341 lines
8.5 KiB
C
341 lines
8.5 KiB
C
/* $NetBSD: memalloc.c,v 1.33 2019/02/09 03:35:55 kre Exp $ */
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/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Kenneth Almquist.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
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#else
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__RCSID("$NetBSD: memalloc.c,v 1.33 2019/02/09 03:35:55 kre Exp $");
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#endif
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#endif /* not lint */
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#include <stdlib.h>
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#include <unistd.h>
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#include "shell.h"
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#include "output.h"
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#include "memalloc.h"
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#include "error.h"
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#include "machdep.h"
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#include "mystring.h"
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/*
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* Like malloc, but returns an error when out of space.
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*/
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pointer
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ckmalloc(size_t nbytes)
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{
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pointer p;
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p = malloc(nbytes);
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if (p == NULL)
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error("Out of space");
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return p;
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}
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/*
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* Same for realloc.
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*/
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pointer
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ckrealloc(pointer p, int nbytes)
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{
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p = realloc(p, nbytes);
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if (p == NULL)
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error("Out of space");
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return p;
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}
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/*
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* Make a copy of a string in safe storage.
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*/
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char *
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savestr(const char *s)
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{
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char *p;
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p = ckmalloc(strlen(s) + 1);
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scopy(s, p);
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return p;
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}
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/*
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* Parse trees for commands are allocated in lifo order, so we use a stack
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* to make this more efficient, and also to avoid all sorts of exception
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* handling code to handle interrupts in the middle of a parse.
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*
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* The size 504 was chosen because the Ultrix malloc handles that size
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* well.
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*/
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#define MINSIZE 504 /* minimum size of a block */
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struct stack_block {
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struct stack_block *prev;
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char space[MINSIZE];
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};
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struct stack_block stackbase;
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struct stack_block *stackp = &stackbase;
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struct stackmark *markp;
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char *stacknxt = stackbase.space;
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int stacknleft = MINSIZE;
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int sstrnleft;
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int herefd = -1;
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pointer
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stalloc(int nbytes)
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{
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char *p;
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nbytes = SHELL_ALIGN(nbytes);
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if (nbytes > stacknleft) {
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int blocksize;
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struct stack_block *sp;
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blocksize = nbytes;
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if (blocksize < MINSIZE)
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blocksize = MINSIZE;
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INTOFF;
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sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize);
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sp->prev = stackp;
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stacknxt = sp->space;
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stacknleft = blocksize;
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stackp = sp;
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INTON;
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}
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INTOFF;
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p = stacknxt;
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stacknxt += nbytes;
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stacknleft -= nbytes;
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INTON;
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return p;
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}
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void
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stunalloc(pointer p)
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{
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if (p == NULL) { /*DEBUG */
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write(2, "stunalloc\n", 10);
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abort();
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}
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stacknleft += stacknxt - (char *)p;
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stacknxt = p;
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}
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/* save the current status of the sh stack */
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void
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setstackmark(struct stackmark *mark)
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{
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mark->stackp = stackp;
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mark->stacknxt = stacknxt;
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mark->stacknleft = stacknleft;
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mark->sstrnleft = sstrnleft;
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mark->marknext = markp;
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markp = mark;
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}
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/* reset the stack mark, and remove it from the list of marks */
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void
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popstackmark(struct stackmark *mark)
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{
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INTOFF;
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markp = mark->marknext; /* delete mark from the list */
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rststackmark(mark); /* and reset stack */
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INTON;
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}
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/* reset the shell stack to its state recorded in the stack mark */
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void
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rststackmark(struct stackmark *mark)
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{
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struct stack_block *sp;
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INTOFF;
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while (stackp != mark->stackp) {
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/* delete any recently allocated mem blocks */
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sp = stackp;
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stackp = sp->prev;
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ckfree(sp);
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}
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stacknxt = mark->stacknxt;
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stacknleft = mark->stacknleft;
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sstrnleft = mark->sstrnleft;
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INTON;
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}
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/*
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* When the parser reads in a string, it wants to stick the string on the
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* stack and only adjust the stack pointer when it knows how big the
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* string is. Stackblock (defined in stack.h) returns a pointer to a block
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* of space on top of the stack and stackblocklen returns the length of
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* this block. Growstackblock will grow this space by at least one byte,
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* possibly moving it (like realloc). Grabstackblock actually allocates the
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* part of the block that has been used.
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*/
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void
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growstackblock(void)
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{
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int newlen = SHELL_ALIGN(stacknleft * 2 + 100);
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INTOFF;
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if (stacknxt == stackp->space && stackp != &stackbase) {
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struct stack_block *oldstackp;
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struct stackmark *xmark;
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struct stack_block *sp;
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oldstackp = stackp;
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sp = stackp;
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stackp = sp->prev;
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sp = ckrealloc((pointer)sp,
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sizeof(struct stack_block) - MINSIZE + newlen);
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sp->prev = stackp;
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stackp = sp;
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stacknxt = sp->space;
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sstrnleft += newlen - stacknleft;
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stacknleft = newlen;
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/*
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* Stack marks pointing to the start of the old block
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* must be relocated to point to the new block
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*/
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xmark = markp;
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while (xmark != NULL && xmark->stackp == oldstackp) {
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xmark->stackp = stackp;
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xmark->stacknxt = stacknxt;
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xmark->sstrnleft += stacknleft - xmark->stacknleft;
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xmark->stacknleft = stacknleft;
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xmark = xmark->marknext;
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}
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} else {
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char *oldspace = stacknxt;
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int oldlen = stacknleft;
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char *p = stalloc(newlen);
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(void)memcpy(p, oldspace, oldlen);
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stacknxt = p; /* free the space */
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stacknleft += newlen; /* we just allocated */
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}
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INTON;
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}
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void
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grabstackblock(int len)
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{
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len = SHELL_ALIGN(len);
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INTOFF;
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stacknxt += len;
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stacknleft -= len;
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INTON;
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}
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/*
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* The following routines are somewhat easier to use than the above.
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* The user declares a variable of type STACKSTR, which may be declared
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* to be a register. The macro STARTSTACKSTR initializes things. Then
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* the user uses the macro STPUTC to add characters to the string. In
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* effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
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* grown as necessary. When the user is done, she can just leave the
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* string there and refer to it using stackblock(). Or she can allocate
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* the space for it using grabstackstr(). If it is necessary to allow
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* someone else to use the stack temporarily and then continue to grow
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* the string, the user should use grabstack to allocate the space, and
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* then call ungrabstr(p) to return to the previous mode of operation.
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*
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* USTPUTC is like STPUTC except that it doesn't check for overflow.
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* CHECKSTACKSPACE can be called before USTPUTC to ensure that there
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* is space for at least one character.
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*/
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char *
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growstackstr(void)
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{
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int len = stackblocksize();
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if (herefd >= 0 && len >= 1024) {
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xwrite(herefd, stackblock(), len);
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sstrnleft = len - 1;
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return stackblock();
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}
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growstackblock();
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sstrnleft = stackblocksize() - len - 1;
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return stackblock() + len;
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}
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/*
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* Called from CHECKSTRSPACE.
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*/
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char *
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makestrspace(void)
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{
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int len = stackblocksize() - sstrnleft;
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growstackblock();
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sstrnleft = stackblocksize() - len;
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return stackblock() + len;
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}
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/*
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* Note that this only works to release stack space for reuse
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* if nothing else has allocated space on the stack since the grabstackstr()
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*
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* "s" is the start of the area to be released, and "p" represents the end
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* of the string we have stored beyond there and are now releasing.
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* (ie: "p" should be the same as in the call to grabstackstr()).
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*
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* stunalloc(s) and ungrabstackstr(s, p) are almost interchangable after
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* a grabstackstr(), however the latter also returns string space so we
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* can just continue with STPUTC() etc without needing a new STARTSTACKSTR(s)
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*/
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void
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ungrabstackstr(char *s, char *p)
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{
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#ifdef DEBUG
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if (s < stacknxt || stacknxt + stacknleft < s)
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abort();
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#endif
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stacknleft += stacknxt - s;
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stacknxt = s;
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sstrnleft = stacknleft - (p - s);
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}
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