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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> | |
0a6f50c0 | 26 | #include <poll.h> |
ba6929f6 | 27 | #include <sys/socket.h> |
1c7047ea | 28 | #include <linux/netlink.h> |
e14bdd88 | 29 | #include <linux/filter.h> |
ba6929f6 KS |
30 | |
31 | #include "libudev.h" | |
32 | #include "libudev-private.h" | |
b49d9b50 | 33 | #include "socket-util.h" |
df32a1ca | 34 | #include "missing.h" |
6482f626 | 35 | #include "formats-util.h" |
ba6929f6 | 36 | |
ce1d6d7f KS |
37 | /** |
38 | * SECTION:libudev-monitor | |
39 | * @short_description: device event source | |
40 | * | |
41 | * Connects to a device event source. | |
42 | */ | |
43 | ||
ce1d6d7f KS |
44 | /** |
45 | * udev_monitor: | |
46 | * | |
50579295 | 47 | * Opaque object handling an event source. |
ce1d6d7f | 48 | */ |
ba6929f6 | 49 | struct udev_monitor { |
912541b0 KS |
50 | struct udev *udev; |
51 | int refcount; | |
52 | int sock; | |
b49d9b50 KS |
53 | union sockaddr_union snl; |
54 | union sockaddr_union snl_trusted_sender; | |
55 | union sockaddr_union snl_destination; | |
912541b0 KS |
56 | socklen_t addrlen; |
57 | struct udev_list filter_subsystem_list; | |
58 | struct udev_list filter_tag_list; | |
59 | bool bound; | |
ba6929f6 KS |
60 | }; |
61 | ||
f2b93744 | 62 | enum udev_monitor_netlink_group { |
912541b0 KS |
63 | UDEV_MONITOR_NONE, |
64 | UDEV_MONITOR_KERNEL, | |
65 | UDEV_MONITOR_UDEV, | |
f2b93744 KS |
66 | }; |
67 | ||
912541b0 | 68 | #define UDEV_MONITOR_MAGIC 0xfeedcafe |
e14bdd88 | 69 | struct udev_monitor_netlink_header { |
912541b0 KS |
70 | /* "libudev" prefix to distinguish libudev and kernel messages */ |
71 | char prefix[8]; | |
72 | /* | |
73 | * magic to protect against daemon <-> library message format mismatch | |
74 | * used in the kernel from socket filter rules; needs to be stored in network order | |
75 | */ | |
76 | unsigned int magic; | |
77 | /* total length of header structure known to the sender */ | |
78 | unsigned int header_size; | |
79 | /* properties string buffer */ | |
80 | unsigned int properties_off; | |
81 | unsigned int properties_len; | |
82 | /* | |
83 | * hashes of primary device properties strings, to let libudev subscribers | |
84 | * use in-kernel socket filters; values need to be stored in network order | |
85 | */ | |
86 | unsigned int filter_subsystem_hash; | |
87 | unsigned int filter_devtype_hash; | |
88 | unsigned int filter_tag_bloom_hi; | |
89 | unsigned int filter_tag_bloom_lo; | |
e14bdd88 KS |
90 | }; |
91 | ||
92 | static struct udev_monitor *udev_monitor_new(struct udev *udev) | |
93 | { | |
912541b0 KS |
94 | struct udev_monitor *udev_monitor; |
95 | ||
955d98c9 | 96 | udev_monitor = new0(struct udev_monitor, 1); |
912541b0 KS |
97 | if (udev_monitor == NULL) |
98 | return NULL; | |
99 | udev_monitor->refcount = 1; | |
100 | udev_monitor->udev = udev; | |
101 | udev_list_init(udev, &udev_monitor->filter_subsystem_list, false); | |
102 | udev_list_init(udev, &udev_monitor->filter_tag_list, true); | |
103 | return udev_monitor; | |
e14bdd88 KS |
104 | } |
105 | ||
df32a1ca KS |
106 | /* we consider udev running when /dev is on devtmpfs */ |
107 | static bool udev_has_devtmpfs(struct udev *udev) { | |
21749924 | 108 | |
2695c5c4 | 109 | union file_handle_union h = FILE_HANDLE_INIT; |
df32a1ca KS |
110 | _cleanup_fclose_ FILE *f = NULL; |
111 | char line[LINE_MAX], *e; | |
21749924 | 112 | int mount_id; |
df32a1ca KS |
113 | int r; |
114 | ||
370c860f | 115 | r = name_to_handle_at(AT_FDCWD, "/dev", &h.handle, &mount_id, 0); |
e6c47472 ZJS |
116 | if (r < 0) { |
117 | if (errno != EOPNOTSUPP) | |
56f64d95 | 118 | log_debug_errno(errno, "name_to_handle_at on /dev: %m"); |
df32a1ca | 119 | return false; |
e6c47472 | 120 | } |
df32a1ca | 121 | |
df32a1ca KS |
122 | f = fopen("/proc/self/mountinfo", "re"); |
123 | if (!f) | |
124 | return false; | |
125 | ||
126 | FOREACH_LINE(line, f, return false) { | |
df32a1ca KS |
