minix/libexec/ld.elf_so/xmalloc.c

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/* $NetBSD: xmalloc.c,v 1.11 2011/05/25 14:41:46 christos Exp $ */
/*
* Copyright 1996 John D. Polstra.
* Copyright 1996 Matt Thomas <matt@3am-software.com>
* All rights reserved.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Polstra.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.
*
* 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.
*/
#ifdef __minix
/* Minix mmap can do this. */
#define mmap minix_mmap
#define munmap minix_munmap
#endif
#if defined(LIBC_SCCS) && !defined(lint)
/*static char *sccsid = "from: @(#)malloc.c 5.11 (Berkeley) 2/23/91";*/
#endif /* LIBC_SCCS and not lint */
/*
* malloc.c (Caltech) 2/21/82
* Chris Kingsley, kingsley@cit-20.
*
* This is a very fast storage allocator. It allocates blocks of a small
* number of different sizes, and keeps free lists of each size. Blocks that
* don't exactly fit are passed up to the next larger size. In this
* implementation, the available sizes are 2^n-4 (or 2^n-10) bytes long.
* This is designed for use in a virtual memory environment.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: xmalloc.c,v 1.11 2011/05/25 14:41:46 christos Exp $");
#endif /* not lint */
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include "rtld.h"
/*
* Pre-allocate mmap'ed pages
*/
#define NPOOLPAGES (32*1024/pagesz)
static char *pagepool_start, *pagepool_end;
static int morepages(int);
#define PAGEPOOL_SIZE (size_t)(pagepool_end - pagepool_start)
/*
* The overhead on a block is at least 4 bytes. When free, this space
* contains a pointer to the next free block, and the bottom two bits must
* be zero. When in use, the first byte is set to MAGIC, and the second
* byte is the size index. The remaining bytes are for alignment.
* If range checking is enabled then a second word holds the size of the
* requested block, less 1, rounded up to a multiple of sizeof(RMAGIC).
* The order of elements is critical: ov_magic must overlay the low order
* bits of ov_next, and ov_magic can not be a valid ov_next bit pattern.
*/
union overhead {
union overhead *ov_next; /* when free */
struct {
u_char ovu_magic; /* magic number */
u_char ovu_index; /* bucket # */
#ifdef RCHECK
u_short ovu_rmagic; /* range magic number */
u_int ovu_size; /* actual block size */
#endif
} ovu;
#define ov_magic ovu.ovu_magic
#define ov_index ovu.ovu_index
#define ov_rmagic ovu.ovu_rmagic
#define ov_size ovu.ovu_size
};
static void morecore(size_t);
static void *imalloc(size_t);
#define MAGIC 0xef /* magic # on accounting info */
#define RMAGIC 0x5555 /* magic # on range info */
#ifdef RCHECK
#define RSLOP (sizeof (u_short))
#else
#define RSLOP 0
#endif
/*
* nextf[i] is the pointer to the next free block of size 2^(i+3). The
* smallest allocatable block is 8 bytes. The overhead information
* precedes the data area returned to the user.
*/
#define NBUCKETS 30
static union overhead *nextf[NBUCKETS];
static size_t pagesz; /* page size */
static size_t pagebucket; /* page size bucket */
static size_t pageshift; /* page size shift */
#ifdef MSTATS
/*
* nmalloc[i] is the difference between the number of mallocs and frees
* for a given block size.
*/
static u_int nmalloc[NBUCKETS];
#endif
#if defined(MALLOC_DEBUG) || defined(RCHECK)
#define ASSERT(p) if (!(p)) botch("p")
static void
botch(const char *s)
{
xwarnx("\r\nassertion botched: %s\r\n", s);
abort();
}
#else
#define ASSERT(p)
#endif
#define TRACE() xprintf("TRACE %s:%d\n", __FILE__, __LINE__)
static void *
imalloc(size_t nbytes)
{
union overhead *op;
size_t bucket;
size_t n, m;
unsigned amt;
/*
* First time malloc is called, setup page size and
* align break pointer so all data will be page aligned.
*/
if (pagesz == 0) {
pagesz = n = _rtld_pagesz;
if (morepages(NPOOLPAGES) == 0)
return NULL;
op = (union overhead *)(pagepool_start);
m = sizeof (*op) - (((char *)op - (char *)NULL) & (n - 1));
if (n < m)
n += pagesz - m;
else
n -= m;
if (n) {
pagepool_start += n;
}
bucket = 0;
amt = sizeof(union overhead);
while (pagesz > amt) {
amt <<= 1;
bucket++;
}
pagebucket = bucket;
pageshift = ffs(pagesz) - 1;
}
/*
* Convert amount of memory requested into closest block size
* stored in hash buckets which satisfies request.
* Account for space used per block for accounting.
*/
if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) {
if (sizeof(union overhead) & (sizeof(union overhead) - 1)) {
amt = sizeof(union overhead) * 2;
bucket = 1;
} else {
amt = sizeof(union overhead); /* size of first bucket */
bucket = 0;
}
n = -(sizeof (*op) + RSLOP);
} else {
amt = pagesz;
bucket = pagebucket;
}
while (nbytes > amt + n) {
amt <<= 1;
if (amt == 0)
return (NULL);
bucket++;
}
/*
* If nothing in hash bucket right now,
* request more memory from the system.
*/
if ((op = nextf[bucket]) == NULL) {
morecore(bucket);
if ((op = nextf[bucket]) == NULL)
return (NULL);
}
/* remove from linked list */
nextf[bucket] = op->ov_next;
op->ov_magic = MAGIC;
op->ov_index = bucket;
#ifdef MSTATS
nmalloc[bucket]++;
#endif
#ifdef RCHECK
/*
* Record allocated size of block and
* bound space with magic numbers.
