8a16b7a18f
Mainly focus on files that use BSD 3-Clause license. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. Special thanks to Wind River for providing access to "The Duke of Highlander" tool: an older (2014) run over FreeBSD tree was useful as a starting point.
493 lines
13 KiB
C
493 lines
13 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1983 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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#if defined(LIBC_SCCS) && !defined(lint)
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/*static char *sccsid = "from: @(#)malloc.c 5.11 (Berkeley) 2/23/91";*/
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static char *rcsid = "$FreeBSD$";
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#endif /* LIBC_SCCS and not lint */
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/*
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* malloc.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-10) bytes long.
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* This is designed for use in a virtual memory environment.
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*/
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#include <sys/types.h>
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#include <sys/sysctl.h>
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#include <stdarg.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/param.h>
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#include <sys/mman.h>
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#include "rtld_printf.h"
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static void morecore();
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static int findbucket();
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/*
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* Pre-allocate mmap'ed pages
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*/
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#define NPOOLPAGES (128*1024/pagesz)
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static caddr_t pagepool_start, pagepool_end;
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static int morepages();
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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 then a second word holds the size of the
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* requested block, less 1, rounded up to a multiple of sizeof(RMAGIC).
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* The order of elements is critical: ov_magic must overlay the low order
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* bits of ov_next, and ov_magic can not be a valid ov_next bit pattern.
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*/
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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_rmagic; /* range magic number */
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u_int ovu_size; /* actual block size */
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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_rmagic ovu.ovu_rmagic
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#define ov_size ovu.ovu_size
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};
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#define MAGIC 0xef /* magic # on accounting info */
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#define RMAGIC 0x5555 /* magic # on range info */
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#ifdef RCHECK
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#define RSLOP sizeof (u_short)
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#else
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#define RSLOP 0
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#endif
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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 30
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static union overhead *nextf[NBUCKETS];
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static int pagesz; /* page size */
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static int pagebucket; /* page size bucket */
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#ifdef MSTATS
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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];
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#include <stdio.h>
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#endif
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#if defined(MALLOC_DEBUG) || defined(RCHECK)
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#define ASSERT(p) if (!(p)) botch("p")
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#include <stdio.h>
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static void
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botch(s)
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char *s;
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{
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fprintf(stderr, "\r\nassertion botched: %s\r\n", s);
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(void) fflush(stderr); /* just in case user buffered it */
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abort();
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}
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#else
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#define ASSERT(p)
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#endif
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/* Debugging stuff */
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#define TRACE() rtld_printf("TRACE %s:%d\n", __FILE__, __LINE__)
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/*
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* The array of supported page sizes is provided by the user, i.e., the
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* program that calls this storage allocator. That program must initialize
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* the array before making its first call to allocate storage. The array
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* must contain at least one page size. The page sizes must be stored in
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* increasing order.
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*/
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extern size_t *pagesizes;
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void *
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malloc(nbytes)
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size_t nbytes;
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{
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register union overhead *op;
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register int bucket;
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register long n;
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register unsigned amt;
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/*
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* First time malloc is called, setup page size and
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* align break pointer so all data will be page aligned.
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*/
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if (pagesz == 0) {
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pagesz = n = pagesizes[0];
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if (morepages(NPOOLPAGES) == 0)
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return NULL;
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op = (union overhead *)(pagepool_start);
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n = n - sizeof (*op) - ((long)op & (n - 1));
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if (n < 0)
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n += pagesz;
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if (n) {
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pagepool_start += n;
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}
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bucket = 0;
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amt = 8;
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while ((unsigned)pagesz > amt) {
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amt <<= 1;
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bucket++;
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}
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pagebucket = bucket;
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}
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/*
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* Convert amount of memory requested into closest block size
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* stored in hash buckets which satisfies request.
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* Account for space used per block for accounting.
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*/
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if (nbytes <= (unsigned long)(n = pagesz - sizeof (*op) - RSLOP)) {
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#ifndef RCHECK
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amt = 8; /* size of first bucket */
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bucket = 0;
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#else
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amt = 16; /* size of first bucket */
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bucket = 1;
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#endif
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n = -(sizeof (*op) + RSLOP);
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} else {
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amt = pagesz;
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bucket = pagebucket;
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}
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while (nbytes > amt + n) {
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amt <<= 1;
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if (amt == 0)
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return (NULL);
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bucket++;
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}
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/*
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* If nothing in hash bucket right now,
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* request more memory from the system.
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*/
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if ((op = nextf[bucket]) == NULL) {
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morecore(bucket);
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if ((op = nextf[bucket]) == NULL)
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return (NULL);
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}
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/* remove from linked list */
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nextf[bucket] = op->ov_next;
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op->ov_magic = MAGIC;
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op->ov_index = bucket;
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#ifdef MSTATS
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nmalloc[bucket]++;
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#endif
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#ifdef RCHECK
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/*
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* Record allocated size of block and
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* bound space with magic numbers.
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*/
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op->ov_size = roundup2(nbytes, RSLOP);
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op->ov_rmagic = RMAGIC;
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*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
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#endif
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return ((char *)(op + 1));
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}
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void *
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calloc(size_t num, size_t size)
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{
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void *ret;
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if (size != 0 && (num * size) / size != num) {
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/* size_t overflow. */
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return (NULL);
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}
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if ((ret = malloc(num * size)) != NULL)
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memset(ret, 0, num * size);
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return (ret);
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}
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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(bucket)
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int bucket;
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{
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register union overhead *op;
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register int sz; /* size of desired block */
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int amt; /* amount to allocate */
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int nblks; /* how many blocks we get */
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/*
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* sbrk_size <= 0 only for big, FLUFFY, requests (about
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* 2^30 bytes on a VAX, I think) or for a negative arg.