127 | int mid; |
128 | ||
129 | if (sscanf(line, "%i", &mid) != 1) | |
130 | continue; | |
131 | ||
132 | if (mid != mount_id) | |
133 | continue; | |
134 | ||
135 | e = strstr(line, " - "); | |
136 | if (!e) | |
137 | continue; | |
138 | ||
139 | /* accept any name that starts with the currently expected type */ | |
140 | if (startswith(e + 3, "devtmpfs")) | |
141 | return true; | |
142 | } | |
143 | ||
144 | return false; | |
145 | } | |
146 | ||
44daf75d TG |
147 | static void monitor_set_nl_address(struct udev_monitor *udev_monitor) { |
148 | union sockaddr_union snl; | |
149 | socklen_t addrlen; | |
150 | int r; | |
151 | ||
152 | assert(udev_monitor); | |
153 | ||
154 | /* get the address the kernel has assigned us | |
155 | * it is usually, but not necessarily the pid | |
156 | */ | |
157 | addrlen = sizeof(struct sockaddr_nl); | |
158 | r = getsockname(udev_monitor->sock, &snl.sa, &addrlen); | |
159 | if (r >= 0) | |
160 | udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid; | |
161 | } | |
162 | ||
7459bcdc | 163 | struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) |
1c7047ea | 164 | { |
912541b0 KS |
165 | struct udev_monitor *udev_monitor; |
166 | unsigned int group; | |
167 | ||
168 | if (udev == NULL) | |
169 | return NULL; | |
170 | ||
171 | if (name == NULL) | |
172 | group = UDEV_MONITOR_NONE; | |
e8a3b2dc KS |
173 | else if (streq(name, "udev")) { |
174 | /* | |
175 | * We do not support subscribing to uevents if no instance of | |
176 | * udev is running. Uevents would otherwise broadcast the | |
177 | * processing data of the host into containers, which is not | |
178 | * desired. | |
179 | * | |
180 | * Containers will currently not get any udev uevents, until | |
181 | * a supporting infrastructure is available. | |
182 | * | |
183 | * We do not set a netlink multicast group here, so the socket | |
184 | * will not receive any messages. | |
185 | */ | |
9ea28c55 | 186 | if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) { |
ff49bc32 | 187 | log_debug("the udev service seems not to be active, disable the monitor"); |
e8a3b2dc KS |
188 | group = UDEV_MONITOR_NONE; |
189 | } else | |
190 | group = UDEV_MONITOR_UDEV; | |
191 | } else if (streq(name, "kernel")) | |
912541b0 KS |
192 | group = UDEV_MONITOR_KERNEL; |
193 | else | |
194 | return NULL; | |
195 | ||
196 | udev_monitor = udev_monitor_new(udev); | |
197 | if (udev_monitor == NULL) | |
198 | return NULL; | |
199 | ||
200 | if (fd < 0) { | |
201 | udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); | |
44daf75d | 202 | if (udev_monitor->sock < 0) { |
56f64d95 | 203 | log_debug_errno(errno, "error getting socket: %m"); |
912541b0 KS |
204 | free(udev_monitor); |
205 | return NULL; | |
206 | } | |
207 | } else { | |
208 | udev_monitor->bound = true; | |
209 | udev_monitor->sock = fd; | |
44daf75d | 210 | monitor_set_nl_address(udev_monitor); |
912541b0 KS |
211 | } |
212 | ||
b49d9b50 KS |
213 | udev_monitor->snl.nl.nl_family = AF_NETLINK; |
214 | udev_monitor->snl.nl.nl_groups = group; | |
912541b0 KS |
215 | |
216 | /* default destination for sending */ | |
b49d9b50 KS |
217 | udev_monitor->snl_destination.nl.nl_family = AF_NETLINK; |
218 | udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV; | |
912541b0 | 219 | |
912541b0 | 220 | return udev_monitor; |
1c7047ea KS |
221 | } |
222 | ||
7459bcdc KS |
223 | /** |
224 | * udev_monitor_new_from_netlink: | |
225 | * @udev: udev library context | |
226 | * @name: name of event source | |
227 | * | |
228 | * Create new udev monitor and connect to a specified event | |
229 | * source. Valid sources identifiers are "udev" and "kernel". | |
230 | * | |
231 | * Applications should usually not connect directly to the | |
232 | * "kernel" events, because the devices might not be useable | |
233 | * at that time, before udev has configured them, and created | |
50579295 KS |
234 | * device nodes. Accessing devices at the same time as udev, |
