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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
88a6477e | 2 | /*** |
88a6477e | 3 | Copyright 2008-2012 Kay Sievers <kay@vrfy.org> |
88a6477e | 4 | ***/ |
ba6929f6 | 5 | |
07630cea LP |
6 | #include <errno.h> |
7 | #include <linux/filter.h> | |
8 | #include <linux/netlink.h> | |
9 | #include <poll.h> | |
10 | #include <stddef.h> | |
ba6929f6 KS |
11 | #include <stdio.h> |
12 | #include <stdlib.h> | |
ba6929f6 | 13 | #include <string.h> |
ba6929f6 | 14 | #include <sys/socket.h> |
07630cea | 15 | #include <unistd.h> |
ba6929f6 | 16 | |
b4bbcaa9 TA |
17 | #include "libudev.h" |
18 | ||
b5efdb8a | 19 | #include "alloc-util.h" |
3ffd4af2 | 20 | #include "fd-util.h" |
0d39fa9c | 21 | #include "fileio.h" |
f97b34a6 | 22 | #include "format-util.h" |
ba6929f6 | 23 | #include "libudev-private.h" |
df32a1ca | 24 | #include "missing.h" |
4e036b7a | 25 | #include "mount-util.h" |
07630cea LP |
26 | #include "socket-util.h" |
27 | #include "string-util.h" | |
ba6929f6 | 28 | |
ce1d6d7f KS |
29 | /** |
30 | * SECTION:libudev-monitor | |
31 | * @short_description: device event source | |
32 | * | |
33 | * Connects to a device event source. | |
34 | */ | |
35 | ||
ce1d6d7f KS |
36 | /** |
37 | * udev_monitor: | |
38 | * | |
50579295 | 39 | * Opaque object handling an event source. |
ce1d6d7f | 40 | */ |
ba6929f6 | 41 | struct udev_monitor { |
912541b0 KS |
42 | struct udev *udev; |
43 | int refcount; | |
44 | int sock; | |
b49d9b50 KS |
45 | union sockaddr_union snl; |
46 | union sockaddr_union snl_trusted_sender; | |
47 | union sockaddr_union snl_destination; | |
912541b0 KS |
48 | socklen_t addrlen; |
49 | struct udev_list filter_subsystem_list; | |
50 | struct udev_list filter_tag_list; | |
51 | bool bound; | |
ba6929f6 KS |
52 | }; |
53 | ||
f2b93744 | 54 | enum udev_monitor_netlink_group { |
912541b0 KS |
55 | UDEV_MONITOR_NONE, |
56 | UDEV_MONITOR_KERNEL, | |
57 | UDEV_MONITOR_UDEV, | |
f2b93744 KS |
58 | }; |
59 | ||
912541b0 | 60 | #define UDEV_MONITOR_MAGIC 0xfeedcafe |
e14bdd88 | 61 | struct udev_monitor_netlink_header { |
912541b0 KS |
62 | /* "libudev" prefix to distinguish libudev and kernel messages */ |
63 | char prefix[8]; | |
64 | /* | |
65 | * magic to protect against daemon <-> library message format mismatch | |
66 | * used in the kernel from socket filter rules; needs to be stored in network order | |
67 | */ | |
68 | unsigned int magic; | |
69 | /* total length of header structure known to the sender */ | |
70 | unsigned int header_size; | |
71 | /* properties string buffer */ | |
72 | unsigned int properties_off; | |
73 | unsigned int properties_len; | |
74 | /* | |
75 | * hashes of primary device properties strings, to let libudev subscribers | |
76 | * use in-kernel socket filters; values need to be stored in network order | |
77 | */ | |
78 | unsigned int filter_subsystem_hash; | |
79 | unsigned int filter_devtype_hash; | |
80 | unsigned int filter_tag_bloom_hi; | |
81 | unsigned int filter_tag_bloom_lo; | |
e14bdd88 KS |
82 | }; |
83 | ||
654c87e0 | 84 | static struct udev_monitor *udev_monitor_new(struct udev *udev) { |
912541b0 KS |
85 | struct udev_monitor *udev_monitor; |
86 | ||
955d98c9 | 87 | udev_monitor = new0(struct udev_monitor, 1); |
309f631d LP |
88 | if (udev_monitor == NULL) { |
89 | errno = ENOMEM; | |
912541b0 | 90 | return NULL; |
309f631d | 91 | } |
912541b0 KS |
92 | udev_monitor->refcount = 1; |
93 | udev_monitor->udev = udev; | |
94 | udev_list_init(udev, &udev_monitor->filter_subsystem_list, false); | |
95 | udev_list_init(udev, &udev_monitor->filter_tag_list, true); | |
96 | return udev_monitor; | |
e14bdd88 KS |
97 | } |
98 | ||
df32a1ca KS |
99 | /* we consider udev running when /dev is on devtmpfs */ |
100 | static bool udev_has_devtmpfs(struct udev *udev) { | |
21749924 | 101 | |
df32a1ca KS |
102 | _cleanup_fclose_ FILE *f = NULL; |
103 | char line[LINE_MAX], *e; | |
654c87e0 | 104 | int mount_id, r; |
df32a1ca | 105 | |
