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) 2012-2013 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
24 #include "linux_usbfs.h"
35 static struct udev *udev_ctx = NULL;
36 static int udev_monitor_fd = -1;
37 static int udev_control_pipe[2] = {-1, -1};
38 static struct udev_monitor *udev_monitor = NULL;
39 static pthread_t linux_event_thread;
41 static void udev_hotplug_event(struct udev_device* udev_dev);
42 static void *linux_udev_event_thread_main(void *arg);
44 int linux_udev_start_event_monitor(void)
48 assert(udev_ctx == NULL);
49 udev_ctx = udev_new();
51 usbi_err(NULL, "could not create udev context");
55 udev_monitor = udev_monitor_new_from_netlink(udev_ctx, "udev");
57 usbi_err(NULL, "could not initialize udev monitor");
61 r = udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "usb", "usb_device");
63 usbi_err(NULL, "could not initialize udev monitor filter for \"usb\" subsystem");
64 goto err_free_monitor;
67 if (udev_monitor_enable_receiving(udev_monitor)) {
68 usbi_err(NULL, "failed to enable the udev monitor");
69 goto err_free_monitor;
72 udev_monitor_fd = udev_monitor_get_fd(udev_monitor);
74 #if defined(FD_CLOEXEC)
75 /* Make sure the udev file descriptor is marked as CLOEXEC */
76 r = fcntl(udev_monitor_fd, F_GETFD);
78 usbi_err(NULL, "failed to get udev monitor fd flags, errno=%d", errno);
79 goto err_free_monitor;
81 if (!(r & FD_CLOEXEC)) {
82 if (fcntl(udev_monitor_fd, F_SETFD, r | FD_CLOEXEC) == -1) {
83 usbi_err(NULL, "failed to set udev monitor fd flags, errno=%d", errno);
84 goto err_free_monitor;
89 /* Some older versions of udev are not non-blocking by default,
90 * so make sure this is set */
91 r = fcntl(udev_monitor_fd, F_GETFL);
93 usbi_err(NULL, "failed to get udev monitor fd status flags, errno=%d", errno);
94 goto err_free_monitor;
96 if (!(r & O_NONBLOCK)) {
97 if (fcntl(udev_monitor_fd, F_SETFL, r | O_NONBLOCK) == -1) {
98 usbi_err(NULL, "failed to set udev monitor fd status flags, errno=%d", errno);
99 goto err_free_monitor;
103 r = usbi_pipe(udev_control_pipe);
105 usbi_err(NULL, "could not create udev control pipe");
106 goto err_free_monitor;
109 r = pthread_create(&linux_event_thread, NULL, linux_udev_event_thread_main, NULL);
111 usbi_err(NULL, "creating hotplug event thread (%d)", r);
115 return LIBUSB_SUCCESS;
118 close(udev_control_pipe[0]);
119 close(udev_control_pipe[1]);
121 udev_monitor_unref(udev_monitor);
123 udev_monitor_fd = -1;
125 udev_unref(udev_ctx);
128 return LIBUSB_ERROR_OTHER;
131 int linux_udev_stop_event_monitor(void)
136 assert(udev_ctx != NULL);
137 assert(udev_monitor != NULL);
138 assert(udev_monitor_fd != -1);
140 /* Write some dummy data to the control pipe and
141 * wait for the thread to exit */
142 r = write(udev_control_pipe[1], &dummy, sizeof(dummy));
144 usbi_warn(NULL, "udev control pipe signal failed");
146 pthread_join(linux_event_thread, NULL);
148 /* Release the udev monitor */
149 udev_monitor_unref(udev_monitor);
151 udev_monitor_fd = -1;
153 /* Clean up the udev context */
154 udev_unref(udev_ctx);
157 /* close and reset control pipe */
158 close(udev_control_pipe[0]);
159 close(udev_control_pipe[1]);
160 udev_control_pipe[0] = -1;
161 udev_control_pipe[1] = -1;
163 return LIBUSB_SUCCESS;
166 static void *linux_udev_event_thread_main(void *arg)
171 struct udev_device* udev_dev;
172 struct pollfd fds[] = {
