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
) {
112 union file_handle_union h
= {
113 .handle
.handle_bytes
= MAX_HANDLE_SZ
116 _cleanup_fclose_
FILE *f
= NULL
;
117 char line
[LINE_MAX
], *e
;
121 r
= name_to_handle_at(AT_FDCWD
, "/dev", &h
.handle
, &mount_id
, 0);
123 if (errno
!= EOPNOTSUPP
)
124 udev_dbg(udev
, "name_to_handle_at on /dev: %m\n");
128 f
= fopen("/proc/self/mountinfo", "re");
132 FOREACH_LINE(line
, f
, return false) {
135 if (sscanf(line
, "%i", &mid
) != 1)
141 e
= strstr(line
, " - ");
145 /* accept any name that starts with the currently expected type */
146 if (startswith(e
+ 3, "devtmpfs"))
153 struct udev_monitor
*udev_monitor_new_from_netlink_fd(struct udev
*udev
, const char *name
, int fd
)
155 struct udev_monitor
*udev_monitor
;
162 group
= UDEV_MONITOR_NONE
;
163 else if (streq(name
, "udev")) {
165 * We do not support subscribing to uevents if no instance of
166 * udev is running. Uevents would otherwise broadcast the
167 * processing data of the host into containers, which is not
170 * Containers will currently not get any udev uevents, until
171 * a supporting infrastructure is available.
173 * We do not set a netlink multicast group here, so the socket
174 * will not receive any messages.
176 if (access("/run/udev/control", F_OK
) < 0 && !udev_has_devtmpfs(udev
)) {
177 udev_dbg(udev
, "the udev service seems not to be active, disable the monitor\n");
178 group
= UDEV_MONITOR_NONE
;
180 group
= UDEV_MONITOR_UDEV
;
181 } else if (streq(name
, "kernel"))
182 group
= UDEV_MONITOR_KERNEL
;
186 udev_monitor
= udev_monitor_new(udev
);
187 if (udev_monitor
== NULL
)
191 udev_monitor
->sock
= socket(PF_NETLINK
, SOCK_RAW
|SOCK_CLOEXEC
|SOCK_NONBLOCK
, NETLINK_KOBJECT_UEVENT
);
192 if (udev_monitor
->sock
== -1) {
193 udev_dbg(udev
, "error getting socket: %m\n");
198 udev_monitor
->bound
= true;
199 udev_monitor
->sock
= fd
;
202 udev_monitor
->snl
.nl
.nl_family
= AF_NETLINK
;
203 udev_monitor
->snl
.nl
.nl_groups
= group
;
205 /* default destination for sending */
206 udev_monitor
->snl_destination
.nl
.nl_family
= AF_NETLINK
;
207 udev_monitor
->snl_destination
.nl
.nl_groups
= UDEV_MONITOR_UDEV
;
213 * udev_monitor_new_from_netlink:
214 * @udev: udev library context
215 * @name: name of event source
217 * Create new udev monitor and connect to a specified event
218 * source. Valid sources identifiers are "udev" and "kernel".
220 * Applications should usually not connect directly to the
221 * "kernel" events, because the devices might not be useable
222 * at that time, before udev has configured them, and created
223 * device nodes. Accessing devices at the same time as udev,
224 * might result in unpredictable behavior. The "udev" events
225 * are sent out after udev has finished its event processing,
226 * all rules have been processed, and needed device nodes are
229 * The initial refcount is 1, and needs to be decremented to
230 * release the resources of the udev monitor.
232 * Returns: a new udev monitor, or #NULL, in case of an error
234 _public_
struct udev_monitor
*udev_monitor_new_from_netlink(struct udev
*udev
, const char *name
)
236 return udev_monitor_new_from_netlink_fd(udev
, name
, -1);
239 static inline void bpf_stmt(struct sock_filter
*inss
, unsigned int *i
,
240 unsigned short code
, unsigned int data
)
242 struct sock_filter
*ins
= &inss
[*i
];
249 static inline void bpf_jmp(struct sock_filter
*inss
, unsigned int *i
,
250 unsigned short code
, unsigned int data
,
251 unsigned short jt
, unsigned short jf
)
253 struct sock_filter
*ins
= &inss
[*i
];
263 * udev_monitor_filter_update:
264 * @udev_monitor: monitor
266 * Update the installed socket filter. This is only needed,
267 * if the filter was removed or changed.