235 | * might result in unpredictable behavior. The "udev" events | |
236 | * are sent out after udev has finished its event processing, | |
237 | * all rules have been processed, and needed device nodes are | |
238 | * created. | |
7459bcdc KS |
239 | * |
240 | * The initial refcount is 1, and needs to be decremented to | |
241 | * release the resources of the udev monitor. | |
242 | * | |
243 | * Returns: a new udev monitor, or #NULL, in case of an error | |
244 | **/ | |
54cf0b7f | 245 | _public_ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) |
7459bcdc | 246 | { |
912541b0 | 247 | return udev_monitor_new_from_netlink_fd(udev, name, -1); |
7459bcdc KS |
248 | } |
249 | ||
e14bdd88 | 250 | static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i, |
912541b0 | 251 | unsigned short code, unsigned int data) |
e14bdd88 | 252 | { |
912541b0 | 253 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 254 | |
912541b0 KS |
255 | ins->code = code; |
256 | ins->k = data; | |
257 | (*i)++; | |
e14bdd88 KS |
258 | } |
259 | ||
260 | static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i, | |
912541b0 KS |
261 | unsigned short code, unsigned int data, |
262 | unsigned short jt, unsigned short jf) | |
e14bdd88 | 263 | { |
912541b0 | 264 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 265 | |
912541b0 KS |
266 | ins->code = code; |
267 | ins->jt = jt; | |
268 | ins->jf = jf; | |
269 | ins->k = data; | |
270 | (*i)++; | |
e14bdd88 KS |
271 | } |
272 | ||
ce1d6d7f KS |
273 | /** |
274 | * udev_monitor_filter_update: | |
275 | * @udev_monitor: monitor | |
276 | * | |
50579295 KS |
277 | * Update the installed socket filter. This is only needed, |
278 | * if the filter was removed or changed. | |
ce1d6d7f KS |
279 | * |
280 | * Returns: 0 on success, otherwise a negative error value. | |
281 | */ | |
54cf0b7f | 282 | _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor) |
e14bdd88 | 283 | { |
912541b0 KS |
284 | struct sock_filter ins[512]; |
285 | struct sock_fprog filter; | |
286 | unsigned int i; | |
287 | struct udev_list_entry *list_entry; | |
288 | int err; | |
289 | ||
290 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL && | |
291 | udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) | |
292 | return 0; | |
293 | ||
29804cc1 | 294 | memzero(ins, sizeof(ins)); |
912541b0 KS |
295 | i = 0; |
296 | ||
297 | /* load magic in A */ | |
298 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic)); | |
299 | /* jump if magic matches */ | |
300 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); | |
301 | /* wrong magic, pass packet */ | |
302 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
303 | ||
304 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) { | |
305 | int tag_matches; | |
306 | ||
307 | /* count tag matches, to calculate end of tag match block */ | |
308 | tag_matches = 0; | |
309 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) | |
310 | tag_matches++; | |
311 | ||
312 | /* add all tags matches */ | |
313 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
314 | uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
315 | uint32_t tag_bloom_hi = tag_bloom_bits >> 32; | |
316 | uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; | |
317 | ||
318 | /* load device bloom bits in A */ | |
319 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi)); | |
320 | /* clear bits (tag bits & bloom bits) */ | |
321 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); | |
322 | /* jump to next tag if it does not match */ | |
323 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); | |
324 | ||
325 | /* load device bloom bits in A */ | |
326 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo)); | |
327 | /* clear bits (tag bits & bloom bits) */ | |
328 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); | |
329 | /* jump behind end of tag match block if tag matches */ | |
330 | tag_matches--; | |
331 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); | |
