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Commit | Line | Data |
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ba6929f6 KS |
1 | /* |
2 | * libudev - interface to udev device information | |
3 | * | |
28460195 | 4 | * Copyright (C) 2008-2010 Kay Sievers <kay.sievers@vrfy.org> |
ba6929f6 | 5 | * |
4061ab9f KS |
6 | * This library is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
ba6929f6 KS |
10 | */ |
11 | ||
ba6929f6 KS |
12 | #include <stdio.h> |
13 | #include <stdlib.h> | |
14 | #include <stddef.h> | |
15 | #include <unistd.h> | |
16 | #include <errno.h> | |
17 | #include <string.h> | |
18 | #include <dirent.h> | |
e14bdd88 | 19 | #include <sys/poll.h> |
ba6929f6 KS |
20 | #include <sys/stat.h> |
21 | #include <sys/socket.h> | |
22 | #include <sys/un.h> | |
e14bdd88 | 23 | #include <arpa/inet.h> |
1c7047ea | 24 | #include <linux/netlink.h> |
e14bdd88 | 25 | #include <linux/filter.h> |
ba6929f6 KS |
26 | |
27 | #include "libudev.h" | |
28 | #include "libudev-private.h" | |
ba6929f6 | 29 | |
ce1d6d7f KS |
30 | /** |
31 | * SECTION:libudev-monitor | |
32 | * @short_description: device event source | |
33 | * | |
34 | * Connects to a device event source. | |
35 | */ | |
36 | ||
ce1d6d7f KS |
37 | /** |
38 | * udev_monitor: | |
39 | * | |
50579295 | 40 | * Opaque object handling an event source. |
ce1d6d7f | 41 | */ |
ba6929f6 | 42 | struct udev_monitor { |
912541b0 KS |
43 | struct udev *udev; |
44 | int refcount; | |
45 | int sock; | |
46 | struct sockaddr_nl snl; | |
47 | struct sockaddr_nl snl_trusted_sender; | |
48 | struct sockaddr_nl snl_destination; | |
49 | struct sockaddr_un sun; | |
50 | socklen_t addrlen; | |
51 | struct udev_list filter_subsystem_list; | |
52 | struct udev_list filter_tag_list; | |
53 | bool bound; | |
ba6929f6 KS |
54 | }; |
55 | ||
f2b93744 | 56 | enum udev_monitor_netlink_group { |
912541b0 KS |
57 | UDEV_MONITOR_NONE, |
58 | UDEV_MONITOR_KERNEL, | |
59 | UDEV_MONITOR_UDEV, | |
f2b93744 KS |
60 | }; |
61 | ||
912541b0 | 62 | #define UDEV_MONITOR_MAGIC 0xfeedcafe |
e14bdd88 | 63 | struct udev_monitor_netlink_header { |
912541b0 KS |
64 | /* "libudev" prefix to distinguish libudev and kernel messages */ |
65 | char prefix[8]; | |
66 | /* | |
67 | * magic to protect against daemon <-> library message format mismatch | |
68 | * used in the kernel from socket filter rules; needs to be stored in network order | |
69 | */ | |
70 | unsigned int magic; | |
71 | /* total length of header structure known to the sender */ | |
72 | unsigned int header_size; | |
73 | /* properties string buffer */ | |
74 | unsigned int properties_off; | |
75 | unsigned int properties_len; | |
76 | /* | |
77 | * hashes of primary device properties strings, to let libudev subscribers | |
78 | * use in-kernel socket filters; values need to be stored in network order | |
79 | */ | |
80 | unsigned int filter_subsystem_hash; | |
81 | unsigned int filter_devtype_hash; | |
82 | unsigned int filter_tag_bloom_hi; | |
83 | unsigned int filter_tag_bloom_lo; | |
e14bdd88 KS |
84 | }; |
85 | ||
86 | static struct udev_monitor *udev_monitor_new(struct udev *udev) | |
87 | { | |
912541b0 KS |
88 | struct udev_monitor *udev_monitor; |
89 | ||
90 | udev_monitor = calloc(1, sizeof(struct udev_monitor)); | |
91 | if (udev_monitor == NULL) | |
92 | return NULL; | |
93 | udev_monitor->refcount = 1; | |
94 | udev_monitor->udev = udev; | |
95 | udev_list_init(udev, &udev_monitor->filter_subsystem_list, false); | |
96 | udev_list_init(udev, &udev_monitor->filter_tag_list, true); | |
97 | return udev_monitor; | |
e14bdd88 KS |
98 | } |
99 | ||
7d8787b3 KS |
100 | /** |
101 | * udev_monitor_new_from_socket: | |
102 | * @udev: udev library context | |
103 | * @socket_path: unix socket path | |
104 | * | |
50579295 KS |
105 | * This function should not be used in any new application. The |
106 | * kernel's netlink socket multiplexes messages to all interested | |
107 | * clients. Creating custom sockets from udev to applications | |
108 | * should be avoided. | |
109 | * | |
110 | * Create a new udev monitor and connect to a specified socket. The | |
ff109b8d KS |
