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88a6477e KS |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2008-2012 Kay Sievers <kay@vrfy.org> | |
5 | ||
6 | systemd is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU Lesser General Public License as published by | |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | systemd is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public License | |
17 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
18 | ***/ | |
ba6929f6 | 19 | |
ba6929f6 KS |
20 | #include <stdio.h> |
21 | #include <stdlib.h> | |
22 | #include <stddef.h> | |
23 | #include <unistd.h> | |
24 | #include <errno.h> | |
25 | #include <string.h> | |
26 | #include <dirent.h> | |
e14bdd88 | 27 | #include <sys/poll.h> |
ba6929f6 KS |
28 | #include <sys/stat.h> |
29 | #include <sys/socket.h> | |
30 | #include <sys/un.h> | |
e14bdd88 | 31 | #include <arpa/inet.h> |
1c7047ea | 32 | #include <linux/netlink.h> |
e14bdd88 | 33 | #include <linux/filter.h> |
ba6929f6 KS |
34 | |
35 | #include "libudev.h" | |
36 | #include "libudev-private.h" | |
b49d9b50 | 37 | #include "socket-util.h" |
df32a1ca | 38 | #include "missing.h" |
ba6929f6 | 39 | |
ce1d6d7f KS |
40 | /** |
41 | * SECTION:libudev-monitor | |
42 | * @short_description: device event source | |
43 | * | |
44 | * Connects to a device event source. | |
45 | */ | |
46 | ||
ce1d6d7f KS |
47 | /** |
48 | * udev_monitor: | |
49 | * | |
50579295 | 50 | * Opaque object handling an event source. |
ce1d6d7f | 51 | */ |
ba6929f6 | 52 | struct udev_monitor { |
912541b0 KS |
53 | struct udev *udev; |
54 | int refcount; | |
55 | int sock; | |
b49d9b50 KS |
56 | union sockaddr_union snl; |
57 | union sockaddr_union snl_trusted_sender; | |
58 | union sockaddr_union snl_destination; | |
912541b0 KS |
59 | socklen_t addrlen; |
60 | struct udev_list filter_subsystem_list; | |
61 | struct udev_list filter_tag_list; | |
62 | bool bound; | |
ba6929f6 KS |
63 | }; |
64 | ||
f2b93744 | 65 | enum udev_monitor_netlink_group { |
912541b0 KS |
66 | UDEV_MONITOR_NONE, |
67 | UDEV_MONITOR_KERNEL, | |
68 | UDEV_MONITOR_UDEV, | |
f2b93744 KS |
69 | }; |
70 | ||
912541b0 | 71 | #define UDEV_MONITOR_MAGIC 0xfeedcafe |
e14bdd88 | 72 | struct udev_monitor_netlink_header { |
912541b0 KS |
73 | /* "libudev" prefix to distinguish libudev and kernel messages */ |
74 | char prefix[8]; | |
75 | /* | |
76 | * magic to protect against daemon <-> library message format mismatch | |
77 | * used in the kernel from socket filter rules; needs to be stored in network order | |
78 | */ | |
79 | unsigned int magic; | |
80 | /* total length of header structure known to the sender */ | |
81 | unsigned int header_size; | |
82 | /* properties string buffer */ | |
83 | unsigned int properties_off; | |
84 | unsigned int properties_len; | |
85 | /* | |
86 | * hashes of primary device properties strings, to let libudev subscribers | |
87 | * use in-kernel socket filters; values need to be stored in network order | |
88 | */ | |
89 | unsigned int filter_subsystem_hash; | |
90 | unsigned int filter_devtype_hash; | |
91 | unsigned int filter_tag_bloom_hi; | |
92 | unsigned int filter_tag_bloom_lo; | |
e14bdd88 KS |
93 | }; |
94 | ||
95 | static struct udev_monitor *udev_monitor_new(struct udev *udev) | |
96 | { | |
912541b0 KS |
97 | struct udev_monitor *udev_monitor; |
98 | ||
955d98c9 | 99 | udev_monitor = new0(struct udev_monitor, 1); |
912541b0 KS |
100 | if (udev_monitor == NULL) |
101 | return NULL; | |
102 | udev_monitor->refcount = 1; | |
103 | udev_monitor->udev = udev; | |
104 | udev_list_init(udev, &udev_monitor->filter_subsystem_list, false); | |
105 | udev_list_init(udev, &udev_monitor->filter_tag_list, true); | |
106 | return udev_monitor; | |
e14bdd88 KS |
107 | } |
108 | ||
df32a1ca KS |
109 | /* we consider udev running when /dev is on devtmpfs */ |
110 | static bool udev_has_devtmpfs(struct udev *udev) { | |
111 | struct file_handle *h; | |
112 | int mount_id; | |
113 | _cleanup_fclose_ FILE *f = NULL; | |
114 | char line[LINE_MAX], *e; | |
115 | int r; | |
