/* -*- Mode: C; c-basic-offset:8 ; indent-tabs-mode:t -*- */
/*
* Linux usbfs backend for libusb
* Copyright (C) 2007-2009 Daniel Drake <[email protected]>
* Copyright (c) 2001 Johannes Erdfelt <[email protected]>
* Copyright (c) 2013 Nathan Hjelm <[email protected]>
*
* 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 "libusb.h"
#include "libusbi.h"
#include "linux_usbfs.h"
#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#ifdef HAVE_ASM_TYPES_H
#include <asm/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#include <arpa/inet.h>
#ifdef HAVE_LINUX_NETLINK_H
#include <linux/netlink.h>
#endif
#ifdef HAVE_LINUX_FILTER_H
#include <linux/filter.h>
#endif
#define KERNEL 1
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);
struct sockaddr_nl snl = { .nl_family=AF_NETLINK, .nl_groups=KERNEL };
static int set_fd_cloexec_nb (int fd)
{
int flags;
#if defined(FD_CLOEXEC)
flags = fcntl (linux_netlink_socket, F_GETFD);
if (0 > flags) {
return -1;
}
if (!(flags & FD_CLOEXEC)) {
fcntl (linux_netlink_socket, F_SETFD, flags | FD_CLOEXEC);
}
#endif
flags = fcntl (linux_netlink_socket, F_GETFL);
if (0 > flags) {
return -1;
}
if (!(flags & O_NONBLOCK)) {
fcntl (linux_netlink_socket, F_SETFL, flags | O_NONBLOCK);
}
return 0;
}
int linux_netlink_start_event_monitor(void)
{
int socktype = SOCK_RAW;
int ret;
snl.nl_groups = KERNEL;
#if defined(SOCK_CLOEXEC)
socktype |= SOCK_CLOEXEC;
#endif
#if defined(SOCK_NONBLOCK)
socktype |= SOCK_NONBLOCK;
#endif
linux_netlink_socket = socket(PF_NETLINK, socktype, NETLINK_KOBJECT_UEVENT);
if (-1 == linux_netlink_socket && EINVAL == errno) {
linux_netlink_socket = socket(PF_NETLINK, SOCK_RAW, NETLINK_KOBJECT_UEVENT);
}
if (-1 == linux_netlink_socket) {
return LIBUSB_ERROR_OTHER;
}
ret = set_fd_cloexec_nb (linux_netlink_socket);
if (0 != ret) {
close (linux_netlink_socket);
linux_netlink_socket = -1;
return LIBUSB_ERROR_OTHER;
}
ret = bind(linux_netlink_socket, (struct sockaddr *) &snl, sizeof(snl));
if (0 != ret) {
close(linux_netlink_socket);
return LIBUSB_ERROR_OTHER;
}
/* TODO -- add authentication */
/* setsockopt(linux_netlink_socket, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)); */
ret = usbi_pipe(netlink_control_pipe);
if (ret) {
usbi_err(NULL, "could not create netlink control pipe");
close(linux_netlink_socket);
return LIBUSB_ERROR_OTHER;
}
ret = pthread_create(&libusb_linux_event_thread, NULL, linux_netlink_event_thread_main, NULL);
if (0 != ret) {
close(netlink_control_pipe[0]);
close(netlink_control_pipe[1]);
close(linux_netlink_socket);
return LIBUSB_ERROR_OTHER;
}
return LIBUSB_SUCCESS;
}
int linux_netlink_stop_event_monitor(void)
{
int r;
char dummy = 1;
if (-1 == linux_netlink_socket) {
/* already closed. nothing to do */
return LIBUSB_SUCCESS;
}
/* Write some dummy data to the control pipe and
* wait for the thread to exit */
r = usbi_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)
{
size_t keylen = strlen(key);
size_t offset;
for (offset = 0 ; offset < len && '\0' != buffer[offset] ; offset += strlen(buffer + offset) + 1) {
if (0 == strncmp(buffer + offset, key, keylen) &&
'=' == buffer[offset + keylen]) {
return buffer + offset + keylen + 1;
}
}
return NULL;
}
/* parse parts of netlink message common to both libudev and the kernel */
static int linux_netlink_parse(char *buffer, size_t len, int *detached, const char **sys_name,
uint8_t *busnum, uint8_t *devaddr) {
const char *tmp;
int i;
errno = 0;
*sys_name = NULL;
*detached = 0;
*busnum = 0;
*devaddr = 0;
tmp = netlink_message_parse((const char *) buffer, len, "ACTION");
if (tmp == NULL)
return -1;
if (0 == strcmp(tmp, "remove")) {
*detached = 1;
} else if (0 != strcmp(tmp, "add")) {
usbi_dbg("unknown device action %s", tmp);
return -1;
}
/* check that this is a usb message */
tmp = netlink_message_parse(buffer, len, "SUBSYSTEM");
if (NULL == tmp || 0 != strcmp(tmp, "usb")) {
/* not usb. ignore */
return -1;
}
tmp = netlink_message_parse(buffer, len, "BUSNUM");
if (NULL == tmp) {
/* no bus number (likely a usb interface). ignore*/
return -1;
}
*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;
}
tmp = netlink_message_parse(buffer, len, "DEVPATH");
if (NULL == tmp) {
return -1;
}
for (i = strlen(tmp) - 1 ; i ; --i) {
if ('/' ==tmp[i]) {
*sys_name = tmp + i + 1;
break;
}
}
/* found a usb device */
return 0;
}
static int linux_netlink_read_message(void)
{
unsigned char buffer[1024];
struct iovec iov = {.iov_base = buffer, .iov_len = sizeof(buffer)};
struct msghdr meh = { .msg_iov=&iov, .msg_iovlen=1,
.msg_name=&snl, .msg_namelen=sizeof(snl) };
const char *sys_name = NULL;
uint8_t busnum, devaddr;
int detached, r;
size_t len;
/* read netlink message */
memset(buffer, 0, sizeof(buffer));
len = recvmsg(linux_netlink_socket, &meh, 0);
if (len < 32) {
if (errno != EAGAIN)
usbi_dbg("error recieving message from netlink");
return -1;
}
/* TODO -- authenticate this message is from the kernel or udevd */
r = linux_netlink_parse(buffer, 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, sys_name);
else
linux_hotplug_enumerate(busnum, devaddr, sys_name);
return 0;
}
static void *linux_netlink_event_thread_main(void *arg)
{
char dummy;
int r;
struct pollfd fds[] = {
{ .fd = netlink_control_pipe[0],
.events = POLLIN },
{ .fd = linux_netlink_socket,
.events = POLLIN },
};
/* silence compiler warning */
(void) arg;
while (poll(fds, 2, -1) >= 0) {
if (fds[0].revents & POLLIN) {
/* activity on control pipe, read the byte and exit */
r = usbi_read(netlink_control_pipe[0], &dummy, sizeof(dummy));
if (r <= 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);
}
}
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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