111 | * path to a socket either points to an existing socket file, or if |
112 | * the socket path starts with a '@' character, an abstract namespace | |
7d8787b3 KS |
113 | * socket will be used. |
114 | * | |
ff109b8d KS |
115 | * A socket file will not be created. If it does not already exist, |
116 | * it will fall-back and connect to an abstract namespace socket with | |
117 | * the given path. The permissions adjustment of a socket file, as | |
118 | * well as the later cleanup, needs to be done by the caller. | |
119 | * | |
7d8787b3 | 120 | * The initial refcount is 1, and needs to be decremented to |
be7de409 | 121 | * release the resources of the udev monitor. |
7d8787b3 KS |
122 | * |
123 | * Returns: a new udev monitor, or #NULL, in case of an error | |
124 | **/ | |
666fcf03 | 125 | UDEV_EXPORT struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path) |
ba6929f6 | 126 | { |
912541b0 KS |
127 | struct udev_monitor *udev_monitor; |
128 | struct stat statbuf; | |
129 | ||
130 | if (udev == NULL) | |
131 | return NULL; | |
132 | if (socket_path == NULL) | |
133 | return NULL; | |
134 | udev_monitor = udev_monitor_new(udev); | |
135 | if (udev_monitor == NULL) | |
136 | return NULL; | |
137 | ||
138 | udev_monitor->sun.sun_family = AF_LOCAL; | |
139 | if (socket_path[0] == '@') { | |
140 | /* translate leading '@' to abstract namespace */ | |
141 | util_strscpy(udev_monitor->sun.sun_path, sizeof(udev_monitor->sun.sun_path), socket_path); | |
142 | udev_monitor->sun.sun_path[0] = '\0'; | |
143 | udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path); | |
144 | } else if (stat(socket_path, &statbuf) == 0 && S_ISSOCK(statbuf.st_mode)) { | |
145 | /* existing socket file */ | |
146 | util_strscpy(udev_monitor->sun.sun_path, sizeof(udev_monitor->sun.sun_path), socket_path); | |
147 | udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path); | |
148 | } else { | |
149 | /* no socket file, assume abstract namespace socket */ | |
150 | util_strscpy(&udev_monitor->sun.sun_path[1], sizeof(udev_monitor->sun.sun_path)-1, socket_path); | |
151 | udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path)+1; | |
152 | } | |
153 | udev_monitor->sock = socket(AF_LOCAL, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0); | |
154 | if (udev_monitor->sock == -1) { | |
155 | err(udev, "error getting socket: %m\n"); | |
156 | free(udev_monitor); | |
157 | return NULL; | |
158 | } | |
159 | ||
160 | dbg(udev, "monitor %p created with '%s'\n", udev_monitor, socket_path); | |
161 | return udev_monitor; | |
d59f11e1 | 162 | } |
ba6929f6 | 163 | |
7459bcdc | 164 | struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) |
1c7047ea | 165 | { |
912541b0 KS |
166 | struct udev_monitor *udev_monitor; |
167 | unsigned int group; | |
168 | ||
169 | if (udev == NULL) | |
170 | return NULL; | |
171 | ||
172 | if (name == NULL) | |
173 | group = UDEV_MONITOR_NONE; | |
174 | else if (strcmp(name, "udev") == 0) | |
175 | group = UDEV_MONITOR_UDEV; | |
176 | else if (strcmp(name, "kernel") == 0) | |
177 | group = UDEV_MONITOR_KERNEL; | |
178 | else | |
179 | return NULL; | |
180 | ||
181 | udev_monitor = udev_monitor_new(udev); | |
182 | if (udev_monitor == NULL) | |
183 | return NULL; | |
184 | ||
185 | if (fd < 0) { | |
186 | udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); | |
187 | if (udev_monitor->sock == -1) { | |
188 | err(udev, "error getting socket: %m\n"); | |
189 | free(udev_monitor); | |
190 | return NULL; | |
191 | } | |
192 | } else { | |
193 | udev_monitor->bound = true; | |
194 | udev_monitor->sock = fd; | |
195 | } | |
196 | ||
197 | udev_monitor->snl.nl_family = AF_NETLINK; | |
198 | udev_monitor->snl.nl_groups = group; | |
199 | ||
200 | /* default destination for sending */ | |
201 | udev_monitor->snl_destination.nl_family = AF_NETLINK; | |
202 | udev_monitor->snl_destination.nl_groups = UDEV_MONITOR_UDEV; | |
203 | ||
204 | dbg(udev, "monitor %p created with NETLINK_KOBJECT_UEVENT (%u)\n", udev_monitor, group); | |
205 | return udev_monitor; | |
1c7047ea KS |
206 | } |
207 | ||
7459bcdc KS |
208 | /** |
209 | * udev_monitor_new_from_netlink: | |
210 | * @udev: udev library context | |
