usr.bin/doscmd/ems.c

   1 /*-
   2  * Copyright (c) 1997 Helmut Wirth <hfwirth@ping.at>
   3  * 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 immediately at the beginning of the file, witout modification,
  10  *    this list of conditions, and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * $FreeBSD: src/usr.bin/doscmd/ems.c,v 1.3.2.2 2002/04/25 11:04:51 tg Exp $
  29  * $DragonFly: src/usr.bin/doscmd/ems.c,v 1.4 2005/10/30 23:00:57 swildner Exp $
  30  */
  31
  32 /*
  33  * EMS memory emulation
  34  *
  35  * To emulate Expanded Memory we use a DOS driver (emsdriv.sys) which
  36  * routes calls to int 0x67 to this emulator routine. The main entry point
  37  * is ems_entry(..). The emulator needs to be initialized before the first
  38  * call. The first step of the initialization is done during program startup
  39  * the second part is done during DOS boot, from a call of the DOS driver.
  40  * The DOS driver is neccessary because DOS programs look for it to
  41  * determine if EMS is available.
  42  *
  43  * To emulate a configurable amount of EMS memory we use a file created
  44  * at startup with the size of the configured EMS memory. This file is
  45  * mapped into the EMS window like any DOS memory manager would do, using
  46  * mmap calls.
  47  *
  48  * The emulation follows the LIM EMS 4.0 standard. Not all functions of it
  49  * are implemented yet. The "alter page map and jump" and "alter page map
  50  * and call" functions are not implemented, because they are rather hard to
  51  * do. (It would mean a call to the emulator executes a routine in EMS
  52  * memory and returns to the emulator, the emulator switches the page map
  53  * and then returns to the DOS program.) LINUX does not emulate this
  54  * functions and I think they were very rarely used by DOS applications.
  55  *
  56  * Credits: To the writers of LINUX dosemu, I looked at their code
  57  */
  58
  59 #include <sys/types.h>
  60 #include <sys/param.h>
  61 #include <sys/mman.h>
  62 #include <unistd.h>
  63
  64 #include "doscmd.h"
  65 #include "ems.h"
  66
  67 /* Will be configurable */
  68 u_long ems_max_size   = EMS_MAXSIZE * 1024;
  69 u_long ems_frame_addr = EMS_FRAME_ADDR;
  70
  71 /*
  72  * Method for EMS: Allocate a mapfile with the size of EMS memory
  73  * and map the needed part into the page frame
  74  */
  75
  76 #define EMS_MAP_PATH    "/var/tmp/"     /* Use a big file system */
  77 #define EMS_MAP_FILE    "doscmd.XXXXXX"
  78 static int mapfile_fd = -1;
  79
  80 /* Pages are always 16 kB in size. The page frame is 64 kB, there are
  81  * 4 positions (0..3) for a page to map in. The pages are numbered from 0 to
  82  * the highest 16 kB page in the mapfile, depending on the EMS size
  83  */
  84
  85 EMS_mapping_context ems_mapping_context;
  86
  87 /* Handle and page management (see ems.h) */
  88
  89 /* The handle array. If the pointer is NULL, the handle is unallocated */
  90 static EMS_handle *ems_handle[EMS_NUM_HANDLES];
  91 static u_long ems_alloc_handles;
  92 /* The active handle, if any */
  93 static short active_handle;
  94
  95 /* The page array. It is malloced at runtime, depending on the total
  96  * allocation size
  97  */
  98
  99 static EMS_page *ems_page = NULL;
 100 static u_long ems_total_pages;
 101 static u_long ems_alloc_pages;
 102 static u_long ems_free_pages;
 103
 104 /* Local structure used for region copy and move operations */
 105
 106 struct copydesc {
 107 #define SRC_EMS 1
 108 #define DST_EMS 2
 109     short     copytype;         /* Type of source and destination memory */
 110     EMS_addr  src_addr;         /* Combined pointer for source */
 111     EMS_addr  dst_addr;         /* Combined pointer for destination */
 112     u_long  rest_len;           /* Lenght to copy */
 113 };
 114
 115
 116 /* Local prototypes */
 117 static int      init_mapfile(void);
 118 static void     map_page(u_long, u_char, short, int);
 119 static EMS_handle       *get_new_handle(long);
 120 static void     context_to_handle(short);
 121 static long     find_next_free_handle(void);
 122 static short    lookup_handle(Hname *hp);
 123 static void     allocate_pages_to_handle(u_short, long);
 124 static void     allocate_handle(short, long);
 125 static void     reallocate_pages_to_handle(u_short, long);
 126 static void     free_handle(short);
 127 static void     free_pages_of_handle(short);
 128 static void     restore_context(EMS_mapping_context *);
 129 static void     save_context_to_dos(EMScontext *);
 130 static int      check_saved_context(EMScontext *);
 131 static void     *get_valid_pointer(u_short, u_short, u_long);
 132 static u_long   move_ems_to_conv(short, u_short, u_short, u_long, u_long);
 133 static u_long   move_conv_to_ems(u_long, u_short, u_short, u_short, u_long);
 134 static u_long   move_ems_to_ems(u_short, u_short, u_short, u_short,
 135                                 u_short, u_short, u_long);
 136
 137 /*
 138  * EMS initialization routine: Return 1, if successful, return 0 if
 139  * init problem or EMS disabled
 140  */
 141
 142 int
 143 ems_init(void)
 144 {
 145     unsigned i;
 146
 147     if (ems_max_size == 0)
 148         return 0;
 149     if (init_mapfile() == 0)
 150         return 0;
 151     /* Sanity */
 152     bzero((void *)(&ems_handle[0]), sizeof(ems_handle));
 153     ems_total_pages = ems_max_size / EMS_PAGESIZE;
 154     ems_alloc_pages = 0;
 155     ems_free_pages = ems_total_pages;
 156     ems_alloc_handles = 0;
 157     active_handle = 0;
 158     /* Malloc the page array */
 159     ems_page = (EMS_page *)malloc(sizeof(EMS_page) * ems_total_pages);
 160     if (ems_page == NULL) {
 161         debug(D_ALWAYS, "Could not malloc page array, EMS disabled\n");
 162         ems_frame_addr = 0;
 163         ems_max_size = 0;
 164         ems_total_pages = 0;
 165         return 0;
 166     }
 167     for (i = 0; i < ems_total_pages; i++) {
 168         ems_page[i].handle = 0;
 169         ems_page[i].status = EMS_FREE;
 170     }
 171     debug(D_EMS, "EMS: Emulation init OK.\n");
 172     return 1;
 173 }
 174
 175
 176 /* Main entry point */
 177
 178 void
 179 ems_entry(regcontext_t *REGS)
 180 {
 181     /*
 182      * If EMS is not enabled, the DOS ems.exe module should not have
 183      * been loaded. If it is loaded anyway, report software malfunction
 184      */
 185     if (ems_max_size == 0) {
 186         R_AH = EMS_SW_MALFUNC;
 187         debug(D_EMS, "EMS emulation not enabled\n");
 188         return;
 189     }
 190
 191     switch (R_AH)
 192     {
 193         case GET_MANAGER_STATUS:
 194             debug(D_EMS, "EMS: Get manager status\n");
 195             R_AH = EMS_SUCCESS;
 196             break;
 197
 198         case GET_PAGE_FRAME_SEGMENT:
 199             debug(D_EMS, "EMS: Get page frame segment\n");
 200             R_BX = ems_frame_addr >> 4;
 201             R_AH = EMS_SUCCESS;
 202             break;
 203
 204         case GET_PAGE_COUNTS:
 205             R_BX = ems_total_pages - ems_alloc_pages;
 206             R_DX = ems_total_pages;
 207             debug(D_EMS, "EMS: Get page count: Returned total=%d, free=%d\n",
 208                 R_DX, R_BX);
 209             R_AH = EMS_SUCCESS;
 210             break;
 211
 212         case GET_HANDLE_AND_ALLOCATE:
 213         {
 214             u_short npages;
 215             short handle;
 216
 217             npages = R_BX;
 218             debug(D_EMS, "EMS: Get handle and allocate %d pages: ", npages);
 219
 220             /* Enough handles? */
 221             if ((handle = find_next_free_handle())  < 0) {
 222                 debug(D_EMS,"Return error:No handles\n");
 223                 R_AH = EMS_OUT_OF_HANDLES;
 224                 break;
 225             }
 226             /* Enough memory for this request ? */
