initial import of hidapi netbsd uhid native backend from mainstream

libusb/hidapi@c19ae12
libusb/hidapi#612

src/hidapi/CMakeLists.txt

@@ -42,6 +42,9 @@ elseif(NOT WIN32)
         option(HIDAPI_WITH_HIDRAW "Build HIDRAW-based implementation of HIDAPI" ON)
         option(HIDAPI_WITH_LIBUSB "Build LIBUSB-based implementation of HIDAPI" ON)
     endif()
+    if(CMAKE_SYSTEM_NAME MATCHES "NetBSD")
+        option(HIDAPI_WITH_NETBSD "Build NetBSD/UHID implementation of HIDAPI" ON)
+    endif()
 endif()
 
 option(BUILD_SHARED_LIBS "Build shared version of the libraries, otherwise build statically" ON)

src/hidapi/SDL_hidapi.c

@@ -573,6 +573,8 @@ typedef struct PLATFORM_hid_device_ PLATFORM_hid_device;
 
 #ifdef __LINUX__
 #include "SDL_hidapi_linux.h"
+#elif defined(__NETBSD__)
+#include "SDL_hidapi_netbsd.h"
 #elif defined(__MACOS__)
 #include "SDL_hidapi_mac.h"
 #elif defined(__WINDOWS__) || defined(__WINGDK__)

src/hidapi/SDL_hidapi_netbsd.h

@@ -0,0 +1,25 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#undef HIDAPI_H__
+#include "netbsd/hid.c"
+#define HAVE_PLATFORM_BACKEND 1
+#define udev_ctx              1

src/hidapi/netbsd/CMakeLists.txt

@@ -0,0 +1,35 @@
+cmake_minimum_required(VERSION 3.6.3 FATAL_ERROR)
+
+add_library(hidapi_netbsd
+    ${HIDAPI_PUBLIC_HEADERS}
+    hid.c
+)
+target_link_libraries(hidapi_netbsd PUBLIC hidapi_include)
+
+find_package(Threads REQUIRED)
+
+target_link_libraries(hidapi_netbsd PRIVATE Threads::Threads)
+
+set_target_properties(hidapi_netbsd
+    PROPERTIES
+        EXPORT_NAME "netbsd"
+        OUTPUT_NAME "hidapi-netbsd"
+        VERSION ${PROJECT_VERSION}
+        SOVERSION ${PROJECT_VERSION_MAJOR}
+        PUBLIC_HEADER "${HIDAPI_PUBLIC_HEADERS}"
+)
+
+# compatibility with find_package()
+add_library(hidapi::netbsd ALIAS hidapi_netbsd)
+# compatibility with raw library link
+add_library(hidapi-netbsd ALIAS hidapi_netbsd)
+
+if(HIDAPI_INSTALL_TARGETS)
+    install(TARGETS hidapi_netbsd EXPORT hidapi
+        LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+        ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+        PUBLIC_HEADER DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/hidapi"
+    )
+endif()
+
+hidapi_configure_pc("${PROJECT_ROOT}/pc/hidapi-netbsd.pc.in")

src/hidapi/netbsd/README.md

@@ -0,0 +1,29 @@
+Implementation Notes
+--------------------
+NetBSD maps every `uhidev` device to one or more `uhid`
+devices. Each `uhid` device only supports one report ID.
+The parent device `uhidev` creates one `uhid` device per
+report ID found in the hardware's report descriptor.
+
+In the event there are no report ID(s) found within the
+report descriptor, only one `uhid` device with a report ID
+of `0` is created.
+
+In order to remain compatible with existing `hidapi` APIs,
+all the `uhid` devices created by the parent `uhidev` device
+must be opened under the same `hid_device` instance to ensure
+that we can route reports to their appropriate `uhid` device.
+
+Internally the `uhid` driver will insert the report ID as
+needed so we must also omit the report ID in any situation
+where the `hidapi` API expects it to be included in the
+report data stream.
+
+Given the design of `uhid`, it must be augmented with extra
+platform specific APIs to ensure that the exact relationship
+between `uhidev` devices and `uhid` devices can be determined.
+
+The NetBSD implementation does this via the `drvctl` kernel
+driver. At present there is no known way to do this on OpenBSD
+for a `uhid` implementation to be at the same level as the
+NetBSD one.