]>
Commit | Line | Data |
---|---|---|
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 | ||
7459bcdc | 149 | struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) |
1c7047ea | 150 | { |
912541b0 KS |
151 | struct udev_monitor *udev_monitor; |
152 | unsigned int group; | |
153 | ||
154 | if (udev == NULL) | |
155 | return NULL; | |
156 | ||
157 | if (name == NULL) | |
158 | group = UDEV_MONITOR_NONE; | |
e8a3b2dc KS |
159 | else if (streq(name, "udev")) { |
160 | /* | |
161 | * We do not support subscribing to uevents if no instance of | |
162 | * udev is running. Uevents would otherwise broadcast the | |
163 | * processing data of the host into containers, which is not | |
164 | * desired. | |
165 | * | |
166 | * Containers will currently not get any udev uevents, until | |
167 | * a supporting infrastructure is available. | |
168 | * | |
169 | * We do not set a netlink multicast group here, so the socket | |
170 | * will not receive any messages. | |
171 | */ | |
9ea28c55 | 172 | if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) { |
e8a3b2dc KS |
173 | udev_dbg(udev, "the udev service seems not to be active, disable the monitor\n"); |
174 | group = UDEV_MONITOR_NONE; | |
175 | } else | |
176 | group = UDEV_MONITOR_UDEV; | |
177 | } else if (streq(name, "kernel")) | |
912541b0 KS |
178 | group = UDEV_MONITOR_KERNEL; |
179 | else | |
180 | return NULL; | |
181 | ||
182 | udev_monitor = udev_monitor_new(udev); | |
183 | if (udev_monitor == NULL) | |
184 | return NULL; | |
185 | ||
186 | if (fd < 0) { | |
187 | udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); | |
188 | if (udev_monitor->sock == -1) { | |
c8f8394a | 189 | udev_err(udev, "error getting socket: %m\n"); |
912541b0 KS |
190 | free(udev_monitor); |
191 | return NULL; | |
192 | } | |
193 | } else { | |
194 | udev_monitor->bound = true; | |
195 | udev_monitor->sock = fd; | |
196 | } | |
197 | ||
b49d9b50 KS |
198 | udev_monitor->snl.nl.nl_family = AF_NETLINK; |
199 | udev_monitor->snl.nl.nl_groups = group; | |
912541b0 KS |
200 | |
201 | /* default destination for sending */ | |
b49d9b50 KS |
202 | udev_monitor->snl_destination.nl.nl_family = AF_NETLINK; |
203 | udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV; | |
912541b0 | 204 | |
912541b0 | 205 | return udev_monitor; |
1c7047ea KS |
206 | } |
207 | ||
7459bcdc KS |
208 | /** |
209 | * udev_monitor_new_from_netlink: | |
210 | * @udev: udev library context | |
211 | * @name: name of event source | |
212 | * | |
213 | * Create new udev monitor and connect to a specified event | |
214 | * source. Valid sources identifiers are "udev" and "kernel". | |
215 | * | |
216 | * Applications should usually not connect directly to the | |
217 | * "kernel" events, because the devices might not be useable | |
218 | * at that time, before udev has configured them, and created | |
50579295 KS |
219 | * device nodes. Accessing devices at the same time as udev, |
220 | * might result in unpredictable behavior. The "udev" events | |
221 | * are sent out after udev has finished its event processing, | |
222 | * all rules have been processed, and needed device nodes are | |
223 | * created. | |
7459bcdc KS |
224 | * |
225 | * The initial refcount is 1, and needs to be decremented to | |
226 | * release the resources of the udev monitor. | |
227 | * | |
228 | * Returns: a new udev monitor, or #NULL, in case of an error | |
229 | **/ | |
54cf0b7f | 230 | _public_ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) |
7459bcdc | 231 | { |
912541b0 | 232 | return udev_monitor_new_from_netlink_fd(udev, name, -1); |
7459bcdc KS |
233 | } |
234 | ||
e14bdd88 | 235 | static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i, |
912541b0 | 236 | unsigned short code, unsigned int data) |
e14bdd88 | 237 | { |
912541b0 | 238 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 239 | |
912541b0 KS |
240 | ins->code = code; |
