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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 | |
07630cea LP |
20 | #include <errno.h> |
21 | #include <linux/filter.h> | |
22 | #include <linux/netlink.h> | |
23 | #include <poll.h> | |
24 | #include <stddef.h> | |
ba6929f6 KS |
25 | #include <stdio.h> |
26 | #include <stdlib.h> | |
ba6929f6 | 27 | #include <string.h> |
ba6929f6 | 28 | #include <sys/socket.h> |
07630cea | 29 | #include <unistd.h> |
ba6929f6 KS |
30 | |
31 | #include "libudev.h" | |
07630cea | 32 | |
3ffd4af2 | 33 | #include "fd-util.h" |
0d39fa9c | 34 | #include "fileio.h" |
07630cea | 35 | #include "formats-util.h" |
ba6929f6 | 36 | #include "libudev-private.h" |
df32a1ca | 37 | #include "missing.h" |
07630cea LP |
38 | #include "socket-util.h" |
39 | #include "string-util.h" | |
ba6929f6 | 40 | |
ce1d6d7f KS |
41 | /** |
42 | * SECTION:libudev-monitor | |
43 | * @short_description: device event source | |
44 | * | |
45 | * Connects to a device event source. | |
46 | */ | |
47 | ||
ce1d6d7f KS |
48 | /** |
49 | * udev_monitor: | |
50 | * | |
50579295 | 51 | * Opaque object handling an event source. |
ce1d6d7f | 52 | */ |
ba6929f6 | 53 | struct udev_monitor { |
912541b0 KS |
54 | struct udev *udev; |
55 | int refcount; | |
56 | int sock; | |
b49d9b50 KS |
57 | union sockaddr_union snl; |
58 | union sockaddr_union snl_trusted_sender; | |
59 | union sockaddr_union snl_destination; | |
912541b0 KS |
60 | socklen_t addrlen; |
61 | struct udev_list filter_subsystem_list; | |
62 | struct udev_list filter_tag_list; | |
63 | bool bound; | |
ba6929f6 KS |
64 | }; |
65 | ||
f2b93744 | 66 | enum udev_monitor_netlink_group { |
912541b0 KS |
67 | UDEV_MONITOR_NONE, |
68 | UDEV_MONITOR_KERNEL, | |
69 | UDEV_MONITOR_UDEV, | |
f2b93744 KS |
70 | }; |
71 | ||
912541b0 | 72 | #define UDEV_MONITOR_MAGIC 0xfeedcafe |
e14bdd88 | 73 | struct udev_monitor_netlink_header { |
912541b0 KS |
74 | /* "libudev" prefix to distinguish libudev and kernel messages */ |
75 | char prefix[8]; | |
76 | /* | |
77 | * magic to protect against daemon <-> library message format mismatch | |
78 | * used in the kernel from socket filter rules; needs to be stored in network order | |
79 | */ | |
80 | unsigned int magic; | |
81 | /* total length of header structure known to the sender */ | |
82 | unsigned int header_size; | |
83 | /* properties string buffer */ | |
84 | unsigned int properties_off; | |
85 | unsigned int properties_len; | |
86 | /* | |
87 | * hashes of primary device properties strings, to let libudev subscribers | |
88 | * use in-kernel socket filters; values need to be stored in network order | |
89 | */ | |
90 | unsigned int filter_subsystem_hash; | |
91 | unsigned int filter_devtype_hash; | |
92 | unsigned int filter_tag_bloom_hi; | |
93 | unsigned int filter_tag_bloom_lo; | |
e14bdd88 KS |
94 | }; |
95 | ||
96 | static struct udev_monitor *udev_monitor_new(struct udev *udev) | |
97 | { | |
912541b0 KS |
98 | struct udev_monitor *udev_monitor; |
99 | ||
955d98c9 | 100 | udev_monitor = new0(struct udev_monitor, 1); |
912541b0 KS |
101 | if (udev_monitor == NULL) |
102 | return NULL; | |
103 | udev_monitor->refcount = 1; | |
104 | udev_monitor->udev = udev; | |
105 | udev_list_init(udev, &udev_monitor->filter_subsystem_list, false); | |
106 | udev_list_init(udev, &udev_monitor->filter_tag_list, true); | |
107 | return udev_monitor; | |
e14bdd88 KS |
108 | } |
109 | ||
df32a1ca KS |
110 | /* we consider udev running when /dev is on devtmpfs */ |
111 | static bool udev_has_devtmpfs(struct udev *udev) { | |
21749924 | 112 | |
2695c5c4 | 113 | union file_handle_union h = FILE_HANDLE_INIT; |
df32a1ca KS |
114 | _cleanup_fclose_ FILE *f = NULL; |
115 | char line[LINE_MAX], *e; | |
21749924 | 116 | int mount_id; |
df32a1ca KS |
117 | int r; |
118 | ||
370c860f | 119 | r = name_to_handle_at(AT_FDCWD, "/dev", &h.handle, &mount_id, 0); |
e6c47472 ZJS |
120 | if (r < 0) { |
121 | if (errno != EOPNOTSUPP) | |
