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Commit | Line | Data |
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ba6929f6 KS |
1 | /* |
2 | * libudev - interface to udev device information | |
3 | * | |
28460195 | 4 | * Copyright (C) 2008-2010 Kay Sievers <kay.sievers@vrfy.org> |
ba6929f6 | 5 | * |
4061ab9f KS |
6 | * This library is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
ba6929f6 KS |
10 | */ |
11 | ||
ba6929f6 KS |
12 | #include <stdio.h> |
13 | #include <stdlib.h> | |
14 | #include <stddef.h> | |
15 | #include <unistd.h> | |
16 | #include <errno.h> | |
17 | #include <string.h> | |
18 | #include <dirent.h> | |
e14bdd88 | 19 | #include <sys/poll.h> |
ba6929f6 KS |
20 | #include <sys/stat.h> |
21 | #include <sys/socket.h> | |
22 | #include <sys/un.h> | |
e14bdd88 | 23 | #include <arpa/inet.h> |
1c7047ea | 24 | #include <linux/netlink.h> |
e14bdd88 | 25 | #include <linux/filter.h> |
ba6929f6 KS |
26 | |
27 | #include "libudev.h" | |
28 | #include "libudev-private.h" | |
b49d9b50 | 29 | #include "socket-util.h" |
ba6929f6 | 30 | |
ce1d6d7f KS |
31 | /** |
32 | * SECTION:libudev-monitor | |
33 | * @short_description: device event source | |
34 | * | |
35 | * Connects to a device event source. | |
36 | */ | |
37 | ||
ce1d6d7f KS |
38 | /** |
39 | * udev_monitor: | |
40 | * | |
50579295 | 41 | * Opaque object handling an event source. |
ce1d6d7f | 42 | */ |
ba6929f6 | 43 | struct udev_monitor { |
912541b0 KS |
44 | struct udev *udev; |
45 | int refcount; | |
46 | int sock; | |
b49d9b50 KS |
47 | union sockaddr_union snl; |
48 | union sockaddr_union snl_trusted_sender; | |
49 | union sockaddr_union snl_destination; | |
912541b0 KS |
50 | socklen_t addrlen; |
51 | struct udev_list filter_subsystem_list; | |
52 | struct udev_list filter_tag_list; | |
53 | bool bound; | |
ba6929f6 KS |
54 | }; |
55 | ||
f2b93744 | 56 | enum udev_monitor_netlink_group { |
912541b0 KS |
57 | UDEV_MONITOR_NONE, |
58 | UDEV_MONITOR_KERNEL, | |
59 | UDEV_MONITOR_UDEV, | |
f2b93744 KS |
60 | }; |
61 | ||
912541b0 | 62 | #define UDEV_MONITOR_MAGIC 0xfeedcafe |
e14bdd88 | 63 | struct udev_monitor_netlink_header { |
912541b0 KS |
64 | /* "libudev" prefix to distinguish libudev and kernel messages */ |
65 | char prefix[8]; | |
66 | /* | |
67 | * magic to protect against daemon <-> library message format mismatch | |
68 | * used in the kernel from socket filter rules; needs to be stored in network order | |
69 | */ | |
70 | unsigned int magic; | |
71 | /* total length of header structure known to the sender */ | |
72 | unsigned int header_size; | |
73 | /* properties string buffer */ | |
74 | unsigned int properties_off; | |
75 | unsigned int properties_len; | |
76 | /* | |
77 | * hashes of primary device properties strings, to let libudev subscribers | |
78 | * use in-kernel socket filters; values need to be stored in network order | |
79 | */ | |
80 | unsigned int filter_subsystem_hash; | |
81 | unsigned int filter_devtype_hash; | |
82 | unsigned int filter_tag_bloom_hi; | |
83 | unsigned int filter_tag_bloom_lo; | |
e14bdd88 KS |
84 | }; |
85 | ||
86 | static struct udev_monitor *udev_monitor_new(struct udev *udev) | |
87 | { | |
912541b0 KS |
88 | struct udev_monitor *udev_monitor; |
89 | ||
90 | udev_monitor = calloc(1, sizeof(struct udev_monitor)); | |
91 | if (udev_monitor == NULL) | |
92 | return NULL; | |
93 | udev_monitor->refcount = 1; | |
94 | udev_monitor->udev = udev; | |
95 | udev_list_init(udev, &udev_monitor->filter_subsystem_list, false); | |
96 | udev_list_init(udev, &udev_monitor->filter_tag_list, true); | |
97 | return udev_monitor; | |
e14bdd88 KS |
98 | } |
99 | ||
7459bcdc | 100 | struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) |