211 | * @name: name of event source | |
212 | * | |
213 | * Create new udev monitor and connect to a specified event | |
214 | * source. Valid sources identifiers are "udev" and "kernel". | |
215 | * | |
216 | * Applications should usually not connect directly to the | |
217 | * "kernel" events, because the devices might not be useable | |
218 | * at that time, before udev has configured them, and created | |
50579295 KS |
219 | * device nodes. Accessing devices at the same time as udev, |
220 | * might result in unpredictable behavior. The "udev" events | |
221 | * are sent out after udev has finished its event processing, | |
222 | * all rules have been processed, and needed device nodes are | |
223 | * created. | |
7459bcdc KS |
224 | * |
225 | * The initial refcount is 1, and needs to be decremented to | |
226 | * release the resources of the udev monitor. | |
227 | * | |
228 | * Returns: a new udev monitor, or #NULL, in case of an error | |
229 | **/ | |
666fcf03 | 230 | UDEV_EXPORT struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) |
7459bcdc | 231 | { |
912541b0 | 232 | return udev_monitor_new_from_netlink_fd(udev, name, -1); |
7459bcdc KS |
233 | } |
234 | ||
e14bdd88 | 235 | static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i, |
912541b0 | 236 | unsigned short code, unsigned int data) |
e14bdd88 | 237 | { |
912541b0 | 238 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 239 | |
912541b0 KS |
240 | ins->code = code; |
241 | ins->k = data; | |
242 | (*i)++; | |
e14bdd88 KS |
243 | } |
244 | ||
245 | static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i, | |
912541b0 KS |
246 | unsigned short code, unsigned int data, |
247 | unsigned short jt, unsigned short jf) | |
e14bdd88 | 248 | { |
912541b0 | 249 | struct sock_filter *ins = &inss[*i]; |
e14bdd88 | 250 | |
912541b0 KS |
251 | ins->code = code; |
252 | ins->jt = jt; | |
253 | ins->jf = jf; | |
254 | ins->k = data; | |
255 | (*i)++; | |
e14bdd88 KS |
256 | } |
257 | ||
ce1d6d7f KS |
258 | /** |
259 | * udev_monitor_filter_update: | |
260 | * @udev_monitor: monitor | |
261 | * | |
50579295 KS |
262 | * Update the installed socket filter. This is only needed, |
263 | * if the filter was removed or changed. | |
ce1d6d7f KS |
264 | * |
265 | * Returns: 0 on success, otherwise a negative error value. | |
266 | */ | |
666fcf03 | 267 | UDEV_EXPORT int udev_monitor_filter_update(struct udev_monitor *udev_monitor) |
e14bdd88 | 268 | { |
912541b0 KS |
269 | struct sock_filter ins[512]; |
270 | struct sock_fprog filter; | |
271 | unsigned int i; | |
272 | struct udev_list_entry *list_entry; | |
273 | int err; | |
274 | ||
275 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL && | |
276 | udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) | |
277 | return 0; | |
278 | ||
279 | memset(ins, 0x00, sizeof(ins)); | |
280 | i = 0; | |
281 | ||
282 | /* load magic in A */ | |
283 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic)); | |
284 | /* jump if magic matches */ | |
285 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); | |
286 | /* wrong magic, pass packet */ | |
287 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
288 | ||
289 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) { | |
290 | int tag_matches; | |
291 | ||
292 | /* count tag matches, to calculate end of tag match block */ | |
293 | tag_matches = 0; | |
294 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) | |
295 | tag_matches++; | |
296 | ||
297 | /* add all tags matches */ | |
298 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
299 | uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
300 | uint32_t tag_bloom_hi = tag_bloom_bits >> 32; | |
301 | uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; | |
302 | ||
303 | /* load device bloom bits in A */ | |
304 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi)); | |
305 | /* clear bits (tag bits & bloom bits) */ | |
306 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); | |
307 | /* jump to next tag if it does not match */ | |
308 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); | |
309 | ||
310 | /* load device bloom bits in A */ | |
