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#include "keyboard.h"
#include "common/io.h"
#include "common/strutil.h"
#include <linux/input-event-codes.h>
const char* ffDetectKeyboard(FFlist* devices /* List of FFKeyboardDevice */) {
// Parse /proc/bus/input/devices to find keyboards with a "kbd" handler.
// This detects both wired and Bluetooth keyboards uniformly.
FF_STRBUF_AUTO_DESTROY content = ffStrbufCreate();
if (!ffAppendFileBuffer("/proc/bus/input/devices", &content)) {
return "ffAppendFileBuffer(\"/proc/bus/input/devices\") == NULL";
}
FFstrbuf kbd = ffStrbufCreateStatic("kbd");
FFKeyboardDevice device = {
.name = ffStrbufCreate(),
.serial = ffStrbufCreate()
};
char* line = NULL;
size_t len = 0;
while (ffStrbufGetline(&line, &len, &content)) {
switch (line[0]) {
case 'N': {
const uint32_t prefixLen = strlen("N: Name=");
if (__builtin_expect(len <= prefixLen, false)) {
continue;
}
const char* name = line + prefixLen;
const uint32_t nameLen = (uint32_t) len - prefixLen;
ffStrbufSetNS(&device.name, nameLen, name);
ffStrbufTrim(&device.name, '"');
continue;
}
case 'H': {
const uint32_t prefixLen = strlen("H: Handlers=");
if (__builtin_expect(len <= prefixLen, false)) {
continue;
}
const char* handlers = line + prefixLen;
const uint32_t handlersLen = (uint32_t) len - prefixLen;
if (!ffStrbufMatchSeparatedNS(&kbd, handlersLen, handlers, ' ')) {
goto skipDevice;
}
continue;
}
case 'B': {
const char* bits = line + strlen("B: ");
if (ffStrStartsWith(bits, "EV=")) {
// Check EV_REP (auto-repeat, bit 20) to filter pseudo-keyboards (Power Button, PC Speaker).
const char* evBits = bits + strlen("EV=");
uint64_t val = strtoull(evBits, NULL, 16);
if (!(val & (1ULL << EV_REP))) {
goto skipDevice;
}
} else if (ffStrStartsWith(bits, "KEY=")) {
// Check KEY_A (bit 30) to filter media remotes and headset controls.
// The key capability bitmap is space-separated hex longs, MSB first;
// KEY_A falls in the last (least significant) word on all architectures.
const char* keyBits = bits + strlen("KEY=");
const char* lastWord = memrchr(keyBits, ' ', len - (size_t) (keyBits - line));
lastWord = lastWord ? lastWord + 1 : keyBits;
uint64_t val = strtoull(lastWord, NULL, 16);
if (!(val & (1ULL << KEY_A))) {
goto skipDevice;
}
}
continue;
}
case 'U': {
const uint32_t prefixLen = strlen("U: Uniq=");
if (__builtin_expect(len <= prefixLen, false)) {
continue;
}
const char* uniq = line + prefixLen;
const uint32_t uniqLen = (uint32_t) len - prefixLen;
ffStrbufSetNS(&device.serial, uniqLen, uniq);
continue;
}
case '\0':
// End of device entry; add to list if it has a name.
if (device.name.length > 0) {
FFKeyboardDevice* added = FF_LIST_ADD(FFKeyboardDevice, *devices);
ffStrbufInitMove(&added->name, &device.name);
ffStrbufInitMove(&added->serial, &device.serial);
}
continue;
default:
continue;
}
skipDevice:
// Skip to the end of the current device entry.
while (line[0] != '\0' && ffStrbufGetline(&line, &len, &content));
// Despite the fn name, it resets the string buffer to initial state
ffStrbufDestroy(&device.name);
ffStrbufDestroy(&device.serial);
}
return NULL;
}
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