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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 | 30 | |
b4bbcaa9 TA |
31 | #include "libudev.h" |
32 | ||
b5efdb8a | 33 | #include "alloc-util.h" |
3ffd4af2 | 34 | #include "fd-util.h" |
0d39fa9c | 35 | #include "fileio.h" |
07630cea | 36 | #include "formats-util.h" |
ba6929f6 | 37 | #include "libudev-private.h" |
df32a1ca | 38 | #include "missing.h" |
4e036b7a | 39 | #include "mount-util.h" |
07630cea LP |
40 | #include "socket-util.h" |
41 | #include "string-util.h" | |
ba6929f6 | 42 | |
ce1d6d7f KS |
43 | /** |
44 | * SECTION:libudev-monitor | |
45 | * @short_description: device event source | |
46 | * | |
47 | * Connects to a device event source. | |
48 | */ | |
49 | ||
ce1d6d7f KS |
50 | /** |
51 | * udev_monitor: | |
52 | * | |
50579295 | 53 | * Opaque object handling an event source. |
ce1d6d7f | 54 | */ |
ba6929f6 | 55 | struct udev_monitor { |
912541b0 KS |
56 | struct udev *udev; |
57 | int refcount; | |
58 | int sock; | |
b49d9b50 KS |
59 | union sockaddr_union snl; |
60 | union sockaddr_union snl_trusted_sender; | |
61 | union sockaddr_union snl_destination; | |
912541b0 KS |
62 | socklen_t addrlen; |
63 | struct udev_list filter_subsystem_list; | |
64 | struct udev_list filter_tag_list; | |
65 | bool bound; | |
ba6929f6 KS |
66 | }; |
67 | ||
f2b93744 | 68 | enum udev_monitor_netlink_group { |
912541b0 KS |
69 | UDEV_MONITOR_NONE, |
70 | UDEV_MONITOR_KERNEL, | |
71 | UDEV_MONITOR_UDEV, | |
f2b93744 KS |
72 | }; |
73 | ||
912541b0 | 74 | #define UDEV_MONITOR_MAGIC 0xfeedcafe |
e14bdd88 | 75 | struct udev_monitor_netlink_header { |
912541b0 KS |
76 | /* "libudev" prefix to distinguish libudev and kernel messages */ |
77 | char prefix[8]; | |
78 | /* | |
79 | * magic to protect against daemon <-> library message format mismatch | |
80 | * used in the kernel from socket filter rules; needs to be stored in network order | |
81 | */ | |
82 | unsigned int magic; | |
83 | /* total length of header structure known to the sender */ | |
84 | unsigned int header_size; | |
85 | /* properties string buffer */ | |
86 | unsigned int properties_off; | |
87 | unsigned int properties_len; | |
88 | /* | |
89 | * hashes of primary device properties strings, to let libudev subscribers | |
90 | * use in-kernel socket filters; values need to be stored in network order | |
91 | */ | |
92 | unsigned int filter_subsystem_hash; | |
93 | unsigned int filter_devtype_hash; | |
94 | unsigned int filter_tag_bloom_hi; | |
95 | unsigned int filter_tag_bloom_lo; | |
e14bdd88 KS |
96 | }; |
97 | ||
98 | static struct udev_monitor *udev_monitor_new(struct udev *udev) | |
99 | { | |
912541b0 KS |
100 | struct udev_monitor *udev_monitor; |
101 | ||
955d98c9 | 102 | udev_monitor = new0(struct udev_monitor, 1); |
912541b0 KS |
103 | if (udev_monitor == NULL) |
104 | return NULL; | |
105 | udev_monitor->refcount = 1; | |
106 | udev_monitor->udev = udev; | |
107 | udev_list_init(udev, &udev_monitor->filter_subsystem_list, false); | |
108 | udev_list_init(udev, &udev_monitor->filter_tag_list, true); | |
109 | return udev_monitor; | |
e14bdd88 KS |
110 | } |
111 | ||
df32a1ca KS |
112 | /* we consider udev running when /dev is on devtmpfs */ |
113 | static bool udev_has_devtmpfs(struct udev *udev) { | |
21749924 | 114 | |
2695c5c4 | 115 | union file_handle_union h = FILE_HANDLE_INIT; |
df32a1ca KS |
116 | _cleanup_fclose_ FILE *f = NULL; |
117 | char line[LINE_MAX], *e; | |
21749924 | 118 | int mount_id; |
df32a1ca KS |
119 | int r; |
120 | ||
370c860f | 121 | r = name_to_handle_at(AT_FDCWD, "/dev", &h.handle, &mount_id, 0); |
e6c47472 ZJS |
122 | if (r < 0) { |
123 | if (errno != EOPNOTSUPP) | |
56f64d95 | 124 | log_debug_errno(errno, "name_to_handle_at on /dev: %m"); |
df32a1ca | 125 | return false; |
e6c47472 | 126 | } |
df32a1ca | 127 | |
df32a1ca KS |
128 | f = fopen("/proc/self/mountinfo", "re"); |
129 | if (!f) | |
