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|
/*
* libudev - interface to udev device information
*
* Copyright (C) 2008-2010 Kay Sievers <kay.sievers@vrfy.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <dirent.h>
#include <sys/poll.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <arpa/inet.h>
#include <linux/netlink.h>
#include <linux/filter.h>
#include "libudev.h"
#include "libudev-private.h"
/**
* SECTION:libudev-monitor
* @short_description: device event source
*
* Connects to a device event source.
*/
/**
* udev_monitor:
*
* Opaque object handling one event source.
*/
struct udev_monitor {
struct udev *udev;
int refcount;
int sock;
struct sockaddr_nl snl;
struct sockaddr_nl snl_trusted_sender;
struct sockaddr_nl snl_destination;
struct sockaddr_un sun;
socklen_t addrlen;
struct udev_list_node filter_subsystem_list;
struct udev_list_node filter_tag_list;
};
enum udev_monitor_netlink_group {
UDEV_MONITOR_NONE,
UDEV_MONITOR_KERNEL,
UDEV_MONITOR_UDEV,
};
#define UDEV_MONITOR_MAGIC 0xfeedcafe
struct udev_monitor_netlink_header {
/* "libudev" prefix to distinguish libudev and kernel messages */
char prefix[8];
/*
* magic to protect against daemon <-> library message format mismatch
* used in the kernel from socket filter rules; needs to be stored in network order
*/
unsigned int magic;
/* total length of header structure known to the sender */
unsigned int header_size;
/* properties string buffer */
unsigned int properties_off;
unsigned int properties_len;
/*
* hashes of primary device properties strings, to let libudev subscribers
* use in-kernel socket filters; values need to be stored in network order
*/
unsigned int filter_subsystem_hash;
unsigned int filter_devtype_hash;
unsigned int filter_tag_bloom_hi;
unsigned int filter_tag_bloom_lo;
};
static struct udev_monitor *udev_monitor_new(struct udev *udev)
{
struct udev_monitor *udev_monitor;
udev_monitor = calloc(1, sizeof(struct udev_monitor));
if (udev_monitor == NULL)
return NULL;
udev_monitor->refcount = 1;
udev_monitor->udev = udev;
udev_list_init(&udev_monitor->filter_subsystem_list);
udev_list_init(&udev_monitor->filter_tag_list);
return udev_monitor;
}
/**
* udev_monitor_new_from_socket:
* @udev: udev library context
* @socket_path: unix socket path
*
* Create new udev monitor and connect to a specified socket. The
* path to a socket either points to an existing socket file, or if
* the socket path starts with a '@' character, an abstract namespace
* socket will be used.
*
* A socket file will not be created. If it does not already exist,
* it will fall-back and connect to an abstract namespace socket with
* the given path. The permissions adjustment of a socket file, as
* well as the later cleanup, needs to be done by the caller.
*
* The initial refcount is 1, and needs to be decremented to
* release the resources of the udev monitor.
*
* Returns: a new udev monitor, or #NULL, in case of an error
**/
struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path)
{
struct udev_monitor *udev_monitor;
struct stat statbuf;
if (udev == NULL)
return NULL;
if (socket_path == NULL)
return NULL;
udev_monitor = udev_monitor_new(udev);
if (udev_monitor == NULL)
return NULL;
udev_monitor->sun.sun_family = AF_LOCAL;
if (socket_path[0] == '@') {
/* translate leading '@' to abstract namespace */
util_strscpy(udev_monitor->sun.sun_path, sizeof(udev_monitor->sun.sun_path), socket_path);
udev_monitor->sun.sun_path[0] = '\0';
udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path);
} else if (stat(socket_path, &statbuf) == 0 && S_ISSOCK(statbuf.st_mode)) {
/* existing socket file */
util_strscpy(udev_monitor->sun.sun_path, sizeof(udev_monitor->sun.sun_path), socket_path);
udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path);
} else {
/* no socket file, assume abstract namespace socket */
util_strscpy(&udev_monitor->sun.sun_path[1], sizeof(udev_monitor->sun.sun_path)-1, socket_path);
udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path)+1;
}
udev_monitor->sock = socket(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0);
if (udev_monitor->sock == -1) {
err(udev, "error getting socket: %m\n");
free(udev_monitor);
return NULL;
}
dbg(udev, "monitor %p created with '%s'\n", udev_monitor, socket_path);
return udev_monitor;
}
/**
* udev_monitor_new_from_netlink:
* @udev: udev library context
* @name: name of event source
*
* Create new udev monitor and connect to a specified event
* source. Valid sources identifiers are "udev" and "kernel".
