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 "config.h"
24
25#include <assert.h>
26#include <ctype.h>
27#include <dirent.h>
28#include <errno.h>
29#include <fcntl.h>
30#include <poll.h>
31#include <stdio.h>
32#include <stdlib.h>
33#include <string.h>
34#include <sys/ioctl.h>
35#include <sys/stat.h>
36#include <sys/types.h>
37#include <sys/utsname.h>
38#include <sys/socket.h>
39#include <unistd.h>
40#include <libudev.h>
41
42#include "libusb.h"
43#include "libusbi.h"
44#include "linux_usbfs.h"
45
46/* udev context */
47static struct udev *udev_ctx = NULL;
48static int udev_monitor_fd = -1;
49static int udev_control_pipe[2] = {-1, -1};
50static struct udev_monitor *udev_monitor = NULL;
51static pthread_t linux_event_thread;
52
53static void udev_hotplug_event(struct udev_device* udev_dev);
54static void *linux_udev_event_thread_main(void *arg);
55
56int linux_udev_start_event_monitor(void)
57{
58	int r;
59
60	assert(udev_ctx == NULL);
61	udev_ctx = udev_new();
62	if (!udev_ctx) {
63		usbi_err(NULL, "could not create udev context");
64		return LIBUSB_ERROR_OTHER;
65	}
66
67	udev_monitor = udev_monitor_new_from_netlink(udev_ctx, "udev");
68	if (!udev_monitor) {
69		usbi_err(NULL, "could not initialize udev monitor");
70		goto err_free_ctx;
71	}
72
73	r = udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "usb", 0);
74	if (r) {
75		usbi_err(NULL, "could not initialize udev monitor filter for \"usb\" subsystem");
76		goto err_free_monitor;
77	}
78
79	if (udev_monitor_enable_receiving(udev_monitor)) {
80		usbi_err(NULL, "failed to enable the udev monitor");
81		goto err_free_monitor;
82	}
83
84	udev_monitor_fd = udev_monitor_get_fd(udev_monitor);
85
86	/* Some older versions of udev are not non-blocking by default,
87	 * so make sure this is set */
88	r = fcntl(udev_monitor_fd, F_GETFL);
89	if (r == -1) {
90		usbi_err(NULL, "getting udev monitor fd flags (%d)", errno);
91		goto err_free_monitor;
92	}
93	r = fcntl(udev_monitor_fd, F_SETFL, r | O_NONBLOCK);
94	if (r) {
95		usbi_err(NULL, "setting udev monitor fd flags (%d)", errno);
96		goto err_free_monitor;
97	}
98
99	r = usbi_pipe(udev_control_pipe);
100	if (r) {
101		usbi_err(NULL, "could not create udev control pipe");
102		goto err_free_monitor;
103	}
104
105	r = pthread_create(&linux_event_thread, NULL, linux_udev_event_thread_main, NULL);
106	if (r) {
107		usbi_err(NULL, "creating hotplug event thread (%d)", r);
108		goto err_close_pipe;
109	}
110
111	return LIBUSB_SUCCESS;
112
113err_close_pipe:
114	close(udev_control_pipe[0]);
115	close(udev_control_pipe[1]);
116err_free_monitor:
117	udev_monitor_unref(udev_monitor);
118	udev_monitor = NULL;
119	udev_monitor_fd = -1;
120err_free_ctx:
121	udev_unref(udev_ctx);
122	udev_ctx = NULL;
123	return LIBUSB_ERROR_OTHER;
124}
125
126int linux_udev_stop_event_monitor(void)
127{
128	char dummy = 1;
129	int r;
130
131	assert(udev_ctx != NULL);
132	assert(udev_monitor != NULL);
133	assert(udev_monitor_fd != -1);
134
135	/* Write some dummy data to the control pipe and
136	 * wait for the thread to exit */
137	r = usbi_write(udev_control_pipe[1], &dummy, sizeof(dummy));
138	if (r <= 0) {
139		usbi_warn(NULL, "udev control pipe signal failed");
140	}
141	pthread_join(linux_event_thread, NULL);
142
143	/* Release the udev monitor */
144	udev_monitor_unref(udev_monitor);
145	udev_monitor = NULL;
146	udev_monitor_fd = -1;
147
148	/* Clean up the udev context */
149	udev_unref(udev_ctx);
150	udev_ctx = NULL;
151
152	/* close and reset control pipe */
153	close(udev_control_pipe[0]);
154	close(udev_control_pipe[1]);
155	udev_control_pipe[0] = -1;
156	udev_control_pipe[1] = -1;
157
158	return LIBUSB_SUCCESS;
159}
160
161static void *linux_udev_event_thread_main(void *arg)
162{
163	char dummy;
164	int r;
165	struct udev_device* udev_dev;
166	struct pollfd fds[] = {