332 | } | |
333 | ||
334 | /* nothing matched, drop packet */ | |
335 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
336 | } | |
337 | ||
338 | /* add all subsystem matches */ | |
339 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) { | |
340 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
341 | unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry)); | |
342 | ||
343 | /* load device subsystem value in A */ | |
344 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash)); | |
345 | if (udev_list_entry_get_value(list_entry) == NULL) { | |
346 | /* jump if subsystem does not match */ | |
347 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
348 | } else { | |
349 | /* jump if subsystem does not match */ | |
350 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); | |
351 | ||
352 | /* load device devtype value in A */ | |
353 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash)); | |
354 | /* jump if value does not match */ | |
355 | hash = util_string_hash32(udev_list_entry_get_value(list_entry)); | |
356 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
357 | } | |
358 | ||
359 | /* matched, pass packet */ | |
360 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
361 | ||
8fef0ff2 | 362 | if (i+1 >= ELEMENTSOF(ins)) |
994e0234 | 363 | return -E2BIG; |
912541b0 KS |
364 | } |
365 | ||
366 | /* nothing matched, drop packet */ | |
367 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
368 | } | |
369 | ||
370 | /* matched, pass packet */ | |
371 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
372 | ||
373 | /* install filter */ | |
29804cc1 | 374 | memzero(&filter, sizeof(filter)); |
912541b0 KS |
375 | filter.len = i; |
376 | filter.filter = ins; | |
377 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
994e0234 | 378 | return err < 0 ? -errno : 0; |
e14bdd88 KS |
379 | } |
380 | ||
1e03b754 KS |
381 | int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
382 | { | |
b49d9b50 | 383 | udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid; |
912541b0 | 384 | return 0; |
1e03b754 | 385 | } |
44daf75d | 386 | |
ce1d6d7f KS |
387 | /** |
388 | * udev_monitor_enable_receiving: | |
389 | * @udev_monitor: the monitor which should receive events | |
390 | * | |
391 | * Binds the @udev_monitor socket to the event source. | |
392 | * | |
393 | * Returns: 0 on success, otherwise a negative error value. | |
394 | */ | |
54cf0b7f | 395 | _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
d59f11e1 | 396 | { |
912541b0 KS |
397 | int err = 0; |
398 | const int on = 1; | |
399 | ||
2d13da88 KS |
400 | udev_monitor_filter_update(udev_monitor); |
401 | ||
402 | if (!udev_monitor->bound) { | |
403 | err = bind(udev_monitor->sock, | |
b49d9b50 | 404 | &udev_monitor->snl.sa, sizeof(struct sockaddr_nl)); |
2d13da88 KS |
405 | if (err == 0) |
406 | udev_monitor->bound = true; | |
912541b0 KS |
407 | } |
408 | ||
44daf75d TG |
409 | if (err >= 0) |
410 | monitor_set_nl_address(udev_monitor); | |
411 | else { | |
56f64d95 | 412 | log_debug_errno(errno, "bind failed: %m"); |
994e0234 | 413 | return -errno; |
912541b0 KS |
414 | } |
415 | ||
416 | /* enable receiving of sender credentials */ | |
9dedfe7f TG |
417 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); |
418 | if (err < 0) | |
56f64d95 | 419 | log_debug_errno(errno, "setting SO_PASSCRED failed: %m"); |
9dedfe7f | 420 | |
912541b0 | 421 | return 0; |
ba6929f6 KS |
422 | } |
423 | ||
f712894d KS |
424 | /** |
425 | * udev_monitor_set_receive_buffer_size: | |
426 | * @udev_monitor: the monitor which should receive events | |
427 | * @size: the size in bytes | |
428 | * | |
429 | * Set the size of the kernel socket buffer. This call needs the | |
430 | * appropriate privileges to succeed. | |
431 | * | |
432 | * Returns: 0 on success, otherwise -1 on error. | |
433 | */ | |
54cf0b7f | 434 | _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
cb25a958 | 435 | { |