116 | ||
117 | h = alloca(MAX_HANDLE_SZ); | |
e8a3b2dc | 118 | h->handle_bytes = MAX_HANDLE_SZ; |
df32a1ca KS |
119 | r = name_to_handle_at(AT_FDCWD, "/dev", h, &mount_id, 0); |
120 | if (r < 0) | |
121 | return false; | |
122 | ||
123 | ||
124 | f = fopen("/proc/self/mountinfo", "re"); | |
125 | if (!f) | |
126 | return false; | |
127 | ||
128 | FOREACH_LINE(line, f, return false) { | |
df32a1ca KS |
129 | int mid; |
130 | ||
131 | if (sscanf(line, "%i", &mid) != 1) | |
132 | continue; | |
133 | ||
134 | if (mid != mount_id) | |
135 | continue; | |
136 | ||
137 | e = strstr(line, " - "); | |
138 | if (!e) | |
139 | continue; | |
140 | ||
141 | /* accept any name that starts with the currently expected type */ | |
142 | if (startswith(e + 3, "devtmpfs")) | |
143 | return true; | |
144 | } | |
145 | ||
146 | return false; | |
147 | } | |
148 | ||
149 | /* we consider udev running when we have running udev service */ | |
150 | static bool udev_has_service(struct udev *udev) { | |
151 | struct udev_queue *queue; | |
152 | bool active; | |
153 | ||
154 | queue = udev_queue_new(udev); | |
155 | if (!queue) | |
156 | return false; | |
157 | ||
158 | active = udev_queue_get_udev_is_active(queue); | |
159 | udev_queue_unref(queue); | |
160 | ||
161 | return active; | |
162 | } | |
163 | ||
7459bcdc | 164 | struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) |
1c7047ea | 165 | { |
912541b0 KS |
166 | struct udev_monitor *udev_monitor; |
167 | unsigned int group; | |
168 | ||
169 | if (udev == NULL) | |
170 | return NULL; | |
171 | ||
172 | if (name == NULL) | |
173 | group = UDEV_MONITOR_NONE; | |
e8a3b2dc KS |
174 | else if (streq(name, "udev")) { |
175 | /* | |
176 | * We do not support subscribing to uevents if no instance of | |
177 | * udev is running. Uevents would otherwise broadcast the | |
178 | * processing data of the host into containers, which is not | |
179 | * desired. | |
180 | * | |
181 | * Containers will currently not get any udev uevents, until | |
182 | * a supporting infrastructure is available. | |
183 | * | |
184 | * We do not set a netlink multicast group here, so the socket | |
185 | * will not receive any messages. | |
186 | */ | |
187 | if (!udev_has_service(udev) && !udev_has_devtmpfs(udev)) { | |
188 | udev_dbg(udev, "the udev service seems not to be active, disable the monitor\n"); | |
189 | group = UDEV_MONITOR_NONE; | |
190 | } else | |
191 | group = UDEV_MONITOR_UDEV; | |
192 | } else if (streq(name, "kernel")) | |
912541b0 KS |
193 | group = UDEV_MONITOR_KERNEL; |
194 | else | |
195 | return NULL; | |
196 | ||
197 | udev_monitor = udev_monitor_new(udev); | |
198 | if (udev_monitor == NULL) | |
199 | return NULL; | |
200 | ||
201 | if (fd < 0) { | |
202 | udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); | |
203 | if (udev_monitor->sock == -1) { | |
c8f8394a | 204 | udev_err(udev, "error getting socket: %m\n"); |
912541b0 KS |
205 | free(udev_monitor); |
206 | return NULL; | |
207 | } | |
208 | } else { | |
209 | udev_monitor->bound = true; | |
210 | udev_monitor->sock = fd; | |
211 | } | |
212 | ||
b49d9b50 KS |
213 | udev_monitor->snl.nl.nl_family = AF_NETLINK; |
214 | udev_monitor->snl.nl.nl_groups = group; | |
912541b0 KS |
215 | |
216 | /* default destination for sending */ | |
b49d9b50 KS |
217 | udev_monitor->snl_destination.nl.nl_family = AF_NETLINK; |
218 | udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV; | |
912541b0 | 219 | |
912541b0 | 220 | return udev_monitor; |
1c7047ea KS |
221 | } |
222 | ||
7459bcdc KS |
223 | /** |
224 | * udev_monitor_new_from_netlink: | |
225 | * @udev: udev library context | |
226 | * @name: name of event source | |
227 | * | |
228 | * Create new udev monitor and connect to a specified event | |
229 | * source. Valid sources identifiers are "udev" and "kernel". | |
230 | * | |
231 | * Applications should usually not connect directly to the | |
232 | * "kernel" events, because the devices might not be useable | |
233 | * at that time, before udev has configured them, and created | |
50579295 KS |