56f64d95 | 122 | log_debug_errno(errno, "name_to_handle_at on /dev: %m"); |
df32a1ca | 123 | return false; |
e6c47472 | 124 | } |
df32a1ca | 125 | |
df32a1ca KS |
126 | f = fopen("/proc/self/mountinfo", "re"); |
127 | if (!f) | |
128 | return false; | |
129 | ||
130 | FOREACH_LINE(line, f, return false) { | |
df32a1ca KS |
131 | int mid; |
132 | ||
133 | if (sscanf(line, "%i", &mid) != 1) | |
134 | continue; | |
135 | ||
136 | if (mid != mount_id) | |
137 | continue; | |
138 | ||
139 | e = strstr(line, " - "); | |
140 | if (!e) | |
141 | continue; | |
142 | ||
143 | /* accept any name that starts with the currently expected type */ | |
144 | if (startswith(e + 3, "devtmpfs")) | |
145 | return true; | |
146 | } | |
147 | ||
148 | return false; | |
149 | } | |
150 | ||
44daf75d TG |
151 | static void monitor_set_nl_address(struct udev_monitor *udev_monitor) { |
152 | union sockaddr_union snl; | |
153 | socklen_t addrlen; | |
154 | int r; | |
155 | ||
156 | assert(udev_monitor); | |
157 | ||
158 | /* get the address the kernel has assigned us | |
159 | * it is usually, but not necessarily the pid | |
160 | */ | |
161 | addrlen = sizeof(struct sockaddr_nl); | |
162 | r = getsockname(udev_monitor->sock, &snl.sa, &addrlen); | |
163 | if (r >= 0) | |
164 | udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid; | |
165 | } | |
166 | ||
7459bcdc | 167 | struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) |
1c7047ea | 168 | { |
912541b0 KS |
169 | struct udev_monitor *udev_monitor; |
170 | unsigned int group; | |
171 | ||
172 | if (udev == NULL) | |
173 | return NULL; | |
174 | ||
175 | if (name == NULL) | |
176 | group = UDEV_MONITOR_NONE; | |
e8a3b2dc KS |
177 | else if (streq(name, "udev")) { |
178 | /* | |
179 | * We do not support subscribing to uevents if no instance of | |
180 | * udev is running. Uevents would otherwise broadcast the | |
181 | * processing data of the host into containers, which is not | |
182 | * desired. | |
183 | * | |
184 | * Containers will currently not get any udev uevents, until | |
185 | * a supporting infrastructure is available. | |
186 | * | |
187 | * We do not set a netlink multicast group here, so the socket | |
188 | * will not receive any messages. | |
189 | */ | |
9ea28c55 | 190 | if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) { |
ff49bc32 | 191 | log_debug("the udev service seems not to be active, disable the monitor"); |
e8a3b2dc KS |
192 | group = UDEV_MONITOR_NONE; |
193 | } else | |
194 | group = UDEV_MONITOR_UDEV; | |
195 | } else if (streq(name, "kernel")) | |
912541b0 KS |
196 | group = UDEV_MONITOR_KERNEL; |
197 | else | |
198 | return NULL; | |
199 | ||
200 | udev_monitor = udev_monitor_new(udev); | |
201 | if (udev_monitor == NULL) | |
202 | return NULL; | |
203 | ||
204 | if (fd < 0) { | |
205 | udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); | |
44daf75d | 206 | if (udev_monitor->sock < 0) { |
56f64d95 | 207 | log_debug_errno(errno, "error getting socket: %m"); |
912541b0 KS |
208 | free(udev_monitor); |
209 | return NULL; | |
210 | } | |
211 | } else { | |
212 | udev_monitor->bound = true; | |
213 | udev_monitor->sock = fd; | |
44daf75d | 214 | monitor_set_nl_address(udev_monitor); |
912541b0 KS |
215 | } |
216 | ||
b49d9b50 KS |
217 | udev_monitor->snl.nl.nl_family = AF_NETLINK; |
218 | udev_monitor->snl.nl.nl_groups = group; | |
912541b0 KS |
219 | |
220 | /* default destination for sending */ | |
b49d9b50 KS |
221 | udev_monitor->snl_destination.nl.nl_family = AF_NETLINK; |
222 | udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV; | |
912541b0 | 223 | |
912541b0 | 224 | return udev_monitor; |
1c7047ea KS |
225 | } |
226 | ||
7459bcdc KS |
227 | /** |
228 | * udev_monitor_new_from_netlink: | |
229 | * @udev: udev library context | |
230 | * @name: name of event source | |
231 | * | |
232 | * Create new udev monitor and connect to a specified event | |
233 | * source. Valid sources identifiers are "udev" and "kernel". | |
234 | * | |
235 | * Applications should usually not connect directly to the | |