241 | ins->k = data; | |
242 | (*i)++; | |
e14bdd88 KS |
243 | } |
244 | ||
245 | static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i, | |
912541b0 KS |
246 | unsigned short code, unsigned int data, |
247 | unsigned short jt, unsigned short jf) | |
e14bdd88 | 248 | { |
912541b0 | 249 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 250 | |
912541b0 KS |
251 | ins->code = code; |
252 | ins->jt = jt; | |
253 | ins->jf = jf; | |
254 | ins->k = data; | |
255 | (*i)++; | |
e14bdd88 KS |
256 | } |
257 | ||
ce1d6d7f KS |
258 | /** |
259 | * udev_monitor_filter_update: | |
260 | * @udev_monitor: monitor | |
261 | * | |
50579295 KS |
262 | * Update the installed socket filter. This is only needed, |
263 | * if the filter was removed or changed. | |
ce1d6d7f KS |
264 | * |
265 | * Returns: 0 on success, otherwise a negative error value. | |
266 | */ | |
54cf0b7f | 267 | _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor) |
e14bdd88 | 268 | { |
912541b0 KS |
269 | struct sock_filter ins[512]; |
270 | struct sock_fprog filter; | |
271 | unsigned int i; | |
272 | struct udev_list_entry *list_entry; | |
273 | int err; | |
274 | ||
275 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL && | |
276 | udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) | |
277 | return 0; | |
278 | ||
29804cc1 | 279 | memzero(ins, sizeof(ins)); |
912541b0 KS |
280 | i = 0; |
281 | ||
282 | /* load magic in A */ | |
283 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic)); | |
284 | /* jump if magic matches */ | |
285 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); | |
286 | /* wrong magic, pass packet */ | |
287 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
288 | ||
289 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) { | |
290 | int tag_matches; | |
291 | ||
292 | /* count tag matches, to calculate end of tag match block */ | |
293 | tag_matches = 0; | |
294 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) | |
295 | tag_matches++; | |
296 | ||
297 | /* add all tags matches */ | |
298 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
299 | uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
300 | uint32_t tag_bloom_hi = tag_bloom_bits >> 32; | |
301 | uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; | |
302 | ||
303 | /* load device bloom bits in A */ | |
304 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi)); | |
305 | /* clear bits (tag bits & bloom bits) */ | |
306 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); | |
307 | /* jump to next tag if it does not match */ | |
308 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); | |
309 | ||
310 | /* load device bloom bits in A */ | |
311 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo)); | |
312 | /* clear bits (tag bits & bloom bits) */ | |
313 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); | |
314 | /* jump behind end of tag match block if tag matches */ | |
315 | tag_matches--; | |
316 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); | |
317 | } | |
318 | ||
319 | /* nothing matched, drop packet */ | |
320 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
321 | } | |
322 | ||
323 | /* add all subsystem matches */ | |
324 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) { | |
325 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
326 | unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry)); | |
327 | ||
328 | /* load device subsystem value in A */ | |
329 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash)); | |
330 | if (udev_list_entry_get_value(list_entry) == NULL) { | |
331 | /* jump if subsystem does not match */ | |
332 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
333 | } else { | |
334 | /* jump if subsystem does not match */ | |
335 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); | |
336 | ||
337 | /* load device devtype value in A */ | |
