866 lines
30 KiB
C
866 lines
30 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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/***
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This file is part of systemd.
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Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <linux/filter.h>
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#include <linux/netlink.h>
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#include <poll.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include "libudev.h"
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#include "alloc-util.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "format-util.h"
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#include "libudev-private.h"
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#include "missing.h"
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#include "mount-util.h"
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#include "socket-util.h"
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#include "string-util.h"
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/**
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* SECTION:libudev-monitor
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* @short_description: device event source
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*
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* Connects to a device event source.
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*/
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/**
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* udev_monitor:
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*
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* Opaque object handling an event source.
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*/
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struct udev_monitor {
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struct udev *udev;
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int refcount;
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int sock;
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union sockaddr_union snl;
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union sockaddr_union snl_trusted_sender;
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union sockaddr_union snl_destination;
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socklen_t addrlen;
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struct udev_list filter_subsystem_list;
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struct udev_list filter_tag_list;
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bool bound;
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};
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enum udev_monitor_netlink_group {
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UDEV_MONITOR_NONE,
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UDEV_MONITOR_KERNEL,
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UDEV_MONITOR_UDEV,
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};
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#define UDEV_MONITOR_MAGIC 0xfeedcafe
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struct udev_monitor_netlink_header {
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/* "libudev" prefix to distinguish libudev and kernel messages */
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char prefix[8];
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/*
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* magic to protect against daemon <-> library message format mismatch
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* used in the kernel from socket filter rules; needs to be stored in network order
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*/
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unsigned int magic;
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/* total length of header structure known to the sender */
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unsigned int header_size;
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/* properties string buffer */
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unsigned int properties_off;
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unsigned int properties_len;
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/*
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* hashes of primary device properties strings, to let libudev subscribers
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* use in-kernel socket filters; values need to be stored in network order
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*/
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unsigned int filter_subsystem_hash;
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unsigned int filter_devtype_hash;
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unsigned int filter_tag_bloom_hi;
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unsigned int filter_tag_bloom_lo;
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};
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static struct udev_monitor *udev_monitor_new(struct udev *udev) {
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struct udev_monitor *udev_monitor;
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udev_monitor = new0(struct udev_monitor, 1);
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if (udev_monitor == NULL) {
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errno = ENOMEM;
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return NULL;
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}
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udev_monitor->refcount = 1;
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udev_monitor->udev = udev;
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udev_list_init(udev, &udev_monitor->filter_subsystem_list, false);
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udev_list_init(udev, &udev_monitor->filter_tag_list, true);
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return udev_monitor;
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}
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/* we consider udev running when /dev is on devtmpfs */
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static bool udev_has_devtmpfs(struct udev *udev) {
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_cleanup_fclose_ FILE *f = NULL;
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char line[LINE_MAX], *e;
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int mount_id, r;
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r = path_get_mnt_id("/dev", &mount_id);
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if (r < 0) {
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if (r != -EOPNOTSUPP)
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log_debug_errno(r, "name_to_handle_at on /dev: %m");
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return false;
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}
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f = fopen("/proc/self/mountinfo", "re");
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if (!f)
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return false;
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FOREACH_LINE(line, f, return false) {
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int mid;
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if (sscanf(line, "%i", &mid) != 1)
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continue;
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if (mid != mount_id)
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continue;
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e = strstr(line, " - ");
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if (!e)
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continue;
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/* accept any name that starts with the currently expected type */
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if (startswith(e + 3, "devtmpfs"))
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return true;
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}
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return false;
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}
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static void monitor_set_nl_address(struct udev_monitor *udev_monitor) {
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union sockaddr_union snl;
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socklen_t addrlen;
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int r;
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assert(udev_monitor);
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/* get the address the kernel has assigned us
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* it is usually, but not necessarily the pid
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*/
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addrlen = sizeof(struct sockaddr_nl);
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r = getsockname(udev_monitor->sock, &snl.sa, &addrlen);
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if (r >= 0)
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udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid;
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}
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struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd) {
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struct udev_monitor *udev_monitor;
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unsigned int group;
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if (udev == NULL) {
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errno = EINVAL;
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return NULL;
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}
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if (name == NULL)
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group = UDEV_MONITOR_NONE;
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else if (streq(name, "udev")) {
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/*
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* We do not support subscribing to uevents if no instance of
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* udev is running. Uevents would otherwise broadcast the
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* processing data of the host into containers, which is not
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* desired.
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*
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* Containers will currently not get any udev uevents, until
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* a supporting infrastructure is available.
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*
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* We do not set a netlink multicast group here, so the socket
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* will not receive any messages.
