File: mm_alloc.c

package info (click to toggle)
mm 1.4.2-6
  • links: PTS
  • area: main
  • in suites: bookworm, bullseye, sid
  • size: 1,692 kB
  • sloc: sh: 11,309; ansic: 1,484; makefile: 144
file content (481 lines) | stat: -rw-r--r-- 13,098 bytes parent folder | download | duplicates (5)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
/* ====================================================================
 * Copyright (c) 1999-2006 Ralf S. Engelschall <rse@engelschall.com>
 * Copyright (c) 1999-2006 The OSSP Project <http://www.ossp.org/>
 *
 * 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 acknowledgment:
 *    "This product includes software developed by
 *     Ralf S. Engelschall <rse@engelschall.com>."
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by
 *     Ralf S. Engelschall <rse@engelschall.com>."
 *
 * THIS SOFTWARE IS PROVIDED BY RALF S. ENGELSCHALL ``AS IS'' AND ANY
 * EXPRESSED 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 RALF S. ENGELSCHALL OR
 * ITS 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.
 * ====================================================================
 */

/*
**
**  mm_alloc.c -- Standard Malloc-Style API
**
*/

#define MM_PRIVATE
#include "mm.h"

/*
 * Create a memory pool
 */
MM *mm_create(size_t usize, const char *file)
{
    MM *mm = NULL;
    void *core;
    size_t size;
    size_t maxsize;

    /* defaults */
    maxsize = mm_maxsize();
    if (usize == 0)
        usize = maxsize;
    if (usize > maxsize)
        usize = maxsize;
    if (usize < MM_ALLOC_MINSIZE)
        usize = MM_ALLOC_MINSIZE;

    /* determine size */
    size = usize+SIZEOF_mem_pool;

    /* get a shared memory area */
    if ((core = mm_core_create(size, file)) == NULL)
        return NULL;

    /* fill in the memory pool structure */
    mm = (MM *)core;
    mm->mp_size    = size;
    mm->mp_offset  = SIZEOF_mem_pool;

    /* first element of list of free chunks counts existing chunks */
    mm->mp_freechunks.mc_size      = 0; /* has to be 0 forever */
    mm->mp_freechunks.mc_usize     = 0; /* counts chunks */
    mm->mp_freechunks.mc_u.mc_next = NULL;

    return mm;
}

/*
 * Set permissions on memory pool's underlaying disk files
 */
int mm_permission(MM *mm, mode_t mode, uid_t owner, gid_t group)
{
    if (mm == NULL)
        return -1;
    return mm_core_permission((void *)mm, mode, owner, group);
}

/*
 * Reset a memory pool.
 */
void mm_reset(MM *mm)
{
    if (mm == NULL)
        return;
    mm->mp_offset = SIZEOF_mem_pool;
    mm->mp_freechunks.mc_usize = 0;
    mm->mp_freechunks.mc_u.mc_next = NULL;
    return;
}

/*
 * Destroy a memory pool
 */
void mm_destroy(MM *mm)
{
    if (mm == NULL)
        return;
    /* wipe out the whole area to be safe */
    memset(mm, 0, mm->mp_size);
    /* and delete the core area */
    (void)mm_core_delete((void *)mm);
    return;
}

/*
 * Lock a memory pool
 */
int mm_lock(MM *mm, mm_lock_mode mode)
{
    if (mm == NULL)
        return FALSE;
    return mm_core_lock((void *)mm, mode);
}

/*
 * Unlock a memory pool
 */
int mm_unlock(MM *mm)
{
    if (mm == NULL)
        return FALSE;
    return mm_core_unlock((void *)mm);
}

/*
 * Display debugging information
 */
void mm_display_info(MM *mm)
{
    mem_chunk *mc;
    int nFree;
    int nAlloc;
    int i;

    if (!mm_core_lock((void *)mm, MM_LOCK_RD))
        return;
    mc = &(mm->mp_freechunks);
    nFree   = 0;
    while (mc->mc_u.mc_next != NULL) {
        mc = mc->mc_u.mc_next;
        nFree += mc->mc_size;
    }
    nAlloc = mm->mp_offset-SIZEOF_mem_pool-nFree;

    fprintf(stderr, "Information for MM\n");
    fprintf(stderr, "    memory area     = 0x%lx - 0x%lx\n", (unsigned long)mm, (unsigned long)(mm+mm->mp_size));
    fprintf(stderr, "    memory size     = %d\n", mm->mp_size);
    fprintf(stderr, "    memory offset   = %d\n", mm->mp_offset);
    fprintf(stderr, "    bytes spare     = %d\n", mm->mp_size-mm->mp_offset);
    fprintf(stderr, "    bytes free      = %d (%d chunk%s)\n",
            nFree, mm->mp_freechunks.mc_usize,
            mm->mp_freechunks.mc_usize == 1 ? "" : "s");
    fprintf(stderr, "    bytes allocated = %d\n", nAlloc);

    fprintf(stderr, "    List of free chunks:\n");
    if (mm->mp_freechunks.mc_usize > 0) {
        mc = &(mm->mp_freechunks);
        i = 1;
        while (mc->mc_u.mc_next != NULL) {
            mc = mc->mc_u.mc_next;
            fprintf(stderr, "        chunk #%03d: 0x%lx-0x%lx (%d bytes)\n",
                    i++, (unsigned long)mc, (unsigned long)(mc+mc->mc_size), mc->mc_size);
        }
    }
    else {
        fprintf(stderr, "        <empty-list>\n");
    }
    mm_core_unlock((void *)mm);
    return;
}