234 | * device nodes. Accessing devices at the same time as udev, |
235 | * might result in unpredictable behavior. The "udev" events | |
236 | * are sent out after udev has finished its event processing, | |
237 | * all rules have been processed, and needed device nodes are | |
238 | * created. | |
7459bcdc KS |
239 | * |
240 | * The initial refcount is 1, and needs to be decremented to | |
241 | * release the resources of the udev monitor. | |
242 | * | |
243 | * Returns: a new udev monitor, or #NULL, in case of an error | |
244 | **/ | |
54cf0b7f | 245 | _public_ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) |
7459bcdc | 246 | { |
912541b0 | 247 | return udev_monitor_new_from_netlink_fd(udev, name, -1); |
7459bcdc KS |
248 | } |
249 | ||
e14bdd88 | 250 | static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i, |
912541b0 | 251 | unsigned short code, unsigned int data) |
e14bdd88 | 252 | { |
912541b0 | 253 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 254 | |
912541b0 KS |
255 | ins->code = code; |
256 | ins->k = data; | |
257 | (*i)++; | |
e14bdd88 KS |
258 | } |
259 | ||
260 | static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i, | |
912541b0 KS |
261 | unsigned short code, unsigned int data, |
262 | unsigned short jt, unsigned short jf) | |
e14bdd88 | 263 | { |
912541b0 | 264 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 265 | |
912541b0 KS |
266 | ins->code = code; |
267 | ins->jt = jt; | |
268 | ins->jf = jf; | |
269 | ins->k = data; | |
270 | (*i)++; | |
e14bdd88 KS |
271 | } |
272 | ||
ce1d6d7f KS |
273 | /** |
274 | * udev_monitor_filter_update: | |
275 | * @udev_monitor: monitor | |
276 | * | |
50579295 KS |
277 | * Update the installed socket filter. This is only needed, |
278 | * if the filter was removed or changed. | |
ce1d6d7f KS |
279 | * |
280 | * Returns: 0 on success, otherwise a negative error value. | |
281 | */ | |
54cf0b7f | 282 | _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor) |
e14bdd88 | 283 | { |
912541b0 KS |
284 | struct sock_filter ins[512]; |
285 | struct sock_fprog filter; | |
286 | unsigned int i; | |
287 | struct udev_list_entry *list_entry; | |
288 | int err; | |
289 | ||
290 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL && | |
291 | udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) | |
292 | return 0; | |
293 | ||
29804cc1 | 294 | memzero(ins, sizeof(ins)); |
912541b0 KS |
295 | i = 0; |
296 | ||
297 | /* load magic in A */ | |
298 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic)); | |
299 | /* jump if magic matches */ | |
300 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); | |
301 | /* wrong magic, pass packet */ | |
302 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
303 | ||
304 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) { | |
305 | int tag_matches; | |
306 | ||
307 | /* count tag matches, to calculate end of tag match block */ | |
308 | tag_matches = 0; | |
309 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) | |
310 | tag_matches++; | |
311 | ||
312 | /* add all tags matches */ | |
313 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
314 | uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
315 | uint32_t tag_bloom_hi = tag_bloom_bits >> 32; | |
316 | uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; | |
317 | ||
318 | /* load device bloom bits in A */ | |
319 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi)); | |
320 | /* clear bits (tag bits & bloom bits) */ | |
321 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); | |
322 | /* jump to next tag if it does not match */ | |
323 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); | |
324 | ||
325 | /* load device bloom bits in A */ | |
326 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo)); | |
327 | /* clear bits (tag bits & bloom bits) */ | |
328 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); | |
329 | /* jump behind end of tag match block if tag matches */ | |
330 | tag_matches--; | |
331 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); | |
332 | } | |
333 | ||