912541b0 | 436 | if (udev_monitor == NULL) |
994e0234 | 437 | return -EINVAL; |
912541b0 | 438 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)); |
cb25a958 KS |
439 | } |
440 | ||
1e03b754 KS |
441 | int udev_monitor_disconnect(struct udev_monitor *udev_monitor) |
442 | { | |
912541b0 | 443 | int err; |
1e03b754 | 444 | |
912541b0 KS |
445 | err = close(udev_monitor->sock); |
446 | udev_monitor->sock = -1; | |
994e0234 | 447 | return err < 0 ? -errno : 0; |
1e03b754 KS |
448 | } |
449 | ||
7d8787b3 KS |
450 | /** |
451 | * udev_monitor_ref: | |
452 | * @udev_monitor: udev monitor | |
453 | * | |
454 | * Take a reference of a udev monitor. | |
455 | * | |
456 | * Returns: the passed udev monitor | |
457 | **/ | |
54cf0b7f | 458 | _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor) |
ba6929f6 | 459 | { |
912541b0 KS |
460 | if (udev_monitor == NULL) |
461 | return NULL; | |
462 | udev_monitor->refcount++; | |
463 | return udev_monitor; | |
ba6929f6 KS |
464 | } |
465 | ||
7d8787b3 KS |
466 | /** |
467 | * udev_monitor_unref: | |
468 | * @udev_monitor: udev monitor | |
469 | * | |
ff109b8d | 470 | * Drop a reference of a udev monitor. If the refcount reaches zero, |
be7de409 | 471 | * the bound socket will be closed, and the resources of the monitor |
7d8787b3 KS |
472 | * will be released. |
473 | * | |
725d7e6c | 474 | * Returns: #NULL |
7d8787b3 | 475 | **/ |
20bbd54f | 476 | _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor) |
ba6929f6 | 477 | { |
912541b0 | 478 | if (udev_monitor == NULL) |
20bbd54f | 479 | return NULL; |
912541b0 KS |
480 | udev_monitor->refcount--; |
481 | if (udev_monitor->refcount > 0) | |
725d7e6c | 482 | return NULL; |
912541b0 KS |
483 | if (udev_monitor->sock >= 0) |
484 | close(udev_monitor->sock); | |
485 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); | |
486 | udev_list_cleanup(&udev_monitor->filter_tag_list); | |
912541b0 | 487 | free(udev_monitor); |
20bbd54f | 488 | return NULL; |
ba6929f6 KS |
489 | } |
490 | ||
7d8787b3 KS |
491 | /** |
492 | * udev_monitor_get_udev: | |
493 | * @udev_monitor: udev monitor | |
494 | * | |
b98fd840 | 495 | * Retrieve the udev library context the monitor was created with. |
7d8787b3 KS |
496 | * |
497 | * Returns: the udev library context | |
498 | **/ | |
54cf0b7f | 499 | _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor) |
ba6929f6 | 500 | { |
912541b0 KS |
501 | if (udev_monitor == NULL) |
502 | return NULL; | |
503 | return udev_monitor->udev; | |
ba6929f6 KS |
504 | } |
505 | ||
7d8787b3 KS |
506 | /** |
507 | * udev_monitor_get_fd: | |
508 | * @udev_monitor: udev monitor | |
509 | * | |
510 | * Retrieve the socket file descriptor associated with the monitor. | |
511 | * | |
512 | * Returns: the socket file descriptor | |
513 | **/ | |
54cf0b7f | 514 | _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
ba6929f6 | 515 | { |
912541b0 | 516 | if (udev_monitor == NULL) |
994e0234 | 517 | return -EINVAL; |
912541b0 | 518 | return udev_monitor->sock; |
ba6929f6 KS |
519 | } |
520 | ||
e14bdd88 KS |
521 | static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device) |
522 | { | |
912541b0 KS |
523 | struct udev_list_entry *list_entry; |
524 | ||
525 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL) | |
526 | goto tag; | |
527 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
528 | const char *subsys = udev_list_entry_get_name(list_entry); | |
529 | const char *dsubsys = udev_device_get_subsystem(udev_device); | |
530 | const char *devtype; | |
531 | const char *ddevtype; | |
532 | ||
090be865 | 533 | if (!streq(dsubsys, subsys)) |
912541b0 KS |
534 | continue; |
535 | ||
536 | devtype = udev_list_entry_get_value(list_entry); | |
537 | if (devtype == NULL) | |
538 | goto tag; | |
539 | ddevtype = udev_device_get_devtype(udev_device); | |
540 | if (ddevtype == NULL) | |
541 | continue; | |
090be865 | 542 | if (streq(ddevtype, devtype)) |
912541b0 KS |
543 | goto tag; |
544 | } | |
545 | return 0; | |