1c7047ea | 101 | { |
912541b0 KS |
102 | struct udev_monitor *udev_monitor; |
103 | unsigned int group; | |
104 | ||
105 | if (udev == NULL) | |
106 | return NULL; | |
107 | ||
108 | if (name == NULL) | |
109 | group = UDEV_MONITOR_NONE; | |
110 | else if (strcmp(name, "udev") == 0) | |
111 | group = UDEV_MONITOR_UDEV; | |
112 | else if (strcmp(name, "kernel") == 0) | |
113 | group = UDEV_MONITOR_KERNEL; | |
114 | else | |
115 | return NULL; | |
116 | ||
117 | udev_monitor = udev_monitor_new(udev); | |
118 | if (udev_monitor == NULL) | |
119 | return NULL; | |
120 | ||
121 | if (fd < 0) { | |
122 | udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); | |
123 | if (udev_monitor->sock == -1) { | |
c8f8394a | 124 | udev_err(udev, "error getting socket: %m\n"); |
912541b0 KS |
125 | free(udev_monitor); |
126 | return NULL; | |
127 | } | |
128 | } else { | |
129 | udev_monitor->bound = true; | |
130 | udev_monitor->sock = fd; | |
131 | } | |
132 | ||
b49d9b50 KS |
133 | udev_monitor->snl.nl.nl_family = AF_NETLINK; |
134 | udev_monitor->snl.nl.nl_groups = group; | |
912541b0 KS |
135 | |
136 | /* default destination for sending */ | |
b49d9b50 KS |
137 | udev_monitor->snl_destination.nl.nl_family = AF_NETLINK; |
138 | udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV; | |
912541b0 | 139 | |
912541b0 | 140 | return udev_monitor; |
1c7047ea KS |
141 | } |
142 | ||
7459bcdc KS |
143 | /** |
144 | * udev_monitor_new_from_netlink: | |
145 | * @udev: udev library context | |
146 | * @name: name of event source | |
147 | * | |
148 | * Create new udev monitor and connect to a specified event | |
149 | * source. Valid sources identifiers are "udev" and "kernel". | |
150 | * | |
151 | * Applications should usually not connect directly to the | |
152 | * "kernel" events, because the devices might not be useable | |
153 | * at that time, before udev has configured them, and created | |
50579295 KS |
154 | * device nodes. Accessing devices at the same time as udev, |
155 | * might result in unpredictable behavior. The "udev" events | |
156 | * are sent out after udev has finished its event processing, | |
157 | * all rules have been processed, and needed device nodes are | |
158 | * created. | |
7459bcdc KS |
159 | * |
160 | * The initial refcount is 1, and needs to be decremented to | |
161 | * release the resources of the udev monitor. | |
162 | * | |
163 | * Returns: a new udev monitor, or #NULL, in case of an error | |
164 | **/ | |
54cf0b7f | 165 | _public_ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) |
7459bcdc | 166 | { |
912541b0 | 167 | return udev_monitor_new_from_netlink_fd(udev, name, -1); |
7459bcdc KS |
168 | } |
169 | ||
e14bdd88 | 170 | static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i, |
912541b0 | 171 | unsigned short code, unsigned int data) |
e14bdd88 | 172 | { |
912541b0 | 173 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 174 | |
912541b0 KS |
175 | ins->code = code; |
176 | ins->k = data; | |
177 | (*i)++; | |
e14bdd88 KS |
178 | } |
179 | ||
180 | static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i, | |
912541b0 KS |
181 | unsigned short code, unsigned int data, |
182 | unsigned short jt, unsigned short jf) | |
e14bdd88 | 183 | { |
912541b0 | 184 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 185 | |
912541b0 KS |
186 | ins->code = code; |
187 | ins->jt = jt; | |
188 | ins->jf = jf; | |
189 | ins->k = data; | |
190 | (*i)++; | |
e14bdd88 KS |
191 | } |
192 | ||
ce1d6d7f KS |
193 | /** |
194 | * udev_monitor_filter_update: | |
195 | * @udev_monitor: monitor | |
196 | * | |
50579295 KS |
197 | * Update the installed socket filter. This is only needed, |
