| /*** |
| This file is part of systemd. |
| |
| Copyright 2008-2012 Kay Sievers <kay@vrfy.org> |
| |
| systemd 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. |
| |
| systemd is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <stddef.h> |
| #include <unistd.h> |
| #include <errno.h> |
| #include <string.h> |
| #include <poll.h> |
| #include <sys/socket.h> |
| #include <linux/netlink.h> |
| #include <linux/filter.h> |
| |
| #include "libudev.h" |
| #include "libudev-private.h" |
| #include "socket-util.h" |
| #include "missing.h" |
| #include "formats-util.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; |
| union sockaddr_union snl; |
| union sockaddr_union snl_trusted_sender; |
| union sockaddr_union snl_destination; |
| 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 = new0(struct udev_monitor, 1); |
| 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; |
| } |
| |
| /* we consider udev running when /dev is on devtmpfs */ |
| static bool udev_has_devtmpfs(struct udev *udev) { |
| |
| union file_handle_union h = FILE_HANDLE_INIT; |
| _cleanup_fclose_ FILE *f = NULL; |
| char line[LINE_MAX], *e; |
| int mount_id; |
| int r; |
| |
| r = name_to_handle_at(AT_FDCWD, "/dev", &h.handle, &mount_id, 0); |
| if (r < 0) { |
| if (errno != EOPNOTSUPP) |
| log_debug_errno(errno, "name_to_handle_at on /dev: %m"); |
| return false; |
| } |
| |
| f = fopen("/proc/self/mountinfo", "re"); |
| if (!f) |
| return false; |
| |
| FOREACH_LINE(line, f, return false) { |
| int mid; |
| |
| if (sscanf(line, "%i", &mid) != 1) |
| continue; |
| |
| if (mid != mount_id) |
| continue; |
| |
| e = strstr(line, " - "); |
| if (!e) |
| continue; |
| |
| /* accept any name that starts with the currently expected type */ |
| if (startswith(e + 3, "devtmpfs")) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static void monitor_set_nl_address(struct udev_monitor *udev_monitor) { |
| union sockaddr_union snl; |
| socklen_t addrlen; |
| int r; |
| |
| assert(udev_monitor); |
| |
| /* get the address the kernel has assigned us |
| * it is usually, but not necessarily the pid |
| */ |
| addrlen = sizeof(struct sockaddr_nl); |
| r = getsockname(udev_monitor->sock, &snl.sa, &addrlen); |
| if (r >= 0) |
| udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid; |
| } |
| |
| 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 (streq(name, "udev")) { |
| /* |
| * We do not support subscribing to uevents if no instance of |
| * udev is running. Uevents would otherwise broadcast the |
| * processing data of the host into containers, which is not |
| * desired. |
| * |
| * Containers will currently not get any udev uevents, until |
| * a supporting infrastructure is available. |
| * |
| * We do not set a netlink multicast group here, so the socket |
| * will not receive any messages. |
| */ |
| if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) { |
| log_debug("the udev service seems not to be active, disable the monitor"); |
| group = UDEV_MONITOR_NONE; |
| } else |
| group = UDEV_MONITOR_UDEV; |
| } else if (streq(name, "kernel")) |
| 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 < 0) { |
| log_debug_errno(errno, "error getting socket: %m"); |
| free(udev_monitor); |
| return NULL; |
| } |
| } else { |
| udev_monitor->bound = true; |
| udev_monitor->sock = fd; |
| monitor_set_nl_address(udev_monitor); |
| } |
| |
| udev_monitor->snl.nl.nl_family = AF_NETLINK; |
| udev_monitor->snl.nl.nl_groups = group; |
| |
| /* default destination for sending */ |
| udev_monitor->snl_destination.nl.nl_family = AF_NETLINK; |
| udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV; |
| |
| 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 |
| **/ |
| _public_ 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. |
| */ |
| _public_ 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; |
| |
| memzero(ins, 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 >= ELEMENTSOF(ins)) |
| return -E2BIG; |
| } |
| |
| /* 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 */ |
| memzero(&filter, sizeof(filter)); |
| filter.len = i; |
| filter.filter = ins; |
| err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)); |
| return err < 0 ? -errno : 0; |
| } |
| |
| int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender) |
| { |
| udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.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. |
| */ |
| _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor) |
| { |
| int err = 0; |
| const int on = 1; |
| |
| udev_monitor_filter_update(udev_monitor); |
| |
| if (!udev_monitor->bound) { |
| err = bind(udev_monitor->sock, |
| &udev_monitor->snl.sa, sizeof(struct sockaddr_nl)); |
| if (err == 0) |
| udev_monitor->bound = true; |
| } |
| |
| if (err >= 0) |
| monitor_set_nl_address(udev_monitor); |
| else { |
| log_debug_errno(errno, "bind failed: %m"); |
| return -errno; |
| } |
| |
| /* enable receiving of sender credentials */ |
| err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); |
| if (err < 0) |
| log_debug_errno(errno, "setting SO_PASSCRED failed: %m"); |
| |
| 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. |
| */ |
| _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size) |
| { |
| if (udev_monitor == NULL) |
| return -EINVAL; |
| 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 < 0 ? -errno : 0; |
| } |
| |
| /** |
| * udev_monitor_ref: |
| * @udev_monitor: udev monitor |
| * |
| * Take a reference of a udev monitor. |
| * |
| * Returns: the passed udev monitor |
| **/ |
| _public_ 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. |
| * |
| * Returns: #NULL |
| **/ |
| _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor) |
| { |
| if (udev_monitor == NULL) |
