/*
* libudev - interface to udev device information
*
- * Copyright (C) 2008-2009 Kay Sievers <kay.sievers@vrfy.org>
+ * 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
* Connects to a device event source.
*/
-/**
/**
* udev_monitor:
*
struct sockaddr_un sun;
socklen_t addrlen;
struct udev_list_node filter_subsystem_list;
+ struct udev_list_node filter_tag_list;
+ bool bound;
};
enum udev_monitor_netlink_group {
UDEV_MONITOR_UDEV,
};
-#define UDEV_MONITOR_MAGIC 0xcafe1dea
+#define UDEV_MONITOR_MAGIC 0xfeedcafe
struct udev_monitor_netlink_header {
- /* udev version text */
- char version[16];
+ /* "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;
- /* properties buffer */
- unsigned short properties_off;
- unsigned short properties_len;
+ /* 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 some common device properties strings to filter with socket filters in
- * the client used in the kernel from socket filter rules; needs to be stored in
- * network order
+ * 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;
- unsigned int filter_devtype;
+ 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)
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;
}
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, 0);
+ udev_monitor->sock = socket(AF_LOCAL, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
if (udev_monitor->sock == -1) {
err(udev, "error getting socket: %m\n");
free(udev_monitor);
return NULL;
}
- util_set_fd_cloexec(udev_monitor->sock);
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_new_from_netlink_fd(struct udev *udev, const char *name, int fd)
{
struct udev_monitor *udev_monitor;
unsigned int group;
if (udev_monitor == NULL)
return NULL;
- udev_monitor->sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
- if (udev_monitor->sock == -1) {
- err(udev, "error getting socket: %m\n");
- free(udev_monitor);
- return NULL;
+ if (fd < 0) {
+ udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT);
+ if (udev_monitor->sock == -1) {
+ err(udev, "error getting socket: %m\n");
+ free(udev_monitor);
+ return NULL;
+ }
+ } else {
+ udev_monitor->bound = true;
+ udev_monitor->sock = fd;
}
- util_set_fd_cloexec(udev_monitor->sock);
udev_monitor->snl.nl_family = AF_NETLINK;
udev_monitor->snl.nl_groups = group;
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)
+{
+ return udev_monitor_new_from_netlink_fd(udev, name, -1);
+}
+
static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i,
unsigned short code, unsigned int data)
{
*/
int udev_monitor_filter_update(struct udev_monitor *udev_monitor)
{
- static struct sock_filter ins[256];
- static struct sock_fprog filter;
+ 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)
+ 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));
/* wrong magic, pass packet */
bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
- /* add all subsystem match values */
- udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) {
- unsigned int hash;
-
- /* load filter_subsystem value in A */
- bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem));
- hash = util_string_hash32(udev_list_entry_get_name(list_entry));
- 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 filter_devtype value in A */
- bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype));
- /* 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);
+ 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);
}
- /* matched, pass packet */
- bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
+ /* 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;
+ }
- if (i+1 >= ARRAY_SIZE(ins))
- return -1;
+ /* nothing matched, drop packet */
+ bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
}
- /* 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));
*/
int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
{
- int err;
+ int err = 0;
const int on = 1;
if (udev_monitor->sun.sun_family != 0) {
- err = bind(udev_monitor->sock,
- (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
+ if (!udev_monitor->bound) {
+ err = bind(udev_monitor->sock,
+ (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
+ if (err == 0)
+ udev_monitor->bound = true;
+ }
} 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 (!udev_monitor->bound) {
+ err = bind(udev_monitor->sock,
+ (struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
+ if (err == 0)
+ udev_monitor->bound = true;
+ }
if (err == 0) {
struct sockaddr_nl snl;
socklen_t addrlen;
/*
* get the address the kernel has assigned us
- * it is usually, but not neccessarily the pid
+ * it is usually, but not necessarily the pid
*/
addrlen = sizeof(struct sockaddr_nl);
err = getsockname(udev_monitor->sock, (struct sockaddr *)&snl, &addrlen);
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)
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);
}
struct udev_list_entry *list_entry;
if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL)
- return 1;
-
+ 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);
devtype = udev_list_entry_get_value(list_entry);
if (devtype == NULL)
- return 1;
+ 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;
ssize_t buflen;
ssize_t bufpos;
struct udev_monitor_netlink_header *nlh;
- int devpath_set = 0;
- int subsystem_set = 0;
