/* $NetBSD: memalloc.c,v 1.32 2018/08/22 20:08:54 kre Exp $ */
/*-
* 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.
* 3. 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.
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: memalloc.c,v 1.32 2018/08/22 20:08:54 kre Exp $");
#endif
#endif /* not lint */
#include <stdlib.h>
#include <unistd.h>
#include "shell.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#include "machdep.h"
#include "mystring.h"
/*
* Like malloc, but returns an error when out of space.
*/
pointer
ckmalloc(size_t nbytes)
{
pointer p;
p = malloc(nbytes);
if (p == NULL)
error("Out of space");
return p;
}
/*
* Same for realloc.
*/
pointer
ckrealloc(pointer p, int nbytes)
{
p = realloc(p, nbytes);
if (p == NULL)
error("Out of space");
return p;
}
/*
* Make a copy of a string in safe storage.
*/
char *
savestr(const char *s)
{
char *p;
p = ckmalloc(strlen(s) + 1);
scopy(s, p);
return p;
}
/*
* Parse trees for commands are allocated in lifo order, so we use a stack
* to make this more efficient, and also to avoid all sorts of exception
* handling code to handle interrupts in the middle of a parse.
*
* The size 504 was chosen because the Ultrix malloc handles that size
* well.
*/
#define MINSIZE 504 /* minimum size of a block */
struct stack_block {
struct stack_block *prev;
char space[MINSIZE];
};
struct stack_block stackbase;
struct stack_block *stackp = &stackbase;
struct stackmark *markp;
char *stacknxt = stackbase.space;
int stacknleft = MINSIZE;
int sstrnleft;
int herefd = -1;
pointer
stalloc(int nbytes)
{
char *p;
nbytes = SHELL_ALIGN(nbytes);
if (nbytes > stacknleft) {
int blocksize;
struct stack_block *sp;
blocksize = nbytes;
if (blocksize < MINSIZE)
blocksize = MINSIZE;
INTOFF;
sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize);
sp->prev = stackp;
stacknxt = sp->space;
stacknleft = blocksize;
stackp = sp;
INTON;
}
p = stacknxt;
stacknxt += nbytes;
stacknleft -= nbytes;
return p;
}
void
stunalloc(pointer p)
{
if (p == NULL) { /*DEBUG */
write(2, "stunalloc\n", 10);
abort();
}
stacknleft += stacknxt - (char *)p;
stacknxt = p;
}
/* save the current status of the sh stack */
void
setstackmark(struct stackmark *mark)
{
mark->stackp = stackp;
mark->stacknxt = stacknxt;
mark->stacknleft = stacknleft;
mark->sstrnleft = sstrnleft;
mark->marknext = markp;
markp = mark;
}
/* reset the stack mark, and remove it from the list of marks */
void
popstackmark(struct stackmark *mark)
{
markp = mark->marknext; /* delete mark from the list */
rststackmark(mark); /* and reset stack */
}
/* reset the shell stack to its state recorded in the stack mark */
void
rststackmark(struct stackmark *mark)
{
struct stack_block *sp;
INTOFF;
while (stackp != mark->stackp) {
/* delete any recently allocated mem blocks */
sp = stackp;
stackp = sp->prev;
ckfree(sp);
}
stacknxt = mark->stacknxt;
stacknleft = mark->stacknleft;
sstrnleft = mark->sstrnleft;
INTON;
}
/*
* When the parser reads in a string, it wants to stick the string on the
* stack and only adjust the stack pointer when it knows how big the
* string is. Stackblock (defined in stack.h) returns a pointer to a block
* of space on top of the stack and stackblocklen returns the length of
* this block. Growstackblock will grow this space by at least one byte,
* possibly moving it (like realloc). Grabstackblock actually allocates the
* part of the block that has been used.
*/
void
growstackblock(void)
{
int newlen = SHELL_ALIGN(stacknleft * 2 + 100);
INTOFF;
if (stacknxt == stackp->space && stackp != &stackbase) {
struct stack_block *oldstackp;
struct stackmark *xmark;
struct stack_block *sp;
oldstackp = stackp;
sp = stackp;
stackp = sp->prev;
sp = ckrealloc((pointer)sp,
sizeof(struct stack_block) - MINSIZE + newlen);
sp->prev = stackp;
stackp = sp;
stacknxt = sp->space;
sstrnleft += newlen - stacknleft;
stacknleft = newlen;
/*
* Stack marks pointing to the start of the old block
* must be relocated to point to the new block
*/
xmark = markp;
while (xmark != NULL && xmark->stackp == oldstackp) {
xmark->stackp = stackp;
xmark->stacknxt = stacknxt;
xmark->sstrnleft += stacknleft - xmark->stacknleft;
xmark->stacknleft = stacknleft;
xmark = xmark->marknext;
}
} else {
char *oldspace = stacknxt;
int oldlen = stacknleft;
char *p = stalloc(newlen);
(void)memcpy(p, oldspace, oldlen);
stacknxt = p; /* free the space */
stacknleft += newlen; /* we just allocated */
}
INTON;
}
void
grabstackblock(int len)
{
len = SHELL_ALIGN(len);
stacknxt += len;
stacknleft -= len;
}
/*
* The following routines are somewhat easier to use than the above.
* The user declares a variable of type STACKSTR, which may be declared
* to be a register. The macro STARTSTACKSTR initializes things. Then
* the user uses the macro STPUTC to add characters to the string. In
* effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
* grown as necessary. When the user is done, she can just leave the
* string there and refer to it using stackblock(). Or she can allocate
* the space for it using grabstackstr(). If it is necessary to allow
* someone else to use the stack temporarily and then continue to grow
* the string, the user should use grabstack to allocate the space, and
* then call ungrabstr(p) to return to the previous mode of operation.
*
* USTPUTC is like STPUTC except that it doesn't check for overflow.
* CHECKSTACKSPACE can be called before USTPUTC to ensure that there
* is space for at least one character.
*/
char *
growstackstr(void)
{
int len = stackblocksize();
if (herefd >= 0 && len >= 1024) {
xwrite(herefd, stackblock(), len);
sstrnleft = len - 1;
return stackblock();
}
growstackblock();
sstrnleft = stackblocksize() - len - 1;
return stackblock() + len;
}
/*
* Called from CHECKSTRSPACE.
*/
char *
makestrspace(void)
{
int len = stackblocksize() - sstrnleft;
growstackblock();
sstrnleft = stackblocksize() - len;
return stackblock() + len;
}
/*
* Note that this only works to release stack space for reuse
* if nothing else has allocated space on the stack since the grabstackstr()
*
* "s" is the start of the area to be released, and "p" represents the end
* of the string we have stored beyond there and are now releasing.
* (ie: "p" should be the same as in the call to grabstackstr()).
*
* stunalloc(s) and ungrabstackstr(s, p) are almost interchangable after
* a grabstackstr(), however the latter also returns string space so we
* can just continue with STPUTC() etc without needing a new STARTSTACKSTR(s)
*/
void
ungrabstackstr(char *s, char *p)
{
#ifdef DEBUG
if (s < stacknxt || stacknxt + stacknleft < s)
abort();
#endif
stacknleft += stacknxt - s;
stacknxt = s;
sstrnleft = stacknleft - (p - s);
}
