2 This file is part of systemd.
4 Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
29 #include <sys/socket.h>
31 #include <arpa/inet.h>
32 #include <linux/netlink.h>
33 #include <linux/filter.h>
36 #include "libudev-private.h"
37 #include "socket-util.h"
41 * SECTION:libudev-monitor
42 * @short_description: device event source
44 * Connects to a device event source.
50 * Opaque object handling an event source.
56 union sockaddr_union snl;
57 union sockaddr_union snl_trusted_sender;
58 union sockaddr_union snl_destination;
60 struct udev_list filter_subsystem_list;
61 struct udev_list filter_tag_list;
65 enum udev_monitor_netlink_group {
71 #define UDEV_MONITOR_MAGIC 0xfeedcafe
72 struct udev_monitor_netlink_header {
73 /* "libudev" prefix to distinguish libudev and kernel messages */
76 * magic to protect against daemon <-> library message format mismatch
77 * used in the kernel from socket filter rules; needs to be stored in network order
80 /* total length of header structure known to the sender */
81 unsigned int header_size;
82 /* properties string buffer */
83 unsigned int properties_off;
84 unsigned int properties_len;
86 * hashes of primary device properties strings, to let libudev subscribers
87 * use in-kernel socket filters; values need to be stored in network order
89 unsigned int filter_subsystem_hash;
90 unsigned int filter_devtype_hash;
91 unsigned int filter_tag_bloom_hi;
92 unsigned int filter_tag_bloom_lo;
95 static struct udev_monitor *udev_monitor_new(struct udev *udev)
97 struct udev_monitor *udev_monitor;
99 udev_monitor = new0(struct udev_monitor, 1);
100 if (udev_monitor == NULL)
102 udev_monitor->refcount = 1;
103 udev_monitor->udev = udev;
104 udev_list_init(udev, &udev_monitor->filter_subsystem_list, false);
105 udev_list_init(udev, &udev_monitor->filter_tag_list, true);
109 /* we consider udev running when /dev is on devtmpfs */
110 static bool udev_has_devtmpfs(struct udev *udev) {
111 struct file_handle *h;
113 _cleanup_fclose_ FILE *f = NULL;
114 char line[LINE_MAX], *e;
117 h = alloca(MAX_HANDLE_SZ);
118 h->handle_bytes = MAX_HANDLE_SZ;
119 r = name_to_handle_at(AT_FDCWD, "/dev", h, &mount_id, 0);
124 f = fopen("/proc/self/mountinfo", "re");
128 FOREACH_LINE(line, f, return false) {
131 if (sscanf(line, "%i", &mid) != 1)
137 e = strstr(line, " - ");
141 /* accept any name that starts with the currently expected type */
142 if (startswith(e + 3, "devtmpfs"))
149 struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd)
151 struct udev_monitor *udev_monitor;
158 group = UDEV_MONITOR_NONE;
159 else if (streq(name, "udev")) {
161 * We do not support subscribing to uevents if no instance of
162 * udev is running. Uevents would otherwise broadcast the
163 * processing data of the host into containers, which is not
166 * Containers will currently not get any udev uevents, until
167 * a supporting infrastructure is available.
169 * We do not set a netlink multicast group here, so the socket
170 * will not receive any messages.