654c87e0 | 106 | r = path_get_mnt_id("/dev", &mount_id); |
e6c47472 | 107 | if (r < 0) { |
654c87e0 LP |
108 | if (r != -EOPNOTSUPP) |
109 | log_debug_errno(r, "name_to_handle_at on /dev: %m"); | |
110 | ||
df32a1ca | 111 | return false; |
e6c47472 | 112 | } |
df32a1ca | 113 | |
df32a1ca KS |
114 | f = fopen("/proc/self/mountinfo", "re"); |
115 | if (!f) | |
116 | return false; | |
117 | ||
118 | FOREACH_LINE(line, f, return false) { | |
df32a1ca KS |
119 | int mid; |
120 | ||
121 | if (sscanf(line, "%i", &mid) != 1) | |
122 | continue; | |
123 | ||
124 | if (mid != mount_id) | |
125 | continue; | |
126 | ||
127 | e = strstr(line, " - "); | |
128 | if (!e) | |
129 | continue; | |
130 | ||
131 | /* accept any name that starts with the currently expected type */ | |
132 | if (startswith(e + 3, "devtmpfs")) | |
133 | return true; | |
134 | } | |
135 | ||
136 | return false; | |
137 | } | |
138 | ||
44daf75d TG |
139 | static void monitor_set_nl_address(struct udev_monitor *udev_monitor) { |
140 | union sockaddr_union snl; | |
141 | socklen_t addrlen; | |
142 | int r; | |
143 | ||
144 | assert(udev_monitor); | |
145 | ||
146 | /* get the address the kernel has assigned us | |
147 | * it is usually, but not necessarily the pid | |
148 | */ | |
149 | addrlen = sizeof(struct sockaddr_nl); | |
150 | r = getsockname(udev_monitor->sock, &snl.sa, &addrlen); | |
151 | if (r >= 0) | |
152 | udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid; | |
153 | } | |
154 | ||
654c87e0 | 155 | struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) { |
912541b0 KS |
156 | struct udev_monitor *udev_monitor; |
157 | unsigned int group; | |
158 | ||
309f631d LP |
159 | if (udev == NULL) { |
160 | errno = EINVAL; | |
912541b0 | 161 | return NULL; |
309f631d | 162 | } |
912541b0 KS |
163 | |
164 | if (name == NULL) | |
165 | group = UDEV_MONITOR_NONE; | |
e8a3b2dc KS |
166 | else if (streq(name, "udev")) { |
167 | /* | |
168 | * We do not support subscribing to uevents if no instance of | |
169 | * udev is running. Uevents would otherwise broadcast the | |
170 | * processing data of the host into containers, which is not | |
171 | * desired. | |
172 | * | |
173 | * Containers will currently not get any udev uevents, until | |
174 | * a supporting infrastructure is available. | |
175 | * | |
176 | * We do not set a netlink multicast group here, so the socket | |
177 | * will not receive any messages. | |
178 | */ | |
9ea28c55 | 179 | if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) { |
ff49bc32 | 180 | log_debug("the udev service seems not to be active, disable the monitor"); |
e8a3b2dc KS |
181 | group = UDEV_MONITOR_NONE; |
182 | } else | |
183 | group = UDEV_MONITOR_UDEV; | |
184 | } else if (streq(name, "kernel")) | |
912541b0 | 185 | group = UDEV_MONITOR_KERNEL; |
309f631d LP |
186 | else { |
187 | errno = EINVAL; | |
912541b0 | 188 | return NULL; |
309f631d | 189 | } |
912541b0 KS |
190 | |
191 | udev_monitor = udev_monitor_new(udev); | |
192 | if (udev_monitor == NULL) | |
193 | return NULL; | |
194 | ||
195 | if (fd < 0) { | |
196 | udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); | |
44daf75d | 197 | if (udev_monitor->sock < 0) { |
56f64d95 | 198 | log_debug_errno(errno, "error getting socket: %m"); |
6b430fdb | 199 | return mfree(udev_monitor); |
912541b0 KS |
200 | } |
201 | } else { | |
202 | udev_monitor->bound = true; | |
203 | udev_monitor->sock = fd; | |
44daf75d | 204 | monitor_set_nl_address(udev_monitor); |
912541b0 KS |
205 | } |
206 | ||
b49d9b50 KS |
207 | udev_monitor->snl.nl.nl_family = AF_NETLINK; |
208 | udev_monitor->snl.nl.nl_groups = group; | |
912541b0 KS |
209 | |
210 | /* default destination for sending */ | |
b49d9b50 KS |
211 | udev_monitor->snl_destination.nl.nl_family = AF_NETLINK; |
212 | udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV; | |
912541b0 | 213 | |
912541b0 | 214 | return udev_monitor; |
1c7047ea KS |
215 | } |
216 | ||
7459bcdc KS |
217 | /** |
218 | * udev_monitor_new_from_netlink: | |