*
* Applications should usually not connect directly to the
* "kernel" events, because the devices might not be useable
* at that time, before udev has configured them, and created
* device nodes.
*
* Accessing devices at the same time as udev, might result
* in unpredictable behavior.
*
* The "udev" events are sent out after udev has finished its
* event processing, all rules have been processed, and needed
* device nodes are created.
*
* The initial refcount is 1, and needs to be decremented to
* release the resources of the udev monitor.
*
* Returns: a new udev monitor, or #NULL, in case of an error
**/
struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name)
{
struct udev_monitor *udev_monitor;
unsigned int group;
if (udev == NULL)
return NULL;
if (name == NULL)
group = UDEV_MONITOR_NONE;
else if (strcmp(name, "udev") == 0)
group = UDEV_MONITOR_UDEV;
else if (strcmp(name, "kernel") == 0)
group = UDEV_MONITOR_KERNEL;
else
return NULL;
udev_monitor = udev_monitor_new(udev);
if (udev_monitor == NULL)
return NULL;
udev_monitor->sock = socket(PF_NETLINK, SOCK_DGRAM|SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT);
if (udev_monitor->sock == -1) {
err(udev, "error getting socket: %m\n");
free(udev_monitor);
return NULL;
}
udev_monitor->snl.nl_family = AF_NETLINK;
udev_monitor->snl.nl_groups = group;
/* default destination for sending */
udev_monitor->snl_destination.nl_family = AF_NETLINK;
udev_monitor->snl_destination.nl_groups = UDEV_MONITOR_UDEV;
dbg(udev, "monitor %p created with NETLINK_KOBJECT_UEVENT (%u)\n", udev_monitor, group);
return udev_monitor;
}
static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i,
unsigned short code, unsigned int data)
{
struct sock_filter *ins = &inss[*i];
ins->code = code;
ins->k = data;
(*i)++;
}
static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i,
unsigned short code, unsigned int data,
unsigned short jt, unsigned short jf)
{
struct sock_filter *ins = &inss[*i];
ins->code = code;
ins->jt = jt;
ins->jf = jf;
ins->k = data;
(*i)++;
}
/**
* udev_monitor_filter_update:
* @udev_monitor: monitor
*
* Update the installed filter. This might only be needed, if the filter was removed or changed.
*
* Returns: 0 on success, otherwise a negative error value.
