/* -*- 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>

#include <libudev.h>

#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);

}