198 | * if the filter was removed or changed. | |
ce1d6d7f KS |
199 | * |
200 | * Returns: 0 on success, otherwise a negative error value. | |
201 | */ | |
54cf0b7f | 202 | _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor) |
e14bdd88 | 203 | { |
912541b0 KS |
204 | struct sock_filter ins[512]; |
205 | struct sock_fprog filter; | |
206 | unsigned int i; | |
207 | struct udev_list_entry *list_entry; | |
208 | int err; | |
209 | ||
210 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL && | |
211 | udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) | |
212 | return 0; | |
213 | ||
214 | memset(ins, 0x00, sizeof(ins)); | |
215 | i = 0; | |
216 | ||
217 | /* load magic in A */ | |
218 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic)); | |
219 | /* jump if magic matches */ | |
220 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); | |
221 | /* wrong magic, pass packet */ | |
222 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
223 | ||
224 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) { | |
225 | int tag_matches; | |
226 | ||
227 | /* count tag matches, to calculate end of tag match block */ | |
228 | tag_matches = 0; | |
229 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) | |
230 | tag_matches++; | |
231 | ||
232 | /* add all tags matches */ | |
233 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
234 | uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
235 | uint32_t tag_bloom_hi = tag_bloom_bits >> 32; | |
236 | uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; | |
237 | ||
238 | /* load device bloom bits in A */ | |
239 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi)); | |
240 | /* clear bits (tag bits & bloom bits) */ | |
241 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); | |
242 | /* jump to next tag if it does not match */ | |
243 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); | |
244 | ||
245 | /* load device bloom bits in A */ | |
246 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo)); | |
247 | /* clear bits (tag bits & bloom bits) */ | |
248 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); | |
249 | /* jump behind end of tag match block if tag matches */ | |
250 | tag_matches--; | |
251 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); | |
252 | } | |
253 | ||
254 | /* nothing matched, drop packet */ | |
255 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
256 | } | |
257 | ||
258 | /* add all subsystem matches */ | |
259 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) { | |
260 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
261 | unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry)); | |
262 | ||
263 | /* load device subsystem value in A */ | |
264 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash)); | |
265 | if (udev_list_entry_get_value(list_entry) == NULL) { | |
266 | /* jump if subsystem does not match */ | |
267 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
268 | } else { | |
269 | /* jump if subsystem does not match */ | |
270 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); | |
271 | ||
272 | /* load device devtype value in A */ | |
273 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash)); | |
274 | /* jump if value does not match */ | |
275 | hash = util_string_hash32(udev_list_entry_get_value(list_entry)); | |
276 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
277 | } | |
278 | ||
279 | /* matched, pass packet */ | |
280 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
281 | ||
8fef0ff2 | 282 | if (i+1 >= ELEMENTSOF(ins)) |
912541b0 KS |
283 | return -1; |
284 | } | |
285 | ||
286 | /* nothing matched, drop packet */ | |