219 | * @udev: udev library context | |
220 | * @name: name of event source | |
221 | * | |
222 | * Create new udev monitor and connect to a specified event | |
223 | * source. Valid sources identifiers are "udev" and "kernel". | |
224 | * | |
225 | * Applications should usually not connect directly to the | |
226 | * "kernel" events, because the devices might not be useable | |
227 | * at that time, before udev has configured them, and created | |
50579295 KS |
228 | * device nodes. Accessing devices at the same time as udev, |
229 | * might result in unpredictable behavior. The "udev" events | |
230 | * are sent out after udev has finished its event processing, | |
231 | * all rules have been processed, and needed device nodes are | |
232 | * created. | |
7459bcdc KS |
233 | * |
234 | * The initial refcount is 1, and needs to be decremented to | |
235 | * release the resources of the udev monitor. | |
236 | * | |
237 | * Returns: a new udev monitor, or #NULL, in case of an error | |
238 | **/ | |
654c87e0 | 239 | _public_ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) { |
912541b0 | 240 | return udev_monitor_new_from_netlink_fd(udev, name, -1); |
7459bcdc KS |
241 | } |
242 | ||
e14bdd88 | 243 | static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i, |
912541b0 | 244 | unsigned short code, unsigned int data) |
e14bdd88 | 245 | { |
912541b0 | 246 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 247 | |
912541b0 KS |
248 | ins->code = code; |
249 | ins->k = data; | |
250 | (*i)++; | |
e14bdd88 KS |
251 | } |
252 | ||
253 | static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i, | |
912541b0 KS |
254 | unsigned short code, unsigned int data, |
255 | unsigned short jt, unsigned short jf) | |
e14bdd88 | 256 | { |
912541b0 | 257 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 258 | |
912541b0 KS |
259 | ins->code = code; |
260 | ins->jt = jt; | |
261 | ins->jf = jf; | |
262 | ins->k = data; | |
263 | (*i)++; | |
e14bdd88 KS |
264 | } |
265 | ||
ce1d6d7f KS |
266 | /** |
267 | * udev_monitor_filter_update: | |
268 | * @udev_monitor: monitor | |
269 | * | |
50579295 KS |
270 | * Update the installed socket filter. This is only needed, |
271 | * if the filter was removed or changed. | |
ce1d6d7f KS |
272 | * |
273 | * Returns: 0 on success, otherwise a negative error value. | |
274 | */ | |
54cf0b7f | 275 | _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor) |
e14bdd88 | 276 | { |
912541b0 KS |
277 | struct sock_filter ins[512]; |
278 | struct sock_fprog filter; | |
279 | unsigned int i; | |
280 | struct udev_list_entry *list_entry; | |
281 | int err; | |
282 | ||
283 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL && | |
284 | udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) | |
285 | return 0; | |
286 | ||
29804cc1 | 287 | memzero(ins, sizeof(ins)); |
912541b0 KS |
288 | i = 0; |
289 | ||
290 | /* load magic in A */ | |
291 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic)); | |
292 | /* jump if magic matches */ | |
293 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); | |
294 | /* wrong magic, pass packet */ | |
295 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
296 | ||
297 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) { | |
298 | int tag_matches; | |
299 | ||
300 | /* count tag matches, to calculate end of tag match block */ | |
301 | tag_matches = 0; | |
302 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) | |
303 | tag_matches++; | |
304 | ||
305 | /* add all tags matches */ | |
306 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
307 | uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
308 | uint32_t tag_bloom_hi = tag_bloom_bits >> 32; | |
309 | uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; | |
310 | ||
311 | /* load device bloom bits in A */ | |
312 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi)); | |
313 | /* clear bits (tag bits & bloom bits) */ | |
314 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); | |