269 * Returns: 0 on success, otherwise a negative error value.
271 _public_
int udev_monitor_filter_update(struct udev_monitor
*udev_monitor
)
273 struct sock_filter ins
[512];
274 struct sock_fprog filter
;
276 struct udev_list_entry
*list_entry
;
279 if (udev_list_get_entry(&udev_monitor
->filter_subsystem_list
) == NULL
&&
280 udev_list_get_entry(&udev_monitor
->filter_tag_list
) == NULL
)
283 memzero(ins
, sizeof(ins
));
286 /* load magic in A */
287 bpf_stmt(ins
, &i
, BPF_LD
|BPF_W
|BPF_ABS
, offsetof(struct udev_monitor_netlink_header
, magic
));
288 /* jump if magic matches */
289 bpf_jmp(ins
, &i
, BPF_JMP
|BPF_JEQ
|BPF_K
, UDEV_MONITOR_MAGIC
, 1, 0);
290 /* wrong magic, pass packet */
291 bpf_stmt(ins
, &i
, BPF_RET
|BPF_K
, 0xffffffff);
293 if (udev_list_get_entry(&udev_monitor
->filter_tag_list
) != NULL
) {
296 /* count tag matches, to calculate end of tag match block */
298 udev_list_entry_foreach(list_entry
, udev_list_get_entry(&udev_monitor
->filter_tag_list
))
301 /* add all tags matches */
302 udev_list_entry_foreach(list_entry
, udev_list_get_entry(&udev_monitor
->filter_tag_list
)) {
303 uint64_t tag_bloom_bits
= util_string_bloom64(udev_list_entry_get_name(list_entry
));
304 uint32_t tag_bloom_hi
= tag_bloom_bits
>> 32;
305 uint32_t tag_bloom_lo
= tag_bloom_bits
& 0xffffffff;
307 /* load device bloom bits in A */
308 bpf_stmt(ins
, &i
, BPF_LD
|BPF_W
|BPF_ABS
, offsetof(struct udev_monitor_netlink_header
, filter_tag_bloom_hi
));
309 /* clear bits (tag bits & bloom bits) */
310 bpf_stmt(ins
, &i
, BPF_ALU
|BPF_AND
|BPF_K
, tag_bloom_hi
);
311 /* jump to next tag if it does not match */
312 bpf_jmp(ins
, &i
, BPF_JMP
|BPF_JEQ
|BPF_K
, tag_bloom_hi
, 0, 3);
314 /* load device bloom bits in A */
315 bpf_stmt(ins
, &i
, BPF_LD
|BPF_W
|BPF_ABS
, offsetof(struct udev_monitor_netlink_header
, filter_tag_bloom_lo
));
316 /* clear bits (tag bits & bloom bits) */
317 bpf_stmt(ins
, &i
, BPF_ALU
|BPF_AND
|BPF_K
, tag_bloom_lo
);
318 /* jump behind end of tag match block if tag matches */
320 bpf_jmp(ins
, &i
, BPF_JMP
|BPF_JEQ
|BPF_K
, tag_bloom_lo
, 1 + (tag_matches
* 6), 0);
323 /* nothing matched, drop packet */
324 bpf_stmt(ins
, &i
, BPF_RET
|BPF_K
, 0);
327 /* add all subsystem matches */
328 if (udev_list_get_entry(&udev_monitor
->filter_subsystem_list
) != NULL
) {
329 udev_list_entry_foreach(list_entry
, udev_list_get_entry(&udev_monitor
->filter_subsystem_list
)) {
330 unsigned int hash
= util_string_hash32(udev_list_entry_get_name(list_entry
));
332 /* load device subsystem value in A */
333 bpf_stmt(ins
, &i
, BPF_LD
|BPF_W
|BPF_ABS
, offsetof(struct udev_monitor_netlink_header
, filter_subsystem_hash
));
334 if (udev_list_entry_get_value(list_entry
) == NULL
) {
335 /* jump if subsystem does not match */
336 bpf_jmp(ins
, &i
, BPF_JMP
|BPF_JEQ
|BPF_K
, hash
, 0, 1);
338 /* jump if subsystem does not match */