236 | * "kernel" events, because the devices might not be useable | |
237 | * at that time, before udev has configured them, and created | |
50579295 KS |
238 | * device nodes. Accessing devices at the same time as udev, |
239 | * might result in unpredictable behavior. The "udev" events | |
240 | * are sent out after udev has finished its event processing, | |
241 | * all rules have been processed, and needed device nodes are | |
242 | * created. | |
7459bcdc KS |
243 | * |
244 | * The initial refcount is 1, and needs to be decremented to | |
245 | * release the resources of the udev monitor. | |
246 | * | |
247 | * Returns: a new udev monitor, or #NULL, in case of an error | |
248 | **/ | |
54cf0b7f | 249 | _public_ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) |
7459bcdc | 250 | { |
912541b0 | 251 | return udev_monitor_new_from_netlink_fd(udev, name, -1); |
7459bcdc KS |
252 | } |
253 | ||
e14bdd88 | 254 | static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i, |
912541b0 | 255 | unsigned short code, unsigned int data) |
e14bdd88 | 256 | { |
912541b0 | 257 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 258 | |
912541b0 KS |
259 | ins->code = code; |
260 | ins->k = data; | |
261 | (*i)++; | |
e14bdd88 KS |
262 | } |
263 | ||
264 | static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i, | |
912541b0 KS |
265 | unsigned short code, unsigned int data, |
266 | unsigned short jt, unsigned short jf) | |
e14bdd88 | 267 | { |
912541b0 | 268 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 269 | |
912541b0 KS |
270 | ins->code = code; |
271 | ins->jt = jt; | |
272 | ins->jf = jf; | |
273 | ins->k = data; | |
274 | (*i)++; | |
e14bdd88 KS |
275 | } |
276 | ||
ce1d6d7f KS |
277 | /** |
278 | * udev_monitor_filter_update: | |
279 | * @udev_monitor: monitor | |
280 | * | |
50579295 KS |
281 | * Update the installed socket filter. This is only needed, |
282 | * if the filter was removed or changed. | |
ce1d6d7f KS |
283 | * |
284 | * Returns: 0 on success, otherwise a negative error value. | |
285 | */ | |
54cf0b7f | 286 | _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor) |
e14bdd88 | 287 | { |
912541b0 KS |
288 | struct sock_filter ins[512]; |
289 | struct sock_fprog filter; | |
290 | unsigned int i; | |
291 | struct udev_list_entry *list_entry; | |
292 | int err; | |
293 | ||
294 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL && | |
295 | udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) | |
296 | return 0; | |
297 | ||
29804cc1 | 298 | memzero(ins, sizeof(ins)); |
912541b0 KS |
299 | i = 0; |
300 | ||
301 | /* load magic in A */ | |
302 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic)); | |
303 | /* jump if magic matches */ | |
304 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); | |
305 | /* wrong magic, pass packet */ | |
306 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
307 | ||
308 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) { | |
309 | int tag_matches; | |
310 | ||
311 | /* count tag matches, to calculate end of tag match block */ | |
312 | tag_matches = 0; | |
313 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) | |
314 | tag_matches++; | |
315 | ||
316 | /* add all tags matches */ | |
317 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
318 | uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
319 | uint32_t tag_bloom_hi = tag_bloom_bits >> 32; | |
320 | uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; | |
321 | ||
322 | /* load device bloom bits in A */ | |
323 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi)); | |
324 | /* clear bits (tag bits & bloom bits) */ | |
325 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); | |
326 | /* jump to next tag if it does not match */ | |
327 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); | |
328 | ||
329 | /* load device bloom bits in A */ | |
330 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo)); | |
331 | /* clear bits (tag bits & bloom bits) */ | |
