+++ /dev/null
-/* -*- Mode: C; c-basic-offset:8 ; indent-tabs-mode:t -*- */
-/*
- * Linux usbfs backend for libusb
- * Copyright (C) 2007-2009 Daniel Drake <dsd@gentoo.org>
- * Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com>
- * Copyright (c) 2013 Nathan Hjelm <hjelmn@mac.com>
- * Copyright (c) 2016 Chris Dickens <christopher.a.dickens@gmail.com>
- *
- * 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.
- *
- * This library 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 this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <config.h>
-
-#include <assert.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <poll.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/types.h>
-
-#ifdef HAVE_ASM_TYPES_H
-#include <asm/types.h>
-#endif
-
-#include <sys/socket.h>
-#include <linux/netlink.h>
-
-#include "libusbi.h"
-#include "linux_usbfs.h"
-
-#define NL_GROUP_KERNEL 1
-
-#ifndef SOCK_CLOEXEC
-#define SOCK_CLOEXEC 0
-#endif
-
-#ifndef SOCK_NONBLOCK
-#define SOCK_NONBLOCK 0
-#endif
-
-static int linux_netlink_socket = -1;
-static int netlink_control_pipe[2] = { -1, -1 };
-static pthread_t libusb_linux_event_thread;
-
-static void *linux_netlink_event_thread_main(void *arg);
-
-static int set_fd_cloexec_nb(int fd, int socktype)
-{
- int flags;
-
-#if defined(FD_CLOEXEC)
- /* Make sure the netlink socket file descriptor is marked as CLOEXEC */
- if (!(socktype & SOCK_CLOEXEC)) {
- flags = fcntl(fd, F_GETFD);
- if (flags == -1) {
- usbi_err(NULL, "failed to get netlink fd flags (%d)", errno);
- return -1;
- }
-
- if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1) {
- usbi_err(NULL, "failed to set netlink fd flags (%d)", errno);
- return -1;
- }
- }
-#endif
-
- /* Make sure the netlink socket is non-blocking */
- if (!(socktype & SOCK_NONBLOCK)) {
- flags = fcntl(fd, F_GETFL);
- if (flags == -1) {
- usbi_err(NULL, "failed to get netlink fd status flags (%d)", errno);
- return -1;
- }
-
- if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
- usbi_err(NULL, "failed to set netlink fd status flags (%d)", errno);
- return -1;
- }
- }
-
- return 0;
-}
-
-int linux_netlink_start_event_monitor(void)
-{
- struct sockaddr_nl sa_nl = { .nl_family = AF_NETLINK, .nl_groups = NL_GROUP_KERNEL };
- int socktype = SOCK_RAW | SOCK_NONBLOCK | SOCK_CLOEXEC;
- int opt = 1;
- int ret;
-
- linux_netlink_socket = socket(PF_NETLINK, socktype, NETLINK_KOBJECT_UEVENT);
- if (linux_netlink_socket == -1 && errno == EINVAL) {
- usbi_dbg("failed to create netlink socket of type %d, attempting SOCK_RAW", socktype);
- socktype = SOCK_RAW;
- linux_netlink_socket = socket(PF_NETLINK, socktype, NETLINK_KOBJECT_UEVENT);
- }
-
- if (linux_netlink_socket == -1) {
- usbi_err(NULL, "failed to create netlink socket (%d)", errno);
- goto err;
- }
-
- ret = set_fd_cloexec_nb(linux_netlink_socket, socktype);
- if (ret == -1)
- goto err_close_socket;
-
- ret = bind(linux_netlink_socket, (struct sockaddr *)&sa_nl, sizeof(sa_nl));
- if (ret == -1) {
- usbi_err(NULL, "failed to bind netlink socket (%d)", errno);
- goto err_close_socket;
- }
-
- ret = setsockopt(linux_netlink_socket, SOL_SOCKET, SO_PASSCRED, &opt, sizeof(opt));
- if (ret == -1) {
- usbi_err(NULL, "failed to set netlink socket SO_PASSCRED option (%d)", errno);
- goto err_close_socket;
- }
-
- ret = usbi_pipe(netlink_control_pipe);
- if (ret) {
- usbi_err(NULL, "failed to create netlink control pipe");
- goto err_close_socket;
- }
-
- ret = pthread_create(&libusb_linux_event_thread, NULL, linux_netlink_event_thread_main, NULL);
- if (ret != 0) {
- usbi_err(NULL, "failed to create netlink event thread (%d)", ret);
- goto err_close_pipe;
- }
-
- return LIBUSB_SUCCESS;
-
-err_close_pipe:
- close(netlink_control_pipe[0]);
- close(netlink_control_pipe[1]);
- netlink_control_pipe[0] = -1;
- netlink_control_pipe[1] = -1;
-err_close_socket:
- close(linux_netlink_socket);
- linux_netlink_socket = -1;
-err:
- return LIBUSB_ERROR_OTHER;
-}
-
-int linux_netlink_stop_event_monitor(void)
-{
- char dummy = 1;
- ssize_t r;
-
- assert(linux_netlink_socket != -1);
-
- /* Write some dummy data to the control pipe and
- * wait for the thread to exit */
- r = write(netlink_control_pipe[1], &dummy, sizeof(dummy));
- if (r <= 0)
- usbi_warn(NULL, "netlink control pipe signal failed");
-
- pthread_join(libusb_linux_event_thread, NULL);
-
- close(linux_netlink_socket);
- linux_netlink_socket = -1;
-
- /* close and reset control pipe */
- close(netlink_control_pipe[0]);
- close(netlink_control_pipe[1]);
- netlink_control_pipe[0] = -1;
- netlink_control_pipe[1] = -1;
-
- return LIBUSB_SUCCESS;
-}
-
-static const char *netlink_message_parse(const char *buffer, size_t len, const char *key)
-{
- const char *end = buffer + len;
- size_t keylen = strlen(key);
-
- while (buffer < end && *buffer) {
- if (strncmp(buffer, key, keylen) == 0 && buffer[keylen] == '=')
- return buffer + keylen + 1;
- buffer += strlen(buffer) + 1;
- }
-
- return NULL;
-}
-
-/* parse parts of netlink message common to both libudev and the kernel */
-static int linux_netlink_parse(const char *buffer, size_t len, int *detached,
- const char **sys_name, uint8_t *busnum, uint8_t *devaddr)
-{
- const char *tmp, *slash;
-
- errno = 0;
-
- *sys_name = NULL;
- *detached = 0;
- *busnum = 0;
- *devaddr = 0;
-
- tmp = netlink_message_parse(buffer, len, "ACTION");
- if (!tmp) {
- return -1;
- } else if (strcmp(tmp, "remove") == 0) {
- *detached = 1;
- } else if (strcmp(tmp, "add") != 0) {
- usbi_dbg("unknown device action %s", tmp);
- return -1;
- }
-
- /* check that this is a usb message */
- tmp = netlink_message_parse(buffer, len, "SUBSYSTEM");
- if (!tmp || strcmp(tmp, "usb") != 0) {
- /* not usb. ignore */
- return -1;
- }
-
- /* check that this is an actual usb device */
- tmp = netlink_message_parse(buffer, len, "DEVTYPE");
- if (!tmp || strcmp(tmp, "usb_device") != 0) {
- /* not usb. ignore */
- return -1;
- }
-
- tmp = netlink_message_parse(buffer, len, "BUSNUM");
- if (tmp) {
- *busnum = (uint8_t)(strtoul(tmp, NULL, 10) & 0xff);
- if (errno) {
- errno = 0;
- return -1;
- }
-
- tmp = netlink_message_parse(buffer, len, "DEVNUM");
- if (NULL == tmp)
- return -1;
-
- *devaddr = (uint8_t)(strtoul(tmp, NULL, 10) & 0xff);
- if (errno) {
- errno = 0;
- return -1;
- }
- } else {
- /* no bus number. try "DEVICE" */
- tmp = netlink_message_parse(buffer, len, "DEVICE");
- if (!tmp) {
- /* not usb. ignore */
- return -1;
- }
-
- /* Parse a device path such as /dev/bus/usb/003/004 */
- slash = strrchr(tmp, '/');
- if (!slash)
- return -1;
-
- *busnum = (uint8_t)(strtoul(slash - 3, NULL, 10) & 0xff);
- if (errno) {
- errno = 0;
- return -1;
- }
-
- *devaddr = (uint8_t)(strtoul(slash + 1, NULL, 10) & 0xff);
- if (errno) {