172 if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) {
173 udev_dbg(udev, "the udev service seems not to be active, disable the monitor\n");
174 group = UDEV_MONITOR_NONE;
176 group = UDEV_MONITOR_UDEV;
177 } else if (streq(name, "kernel"))
178 group = UDEV_MONITOR_KERNEL;
182 udev_monitor = udev_monitor_new(udev);
183 if (udev_monitor == NULL)
187 udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT);
188 if (udev_monitor->sock == -1) {
189 udev_err(udev, "error getting socket: %m\n");
194 udev_monitor->bound = true;
195 udev_monitor->sock = fd;
198 udev_monitor->snl.nl.nl_family = AF_NETLINK;
199 udev_monitor->snl.nl.nl_groups = group;
201 /* default destination for sending */
202 udev_monitor->snl_destination.nl.nl_family = AF_NETLINK;
203 udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV;
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 _public_ 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 _public_ 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 memzero(ins, 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 >= ELEMENTSOF(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 memzero(&filter, sizeof(filter));
362 err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter));
363 return err < 0 ? -errno : 0;
366 int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender)
368 udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.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 _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
384 udev_monitor_filter_update(udev_monitor);
386 if (!udev_monitor->bound) {
387 err = bind(udev_monitor->sock,
388 &udev_monitor->snl.sa, sizeof(struct sockaddr_nl));
390 udev_monitor->bound = true;
394 union sockaddr_union snl;
398 * get the address the kernel has assigned us
399 * it is usually, but not necessarily the pid
401 addrlen = sizeof(struct sockaddr_nl);
402 err = getsockname(udev_monitor->sock, &snl.sa, &addrlen);
404 udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid;
406 udev_err(udev_monitor->udev, "bind failed: %m\n");
410 /* enable receiving of sender credentials */
411 setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
416 * udev_monitor_set_receive_buffer_size:
417 * @udev_monitor: the monitor which should receive events
418 * @size: the size in bytes
420 * Set the size of the kernel socket buffer. This call needs the
421 * appropriate privileges to succeed.
423 * Returns: 0 on success, otherwise -1 on error.
425 _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size)
427 if (udev_monitor == NULL)
429 return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size));
432 int udev_monitor_disconnect(struct udev_monitor *udev_monitor)
436 err = close(udev_monitor->sock);
437 udev_monitor->sock = -1;
438 return err < 0 ? -errno : 0;
443 * @udev_monitor: udev monitor
445 * Take a reference of a udev monitor.
447 * Returns: the passed udev monitor
449 _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
451 if (udev_monitor == NULL)
453 udev_monitor->refcount++;
458 * udev_monitor_unref:
459 * @udev_monitor: udev monitor
461 * Drop a reference of a udev monitor. If the refcount reaches zero,
462 * the bound socket will be closed, and the resources of the monitor
467 _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor)
469 if (udev_monitor == NULL)
471 udev_monitor->refcount--;
472 if (udev_monitor->refcount > 0)
474 if (udev_monitor->sock >= 0)
475 close(udev_monitor->sock);
476 udev_list_cleanup(&udev_monitor->filter_subsystem_list);
477 udev_list_cleanup(&udev_monitor->filter_tag_list);
483 * udev_monitor_get_udev:
484 * @udev_monitor: udev monitor
486 * Retrieve the udev library context the monitor was created with.
488 * Returns: the udev library context
490 _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
492 if (udev_monitor == NULL)
494 return udev_monitor->udev;
498 * udev_monitor_get_fd:
499 * @udev_monitor: udev monitor
501 * Retrieve the socket file descriptor associated with the monitor.
503 * Returns: the socket file descriptor
505 _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
507 if (udev_monitor == NULL)
509 return udev_monitor->sock;
512 static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device)
514 struct udev_list_entry *list_entry;
516 if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL)
518 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) {
519 const char *subsys = udev_list_entry_get_name(list_entry);
520 const char *dsubsys = udev_device_get_subsystem(udev_device);
522 const char *ddevtype;
524 if (!streq(dsubsys, subsys))
527 devtype = udev_list_entry_get_value(list_entry);
530 ddevtype = udev_device_get_devtype(udev_device);
531 if (ddevtype == NULL)
533 if (streq(ddevtype, devtype))
539 if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL)
541 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) {
542 const char *tag = udev_list_entry_get_name(list_entry);
544 if (udev_device_has_tag(udev_device, tag))
551 * udev_monitor_receive_device:
552 * @udev_monitor: udev monitor
554 * Receive data from the udev monitor socket, allocate a new udev
555 * device, fill in the received data, and return the device.
557 * Only socket connections with uid=0 are accepted.