332 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); | |
333 | /* jump behind end of tag match block if tag matches */ | |
334 | tag_matches--; | |
335 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); | |
336 | } | |
337 | ||
338 | /* nothing matched, drop packet */ | |
339 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
340 | } | |
341 | ||
342 | /* add all subsystem matches */ | |
343 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) { | |
344 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
345 | unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry)); | |
346 | ||
347 | /* load device subsystem value in A */ | |
348 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash)); | |
349 | if (udev_list_entry_get_value(list_entry) == NULL) { | |
350 | /* jump if subsystem does not match */ | |
351 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
352 | } else { | |
353 | /* jump if subsystem does not match */ | |
354 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); | |
355 | ||
356 | /* load device devtype value in A */ | |
357 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash)); | |
358 | /* jump if value does not match */ | |
359 | hash = util_string_hash32(udev_list_entry_get_value(list_entry)); | |
360 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
361 | } | |
362 | ||
363 | /* matched, pass packet */ | |
364 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
365 | ||
8fef0ff2 | 366 | if (i+1 >= ELEMENTSOF(ins)) |
994e0234 | 367 | return -E2BIG; |
912541b0 KS |
368 | } |
369 | ||
370 | /* nothing matched, drop packet */ | |
371 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
372 | } | |
373 | ||
374 | /* matched, pass packet */ | |
375 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
376 | ||
377 | /* install filter */ | |
29804cc1 | 378 | memzero(&filter, sizeof(filter)); |
912541b0 KS |
379 | filter.len = i; |
380 | filter.filter = ins; | |
381 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
994e0234 | 382 | return err < 0 ? -errno : 0; |
e14bdd88 KS |
383 | } |
384 | ||
1e03b754 KS |
385 | int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
386 | { | |
b49d9b50 | 387 | udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid; |
912541b0 | 388 | return 0; |
1e03b754 | 389 | } |
44daf75d | 390 | |
ce1d6d7f KS |
391 | /** |
392 | * udev_monitor_enable_receiving: | |
393 | * @udev_monitor: the monitor which should receive events | |
394 | * | |
395 | * Binds the @udev_monitor socket to the event source. | |
396 | * | |
397 | * Returns: 0 on success, otherwise a negative error value. | |
398 | */ | |
54cf0b7f | 399 | _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
d59f11e1 | 400 | { |
912541b0 KS |
401 | int err = 0; |
402 | const int on = 1; | |
403 | ||
2d13da88 KS |
404 | udev_monitor_filter_update(udev_monitor); |
405 | ||
406 | if (!udev_monitor->bound) { | |
407 | err = bind(udev_monitor->sock, | |
b49d9b50 | 408 | &udev_monitor->snl.sa, sizeof(struct sockaddr_nl)); |
2d13da88 KS |
409 | if (err == 0) |
410 | udev_monitor->bound = true; | |
912541b0 KS |
411 | } |
412 | ||
44daf75d TG |
413 | if (err >= 0) |
414 | monitor_set_nl_address(udev_monitor); | |
415 | else { | |
56f64d95 | 416 | log_debug_errno(errno, "bind failed: %m"); |
994e0234 | 417 | return -errno; |
912541b0 KS |
418 | } |
419 | ||
420 | /* enable receiving of sender credentials */ | |
9dedfe7f TG |
421 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); |
422 | if (err < 0) | |
56f64d95 | 423 | log_debug_errno(errno, "setting SO_PASSCRED failed: %m"); |
9dedfe7f | 424 | |
912541b0 | 425 | return 0; |
ba6929f6 KS |
426 | } |
427 | ||
f712894d KS |
428 | /** |
429 | * udev_monitor_set_receive_buffer_size: | |
430 | * @udev_monitor: the monitor which should receive events | |
431 | * @size: the size in bytes | |
432 | * | |
433 | * Set the size of the kernel socket buffer. This call needs the | |
434 | * appropriate privileges to succeed. | |
435 | * | |
