[PATCH xserver 2/6] xfree86: Remove xf86InterceptSignals

[Olivier Fourdan]

On Mon, Nov 20, 2017 at 9:43 PM, Adam Jackson <ajax at redhat.com> wrote:

> The only consumer of this is the Linux vm86 backend for int10 (which you
> should not use), and there all it serves to do is make signals generated
> by the vm86 task non-fatal. In practice this error appears never to
> happen, and marching ahead with root privileges after arbitrary code has
> raised a signal seems like a poor plan.
>
> Remove the usage in the vm86 code, making this error fatal.
>
> Signed-off-by: Adam Jackson <ajax at redhat.com>
> ---
>  hw/xfree86/common/xf86.h                            |  1 -
>  hw/xfree86/common/xf86Events.c                      | 14 --------------
>  hw/xfree86/os-support/linux/int10/vm86/linux_vm86.c | 13 +------------
>  3 files changed, 1 insertion(+), 27 deletions(-)
>
> diff --git a/hw/xfree86/common/xf86.h b/hw/xfree86/common/xf86.h
> index db6e299b31..43b693143e 100644
> --- a/hw/xfree86/common/xf86.h
> +++ b/hw/xfree86/common/xf86.h
> @@ -215,7 +215,6 @@ extern _X_EXPORT void xf86DisableGeneralHandler(void
> *handler);
>  extern _X_EXPORT void xf86EnableGeneralHandler(void *handler);
>  extern _X_EXPORT InputHandlerProc xf86SetConsoleHandler(InputHandlerProc
>                                                          handler, void
> *data);
> -extern _X_EXPORT void xf86InterceptSignals(int *signo);
>  extern _X_EXPORT void xf86ProcessActionEvent(ActionEvent action, void
> *arg);
>  extern _X_EXPORT void xf86PrintBacktrace(void);
>  extern _X_EXPORT Bool xf86VTOwner(void);
> diff --git a/hw/xfree86/common/xf86Events.c b/hw/xfree86/common/
> xf86Events.c
> index e2e6ca7691..a27c7ff1b0 100644
> --- a/hw/xfree86/common/xf86Events.c
> +++ b/hw/xfree86/common/xf86Events.c
> @@ -267,15 +267,6 @@ xf86RemoveEnabledDevice(InputInfoPtr pInfo)
>      InputThreadUnregisterDev(pInfo->fd);
>  }
>
> -static int *xf86SignalIntercept = NULL;
> -
> -void
> -xf86InterceptSignals(int *signo)
> -{
> -    if ((xf86SignalIntercept = signo))
> -        *signo = -1;
> -}
> -
>  /*
>   * xf86SigWrapper --
>   *    Catch unexpected signals and exit or continue cleanly.
> @@ -283,11 +274,6 @@ xf86InterceptSignals(int *signo)
>  int
>  xf86SigWrapper(int signo)
>  {
> -    if (xf86SignalIntercept && (*xf86SignalIntercept < 0)) {
> -        *xf86SignalIntercept = signo;
> -        return 0;               /* continue */
> -    }
> -
>      xf86Info.caughtSignal = TRUE;
>      return 1;                   /* abort */
>  }
> diff --git a/hw/xfree86/os-support/linux/int10/vm86/linux_vm86.c
> b/hw/xfree86/os-support/linux/int10/vm86/linux_vm86.c
> index 1876983991..134809814f 100644
> --- a/hw/xfree86/os-support/linux/int10/vm86/linux_vm86.c
> +++ b/hw/xfree86/os-support/linux/int10/vm86/linux_vm86.c
> @@ -231,20 +231,9 @@ vm86_GP_fault(xf86Int10InfoPtr pInt)
>  static int
>  do_vm86(xf86Int10InfoPtr pInt)
>  {
> -    int retval, signo;
> +    int retval;
>
> -    xf86InterceptSignals(&signo);
>      retval = vm86_rep(VM86S);
> -    xf86InterceptSignals(NULL);
> -
> -    if (signo >= 0) {
> -        xf86DrvMsg(pInt->pScrn->scrnIndex, X_ERROR,
> -                   "vm86() syscall generated signal %d.\n", signo);
> -        dump_registers(pInt);
> -        dump_code(pInt);
> -        stack_trace(pInt);
> -        return 0;
> -    }
>
>      switch (VM86_TYPE(retval)) {
>      case VM86_UNKNOWN:
> --
> 2.14.3
>
> _______________________________________________
> xorg-devel at lists.x.org: X.Org development
> Archives: http://lists.x.org/archives/xorg-devel
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I can't tell whether or not this happens in practice, but for the code
part, this is:

Reviewed-by: Olivier Fourdan <ofourdan at redhat.com>
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