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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" |
ba6929f6 | 38 | |
ce1d6d7f KS |
39 | /** |
40 | * SECTION:libudev-monitor | |
41 | * @short_description: device event source | |
42 | * | |
43 | * Connects to a device event source. | |
44 | */ | |
45 | ||
ce1d6d7f KS |
46 | /** |
47 | * udev_monitor: | |
48 | * | |
50579295 | 49 | * Opaque object handling an event source. |
ce1d6d7f | 50 | */ |
ba6929f6 | 51 | struct udev_monitor { |
912541b0 KS |
52 | struct udev *udev; |
53 | int refcount; | |
54 | int sock; | |
b49d9b50 KS |
55 | union sockaddr_union snl; |
56 | union sockaddr_union snl_trusted_sender; | |
57 | union sockaddr_union snl_destination; | |
912541b0 KS |
58 | socklen_t addrlen; |
59 | struct udev_list filter_subsystem_list; | |
60 | struct udev_list filter_tag_list; | |
61 | bool bound; | |
ba6929f6 KS |
62 | }; |
63 | ||
f2b93744 | 64 | enum udev_monitor_netlink_group { |
912541b0 KS |
65 | UDEV_MONITOR_NONE, |
66 | UDEV_MONITOR_KERNEL, | |
67 | UDEV_MONITOR_UDEV, | |
f2b93744 KS |
68 | }; |
69 | ||
912541b0 | 70 | #define UDEV_MONITOR_MAGIC 0xfeedcafe |
e14bdd88 | 71 | struct udev_monitor_netlink_header { |
912541b0 KS |
72 | /* "libudev" prefix to distinguish libudev and kernel messages */ |
73 | char prefix[8]; | |
74 | /* | |
75 | * magic to protect against daemon <-> library message format mismatch | |
76 | * used in the kernel from socket filter rules; needs to be stored in network order | |
77 | */ | |
78 | unsigned int magic; | |
79 | /* total length of header structure known to the sender */ | |
80 | unsigned int header_size; | |
81 | /* properties string buffer */ | |
82 | unsigned int properties_off; | |
83 | unsigned int properties_len; | |
84 | /* | |
85 | * hashes of primary device properties strings, to let libudev subscribers | |
86 | * use in-kernel socket filters; values need to be stored in network order | |
87 | */ | |
88 | unsigned int filter_subsystem_hash; | |
89 | unsigned int filter_devtype_hash; | |
90 | unsigned int filter_tag_bloom_hi; | |
91 | unsigned int filter_tag_bloom_lo; | |
e14bdd88 KS |
92 | }; |
93 | ||
94 | static struct udev_monitor *udev_monitor_new(struct udev *udev) | |
95 | { | |
912541b0 KS |
96 | struct udev_monitor *udev_monitor; |
97 | ||
98 | udev_monitor = calloc(1, sizeof(struct udev_monitor)); | |
99 | if (udev_monitor == NULL) | |
100 | return NULL; | |
101 | udev_monitor->refcount = 1; | |
102 | udev_monitor->udev = udev; | |
103 | udev_list_init(udev, &udev_monitor->filter_subsystem_list, false); | |
104 | udev_list_init(udev, &udev_monitor->filter_tag_list, true); | |
105 | return udev_monitor; | |
e14bdd88 KS |
106 | } |
107 | ||
7459bcdc | 108 | struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) |
1c7047ea | 109 | { |
912541b0 KS |
110 | struct udev_monitor *udev_monitor; |
111 | unsigned int group; | |
112 | ||
113 | if (udev == NULL) | |
114 | return NULL; | |
115 | ||
116 | if (name == NULL) | |
117 | group = UDEV_MONITOR_NONE; | |
118 | else if (strcmp(name, "udev") == 0) | |
119 | group = UDEV_MONITOR_UDEV; | |
120 | else if (strcmp(name, "kernel") == 0) | |
121 | group = UDEV_MONITOR_KERNEL; | |
122 | else | |
123 | return NULL; | |
124 | ||
125 | udev_monitor = udev_monitor_new(udev); | |
126 | if (udev_monitor == NULL) | |
127 | return NULL; | |
128 | ||
129 | if (fd < 0) { | |
130 | udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); | |
131 | if (udev_monitor->sock == -1) { | |
c8f8394a | 132 | udev_err(udev, "error getting socket: %m\n"); |
912541b0 KS |
133 | free(udev_monitor); |
134 | return NULL; | |