315 | /* jump to next tag if it does not match */ | |
316 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); | |
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_lo)); | |
320 | /* clear bits (tag bits & bloom bits) */ | |
321 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); | |
322 | /* jump behind end of tag match block if tag matches */ | |
323 | tag_matches--; | |
324 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); | |
325 | } | |
326 | ||
327 | /* nothing matched, drop packet */ | |
328 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
329 | } | |
330 | ||
331 | /* add all subsystem matches */ | |
332 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) { | |
333 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
334 | unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry)); | |
335 | ||
336 | /* load device subsystem value in A */ | |
337 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash)); | |
338 | if (udev_list_entry_get_value(list_entry) == NULL) { | |
339 | /* jump if subsystem does not match */ | |
340 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
341 | } else { | |
342 | /* jump if subsystem does not match */ | |
343 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); | |
344 | ||
345 | /* load device devtype value in A */ | |
346 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash)); | |
347 | /* jump if value does not match */ | |
348 | hash = util_string_hash32(udev_list_entry_get_value(list_entry)); | |
349 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
350 | } | |
351 | ||
352 | /* matched, pass packet */ | |
353 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
354 | ||
8fef0ff2 | 355 | if (i+1 >= ELEMENTSOF(ins)) |
994e0234 | 356 | return -E2BIG; |
912541b0 KS |
357 | } |
358 | ||
359 | /* nothing matched, drop packet */ | |
360 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
361 | } | |
362 | ||
363 | /* matched, pass packet */ | |
364 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
365 | ||
366 | /* install filter */ | |
29804cc1 | 367 | memzero(&filter, sizeof(filter)); |
912541b0 KS |
368 | filter.len = i; |
369 | filter.filter = ins; | |
370 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
994e0234 | 371 | return err < 0 ? -errno : 0; |
e14bdd88 KS |
372 | } |
373 | ||
1e03b754 KS |
374 | int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
375 | { | |
b49d9b50 | 376 | udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid; |
912541b0 | 377 | return 0; |
1e03b754 | 378 | } |
44daf75d | 379 | |
ce1d6d7f KS |
380 | /** |
381 | * udev_monitor_enable_receiving: | |
382 | * @udev_monitor: the monitor which should receive events | |
383 | * | |
384 | * Binds the @udev_monitor socket to the event source. | |
385 | * | |
386 | * Returns: 0 on success, otherwise a negative error value. | |
387 | */ | |
54cf0b7f | 388 | _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
d59f11e1 | 389 | { |
912541b0 KS |
390 | int err = 0; |
391 | const int on = 1; | |
392 | ||
2d13da88 KS |
393 | udev_monitor_filter_update(udev_monitor); |
394 | ||
395 | if (!udev_monitor->bound) { | |
396 | err = bind(udev_monitor->sock, | |
b49d9b50 | 397 | &udev_monitor->snl.sa, sizeof(struct sockaddr_nl)); |
2d13da88 KS |
398 | if (err == 0) |
399 | udev_monitor->bound = true; | |
912541b0 KS |
400 | } |
401 | ||
44daf75d TG |
402 | if (err >= 0) |
403 | monitor_set_nl_address(udev_monitor); | |
e1427b13 MS |
404 | else |
405 | return log_debug_errno(errno, "bind failed: %m"); | |
912541b0 KS |
406 | |
407 | /* enable receiving of sender credentials */ | |
9dedfe7f TG |
408 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); |
409 | if (err < 0) | |
56f64d95 | 410 | log_debug_errno(errno, "setting SO_PASSCRED failed: %m"); |
9dedfe7f | 411 | |
912541b0 | 412 | return 0; |
ba6929f6 KS |
413 | } |
414 | ||
f712894d KS |
415 | /** |
416 | * udev_monitor_set_receive_buffer_size: | |
417 | * @udev_monitor: the monitor which should receive events | |