130 | return false; | |
131 | ||
132 | FOREACH_LINE(line, f, return false) { | |
df32a1ca KS |
133 | int mid; |
134 | ||
135 | if (sscanf(line, "%i", &mid) != 1) | |
136 | continue; | |
137 | ||
138 | if (mid != mount_id) | |
139 | continue; | |
140 | ||
141 | e = strstr(line, " - "); | |
142 | if (!e) | |
143 | continue; | |
144 | ||
145 | /* accept any name that starts with the currently expected type */ | |
146 | if (startswith(e + 3, "devtmpfs")) | |
147 | return true; | |
148 | } | |
149 | ||
150 | return false; | |
151 | } | |
152 | ||
44daf75d TG |
153 | static void monitor_set_nl_address(struct udev_monitor *udev_monitor) { |
154 | union sockaddr_union snl; | |
155 | socklen_t addrlen; | |
156 | int r; | |
157 | ||
158 | assert(udev_monitor); | |
159 | ||
160 | /* get the address the kernel has assigned us | |
161 | * it is usually, but not necessarily the pid | |
162 | */ | |
163 | addrlen = sizeof(struct sockaddr_nl); | |
164 | r = getsockname(udev_monitor->sock, &snl.sa, &addrlen); | |
165 | if (r >= 0) | |
166 | udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid; | |
167 | } | |
168 | ||
7459bcdc | 169 | struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) |
1c7047ea | 170 | { |
912541b0 KS |
171 | struct udev_monitor *udev_monitor; |
172 | unsigned int group; | |
173 | ||
174 | if (udev == NULL) | |
175 | return NULL; | |
176 | ||
177 | if (name == NULL) | |
178 | group = UDEV_MONITOR_NONE; | |
e8a3b2dc KS |
179 | else if (streq(name, "udev")) { |
180 | /* | |
181 | * We do not support subscribing to uevents if no instance of | |
182 | * udev is running. Uevents would otherwise broadcast the | |
183 | * processing data of the host into containers, which is not | |
184 | * desired. | |
185 | * | |
186 | * Containers will currently not get any udev uevents, until | |
187 | * a supporting infrastructure is available. | |
188 | * | |
189 | * We do not set a netlink multicast group here, so the socket | |
190 | * will not receive any messages. | |
191 | */ | |
9ea28c55 | 192 | if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) { |
ff49bc32 | 193 | log_debug("the udev service seems not to be active, disable the monitor"); |
e8a3b2dc KS |
194 | group = UDEV_MONITOR_NONE; |
195 | } else | |
196 | group = UDEV_MONITOR_UDEV; | |
197 | } else if (streq(name, "kernel")) | |
912541b0 KS |
198 | group = UDEV_MONITOR_KERNEL; |
199 | else | |
200 | return NULL; | |
201 | ||
202 | udev_monitor = udev_monitor_new(udev); | |
203 | if (udev_monitor == NULL) | |
204 | return NULL; | |
205 | ||
206 | if (fd < 0) { | |
207 | udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); | |
44daf75d | 208 | if (udev_monitor->sock < 0) { |
56f64d95 | 209 | log_debug_errno(errno, "error getting socket: %m"); |
6b430fdb | 210 | return mfree(udev_monitor); |
912541b0 KS |
211 | } |
212 | } else { | |
213 | udev_monitor->bound = true; | |
214 | udev_monitor->sock = fd; | |
44daf75d | 215 | monitor_set_nl_address(udev_monitor); |
912541b0 KS |
216 | } |
217 | ||
b49d9b50 KS |
218 | udev_monitor->snl.nl.nl_family = AF_NETLINK; |
219 | udev_monitor->snl.nl.nl_groups = group; | |
912541b0 KS |
220 | |
221 | /* default destination for sending */ | |
b49d9b50 KS |
222 | udev_monitor->snl_destination.nl.nl_family = AF_NETLINK; |
223 | udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV; | |
912541b0 | 224 | |
912541b0 | 225 | return udev_monitor; |
1c7047ea KS |
226 | } |
227 | ||
7459bcdc KS |
228 | /** |
229 | * udev_monitor_new_from_netlink: | |
230 | * @udev: udev library context | |
231 | * @name: name of event source | |
232 | * | |
233 | * Create new udev monitor and connect to a specified event | |
234 | * source. Valid sources identifiers are "udev" and "kernel". | |
235 | * | |
236 | * Applications should usually not connect directly to the | |
237 | * "kernel" events, because the devices might not be useable | |
238 | * at that time, before udev has configured them, and created | |