/*
 * Insert a chunk to the list of free chunks. Algorithm used is:
 * Insert in sorted manner to the list and merge with previous
 * and/or next chunk when possible to form larger chunks out of
 * smaller ones.
 */
static void mm_insert_chunk(MM *mm, mem_chunk *mcInsert)
{
    mem_chunk *mc;
    mem_chunk *mcPrev;
    mem_chunk *mcPrevPrev;
    mem_chunk *mcNext;

    if (!mm_core_lock((void *)mm, MM_LOCK_RW))
        return;
    mc = &(mm->mp_freechunks);
    mcPrevPrev = mc;
    while (mc->mc_u.mc_next != NULL && (char *)(mc->mc_u.mc_next) < (char *)mcInsert) {
        mcPrevPrev = mc;
        mc = mc->mc_u.mc_next;
    }
    mcPrev = mc;
    mcNext = mc->mc_u.mc_next;
    if (mcPrev == mcInsert || mcNext == mcInsert) {
        mm_core_unlock((void *)mm);
        ERR(MM_ERR_ALLOC, "chunk of memory already in free list");
        return;
    }
    if ((char *)mcPrev+(mcPrev->mc_size) == (char *)mcInsert &&
        (mcNext != NULL && (char *)mcInsert+(mcInsert->mc_size) == (char *)mcNext)) {
        /* merge with previous and next chunk */
        mcPrev->mc_size += mcInsert->mc_size + mcNext->mc_size;
        mcPrev->mc_u.mc_next = mcNext->mc_u.mc_next;
        mm->mp_freechunks.mc_usize -= 1;
    }
    else if ((char *)mcPrev+(mcPrev->mc_size) == (char *)mcInsert &&
             (char *)mcInsert+(mcInsert->mc_size) == ((char *)mm + mm->mp_offset)) {
        /* merge with previous and spare block (to increase spare area) */
        mcPrevPrev->mc_u.mc_next = mcPrev->mc_u.mc_next;
        mm->mp_offset -= (mcInsert->mc_size + mcPrev->mc_size);
        mm->mp_freechunks.mc_usize -= 1;
    }
    else if ((char *)mcPrev+(mcPrev->mc_size) == (char *)mcInsert) {
        /* merge with previous chunk */
        mcPrev->mc_size += mcInsert->mc_size;
    }
    else if (mcNext != NULL && (char *)mcInsert+(mcInsert->mc_size) == (char *)mcNext) {
        /* merge with next chunk */
        mcInsert->mc_size += mcNext->mc_size;
        mcInsert->mc_u.mc_next = mcNext->mc_u.mc_next;
        mcPrev->mc_u.mc_next = mcInsert;
    }
    else if ((char *)mcInsert+(mcInsert->mc_size) == ((char *)mm + mm->mp_offset)) {
        /* merge with spare block (to increase spare area) */
        mm->mp_offset -= mcInsert->mc_size;
    }
    else {
        /* no merging possible, so insert as new chunk */
        mcInsert->mc_u.mc_next = mcNext;
        mcPrev->mc_u.mc_next = mcInsert;
        mm->mp_freechunks.mc_usize += 1;
    }
    mm_core_unlock((void *)mm);
    return;
}

/*
 * Retrieve a chunk from the list of free chunks.  Algorithm used
 * is: Search for minimal-sized chunk which is larger or equal
 * than the request size. But when the retrieved chunk is still a
 * lot larger than the requested size, split out the requested
 * size to not waste memory.
 */
static mem_chunk *mm_retrieve_chunk(MM *mm, size_t size)
{
    mem_chunk *mc;
    mem_chunk **pmcMin;
    mem_chunk *mcRes;
    size_t sMin;
    size_t s;

    if (size == 0)
        return NULL;
    if (mm->mp_freechunks.mc_usize == 0)
        return NULL;
    if (!mm_core_lock((void *)mm, MM_LOCK_RW))
        return NULL;

    /* find best-fitting chunk */
    pmcMin = NULL;
    sMin = mm->mp_size; /* initialize with maximum possible */
    mc = &(mm->mp_freechunks);
    while (mc->mc_u.mc_next != NULL) {
        s = mc->mc_u.mc_next->mc_size;
        if (s >= size && s < sMin) {
            pmcMin = &(mc->mc_u.mc_next);
            sMin = s;
            if (s == size)
                break;
        }
        mc = mc->mc_u.mc_next;
    }

