outrdf2.c

   1 /* outrdf2.c    output routines for the Netwide Assembler to produce
   2  *              RDOFF version 2 format object files (which are intended
   3  *              mainly for use in proprietary projects, as the code to
   4  *              load and execute them is very simple). They will also be
   5  *              used for device drivers and possibly some executable files
   6  *              in the MOSCOW operating system. See Rdoff.txt for
   7  *              details.
   8  *
   9  * The Netwide Assembler is copyright (C) 1996-1998 Simon Tatham and
  10  * Julian Hall. All rights reserved. The software is
  11  * redistributable under the licence given in the file "Licence"
  12  * distributed in the NASM archive.
  13  */
  14
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <ctype.h>
  19 #include <assert.h>
  20
  21 #include "nasm.h"
  22 #include "nasmlib.h"
  23 #include "outform.h"
  24
  25 /* VERBOSE_WARNINGS: define this to add some extra warnings... */
  26 #define VERBOSE_WARNINGS
  27
  28 #ifdef OF_RDF2
  29
  30 #define RDF_MAXSEGS 64  /* maximum number of segments - user configurable */
  31
  32 typedef unsigned short int16;
  33 typedef unsigned char byte;
  34
  35 static const char *RDOFF2Id = "RDOFF2"; /* written to start of RDOFF files */
  36
  37
  38 /* the records that can be found in the RDOFF header */
  39
  40 /* Note that whenever a segment is referred to in the RDOFF file, its number
  41  * is always half of the segment number that NASM uses to refer to it; this
  42  * is because NASM only allocates even numbered segments, so as to not
  43  * waste any of the 16 bits of segment number written to the file - this
  44  * allows up to 65533 external labels to be defined; otherwise it would be
  45  * 32764. */
  46
  47 struct RelocRec {
  48   byte  type;           /* must be 1, or 6 for segment base ref */
  49   byte  reclen;         /* set to 8 */
  50   byte  segment;        /* only 0 for code, or 1 for data supported,
  51                          * but add 64 for relative refs (ie do not require
  52                          * reloc @ loadtime, only linkage) */
  53   long  offset;         /* from start of segment in which reference is loc'd */
  54   byte  length;         /* 1 2 or 4 bytes */
  55   int16 refseg;         /* segment to which reference refers to */
  56 };
  57
  58 struct ImportRec {
  59   byte  type;           /* must be 2, or 7 for FAR import */
  60   byte  reclen;         /* equals 3+label length */
  61   int16 segment;        /* segment number allocated to the label for reloc
  62                          * records - label is assumed to be at offset zero
  63                          * in this segment, so linker must fix up with offset
  64                          * of segment and of offset within segment */
  65   char  label[33];      /* zero terminated... should be written to file until
  66                          * the zero, but not after it - max len = 32 chars */
  67 };
  68
  69 struct ExportRec {
  70   byte  type;           /* must be 3 */
  71   byte  reclen;         /* equals 6+label length */
  72   byte  segment;        /* segment referred to (0/1) */
  73   long  offset;         /* offset within segment */
  74   char  label[33];      /* zero terminated as above. max len = 32 chars */
  75 };
  76
  77 struct DLLRec {
  78   byte  type;           /* must be 4 */
  79   byte  reclen;         /* equals 1+library name */
  80   char  libname[128];   /* name of library to link with at load time */
  81 };
  82
  83 struct BSSRec {
  84   byte  type;           /* must be 5 */
  85   byte  reclen;         /* equeals 4 */
  86   long  amount;         /* number of bytes BSS to reserve */
  87 };
  88
  89 #define COUNT_SEGTYPES 9
  90
  91 static char * segmenttypes[COUNT_SEGTYPES] = {
  92   "null", "text", "code", "data", "comment", "lcomment", "pcomment",
  93   "symdebug", "linedebug"
  94 };
  95
  96 static int segmenttypenumbers[COUNT_SEGTYPES] = {
  97   0, 1, 1, 2, 3, 4, 5, 6, 7
  98 };
  99
 100 /* code for managing buffers needed to seperate code and data into individual
 101  * sections until they are ready to be written to the file.
