1 /* -*- Mode: C; c-basic-offset:8 ; indent-tabs-mode:t -*- */
3 * Linux usbfs backend for libusb
4 * Copyright (C) 2007-2009 Daniel Drake <dsd@gentoo.org>
5 * Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com>
6 * Copyright (c) 2013 Nathan Hjelm <hjelmn@mac.com>
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26 #include "linux_usbfs.h"
36 #include <sys/types.h>
38 #ifdef HAVE_ASM_TYPES_H
39 #include <asm/types.h>
42 #ifdef HAVE_SYS_SOCKET_H
43 #include <sys/socket.h>
46 #include <arpa/inet.h>
48 #ifdef HAVE_LINUX_NETLINK_H
49 #include <linux/netlink.h>
52 #ifdef HAVE_LINUX_FILTER_H
53 #include <linux/filter.h>
58 static int linux_netlink_socket = -1;
59 static int netlink_control_pipe[2] = { -1, -1 };
60 static pthread_t libusb_linux_event_thread;
62 static void *linux_netlink_event_thread_main(void *arg);
64 struct sockaddr_nl snl = { .nl_family=AF_NETLINK, .nl_groups=KERNEL };
66 static int set_fd_cloexec_nb (int fd)
70 #if defined(FD_CLOEXEC)
71 fcntl (linux_netlink_socket, F_GETFD, &flags);
73 if (!(flags & FD_CLOEXEC)) {
74 fcntl (linux_netlink_socket, F_SETFD, flags | FD_CLOEXEC);
78 fcntl (linux_netlink_socket, F_GETFL, &flags);
79 if (!(flags & O_NONBLOCK)) {
80 fcntl (linux_netlink_socket, F_SETFL, flags | O_NONBLOCK);
86 int linux_netlink_start_event_monitor(void)
88 int socktype = SOCK_RAW;
91 snl.nl_groups = KERNEL;
93 #if defined(SOCK_CLOEXEC)
94 socktype |= SOCK_CLOEXEC;
96 #if defined(SOCK_NONBLOCK)
97 socktype |= SOCK_NONBLOCK;
100 linux_netlink_socket = socket(PF_NETLINK, socktype, NETLINK_KOBJECT_UEVENT);
101 if (-1 == linux_netlink_socket && EINVAL == errno) {
102 linux_netlink_socket = socket(PF_NETLINK, SOCK_RAW, NETLINK_KOBJECT_UEVENT);
105 if (-1 == linux_netlink_socket) {
106 return LIBUSB_ERROR_OTHER;
109 ret = set_fd_cloexec_nb (linux_netlink_socket);
111 close (linux_netlink_socket);
112 linux_netlink_socket = -1;
113 return LIBUSB_ERROR_OTHER;
116 ret = bind(linux_netlink_socket, (struct sockaddr *) &snl, sizeof(snl));
118 close(linux_netlink_socket);
119 return LIBUSB_ERROR_OTHER;
122 /* TODO -- add authentication */
123 /* setsockopt(linux_netlink_socket, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)); */
125 ret = usbi_pipe(netlink_control_pipe);
127 usbi_err(NULL, "could not create netlink control pipe");
128 close(linux_netlink_socket);
129 return LIBUSB_ERROR_OTHER;
132 ret = pthread_create(&libusb_linux_event_thread, NULL, linux_netlink_event_thread_main, NULL);
134 close(netlink_control_pipe[0]);
135 close(netlink_control_pipe[1]);
136 close(linux_netlink_socket);
137 return LIBUSB_ERROR_OTHER;
140 return LIBUSB_SUCCESS;
143 int linux_netlink_stop_event_monitor(void)
148 if (-1 == linux_netlink_socket) {
149 /* already closed. nothing to do */
150 return LIBUSB_SUCCESS;
153 /* Write some dummy data to the control pipe and
154 * wait for the thread to exit */
155 r = usbi_write(netlink_control_pipe[1], &dummy, sizeof(dummy));
157 usbi_warn(NULL, "netlink control pipe signal failed");
159 pthread_join(libusb_linux_event_thread, NULL);
161 close(linux_netlink_socket);
162 linux_netlink_socket = -1;
164 /* close and reset control pipe */
165 close(netlink_control_pipe[0]);
166 close(netlink_control_pipe[1]);
