379 lines
12 KiB
C
379 lines
12 KiB
C
/* Declarations for `mmalloc' and friends.
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Copyright 1990, 1991, 1992 Free Software Foundation
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Written May 1989 by Mike Haertel.
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Heavily modified Mar 1992 by Fred Fish. (fnf@cygnus.com)
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA.
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The author may be reached (Email) at the address mike@ai.mit.edu,
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or (US mail) as Mike Haertel c/o Free Software Foundation. */
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#ifndef __MMALLOC_H
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#define __MMALLOC_H 1
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#ifdef __STDC__
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# include <stddef.h>
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# define PTR void *
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# define CONST const
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# define PARAMS(paramlist) paramlist
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# include <limits.h>
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# ifndef NULL
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# define NULL (void *) 0
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# endif
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#else
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# define PTR char *
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# define CONST /* nothing */
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# define PARAMS(paramlist) ()
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# ifndef size_t
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# define size_t unsigned int
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# endif
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# ifndef CHAR_BIT
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# define CHAR_BIT 8
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# endif
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# ifndef NULL
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# define NULL 0
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# endif
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#endif
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#ifndef MIN
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# define MIN(A, B) ((A) < (B) ? (A) : (B))
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#endif
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#define MMALLOC_MAGIC "mmalloc" /* Mapped file magic number */
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#define MMALLOC_MAGIC_SIZE 8 /* Size of magic number buf */
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#define MMALLOC_VERSION 1 /* Current mmalloc version */
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#define MMALLOC_KEYS 16 /* Keys for application use */
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/* The allocator divides the heap into blocks of fixed size; large
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requests receive one or more whole blocks, and small requests
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receive a fragment of a block. Fragment sizes are powers of two,
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and all fragments of a block are the same size. When all the
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fragments in a block have been freed, the block itself is freed. */
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#define INT_BIT (CHAR_BIT * sizeof(int))
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#define BLOCKLOG (INT_BIT > 16 ? 12 : 9)
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#define BLOCKSIZE ((unsigned int) 1 << BLOCKLOG)
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#define BLOCKIFY(SIZE) (((SIZE) + BLOCKSIZE - 1) / BLOCKSIZE)
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/* The difference between two pointers is a signed int. On machines where
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the data addresses have the high bit set, we need to ensure that the
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difference becomes an unsigned int when we are using the address as an
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integral value. In addition, when using with the '%' operator, the
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sign of the result is machine dependent for negative values, so force
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it to be treated as an unsigned int. */
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#define ADDR2UINT(addr) ((unsigned int) ((char *) (addr) - (char *) NULL))
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#define RESIDUAL(addr,bsize) ((unsigned int) (ADDR2UINT (addr) % (bsize)))
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/* Determine the amount of memory spanned by the initial heap table
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(not an absolute limit). */
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#define HEAP (INT_BIT > 16 ? 4194304 : 65536)
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/* Number of contiguous free blocks allowed to build up at the end of
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memory before they will be returned to the system. */
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#define FINAL_FREE_BLOCKS 8
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/* Where to start searching the free list when looking for new memory.
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The two possible values are 0 and heapindex. Starting at 0 seems
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to reduce total memory usage, while starting at heapindex seems to
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run faster. */
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#define MALLOC_SEARCH_START mdp -> heapindex
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/* Address to block number and vice versa. */
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#define BLOCK(A) (((char *) (A) - mdp -> heapbase) / BLOCKSIZE + 1)
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#define ADDRESS(B) ((PTR) (((B) - 1) * BLOCKSIZE + mdp -> heapbase))
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/* Data structure giving per-block information. */
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typedef union
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{
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/* Heap information for a busy block. */
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struct
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{
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/* Zero for a large block, or positive giving the
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logarithm to the base two of the fragment size. */
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int type;
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union
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{
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struct
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{
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size_t nfree; /* Free fragments in a fragmented block. */
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size_t first; /* First free fragment of the block. */
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} frag;
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/* Size (in blocks) of a large cluster. */
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size_t size;
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} info;
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} busy;
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/* Heap information for a free block (that may be the first of
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a free cluster). */
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struct
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{
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size_t size; /* Size (in blocks) of a free cluster. */
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size_t next; /* Index of next free cluster. */
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size_t prev; /* Index of previous free cluster. */
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} free;
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} malloc_info;
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/* List of blocks allocated with `mmemalign' (or `mvalloc'). */
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struct alignlist
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{
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struct alignlist *next;
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PTR aligned; /* The address that mmemaligned returned. */
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PTR exact; /* The address that malloc returned. */
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};
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/* Doubly linked lists of free fragments. */
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struct list
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{
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struct list *next;
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struct list *prev;
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};
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/* Statistics available to the user.
