/* -*- 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);

}