| return NULL; |
| udev_monitor->refcount--; |
| if (udev_monitor->refcount > 0) |
| return NULL; |
| 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); |
| free(udev_monitor); |
| return NULL; |
| } |
| |
| /** |
| * udev_monitor_get_udev: |
| * @udev_monitor: udev monitor |
| * |
| * Retrieve the udev library context the monitor was created with. |
| * |
| * Returns: the udev library context |
| **/ |
| _public_ 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 |
| **/ |
| _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) |
| { |
| if (udev_monitor == NULL) |
| return -EINVAL; |
| 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 (!streq(dsubsys, subsys)) |
| 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 (streq(ddevtype, devtype)) |
| 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 monitor socket is by default set to NONBLOCK. A variant of poll() on |
| * the file descriptor returned by udev_monitor_get_fd() should to be used to |
| * wake up when new devices arrive, or alternatively the file descriptor |
| * switched into blocking mode. |
| * |
| * 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 |
| **/ |
| _public_ 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; |
| union sockaddr_union snl; |
| struct ucred *cred; |
| union { |
| struct udev_monitor_netlink_header nlh; |
| char raw[8192]; |
| } buf; |
| ssize_t buflen; |
| ssize_t bufpos; |
| bool is_initialized = false; |
| |
| retry: |
| if (udev_monitor == NULL) |
| return NULL; |
| iov.iov_base = &buf; |
| iov.iov_len = sizeof(buf); |
| memzero(&smsg, sizeof(struct msghdr)); |
| smsg.msg_iov = &iov; |
| smsg.msg_iovlen = 1; |
| smsg.msg_control = cred_msg; |
| smsg.msg_controllen = sizeof(cred_msg); |
| smsg.msg_name = &snl; |
| smsg.msg_namelen = sizeof(snl); |
| |
| buflen = recvmsg(udev_monitor->sock, &smsg, 0); |
| if (buflen < 0) { |
| if (errno != EINTR) |
| log_debug("unable to receive message"); |
| return NULL; |
| } |
| |
| if (buflen < 32 || (smsg.msg_flags & MSG_TRUNC)) { |
| log_debug("invalid message length"); |
| return NULL; |
| } |
| |
| if (snl.nl.nl_groups == 0) { |
| /* unicast message, check if we trust the sender */ |
| if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 || |
| snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) { |
| log_debug("unicast netlink message ignored"); |
| return NULL; |
| } |
| } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) { |
| if (snl.nl.nl_pid > 0) { |
| log_debug("multicast kernel netlink message from PID %"PRIu32" ignored", |
| snl.nl.nl_pid); |
| return NULL; |
| } |
| } |
| |
| cmsg = CMSG_FIRSTHDR(&smsg); |
| if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { |
| log_debug("no sender credentials received, message ignored"); |
| return NULL; |
| } |
| |
| cred = (struct ucred *)CMSG_DATA(cmsg); |
| if (cred->uid != 0) { |
| log_debug("sender uid="UID_FMT", message ignored", cred->uid); |
| return NULL; |
| } |
| |
| if (memcmp(buf.raw, "libudev", 8) == 0) { |
| /* udev message needs proper version magic */ |
| if (buf.nlh.magic != htonl(UDEV_MONITOR_MAGIC)) { |
| log_debug("unrecognized message signature (%x != %x)", |
| buf.nlh.magic, htonl(UDEV_MONITOR_MAGIC)); |
| return NULL; |
| } |
| if (buf.nlh.properties_off+32 > (size_t)buflen) { |
| log_debug("message smaller than expected (%u > %zd)", |
| buf.nlh.properties_off+32, buflen); |
| return NULL; |
| } |
| |
| bufpos = buf.nlh.properties_off; |
| |
| /* devices received from udev are always initialized */ |
| is_initialized = true; |
| } else { |
| /* kernel message with header */ |
| bufpos = strlen(buf.raw) + 1; |
| if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) { |
| log_debug("invalid message length"); |
| return NULL; |
| } |
| |
| /* check message header */ |
| if (strstr(buf.raw, "@/") == NULL) { |
| log_debug("unrecognized message header"); |
| return NULL; |
| } |
| } |
| |
| udev_device = udev_device_new_from_nulstr(udev_monitor->udev, &buf.raw[bufpos], buflen - bufpos); |
| if (!udev_device) { |
| log_debug("could not create device: %m"); |
| return NULL; |
| } |
| |
| if (is_initialized) |
| udev_device_set_is_initialized(udev_device); |
| |
| /* 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, *val; |
| ssize_t blen, count; |
| struct udev_monitor_netlink_header nlh = { |
| .prefix = "libudev", |
| .magic = htonl(UDEV_MONITOR_MAGIC), |
| .header_size = sizeof nlh, |
| }; |
| struct iovec iov[2] = { |
| { .iov_base = &nlh, .iov_len = sizeof nlh }, |
| }; |
| struct msghdr smsg = { |
| .msg_iov = iov, |
| .msg_iovlen = 2, |
| }; |
| struct udev_list_entry *list_entry; |
| uint64_t tag_bloom_bits; |
| |
| blen = udev_device_get_properties_monitor_buf(udev_device, &buf); |
| if (blen < 32) { |
| log_debug("device buffer is too small to contain a valid device"); |
| return -EINVAL; |
| } |
| |
| /* fill in versioned 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)); |
| |
| /* 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; |
| |
| /* |
| * 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) |
| 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); |
| if (count < 0) { |
| if (!destination && errno == ECONNREFUSED) { |
| log_debug("passed device to netlink monitor %p", udev_monitor); |
| return 0; |
| } else |
| return -errno; |
| } |
| |
| log_debug("passed %zi byte device to netlink monitor %p", count, udev_monitor); |
| return count; |
| } |
| |
| /** |
| * 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. |
| */ |
| _public_ 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. |
| */ |
| _public_ 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. |
| */ |
| _public_ 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)); |
| } |