436 | * Returns: 0 on success, otherwise -1 on error. | |
437 | */ | |
54cf0b7f | 438 | _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
cb25a958 | 439 | { |
912541b0 | 440 | if (udev_monitor == NULL) |
994e0234 | 441 | return -EINVAL; |
912541b0 | 442 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)); |
cb25a958 KS |
443 | } |
444 | ||
1e03b754 KS |
445 | int udev_monitor_disconnect(struct udev_monitor *udev_monitor) |
446 | { | |
912541b0 | 447 | int err; |
1e03b754 | 448 | |
912541b0 KS |
449 | err = close(udev_monitor->sock); |
450 | udev_monitor->sock = -1; | |
994e0234 | 451 | return err < 0 ? -errno : 0; |
1e03b754 KS |
452 | } |
453 | ||
7d8787b3 KS |
454 | /** |
455 | * udev_monitor_ref: | |
456 | * @udev_monitor: udev monitor | |
457 | * | |
458 | * Take a reference of a udev monitor. | |
459 | * | |
460 | * Returns: the passed udev monitor | |
461 | **/ | |
54cf0b7f | 462 | _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor) |
ba6929f6 | 463 | { |
912541b0 KS |
464 | if (udev_monitor == NULL) |
465 | return NULL; | |
466 | udev_monitor->refcount++; | |
467 | return udev_monitor; | |
ba6929f6 KS |
468 | } |
469 | ||
7d8787b3 KS |
470 | /** |
471 | * udev_monitor_unref: | |
472 | * @udev_monitor: udev monitor | |
473 | * | |
ff109b8d | 474 | * Drop a reference of a udev monitor. If the refcount reaches zero, |
be7de409 | 475 | * the bound socket will be closed, and the resources of the monitor |
7d8787b3 KS |
476 | * will be released. |
477 | * | |
725d7e6c | 478 | * Returns: #NULL |
7d8787b3 | 479 | **/ |
20bbd54f | 480 | _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor) |
ba6929f6 | 481 | { |
912541b0 | 482 | if (udev_monitor == NULL) |
20bbd54f | 483 | return NULL; |
912541b0 KS |
484 | udev_monitor->refcount--; |
485 | if (udev_monitor->refcount > 0) | |
725d7e6c | 486 | return NULL; |
912541b0 KS |
487 | if (udev_monitor->sock >= 0) |
488 | close(udev_monitor->sock); | |
489 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); | |
490 | udev_list_cleanup(&udev_monitor->filter_tag_list); | |
912541b0 | 491 | free(udev_monitor); |
20bbd54f | 492 | return NULL; |
ba6929f6 KS |
493 | } |
494 | ||
7d8787b3 KS |
495 | /** |
496 | * udev_monitor_get_udev: | |
497 | * @udev_monitor: udev monitor | |
498 | * | |
b98fd840 | 499 | * Retrieve the udev library context the monitor was created with. |
7d8787b3 KS |
500 | * |
501 | * Returns: the udev library context | |
502 | **/ | |
54cf0b7f | 503 | _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor) |
ba6929f6 | 504 | { |
912541b0 KS |
505 | if (udev_monitor == NULL) |
506 | return NULL; | |
507 | return udev_monitor->udev; | |
ba6929f6 KS |
508 | } |
509 | ||
7d8787b3 KS |
510 | /** |
511 | * udev_monitor_get_fd: | |
512 | * @udev_monitor: udev monitor | |
513 | * | |
514 | * Retrieve the socket file descriptor associated with the monitor. | |
515 | * | |
516 | * Returns: the socket file descriptor | |
517 | **/ | |
54cf0b7f | 518 | _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
ba6929f6 | 519 | { |
912541b0 | 520 | if (udev_monitor == NULL) |
994e0234 | 521 | return -EINVAL; |
912541b0 | 522 | return udev_monitor->sock; |
ba6929f6 KS |
523 | } |
524 | ||
e14bdd88 KS |
525 | static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device) |
526 | { | |
912541b0 KS |
527 | struct udev_list_entry *list_entry; |
528 | ||
529 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL) | |
530 | goto tag; | |
531 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
532 | const char *subsys = udev_list_entry_get_name(list_entry); | |
533 | const char *dsubsys = udev_device_get_subsystem(udev_device); | |
534 | const char *devtype; | |
535 | const char *ddevtype; | |
536 | ||
090be865 | 537 | if (!streq(dsubsys, subsys)) |
912541b0 KS |
538 | continue; |
539 | ||
540 | devtype = udev_list_entry_get_value(list_entry); | |
541 | if (devtype == NULL) | |
542 | goto tag; | |
543 | ddevtype = udev_device_get_devtype(udev_device); | |
544 | if (ddevtype == NULL) | |