 227             if (npages > ems_free_pages) {
 228                 debug(D_EMS,"Return error:Request too big\n");
 229                 R_AH = EMS_OUT_OF_LOG;
 230                 break;
 231             }
 232             if (npages > ems_total_pages) {
 233                 debug(D_EMS,"Return error:Request too big\n");
 234                 R_AH = EMS_OUT_OF_PHYS;
 235                 break;
 236             }
 237             /* Not allowed to allocate zero pages with this function */
 238             if (npages == 0) {
 239                 debug(D_EMS,"Return error:Cannot allocate 0 pages\n");
 240                 R_AH = EMS_ZERO_PAGES;
 241                 break;
 242             }
 243             /* Allocate the handle */
 244             allocate_handle(handle, npages);
 245
 246             /* Allocate the pages */
 247             allocate_pages_to_handle(handle, npages);
 248             R_DX = handle;
 249             R_AH = EMS_SUCCESS;
 250             debug(D_EMS,"Return success:Handle = %d\n", handle);
 251             break;
 252         }
 253
 254         case MAP_UNMAP:
 255         {
 256             u_char position;
 257             u_short hpagenum, spagenum;
 258             short handle;
 259
 260             debug(D_EMS, "EMS: Map/Unmap handle=%d, pos=%d, pagenum=%d ",
 261                 R_DX, R_AL, R_BX);
 262             handle = R_DX;
 263             position = R_AL;
 264             if (position > 3) {
 265                 debug(D_EMS, "invalid position\n");
 266                 R_AH = EMS_ILL_PHYS;
 267                 break;
 268             }
 269             hpagenum = R_BX;
 270             /* This succeeds without a valid handle ! */
 271             if (hpagenum == 0xffff) {
 272                 /* Unmap only */
 273                 map_page(0, position, handle, 1);
 274                 debug(D_EMS, "(unmap only) success\n");
 275                 R_AH = EMS_SUCCESS;
 276                 break;
 277             }
 278             if (handle > 255 || handle == 0 || ems_handle[handle] == NULL) {
 279                 R_AH = EMS_INV_HANDLE;
 280                 debug(D_EMS, "invalid handle\n");
 281                 break;
 282             }
 283             if (hpagenum >= ems_handle[handle]->npages) {
 284                 R_AH = EMS_LOGPAGE_TOOBIG;
 285                 debug(D_EMS, "invalid pagenumber\n");
 286                 break;
 287             }
 288             spagenum = ems_handle[handle]->pagenum[hpagenum];
 289             map_page(spagenum, position, handle, 0);
 290             debug(D_EMS, "success\n");
 291             R_AH = EMS_SUCCESS;
 292             break;
 293         }
 294
 295         case DEALLOCATE_HANDLE:
 296         {
 297             short handle;
 298
 299             /* Handle valid ? */
 300             handle = R_DX;
 301             debug(D_EMS, "EMS: Deallocate handle %d\n", handle);
 302             if (handle > 255 || ems_handle[handle] == NULL) {
 303                 R_AH = EMS_INV_HANDLE;
 304                 break;
 305             }
 306             /* Mapping context saved ? */
 307             if (ems_handle[handle]->mcontext != NULL) {
 308                 R_AH = EMS_SAVED_MAP;
 309                 break;
 310             }
 311
 312             free_pages_of_handle(handle);
 313             free_handle(handle);
 314             R_AH = EMS_SUCCESS;
 315             break;
 316         }
 317
 318         case GET_EMM_VERSION:
 319             debug(D_EMS, "EMS: Get version\n");
 320             R_AL = EMS_VERSION;
 321             R_AH = EMS_SUCCESS;
 322             break;
 323
 324         case SAVE_PAGE_MAP:
 325         {
 326             short handle;
 327
 328             debug(D_EMS, "EMS: Save page map\n");
 329             handle = R_DX;
 330             if (handle > 255 || handle == 0 || ems_handle[handle] == NULL) {
 331                 R_AH = EMS_INV_HANDLE;
 332                 break;
 333             }
 334             if (ems_handle[handle]->mcontext != NULL) {
 335                 /* There is already a context saved */
 336                 if (memcmp((void *)ems_handle[handle]->mcontext,
 337                            (void *)&ems_mapping_context,
 338                            sizeof(EMS_mapping_context)) == 0)
 339                      R_AH = EMS_ALREADY_SAVED;
 340                 else
 341                      R_AH = EMS_NO_ROOM_TO_SAVE;
 342                 break;
 343             }
 344             context_to_handle(handle);
 345             R_AH = EMS_SUCCESS;
 346             break;
 347         }
 348
 349         case RESTORE_PAGE_MAP:
 350         {
 351             short handle;
 352
 353             debug(D_EMS, "EMS: Restore page map\n");
 354             handle = R_DX;
 355             if (handle > 255 || handle == 0 || ems_handle[handle] == NULL) {
 356                 R_AH = EMS_INV_HANDLE;
 357                 break;
 358             }
 359             if (ems_handle[handle]->mcontext == NULL) {
 360                 R_AH = EMS_NO_SAVED_CONTEXT;
 361                 break;
 362             }
 363             restore_context(ems_handle[handle]->mcontext);
 364             free((void *)ems_handle[handle]->mcontext);
 365             ems_handle[handle]->mcontext = NULL;
 366             R_AH = EMS_SUCCESS;
 367             break;
 368         }
 369
 370         case RESERVED_1:
 371         case RESERVED_2:
 372             debug(D_ALWAYS, "Reserved function called: %02x\n", R_AH);
 373             R_AH = EMS_FUNC_NOSUP;
 374             break;
 375
 376         case GET_HANDLE_COUNT:
 377             debug(D_EMS, "EMS: Get handle count\n");
 378             R_BX = ems_alloc_handles + 1;
 379             R_AH = EMS_SUCCESS;
 380             break;
 381
 382         case GET_PAGES_OWNED:
 383         {
 384             short handle;
 385
 386             debug(D_EMS, "EMS: Get pages owned\n");
 387             /* Handle valid ? */
 388             handle = R_DX;
 389             if (handle > 255 || ems_handle[handle] == NULL) {
 390                 R_AH = EMS_INV_HANDLE;
 391                 break;
 392             }
 393             if (handle == 0)
 394                 R_BX = 0;
 395             else
 396                 R_BX = ems_handle[handle]->npages;
 397             R_AH = EMS_SUCCESS;
 398             break;
 399         }
 400
 401         case GET_PAGES_FOR_ALL:
 402         {
 403             EMShandlepage *ehp;
 404             unsigned safecount;
 405             int i;
 406
 407             debug(D_EMS, "EMS: Get pages for all\n");
 408             /* Get the address passed from DOS app */
 409             ehp = (EMShandlepage *)get_valid_pointer(R_ES, R_DI,
 410                         sizeof(EMShandlepage) * ems_alloc_handles);
 411             if (ehp == NULL) {
 412                 R_AH = EMS_SW_MALFUNC;
 413                 break;
 414             }
 415
 416             R_BX = ems_alloc_handles;
 417             safecount = 0;
 418             for (i = 0; i < 255; i++) {
 419                 if (ems_handle[i] != NULL) {
 420                     if (safecount > (ems_alloc_handles+1))
 421                         fatal("EMS: ems_alloc_handles is wrong, "
 422                               "cannot continue\n");
 423                     ehp->handle = i;
 424                     ehp->npages = ems_handle[i]->npages;
 425                     ehp++;
 426                     safecount++;
 427                 }
 428             }
 429             R_AH = EMS_SUCCESS;
 430             break;
 431         }
 432
 433         case PAGE_MAP:
 434         /* This function is a nuisance. It was invented to save time and
 435          * memory, but in our case it is useless. We have to support it
 436          * but we use the same save memory as for the page map function.
 437          * It uses only 20 bytes anyway. We store/restore the entire mapping
 438          */
 439         case PAGE_MAP_PARTIAL:
 440         {
 441             int subfunction;
 442             EMScontext *src, *dest;
 443
 444             debug(D_EMS, "EMS: Page map ");
 445             subfunction = R_AL;
 446             if (R_AH == PAGE_MAP_PARTIAL) {
 447                 debug(D_EMS, "partial ");
 448                 /* Page map partial has slightly different subfunctions
 449                  * GET_SET does not exist and is GET_SIZE in this case
 450                  */
 451                 if (subfunction == GET_SET)
 452                     subfunction = GET_SIZE;
 453             }
 454             switch (subfunction)
 455             {
 456                 case GET:
 457                 {
 458                     debug(D_EMS, "get\n");
 459                     /* Get the address passed from DOS app */
 460                     dest = (EMScontext *)get_valid_pointer(R_ES, R_DI,
 461                         sizeof(EMScontext));
 462                     if (dest == NULL) {
 463                         R_AH = EMS_SW_MALFUNC;
 464                         break;
 465                     }
 466                     save_context_to_dos(dest);
 467                     R_AH = EMS_SUCCESS;
 468                     break;
 469                 }
 470                 case SET:
 471                 {
 472                     debug(D_EMS, "set\n");
 473                     src = (EMScontext *)get_valid_pointer(R_DS, R_SI,
 474                         sizeof(EMScontext));
 475                     if (src == NULL) {
 476                         R_AH = EMS_SW_MALFUNC;
 477                         break;
 478                     }
 479                     if (check_saved_context(src) == 0) {
 480                         R_AH = EMS_SAVED_CONTEXT_BAD;
 481                         break;
 482                     }
 483                     restore_context(&src->ems_saved_context);
 484                     R_AH = EMS_SUCCESS;
 485                     break;
 486                 }
 487                 case GET_SET:
 488                 {
 489                     debug(D_EMS, "get/set\n");
 490                     dest = (EMScontext *)get_valid_pointer(R_ES, R_DI,
 491                         sizeof(EMScontext));
 492                     if (dest == NULL) {
 493                         R_AH = EMS_SW_MALFUNC;
 494                         break;
 495                     }
 496                     save_context_to_dos(dest);
 497                     src = (EMScontext *)get_valid_pointer(R_DS, R_SI,
 498                         sizeof(EMScontext));
 499                     if (src == NULL) {
 500                         R_AH = EMS_SW_MALFUNC;
 501                         break;
 502                     }
 503                     if (check_saved_context(src) == 0) {
 504                         R_AH = EMS_SAVED_CONTEXT_BAD;
 505                         break;
 506                     }
 507                     restore_context(&src->ems_saved_context);
 508                     R_AH = EMS_SUCCESS;
 509                     break;
 510                 }
 511                 case GET_SIZE:
 512                     debug(D_EMS, "get size\n");
 513                     R_AL = (sizeof(EMScontext) + 1) & 0xfe;
 514                     R_AH = EMS_SUCCESS;
 515                     break;
 516                 default:
 517                     debug(D_EMS, "invalid subfunction\n");
 518                     R_AH = EMS_INVALID_SUB;
 519                     break;
 520             }
 521             break;
 522         }
 523
 524         case MAP_UNMAP_MULTI_HANDLE:
 525         {
 526             u_char position;
 527             u_short hpagenum, spagenum;
 528             short handle;
 529             EMSmapunmap *mp;
 530             int n_entry, i;
 531
 532
 533             debug(D_EMS, "EMS: Map/Unmap multiple ");
 534
 535             if ((n_entry = R_CX) > 3) {
 536                 R_AH = EMS_ILL_PHYS;
 537             }
 538
 539             /* This is valid according to the LIM EMS 4.0 spec */
 540             if (n_entry == 0) {
 541                 R_AH = EMS_SUCCESS;
 542                 break;
 543             }
 544
 545             handle = R_DX;
 546             if (handle > 255 || handle == 0 || ems_handle[handle] == NULL) {
 547                 R_AH = EMS_INV_HANDLE;
 548                 break;
 549             }
 550
 551             mp = (EMSmapunmap *)get_valid_pointer(R_DS, R_SI,
 552                         sizeof(EMSmapunmap) * n_entry);
 553             if (mp == NULL) {
 554                 R_AH = EMS_SW_MALFUNC;
 555                 break;
 556             }
 557
 558             R_AH = EMS_SUCCESS;
 559             /* Walk through the table and map/unmap */
 560             for (i = 0; i < n_entry; i++) {
 561                 hpagenum = mp->log;
 562                 /* Method is in R_AL */
 563                 if (R_AL == 0) {
 564                     debug(D_EMS, "phys page method\n");
 565                     if (mp->phys <= 3) {
 566                         position = mp->phys;
 567                     } else {
 568                         R_AH = EMS_ILL_PHYS;
 569                         break;
 570                     }
 571                 } else if (R_AL == 1) {
 572                     /* Compute position from segment address */
 573                     u_short p_seg;
 574
 575                     debug(D_EMS, "segment method\n");
 576                     p_seg = mp->phys;
 577                     p_seg -= ems_frame_addr;
 578                     p_seg /= EMS_PAGESIZE;
 579                     if (p_seg <= 3) {
 580                         position = p_seg;
 581                     } else {
 582                         R_AH = EMS_ILL_PHYS;
 583                         break;
 584                     }
 585                 } else {
 586                     debug(D_EMS, "invalid subfunction\n");
 587                     R_AH = EMS_INVALID_SUB;
 588                     break;
 589                 }
 590
 591                 mp++;
 592                 if (hpagenum == 0xffff) {
 593                     /* Unmap only */
 594                     map_page(0, position, handle, 1);
 595                     continue;
 596                 }
 597                 if (hpagenum >= ems_handle[handle]->npages) {
 598                     R_AH = EMS_LOGPAGE_TOOBIG;
 599                     break;
 600                 }
 601                 spagenum = ems_handle[handle]->pagenum[hpagenum];
 602                 map_page(spagenum, position, handle, 0);
 603             }
 604             break;
 605         }
 606
 607         case REALLOC_PAGES:
 608         {
 609             short handle;
 610             u_long newpages;
 611
 612             debug(D_EMS, "EMS: Realloc pages ");
 613
 614             handle = R_DX;
 615             if (handle > 255 || handle == 0 || ems_handle[handle] == NULL) {
 616                 R_AH = EMS_INV_HANDLE;
 617                 debug(D_EMS, "invalid handle\n");
 618                 break;
 619             }
 620             newpages = R_BX;
 621             debug(D_EMS, "changed from %ld to %ld pages\n",
 622                 ems_handle[handle]->npages, newpages);
 623
 624             /* Case 1: Realloc to zero pages */
 625             if (newpages == 0) {
 626                 free_pages_of_handle(handle);
 627                 R_AH = EMS_SUCCESS;
 628                 break;
 629             }
 630             /* Case 2: New allocation is equal to allocated number */
 631             if (newpages == ems_handle[handle]->npages) {
 632                 R_AH = EMS_SUCCESS;
 633                 break;
 634             }
 635             /* Case 3: Reallocate to bigger and smaller sizes */
 636             if (newpages > ems_handle[handle]->npages) {
 637                 if (newpages > ems_free_pages) {
 638                     R_AH = EMS_OUT_OF_LOG;
 639                     break;
 640                 }
 641                 if (newpages > ems_total_pages) {
 642                     R_AH = EMS_OUT_OF_PHYS;
 643                     break;
 644                 }
 645             }
 646             reallocate_pages_to_handle(handle, newpages);
 647             R_AH = EMS_SUCCESS;
 648             break;
 649         }
 650
 651         /* We do not support nonvolatile pages */
 652         case HANDLE_ATTRIBUTES:
 653             debug(D_EMS, "Handle attributes called\n");
 654             switch (R_AL) {
 655                 case GET:
 656                 case SET:
 657                     R_AH = EMS_FEAT_NOSUP;
 658                     break;
 659                 case HANDLE_CAPABILITY:
 660                     R_AL = 0;           /* Volatile only */
 661                     R_AH = EMS_SUCCESS;
 662                     break;
 663                 default:
 664                     R_AH = EMS_FUNC_NOSUP;
 665                     break;
 666             }
 667             break;
 668
 669         case HANDLE_NAME:
 670         {
 671             short handle;
 672             Hname *hp;
 673
 674             handle = R_DX;
 675             if (handle > 255 || handle == 0 || ems_handle[handle] == NULL) {
 676                 R_AH = EMS_INV_HANDLE;
 677                 debug(D_EMS, "invalid handle\n");
 678                 break;
 679             }
 680             switch (R_AL) {
 681                 case GET:
 682                     if ((hp = (Hname *)get_valid_pointer(R_ES, R_DI, 8))
 683                      == NULL) {
 684                         R_AH = EMS_SW_MALFUNC;
 685                         break;
 686                     }
 687                     *hp = ems_handle[handle]->hname;
 688                     R_AH = EMS_SUCCESS;
 689                     break;
 690
 691                 case SET:
 692                     if ((hp = (Hname *)get_valid_pointer(R_DS, R_SI, 8))
 693                      == NULL) {
 694                         R_AH = EMS_SW_MALFUNC;
 695                         break;
 696                     }
 697                     /* If the handle name is not 0, it may not exist */
 698                     if ((hp->ul_hn[0] | hp->ul_hn[1]) != 0) {
 699                         if (lookup_handle(hp) == 0) {
 700                             ems_handle[handle]->hname = *hp;
 701                             R_AH = EMS_SUCCESS;
 702                         } else {
 703                             R_AH = EMS_NAME_EXISTS;
 704                             break;
 705                         }
 706                     } else {
 707                         /* Name is deleted (set to zeros) */
 708                         ems_handle[handle]->hname = *hp;
 709                         R_AH = EMS_SUCCESS;
 710                     }
 711                     break;
 712
 713                 default:
 714                     R_AH = EMS_FUNC_NOSUP;
 715                     break;
 716             }
 717             break;
 718         }
 719
 720         case HANDLE_DIRECTORY:
 721         {
 722             int i;
 723             EMShandledir *hdp;
 724             Hname *hp;
 725             short handle;
 726
 727             switch(R_AL) {
 728                 case GET:
 729                     hdp = (EMShandledir *)get_valid_pointer(R_ES, R_DI,
 730                         sizeof(EMShandledir) * ems_alloc_handles);
 731                     if (hdp == NULL) {
 732                         R_AH = EMS_SW_MALFUNC;
 733                         break;
 734                     }
 735                     for (i = 0; i < EMS_NUM_HANDLES; i++) {
 736                         if (ems_handle[i] != NULL) {
 737                             hdp->log = i;
 738                             hdp->name = ems_handle[i]->hname;
 739                         }
 740                     }
 741                     R_AH = EMS_SUCCESS;
 742                     break;
 743
 744                 case HANDLE_SEARCH:
 745                     hp = (Hname *)get_valid_pointer(R_DS, R_SI, 8);
 746                     if (hp == NULL) {
 747                         R_AH = EMS_SW_MALFUNC;
 748                         break;
 749                     }
 750                     /* Cannot search for NULL handle name */
 751                     if ((hp->ul_hn[0] | hp->ul_hn[1]) != 0) {
 752                         R_AH = EMS_NAME_EXISTS;
 753                         break;
 754                     }
 755                     if ((handle = lookup_handle(hp)) == 0) {
 756                         R_AH = EMS_HNAME_NOT_FOUND;
 757                     } else {
 758                         R_DX = handle;
 759                         R_AH = EMS_SUCCESS;
 760                     }
 761                     break;
 762
 763                 case GET_TOTAL_HANDLES:
 764                     R_AH = EMS_SUCCESS;
 765                     R_BX = EMS_NUM_HANDLES;     /* Includes OS handle */
 766                     break;
 767
 768                 default:
 769                     R_AH = EMS_FUNC_NOSUP;
 770                     break;
 771             }
 772             break;
 773         }
 774
 775
 776         /* I do not know if we need this. LINUX emulation leaves it out
 777          * so I leave it out too for now.
 778          */
 779         case ALTER_PAGEMAP_JUMP:
 780             debug(D_ALWAYS, "Alter pagemap and jump used!\n");
 781             R_AH = EMS_FUNC_NOSUP;
 782             break;
 783         case ALTER_PAGEMAP_CALL:
 784             debug(D_ALWAYS, "Alter pagemap and call used!\n");
 785             R_AH = EMS_FUNC_NOSUP;
 786             break;
 787
 788
 789         case MOVE_MEMORY_REGION:
 790         {
 791             EMSmovemem *emvp;
 792             u_long src_addr, dst_addr;
 793             u_short src_handle, dst_handle;
 794
 795             if (R_AL == EXCHANGE)
 796                 debug(D_EMS, "EMS: Exchange memory region ");
 797             else
 798                 debug(D_EMS, "EMS: Move memory region ");
 799
 800             emvp = (EMSmovemem *)get_valid_pointer(R_DS, R_SI,
 801                         sizeof(EMSmovemem));
 802             if (emvp == NULL) {
 803                 debug(D_EMS, "Invalid structure pointer\n");
 804                 R_AH = EMS_SW_MALFUNC;
 805                 break;
 806             }
 807             /* Zero length is not an error */
 808             if (emvp->length == 0) {
 809                 debug(D_EMS, "Zero length\n");
 810                 R_AH = EMS_SUCCESS;
 811                 break;
 812             }
 813             /* Some checks */
 814             if (emvp->src_type == EMS_MOVE_CONV) {
 815                 /* Conventional memory source */
 816                 src_addr = MAKEPTR(emvp->src_seg, emvp->src_offset);
 817                 /* May not exceed conventional memory */
 818                 if ((src_addr + emvp->length) > 640 * 1024) {
 819                     R_AH = EMS_SW_MALFUNC;
 820                     break;
 821                 }
 822             } else {
 823                 /* Check the handle */
 824                 src_handle = emvp->src_handle;
 825                 if (src_handle > 255 || src_handle == 0 ||
 826                         ems_handle[src_handle] == NULL) {
 827                     R_AH = EMS_INV_HANDLE;
 828                     debug(D_EMS, "invalid source handle\n");
 829                     break;
 830                 }
 831                 /* Offset may not exceed page size */
 832                 if (emvp->src_offset >= (16 * 1024)) {
 833                     R_AH = EMS_PAGEOFFSET;
 834                     debug(D_EMS, "source page offset too big\n");
 835                     break;
 836                 }
 837             }
 838
 839             if (emvp->dst_type == EMS_MOVE_CONV) {
 840                 /* Conventional memory source */
 841                 dst_addr = MAKEPTR(emvp->dst_seg, emvp->dst_offset);
 842                 /* May not exceed conventional memory */
 843                 if ((dst_addr + emvp->length) > 640 * 1024) {
 844                     R_AH = EMS_SW_MALFUNC;
 845                     break;
 846                 }
 847             } else {
 848                 /* Check the handle */
 849                 dst_handle = emvp->dst_handle;
 850                 if (dst_handle > 255 || dst_handle == 0 ||
 851                         ems_handle[dst_handle] == NULL) {
 852                     R_AH = EMS_INV_HANDLE;
 853                     debug(D_EMS, "invalid destination handle\n");
 854                     break;
 855                 }
 856                 /* Offset may not exceed page size */
 857                 if (emvp->dst_offset >= (16 * 1024)) {
 858                     R_AH = EMS_PAGEOFFSET;
 859                     debug(D_EMS, "destination page offset too big\n");
 860                     break;
 861                 }
 862             }
 863
 864             if (R_AL == MOVE) {
 865                 /* If it is conventional memory only, do it */
 866                 if (emvp->src_type == EMS_MOVE_CONV &&
 867                     emvp->dst_type == EMS_MOVE_CONV) {
 868                     memmove((void *)dst_addr, (void *)src_addr,
 869                         (size_t) emvp->length);
 870                     debug(D_EMS, "conventional to conventional memory done\n");
 871                     R_AH = EMS_SUCCESS;
 872                     break;
 873                 }
 874                 if (emvp->src_type == EMS_MOVE_EMS &&
