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Diffstat (limited to 'gnu/usr.bin/ld/rtld/malloc.c')
| -rw-r--r-- | gnu/usr.bin/ld/rtld/malloc.c | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/gnu/usr.bin/ld/rtld/malloc.c b/gnu/usr.bin/ld/rtld/malloc.c new file mode 100644 index 000000000000..4a9e7e65e9b3 --- /dev/null +++ b/gnu/usr.bin/ld/rtld/malloc.c @@ -0,0 +1,481 @@ +/* + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. 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 defined(LIBC_SCCS) && !defined(lint) +/*static char *sccsid = "from: @(#)malloc.c 5.11 (Berkeley) 2/23/91";*/ +static char *rcsid = "$Id: malloc.c,v 1.1 1994/02/13 20:44:09 jkh Exp $"; +#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/types.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/param.h> +#include <sys/mman.h> +#ifndef BSD +#define MAP_COPY MAP_PRIVATE +#define MAP_FILE 0 +#define MAP_ANON 0 +#endif + +#ifndef BSD /* Need do better than this */ +#define NEED_DEV_ZERO 1 +#endif + +#define NULL 0 + +static void morecore(); +static int findbucket(); + +/* + * Pre-allocate mmap'ed pages + */ +#define getpagesize() NBPG +#define NPOOLPAGES (32*1024/NBPG) +static caddr_t pagepool_start, pagepool_end; +static int morepages(); + +/* + * 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 +}; + +#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]; +extern char *sbrk(); + +static int pagesz; /* page size */ +static int pagebucket; /* page size bucket */ + +#ifdef MSTATS +/* + * nmalloc[i] is the difference between the number of mallocs and frees + * for a given block size. + */ +static u_int nmalloc[NBUCKETS]; +#include <stdio.h> +#endif + +#if defined(DEBUG) || defined(RCHECK) +#define ASSERT(p) if (!(p)) botch("p") +#include <stdio.h> +static +botch(s) + char *s; +{ + fprintf(stderr, "\r\nassertion botched: %s\r\n", s); + (void) fflush(stderr); /* just in case user buffered it */ + abort(); +} +#else +#define ASSERT(p) +#endif + +void * +malloc(nbytes) + size_t nbytes; +{ + register union overhead *op; + register int bucket, n; + register 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 = getpagesize(); + if (morepages(NPOOLPAGES) == 0) + return NULL; + op = (union overhead *)(pagepool_start); + n = n - sizeof (*op) - ((int)op & (n - 1)); + if (n < 0) + n += pagesz; + if (n) { + pagepool_start += n; + } + bucket = 0; + amt = 8; + while (pagesz > amt) { + amt <<= 1; + bucket++; + } + pagebucket = bucket; + } + /* + * 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)) { +#ifndef RCHECK + amt = 8; /* size of first bucket */ + bucket = 0; +#else + amt = 16; /* size of first bucket */ + bucket = 1; +#endif + 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(bucket) + int bucket; +{ + register union overhead *op; + register int sz; /* size of desired block */ + int amt; /* amount to allocate */ + int 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 DEBUG + ASSERT(sz > 0); +#else + if (sz <= 0) + return; +#endif + if (sz < pagesz) { + amt = pagesz; + nblks = amt / sz; + } else { + amt = sz + pagesz; + nblks = 1; + } + if (amt > pagepool_end - pagepool_start) + if (morepages(amt/pagesz + 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 +free(cp) + void *cp; +{ + register int size; + register union overhead *op; + + if (cp == NULL) + return; + op = (union overhead *)((caddr_t)cp - sizeof (union overhead)); +#ifdef 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 +} + +/* + * When a program attempts "storage compaction" as mentioned in the + * old malloc man page, it realloc's an already freed block. Usually + * this is the last block it freed; occasionally it might be farther + * back. We have to search all the free lists for the block in order + * to determine its bucket: 1st we make one pass thru the lists + * checking only the first block in each; if that fails we search + * ``realloc_srchlen'' blocks in each list for a match (the variable + * is extern so the caller can modify it). If that fails we just copy + * however many bytes was given to realloc() and hope it's not huge. + */ +int realloc_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */ + +void * +realloc(cp, nbytes) + void *cp; + size_t nbytes; +{ + register u_int onb; + register int i; + union overhead *op; + char *res; + int was_alloced = 0; + + if (cp == NULL) + return (malloc(nbytes)); + op = (union overhead *)((caddr_t)cp - sizeof (union overhead)); + if (op->ov_magic == MAGIC) { + was_alloced++; + i = op->ov_index; + } else { + /* + * Already free, doing "compaction". + * + * Search for the old block of memory on the + * free list. First, check the most common + * case (last element free'd), then (this failing) + * the last ``realloc_srchlen'' items free'd. + * If all lookups fail, then assume the size of + * the memory block being realloc'd is the + * largest possible (so that all "nbytes" of new + * memory are copied into). Note that this could cause + * a memory fault if the old area was tiny, and the moon + * is gibbous. However, that is very unlikely. + */ + if ((i = findbucket(op, 1)) < 0 && + (i = findbucket(op, realloc_srchlen)) < 0) + i = NBUCKETS; + } + 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 (was_alloced) { + 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 + free(cp); + } + if ((res = malloc(nbytes)) == NULL) + return (NULL); + if (cp != res) /* common optimization if "compacting" */ + bcopy(cp, res, (nbytes < onb) ? nbytes : onb); + return (res); +} + +/* + * Search ``srchlen'' elements of each free list for a block whose + * header starts at ``freep''. If srchlen is -1 search the whole list. + * Return bucket number, or -1 if not found. + */ +static +findbucket(freep, srchlen) + union overhead *freep; + int srchlen; +{ + register union overhead *p; + register int i, j; + + for (i = 0; i < NBUCKETS; i++) { + j = 0; + for (p = nextf[i]; p && j != srchlen; p = p->ov_next) { + if (p == freep) + return (i); + j++; + } + } + return (-1); +} + +#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. + */ +mstats(s) + char *s; +{ + register int i, j; + register union overhead *p; + int totfree = 0, + totused = 0; + + fprintf(stderr, "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++) + ; + fprintf(stderr, " %d", j); + totfree += j * (1 << (i + 3)); + } + fprintf(stderr, "\nused:\t"); + for (i = 0; i < NBUCKETS; i++) { + fprintf(stderr, " %d", nmalloc[i]); + totused += nmalloc[i] * (1 << (i + 3)); + } + fprintf(stderr, "\n\tTotal in use: %d, total free: %d\n", + totused, totfree); +} +#endif + + +static int +morepages(n) +int n; +{ + int fd = -1; + int offset; + +#ifdef NEED_DEV_ZERO + fd = open("/dev/zero", O_RDWR, 0); + if (fd == -1) + perror("/dev/zero"); +#endif + + if (pagepool_end - pagepool_start > pagesz) { + caddr_t addr = (caddr_t) + (((int)pagepool_start + pagesz - 1) & ~(pagesz - 1)); + if (munmap(addr, pagepool_end - addr) != 0) + perror("munmap"); + } + + offset = (int)pagepool_start - ((int)pagepool_start & ~(pagesz - 1)); + + if ((pagepool_start = mmap(0, n * pagesz, + PROT_READ|PROT_WRITE, + MAP_ANON|MAP_COPY, 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; +} |