freebsd-src/bin/sh/memalloc.h
David E. O'Brien 7cfe69417c Do not assume in growstackstr() that a "precious" character will be
immediately written into the stack after the call.  Instead let the caller
manage the "space left".

Previously, growstackstr()'s assumption causes problems with STACKSTRNUL()
where we want to be able to turn a stack into a C string, and later
pretend the NUL is not there.

This fixes a bug in STACKSTRNUL() (that grew the stack) where:
1. STADJUST() called after a STACKSTRNUL() results in an improper adjust.
   This can be seen in ${var%pattern} and ${var%%pattern} evaluation.
2. Memory leak in STPUTC() called after a STACKSTRNUL().

Reviewed by:	jilles
2010-10-13 23:29:09 +00:00

85 lines
3.2 KiB
C

/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)memalloc.h 8.2 (Berkeley) 5/4/95
* $FreeBSD$
*/
#include <string.h>
struct stackmark {
struct stack_block *stackp;
char *stacknxt;
int stacknleft;
struct stackmark *marknext;
};
extern char *stacknxt;
extern int stacknleft;
extern int sstrnleft;
extern int herefd;
pointer ckmalloc(size_t);
pointer ckrealloc(pointer, int);
void ckfree(pointer);
char *savestr(const char *);
pointer stalloc(int);
void stunalloc(pointer);
void setstackmark(struct stackmark *);
void popstackmark(struct stackmark *);
void growstackblock(void);
void grabstackblock(int);
char *growstackstr(void);
char *makestrspace(void);
void ungrabstackstr(char *, char *);
#define stackblock() stacknxt
#define stackblocksize() stacknleft
#define STARTSTACKSTR(p) p = stackblock(), sstrnleft = stackblocksize()
#define STPUTC(c, p) (--sstrnleft >= 0? (*p++ = (c)) : (p = growstackstr(), --sstrnleft, *p++ = (c)))
#define CHECKSTRSPACE(n, p) { if (sstrnleft < n) p = makestrspace(); }
#define USTPUTC(c, p) (--sstrnleft, *p++ = (c))
/*
* STACKSTRNUL's use is where we want to be able to turn a stack
* (non-sentinel, character counting string) into a C string,
* and later pretend the NUL is not there.
* Note: Because of STACKSTRNUL's semantics, STACKSTRNUL cannot be used
* on a stack that will grabstackstr()ed.
*/
#define STACKSTRNUL(p) (sstrnleft == 0? (p = growstackstr(), *p = '\0') : (*p = '\0'))
#define STUNPUTC(p) (++sstrnleft, --p)
#define STTOPC(p) p[-1]
#define STADJUST(amount, p) (p += (amount), sstrnleft -= (amount))
#define grabstackstr(p) stalloc(stackblocksize() - sstrnleft)