1 files changed, 104 insertions, 0 deletions
diff --git a/src/detection/keyboard/keyboard_linux.c b/src/detection/keyboard/keyboard_linux.c
new file mode 100644
index 0000000..1a29abb
--- /dev/null
+++ b/src/detection/keyboard/keyboard_linux.c
@@ -0,0 +1,104 @@
+#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;
+}