libusb/os/linux_udev.c - third_party/libusb - Git at Google

 /* -*- Mode: C; c-basic-offset:8 ; indent-tabs-mode:t -*- */
 /*
  * Linux usbfs backend for libusb
  * Copyright (C) 2007-2009 Daniel Drake <dsd@gentoo.org>
  * Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com>
  * Copyright (c) 2012-2013 Nathan Hjelm <hjelmn@mac.com>
  *
  * 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 "libusbi.h"
 #include "linux_usbfs.h"

 #include <errno.h>
 #include <fcntl.h>
 #include <libudev.h>
 #include <poll.h>
 #include <pthread.h>
 #include <string.h>
 #include <unistd.h>

 /* udev context */
 static struct udev *udev_ctx = NULL;
 static int udev_monitor_fd = -1;
 static usbi_event_t udev_control_event = USBI_INVALID_EVENT;
 static struct udev_monitor *udev_monitor = NULL;
 static pthread_t linux_event_thread;

 static void udev_hotplug_event(struct udev_device *udev_dev);
 static void *linux_udev_event_thread_main(void *arg);

 int linux_udev_start_event_monitor(void)
 {
 	int r;

 	assert(udev_ctx == NULL);
 	udev_ctx = udev_new();
 	if (!udev_ctx) {
 		usbi_err(NULL, "could not create udev context");
 		goto err;
 	}

 	udev_monitor = udev_monitor_new_from_netlink(udev_ctx, "udev");
 	if (!udev_monitor) {
 		usbi_err(NULL, "could not initialize udev monitor");
 		goto err_free_ctx;
 	}

 	r = udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "usb", "usb_device");
 	if (r) {
 		usbi_err(NULL, "could not initialize udev monitor filter for \"usb\" subsystem");
 		goto err_free_monitor;
 	}

 	if (udev_monitor_enable_receiving(udev_monitor)) {
 		usbi_err(NULL, "failed to enable the udev monitor");
 		goto err_free_monitor;
 	}

 	udev_monitor_fd = udev_monitor_get_fd(udev_monitor);

 #if defined(FD_CLOEXEC)
 	/* Make sure the udev file descriptor is marked as CLOEXEC */
 	r = fcntl(udev_monitor_fd, F_GETFD);
 	if (r == -1) {
 		usbi_err(NULL, "failed to get udev monitor fd flags, errno=%d", errno);
 		goto err_free_monitor;
 	}
 	if (!(r & FD_CLOEXEC)) {
 		if (fcntl(udev_monitor_fd, F_SETFD, r | FD_CLOEXEC) == -1) {
 			usbi_err(NULL, "failed to set udev monitor fd flags, errno=%d", errno);
 			goto err_free_monitor;
 		}
 	}
 #endif

 	/* Some older versions of udev are not non-blocking by default,
 	 * so make sure this is set */
 	r = fcntl(udev_monitor_fd, F_GETFL);
 	if (r == -1) {
 		usbi_err(NULL, "failed to get udev monitor fd status flags, errno=%d", errno);
 		goto err_free_monitor;
 	}
 	if (!(r & O_NONBLOCK)) {
 		if (fcntl(udev_monitor_fd, F_SETFL, r | O_NONBLOCK) == -1) {
 			usbi_err(NULL, "failed to set udev monitor fd status flags, errno=%d", errno);
 			goto err_free_monitor;
 		}
 	}

 	r = usbi_create_event(&udev_control_event);
 	if (r) {
 		usbi_err(NULL, "failed to create udev control event");
 		goto err_free_monitor;
 	}

 	r = pthread_create(&linux_event_thread, NULL, linux_udev_event_thread_main, NULL);
 	if (r) {
 		usbi_err(NULL, "failed to create hotplug event thread (%d)", r);
 		goto err_destroy_event;
 	}

 	return LIBUSB_SUCCESS;

 err_destroy_event:
 	usbi_destroy_event(&udev_control_event);
 	udev_control_event = (usbi_event_t)USBI_INVALID_EVENT;
 err_free_monitor:
 	udev_monitor_unref(udev_monitor);
 	udev_monitor = NULL;
 	udev_monitor_fd = -1;
 err_free_ctx:
 	udev_unref(udev_ctx);
 err:
 	udev_ctx = NULL;
 	return LIBUSB_ERROR_OTHER;
 }

 int linux_udev_stop_event_monitor(void)
 {
 	int r;

 	assert(udev_ctx != NULL);
 	assert(udev_monitor != NULL);
 	assert(udev_monitor_fd != -1);

