libusb1/os/linux_udev.c - 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 <config.h>

 #include <assert.h>
 #include <ctype.h>
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <poll.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/utsname.h>
 #include <sys/socket.h>
 #include <unistd.h>

 #ifdef GOOGLE_UNSUPPORTED_OS_HERCULES
 #include "third_party/appliance_linux/packages/eudev/usr/include/libudev.h"
 #else
 #include "third_party/systemd/src/libudev/libudev.h"
 #endif

 #include "libusbi.h"
 #include "linux_usbfs.h"

 /* udev context */
 static struct udev *udev_ctx = NULL;
 static int udev_monitor_fd = -1;
 static int udev_control_pipe[2] = {-1, -1};
 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, "geting udev monitor fd flags (%d)", errno);
 		goto err_free_monitor;
 	}
 	if (!(r & FD_CLOEXEC)) {
 		if (fcntl(udev_monitor_fd, F_SETFD, r | FD_CLOEXEC) == -1) {
 			usbi_err(NULL, "setting udev monitor fd flags (%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, "getting udev monitor fd status flags (%d)", errno);
 		goto err_free_monitor;
 	}
 	if (!(r & O_NONBLOCK)) {
 		if (fcntl(udev_monitor_fd, F_SETFL, r | O_NONBLOCK) == -1) {
 			usbi_err(NULL, "setting udev monitor fd status flags (%d)", errno);
 			goto err_free_monitor;
 		}
 	}

 	r = usbi_pipe(udev_control_pipe);
 	if (r) {
 		usbi_err(NULL, "could not create udev control pipe");
 		goto err_free_monitor;
 	}

 	r = pthread_create(&linux_event_thread, NULL, linux_udev_event_thread_main, NULL);
 	if (r) {
 		usbi_err(NULL, "creating hotplug event thread (%d)", r);
 		goto err_close_pipe;
 	}

 	return LIBUSB_SUCCESS;

 err_close_pipe:
 	close(udev_control_pipe[0]);
 	close(udev_control_pipe[1]);
 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)
 {
 	char dummy = 1;
 	int r;

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

 	/* Write some dummy data to the control pipe and
 	 * wait for the thread to exit */
 	r = write(udev_control_pipe[1], &dummy, sizeof(dummy));
 	if (r <= 0) {
 		usbi_warn(NULL, "udev control pipe signal failed");
 	}
 	pthread_join(linux_event_thread, NULL);

 	/* 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;

 	/* close and reset control pipe */
 	close(udev_control_pipe[0]);
 	close(udev_control_pipe[1]);
 	udev_control_pipe[0] = -1;
 	udev_control_pipe[1] = -1;

 	return LIBUSB_SUCCESS;
 }

 static void *linux_udev_event_thread_main(void *arg)
 {
 	char dummy;
 	int r;
 	ssize_t nb;
 	struct udev_device* udev_dev;
 	struct pollfd fds[] = {
 		{.fd = udev_control_pipe[0],
 		 .events = POLLIN},
 		{.fd = udev_monitor_fd,
 		 .events = POLLIN},
 	};

 	usbi_dbg("udev event thread entering.");

 	while ((r = poll(fds, 2, -1)) >= 0 || errno == EINTR) {
 		if (r < 0) {
 			/* temporary failure */
 			continue;
 		}
 		if (fds[0].revents & POLLIN) {
 			/* activity on control pipe, read the byte and exit */
 			nb = read(udev_control_pipe[0], &dummy, sizeof(dummy));
 			if (nb <= 0) {
 				usbi_warn(NULL, "udev control pipe read failed");
 			}
 			break;
 		}
 		if (fds[1].revents & POLLIN) {
 			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("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("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 {
 			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("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 <config.h>

	#include <assert.h>
	#include <ctype.h>
	#include <dirent.h>
	#include <errno.h>
	#include <fcntl.h>
	#include <poll.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/ioctl.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <sys/utsname.h>
	#include <sys/socket.h>
	#include <unistd.h>

	#ifdef GOOGLE_UNSUPPORTED_OS_HERCULES
	#include "third_party/appliance_linux/packages/eudev/usr/include/libudev.h"
	#else
	#include "third_party/systemd/src/libudev/libudev.h"
	#endif

	#include "libusbi.h"
	#include "linux_usbfs.h"

	/* udev context */
	static struct udev *udev_ctx = NULL;
	static int udev_monitor_fd = -1;
	static int udev_control_pipe[2] = {-1, -1};
	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, "geting udev monitor fd flags (%d)", errno);
	goto err_free_monitor;
	}
	if (!(r & FD_CLOEXEC)) {
	if (fcntl(udev_monitor_fd, F_SETFD, r \| FD_CLOEXEC) == -1) {
	usbi_err(NULL, "setting udev monitor fd flags (%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, "getting udev monitor fd status flags (%d)", errno);
	goto err_free_monitor;
	}
	if (!(r & O_NONBLOCK)) {
	if (fcntl(udev_monitor_fd, F_SETFL, r \| O_NONBLOCK) == -1) {
	usbi_err(NULL, "setting udev monitor fd status flags (%d)", errno);
	goto err_free_monitor;
	}
	}

	r = usbi_pipe(udev_control_pipe);
	if (r) {
	usbi_err(NULL, "could not create udev control pipe");
	goto err_free_monitor;
	}

	r = pthread_create(&linux_event_thread, NULL, linux_udev_event_thread_main, NULL);
	if (r) {
	usbi_err(NULL, "creating hotplug event thread (%d)", r);
	goto err_close_pipe;
	}

	return LIBUSB_SUCCESS;

	err_close_pipe:
	close(udev_control_pipe[0]);
	close(udev_control_pipe[1]);
	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)
	{
	char dummy = 1;
	int r;

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

	/* Write some dummy data to the control pipe and
	* wait for the thread to exit */
	r = write(udev_control_pipe[1], &dummy, sizeof(dummy));
	if (r <= 0) {
	usbi_warn(NULL, "udev control pipe signal failed");
	}
	pthread_join(linux_event_thread, NULL);

	/* 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;

	/* close and reset control pipe */
	close(udev_control_pipe[0]);
	close(udev_control_pipe[1]);
	udev_control_pipe[0] = -1;
	udev_control_pipe[1] = -1;

	return LIBUSB_SUCCESS;
	}

	static void linux_udev_event_thread_main(void arg)
	{
	char dummy;
	int r;
	ssize_t nb;
	struct udev_device* udev_dev;
	struct pollfd fds[] = {
	{.fd = udev_control_pipe[0],
	.events = POLLIN},
	{.fd = udev_monitor_fd,
	.events = POLLIN},
	};

	usbi_dbg("udev event thread entering.");

	while ((r = poll(fds, 2, -1)) >= 0 \|\| errno == EINTR) {
	if (r < 0) {
	/* temporary failure */
	continue;
	}
	if (fds[0].revents & POLLIN) {
	/* activity on control pipe, read the byte and exit */
	nb = read(udev_control_pipe[0], &dummy, sizeof(dummy));
	if (nb <= 0) {
	usbi_warn(NULL, "udev control pipe read failed");
	}
	break;
	}
	if (fds[1].revents & POLLIN) {
	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("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("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 {
	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("Handling hotplug event from hotplug_poll");
	udev_hotplug_event(udev_dev);
	}
	} while (udev_dev);
	usbi_mutex_static_unlock(&linux_hotplug_lock);
	}