287 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
288 | } | |
289 | ||
290 | /* matched, pass packet */ | |
291 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
292 | ||
293 | /* install filter */ | |
294 | memset(&filter, 0x00, sizeof(filter)); | |
295 | filter.len = i; | |
296 | filter.filter = ins; | |
297 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
298 | return err; | |
e14bdd88 KS |
299 | } |
300 | ||
1e03b754 KS |
301 | int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
302 | { | |
b49d9b50 | 303 | udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid; |
912541b0 | 304 | return 0; |
1e03b754 | 305 | } |
ce1d6d7f KS |
306 | /** |
307 | * udev_monitor_enable_receiving: | |
308 | * @udev_monitor: the monitor which should receive events | |
309 | * | |
310 | * Binds the @udev_monitor socket to the event source. | |
311 | * | |
312 | * Returns: 0 on success, otherwise a negative error value. | |
313 | */ | |
54cf0b7f | 314 | _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
d59f11e1 | 315 | { |
912541b0 KS |
316 | int err = 0; |
317 | const int on = 1; | |
318 | ||
b49d9b50 | 319 | if (udev_monitor->snl.nl.nl_family == 0) |
912541b0 | 320 | return -EINVAL; |
2d13da88 KS |
321 | |
322 | udev_monitor_filter_update(udev_monitor); | |
323 | ||
324 | if (!udev_monitor->bound) { | |
325 | err = bind(udev_monitor->sock, | |
b49d9b50 | 326 | &udev_monitor->snl.sa, sizeof(struct sockaddr_nl)); |
2d13da88 KS |
327 | if (err == 0) |
328 | udev_monitor->bound = true; | |
912541b0 KS |
329 | } |
330 | ||
2d13da88 | 331 | if (err >= 0) { |
b49d9b50 | 332 | union sockaddr_union snl; |
2d13da88 KS |
333 | socklen_t addrlen; |
334 | ||
335 | /* | |
336 | * get the address the kernel has assigned us | |
337 | * it is usually, but not necessarily the pid | |
338 | */ | |
339 | addrlen = sizeof(struct sockaddr_nl); | |
b49d9b50 | 340 | err = getsockname(udev_monitor->sock, &snl.sa, &addrlen); |
2d13da88 | 341 | if (err == 0) |
b49d9b50 | 342 | udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid; |
2d13da88 | 343 | } else { |
c8f8394a | 344 | udev_err(udev_monitor->udev, "bind failed: %m\n"); |
912541b0 KS |
345 | return err; |
346 | } | |
347 | ||
348 | /* enable receiving of sender credentials */ | |
349 | setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); | |
350 | return 0; | |
ba6929f6 KS |
351 | } |
352 | ||
f712894d KS |
353 | /** |
354 | * udev_monitor_set_receive_buffer_size: | |
355 | * @udev_monitor: the monitor which should receive events | |
356 | * @size: the size in bytes | |
357 | * | |
358 | * Set the size of the kernel socket buffer. This call needs the | |
359 | * appropriate privileges to succeed. | |
360 | * | |
361 | * Returns: 0 on success, otherwise -1 on error. | |
362 | */ | |
54cf0b7f | 363 | _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
cb25a958 | 364 | { |
912541b0 KS |
365 | if (udev_monitor == NULL) |
366 | return -1; | |
367 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)); | |
cb25a958 KS |
368 | } |
369 | ||
1e03b754 KS |
370 | int udev_monitor_disconnect(struct udev_monitor *udev_monitor) |
371 | { | |
912541b0 | 372 | int err; |
1e03b754 | 373 | |
912541b0 KS |
374 | err = close(udev_monitor->sock); |
375 | udev_monitor->sock = -1; | |
376 | return err; | |
1e03b754 KS |
377 | } |
378 | ||
7d8787b3 KS |
379 | /** |
380 | * udev_monitor_ref: | |
381 | * @udev_monitor: udev monitor | |
382 | * | |
383 | * Take a reference of a udev monitor. | |
384 | * | |
385 | * Returns: the passed udev monitor | |
386 | **/ | |
54cf0b7f | 387 | _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor) |
ba6929f6 | 388 | { |
912541b0 KS |
389 | if (udev_monitor == NULL) |
