1 /* outelf.c output routines for the Netwide Assembler to produce
2 * ELF32 (i386 of course) object file format
4 * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
5 * Julian Hall. All rights reserved. The software is
6 * redistributable under the licence given in the file "Licence"
7 * distributed in the NASM archive.
24 #define R_386_32 1 /* ordinary absolute relocation */
25 #define R_386_PC32 2 /* PC-relative relocation */
26 #define R_386_GOT32 3 /* an offset into GOT */
27 #define R_386_PLT32 4 /* a PC-relative offset into PLT */
28 #define R_386_GOTOFF 9 /* an offset from GOT base */
29 #define R_386_GOTPC 10 /* a PC-relative offset _to_ GOT */
33 long address; /* relative to _start_ of section */
34 long symbol; /* ELF symbol info thingy */
35 int type; /* type of relocation */
39 long strpos; /* string table position of name */
40 long section; /* section ID of the symbol */
41 int type; /* symbol type */
42 long value; /* address, or COMMON variable align */
43 long size; /* size of symbol */
44 long globnum; /* symbol table offset if global */
45 struct Symbol *next; /* list of globals in each section */
46 struct Symbol *nextfwd; /* list of unresolved-size symbols */
47 char *name; /* used temporarily if in above list */
50 #define SHT_PROGBITS 1
55 #define SHF_EXECINSTR 4
59 unsigned long len, size, nrelocs;
61 int type; /* SHT_PROGBITS or SHT_NOBITS */
62 int align; /* alignment: power of two */
63 unsigned long flags; /* section flags */
67 struct Reloc *head, **tail;
68 struct Symbol *gsyms; /* global symbols in section */
72 static struct Section **sects;
73 static int nsects, sectlen;
75 #define SHSTR_DELTA 256
76 static char *shstrtab;
77 static int shstrtablen, shstrtabsize;
79 static struct SAA *syms;
80 static unsigned long nlocals, nglobs;
84 static struct RAA *bsym;
86 static struct SAA *strs;
87 static unsigned long strslen;
91 static evalfunc evaluate;
93 static struct Symbol *fwds;
95 static char elf_module[FILENAME_MAX];
97 extern struct ofmt of_elf;
99 #define SHN_ABS 0xFFF1
100 #define SHN_COMMON 0xFFF2
103 #define SYM_SECTION 0x04
104 #define SYM_GLOBAL 0x10
105 #define SYM_DATA 0x01
106 #define SYM_FUNCTION 0x02
108 #define GLOBAL_TEMP_BASE 15 /* bigger than any constant sym id */
110 #define SEG_ALIGN 16 /* alignment of sections in file */
111 #define SEG_ALIGN_1 (SEG_ALIGN-1)
113 static const char align_str[SEG_ALIGN] = ""; /* ANSI will pad this with 0s */
115 #define ELF_MAX_SECTIONS 16 /* really 10, but let's play safe */
116 static struct ELF_SECTDATA {
121 static int elf_nsect;
122 static long elf_foffs;
124 static void elf_write(void);
125 static void elf_sect_write(struct Section *, unsigned char *, unsigned long);
126 static void elf_section_header (int, int, int, void *, int, long,
128 static void elf_write_sections (void);
129 static struct SAA *elf_build_symtab (long *, long *);
130 static struct SAA *elf_build_reltab (long *, struct Reloc *);
131 static void add_sectname (char *, char *);
134 * Special section numbers which are used to define ELF special
135 * symbols, which can be used with WRT to provide PIC relocation
138 static long elf_gotpc_sect, elf_gotoff_sect;
139 static long elf_got_sect, elf_plt_sect;