*/
int udev_monitor_filter_update(struct udev_monitor *udev_monitor)
{
struct sock_filter ins[512];
struct sock_fprog filter;
unsigned int i;
struct udev_list_entry *list_entry;
int err;
if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL &&
udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL)
return 0;
memset(ins, 0x00, sizeof(ins));
i = 0;
/* load magic in A */
bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic));
/* jump if magic matches */
bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0);
/* wrong magic, pass packet */
bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) {
int tag_matches;
/* count tag matches, to calculate end of tag match block */
tag_matches = 0;
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list))
tag_matches++;
/* add all tags matches */
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) {
uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry));
uint32_t tag_bloom_hi = tag_bloom_bits >> 32;
uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff;
/* load device bloom bits in A */
bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi));
/* clear bits (tag bits & bloom bits) */
bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi);
/* jump to next tag if it does not match */
bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3);
/* load device bloom bits in A */
bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo));
/* clear bits (tag bits & bloom bits) */
bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo);
/* jump behind end of tag match block if tag matches */
tag_matches--;
bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0);
}
/* nothing matched, drop packet */
bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
}
/* add all subsystem matches */
if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) {
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) {
unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry));
/* load device subsystem value in A */
bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash));
if (udev_list_entry_get_value(list_entry) == NULL) {
/* jump if subsystem does not match */
bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1);
} else {
/* jump if subsystem does not match */
bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3);
/* load device devtype value in A */
bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash));
/* jump if value does not match */
hash = util_string_hash32(udev_list_entry_get_value(list_entry));
bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1);
}
/* matched, pass packet */
bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
if (i+1 >= ARRAY_SIZE(ins))
return -1;
}
/* nothing matched, drop packet */
bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
}
/* matched, pass packet */
bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
/* install filter */
memset(&filter, 0x00, sizeof(filter));
filter.len = i;
filter.filter = ins;
err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter));
return err;
}
int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender)
{
udev_monitor->snl_trusted_sender.nl_pid = sender->snl.nl_pid;
return 0;
}
/**
* udev_monitor_enable_receiving:
* @udev_monitor: the monitor which should receive events
*
* Binds the @udev_monitor socket to the event source.
*
* Returns: 0 on success, otherwise a negative error value.
*/
int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
{
int err;
const int on = 1;
if (udev_monitor->sun.sun_family != 0) {
err = bind(udev_monitor->sock,
(struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
} else if (udev_monitor->snl.nl_family != 0) {
udev_monitor_filter_update(udev_monitor);
err = bind(udev_monitor->sock,
(struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
if (err == 0) {
struct sockaddr_nl snl;
socklen_t addrlen;
/*
* get the address the kernel has assigned us
* it is usually, but not necessarily the pid
*/
addrlen = sizeof(struct sockaddr_nl);
err = getsockname(udev_monitor->sock, (struct sockaddr *)&snl, &addrlen);
if (err == 0)
udev_monitor->snl.nl_pid = snl.nl_pid;
}
} else {
return -EINVAL;
}
if (err < 0) {
err(udev_monitor->udev, "bind failed: %m\n");
return err;
}
/* enable receiving of sender credentials */
setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
return 0;
}
/**
* udev_monitor_set_receive_buffer_size:
* @udev_monitor: the monitor which should receive events
* @size: the size in bytes
*
* Set the size of the kernel socket buffer. This call needs the
* appropriate privileges to succeed.
*
* Returns: 0 on success, otherwise -1 on error.
*/
int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size)
{
if (udev_monitor == NULL)
return -1;
return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size));
}
int udev_monitor_disconnect(struct udev_monitor *udev_monitor)
{
int err;
err = close(udev_monitor->sock);
udev_monitor->sock = -1;
return err;
}
/**
* udev_monitor_ref:
* @udev_monitor: udev monitor
*
* Take a reference of a udev monitor.
*
* Returns: the passed udev monitor
**/
struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return NULL;
udev_monitor->refcount++;
return udev_monitor;
}
/**
* udev_monitor_unref:
* @udev_monitor: udev monitor
*
* Drop a reference of a udev monitor. If the refcount reaches zero,
* the bound socket will be closed, and the resources of the monitor
* will be released.
*
**/
void udev_monitor_unref(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return;
udev_monitor->refcount--;
if (udev_monitor->refcount > 0)
return;
if (udev_monitor->sock >= 0)
close(udev_monitor->sock);
udev_list_cleanup_entries(udev_monitor->udev, &udev_monitor->filter_subsystem_list);
udev_list_cleanup_entries(udev_monitor->udev, &udev_monitor->filter_tag_list);
dbg(udev_monitor->udev, "monitor %p released\n", udev_monitor);
free(udev_monitor);
}
/**
* udev_monitor_get_udev:
* @udev_monitor: udev monitor
*
* Retrieve the udev library context the monitor was created with.