334 | /* nothing matched, drop packet */ | |
335 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
336 | } | |
337 | ||
338 | /* add all subsystem matches */ | |
339 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) { | |
340 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
341 | unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry)); | |
342 | ||
343 | /* load device subsystem value in A */ | |
344 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash)); | |
345 | if (udev_list_entry_get_value(list_entry) == NULL) { | |
346 | /* jump if subsystem does not match */ | |
347 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
348 | } else { | |
349 | /* jump if subsystem does not match */ | |
350 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); | |
351 | ||
352 | /* load device devtype value in A */ | |
353 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash)); | |
354 | /* jump if value does not match */ | |
355 | hash = util_string_hash32(udev_list_entry_get_value(list_entry)); | |
356 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
357 | } | |
358 | ||
359 | /* matched, pass packet */ | |
360 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
361 | ||
8fef0ff2 | 362 | if (i+1 >= ELEMENTSOF(ins)) |
994e0234 | 363 | return -E2BIG; |
912541b0 KS |
364 | } |
365 | ||
366 | /* nothing matched, drop packet */ | |
367 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
368 | } | |
369 | ||
370 | /* matched, pass packet */ | |
371 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
372 | ||
373 | /* install filter */ | |
29804cc1 | 374 | memzero(&filter, sizeof(filter)); |
912541b0 KS |
375 | filter.len = i; |
376 | filter.filter = ins; | |
377 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
994e0234 | 378 | return err < 0 ? -errno : 0; |
e14bdd88 KS |
379 | } |
380 | ||
1e03b754 KS |
381 | int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
382 | { | |
b49d9b50 | 383 | udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid; |
912541b0 | 384 | return 0; |
1e03b754 | 385 | } |
ce1d6d7f KS |
386 | /** |
387 | * udev_monitor_enable_receiving: | |
388 | * @udev_monitor: the monitor which should receive events | |
389 | * | |
390 | * Binds the @udev_monitor socket to the event source. | |
391 | * | |
392 | * Returns: 0 on success, otherwise a negative error value. | |
393 | */ | |
54cf0b7f | 394 | _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
d59f11e1 | 395 | { |
912541b0 KS |
396 | int err = 0; |
397 | const int on = 1; | |
398 | ||
2d13da88 KS |
399 | udev_monitor_filter_update(udev_monitor); |
400 | ||
401 | if (!udev_monitor->bound) { | |
402 | err = bind(udev_monitor->sock, | |
b49d9b50 | 403 | &udev_monitor->snl.sa, sizeof(struct sockaddr_nl)); |
2d13da88 KS |
404 | if (err == 0) |
405 | udev_monitor->bound = true; | |
912541b0 KS |
406 | } |
407 | ||
2d13da88 | 408 | if (err >= 0) { |
b49d9b50 | 409 | union sockaddr_union snl; |
2d13da88 KS |
410 | socklen_t addrlen; |
411 | ||
412 | /* | |
413 | * get the address the kernel has assigned us | |
414 | * it is usually, but not necessarily the pid | |
415 | */ | |
416 | addrlen = sizeof(struct sockaddr_nl); | |
b49d9b50 | 417 | err = getsockname(udev_monitor->sock, &snl.sa, &addrlen); |
2d13da88 | 418 | if (err == 0) |
b49d9b50 | 419 | udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid; |
2d13da88 | 420 | } else { |
c8f8394a | 421 | udev_err(udev_monitor->udev, "bind failed: %m\n"); |
994e0234 | 422 | return -errno; |
912541b0 KS |
423 | } |
424 | ||
425 | /* enable receiving of sender credentials */ | |
426 | setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); | |
427 | return 0; | |
ba6929f6 KS |
428 | } |
429 | ||
f712894d KS |
430 | /** |
431 | * udev_monitor_set_receive_buffer_size: | |
432 | * @udev_monitor: the monitor which should receive events | |
433 | * @size: the size in bytes | |
434 | * | |
435 | * Set the size of the kernel socket buffer. This call needs the | |
436 | * appropriate privileges to succeed. | |
437 | * | |
438 | * Returns: 0 on success, otherwise -1 on error. | |