140 static long elf_sym_sect;
142 static void elf_init(FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval)
147 (void) ldef; /* placate optimisers */
149 nsects = sectlen = 0;
150 syms = saa_init((long)sizeof(struct Symbol));
151 nlocals = nglobs = 0;
154 saa_wbytes (strs, "\0", 1L);
155 saa_wbytes (strs, elf_module, (long)(strlen(elf_module)+1));
156 strslen = 2+strlen(elf_module);
158 shstrtablen = shstrtabsize = 0;;
159 add_sectname ("", "");
163 elf_gotpc_sect = seg_alloc();
164 ldef("..gotpc", elf_gotpc_sect+1, 0L, NULL, FALSE, FALSE, &of_elf, error);
165 elf_gotoff_sect = seg_alloc();
166 ldef("..gotoff", elf_gotoff_sect+1, 0L, NULL, FALSE, FALSE,&of_elf,error);
167 elf_got_sect = seg_alloc();
168 ldef("..got", elf_got_sect+1, 0L, NULL, FALSE, FALSE, &of_elf, error);
169 elf_plt_sect = seg_alloc();
170 ldef("..plt", elf_plt_sect+1, 0L, NULL, FALSE, FALSE, &of_elf, error);
171 elf_sym_sect = seg_alloc();
172 ldef("..sym", elf_sym_sect+1, 0L, NULL, FALSE, FALSE, &of_elf, error);
174 def_seg = seg_alloc();
177 static void elf_cleanup(int debuginfo)
186 for (i=0; i<nsects; i++) {
187 if (sects[i]->type != SHT_NOBITS)
188 saa_free (sects[i]->data);
190 saa_free (sects[i]->rel);
191 while (sects[i]->head) {
193 sects[i]->head = sects[i]->head->next;
203 static void add_sectname (char *firsthalf, char *secondhalf)
205 int len = strlen(firsthalf)+strlen(secondhalf);
206 while (shstrtablen + len + 1 > shstrtabsize)
207 shstrtab = nasm_realloc (shstrtab, (shstrtabsize += SHSTR_DELTA));
208 strcpy (shstrtab+shstrtablen, firsthalf);
209 strcat (shstrtab+shstrtablen, secondhalf);
210 shstrtablen += len+1;
213 static int elf_make_section (char *name, int type, int flags, int align)
217 s = nasm_malloc (sizeof(*s));
219 if (type != SHT_NOBITS)
220 s->data = saa_init (1L);
223 s->len = s->size = 0;
225 if (!strcmp(name, ".text"))
228 s->index = seg_alloc();
229 add_sectname ("", name);
230 s->name = nasm_malloc (1+strlen(name));
231 strcpy (s->name, name);
237 if (nsects >= sectlen)
238 sects = nasm_realloc (sects, (sectlen += SECT_DELTA)*sizeof(*sects));
244 static long elf_section_names (char *name, int pass, int *bits)
247 int flags_and, flags_or, type, align, i;
250 * Default is 32 bits.
258 while (*p && !isspace(*p)) p++;
260 flags_and = flags_or = type = align = 0;
262 while (*p && isspace(*p)) p++;
265 while (*p && !isspace(*p)) p++;
267 while (*p && isspace(*p)) p++;
269 if (!nasm_strnicmp(q, "align=", 6)) {
273 if ( (align-1) & align ) { /* means it's not a power of two */
274 error (ERR_NONFATAL, "section alignment %d is not"
275 " a power of two", align);
278 } else if (!nasm_stricmp(q, "alloc")) {
279 flags_and |= SHF_ALLOC;
280 flags_or |= SHF_ALLOC;
281 } else if (!nasm_stricmp(q, "noalloc")) {
282 flags_and |= SHF_ALLOC;
283 flags_or &= ~SHF_ALLOC;
284 } else if (!nasm_stricmp(q, "exec")) {
285 flags_and |= SHF_EXECINSTR;
286 flags_or |= SHF_EXECINSTR;
287 } else if (!nasm_stricmp(q, "noexec")) {
288 flags_and |= SHF_EXECINSTR;
289 flags_or &= ~SHF_EXECINSTR;
290 } else if (!nasm_stricmp(q, "write")) {
291 flags_and |= SHF_WRITE;
292 flags_or |= SHF_WRITE;
293 } else if (!nasm_stricmp(q, "nowrite")) {
294 flags_and |= SHF_WRITE;
295 flags_or &= ~SHF_WRITE;
296 } else if (!nasm_stricmp(q, "progbits")) {
298 } else if (!nasm_stricmp(q, "nobits")) {
303 if (!strcmp(name, ".comment") ||
304 !strcmp(name, ".shstrtab") ||
305 !strcmp(name, ".symtab") ||
306 !strcmp(name, ".strtab")) {
307 error (ERR_NONFATAL, "attempt to redefine reserved section"
312 for (i=0; i<nsects; i++)
313 if (!strcmp(name, sects[i]->name))
316 if (!strcmp(name, ".text"))
317 i = elf_make_section (name, SHT_PROGBITS,
318 SHF_ALLOC | SHF_EXECINSTR, 16);
319 else if (!strcmp(name, ".data"))
320 i = elf_make_section (name, SHT_PROGBITS,
321 SHF_ALLOC | SHF_WRITE, 4);
322 else if (!strcmp(name, ".bss"))
323 i = elf_make_section (name, SHT_NOBITS,
324 SHF_ALLOC | SHF_WRITE, 4);
326 i = elf_make_section (name, SHT_PROGBITS, SHF_ALLOC, 1);
328 sects[i]->type = type;
330 sects[i]->align = align;
331 sects[i]->flags &= ~flags_and;
332 sects[i]->flags |= flags_or;
333 } else if (pass == 1) {
334 if (type || align || flags_and)
335 error (ERR_WARNING, "section attributes ignored on"
336 " redeclaration of section `%s'", name);
339 return sects[i]->index;
342 static void elf_deflabel (char *name, long segment, long offset,
343 int is_global, char *special)
347 int special_used = FALSE;
349 #if defined(DEBUG) && DEBUG>2
350 fprintf(stderr, " elf_deflabel: %s, seg=%ld, off=%ld, is_global=%d, %s\n",
351 name, segment, offset, is_global, special);
353 if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
355 * This is a NASM special symbol. We never allow it into
356 * the ELF symbol table, even if it's a valid one. If it
357 * _isn't_ a valid one, we should barf immediately.
359 if (strcmp(name, "..gotpc") && strcmp(name, "..gotoff") &&
360 strcmp(name, "..got") && strcmp(name, "..plt") &&
361 strcmp(name, "..sym"))
362 error (ERR_NONFATAL, "unrecognised special symbol `%s'", name);
366 if (is_global == 3) {
369 * Fix up a forward-reference symbol size from the first
372 for (s = &fwds; *s; s = &(*s)->nextfwd)
373 if (!strcmp((*s)->name, name)) {
374 struct tokenval tokval;
378 while (*p && !isspace(*p)) p++;
379 while (*p && isspace(*p)) p++;
382 tokval.t_type = TOKEN_INVALID;
383 e = evaluate(stdscan, NULL, &tokval, NULL, 1, error, NULL);
386 error (ERR_NONFATAL, "cannot use relocatable"
387 " expression as symbol size");
389 (*s)->size = reloc_value(e);
393 * Remove it from the list of unresolved sizes.
395 nasm_free ((*s)->name);
399 return; /* it wasn't an important one */
402 saa_wbytes (strs, name, (long)(1+strlen(name)));
403 strslen += 1+strlen(name);
405 sym = saa_wstruct (syms);
408 sym->type = is_global ? SYM_GLOBAL : 0;
410 if (segment == NO_SEG)
411 sym->section = SHN_ABS;
414 sym->section = SHN_UNDEF;
415 if (nsects == 0 && segment == def_seg) {
417 if (segment != elf_section_names (".text", 2, &tempint))
418 error (ERR_PANIC, "strange segment conditions in ELF driver");
419 sym->section = nsects;
421 for (i=0; i<nsects; i++)
422 if (segment == sects[i]->index) {
429 if (is_global == 2) {
432 sym->section = SHN_COMMON;
434 * We have a common variable. Check the special text to see
435 * if it's a valid number and power of two; if so, store it
436 * as the alignment for the common variable.
