| 1 | /* Declarations for `mmalloc' and friends. |
| 2 | Copyright 1990, 1991, 1992 Free Software Foundation |
| 3 | |
| 4 | Written May 1989 by Mike Haertel. |
| 5 | Heavily modified Mar 1992 by Fred Fish. (fnf@cygnus.com) |
| 6 | |
| 7 | The GNU C Library is free software; you can redistribute it and/or |
| 8 | modify it under the terms of the GNU Library General Public License as |
| 9 | published by the Free Software Foundation; either version 2 of the |
| 10 | License, or (at your option) any later version. |
| 11 | |
| 12 | The GNU C Library is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | Library General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU Library General Public |
| 18 | License along with the GNU C Library; see the file COPYING.LIB. If |
| 19 | not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 20 | Boston, MA 02111-1307, USA. |
| 21 | |
| 22 | The author may be reached (Email) at the address mike@ai.mit.edu, |
| 23 | or (US mail) as Mike Haertel c/o Free Software Foundation. */ |
| 24 | |
| 25 | |
| 26 | #ifndef __MMPRIVATE_H |
| 27 | #define __MMPRIVATE_H 1 |
| 28 | |
| 29 | #include "mmalloc.h" |
| 30 | |
| 31 | #ifdef HAVE_LIMITS_H |
| 32 | # include <limits.h> |
| 33 | #else |
| 34 | # ifndef CHAR_BIT |
| 35 | # define CHAR_BIT 8 |
| 36 | # endif |
| 37 | #endif |
| 38 | |
| 39 | #ifndef MIN |
| 40 | # define MIN(A, B) ((A) < (B) ? (A) : (B)) |
| 41 | #endif |
| 42 | |
| 43 | #define MMALLOC_MAGIC "mmalloc" /* Mapped file magic number */ |
| 44 | #define MMALLOC_MAGIC_SIZE 8 /* Size of magic number buf */ |
| 45 | #define MMALLOC_VERSION 1 /* Current mmalloc version */ |
| 46 | #define MMALLOC_KEYS 16 /* Keys for application use */ |
| 47 | |
| 48 | /* The allocator divides the heap into blocks of fixed size; large |
| 49 | requests receive one or more whole blocks, and small requests |
| 50 | receive a fragment of a block. Fragment sizes are powers of two, |
| 51 | and all fragments of a block are the same size. When all the |
| 52 | fragments in a block have been freed, the block itself is freed. */ |
| 53 | |
| 54 | #define INT_BIT (CHAR_BIT * sizeof(int)) |
| 55 | #define BLOCKLOG (INT_BIT > 16 ? 12 : 9) |
| 56 | #define BLOCKSIZE ((unsigned int) 1 << BLOCKLOG) |
| 57 | #define BLOCKIFY(SIZE) (((SIZE) + BLOCKSIZE - 1) / BLOCKSIZE) |
| 58 | |
| 59 | /* The difference between two pointers is a signed int. On machines where |
| 60 | the data addresses have the high bit set, we need to ensure that the |
| 61 | difference becomes an unsigned int when we are using the address as an |
| 62 | integral value. In addition, when using with the '%' operator, the |
| 63 | sign of the result is machine dependent for negative values, so force |
| 64 | it to be treated as an unsigned int. */ |
| 65 | |
| 66 | #define ADDR2UINT(addr) ((unsigned int) ((char *) (addr) - (char *) NULL)) |
| 67 | #define RESIDUAL(addr,bsize) ((unsigned int) (ADDR2UINT (addr) % (bsize))) |
| 68 | |
| 69 | /* Determine the amount of memory spanned by the initial heap table |
| 70 | (not an absolute limit). */ |
| 71 | |
| 72 | #define HEAP (INT_BIT > 16 ? 4194304 : 65536) |
| 73 | |
| 74 | /* Number of contiguous free blocks allowed to build up at the end of |
| 75 | memory before they will be returned to the system. */ |
| 76 | |
| 77 | #define FINAL_FREE_BLOCKS 8 |
| 78 | |