439 | */ | |
54cf0b7f | 440 | _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
cb25a958 | 441 | { |
912541b0 | 442 | if (udev_monitor == NULL) |
994e0234 | 443 | return -EINVAL; |
912541b0 | 444 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)); |
cb25a958 KS |
445 | } |
446 | ||
1e03b754 KS |
447 | int udev_monitor_disconnect(struct udev_monitor *udev_monitor) |
448 | { | |
912541b0 | 449 | int err; |
1e03b754 | 450 | |
912541b0 KS |
451 | err = close(udev_monitor->sock); |
452 | udev_monitor->sock = -1; | |
994e0234 | 453 | return err < 0 ? -errno : 0; |
1e03b754 KS |
454 | } |
455 | ||
7d8787b3 KS |
456 | /** |
457 | * udev_monitor_ref: | |
458 | * @udev_monitor: udev monitor | |
459 | * | |
460 | * Take a reference of a udev monitor. | |
461 | * | |
462 | * Returns: the passed udev monitor | |
463 | **/ | |
54cf0b7f | 464 | _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor) |
ba6929f6 | 465 | { |
912541b0 KS |
466 | if (udev_monitor == NULL) |
467 | return NULL; | |
468 | udev_monitor->refcount++; | |
469 | return udev_monitor; | |
ba6929f6 KS |
470 | } |
471 | ||
7d8787b3 KS |
472 | /** |
473 | * udev_monitor_unref: | |
474 | * @udev_monitor: udev monitor | |
475 | * | |
ff109b8d | 476 | * Drop a reference of a udev monitor. If the refcount reaches zero, |
be7de409 | 477 | * the bound socket will be closed, and the resources of the monitor |
7d8787b3 KS |
478 | * will be released. |
479 | * | |
725d7e6c | 480 | * Returns: #NULL |
7d8787b3 | 481 | **/ |
20bbd54f | 482 | _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor) |
ba6929f6 | 483 | { |
912541b0 | 484 | if (udev_monitor == NULL) |
20bbd54f | 485 | return NULL; |
912541b0 KS |
486 | udev_monitor->refcount--; |
487 | if (udev_monitor->refcount > 0) | |
725d7e6c | 488 | return NULL; |
912541b0 KS |
489 | if (udev_monitor->sock >= 0) |
490 | close(udev_monitor->sock); | |
491 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); | |
492 | udev_list_cleanup(&udev_monitor->filter_tag_list); | |
912541b0 | 493 | free(udev_monitor); |
20bbd54f | 494 | return NULL; |
ba6929f6 KS |
495 | } |
496 | ||
7d8787b3 KS |
497 | /** |
498 | * udev_monitor_get_udev: | |
499 | * @udev_monitor: udev monitor | |
500 | * | |
b98fd840 | 501 | * Retrieve the udev library context the monitor was created with. |
7d8787b3 KS |
502 | * |
503 | * Returns: the udev library context | |
504 | **/ | |
54cf0b7f | 505 | _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor) |
ba6929f6 | 506 | { |
912541b0 KS |
507 | if (udev_monitor == NULL) |
508 | return NULL; | |
509 | return udev_monitor->udev; | |
ba6929f6 KS |
510 | } |
511 | ||
7d8787b3 KS |
512 | /** |
513 | * udev_monitor_get_fd: | |
514 | * @udev_monitor: udev monitor | |
515 | * | |
516 | * Retrieve the socket file descriptor associated with the monitor. | |
517 | * | |
518 | * Returns: the socket file descriptor | |
519 | **/ | |
54cf0b7f | 520 | _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
ba6929f6 | 521 | { |
912541b0 | 522 | if (udev_monitor == NULL) |
994e0234 | 523 | return -EINVAL; |
912541b0 | 524 | return udev_monitor->sock; |
ba6929f6 KS |
525 | } |
526 | ||
e14bdd88 KS |
527 | static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device) |
528 | { | |
912541b0 KS |
529 | struct udev_list_entry *list_entry; |
530 | ||
531 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL) | |
532 | goto tag; | |
533 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
534 | const char *subsys = udev_list_entry_get_name(list_entry); | |
535 | const char *dsubsys = udev_device_get_subsystem(udev_device); | |
536 | const char *devtype; | |
537 | const char *ddevtype; | |
538 | ||
090be865 | 539 | if (!streq(dsubsys, subsys)) |
912541b0 KS |
540 | continue; |
541 | ||
542 | devtype = udev_list_entry_get_value(list_entry); | |
543 | if (devtype == NULL) | |
544 | goto tag; | |
545 | ddevtype = udev_device_get_devtype(udev_device); | |
546 | if (ddevtype == NULL) | |
547 | continue; | |
090be865 | 548 | if (streq(ddevtype, devtype)) |
912541b0 KS |