50579295 KS |
239 | * device nodes. Accessing devices at the same time as udev, |
240 | * might result in unpredictable behavior. The "udev" events | |
241 | * are sent out after udev has finished its event processing, | |
242 | * all rules have been processed, and needed device nodes are | |
243 | * created. | |
7459bcdc KS |
244 | * |
245 | * The initial refcount is 1, and needs to be decremented to | |
246 | * release the resources of the udev monitor. | |
247 | * | |
248 | * Returns: a new udev monitor, or #NULL, in case of an error | |
249 | **/ | |
54cf0b7f | 250 | _public_ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) |
7459bcdc | 251 | { |
912541b0 | 252 | return udev_monitor_new_from_netlink_fd(udev, name, -1); |
7459bcdc KS |
253 | } |
254 | ||
e14bdd88 | 255 | static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i, |
912541b0 | 256 | unsigned short code, unsigned int data) |
e14bdd88 | 257 | { |
912541b0 | 258 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 259 | |
912541b0 KS |
260 | ins->code = code; |
261 | ins->k = data; | |
262 | (*i)++; | |
e14bdd88 KS |
263 | } |
264 | ||
265 | static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i, | |
912541b0 KS |
266 | unsigned short code, unsigned int data, |
267 | unsigned short jt, unsigned short jf) | |
e14bdd88 | 268 | { |
912541b0 | 269 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 270 | |
912541b0 KS |
271 | ins->code = code; |
272 | ins->jt = jt; | |
273 | ins->jf = jf; | |
274 | ins->k = data; | |
275 | (*i)++; | |
e14bdd88 KS |
276 | } |
277 | ||
ce1d6d7f KS |
278 | /** |
279 | * udev_monitor_filter_update: | |
280 | * @udev_monitor: monitor | |
281 | * | |
50579295 KS |
282 | * Update the installed socket filter. This is only needed, |
283 | * if the filter was removed or changed. | |
ce1d6d7f KS |
284 | * |
285 | * Returns: 0 on success, otherwise a negative error value. | |
286 | */ | |
54cf0b7f | 287 | _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor) |
e14bdd88 | 288 | { |
912541b0 KS |
289 | struct sock_filter ins[512]; |
290 | struct sock_fprog filter; | |
291 | unsigned int i; | |
292 | struct udev_list_entry *list_entry; | |
293 | int err; | |
294 | ||
295 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL && | |
296 | udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) | |
297 | return 0; | |
298 | ||
29804cc1 | 299 | memzero(ins, sizeof(ins)); |
912541b0 KS |
300 | i = 0; |
301 | ||
302 | /* load magic in A */ | |
303 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic)); | |
304 | /* jump if magic matches */ | |
305 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); | |
306 | /* wrong magic, pass packet */ | |
307 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
308 | ||
309 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) { | |
310 | int tag_matches; | |
311 | ||
312 | /* count tag matches, to calculate end of tag match block */ | |
313 | tag_matches = 0; | |
314 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) | |
315 | tag_matches++; | |
316 | ||
317 | /* add all tags matches */ | |
318 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
319 | uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
320 | uint32_t tag_bloom_hi = tag_bloom_bits >> 32; | |
321 | uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; | |
322 | ||
323 | /* load device bloom bits in A */ | |
324 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi)); | |
325 | /* clear bits (tag bits & bloom bits) */ | |
326 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); | |
327 | /* jump to next tag if it does not match */ | |
328 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); | |
329 | ||
330 | /* load device bloom bits in A */ | |
331 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo)); | |
332 | /* clear bits (tag bits & bloom bits) */ | |
333 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); | |
