| /* |
| * 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 an 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 filter_subsystem_list; |
| struct udev_list filter_tag_list; |
| bool bound; |
| }; |
| |
| 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, &udev_monitor->filter_subsystem_list, false); |
| udev_list_init(udev, &udev_monitor->filter_tag_list, true); |
| return udev_monitor; |
| } |
| |
| /** |
| * udev_monitor_new_from_socket: |
| * @udev: udev library context |
| * @socket_path: unix socket path |
| * |
| * This function should not be used in any new application. The |
| * kernel's netlink socket multiplexes messages to all interested |
| * clients. Creating custom sockets from udev to applications |
| * should be avoided. |
| * |
| * Create a 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 |
| **/ |
| UDEV_EXPORT 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_NONBLOCK|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; |
| } |
| |
| 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 == 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; |
| |
| if (fd < 0) { |
| udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, 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; |
| } |
| |
| 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; |
| } |
| |
| /** |
| * 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 |
| **/ |
| UDEV_EXPORT 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) |
| { |
| 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 socket filter. This is only needed, |
| * if the filter was removed or changed. |
| * |
| * Returns: 0 on success, otherwise a negative error value. |
| */ |
| UDEV_EXPORT 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. |
| */ |
| UDEV_EXPORT int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
| { |
| int err = 0; |
| const int on = 1; |
| |
| if (udev_monitor->sun.sun_family != 0) { |
| 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); |
| 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 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. |
| */ |
| UDEV_EXPORT 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 |
| **/ |
| UDEV_EXPORT 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. |
| * |
| **/ |
| UDEV_EXPORT 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(&udev_monitor->filter_subsystem_list); |
| udev_list_cleanup(&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 |
| **/ |
| UDEV_EXPORT 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 |
| **/ |
| UDEV_EXPORT 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 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 |
| **/ |
| UDEV_EXPORT 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, "unrecognized message signature (%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 filter 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. |
| */ |
| UDEV_EXPORT 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->filter_subsystem_list, subsystem, devtype) == NULL) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| /** |
| * udev_monitor_filter_add_match_tag: |
| * @udev_monitor: the monitor |
| * @tag: the name of a tag |
| * |
| * This filter 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. |
| */ |
| UDEV_EXPORT 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->filter_tag_list, tag, NULL) == 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. |
| */ |
| UDEV_EXPORT int udev_monitor_filter_remove(struct udev_monitor *udev_monitor) |
| { |
| static struct sock_fprog filter = { 0, NULL }; |
| |
| udev_list_cleanup(&udev_monitor->filter_subsystem_list); |
| return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); |
| } |