135 | } | |
136 | } else { | |
137 | udev_monitor->bound = true; | |
138 | udev_monitor->sock = fd; | |
139 | } | |
140 | ||
b49d9b50 KS |
141 | udev_monitor->snl.nl.nl_family = AF_NETLINK; |
142 | udev_monitor->snl.nl.nl_groups = group; | |
912541b0 KS |
143 | |
144 | /* default destination for sending */ | |
b49d9b50 KS |
145 | udev_monitor->snl_destination.nl.nl_family = AF_NETLINK; |
146 | udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV; | |
912541b0 | 147 | |
912541b0 | 148 | return udev_monitor; |
1c7047ea KS |
149 | } |
150 | ||
7459bcdc KS |
151 | /** |
152 | * udev_monitor_new_from_netlink: | |
153 | * @udev: udev library context | |
154 | * @name: name of event source | |
155 | * | |
156 | * Create new udev monitor and connect to a specified event | |
157 | * source. Valid sources identifiers are "udev" and "kernel". | |
158 | * | |
159 | * Applications should usually not connect directly to the | |
160 | * "kernel" events, because the devices might not be useable | |
161 | * at that time, before udev has configured them, and created | |
50579295 KS |
162 | * device nodes. Accessing devices at the same time as udev, |
163 | * might result in unpredictable behavior. The "udev" events | |
164 | * are sent out after udev has finished its event processing, | |
165 | * all rules have been processed, and needed device nodes are | |
166 | * created. | |
7459bcdc KS |
167 | * |
168 | * The initial refcount is 1, and needs to be decremented to | |
169 | * release the resources of the udev monitor. | |
170 | * | |
171 | * Returns: a new udev monitor, or #NULL, in case of an error | |
172 | **/ | |
54cf0b7f | 173 | _public_ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) |
7459bcdc | 174 | { |
912541b0 | 175 | return udev_monitor_new_from_netlink_fd(udev, name, -1); |
7459bcdc KS |
176 | } |
177 | ||
e14bdd88 | 178 | static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i, |
912541b0 | 179 | unsigned short code, unsigned int data) |
e14bdd88 | 180 | { |
912541b0 | 181 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 182 | |
912541b0 KS |
183 | ins->code = code; |
184 | ins->k = data; | |
185 | (*i)++; | |
e14bdd88 KS |
186 | } |
187 | ||
188 | static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i, | |
912541b0 KS |
189 | unsigned short code, unsigned int data, |
190 | unsigned short jt, unsigned short jf) | |
e14bdd88 | 191 | { |
912541b0 | 192 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 193 | |
912541b0 KS |
194 | ins->code = code; |
195 | ins->jt = jt; | |
196 | ins->jf = jf; | |
197 | ins->k = data; | |
198 | (*i)++; | |
e14bdd88 KS |
199 | } |
200 | ||
ce1d6d7f KS |
201 | /** |
202 | * udev_monitor_filter_update: | |
203 | * @udev_monitor: monitor | |
204 | * | |
50579295 KS |
205 | * Update the installed socket filter. This is only needed, |
206 | * if the filter was removed or changed. | |
ce1d6d7f KS |
207 | * |
208 | * Returns: 0 on success, otherwise a negative error value. | |
209 | */ | |
54cf0b7f | 210 | _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor) |
e14bdd88 | 211 | { |
912541b0 KS |
212 | struct sock_filter ins[512]; |
213 | struct sock_fprog filter; | |
214 | unsigned int i; | |
215 | struct udev_list_entry *list_entry; | |
216 | int err; | |
217 | ||
218 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL && | |
219 | udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) | |
220 | return 0; | |
221 | ||
222 | memset(ins, 0x00, sizeof(ins)); | |
223 | i = 0; | |
224 | ||
225 | /* load magic in A */ | |
226 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic)); | |