334 | /* jump behind end of tag match block if tag matches */ | |
335 | tag_matches--; | |
336 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); | |
337 | } | |
338 | ||
339 | /* nothing matched, drop packet */ | |
340 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
341 | } | |
342 | ||
343 | /* add all subsystem matches */ | |
344 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) { | |
345 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
346 | unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry)); | |
347 | ||
348 | /* load device subsystem value in A */ | |
349 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash)); | |
350 | if (udev_list_entry_get_value(list_entry) == NULL) { | |
351 | /* jump if subsystem does not match */ | |
352 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
353 | } else { | |
354 | /* jump if subsystem does not match */ | |
355 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); | |
356 | ||
357 | /* load device devtype value in A */ | |
358 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash)); | |
359 | /* jump if value does not match */ | |
360 | hash = util_string_hash32(udev_list_entry_get_value(list_entry)); | |
361 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
362 | } | |
363 | ||
364 | /* matched, pass packet */ | |
365 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
366 | ||
8fef0ff2 | 367 | if (i+1 >= ELEMENTSOF(ins)) |
994e0234 | 368 | return -E2BIG; |
912541b0 KS |
369 | } |
370 | ||
371 | /* nothing matched, drop packet */ | |
372 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
373 | } | |
374 | ||
375 | /* matched, pass packet */ | |
376 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
377 | ||
378 | /* install filter */ | |
29804cc1 | 379 | memzero(&filter, sizeof(filter)); |
912541b0 KS |
380 | filter.len = i; |
381 | filter.filter = ins; | |
382 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
994e0234 | 383 | return err < 0 ? -errno : 0; |
e14bdd88 KS |
384 | } |
385 | ||
1e03b754 KS |
386 | int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
387 | { | |
b49d9b50 | 388 | udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid; |
912541b0 | 389 | return 0; |
1e03b754 | 390 | } |
44daf75d | 391 | |
ce1d6d7f KS |
392 | /** |
393 | * udev_monitor_enable_receiving: | |
394 | * @udev_monitor: the monitor which should receive events | |
395 | * | |
396 | * Binds the @udev_monitor socket to the event source. | |
397 | * | |
398 | * Returns: 0 on success, otherwise a negative error value. | |
399 | */ | |
54cf0b7f | 400 | _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
d59f11e1 | 401 | { |
912541b0 KS |
402 | int err = 0; |
403 | const int on = 1; | |
404 | ||
2d13da88 KS |
405 | udev_monitor_filter_update(udev_monitor); |
406 | ||
407 | if (!udev_monitor->bound) { | |
408 | err = bind(udev_monitor->sock, | |
b49d9b50 | 409 | &udev_monitor->snl.sa, sizeof(struct sockaddr_nl)); |
2d13da88 KS |
410 | if (err == 0) |
411 | udev_monitor->bound = true; | |
912541b0 KS |
412 | } |
413 | ||
44daf75d TG |
414 | if (err >= 0) |
415 | monitor_set_nl_address(udev_monitor); | |
e1427b13 MS |
416 | else |
417 | return log_debug_errno(errno, "bind failed: %m"); | |
912541b0 KS |
418 | |
419 | /* enable receiving of sender credentials */ | |
9dedfe7f TG |
420 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); |
421 | if (err < 0) | |
56f64d95 | 422 | log_debug_errno(errno, "setting SO_PASSCRED failed: %m"); |
9dedfe7f | 423 | |
912541b0 | 424 | return 0; |
ba6929f6 KS |
425 | } |
426 | ||
f712894d KS |
427 | /** |
428 | * udev_monitor_set_receive_buffer_size: | |
429 | * @udev_monitor: the monitor which should receive events | |
430 | * @size: the size in bytes | |
431 | * | |
432 | * Set the size of the kernel socket buffer. This call needs the | |
433 | * appropriate privileges to succeed. | |
434 | * | |