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*/
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if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) {
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log_debug("the udev service seems not to be active, disable the monitor");
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group = UDEV_MONITOR_NONE;
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} else
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group = UDEV_MONITOR_UDEV;
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} else if (streq(name, "kernel"))
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group = UDEV_MONITOR_KERNEL;
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else {
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errno = EINVAL;
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return NULL;
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}
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udev_monitor = udev_monitor_new(udev);
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if (udev_monitor == NULL)
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return NULL;
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if (fd < 0) {
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udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT);
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if (udev_monitor->sock < 0) {
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log_debug_errno(errno, "error getting socket: %m");
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return mfree(udev_monitor);
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}
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} else {
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udev_monitor->bound = true;
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udev_monitor->sock = fd;
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monitor_set_nl_address(udev_monitor);
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}
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udev_monitor->snl.nl.nl_family = AF_NETLINK;
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udev_monitor->snl.nl.nl_groups = group;
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/* default destination for sending */
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udev_monitor->snl_destination.nl.nl_family = AF_NETLINK;
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udev_monitor->snl_destination.nl.nl_groups = UDEV_MONITOR_UDEV;
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return udev_monitor;
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}
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/**
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* udev_monitor_new_from_netlink:
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* @udev: udev library context
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* @name: name of event source
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*
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* Create new udev monitor and connect to a specified event
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* source. Valid sources identifiers are "udev" and "kernel".
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*
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* Applications should usually not connect directly to the
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* "kernel" events, because the devices might not be useable
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* at that time, before udev has configured them, and created
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* device nodes. Accessing devices at the same time as udev,
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* might result in unpredictable behavior. The "udev" events
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* are sent out after udev has finished its event processing,
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* all rules have been processed, and needed device nodes are
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* created.
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*
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* The initial refcount is 1, and needs to be decremented to
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* release the resources of the udev monitor.
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*
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* Returns: a new udev monitor, or #NULL, in case of an error
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**/
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_public_ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name) {
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return udev_monitor_new_from_netlink_fd(udev, name, -1);
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}
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static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i,
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unsigned short code, unsigned int data)
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{
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struct sock_filter *ins = &inss[*i];
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ins->code = code;
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ins->k = data;
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(*i)++;
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}
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static inline void bpf_jmp(struct sock_filter *inss, unsigned int *i,
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unsigned short code, unsigned int data,
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unsigned short jt, unsigned short jf)
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{
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struct sock_filter *ins = &inss[*i];
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ins->code = code;
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ins->jt = jt;
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ins->jf = jf;
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ins->k = data;
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(*i)++;
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}
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/**
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* udev_monitor_filter_update:
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* @udev_monitor: monitor
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*
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* Update the installed socket filter. This is only needed,
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* if the filter was removed or changed.
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*
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* Returns: 0 on success, otherwise a negative error value.
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*/
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_public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor)
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{
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struct sock_filter ins[512];
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struct sock_fprog filter;
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unsigned int i;
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struct udev_list_entry *list_entry;
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int err;
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if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) == NULL &&
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udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL)
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return 0;
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memzero(ins, sizeof(ins));
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i = 0;
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/* load magic in A */
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bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, magic));
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/* jump if magic matches */
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bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0);
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/* wrong magic, pass packet */
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bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
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if (udev_list_get_entry(&udev_monitor->filter_tag_list) != NULL) {
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int tag_matches;
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/* count tag matches, to calculate end of tag match block */
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tag_matches = 0;
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udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list))
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tag_matches++;
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/* add all tags matches */
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udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_tag_list)) {
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uint64_t tag_bloom_bits = util_string_bloom64(udev_list_entry_get_name(list_entry));
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uint32_t tag_bloom_hi = tag_bloom_bits >> 32;
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uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff;
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/* load device bloom bits in A */
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bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_hi));
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/* clear bits (tag bits & bloom bits) */
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bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi);
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/* jump to next tag if it does not match */
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bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3);
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/* load device bloom bits in A */
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bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_tag_bloom_lo));
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/* clear bits (tag bits & bloom bits) */
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bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo);
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/* jump behind end of tag match block if tag matches */
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tag_matches--;
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bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0);
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}
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/* nothing matched, drop packet */
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bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
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}
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/* add all subsystem matches */
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if (udev_list_get_entry(&udev_monitor->filter_subsystem_list) != NULL) {
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udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_monitor->filter_subsystem_list)) {
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unsigned int hash = util_string_hash32(udev_list_entry_get_name(list_entry));
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/* load device subsystem value in A */
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bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_subsystem_hash));
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if (udev_list_entry_get_value(list_entry) == NULL) {
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/* jump if subsystem does not match */
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bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1);
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} else {
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/* jump if subsystem does not match */
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bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3);
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/* load device devtype value in A */
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bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(struct udev_monitor_netlink_header, filter_devtype_hash));
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/* jump if value does not match */
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hash = util_string_hash32(udev_list_entry_get_value(list_entry));
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bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1);
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}
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/* matched, pass packet */
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bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
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if (i+1 >= ELEMENTSOF(ins))
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return -E2BIG;
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}
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/* nothing matched, drop packet */
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bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
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}
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/* matched, pass packet */
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bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
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/* install filter */
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memzero(&filter, sizeof(filter));
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filter.len = i;
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filter.filter = ins;
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err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter));
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return err < 0 ? -errno : 0;
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}
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int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender)
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{
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udev_monitor->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid;
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return 0;
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}
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/**
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* udev_monitor_enable_receiving:
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* @udev_monitor: the monitor which should receive events
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*
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* Binds the @udev_monitor socket to the event source.
