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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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);
}