freebsd-skq/bin/sh/memalloc.h
jilles e0dffd814f sh: Remove linked list of stack marks.
The linked list of stack marks may cause problems if the allocation stack is
used between an exception and a higher-level popstackmark(), as it may then
touch a stack mark that is local to a function which has returned.

Also, the adjustment compares to a pointer passed to realloc(), which is
undefined behaviour.

Instead of adjusting stack marks when reallocating stack blocks, ensure that
such an adjustment is never necessary by fixing a small piece of memory in
place at a stack mark. This also simplifies the code.

To avoid the problems reported in bin/175922, it remains necessary to call
setstackmark() after popstackmark() if the stack mark remains in use.
2013-05-11 20:51:00 +00:00

86 lines
3.3 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;
};
extern char *stacknxt;
extern int stacknleft;
extern char *sstrend;
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 *);
char *growstackstr(void);
char *makestrspace(int, char *);
char *stputbin(const char *data, size_t len, char *p);
char *stputs(const char *data, char *p);
#define stackblock() stacknxt
#define stackblocksize() stacknleft
#define grabstackblock(n) stalloc(n)
#define STARTSTACKSTR(p) p = stackblock()
#define STPUTC(c, p) do { if (p == sstrend) p = growstackstr(); *p++ = (c); } while(0)
#define CHECKSTRSPACE(n, p) { if ((size_t)(sstrend - p) < n) p = makestrspace(n, p); }
#define USTPUTC(c, p) (*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) (p == sstrend ? (p = growstackstr(), *p = '\0') : (*p = '\0'))
#define STUNPUTC(p) (--p)
#define STTOPC(p) p[-1]
#define STADJUST(amount, p) (p += (amount))
#define grabstackstr(p) stalloc((char *)p - stackblock())
#define ungrabstackstr(s, p) stunalloc((s))
#define STPUTBIN(s, len, p) p = stputbin((s), (len), p)
#define STPUTS(s, p) p = stputs((s), p)