549 | goto tag; |
550 | } | |
551 | return 0; | |
28460195 KS |
552 | |
553 | tag: | |
912541b0 KS |
554 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) |
555 | return 1; | |
556 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
557 | const char *tag = udev_list_entry_get_name(list_entry); | |
558 | ||
559 | if (udev_device_has_tag(udev_device, tag)) | |
560 | return 1; | |
561 | } | |
562 | return 0; | |
e14bdd88 KS |
563 | } |
564 | ||
7d8787b3 | 565 | /** |
d59f11e1 | 566 | * udev_monitor_receive_device: |
7d8787b3 KS |
567 | * @udev_monitor: udev monitor |
568 | * | |
d59f11e1 | 569 | * Receive data from the udev monitor socket, allocate a new udev |
b98fd840 | 570 | * device, fill in the received data, and return the device. |
7d8787b3 | 571 | * |
50579295 | 572 | * Only socket connections with uid=0 are accepted. |
7d8787b3 | 573 | * |
b30b4260 KS |
574 | * The monitor socket is by default set to NONBLOCK. A variant of poll() on |
575 | * the file descriptor returned by udev_monitor_get_fd() should to be used to | |
576 | * wake up when new devices arrive, or alternatively the file descriptor | |
577 | * switched into blocking mode. | |
578 | * | |
7d8787b3 | 579 | * The initial refcount is 1, and needs to be decremented to |
be7de409 | 580 | * release the resources of the udev device. |
7d8787b3 KS |
581 | * |
582 | * Returns: a new udev device, or #NULL, in case of an error | |
583 | **/ | |
54cf0b7f | 584 | _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor) |
ba6929f6 | 585 | { |
912541b0 KS |
586 | struct udev_device *udev_device; |
587 | struct msghdr smsg; | |
588 | struct iovec iov; | |
589 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
590 | struct cmsghdr *cmsg; | |
b49d9b50 | 591 | union sockaddr_union snl; |
912541b0 KS |
592 | struct ucred *cred; |
593 | char buf[8192]; | |
594 | ssize_t buflen; | |
595 | ssize_t bufpos; | |
ba6929f6 | 596 | |
e14bdd88 | 597 | retry: |
912541b0 KS |
598 | if (udev_monitor == NULL) |
599 | return NULL; | |
912541b0 KS |
600 | iov.iov_base = &buf; |
601 | iov.iov_len = sizeof(buf); | |
29804cc1 | 602 | memzero(&smsg, sizeof(struct msghdr)); |
912541b0 KS |
603 | smsg.msg_iov = &iov; |
604 | smsg.msg_iovlen = 1; | |
605 | smsg.msg_control = cred_msg; | |
606 | smsg.msg_controllen = sizeof(cred_msg); | |
f6613dd9 KS |
607 | smsg.msg_name = &snl; |
608 | smsg.msg_namelen = sizeof(snl); | |
912541b0 KS |
609 | |
610 | buflen = recvmsg(udev_monitor->sock, &smsg, 0); | |
611 | if (buflen < 0) { | |
612 | if (errno != EINTR) | |
c8f8394a | 613 | udev_dbg(udev_monitor->udev, "unable to receive message\n"); |
912541b0 KS |
614 | return NULL; |
615 | } | |
616 | ||
617 | if (buflen < 32 || (size_t)buflen >= sizeof(buf)) { | |
c8f8394a | 618 | udev_dbg(udev_monitor->udev, "invalid message length\n"); |
912541b0 KS |
619 | return NULL; |
620 | } | |
621 | ||
f6613dd9 KS |
622 | if (snl.nl.nl_groups == 0) { |
623 | /* unicast message, check if we trust the sender */ | |
624 | if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 || | |
625 | snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) { | |
626 | udev_dbg(udev_monitor->udev, "unicast netlink message ignored\n"); | |
627 | return NULL; | |
628 | } | |
629 | } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) { | |
630 | if (snl.nl.nl_pid > 0) { | |
631 | udev_dbg(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n", | |
632 | snl.nl.nl_pid); | |
633 | return NULL; | |
912541b0 KS |
634 | } |
635 | } | |
636 | ||
637 | cmsg = CMSG_FIRSTHDR(&smsg); | |
638 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
c8f8394a | 639 | udev_dbg(udev_monitor->udev, "no sender credentials received, message ignored\n"); |
912541b0 KS |
640 | return NULL; |
641 | } | |
642 | ||
643 | cred = (struct ucred *)CMSG_DATA(cmsg); | |
644 | if (cred->uid != 0) { | |
c8f8394a | 645 | udev_dbg(udev_monitor->udev, "sender uid=%d, message ignored\n", cred->uid); |
912541b0 KS |
646 | return NULL; |
647 | } | |
648 | ||
f6613dd9 KS |
649 | udev_device = udev_device_new(udev_monitor->udev); |