 102  * We'd better hope that it all fits in memory else we're buggered... */
 103
 104 #define BUF_BLOCK_LEN 4088              /* selected to match page size (4096)
 105                                          * on 80x86 machines for efficiency */
 106
 107 /***********************************************************************
 108  * Actual code to deal with RDOFF2 ouput format begins here...
 109  */
 110
 111 /* global variables set during the initialisation phase */
 112
 113 static struct SAA *seg[RDF_MAXSEGS];    /* seg 0 = code, seg 1 = data */
 114 static struct SAA *header;      /* relocation/import/export records */
 115
 116 static FILE *ofile;
 117
 118 static efunc error;
 119
 120 static struct seginfo {
 121   char *segname;
 122   int   segnumber;
 123   int16 segtype;
 124   int16 segreserved;
 125   long  seglength;
 126 } segments[RDF_MAXSEGS];
 127
 128 static int nsegments;
 129
 130 static long bsslength;
 131 static long headerlength;
 132
 133 static void rdf2_init(FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval)
 134 {
 135   int segtext, segdata, segbss;
 136
 137   /* set up the initial segments */
 138   segments[0].segname = ".text";
 139   segments[0].segnumber = 0;
 140   segments[0].segtype = 1;
 141   segments[0].segreserved = 0;
 142   segments[0].seglength = 0;
 143
 144   segments[1].segname = ".data";
 145   segments[1].segnumber = 1;
 146   segments[1].segtype = 2;
 147   segments[1].segreserved = 0;
 148   segments[1].seglength = 0;
 149
 150   segments[2].segname = ".bss";
 151   segments[2].segnumber = 2;
 152   segments[2].segtype = 0xFFFF; /* reserved - should never be produced */
 153   segments[2].segreserved = 0;
 154   segments[2].seglength = 0;
 155
 156   nsegments = 3;
 157
 158   ofile = fp;
 159   error = errfunc;
 160
 161   seg[0] = saa_init(1L);
 162   seg[1] = saa_init(1L);
 163   seg[2] = NULL;                /* special case! */
 164
 165   header = saa_init(1L);
 166
 167   segtext = seg_alloc();
 168   segdata = seg_alloc();
 169   segbss = seg_alloc();
 170   if (segtext != 0 || segdata != 2 || segbss != 4)
 171     error(ERR_PANIC,"rdf segment numbers not allocated as expected (%d,%d,%d)",
 172           segtext,segdata,segbss);
 173   bsslength=0;
 174   headerlength = 0;
 175 }
 176
 177 static long rdf2_section_names(char *name, int pass, int *bits)
 178 {
 179   int   i;
 180   char  * p, * q;
 181   int   code = -1;
 182   int   reserved = 0;
 183
 184   /*
 185    * Default is 32 bits, in the text segment.
 186    */
 187   if (!name) {
 188     *bits = 32;
 189     return 0;
 190   }
 191
 192   /* look for segment type code following segment name */
 193   p = name;
 194   while (*p && !isspace(*p)) p++;
 195   if (*p) {     /* we're now in whitespace */
 196     *p++ = '\0';
 197     while (*p && isspace(80)) *p++ = '\0';
 198   }
 199   if (*p) {     /* we're now in an attribute value */
 200     /*
 201      * see if we have an optional ',number' following the type code
 202      */
 203     if ((q = strchr(p, ',')) != NULL) {
 204       *q++ = '\0';
 205
 206       reserved = readnum(q, &i);
 207       if (i) {
 208           error(ERR_NONFATAL, "value following comma must be numeric");
 209           reserved = 0;
 210       }
 211     }
 212     /*