227 | /* jump if magic matches */ | |
228 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); | |
229 | /* wrong magic, pass packet */ | |
230 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
231 | ||
232 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) { | |
233 | int tag_matches; | |
234 | ||
235 | /* count tag matches, to calculate end of tag match block */ | |
236 | tag_matches = 0; | |
237 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) | |
238 | tag_matches++; | |
239 | ||
240 | /* add all tags matches */ | |
241 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
242 | uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
243 | uint32_t tag_bloom_hi = tag_bloom_bits >> 32; | |
244 | uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; | |
245 | ||
246 | /* load device bloom bits in A */ | |
247 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi)); | |
248 | /* clear bits (tag bits & bloom bits) */ | |
249 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); | |
250 | /* jump to next tag if it does not match */ | |
251 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); | |
252 | ||
253 | /* load device bloom bits in A */ | |
254 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo)); | |
255 | /* clear bits (tag bits & bloom bits) */ | |
256 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); | |
257 | /* jump behind end of tag match block if tag matches */ | |
258 | tag_matches--; | |
259 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); | |
260 | } | |
261 | ||
262 | /* nothing matched, drop packet */ | |
263 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
264 | } | |
265 | ||
266 | /* add all subsystem matches */ | |
267 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) { | |
268 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
269 | unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry)); | |
270 | ||
271 | /* load device subsystem value in A */ | |
272 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash)); | |
273 | if (udev_list_entry_get_value(list_entry) == NULL) { | |
274 | /* jump if subsystem does not match */ | |
275 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
276 | } else { | |
277 | /* jump if subsystem does not match */ | |
278 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); | |
279 | ||
280 | /* load device devtype value in A */ | |
281 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash)); | |
282 | /* jump if value does not match */ | |
283 | hash = util_string_hash32(udev_list_entry_get_value(list_entry)); | |
284 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
285 | } | |
286 | ||
287 | /* matched, pass packet */ | |
288 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
289 | ||
8fef0ff2 | 290 | if (i+1 >= ELEMENTSOF(ins)) |
912541b0 KS |
291 | return -1; |
292 | } | |
293 | ||
294 | /* nothing matched, drop packet */ | |
295 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
296 | } | |
297 | ||
298 | /* matched, pass packet */ | |
299 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
300 | ||
301 | /* install filter */ | |
302 | memset(&filter, 0x00, sizeof(filter)); | |
303 | filter.len = i; | |
304 | filter.filter = ins; | |
305 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
306 | return err; | |
e14bdd88 KS |
307 | } |
308 | ||
1e03b754 KS |
309 | int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
310 | { | |
b49d9b50 | 311 | udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid; |
912541b0 | 312 | return 0; |
1e03b754 | 313 | } |
ce1d6d7f KS |
314 | /** |
315 | * udev_monitor_enable_receiving: | |