545 | continue; | |
090be865 | 546 | if (streq(ddevtype, devtype)) |
912541b0 KS |
547 | goto tag; |
548 | } | |
549 | return 0; | |
28460195 KS |
550 | |
551 | tag: | |
912541b0 KS |
552 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) |
553 | return 1; | |
554 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
555 | const char *tag = udev_list_entry_get_name(list_entry); | |
556 | ||
557 | if (udev_device_has_tag(udev_device, tag)) | |
558 | return 1; | |
559 | } | |
560 | return 0; | |
e14bdd88 KS |
561 | } |
562 | ||
7d8787b3 | 563 | /** |
d59f11e1 | 564 | * udev_monitor_receive_device: |
7d8787b3 KS |
565 | * @udev_monitor: udev monitor |
566 | * | |
d59f11e1 | 567 | * Receive data from the udev monitor socket, allocate a new udev |
b98fd840 | 568 | * device, fill in the received data, and return the device. |
7d8787b3 | 569 | * |
50579295 | 570 | * Only socket connections with uid=0 are accepted. |
7d8787b3 | 571 | * |
b30b4260 KS |
572 | * The monitor socket is by default set to NONBLOCK. A variant of poll() on |
573 | * the file descriptor returned by udev_monitor_get_fd() should to be used to | |
574 | * wake up when new devices arrive, or alternatively the file descriptor | |
575 | * switched into blocking mode. | |
576 | * | |
7d8787b3 | 577 | * The initial refcount is 1, and needs to be decremented to |
be7de409 | 578 | * release the resources of the udev device. |
7d8787b3 KS |
579 | * |
580 | * Returns: a new udev device, or #NULL, in case of an error | |
581 | **/ | |
54cf0b7f | 582 | _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor) |
ba6929f6 | 583 | { |
912541b0 KS |
584 | struct udev_device *udev_device; |
585 | struct msghdr smsg; | |
586 | struct iovec iov; | |
587 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
588 | struct cmsghdr *cmsg; | |
b49d9b50 | 589 | union sockaddr_union snl; |
912541b0 | 590 | struct ucred *cred; |
bf3dd6b1 SL |
591 | union { |
592 | struct udev_monitor_netlink_header nlh; | |
593 | char raw[8192]; | |
594 | } buf; | |
912541b0 KS |
595 | ssize_t buflen; |
596 | ssize_t bufpos; | |
2df959ec | 597 | bool is_initialized = false; |
ba6929f6 | 598 | |
e14bdd88 | 599 | retry: |
912541b0 KS |
600 | if (udev_monitor == NULL) |
601 | return NULL; | |
912541b0 KS |
602 | iov.iov_base = &buf; |
603 | iov.iov_len = sizeof(buf); | |
29804cc1 | 604 | memzero(&smsg, sizeof(struct msghdr)); |
912541b0 KS |
605 | smsg.msg_iov = &iov; |
606 | smsg.msg_iovlen = 1; | |
607 | smsg.msg_control = cred_msg; | |
608 | smsg.msg_controllen = sizeof(cred_msg); | |
f6613dd9 KS |
609 | smsg.msg_name = &snl; |
610 | smsg.msg_namelen = sizeof(snl); | |
912541b0 | 611 | |
a38d9945 | 612 | buflen = recvmsg(udev_monitor->sock, &smsg, 0); |
912541b0 KS |
613 | if (buflen < 0) { |
614 | if (errno != EINTR) | |
ff49bc32 | 615 | log_debug("unable to receive message"); |
912541b0 KS |
616 | return NULL; |
617 | } | |
618 | ||
9c89c1ca | 619 | if (buflen < 32 || (smsg.msg_flags & MSG_TRUNC)) { |
ff49bc32 | 620 | log_debug("invalid message length"); |
912541b0 KS |
621 | return NULL; |
622 | } | |
623 | ||
f6613dd9 KS |
624 | if (snl.nl.nl_groups == 0) { |
625 | /* unicast message, check if we trust the sender */ | |
626 | if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 || | |
627 | snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) { | |
ff49bc32 | 628 | log_debug("unicast netlink message ignored"); |
f6613dd9 KS |
629 | return NULL; |
630 | } | |
631 | } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) { | |
632 | if (snl.nl.nl_pid > 0) { | |
1fa2f38f ZJS |
633 | log_debug("multicast kernel netlink message from PID %"PRIu32" ignored", |
634 | snl.nl.nl_pid); | |
f6613dd9 | 635 | return NULL; |
912541b0 KS |
636 | } |
637 | } | |
638 | ||
639 | cmsg = CMSG_FIRSTHDR(&smsg); | |
640 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
ff49bc32 | 641 | log_debug("no sender credentials received, message ignored"); |
912541b0 KS |
642 | return NULL; |
643 | } | |
644 | ||
