xkeylog

commit 9514cb8f2bb57de34c8e5a63bda8da79e92aae64
parent f711b9eed4b7b9a9804bb8c284954b2a975545c3
Author: Louis Burda <quent.burda@gmail.com>
Date:   Mon, 20 Feb 2023 18:15:55 +0100

Using XInput2 extension for raw access

Diffstat:
M
Makefile
 | 
2
+-
M
xkeylog.c
 | 
160
+++++++++++++++++++++++++++++++++++++++++++++++++------------------------------

2 files changed, 100 insertions(+), 62 deletions(-)
diff --git a/Makefile b/Makefile
@@ -1,7 +1,7 @@
 PREFIX ?= /usr/local
 BINDIR ?= /bin
 
-LDLIBS = -lX11
+LDLIBS = -lX11 -lXi
 
 all: xkeylog
 
diff --git a/xkeylog.c b/xkeylog.c
@@ -1,7 +1,12 @@
+/* HEAVILY inspired by anko/xkbcat */
+
+#include <X11/extensions/XI2.h>
+#include <X11/extensions/XInput2.h>
+#include <X11/XKBlib.h>
 #include <X11/X.h>
 #include <X11/Xlib.h>
-#include <X11/Xutil.h>
 
+#include <X11/extensions/XKB.h>
 #include <sys/types.h>
 #include <signal.h>
 #include <err.h>
@@ -13,83 +18,116 @@
 
 const int mask = KeyPressMask | KeyReleaseMask | FocusChangeMask;
 
-FILE *logfile;
-Display *dpy;
-Window root;
-Window focus;
+int keysym_group;
+int xinput_op;
+int xkb_event;
 
 void
-close_log(void)
+check_support(Display *dpy, int *xinput_op)
 {
-	fclose(logfile);
+	int op, ev, err;
+	int vminor, vmajor;
+	int ret;
+
+	ret = XQueryExtension(dpy, "XInputExtension", xinput_op, &ev, &err);
+	if (!ret) errx(1, "missing XInput extension");
+
+	vmajor = 2;
+	vminor = 0;
+	ret = XIQueryVersion(dpy, &vmajor, &vminor);
+	if (ret == BadRequest)
+		errx(1, "missing XInput2 support");
+
+	ret = XkbQueryExtension(dpy, &op, &ev, &err, &vmajor, &vminor);
+	if (!ret) errx(1, "missing Xkb extension");
 }
 
 void
-handle_event(void)
+setup_xinput(Display *dpy, Window root)
 {
-	XComposeStatus comp;
-	XEvent ev;
-	KeySym ks;
-	char strbuf[128];
-	int revert;
-	int len;
-
-	XNextEvent(dpy, &ev);
-	switch (ev.type) {
-	case FocusOut:
-		fprintf(logfile, "Focus changed!\n");
-		fprintf(logfile, "Old focus is %d\n", (int)focus);
-		if (focus != root)
-			XSelectInput(dpy, focus, 0);
-		XGetInputFocus(dpy, &focus, &revert);
-		fprintf(logfile, "New focus is %d\n", (int)focus);
-		if (focus == PointerRoot)
-			focus = root;
-		XSelectInput(dpy, focus, mask);
-		break;
-	case KeyPress:
-		fprintf(logfile, "Got key!\n");
-		len = XLookupString(&ev.xkey, strbuf,
-			sizeof(strbuf) - 1, &ks, &comp);
-		if (len > 0) {
-			strbuf[len] = 0;
-			fprintf(logfile, "String is: %s\n", strbuf);
-		} else {
-			fprintf(logfile, "Key is: %d\n", (int)ks);
-		}
-		break;
-	}
+	XIEventMask mask;
+
+	mask.deviceid = XIAllMasterDevices;
+	mask.mask_len = XIMaskLen(XI_LASTEVENT);
+	mask.mask = calloc(mask.mask_len, 1);
+	if (!mask.mask) err(1, "calloc");
+
+	XISetMask(mask.mask, XI_RawKeyPress);
+	XISetMask(mask.mask, XI_RawKeyRelease);
+	XISelectEvents(dpy, root, &mask, 1);
+	XSync(dpy, false);
+
+	free(mask.mask);
 }
 
-int
-main(int argc, const char **argv)
+void
+handle_event(Display *dpy, Window root)
 {
-	const char *filepath;
-	const char **arg;
-	int revert;
-
-	filepath = NULL;
-	for (arg = argv + 1; *arg; arg++) {
-		if (!filepath) {
-			filepath = *arg;
-		} else {
-			errx(1, "unknown arg: %s", *arg);
-		}
+	XGenericEventCookie *cookie;
+	XkbEvent *xkbev;
+	XIRawEvent *xiev;
+	XEvent xev;
+	KeySym sym;
+	char *name;
+
+	cookie = &xev.xcookie;
+	XNextEvent(dpy, &xev);
+
+	if (!XGetEventData(dpy, cookie)) {
+		/* keysym group change event */
+		if (xev.type != xkb_event)
+			return;
+		xkbev = (XkbEvent *)&xev;
+		if (xkbev->any.xkb_type == XkbStateNotify)
+			keysym_group = xkbev->state.group;
+		return;
 	}
 
-	if (filepath) {
-		logfile = fopen(filepath, "w+");
-		if (!logfile) err(1, "fopen");
-		atexit(close_log);
+	if (cookie->type != GenericEvent || cookie->extension != xinput_op)
+		return;
+
+	if (cookie->evtype != XI_RawKeyPress && cookie->evtype != XI_RawKeyRelease)
+		return;
+
+	xiev = cookie->data;
+	sym = XkbKeycodeToKeysym(dpy, xiev->detail, keysym_group, 0);
+	if (sym == NoSymbol) {
+		if (keysym_group == 0) return;
+		/* NoSymbol on upper layers defers to base group */
+		sym = XkbKeycodeToKeysym(dpy, xiev->detail, 0, 0);
+		if (sym == NoSymbol) return;
+	}
+
+	name = XKeysymToString(sym);
+	if (name == NULL) return;
+
+	if (cookie->evtype == XI_RawKeyPress) {
+		printf("+%s\n", name);
 	} else {
-		logfile = stdout;
+		printf("-%s\n", name);
 	}
+	fflush(stdout);
+}
+
+int
+main(int argc, const char **argv)
+{
+	XkbStateRec state;
+	Display *dpy;
+	Window root;
 
 	dpy = XOpenDisplay(NULL);
 	root = DefaultRootWindow(dpy);
 
-	XGetInputFocus(dpy, &focus, &revert);
-	XSelectInput(dpy, focus, mask);
+	check_support(dpy, &xinput_op);
+	setup_xinput(dpy, root);
+
+	XkbSelectEventDetails(dpy, XkbUseCoreKbd, XkbStateNotify,
+		XkbGroupStateMask, XkbGroupStateMask);
+	XkbGetState(dpy, XkbUseCoreKbd, &state);
+	keysym_group = state.group;
 
-	while (1) handle_event();
+	while (1) {
+		handle_event(dpy, root);
+	}
 }