338 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash)); | |
339 | /* jump if value does not match */ | |
340 | hash = util_string_hash32(udev_list_entry_get_value(list_entry)); | |
341 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
342 | } | |
343 | ||
344 | /* matched, pass packet */ | |
345 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
346 | ||
8fef0ff2 | 347 | if (i+1 >= ELEMENTSOF(ins)) |
994e0234 | 348 | return -E2BIG; |
912541b0 KS |
349 | } |
350 | ||
351 | /* nothing matched, drop packet */ | |
352 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
353 | } | |
354 | ||
355 | /* matched, pass packet */ | |
356 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
357 | ||
358 | /* install filter */ | |
29804cc1 | 359 | memzero(&filter, sizeof(filter)); |
912541b0 KS |
360 | filter.len = i; |
361 | filter.filter = ins; | |
362 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
994e0234 | 363 | return err < 0 ? -errno : 0; |
e14bdd88 KS |
364 | } |
365 | ||
1e03b754 KS |
366 | int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
367 | { | |
b49d9b50 | 368 | udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid; |
912541b0 | 369 | return 0; |
1e03b754 | 370 | } |
ce1d6d7f KS |
371 | /** |
372 | * udev_monitor_enable_receiving: | |
373 | * @udev_monitor: the monitor which should receive events | |
374 | * | |
375 | * Binds the @udev_monitor socket to the event source. | |
376 | * | |
377 | * Returns: 0 on success, otherwise a negative error value. | |
378 | */ | |
54cf0b7f | 379 | _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
d59f11e1 | 380 | { |
912541b0 KS |
381 | int err = 0; |
382 | const int on = 1; | |
383 | ||
2d13da88 KS |
384 | udev_monitor_filter_update(udev_monitor); |
385 | ||
386 | if (!udev_monitor->bound) { | |
387 | err = bind(udev_monitor->sock, | |
b49d9b50 | 388 | &udev_monitor->snl.sa, sizeof(struct sockaddr_nl)); |
2d13da88 KS |
389 | if (err == 0) |
390 | udev_monitor->bound = true; | |
912541b0 KS |
391 | } |
392 | ||
2d13da88 | 393 | if (err >= 0) { |
b49d9b50 | 394 | union sockaddr_union snl; |
2d13da88 KS |
395 | socklen_t addrlen; |
396 | ||
397 | /* | |
398 | * get the address the kernel has assigned us | |
399 | * it is usually, but not necessarily the pid | |
400 | */ | |
401 | addrlen = sizeof(struct sockaddr_nl); | |
b49d9b50 | 402 | err = getsockname(udev_monitor->sock, &snl.sa, &addrlen); |
2d13da88 | 403 | if (err == 0) |
b49d9b50 | 404 | udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid; |
2d13da88 | 405 | } else { |
c8f8394a | 406 | udev_err(udev_monitor->udev, "bind failed: %m\n"); |
994e0234 | 407 | return -errno; |
912541b0 KS |
408 | } |
409 | ||
410 | /* enable receiving of sender credentials */ | |
411 | setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); | |
412 | return 0; | |
ba6929f6 KS |
413 | } |
414 | ||
f712894d KS |
415 | /** |
416 | * udev_monitor_set_receive_buffer_size: | |
417 | * @udev_monitor: the monitor which should receive events | |
418 | * @size: the size in bytes | |
419 | * | |
420 | * Set the size of the kernel socket buffer. This call needs the | |
421 | * appropriate privileges to succeed. | |
422 | * | |
423 | * Returns: 0 on success, otherwise -1 on error. | |
424 | */ | |
54cf0b7f | 425 | _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
cb25a958 | 426 | { |
912541b0 | 427 | if (udev_monitor == NULL) |
994e0234 | 428 | return -EINVAL; |
912541b0 | 429 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)); |
cb25a958 KS |
430 | } |
431 | ||
1e03b754 KS |
432 | int udev_monitor_disconnect(struct udev_monitor *udev_monitor) |
433 | { | |
912541b0 | 434 | int err; |
1e03b754 | 435 | |
912541b0 KS |
436 | err = close(udev_monitor->sock); |
437 | udev_monitor->sock = -1; | |
994e0234 | 438 | return err < 0 ? -errno : 0; |
1e03b754 KS |
439 | } |
440 | ||
7d8787b3 KS |
441 | /** |
442 | * udev_monitor_ref: | |