28460195 KS |
546 | |
547 | tag: | |
912541b0 KS |
548 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) |
549 | return 1; | |
550 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
551 | const char *tag = udev_list_entry_get_name(list_entry); | |
552 | ||
553 | if (udev_device_has_tag(udev_device, tag)) | |
554 | return 1; | |
555 | } | |
556 | return 0; | |
e14bdd88 KS |
557 | } |
558 | ||
7d8787b3 | 559 | /** |
d59f11e1 | 560 | * udev_monitor_receive_device: |
7d8787b3 KS |
561 | * @udev_monitor: udev monitor |
562 | * | |
d59f11e1 | 563 | * Receive data from the udev monitor socket, allocate a new udev |
b98fd840 | 564 | * device, fill in the received data, and return the device. |
7d8787b3 | 565 | * |
50579295 | 566 | * Only socket connections with uid=0 are accepted. |
7d8787b3 | 567 | * |
b30b4260 KS |
568 | * The monitor socket is by default set to NONBLOCK. A variant of poll() on |
569 | * the file descriptor returned by udev_monitor_get_fd() should to be used to | |
570 | * wake up when new devices arrive, or alternatively the file descriptor | |
571 | * switched into blocking mode. | |
572 | * | |
7d8787b3 | 573 | * The initial refcount is 1, and needs to be decremented to |
be7de409 | 574 | * release the resources of the udev device. |
7d8787b3 KS |
575 | * |
576 | * Returns: a new udev device, or #NULL, in case of an error | |
577 | **/ | |
54cf0b7f | 578 | _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor) |
ba6929f6 | 579 | { |
912541b0 KS |
580 | struct udev_device *udev_device; |
581 | struct msghdr smsg; | |
582 | struct iovec iov; | |
583 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
584 | struct cmsghdr *cmsg; | |
b49d9b50 | 585 | union sockaddr_union snl; |
912541b0 | 586 | struct ucred *cred; |
bf3dd6b1 SL |
587 | union { |
588 | struct udev_monitor_netlink_header nlh; | |
589 | char raw[8192]; | |
590 | } buf; | |
912541b0 KS |
591 | ssize_t buflen; |
592 | ssize_t bufpos; | |
2df959ec | 593 | bool is_initialized = false; |
ba6929f6 | 594 | |
e14bdd88 | 595 | retry: |
912541b0 KS |
596 | if (udev_monitor == NULL) |
597 | return NULL; | |
912541b0 KS |
598 | iov.iov_base = &buf; |
599 | iov.iov_len = sizeof(buf); | |
29804cc1 | 600 | memzero(&smsg, sizeof(struct msghdr)); |
912541b0 KS |
601 | smsg.msg_iov = &iov; |
602 | smsg.msg_iovlen = 1; | |
603 | smsg.msg_control = cred_msg; | |
604 | smsg.msg_controllen = sizeof(cred_msg); | |
f6613dd9 KS |
605 | smsg.msg_name = &snl; |
606 | smsg.msg_namelen = sizeof(snl); | |
912541b0 | 607 | |
a38d9945 | 608 | buflen = recvmsg(udev_monitor->sock, &smsg, 0); |
912541b0 KS |
609 | if (buflen < 0) { |
610 | if (errno != EINTR) | |
ff49bc32 | 611 | log_debug("unable to receive message"); |
912541b0 KS |
612 | return NULL; |
613 | } | |
614 | ||
9c89c1ca | 615 | if (buflen < 32 || (smsg.msg_flags & MSG_TRUNC)) { |
ff49bc32 | 616 | log_debug("invalid message length"); |
912541b0 KS |
617 | return NULL; |
618 | } | |
619 | ||
f6613dd9 KS |
620 | if (snl.nl.nl_groups == 0) { |
621 | /* unicast message, check if we trust the sender */ | |
622 | if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 || | |
623 | snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) { | |
ff49bc32 | 624 | log_debug("unicast netlink message ignored"); |
f6613dd9 KS |
625 | return NULL; |
626 | } | |
627 | } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) { | |
628 | if (snl.nl.nl_pid > 0) { | |
1fa2f38f ZJS |
629 | log_debug("multicast kernel netlink message from PID %"PRIu32" ignored", |
630 | snl.nl.nl_pid); | |
f6613dd9 | 631 | return NULL; |
912541b0 KS |
632 | } |
633 | } | |
634 | ||
635 | cmsg = CMSG_FIRSTHDR(&smsg); | |
636 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
ff49bc32 | 637 | log_debug("no sender credentials received, message ignored"); |
912541b0 KS |
638 | return NULL; |
639 | } | |
640 | ||
641 | cred = (struct ucred *)CMSG_DATA(cmsg); | |
642 | if (cred->uid != 0) { | |
