source: trunk/src/kash/memalloc.c@ 3458

/*      $NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc 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.
 */

#if 0
#ifndef lint
static char sccsid[] = "@(#)memalloc.c  8.3 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc Exp $");
#endif /* not lint */
#endif

#include <stdlib.h>
#include <stddef.h>
#include <assert.h>

#include "shell.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#include "machdep.h"
#include "mystring.h"
#include "shinstance.h"
#include "nodes.h"

/*
 * Like malloc, but returns an error when out of space.
 */

pointer
ckmalloc(shinstance *psh, size_t nbytes)
{
        pointer p;

        p = sh_malloc(psh, nbytes);
        if (p == NULL)
                error(psh, "Out of space");
        return p;
}


/*
 * Same for realloc.
 */

pointer
ckrealloc(struct shinstance *psh, pointer p, size_t nbytes)
{
        p = sh_realloc(psh, p, nbytes);
        if (p == NULL)
                error(psh, "Out of space");
        return p;
}


/*
 * Make a copy of a string in safe storage.
 */

char *
savestr(struct shinstance *psh, const char *s)
{
        char *p;
        size_t len = strlen(s);

        p = ckmalloc(psh, len + 1);
        memcpy(p, s, len + 1);
        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(shinstance *psh, size_t nbytes)
{
        char *p;

        nbytes = SHELL_ALIGN(nbytes);
        if (nbytes > (size_t)psh->stacknleft || psh->stacknleft < 0) {
                size_t blocksize;
                struct stack_block *sp;

                blocksize = nbytes;
                if (blocksize < MINSIZE)
                        blocksize = MINSIZE;
                INTOFF;
                sp = ckmalloc(psh, sizeof(struct stack_block) - MINSIZE + blocksize);
                sp->prev = psh->stackp;
                psh->stacknxt = sp->space;
                psh->stacknleft = (int)blocksize;
                psh->stackp = sp;
                INTON;
        }
        p = psh->stacknxt;
        psh->stacknxt += nbytes;
        psh->stacknleft -= (int)nbytes;
        return p;
}


char *
stsavestr(struct shinstance *psh, const char *src)
{
        if (src) {
                size_t size = strlen(src) + 1;
                char *dst = (char *)stalloc(psh, size);
                return (char *)memcpy(dst, src, size);
        }
        return NULL;
}


void
stunalloc(shinstance *psh, pointer p)
{
        if (p == NULL) {                /*DEBUG */
                shfile_write(&psh->fdtab, 2, "stunalloc\n", 10);
                sh_abort(psh);
        }
        psh->stacknleft += (int)(psh->stacknxt - (char *)p);
        psh->stacknxt = p;
}



void
setstackmark(shinstance *psh, struct stackmark *mark)
{
        mark->stackp = psh->stackp;
        mark->stacknxt = psh->stacknxt;
        mark->stacknleft = psh->stacknleft;
        mark->marknext = psh->markp;
#ifdef KASH_SEPARATE_PARSER_ALLOCATOR
        mark->pstacksize = psh->pstacksize;
#endif
        psh->markp = mark;
}


void
popstackmark(shinstance *psh, struct stackmark *mark)
{
        struct stack_block *sp;

        INTOFF;
        psh->markp = mark->marknext;
        while (psh->stackp != mark->stackp) {
                sp = psh->stackp;
                psh->stackp = sp->prev;
                ckfree(psh, sp);
        }
        psh->stacknxt = mark->stacknxt;
        psh->stacknleft = mark->stacknleft;

#ifdef KASH_SEPARATE_PARSER_ALLOCATOR
        pstackpop(psh, mark->pstacksize);
#endif
        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(shinstance *psh)
{
        int newlen = SHELL_ALIGN(psh->stacknleft * 2 + 100);

        if (psh->stacknxt == psh->stackp->space && psh->stackp != &psh->stackbase) {
                struct stack_block *oldstackp;
                struct stackmark *xmark;
                struct stack_block *sp;

                INTOFF;
                oldstackp = psh->stackp;
                sp = psh->stackp;
                psh->stackp = sp->prev;
                sp = ckrealloc(psh, (pointer)sp,
                    sizeof(struct stack_block) - MINSIZE + newlen);
                sp->prev = psh->stackp;
                psh->stackp = sp;
                psh->stacknxt = sp->space;
                psh->stacknleft = newlen;

                /*
                 * Stack marks pointing to the start of the old block
                 * must be relocated to point to the new block
                 */
                xmark = psh->markp;
                while (xmark != NULL && xmark->stackp == oldstackp) {
                        xmark->stackp = psh->stackp;
                        xmark->stacknxt = psh->stacknxt;
                        xmark->stacknleft = psh->stacknleft;
                        xmark = xmark->marknext;
                }
                INTON;
        } else {
                char *oldspace = psh->stacknxt;
                int oldlen = psh->stacknleft;
                char *p = stalloc(psh, newlen);

                (void)memcpy(p, oldspace, oldlen);
                psh->stacknxt = p;                      /* free the space */
                psh->stacknleft += newlen;              /* we just allocated */
        }
}

void
grabstackblock(shinstance *psh, int len)
{
        len = SHELL_ALIGN(len);
        psh->stacknxt += len;
        psh->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(psh, 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(psh).  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(shinstance *psh)
{
        int len = stackblocksize(psh);
        if (psh->herefd >= 0 && len >= 1024) {
                xwrite(psh, psh->herefd, stackblock(psh), len);
                psh->sstrnleft = len - 1;
                return stackblock(psh);
        }
        growstackblock(psh);
        psh->sstrnleft = stackblocksize(psh) - len - 1;
        return stackblock(psh) + len;
}

/*
 * Called from CHECKSTRSPACE.
 */

char *
makestrspace(shinstance *psh)
{
        int len = stackblocksize(psh) - psh->sstrnleft;
        growstackblock(psh);
        psh->sstrnleft = stackblocksize(psh) - len;
        return stackblock(psh) + len;
}


/*
 * Got better control having a dedicated function for this.
 *
 * Was: #define grabstackstr(psh, p)   stalloc((psh), stackblocksize(psh) - (psh)->sstrnleft)
 */
char *
grabstackstr(shinstance *psh, char *end)
{
        char * const pstart = stackblock(psh);
        size_t nbytes = (size_t)(end - pstart);

        assert((uintptr_t)end >= (uintptr_t)pstart);
        /*assert(end[-1] == '\0'); - not if it's followed by ungrabstrackstr(), sigh. */
        assert(SHELL_ALIGN((uintptr_t)pstart) == (uintptr_t)pstart);
        assert(stackblocksize(psh) - psh->sstrnleft >= nbytes);

        nbytes = SHELL_ALIGN(nbytes);
        psh->stacknxt += nbytes;
        psh->stacknleft -= (int)nbytes;
        assert(psh->stacknleft >= 0);

        return pstart;
}

void
ungrabstackstr(shinstance *psh, char *s, char *p)
{
        assert((size_t)(psh->stacknxt - p) <= SHELL_SIZE);
        assert((uintptr_t)s >= (uintptr_t)&psh->stackp->space[0]);
        assert((uintptr_t)p >= (uintptr_t)s);

        psh->stacknleft += (int)(psh->stacknxt - s);
        psh->stacknxt = s;
        psh->sstrnleft = (int)(psh->stacknleft - (p - s));

}


/*
 * Parser stack allocator.
 */
#ifdef KASH_SEPARATE_PARSER_ALLOCATOR

unsigned pstackrelease(shinstance *psh, pstack_block *pst, const char *caller)
{
        unsigned refs;
        if (pst) {
                refs = sh_atomic_dec(&pst->refs);
                TRACE2((NULL, "pstackrelease: %p - %u refs (%s)\n", pst, refs, caller)); K_NOREF(caller);
                if (refs == 0) {
                        shinstance * const psh = shthread_get_shell();
                        struct stack_block *top;
                        while ((top = pst->top) != &pst->first)
                        {
                            pst->top = top->prev;
                            assert(pst->top);
                            top->prev = NULL;
                            sh_free(psh, top);
                        }
                        pst->nextbyte = NULL;
                        pst->top = NULL;
                        /** @todo push into an alloc cache rather than freeing it */
                        sh_free(psh, pst);
                }
        } else
                refs = 0;
        return refs;
}

void pstackpop(shinstance *psh, unsigned target)
{
        assert(target <= psh->pstacksize);
        while (target < psh->pstacksize) {
                unsigned idx = --psh->pstacksize;
                pstack_block *psk = psh->pstack[idx];
                psh->pstack[idx] = NULL;
                if (psh->curpstack == psk)
                    psh->curpstack = idx > 0 ? psh->pstack[idx - 1] : NULL;
                pstackrelease(psh, psk, "popstackmark");
        }

# ifndef NDEBUG
        if (psh->curpstack) {
                unsigned i;
                for (i = 0; i < psh->pstacksize; i++)
                        if (psh->curpstack == psh->pstack[i])
                                break;
                assert(i < psh->pstacksize);
        }
# endif
}


unsigned pstackretain(pstack_block *pst)
{
        unsigned refs = sh_atomic_inc(&pst->refs);
        assert(refs > 1);
        assert(refs < 256 /* bogus, but useful */);
        return refs;
}

K_INLINE void pstackpush(shinstance *psh, pstack_block *pst)
{
        unsigned i = psh->pstacksize;
        if (i + 1 < psh->pstackalloced) {
                /* likely, except for the first time */
        } else {
                psh->pstack = (pstack_block **)ckrealloc(psh, psh->pstack, sizeof(psh->pstack[0]) * (i + 32));
                memset(&psh->pstack[i], 0, sizeof(psh->pstack[0]) * 32);
        }
        psh->pstack[i] = pst;
        psh->pstacksize = i + 1;
}

/* Does not make it current! */
unsigned pstackretainpush(shinstance *psh, pstack_block *pst)
{
        unsigned refs = pstackretain(pst);
        pstackpush(psh, pst);
        TRACE2((psh, "pstackretainpush: %p - entry %u - %u refs\n", pst, psh->pstacksize - 1, refs));
        return refs;
}

pstack_block *pstackallocpush(shinstance *psh)
{
        size_t const blocksize = offsetof(pstack_block, first.space) + MINSIZE;
        pstack_block *pst;

        INTOFF;

        /*
         * Allocate and initialize it.
         */
        pst = (pstack_block *)ckmalloc(psh, blocksize);
        pst->nextbyte          = &pst->first.space[0];
        pst->avail             = blocksize - offsetof(pstack_block, first.space);
        pst->topsize           = blocksize - offsetof(pstack_block, first.space);
        pst->strleft           = 0;
        pst->top               = &pst->first;
        pst->allocations       = 0;
        pst->bytesalloced      = 0;
        pst->nodesalloced      = 0;
        pst->entriesalloced    = 0;
        pst->strbytesalloced   = 0;
        pst->blocks            = 0;
        pst->fragmentation     = 0;
        pst->refs              = 1;
        pst->padding           = 42;
        pst->first.prev        = NULL;

        /*
         * Push it onto the stack and make it current.
         */
        pstackpush(psh, pst);
        psh->curpstack = pst;

        INTON;
        TRACE2((psh, "pstackallocpush: %p - entry %u\n", pst, psh->pstacksize - 1));
        return pst;
}

/**
 * Allocates and pushes a new block onto the stack, min payload size @a nbytes.
 */
static void pstallocnewblock(shinstance *psh, pstack_block *pst, size_t nbytes)
{
        /* Allocate a new stack node. */
        struct stack_block *sp;
        size_t const blocksize = nbytes <= MINSIZE
                               ? offsetof(struct stack_block, space) + MINSIZE
                               : K_ALIGN_Z(nbytes + offsetof(struct stack_block, space), 1024);

        INTOFF;
        sp = ckmalloc(psh, blocksize);
        sp->prev = pst->top;
        pst->fragmentation += pst->avail;
        pst->topsize        = blocksize - offsetof(struct stack_block, space);
        pst->avail          = blocksize - offsetof(struct stack_block, space);
        pst->nextbyte       = sp->space;
        pst->top            = sp;
        pst->blocks        += 1;
        INTON;
}

/**
 * Tries to grow the current stack block to hold a minimum of @a nbytes,
 * will allocate a new block and copy over pending string bytes if that's not
 * possible.
 */
static void pstgrowblock(shinstance *psh, pstack_block *pst, size_t nbytes, size_t tocopy)
{
        struct stack_block *top = pst->top;
        size_t blocksize;

        assert(pst->avail < nbytes); /* only called when we need more space */
        assert(tocopy <= pst->avail);

        /* Double the size used thus far and add some fudge and alignment.  Make
           sure to at least allocate MINSIZE. */
        blocksize = K_MAX(K_ALIGN_Z(pst->avail * 2 + 100 + offsetof(struct stack_block, space), 64), MINSIZE);

        /* If that isn't sufficient, do request size w/ some fudge and alignment. */
        if (blocksize < nbytes + offsetof(struct stack_block, space))
            blocksize = K_ALIGN_Z(nbytes + offsetof(struct stack_block, space) + 100, 1024);

        /*
         * Reallocate the current stack node if we can.
         */
        if (   pst->nextbyte == &top->space[0] /* can't have anything else in the block */
            && top->prev != NULL /* first block is embedded in pst and cannot be reallocated */ ) {
                top = (struct stack_block *)ckrealloc(psh, top, blocksize);
                pst->top      = top;
                pst->topsize  = blocksize - offsetof(struct stack_block, space);
                pst->avail    = blocksize - offsetof(struct stack_block, space);
                pst->nextbyte = top->space;
        }
        /*
         * Otherwise allocate a new node and copy over the avail bytes
         * from the old one.
         */
        else {
                char const * const copysrc = pst->nextbyte;
                pstallocnewblock(psh, pst, nbytes);
                assert(pst->avail >= nbytes);
                assert(pst->avail >= tocopy);
                memcpy(pst->nextbyte, copysrc, tocopy);
        }
}

K_INLINE void *pstallocint(shinstance *psh, pstack_block *pst, size_t nbytes)
{
        void *ret;

        /*
         * Align the size and make sure we've got sufficient bytes available:
         */
        nbytes = SHELL_ALIGN(nbytes);
        if (pst->avail >= nbytes && (ssize_t)pst->avail >= 0) { /* likely*/ }
        else pstallocnewblock(psh, pst, nbytes);

        /*
         * Carve out the return block.
         */
        ret = pst->nextbyte;
        pst->nextbyte     += nbytes;
        pst->avail        -= nbytes;
        pst->bytesalloced += nbytes;
        pst->allocations  += 1;
        return ret;
}

#endif KASH_SEPARATE_PARSER_ALLOCATOR


void *pstalloc(struct shinstance *psh, size_t nbytes)
{
#ifdef KASH_SEPARATE_PARSER_ALLOCATOR
        return pstallocint(psh, psh->curpstack, nbytes);
#else
        return stalloc(psh, nbytes);
#endif
}

union node *pstallocnode(struct shinstance *psh, size_t nbytes)
{
#ifdef KASH_SEPARATE_PARSER_ALLOCATOR
        pstack_block * const pst = psh->curpstack;
        union node * const ret = (union node *)pstallocint(psh, pst, nbytes);
        pst->nodesalloced++;
        ret->pblock = pst;
        return ret;
#else
        return (union node *)pstalloc(psh, nbytes);
#endif
}

struct nodelist *pstalloclist(struct shinstance *psh)
{
#ifdef KASH_SEPARATE_PARSER_ALLOCATOR
        pstack_block *pst = psh->curpstack;
        pst->entriesalloced++;
        return (struct nodelist *)pstallocint(psh, pst, sizeof(struct nodelist));
#endif
        return (struct nodelist *)pstalloc(psh, sizeof(struct nodelist));
}

char *pstsavestr(struct shinstance *psh, const char *str)
{
        if (str) {
                size_t const nbytes = strlen(str) + 1;
#ifdef KASH_SEPARATE_PARSER_ALLOCATOR
                pstack_block *pst = psh->curpstack;
                pst->strbytesalloced += SHELL_ALIGN(nbytes);
                return (char *)memcpy(pstallocint(psh, pst, nbytes), str, nbytes);
#else
                return (char *)memcpy(pstalloc(psh, nbytes), str, nbytes);
#endif
        }
        return NULL;
}

char *pstmakestrspace(struct shinstance *psh, size_t minbytes, char *end)
{
#ifdef KASH_SEPARATE_PARSER_ALLOCATOR
        pstack_block *pst = psh->curpstack;
        size_t const len = end - pst->nextbyte;

        assert(pst->avail - pst->strleft == len);
        TRACE2((psh, "pstmakestrspace: len=%u minbytes=%u (=> %u)\n", len, minbytes, len + minbytes));

        pstgrowblock(psh, pst, minbytes + len, len);

        pst->strleft = pst->avail - len;
        return pst->nextbyte + len;

#else
        size_t const len = end - stackblock(psh);

        assert(stackblocksize(psh) - psh->sstrnleft == len);
        TRACE2((psh, "pstmakestrspace: len=%u minbytes=%u (=> %u)\n", len, minbytes, len + minbytes));

        minbytes += len;
        while (stackblocksize(psh) < minbytes)
                growstackblock(psh);

        psh->sstrnleft = (int)(stackblocksize(psh) - len);
        return (char *)stackblock(psh) + len;
#endif
}

/* PSTPUTC helper */
char *pstputcgrow(shinstance *psh, char *end, char c)
{
#ifdef KASH_SEPARATE_PARSER_ALLOCATOR
        pstack_block *pst = psh->curpstack;
        pst->strleft++;         /* PSTPUTC() already incremented it. */
        end = pstmakestrspace(psh, 1, end);
        assert(pst->strleft > 0);
        pst->strleft--;
#else
        psh->sstrnleft++;       /* PSTPUTC() already incremented it. */
        end = pstmakestrspace(psh, 1, end);
        assert(psh->sstrnleft > 0);
        psh->sstrnleft--;
#endif
        *end++ = c;
        return end;
}


char *pstgrabstr(struct shinstance *psh, char *end)
{
#ifdef KASH_SEPARATE_PARSER_ALLOCATOR
        pstack_block *pst = psh->curpstack;
        char * const pstart = pst->nextbyte;
        size_t nbytes = (size_t)(end - pstart);

        assert((uintptr_t)end > (uintptr_t)pstart);
        assert(end[-1] == '\0');
        assert(SHELL_ALIGN((uintptr_t)pstart) == (uintptr_t)pstart);
        assert(pst->avail - pst->strleft >= nbytes);

        nbytes = SHELL_ALIGN(nbytes); /** @todo don't align strings, align the other allocations. */
        pst->nextbyte += nbytes;
        pst->avail    -= nbytes;
        pst->strbytesalloced += nbytes;

        return pstart;

#else
        char * const pstart = stackblock(psh);
        size_t nbytes = (size_t)(end - pstart);

        assert((uintptr_t)end > (uintptr_t)pstart);
        assert(end[-1] == '\0');
        assert(SHELL_ALIGN((uintptr_t)pstart) == (uintptr_t)pstart);
        assert(stackblocksize(psh) - psh->sstrnleft >= nbytes);

        nbytes = SHELL_ALIGN(nbytes); /** @todo don't align strings, align the other allocations. */
        psh->stacknxt += nbytes;
        psh->stacknleft -= (int)nbytes;

        return pstart;
#endif
}