311 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo)); | |
312 | /* clear bits (tag bits & bloom bits) */ | |
313 | bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); | |
314 | /* jump behind end of tag match block if tag matches */ | |
315 | tag_matches--; | |
316 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); | |
317 | } | |
318 | ||
319 | /* nothing matched, drop packet */ | |
320 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
321 | } | |
322 | ||
323 | /* add all subsystem matches */ | |
324 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) { | |
325 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
326 | unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry)); | |
327 | ||
328 | /* load device subsystem value in A */ | |
329 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash)); | |
330 | if (udev_list_entry_get_value(list_entry) == NULL) { | |
331 | /* jump if subsystem does not match */ | |
332 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
333 | } else { | |
334 | /* jump if subsystem does not match */ | |
335 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); | |
336 | ||
337 | /* load device devtype value in A */ | |
338 | bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash)); | |
339 | /* jump if value does not match */ | |
340 | hash = util_string_hash32(udev_list_entry_get_value(list_entry)); | |
341 | bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); | |
342 | } | |
343 | ||
344 | /* matched, pass packet */ | |
345 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
346 | ||
347 | if (i+1 >= ARRAY_SIZE(ins)) | |
348 | return -1; | |
349 | } | |
350 | ||
351 | /* nothing matched, drop packet */ | |
352 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); | |
353 | } | |
354 | ||
355 | /* matched, pass packet */ | |
356 | bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); | |
357 | ||
358 | /* install filter */ | |
359 | memset(&filter, 0x00, sizeof(filter)); | |
360 | filter.len = i; | |
361 | filter.filter = ins; | |
362 | err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
363 | return err; | |
e14bdd88 KS |
364 | } |
365 | ||
1e03b754 KS |
366 | int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
367 | { | |
912541b0 KS |
368 | udev_monitor->snl_trusted_sender.nl_pid = sender->snl.nl_pid; |
369 | return 0; | |
1e03b754 | 370 | } |
ce1d6d7f KS |
371 | /** |
372 | * udev_monitor_enable_receiving: | |
373 | * @udev_monitor: the monitor which should receive events | |
374 | * | |
375 | * Binds the @udev_monitor socket to the event source. | |
376 | * | |
377 | * Returns: 0 on success, otherwise a negative error value. | |
378 | */ | |
666fcf03 | 379 | UDEV_EXPORT int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
d59f11e1 | 380 | { |
912541b0 KS |
381 | int err = 0; |
382 | const int on = 1; | |
383 | ||
384 | if (udev_monitor->sun.sun_family != 0) { | |
385 | if (!udev_monitor->bound) { | |
386 | err = bind(udev_monitor->sock, | |
387 | (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen); | |
388 | if (err == 0) | |
389 | udev_monitor->bound = true; | |
390 | } | |
391 | } else if (udev_monitor->snl.nl_family != 0) { | |
392 | udev_monitor_filter_update(udev_monitor); | |
393 | if (!udev_monitor->bound) { | |
394 | err = bind(udev_monitor->sock, | |
395 | (struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl)); | |
396 | if (err == 0) | |
397 | udev_monitor->bound = true; | |
398 | } | |
399 | if (err == 0) { | |
400 | struct sockaddr_nl snl; | |
401 | socklen_t addrlen; | |
402 | ||
403 | /* | |
404 | * get the address the kernel has assigned us | |
405 | * it is usually, but not necessarily the pid | |
406 | */ | |
407 | addrlen = sizeof(struct sockaddr_nl); | |
408 | err = getsockname(udev_monitor->sock, (struct sockaddr *)&snl, &addrlen); | |
409 | if (err == 0) | |
410 | udev_monitor->snl.nl_pid = snl.nl_pid; | |
411 | } | |
412 | } else { | |
413 | return -EINVAL; | |
414 | } | |
415 | ||
416 | if (err < 0) { | |
417 | err(udev_monitor->udev, "bind failed: %m\n"); | |
418 | return err; | |
419 | } | |
420 | ||
421 | /* enable receiving of sender credentials */ | |