 213      * check it against the text strings in segmenttypes
 214      */
 215
 216     for (i = 0; i < COUNT_SEGTYPES; i++)
 217       if (!nasm_stricmp(p, segmenttypes[i])) {
 218         code = segmenttypenumbers[i];
 219         break;
 220       }
 221     if (code == -1) {   /* didn't find anything */
 222       code = readnum(p, &i);
 223       if (i) {
 224         error(ERR_NONFATAL, "unrecognised RDF segment type (%s)",p);
 225         code = 3;
 226       }
 227     }
 228   }
 229   for (i = 0; i < nsegments; i++) {
 230     if (!strcmp(name, segments[i].segname)) {
 231       if (code != -1 || reserved != 0)
 232         error(ERR_NONFATAL, "segment attributes specified on"
 233               " redeclaration of segment");
 234       return segments[i].segnumber * 2;
 235     }
 236   }
 237
 238   /* declaring a new segment! */
 239
 240   if (code == -1) {
 241     error(ERR_NONFATAL, "new segment declared without type code");
 242     code = 3;
 243   }
 244   if (nsegments == RDF_MAXSEGS) {
 245     error(ERR_FATAL, "reached compiled-in maximum segment limit (%d)",
 246           RDF_MAXSEGS);
 247     return NO_SEG;
 248   }
 249
 250   segments[nsegments].segname = nasm_strdup(name);
 251   i = seg_alloc();
 252   if (i % 2 != 0)
 253     error(ERR_PANIC, "seg_alloc() returned odd number");
 254   segments[nsegments].segnumber = i >> 1;
 255   segments[nsegments].segtype = code;
 256   segments[nsegments].segreserved = reserved;
 257   segments[nsegments].seglength = 0;
 258
 259   seg[nsegments] = saa_init(1L);
 260
 261   return i;
 262 }
 263
 264 static void write_reloc_rec(struct RelocRec *r)
 265 {
 266   char buf[4],*b;
 267
 268   if (r->refseg != (int16)NO_SEG && (r->refseg & 1)) /* segment base ref */
 269       r->type = 6;
 270
 271   r->refseg >>= 1;    /* adjust segment nos to RDF rather than NASM */
 272
 273   saa_wbytes(header,&r->type,1);
 274   saa_wbytes(header,&r->reclen,1);
 275   saa_wbytes(header,&r->segment,1);
 276   b = buf; WRITELONG(b,r->offset);
 277   saa_wbytes(header,buf,4);
 278   saa_wbytes(header,&r->length,1);
 279   b = buf; WRITESHORT(b,r->refseg);
 280   saa_wbytes(header,buf,2);
 281   headerlength += r->reclen + 2;
 282 }
 283
 284 static void write_export_rec(struct ExportRec *r)
 285 {
 286   char buf[4], *b;
 287
 288   r->segment >>= 1;
 289
 290   saa_wbytes(header,&r->type,1);
 291   saa_wbytes(header,&r->reclen,1);
 292   saa_wbytes(header,&r->segment,1);
 293   b = buf; WRITELONG(b,r->offset);
 294   saa_wbytes(header,buf,4);
 295   saa_wbytes(header,r->label,strlen(r->label) + 1);
 296   headerlength += r->reclen + 2;
 297 }
 298
 299 static void write_import_rec(struct ImportRec *r)
 300 {
 301   char buf[4], *b;
 302
 303   r->segment >>= 1;
 304
 305   saa_wbytes(header,&r->type,1);
 306   saa_wbytes(header,&r->reclen,1);
 307   b = buf; WRITESHORT(b,r->segment);
 308   saa_wbytes(header,buf,2);
 309   saa_wbytes(header,r->label,strlen(r->label) + 1);
 310   headerlength += r->reclen + 2;
 311 }
 312
 313 static void write_bss_rec(struct BSSRec *r)
 314 {
 315     char buf[4], *b;
 316
 317     saa_wbytes(header,&r->type,1);
 318     saa_wbytes(header,&r->reclen,1);
 319     b = buf; WRITELONG(b,r->amount);
 320     saa_wbytes(header,buf,4);
 321     headerlength += r->reclen + 2;
 322 }