| 79 | /* Where to start searching the free list when looking for new memory. |
| 80 | The two possible values are 0 and heapindex. Starting at 0 seems |
| 81 | to reduce total memory usage, while starting at heapindex seems to |
| 82 | run faster. */ |
| 83 | |
| 84 | #define MALLOC_SEARCH_START mdp -> heapindex |
| 85 | |
| 86 | /* Address to block number and vice versa. */ |
| 87 | |
| 88 | #define BLOCK(A) (((char *) (A) - mdp -> heapbase) / BLOCKSIZE + 1) |
| 89 | |
| 90 | #define ADDRESS(B) ((PTR) (((B) - 1) * BLOCKSIZE + mdp -> heapbase)) |
| 91 | |
| 92 | /* Data structure giving per-block information. */ |
| 93 | |
| 94 | typedef union |
| 95 | { |
| 96 | /* Heap information for a busy block. */ |
| 97 | struct |
| 98 | { |
| 99 | /* Zero for a large block, or positive giving the |
| 100 | logarithm to the base two of the fragment size. */ |
| 101 | int type; |
| 102 | union |
| 103 | { |
| 104 | struct |
| 105 | { |
| 106 | size_t nfree; /* Free fragments in a fragmented block. */ |
| 107 | size_t first; /* First free fragment of the block. */ |
| 108 | } frag; |
| 109 | /* Size (in blocks) of a large cluster. */ |
| 110 | size_t size; |
| 111 | } info; |
| 112 | } busy; |
| 113 | /* Heap information for a free block (that may be the first of |
| 114 | a free cluster). */ |
| 115 | struct |
| 116 | { |
| 117 | size_t size; /* Size (in blocks) of a free cluster. */ |
| 118 | size_t next; /* Index of next free cluster. */ |
| 119 | size_t prev; /* Index of previous free cluster. */ |
| 120 | } free; |
| 121 | } malloc_info; |
| 122 | |
| 123 | /* List of blocks allocated with `mmemalign' (or `mvalloc'). */ |
| 124 | |
| 125 | struct alignlist |
| 126 | { |
| 127 | struct alignlist *next; |
| 128 | PTR aligned; /* The address that mmemaligned returned. */ |
| 129 | PTR exact; /* The address that malloc returned. */ |
| 130 | }; |
| 131 | |
| 132 | /* Doubly linked lists of free fragments. */ |
| 133 | |
| 134 | struct list |
| 135 | { |
| 136 | struct list *next; |
| 137 | struct list *prev; |
| 138 | }; |
| 139 | |
| 140 | /* Statistics available to the user. |
| 141 | FIXME: By design, the internals of the malloc package are no longer |
| 142 | exported to the user via an include file, so access to this data needs |
| 143 | to be via some other mechanism, such as mmstat_<something> where the |
| 144 | return value is the <something> the user is interested in. */ |
| 145 | |
| 146 | struct mstats |
| 147 | { |
| 148 | size_t bytes_total; /* Total size of the heap. */ |
| 149 | size_t chunks_used; /* Chunks allocated by the user. */ |
| 150 | size_t bytes_used; /* Byte total of user-allocated chunks. */ |
| 151 | size_t chunks_free; /* Chunks in the free list. */ |
| 152 | size_t bytes_free; /* Byte total of chunks in the free list. */ |
| 153 | }; |
| 154 | |
| 155 | /* Internal structure that defines the format of the malloc-descriptor. |
| 156 | This gets written to the base address of the region that mmalloc is |
| 157 | managing, and thus also becomes the file header for the mapped file, |
| 158 | if such a file exists. */ |
| 159 | |
| 160 | struct mdesc |
| 161 | { |
| 162 | /* The "magic number" for an mmalloc file. */ |
| 163 | |
| 164 | char magic[MMALLOC_MAGIC_SIZE]; |
| 165 | |
| 166 | /* The size in bytes of this structure, used as a sanity check when reusing |
| 167 | a previously created mapped file. */ |