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FIXME: By design, the internals of the malloc package are no longer
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exported to the user via an include file, so access to this data needs
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to be via some other mechanism, such as mmstat_<something> where the
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return value is the <something> the user is interested in. */
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struct mstats
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{
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size_t bytes_total; /* Total size of the heap. */
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size_t chunks_used; /* Chunks allocated by the user. */
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size_t bytes_used; /* Byte total of user-allocated chunks. */
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size_t chunks_free; /* Chunks in the free list. */
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size_t bytes_free; /* Byte total of chunks in the free list. */
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};
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/* Internal structure that defines the format of the malloc-descriptor.
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This gets written to the base address of the region that mmalloc is
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managing, and thus also becomes the file header for the mapped file,
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if such a file exists. */
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struct mdesc
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{
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/* The "magic number" for an mmalloc file. */
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char magic[MMALLOC_MAGIC_SIZE];
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/* The size in bytes of this structure, used as a sanity check when reusing
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a previously created mapped file. */
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unsigned int headersize;
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/* The version number of the mmalloc package that created this file. */
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unsigned char version;
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/* Some flag bits to keep track of various internal things. */
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unsigned int flags;
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/* If a system call made by the mmalloc package fails, the errno is
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preserved for future examination. */
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int errno;
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/* Pointer to the function that is used to get more core, or return core
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to the system, for requests using this malloc descriptor. For memory
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mapped regions, this is the mmap() based routine. There may also be
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a single malloc descriptor that points to an sbrk() based routine
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for systems without mmap() or for applications that call the mmalloc()
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package with a NULL malloc descriptor. */
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PTR (*morecore) PARAMS ((struct mdesc *, ptrdiff_t));
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/* Pointer to the function that causes an abort when the memory checking
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features are activated. By default this is set to abort(), but can
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be set to another function by the application using mmalloc(). */
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void (*abortfunc) PARAMS ((void));
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/* Debugging hook for free. */
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void (*mfree_hook) PARAMS ((PTR, PTR));
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/* Debugging hook for `malloc'. */
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PTR (*mmalloc_hook) PARAMS ((PTR, size_t));
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/* Debugging hook for realloc. */
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PTR (*mrealloc_hook) PARAMS ((PTR, PTR, size_t));
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/* Number of info entries. */
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size_t heapsize;
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/* Pointer to first block of the heap (base of the first block). */
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char *heapbase;
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/* Current search index for the heap table. */
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/* Search index in the info table. */
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size_t heapindex;
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/* Limit of valid info table indices. */
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size_t heaplimit;
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/* Block information table.
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Allocated with malign/__mmalloc_free (not mmalloc/mfree). */
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/* Table indexed by block number giving per-block information. */
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malloc_info *heapinfo;
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/* Instrumentation. */
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struct mstats heapstats;
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/* Free list headers for each fragment size. */
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/* Free lists for each fragment size. */
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struct list fraghead[BLOCKLOG];
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/* List of blocks allocated by memalign. */
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struct alignlist *aligned_blocks;
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/* The base address of the memory region for this malloc heap. This
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is the location where the bookkeeping data for mmap and for malloc
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begins. */
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char *base;
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/* The current location in the memory region for this malloc heap which
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represents the end of memory in use. */
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char *breakval;
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/* The end of the current memory region for this malloc heap. This is
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the first location past the end of mapped memory. */
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char *top;
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/* Open file descriptor for the file to which this malloc heap is mapped.