- int action_set = 0;
- int maj = 0;
- int min = 0;
- int is_kernel = 0;
retry:
if (udev_monitor == 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);
+ info(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n",
+ snl.nl_pid);
return NULL;
}
- is_kernel = 1;
}
}
return NULL;
}
- if (strncmp(buf, "udev-", 5) == 0) {
+ 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))
- return NULL;
- if (nlh->properties_off < sizeof(struct udev_monitor_netlink_header))
+ 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;
}
udev_device = udev_device_new(udev_monitor->udev);
- if (udev_device == NULL) {
+ if (udev_device == NULL)
return NULL;
- }
+ udev_device_set_info_loaded(udev_device);
while (bufpos < buflen) {
char *key;
if (keylen == 0)
break;
bufpos += keylen + 1;
-
- if (strncmp(key, "DEVPATH=", 8) == 0) {
- char path[UTIL_PATH_SIZE];
-
- util_strscpyl(path, sizeof(path), udev_get_sys_path(udev_monitor->udev), &key[8], NULL);
- udev_device_set_syspath(udev_device, path);
- devpath_set = 1;
- } else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
- udev_device_set_subsystem(udev_device, &key[10]);
- subsystem_set = 1;
- } else if (strncmp(key, "DEVTYPE=", 8) == 0) {
- udev_device_set_devtype(udev_device, &key[8]);
- } else if (strncmp(key, "DEVNAME=", 8) == 0) {
- if (is_kernel)
- udev_device_set_knodename(udev_device, &key[8]);
- else
- udev_device_set_devnode(udev_device, &key[8]);
- } else if (strncmp(key, "DEVLINKS=", 9) == 0) {
- char devlinks[UTIL_PATH_SIZE];
- char *slink;
- char *next;
-
- util_strscpy(devlinks, sizeof(devlinks), &key[9]);
- slink = devlinks;
- next = strchr(slink, ' ');
- while (next != NULL) {
- next[0] = '\0';
- udev_device_add_devlink(udev_device, slink);
- slink = &next[1];
- next = strchr(slink, ' ');
- }
- if (slink[0] != '\0')
- udev_device_add_devlink(udev_device, slink);
- } else if (strncmp(key, "DRIVER=", 7) == 0) {
- udev_device_set_driver(udev_device, &key[7]);
- } else if (strncmp(key, "ACTION=", 7) == 0) {
- udev_device_set_action(udev_device, &key[7]);
- action_set = 1;
- } else if (strncmp(key, "MAJOR=", 6) == 0) {
- maj = strtoull(&key[6], NULL, 10);
- } else if (strncmp(key, "MINOR=", 6) == 0) {
- min = strtoull(&key[6], NULL, 10);
- } else if (strncmp(key, "DEVPATH_OLD=", 12) == 0) {
- udev_device_set_devpath_old(udev_device, &key[12]);
- } else if (strncmp(key, "SEQNUM=", 7) == 0) {
- udev_device_set_seqnum(udev_device, strtoull(&key[7], NULL, 10));
- } else if (strncmp(key, "TIMEOUT=", 8) == 0) {
- udev_device_set_timeout(udev_device, strtoull(&key[8], NULL, 10));
- } else {
- udev_device_add_property_from_string(udev_device, key);
- }
+ udev_device_add_property_from_string_parse(udev_device, key);
}
- if (!devpath_set || !subsystem_set || !action_set) {
- info(udev_monitor->udev, "missing values, skip\n");
+
+ 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;
}
return NULL;
}
- if (maj > 0)
- udev_device_set_devnum(udev_device, makedev(maj, min));
- udev_device_set_info_loaded(udev_device);
return udev_device;
}
int udev_monitor_send_device(struct udev_monitor *udev_monitor,
struct udev_monitor *destination, struct udev_device *udev_device)
{
- struct msghdr smsg;
- struct iovec iov[2];
const char *buf;
ssize_t blen;
ssize_t count;
blen = udev_device_get_properties_monitor_buf(udev_device, &buf);
if (blen < 32)
- return -1;
+ return -EINVAL;
if (udev_monitor->sun.sun_family != 0) {
+ struct msghdr smsg;
+ struct iovec iov[2];
const char *action;
char header[2048];
char *s;
smsg.msg_iovlen = 2;
smsg.msg_name = &udev_monitor->sun;
smsg.msg_namelen = udev_monitor->addrlen;
- } else if (udev_monitor->snl.nl_family != 0) {
+ 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));
- util_strscpy(nlh.version, sizeof(nlh.version), "udev-" VERSION);
+ 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 = htonl(util_string_hash32(val));
+ nlh.filter_subsystem_hash = htonl(util_string_hash32(val));
val = udev_device_get_devtype(udev_device);
if (val != NULL)
- nlh.filter_devtype = htonl(util_string_hash32(val));
+ 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;
/*
* Use custom address for target, or the default one.
*
- * If we send to a muticast group, we will get
+ * If we send to a multicast group, we will get
* ECONNREFUSED, which is expected.
*/
if (destination != NULL)
else
smsg.msg_name = &udev_monitor->snl_destination;
smsg.msg_namelen = sizeof(struct sockaddr_nl);
- } else {
- return -1;
+ count = sendmsg(udev_monitor->sock, &smsg, 0);
+ info(udev_monitor->udev, "passed %zi bytes to netlink monitor %p\n", count, udev_monitor);
+ return count;
}
- count = sendmsg(udev_monitor->sock, &smsg, 0);
- info(udev_monitor->udev, "passed %zi bytes to 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 matvh 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.
*
if (udev_monitor == NULL)
return -EINVAL;
if (subsystem == NULL)
- return 0;
+ return -EINVAL;
+ if (udev_list_entry_add(udev_monitor->udev,
+ &udev_monitor->filter_subsystem_list, subsystem, devtype, 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_subsystem_list, subsystem, devtype, 0, 0) == NULL)
+ &udev_monitor->filter_tag_list, tag, NULL, 0) == NULL)
return -ENOMEM;
return 0;
}
~ianmdlvl / elogind.git / blobdiff