Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!purdue!haven!mimsy!chris
From: chris@mimsy.umd.edu (Chris Torek)
Newsgroups: comp.unix.wizards
Subject: Re: free() boundary checking
Keywords: free,memory
Message-ID: <23016@mimsy.umd.edu>
Date: 10 Mar 90 06:37:23 GMT
References: <25@nixeid.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 16

In article <25@nixeid.UUCP> keogh@nixeid.UUCP (Paul Keogh) writes:
>... code ... lifted from the csh source ... would crash ... [in] malloc ...
>... equivalent csh code called a routine called xfree():

[with] xfree(c) char *c; { if (c >= end && c < (char *) &c) free(c); }

>Why is this check necessary?

The check is necessary because Bill Joy was lazy.

The csh globbing code is wrong (or, if you prefer, `machine dependent').
xfree() is a hack to compensate for this.

-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@cs.umd.edu	Path:	uunet!mimsy!chris