559 * The monitor socket is by default set to NONBLOCK. A variant of poll() on
560 * the file descriptor returned by udev_monitor_get_fd() should to be used to
561 * wake up when new devices arrive, or alternatively the file descriptor
562 * switched into blocking mode.
564 * The initial refcount is 1, and needs to be decremented to
565 * release the resources of the udev device.
567 * Returns: a new udev device, or #NULL, in case of an error
569 _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
571 struct udev_device *udev_device;
574 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
575 struct cmsghdr *cmsg;
576 union sockaddr_union snl;
583 if (udev_monitor == NULL)
586 iov.iov_len = sizeof(buf);
587 memzero(&smsg, sizeof(struct msghdr));
590 smsg.msg_control = cred_msg;
591 smsg.msg_controllen = sizeof(cred_msg);
592 smsg.msg_name = &snl;
593 smsg.msg_namelen = sizeof(snl);
595 buflen = recvmsg(udev_monitor->sock, &smsg, 0);
598 udev_dbg(udev_monitor->udev, "unable to receive message\n");
602 if (buflen < 32 || (size_t)buflen >= sizeof(buf)) {
603 udev_dbg(udev_monitor->udev, "invalid message length\n");
607 if (snl.nl.nl_groups == 0) {
608 /* unicast message, check if we trust the sender */
609 if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 ||
610 snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) {
611 udev_dbg(udev_monitor->udev, "unicast netlink message ignored\n");
614 } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) {
615 if (snl.nl.nl_pid > 0) {
616 udev_dbg(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n",
622 cmsg = CMSG_FIRSTHDR(&smsg);
623 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
624 udev_dbg(udev_monitor->udev, "no sender credentials received, message ignored\n");
628 cred = (struct ucred *)CMSG_DATA(cmsg);
629 if (cred->uid != 0) {
630 udev_dbg(udev_monitor->udev, "sender uid=%d, message ignored\n", cred->uid);
634 udev_device = udev_device_new(udev_monitor->udev);
635 if (udev_device == NULL)
638 if (memcmp(buf, "libudev", 8) == 0) {
639 struct udev_monitor_netlink_header *nlh;
641 /* udev message needs proper version magic */
642 nlh = (struct udev_monitor_netlink_header *) buf;
643 if (nlh->magic != htonl(UDEV_MONITOR_MAGIC)) {
644 udev_err(udev_monitor->udev, "unrecognized message signature (%x != %x)\n",
645 nlh->magic, htonl(UDEV_MONITOR_MAGIC));
646 udev_device_unref(udev_device);
649 if (nlh->properties_off+32 > (size_t)buflen) {
650 udev_device_unref(udev_device);
654 bufpos = nlh->properties_off;
656 /* devices received from udev are always initialized */
657 udev_device_set_is_initialized(udev_device);
659 /* kernel message with header */
660 bufpos = strlen(buf) + 1;
661 if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) {
662 udev_dbg(udev_monitor->udev, "invalid message length\n");
663 udev_device_unref(udev_device);
667 /* check message header */
668 if (strstr(buf, "@/") == NULL) {
669 udev_dbg(udev_monitor->udev, "unrecognized message header\n");
670 udev_device_unref(udev_device);
675 udev_device_set_info_loaded(udev_device);
677 while (bufpos < buflen) {
682 keylen = strlen(key);
685 bufpos += keylen + 1;
686 udev_device_add_property_from_string_parse(udev_device, key);
689 if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) {
690 udev_dbg(udev_monitor->udev, "missing values, invalid device\n");
691 udev_device_unref(udev_device);
695 /* skip device, if it does not pass the current filter */
696 if (!passes_filter(udev_monitor, udev_device)) {
697 struct pollfd pfd[1];
700 udev_device_unref(udev_device);
702 /* if something is queued, get next device */
703 pfd[0].fd = udev_monitor->sock;
704 pfd[0].events = POLLIN;