435 | * Returns: 0 on success, otherwise -1 on error. | |
436 | */ | |
54cf0b7f | 437 | _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
cb25a958 | 438 | { |
912541b0 | 439 | if (udev_monitor == NULL) |
994e0234 | 440 | return -EINVAL; |
912541b0 | 441 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)); |
cb25a958 KS |
442 | } |
443 | ||
1e03b754 KS |
444 | int udev_monitor_disconnect(struct udev_monitor *udev_monitor) |
445 | { | |
912541b0 | 446 | int err; |
1e03b754 | 447 | |
912541b0 KS |
448 | err = close(udev_monitor->sock); |
449 | udev_monitor->sock = -1; | |
994e0234 | 450 | return err < 0 ? -errno : 0; |
1e03b754 KS |
451 | } |
452 | ||
7d8787b3 KS |
453 | /** |
454 | * udev_monitor_ref: | |
455 | * @udev_monitor: udev monitor | |
456 | * | |
457 | * Take a reference of a udev monitor. | |
458 | * | |
459 | * Returns: the passed udev monitor | |
460 | **/ | |
54cf0b7f | 461 | _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor) |
ba6929f6 | 462 | { |
912541b0 KS |
463 | if (udev_monitor == NULL) |
464 | return NULL; | |
465 | udev_monitor->refcount++; | |
466 | return udev_monitor; | |
ba6929f6 KS |
467 | } |
468 | ||
7d8787b3 KS |
469 | /** |
470 | * udev_monitor_unref: | |
471 | * @udev_monitor: udev monitor | |
472 | * | |
ff109b8d | 473 | * Drop a reference of a udev monitor. If the refcount reaches zero, |
be7de409 | 474 | * the bound socket will be closed, and the resources of the monitor |
7d8787b3 KS |
475 | * will be released. |
476 | * | |
725d7e6c | 477 | * Returns: #NULL |
7d8787b3 | 478 | **/ |
20bbd54f | 479 | _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor) |
ba6929f6 | 480 | { |
912541b0 | 481 | if (udev_monitor == NULL) |
20bbd54f | 482 | return NULL; |
912541b0 KS |
483 | udev_monitor->refcount--; |
484 | if (udev_monitor->refcount > 0) | |
725d7e6c | 485 | return NULL; |
912541b0 KS |
486 | if (udev_monitor->sock >= 0) |
487 | close(udev_monitor->sock); | |
488 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); | |
489 | udev_list_cleanup(&udev_monitor->filter_tag_list); | |
912541b0 | 490 | free(udev_monitor); |
20bbd54f | 491 | return NULL; |
ba6929f6 KS |
492 | } |
493 | ||
7d8787b3 KS |
494 | /** |
495 | * udev_monitor_get_udev: | |
496 | * @udev_monitor: udev monitor | |
497 | * | |
b98fd840 | 498 | * Retrieve the udev library context the monitor was created with. |
7d8787b3 KS |
499 | * |
500 | * Returns: the udev library context | |
501 | **/ | |
54cf0b7f | 502 | _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor) |
ba6929f6 | 503 | { |
912541b0 KS |
504 | if (udev_monitor == NULL) |
505 | return NULL; | |
506 | return udev_monitor->udev; | |
ba6929f6 KS |
507 | } |
508 | ||
7d8787b3 KS |
509 | /** |
510 | * udev_monitor_get_fd: | |
511 | * @udev_monitor: udev monitor | |
512 | * | |
513 | * Retrieve the socket file descriptor associated with the monitor. | |
514 | * | |
515 | * Returns: the socket file descriptor | |
516 | **/ | |
54cf0b7f | 517 | _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
ba6929f6 | 518 | { |
912541b0 | 519 | if (udev_monitor == NULL) |
994e0234 | 520 | return -EINVAL; |
912541b0 | 521 | return udev_monitor->sock; |
ba6929f6 KS |
522 | } |
523 | ||
e14bdd88 KS |
524 | static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device) |
525 | { | |
912541b0 KS |
526 | struct udev_list_entry *list_entry; |
527 | ||
528 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL) | |
529 | goto tag; | |
530 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
531 | const char *subsys = udev_list_entry_get_name(list_entry); | |
532 | const char *dsubsys = udev_device_get_subsystem(udev_device); | |
533 | const char *devtype; | |
534 | const char *ddevtype; | |
535 | ||
090be865 | 536 | if (!streq(dsubsys, subsys)) |
912541b0 KS |
537 | continue; |
538 | ||
539 | devtype = udev_list_entry_get_value(list_entry); | |
540 | if (devtype == NULL) | |
541 | goto tag; | |