650 | if (udev_device == NULL) | |
651 | return NULL; | |
652 | ||
912541b0 | 653 | if (memcmp(buf, "libudev", 8) == 0) { |
f6613dd9 KS |
654 | struct udev_monitor_netlink_header *nlh; |
655 | ||
912541b0 KS |
656 | /* udev message needs proper version magic */ |
657 | nlh = (struct udev_monitor_netlink_header *) buf; | |
658 | if (nlh->magic != htonl(UDEV_MONITOR_MAGIC)) { | |
c8f8394a | 659 | udev_err(udev_monitor->udev, "unrecognized message signature (%x != %x)\n", |
f6613dd9 KS |
660 | nlh->magic, htonl(UDEV_MONITOR_MAGIC)); |
661 | udev_device_unref(udev_device); | |
912541b0 KS |
662 | return NULL; |
663 | } | |
f6613dd9 KS |
664 | if (nlh->properties_off+32 > (size_t)buflen) { |
665 | udev_device_unref(udev_device); | |
912541b0 | 666 | return NULL; |
f6613dd9 KS |
667 | } |
668 | ||
912541b0 | 669 | bufpos = nlh->properties_off; |
f6613dd9 KS |
670 | |
671 | /* devices received from udev are always initialized */ | |
672 | udev_device_set_is_initialized(udev_device); | |
912541b0 KS |
673 | } else { |
674 | /* kernel message with header */ | |
675 | bufpos = strlen(buf) + 1; | |
676 | if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { | |
c8f8394a | 677 | udev_dbg(udev_monitor->udev, "invalid message length\n"); |
f6613dd9 | 678 | udev_device_unref(udev_device); |
912541b0 KS |
679 | return NULL; |
680 | } | |
681 | ||
682 | /* check message header */ | |
683 | if (strstr(buf, "@/") == NULL) { | |
c8f8394a | 684 | udev_dbg(udev_monitor->udev, "unrecognized message header\n"); |
f6613dd9 | 685 | udev_device_unref(udev_device); |
912541b0 KS |
686 | return NULL; |
687 | } | |
688 | } | |
689 | ||
912541b0 KS |
690 | udev_device_set_info_loaded(udev_device); |
691 | ||
692 | while (bufpos < buflen) { | |
693 | char *key; | |
694 | size_t keylen; | |
695 | ||
696 | key = &buf[bufpos]; | |
697 | keylen = strlen(key); | |
698 | if (keylen == 0) | |
699 | break; | |
700 | bufpos += keylen + 1; | |
701 | udev_device_add_property_from_string_parse(udev_device, key); | |
702 | } | |
703 | ||
704 | if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) { | |
c8f8394a | 705 | udev_dbg(udev_monitor->udev, "missing values, invalid device\n"); |
912541b0 KS |
706 | udev_device_unref(udev_device); |
707 | return NULL; | |
708 | } | |
709 | ||
710 | /* skip device, if it does not pass the current filter */ | |
711 | if (!passes_filter(udev_monitor, udev_device)) { | |
712 | struct pollfd pfd[1]; | |
713 | int rc; | |
714 | ||
715 | udev_device_unref(udev_device); | |
716 | ||
717 | /* if something is queued, get next device */ | |
718 | pfd[0].fd = udev_monitor->sock; | |
719 | pfd[0].events = POLLIN; | |
720 | rc = poll(pfd, 1, 0); | |
721 | if (rc > 0) | |
722 | goto retry; | |
723 | return NULL; | |
724 | } | |
725 | ||
726 | return udev_device; | |
ba6929f6 | 727 | } |
9925ab04 | 728 | |
1e03b754 | 729 | int udev_monitor_send_device(struct udev_monitor *udev_monitor, |
912541b0 | 730 | struct udev_monitor *destination, struct udev_device *udev_device) |
9925ab04 | 731 | { |
912541b0 KS |
732 | const char *buf; |
733 | ssize_t blen; | |
734 | ssize_t count; | |
2d13da88 KS |
735 | struct msghdr smsg; |
736 | struct iovec iov[2]; | |
737 | const char *val; | |
738 | struct udev_monitor_netlink_header nlh; | |
739 | struct udev_list_entry *list_entry; | |
740 | uint64_t tag_bloom_bits; | |
741 | ||
912541b0 KS |
742 | blen = udev_device_get_properties_monitor_buf(udev_device, &buf); |
743 | if (blen < 32) | |
744 | return -EINVAL; | |
745 | ||
2d13da88 | 746 | /* add versioned header */ |
29804cc1 | 747 | memzero(&nlh, sizeof(struct udev_monitor_netlink_header)); |
2d13da88 KS |
748 | memcpy(nlh.prefix, "libudev", 8); |
749 | nlh.magic = htonl(UDEV_MONITOR_MAGIC); | |
750 | nlh.header_size = sizeof(struct udev_monitor_netlink_header); | |
751 | val = udev_device_get_subsystem(udev_device); | |
752 | nlh.filter_subsystem_hash = htonl(util_string_hash32(val)); | |
753 | val = udev_device_get_devtype(udev_device); | |
754 | if (val != NULL) | |
755 | nlh.filter_devtype_hash = htonl(util_string_hash32(val)); | |