 323
 324 static void write_dll_rec(struct DLLRec *r)
 325 {
 326     saa_wbytes(header,&r->type,1);
 327     saa_wbytes(header,&r->reclen,1);
 328     saa_wbytes(header,r->libname,strlen(r->libname) + 1);
 329     headerlength += r->reclen + 2;
 330 }
 331
 332 static void rdf2_deflabel(char *name, long segment, long offset,
 333                          int is_global, char *special)
 334 {
 335   struct ExportRec r;
 336   struct ImportRec ri;
 337 #ifdef VERBOSE_WARNINGS
 338   static int warned_common = 0;
 339 #endif
 340   static int farsym = 0;
 341   static int i;
 342
 343   if (special) {
 344     while(*special == ' ' || *special == '\t') special++;
 345
 346     if (!nasm_stricmp(special, "far")) {
 347       farsym = 1;
 348     }
 349     else if (!nasm_stricmp(special, "near")) {
 350       farsym = 0;
 351     }
 352     else
 353       error(ERR_NONFATAL, "unrecognised symbol type `%s'", special);
 354   }
 355
 356   if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
 357     error (ERR_NONFATAL, "unrecognised special symbol `%s'", name);
 358     return;
 359   }
 360
 361   if (is_global == 2) {
 362 #ifdef VERBOSE_WARNINGS
 363     if (!warned_common) {
 364       error(ERR_WARNING,"common declarations not supported: using extern");
 365       warned_common = 1;
 366     }
 367 #endif
 368     is_global = 1;
 369   }
 370
 371   for (i = 0; i < nsegments; i++) {
 372     if (segments[i].segnumber == segment>>1) break;
 373   }
 374   if (i >= nsegments) {   /* EXTERN declaration */
 375     if (farsym)
 376       ri.type = 7;
 377     else
 378       ri.type = 2;
 379     ri.segment = segment;
 380     strncpy(ri.label,name,32);
 381     ri.label[32] = 0;
 382     ri.reclen = 3 + strlen(ri.label);
 383     write_import_rec(&ri);
 384   } else if (is_global) {
 385     r.type = 3;
 386     r.segment = segment;
 387     r.offset = offset;
 388     strncpy(r.label,name,32);
 389     r.label[32] = 0;
 390     r.reclen = 6 + strlen(r.label);
 391     write_export_rec(&r);
 392   }
 393 }
 394
 395 static void membufwrite(int segment, void * data, int bytes)
 396 {
 397   int i;
 398   char buf[4], * b;
 399
 400   for (i = 0; i < nsegments; i++) {
 401     if (segments[i].segnumber == segment) break;
 402   }
 403   if (i == nsegments)
 404     error(ERR_PANIC, "can't find segment %d", segment);
 405
 406   if (bytes < 0) {
 407     b = buf;
 408     if (bytes == -2)
 409       WRITESHORT(b,*(short *)data);
 410     else
 411       WRITELONG(b,*(long *)data);
 412     data = buf;
 413     bytes = -bytes;
 414   }
 415   segments[i].seglength += bytes;
 416   saa_wbytes(seg[i],data,bytes);
 417 }
 418
 419 static int getsegmentlength(int segment)
 420 {
 421   int i;
 422   for (i = 0; i < nsegments; i++) {
 423     if (segments[i].segnumber == segment) break;
 424   }
 425   if (i == nsegments)
 426     error(ERR_PANIC, "can't find segment %d", segment);
 427
 428   return segments[i].seglength;
 429 }
 430
 431 static void rdf2_out (long segto, void *data, unsigned long type,
 432                      long segment, long wrt)
 433 {
 434   long bytes = type & OUT_SIZMASK;
 435   struct RelocRec rr;
 436   unsigned char databuf[4],*pd;
 437   int seg;
 438
 439   if (segto == NO_SEG) {
 440       if ((type & OUT_TYPMASK) != OUT_RESERVE)