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This will always be a valid file descriptor, since /dev/zero is used
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by default if no open file is supplied by the client. Also note that
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it may change each time the region is mapped and unmapped. */
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int fd;
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/* An array of keys to data within the mapped region, for use by the
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application. */
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void *keys[MMALLOC_KEYS];
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};
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/* Bits to look at in the malloc descriptor flags word */
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#define MMALLOC_DEVZERO (1 << 0) /* Have mapped to /dev/zero */
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#define MMALLOC_INITIALIZED (1 << 1) /* Initialized mmalloc */
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#define MMALLOC_MMCHECK_USED (1 << 2) /* mmcheck() called already */
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/* Allocate SIZE bytes of memory. */
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extern PTR mmalloc PARAMS ((PTR, size_t));
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/* Re-allocate the previously allocated block in PTR, making the new block
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SIZE bytes long. */
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extern PTR mrealloc PARAMS ((PTR, PTR, size_t));
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/* Allocate NMEMB elements of SIZE bytes each, all initialized to 0. */
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extern PTR mcalloc PARAMS ((PTR, size_t, size_t));
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/* Free a block allocated by `mmalloc', `mrealloc' or `mcalloc'. */
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extern void mfree PARAMS ((PTR, PTR));
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/* Allocate SIZE bytes allocated to ALIGNMENT bytes. */
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extern PTR mmemalign PARAMS ((PTR, size_t, size_t));
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/* Allocate SIZE bytes on a page boundary. */
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extern PTR mvalloc PARAMS ((PTR, size_t));
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/* Activate a standard collection of debugging hooks. */
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extern int mmcheck PARAMS ((PTR, void (*) (void)));
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/* Pick up the current statistics. (see FIXME elsewhere) */
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extern struct mstats mmstats PARAMS ((PTR));
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/* Internal version of `mfree' used in `morecore'. */
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extern void __mmalloc_free PARAMS ((struct mdesc *, PTR));
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/* Hooks for debugging versions. */
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extern void (*__mfree_hook) PARAMS ((PTR, PTR));
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extern PTR (*__mmalloc_hook) PARAMS ((PTR, size_t));
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extern PTR (*__mrealloc_hook) PARAMS ((PTR, PTR, size_t));
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/* A default malloc descriptor for the single sbrk() managed region. */
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extern struct mdesc *__mmalloc_default_mdp;
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/* Initialize the first use of the default malloc descriptor, which uses
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an sbrk() region. */
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extern struct mdesc *__mmalloc_sbrk_init PARAMS ((void));
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/* Grow or shrink a contiguous region using sbrk(). */
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extern PTR __mmalloc_sbrk_morecore PARAMS ((struct mdesc *, int));
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/* Grow or shrink a contiguous mapped region using mmap().
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Works much like sbrk() */
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#if defined(HAVE_MMAP)
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extern PTR __mmalloc_mmap_morecore PARAMS ((struct mdesc *, int));
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#endif
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/* Remap a mmalloc region that was previously mapped. */
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extern PTR __mmalloc_remap_core PARAMS ((struct mdesc *));
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/* Macro to convert from a user supplied malloc descriptor to pointer to the
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internal malloc descriptor. If the user supplied descriptor is NULL, then
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use the default internal version, initializing it if necessary. Otherwise
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just cast the user supplied version (which is void *) to the proper type
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(struct mdesc *). */
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#define MD_TO_MDP(md) \
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((md) == NULL \
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? (__mmalloc_default_mdp == NULL \
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? __mmalloc_sbrk_init () \
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: __mmalloc_default_mdp) \
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: (struct mdesc *) (md))
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#endif /* __MMALLOC_H */
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