422 | setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); | |
423 | return 0; | |
ba6929f6 KS |
424 | } |
425 | ||
f712894d KS |
426 | /** |
427 | * udev_monitor_set_receive_buffer_size: | |
428 | * @udev_monitor: the monitor which should receive events | |
429 | * @size: the size in bytes | |
430 | * | |
431 | * Set the size of the kernel socket buffer. This call needs the | |
432 | * appropriate privileges to succeed. | |
433 | * | |
434 | * Returns: 0 on success, otherwise -1 on error. | |
435 | */ | |
666fcf03 | 436 | UDEV_EXPORT int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
cb25a958 | 437 | { |
912541b0 KS |
438 | if (udev_monitor == NULL) |
439 | return -1; | |
440 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)); | |
cb25a958 KS |
441 | } |
442 | ||
1e03b754 KS |
443 | int udev_monitor_disconnect(struct udev_monitor *udev_monitor) |
444 | { | |
912541b0 | 445 | int err; |
1e03b754 | 446 | |
912541b0 KS |
447 | err = close(udev_monitor->sock); |
448 | udev_monitor->sock = -1; | |
449 | return err; | |
1e03b754 KS |
450 | } |
451 | ||
7d8787b3 KS |
452 | /** |
453 | * udev_monitor_ref: | |
454 | * @udev_monitor: udev monitor | |
455 | * | |
456 | * Take a reference of a udev monitor. | |
457 | * | |
458 | * Returns: the passed udev monitor | |
459 | **/ | |
666fcf03 | 460 | UDEV_EXPORT struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor) |
ba6929f6 | 461 | { |
912541b0 KS |
462 | if (udev_monitor == NULL) |
463 | return NULL; | |
464 | udev_monitor->refcount++; | |
465 | return udev_monitor; | |
ba6929f6 KS |
466 | } |
467 | ||
7d8787b3 KS |
468 | /** |
469 | * udev_monitor_unref: | |
470 | * @udev_monitor: udev monitor | |
471 | * | |
ff109b8d | 472 | * Drop a reference of a udev monitor. If the refcount reaches zero, |
be7de409 | 473 | * the bound socket will be closed, and the resources of the monitor |
7d8787b3 KS |
474 | * will be released. |
475 | * | |
476 | **/ | |
666fcf03 | 477 | UDEV_EXPORT void udev_monitor_unref(struct udev_monitor *udev_monitor) |
ba6929f6 | 478 | { |
912541b0 KS |
479 | if (udev_monitor == NULL) |
480 | return; | |
481 | udev_monitor->refcount--; | |
482 | if (udev_monitor->refcount > 0) | |
483 | return; | |
484 | if (udev_monitor->sock >= 0) | |
485 | close(udev_monitor->sock); | |
486 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); | |
487 | udev_list_cleanup(&udev_monitor->filter_tag_list); | |
488 | dbg(udev_monitor->udev, "monitor %p released\n", udev_monitor); | |
489 | free(udev_monitor); | |
ba6929f6 KS |
490 | } |
491 | ||
7d8787b3 KS |
492 | /** |
493 | * udev_monitor_get_udev: | |
494 | * @udev_monitor: udev monitor | |
495 | * | |
b98fd840 | 496 | * Retrieve the udev library context the monitor was created with. |
7d8787b3 KS |
497 | * |
498 | * Returns: the udev library context | |
499 | **/ | |
666fcf03 | 500 | UDEV_EXPORT struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor) |
ba6929f6 | 501 | { |
912541b0 KS |
502 | if (udev_monitor == NULL) |
503 | return NULL; | |
504 | return udev_monitor->udev; | |
ba6929f6 KS |
505 | } |
506 | ||
7d8787b3 KS |
507 | /** |
508 | * udev_monitor_get_fd: | |
509 | * @udev_monitor: udev monitor | |
510 | * | |
511 | * Retrieve the socket file descriptor associated with the monitor. | |
512 | * | |
513 | * Returns: the socket file descriptor | |
514 | **/ | |
666fcf03 | 515 | UDEV_EXPORT int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
ba6929f6 | 516 | { |
912541b0 KS |
517 | if (udev_monitor == NULL) |
518 | return -1; | |
519 | return udev_monitor->sock; | |
ba6929f6 KS |
520 | } |
521 | ||
e14bdd88 KS |
522 | static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device) |
523 | { | |
912541b0 KS |
524 | struct udev_list_entry *list_entry; |
525 | ||
526 | if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL) | |
527 | goto tag; | |
528 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) { | |
529 | const char *subsys = udev_list_entry_get_name(list_entry); | |
530 | const char *dsubsys = udev_device_get_subsystem(udev_device); | |
531 | const char *devtype; | |
532 | const char *ddevtype; | |
533 | ||
534 | if (strcmp(dsubsys, subsys) != 0) | |