443 | * @udev_monitor: udev monitor | |
444 | * | |
445 | * Take a reference of a udev monitor. | |
446 | * | |
447 | * Returns: the passed udev monitor | |
448 | **/ | |
54cf0b7f | 449 | _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor) |
ba6929f6 | 450 | { |
912541b0 KS |
451 | if (udev_monitor == NULL) |
452 | return NULL; | |
453 | udev_monitor->refcount++; | |
454 | return udev_monitor; | |
ba6929f6 KS |
455 | } |
456 | ||
7d8787b3 KS |
457 | /** |
458 | * udev_monitor_unref: | |
459 | * @udev_monitor: udev monitor | |
460 | * | |
ff109b8d | 461 | * Drop a reference of a udev monitor. If the refcount reaches zero, |
be7de409 | 462 | * the bound socket will be closed, and the resources of the monitor |
7d8787b3 KS |
463 | * will be released. |
464 | * | |
725d7e6c | 465 | * Returns: #NULL |
7d8787b3 | 466 | **/ |
20bbd54f | 467 | _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor) |
ba6929f6 | 468 | { |
912541b0 | 469 | if (udev_monitor == NULL) |
20bbd54f | 470 | return NULL; |
912541b0 KS |
471 | udev_monitor->refcount--; |
472 | if (udev_monitor->refcount > 0) | |
725d7e6c | 473 | return NULL; |
912541b0 KS |
474 | if (udev_monitor->sock >= 0) |
475 | close(udev_monitor->sock); | |
476 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); | |
477 | udev_list_cleanup(&udev_monitor->filter_tag_list); | |
912541b0 | 478 | free(udev_monitor); |
20bbd54f | 479 | return NULL; |
ba6929f6 KS |
480 | } |
481 | ||
7d8787b3 KS |
482 | /** |
483 | * udev_monitor_get_udev: | |
484 | * @udev_monitor: udev monitor | |
485 | * | |
b98fd840 | 486 | * Retrieve the udev library context the monitor was created with. |
7d8787b3 KS |
487 | * |
488 | * Returns: the udev library context | |
489 | **/ | |
54cf0b7f | 490 | _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor) |
ba6929f6 | 491 | { |
912541b0 KS |
492 | if (udev_monitor == NULL) |
493 | return NULL; | |
494 | return udev_monitor->udev; | |
ba6929f6 KS |
495 | } |
496 | ||
7d8787b3 KS |
497 | /** |
498 | * udev_monitor_get_fd: | |
499 | * @udev_monitor: udev monitor | |
500 | * | |
501 | * Retrieve the socket file descriptor associated with the monitor. | |
502 | * | |
503 | * Returns: the socket file descriptor | |
504 | **/ | |
54cf0b7f | 505 | _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
ba6929f6 | 506 | { |
912541b0 | 507 | if (udev_monitor == NULL) |
994e0234 | 508 | return -EINVAL; |
912541b0 | 509 | return udev_monitor->sock; |
ba6929f6 KS |
510 | } |
511 | ||
e14bdd88 KS |
512 | static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device) |
513 | { | |
912541b0 KS |
514 | struct udev_list_entry *list_entry; |
515 | ||
516 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL) | |
517 | goto tag; | |
518 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
519 | const char *subsys = udev_list_entry_get_name(list_entry); | |
520 | const char *dsubsys = udev_device_get_subsystem(udev_device); | |
521 | const char *devtype; | |
522 | const char *ddevtype; | |
523 | ||
090be865 | 524 | if (!streq(dsubsys, subsys)) |
912541b0 KS |
525 | continue; |
526 | ||
527 | devtype = udev_list_entry_get_value(list_entry); | |
528 | if (devtype == NULL) | |
529 | goto tag; | |
530 | ddevtype = udev_device_get_devtype(udev_device); | |
531 | if (ddevtype == NULL) | |
532 | continue; | |
090be865 | 533 | if (streq(ddevtype, devtype)) |
912541b0 KS |
534 | goto tag; |
535 | } | |
536 | return 0; | |
28460195 KS |
537 | |
538 | tag: | |
912541b0 KS |
539 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) |
540 | return 1; | |
541 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
542 | const char *tag = udev_list_entry_get_name(list_entry); | |
543 | ||
544 | if (udev_device_has_tag(udev_device, tag)) | |
545 | return 1; | |
546 | } | |
547 | return 0; | |
e14bdd88 KS |
548 | } |
549 | ||
7d8787b3 | 550 | /** |
d59f11e1 | 551 | * udev_monitor_receive_device: |