 875                     emvp->dst_type == EMS_MOVE_CONV)
 876                     R_AH = move_ems_to_conv(src_handle, emvp->src_seg,
 877                         emvp->src_offset, dst_addr, emvp->length);
 878                 else if (emvp->src_type == EMS_MOVE_CONV &&
 879                     emvp->dst_type == EMS_MOVE_EMS)
 880                     R_AH = move_conv_to_ems(src_addr, dst_handle,
 881                               emvp->dst_seg, emvp->dst_offset, emvp->length);
 882                 else
 883                     R_AH = move_ems_to_ems(src_handle, emvp->src_seg,
 884                         emvp->src_offset, dst_handle, emvp->dst_seg,
 885                         emvp->dst_offset, emvp->length);
 886                 debug(D_EMS, " done\n");
 887                 break;
 888             } else {
 889                 /* exchange memory region */
 890
 891                 /* We need a scratch area for the exchange */
 892                 void *buffer;
 893                 if ((buffer = malloc(emvp->length)) == NULL)
 894                     fatal("EMS: Could not malloc scratch area for exchange");
 895
 896                 /* If it is conventional memory only, do it */
 897                 if (emvp->src_type == EMS_MOVE_CONV &&
 898                     emvp->dst_type == EMS_MOVE_CONV) {
 899                     /* destination -> buffer */
 900                     memmove(buffer, (void *)dst_addr, (size_t) emvp->length);
 901                     /* Source -> destination */
 902                     memmove((void *)dst_addr, (void *)src_addr,
 903                         (size_t) emvp->length);
 904                     /* Buffer -> source */
 905                     memmove((void *)src_addr, buffer, (size_t) emvp->length);
 906                     free(buffer);
 907                     debug(D_EMS, "conventional to conventional memory done\n");
 908                     R_AH = EMS_SUCCESS;
 909                     break;
 910                 }
 911
 912                 /* Exchange EMS with conventional */
 913                 if (emvp->src_type == EMS_MOVE_EMS &&
 914                     emvp->dst_type == EMS_MOVE_CONV) {
 915                     /* Destination -> buffer */
 916                     memmove(buffer, (void *)dst_addr, (size_t) emvp->length);
 917                     /* Source -> destination */
 918                     R_AH = move_ems_to_conv(src_handle, emvp->src_seg,
 919                               emvp->src_offset, dst_addr, emvp->length);
 920                     if (R_AH != EMS_SUCCESS) {
 921                         free(buffer);
 922                         break;
 923                     }
 924                     /* Buffer -> source */
 925                     R_AH = move_conv_to_ems((u_long)buffer, src_handle,
 926                               emvp->src_seg, emvp->src_offset, emvp->length);
 927
 928                 /* Exchange conventional with EMS */
 929                 } else if (emvp->src_type == EMS_MOVE_CONV &&
 930                            emvp->dst_type == EMS_MOVE_EMS) {
 931                     /* Destination -> buffer */
 932                     R_AH = move_ems_to_conv(dst_handle, emvp->dst_seg,
 933                         emvp->dst_offset, (u_long)buffer, emvp->length);
 934                     if (R_AH != EMS_SUCCESS) {
 935                         free(buffer);
 936                         break;
 937                     }
 938                     /* Source -> destination */
 939                     R_AH = move_conv_to_ems((u_long)buffer, dst_handle,
 940                               emvp->dst_seg, emvp->dst_offset, emvp->length);
 941                     /* Buffer -> source */
 942                     memmove(buffer, (void *)src_addr, (size_t) emvp->length);
 943
 944                 /* Exchange EMS with EMS */
 945                 } else {
 946                     /* Destination -> buffer */
 947                     R_AH = move_ems_to_conv(dst_handle, emvp->dst_seg,
 948                         emvp->dst_offset, (u_long)buffer, emvp->length);
 949                     if (R_AH != EMS_SUCCESS) {
 950                         free(buffer);
 951                         break;
 952                     }
 953                     /* Source -> destination */
 954                     R_AH = move_ems_to_ems(src_handle, emvp->src_seg,
 955                         emvp->src_offset, dst_handle, emvp->dst_seg,
 956                         emvp->dst_offset, emvp->length);
 957                     if (R_AH != EMS_SUCCESS) {
 958                         free(buffer);
 959                         break;
 960                     }
 961                     /* Buffer -> source */
 962                     R_AH = move_conv_to_ems((u_long)buffer, src_handle,
 963                               emvp->src_seg, emvp->src_offset, emvp->length);
 964                 }
 965                 free(buffer);
 966             }
 967             debug(D_EMS, " done\n");
 968             break;
 969         }
 970
 971         case GET_MAPPABLE_PHYS_ADDR:
 972         {
 973             switch (R_AL) {
 974                 case GET_ARRAY:
 975                 {
 976                     EMSaddrarray *eadp;
 977                     int i;
 978                     u_short seg;
 979
 980                     eadp = (EMSaddrarray *)get_valid_pointer(R_ES, R_DI,
 981                         sizeof(EMSaddrarray) * 4);
 982                     if (eadp == NULL) {
 983                         R_AH = EMS_SW_MALFUNC;
 984                         break;
 985                     }
 986                     for (i = 0, seg = (ems_frame_addr >> 4); i < 4; i++) {
 987                         eadp->segm = seg;
 988                         eadp->phys = i;
 989                         eadp++;
 990                         seg += 1024;
 991                     }
 992                     R_AH = EMS_SUCCESS;
 993                     break;
 994                 }
 995                 case GET_ARRAY_ENTRIES:
 996                     /* There are always 4 positions, 4*16kB = 64kB */
 997                     R_CX = 4;
 998                     R_AH = EMS_SUCCESS;
 999                     break;
1000                 default:
1001                     R_AH = EMS_FUNC_NOSUP;
1002                     break;
1003             }
1004             break;
1005         }
1006
1007         /* This is an OS function in the LIM EMS 4.0 standard: It is
1008          * usable only by an OS and its use can be disabled for all other
1009          * programs. I think we do not need to support it. It is not
1010          * implemented and it reports "disabled" to any caller.
1011          */
1012         case GET_HW_CONFIGURATION:
1013             R_AH = EMS_FUNCTION_DISABLED;
1014             break;
1015
1016         /* This function is a little different, it was defined with
1017          * LIM EMS 4.0: It is allowed to allocate zero pages and raw
1018          * page size (i.e. page size != 16kB) is supported. We have
1019          * only 16kB pages, so the second difference does not matter.
1020          */
1021         case ALLOCATE_PAGES:
1022         {
1023             u_short npages;
1024             short handle;
1025
1026             npages = R_BX;
1027             debug(D_EMS, "EMS: Get handle and allocate %d pages: ", npages);
1028
1029             /* Enough handles? */
1030             if ((handle = find_next_free_handle()) < 0) {
1031                 debug(D_EMS,"Return error:No handles\n");
1032                 R_AH = EMS_OUT_OF_HANDLES;
1033                 break;
1034             }
1035             /* Enough memory for this request ? */
1036             if (npages > ems_free_pages) {
1037                 debug(D_EMS,"Return error:Request too big\n");
1038                 R_AH = EMS_OUT_OF_LOG;
1039                 break;
1040             }
1041             if (npages > ems_total_pages) {
1042                 debug(D_EMS,"Return error:Request too big\n");
1043                 R_AH = EMS_OUT_OF_PHYS;
1044                 break;
1045             }
1046
1047             /* Allocate the handle */
1048             allocate_handle(handle, npages);
1049
1050             /* Allocate the pages */
1051             allocate_pages_to_handle(handle, npages);
1052             R_DX = handle;
1053             R_AH = EMS_SUCCESS;
1054             debug(D_EMS,"Return success:Handle = %d\n", handle);
1055             break;
1056         }
1057
1058         /* This is an OS function in the LIM EMS 4.0 standard: It is
1059          * usable only by an OS and its use can be disabled for all other
1060          * programs. I think we do not need to support it. It is not
1061          * implemented and it reports "disabled" to any caller.