173 {.fd = udev_control_pipe[0],
175 {.fd = udev_monitor_fd,
179 usbi_dbg("udev event thread entering.");
181 while ((r = poll(fds, 2, -1)) >= 0 || errno == EINTR) {
183 /* temporary failure */
186 if (fds[0].revents & POLLIN) {
187 /* activity on control pipe, read the byte and exit */
188 nb = read(udev_control_pipe[0], &dummy, sizeof(dummy));
190 usbi_warn(NULL, "udev control pipe read failed");
194 if (fds[1].revents & POLLIN) {
195 usbi_mutex_static_lock(&linux_hotplug_lock);
196 udev_dev = udev_monitor_receive_device(udev_monitor);
198 udev_hotplug_event(udev_dev);
199 usbi_mutex_static_unlock(&linux_hotplug_lock);
203 usbi_dbg("udev event thread exiting");
208 static int udev_device_info(struct libusb_context *ctx, int detached,
209 struct udev_device *udev_dev, uint8_t *busnum,
210 uint8_t *devaddr, const char **sys_name) {
211 const char *dev_node;
213 dev_node = udev_device_get_devnode(udev_dev);
215 return LIBUSB_ERROR_OTHER;
218 *sys_name = udev_device_get_sysname(udev_dev);
220 return LIBUSB_ERROR_OTHER;
223 return linux_get_device_address(ctx, detached, busnum, devaddr,
224 dev_node, *sys_name, -1);
227 static void udev_hotplug_event(struct udev_device* udev_dev)
229 const char* udev_action;
230 const char* sys_name = NULL;
231 uint8_t busnum = 0, devaddr = 0;
236 udev_action = udev_device_get_action(udev_dev);
241 detached = !strncmp(udev_action, "remove", 6);
243 r = udev_device_info(NULL, detached, udev_dev, &busnum, &devaddr, &sys_name);
244 if (LIBUSB_SUCCESS != r) {
248 usbi_dbg("udev hotplug event. action: %s.", udev_action);
250 if (strncmp(udev_action, "add", 3) == 0) {
251 linux_hotplug_enumerate(busnum, devaddr, sys_name);
252 } else if (detached) {
253 linux_device_disconnected(busnum, devaddr);
254 } else if (strncmp(udev_action, "bind", 4) == 0) {
255 /* silently ignore "known unhandled" action */
257 usbi_err(NULL, "ignoring udev action %s", udev_action);
261 udev_device_unref(udev_dev);
264 int linux_udev_scan_devices(struct libusb_context *ctx)
266 struct udev_enumerate *enumerator;
267 struct udev_list_entry *devices, *entry;
268 struct udev_device *udev_dev;
269 const char *sys_name;
272 assert(udev_ctx != NULL);
274 enumerator = udev_enumerate_new(udev_ctx);
275 if (NULL == enumerator) {
276 usbi_err(ctx, "error creating udev enumerator");
277 return LIBUSB_ERROR_OTHER;
280 udev_enumerate_add_match_subsystem(enumerator, "usb");
281 udev_enumerate_add_match_property(enumerator, "DEVTYPE", "usb_device");
282 udev_enumerate_scan_devices(enumerator);
283 devices = udev_enumerate_get_list_entry(enumerator);
286 udev_list_entry_foreach(entry, devices) {
287 const char *path = udev_list_entry_get_name(entry);
288 uint8_t busnum = 0, devaddr = 0;
290 udev_dev = udev_device_new_from_syspath(udev_ctx, path);
292 r = udev_device_info(ctx, 0, udev_dev, &busnum, &devaddr, &sys_name);
294 udev_device_unref(udev_dev);
298 linux_enumerate_device(ctx, busnum, devaddr, sys_name);
299 udev_device_unref(udev_dev);
302 udev_enumerate_unref(enumerator);
304 return LIBUSB_SUCCESS;
307 void linux_udev_hotplug_poll(void)
309 struct udev_device* udev_dev;
311 usbi_mutex_static_lock(&linux_hotplug_lock);
313 udev_dev = udev_monitor_receive_device(udev_monitor);
315 usbi_dbg("Handling hotplug event from hotplug_poll");
316 udev_hotplug_event(udev_dev);
319 usbi_mutex_static_unlock(&linux_hotplug_lock);