705 rc = poll(pfd, 1, 0);
714 int udev_monitor_send_device(struct udev_monitor *udev_monitor,
715 struct udev_monitor *destination, struct udev_device *udev_device)
723 struct udev_monitor_netlink_header nlh;
724 struct udev_list_entry *list_entry;
725 uint64_t tag_bloom_bits;
727 blen = udev_device_get_properties_monitor_buf(udev_device, &buf);
731 /* add versioned header */
732 memzero(&nlh, sizeof(struct udev_monitor_netlink_header));
733 memcpy(nlh.prefix, "libudev", 8);
734 nlh.magic = htonl(UDEV_MONITOR_MAGIC);
735 nlh.header_size = sizeof(struct udev_monitor_netlink_header);
736 val = udev_device_get_subsystem(udev_device);
737 nlh.filter_subsystem_hash = htonl(util_string_hash32(val));
738 val = udev_device_get_devtype(udev_device);
740 nlh.filter_devtype_hash = htonl(util_string_hash32(val));
741 iov[0].iov_base = &nlh;
742 iov[0].iov_len = sizeof(struct udev_monitor_netlink_header);
744 /* add tag bloom filter */
746 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
747 tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry));
748 if (tag_bloom_bits > 0) {
749 nlh.filter_tag_bloom_hi = htonl(tag_bloom_bits >> 32);
750 nlh.filter_tag_bloom_lo = htonl(tag_bloom_bits & 0xffffffff);
753 /* add properties list */
754 nlh.properties_off = iov[0].iov_len;
755 nlh.properties_len = blen;
756 iov[1].iov_base = (char *)buf;
757 iov[1].iov_len = blen;
759 memzero(&smsg, sizeof(struct msghdr));
763 * Use custom address for target, or the default one.
765 * If we send to a multicast group, we will get
766 * ECONNREFUSED, which is expected.
768 if (destination != NULL)
769 smsg.msg_name = &destination->snl;
771 smsg.msg_name = &udev_monitor->snl_destination;
772 smsg.msg_namelen = sizeof(struct sockaddr_nl);
773 count = sendmsg(udev_monitor->sock, &smsg, 0);
774 udev_dbg(udev_monitor->udev, "passed %zi bytes to netlink monitor %p\n", count, udev_monitor);
779 * udev_monitor_filter_add_match_subsystem_devtype:
780 * @udev_monitor: the monitor
781 * @subsystem: the subsystem value to match the incoming devices against
782 * @devtype: the devtype value to match the incoming devices against
784 * This filter is efficiently executed inside the kernel, and libudev subscribers
785 * will usually not be woken up for devices which do not match.
787 * The filter must be installed before the monitor is switched to listening mode.
789 * Returns: 0 on success, otherwise a negative error value.
791 _public_ int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype)
793 if (udev_monitor == NULL)
795 if (subsystem == NULL)
797 if (udev_list_entry_add(&udev_monitor->filter_subsystem_list, subsystem, devtype) == NULL)
803 * udev_monitor_filter_add_match_tag:
804 * @udev_monitor: the monitor
805 * @tag: the name of a tag
807 * This filter is efficiently executed inside the kernel, and libudev subscribers
808 * will usually not be woken up for devices which do not match.
810 * The filter must be installed before the monitor is switched to listening mode.
812 * Returns: 0 on success, otherwise a negative error value.
814 _public_ int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag)
816 if (udev_monitor == NULL)
820 if (udev_list_entry_add(&udev_monitor->filter_tag_list, tag, NULL) == NULL)
826 * udev_monitor_filter_remove:
827 * @udev_monitor: monitor
829 * Remove all filters from monitor.
831 * Returns: 0 on success, otherwise a negative error value.
833 _public_ int udev_monitor_filter_remove(struct udev_monitor *udev_monitor)
835 static struct sock_fprog filter = { 0, NULL };
837 udev_list_cleanup(&udev_monitor->filter_subsystem_list);
838 return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter));