101 строка
3.8 KiB
Diff
101 строка
3.8 KiB
Diff
From f3079e509c5cf60042ae2261499ee13b6b02498a Mon Sep 17 00:00:00 2001
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From: Adam Jackson <ajax@redhat.com>
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Date: Thu, 6 Feb 2020 13:45:35 -0500
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Subject: [PATCH] xt: Work around a compiler issue with gcc 10
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GRABEXT() is used to look up a pointer that sometimes lives just past
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the end of an XtServerGrabRec. Whether it's really there or not depends
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on XtServerGrabRec::hasExt. In a couple of places, we build those
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structs on the stack and pass them to other functions; such structs
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always have hasExt == 0, so GRABEXT would never get called in practice.
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However, there exists a bug in gcc 10 - more or less difficult to hit,
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depending on your compiler options and architecture - where it would not
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notice that the dereference after GRABEXT is dead code, at which point
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it looks like you're dereferencing one past the end of the array, which
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is illegal, and you you get:
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PassivGrab.c:292:35: error: array subscript 0 is outside array bounds
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of 'XtServerGrabRec[1]' {aka 'struct _XtServerGrabRec[1]'}
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[-Werror=array-bounds]
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As a completely stupid workaround, build those on-stack structs as
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arrays of two, so that the (dead) dereference looks like it's pointing
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into the dummy member of the array. This is almost certainly a compiler
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bug and I don't encourage merging this patch upstream, but if you need
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to build libXt with gcc 10 absolutely right this second, here it is.
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For details on the gcc issue, see:
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93582
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---
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src/PassivGrab.c | 24 ++++++++++++------------
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1 file changed, 12 insertions(+), 12 deletions(-)
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diff --git a/src/PassivGrab.c b/src/PassivGrab.c
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index bece0d9..b174d40 100644
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--- a/src/PassivGrab.c
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+++ b/src/PassivGrab.c
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@@ -553,7 +553,7 @@ XtServerGrabPtr _XtCheckServerGrabsOnWidget (
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_XtBoolean isKeyboard)
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{
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register XtServerGrabPtr grab;
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- XtServerGrabRec tempGrab;
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+ XtServerGrabRec tempGrab[2];
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XtServerGrabPtr *passiveListPtr;
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XtPerWidgetInput pwi;
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@@ -577,13 +577,13 @@ XtServerGrabPtr _XtCheckServerGrabsOnWidget (
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/* Take only the lower thirteen bits as modifier state. The X Keyboard
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* Extension may be representing keyboard group state in two upper bits.
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*/
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- tempGrab.widget = widget;
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- tempGrab.keybut = (KeyCode) event->xkey.keycode; /* also xbutton.button */
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- tempGrab.modifiers = event->xkey.state & 0x1FFF; /*also xbutton.state*/
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- tempGrab.hasExt = False;
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+ tempGrab[0].widget = widget;
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+ tempGrab[0].keybut = (KeyCode) event->xkey.keycode; /* also xbutton.button */
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+ tempGrab[0].modifiers = event->xkey.state & 0x1FFF; /*also xbutton.state*/
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+ tempGrab[0].hasExt = False;
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for (grab = *passiveListPtr; grab; grab = grab->next) {
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- if (GrabMatchesSecond(&tempGrab, grab))
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+ if (GrabMatchesSecond(tempGrab, grab))
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return (grab);
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}
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return (XtServerGrabPtr)NULL;
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@@ -775,17 +775,17 @@ void UngrabKeyOrButton (
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Modifiers modifiers,
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Boolean isKeyboard)
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{
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- XtServerGrabRec tempGrab;
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+ XtServerGrabRec tempGrab[2];
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XtPerWidgetInput pwi;
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XtCheckSubclass(widget, coreWidgetClass,
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"in XtUngrabKey or XtUngrabButton");
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/* Build a temporary grab list entry */
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- tempGrab.widget = widget;
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- tempGrab.modifiers = (unsigned short) modifiers;
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- tempGrab.keybut = (KeyCode) keyOrButton;
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- tempGrab.hasExt = False;
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+ tempGrab[0].widget = widget;
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+ tempGrab[0].modifiers = (unsigned short) modifiers;
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+ tempGrab[0].keybut = (KeyCode) keyOrButton;
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+ tempGrab[0].hasExt = False;
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LOCK_PROCESS;
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pwi = _XtGetPerWidgetInput(widget, FALSE);
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@@ -817,7 +817,7 @@ void UngrabKeyOrButton (
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/* Delete all entries which are encompassed by the specified grab. */
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DeleteServerGrabFromList(isKeyboard ? &pwi->keyList : &pwi->ptrList,
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- &tempGrab);
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+ tempGrab);
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}
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void XtGrabKey (
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--
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2.23.0
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