 441           error (ERR_NONFATAL, "attempt to assemble code in ABSOLUTE space");
 442       return;
 443   }
 444
 445   segto >>= 1;    /* convert NASM segment no to RDF number */
 446
 447   for (seg = 0; seg < nsegments; seg++) {
 448     if (segments[seg].segnumber == segto) break;
 449   }
 450   if (seg >= nsegments) {
 451     error(ERR_NONFATAL,"specified segment not supported by rdf output format");
 452     return;
 453   }
 454
 455   if (wrt != NO_SEG) {
 456     wrt = NO_SEG;                      /* continue to do _something_ */
 457     error (ERR_NONFATAL, "WRT not supported by rdf output format");
 458   }
 459
 460   type &= OUT_TYPMASK;
 461
 462   if (segto == 2 && type != OUT_RESERVE)
 463   {
 464       error(ERR_NONFATAL, "BSS segments may not be initialised");
 465
 466       /* just reserve the space for now... */
 467
 468       if (type == OUT_REL2ADR)
 469         bytes = 2;
 470       else
 471         bytes = 4;
 472       type = OUT_RESERVE;
 473   }
 474
 475   if (type == OUT_RESERVE) {
 476       if (segto == 2)           /* BSS segment space reserverd */
 477           bsslength += bytes;
 478       else
 479         while (bytes --)
 480             membufwrite(segto,databuf,1);
 481   }
 482   else if (type == OUT_RAWDATA) {
 483       if (segment != NO_SEG)
 484           error(ERR_PANIC, "OUT_RAWDATA with other than NO_SEG");
 485
 486       membufwrite(segto,data,bytes);
 487   }
 488   else if (type == OUT_ADDRESS) {
 489
 490     /* if segment == NO_SEG then we are writing an address of an
 491        object within the same segment - do not produce reloc rec. */
 492
 493     /* FIXME - is this behaviour sane? at first glance it doesn't
 494        appear to be. Must test this thoroughly...! */
 495
 496     if (segment != NO_SEG)
 497     {
 498         /* it's an address, so we must write a relocation record */
 499
 500         rr.type = 1;            /* type signature */
 501         rr.reclen = 8;
 502         rr.segment = segto;             /* segment we're currently in */
 503         rr.offset = getsegmentlength(segto);    /* current offset */
 504         rr.length = bytes;              /* length of reference */
 505         rr.refseg = segment;    /* segment referred to */
 506         write_reloc_rec(&rr);
 507     }
 508
 509     pd = databuf;       /* convert address to little-endian */
 510     if (bytes == 2)
 511       WRITESHORT (pd, *(long *)data);
 512     else
 513       WRITELONG (pd, *(long *)data);
 514
 515     membufwrite(segto,databuf,bytes);
 516
 517   }
 518   else if (type == OUT_REL2ADR)
 519   {
 520     if (segment == segto)
 521       error(ERR_PANIC, "intra-segment OUT_REL2ADR");
 522
 523     rr.reclen = 8;
 524     rr.offset = getsegmentlength(segto);        /* current offset */
 525     rr.length = 2;              /* length of reference */
 526     rr.refseg = segment;        /* segment referred to (will be >>1'd)*/
 527
 528     if (segment != NO_SEG && segment % 2) {
 529       rr.type = 6;
 530       rr.segment = segto;       /* memory base refs *aren't ever* relative! */
 531       write_reloc_rec(&rr);
 532
 533       /* what do we put in the code? Simply the data. This should almost
 534        * always be zero, unless someone's doing segment arithmetic...