    /* create result chunk */
    if (pmcMin == NULL)
        mcRes = NULL;
    else {
        mcRes = *pmcMin;
        if (mcRes->mc_size >= (size + min_of(2*size,128))) {
            /* split out in part */
            s = mcRes->mc_size - size;
            mcRes->mc_size = size;
            /* add back remaining chunk part as new chunk */
            mc = (mem_chunk *)((char *)mcRes + size);
            mc->mc_size = s;
            mc->mc_u.mc_next = mcRes->mc_u.mc_next;
            *pmcMin = mc;
        }
        else {
            /* split out as a whole */
            *pmcMin = mcRes->mc_u.mc_next;
            mm->mp_freechunks.mc_usize--;
        }
    }

    mm_core_unlock((void *)mm);
    return mcRes;
}

/*
 * Allocate a chunk of memory
 */
void *mm_malloc(MM *mm, size_t usize)
{
    mem_chunk *mc;
    size_t size;
    void *vp;

    if (mm == NULL || usize == 0)
        return NULL;
    size = mm_core_align2word(SIZEOF_mem_chunk+usize);
    if ((mc = mm_retrieve_chunk(mm, size)) != NULL) {
        mc->mc_usize = usize;
        return &(mc->mc_u.mc_base.mw_cp);
    }
    if (!mm_core_lock((void *)mm, MM_LOCK_RW))
        return NULL;
    if ((mm->mp_size - mm->mp_offset) < size) {
        mm_core_unlock((void *)mm);
        ERR(MM_ERR_ALLOC, "out of memory");
        errno = ENOMEM;
        return NULL;
    }
    mc = (mem_chunk *)((char *)mm + mm->mp_offset);
    mc->mc_size  = size;
    mc->mc_usize = usize;
    vp = (void *)&(mc->mc_u.mc_base.mw_cp);
    mm->mp_offset += size;
    mm_core_unlock((void *)mm);
    return vp;
}

/*
 * Reallocate a chunk of memory
 */
void *mm_realloc(MM *mm, void *ptr, size_t usize)
{
    size_t size;
    mem_chunk *mc;
    void *vp;

    if (mm == NULL || usize == 0)
        return NULL;
    if (ptr == NULL)
        return mm_malloc(mm, usize); /* POSIX.1 semantics */
    mc = (mem_chunk *)((char *)ptr - SIZEOF_mem_chunk);
    if (usize <= mc->mc_usize) {
        mc->mc_usize = usize;
        return ptr;
    }
    size = mm_core_align2word(SIZEOF_mem_chunk+usize);
    if (size <= mc->mc_size) {
        mc->mc_usize = usize;
        return ptr;
    }
    if ((vp = mm_malloc(mm, usize)) == NULL)
        return NULL;
    memcpy(vp, ptr, mc->mc_usize);
    mm_free(mm, ptr);
    return vp;
}

/*
 * Free a chunk of memory
 */
void mm_free(MM *mm, void *ptr)
{
    mem_chunk *mc;

    if (mm == NULL || ptr == NULL)
        return;
    mc = (mem_chunk *)((char *)ptr - SIZEOF_mem_chunk);
    mm_insert_chunk(mm, mc);
    return;
}

/*
 * Allocate and initialize a chunk of memory
 */
void *mm_calloc(MM *mm, size_t number, size_t usize)
{
    void *vp;

    if (mm == NULL || number*usize == 0)
        return NULL;
    if ((vp = mm_malloc(mm, number*usize)) == NULL)
        return NULL;
    memset(vp, 0, number*usize);
    return vp;
}

/*
 * Duplicate a string
 */
char *mm_strdup(MM *mm, const char *str)
{
    int n;
    void *vp;

    if (mm == NULL || str == NULL)
        return NULL;
    n = strlen(str);
    if ((vp = mm_malloc(mm, n+1)) == NULL)
        return NULL;
    memcpy(vp, str, n+1);
    return vp;
}

/*
 * Determine user size of a memory chunk
 */
size_t mm_sizeof(MM *mm, const void *ptr)
{
    mem_chunk *mc;

    if (mm == NULL || ptr == NULL)
        return -1;
    mc = (mem_chunk *)((char *)ptr - SIZEOF_mem_chunk);
    return mc->mc_usize;
}

/*
 * Determine maximum size of an allocateable memory pool
 */
size_t mm_maxsize(void)
{
    return (mm_core_maxsegsize()-SIZEOF_mem_pool);
}

/*
 * Determine available memory
 */
size_t mm_available(MM *mm)
{
    mem_chunk *mc;
    int nFree;

    if (!mm_core_lock((void *)mm, MM_LOCK_RD))
        return 0;
    nFree = mm->mp_size-mm->mp_offset;
    mc = &(mm->mp_freechunks);
    while (mc->mc_u.mc_next != NULL) {
        mc = mc->mc_u.mc_next;
        nFree += mc->mc_size;
    }
    mm_core_unlock((void *)mm);
    return nFree;
}

/*
 * Return last error string
 */
char *mm_error(void)
{
    return mm_lib_error_get();
}

/*EOF*/