542 | ddevtype = udev_device_get_devtype(udev_device); | |
543 | if (ddevtype == NULL) | |
544 | continue; | |
090be865 | 545 | if (streq(ddevtype, devtype)) |
912541b0 KS |
546 | goto tag; |
547 | } | |
548 | return 0; | |
28460195 KS |
549 | |
550 | tag: | |
912541b0 KS |
551 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) |
552 | return 1; | |
553 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
554 | const char *tag = udev_list_entry_get_name(list_entry); | |
555 | ||
556 | if (udev_device_has_tag(udev_device, tag)) | |
557 | return 1; | |
558 | } | |
559 | return 0; | |
e14bdd88 KS |
560 | } |
561 | ||
7d8787b3 | 562 | /** |
d59f11e1 | 563 | * udev_monitor_receive_device: |
7d8787b3 KS |
564 | * @udev_monitor: udev monitor |
565 | * | |
d59f11e1 | 566 | * Receive data from the udev monitor socket, allocate a new udev |
b98fd840 | 567 | * device, fill in the received data, and return the device. |
7d8787b3 | 568 | * |
50579295 | 569 | * Only socket connections with uid=0 are accepted. |
7d8787b3 | 570 | * |
b30b4260 KS |
571 | * The monitor socket is by default set to NONBLOCK. A variant of poll() on |
572 | * the file descriptor returned by udev_monitor_get_fd() should to be used to | |
573 | * wake up when new devices arrive, or alternatively the file descriptor | |
574 | * switched into blocking mode. | |
575 | * | |
7d8787b3 | 576 | * The initial refcount is 1, and needs to be decremented to |
be7de409 | 577 | * release the resources of the udev device. |
7d8787b3 KS |
578 | * |
579 | * Returns: a new udev device, or #NULL, in case of an error | |
580 | **/ | |
54cf0b7f | 581 | _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor) |
ba6929f6 | 582 | { |
912541b0 KS |
583 | struct udev_device *udev_device; |
584 | struct msghdr smsg; | |
585 | struct iovec iov; | |
586 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
587 | struct cmsghdr *cmsg; | |
b49d9b50 | 588 | union sockaddr_union snl; |
912541b0 | 589 | struct ucred *cred; |
bf3dd6b1 SL |
590 | union { |
591 | struct udev_monitor_netlink_header nlh; | |
592 | char raw[8192]; | |
593 | } buf; | |
912541b0 KS |
594 | ssize_t buflen; |
595 | ssize_t bufpos; | |
2df959ec | 596 | bool is_initialized = false; |
ba6929f6 | 597 | |
e14bdd88 | 598 | retry: |
912541b0 KS |
599 | if (udev_monitor == NULL) |
600 | return NULL; | |
912541b0 KS |
601 | iov.iov_base = &buf; |
602 | iov.iov_len = sizeof(buf); | |
29804cc1 | 603 | memzero(&smsg, sizeof(struct msghdr)); |
912541b0 KS |
604 | smsg.msg_iov = &iov; |
605 | smsg.msg_iovlen = 1; | |
606 | smsg.msg_control = cred_msg; | |
607 | smsg.msg_controllen = sizeof(cred_msg); | |
f6613dd9 KS |
608 | smsg.msg_name = &snl; |
609 | smsg.msg_namelen = sizeof(snl); | |
912541b0 | 610 | |
a38d9945 | 611 | buflen = recvmsg(udev_monitor->sock, &smsg, 0); |
912541b0 KS |
612 | if (buflen < 0) { |
613 | if (errno != EINTR) | |
ff49bc32 | 614 | log_debug("unable to receive message"); |
912541b0 KS |
615 | return NULL; |
616 | } | |
617 | ||
9c89c1ca | 618 | if (buflen < 32 || (smsg.msg_flags & MSG_TRUNC)) { |
ff49bc32 | 619 | log_debug("invalid message length"); |
912541b0 KS |
620 | return NULL; |
621 | } | |
622 | ||
f6613dd9 KS |
623 | if (snl.nl.nl_groups == 0) { |
624 | /* unicast message, check if we trust the sender */ | |
625 | if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 || | |
626 | snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) { | |
ff49bc32 | 627 | log_debug("unicast netlink message ignored"); |
f6613dd9 KS |
628 | return NULL; |
629 | } | |
630 | } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) { | |
631 | if (snl.nl.nl_pid > 0) { | |
1fa2f38f ZJS |
632 | log_debug("multicast kernel netlink message from PID %"PRIu32" ignored", |
633 | snl.nl.nl_pid); | |
f6613dd9 | 634 | return NULL; |
912541b0 KS |
635 | } |
636 | } | |
637 | ||
638 | cmsg = CMSG_FIRSTHDR(&smsg); | |
639 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
