1 /* -*- Mode: C; c-basic-offset:8 ; indent-tabs-mode:t -*- */
2 /*
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>
7 *
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.
12 *
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.
17 *
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
21 */
22
23 #include "libusbi.h"
24 #include "linux_usbfs.h"
25
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <libudev.h>
29 #include <poll.h>
30 #include <pthread.h>
31 #include <string.h>
32 #include <unistd.h>
33
34 /* udev context */
35 static struct udev *udev_ctx = NULL;
36 static int udev_monitor_fd = -1;
37 static usbi_event_t udev_control_event = USBI_INVALID_EVENT;
38 static struct udev_monitor *udev_monitor = NULL;
39 static pthread_t linux_event_thread;
40
41 static void udev_hotplug_event(struct udev_device *udev_dev);
42 static void *linux_udev_event_thread_main(void *arg);
43
linux_udev_start_event_monitor(void)44 int linux_udev_start_event_monitor(void)
45 {
46 int r;
47
48 assert(udev_ctx == NULL);
49 udev_ctx = udev_new();
50 if (!udev_ctx) {
51 usbi_err(NULL, "could not create udev context");
52 goto err;
53 }
54
55 udev_monitor = udev_monitor_new_from_netlink(udev_ctx, "udev");
56 if (!udev_monitor) {
57 usbi_err(NULL, "could not initialize udev monitor");
58 goto err_free_ctx;
59 }
60
61 r = udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "usb", "usb_device");
62 if (r) {
63 usbi_err(NULL, "could not initialize udev monitor filter for \"usb\" subsystem");
64 goto err_free_monitor;
65 }
66
67 if (udev_monitor_enable_receiving(udev_monitor)) {
68 usbi_err(NULL, "failed to enable the udev monitor");
69 goto err_free_monitor;
70 }
71
72 udev_monitor_fd = udev_monitor_get_fd(udev_monitor);
73
74 #if defined(FD_CLOEXEC)
75 /* Make sure the udev file descriptor is marked as CLOEXEC */
76 r = fcntl(udev_monitor_fd, F_GETFD);
77 if (r == -1) {
78 usbi_err(NULL, "failed to get udev monitor fd flags, errno=%d", errno);
79 goto err_free_monitor;
80 }
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;
85 }
86 }
87 #endif
88
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);
92 if (r == -1) {
93 usbi_err(NULL, "failed to get udev monitor fd status flags, errno=%d", errno);
94 goto err_free_monitor;
95 }
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;
100 }
101 }
102
103 r = usbi_create_event(&udev_control_event);
104 if (r) {
105 usbi_err(NULL, "failed to create udev control event");
106 goto err_free_monitor;
107 }
108
109 r = pthread_create(&linux_event_thread, NULL, linux_udev_event_thread_main, NULL);
110 if (r) {
111 usbi_err(NULL, "failed to create hotplug event thread (%d)", r);
112 goto err_destroy_event;
113 }
114
115 return LIBUSB_SUCCESS;
116
117 err_destroy_event:
118 usbi_destroy_event(&udev_control_event);
119 udev_control_event = (usbi_event_t)USBI_INVALID_EVENT;
120 err_free_monitor:
121 udev_monitor_unref(udev_monitor);
122 udev_monitor = NULL;
123 udev_monitor_fd = -1;
124 err_free_ctx:
125 udev_unref(udev_ctx);
126 err:
127 udev_ctx = NULL;
128 return LIBUSB_ERROR_OTHER;
129 }
130
linux_udev_stop_event_monitor(void)131 int linux_udev_stop_event_monitor(void)
132 {
133 int r;
134
135 assert(udev_ctx != NULL);
136 assert(udev_monitor != NULL);
137 assert(udev_monitor_fd != -1);
138
139 /* Signal the control event and wait for the thread to exit */
140 usbi_signal_event(&udev_control_event);
141
142 r = pthread_join(linux_event_thread, NULL);
143 if (r)
144 usbi_warn(NULL, "failed to join hotplug event thread (%d)", r);
145
146 usbi_destroy_event(&udev_control_event);
147 udev_control_event = (usbi_event_t)USBI_INVALID_EVENT;
148
149 /* Release the udev monitor */
150 udev_monitor_unref(udev_monitor);
151 udev_monitor = NULL;
152 udev_monitor_fd = -1;
153
154 /* Clean up the udev context */
155 udev_unref(udev_ctx);
156 udev_ctx = NULL;
157
158 return LIBUSB_SUCCESS;
159 }
160
linux_udev_event_thread_main(void * arg)161 static void *linux_udev_event_thread_main(void *arg)
162 {
163 struct pollfd fds[] = {
164 { .fd = USBI_EVENT_OS_HANDLE(&udev_control_event),
165 .events = USBI_EVENT_POLL_EVENTS },
166 { .fd = udev_monitor_fd,
167 .events = POLLIN },
168 };
169 struct udev_device *udev_dev;
170 int r;
171
172 UNUSED(arg);
173
174 #if defined(HAVE_PTHREAD_SETNAME_NP)