7d8787b3 KS |
552 | * @udev_monitor: udev monitor |
553 | * | |
d59f11e1 | 554 | * Receive data from the udev monitor socket, allocate a new udev |
b98fd840 | 555 | * device, fill in the received data, and return the device. |
7d8787b3 | 556 | * |
50579295 | 557 | * Only socket connections with uid=0 are accepted. |
7d8787b3 | 558 | * |
b30b4260 KS |
559 | * The monitor socket is by default set to NONBLOCK. A variant of poll() on |
560 | * the file descriptor returned by udev_monitor_get_fd() should to be used to | |
561 | * wake up when new devices arrive, or alternatively the file descriptor | |
562 | * switched into blocking mode. | |
563 | * | |
7d8787b3 | 564 | * The initial refcount is 1, and needs to be decremented to |
be7de409 | 565 | * release the resources of the udev device. |
7d8787b3 KS |
566 | * |
567 | * Returns: a new udev device, or #NULL, in case of an error | |
568 | **/ | |
54cf0b7f | 569 | _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor) |
ba6929f6 | 570 | { |
912541b0 KS |
571 | struct udev_device *udev_device; |
572 | struct msghdr smsg; | |
573 | struct iovec iov; | |
574 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
575 | struct cmsghdr *cmsg; | |
b49d9b50 | 576 | union sockaddr_union snl; |
912541b0 KS |
577 | struct ucred *cred; |
578 | char buf[8192]; | |
579 | ssize_t buflen; | |
580 | ssize_t bufpos; | |
ba6929f6 | 581 | |
e14bdd88 | 582 | retry: |
912541b0 KS |
583 | if (udev_monitor == NULL) |
584 | return NULL; | |
912541b0 KS |
585 | iov.iov_base = &buf; |
586 | iov.iov_len = sizeof(buf); | |
29804cc1 | 587 | memzero(&smsg, sizeof(struct msghdr)); |
912541b0 KS |
588 | smsg.msg_iov = &iov; |
589 | smsg.msg_iovlen = 1; | |
590 | smsg.msg_control = cred_msg; | |
591 | smsg.msg_controllen = sizeof(cred_msg); | |
f6613dd9 KS |
592 | smsg.msg_name = &snl; |
593 | smsg.msg_namelen = sizeof(snl); | |
912541b0 KS |
594 | |
595 | buflen = recvmsg(udev_monitor->sock, &smsg, 0); | |
596 | if (buflen < 0) { | |
597 | if (errno != EINTR) | |
c8f8394a | 598 | udev_dbg(udev_monitor->udev, "unable to receive message\n"); |
912541b0 KS |
599 | return NULL; |
600 | } | |
601 | ||
602 | if (buflen < 32 || (size_t)buflen >= sizeof(buf)) { | |
c8f8394a | 603 | udev_dbg(udev_monitor->udev, "invalid message length\n"); |
912541b0 KS |
604 | return NULL; |
605 | } | |
606 | ||
f6613dd9 KS |
607 | if (snl.nl.nl_groups == 0) { |
608 | /* unicast message, check if we trust the sender */ | |
609 | if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 || | |
610 | snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) { | |
611 | udev_dbg(udev_monitor->udev, "unicast netlink message ignored\n"); | |
612 | return NULL; | |
613 | } | |
614 | } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) { | |
615 | if (snl.nl.nl_pid > 0) { | |
616 | udev_dbg(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n", | |
617 | snl.nl.nl_pid); | |
618 | return NULL; | |
912541b0 KS |
619 | } |
620 | } | |
621 | ||
622 | cmsg = CMSG_FIRSTHDR(&smsg); | |
623 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
c8f8394a | 624 | udev_dbg(udev_monitor->udev, "no sender credentials received, message ignored\n"); |
912541b0 KS |
625 | return NULL; |
626 | } | |
627 | ||
628 | cred = (struct ucred *)CMSG_DATA(cmsg); | |
629 | if (cred->uid != 0) { | |
c8f8394a | 630 | udev_dbg(udev_monitor->udev, "sender uid=%d, message ignored\n", cred->uid); |
912541b0 KS |
631 | return NULL; |
632 | } | |
633 | ||
f6613dd9 KS |
634 | udev_device = udev_device_new(udev_monitor->udev); |
635 | if (udev_device == NULL) | |
636 | return NULL; | |
637 | ||
912541b0 | 638 | if (memcmp(buf, "libudev", 8) == 0) { |
f6613dd9 KS |
639 | struct udev_monitor_netlink_header *nlh; |
640 | ||
912541b0 KS |
641 | /* udev message needs proper version magic */ |
642 | nlh = (struct udev_monitor_netlink_header *) buf; | |