| 168 | |
| 169 | unsigned int headersize; |
| 170 | |
| 171 | /* The version number of the mmalloc package that created this file. */ |
| 172 | |
| 173 | unsigned char version; |
| 174 | |
| 175 | /* Some flag bits to keep track of various internal things. */ |
| 176 | |
| 177 | unsigned int flags; |
| 178 | |
| 179 | /* If a system call made by the mmalloc package fails, the errno is |
| 180 | preserved for future examination. */ |
| 181 | |
| 182 | int saved_errno; |
| 183 | |
| 184 | /* Pointer to the function that is used to get more core, or return core |
| 185 | to the system, for requests using this malloc descriptor. For memory |
| 186 | mapped regions, this is the mmap() based routine. There may also be |
| 187 | a single malloc descriptor that points to an sbrk() based routine |
| 188 | for systems without mmap() or for applications that call the mmalloc() |
| 189 | package with a NULL malloc descriptor. |
| 190 | |
| 191 | FIXME: For mapped regions shared by more than one process, this |
| 192 | needs to be maintained on a per-process basis. */ |
| 193 | |
| 194 | PTR (*morecore) PARAMS ((struct mdesc *, int)); |
| 195 | |
| 196 | /* Pointer to the function that causes an abort when the memory checking |
| 197 | features are activated. By default this is set to abort(), but can |
| 198 | be set to another function by the application using mmalloc(). |
| 199 | |
| 200 | FIXME: For mapped regions shared by more than one process, this |
| 201 | needs to be maintained on a per-process basis. */ |
| 202 | |
| 203 | void (*abortfunc) PARAMS ((void)); |
| 204 | |
| 205 | /* Debugging hook for free. |
| 206 | |
| 207 | FIXME: For mapped regions shared by more than one process, this |
| 208 | needs to be maintained on a per-process basis. */ |
| 209 | |
| 210 | void (*mfree_hook) PARAMS ((PTR, PTR)); |
| 211 | |
| 212 | /* Debugging hook for `malloc'. |
| 213 | |
| 214 | FIXME: For mapped regions shared by more than one process, this |
| 215 | needs to be maintained on a per-process basis. */ |
| 216 | |
| 217 | PTR (*mmalloc_hook) PARAMS ((PTR, size_t)); |
| 218 | |
| 219 | /* Debugging hook for realloc. |
| 220 | |
| 221 | FIXME: For mapped regions shared by more than one process, this |
| 222 | needs to be maintained on a per-process basis. */ |
| 223 | |
| 224 | PTR (*mrealloc_hook) PARAMS ((PTR, PTR, size_t)); |
| 225 | |
| 226 | /* Number of info entries. */ |
| 227 | |
| 228 | size_t heapsize; |
| 229 | |
| 230 | /* Pointer to first block of the heap (base of the first block). */ |
| 231 | |
| 232 | char *heapbase; |
| 233 | |
| 234 | /* Current search index for the heap table. */ |
| 235 | /* Search index in the info table. */ |
| 236 | |
| 237 | size_t heapindex; |
| 238 | |
| 239 | /* Limit of valid info table indices. */ |
| 240 | |
| 241 | size_t heaplimit; |
| 242 | |
| 243 | /* Block information table. |
| 244 | Allocated with malign/__mmalloc_free (not mmalloc/mfree). */ |
| 245 | /* Table indexed by block number giving per-block information. */ |
| 246 | |
| 247 | malloc_info *heapinfo; |
| 248 | |
| 249 | /* Instrumentation. */ |
| 250 | |
| 251 | struct mstats heapstats; |
| 252 | |
| 253 | /* Free list headers for each fragment size. */ |
| 254 | /* Free lists for each fragment size. */ |
| 255 | |
| 256 | struct list fraghead[BLOCKLOG]; |
| 257 | |