 	/* Signal the control event and wait for the thread to exit */
 	usbi_signal_event(&udev_control_event);

 	r = pthread_join(linux_event_thread, NULL);
 	if (r)
 		usbi_warn(NULL, "failed to join hotplug event thread (%d)", r);

 	usbi_destroy_event(&udev_control_event);
 	udev_control_event = (usbi_event_t)USBI_INVALID_EVENT;

 	/* Release the udev monitor */
 	udev_monitor_unref(udev_monitor);
 	udev_monitor = NULL;
 	udev_monitor_fd = -1;

 	/* Clean up the udev context */
 	udev_unref(udev_ctx);
 	udev_ctx = NULL;

 	return LIBUSB_SUCCESS;
 }

 static void *linux_udev_event_thread_main(void *arg)
 {
 	struct pollfd fds[] = {
 		{ .fd = USBI_EVENT_OS_HANDLE(&udev_control_event),
 		  .events = USBI_EVENT_POLL_EVENTS },
 		{ .fd = udev_monitor_fd,
 		  .events = POLLIN },
 	};
 	struct udev_device *udev_dev;
 	int r;

 	UNUSED(arg);

 #if defined(HAVE_PTHREAD_SETNAME_NP)
 	r = pthread_setname_np(pthread_self(), "libusb_event");
 	if (r)
 		usbi_warn(NULL, "failed to set hotplug event thread name, error=%d", r);
 #endif

 	usbi_dbg(NULL, "udev event thread entering");

 	while (1) {
 		r = poll(fds, 2, -1);
 		if (r == -1) {
 			/* check for temporary failure */
 			if (errno == EINTR)
 				continue;
 			usbi_err(NULL, "poll() failed, errno=%d", errno);
 			break;
 		}
 		if (fds[0].revents) {
 			/* activity on control event, exit */
 			break;
 		}
 		if (fds[1].revents) {
 			usbi_mutex_static_lock(&linux_hotplug_lock);
 			udev_dev = udev_monitor_receive_device(udev_monitor);
 			if (udev_dev)
 				udev_hotplug_event(udev_dev);
 			usbi_mutex_static_unlock(&linux_hotplug_lock);
 		}
 	}

 	usbi_dbg(NULL, "udev event thread exiting");

 	return NULL;
 }

 static int udev_device_info(struct libusb_context *ctx, int detached,
 			    struct udev_device *udev_dev, uint8_t *busnum,
 			    uint8_t *devaddr, const char **sys_name) {
 	const char *dev_node;

 	dev_node = udev_device_get_devnode(udev_dev);
 	if (!dev_node) {
 		return LIBUSB_ERROR_OTHER;
 	}

 	*sys_name = udev_device_get_sysname(udev_dev);
 	if (!*sys_name) {
 		return LIBUSB_ERROR_OTHER;
 	}

 	return linux_get_device_address(ctx, detached, busnum, devaddr,
 					dev_node, *sys_name, -1);
 }

 static void udev_hotplug_event(struct udev_device *udev_dev)
 {
 	const char *udev_action;
 	const char *sys_name = NULL;
 	uint8_t busnum = 0, devaddr = 0;
 	int detached;
 	int r;

 	do {
 		udev_action = udev_device_get_action(udev_dev);
 		if (!udev_action) {
 			break;
 		}

 		detached = !strncmp(udev_action, "remove", 6);

 		r = udev_device_info(NULL, detached, udev_dev, &busnum, &devaddr, &sys_name);
 		if (LIBUSB_SUCCESS != r) {
 			break;
 		}

 		usbi_dbg(NULL, "udev hotplug event. action: %s.", udev_action);