643 | if (nlh->magic != htonl(UDEV_MONITOR_MAGIC)) { | |
c8f8394a | 644 | udev_err(udev_monitor->udev, "unrecognized message signature (%x != %x)\n", |
f6613dd9 KS |
645 | nlh->magic, htonl(UDEV_MONITOR_MAGIC)); |
646 | udev_device_unref(udev_device); | |
912541b0 KS |
647 | return NULL; |
648 | } | |
f6613dd9 KS |
649 | if (nlh->properties_off+32 > (size_t)buflen) { |
650 | udev_device_unref(udev_device); | |
912541b0 | 651 | return NULL; |
f6613dd9 KS |
652 | } |
653 | ||
912541b0 | 654 | bufpos = nlh->properties_off; |
f6613dd9 KS |
655 | |
656 | /* devices received from udev are always initialized */ | |
657 | udev_device_set_is_initialized(udev_device); | |
912541b0 KS |
658 | } else { |
659 | /* kernel message with header */ | |
660 | bufpos = strlen(buf) + 1; | |
661 | if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { | |
c8f8394a | 662 | udev_dbg(udev_monitor->udev, "invalid message length\n"); |
f6613dd9 | 663 | udev_device_unref(udev_device); |
912541b0 KS |
664 | return NULL; |
665 | } | |
666 | ||
667 | /* check message header */ | |
668 | if (strstr(buf, "@/") == NULL) { | |
c8f8394a | 669 | udev_dbg(udev_monitor->udev, "unrecognized message header\n"); |
f6613dd9 | 670 | udev_device_unref(udev_device); |
912541b0 KS |
671 | return NULL; |
672 | } | |
673 | } | |
674 | ||
912541b0 KS |
675 | udev_device_set_info_loaded(udev_device); |
676 | ||
677 | while (bufpos < buflen) { | |
678 | char *key; | |
679 | size_t keylen; | |
680 | ||
681 | key = &buf[bufpos]; | |
682 | keylen = strlen(key); | |
683 | if (keylen == 0) | |
684 | break; | |
685 | bufpos += keylen + 1; | |
686 | udev_device_add_property_from_string_parse(udev_device, key); | |
687 | } | |
688 | ||
689 | if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) { | |
c8f8394a | 690 | udev_dbg(udev_monitor->udev, "missing values, invalid device\n"); |
912541b0 KS |
691 | udev_device_unref(udev_device); |
692 | return NULL; | |
693 | } | |
694 | ||
695 | /* skip device, if it does not pass the current filter */ | |
696 | if (!passes_filter(udev_monitor, udev_device)) { | |
697 | struct pollfd pfd[1]; | |
698 | int rc; | |
699 | ||
700 | udev_device_unref(udev_device); | |
701 | ||
702 | /* if something is queued, get next device */ | |
703 | pfd[0].fd = udev_monitor->sock; | |
704 | pfd[0].events = POLLIN; | |
705 | rc = poll(pfd, 1, 0); | |
706 | if (rc > 0) | |
707 | goto retry; | |
708 | return NULL; | |
709 | } | |
710 | ||
711 | return udev_device; | |
ba6929f6 | 712 | } |
9925ab04 | 713 | |
1e03b754 | 714 | int udev_monitor_send_device(struct udev_monitor *udev_monitor, |
912541b0 | 715 | struct udev_monitor *destination, struct udev_device *udev_device) |
9925ab04 | 716 | { |
912541b0 KS |
717 | const char *buf; |
718 | ssize_t blen; | |
719 | ssize_t count; | |
2d13da88 KS |
720 | struct msghdr smsg; |
721 | struct iovec iov[2]; | |
722 | const char *val; | |
723 | struct udev_monitor_netlink_header nlh; | |
724 | struct udev_list_entry *list_entry; | |
725 | uint64_t tag_bloom_bits; | |
726 | ||
912541b0 KS |
727 | blen = udev_device_get_properties_monitor_buf(udev_device, &buf); |
728 | if (blen < 32) | |
729 | return -EINVAL; | |
730 | ||
2d13da88 | 731 | /* add versioned header */ |
29804cc1 | 732 | memzero(&nlh, sizeof(struct udev_monitor_netlink_header)); |
2d13da88 KS |
733 | memcpy(nlh.prefix, "libudev", 8); |
734 | nlh.magic = htonl(UDEV_MONITOR_MAGIC); | |
735 | nlh.header_size = sizeof(struct udev_monitor_netlink_header); | |
736 | val = udev_device_get_subsystem(udev_device); | |
737 | nlh.filter_subsystem_hash = htonl(util_string_hash32(val)); | |
738 | val = udev_device_get_devtype(udev_device); | |
739 | if (val != NULL) | |
740 | nlh.filter_devtype_hash = htonl(util_string_hash32(val)); | |
741 | iov[0].iov_base = &nlh; | |
742 | iov[0].iov_len = sizeof(struct udev_monitor_netlink_header); | |
743 | ||
744 | /* add tag bloom filter */ | |