645 | cred = (struct ucred *)CMSG_DATA(cmsg); | |
646 | if (cred->uid != 0) { | |
1fa2f38f | 647 | log_debug("sender uid="UID_FMT", message ignored", cred->uid); |
912541b0 KS |
648 | return NULL; |
649 | } | |
650 | ||
bf3dd6b1 | 651 | if (memcmp(buf.raw, "libudev", 8) == 0) { |
912541b0 | 652 | /* udev message needs proper version magic */ |
bf3dd6b1 | 653 | if (buf.nlh.magic != htonl(UDEV_MONITOR_MAGIC)) { |
ff49bc32 | 654 | log_debug("unrecognized message signature (%x != %x)", |
bf3dd6b1 | 655 | buf.nlh.magic, htonl(UDEV_MONITOR_MAGIC)); |
912541b0 KS |
656 | return NULL; |
657 | } | |
bf3dd6b1 | 658 | if (buf.nlh.properties_off+32 > (size_t)buflen) { |
e6ac88dd TG |
659 | log_debug("message smaller than expected (%u > %zd)", |
660 | buf.nlh.properties_off+32, buflen); | |
912541b0 | 661 | return NULL; |
f6613dd9 KS |
662 | } |
663 | ||
bf3dd6b1 | 664 | bufpos = buf.nlh.properties_off; |
f6613dd9 KS |
665 | |
666 | /* devices received from udev are always initialized */ | |
2df959ec | 667 | is_initialized = true; |
912541b0 KS |
668 | } else { |
669 | /* kernel message with header */ | |
bf3dd6b1 | 670 | bufpos = strlen(buf.raw) + 1; |
912541b0 | 671 | if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { |
ff49bc32 | 672 | log_debug("invalid message length"); |
912541b0 KS |
673 | return NULL; |
674 | } | |
675 | ||
676 | /* check message header */ | |
bf3dd6b1 | 677 | if (strstr(buf.raw, "@/") == NULL) { |
ff49bc32 | 678 | log_debug("unrecognized message header"); |
912541b0 KS |
679 | return NULL; |
680 | } | |
681 | } | |
682 | ||
2df959ec | 683 | udev_device = udev_device_new_from_nulstr(udev_monitor->udev, &buf.raw[bufpos], buflen - bufpos); |
e6ac88dd TG |
684 | if (!udev_device) { |
685 | log_debug("could not create device: %m"); | |
912541b0 | 686 | return NULL; |
e6ac88dd | 687 | } |
2df959ec TG |
688 | |
689 | if (is_initialized) | |
690 | udev_device_set_is_initialized(udev_device); | |
912541b0 KS |
691 | |
692 | /* skip device, if it does not pass the current filter */ | |
693 | if (!passes_filter(udev_monitor, udev_device)) { | |
694 | struct pollfd pfd[1]; | |
695 | int rc; | |
696 | ||
697 | udev_device_unref(udev_device); | |
698 | ||
699 | /* if something is queued, get next device */ | |
700 | pfd[0].fd = udev_monitor->sock; | |
701 | pfd[0].events = POLLIN; | |
702 | rc = poll(pfd, 1, 0); | |
703 | if (rc > 0) | |
704 | goto retry; | |
705 | return NULL; | |
706 | } | |
707 | ||
708 | return udev_device; | |
ba6929f6 | 709 | } |
9925ab04 | 710 | |
1e03b754 | 711 | int udev_monitor_send_device(struct udev_monitor *udev_monitor, |
912541b0 | 712 | struct udev_monitor *destination, struct udev_device *udev_device) |
9925ab04 | 713 | { |
81b9fe54 ZJS |
714 | const char *buf, *val; |
715 | ssize_t blen, count; | |
716 | struct udev_monitor_netlink_header nlh = { | |
717 | .prefix = "libudev", | |
718 | .magic = htonl(UDEV_MONITOR_MAGIC), | |
719 | .header_size = sizeof nlh, | |
720 | }; | |
721 | struct iovec iov[2] = { | |
722 | { .iov_base = &nlh, .iov_len = sizeof nlh }, | |
723 | }; | |
724 | struct msghdr smsg = { | |
725 | .msg_iov = iov, | |
726 | .msg_iovlen = 2, | |
727 | }; | |
2d13da88 KS |
728 | struct udev_list_entry *list_entry; |
729 | uint64_t tag_bloom_bits; | |
730 | ||
912541b0 | 731 | blen = udev_device_get_properties_monitor_buf(udev_device, &buf); |
e6ac88dd TG |
732 | if (blen < 32) { |
733 | log_debug("device buffer is too small to contain a valid device"); | |
912541b0 | 734 | return -EINVAL; |
e6ac88dd | 735 | } |
912541b0 | 736 | |
81b9fe54 | 737 | /* fill in versioned header */ |
2d13da88 KS |
738 | val = udev_device_get_subsystem(udev_device); |
739 | nlh.filter_subsystem_hash = htonl(util_string_hash32(val)); | |
81b9fe54 | 740 | |
2d13da88 KS |
741 | val = udev_device_get_devtype(udev_device); |
742 | if (val != NULL) | |
743 | nlh.filter_devtype_hash = htonl(util_string_hash32(val)); | |
2d13da88 KS |
744 | |
745 | /* add tag bloom filter */ | |
746 | tag_bloom_bits = 0; | |
