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terminal: Fix VT numbering on FreeBSD

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FreeBSD adds one to the VT number returned by the GET_ACTIVE ioctl, so
to match things up, the wrapper here subtracted by one. This lead to
ttyv0 being named VT 0. This had the side-effect of VT numbering not
matching expectations, and switching not behaving as intended.

Align numbers with expectations, and move the required subtraction to
terminal_open, so that VT 1 matches ttyv0.
This commit is contained in:
Kenny Levinsen 2020-09-22 00:54:51 +02:00
parent 0132841987
commit 521d95349f
1 changed files with 34 additions and 26 deletions
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60
common/terminal.c
View file

@ -38,6 +38,38 @@ static int get_tty_path(int tty, char path[static TTYPATHLEN]) {
const size_t prefix_len = sizeof(prefix) - 1;
strcpy(path, prefix);
// The FreeBSD VT_GETACTIVE is implemented in the kernel as follows:
//
// static int
// vtterm_ioctl(struct terminal *tm, u_long cmd, caddr_t data,
// struct thread *td)
// {
// struct vt_window *vw = tm->tm_softc;
// struct vt_device *vd = vw->vw_device;
// ...
// switch (cmd) {
// ...
// case VT_GETACTIVE:
// *(int *)data = vd->vd_curwindow->vw_number + 1;
// return (0);
// ...
// }
// ...
// }
//
// The side-effect here being that the returned VT number is one
// greater than the internal VT number. The internal number is what is
// used to number the TTY device, while the external number is what we
// use in e.g. VT switching.
//
// We subtract one from the requested TTY number to compensate. If the
// user asked for TTY 0 (which is special on Linux), we just give them
// the first tty.
if (tty > 0) {
tty--;
}
// The FreeBSD tty name is constructed in the kernel as follows:
//
// static void
@ -139,35 +171,11 @@ int terminal_current_vt(int fd) {
return -1;
}
// The FreeBSD VT_GETACTIVE is implemented in the kernel as follows:
//
// static int
// vtterm_ioctl(struct terminal *tm, u_long cmd, caddr_t data,
// struct thread *td)
// {
// struct vt_window *vw = tm->tm_softc;
// struct vt_device *vd = vw->vw_device;
// ...
// switch (cmd) {
// ...
// case VT_GETACTIVE:
// *(int *)data = vd->vd_curwindow->vw_number + 1;
// return (0);
// ...
// }
// ...
// }
//
// The side-effect here being that the returned VT number is one
// greater than the internal VT number, which is what is used for e.g.
// numbering the associated VT. To simplify things, we subtract one
// from the returned VT number before returning it.
if (vt < 1) {
if (vt == -1) {
log_errorf("invalid vt: %d", vt);
return -1;
}
return vt - 1;
return vt;
#else
#error Unsupported platform
#endif