390 | return NULL; | |
391 | udev_monitor->refcount++; | |
392 | return udev_monitor; | |
ba6929f6 KS |
393 | } |
394 | ||
7d8787b3 KS |
395 | /** |
396 | * udev_monitor_unref: | |
397 | * @udev_monitor: udev monitor | |
398 | * | |
ff109b8d | 399 | * Drop a reference of a udev monitor. If the refcount reaches zero, |
be7de409 | 400 | * the bound socket will be closed, and the resources of the monitor |
7d8787b3 KS |
401 | * will be released. |
402 | * | |
c1959569 | 403 | * Returns: the passed udev monitor if it has still an active reference, or #NULL otherwise. |
7d8787b3 | 404 | **/ |
20bbd54f | 405 | _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor) |
ba6929f6 | 406 | { |
912541b0 | 407 | if (udev_monitor == NULL) |
20bbd54f | 408 | return NULL; |
912541b0 KS |
409 | udev_monitor->refcount--; |
410 | if (udev_monitor->refcount > 0) | |
20bbd54f | 411 | return udev_monitor; |
912541b0 KS |
412 | if (udev_monitor->sock >= 0) |
413 | close(udev_monitor->sock); | |
414 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); | |
415 | udev_list_cleanup(&udev_monitor->filter_tag_list); | |
912541b0 | 416 | free(udev_monitor); |
20bbd54f | 417 | return NULL; |
ba6929f6 KS |
418 | } |
419 | ||
7d8787b3 KS |
420 | /** |
421 | * udev_monitor_get_udev: | |
422 | * @udev_monitor: udev monitor | |
423 | * | |
b98fd840 | 424 | * Retrieve the udev library context the monitor was created with. |
7d8787b3 KS |
425 | * |
426 | * Returns: the udev library context | |
427 | **/ | |
54cf0b7f | 428 | _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor) |
ba6929f6 | 429 | { |
912541b0 KS |
430 | if (udev_monitor == NULL) |
431 | return NULL; | |
432 | return udev_monitor->udev; | |
ba6929f6 KS |
433 | } |
434 | ||
7d8787b3 KS |
435 | /** |
436 | * udev_monitor_get_fd: | |
437 | * @udev_monitor: udev monitor | |
438 | * | |
439 | * Retrieve the socket file descriptor associated with the monitor. | |
440 | * | |
441 | * Returns: the socket file descriptor | |
442 | **/ | |
54cf0b7f | 443 | _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
ba6929f6 | 444 | { |
912541b0 KS |
445 | if (udev_monitor == NULL) |
446 | return -1; | |
447 | return udev_monitor->sock; | |
ba6929f6 KS |
448 | } |
449 | ||
e14bdd88 KS |
450 | static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device) |
451 | { | |
912541b0 KS |
452 | struct udev_list_entry *list_entry; |
453 | ||
454 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL) | |
455 | goto tag; | |
456 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
457 | const char *subsys = udev_list_entry_get_name(list_entry); | |
458 | const char *dsubsys = udev_device_get_subsystem(udev_device); | |
459 | const char *devtype; | |
460 | const char *ddevtype; | |
461 | ||
462 | if (strcmp(dsubsys, subsys) != 0) | |
463 | continue; | |
464 | ||
465 | devtype = udev_list_entry_get_value(list_entry); | |
466 | if (devtype == NULL) | |
467 | goto tag; | |
468 | ddevtype = udev_device_get_devtype(udev_device); | |
469 | if (ddevtype == NULL) | |
470 | continue; | |
471 | if (strcmp(ddevtype, devtype) == 0) | |
472 | goto tag; | |
473 | } | |
474 | return 0; | |
28460195 KS |
475 | |
476 | tag: | |
912541b0 KS |
477 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) |
478 | return 1; | |
479 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
480 | const char *tag = udev_list_entry_get_name(list_entry); | |
481 | ||
482 | if (udev_device_has_tag(udev_device, tag)) | |
483 | return 1; | |
484 | } | |
485 | return 0; | |
e14bdd88 KS |
486 | } |
487 | ||
7d8787b3 | 488 | /** |
d59f11e1 | 489 | * udev_monitor_receive_device: |
7d8787b3 KS |
490 | * @udev_monitor: udev monitor |
491 | * | |