167 netlink_control_pipe[0] = -1;
168 netlink_control_pipe[1] = -1;
170 return LIBUSB_SUCCESS;
173 static const char *netlink_message_parse (const char *buffer, size_t len, const char *key)
175 size_t keylen = strlen(key);
178 for (offset = 0 ; offset < len && '\0' != buffer[offset] ; offset += strlen(buffer + offset) + 1) {
179 if (0 == strncmp(buffer + offset, key, keylen) &&
180 '=' == buffer[offset + keylen]) {
181 return buffer + offset + keylen + 1;
188 /* parse parts of netlink message common to both libudev and the kernel */
189 static int linux_netlink_parse(char *buffer, size_t len, int *detached, const char **sys_name,
190 uint8_t *busnum, uint8_t *devaddr) {
201 tmp = netlink_message_parse((const char *) buffer, len, "ACTION");
204 if (0 == strcmp(tmp, "remove")) {
206 } else if (0 != strcmp(tmp, "add")) {
207 usbi_dbg("unknown device action %s", tmp);
211 /* check that this is a usb message */
212 tmp = netlink_message_parse(buffer, len, "SUBSYSTEM");
213 if (NULL == tmp || 0 != strcmp(tmp, "usb")) {
214 /* not usb. ignore */
218 tmp = netlink_message_parse(buffer, len, "BUSNUM");
220 /* no bus number (likely a usb interface). ignore*/
224 *busnum = (uint8_t)(strtoul(tmp, NULL, 10) & 0xff);
230 tmp = netlink_message_parse(buffer, len, "DEVNUM");
235 *devaddr = (uint8_t)(strtoul(tmp, NULL, 10) & 0xff);
241 tmp = netlink_message_parse(buffer, len, "DEVPATH");
246 for (i = strlen(tmp) - 1 ; i ; --i) {
248 *sys_name = tmp + i + 1;
253 /* found a usb device */
257 static int linux_netlink_read_message(void)
259 unsigned char buffer[1024];
260 struct iovec iov = {.iov_base = buffer, .iov_len = sizeof(buffer)};
261 struct msghdr meh = { .msg_iov=&iov, .msg_iovlen=1,
262 .msg_name=&snl, .msg_namelen=sizeof(snl) };
263 const char *sys_name = NULL;
264 uint8_t busnum, devaddr;
268 /* read netlink message */
269 memset(buffer, 0, sizeof(buffer));
270 len = recvmsg(linux_netlink_socket, &meh, 0);
273 usbi_dbg("error recieving message from netlink");
277 /* TODO -- authenticate this message is from the kernel or udevd */
279 r = linux_netlink_parse(buffer, len, &detached, &sys_name,
284 usbi_dbg("netlink hotplug found device busnum: %hhu, devaddr: %hhu, sys_name: %s, removed: %s",
285 busnum, devaddr, sys_name, detached ? "yes" : "no");
287 /* signal device is available (or not) to all contexts */
289 linux_hotplug_disconnected(busnum, devaddr, sys_name);
291 linux_hotplug_enumerate(busnum, devaddr, sys_name);
296 static void *linux_netlink_event_thread_main(void *arg)
300 struct pollfd fds[] = {
301 { .fd = netlink_control_pipe[0],
303 { .fd = linux_netlink_socket,
307 /* silence compiler warning */
310 while (poll(fds, 2, -1) >= 0) {
311 if (fds[0].revents & POLLIN) {
312 /* activity on control pipe, read the byte and exit */
313 r = usbi_read(netlink_control_pipe[0], &dummy, sizeof(dummy));
315 usbi_warn(NULL, "netlink control pipe read failed");
319 if (fds[1].revents & POLLIN) {
320 usbi_mutex_static_lock(&linux_hotplug_lock);
321 linux_netlink_read_message();
322 usbi_mutex_static_unlock(&linux_hotplug_lock);
329 void linux_netlink_hotplug_poll(void)
333 usbi_mutex_static_lock(&linux_hotplug_lock);
335 r = linux_netlink_read_message();
337 usbi_mutex_static_unlock(&linux_hotplug_lock);