339 bpf_jmp(ins
, &i
, BPF_JMP
|BPF_JEQ
|BPF_K
, hash
, 0, 3);
341 /* load device devtype value in A */
342 bpf_stmt(ins
, &i
, BPF_LD
|BPF_W
|BPF_ABS
, offsetof(struct udev_monitor_netlink_header
, filter_devtype_hash
));
343 /* jump if value does not match */
344 hash
= util_string_hash32(udev_list_entry_get_value(list_entry
));
345 bpf_jmp(ins
, &i
, BPF_JMP
|BPF_JEQ
|BPF_K
, hash
, 0, 1);
348 /* matched, pass packet */
349 bpf_stmt(ins
, &i
, BPF_RET
|BPF_K
, 0xffffffff);
351 if (i
+1 >= ELEMENTSOF(ins
))
355 /* nothing matched, drop packet */
356 bpf_stmt(ins
, &i
, BPF_RET
|BPF_K
, 0);
359 /* matched, pass packet */
360 bpf_stmt(ins
, &i
, BPF_RET
|BPF_K
, 0xffffffff);
363 memzero(&filter
, sizeof(filter
));
366 err
= setsockopt(udev_monitor
->sock
, SOL_SOCKET
, SO_ATTACH_FILTER
, &filter
, sizeof(filter
));
367 return err
< 0 ? -errno
: 0;
370 int udev_monitor_allow_unicast_sender(struct udev_monitor
*udev_monitor
, struct udev_monitor
*sender
)
372 udev_monitor
->snl_trusted_sender
.nl
.nl_pid
= sender
->snl
.nl
.nl_pid
;
376 * udev_monitor_enable_receiving:
377 * @udev_monitor: the monitor which should receive events
379 * Binds the @udev_monitor socket to the event source.
381 * Returns: 0 on success, otherwise a negative error value.
383 _public_
int udev_monitor_enable_receiving(struct udev_monitor
*udev_monitor
)
388 udev_monitor_filter_update(udev_monitor
);
390 if (!udev_monitor
->bound
) {
391 err
= bind(udev_monitor
->sock
,
392 &udev_monitor
->snl
.sa
, sizeof(struct sockaddr_nl
));
394 udev_monitor
->bound
= true;
398 union sockaddr_union snl
;
402 * get the address the kernel has assigned us
403 * it is usually, but not necessarily the pid
405 addrlen
= sizeof(struct sockaddr_nl
);
406 err
= getsockname(udev_monitor
->sock
, &snl
.sa
, &addrlen
);
408 udev_monitor
->snl
.nl
.nl_pid
= snl
.nl
.nl_pid
;
410 udev_dbg(udev_monitor
->udev
, "bind failed: %m\n");
414 /* enable receiving of sender credentials */
415 err
= setsockopt(udev_monitor
->sock
, SOL_SOCKET
, SO_PASSCRED
, &on
, sizeof(on
));
417 udev_dbg(udev_monitor
->udev
, "setting SO_PASSCRED failed: %m\n");
423 * udev_monitor_set_receive_buffer_size:
424 * @udev_monitor: the monitor which should receive events
425 * @size: the size in bytes
427 * Set the size of the kernel socket buffer. This call needs the
428 * appropriate privileges to succeed.
430 * Returns: 0 on success, otherwise -1 on error.
432 _public_
int udev_monitor_set_receive_buffer_size(struct udev_monitor
*udev_monitor
, int size
)
434 if (udev_monitor
== NULL
)
436 return setsockopt(udev_monitor
->sock
, SOL_SOCKET
, SO_RCVBUFFORCE
, &size
, sizeof(size
));
439 int udev_monitor_disconnect(struct udev_monitor
*udev_monitor
)
443 err
= close(udev_monitor
->sock
);
444 udev_monitor
->sock
= -1;
445 return err
< 0 ? -errno
: 0;
450 * @udev_monitor: udev monitor
452 * Take a reference of a udev monitor.