535 | continue; | |
536 | ||
537 | devtype = udev_list_entry_get_value(list_entry); | |
538 | if (devtype == NULL) | |
539 | goto tag; | |
540 | ddevtype = udev_device_get_devtype(udev_device); | |
541 | if (ddevtype == NULL) | |
542 | continue; | |
543 | if (strcmp(ddevtype, devtype) == 0) | |
544 | goto tag; | |
545 | } | |
546 | return 0; | |
28460195 KS |
547 | |
548 | tag: | |
912541b0 KS |
549 | if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL) |
550 | return 1; | |
551 | udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) { | |
552 | const char *tag = udev_list_entry_get_name(list_entry); | |
553 | ||
554 | if (udev_device_has_tag(udev_device, tag)) | |
555 | return 1; | |
556 | } | |
557 | return 0; | |
e14bdd88 KS |
558 | } |
559 | ||
7d8787b3 | 560 | /** |
d59f11e1 | 561 | * udev_monitor_receive_device: |
7d8787b3 KS |
562 | * @udev_monitor: udev monitor |
563 | * | |
d59f11e1 | 564 | * Receive data from the udev monitor socket, allocate a new udev |
b98fd840 | 565 | * device, fill in the received data, and return the device. |
7d8787b3 | 566 | * |
50579295 | 567 | * Only socket connections with uid=0 are accepted. |
7d8787b3 KS |
568 | * |
569 | * The initial refcount is 1, and needs to be decremented to | |
be7de409 | 570 | * release the resources of the udev device. |
7d8787b3 KS |
571 | * |
572 | * Returns: a new udev device, or #NULL, in case of an error | |
573 | **/ | |
666fcf03 | 574 | UDEV_EXPORT struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor) |
ba6929f6 | 575 | { |
912541b0 KS |
576 | struct udev_device *udev_device; |
577 | struct msghdr smsg; | |
578 | struct iovec iov; | |
579 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
580 | struct cmsghdr *cmsg; | |
581 | struct sockaddr_nl snl; | |
582 | struct ucred *cred; | |
583 | char buf[8192]; | |
584 | ssize_t buflen; | |
585 | ssize_t bufpos; | |
586 | struct udev_monitor_netlink_header *nlh; | |
ba6929f6 | 587 | |
e14bdd88 | 588 | retry: |
912541b0 KS |
589 | if (udev_monitor == NULL) |
590 | return NULL; | |
912541b0 KS |
591 | iov.iov_base = &buf; |
592 | iov.iov_len = sizeof(buf); | |
593 | memset (&smsg, 0x00, sizeof(struct msghdr)); | |
594 | smsg.msg_iov = &iov; | |
595 | smsg.msg_iovlen = 1; | |
596 | smsg.msg_control = cred_msg; | |
597 | smsg.msg_controllen = sizeof(cred_msg); | |
598 | ||
599 | if (udev_monitor->snl.nl_family != 0) { | |
600 | smsg.msg_name = &snl; | |
601 | smsg.msg_namelen = sizeof(snl); | |
602 | } | |
603 | ||
604 | buflen = recvmsg(udev_monitor->sock, &smsg, 0); | |
605 | if (buflen < 0) { | |
606 | if (errno != EINTR) | |
607 | info(udev_monitor->udev, "unable to receive message\n"); | |
608 | return NULL; | |
609 | } | |
610 | ||
611 | if (buflen < 32 || (size_t)buflen >= sizeof(buf)) { | |
612 | info(udev_monitor->udev, "invalid message length\n"); | |
613 | return NULL; | |
614 | } | |
615 | ||
616 | if (udev_monitor->snl.nl_family != 0) { | |
617 | if (snl.nl_groups == 0) { | |
618 | /* unicast message, check if we trust the sender */ | |
619 | if (udev_monitor->snl_trusted_sender.nl_pid == 0 || | |
620 | snl.nl_pid != udev_monitor->snl_trusted_sender.nl_pid) { | |
621 | info(udev_monitor->udev, "unicast netlink message ignored\n"); | |
622 | return NULL; | |
623 | } | |
624 | } else if (snl.nl_groups == UDEV_MONITOR_KERNEL) { | |
625 | if (snl.nl_pid > 0) { | |
626 | info(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n", | |
627 | snl.nl_pid); | |
628 | return NULL; | |
629 | } | |
630 | } | |
631 | } | |
632 | ||
633 | cmsg = CMSG_FIRSTHDR(&smsg); | |
634 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | |
635 | info(udev_monitor->udev, "no sender credentials received, message ignored\n"); | |
636 | return NULL; | |
637 | } | |
638 | ||
639 | cred = (struct ucred *)CMSG_DATA(cmsg); | |
640 | if (cred->uid != 0) { | |
641 | info(udev_monitor->udev, "sender uid=%d, message ignored\n", cred->uid); | |
642 | return NULL; | |
643 | } | |
644 | ||
645 | if (memcmp(buf, "libudev", 8) == 0) { | |
646 | /* udev message needs proper version magic */ | |
647 | nlh = (struct udev_monitor_netlink_header *) buf; | |
648 | if (nlh->magic != htonl(UDEV_MONITOR_MAGIC)) { | |
