usr.bin/doscmd/mem.c

   1 /*
   2  * Copyright (c) 1992, 1993, 1996
   3  *      Berkeley Software Design, Inc.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by Berkeley Software
  16  *      Design, Inc.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  *
  30  *      BSDI mem.c,v 2.2 1996/04/08 19:32:57 bostic Exp
  31  *
  32  * $FreeBSD: src/usr.bin/doscmd/mem.c,v 1.2.2.1 2002/04/25 11:04:51 tg Exp $
  33  * $DragonFly: src/usr.bin/doscmd/mem.c,v 1.3 2003/10/04 20:36:43 hmp Exp $
  34  */
  35
  36 #include <stdio.h>
  37 #include "doscmd.h"
  38
  39 #define Mark(x) (*(char *) (x))
  40 #define Owner(x) (*(u_short *) ((char *)(x)+1))
  41 #define Size(x) (*(u_short *) ((char *)(x)+3))
  42 #define Next(x) ((char *)(x) + (Size(x)+1)*16)
  43
  44 /* exports */
  45 char    *dosmem;
  46
  47 /* locals */
  48 static int      dosmem_size;
  49
  50 static char     *next_p = NULL;
  51 static char     *end_p  = (char *)0xB0000L;
  52
  53 static char *
  54 core_alloc(int *size)
  55 {
  56     char *ret;
  57     if (*size) {
  58         if (*size & 0xfff) {
  59             *size = (*size & ~0xfff) + 0x1000;
  60         }
  61     } else {
  62         *size = end_p - next_p;
  63     }
  64
  65     if (next_p + *size > end_p) {
  66         return NULL;
  67     }
  68
  69     ret = next_p;
  70     next_p += *size;
  71     return ret;
  72 }
  73
  74 void
  75 mem_free_owner(int owner)
  76 {
  77     char *mp;
  78
  79     debug(D_MEMORY, "    : freeow(%04x)\n", owner);
  80
  81     for (mp = dosmem; ; mp = Next(mp)) {
  82         if (Owner(mp) == owner)
  83             Owner(mp) = 0;
  84
  85         if (Mark(mp) != 'M')
  86             break;
  87     }
  88 }
  89
  90 static void
  91 mem_print(void)
  92 {
  93     char *mp;
  94
  95     for (mp = dosmem; ; mp = Next(mp)) {
  96         debug(D_ALWAYS, "%8p: mark %c owner %04x size %04x\n",
  97               mp, Mark(mp), Owner(mp), Size(mp));
  98
  99         if (Mark(mp) != 'M')
 100             break;
 101     }
 102 }
 103
 104 void
 105 mem_change_owner(int addr, int owner)
 106 {
 107     char *mp;
 108
 109     debug(D_MEMORY, "%04x: owner (%04x)\n", addr, owner);
 110     addr <<= 4;
 111
 112     for (mp = dosmem; ; mp = Next(mp)) {
 113         if ((int)(mp + 16) == addr)
 114             goto found;
 115
 116         if (Mark(mp) != 'M')
 117             break;
 118     }
 119
 120     debug(D_ALWAYS, "%05x: illegal block in change owner\n", addr);
 121     mem_print();
 122     return;
 123
 124 found:
 125     Owner(mp) = owner;
 126 }
 127
 128 void
 129 mem_init(void)
 130 {
 131     int base, avail_memory;
 132
 133     base = 0x600;
 134     core_alloc(&base);
 135
 136     avail_memory = MAX_AVAIL_SEG * 16 - base;
 137     dosmem = core_alloc(&avail_memory);
 138
 139     if (!dosmem || dosmem != (char *)base)
 140         fatal("internal memory error\n");
 141
 142     dosmem_size = avail_memory / 16;
 143
 144     debug(D_MEMORY, "dosmem = %p base = 0x%x avail = 0x%x (%dK)\n",
 145           dosmem, base, dosmem_size, avail_memory / 1024);
 146
 147     Mark(dosmem) = 'Z';
 148     Owner(dosmem) = 0;
 149     Size(dosmem) = dosmem_size - 1;
 150 }
 151
 152 static void
 153 mem_unsplit(char *mp, int size)
 154 {
 155     char *nmp;
 156
 157     while (Mark(mp) == 'M' && Size(mp) < size) {
 158         nmp = Next(mp);
 159
 160         if (Owner(nmp) != 0)
 161             break;
 162
 163         Size(mp) += Size(nmp) + 1;
 164         Mark(mp) = Mark(nmp);
 165     }
 166 }
 167
 168 static void
 169 mem_split(char *mp, int size)
 170 {
 171     char *nmp;
 172     int rest;
 173
 174     rest = Size(mp) - size;
 175     Size(mp) = size;
 176     nmp = Next(mp);