*
* Returns: the udev library context
**/
struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return NULL;
return udev_monitor->udev;
}
/**
* udev_monitor_get_fd:
* @udev_monitor: udev monitor
*
* Retrieve the socket file descriptor associated with the monitor.
*
* Returns: the socket file descriptor
**/
int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return -1;
return udev_monitor->sock;
}
static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *udev_device)
{
struct udev_list_entry *list_entry;
if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL)
goto tag;
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) {
const char *subsys = udev_list_entry_get_name(list_entry);
const char *dsubsys = udev_device_get_subsystem(udev_device);
const char *devtype;
const char *ddevtype;
if (strcmp(dsubsys, subsys) != 0)
continue;
devtype = udev_list_entry_get_value(list_entry);
if (devtype == NULL)
goto tag;
ddevtype = udev_device_get_devtype(udev_device);
if (ddevtype == NULL)
continue;
if (strcmp(ddevtype, devtype) == 0)
goto tag;
}
return 0;
tag:
if (udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL)
return 1;
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) {
const char *tag = udev_list_entry_get_name(list_entry);
if (udev_device_has_tag(udev_device, tag))
return 1;
}
return 0;
}
/**
* udev_monitor_receive_device:
* @udev_monitor: udev monitor
*
* Receive data from the udev monitor socket, allocate a new udev
* device, fill in the received data, and return the device.
*
* Only socket connections with uid=0 are accepted. The caller
* needs to make sure that there is data to read from the socket.
* The call will block until the socket becomes readable.
*
* The initial refcount is 1, and needs to be decremented to
* release the resources of the udev device.
*
* Returns: a new udev device, or #NULL, in case of an error
**/
struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
{
struct udev_device *udev_device;
struct msghdr smsg;
struct iovec iov;
char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
struct cmsghdr *cmsg;
struct sockaddr_nl snl;
struct ucred *cred;
char buf[8192];
ssize_t buflen;
ssize_t bufpos;
struct udev_monitor_netlink_header *nlh;
retry:
if (udev_monitor == NULL)
return NULL;
memset(buf, 0x00, sizeof(buf));
iov.iov_base = &buf;
iov.iov_len = sizeof(buf);
memset (&smsg, 0x00, sizeof(struct msghdr));
smsg.msg_iov = &iov;
smsg.msg_iovlen = 1;
smsg.msg_control = cred_msg;
smsg.msg_controllen = sizeof(cred_msg);
if (udev_monitor->snl.nl_family != 0) {
smsg.msg_name = &snl;
smsg.msg_namelen = sizeof(snl);
}
buflen = recvmsg(udev_monitor->sock, &smsg, 0);
if (buflen < 0) {
if (errno != EINTR)
info(udev_monitor->udev, "unable to receive message\n");
return NULL;
}
if (buflen < 32 || (size_t)buflen >= sizeof(buf)) {
info(udev_monitor->udev, "invalid message length\n");
return NULL;
}
if (udev_monitor->snl.nl_family != 0) {
if (snl.nl_groups == 0) {
/* unicast message, check if we trust the sender */
if (udev_monitor->snl_trusted_sender.nl_pid == 0 ||
snl.nl_pid != udev_monitor->snl_trusted_sender.nl_pid) {
info(udev_monitor->udev, "unicast netlink message ignored\n");
return NULL;
}
} else if (snl.nl_groups == UDEV_MONITOR_KERNEL) {
if (snl.nl_pid > 0) {
info(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n",
snl.nl_pid);
return NULL;
}
}
}
cmsg = CMSG_FIRSTHDR(&smsg);