 		if (strncmp(udev_action, "add", 3) == 0) {
 			linux_hotplug_enumerate(busnum, devaddr, sys_name);
 		} else if (detached) {
 			linux_device_disconnected(busnum, devaddr);
 		} else if (strncmp(udev_action, "bind", 4) == 0) {
 			/* silently ignore "known unhandled" action */
 		} else {
 			usbi_err(NULL, "ignoring udev action %s", udev_action);
 		}
 	} while (0);

 	udev_device_unref(udev_dev);
 }

 int linux_udev_scan_devices(struct libusb_context *ctx)
 {
 	struct udev_enumerate *enumerator;
 	struct udev_list_entry *devices, *entry;
 	struct udev_device *udev_dev;
 	const char *sys_name;
 	int r;

 	assert(udev_ctx != NULL);

 	enumerator = udev_enumerate_new(udev_ctx);
 	if (NULL == enumerator) {
 		usbi_err(ctx, "error creating udev enumerator");
 		return LIBUSB_ERROR_OTHER;
 	}

 	udev_enumerate_add_match_subsystem(enumerator, "usb");
 	udev_enumerate_add_match_property(enumerator, "DEVTYPE", "usb_device");
 	udev_enumerate_scan_devices(enumerator);
 	devices = udev_enumerate_get_list_entry(enumerator);

 	entry = NULL;
 	udev_list_entry_foreach(entry, devices) {
 		const char *path = udev_list_entry_get_name(entry);
 		uint8_t busnum = 0, devaddr = 0;

 		udev_dev = udev_device_new_from_syspath(udev_ctx, path);

 		r = udev_device_info(ctx, 0, udev_dev, &busnum, &devaddr, &sys_name);
 		if (r) {
 			udev_device_unref(udev_dev);
 			continue;
 		}

 		linux_enumerate_device(ctx, busnum, devaddr, sys_name);
 		udev_device_unref(udev_dev);
 	}

 	udev_enumerate_unref(enumerator);

 	return LIBUSB_SUCCESS;
 }

 void linux_udev_hotplug_poll(void)
 {
 	struct udev_device *udev_dev;

 	usbi_mutex_static_lock(&linux_hotplug_lock);
 	do {
 		udev_dev = udev_monitor_receive_device(udev_monitor);
 		if (udev_dev) {
 			usbi_dbg(NULL, "Handling hotplug event from hotplug_poll");
 			udev_hotplug_event(udev_dev);
 		}
 	} while (udev_dev);
 	usbi_mutex_static_unlock(&linux_hotplug_lock);
 }
	/* -- Mode: C; c-basic-offset:8 ; indent-tabs-mode:t -- */
	/*
	* Linux usbfs backend for libusb
	* Copyright (C) 2007-2009 Daniel Drake <dsd@gentoo.org>
	* Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com>
	* Copyright (c) 2012-2013 Nathan Hjelm <hjelmn@mac.com>
	*
	* 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 "libusbi.h"
	#include "linux_usbfs.h"

	#include <errno.h>
	#include <fcntl.h>
	#include <libudev.h>
	#include <poll.h>
	#include <pthread.h>
	#include <string.h>
	#include <unistd.h>

	/* udev context */
	static struct udev *udev_ctx = NULL;
	static int udev_monitor_fd = -1;
	static usbi_event_t udev_control_event = USBI_INVALID_EVENT;
	static struct udev_monitor *udev_monitor = NULL;
	static pthread_t linux_event_thread;

	static void udev_hotplug_event(struct udev_device *udev_dev);
	static void linux_udev_event_thread_main(void arg);

	int linux_udev_start_event_monitor(void)
	{
	int r;

	assert(udev_ctx == NULL);
	udev_ctx = udev_new();
	if (!udev_ctx) {
	usbi_err(NULL, "could not create udev context");
	goto err;
	}

	udev_monitor = udev_monitor_new_from_netlink(udev_ctx, "udev");
	if (!udev_monitor) {
	usbi_err(NULL, "could not initialize udev monitor");
	goto err_free_ctx;
	}

	r = udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "usb", "usb_device");
	if (r) {
	usbi_err(NULL, "could not initialize udev monitor filter for \"usb\" subsystem");
	goto err_free_monitor;
	}

	if (udev_monitor_enable_receiving(udev_monitor)) {
	usbi_err(NULL, "failed to enable the udev monitor");
	goto err_free_monitor;
	}

	udev_monitor_fd = udev_monitor_get_fd(udev_monitor);