 177     Mark(nmp) = Mark(mp);
 178     Mark(mp) = 'M';
 179     Owner(nmp) = 0;
 180     Size(nmp) = rest - 1;
 181 }
 182
 183 int
 184 mem_alloc(int size, int owner, int *biggestp)
 185 {
 186     char *mp;
 187     int biggest;
 188
 189     biggest = 0;
 190     for (mp = dosmem; ; mp = Next(mp)) {
 191         if (Owner(mp) == 0) {
 192             if (Size(mp) < size)
 193                 mem_unsplit(mp, size);
 194             if (Size(mp) >= size)
 195                 goto got;
 196
 197             if (Size(mp) > biggest)
 198                 biggest = Size(mp);
 199         }
 200
 201         if (Mark(mp) != 'M')
 202             break;
 203     }
 204
 205     debug(D_MEMORY, "%04x: alloc(%04x, owner %04x) failed -> %d\n",
 206           0, size, owner, biggest);
 207
 208     if (biggestp)
 209         *biggestp = biggest;
 210     return 0;
 211
 212 got:
 213     if (Size(mp) > size)
 214         mem_split(mp, size);
 215     Owner(mp) = owner;
 216     debug(D_MEMORY, "%04x: alloc(%04x, owner %04x)\n",
 217           (int)mp/16 + 1, size, owner);
 218
 219     if (biggestp)
 220         *biggestp = size;
 221     return (int)mp/16 + 1;
 222 }
 223
 224 int
 225 mem_adjust(int addr, int size, int *availp)
 226 {
 227     char *mp;
 228
 229     debug(D_MEMORY, "%04x: adjust(%05x)\n", addr, size);
 230     addr <<= 4;
 231
 232     for (mp = dosmem; ; mp = Next(mp)) {
 233         if ((int)(mp + 16) == addr)
 234             goto found;
 235
 236         if (Mark(mp) != 'M')
 237             break;
 238     }
 239
 240     debug(D_ALWAYS, "%05x: illegal block in adjust\n", addr);
 241     mem_print();
 242     return -2;
 243
 244 found:
 245     if (Size(mp) < size)
 246         mem_unsplit(mp, size);
 247     if (Size(mp) >= size)
 248         goto got;
 249
 250     debug(D_MEMORY, "%04x: adjust(%04x) failed -> %d\n",
 251           (int)mp/16 + 1, size, Size(mp));
 252
 253     if (availp)
 254         *availp = Size(mp);
 255     return -1;
 256
 257 got:
 258     if (Size(mp) > size)
 259         mem_split(mp, size);
 260     debug(D_MEMORY, "%04x: adjust(%04x)\n",
 261           (int)mp/16 + 1, size);
 262
 263     if (availp)
 264         *availp = size;
 265     return 0;
 266 }
 267
 268
 269
 270 #ifdef  MEM_TEST
 271 mem_check (void)
 272 {
 273     struct mem_block *mp;
 274     for (mp = mem_blocks.next; mp != &mem_blocks; mp = mp->next) {
 275         if (mp->addr + mp->size != mp->next->addr)
 276             break;
 277         if (mp->inuse && mp->size == 0)
 278             return (-1);
 279     }
 280
 281     if (mp->next != &mem_blocks)
 282         return (-1);
 283     return (0);
 284 }
 285
 286 char *blocks[10];
 287
 288 main (void)
 289 {
 290     int i;
 291     int n;
 292     int newsize;
 293
 294     mem_init (0, 300);
 295
 296     for (i = 0; i < 100000; i++) {
 297         n = random () % 10;
 298
 299         if (blocks[n]) {
 300             newsize = random () % 20;
 301             if ((newsize & 1) == 0)
 302                 newsize = 0;
 303
 304             if (0)
 305                 printf ("adjust %d %x %d\n",
 306                         n, blocks[n], newsize);
 307             mem_adjust (blocks[n], newsize, NULL);
 308             if (newsize == 0)
 309                 blocks[n] = NULL;
 310         } else {
 311             while ((newsize = random () % 20) == 0)
 312                 ;
 313             if (0)
 314                 printf ("alloc %d %d\n", n, newsize);
 315             blocks[n] = mem_alloc (newsize, NULL);
 316         }
 317         if (mem_check () < 0) {
 318             printf ("==== %d\n", i);
 319             mem_print ();
 320         }
 321     }
 322
 323     mem_print ();
 324 }
 325 #endif /* MEM_TEST */