316 | * @udev_monitor: the monitor which should receive events | |
317 | * | |
318 | * Binds the @udev_monitor socket to the event source. | |
319 | * | |
320 | * Returns: 0 on success, otherwise a negative error value. | |
321 | */ | |
54cf0b7f | 322 | _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
d59f11e1 | 323 | { |
912541b0 KS |
324 | int err = 0; |
325 | const int on = 1; | |
326 | ||
b49d9b50 | 327 | if (udev_monitor->snl.nl.nl_family == 0) |
912541b0 | 328 | return -EINVAL; |
2d13da88 KS |
329 | |
330 | udev_monitor_filter_update(udev_monitor); | |
331 | ||
332 | if (!udev_monitor->bound) { | |
333 | err = bind(udev_monitor->sock, | |
b49d9b50 | 334 | &udev_monitor->snl.sa, sizeof(struct sockaddr_nl)); |
2d13da88 KS |
335 | if (err == 0) |
336 | udev_monitor->bound = true; | |
912541b0 KS |
337 | } |
338 | ||
2d13da88 | 339 | if (err >= 0) { |
b49d9b50 | 340 | union sockaddr_union snl; |
2d13da88 KS |
341 | socklen_t addrlen; |
342 | ||
343 | /* | |
344 | * get the address the kernel has assigned us | |
345 | * it is usually, but not necessarily the pid | |
346 | */ | |
347 | addrlen = sizeof(struct sockaddr_nl); | |
b49d9b50 | 348 | err = getsockname(udev_monitor->sock, &snl.sa, &addrlen); |
2d13da88 | 349 | if (err == 0) |
b49d9b50 | 350 | udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid; |
2d13da88 | 351 | } else { |
c8f8394a | 352 | udev_err(udev_monitor->udev, "bind failed: %m\n"); |
912541b0 KS |
353 | return err; |
354 | } | |
355 | ||
356 | /* enable receiving of sender credentials */ | |
357 | setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); | |
358 | return 0; | |
ba6929f6 KS |
359 | } |
360 | ||
f712894d KS |
361 | /** |
362 | * udev_monitor_set_receive_buffer_size: | |
363 | * @udev_monitor: the monitor which should receive events | |
364 | * @size: the size in bytes | |
365 | * | |
366 | * Set the size of the kernel socket buffer. This call needs the | |
367 | * appropriate privileges to succeed. | |
368 | * | |
369 | * Returns: 0 on success, otherwise -1 on error. | |
370 | */ | |
54cf0b7f | 371 | _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
cb25a958 | 372 | { |
912541b0 KS |
373 | if (udev_monitor == NULL) |
374 | return -1; | |
375 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)); | |
cb25a958 KS |
376 | } |
377 | ||
1e03b754 KS |
378 | int udev_monitor_disconnect(struct udev_monitor *udev_monitor) |
379 | { | |
912541b0 | 380 | int err; |
1e03b754 | 381 | |
912541b0 KS |
382 | err = close(udev_monitor->sock); |
383 | udev_monitor->sock = -1; | |
384 | return err; | |
1e03b754 KS |
385 | } |
386 | ||
7d8787b3 KS |
387 | /** |
388 | * udev_monitor_ref: | |
389 | * @udev_monitor: udev monitor | |
390 | * | |
391 | * Take a reference of a udev monitor. | |
392 | * | |
393 | * Returns: the passed udev monitor | |
394 | **/ | |
54cf0b7f | 395 | _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor) |
ba6929f6 | 396 | { |
912541b0 KS |
397 | if (udev_monitor == NULL) |
398 | return NULL; | |
399 | udev_monitor->refcount++; | |
400 | return udev_monitor; | |
ba6929f6 KS |
401 | } |
402 | ||
7d8787b3 KS |
403 | /** |
404 | * udev_monitor_unref: | |
405 | * @udev_monitor: udev monitor | |
406 | * | |
ff109b8d | 407 | * Drop a reference of a udev monitor. If the refcount reaches zero, |
be7de409 | 408 | * the bound socket will be closed, and the resources of the monitor |
7d8787b3 KS |
409 | * will be released. |
410 | * | |
c1959569 | 411 | * Returns: the passed udev monitor if it has still an active reference, or #NULL otherwise. |
7d8787b3 | 412 | **/ |
20bbd54f | 413 | _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor) |