	#if defined(FD_CLOEXEC)
	/* Make sure the udev file descriptor is marked as CLOEXEC */
	r = fcntl(udev_monitor_fd, F_GETFD);
	if (r == -1) {
	usbi_err(NULL, "failed to get udev monitor fd flags, errno=%d", errno);
	goto err_free_monitor;
	}
	if (!(r & FD_CLOEXEC)) {
	if (fcntl(udev_monitor_fd, F_SETFD, r \| FD_CLOEXEC) == -1) {
	usbi_err(NULL, "failed to set udev monitor fd flags, errno=%d", errno);
	goto err_free_monitor;
	}
	}
	#endif

	/* Some older versions of udev are not non-blocking by default,
	* so make sure this is set */
	r = fcntl(udev_monitor_fd, F_GETFL);
	if (r == -1) {
	usbi_err(NULL, "failed to get udev monitor fd status flags, errno=%d", errno);
	goto err_free_monitor;
	}
	if (!(r & O_NONBLOCK)) {
	if (fcntl(udev_monitor_fd, F_SETFL, r \| O_NONBLOCK) == -1) {
	usbi_err(NULL, "failed to set udev monitor fd status flags, errno=%d", errno);
	goto err_free_monitor;
	}
	}

	r = usbi_create_event(&udev_control_event);
	if (r) {
	usbi_err(NULL, "failed to create udev control event");
	goto err_free_monitor;
	}

	r = pthread_create(&linux_event_thread, NULL, linux_udev_event_thread_main, NULL);
	if (r) {
	usbi_err(NULL, "failed to create hotplug event thread (%d)", r);
	goto err_destroy_event;
	}

	return LIBUSB_SUCCESS;

	err_destroy_event:
	usbi_destroy_event(&udev_control_event);
	udev_control_event = (usbi_event_t)USBI_INVALID_EVENT;
	err_free_monitor:
	udev_monitor_unref(udev_monitor);
	udev_monitor = NULL;
	udev_monitor_fd = -1;
	err_free_ctx:
	udev_unref(udev_ctx);
	err:
	udev_ctx = NULL;
	return LIBUSB_ERROR_OTHER;
	}

	int linux_udev_stop_event_monitor(void)
	{
	int r;

	assert(udev_ctx != NULL);
	assert(udev_monitor != NULL);
	assert(udev_monitor_fd != -1);

	/* Signal the control event and wait for the thread to exit */
	usbi_signal_event(&udev_control_event);

	r = pthread_join(linux_event_thread, NULL);
	if (r)
	usbi_warn(NULL, "failed to join hotplug event thread (%d)", r);

	usbi_destroy_event(&udev_control_event);
	udev_control_event = (usbi_event_t)USBI_INVALID_EVENT;

	/* Release the udev monitor */
	udev_monitor_unref(udev_monitor);
	udev_monitor = NULL;
	udev_monitor_fd = -1;

	/* Clean up the udev context */
	udev_unref(udev_ctx);
	udev_ctx = NULL;

	return LIBUSB_SUCCESS;
	}

	static void linux_udev_event_thread_main(void arg)
	{
	struct pollfd fds[] = {
	{ .fd = USBI_EVENT_OS_HANDLE(&udev_control_event),
	.events = USBI_EVENT_POLL_EVENTS },
	{ .fd = udev_monitor_fd,
	.events = POLLIN },
	};
	struct udev_device *udev_dev;
	int r;

	UNUSED(arg);