d59f11e1 | 492 | * Receive data from the udev monitor socket, allocate a new udev |
b98fd840 | 493 | * device, fill in the received data, and return the device. |
7d8787b3 | 494 | * |
50579295 | 495 | * Only socket connections with uid=0 are accepted. |
7d8787b3 KS |
496 | * |
497 | * The initial refcount is 1, and needs to be decremented to | |
be7de409 | 498 | * release the resources of the udev device. |
7d8787b3 KS |
499 | * |
500 | * Returns: a new udev device, or #NULL, in case of an error | |
501 | **/ | |
54cf0b7f | 502 | _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor) |
ba6929f6 | 503 | { |
912541b0 KS |
504 | struct udev_device *udev_device; |
505 | struct msghdr smsg; | |
506 | struct iovec iov; | |
507 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
508 | struct cmsghdr *cmsg; | |
b49d9b50 | 509 | union sockaddr_union snl; |
912541b0 KS |
510 | struct ucred *cred; |
511 | char buf[8192]; | |
512 | ssize_t buflen; | |
513 | ssize_t bufpos; | |
514 | struct udev_monitor_netlink_header *nlh; | |
ba6929f6 | 515 | |
e14bdd88 | 516 | retry: |
912541b0 KS |
517 | if (udev_monitor == NULL) |
518 | return NULL; | |
912541b0 KS |
519 | iov.iov_base = &buf; |
520 | iov.iov_len = sizeof(buf); | |
521 | memset (&smsg, 0x00, sizeof(struct msghdr)); | |
522 | smsg.msg_iov = &iov; | |
523 | smsg.msg_iovlen = 1; | |
524 | smsg.msg_control = cred_msg; | |
525 | smsg.msg_controllen = sizeof(cred_msg); | |
526 | ||
b49d9b50 | 527 | if (udev_monitor->snl.nl.nl_family != 0) { |
912541b0 KS |
528 | smsg.msg_name = &snl; |
529 | smsg.msg_namelen = sizeof(snl); | |
530 | } | |
531 | ||
532 | buflen = recvmsg(udev_monitor->sock, &smsg, 0); | |
533 | if (buflen < 0) { | |
534 | if (errno != EINTR) | |
c8f8394a | 535 | udev_dbg(udev_monitor->udev, "unable to receive message\n"); |
912541b0 KS |
536 | return NULL; |
537 | } | |
538 | ||
539 | if (buflen < 32 || (size_t)buflen >= sizeof(buf)) { | |
c8f8394a | 540 | udev_dbg(udev_monitor->udev, "invalid message length\n"); |
912541b0 KS |
541 | return NULL; |
542 | } | |
543 | ||
b49d9b50 KS |
544 | if (udev_monitor->snl.nl.nl_family != 0) { |
545 | if (snl.nl.nl_groups == 0) { | |
912541b0 | 546 | /* unicast message, check if we trust the sender */ |
b49d9b50 KS |
547 | if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 || |
548 | snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) { | |
c8f8394a | 549 | udev_dbg(udev_monitor->udev, "unicast netlink message ignored\n"); |
912541b0 KS |
550 | return NULL; |
551 | } | |
b49d9b50 KS |
552 | } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) { |
553 | if (snl.nl.nl_pid > 0) { | |
c8f8394a | 554 | udev_dbg(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n", |
b49d9b50 | 555 | snl.nl.nl_pid); |
912541b0 KS |
556 | return NULL; |
557 | } | |
558 | } | |
559 | } | |
560 | ||
561 | cmsg = CMSG_FIRSTHDR(&smsg); | |
562 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
c8f8394a | 563 | udev_dbg(udev_monitor->udev, "no sender credentials received, message ignored\n"); |
912541b0 KS |
564 | return NULL; |
565 | } | |
566 | ||
567 | cred = (struct ucred *)CMSG_DATA(cmsg); | |
568 | if (cred->uid != 0) { | |
c8f8394a | 569 | udev_dbg(udev_monitor->udev, "sender uid=%d, message ignored\n", cred->uid); |
912541b0 KS |
570 | return NULL; |
571 | } | |
572 | ||
573 | if (memcmp(buf, "libudev", 8) == 0) { | |
574 | /* udev message needs proper version magic */ | |
575 | nlh = (struct udev_monitor_netlink_header *) buf; | |
576 | if (nlh->magic != htonl(UDEV_MONITOR_MAGIC)) { | |
c8f8394a | 577 | udev_err(udev_monitor->udev, "unrecognized message signature (%x != %x)\n", |
912541b0 KS |
578 | nlh->magic, htonl(UDEV_MONITOR_MAGIC)); |
579 | return NULL; | |