747 | udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device)) | |
748 | tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
749 | if (tag_bloom_bits > 0) { | |
750 | nlh.filter_tag_bloom_hi = htonl(tag_bloom_bits >> 32); | |
751 | nlh.filter_tag_bloom_lo = htonl(tag_bloom_bits & 0xffffffff); | |
912541b0 KS |
752 | } |
753 | ||
2d13da88 KS |
754 | /* add properties list */ |
755 | nlh.properties_off = iov[0].iov_len; | |
756 | nlh.properties_len = blen; | |
757 | iov[1].iov_base = (char *)buf; | |
758 | iov[1].iov_len = blen; | |
912541b0 | 759 | |
2d13da88 KS |
760 | /* |
761 | * Use custom address for target, or the default one. | |
762 | * | |
763 | * If we send to a multicast group, we will get | |
764 | * ECONNREFUSED, which is expected. | |
765 | */ | |
a4445e88 | 766 | if (destination) |
2d13da88 KS |
767 | smsg.msg_name = &destination->snl; |
768 | else | |
769 | smsg.msg_name = &udev_monitor->snl_destination; | |
770 | smsg.msg_namelen = sizeof(struct sockaddr_nl); | |
771 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
a4445e88 TG |
772 | if (count < 0) { |
773 | if (!destination && errno == ECONNREFUSED) { | |
7800bf71 | 774 | log_debug("passed device to netlink monitor %p", udev_monitor); |
a4445e88 TG |
775 | return 0; |
776 | } else | |
777 | return -errno; | |
778 | } | |
779 | ||
965288c5 | 780 | log_debug("passed %zi byte device to netlink monitor %p", count, udev_monitor); |
2d13da88 | 781 | return count; |
9925ab04 | 782 | } |
e14bdd88 | 783 | |
ce1d6d7f KS |
784 | /** |
785 | * udev_monitor_filter_add_match_subsystem_devtype: | |
786 | * @udev_monitor: the monitor | |
787 | * @subsystem: the subsystem value to match the incoming devices against | |
214a6c79 | 788 | * @devtype: the devtype value to match the incoming devices against |
ce1d6d7f | 789 | * |
50579295 | 790 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
791 | * will usually not be woken up for devices which do not match. |
792 | * | |
ce1d6d7f KS |
793 | * The filter must be installed before the monitor is switched to listening mode. |
794 | * | |
795 | * Returns: 0 on success, otherwise a negative error value. | |
796 | */ | |
54cf0b7f | 797 | _public_ int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype) |
e14bdd88 | 798 | { |
912541b0 KS |
799 | if (udev_monitor == NULL) |
800 | return -EINVAL; | |
801 | if (subsystem == NULL) | |
802 | return -EINVAL; | |
803 | if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL) | |
804 | return -ENOMEM; | |
805 | return 0; | |
e14bdd88 | 806 | } |
08a7a795 | 807 | |
28460195 KS |
808 | /** |
809 | * udev_monitor_filter_add_match_tag: | |
810 | * @udev_monitor: the monitor | |
811 | * @tag: the name of a tag | |
812 | * | |
50579295 | 813 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
814 | * will usually not be woken up for devices which do not match. |
815 | * | |
816 | * The filter must be installed before the monitor is switched to listening mode. | |
817 | * | |
818 | * Returns: 0 on success, otherwise a negative error value. | |
819 | */ | |
54cf0b7f | 820 | _public_ int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag) |
28460195 | 821 | { |
912541b0 KS |
822 | if (udev_monitor == NULL) |
823 | return -EINVAL; | |
824 | if (tag == NULL) | |
825 | return -EINVAL; | |
826 | if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL) | |
827 | return -ENOMEM; | |
828 | return 0; | |
28460195 KS |
829 | } |
830 | ||
ce1d6d7f KS |
831 | /** |
832 | * udev_monitor_filter_remove: | |
833 | * @udev_monitor: monitor | |
834 | * | |
835 | * Remove all filters from monitor. | |
836 | * | |
837 | * Returns: 0 on success, otherwise a negative error value. | |
838 | */ | |
54cf0b7f | 839 | _public_ int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
08a7a795 | 840 | { |
912541b0 | 841 | static struct sock_fprog filter = { 0, NULL }; |
08a7a795 | 842 | |
912541b0 KS |
843 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
844 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
08a7a795 | 845 | } |