167		{.fd = udev_control_pipe[0],
168		 .events = POLLIN},
169		{.fd = udev_monitor_fd,
170		 .events = POLLIN},
171	};
172
173	usbi_dbg("udev event thread entering.");
174
175	while (poll(fds, 2, -1) >= 0) {
176		if (fds[0].revents & POLLIN) {
177			/* activity on control pipe, read the byte and exit */
178			r = usbi_read(udev_control_pipe[0], &dummy, sizeof(dummy));
179			if (r <= 0) {
180				usbi_warn(NULL, "udev control pipe read failed");
181			}
182			break;
183		}
184		if (fds[1].revents & POLLIN) {
185			usbi_mutex_static_lock(&linux_hotplug_lock);
186			udev_dev = udev_monitor_receive_device(udev_monitor);
187			if (udev_dev)
188				udev_hotplug_event(udev_dev);
189			usbi_mutex_static_unlock(&linux_hotplug_lock);
190		}
191	}
192
193	usbi_dbg("udev event thread exiting");
194
195	return NULL;
196}
197
198static int udev_device_info(struct libusb_context *ctx, int detached,
199			    struct udev_device *udev_dev, uint8_t *busnum,
200			    uint8_t *devaddr, const char **sys_name) {
201	const char *dev_node;
202
203	dev_node = udev_device_get_devnode(udev_dev);
204	if (!dev_node) {
205		return LIBUSB_ERROR_OTHER;
206	}
207
208	*sys_name = udev_device_get_sysname(udev_dev);
209	if (!*sys_name) {
210		return LIBUSB_ERROR_OTHER;
211	}
212
213	return linux_get_device_address(ctx, detached, busnum, devaddr,
214					dev_node, *sys_name);
215}
216
217static void udev_hotplug_event(struct udev_device* udev_dev)
218{
219	const char* udev_action;
220	const char* sys_name = NULL;
221	uint8_t busnum = 0, devaddr = 0;
222	int detached;
223	int r;
224
225	do {
226		udev_action = udev_device_get_action(udev_dev);
227		if (!udev_action) {
228			break;
229		}
230
231		detached = !strncmp(udev_action, "remove", 6);
232
233		r = udev_device_info(NULL, detached, udev_dev, &busnum, &devaddr, &sys_name);
234		if (LIBUSB_SUCCESS != r) {
235			break;
236		}
237
238		usbi_dbg("udev hotplug event. action: %s.", udev_action);
239
240		if (strncmp(udev_action, "add", 3) == 0) {
241			linux_hotplug_enumerate(busnum, devaddr, sys_name);
242		} else if (detached) {
243			linux_device_disconnected(busnum, devaddr, sys_name);
244		} else {
245			usbi_err(NULL, "ignoring udev action %s", udev_action);
246		}
247	} while (0);
248
249	udev_device_unref(udev_dev);
250}
251
252int linux_udev_scan_devices(struct libusb_context *ctx)
253{
254	struct udev_enumerate *enumerator;
255	struct udev_list_entry *devices, *entry;
256	struct udev_device *udev_dev;
257	const char *sys_name;
258	int r;
259
260	assert(udev_ctx != NULL);
261
262	enumerator = udev_enumerate_new(udev_ctx);
263	if (NULL == enumerator) {
264		usbi_err(ctx, "error creating udev enumerator");
265		return LIBUSB_ERROR_OTHER;
266	}
267
268	udev_enumerate_add_match_subsystem(enumerator, "usb");
269	udev_enumerate_scan_devices(enumerator);
270	devices = udev_enumerate_get_list_entry(enumerator);
271
272	udev_list_entry_foreach(entry, devices) {
273		const char *path = udev_list_entry_get_name(entry);
274		uint8_t busnum = 0, devaddr = 0;
275
276		udev_dev = udev_device_new_from_syspath(udev_ctx, path);
277
278		r = udev_device_info(ctx, 0, udev_dev, &busnum, &devaddr, &sys_name);
279		if (r) {
280			udev_device_unref(udev_dev);
281			continue;
282		}
283
284		linux_enumerate_device(ctx, busnum, devaddr, sys_name);
285		udev_device_unref(udev_dev);
286	}
287
288	udev_enumerate_unref(enumerator);
289
290	return LIBUSB_SUCCESS;
291}
292
293void linux_udev_hotplug_poll(void)
294{
295	struct udev_device* udev_dev;
296
297	usbi_mutex_static_lock(&linux_hotplug_lock);
298	do {
299		udev_dev = udev_monitor_receive_device(udev_monitor);
300		if (udev_dev) {
301			usbi_dbg("Handling hotplug event from hotplug_poll");
302			udev_hotplug_event(udev_dev);
303		}
304	} while (udev_dev);
305	usbi_mutex_static_unlock(&linux_hotplug_lock);
306}
307