580 | } | |
ee56538f | 581 | if (nlh->properties_off+32 > (size_t)buflen) |
912541b0 KS |
582 | return NULL; |
583 | bufpos = nlh->properties_off; | |
584 | } else { | |
585 | /* kernel message with header */ | |
586 | bufpos = strlen(buf) + 1; | |
587 | if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { | |
c8f8394a | 588 | udev_dbg(udev_monitor->udev, "invalid message length\n"); |
912541b0 KS |
589 | return NULL; |
590 | } | |
591 | ||
592 | /* check message header */ | |
593 | if (strstr(buf, "@/") == NULL) { | |
c8f8394a | 594 | udev_dbg(udev_monitor->udev, "unrecognized message header\n"); |
912541b0 KS |
595 | return NULL; |
596 | } | |
597 | } | |
598 | ||
599 | udev_device = udev_device_new(udev_monitor->udev); | |
600 | if (udev_device == NULL) | |
601 | return NULL; | |
602 | udev_device_set_info_loaded(udev_device); | |
603 | ||
604 | while (bufpos < buflen) { | |
605 | char *key; | |
606 | size_t keylen; | |
607 | ||
608 | key = &buf[bufpos]; | |
609 | keylen = strlen(key); | |
610 | if (keylen == 0) | |
611 | break; | |
612 | bufpos += keylen + 1; | |
613 | udev_device_add_property_from_string_parse(udev_device, key); | |
614 | } | |
615 | ||
616 | if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) { | |
c8f8394a | 617 | udev_dbg(udev_monitor->udev, "missing values, invalid device\n"); |
912541b0 KS |
618 | udev_device_unref(udev_device); |
619 | return NULL; | |
620 | } | |
621 | ||
622 | /* skip device, if it does not pass the current filter */ | |
623 | if (!passes_filter(udev_monitor, udev_device)) { | |
624 | struct pollfd pfd[1]; | |
625 | int rc; | |
626 | ||
627 | udev_device_unref(udev_device); | |
628 | ||
629 | /* if something is queued, get next device */ | |
630 | pfd[0].fd = udev_monitor->sock; | |
631 | pfd[0].events = POLLIN; | |
632 | rc = poll(pfd, 1, 0); | |
633 | if (rc > 0) | |
634 | goto retry; | |
635 | return NULL; | |
636 | } | |
637 | ||
638 | return udev_device; | |
ba6929f6 | 639 | } |
9925ab04 | 640 | |
1e03b754 | 641 | int udev_monitor_send_device(struct udev_monitor *udev_monitor, |
912541b0 | 642 | struct udev_monitor *destination, struct udev_device *udev_device) |
9925ab04 | 643 | { |
912541b0 KS |
644 | const char *buf; |
645 | ssize_t blen; | |
646 | ssize_t count; | |
2d13da88 KS |
647 | struct msghdr smsg; |
648 | struct iovec iov[2]; | |
649 | const char *val; | |
650 | struct udev_monitor_netlink_header nlh; | |
651 | struct udev_list_entry *list_entry; | |
652 | uint64_t tag_bloom_bits; | |
653 | ||
b49d9b50 | 654 | if (udev_monitor->snl.nl.nl_family == 0) |
2d13da88 | 655 | return -EINVAL; |
912541b0 KS |
656 | |
657 | blen = udev_device_get_properties_monitor_buf(udev_device, &buf); | |
658 | if (blen < 32) | |
659 | return -EINVAL; | |
660 | ||
2d13da88 KS |
661 | /* add versioned header */ |
662 | memset(&nlh, 0x00, sizeof(struct udev_monitor_netlink_header)); | |
663 | memcpy(nlh.prefix, "libudev", 8); | |
664 | nlh.magic = htonl(UDEV_MONITOR_MAGIC); | |
665 | nlh.header_size = sizeof(struct udev_monitor_netlink_header); | |
666 | val = udev_device_get_subsystem(udev_device); | |
667 | nlh.filter_subsystem_hash = htonl(util_string_hash32(val)); | |
668 | val = udev_device_get_devtype(udev_device); | |
669 | if (val != NULL) | |
670 | nlh.filter_devtype_hash = htonl(util_string_hash32(val)); | |
671 | iov[0].iov_base = &nlh; | |
672 | iov[0].iov_len = sizeof(struct udev_monitor_netlink_header); | |
673 | ||
674 | /* add tag bloom filter */ | |
675 | tag_bloom_bits = 0; | |
676 | udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device)) | |
677 | tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
678 | if (tag_bloom_bits > 0) { | |
