nethack-gwaa-kiwi/nethack
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add some bullet-proofing to tabexpand()

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Include some bounds checking for tabexpand, but it assumes caller
passes a BUFSZ buffer rather than having that caller pass the actual
size.
This commit is contained in:
PatR
2020-01-04 03:33:57 -08:00
parent a018930964
commit 730b67b838
2 changed files with 25 additions and 8 deletions
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6
doc/fixes37.0
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@@ -1,4 +1,4 @@
$NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.40 $ $NHDT-Date: 1577674533 2019/12/30 02:55:33 $
$NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.43 $ $NHDT-Date: 1578137629 2020/01/04 11:33:49 $
General Fixes and Modified Features
-----------------------------------
@@ -89,3 +89,7 @@ more current Qt for Qt version 4 and 5 moved from win/Qt4 to win/Qt; qt4
moniker changed to qt_
window-port-interface: add_menu() modified to take a more general itemflags
parameter to support uses beyond just 'preselected'
add some bounds checking to tabexpand (doesn't prevent the apparent compiler
optimization bug that put homebrew OSX executable into endless loop)

27
src/hacklib.c
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@@ -1,4 +1,4 @@
/* NetHack 3.6 hacklib.c $NHDT-Date: 1574636502 2019/11/24 23:01:42 $ $NHDT-Branch: paxed-quest-lua $:$NHDT-Revision: 1.79 $ */
/* NetHack 3.6 hacklib.c $NHDT-Date: 1578137629 2020/01/04 11:33:49 $ $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.80 $ */
/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
/*-Copyright (c) Michael Allison, 2007. */
/* Copyright (c) Robert Patrick Rankin, 1991 */
@@ -416,27 +416,40 @@ const char *s;
return TRUE;
}
/* expand tabs into proper number of spaces */
/* expand tabs into proper number of spaces (in place) */
char *
tabexpand(sbuf)
char *sbuf;
char *sbuf; /* assumed to be [BUFSZ] but can be smaller provided that expanded
* string fits; expansion bigger than BUFSZ-1 will be truncated */
{
char buf[BUFSZ];
char buf[BUFSZ + 10];
register char *bp, *s = sbuf;
register int idx;
if (!*s)
return sbuf;
/* warning: no bounds checking performed */
for (bp = buf, idx = 0; *s; s++)
for (bp = buf, idx = 0; *s; s++) {
if (*s == '\t') {
/*
* clang-8's optimizer at -O4 has been observed to mis-compile
* this code when unrolling the loop. Symptom is nethack
* getting stuck in an apparent infinite loop (or perhaps just
* an extremely long one) when examining data.base entries.
* clang-9 doesn't exhibit this problem. [Was the incorrect
* optimization fixed or just disabled?]
*/
do
*bp++ = ' ';
while (++idx % 8);
} else {
*bp++ = *s;
idx++;
++idx;
}
if (idx >= BUFSZ) {
bp = &buf[BUFSZ - 1];
break;
}
}
*bp = 0;
return strcpy(sbuf, buf);
}