ff49bc32 | 640 | log_debug("no sender credentials received, message ignored"); |
912541b0 KS |
641 | return NULL; |
642 | } | |
643 | ||
644 | cred = (struct ucred *)CMSG_DATA(cmsg); | |
645 | if (cred->uid != 0) { | |
1fa2f38f | 646 | log_debug("sender uid="UID_FMT", message ignored", cred->uid); |
912541b0 KS |
647 | return NULL; |
648 | } | |
649 | ||
bf3dd6b1 | 650 | if (memcmp(buf.raw, "libudev", 8) == 0) { |
912541b0 | 651 | /* udev message needs proper version magic */ |
8e38570e | 652 | if (buf.nlh.magic != htobe32(UDEV_MONITOR_MAGIC)) { |
ff49bc32 | 653 | log_debug("unrecognized message signature (%x != %x)", |
8e38570e | 654 | buf.nlh.magic, htobe32(UDEV_MONITOR_MAGIC)); |
912541b0 KS |
655 | return NULL; |
656 | } | |
bf3dd6b1 | 657 | if (buf.nlh.properties_off+32 > (size_t)buflen) { |
e6ac88dd TG |
658 | log_debug("message smaller than expected (%u > %zd)", |
659 | buf.nlh.properties_off+32, buflen); | |
912541b0 | 660 | return NULL; |
f6613dd9 KS |
661 | } |
662 | ||
bf3dd6b1 | 663 | bufpos = buf.nlh.properties_off; |
f6613dd9 KS |
664 | |
665 | /* devices received from udev are always initialized */ | |
2df959ec | 666 | is_initialized = true; |
912541b0 KS |
667 | } else { |
668 | /* kernel message with header */ | |
bf3dd6b1 | 669 | bufpos = strlen(buf.raw) + 1; |
912541b0 | 670 | if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { |
ff49bc32 | 671 | log_debug("invalid message length"); |
912541b0 KS |
672 | return NULL; |
673 | } | |
674 | ||
675 | /* check message header */ | |
bf3dd6b1 | 676 | if (strstr(buf.raw, "@/") == NULL) { |
ff49bc32 | 677 | log_debug("unrecognized message header"); |
912541b0 KS |
678 | return NULL; |
679 | } | |
680 | } | |
681 | ||
2df959ec | 682 | udev_device = udev_device_new_from_nulstr(udev_monitor->udev, &buf.raw[bufpos], buflen - bufpos); |
e6ac88dd TG |
683 | if (!udev_device) { |
684 | log_debug("could not create device: %m"); | |
912541b0 | 685 | return NULL; |
e6ac88dd | 686 | } |
2df959ec TG |
687 | |
688 | if (is_initialized) | |
689 | udev_device_set_is_initialized(udev_device); | |
912541b0 KS |
690 | |
691 | /* skip device, if it does not pass the current filter */ | |
692 | if (!passes_filter(udev_monitor, udev_device)) { | |
693 | struct pollfd pfd[1]; | |
694 | int rc; | |
695 | ||
696 | udev_device_unref(udev_device); | |
697 | ||
698 | /* if something is queued, get next device */ | |
699 | pfd[0].fd = udev_monitor->sock; | |
700 | pfd[0].events = POLLIN; | |
701 | rc = poll(pfd, 1, 0); | |
702 | if (rc > 0) | |
703 | goto retry; | |
704 | return NULL; | |
705 | } | |
706 | ||
707 | return udev_device; | |
ba6929f6 | 708 | } |
9925ab04 | 709 | |
1e03b754 | 710 | int udev_monitor_send_device(struct udev_monitor *udev_monitor, |
912541b0 | 711 | struct udev_monitor *destination, struct udev_device *udev_device) |
9925ab04 | 712 | { |
81b9fe54 ZJS |
713 | const char *buf, *val; |
714 | ssize_t blen, count; | |
715 | struct udev_monitor_netlink_header nlh = { | |
716 | .prefix = "libudev", | |
8e38570e | 717 | .magic = htobe32(UDEV_MONITOR_MAGIC), |
81b9fe54 ZJS |
718 | .header_size = sizeof nlh, |
719 | }; | |
720 | struct iovec iov[2] = { | |
721 | { .iov_base = &nlh, .iov_len = sizeof nlh }, | |
722 | }; | |
723 | struct msghdr smsg = { | |
724 | .msg_iov = iov, | |
725 | .msg_iovlen = 2, | |
726 | }; | |
2d13da88 KS |
727 | struct udev_list_entry *list_entry; |
728 | uint64_t tag_bloom_bits; | |
729 | ||
912541b0 | 730 | blen = udev_device_get_properties_monitor_buf(udev_device, &buf); |
e6ac88dd TG |
731 | if (blen < 32) { |
732 | log_debug("device buffer is too small to contain a valid device"); | |
912541b0 | 733 | return -EINVAL; |
e6ac88dd | 734 | } |
912541b0 | 735 | |
81b9fe54 | 736 | /* fill in versioned header */ |
2d13da88 | 737 | val = udev_device_get_subsystem(udev_device); |
8e38570e | 738 | nlh.filter_subsystem_hash = htobe32(util_string_hash32(val)); |