440 sym->value = readnum (special, &err);
442 error(ERR_NONFATAL, "alignment constraint `%s' is not a"
443 " valid number", special);
444 else if ( (sym->value | (sym->value-1)) != 2*sym->value - 1)
445 error(ERR_NONFATAL, "alignment constraint `%s' is not a"
446 " power of two", special);
450 sym->value = (sym->section == SHN_UNDEF ? 0 : offset);
452 if (sym->type == SYM_GLOBAL) {
454 * There's a problem here that needs fixing.
455 * If sym->section == SHN_ABS, then the first line of the
456 * else section causes a core dump, because its a reference
457 * beyond the end of the section array.
458 * This behaviour is exhibited by this code:
462 * I'm not sure how to procede, because I haven't got the
463 * first clue about how ELF works, so I don't know what to
464 * do with it. Furthermore, I'm not sure what the rest of this
465 * section of code does. Help?
467 * For now, I'll see if doing absolutely nothing with it will
470 if (sym->section == SHN_UNDEF || sym->section == SHN_COMMON)
472 bsym = raa_write (bsym, segment, nglobs);
474 else if (sym->section != SHN_ABS)
477 * This is a global symbol; so we must add it to the linked
478 * list of global symbols in its section. We'll push it on
479 * the beginning of the list, because it doesn't matter
480 * much which end we put it on and it's easier like this.
482 * In addition, we check the special text for symbol
483 * type and size information.
485 sym->next = sects[sym->section-1]->gsyms;
486 sects[sym->section-1]->gsyms = sym;
489 int n = strcspn(special, " ");
491 if (!nasm_strnicmp(special, "function", n))
492 sym->type |= SYM_FUNCTION;
493 else if (!nasm_strnicmp(special, "data", n) ||
494 !nasm_strnicmp(special, "object", n))
495 sym->type |= SYM_DATA;
497 error(ERR_NONFATAL, "unrecognised symbol type `%.*s'",
500 struct tokenval tokval;
503 char *saveme=stdscan_bufptr; /* bugfix? fbk 8/10/00 */
505 while (special[n] && isspace(special[n]))
508 * We have a size expression; attempt to
512 stdscan_bufptr = special+n;
513 tokval.t_type = TOKEN_INVALID;
514 e = evaluate(stdscan, NULL, &tokval, &fwd, 0, error, NULL);
518 sym->name = nasm_strdup(name);
521 error (ERR_NONFATAL, "cannot use relocatable"
522 " expression as symbol size");
524 sym->size = reloc_value(e);
526 stdscan_bufptr=saveme; /* bugfix? fbk 8/10/00 */
531 sym->globnum = nglobs;
536 if (special && !special_used)
537 error(ERR_NONFATAL, "no special symbol features supported here");
540 static void elf_add_reloc (struct Section *sect, long segment,
545 r = *sect->tail = nasm_malloc(sizeof(struct Reloc));
546 sect->tail = &r->next;
549 r->address = sect->len;
550 if (segment == NO_SEG)
555 for (i=0; i<nsects; i++)
556 if (segment == sects[i]->index)
559 r->symbol = GLOBAL_TEMP_BASE + raa_read(bsym, segment);
567 * This routine deals with ..got and ..sym relocations: the more
568 * complicated kinds. In shared-library writing, some relocations
569 * with respect to global symbols must refer to the precise symbol
570 * rather than referring to an offset from the base of the section
571 * _containing_ the symbol. Such relocations call to this routine,
572 * which searches the symbol list for the symbol in question.
574 * R_386_GOT32 references require the _exact_ symbol address to be
575 * used; R_386_32 references can be at an offset from the symbol.
576 * The boolean argument `exact' tells us this.
578 * Return value is the adjusted value of `addr', having become an
579 * offset from the symbol rather than the section. Should always be
580 * zero when returning from an exact call.
582 * Limitation: if you define two symbols at the same place,
583 * confusion will occur.
585 * Inefficiency: we search, currently, using a linked list which
586 * isn't even necessarily sorted.