- errno = 0;
- return -1;
- }
-
- return 0;
- }
-
- tmp = netlink_message_parse(buffer, len, "DEVPATH");
- if (!tmp)
- return -1;
-
- slash = strrchr(tmp, '/');
- if (slash)
- *sys_name = slash + 1;
-
- /* found a usb device */
- return 0;
-}
-
-static int linux_netlink_read_message(void)
-{
- char cred_buffer[CMSG_SPACE(sizeof(struct ucred))];
- char msg_buffer[2048];
- const char *sys_name = NULL;
- uint8_t busnum, devaddr;
- int detached, r;
- ssize_t len;
- struct cmsghdr *cmsg;
- struct ucred *cred;
- struct sockaddr_nl sa_nl;
- struct iovec iov = { .iov_base = msg_buffer, .iov_len = sizeof(msg_buffer) };
- struct msghdr msg = {
- .msg_iov = &iov, .msg_iovlen = 1,
- .msg_control = cred_buffer, .msg_controllen = sizeof(cred_buffer),
- .msg_name = &sa_nl, .msg_namelen = sizeof(sa_nl)
- };
-
- /* read netlink message */
- len = recvmsg(linux_netlink_socket, &msg, 0);
- if (len == -1) {
- if (errno != EAGAIN && errno != EINTR)
- usbi_err(NULL, "error receiving message from netlink (%d)", errno);
- return -1;
- }
-
- if (len < 32 || (msg.msg_flags & MSG_TRUNC)) {
- usbi_err(NULL, "invalid netlink message length");
- return -1;
- }
-
- if (sa_nl.nl_groups != NL_GROUP_KERNEL || sa_nl.nl_pid != 0) {
- usbi_dbg("ignoring netlink message from unknown group/PID (%u/%u)",
- (unsigned int)sa_nl.nl_groups, (unsigned int)sa_nl.nl_pid);
- return -1;
- }
-
- cmsg = CMSG_FIRSTHDR(&msg);
- if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) {
- usbi_dbg("ignoring netlink message with no sender credentials");
- return -1;
- }
-
- cred = (struct ucred *)CMSG_DATA(cmsg);
- if (cred->uid != 0) {
- usbi_dbg("ignoring netlink message with non-zero sender UID %u", (unsigned int)cred->uid);
- return -1;
- }
-
- r = linux_netlink_parse(msg_buffer, (size_t)len, &detached, &sys_name, &busnum, &devaddr);
- if (r)
- return r;
-
- usbi_dbg("netlink hotplug found device busnum: %hhu, devaddr: %hhu, sys_name: %s, removed: %s",
- busnum, devaddr, sys_name, detached ? "yes" : "no");
-
- /* signal device is available (or not) to all contexts */
- if (detached)
- linux_device_disconnected(busnum, devaddr);
- else
- linux_hotplug_enumerate(busnum, devaddr, sys_name);
-
- return 0;
-}
-
-static void *linux_netlink_event_thread_main(void *arg)
-{
- char dummy;
- int r;
- ssize_t nb;
- struct pollfd fds[] = {
- { .fd = netlink_control_pipe[0],
- .events = POLLIN },
- { .fd = linux_netlink_socket,
- .events = POLLIN },
- };
-
- UNUSED(arg);
-
- usbi_dbg("netlink event thread entering");
-
- while ((r = poll(fds, 2, -1)) >= 0 || errno == EINTR) {
- if (r < 0) {
- /* temporary failure */
- continue;
- }
- if (fds[0].revents & POLLIN) {
- /* activity on control pipe, read the byte and exit */
- nb = read(netlink_control_pipe[0], &dummy, sizeof(dummy));
- if (nb <= 0)
- usbi_warn(NULL, "netlink control pipe read failed");
- break;
- }
- if (fds[1].revents & POLLIN) {
- usbi_mutex_static_lock(&linux_hotplug_lock);
- linux_netlink_read_message();
- usbi_mutex_static_unlock(&linux_hotplug_lock);
- }
- }
-
- usbi_dbg("netlink event thread exiting");
-
- return NULL;
-}
-
-void linux_netlink_hotplug_poll(void)
-{
- int r;
-
- usbi_mutex_static_lock(&linux_hotplug_lock);
- do {
- r = linux_netlink_read_message();
- } while (r == 0);
- usbi_mutex_static_unlock(&linux_hotplug_lock);
-}
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