679 | nlh.filter_tag_bloom_hi = htonl(tag_bloom_bits >> 32); | |
680 | nlh.filter_tag_bloom_lo = htonl(tag_bloom_bits & 0xffffffff); | |
912541b0 KS |
681 | } |
682 | ||
2d13da88 KS |
683 | /* add properties list */ |
684 | nlh.properties_off = iov[0].iov_len; | |
685 | nlh.properties_len = blen; | |
686 | iov[1].iov_base = (char *)buf; | |
687 | iov[1].iov_len = blen; | |
912541b0 | 688 | |
2d13da88 KS |
689 | memset(&smsg, 0x00, sizeof(struct msghdr)); |
690 | smsg.msg_iov = iov; | |
691 | smsg.msg_iovlen = 2; | |
692 | /* | |
693 | * Use custom address for target, or the default one. | |
694 | * | |
695 | * If we send to a multicast group, we will get | |
696 | * ECONNREFUSED, which is expected. | |
697 | */ | |
698 | if (destination != NULL) | |
699 | smsg.msg_name = &destination->snl; | |
700 | else | |
701 | smsg.msg_name = &udev_monitor->snl_destination; | |
702 | smsg.msg_namelen = sizeof(struct sockaddr_nl); | |
703 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
c8f8394a | 704 | udev_dbg(udev_monitor->udev, "passed %zi bytes to netlink monitor %p\n", count, udev_monitor); |
2d13da88 | 705 | return count; |
9925ab04 | 706 | } |
e14bdd88 | 707 | |
ce1d6d7f KS |
708 | /** |
709 | * udev_monitor_filter_add_match_subsystem_devtype: | |
710 | * @udev_monitor: the monitor | |
711 | * @subsystem: the subsystem value to match the incoming devices against | |
214a6c79 | 712 | * @devtype: the devtype value to match the incoming devices against |
ce1d6d7f | 713 | * |
50579295 | 714 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
715 | * will usually not be woken up for devices which do not match. |
716 | * | |
ce1d6d7f KS |
717 | * The filter must be installed before the monitor is switched to listening mode. |
718 | * | |
719 | * Returns: 0 on success, otherwise a negative error value. | |
720 | */ | |
54cf0b7f | 721 | _public_ int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype) |
e14bdd88 | 722 | { |
912541b0 KS |
723 | if (udev_monitor == NULL) |
724 | return -EINVAL; | |
725 | if (subsystem == NULL) | |
726 | return -EINVAL; | |
727 | if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL) | |
728 | return -ENOMEM; | |
729 | return 0; | |
e14bdd88 | 730 | } |
08a7a795 | 731 | |
28460195 KS |
732 | /** |
733 | * udev_monitor_filter_add_match_tag: | |
734 | * @udev_monitor: the monitor | |
735 | * @tag: the name of a tag | |
736 | * | |
50579295 | 737 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
738 | * will usually not be woken up for devices which do not match. |
739 | * | |
740 | * The filter must be installed before the monitor is switched to listening mode. | |
741 | * | |
742 | * Returns: 0 on success, otherwise a negative error value. | |
743 | */ | |
54cf0b7f | 744 | _public_ int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag) |
28460195 | 745 | { |
912541b0 KS |
746 | if (udev_monitor == NULL) |
747 | return -EINVAL; | |
748 | if (tag == NULL) | |
749 | return -EINVAL; | |
750 | if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL) | |
751 | return -ENOMEM; | |
752 | return 0; | |
28460195 KS |
753 | } |
754 | ||
ce1d6d7f KS |
755 | /** |
756 | * udev_monitor_filter_remove: | |
757 | * @udev_monitor: monitor | |
758 | * | |
759 | * Remove all filters from monitor. | |
760 | * | |
761 | * Returns: 0 on success, otherwise a negative error value. | |
762 | */ | |
54cf0b7f | 763 | _public_ int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
08a7a795 | 764 | { |
912541b0 | 765 | static struct sock_fprog filter = { 0, NULL }; |
08a7a795 | 766 | |
912541b0 KS |
767 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
768 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
08a7a795 | 769 | } |