418 | * @size: the size in bytes | |
419 | * | |
420 | * Set the size of the kernel socket buffer. This call needs the | |
421 | * appropriate privileges to succeed. | |
422 | * | |
423 | * Returns: 0 on success, otherwise -1 on error. | |
424 | */ | |
54cf0b7f | 425 | _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
cb25a958 | 426 | { |
912541b0 | 427 | if (udev_monitor == NULL) |
994e0234 | 428 | return -EINVAL; |
309f631d LP |
429 | if (setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)) < 0) |
430 | return -errno; | |
431 | ||
432 | return 0; | |
cb25a958 KS |
433 | } |
434 | ||
1e03b754 KS |
435 | int udev_monitor_disconnect(struct udev_monitor *udev_monitor) |
436 | { | |
912541b0 | 437 | int err; |
1e03b754 | 438 | |
912541b0 KS |
439 | err = close(udev_monitor->sock); |
440 | udev_monitor->sock = -1; | |
994e0234 | 441 | return err < 0 ? -errno : 0; |
1e03b754 KS |
442 | } |
443 | ||
7d8787b3 KS |
444 | /** |
445 | * udev_monitor_ref: | |
446 | * @udev_monitor: udev monitor | |
447 | * | |
448 | * Take a reference of a udev monitor. | |
449 | * | |
450 | * Returns: the passed udev monitor | |
451 | **/ | |
54cf0b7f | 452 | _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor) |
ba6929f6 | 453 | { |
912541b0 KS |
454 | if (udev_monitor == NULL) |
455 | return NULL; | |
456 | udev_monitor->refcount++; | |
457 | return udev_monitor; | |
ba6929f6 KS |
458 | } |
459 | ||
7d8787b3 KS |
460 | /** |
461 | * udev_monitor_unref: | |
462 | * @udev_monitor: udev monitor | |
463 | * | |
ff109b8d | 464 | * Drop a reference of a udev monitor. If the refcount reaches zero, |
be7de409 | 465 | * the bound socket will be closed, and the resources of the monitor |
7d8787b3 KS |
466 | * will be released. |
467 | * | |
725d7e6c | 468 | * Returns: #NULL |
7d8787b3 | 469 | **/ |
20bbd54f | 470 | _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor) |
ba6929f6 | 471 | { |
912541b0 | 472 | if (udev_monitor == NULL) |
20bbd54f | 473 | return NULL; |
912541b0 KS |
474 | udev_monitor->refcount--; |
475 | if (udev_monitor->refcount > 0) | |
725d7e6c | 476 | return NULL; |
912541b0 KS |
477 | if (udev_monitor->sock >= 0) |
478 | close(udev_monitor->sock); | |
479 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); | |
480 | udev_list_cleanup(&udev_monitor->filter_tag_list); | |
5fecf46d | 481 | return mfree(udev_monitor); |
ba6929f6 KS |
482 | } |
483 | ||
7d8787b3 KS |
484 | /** |
485 | * udev_monitor_get_udev: | |
486 | * @udev_monitor: udev monitor | |
487 | * | |
b98fd840 | 488 | * Retrieve the udev library context the monitor was created with. |
7d8787b3 KS |
489 | * |
490 | * Returns: the udev library context | |
491 | **/ | |
54cf0b7f | 492 | _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor) |
ba6929f6 | 493 | { |
912541b0 KS |
494 | if (udev_monitor == NULL) |
495 | return NULL; | |
496 | return udev_monitor->udev; | |
ba6929f6 KS |
497 | } |
498 | ||
7d8787b3 KS |
499 | /** |
500 | * udev_monitor_get_fd: | |
501 | * @udev_monitor: udev monitor | |
502 | * | |
503 | * Retrieve the socket file descriptor associated with the monitor. | |
504 | * | |
505 | * Returns: the socket file descriptor | |
506 | **/ | |
54cf0b7f | 507 | _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
ba6929f6 | 508 | { |
912541b0 | 509 | if (udev_monitor == NULL) |
994e0234 | 510 | return -EINVAL; |
912541b0 | 511 | return udev_monitor->sock; |
ba6929f6 KS |
512 | } |
513 | ||
e14bdd88 KS |
514 | static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device) |
515 | { | |
912541b0 KS |
516 | struct udev_list_entry *list_entry; |
517 | ||
518 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL) | |
519 | goto tag; | |
520 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
521 | const char *subsys = udev_list_entry_get_name(list_entry); | |
522 | const char *dsubsys = udev_device_get_subsystem(udev_device); | |
523 | const char *devtype; | |
524 | const char *ddevtype; | |
525 | ||
090be865 | 526 | if (!streq(dsubsys, subsys)) |