454 * Returns: the passed udev monitor
456 _public_
struct udev_monitor
*udev_monitor_ref(struct udev_monitor
*udev_monitor
)
458 if (udev_monitor
== NULL
)
460 udev_monitor
->refcount
++;
465 * udev_monitor_unref:
466 * @udev_monitor: udev monitor
468 * Drop a reference of a udev monitor. If the refcount reaches zero,
469 * the bound socket will be closed, and the resources of the monitor
474 _public_
struct udev_monitor
*udev_monitor_unref(struct udev_monitor
*udev_monitor
)
476 if (udev_monitor
== NULL
)
478 udev_monitor
->refcount
--;
479 if (udev_monitor
->refcount
> 0)
481 if (udev_monitor
->sock
>= 0)
482 close(udev_monitor
->sock
);
483 udev_list_cleanup(&udev_monitor
->filter_subsystem_list
);
484 udev_list_cleanup(&udev_monitor
->filter_tag_list
);
490 * udev_monitor_get_udev:
491 * @udev_monitor: udev monitor
493 * Retrieve the udev library context the monitor was created with.
495 * Returns: the udev library context
497 _public_
struct udev
*udev_monitor_get_udev(struct udev_monitor
*udev_monitor
)
499 if (udev_monitor
== NULL
)
501 return udev_monitor
->udev
;
505 * udev_monitor_get_fd:
506 * @udev_monitor: udev monitor
508 * Retrieve the socket file descriptor associated with the monitor.
510 * Returns: the socket file descriptor
512 _public_
int udev_monitor_get_fd(struct udev_monitor
*udev_monitor
)
514 if (udev_monitor
== NULL
)
516 return udev_monitor
->sock
;
519 static int passes_filter(struct udev_monitor
*udev_monitor
, struct udev_device
*udev_device
)
521 struct udev_list_entry
*list_entry
;
523 if (udev_list_get_entry(&udev_monitor
->filter_subsystem_list
) == NULL
)
525 udev_list_entry_foreach(list_entry
, udev_list_get_entry(&udev_monitor
->filter_subsystem_list
)) {
526 const char *subsys
= udev_list_entry_get_name(list_entry
);
527 const char *dsubsys
= udev_device_get_subsystem(udev_device
);
529 const char *ddevtype
;
531 if (!streq(dsubsys
, subsys
))
534 devtype
= udev_list_entry_get_value(list_entry
);
537 ddevtype
= udev_device_get_devtype(udev_device
);
538 if (ddevtype
== NULL
)
540 if (streq(ddevtype
, devtype
))
546 if (udev_list_get_entry(&udev_monitor
->filter_tag_list
) == NULL
)
548 udev_list_entry_foreach(list_entry
, udev_list_get_entry(&udev_monitor
->filter_tag_list
)) {
549 const char *tag
= udev_list_entry_get_name(list_entry
);
551 if (udev_device_has_tag(udev_device
, tag
))
558 * udev_monitor_receive_device:
559 * @udev_monitor: udev monitor
561 * Receive data from the udev monitor socket, allocate a new udev
562 * device, fill in the received data, and return the device.
564 * Only socket connections with uid=0 are accepted.
566 * The monitor socket is by default set to NONBLOCK. A variant of poll() on
567 * the file descriptor returned by udev_monitor_get_fd() should to be used to
568 * wake up when new devices arrive, or alternatively the file descriptor
569 * switched into blocking mode.
571 * The initial refcount is 1, and needs to be decremented to
572 * release the resources of the udev device.
