2 * libudev - interface to udev device information
4 * Copyright (C) 2008-2010 Kay Sievers <kay.sievers@vrfy.org>
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.
21 #include <sys/socket.h>
23 #include <arpa/inet.h>
24 #include <linux/netlink.h>
25 #include <linux/filter.h>
28 #include "libudev-private.h"
31 * SECTION:libudev-monitor
32 * @short_description: device event source
34 * Connects to a device event source.
40 * Opaque object handling an event source.
46 struct sockaddr_nl snl;
47 struct sockaddr_nl snl_trusted_sender;
48 struct sockaddr_nl snl_destination;
49 struct sockaddr_un sun;
51 struct udev_list filter_subsystem_list;
52 struct udev_list filter_tag_list;
56 enum udev_monitor_netlink_group {
62 #define UDEV_MONITOR_MAGIC 0xfeedcafe
63 struct udev_monitor_netlink_header {
64 /* "libudev" prefix to distinguish libudev and kernel messages */
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
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;
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
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;
86 static struct udev_monitor *udev_monitor_new(struct udev *udev)
88 struct udev_monitor *udev_monitor;
90 udev_monitor = calloc(1, sizeof(struct udev_monitor));
91 if (udev_monitor == 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);
101 * udev_monitor_new_from_socket:
102 * @udev: udev library context
103 * @socket_path: unix socket path
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
110 * Create a new udev monitor and connect to a specified socket. The
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
113 * socket will be used.
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.
120 * The initial refcount is 1, and needs to be decremented to
121 * release the resources of the udev monitor.
123 * Returns: a new udev monitor, or #NULL, in case of an error
125 UDEV_EXPORT struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path)
127 struct udev_monitor *udev_monitor;
132 if (socket_path == NULL)
134 udev_monitor = udev_monitor_new(udev);
135 if (udev_monitor == NULL)
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);
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;
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");
160 dbg(udev, "monitor %p created with '%s'\n", udev_monitor, socket_path);
164 struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd)
166 struct udev_monitor *udev_monitor;
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;
181 udev_monitor = udev_monitor_new(udev);
182 if (udev_monitor == NULL)
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");
193 udev_monitor->bound = true;
194 udev_monitor->sock = fd;
197 udev_monitor->snl.nl_family = AF_NETLINK;
198 udev_monitor->snl.nl_groups = group;
200 /* default destination for sending */
201 udev_monitor->snl_destination.nl_family = AF_NETLINK;
202 udev_monitor->snl_destination.nl_groups = UDEV_MONITOR_UDEV;
204 dbg(udev, "monitor %p created with NETLINK_KOBJECT_UEVENT (%u)\n", udev_monitor, group);
209 * udev_monitor_new_from_netlink:
210 * @udev: udev library context
211 * @name: name of event source
213 * Create new udev monitor and connect to a specified event
214 * source. Valid sources identifiers are "udev" and "kernel".
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
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
225 * The initial refcount is 1, and needs to be decremented to
226 * release the resources of the udev monitor.
228 * Returns: a new udev monitor, or #NULL, in case of an error
230 UDEV_EXPORT struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name)
232 return udev_monitor_new_from_netlink_fd(udev, name, -1);
235 static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i,
236 unsigned short code, unsigned int data)
238 struct sock_filter *ins = &inss[*i];
245 static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i,
246 unsigned short code, unsigned int data,
247 unsigned short jt, unsigned short jf)
249 struct sock_filter *ins = &inss[*i];
259 * udev_monitor_filter_update:
260 * @udev_monitor: monitor
262 * Update the installed socket filter. This is only needed,
263 * if the filter was removed or changed.
265 * Returns: 0 on success, otherwise a negative error value.
267 UDEV_EXPORT int udev_monitor_filter_update(struct udev_monitor *udev_monitor)
269 struct sock_filter ins[512];
270 struct sock_fprog filter;
272 struct udev_list_entry *list_entry;
275 if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL &&
276 udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL)
279 memset(ins, 0x00, sizeof(ins));
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);
289 if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) {
292 /* count tag matches, to calculate end of tag match block */
294 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list))
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;
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);
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 */
316 bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0);
319 /* nothing matched, drop packet */
320 bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
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));
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);
334 /* jump if subsystem does not match */
335 bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3);
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);
344 /* matched, pass packet */
345 bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
347 if (i+1 >= ARRAY_SIZE(ins))
351 /* nothing matched, drop packet */
352 bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
355 /* matched, pass packet */
356 bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
359 memset(&filter, 0x00, sizeof(filter));
362 err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter));
366 int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender)
368 udev_monitor->snl_trusted_sender.nl_pid = sender->snl.nl_pid;
372 * udev_monitor_enable_receiving:
373 * @udev_monitor: the monitor which should receive events
375 * Binds the @udev_monitor socket to the event source.
377 * Returns: 0 on success, otherwise a negative error value.
379 UDEV_EXPORT int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
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);
389 udev_monitor->bound = true;
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));
397 udev_monitor->bound = true;
400 struct sockaddr_nl snl;
404 * get the address the kernel has assigned us
405 * it is usually, but not necessarily the pid
407 addrlen = sizeof(struct sockaddr_nl);
408 err = getsockname(udev_monitor->sock, (struct sockaddr *)&snl, &addrlen);
410 udev_monitor->snl.nl_pid = snl.nl_pid;
417 err(udev_monitor->udev, "bind failed: %m\n");
421 /* enable receiving of sender credentials */
422 setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
427 * udev_monitor_set_receive_buffer_size:
428 * @udev_monitor: the monitor which should receive events
429 * @size: the size in bytes
431 * Set the size of the kernel socket buffer. This call needs the
432 * appropriate privileges to succeed.
434 * Returns: 0 on success, otherwise -1 on error.
436 UDEV_EXPORT int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size)
438 if (udev_monitor == NULL)
440 return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size));
443 int udev_monitor_disconnect(struct udev_monitor *udev_monitor)
447 err = close(udev_monitor->sock);
448 udev_monitor->sock = -1;
454 * @udev_monitor: udev monitor
456 * Take a reference of a udev monitor.
458 * Returns: the passed udev monitor
460 UDEV_EXPORT struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
462 if (udev_monitor == NULL)
464 udev_monitor->refcount++;
469 * udev_monitor_unref:
470 * @udev_monitor: udev monitor
472 * Drop a reference of a udev monitor. If the refcount reaches zero,
473 * the bound socket will be closed, and the resources of the monitor
477 UDEV_EXPORT void udev_monitor_unref(struct udev_monitor *udev_monitor)
479 if (udev_monitor == NULL)
481 udev_monitor->refcount--;
482 if (udev_monitor->refcount > 0)
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);
493 * udev_monitor_get_udev:
494 * @udev_monitor: udev monitor
496 * Retrieve the udev library context the monitor was created with.
498 * Returns: the udev library context
500 UDEV_EXPORT struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
502 if (udev_monitor == NULL)
504 return udev_monitor->udev;
508 * udev_monitor_get_fd:
509 * @udev_monitor: udev monitor
511 * Retrieve the socket file descriptor associated with the monitor.
513 * Returns: the socket file descriptor
515 UDEV_EXPORT int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
517 if (udev_monitor == NULL)
519 return udev_monitor->sock;
522 static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device)
524 struct udev_list_entry *list_entry;
526 if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL)
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);
532 const char *ddevtype;
534 if (strcmp(dsubsys, subsys) != 0)
537 devtype = udev_list_entry_get_value(list_entry);
540 ddevtype = udev_device_get_devtype(udev_device);
541 if (ddevtype == NULL)
543 if (strcmp(ddevtype, devtype) == 0)
549 if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL)
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);
554 if (udev_device_has_tag(udev_device, tag))
561 * udev_monitor_receive_device:
562 * @udev_monitor: udev monitor
564 * Receive data from the udev monitor socket, allocate a new udev
565 * device, fill in the received data, and return the device.
567 * Only socket connections with uid=0 are accepted.
569 * The initial refcount is 1, and needs to be decremented to
570 * release the resources of the udev device.
