Add udev helper library to v4l2 plugin.
This adds a small helper library to the v4l2 plugin that uses udev to get events for v4l2 devices.master
fryshorts
parent
43184d1775
commit
1bae57668c
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@ -6,6 +6,8 @@ if(DISABLE_V4L2)
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endif()
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find_package(Libv4l2)
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find_package(LibUDev QUIET)
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if(NOT LIBV4L2_FOUND AND ENABLE_V4L2)
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message(FATAL_ERROR "libv4l2 not found bit plugin set as enabled")
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elseif(NOT LIBV4L2_FOUND)
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@ -13,10 +15,20 @@ elseif(NOT LIBV4L2_FOUND)
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return()
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endif()
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if(NOT UDEV_FOUND OR DISABLE_UDEV)
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message(STATUS "udev disabled for v4l2 plugin")
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else()
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set(linux-v4l2-udev_SOURCES
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v4l2-udev.c
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)
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add_definitions(-DHAVE_UDEV)
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endif()
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set(linux-v4l2_SOURCES
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linux-v4l2.c
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v4l2-input.c
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v4l2-helpers.c
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${linux-v4l2-udev_SOURCES}
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)
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add_library(linux-v4l2 MODULE
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@ -25,6 +37,7 @@ add_library(linux-v4l2 MODULE
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target_link_libraries(linux-v4l2
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libobs
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${LIBV4L2_LIBRARIES}
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${UDEV_LIBRARIES}
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)
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install_obs_plugin_with_data(linux-v4l2 data)
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@ -0,0 +1,224 @@
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/*
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Copyright (C) 2014 by Leonhard Oelke <leonhard@in-verted.de>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libudev.h>
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#include <util/threading.h>
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#include <util/darray.h>
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#include <obs.h>
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#include "v4l2-udev.h"
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#define UDEV_DATA(voidptr) struct v4l2_udev_mon_t *m \
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= (struct v4l2_udev_mon_t *) voidptr;
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/** udev action enum */
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enum udev_action {
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UDEV_ACTION_ADDED,
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UDEV_ACTION_REMOVED,
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UDEV_ACTION_UNKNOWN
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};
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/** monitor object holding the callbacks */
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struct v4l2_udev_mon_t {
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/* data for the device added callback */
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void *dev_added_userdata;
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v4l2_device_added_cb dev_added_cb;
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/* data for the device removed callback */
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void *dev_removed_userdata;
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v4l2_device_removed_cb dev_removed_cb;
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};
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/* global data */
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static uint_fast32_t udev_refs = 0;
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static pthread_mutex_t udev_mutex = PTHREAD_MUTEX_INITIALIZER;
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static pthread_t udev_thread;
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static os_event_t *udev_event;
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static DARRAY(struct v4l2_udev_mon_t) udev_clients;
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/**
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* udev gives us the device action as string, so we convert it here ...
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*
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* @param action the udev action as string
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* @return the udev action as enum value
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*/
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static enum udev_action udev_action_to_enum(const char *action)
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{
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if (!action)
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return UDEV_ACTION_UNKNOWN;
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if (!strncmp("add", action, 3))
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return UDEV_ACTION_ADDED;
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if (!strncmp("remove", action, 6))
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return UDEV_ACTION_REMOVED;
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return UDEV_ACTION_UNKNOWN;
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}
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/**
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* Call all registered callbacks with the event
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*
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* @param dev udev device that had an event occuring
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*/
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static inline void udev_call_callbacks(struct udev_device *dev)
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{
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const char *node;
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enum udev_action action;
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pthread_mutex_lock(&udev_mutex);
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node = udev_device_get_devnode(dev);
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action = udev_action_to_enum(udev_device_get_action(dev));
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for (size_t idx = 0; idx < udev_clients.num; idx++) {
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struct v4l2_udev_mon_t *c = &udev_clients.array[idx];
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switch (action) {
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case UDEV_ACTION_ADDED:
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if (!c->dev_added_cb)
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continue;
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c->dev_added_cb(node, c->dev_added_userdata);
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break;
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case UDEV_ACTION_REMOVED:
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if (!c->dev_removed_cb)
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continue;
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c->dev_removed_cb(node, c->dev_removed_userdata);
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break;
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default:
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break;
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}
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}
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pthread_mutex_unlock(&udev_mutex);
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}
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/**
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* Event listener thread
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*/
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static void *udev_event_thread(void *vptr)
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{
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UNUSED_PARAMETER(vptr);
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int fd;
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fd_set fds;
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struct timeval tv;
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struct udev *udev;
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struct udev_monitor *mon;
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struct udev_device *dev;
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/* set up udev monitoring */
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udev = udev_new();
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mon = udev_monitor_new_from_netlink(udev, "udev");
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udev_monitor_filter_add_match_subsystem_devtype(