ba6929f6 | 414 | { |
912541b0 | 415 | if (udev_monitor == NULL) |
20bbd54f | 416 | return NULL; |
912541b0 KS |
417 | udev_monitor->refcount--; |
418 | if (udev_monitor->refcount > 0) | |
20bbd54f | 419 | return udev_monitor; |
912541b0 KS |
420 | if (udev_monitor->sock >= 0) |
421 | close(udev_monitor->sock); | |
422 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); | |
423 | udev_list_cleanup(&udev_monitor->filter_tag_list); | |
912541b0 | 424 | free(udev_monitor); |
20bbd54f | 425 | return NULL; |
ba6929f6 KS |
426 | } |
427 | ||
7d8787b3 KS |
428 | /** |
429 | * udev_monitor_get_udev: | |
430 | * @udev_monitor: udev monitor | |
431 | * | |
b98fd840 | 432 | * Retrieve the udev library context the monitor was created with. |
7d8787b3 KS |
433 | * |
434 | * Returns: the udev library context | |
435 | **/ | |
54cf0b7f | 436 | _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor) |
ba6929f6 | 437 | { |
912541b0 KS |
438 | if (udev_monitor == NULL) |
439 | return NULL; | |
440 | return udev_monitor->udev; | |
ba6929f6 KS |
441 | } |
442 | ||
7d8787b3 KS |
443 | /** |
444 | * udev_monitor_get_fd: | |
445 | * @udev_monitor: udev monitor | |
446 | * | |
447 | * Retrieve the socket file descriptor associated with the monitor. | |
448 | * | |
449 | * Returns: the socket file descriptor | |
450 | **/ | |
54cf0b7f | 451 | _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
ba6929f6 | 452 | { |
912541b0 KS |
453 | if (udev_monitor == NULL) |
454 | return -1; | |
455 | return udev_monitor->sock; | |
ba6929f6 KS |
456 | } |
457 | ||
e14bdd88 KS |
458 | static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device) |
459 | { | |
912541b0 KS |
460 | struct udev_list_entry *list_entry; |
461 | ||
462 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL) | |
463 | goto tag; | |
464 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
465 | const char *subsys = udev_list_entry_get_name(list_entry); | |
466 | const char *dsubsys = udev_device_get_subsystem(udev_device); | |
467 | const char *devtype; | |
468 | const char *ddevtype; | |
469 | ||
470 | if (strcmp(dsubsys, subsys) != 0) | |
471 | continue; | |
472 | ||
473 | devtype = udev_list_entry_get_value(list_entry); | |
474 | if (devtype == NULL) | |
475 | goto tag; | |
476 | ddevtype = udev_device_get_devtype(udev_device); | |
477 | if (ddevtype == NULL) | |
478 | continue; | |
479 | if (strcmp(ddevtype, devtype) == 0) | |
480 | goto tag; | |
481 | } | |
482 | return 0; | |
28460195 KS |
483 | |
484 | tag: | |
912541b0 KS |
485 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) |
486 | return 1; | |
487 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
488 | const char *tag = udev_list_entry_get_name(list_entry); | |
489 | ||
490 | if (udev_device_has_tag(udev_device, tag)) | |
491 | return 1; | |
492 | } | |
493 | return 0; | |
e14bdd88 KS |
494 | } |
495 | ||
7d8787b3 | 496 | /** |
d59f11e1 | 497 | * udev_monitor_receive_device: |
7d8787b3 KS |
498 | * @udev_monitor: udev monitor |
499 | * | |
d59f11e1 | 500 | * Receive data from the udev monitor socket, allocate a new udev |
b98fd840 | 501 | * device, fill in the received data, and return the device. |
7d8787b3 | 502 | * |
50579295 | 503 | * Only socket connections with uid=0 are accepted. |
7d8787b3 | 504 | * |
b30b4260 KS |
505 | * The monitor socket is by default set to NONBLOCK. A variant of poll() on |
506 | * the file descriptor returned by udev_monitor_get_fd() should to be used to | |
507 | * wake up when new devices arrive, or alternatively the file descriptor | |
508 | * switched into blocking mode. | |
