[hackers] [PATCH v2 04/14] Fix SIGTERM handler - flip terminate flag in sigterm handler & cleanup properly

[Maarten van Gompel]

From: Miles Alan <m...@milesalan.com>

Modify run function to use select() with a timeout since X events will be
blocked otherwise and terminate wouldn't apply for a while.
---
 svkbd.c | 47 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 32 insertions(+), 15 deletions(-)

diff --git a/svkbd.c b/svkbd.c
index 7dfb27f..27e2af2 100644
--- a/svkbd.c
+++ b/svkbd.c
@@ -14,6 +14,8 @@
 #include <X11/Xproto.h>
 #include <X11/extensions/XTest.h>
 #include <signal.h>
+#include <sys/select.h>
+

 /* macros */
 #define MAX(a, b)       ((a) > (b) ? (a) : (b))
@@ -97,10 +99,10 @@ static Bool running = True, isdock = False;
 static KeySym pressedmod = 0;
 static int rows = 0, ww = 0, wh = 0, wx = 0, wy = 0;
 static char *name = "svkbd";
-static int terminate = 0;

 Bool ispressing = False;
 Bool baselayer = True;
+Bool sigtermd = False;

 /* configuration, allows nested code to access above variables */
 #include "config.h"
@@ -188,6 +190,21 @@ buttonrelease(XEvent *e) {

 void
 cleanup(void) {
+       int i;
+
+       // E.g. Generally in scripts we call SIGTERM on svkbd in which case
+       //      if the user is holding for example the enter key (to execute
+       //      the kill or script that does the kill), that causes an issue
+       //      since then X doesn't know the keyup is never coming.. (since
+       //      process will be dead before finger lifts - in that case we
+       //      just trigger out fake up presses for all keys
+       if (sigtermd) {
+               for (i = 0; i < LENGTH(keys); i++) {
+                       XTestFakeKeyEvent(dpy, XKeysymToKeycode(dpy, 
keys[i].keysym), False, 0);
+               }
+       }
+       XSync(dpy, False);
+
        if(dc.font.set)
                XFreeFontSet(dpy, dc.font.set);
        else
@@ -438,13 +455,21 @@ unpress(Key *k, KeySym mod) {
 void
 run(void) {
        XEvent ev;
-
-       /* main event loop */
-       XSync(dpy, False);
-       while(running) {
+       int xfd;
+       fd_set fds;
+       struct timeval tv;
+
+       xfd = ConnectionNumber(dpy);
+       FD_ZERO(&fds);
+       FD_SET(xfd, &fds);
+       tv.tv_usec = 0;
+       tv.tv_sec = 1;
+       while (running) {
+               select(xfd + 1, &fds, NULL, NULL, &tv);
                XNextEvent(dpy, &ev);
-               if(handler[ev.type])
+               if(handler[ev.type]) {
                        (handler[ev.type])(&ev); /* call handler */
+               }
        }
 }

@@ -597,16 +622,8 @@ togglelayer() {
 void
 sigterm(int sig)
 {
-       // E.g. Since sometimes we might use svkbd, to kill svkbd - e.g. in
-       // terminal or script (pkill svkbd), .. that signal might register 
before
-       // the keyup event is processed so X thinks the key is held down 
forever..
-       // so here we keyup every key & exit (XK_Break) to keyup cleanup 
properly
-       int i;
-       for(i = 0; i < LENGTH(keys); i++) {
-         XTestFakeKeyEvent(dpy, XKeysymToKeycode(dpy, keys[i].keysym), False, 
0);
-       }
        running = False;
-       //XTestFakeKeyEvent(dpy, XK_Break, False, 0);
+       sigtermd = True;
 }

 int
--
2.27.0