912541b0 KS |
527 | continue; |
528 | ||
529 | devtype = udev_list_entry_get_value(list_entry); | |
530 | if (devtype == NULL) | |
531 | goto tag; | |
532 | ddevtype = udev_device_get_devtype(udev_device); | |
533 | if (ddevtype == NULL) | |
534 | continue; | |
090be865 | 535 | if (streq(ddevtype, devtype)) |
912541b0 KS |
536 | goto tag; |
537 | } | |
538 | return 0; | |
28460195 KS |
539 | |
540 | tag: | |
912541b0 KS |
541 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) |
542 | return 1; | |
543 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
544 | const char *tag = udev_list_entry_get_name(list_entry); | |
545 | ||
546 | if (udev_device_has_tag(udev_device, tag)) | |
547 | return 1; | |
548 | } | |
549 | return 0; | |
e14bdd88 KS |
550 | } |
551 | ||
7d8787b3 | 552 | /** |
d59f11e1 | 553 | * udev_monitor_receive_device: |
7d8787b3 KS |
554 | * @udev_monitor: udev monitor |
555 | * | |
d59f11e1 | 556 | * Receive data from the udev monitor socket, allocate a new udev |
b98fd840 | 557 | * device, fill in the received data, and return the device. |
7d8787b3 | 558 | * |
50579295 | 559 | * Only socket connections with uid=0 are accepted. |
7d8787b3 | 560 | * |
b30b4260 KS |
561 | * The monitor socket is by default set to NONBLOCK. A variant of poll() on |
562 | * the file descriptor returned by udev_monitor_get_fd() should to be used to | |
563 | * wake up when new devices arrive, or alternatively the file descriptor | |
564 | * switched into blocking mode. | |
565 | * | |
7d8787b3 | 566 | * The initial refcount is 1, and needs to be decremented to |
be7de409 | 567 | * release the resources of the udev device. |
7d8787b3 KS |
568 | * |
569 | * Returns: a new udev device, or #NULL, in case of an error | |
570 | **/ | |
54cf0b7f | 571 | _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor) |
ba6929f6 | 572 | { |
912541b0 KS |
573 | struct udev_device *udev_device; |
574 | struct msghdr smsg; | |
575 | struct iovec iov; | |
576 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
577 | struct cmsghdr *cmsg; | |
b49d9b50 | 578 | union sockaddr_union snl; |
912541b0 | 579 | struct ucred *cred; |
bf3dd6b1 SL |
580 | union { |
581 | struct udev_monitor_netlink_header nlh; | |
582 | char raw[8192]; | |
583 | } buf; | |
912541b0 KS |
584 | ssize_t buflen; |
585 | ssize_t bufpos; | |
2df959ec | 586 | bool is_initialized = false; |
ba6929f6 | 587 | |
e14bdd88 | 588 | retry: |
309f631d LP |
589 | if (udev_monitor == NULL) { |
590 | errno = EINVAL; | |
912541b0 | 591 | return NULL; |
309f631d | 592 | } |
912541b0 KS |
593 | iov.iov_base = &buf; |
594 | iov.iov_len = sizeof(buf); | |
29804cc1 | 595 | memzero(&smsg, sizeof(struct msghdr)); |
912541b0 KS |
596 | smsg.msg_iov = &iov; |
597 | smsg.msg_iovlen = 1; | |
598 | smsg.msg_control = cred_msg; | |
599 | smsg.msg_controllen = sizeof(cred_msg); | |
f6613dd9 KS |
600 | smsg.msg_name = &snl; |
601 | smsg.msg_namelen = sizeof(snl); | |
912541b0 | 602 | |
a38d9945 | 603 | buflen = recvmsg(udev_monitor->sock, &smsg, 0); |
912541b0 KS |
604 | if (buflen < 0) { |
605 | if (errno != EINTR) | |
ff49bc32 | 606 | log_debug("unable to receive message"); |
912541b0 KS |
607 | return NULL; |
608 | } | |
609 | ||
9c89c1ca | 610 | if (buflen < 32 || (smsg.msg_flags & MSG_TRUNC)) { |
ff49bc32 | 611 | log_debug("invalid message length"); |
309f631d | 612 | errno = EINVAL; |
912541b0 KS |
613 | return NULL; |
614 | } | |
615 | ||
f6613dd9 KS |
616 | if (snl.nl.nl_groups == 0) { |
617 | /* unicast message, check if we trust the sender */ | |
618 | if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 || | |
619 | snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) { | |
ff49bc32 | 620 | log_debug("unicast netlink message ignored"); |
309f631d | 621 | errno = EAGAIN; |
f6613dd9 KS |
622 | return NULL; |
623 | } | |
624 | } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) { | |
625 | if (snl.nl.nl_pid > 0) { | |
1fa2f38f ZJS |
626 | log_debug("multicast kernel netlink message from PID %"PRIu32" ignored", |