509 | * | |
7d8787b3 | 510 | * The initial refcount is 1, and needs to be decremented to |
be7de409 | 511 | * release the resources of the udev device. |
7d8787b3 KS |
512 | * |
513 | * Returns: a new udev device, or #NULL, in case of an error | |
514 | **/ | |
54cf0b7f | 515 | _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor) |
ba6929f6 | 516 | { |
912541b0 KS |
517 | struct udev_device *udev_device; |
518 | struct msghdr smsg; | |
519 | struct iovec iov; | |
520 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
521 | struct cmsghdr *cmsg; | |
b49d9b50 | 522 | union sockaddr_union snl; |
912541b0 KS |
523 | struct ucred *cred; |
524 | char buf[8192]; | |
525 | ssize_t buflen; | |
526 | ssize_t bufpos; | |
527 | struct udev_monitor_netlink_header *nlh; | |
ba6929f6 | 528 | |
e14bdd88 | 529 | retry: |
912541b0 KS |
530 | if (udev_monitor == NULL) |
531 | return NULL; | |
912541b0 KS |
532 | iov.iov_base = &buf; |
533 | iov.iov_len = sizeof(buf); | |
534 | memset (&smsg, 0x00, sizeof(struct msghdr)); | |
535 | smsg.msg_iov = &iov; | |
536 | smsg.msg_iovlen = 1; | |
537 | smsg.msg_control = cred_msg; | |
538 | smsg.msg_controllen = sizeof(cred_msg); | |
539 | ||
b49d9b50 | 540 | if (udev_monitor->snl.nl.nl_family != 0) { |
912541b0 KS |
541 | smsg.msg_name = &snl; |
542 | smsg.msg_namelen = sizeof(snl); | |
543 | } | |
544 | ||
545 | buflen = recvmsg(udev_monitor->sock, &smsg, 0); | |
546 | if (buflen < 0) { | |
547 | if (errno != EINTR) | |
c8f8394a | 548 | udev_dbg(udev_monitor->udev, "unable to receive message\n"); |
912541b0 KS |
549 | return NULL; |
550 | } | |
551 | ||
552 | if (buflen < 32 || (size_t)buflen >= sizeof(buf)) { | |
c8f8394a | 553 | udev_dbg(udev_monitor->udev, "invalid message length\n"); |
912541b0 KS |
554 | return NULL; |
555 | } | |
556 | ||
b49d9b50 KS |
557 | if (udev_monitor->snl.nl.nl_family != 0) { |
558 | if (snl.nl.nl_groups == 0) { | |
912541b0 | 559 | /* unicast message, check if we trust the sender */ |
b49d9b50 KS |
560 | if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 || |
561 | snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) { | |
c8f8394a | 562 | udev_dbg(udev_monitor->udev, "unicast netlink message ignored\n"); |
912541b0 KS |
563 | return NULL; |
564 | } | |
b49d9b50 KS |
565 | } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) { |
566 | if (snl.nl.nl_pid > 0) { | |
c8f8394a | 567 | udev_dbg(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n", |
b49d9b50 | 568 | snl.nl.nl_pid); |
912541b0 KS |
569 | return NULL; |
570 | } | |
571 | } | |
572 | } | |
573 | ||
574 | cmsg = CMSG_FIRSTHDR(&smsg); | |
575 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
c8f8394a | 576 | udev_dbg(udev_monitor->udev, "no sender credentials received, message ignored\n"); |
912541b0 KS |
577 | return NULL; |
578 | } | |
579 | ||
580 | cred = (struct ucred *)CMSG_DATA(cmsg); | |
581 | if (cred->uid != 0) { | |
c8f8394a | 582 | udev_dbg(udev_monitor->udev, "sender uid=%d, message ignored\n", cred->uid); |
912541b0 KS |
583 | return NULL; |
584 | } | |
585 | ||
586 | if (memcmp(buf, "libudev", 8) == 0) { | |
587 | /* udev message needs proper version magic */ | |
588 | nlh = (struct udev_monitor_netlink_header *) buf; | |
589 | if (nlh->magic != htonl(UDEV_MONITOR_MAGIC)) { | |
c8f8394a | 590 | udev_err(udev_monitor->udev, "unrecognized message signature (%x != %x)\n", |
912541b0 KS |
591 | nlh->magic, htonl(UDEV_MONITOR_MAGIC)); |
592 | return NULL; | |
593 | } | |
ee56538f | 594 | if (nlh->properties_off+32 > (size_t)buflen) |
912541b0 KS |
595 | return NULL; |
596 | bufpos = nlh->properties_off; | |