649 | err(udev_monitor->udev, "unrecognized message signature (%x != %x)\n", | |
650 | nlh->magic, htonl(UDEV_MONITOR_MAGIC)); | |
651 | return NULL; | |
652 | } | |
653 | if (nlh->properties_off+32 > buflen) | |
654 | return NULL; | |
655 | bufpos = nlh->properties_off; | |
656 | } else { | |
657 | /* kernel message with header */ | |
658 | bufpos = strlen(buf) + 1; | |
659 | if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { | |
660 | info(udev_monitor->udev, "invalid message length\n"); | |
661 | return NULL; | |
662 | } | |
663 | ||
664 | /* check message header */ | |
665 | if (strstr(buf, "@/") == NULL) { | |
666 | info(udev_monitor->udev, "unrecognized message header\n"); | |
667 | return NULL; | |
668 | } | |
669 | } | |
670 | ||
671 | udev_device = udev_device_new(udev_monitor->udev); | |
672 | if (udev_device == NULL) | |
673 | return NULL; | |
674 | udev_device_set_info_loaded(udev_device); | |
675 | ||
676 | while (bufpos < buflen) { | |
677 | char *key; | |
678 | size_t keylen; | |
679 | ||
680 | key = &buf[bufpos]; | |
681 | keylen = strlen(key); | |
682 | if (keylen == 0) | |
683 | break; | |
684 | bufpos += keylen + 1; | |
685 | udev_device_add_property_from_string_parse(udev_device, key); | |
686 | } | |
687 | ||
688 | if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) { | |
689 | info(udev_monitor->udev, "missing values, invalid device\n"); | |
690 | udev_device_unref(udev_device); | |
691 | return NULL; | |
692 | } | |
693 | ||
694 | /* skip device, if it does not pass the current filter */ | |
695 | if (!passes_filter(udev_monitor, udev_device)) { | |
696 | struct pollfd pfd[1]; | |
697 | int rc; | |
698 | ||
699 | udev_device_unref(udev_device); | |
700 | ||
701 | /* if something is queued, get next device */ | |
702 | pfd[0].fd = udev_monitor->sock; | |
703 | pfd[0].events = POLLIN; | |
704 | rc = poll(pfd, 1, 0); | |
705 | if (rc > 0) | |
706 | goto retry; | |
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 | { |
912541b0 KS |
716 | const char *buf; |
717 | ssize_t blen; | |
718 | ssize_t count; | |
719 | ||
720 | blen = udev_device_get_properties_monitor_buf(udev_device, &buf); | |
721 | if (blen < 32) | |
722 | return -EINVAL; | |
723 | ||
724 | if (udev_monitor->sun.sun_family != 0) { | |
725 | struct msghdr smsg; | |
726 | struct iovec iov[2]; | |
727 | const char *action; | |
728 | char header[2048]; | |
729 | char *s; | |
730 | ||
731 | /* header <action>@<devpath> */ | |
732 | action = udev_device_get_action(udev_device); | |
733 | if (action == NULL) | |
734 | return -EINVAL; | |
735 | s = header; | |
736 | if (util_strpcpyl(&s, sizeof(header), action, "@", udev_device_get_devpath(udev_device), NULL) == 0) | |
737 | return -EINVAL; | |
738 | iov[0].iov_base = header; | |
739 | iov[0].iov_len = (s - header)+1; | |
740 | ||
741 | /* add properties list */ | |
742 | iov[1].iov_base = (char *)buf; | |
743 | iov[1].iov_len = blen; | |
744 | ||
745 | memset(&smsg, 0x00, sizeof(struct msghdr)); | |
746 | smsg.msg_iov = iov; | |
747 | smsg.msg_iovlen = 2; | |
748 | smsg.msg_name = &udev_monitor->sun; | |
749 | smsg.msg_namelen = udev_monitor->addrlen; | |
750 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
751 | info(udev_monitor->udev, "passed %zi bytes to socket monitor %p\n", count, udev_monitor); | |
752 | return count; | |
753 | } | |
754 | ||
755 | if (udev_monitor->snl.nl_family != 0) { | |
756 | struct msghdr smsg; | |
757 | struct iovec iov[2]; | |
758 | const char *val; | |
759 | struct udev_monitor_netlink_header nlh; | |
760 | struct udev_list_entry *list_entry; | |
761 | uint64_t tag_bloom_bits; | |
762 | ||
763 | /* add versioned header */ | |
764 | memset(&nlh, 0x00, sizeof(struct udev_monitor_netlink_header)); | |
765 | memcpy(nlh.prefix, "libudev", 8); | |
766 | nlh.magic = htonl(UDEV_MONITOR_MAGIC); | |
767 | nlh.header_size = sizeof(struct udev_monitor_netlink_header); | |
768 | val = udev_device_get_subsystem(udev_device); | |
769 | nlh.filter_subsystem_hash = htonl(util_string_hash32(val)); | |
770 | val = udev_device_get_devtype(udev_device); | |
771 | if (val != NULL) | |