if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
info(udev_monitor->udev, "no sender credentials received, message ignored\n");
return NULL;
}
cred = (struct ucred *)CMSG_DATA(cmsg);
if (cred->uid != 0) {
info(udev_monitor->udev, "sender uid=%d, message ignored\n", cred->uid);
return NULL;
}
if (memcmp(buf, "libudev", 8) == 0) {
/* udev message needs proper version magic */
nlh = (struct udev_monitor_netlink_header *) buf;
if (nlh->magic != htonl(UDEV_MONITOR_MAGIC)) {
err(udev_monitor->udev, "ignored a message from an invalid release of udevadm (%x != %x)\n",
nlh->magic, htonl(UDEV_MONITOR_MAGIC));
return NULL;
}
if (nlh->properties_off+32 > buflen)
return NULL;
bufpos = nlh->properties_off;
} else {
/* kernel message with header */
bufpos = strlen(buf) + 1;
if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) {
info(udev_monitor->udev, "invalid message length\n");
return NULL;
}
/* check message header */
if (strstr(buf, "@/") == NULL) {
info(udev_monitor->udev, "unrecognized message header\n");
return NULL;
}
}
udev_device = udev_device_new(udev_monitor->udev);
if (udev_device == NULL)
return NULL;
udev_device_set_info_loaded(udev_device);
while (bufpos < buflen) {
char *key;
size_t keylen;
key = &buf[bufpos];
keylen = strlen(key);
if (keylen == 0)
break;
bufpos += keylen + 1;
udev_device_add_property_from_string_parse(udev_device, key);
}
if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) {
info(udev_monitor->udev, "missing values, invalid device\n");
udev_device_unref(udev_device);
return NULL;
}
/* skip device, if it does not pass the current filter */
if (!passes_filter(udev_monitor, udev_device)) {
struct pollfd pfd[1];
int rc;
udev_device_unref(udev_device);
/* if something is queued, get next device */
pfd[0].fd = udev_monitor->sock;
pfd[0].events = POLLIN;
rc = poll(pfd, 1, 0);
if (rc > 0)
goto retry;
return NULL;
}
return udev_device;
}
int udev_monitor_send_device(struct udev_monitor *udev_monitor,
struct udev_monitor *destination, struct udev_device *udev_device)
{
const char *buf;
ssize_t blen;
ssize_t count;
blen = udev_device_get_properties_monitor_buf(udev_device, &buf);
if (blen < 32)
return -EINVAL;
if (udev_monitor->sun.sun_family != 0) {
struct msghdr smsg;
struct iovec iov[2];
const char *action;
char header[2048];
char *s;
/* header <action>@<devpath> */
action = udev_device_get_action(udev_device);
if (action == NULL)
return -EINVAL;
s = header;
if (util_strpcpyl(&s, sizeof(header), action, "@", udev_device_get_devpath(udev_device), NULL) == 0)
return -EINVAL;
iov[0].iov_base = header;
iov[0].iov_len = (s - header)+1;
/* add properties list */
iov[1].iov_base = (char *)buf;
iov[1].iov_len = blen;
memset(&smsg, 0x00, sizeof(struct msghdr));
smsg.msg_iov = iov;
smsg.msg_iovlen = 2;
smsg.msg_name = &udev_monitor->sun;
smsg.msg_namelen = udev_monitor->addrlen;
count = sendmsg(udev_monitor->sock, &smsg, 0);
info(udev_monitor->udev, "passed %zi bytes to socket monitor %p\n", count, udev_monitor);
return count;
}
if (udev_monitor->snl.nl_family != 0) {
struct msghdr smsg;
struct iovec iov[2];
const char *val;
struct udev_monitor_netlink_header nlh;
struct udev_list_entry *list_entry;
uint64_t tag_bloom_bits;
/* add versioned header */
memset(&nlh, 0x00, sizeof(struct udev_monitor_netlink_header));
memcpy(nlh.prefix, "libudev", 8);
nlh.magic = htonl(UDEV_MONITOR_MAGIC);
nlh.header_size = sizeof(struct udev_monitor_netlink_header);