574 * Returns: a new udev device, or #NULL, in case of an error
576 _public_
struct udev_device
*udev_monitor_receive_device(struct udev_monitor
*udev_monitor
)
578 struct udev_device
*udev_device
;
581 char cred_msg
[CMSG_SPACE(sizeof(struct ucred
))];
582 struct cmsghdr
*cmsg
;
583 union sockaddr_union snl
;
590 if (udev_monitor
== NULL
)
593 iov
.iov_len
= sizeof(buf
);
594 memzero(&smsg
, sizeof(struct msghdr
));
597 smsg
.msg_control
= cred_msg
;
598 smsg
.msg_controllen
= sizeof(cred_msg
);
599 smsg
.msg_name
= &snl
;
600 smsg
.msg_namelen
= sizeof(snl
);
602 buflen
= recvmsg(udev_monitor
->sock
, &smsg
, 0);
605 udev_dbg(udev_monitor
->udev
, "unable to receive message\n");
609 if (buflen
< 32 || (size_t)buflen
>= sizeof(buf
)) {
610 udev_dbg(udev_monitor
->udev
, "invalid message length\n");
614 if (snl
.nl
.nl_groups
== 0) {
615 /* unicast message, check if we trust the sender */
616 if (udev_monitor
->snl_trusted_sender
.nl
.nl_pid
== 0 ||
617 snl
.nl
.nl_pid
!= udev_monitor
->snl_trusted_sender
.nl
.nl_pid
) {
618 udev_dbg(udev_monitor
->udev
, "unicast netlink message ignored\n");
621 } else if (snl
.nl
.nl_groups
== UDEV_MONITOR_KERNEL
) {
622 if (snl
.nl
.nl_pid
> 0) {
623 udev_dbg(udev_monitor
->udev
, "multicast kernel netlink message from pid %d ignored\n",
629 cmsg
= CMSG_FIRSTHDR(&smsg
);
630 if (cmsg
== NULL
|| cmsg
->cmsg_type
!= SCM_CREDENTIALS
) {
631 udev_dbg(udev_monitor
->udev
, "no sender credentials received, message ignored\n");
635 cred
= (struct ucred
*)CMSG_DATA(cmsg
);
636 if (cred
->uid
!= 0) {
637 udev_dbg(udev_monitor
->udev
, "sender uid=%d, message ignored\n", cred
->uid
);
641 udev_device
= udev_device_new(udev_monitor
->udev
);
642 if (udev_device
== NULL
)
645 if (memcmp(buf
, "libudev", 8) == 0) {
646 struct udev_monitor_netlink_header
*nlh
;
648 /* udev message needs proper version magic */
649 nlh
= (struct udev_monitor_netlink_header
*) buf
;
650 if (nlh
->magic
!= htonl(UDEV_MONITOR_MAGIC
)) {
651 udev_dbg(udev_monitor
->udev
, "unrecognized message signature (%x != %x)\n",
652 nlh
->magic
, htonl(UDEV_MONITOR_MAGIC
));
653 udev_device_unref(udev_device
);
656 if (nlh
->properties_off
+32 > (size_t)buflen
) {
657 udev_device_unref(udev_device
);
661 bufpos
= nlh
->properties_off
;
663 /* devices received from udev are always initialized */
664 udev_device_set_is_initialized(udev_device
);
666 /* kernel message with header */
667 bufpos
= strlen(buf
) + 1;
668 if ((size_t)bufpos
< sizeof("a@/d") || bufpos
>= buflen
) {
669 udev_dbg(udev_monitor
->udev
, "invalid message length\n");
670 udev_device_unref(udev_device
);
674 /* check message header */
675 if (strstr(buf
, "@/") == NULL
) {
676 udev_dbg(udev_monitor
->udev
, "unrecognized message header\n");
677 udev_device_unref(udev_device
);
682 udev_device_set_info_loaded(udev_device
);
684 while (bufpos
< buflen
) {
689 keylen
= strlen(key
);
692 bufpos
+= keylen
+ 1;
693 udev_device_add_property_from_string_parse(udev_device
, key
);
696 if (udev_device_add_property_from_string_parse_finish(udev_device
) < 0) {
697 udev_dbg(udev_monitor
->udev
, "missing values, invalid device\n");
698 udev_device_unref(udev_device
);
702 /* skip device, if it does not pass the current filter */
703 if (!passes_filter(udev_monitor
, udev_device
)) {
704 struct pollfd pfd
[1];
707 udev_device_unref(udev_device
);
709 /* if something is queued, get next device */
710 pfd
[0].fd
= udev_monitor
->sock
;
711 pfd
[0].events
= POLLIN
;
712 rc
= poll(pfd
, 1, 0);
721 int udev_monitor_send_device(struct udev_monitor
*udev_monitor
,
722 struct udev_monitor
*destination
, struct udev_device
*udev_device
)
730 struct udev_monitor_netlink_header nlh
;