627 | snl.nl.nl_pid); | |
309f631d | 628 | errno = EAGAIN; |
f6613dd9 | 629 | return NULL; |
912541b0 KS |
630 | } |
631 | } | |
632 | ||
633 | cmsg = CMSG_FIRSTHDR(&smsg); | |
634 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
ff49bc32 | 635 | log_debug("no sender credentials received, message ignored"); |
309f631d | 636 | errno = EAGAIN; |
912541b0 KS |
637 | return NULL; |
638 | } | |
639 | ||
640 | cred = (struct ucred *)CMSG_DATA(cmsg); | |
641 | if (cred->uid != 0) { | |
1fa2f38f | 642 | log_debug("sender uid="UID_FMT", message ignored", cred->uid); |
309f631d | 643 | errno = EAGAIN; |
912541b0 KS |
644 | return NULL; |
645 | } | |
646 | ||
bf3dd6b1 | 647 | if (memcmp(buf.raw, "libudev", 8) == 0) { |
912541b0 | 648 | /* udev message needs proper version magic */ |
8e38570e | 649 | if (buf.nlh.magic != htobe32(UDEV_MONITOR_MAGIC)) { |
ff49bc32 | 650 | log_debug("unrecognized message signature (%x != %x)", |
8e38570e | 651 | buf.nlh.magic, htobe32(UDEV_MONITOR_MAGIC)); |
309f631d | 652 | errno = EAGAIN; |
912541b0 KS |
653 | return NULL; |
654 | } | |
bf3dd6b1 | 655 | if (buf.nlh.properties_off+32 > (size_t)buflen) { |
e6ac88dd TG |
656 | log_debug("message smaller than expected (%u > %zd)", |
657 | buf.nlh.properties_off+32, buflen); | |
309f631d | 658 | errno = EAGAIN; |
912541b0 | 659 | return NULL; |
f6613dd9 KS |
660 | } |
661 | ||
bf3dd6b1 | 662 | bufpos = buf.nlh.properties_off; |
f6613dd9 KS |
663 | |
664 | /* devices received from udev are always initialized */ | |
2df959ec | 665 | is_initialized = true; |
912541b0 KS |
666 | } else { |
667 | /* kernel message with header */ | |
bf3dd6b1 | 668 | bufpos = strlen(buf.raw) + 1; |
912541b0 | 669 | if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { |
ff49bc32 | 670 | log_debug("invalid message length"); |
309f631d | 671 | errno = EAGAIN; |
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"); |
309f631d | 678 | errno = EAGAIN; |
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 | 684 | if (!udev_device) { |
25f027c5 | 685 | log_debug_errno(errno, "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; | |
309f631d LP |
705 | |
706 | errno = EAGAIN; | |
912541b0 KS |
707 | return NULL; |
708 | } | |
709 | ||
710 | return udev_device; | |
ba6929f6 | 711 | } |
9925ab04 | 712 | |
1e03b754 | 713 | int udev_monitor_send_device(struct udev_monitor *udev_monitor, |
912541b0 | 714 | struct udev_monitor *destination, struct udev_device *udev_device) |
9925ab04 | 715 | { |
81b9fe54 ZJS |
716 | const char *buf, *val; |
717 | ssize_t blen, count; | |
718 | struct udev_monitor_netlink_header nlh = { | |
719 | .prefix = "libudev", | |
8e38570e | 720 | .magic = htobe32(UDEV_MONITOR_MAGIC), |
81b9fe54 ZJS |
721 | .header_size = sizeof nlh, |
722 | }; | |
723 | struct iovec iov[2] = { | |
724 | { .iov_base = &nlh, .iov_len = sizeof nlh }, | |
725 | }; | |
726 | struct msghdr smsg = { | |
727 | .msg_iov = iov, | |
728 | .msg_iovlen = 2, | |
729 | }; | |
2d13da88 KS |
730 | struct udev_list_entry *list_entry; |
731 | uint64_t tag_bloom_bits; | |
732 | ||
912541b0 | 733 | blen = udev_device_get_properties_monitor_buf(udev_device, &buf); |
e6ac88dd TG |
734 | if (blen < 32) { |
735 | log_debug("device buffer is too small to contain a valid device"); | |
912541b0 | 736 | return -EINVAL; |
e6ac88dd | 737 | } |
912541b0 | 738 | |
81b9fe54 | 739 | /* fill in versioned header */ |
2d13da88 | 740 | val = udev_device_get_subsystem(udev_device); |
8e38570e | 741 | nlh.filter_subsystem_hash = htobe32(util_string_hash32(val)); |
81b9fe54 | 742 | |
2d13da88 KS |
743 | val = udev_device_get_devtype(udev_device); |
744 | if (val != NULL) | |
8e38570e | 745 | nlh.filter_devtype_hash = htobe32(util_string_hash32(val)); |
2d13da88 KS |
746 | |
747 | /* add tag bloom filter */ | |
748 | tag_bloom_bits = 0; | |
749 | udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device)) | |
750 | tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
