0)); |
78467aeb YW |
376 | if (r < 0) |
377 | return r; | |
378 | ||
60ccab09 | 379 | (void) sd_event_source_set_description(source_io, "udev-ctrl-wait-io"); |
78467aeb YW |
380 | |
381 | if (timeout != USEC_INFINITY) { | |
39cf0351 LP |
382 | r = sd_event_add_time_relative( |
383 | uctrl->event, &source_timeout, clock_boottime_or_monotonic(), | |
384 | timeout, | |
385 | 0, NULL, INT_TO_PTR(-ETIMEDOUT)); | |
78467aeb YW |
386 | if (r < 0) |
387 | return r; | |
388 | ||
f6e8ba81 | 389 | (void) sd_event_source_set_description(source_timeout, "udev-ctrl-wait-timeout"); |
78467aeb | 390 | } |
d59f11e1 | 391 | |
78467aeb | 392 | return sd_event_loop(uctrl->event); |
bb38678e | 393 | } |