731 struct udev_list_entry
*list_entry
;
732 uint64_t tag_bloom_bits
;
734 blen
= udev_device_get_properties_monitor_buf(udev_device
, &buf
);
738 /* add versioned header */
739 memzero(&nlh
, sizeof(struct udev_monitor_netlink_header
));
740 memcpy(nlh
.prefix
, "libudev", 8);
741 nlh
.magic
= htonl(UDEV_MONITOR_MAGIC
);
742 nlh
.header_size
= sizeof(struct udev_monitor_netlink_header
);
743 val
= udev_device_get_subsystem(udev_device
);
744 nlh
.filter_subsystem_hash
= htonl(util_string_hash32(val
));
745 val
= udev_device_get_devtype(udev_device
);
747 nlh
.filter_devtype_hash
= htonl(util_string_hash32(val
));
748 iov
[0].iov_base
= &nlh
;
749 iov
[0].iov_len
= sizeof(struct udev_monitor_netlink_header
);
751 /* add tag bloom filter */
753 udev_list_entry_foreach(list_entry
, udev_device_get_tags_list_entry(udev_device
))
754 tag_bloom_bits
|= util_string_bloom64(udev_list_entry_get_name(list_entry
));
755 if (tag_bloom_bits
> 0) {
756 nlh
.filter_tag_bloom_hi
= htonl(tag_bloom_bits
>> 32);
757 nlh
.filter_tag_bloom_lo
= htonl(tag_bloom_bits
& 0xffffffff);
760 /* add properties list */
761 nlh
.properties_off
= iov
[0].iov_len
;
762 nlh
.properties_len
= blen
;
763 iov
[1].iov_base
= (char *)buf
;
764 iov
[1].iov_len
= blen
;
766 memzero(&smsg
, sizeof(struct msghdr
));
770 * Use custom address for target, or the default one.
772 * If we send to a multicast group, we will get
773 * ECONNREFUSED, which is expected.
775 if (destination
!= NULL
)
776 smsg
.msg_name
= &destination
->snl
;
778 smsg
.msg_name
= &udev_monitor
->snl_destination
;
779 smsg
.msg_namelen
= sizeof(struct sockaddr_nl
);
780 count
= sendmsg(udev_monitor
->sock
, &smsg
, 0);
781 udev_dbg(udev_monitor
->udev
, "passed %zi bytes to netlink monitor %p\n", count
, udev_monitor
);
786 * udev_monitor_filter_add_match_subsystem_devtype:
787 * @udev_monitor: the monitor
788 * @subsystem: the subsystem value to match the incoming devices against
789 * @devtype: the devtype value to match the incoming devices against
791 * This filter is efficiently executed inside the kernel, and libudev subscribers
792 * will usually not be woken up for devices which do not match.
794 * The filter must be installed before the monitor is switched to listening mode.
796 * Returns: 0 on success, otherwise a negative error value.
798 _public_
int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor
*udev_monitor
, const char *subsystem
, const char *devtype
)
800 if (udev_monitor
== NULL
)
802 if (subsystem
== NULL
)
804 if (udev_list_entry_add(&udev_monitor
->filter_subsystem_list
, subsystem
, devtype
) == NULL
)
810 * udev_monitor_filter_add_match_tag:
811 * @udev_monitor: the monitor
812 * @tag: the name of a tag
814 * This filter is efficiently executed inside the kernel, and libudev subscribers
815 * will usually not be woken up for devices which do not match.
817 * The filter must be installed before the monitor is switched to listening mode.
819 * Returns: 0 on success, otherwise a negative error value.
821 _public_
int udev_monitor_filter_add_match_tag(struct udev_monitor
*udev_monitor
, const char *tag
)
823 if (udev_monitor
== NULL
)
827 if (udev_list_entry_add(&udev_monitor
->filter_tag_list
, tag
, NULL
) == NULL
)
833 * udev_monitor_filter_remove:
834 * @udev_monitor: monitor
836 * Remove all filters from monitor.
838 * Returns: 0 on success, otherwise a negative error value.
840 _public_
int udev_monitor_filter_remove(struct udev_monitor
*udev_monitor
)
842 static struct sock_fprog filter
= { 0, NULL
};
844 udev_list_cleanup(&udev_monitor
->filter_subsystem_list
);
845 return setsockopt(udev_monitor
->sock
, SOL_SOCKET
, SO_ATTACH_FILTER
, &filter
, sizeof(filter
));