 535        */
 536       rr.offset = *(long *) data;
 537     }
 538     else
 539     {
 540       rr.type = 1;              /* type signature */
 541       rr.segment = segto+64;    /* segment we're currently in + rel flag */
 542       write_reloc_rec(&rr);
 543
 544       /* work out what to put in the code: offset of the end of this operand,
 545        * subtracted from any data specified, so that loader can just add
 546        * address of imported symbol onto it to get address relative to end of
 547        * instruction: import_address + data(offset) - end_of_instrn */
 548
 549       rr.offset = *(long *)data -(rr.offset + bytes);
 550     }
 551
 552     membufwrite(segto,&rr.offset,-2);
 553   }
 554   else if (type == OUT_REL4ADR)
 555   {
 556     if (segment == segto)
 557       error(ERR_PANIC, "intra-segment OUT_REL4ADR");
 558     if (segment != NO_SEG && segment % 2) {
 559       error(ERR_PANIC, "erm... 4 byte segment base ref?");
 560     }
 561
 562     rr.type = 1;                /* type signature */
 563     rr.segment = segto+64;      /* segment we're currently in + rel tag */
 564     rr.offset = getsegmentlength(segto);        /* current offset */
 565     rr.length = 4;              /* length of reference */
 566     rr.refseg = segment;        /* segment referred to */
 567     rr.reclen = 8;
 568     write_reloc_rec(&rr);
 569
 570     rr.offset = *(long *)data -(rr.offset + bytes);
 571
 572     membufwrite(segto,&rr.offset,-4);
 573   }
 574 }
 575
 576 static void rdf2_cleanup (int debuginfo) {
 577   long          l;
 578   struct BSSRec bs;
 579   int           i;
 580
 581     (void) debuginfo;
 582
 583   /* should write imported & exported symbol declarations to header here */
 584
 585   /* generate the output file... */
 586   fwrite(RDOFF2Id,6,1,ofile);   /* file type magic number */
 587
 588   if (bsslength != 0)           /* reserve BSS */
 589   {
 590       bs.type = 5;
 591       bs.amount = bsslength;
 592       bs.reclen = 4;
 593       write_bss_rec(&bs);
 594   }
 595
 596   /*
 597    * calculate overall length of the output object
 598    */
 599   l = headerlength + 4;
 600
 601   for (i = 0; i < nsegments; i++) {
 602     if (i == 2) continue;       /* skip BSS segment */
 603     l += 10 + segments[i].seglength;
 604   }
 605   l += 10;      /* null segment */
 606
 607   fwritelong(l, ofile);
 608
 609   fwritelong(headerlength, ofile);
 610   saa_fpwrite(header,ofile);    /* dump header */
 611   saa_free(header);
 612
 613   for (i = 0; i < nsegments; i++) {
 614     if (i == 2) continue;
 615
 616     fwriteshort(segments[i].segtype, ofile);
 617     fwriteshort(segments[i].segnumber, ofile);
 618     fwriteshort(segments[i].segreserved, ofile);
 619     fwritelong(segments[i].seglength, ofile);
 620
 621     saa_fpwrite(seg[i], ofile);
 622     saa_free(seg[i]);
 623   }
 624
 625   /* null segment - write 10 bytes of zero */
 626   fwritelong(0,ofile);
 627   fwritelong(0,ofile);
 628   fwriteshort(0,ofile);
 629
 630   fclose(ofile);
 631 }
 632
 633 static long rdf2_segbase (long segment) {
 634     return segment;
 635 }
 636
 637 static int rdf2_directive (char *directive, char *value, int pass) {
 638     struct DLLRec r;
 639
 640     if (! strcmp(directive, "library")) {
 641         if (pass == 1) {
 642             r.type = 4;
 643             strcpy(r.libname, value);
 644             write_dll_rec(&r);
 645         }
 646         return 1;
 647     }
 648
 649     return 0;
 650 }
 651
 652 static void rdf2_filename (char *inname, char *outname, efunc error) {
 653   standard_extension(inname,outname,".rdf",error);
 654 }
 655
 656 static char *rdf2_stdmac[] = {
 657     "%define __SECT__ [section .text]",
 658     "%imacro library 1+.nolist",
 659     "[library %1]",
 660     "%endmacro",
 661     "%macro __NASM_CDecl__ 1",
 662     "%endmacro",
 663     NULL
 664 };
 665
 666 static int rdf2_set_info(enum geninfo type, char **val)
 667 {
 668     return 0;
 669 }
 670
 671
 672 struct ofmt of_rdf2 = {
 673   "Relocatable Dynamic Object File Format v2.0",
 674   "rdf",
 675   NULL,
 676   null_debug_arr,
 677   &null_debug_form,
 678   rdf2_stdmac,
 679   rdf2_init,
 680   rdf2_set_info,
 681   rdf2_out,
 682   rdf2_deflabel,
 683   rdf2_section_names,
 684   rdf2_segbase,
 685   rdf2_directive,
 686   rdf2_filename,
 687   rdf2_cleanup
 688 };
 689
 690 #endif /* OF_RDF2 */