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mon, "video4linux", NULL);
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if (udev_monitor_enable_receiving(mon) < 0)
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return NULL;
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/* set up fds */
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fd = udev_monitor_get_fd(mon);
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while (os_event_try(udev_event) == EAGAIN) {
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FD_ZERO(&fds);
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FD_SET(fd, &fds);
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tv.tv_sec = 1;
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tv.tv_usec = 0;
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if (select(fd + 1, &fds, NULL, NULL, &tv) <= 0)
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continue;
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dev = udev_monitor_receive_device(mon);
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if (!dev)
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continue;
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udev_call_callbacks(dev);
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udev_device_unref(dev);
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}
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udev_monitor_unref(mon);
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udev_unref(udev);
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return NULL;
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}
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void *v4l2_init_udev(void)
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{
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struct v4l2_udev_mon_t *ret = NULL;
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pthread_mutex_lock(&udev_mutex);
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/* set up udev */
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if (udev_refs == 0) {
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if (os_event_init(&udev_event, OS_EVENT_TYPE_MANUAL) != 0)
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goto fail;
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if (pthread_create(&udev_thread, NULL, udev_event_thread,
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NULL) != 0)
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goto fail;
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da_init(udev_clients);
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}
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udev_refs++;
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/* create monitor object */
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ret = da_push_back_new(udev_clients);
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fail:
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pthread_mutex_unlock(&udev_mutex);
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return ret;
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}
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void v4l2_unref_udev(void *monitor)
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{
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UDEV_DATA(monitor);
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pthread_mutex_lock(&udev_mutex);
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/* clean up monitor object */
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da_erase_item(udev_clients, m);
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/* unref udev monitor */
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udev_refs--;
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if (udev_refs == 0) {
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os_event_signal(udev_event);
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pthread_join(udev_thread, NULL);
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os_event_destroy(udev_event);
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da_free(udev_clients);
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}
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pthread_mutex_unlock(&udev_mutex);
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}
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void v4l2_set_device_added_callback(void *monitor, v4l2_device_added_cb cb,
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void *userdata)
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{
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UDEV_DATA(monitor);
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if (!m)
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return;
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m->dev_added_cb = cb;
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m->dev_added_userdata = userdata;
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}
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void v4l2_set_device_removed_callback(void *monitor, v4l2_device_removed_cb cb,
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void *userdata)
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{
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UDEV_DATA(monitor);
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if (!m)
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return;
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m->dev_removed_cb = cb;
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m->dev_removed_userdata = userdata;
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}
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@ -0,0 +1,80 @@
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/*
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Copyright (C) 2014 by Leonhard Oelke <leonhard@in-verted.de>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <inttypes.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* Initialize udev system to watch for device events
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*
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* @return monitor object, or NULL on error
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*/
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void *v4l2_init_udev(void);
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/**
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* Unref the udev system
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*
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* This will also remove any registered callbacks if there are any
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*
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* @param monitor monitor object
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*/
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void v4l2_unref_udev(void *monitor);
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/**
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* Callback when a device was added.
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*
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* @param dev device node of the device that was added
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* @param userdata pointer to userdata specified when registered
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*/
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typedef void (*v4l2_device_added_cb)(const char *dev, void *userdata);
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/**
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* Callback when a device was removed.
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*
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* @param dev device node of the device that was removed
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* @param userdata pointer to userdata specified when registered
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*/
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typedef void (*v4l2_device_removed_cb)(const char *dev, void *userdata);
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/**
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* Register the device added callback
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*
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* @param monitor monitor object
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* @param cb the function that should be called
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* @param userdata pointer to userdata that should be passed to the callback
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*/
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void v4l2_set_device_added_callback(void *monitor, v4l2_device_added_cb cb,
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void *userdata);
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/**
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* Register the device remove callback
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*
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* @param monitor monitor object
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* @param cb the function that should be called
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* @param userdata pointer to userdata that should be passed to the callback
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*/
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void v4l2_set_device_removed_callback(void *monitor, v4l2_device_removed_cb cb,
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void *userdata);
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#ifdef __cplusplus
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}
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#endif
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