756 | iov[0].iov_base = &nlh; | |
757 | iov[0].iov_len = sizeof(struct udev_monitor_netlink_header); | |
758 | ||
759 | /* add tag bloom filter */ | |
760 | tag_bloom_bits = 0; | |
761 | udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device)) | |
762 | tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
763 | if (tag_bloom_bits > 0) { | |
764 | nlh.filter_tag_bloom_hi = htonl(tag_bloom_bits >> 32); | |
765 | nlh.filter_tag_bloom_lo = htonl(tag_bloom_bits & 0xffffffff); | |
912541b0 KS |
766 | } |
767 | ||
2d13da88 KS |
768 | /* add properties list */ |
769 | nlh.properties_off = iov[0].iov_len; | |
770 | nlh.properties_len = blen; | |
771 | iov[1].iov_base = (char *)buf; | |
772 | iov[1].iov_len = blen; | |
912541b0 | 773 | |
29804cc1 | 774 | memzero(&smsg, sizeof(struct msghdr)); |
2d13da88 KS |
775 | smsg.msg_iov = iov; |
776 | smsg.msg_iovlen = 2; | |
777 | /* | |
778 | * Use custom address for target, or the default one. | |
779 | * | |
780 | * If we send to a multicast group, we will get | |
781 | * ECONNREFUSED, which is expected. | |
782 | */ | |
783 | if (destination != NULL) | |
784 | smsg.msg_name = &destination->snl; | |
785 | else | |
786 | smsg.msg_name = &udev_monitor->snl_destination; | |
787 | smsg.msg_namelen = sizeof(struct sockaddr_nl); | |
788 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
c8f8394a | 789 | udev_dbg(udev_monitor->udev, "passed %zi bytes to netlink monitor %p\n", count, udev_monitor); |
2d13da88 | 790 | return count; |
9925ab04 | 791 | } |
e14bdd88 | 792 | |
ce1d6d7f KS |
793 | /** |
794 | * udev_monitor_filter_add_match_subsystem_devtype: | |
795 | * @udev_monitor: the monitor | |
796 | * @subsystem: the subsystem value to match the incoming devices against | |
214a6c79 | 797 | * @devtype: the devtype value to match the incoming devices against |
ce1d6d7f | 798 | * |
50579295 | 799 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
800 | * will usually not be woken up for devices which do not match. |
801 | * | |
ce1d6d7f KS |
802 | * The filter must be installed before the monitor is switched to listening mode. |
803 | * | |
804 | * Returns: 0 on success, otherwise a negative error value. | |
805 | */ | |
54cf0b7f | 806 | _public_ int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype) |
e14bdd88 | 807 | { |
912541b0 KS |
808 | if (udev_monitor == NULL) |
809 | return -EINVAL; | |
810 | if (subsystem == NULL) | |
811 | return -EINVAL; | |
812 | if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL) | |
813 | return -ENOMEM; | |
814 | return 0; | |
e14bdd88 | 815 | } |
08a7a795 | 816 | |
28460195 KS |
817 | /** |
818 | * udev_monitor_filter_add_match_tag: | |
819 | * @udev_monitor: the monitor | |
820 | * @tag: the name of a tag | |
821 | * | |
50579295 | 822 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
823 | * will usually not be woken up for devices which do not match. |
824 | * | |
825 | * The filter must be installed before the monitor is switched to listening mode. | |
826 | * | |
827 | * Returns: 0 on success, otherwise a negative error value. | |
828 | */ | |
54cf0b7f | 829 | _public_ int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag) |
28460195 | 830 | { |
912541b0 KS |
831 | if (udev_monitor == NULL) |
832 | return -EINVAL; | |
833 | if (tag == NULL) | |
834 | return -EINVAL; | |
835 | if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL) | |
836 | return -ENOMEM; | |
837 | return 0; | |
28460195 KS |
838 | } |
839 | ||
ce1d6d7f KS |
840 | /** |
841 | * udev_monitor_filter_remove: | |
842 | * @udev_monitor: monitor | |
843 | * | |
844 | * Remove all filters from monitor. | |
845 | * | |
846 | * Returns: 0 on success, otherwise a negative error value. | |
847 | */ | |
54cf0b7f | 848 | _public_ int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
08a7a795 | 849 | { |
912541b0 | 850 | static struct sock_fprog filter = { 0, NULL }; |
08a7a795 | 851 | |
912541b0 KS |
852 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
853 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
08a7a795 | 854 | } |