572 * Returns: a new udev device, or #NULL, in case of an error
574 UDEV_EXPORT struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
576 struct udev_device *udev_device;
579 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
580 struct cmsghdr *cmsg;
581 struct sockaddr_nl snl;
586 struct udev_monitor_netlink_header *nlh;
589 if (udev_monitor == NULL)
592 iov.iov_len = sizeof(buf);
593 memset (&smsg, 0x00, sizeof(struct msghdr));
596 smsg.msg_control = cred_msg;
597 smsg.msg_controllen = sizeof(cred_msg);
599 if (udev_monitor->snl.nl_family != 0) {
600 smsg.msg_name = &snl;
601 smsg.msg_namelen = sizeof(snl);
604 buflen = recvmsg(udev_monitor->sock, &smsg, 0);
607 info(udev_monitor->udev, "unable to receive message\n");
611 if (buflen < 32 || (size_t)buflen >= sizeof(buf)) {
612 info(udev_monitor->udev, "invalid message length\n");
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");
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",
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");
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);
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));
653 if (nlh->properties_off+32 > buflen)
655 bufpos = nlh->properties_off;
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");
664 /* check message header */
665 if (strstr(buf, "@/") == NULL) {
666 info(udev_monitor->udev, "unrecognized message header\n");
671 udev_device = udev_device_new(udev_monitor->udev);
672 if (udev_device == NULL)
674 udev_device_set_info_loaded(udev_device);
676 while (bufpos < buflen) {
681 keylen = strlen(key);
684 bufpos += keylen + 1;
685 udev_device_add_property_from_string_parse(udev_device, key);
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);
694 /* skip device, if it does not pass the current filter */
695 if (!passes_filter(udev_monitor, udev_device)) {
696 struct pollfd pfd[1];
699 udev_device_unref(udev_device);
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);
713 int udev_monitor_send_device(struct udev_monitor *udev_monitor,
714 struct udev_monitor *destination, struct udev_device *udev_device)
720 blen = udev_device_get_properties_monitor_buf(udev_device, &buf);
724 if (udev_monitor->sun.sun_family != 0) {
731 /* header <action>@<devpath> */
732 action = udev_device_get_action(udev_device);
736 if (util_strpcpyl(&s, sizeof(header), action, "@", udev_device_get_devpath(udev_device), NULL) == 0)
738 iov[0].iov_base = header;
739 iov[0].iov_len = (s - header)+1;
741 /* add properties list */
742 iov[1].iov_base = (char *)buf;
743 iov[1].iov_len = blen;
745 memset(&smsg, 0x00, sizeof(struct msghdr));
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);
755 if (udev_monitor->snl.nl_family != 0) {
759 struct udev_monitor_netlink_header nlh;
760 struct udev_list_entry *list_entry;
761 uint64_t tag_bloom_bits;
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);
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);
776 /* add tag bloom filter */
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);
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;
791 memset(&smsg, 0x00, sizeof(struct msghdr));
795 * Use custom address for target, or the default one.
797 * If we send to a multicast group, we will get
798 * ECONNREFUSED, which is expected.
800 if (destination != NULL)
801 smsg.msg_name = &destination->snl;
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);
814 * udev_monitor_filter_add_match_subsystem_devtype:
815 * @udev_monitor: the monitor
816 * @subsystem: the subsystem value to match the incoming devices against
817 * @devtype: the devtype value to match the incoming devices against
819 * This filter is efficiently executed inside the kernel, and libudev subscribers
820 * will usually not be woken up for devices which do not match.
822 * The filter must be installed before the monitor is switched to listening mode.
824 * Returns: 0 on success, otherwise a negative error value.
826 UDEV_EXPORT int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype)
828 if (udev_monitor == NULL)
830 if (subsystem == NULL)
832 if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL)
838 * udev_monitor_filter_add_match_tag:
839 * @udev_monitor: the monitor
840 * @tag: the name of a tag
842 * This filter is efficiently executed inside the kernel, and libudev subscribers
843 * will usually not be woken up for devices which do not match.
845 * The filter must be installed before the monitor is switched to listening mode.
847 * Returns: 0 on success, otherwise a negative error value.
849 UDEV_EXPORT int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag)
851 if (udev_monitor == NULL)
855 if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL)
861 * udev_monitor_filter_remove:
862 * @udev_monitor: monitor
864 * Remove all filters from monitor.
866 * Returns: 0 on success, otherwise a negative error value.
868 UDEV_EXPORT int udev_monitor_filter_remove(struct udev_monitor *udev_monitor)
870 static struct sock_fprog filter = { 0, NULL };
872 udev_list_cleanup(&udev_monitor->filter_subsystem_list);
873 return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter));