612 lines
16 KiB
C
612 lines
16 KiB
C
/* $Header: /p/tcsh/cvsroot/tcsh/tc.alloc.c,v 3.46 2006/03/02 18:46:44 christos Exp $ */
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/*
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* tc.alloc.c (Caltech) 2/21/82
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* Chris Kingsley, kingsley@cit-20.
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*
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* This is a very fast storage allocator. It allocates blocks of a small
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* number of different sizes, and keeps free lists of each size. Blocks that
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* don't exactly fit are passed up to the next larger size. In this
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* implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
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* This is designed for use in a program that uses vast quantities of memory,
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* but bombs when it runs out.
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*/
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/*-
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* Copyright (c) 1980, 1991 The Regents of the University of California.
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* All rights reserved.
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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 "sh.h"
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RCSID("$tcsh: tc.alloc.c,v 3.46 2006/03/02 18:46:44 christos Exp $")
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#define RCHECK
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#define DEBUG
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static char *memtop = NULL; /* PWP: top of current memory */
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static char *membot = NULL; /* PWP: bottom of allocatable memory */
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int dont_free = 0;
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#ifdef WINNT_NATIVE
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# define malloc fmalloc
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# define free ffree
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# define calloc fcalloc
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# define realloc frealloc
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#endif /* WINNT_NATIVE */
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#if !defined(DEBUG) || defined(SYSMALLOC)
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static void
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out_of_memory (void)
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{
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static const char msg[] = "Out of memory\n";
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write(didfds ? 2 : SHDIAG, msg, strlen(msg));
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_exit(1);
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}
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#endif
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#ifndef SYSMALLOC
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#ifdef SX
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extern void* sbrk();
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#endif
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/*
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* Lots of os routines are busted and try to free invalid pointers.
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* Although our free routine is smart enough and it will pick bad
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* pointers most of the time, in cases where we know we are going to get
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* a bad pointer, we'd rather leak.
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*/
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#ifndef NULL
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#define NULL 0
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#endif
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typedef unsigned char U_char; /* we don't really have signed chars */
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typedef unsigned int U_int;
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typedef unsigned short U_short;
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typedef unsigned long U_long;
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/*
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* The overhead on a block is at least 4 bytes. When free, this space
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* contains a pointer to the next free block, and the bottom two bits must
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* be zero. When in use, the first byte is set to MAGIC, and the second
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* byte is the size index. The remaining bytes are for alignment.
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* If range checking is enabled and the size of the block fits
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* in two bytes, then the top two bytes hold the size of the requested block
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* plus the range checking words, and the header word MINUS ONE.
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*/
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#define MEMALIGN(a) (((a) + ROUNDUP) & ~ROUNDUP)
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union overhead {
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union overhead *ov_next; /* when free */
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struct {
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U_char ovu_magic; /* magic number */
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U_char ovu_index; /* bucket # */
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#ifdef RCHECK
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U_short ovu_size; /* actual block size */
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U_int ovu_rmagic; /* range magic number */
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#endif
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} ovu;
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#define ov_magic ovu.ovu_magic
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#define ov_index ovu.ovu_index
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#define ov_size ovu.ovu_size
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#define ov_rmagic ovu.ovu_rmagic
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};
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#define MAGIC 0xfd /* magic # on accounting info */
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#define RMAGIC 0x55555555 /* magic # on range info */
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#ifdef RCHECK
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#define RSLOP sizeof (U_int)
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#else
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#define RSLOP 0
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#endif
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#define ROUNDUP 7
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/*
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* nextf[i] is the pointer to the next free block of size 2^(i+3). The
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* smallest allocatable block is 8 bytes. The overhead information
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* precedes the data area returned to the user.
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*/
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#define NBUCKETS ((sizeof(long) << 3) - 3)
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static union overhead *nextf[NBUCKETS] IZERO_STRUCT;
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/*
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* nmalloc[i] is the difference between the number of mallocs and frees
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* for a given block size.
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*/
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static U_int nmalloc[NBUCKETS] IZERO_STRUCT;
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#ifndef lint
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static int findbucket (union overhead *, int);
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static void morecore (int);
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#endif
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#ifdef DEBUG
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# define CHECK(a, str, p) \
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if (a) { \
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xprintf(str, p); \
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xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \
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abort(); \
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}
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#else
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# define CHECK(a, str, p) \
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if (a) { \
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xprintf(str, p); \
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xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \
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return; \
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}
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#endif
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memalign_t
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malloc(size_t nbytes)
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{
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#ifndef lint
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union overhead *p;
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int bucket = 0;
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unsigned shiftr;
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/*
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* Convert amount of memory requested into closest block size stored in
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* hash buckets which satisfies request. Account for space used per block
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* for accounting.
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*/
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#ifdef SUNOS4
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/*
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* SunOS localtime() overwrites the 9th byte on an 8 byte malloc()....
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* so we get one more...
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* From Michael Schroeder: This is not true. It depends on the
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* timezone string. In Europe it can overwrite the 13th byte on a
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* 12 byte malloc.
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* So we punt and we always allocate an extra byte.
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*/
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nbytes++;
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#endif
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nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead)) + nbytes + RSLOP);
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shiftr = (nbytes - 1) >> 2;
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/* apart from this loop, this is O(1) */
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while ((shiftr >>= 1) != 0)
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bucket++;
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/*
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* If nothing in hash bucket right now, request more memory from the
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* system.
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*/
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if (nextf[bucket] == NULL)
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morecore(bucket);
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if ((p = nextf[bucket]) == NULL) {
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child++;
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#ifndef DEBUG
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out_of_memory();
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#else
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showall(NULL, NULL);
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xprintf(CGETS(19, 1, "nbytes=%zu: Out of memory\n"), nbytes);
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abort();
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#endif
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/* fool lint */
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return ((memalign_t) 0);
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}
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/* remove from linked list */
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nextf[bucket] = nextf[bucket]->ov_next;
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p->ov_magic = MAGIC;
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p->ov_index = bucket;
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nmalloc[bucket]++;
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#ifdef RCHECK
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/*
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* Record allocated size of block and bound space with magic numbers.
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*/
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p->ov_size = (p->ov_index <= 13) ? nbytes - 1 : 0;
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p->ov_rmagic = RMAGIC;
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*((U_int *) (((caddr_t) p) + nbytes - RSLOP)) = RMAGIC;
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#endif
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return ((memalign_t) (((caddr_t) p) + MEMALIGN(sizeof(union overhead))));
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#else
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if (nbytes)
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return ((memalign_t) 0);
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else
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return ((memalign_t) 0);
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#endif /* !lint */
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}
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#ifndef lint
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/*
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* Allocate more memory to the indicated bucket.
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*/
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static void
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morecore(int bucket)
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{
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union overhead *op;
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int rnu; /* 2^rnu bytes will be requested */
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int nblks; /* become nblks blocks of the desired size */
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int siz;
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if (nextf[bucket])
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return;
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/*
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* Insure memory is allocated on a page boundary. Should make getpageize
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* call?
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*/
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op = (union overhead *) sbrk(0);
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memtop = (char *) op;
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if (membot == NULL)
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membot = memtop;
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if ((long) op & 0x3ff) {
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memtop = sbrk((int) (1024 - ((long) op & 0x3ff)));
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memtop += (long) (1024 - ((long) op & 0x3ff));
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}
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/* take 2k unless the block is bigger than that */
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rnu = (bucket <= 8) ? 11 : bucket + 3;
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nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */
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memtop = sbrk(1 << rnu); /* PWP */
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op = (union overhead *) memtop;
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/* no more room! */
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if ((long) op == -1)
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return;
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memtop += (long) (1 << rnu);
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/*
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* Round up to minimum allocation size boundary and deduct from block count
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* to reflect.
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*/
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if (((U_long) op) & ROUNDUP) {
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op = (union overhead *) (((U_long) op + (ROUNDUP + 1)) & ~ROUNDUP);
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nblks--;
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}
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/*
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* Add new memory allocated to that on free list for this hash bucket.
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*/
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nextf[bucket] = op;
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siz = 1 << (bucket + 3);
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while (--nblks > 0) {
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op->ov_next = (union overhead *) (((caddr_t) op) + siz);
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op = (union overhead *) (((caddr_t) op) + siz);
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}
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op->ov_next = NULL;
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}
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#endif
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void
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free(ptr_t cp)
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{
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#ifndef lint
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int size;
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union overhead *op;
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/*
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* the don't free flag is there so that we avoid os bugs in routines
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* that free invalid pointers!
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*/
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if (cp == NULL || dont_free)
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return;
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CHECK(!memtop || !membot,
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CGETS(19, 2, "free(%p) called before any allocations."), cp);
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CHECK(cp > (ptr_t) memtop,
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CGETS(19, 3, "free(%p) above top of memory."), cp);
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CHECK(cp < (ptr_t) membot,
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CGETS(19, 4, "free(%p) below bottom of memory."), cp);
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op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead)));
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CHECK(op->ov_magic != MAGIC,
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CGETS(19, 5, "free(%p) bad block."), cp);
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#ifdef RCHECK
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if (op->ov_index <= 13)
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CHECK(*(U_int *) ((caddr_t) op + op->ov_size + 1 - RSLOP) != RMAGIC,
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CGETS(19, 6, "free(%p) bad range check."), cp);
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#endif
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CHECK(op->ov_index >= NBUCKETS,
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CGETS(19, 7, "free(%p) bad block index."), cp);
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size = op->ov_index;
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op->ov_next = nextf[size];
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nextf[size] = op;
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nmalloc[size]--;
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#else
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if (cp == NULL)
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return;
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#endif
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}
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memalign_t
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calloc(size_t i, size_t j)
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{
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#ifndef lint
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char *cp;
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i *= j;
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cp = xmalloc(i);
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memset(cp, 0, i);
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return ((memalign_t) cp);
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#else
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if (i && j)
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return ((memalign_t) 0);
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else
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return ((memalign_t) 0);
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#endif
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}
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/*
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* When a program attempts "storage compaction" as mentioned in the
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* old malloc man page, it realloc's an already freed block. Usually
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* this is the last block it freed; occasionally it might be farther
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* back. We have to search all the free lists for the block in order
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* to determine its bucket: 1st we make one pass thru the lists
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* checking only the first block in each; if that fails we search
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* ``realloc_srchlen'' blocks in each list for a match (the variable
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* is extern so the caller can modify it). If that fails we just copy
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* however many bytes was given to realloc() and hope it's not huge.
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*/
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#ifndef lint
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/* 4 should be plenty, -1 =>'s whole list */
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static int realloc_srchlen = 4;
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#endif /* lint */
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memalign_t
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realloc(ptr_t cp, size_t nbytes)
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{
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#ifndef lint
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U_int onb;
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union overhead *op;
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ptr_t res;
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int i;
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int was_alloced = 0;
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if (cp == NULL)
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return (malloc(nbytes));
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op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead)));
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if (op->ov_magic == MAGIC) {
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was_alloced++;
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i = op->ov_index;
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}
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else
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/*
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* Already free, doing "compaction".
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*
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* Search for the old block of memory on the free list. First, check the
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* most common case (last element free'd), then (this failing) the last
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* ``realloc_srchlen'' items free'd. If all lookups fail, then assume
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* the size of the memory block being realloc'd is the smallest
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* possible.
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*/
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if ((i = findbucket(op, 1)) < 0 &&
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(i = findbucket(op, realloc_srchlen)) < 0)
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i = 0;
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onb = MEMALIGN(nbytes + MEMALIGN(sizeof(union overhead)) + RSLOP);
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/* avoid the copy if same size block */
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if (was_alloced && (onb <= (U_int) (1 << (i + 3))) &&
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(onb > (U_int) (1 << (i + 2)))) {
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#ifdef RCHECK
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/* JMR: formerly this wasn't updated ! */
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nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead))+nbytes+RSLOP);
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*((U_int *) (((caddr_t) op) + nbytes - RSLOP)) = RMAGIC;
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op->ov_rmagic = RMAGIC;
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op->ov_size = (op->ov_index <= 13) ? nbytes - 1 : 0;
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#endif
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return ((memalign_t) cp);
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}
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if ((res = malloc(nbytes)) == NULL)
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return ((memalign_t) NULL);
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if (cp != res) { /* common optimization */
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/*
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* christos: this used to copy nbytes! It should copy the
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* smaller of the old and new size
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*/
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onb = (1 << (i + 3)) - MEMALIGN(sizeof(union overhead)) - RSLOP;
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(void) memmove(res, cp, onb < nbytes ? onb : nbytes);
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}
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if (was_alloced)
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free(cp);
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return ((memalign_t) res);
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#else
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if (cp && nbytes)
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return ((memalign_t) 0);
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else
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return ((memalign_t) 0);
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#endif /* !lint */
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}
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#ifndef lint
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/*
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* Search ``srchlen'' elements of each free list for a block whose
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* header starts at ``freep''. If srchlen is -1 search the whole list.
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* Return bucket number, or -1 if not found.
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*/
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static int
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findbucket(union overhead *freep, int srchlen)
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{
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union overhead *p;
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size_t i;
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int j;
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for (i = 0; i < NBUCKETS; i++) {
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j = 0;
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for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
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if (p == freep)
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return (i);
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j++;
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}
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}
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return (-1);
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}
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#endif
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#else /* SYSMALLOC */
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/**
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** ``Protected versions'' of malloc, realloc, calloc, and free
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**
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** On many systems:
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**
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** 1. malloc(0) is bad
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** 2. free(0) is bad
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** 3. realloc(0, n) is bad
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** 4. realloc(n, 0) is bad
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**
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** Also we call our error routine if we run out of memory.
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**/
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memalign_t
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smalloc(size_t n)
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{
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ptr_t ptr;
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n = n ? n : 1;
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#ifdef HAVE_SBRK
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if (membot == NULL)
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membot = sbrk(0);
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#endif /* HAVE_SBRK */
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if ((ptr = malloc(n)) == NULL)
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out_of_memory();
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#ifndef HAVE_SBRK
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if (memtop < ((char *) ptr) + n)
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memtop = ((char *) ptr) + n;
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if (membot == NULL)
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membot = ptr;
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#endif /* !HAVE_SBRK */
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return ((memalign_t) ptr);
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}
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memalign_t
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srealloc(ptr_t p, size_t n)
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{
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ptr_t ptr;
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n = n ? n : 1;
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#ifdef HAVE_SBRK
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if (membot == NULL)
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membot = sbrk(0);
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#endif /* HAVE_SBRK */
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if ((ptr = (p ? realloc(p, n) : malloc(n))) == NULL)
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out_of_memory();
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#ifndef HAVE_SBRK
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if (memtop < ((char *) ptr) + n)
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memtop = ((char *) ptr) + n;
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if (membot == NULL)
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membot = ptr;
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#endif /* !HAVE_SBRK */
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return ((memalign_t) ptr);
|
|
}
|
|
|
|
memalign_t
|
|
scalloc(size_t s, size_t n)
|
|
{
|
|
ptr_t ptr;
|
|
|
|
n *= s;
|
|
n = n ? n : 1;
|
|
|
|
#ifdef HAVE_SBRK
|
|
if (membot == NULL)
|
|
membot = sbrk(0);
|
|
#endif /* HAVE_SBRK */
|
|
|
|
if ((ptr = malloc(n)) == NULL)
|
|
out_of_memory();
|
|
|
|
memset (ptr, 0, n);
|
|
|
|
#ifndef HAVE_SBRK
|
|
if (memtop < ((char *) ptr) + n)
|
|
memtop = ((char *) ptr) + n;
|
|
if (membot == NULL)
|
|
membot = ptr;
|
|
#endif /* !HAVE_SBRK */
|
|
|
|
return ((memalign_t) ptr);
|
|
}
|
|
|
|
void
|
|
sfree(ptr_t p)
|
|
{
|
|
if (p && !dont_free)
|
|
free(p);
|
|
}
|
|
|
|
#endif /* SYSMALLOC */
|
|
|
|
/*
|
|
* mstats - print out statistics about malloc
|
|
*
|
|
* Prints two lines of numbers, one showing the length of the free list
|
|
* for each size category, the second showing the number of mallocs -
|
|
* frees for each size category.
|
|
*/
|
|
/*ARGSUSED*/
|
|
void
|
|
showall(Char **v, struct command *c)
|
|
{
|
|
#ifndef SYSMALLOC
|
|
size_t i, j;
|
|
union overhead *p;
|
|
int totfree = 0, totused = 0;
|
|
|
|
xprintf(CGETS(19, 8, "%s current memory allocation:\nfree:\t"), progname);
|
|
for (i = 0; i < NBUCKETS; i++) {
|
|
for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
|
|
continue;
|
|
xprintf(" %4zd", j);
|
|
totfree += j * (1 << (i + 3));
|
|
}
|
|
xprintf(CGETS(19, 9, "\nused:\t"));
|
|
for (i = 0; i < NBUCKETS; i++) {
|
|
xprintf(" %4d", nmalloc[i]);
|
|
totused += nmalloc[i] * (1 << (i + 3));
|
|
}
|
|
xprintf(CGETS(19, 10, "\n\tTotal in use: %d, total free: %d\n"),
|
|
totused, totfree);
|
|
xprintf(CGETS(19, 11,
|
|
"\tAllocated memory from 0x%lx to 0x%lx. Real top at 0x%lx\n"),
|
|
(unsigned long) membot, (unsigned long) memtop,
|
|
(unsigned long) sbrk(0));
|
|
#else
|
|
#ifdef HAVE_SBRK
|
|
memtop = sbrk(0);
|
|
#endif /* HAVE_SBRK */
|
|
xprintf(CGETS(19, 12, "Allocated memory from 0x%lx to 0x%lx (%ld).\n"),
|
|
(unsigned long) membot, (unsigned long) memtop,
|
|
(unsigned long) (memtop - membot));
|
|
#endif /* SYSMALLOC */
|
|
USE(c);
|
|
USE(v);
|
|
}
|