597 | } else { | |
598 | /* kernel message with header */ | |
599 | bufpos = strlen(buf) + 1; | |
600 | if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { | |
c8f8394a | 601 | udev_dbg(udev_monitor->udev, "invalid message length\n"); |
912541b0 KS |
602 | return NULL; |
603 | } | |
604 | ||
605 | /* check message header */ | |
606 | if (strstr(buf, "@/") == NULL) { | |
c8f8394a | 607 | udev_dbg(udev_monitor->udev, "unrecognized message header\n"); |
912541b0 KS |
608 | return NULL; |
609 | } | |
610 | } | |
611 | ||
612 | udev_device = udev_device_new(udev_monitor->udev); | |
613 | if (udev_device == NULL) | |
614 | return NULL; | |
615 | udev_device_set_info_loaded(udev_device); | |
616 | ||
617 | while (bufpos < buflen) { | |
618 | char *key; | |
619 | size_t keylen; | |
620 | ||
621 | key = &buf[bufpos]; | |
622 | keylen = strlen(key); | |
623 | if (keylen == 0) | |
624 | break; | |
625 | bufpos += keylen + 1; | |
626 | udev_device_add_property_from_string_parse(udev_device, key); | |
627 | } | |
628 | ||
629 | if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) { | |
c8f8394a | 630 | udev_dbg(udev_monitor->udev, "missing values, invalid device\n"); |
912541b0 KS |
631 | udev_device_unref(udev_device); |
632 | return NULL; | |
633 | } | |
634 | ||
635 | /* skip device, if it does not pass the current filter */ | |
636 | if (!passes_filter(udev_monitor, udev_device)) { | |
637 | struct pollfd pfd[1]; | |
638 | int rc; | |
639 | ||
640 | udev_device_unref(udev_device); | |
641 | ||
642 | /* if something is queued, get next device */ | |
643 | pfd[0].fd = udev_monitor->sock; | |
644 | pfd[0].events = POLLIN; | |
645 | rc = poll(pfd, 1, 0); | |
646 | if (rc > 0) | |
647 | goto retry; | |
648 | return NULL; | |
649 | } | |
650 | ||
651 | return udev_device; | |
ba6929f6 | 652 | } |
9925ab04 | 653 | |
1e03b754 | 654 | int udev_monitor_send_device(struct udev_monitor *udev_monitor, |
912541b0 | 655 | struct udev_monitor *destination, struct udev_device *udev_device) |
9925ab04 | 656 | { |
912541b0 KS |
657 | const char *buf; |
658 | ssize_t blen; | |
659 | ssize_t count; | |
2d13da88 KS |
660 | struct msghdr smsg; |
661 | struct iovec iov[2]; | |
662 | const char *val; | |
663 | struct udev_monitor_netlink_header nlh; | |
664 | struct udev_list_entry *list_entry; | |
665 | uint64_t tag_bloom_bits; | |
666 | ||
b49d9b50 | 667 | if (udev_monitor->snl.nl.nl_family == 0) |
2d13da88 | 668 | return -EINVAL; |
912541b0 KS |
669 | |
670 | blen = udev_device_get_properties_monitor_buf(udev_device, &buf); | |
671 | if (blen < 32) | |
672 | return -EINVAL; | |
673 | ||
2d13da88 KS |
674 | /* add versioned header */ |
675 | memset(&nlh, 0x00, sizeof(struct udev_monitor_netlink_header)); | |
676 | memcpy(nlh.prefix, "libudev", 8); | |
677 | nlh.magic = htonl(UDEV_MONITOR_MAGIC); | |
678 | nlh.header_size = sizeof(struct udev_monitor_netlink_header); | |
679 | val = udev_device_get_subsystem(udev_device); | |
680 | nlh.filter_subsystem_hash = htonl(util_string_hash32(val)); | |
681 | val = udev_device_get_devtype(udev_device); | |
682 | if (val != NULL) | |
683 | nlh.filter_devtype_hash = htonl(util_string_hash32(val)); | |
684 | iov[0].iov_base = &nlh; | |
685 | iov[0].iov_len = sizeof(struct udev_monitor_netlink_header); | |
686 | ||
687 | /* add tag bloom filter */ | |
688 | tag_bloom_bits = 0; | |
689 | udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device)) | |
690 | tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
691 | if (tag_bloom_bits > 0) { | |
692 | nlh.filter_tag_bloom_hi = htonl(tag_bloom_bits >> 32); | |