81b9fe54 | 739 | |
2d13da88 KS |
740 | val = udev_device_get_devtype(udev_device); |
741 | if (val != NULL) | |
8e38570e | 742 | nlh.filter_devtype_hash = htobe32(util_string_hash32(val)); |
2d13da88 KS |
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) { | |
8e38570e LP |
749 | nlh.filter_tag_bloom_hi = htobe32(tag_bloom_bits >> 32); |
750 | nlh.filter_tag_bloom_lo = htobe32(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 | |
2d13da88 KS |
759 | /* |
760 | * Use custom address for target, or the default one. | |
761 | * | |
762 | * If we send to a multicast group, we will get | |
763 | * ECONNREFUSED, which is expected. | |
764 | */ | |
a4445e88 | 765 | if (destination) |
2d13da88 KS |
766 | smsg.msg_name = &destination->snl; |
767 | else | |
768 | smsg.msg_name = &udev_monitor->snl_destination; | |
769 | smsg.msg_namelen = sizeof(struct sockaddr_nl); | |
770 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
a4445e88 TG |
771 | if (count < 0) { |
772 | if (!destination && errno == ECONNREFUSED) { | |
7800bf71 | 773 | log_debug("passed device to netlink monitor %p", udev_monitor); |
a4445e88 TG |
774 | return 0; |
775 | } else | |
776 | return -errno; | |
777 | } | |
778 | ||
965288c5 | 779 | log_debug("passed %zi byte device to netlink monitor %p", count, udev_monitor); |
2d13da88 | 780 | return count; |
9925ab04 | 781 | } |
e14bdd88 | 782 | |
ce1d6d7f KS |
783 | /** |
784 | * udev_monitor_filter_add_match_subsystem_devtype: | |
785 | * @udev_monitor: the monitor | |
786 | * @subsystem: the subsystem value to match the incoming devices against | |
214a6c79 | 787 | * @devtype: the devtype value to match the incoming devices against |
ce1d6d7f | 788 | * |
50579295 | 789 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
790 | * will usually not be woken up for devices which do not match. |
791 | * | |
ce1d6d7f KS |
792 | * The filter must be installed before the monitor is switched to listening mode. |
793 | * | |
794 | * Returns: 0 on success, otherwise a negative error value. | |
795 | */ | |
54cf0b7f | 796 | _public_ int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype) |
e14bdd88 | 797 | { |
912541b0 KS |
798 | if (udev_monitor == NULL) |
799 | return -EINVAL; | |
800 | if (subsystem == NULL) | |
801 | return -EINVAL; | |
802 | if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL) | |
803 | return -ENOMEM; | |
804 | return 0; | |
e14bdd88 | 805 | } |
08a7a795 | 806 | |
28460195 KS |
807 | /** |
808 | * udev_monitor_filter_add_match_tag: | |
809 | * @udev_monitor: the monitor | |
810 | * @tag: the name of a tag | |
811 | * | |
50579295 | 812 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
813 | * will usually not be woken up for devices which do not match. |
814 | * | |
815 | * The filter must be installed before the monitor is switched to listening mode. | |
816 | * | |
817 | * Returns: 0 on success, otherwise a negative error value. | |
818 | */ | |
54cf0b7f | 819 | _public_ int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag) |
28460195 | 820 | { |
912541b0 KS |
821 | if (udev_monitor == NULL) |
822 | return -EINVAL; | |
823 | if (tag == NULL) | |
824 | return -EINVAL; | |
825 | if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL) | |
826 | return -ENOMEM; | |
827 | return 0; | |
28460195 KS |
828 | } |
829 | ||
ce1d6d7f KS |
830 | /** |
831 | * udev_monitor_filter_remove: | |
832 | * @udev_monitor: monitor | |
833 | * | |
834 | * Remove all filters from monitor. | |
835 | * | |
836 | * Returns: 0 on success, otherwise a negative error value. | |
837 | */ | |
54cf0b7f | 838 | _public_ int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
08a7a795 | 839 | { |
912541b0 | 840 | static struct sock_fprog filter = { 0, NULL }; |
08a7a795 | 841 | |
912541b0 KS |
842 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
843 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
08a7a795 | 844 | } |