772 | nlh.filter_devtype_hash = htonl(util_string_hash32(val)); | |
773 | iov[0].iov_base = &nlh; | |
774 | iov[0].iov_len = sizeof(struct udev_monitor_netlink_header); | |
775 | ||
776 | /* add tag bloom filter */ | |
777 | tag_bloom_bits = 0; | |
778 | udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device)) | |
779 | tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry)); | |
780 | if (tag_bloom_bits > 0) { | |
781 | nlh.filter_tag_bloom_hi = htonl(tag_bloom_bits >> 32); | |
782 | nlh.filter_tag_bloom_lo = htonl(tag_bloom_bits & 0xffffffff); | |
783 | } | |
784 | ||
785 | /* add properties list */ | |
786 | nlh.properties_off = iov[0].iov_len; | |
787 | nlh.properties_len = blen; | |
788 | iov[1].iov_base = (char *)buf; | |
789 | iov[1].iov_len = blen; | |
790 | ||
791 | memset(&smsg, 0x00, sizeof(struct msghdr)); | |
792 | smsg.msg_iov = iov; | |
793 | smsg.msg_iovlen = 2; | |
794 | /* | |
795 | * Use custom address for target, or the default one. | |
796 | * | |
797 | * If we send to a multicast group, we will get | |
798 | * ECONNREFUSED, which is expected. | |
799 | */ | |
800 | if (destination != NULL) | |
801 | smsg.msg_name = &destination->snl; | |
802 | else | |
803 | smsg.msg_name = &udev_monitor->snl_destination; | |
804 | smsg.msg_namelen = sizeof(struct sockaddr_nl); | |
805 | count = sendmsg(udev_monitor->sock, &smsg, 0); | |
806 | info(udev_monitor->udev, "passed %zi bytes to netlink monitor %p\n", count, udev_monitor); | |
807 | return count; | |
808 | } | |
809 | ||
810 | return -EINVAL; | |
9925ab04 | 811 | } |
e14bdd88 | 812 | |
ce1d6d7f KS |
813 | /** |
814 | * udev_monitor_filter_add_match_subsystem_devtype: | |
815 | * @udev_monitor: the monitor | |
816 | * @subsystem: the subsystem value to match the incoming devices against | |
214a6c79 | 817 | * @devtype: the devtype value to match the incoming devices against |
ce1d6d7f | 818 | * |
50579295 | 819 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
820 | * will usually not be woken up for devices which do not match. |
821 | * | |
ce1d6d7f KS |
822 | * The filter must be installed before the monitor is switched to listening mode. |
823 | * | |
824 | * Returns: 0 on success, otherwise a negative error value. | |
825 | */ | |
666fcf03 | 826 | UDEV_EXPORT int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype) |
e14bdd88 | 827 | { |
912541b0 KS |
828 | if (udev_monitor == NULL) |
829 | return -EINVAL; | |
830 | if (subsystem == NULL) | |
831 | return -EINVAL; | |
832 | if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL) | |
833 | return -ENOMEM; | |
834 | return 0; | |
e14bdd88 | 835 | } |
08a7a795 | 836 | |
28460195 KS |
837 | /** |
838 | * udev_monitor_filter_add_match_tag: | |
839 | * @udev_monitor: the monitor | |
840 | * @tag: the name of a tag | |
841 | * | |
50579295 | 842 | * This filter is efficiently executed inside the kernel, and libudev subscribers |
28460195 KS |
843 | * will usually not be woken up for devices which do not match. |
844 | * | |
845 | * The filter must be installed before the monitor is switched to listening mode. | |
846 | * | |
847 | * Returns: 0 on success, otherwise a negative error value. | |
848 | */ | |
666fcf03 | 849 | UDEV_EXPORT int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag) |
28460195 | 850 | { |
912541b0 KS |
851 | if (udev_monitor == NULL) |
852 | return -EINVAL; | |
853 | if (tag == NULL) | |
854 | return -EINVAL; | |
855 | if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL) | |
856 | return -ENOMEM; | |
857 | return 0; | |
28460195 KS |
858 | } |
859 | ||
ce1d6d7f KS |
860 | /** |
861 | * udev_monitor_filter_remove: | |
862 | * @udev_monitor: monitor | |
863 | * | |
864 | * Remove all filters from monitor. | |
865 | * | |
866 | * Returns: 0 on success, otherwise a negative error value. | |
867 | */ | |
666fcf03 | 868 | UDEV_EXPORT int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
08a7a795 | 869 | { |
912541b0 | 870 | static struct sock_fprog filter = { 0, NULL }; |
08a7a795 | 871 | |
912541b0 KS |
872 | udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
873 | return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); | |
08a7a795 | 874 | } |