175 r = pthread_setname_np(pthread_self(), "libusb_event");
176 if (r)
177 usbi_warn(NULL, "failed to set hotplug event thread name, error=%d", r);
178 #endif
179
180 usbi_dbg("udev event thread entering");
181
182 while (1) {
183 r = poll(fds, 2, -1);
184 if (r == -1) {
185 /* check for temporary failure */
186 if (errno == EINTR)
187 continue;
188 usbi_err(NULL, "poll() failed, errno=%d", errno);
189 break;
190 }
191 if (fds[0].revents) {
192 /* activity on control event, exit */
193 break;
194 }
195 if (fds[1].revents) {
196 usbi_mutex_static_lock(&linux_hotplug_lock);
197 udev_dev = udev_monitor_receive_device(udev_monitor);
198 if (udev_dev)
199 udev_hotplug_event(udev_dev);
200 usbi_mutex_static_unlock(&linux_hotplug_lock);
201 }
202 }
203
204 usbi_dbg("udev event thread exiting");
205
206 return NULL;
207 }
208
udev_device_info(struct libusb_context * ctx,int detached,struct udev_device * udev_dev,uint8_t * busnum,uint8_t * devaddr,const char ** sys_name)209 static int udev_device_info(struct libusb_context *ctx, int detached,
210 struct udev_device *udev_dev, uint8_t *busnum,
211 uint8_t *devaddr, const char **sys_name) {
212 const char *dev_node;
213
214 dev_node = udev_device_get_devnode(udev_dev);
215 if (!dev_node) {
216 return LIBUSB_ERROR_OTHER;
217 }
218
219 *sys_name = udev_device_get_sysname(udev_dev);
220 if (!*sys_name) {
221 return LIBUSB_ERROR_OTHER;
222 }
223
224 return linux_get_device_address(ctx, detached, busnum, devaddr,
225 dev_node, *sys_name, -1);
226 }
227
udev_hotplug_event(struct udev_device * udev_dev)228 static void udev_hotplug_event(struct udev_device *udev_dev)
229 {
230 const char *udev_action;
231 const char *sys_name = NULL;
232 uint8_t busnum = 0, devaddr = 0;
233 int detached;
234 int r;
235
236 do {
237 udev_action = udev_device_get_action(udev_dev);
238 if (!udev_action) {
239 break;
240 }
241
242 detached = !strncmp(udev_action, "remove", 6);
243
244 r = udev_device_info(NULL, detached, udev_dev, &busnum, &devaddr, &sys_name);
245 if (LIBUSB_SUCCESS != r) {
246 break;
247 }
248
249 usbi_dbg("udev hotplug event. action: %s.", udev_action);
250
251 if (strncmp(udev_action, "add", 3) == 0) {
252 linux_hotplug_enumerate(busnum, devaddr, sys_name);
253 } else if (detached) {
254 linux_device_disconnected(busnum, devaddr);
255 } else if (strncmp(udev_action, "bind", 4) == 0) {
256 /* silently ignore "known unhandled" action */
257 } else {
258 usbi_err(NULL, "ignoring udev action %s", udev_action);
259 }
260 } while (0);
261
262 udev_device_unref(udev_dev);
263 }
264
linux_udev_scan_devices(struct libusb_context * ctx)265 int linux_udev_scan_devices(struct libusb_context *ctx)
266 {
267 struct udev_enumerate *enumerator;
268 struct udev_list_entry *devices, *entry;
269 struct udev_device *udev_dev;
270 const char *sys_name;
271 int r;
272
273 assert(udev_ctx != NULL);
274
275 enumerator = udev_enumerate_new(udev_ctx);
276 if (NULL == enumerator) {
277 usbi_err(ctx, "error creating udev enumerator");
278 return LIBUSB_ERROR_OTHER;
279 }
280
281 udev_enumerate_add_match_subsystem(enumerator, "usb");
282 udev_enumerate_add_match_property(enumerator, "DEVTYPE", "usb_device");
283 udev_enumerate_scan_devices(enumerator);
284 devices = udev_enumerate_get_list_entry(enumerator);
285
286 entry = NULL;
287 udev_list_entry_foreach(entry, devices) {
288 const char *path = udev_list_entry_get_name(entry);
289 uint8_t busnum = 0, devaddr = 0;
290
291 udev_dev = udev_device_new_from_syspath(udev_ctx, path);
292
293 r = udev_device_info(ctx, 0, udev_dev, &busnum, &devaddr, &sys_name);
294 if (r) {
295 udev_device_unref(udev_dev);
296 continue;
297 }
298
299 linux_enumerate_device(ctx, busnum, devaddr, sys_name);
300 udev_device_unref(udev_dev);
301 }
302
303 udev_enumerate_unref(enumerator);
304
305 return LIBUSB_SUCCESS;
306 }
307
linux_udev_hotplug_poll(void)308 void linux_udev_hotplug_poll(void)
309 {
310 struct udev_device *udev_dev;
311
312 usbi_mutex_static_lock(&linux_hotplug_lock);
313 do {
314 udev_dev = udev_monitor_receive_device(udev_monitor);
315 if (udev_dev) {
316 usbi_dbg("Handling hotplug event from hotplug_poll");
317 udev_hotplug_event(udev_dev);
318 }
319 } while (udev_dev);
320 usbi_mutex_static_unlock(&linux_hotplug_lock);
321 }
322