1fa2f38f | 643 | log_debug("sender uid="UID_FMT", message ignored", cred->uid); |
912541b0 KS |
644 | return NULL; |
645 | } | |
646 | ||
bf3dd6b1 | 647 | if (memcmp(buf.raw, "libudev", 8) == 0) { |
912541b0 | 648 | /* udev message needs proper version magic */ |
bf3dd6b1 | 649 | if (buf.nlh.magic != htonl(UDEV_MONITOR_MAGIC)) { |
ff49bc32 | 650 | log_debug("unrecognized message signature (%x != %x)", |
bf3dd6b1 | 651 | buf.nlh.magic, htonl(UDEV_MONITOR_MAGIC)); |
912541b0 KS |
652 | return NULL; |
653 | } | |
bf3dd6b1 | 654 | if (buf.nlh.properties_off+32 > (size_t)buflen) { |
e6ac88dd TG |
655 | log_debug("message smaller than expected (%u > %zd)", |
656 | buf.nlh.properties_off+32, buflen); | |
912541b0 | 657 | return NULL; |
f6613dd9 KS |
658 | } |
659 | ||
bf3dd6b1 | 660 | bufpos = buf.nlh.properties_off; |
f6613dd9 KS |
661 | |
662 | /* devices received from udev are always initialized */ | |
2df959ec | 663 | is_initialized = true; |
912541b0 KS |
664 | } else { |
665 | /* kernel message with header */ | |
bf3dd6b1 | 666 | bufpos = strlen(buf.raw) + 1; |
912541b0 | 667 | if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { |
ff49bc32 | 668 | log_debug("invalid message length"); |
912541b0 KS |
669 | return NULL; |
670 | } | |
671 | ||
672 | /* check message header */ | |
bf3dd6b1 | 673 | if (strstr(buf.raw, "@/") == NULL) { |
ff49bc32 | 674 | log_debug("unrecognized message header"); |
912541b0 KS |
675 | return NULL; |
676 | } | |
677 | } | |
678 | ||
2df959ec | 679 | udev_device = udev_device_new_from_nulstr(udev_monitor->udev, &buf.raw[bufpos], buflen - bufpos); |
e6ac88dd TG |
680 | if (!udev_device) { |
681 | log_debug("could not create device: %m"); | |
912541b0 | 682 | return NULL; |
e6ac88dd | 683 | } |
2df959ec TG |
684 | |
685 | if (is_initialized) | |
686 | udev_device_set_is_initialized(udev_device); | |
912541b0 KS |
687 | |
688 | /* skip device, if it does not pass the current filter */ | |
689 | if (!passes_filter(udev_monitor, udev_device)) { | |
690 | struct pollfd pfd[1]; | |
691 | int rc; | |
692 | ||
693 | udev_device_unref(udev_device); | |
694 | ||
695 | /* if something is queued, get next device */ | |
696 | pfd[0].fd = udev_monitor->sock; | |
697 | pfd[0].events = POLLIN; | |
698 | rc = poll(pfd, 1, 0); | |
699 | if (rc > 0) | |
700 | goto retry; | |
701 | return NULL; | |
702 | } | |
703 | ||
704 | return udev_device; | |
ba6929f6 | 705 | } |
9925ab04 | 706 | |
1e03b754 | 707 | int udev_monitor_send_device(struct udev_monitor *udev_monitor, |
912541b0 | 708 | struct udev_monitor *destination, struct udev_device *udev_device) |
9925ab04 | 709 | { |
81b9fe54 ZJS |
710 | const char *buf, *val; |
711 | ssize_t blen, count; | |
712 | struct udev_monitor_netlink_header nlh = { | |
713 | .prefix = "libudev", | |
714 | .magic = htonl(UDEV_MONITOR_MAGIC), | |
715 | .header_size = sizeof nlh, | |
716 | }; | |
717 | struct iovec iov[2] = { | |
718 | { .iov_base = &nlh, .iov_len = sizeof nlh }, | |
719 | }; | |
720 | struct msghdr smsg = { | |
721 | .msg_iov = iov, | |
722 | .msg_iovlen = 2, | |
723 | }; | |
2d13da88 KS |
724 | struct udev_list_entry *list_entry; |
725 | uint64_t tag_bloom_bits; | |
726 | ||
912541b0 | 727 | blen = udev_device_get_properties_monitor_buf(udev_device, &buf); |
e6ac88dd TG |
728 | if (blen < 32) { |
729 | log_debug("device buffer is too small to contain a valid device"); | |
912541b0 | 730 | return -EINVAL; |
e6ac88dd | 731 | } |
912541b0 | 732 | |
81b9fe54 | 733 | /* fill in versioned header */ |
2d13da88 KS |
734 | val = udev_device_get_subsystem(udev_device); |
735 | nlh.filter_subsystem_hash = htonl(util_string_hash32(val)); | |
81b9fe54 | 736 | |
2d13da88 KS |
737 | val = udev_device_get_devtype(udev_device); |
738 | if (val != NULL) | |
739 | nlh.filter_devtype_hash = htonl(util_string_hash32(val)); | |
2d13da88 KS |
740 | |
741 | /* add tag bloom filter */ | |
742 | tag_bloom_bits = 0; | |
743 | udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device)) | |