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*/
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sz = 1 << (bucket + 3);
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#ifdef MALLOC_DEBUG
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ASSERT(sz > 0);
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#else
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if (sz <= 0)
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return;
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#endif
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if (sz < pagesz) {
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amt = pagesz;
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nblks = amt / sz;
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} else {
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amt = sz + pagesz;
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nblks = 1;
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}
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if (amt > pagepool_end - pagepool_start)
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if (morepages(amt/pagesz + NPOOLPAGES) == 0)
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return;
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op = (union overhead *)pagepool_start;
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pagepool_start += amt;
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/*
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* Add new memory allocated to that on
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* free list for this hash bucket.
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*/
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nextf[bucket] = op;
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while (--nblks > 0) {
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op->ov_next = (union overhead *)((caddr_t)op + sz);
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op = (union overhead *)((caddr_t)op + sz);
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}
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}
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void
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free(cp)
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void *cp;
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{
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register int size;
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register union overhead *op;
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if (cp == NULL)
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return;
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op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
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#ifdef MALLOC_DEBUG
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ASSERT(op->ov_magic == MAGIC); /* make sure it was in use */
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#else
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if (op->ov_magic != MAGIC)
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return; /* sanity */
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#endif
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#ifdef RCHECK
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ASSERT(op->ov_rmagic == RMAGIC);
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ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
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#endif
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size = op->ov_index;
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ASSERT(size < NBUCKETS);
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op->ov_next = nextf[size]; /* also clobbers ov_magic */
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nextf[size] = op;
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#ifdef MSTATS
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nmalloc[size]--;
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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 through 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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int realloc_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */
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void *
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realloc(cp, nbytes)
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void *cp;
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size_t nbytes;
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{
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register u_int onb;
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register int i;
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union overhead *op;
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char *res;
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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 - 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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} 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
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* free list. First, check the most common
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* case (last element free'd), then (this failing)
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* the last ``realloc_srchlen'' items free'd.
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* If all lookups fail, then assume the size of
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* the memory block being realloc'd is the
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* largest possible (so that all "nbytes" of new
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* memory are copied into). Note that this could cause
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* a memory fault if the old area was tiny, and the moon
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* is gibbous. However, that is very unlikely.
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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 = NBUCKETS;
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}
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onb = 1 << (i + 3);
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if (onb < (u_int)pagesz)
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onb -= sizeof (*op) + RSLOP;
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else
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onb += pagesz - sizeof (*op) - RSLOP;
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/* avoid the copy if same size block */
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if (was_alloced) {
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if (i) {
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i = 1 << (i + 2);
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if (i < pagesz)
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i -= sizeof (*op) + RSLOP;
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else
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i += pagesz - sizeof (*op) - RSLOP;
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}
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if (nbytes <= onb && nbytes > (size_t)i) {
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#ifdef RCHECK
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op->ov_size = roundup2(nbytes, RSLOP);
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*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
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#endif
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return(cp);
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} else
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free(cp);
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}
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if ((res = malloc(nbytes)) == NULL)
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return (NULL);
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if (cp != res) /* common optimization if "compacting" */
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bcopy(cp, res, (nbytes < onb) ? nbytes : onb);
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return (res);
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}
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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(freep, srchlen)
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union overhead *freep;
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int srchlen;
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{
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register union overhead *p;
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register int i, 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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#ifdef MSTATS
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/*
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* mstats - print out statistics about malloc
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*
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* Prints two lines of numbers, one showing the length of the free list
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* for each size category, the second showing the number of mallocs -
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* frees for each size category.
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*/
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mstats(s)
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char *s;
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{
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register int i, j;
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register union overhead *p;
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int totfree = 0,
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totused = 0;
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fprintf(stderr, "Memory allocation statistics %s\nfree:\t", s);
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for (i = 0; i < NBUCKETS; i++) {
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for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
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;
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fprintf(stderr, " %d", j);
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totfree += j * (1 << (i + 3));
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}
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fprintf(stderr, "\nused:\t");
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for (i = 0; i < NBUCKETS; i++) {
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fprintf(stderr, " %d", nmalloc[i]);
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totused += nmalloc[i] * (1 << (i + 3));
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}
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fprintf(stderr, "\n\tTotal in use: %d, total free: %d\n",
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totused, totfree);
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}
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#endif
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static int
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morepages(n)
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int n;
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{
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int fd = -1;
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int offset;
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if (pagepool_end - pagepool_start > pagesz) {
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caddr_t addr = (caddr_t)
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(((long)pagepool_start + pagesz - 1) & ~(pagesz - 1));
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if (munmap(addr, pagepool_end - addr) != 0)
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rtld_fdprintf(STDERR_FILENO, "morepages: munmap %p",
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addr);
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}
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offset = (long)pagepool_start - ((long)pagepool_start & ~(pagesz - 1));
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if ((pagepool_start = mmap(0, n * pagesz,
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PROT_READ|PROT_WRITE,
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MAP_ANON|MAP_PRIVATE, fd, 0)) == (caddr_t)-1) {
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rtld_printf("Cannot map anonymous memory\n");
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return 0;
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}
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pagepool_end = pagepool_start + n * pagesz;
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pagepool_start += offset;
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return n;
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}
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