diff options
Diffstat (limited to 'libudev/libudev-monitor.c')
| -rw-r--r-- | libudev/libudev-monitor.c | 760 |
1 files changed, 760 insertions, 0 deletions
diff --git a/libudev/libudev-monitor.c b/libudev/libudev-monitor.c new file mode 100644 index 0000000000..7a0cb47852 --- /dev/null +++ b/libudev/libudev-monitor.c @@ -0,0 +1,760 @@ +/* + * libudev - interface to udev device information + * + * Copyright (C) 2008-2009 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" + +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; +}; + +enum udev_monitor_netlink_group { + UDEV_MONITOR_NONE, + UDEV_MONITOR_KERNEL, + UDEV_MONITOR_UDEV, +}; + +#define UDEV_MONITOR_MAGIC 0xcafe1dea +struct udev_monitor_netlink_header { + /* udev version text */ + char version[16]; + /* + * 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; + /* + * 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 + */ + unsigned int filter_subsystem; + unsigned int filter_devtype; +}; + +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); + 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, 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; + 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, NETLINK_KOBJECT_UEVENT); + if (udev_monitor->sock == -1) { + err(udev, "error getting socket: %m\n"); + free(udev_monitor); + return NULL; + } + util_set_fd_cloexec(udev_monitor->sock); + + 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)++; +} + +int udev_monitor_filter_update(struct udev_monitor *udev_monitor) +{ + static struct sock_filter ins[256]; + static 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) + 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); + + /* 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); + } + + /* 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); + + /* install 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; +} + +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 neccessarily 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; +} + +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); + 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) + return 1; + + 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) + return 1; + ddevtype = udev_device_get_devtype(udev_device); + if (ddevtype == NULL) + continue; + if (strcmp(ddevtype, devtype) == 0) + 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; + 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) + 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; + } + is_kernel = 1; + } + } + + 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 (strncmp(buf, "udev-", 5) == 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)) + 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 = device_new(udev_monitor->udev); + if (udev_device == NULL) { + return NULL; + } + + while (bufpos < buflen) { + char *key; + size_t keylen; + + key = &buf[bufpos]; + keylen = strlen(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); + } + } + if (!devpath_set || !subsystem_set || !action_set) { + info(udev_monitor->udev, "missing values, skip\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; + } + + 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; + + if (udev_monitor->sun.sun_family != 0) { + 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; + } else if (udev_monitor->snl.nl_family != 0) { + const char *val; + struct udev_monitor_netlink_header nlh; + + + /* add versioned header */ + memset(&nlh, 0x00, sizeof(struct udev_monitor_netlink_header)); + util_strscpy(nlh.version, sizeof(nlh.version), "udev-" VERSION); + nlh.magic = htonl(UDEV_MONITOR_MAGIC); + val = udev_device_get_subsystem(udev_device); + nlh.filter_subsystem = htonl(util_string_hash32(val)); + val = udev_device_get_devtype(udev_device); + if (val != NULL) + nlh.filter_devtype = htonl(util_string_hash32(val)); + iov[0].iov_base = &nlh; + iov[0].iov_len = sizeof(struct udev_monitor_netlink_header); + + /* 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 muticast 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); + } else { + return -1; + } + + count = sendmsg(udev_monitor->sock, &smsg, 0); + info(udev_monitor->udev, "passed %zi bytes to monitor %p\n", count, udev_monitor); + return count; +} + +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 0; + if (udev_list_entry_add(udev_monitor->udev, + &udev_monitor->filter_subsystem_list, subsystem, devtype, 0, 0) == NULL) + return -ENOMEM; + return 0; +} + +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)); +} |