Strange input behavior after switching VTs

[shroff]

This seems to happen pretty consistently for me, that when I switch to a different VT and back, swaylock seems to start treating u as Esc (clearing input) and d as return (verifying password) - the reverse is not true. I can only unlock by logging into a different VT and running killall -9 swaylock.

Which flags I use don't seem to make a difference as calling swaylock -f from a terminal yields a the same result. I have to run with -f from a terminal since without it, swaylock crashes with wl_display@1: error 0: invalid object xx when I log in from a VT;

I have also attempted this on another machine and get the same result. swaylock -v reports 1.3, but pacman shows package version 1.4.2

[shroff]

Digging around with the code, it looks like the modifier key press state gets out of sync when you switch VTs, since the key release events don't get captured. A quick workaround is to press ctrl to reset state and it works fine after that.

Feel free to close or leave open to track.

[michalrus]

Feel free to close or leave open to track.

Let’s not close that, as that’s surely a bug!

---

Code to detect VT switches could be something like:

  int fd;
  if ((fd = open("/dev/console", O_NOCTTY)) < 0) {
    perror("open");
    _exit(-1);
  }

  for (;;) {
    struct vt_event ev;
    memset(&ev, 0, sizeof(ev));
    ev.event = VT_EVENT_SWITCH;
    if (ioctl(fd, VT_WAITEVENT, &ev) < 0) {
      perror("ioctl");
      _exit(-2);
    }
    handle_vt_switch(ev.oldev, ev.newev);
  }

oldev is the previous VT, and newev is the new one, as per https://github.com/torvalds/linux/blob/c0cc271173b2e1c2d8d0ceaef14e4dfa79eefc0d/include/uapi/linux/vt.h#L66-L78