*/
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
op->ov_rmagic = RMAGIC;
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
#endif
return ((char *)(op + 1));
}
/*
* Allocate more memory to the indicated bucket.
*/
static void
morecore(size_t bucket)
{
union overhead *op;
size_t sz; /* size of desired block */
size_t amt; /* amount to allocate */
size_t nblks; /* how many blocks we get */
/*
* sbrk_size <= 0 only for big, FLUFFY, requests (about
* 2^30 bytes on a VAX, I think) or for a negative arg.
*/
sz = 1 << (bucket + 3);
#ifdef MALLOC_DEBUG
ASSERT(sz > 0);
#endif
if (sz < pagesz) {
amt = pagesz;
nblks = amt >> (bucket + 3);
} else {
amt = sz + pagesz;
nblks = 1;
}
if (amt > PAGEPOOL_SIZE)
if (morepages((amt >> pageshift) + NPOOLPAGES) == 0)
return;
op = (union overhead *)pagepool_start;
pagepool_start += amt;
/*
* Add new memory allocated to that on
* free list for this hash bucket.
*/
nextf[bucket] = op;
while (--nblks > 0) {
op->ov_next = (union overhead *)((caddr_t)op + sz);
op = (union overhead *)((caddr_t)op + sz);
}
}
void
xfree(void *cp)
{
int size;
union overhead *op;
if (cp == NULL)
return;
op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
#ifdef MALLOC_DEBUG
ASSERT(op->ov_magic == MAGIC); /* make sure it was in use */
#else
if (op->ov_magic != MAGIC)
return; /* sanity */
#endif
#ifdef RCHECK
ASSERT(op->ov_rmagic == RMAGIC);
ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
#endif
size = op->ov_index;
ASSERT(size < NBUCKETS);
op->ov_next = nextf[size]; /* also clobbers ov_magic */
nextf[size] = op;
#ifdef MSTATS
nmalloc[size]--;
#endif
}
static void *
irealloc(void *cp, size_t nbytes)
{
size_t onb;
size_t i;
union overhead *op;
char *res;
if (cp == NULL)
return (imalloc(nbytes));
op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
if (op->ov_magic != MAGIC) {
static const char *err_str =
"memory corruption or double free in realloc\n";
extern char *__progname;
write(STDERR_FILENO, __progname, strlen(__progname));
write(STDERR_FILENO, err_str, strlen(err_str));
abort();
}
i = op->ov_index;
onb = 1 << (i + 3);
if (onb < pagesz)
onb -= sizeof (*op) + RSLOP;
else
onb += pagesz - sizeof (*op) - RSLOP;
/* avoid the copy if same size block */
if (i) {
i = 1 << (i + 2);
if (i < pagesz)
i -= sizeof (*op) + RSLOP;
else
i += pagesz - sizeof (*op) - RSLOP;
}
if (nbytes <= onb && nbytes > i) {
#ifdef RCHECK
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
#endif
return(cp);
} else
xfree(cp);
if ((res = imalloc(nbytes)) == NULL)
return (NULL);
if (cp != res) /* common optimization if "compacting" */
memcpy(res, cp, (nbytes < onb) ? nbytes : onb);
return (res);
}
#ifdef MSTATS
/*
* 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.
*/
void
mstats(char *s)
{
int i, j;
union overhead *p;
int totfree = 0,
totused = 0;
xprintf("Memory allocation statistics %s\nfree:\t", s);
for (i = 0; i < NBUCKETS; i++) {
for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
;
xprintf(" %d", j);
totfree += j * (1 << (i + 3));
}
xprintf("\nused:\t");
for (i = 0; i < NBUCKETS; i++) {
xprintf(" %d", nmalloc[i]);
totused += nmalloc[i] * (1 << (i + 3));
}
xprintf("\n\tTotal in use: %d, total free: %d\n",
totused, totfree);
}
#endif
static int
morepages(int n)
{
int fd = -1;
int offset;
#ifdef NEED_DEV_ZERO
fd = open("/dev/zero", O_RDWR, 0);
if (fd == -1)
xerr(1, "/dev/zero");
#endif
if (PAGEPOOL_SIZE > pagesz) {
caddr_t addr = (caddr_t)
(((long)pagepool_start + pagesz - 1) & ~(pagesz - 1));
if (munmap(addr, pagepool_end - addr) != 0)
xwarn("morepages: munmap %p", addr);
}
offset = (long)pagepool_start - ((long)pagepool_start & ~(pagesz - 1));
if ((pagepool_start = mmap(0, n * pagesz,
PROT_READ|PROT_WRITE,
MAP_ANON|MAP_PRIVATE, fd, 0)) == (caddr_t)-1) {
xprintf("Cannot map anonymous memory");
return 0;
}
pagepool_end = pagepool_start + n * pagesz;
pagepool_start += offset;
#ifdef NEED_DEV_ZERO
close(fd);
#endif
return n;
}
void *
xcalloc(size_t size)
{
return memset(xmalloc(size), 0, size);
}
void *
xmalloc(size_t size)
{
void *p = imalloc(size);
if (p == NULL)
xerr(1, "%s", xstrerror(errno));
return p;
}
void *
xrealloc(void *p, size_t size)
{
p = irealloc(p, size);
if (p == NULL)
xerr(1, "%s", xstrerror(errno));
return p;
}
char *
xstrdup(const char *str)
{
size_t len;
char *copy;
len = strlen(str) + 1;
copy = xmalloc(len);
memcpy(copy, str, len);
return (copy);
}