Initial commit

.gitignore

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+*~
+\#*\#
+.\#*
+build
+result
+result-*
+

Makefile

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+.PHONY: all clean
+
+CFLAGS += -DREMARKABLE_VERSION=$(REMARKABLE_VERSION)
+
+all: build/librM-input-devices.so build/librM-input-devices-standalone.a build/rM-mk-uinput build/rM-mk-uinput-standalone
+clean:
+	rm -rf build
+
+build:
+	mkdir -p build
+build/%.o: %.c | build
+	$(CC) $(CFLAGS) -c $< -o $@ $(LDFLAGS)
+build/%.a: | build
+	$(AR) cr $@ $^
+build/%.so: | build
+	$(CC) -shared -z defs -o $@ $^ $(LDFLAGS)
+
+build/uinput.bin: | build
+	$(OBJCOPY) -I binary -O elf32-littlearm -B arm $(UINPUT_KO) $@
+
+build/rM-input-devices.o: rM-input-devices.h
+build/rM-input-devices-standalone.o: build/rM-input-devices.o input-devices-standalone.ld build/uinput.bin
+	$(LD) -Tinput-devices-standalone.ld -i -o $@ build/rM-input-devices.o
+
+build/rM-mk-uinput.o: rM-input-devices.h
+
+build/librM-input-devices-standalone.a: build/rM-input-devices-standalone.o
+
+build/librM-input-devices.so: build/rM-input-devices.o
+build/librM-input-devices.so: private override LDFLAGS += -ludev -lpthread
+
+build/rM-mk-uinput: build/rM-mk-uinput.o build/librM-input-devices.so | build
+	$(CC) $(CFLAGS) -o $@ $< -Lbuild -lrM-input-devices
+build/rM-mk-uinput-standalone: build/rM-mk-uinput.o build/librM-input-devices-standalone.a
+	$(CC) $(CFLAGS) -o $@ $< -Lbuild -lrM-input-devices-standalone -ludev -lpthread

README.md

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+# Introduction
+
+This library provides a simple API for receiving and sending
+digitizer/touch/keyboard events on the [reMarkable
+tablets](https://remarkable.com). Currently, the main consumer is
+[rM-vnc-server](https://github.com/pl-semiotics/rM-vnc-server). It
+also supports using uinput to emulate the presence of such devices,
+which may be useful in virtualized environments.
+
+# Building
+
+The supported way to build this is via the
+[Nix](https://nixos.org/nix) package manager, through the
+[nix-remarkable](https://github.com/pl-semiotics/nix-remarkable)
+expressions. To build just this project via `nix build` from this
+repo, download it into the `pkgs/` directory of `nix-remarkable`.
+
+For any other system, the [Makefile](./Makefile) should provide some
+guidance; please set `REMARKABLE_VERSION` to one or two (depending on
+which version you are building for), and, if interested in the
+standalone (statically linked, with a bundled uinput kernel module)
+version of the library, provide the path to appropriate kernel module
+in the `UINPUT_KO` environment variable.
+
+Prebuilt binaries are available in the [Releases
+tab](https://github.com/pl-semiotics/rM-input-devices/releases).
+
+# Usage
+
+For the library, see [rM-input-devices.h](./rM-input-devices.h) for
+the interface. A simple executable `rM-mk-uinput` (which takes no
+arguments and does nothing but create uinput devices for any missing
+input devices) is also provided.

default.nix

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+(import ../.. {}).rmPkgs.rM-input-devices

derivation.nix

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+{ stdenv, lib, linuxHeaders, linuxPackages, targetPlatform }:
+
+stdenv.mkDerivation {
+  pname = "rM-input-devices";
+  version = "0.0.1";
+  src = lib.cleanSource ./.;
+  buildInputs = [ linuxHeaders ];
+  REMARKABLE_VERSION = targetPlatform.platform.rmVersion;
+  UINPUT_KO = "${linuxPackages.kernel}/lib/modules/${linuxPackages.kernel.modDirVersion}/kernel/drivers/input/misc/uinput.ko";
+  outputs = [ "out" "dev" ];
+  installPhase = ''
+    mkdir -p $out/bin
+    cp build/rM-mk-uinput{,-standalone} $out/bin
+    mkdir -p $dev/include $dev/lib
+    cp rM-input-devices.h $dev/include
+    cp build/librM-input-devices{.so,-standalone.a} $dev/lib
+  '';
+}

input-devices-standalone.ld

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+SECTIONS
+{
+  .uinput_ko : {
+    uinput_ko_begin = . ;
+    build/uinput.bin(.data)
+    uinput_ko_end = . ;
+  }
+}

private.h

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+#include "rM-input-devices.h"
+
+#include <pthread.h>
+
+
+struct fd_list {
+  int fd;
+  struct fd_list *next;
+};
+
+#define N_SLOTS 32
+struct wacom_data {
+  pthread_mutex_t mutex;
+  int pen_down; int touch_down;
+  int abs_x; int abs_y; int abs_pressure;
+  int drop_until_syn;
+  void *userdata;
+  uint coord_kind;
+};
+struct touch_data {
+  pthread_mutex_t mutex;
+  int slots[N_SLOTS]; /* keep track of the tracking id for each slot */
+  int abs_x[N_SLOTS];
+  int abs_y[N_SLOTS];
+  int current_slot;
+  /* the kernel currently uses (mt->trkid++ & TRKID_MAX) to get a new
+   * tracking id, so we just stay a few thousand ids ahead of the
+   * kernel */
+#define TRKID_MAX 0xffff
+#define KERN_TRKID_OFFSET 4096
+  uint next_trkid;
+  int drop_until_syn;
+  void *userdata;
+  uint coord_kind;
+};
+struct key_data {
+  pthread_mutex_t mutex;
+  void *userdata;
+};
+
+struct rM_input_devices_priv {
+  struct fd_list* extra_wacom_fds;
+  struct fd_list* extra_touch_fds;
+  struct fd_list* extra_key_fds;
+  handle_wacom_event_t hwe;
+  handle_touch_event_t hte;
+  handle_key_event_t hke;
+  pthread_mutex_t input_thread_mutex;
+  int input_thread_running;
+  pthread_t input_thread;
+  struct wacom_data wd;
+  struct touch_data td;
+  struct key_data kd;
+};