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*
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* Returns: 0 on success, otherwise a negative error value.
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*/
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_public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
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{
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int err = 0;
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const int on = 1;
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udev_monitor_filter_update(udev_monitor);
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if (!udev_monitor->bound) {
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err = bind(udev_monitor->sock,
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&udev_monitor->snl.sa, sizeof(struct sockaddr_nl));
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if (err == 0)
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udev_monitor->bound = true;
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}
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if (err >= 0)
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monitor_set_nl_address(udev_monitor);
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else
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return log_debug_errno(errno, "bind failed: %m");
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/* enable receiving of sender credentials */
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err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
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if (err < 0)
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log_debug_errno(errno, "setting SO_PASSCRED failed: %m");
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return 0;
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}
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/**
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* udev_monitor_set_receive_buffer_size:
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* @udev_monitor: the monitor which should receive events
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* @size: the size in bytes
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*
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* Set the size of the kernel socket buffer. This call needs the
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* appropriate privileges to succeed.
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*
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* Returns: 0 on success, otherwise -1 on error.
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*/
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_public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size)
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{
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if (udev_monitor == NULL)
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return -EINVAL;
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if (setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size)) < 0)
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return -errno;
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return 0;
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}
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int udev_monitor_disconnect(struct udev_monitor *udev_monitor)
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{
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int err;
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err = close(udev_monitor->sock);
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udev_monitor->sock = -1;
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return err < 0 ? -errno : 0;
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}
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/**
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* udev_monitor_ref:
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* @udev_monitor: udev monitor
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*
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* Take a reference of a udev monitor.
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*
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* Returns: the passed udev monitor
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**/
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_public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
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{
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if (udev_monitor == NULL)
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return NULL;
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udev_monitor->refcount++;
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return udev_monitor;
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}
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/**
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* udev_monitor_unref:
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* @udev_monitor: udev monitor
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*
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* Drop a reference of a udev monitor. If the refcount reaches zero,
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* the bound socket will be closed, and the resources of the monitor
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* will be released.
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*
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* Returns: #NULL
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**/
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_public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor)
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{
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if (udev_monitor == NULL)
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return NULL;
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udev_monitor->refcount--;
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if (udev_monitor->refcount > 0)
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return NULL;
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if (udev_monitor->sock >= 0)
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close(udev_monitor->sock);
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udev_list_cleanup(&udev_monitor->filter_subsystem_list);
|
|
udev_list_cleanup(&udev_monitor->filter_tag_list);
|
|
return mfree(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
|
|
**/
|
|
_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) {
|
|
errno = EINVAL;
|
|
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");
|
|
errno = EINVAL;
|
|
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");
|
|
errno = EAGAIN;
|
|
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);
|
|
errno = EAGAIN;
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
cmsg = CMSG_FIRSTHDR(&smsg);
|
|
if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
|
|
log_debug("no sender credentials received, message ignored");
|
|
errno = EAGAIN;
|
|
return NULL;
|
|
}
|
|
|
|
cred = (struct ucred *)CMSG_DATA(cmsg);
|
|
if (cred->uid != 0) {
|
|
log_debug("sender uid="UID_FMT", message ignored", cred->uid);
|
|
errno = EAGAIN;
|
|
return NULL;
|
|
}
|
|
|
|
if (memcmp(buf.raw, "libudev", 8) == 0) {
|
|
/* udev message needs proper version magic */
|
|
if (buf.nlh.magic != htobe32(UDEV_MONITOR_MAGIC)) {
|
|
log_debug("unrecognized message signature (%x != %x)",
|
|
buf.nlh.magic, htobe32(UDEV_MONITOR_MAGIC));
|
|
errno = EAGAIN;
|
|
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);
|
|
errno = EAGAIN;
|
|
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");
|
|
errno = EAGAIN;
|
|
return NULL;
|
|
}
|
|
|
|
/* check message header */
|
|
if (strstr(buf.raw, "@/") == NULL) {
|
|
log_debug("unrecognized message header");
|
|
errno = EAGAIN;
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
udev_device = udev_device_new_from_nulstr(udev_monitor->udev, &buf.raw[bufpos], buflen - bufpos);
|
|
if (!udev_device) {
|
|
log_debug_errno(errno, "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;
|
|
|
|
errno = EAGAIN;
|
|
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 = htobe32(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 = htobe32(util_string_hash32(val));
|
|
|
|
val = udev_device_get_devtype(udev_device);
|
|
if (val != NULL)
|
|
nlh.filter_devtype_hash = htobe32(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 = htobe32(tag_bloom_bits >> 32);
|
|
nlh.filter_tag_bloom_lo = htobe32(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 const struct sock_fprog filter = { 0, NULL };
|
|
|
|
udev_list_cleanup(&udev_monitor->filter_subsystem_list);
|
|
if (setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) < 0)
|
|
return -errno;
|
|
|
|
return 0;
|
|
}
|