1062          */
1063         case ALTERNATE_MAP_REGISTER:
1064             R_AH = EMS_FUNCTION_DISABLED;
1065             break;
1066
1067         /* We cannot support that ! */
1068         case PREPARE_WARMBOOT:
1069             R_AH = EMS_FUNC_NOSUP;
1070             break;
1071
1072         case OS_FUNCTION_SET:
1073             R_AH = EMS_FUNCTION_DISABLED;
1074             break;
1075
1076         default:
1077             debug(D_ALWAYS, "EMS: Unknown function called: %02x\n", R_AH);
1078             R_AH = EMS_FUNC_NOSUP;
1079             break;
1080     }
1081 }
1082
1083 /* Initialize the EMS memory: Return 1 on success, 0 on failure */
1084
1085 static int
1086 init_mapfile(void)
1087 {
1088     char path[256];
1089     int mfd;
1090
1091     /* Sanity */
1092     if (ems_max_size == 0)
1093         return 0;
1094     strcpy(path, EMS_MAP_PATH);
1095     strcat(path, EMS_MAP_FILE);
1096
1097     mfd = mkstemp(path);
1098
1099     if (mfd < 0) {
1100         debug(D_ALWAYS, "Could not create EMS mapfile, ");
1101         goto fail;
1102     }
1103     unlink(path);
1104     mapfile_fd = squirrel_fd(mfd);
1105
1106     if (lseek(mapfile_fd, (off_t)(ems_max_size - 1), 0) < 0) {
1107         debug(D_ALWAYS, "Could not seek into EMS mapfile, ");
1108         goto fail;
1109     }
1110     if (write(mapfile_fd, "", 1) < 0) {
1111         debug(D_ALWAYS, "Could not write to EMS mapfile, ");
1112         goto fail;
1113     }
1114     /* Unmap the entire page frame */
1115     if (munmap((caddr_t)ems_frame_addr, 64 * 1024) < 0) {
1116         debug(D_ALWAYS, "Could not unmap EMS page frame, ");
1117         goto fail;
1118     }
1119     /* DOS programs will access the page frame without allocating
1120      * pages first. Microsoft diagnose MSD.EXE does this, for example
1121      * We need to have memory here to avoid segmentation violation
1122      */
1123     if (mmap((caddr_t)ems_frame_addr, 64 * 1024,
1124               PROT_EXEC | PROT_READ | PROT_WRITE,
1125               MAP_ANON | MAP_FIXED | MAP_SHARED,
1126               -1, 0) == MAP_FAILED) {
1127         debug(D_ALWAYS, "Could not map EMS page frame, ");
1128         goto fail;
1129     }
1130     bzero((void *)&ems_mapping_context, sizeof(EMS_mapping_context));
1131     return (1);
1132
1133 fail:
1134     debug(D_ALWAYS, "EMS disabled\n");
1135     ems_max_size = 0;
1136     ems_frame_addr = 0;
1137     return (0);
1138 }
1139
1140 /* Map/Unmap pages into one of four positions in the frame segment */
1141
1142 static void
1143 map_page(u_long pagenum, u_char position, short handle, int unmaponly)
1144 {
1145     caddr_t map_addr;
1146     size_t  len;
1147     off_t   file_offs;
1148
1149     if (position > 3)
1150         fatal("EMS: Internal error: Mapping position\n");
1151
1152     map_addr = (caddr_t)(ems_frame_addr + (1024 * 16 * (u_long)position));
1153     len = 1024 * 16;
1154     file_offs = (off_t)(pagenum * 16 * 1024);
1155
1156     if (ems_mapping_context.pos_mapped[position]) {
1157         if (munmap(map_addr, len) < 0) {
1158              fatal("EMS unmapping error: %s\nCannot recover\n",
1159                 strerror(errno));
1160         }
1161         ems_page[ems_mapping_context.pos_pagenum[position]].status
1162                 &= ~EMS_MAPPED;
1163         ems_mapping_context.pos_mapped[position] = 0;
1164         ems_mapping_context.handle[position] = 0;
1165     }
1166     if (unmaponly) {
1167         /* DOS programs will access the page frame without allocating
1168          * pages first. Microsoft diagnose MSD.EXE does this, for example
1169          * We need to have memory here to avoid segmentation violation
1170          */
1171         if (mmap((caddr_t)ems_frame_addr, 64 * 1024,
1172               PROT_EXEC | PROT_READ | PROT_WRITE,
1173               MAP_ANON | MAP_FIXED | MAP_SHARED,
1174               -1, 0) == MAP_FAILED)
1175             fatal("Could not map EMS page frame during unmap only\n");
1176         return;
1177     }
1178     if (mmap(map_addr, len,
1179               PROT_EXEC | PROT_READ | PROT_WRITE,
1180               MAP_FILE | MAP_FIXED | MAP_SHARED,
1181               mapfile_fd, file_offs) == MAP_FAILED) {
1182         fatal("EMS mapping error: %s\nCannot recover\n", strerror(errno));
1183     }
1184     ems_mapping_context.pos_mapped[position] = 1;
1185     ems_mapping_context.pos_pagenum[position] = pagenum;
1186     ems_mapping_context.handle[position] = handle;
1187     ems_page[pagenum].status |= EMS_MAPPED;
1188 }
1189
1190 /* Get a pointer from VM86 app, check it and return it. This returns NULL
1191  * if the pointer is not valid. We can check only for very limited
1192  * criteria: The pointer and the area defined by size may not point to
1193  * memory over 1MB and it may not may to addresses under 1kB, because there
1194  * is the VM86 interrupt table.
1195  */
1196 static void *
1197 get_valid_pointer(u_short seg, u_short offs, u_long size)
1198 {
1199     u_long addr;
1200     addr = MAKEPTR(seg, offs);
1201     /* Check bounds */
1202     if ((addr + size) >= (1024 * 1024) || addr < 1024)
1203         return NULL;
1204     else
1205         return (void *)addr;
1206 }
1207
1208 /* Malloc a new handle */
1209 static EMS_handle *
1210 get_new_handle(long npages)
1211 {
1212     EMS_handle *ehp;
1213     size_t dynsize = sizeof(EMS_handle) + sizeof(short) * npages;
1214
1215     if ((ehp = calloc(1, dynsize)) == NULL)
1216         fatal("Cannot malloc EMS handle, cannot continue\n");
1217     return ehp;
1218 }
1219
1220 /* Allocate a mapping context to a handle */
1221 static void
1222 context_to_handle(short handle)
1223 {
1224     EMS_mapping_context *emc;
1225
1226     if (ems_handle[handle] == NULL)
1227         fatal("EMS context_to_handle called with invalid handle\n");
1228     if ((emc = calloc(1, sizeof(EMS_mapping_context))) == NULL)
1229         fatal("EMS Cannot malloc mapping context, cannot continue\n");
1230     ems_handle[handle]->mcontext = emc;
1231     memmove((void *)emc, (void *)&ems_mapping_context,
1232              sizeof(EMS_mapping_context));
1233 }
1234
1235 /* Find the next free handle, returns -1 if there are no more handles */
1236 static long
1237 find_next_free_handle(void)
1238 {
1239     int i;
1240
1241     if (ems_alloc_handles >= 255)
1242         return (-1);
1243     /* handle 0 is OS handle */
1244     for (i = 1; i < EMS_NUM_HANDLES; i++) {
1245         if (ems_handle[i] == NULL)
1246             return (i);
1247     }
1248     fatal("EMS handle count garbled, should not happen\n");
1249     /* quiet 'gcc -Wall' */
1250     return (-1);
1251 }
1252
1253 /* Look for a named handle, returns 0 if not found, else handle */
1254 static short
1255 lookup_handle(Hname *hp)
1256 {
1257     int i;
1258
1259     for (i = 1; i < EMS_NUM_HANDLES; i++) {
1260         if (ems_handle[i] != NULL) {
1261             if (hp->ul_hn[0] == ems_handle[i]->hname.ul_hn[0] &&
1262                 hp->ul_hn[1] == ems_handle[i]->hname.ul_hn[1])
1263                 return (i);
1264         }
1265     }
1266     return (0);
1267 }
1268
1269 /* Malloc a new handle struct and put into array at index handle */
1270 static void
1271 allocate_handle(short handle, long npages)
1272 {
1273     if (ems_handle[handle] != NULL)
1274         fatal("EMS allocate_handle, handle was not free\n");
1275     ems_handle[handle] = get_new_handle(npages);
1276     ems_alloc_handles++;
1277 }
1278
1279 /* Free a handle, return its memory. Call this *after* freeing the
1280  * allocated pages !
