Attachment 69207 Details for Bug 56508 – don't memmove the last word

[patch] don't memmove the last word

MakeBigReq-move-less-2.patch (text/plain), 2.74 KB, created by Karl Tomlinson on 2012-10-29 04:48:24 UTC

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Creator: Karl Tomlinson

Created: 2012-10-29 04:48:24 UTC

Size: 2.74 KB

patch

obsolete

>From: Karl Tomlinson <xmail@karlt.net>
>Date: Wed, 24 Oct 2012 01:05:25 +0000
>Subject: MakeBigReq: don't move the last word, already handled by Data32
>
>The case where req->length = 1 was already not functional.
>Reported by Abhishek Arya <inferno@chromium.org>.
>https://bugzilla.mozilla.org/show_bug.cgi?id=803762
>
>Reviewed-by: Jeff Muizelaar <jmuizelaar@mozilla.com>
>--- libX11-1.5.0/include/X11/Xlibint.h	2012-10-24 12:36:48.768190632 +1300
>+++ libX11-1.5.0/include/X11/Xlibint.h	2012-10-26 10:49:05.498523215 +1300
>@@ -498,51 +498,66 @@ extern void *_XGetRequest(Display *dpy,
> #define GetEmptyReq(name, req) \
> 	req = (xReq *) _XGetRequest(dpy, X_##name, SIZEOF(xReq))
> #else
> #define GetEmptyReq(name, req) \
> 	req = (xReq *) _XGetRequest(dpy, X_/**/name, SIZEOF(xReq))
> #endif
> 
>+/*
>+ * MakeBigReq sets the CARD16 "req->length" to 0 and inserts a new CARD32
>+ * length, after req->length, before the data in the request.  The new length
>+ * includes the "n" extra 32-bit words.
>+ *
>+ * Do not use MakeBigReq if there is no data already in the request.
>+ * req->length must already be >= 2.
>+ */
> #ifdef WORD64
> #define MakeBigReq(req,n) \
>     { \
>     char _BRdat[4]; \
>     unsigned long _BRlen = req->length - 1; \
>     req->length = 0; \
>     memcpy(_BRdat, ((char *)req) + (_BRlen << 2), 4); \
>-    memmove(((char *)req) + 8, ((char *)req) + 4, _BRlen << 2); \
>+    memmove(((char *)req) + 8, ((char *)req) + 4, (_BRlen - 1) << 2); \
>     memcpy(((char *)req) + 4, _BRdat, 4); \
>     Data32(dpy, (long *)&_BRdat, 4); \
>     }
> #else
> #ifdef LONG64
> #define MakeBigReq(req,n) \
>     { \
>     CARD64 _BRdat; \
>     CARD32 _BRlen = req->length - 1; \
>     req->length = 0; \
>     _BRdat = ((CARD32 *)req)[_BRlen]; \
>-    memmove(((char *)req) + 8, ((char *)req) + 4, _BRlen << 2); \
>+    memmove(((char *)req) + 8, ((char *)req) + 4, (_BRlen - 1) << 2); \
>     ((CARD32 *)req)[1] = _BRlen + n + 2; \
>     Data32(dpy, &_BRdat, 4); \
>     }
> #else
> #define MakeBigReq(req,n) \
>     { \
>     CARD32 _BRdat; \
>     CARD32 _BRlen = req->length - 1; \
>     req->length = 0; \
>     _BRdat = ((CARD32 *)req)[_BRlen]; \
>-    memmove(((char *)req) + 8, ((char *)req) + 4, _BRlen << 2); \
>+    memmove(((char *)req) + 8, ((char *)req) + 4, (_BRlen - 1) << 2); \
>     ((CARD32 *)req)[1] = _BRlen + n + 2; \
>     Data32(dpy, &_BRdat, 4); \
>     }
> #endif
> #endif
> 
>+/*
>+ * SetReqLen increases the count of 32-bit words in the request by "n",
>+ * or by "badlen" if "n" is too large.
>+ *
>+ * Do not use SetReqLen if "req" does not already have data after the
>+ * xReq header.  req->length must already be >= 2.
>+ */
> #ifndef __clang_analyzer__
> #define SetReqLen(req,n,badlen) \
>     if ((req->length + n) > (unsigned)65535) { \
> 	if (dpy->bigreq_size) { \
> 	    MakeBigReq(req,n) \
> 	} else { \
> 	    n = badlen; \

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