	#if defined(HAVE_PTHREAD_SETNAME_NP)
	r = pthread_setname_np(pthread_self(), "libusb_event");
	if (r)
	usbi_warn(NULL, "failed to set hotplug event thread name, error=%d", r);
	#endif

	usbi_dbg(NULL, "udev event thread entering");

	while (1) {
	r = poll(fds, 2, -1);
	if (r == -1) {
	/* check for temporary failure */
	if (errno == EINTR)
	continue;
	usbi_err(NULL, "poll() failed, errno=%d", errno);
	break;
	}
	if (fds[0].revents) {
	/* activity on control event, exit */
	break;
	}
	if (fds[1].revents) {
	usbi_mutex_static_lock(&linux_hotplug_lock);
	udev_dev = udev_monitor_receive_device(udev_monitor);
	if (udev_dev)
	udev_hotplug_event(udev_dev);
	usbi_mutex_static_unlock(&linux_hotplug_lock);
	}
	}

	usbi_dbg(NULL, "udev event thread exiting");

	return NULL;
	}

	static int udev_device_info(struct libusb_context *ctx, int detached,
	struct udev_device udev_dev, uint8_t busnum,
	uint8_t devaddr, const char *sys_name) {
	const char *dev_node;

	dev_node = udev_device_get_devnode(udev_dev);
	if (!dev_node) {
	return LIBUSB_ERROR_OTHER;
	}

	*sys_name = udev_device_get_sysname(udev_dev);
	if (!*sys_name) {
	return LIBUSB_ERROR_OTHER;
	}

	return linux_get_device_address(ctx, detached, busnum, devaddr,
	dev_node, *sys_name, -1);
	}

	static void udev_hotplug_event(struct udev_device *udev_dev)
	{
	const char *udev_action;
	const char *sys_name = NULL;
	uint8_t busnum = 0, devaddr = 0;
	int detached;
	int r;

	do {
	udev_action = udev_device_get_action(udev_dev);
	if (!udev_action) {
	break;
	}

	detached = !strncmp(udev_action, "remove", 6);

	r = udev_device_info(NULL, detached, udev_dev, &busnum, &devaddr, &sys_name);
	if (LIBUSB_SUCCESS != r) {
	break;
	}

	usbi_dbg(NULL, "udev hotplug event. action: %s.", udev_action);

	if (strncmp(udev_action, "add", 3) == 0) {
	linux_hotplug_enumerate(busnum, devaddr, sys_name);
	} else if (detached) {
	linux_device_disconnected(busnum, devaddr);
	} else if (strncmp(udev_action, "bind", 4) == 0) {
	/* silently ignore "known unhandled" action */
	} else {
	usbi_err(NULL, "ignoring udev action %s", udev_action);
	}
	} while (0);

	udev_device_unref(udev_dev);
	}

	int linux_udev_scan_devices(struct libusb_context *ctx)
	{
	struct udev_enumerate *enumerator;
	struct udev_list_entry devices, entry;
	struct udev_device *udev_dev;
	const char *sys_name;
	int r;

	assert(udev_ctx != NULL);

	enumerator = udev_enumerate_new(udev_ctx);
	if (NULL == enumerator) {
	usbi_err(ctx, "error creating udev enumerator");
	return LIBUSB_ERROR_OTHER;
	}

	udev_enumerate_add_match_subsystem(enumerator, "usb");
	udev_enumerate_add_match_property(enumerator, "DEVTYPE", "usb_device");
	udev_enumerate_scan_devices(enumerator);
	devices = udev_enumerate_get_list_entry(enumerator);

	entry = NULL;
	udev_list_entry_foreach(entry, devices) {
	const char *path = udev_list_entry_get_name(entry);
	uint8_t busnum = 0, devaddr = 0;

	udev_dev = udev_device_new_from_syspath(udev_ctx, path);

	r = udev_device_info(ctx, 0, udev_dev, &busnum, &devaddr, &sys_name);
	if (r) {
	udev_device_unref(udev_dev);
	continue;
	}

	linux_enumerate_device(ctx, busnum, devaddr, sys_name);
	udev_device_unref(udev_dev);
	}

	udev_enumerate_unref(enumerator);

	return LIBUSB_SUCCESS;
	}

	void linux_udev_hotplug_poll(void)
	{
	struct udev_device *udev_dev;

	usbi_mutex_static_lock(&linux_hotplug_lock);
	do {
	udev_dev = udev_monitor_receive_device(udev_monitor);
	if (udev_dev) {
	usbi_dbg(NULL, "Handling hotplug event from hotplug_poll");
	udev_hotplug_event(udev_dev);
	}
	} while (udev_dev);
	usbi_mutex_static_unlock(&linux_hotplug_lock);
	}