1281  */
1282 static void
1283 free_handle(short handle)
1284 {
1285     if (ems_handle[handle] == NULL)
1286         fatal("EMS free_handle, handle was free\n");
1287     if (ems_handle[handle]->mcontext != NULL)
1288         free((void *)ems_handle[handle]->mcontext);
1289     free((void *)ems_handle[handle]);
1290     ems_handle[handle] = NULL;
1291     ems_alloc_handles--;
1292 }
1293
1294
1295 /* Allocates npages to handle. Call this routine only after you have
1296  * ensured there are enough free pages *and* the new handle is in place
1297  * in the handle array !
1298  */
1299 static void
1300 allocate_pages_to_handle(u_short handle, long npages)
1301 {
1302     unsigned syspagenum;
1303     int pages_to_alloc = npages;
1304     int allocpagenum = 0;
1305
1306     /* sanity */
1307     if (handle > 255 || ems_handle[handle] == NULL)
1308         fatal("EMS allocate_pages_to_handle called with invalid handle\n");
1309
1310     ems_handle[handle]->npages = npages;
1311     for (syspagenum = 0; syspagenum < ems_total_pages; syspagenum++) {
1312         if (ems_page[syspagenum].status == EMS_FREE) {
1313             ems_page[syspagenum].handle = handle;
1314             ems_page[syspagenum].status = EMS_ALLOCED;
1315             ems_handle[handle]->pagenum[allocpagenum] = syspagenum;
1316             allocpagenum++;
1317             pages_to_alloc--;
1318             if (pages_to_alloc == 0)
1319                 break;
1320         }
1321     }
1322     if (pages_to_alloc > 0)
1323         fatal("EMS allocate_pages_to_handle found not enough free pages\n");
1324     ems_alloc_pages += npages;
1325     ems_free_pages -= npages;
1326 }
1327
1328 /* Reallocates npages to handle. Call this routine only after you have
1329  * ensured there are enough free pages *and* the new handle is in place
1330  * in the handle array !
1331  */
1332 static void
1333 reallocate_pages_to_handle(u_short handle, long npages)
1334 {
1335     unsigned allocpagenum;
1336     unsigned syspagenum;
1337     int pages_to_alloc;
1338     long delta;
1339     size_t dynsize;
1340     EMS_handle *emp;
1341
1342     /* sanity */
1343     if (handle > 255 || ems_handle[handle] == NULL)
1344         fatal("EMS allocate_pages_to_handle called with invalid handle\n");
1345
1346     delta = npages - ems_handle[handle]->npages;
1347     if (delta > 0) {
1348         /* Grow array size and allocation */
1349
1350         emp = ems_handle[handle];
1351         dynsize = sizeof(EMS_handle) + sizeof(short) * npages;
1352
1353         /* First step: Make room in the handle pagenum array */
1354         if ((emp = (EMS_handle *)realloc((void *)emp, dynsize)) == NULL)
1355             fatal("Cannot malloc EMS handle, cannot continue\n");
1356         ems_handle[handle] = emp;
1357
1358         /* Second step: Add pages to the handle */
1359         pages_to_alloc = delta;
1360         allocpagenum = ems_handle[handle]->npages;
1361         ems_handle[handle]->npages = npages;
1362         for (syspagenum = 0; syspagenum < ems_total_pages; syspagenum++) {
1363             if (ems_page[syspagenum].status == EMS_FREE) {
1364                 ems_page[syspagenum].handle = handle;
1365                 ems_page[syspagenum].status = EMS_ALLOCED;
1366                 ems_handle[handle]->pagenum[allocpagenum] = syspagenum;
1367                 allocpagenum++;
1368                 pages_to_alloc--;
1369                 if (pages_to_alloc == 0)
1370                     break;
1371             }
1372         }
1373         if (pages_to_alloc > 0)
1374             fatal("EMS allocate_pages_to_handle found not enough free pages\n");
1375
1376     } else {
1377         /* Shrink array size and allocation */
1378
1379         /* First step: Deallocate all pages from new size to old size */
1380         for (allocpagenum = npages;
1381                 allocpagenum < ems_handle[handle]->npages;
1382                 allocpagenum++) {
1383             syspagenum = ems_handle[handle]->pagenum[allocpagenum];
1384
1385             /* sanity */
1386             if (syspagenum > ems_total_pages)
1387                 fatal("EMS free_pages_of_handle found invalid page number\n");
1388             if (!(ems_page[syspagenum].status & EMS_ALLOCED))
1389                 fatal("EMS free_pages_of_handle tried to free page already free\n");
1390             ems_page[syspagenum].handle = 0;
1391             ems_page[syspagenum].status = EMS_FREE;
1392         }
1393
1394         /* Second step: Shrink the dynamic array of the handle */
1395         dynsize = sizeof(EMS_handle) + sizeof(short) * npages;
1396         emp = ems_handle[handle];
1397         if ((emp = (EMS_handle *)realloc((void *)emp, dynsize)) == NULL)
1398             fatal("Cannot realloc EMS handle, cannot continue\n");
1399         ems_handle[handle] = emp;
1400         ems_handle[handle]->npages = npages;
1401     }
1402     ems_alloc_pages += delta;
1403     ems_free_pages -= delta;
1404 }
1405
1406 /* Free all pages belonging to a handle, handle must be valid */
1407 static void
1408 free_pages_of_handle(short handle)
1409 {
1410     int allocpagenum;
1411     unsigned syspagenum;
1412     int npages;
1413
1414     /* sanity */
1415
1416     if (handle > 255 || ems_handle[handle] == NULL)
1417         fatal("EMS free_pages_of_handle called with invalid handle\n");
1418
1419     if ((npages = ems_handle[handle]->npages) == 0)
1420         return;
1421
1422     for (allocpagenum = 0; allocpagenum < npages; allocpagenum++) {
1423         syspagenum = ems_handle[handle]->pagenum[allocpagenum];
1424         /* sanity */
1425         if (syspagenum > ems_total_pages)
1426             fatal("EMS free_pages_of_handle found invalid page number\n");
1427         if (!(ems_page[syspagenum].status & EMS_ALLOCED))
1428             fatal("EMS free_pages_of_handle tried to free page already free\n");
1429         ems_page[syspagenum].handle = 0;
1430         ems_page[syspagenum].status = EMS_FREE;
1431     }
1432     ems_alloc_pages -= npages;
1433     ems_free_pages += npages;
1434 }
1435
1436 /* Restore a saved mapping context, overwrites current mapping context */
1437 static void
1438 restore_context(EMS_mapping_context *emc)
1439 {
1440     int i;
1441
1442     for (i = 0; i < 4; i++) {
1443         ems_mapping_context.handle[i] = emc->handle[i];
1444         if (emc->pos_mapped[i] != 0 &&
1445             ems_mapping_context.pos_pagenum[i] != emc->pos_pagenum[i]) {
1446             map_page(emc->pos_pagenum[i], (u_char) i, emc->handle[i], 0);
1447         } else {
1448             ems_mapping_context.pos_mapped[i] = 0;
1449         }
1450     }
1451 }
1452
1453 /* Prepare a special context save block for DOS and save it to
1454  * VM86 memory
1455  */
1456 static void
1457 save_context_to_dos(EMScontext *emp)
1458 {
1459     int i, end;
1460     EMScontext context;
1461     u_short *sp;
1462     u_short sum;
1463
1464     context.ems_saved_context = ems_mapping_context;
1465     context.magic = EMS_SAVEMAGIC;
1466     context.checksum = 0;
1467     sp = (u_short *)&context;
1468     end = sizeof(EMScontext) / sizeof(short);
1469     /* Generate checksum */
1470     for (i = 0, sum = 0; i < end; i++) {
1471         sum += *sp++;
1472         sum &= 0xffff;
1473     }
1474     context.checksum = 0x10000L - sum;
1475     /* Save it to VM86 memory */
1476     *emp = context;
1477 }
1478
1479 /* Check a context returned from VM86 app for validity, return 0, if
1480  * not valid, else return 1
1481  */
1482 static int
1483 check_saved_context(EMScontext *emp)
1484 {
1485     int i, end;
1486     u_short *sp;
1487     u_short sum;
1488
1489     if (emp->magic != EMS_SAVEMAGIC)
1490         return 0;
1491
1492     sp = (u_short *)emp;
1493     end = sizeof(EMScontext) / sizeof(short);
1494     /* Generate checksum */
1495     for (i = 0, sum = 0; i < end; i++) {
1496         sum += *sp++;
1497         sum &= 0xffff;
1498     }
1499     if (sum != 0)
1500         return 0;
1501     else
1502         return 1;
1503 }
1504
1505 /* Helper routine for the move routines below: Check if length bytes
1506  * can be moved from/to handle pages (i.e are there enough pages)
1507  */
1508 static int
1509 check_alloc_pages(u_short handle, u_short firstpage, u_short offset,
1510                   u_long length __unused)
1511 {
1512     u_long nbytes;
1513
1514     if (firstpage > ems_handle[handle]->npages)
1515         return (0);
1516     nbytes = (ems_handle[handle]->npages - firstpage) * EMS_PAGESIZE - offset;
1517     return (ems_handle[handle]->npages >= nbytes);
1518 }
1519
1520 /* Copy a block of memory up to the next 16kB boundary in the source
1521  * to the destination in upward direction (i.e. with ascending addresses)
1522  * XXX Could be an inline function.