751 | if (tag_bloom_bits > 0) { | |
8e38570e LP |
752 | nlh.filter_tag_bloom_hi = htobe32(tag_bloom_bits >> 32); |
753 | nlh.filter_tag_bloom_lo = htobe32(tag_bloom_bits & 0xffffffff); | |
912541b0 KS |
754 | } |
755 | ||
2d13da88 KS |
756 | /* add properties list */ |
757 | nlh.properties_off = iov[0].iov_len; | |
758 | nlh.properties_len = blen; | |
759 | iov[1].iov_base = (char *)buf; | |
760 | iov[1].iov_len = blen; | |
912541b0 | 761 | |
2d13da88 KS |
762 | /* |
763 | * Use custom address for target, or the default one. | |
764 | * | |
765 | * If we send to a multicast group, we will get | |
766 | * ECONNREFUSED, which is expected. | |
767 | */ | |
a4445e88 | 768 | if (destination) |
2d13da88 KS |
769 | smsg.msg_name = &destination->snl; |
770 | else | |
771 | smsg.msg_name = &udev_monitor->snl_destination; | |
772 | smsg.msg_namelen = sizeof(struct sockaddr_nl); | |
773 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
a4445e88 TG |
774 | if (count < 0) { |
775 | if (!destination && errno == ECONNREFUSED) { | |
7800bf71 | 776 | log_debug("passed device to netlink monitor %p", udev_monitor); |
a4445e88 TG |
777 | return 0; |
778 | } else | |
779 | return -errno; | |
780 | } | |
781 | ||
965288c5 | 782 | log_debug("passed %zi byte device to netlink monitor %p", count, udev_monitor); |
2d13da88 | 783 | return count; |
9925ab04 | 784 | } |
e14bdd88 | 785 | |
ce1d6d7f KS |
786 | /** |
787 | * udev_monitor_filter_add_match_subsystem_devtype: | |
788 | * @udev_monitor: the monitor | |
789 | * @subsystem: the subsystem value to match the incoming devices against | |
214a6c79 | 790 | * @devtype: the devtype value to match the incoming devices against |
ce1d6d7f | 791 | * |
50579295 | 792 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
793 | * will usually not be woken up for devices which do not match. |
794 | * | |
ce1d6d7f KS |
795 | * The filter must be installed before the monitor is switched to listening mode. |
796 | * | |
797 | * Returns: 0 on success, otherwise a negative error value. | |
798 | */ | |
54cf0b7f | 799 | _public_ int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype) |
e14bdd88 | 800 | { |
912541b0 KS |
801 | if (udev_monitor == NULL) |
802 | return -EINVAL; | |
803 | if (subsystem == NULL) | |
804 | return -EINVAL; | |
805 | if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL) | |
806 | return -ENOMEM; | |
807 | return 0; | |
e14bdd88 | 808 | } |
08a7a795 | 809 | |
28460195 KS |
810 | /** |
811 | * udev_monitor_filter_add_match_tag: | |
812 | * @udev_monitor: the monitor | |
813 | * @tag: the name of a tag | |
814 | * | |
50579295 | 815 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
816 | * will usually not be woken up for devices which do not match. |
817 | * | |
818 | * The filter must be installed before the monitor is switched to listening mode. | |
819 | * | |
820 | * Returns: 0 on success, otherwise a negative error value. | |
821 | */ | |
54cf0b7f | 822 | _public_ int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag) |
28460195 | 823 | { |
912541b0 KS |
824 | if (udev_monitor == NULL) |
825 | return -EINVAL; | |
826 | if (tag == NULL) | |
827 | return -EINVAL; | |
828 | if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL) | |
829 | return -ENOMEM; | |
830 | return 0; | |
28460195 KS |
831 | } |
832 | ||
ce1d6d7f KS |
833 | /** |
834 | * udev_monitor_filter_remove: | |
835 | * @udev_monitor: monitor | |
836 | * | |
837 | * Remove all filters from monitor. | |
838 | * | |
839 | * Returns: 0 on success, otherwise a negative error value. | |
840 | */ | |
54cf0b7f | 841 | _public_ int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
08a7a795 | 842 | { |
309f631d | 843 | static const struct sock_fprog filter = { 0, NULL }; |
08a7a795 | 844 | |
912541b0 | 845 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
309f631d LP |
846 | if (setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) < 0) |
847 | return -errno; | |
848 | ||
849 | return 0; | |
08a7a795 | 850 | } |