693 | nlh.filter_tag_bloom_lo = htonl(tag_bloom_bits & 0xffffffff); | |
912541b0 KS |
694 | } |
695 | ||
2d13da88 KS |
696 | /* add properties list */ |
697 | nlh.properties_off = iov[0].iov_len; | |
698 | nlh.properties_len = blen; | |
699 | iov[1].iov_base = (char *)buf; | |
700 | iov[1].iov_len = blen; | |
912541b0 | 701 | |
2d13da88 KS |
702 | memset(&smsg, 0x00, sizeof(struct msghdr)); |
703 | smsg.msg_iov = iov; | |
704 | smsg.msg_iovlen = 2; | |
705 | /* | |
706 | * Use custom address for target, or the default one. | |
707 | * | |
708 | * If we send to a multicast group, we will get | |
709 | * ECONNREFUSED, which is expected. | |
710 | */ | |
711 | if (destination != NULL) | |
712 | smsg.msg_name = &destination->snl; | |
713 | else | |
714 | smsg.msg_name = &udev_monitor->snl_destination; | |
715 | smsg.msg_namelen = sizeof(struct sockaddr_nl); | |
716 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
c8f8394a | 717 | udev_dbg(udev_monitor->udev, "passed %zi bytes to netlink monitor %p\n", count, udev_monitor); |
2d13da88 | 718 | return count; |
9925ab04 | 719 | } |
e14bdd88 | 720 | |
ce1d6d7f KS |
721 | /** |
722 | * udev_monitor_filter_add_match_subsystem_devtype: | |
723 | * @udev_monitor: the monitor | |
724 | * @subsystem: the subsystem value to match the incoming devices against | |
214a6c79 | 725 | * @devtype: the devtype value to match the incoming devices against |
ce1d6d7f | 726 | * |
50579295 | 727 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
728 | * will usually not be woken up for devices which do not match. |
729 | * | |
ce1d6d7f KS |
730 | * The filter must be installed before the monitor is switched to listening mode. |
731 | * | |
732 | * Returns: 0 on success, otherwise a negative error value. | |
733 | */ | |
54cf0b7f | 734 | _public_ int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype) |
e14bdd88 | 735 | { |
912541b0 KS |
736 | if (udev_monitor == NULL) |
737 | return -EINVAL; | |
738 | if (subsystem == NULL) | |
739 | return -EINVAL; | |
740 | if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL) | |
741 | return -ENOMEM; | |
742 | return 0; | |
e14bdd88 | 743 | } |
08a7a795 | 744 | |
28460195 KS |
745 | /** |
746 | * udev_monitor_filter_add_match_tag: | |
747 | * @udev_monitor: the monitor | |
748 | * @tag: the name of a tag | |
749 | * | |
50579295 | 750 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
751 | * will usually not be woken up for devices which do not match. |
752 | * | |
753 | * The filter must be installed before the monitor is switched to listening mode. | |
754 | * | |
755 | * Returns: 0 on success, otherwise a negative error value. | |
756 | */ | |
54cf0b7f | 757 | _public_ int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag) |
28460195 | 758 | { |
912541b0 KS |
759 | if (udev_monitor == NULL) |
760 | return -EINVAL; | |
761 | if (tag == NULL) | |
762 | return -EINVAL; | |
763 | if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL) | |
764 | return -ENOMEM; | |
765 | return 0; | |
28460195 KS |
766 | } |
767 | ||
ce1d6d7f KS |
768 | /** |
769 | * udev_monitor_filter_remove: | |
770 | * @udev_monitor: monitor | |
771 | * | |
772 | * Remove all filters from monitor. | |
773 | * | |
774 | * Returns: 0 on success, otherwise a negative error value. | |
775 | */ | |
54cf0b7f | 776 | _public_ int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
08a7a795 | 777 | { |
912541b0 | 778 | static struct sock_fprog filter = { 0, NULL }; |
08a7a795 | 779 | |
912541b0 KS |
780 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
781 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
08a7a795 | 782 | } |