| 258 | /* List of blocks allocated by memalign. */ |
| 259 | |
| 260 | struct alignlist *aligned_blocks; |
| 261 | |
| 262 | /* The base address of the memory region for this malloc heap. This |
| 263 | is the location where the bookkeeping data for mmap and for malloc |
| 264 | begins. */ |
| 265 | |
| 266 | char *base; |
| 267 | |
| 268 | /* The current location in the memory region for this malloc heap which |
| 269 | represents the end of memory in use. */ |
| 270 | |
| 271 | char *breakval; |
| 272 | |
| 273 | /* The end of the current memory region for this malloc heap. This is |
| 274 | the first location past the end of mapped memory. */ |
| 275 | |
| 276 | char *top; |
| 277 | |
| 278 | /* Open file descriptor for the file to which this malloc heap is mapped. |
| 279 | This will always be a valid file descriptor, since /dev/zero is used |
| 280 | by default if no open file is supplied by the client. Also note that |
| 281 | it may change each time the region is mapped and unmapped. */ |
| 282 | |
| 283 | int fd; |
| 284 | |
| 285 | /* An array of keys to data within the mapped region, for use by the |
| 286 | application. */ |
| 287 | |
| 288 | PTR keys[MMALLOC_KEYS]; |
| 289 | |
| 290 | }; |
| 291 | |
| 292 | /* Bits to look at in the malloc descriptor flags word */ |
| 293 | |
| 294 | #define MMALLOC_DEVZERO (1 << 0) /* Have mapped to /dev/zero */ |
| 295 | #define MMALLOC_INITIALIZED (1 << 1) /* Initialized mmalloc */ |
| 296 | #define MMALLOC_MMCHECK_USED (1 << 2) /* mmcheckf() called already */ |
| 297 | |
| 298 | /* Internal version of `mfree' used in `morecore'. */ |
| 299 | |
| 300 | extern void __mmalloc_free PARAMS ((struct mdesc *, PTR)); |
| 301 | |
| 302 | /* Hooks for debugging versions. */ |
| 303 | |
| 304 | extern void (*__mfree_hook) PARAMS ((PTR, PTR)); |
| 305 | extern PTR (*__mmalloc_hook) PARAMS ((PTR, size_t)); |
| 306 | extern PTR (*__mrealloc_hook) PARAMS ((PTR, PTR, size_t)); |
| 307 | |
| 308 | /* A default malloc descriptor for the single sbrk() managed region. */ |
| 309 | |
| 310 | extern struct mdesc *__mmalloc_default_mdp; |
| 311 | |
| 312 | /* Initialize the first use of the default malloc descriptor, which uses |
| 313 | an sbrk() region. */ |
| 314 | |
| 315 | extern struct mdesc *__mmalloc_sbrk_init PARAMS ((void)); |
| 316 | |
| 317 | /* Grow or shrink a contiguous mapped region using mmap(). |
| 318 | Works much like sbrk() */ |
| 319 | |
| 320 | #if defined(HAVE_MMAP) |
| 321 | |
| 322 | extern PTR __mmalloc_mmap_morecore PARAMS ((struct mdesc *, int)); |
| 323 | |
| 324 | #endif |
| 325 | |
| 326 | /* Remap a mmalloc region that was previously mapped. */ |
| 327 | |
| 328 | extern PTR __mmalloc_remap_core PARAMS ((struct mdesc *)); |
| 329 | |
| 330 | /* Macro to convert from a user supplied malloc descriptor to pointer to the |
| 331 | internal malloc descriptor. If the user supplied descriptor is NULL, then |
| 332 | use the default internal version, initializing it if necessary. Otherwise |
| 333 | just cast the user supplied version (which is void *) to the proper type |
| 334 | (struct mdesc *). */ |
| 335 | |
| 336 | #define MD_TO_MDP(md) \ |
| 337 | ((md) == NULL \ |
| 338 | ? (__mmalloc_default_mdp == NULL \ |
| 339 | ? __mmalloc_sbrk_init () \ |
| 340 | : __mmalloc_default_mdp) \ |
| 341 | : (struct mdesc *) (md)) |
| 342 | |
| 343 | #endif /* __MMPRIVATE_H */ |