val = udev_device_get_subsystem(udev_device);
nlh.filter_subsystem_hash = htonl(util_string_hash32(val));
val = udev_device_get_devtype(udev_device);
if (val != NULL)
nlh.filter_devtype_hash = htonl(util_string_hash32(val));
iov[0].iov_base = &nlh;
iov[0].iov_len = sizeof(struct udev_monitor_netlink_header);
/* add tag bloom filter */
tag_bloom_bits = 0;
udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
tag_bloom_bits |= util_string_bloom64(udev_list_entry_get_name(list_entry));
if (tag_bloom_bits > 0) {
nlh.filter_tag_bloom_hi = htonl(tag_bloom_bits >> 32);
nlh.filter_tag_bloom_lo = htonl(tag_bloom_bits & 0xffffffff);
}
/* add properties list */
nlh.properties_off = iov[0].iov_len;
nlh.properties_len = blen;
iov[1].iov_base = (char *)buf;
iov[1].iov_len = blen;
memset(&smsg, 0x00, sizeof(struct msghdr));
smsg.msg_iov = iov;
smsg.msg_iovlen = 2;
/*
* Use custom address for target, or the default one.
*
* If we send to a multicast group, we will get
* ECONNREFUSED, which is expected.
*/
if (destination != NULL)
smsg.msg_name = &destination->snl;
else
smsg.msg_name = &udev_monitor->snl_destination;
smsg.msg_namelen = sizeof(struct sockaddr_nl);
count = sendmsg(udev_monitor->sock, &smsg, 0);
info(udev_monitor->udev, "passed %zi bytes to netlink monitor %p\n", count, udev_monitor);
return count;
}
return -EINVAL;
}
/**
* udev_monitor_filter_add_match_subsystem_devtype:
* @udev_monitor: the monitor
* @subsystem: the subsystem value to match the incoming devices against
* @devtype: the devtype value to match the incoming devices against
*
* This filer is efficiently executed inside the kernel, and libudev subscribers
* will usually not be woken up for devices which do not match.
*
* The filter must be installed before the monitor is switched to listening mode.
*
* Returns: 0 on success, otherwise a negative error value.
*/
int udev_monitor_filter_add_match_subsystem_devtype(struct udev_monitor *udev_monitor, const char *subsystem, const char *devtype)
{
if (udev_monitor == NULL)
return -EINVAL;
if (subsystem == NULL)
return -EINVAL;
if (udev_list_entry_add(udev_monitor->udev,
&udev_monitor->filter_subsystem_list, subsystem, devtype, 0, 0) == NULL)
return -ENOMEM;
return 0;
}
/**
* udev_monitor_filter_add_match_tag:
* @udev_monitor: the monitor
* @tag: the name of a tag
*
* This filer is efficiently executed inside the kernel, and libudev subscribers
* will usually not be woken up for devices which do not match.
*
* The filter must be installed before the monitor is switched to listening mode.
*
* Returns: 0 on success, otherwise a negative error value.
*/
int udev_monitor_filter_add_match_tag(struct udev_monitor *udev_monitor, const char *tag)
{
if (udev_monitor == NULL)
return -EINVAL;
if (tag == NULL)
return -EINVAL;
if (udev_list_entry_add(udev_monitor->udev,
&udev_monitor->filter_tag_list, tag, NULL, 0, 0) == NULL)
return -ENOMEM;
return 0;
}
/**
* udev_monitor_filter_remove:
* @udev_monitor: monitor
*
* Remove all filters from monitor.
*
* Returns: 0 on success, otherwise a negative error value.
*/
int udev_monitor_filter_remove(struct udev_monitor *udev_monitor)
{
static struct sock_fprog filter = { 0, NULL };
udev_list_cleanup_entries(udev_monitor->udev, &udev_monitor->filter_subsystem_list);
return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter));
}
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