1523  */
1524 static void
1525 copy_block_up(struct copydesc *cdp)
1526 {
1527     size_t size;
1528     void *srcp;
1529     void *dstp;
1530
1531     /* If source or both memory types are EMS, source determines the
1532      * block lenght, else destination determines the block lenght
1533      */
1534     if (cdp->copytype & SRC_EMS)
1535         size = EMS_PAGESIZE - cdp->EMS_OFFS(src_addr);
1536     else
1537         size = EMS_PAGESIZE - cdp->EMS_OFFS(dst_addr);
1538
1539     if (size > cdp->rest_len)
1540         size = cdp->rest_len;
1541
1542     /* If src is EMS memory, it is mapped into position 0 */
1543     if (cdp->copytype & SRC_EMS)
1544         srcp = (void *)(ems_frame_addr + cdp->EMS_OFFS(src_addr));
1545     else
1546         srcp = (void *)(cdp->EMS_PTR(src_addr));
1547
1548     /* If dest is EMS memory, it is mapped into position 1,2 */
1549     if (cdp->copytype & DST_EMS)
1550         dstp = (void *)(ems_frame_addr + EMS_PAGESIZE +
1551                                         cdp->EMS_OFFS(dst_addr));
1552     else
1553         dstp = (void *)(cdp->EMS_PTR(dst_addr));
1554
1555     /* Move this block */
1556     memmove(dstp, srcp, size);
1557
1558     /* Update the copy descriptor: This updates the address of both
1559      * conventional and EMS memory
1560      */
1561     cdp->EMS_PTR(src_addr) += size;
1562     cdp->EMS_PTR(dst_addr) += size;
1563
1564     cdp->rest_len -= size;
1565 }
1566
1567
1568 /* Move EMS memory starting with handle page src_seg and offset src_offset
1569  * to conventional memory dst_addr for length bytes
1570  * dst_addr is checked, handle is valid
1571  */
1572 static u_long
1573 move_ems_to_conv(short src_handle, u_short src_seg,
1574                         u_short src_offset, u_long dst_addr, u_long length)
1575 {
1576     EMS_mapping_context ems_saved_context;
1577     EMS_handle *ehp;
1578     int pageindx = src_seg;
1579     struct copydesc cd;
1580
1581     if (check_alloc_pages(src_handle, src_seg, src_offset, length) == 0)
1582         return EMS_MOVE_OVERFLOW;
1583
1584     ehp = ems_handle[src_handle];
1585
1586     /* Prepare the move: Save the mapping context */
1587     ems_saved_context = ems_mapping_context;
1588
1589     /* Setup the copy descriptor struct */
1590
1591     cd.copytype = SRC_EMS;
1592     cd.EMS_PAGE(src_addr) = ehp->pagenum[pageindx];
1593     cd.EMS_OFFS(src_addr) = src_offset;
1594     cd.EMS_PTR(dst_addr) = dst_addr;
1595     cd.rest_len = length;
1596
1597     do {
1598         /* Map for the first block copy, source is mapped to position zero */
1599         map_page(cd.EMS_PAGE(src_addr), 0, src_handle, 0);
1600         copy_block_up(&cd);
1601     } while(cd.rest_len > 0);
1602
1603     /* Restore the original mapping */
1604     restore_context(&ems_saved_context);
1605     return EMS_SUCCESS;
1606 }
1607
1608 /* Move conventional memory starting with src_addr
1609  * to EMS memory starting with handle page src_seg and offset src_offset
1610  * for length bytes
1611  * dst_addr is checked, handle is valid
1612  */
1613 static u_long
1614 move_conv_to_ems(u_long src_addr, u_short dst_handle, u_short dst_seg,
1615                  u_short dst_offset, u_long length)
1616 {
1617     EMS_mapping_context ems_saved_context;
1618     EMS_handle *ehp;
1619     int pageindx = dst_seg;
1620     struct copydesc cd;
1621
1622     if (check_alloc_pages(dst_handle, dst_seg, dst_offset, length) == 0)
1623         return EMS_MOVE_OVERFLOW;
1624
1625     ehp = ems_handle[dst_handle];
1626
1627     /* Prepare the move: Save the mapping context */
1628     ems_saved_context = ems_mapping_context;
1629
1630     /* Setup the copy descriptor struct */
1631
1632     cd.copytype = DST_EMS;
1633     cd.EMS_PAGE(dst_addr) = ehp->pagenum[pageindx];
1634     cd.EMS_OFFS(dst_addr) = dst_offset;
1635     cd.EMS_PTR(src_addr) = src_addr;
1636     cd.rest_len = length;
1637
1638     do {
1639         map_page(cd.EMS_PAGE(dst_addr), 1, dst_handle, 0);
1640         copy_block_up(&cd);
1641     } while(cd.rest_len > 0);
1642
1643     /* Restore the original mapping */
1644     restore_context(&ems_saved_context);
1645     return EMS_SUCCESS;
1646 }
1647
1648 static u_long
1649 move_ems_to_ems(u_short src_handle, u_short src_seg, u_short src_offset,
1650                 u_short dst_handle, u_short dst_seg, u_short dst_offset,
1651                 u_long length)
1652 {
1653     EMS_mapping_context ems_saved_context;
1654     EMS_handle *src_hp, *dst_hp;
1655     struct copydesc cd;
1656
1657     if (check_alloc_pages(src_handle, src_seg, src_offset, length) == 0)
1658         return EMS_MOVE_OVERFLOW;
1659     if (check_alloc_pages(dst_handle, dst_seg, dst_offset, length) == 0)
1660         return EMS_MOVE_OVERFLOW;
1661
1662     src_hp = ems_handle[src_handle];
1663     dst_hp = ems_handle[dst_handle];
1664
1665     /* Prepare the move: Save the mapping context */
1666     ems_saved_context = ems_mapping_context;
1667
1668     /* Setup the copy descriptor struct */
1669
1670     cd.copytype = SRC_EMS | DST_EMS;
1671     cd.EMS_PAGE(src_addr) = src_hp->pagenum[src_seg];
1672     cd.EMS_OFFS(src_addr) = src_offset;
1673     cd.EMS_PAGE(dst_addr) = dst_hp->pagenum[dst_seg];
1674     cd.EMS_OFFS(dst_addr) = dst_offset;
1675     cd.rest_len = length;
1676
1677     /* Copy */
1678     do {
1679         map_page(cd.EMS_PAGE(src_addr), 0, src_handle, 0);
1680         map_page(cd.EMS_PAGE(dst_addr), 1, dst_handle, 0);
1681         /* If there are more pages, map the next destination page to
1682          * position 2. This removes a compare between source and dest
1683          * offsets.
1684          */
1685         if (cd.EMS_PAGE(dst_addr) < dst_hp->npages)
1686             map_page((cd.EMS_PAGE(dst_addr) + 1), 2, dst_handle, 0);
1687         copy_block_up(&cd);
1688     } while(cd.rest_len > 0);
1689
1690     /* Restore the original mapping */
1691     restore_context(&ems_saved_context);
1692     return EMS_SUCCESS;
1693 }