744 | tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
745 | if (tag_bloom_bits > 0) { | |
746 | nlh.filter_tag_bloom_hi = htonl(tag_bloom_bits >> 32); | |
747 | nlh.filter_tag_bloom_lo = htonl(tag_bloom_bits & 0xffffffff); | |
912541b0 KS |
748 | } |
749 | ||
2d13da88 KS |
750 | /* add properties list */ |
751 | nlh.properties_off = iov[0].iov_len; | |
752 | nlh.properties_len = blen; | |
753 | iov[1].iov_base = (char *)buf; | |
754 | iov[1].iov_len = blen; | |
912541b0 | 755 | |
2d13da88 KS |
756 | /* |
757 | * Use custom address for target, or the default one. | |
758 | * | |
759 | * If we send to a multicast group, we will get | |
760 | * ECONNREFUSED, which is expected. | |
761 | */ | |
a4445e88 | 762 | if (destination) |
2d13da88 KS |
763 | smsg.msg_name = &destination->snl; |
764 | else | |
765 | smsg.msg_name = &udev_monitor->snl_destination; | |
766 | smsg.msg_namelen = sizeof(struct sockaddr_nl); | |
767 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
a4445e88 TG |
768 | if (count < 0) { |
769 | if (!destination && errno == ECONNREFUSED) { | |
7800bf71 | 770 | log_debug("passed device to netlink monitor %p", udev_monitor); |
a4445e88 TG |
771 | return 0; |
772 | } else | |
773 | return -errno; | |
774 | } | |
775 | ||
965288c5 | 776 | log_debug("passed %zi byte device to netlink monitor %p", count, udev_monitor); |
2d13da88 | 777 | return count; |
9925ab04 | 778 | } |
e14bdd88 | 779 | |
ce1d6d7f KS |
780 | /** |
781 | * udev_monitor_filter_add_match_subsystem_devtype: | |
782 | * @udev_monitor: the monitor | |
783 | * @subsystem: the subsystem value to match the incoming devices against | |
214a6c79 | 784 | * @devtype: the devtype value to match the incoming devices against |
ce1d6d7f | 785 | * |
50579295 | 786 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
787 | * will usually not be woken up for devices which do not match. |
788 | * | |
ce1d6d7f KS |
789 | * The filter must be installed before the monitor is switched to listening mode. |
790 | * | |
791 | * Returns: 0 on success, otherwise a negative error value. | |
792 | */ | |
54cf0b7f | 793 | _public_ int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype) |
e14bdd88 | 794 | { |
912541b0 KS |
795 | if (udev_monitor == NULL) |
796 | return -EINVAL; | |
797 | if (subsystem == NULL) | |
798 | return -EINVAL; | |
799 | if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL) | |
800 | return -ENOMEM; | |
801 | return 0; | |
e14bdd88 | 802 | } |
08a7a795 | 803 | |
28460195 KS |
804 | /** |
805 | * udev_monitor_filter_add_match_tag: | |
806 | * @udev_monitor: the monitor | |
807 | * @tag: the name of a tag | |
808 | * | |
50579295 | 809 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
810 | * will usually not be woken up for devices which do not match. |
811 | * | |
812 | * The filter must be installed before the monitor is switched to listening mode. | |
813 | * | |
814 | * Returns: 0 on success, otherwise a negative error value. | |
815 | */ | |
54cf0b7f | 816 | _public_ int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag) |
28460195 | 817 | { |
912541b0 KS |
818 | if (udev_monitor == NULL) |
819 | return -EINVAL; | |
820 | if (tag == NULL) | |
821 | return -EINVAL; | |
822 | if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL) | |
823 | return -ENOMEM; | |
824 | return 0; | |
28460195 KS |
825 | } |
826 | ||
ce1d6d7f KS |
827 | /** |
828 | * udev_monitor_filter_remove: | |
829 | * @udev_monitor: monitor | |
830 | * | |
831 | * Remove all filters from monitor. | |
832 | * | |
833 | * Returns: 0 on success, otherwise a negative error value. | |
834 | */ | |
54cf0b7f | 835 | _public_ int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
08a7a795 | 836 | { |
912541b0 | 837 | static struct sock_fprog filter = { 0, NULL }; |
08a7a795 | 838 | |
912541b0 KS |
839 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
840 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
08a7a795 | 841 | } |