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randr: skip payload assembly in ProcRRGetScreenInfo() no data to send 

If there's no data to send, the whole reply payload can be skipped entirely.
This can also ease the whole code flow, and we don't need to rely on the
individual copy loops never trying to dereference a NULL pointer.
(what the analyzer can't proof). Also scoping several some variables that
are only used when there actually is data to send.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
This commit is contained in:
Enrico Weigelt, metux IT consult 2025-05-13 16:46:20 +02:00
parent 74a3b2b728
commit 90cd5c38ee
1 changed files with 12 additions and 13 deletions
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19
randr/rrscreen.c
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@ -774,8 +774,6 @@ ProcRRGetScreenInfo(ClientPtr client)
}
else {
int i, j;
xScreenSizes *size;
CARD16 *rates;
CARD8 *data8;
Bool has_rate = RRClientKnowsRates(client);
RR10DataPtr pData;
@ -803,21 +801,20 @@ ProcRRGetScreenInfo(ClientPtr client)
if (has_rate)
extraLen += rep.nrateEnts * sizeof(CARD16);
if (extraLen) {
extra = (CARD8 *) malloc(extraLen);
if (!extraLen)
goto finish; // no extra payload
extra = calloc(1, extraLen);
if (!extra) {
free(pData);
return BadAlloc;
}
}
else
extra = NULL;
/*
* First comes the size information
*/
size = (xScreenSizes *) extra;
rates = (CARD16 *) (size + rep.nSizes);
xScreenSizes *size = (xScreenSizes *) extra;
CARD16 *rates = (CARD16 *) (size + rep.nSizes);
for (i = 0; i < pData->nsize; i++) {
pSize = &pData->sizes[i];
size->widthInPixels = pSize->width;
@ -846,7 +843,6 @@ ProcRRGetScreenInfo(ClientPtr client)
}
}
}
free(pData);
data8 = (CARD8 *) rates;
@ -854,6 +850,9 @@ ProcRRGetScreenInfo(ClientPtr client)
FatalError("RRGetScreenInfo bad extra len %ld != %ld\n",
(unsigned long) (data8 - (CARD8 *) extra), extraLen);
rep.length = bytes_to_int32(extraLen);
finish:
free(pData);
}
if (client->swapped) {
swaps(&rep.sequenceNumber);