745 | tag_bloom_bits = 0; | |
746 | udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device)) | |
747 | tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
748 | if (tag_bloom_bits > 0) { | |
749 | nlh.filter_tag_bloom_hi = htonl(tag_bloom_bits >> 32); | |
750 | nlh.filter_tag_bloom_lo = htonl(tag_bloom_bits & 0xffffffff); | |
912541b0 KS |
751 | } |
752 | ||
2d13da88 KS |
753 | /* add properties list */ |
754 | nlh.properties_off = iov[0].iov_len; | |
755 | nlh.properties_len = blen; | |
756 | iov[1].iov_base = (char *)buf; | |
757 | iov[1].iov_len = blen; | |
912541b0 | 758 | |
29804cc1 | 759 | memzero(&smsg, sizeof(struct msghdr)); |
2d13da88 KS |
760 | smsg.msg_iov = iov; |
761 | smsg.msg_iovlen = 2; | |
762 | /* | |
763 | * Use custom address for target, or the default one. | |
764 | * | |
765 | * If we send to a multicast group, we will get | |
766 | * ECONNREFUSED, which is expected. | |
767 | */ | |
768 | if (destination != NULL) | |
769 | smsg.msg_name = &destination->snl; | |
770 | else | |
771 | smsg.msg_name = &udev_monitor->snl_destination; | |
772 | smsg.msg_namelen = sizeof(struct sockaddr_nl); | |
773 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
c8f8394a | 774 | udev_dbg(udev_monitor->udev, "passed %zi bytes to netlink monitor %p\n", count, udev_monitor); |
2d13da88 | 775 | return count; |
9925ab04 | 776 | } |
e14bdd88 | 777 | |
ce1d6d7f KS |
778 | /** |
779 | * udev_monitor_filter_add_match_subsystem_devtype: | |
780 | * @udev_monitor: the monitor | |
781 | * @subsystem: the subsystem value to match the incoming devices against | |
214a6c79 | 782 | * @devtype: the devtype value to match the incoming devices against |
ce1d6d7f | 783 | * |
50579295 | 784 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
785 | * will usually not be woken up for devices which do not match. |
786 | * | |
ce1d6d7f KS |
787 | * The filter must be installed before the monitor is switched to listening mode. |
788 | * | |
789 | * Returns: 0 on success, otherwise a negative error value. | |
790 | */ | |
54cf0b7f | 791 | _public_ int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype) |
e14bdd88 | 792 | { |
912541b0 KS |
793 | if (udev_monitor == NULL) |
794 | return -EINVAL; | |
795 | if (subsystem == NULL) | |
796 | return -EINVAL; | |
797 | if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL) | |
798 | return -ENOMEM; | |
799 | return 0; | |
e14bdd88 | 800 | } |
08a7a795 | 801 | |
28460195 KS |
802 | /** |
803 | * udev_monitor_filter_add_match_tag: | |
804 | * @udev_monitor: the monitor | |
805 | * @tag: the name of a tag | |
806 | * | |
50579295 | 807 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
808 | * will usually not be woken up for devices which do not match. |
809 | * | |
810 | * The filter must be installed before the monitor is switched to listening mode. | |
811 | * | |
812 | * Returns: 0 on success, otherwise a negative error value. | |
813 | */ | |
54cf0b7f | 814 | _public_ int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag) |
28460195 | 815 | { |
912541b0 KS |
816 | if (udev_monitor == NULL) |
817 | return -EINVAL; | |
818 | if (tag == NULL) | |
819 | return -EINVAL; | |
820 | if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL) | |
821 | return -ENOMEM; | |
822 | return 0; | |
28460195 KS |
823 | } |
824 | ||
ce1d6d7f KS |
825 | /** |
826 | * udev_monitor_filter_remove: | |
827 | * @udev_monitor: monitor | |
828 | * | |
829 | * Remove all filters from monitor. | |
830 | * | |
831 | * Returns: 0 on success, otherwise a negative error value. | |
832 | */ | |
54cf0b7f | 833 | _public_ int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
08a7a795 | 834 | { |
912541b0 | 835 | static struct sock_fprog filter = { 0, NULL }; |
08a7a795 | 836 | |
912541b0 KS |
837 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
838 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
08a7a795 | 839 | } |