588 static long elf_add_gsym_reloc (struct Section *sect,
589 long segment, long offset,
594 struct Symbol *sym, *sm;
598 * First look up the segment/offset pair and find a global
599 * symbol corresponding to it. If it's not one of our segments,
600 * then it must be an external symbol, in which case we're fine
601 * doing a normal elf_add_reloc after first sanity-checking
602 * that the offset from the symbol is zero.
605 for (i=0; i<nsects; i++)
606 if (segment == sects[i]->index) {
611 if (exact && offset != 0)
612 error (ERR_NONFATAL, "unable to find a suitable global symbol"
613 " for this reference");
615 elf_add_reloc (sect, segment, type);
621 * Find a symbol pointing _exactly_ at this one.
623 for (sym = s->gsyms; sym; sym = sym->next)
624 if (sym->value == offset)
628 * Find the nearest symbol below this one.
631 for (sm = s->gsyms; sm; sm = sm->next)
632 if (sm->value <= offset && (!sym || sm->value > sym->value))
636 error (ERR_NONFATAL, "unable to find a suitable global symbol"
637 " for this reference");
641 r = *sect->tail = nasm_malloc(sizeof(struct Reloc));
642 sect->tail = &r->next;
645 r->address = sect->len;
646 r->symbol = GLOBAL_TEMP_BASE + sym->globnum;
651 return offset - sym->value;
654 static void elf_out (long segto, void *data, unsigned long type,
655 long segment, long wrt)
658 long realbytes = type & OUT_SIZMASK;
660 unsigned char mydata[4], *p;
666 * handle absolute-assembly (structure definitions)
668 if (segto == NO_SEG) {
669 if (type != OUT_RESERVE)
670 error (ERR_NONFATAL, "attempt to assemble code in [ABSOLUTE]"
676 for (i=0; i<nsects; i++)
677 if (segto == sects[i]->index) {
682 int tempint; /* ignored */
683 if (segto != elf_section_names (".text", 2, &tempint))
684 error (ERR_PANIC, "strange segment conditions in ELF driver");
689 if (s->type == SHT_NOBITS && type != OUT_RESERVE) {
690 error(ERR_WARNING, "attempt to initialise memory in"
691 " BSS section `%s': ignored", s->name);
692 if (type == OUT_REL2ADR)
694 else if (type == OUT_REL4ADR)
700 if (type == OUT_RESERVE) {
701 if (s->type == SHT_PROGBITS) {
702 error(ERR_WARNING, "uninitialised space declared in"
703 " non-BSS section `%s': zeroing", s->name);
704 elf_sect_write (s, NULL, realbytes);
707 } else if (type == OUT_RAWDATA) {
708 if (segment != NO_SEG)
709 error(ERR_PANIC, "OUT_RAWDATA with other than NO_SEG");
710 elf_sect_write (s, data, realbytes);
711 } else if (type == OUT_ADDRESS) {
712 addr = *(long *)data;
713 if (segment != NO_SEG) {
715 error(ERR_NONFATAL, "ELF format does not support"
716 " segment base references");
719 elf_add_reloc (s, segment, R_386_32);
720 } else if (wrt == elf_gotpc_sect+1) {
722 * The user will supply GOT relative to $$. ELF
723 * will let us have GOT relative to $. So we
724 * need to fix up the data item by $-$$.
727 elf_add_reloc (s, segment, R_386_GOTPC);
728 } else if (wrt == elf_gotoff_sect+1) {
729 elf_add_reloc (s, segment, R_386_GOTOFF);
730 } else if (wrt == elf_got_sect+1) {
731 addr = elf_add_gsym_reloc (s, segment, addr,
733 } else if (wrt == elf_sym_sect+1) {
734 addr = elf_add_gsym_reloc (s, segment, addr,
736 } else if (wrt == elf_plt_sect+1) {
737 error(ERR_NONFATAL, "ELF format cannot produce non-PC-"
738 "relative PLT references");
740 error (ERR_NONFATAL, "ELF format does not support this"
742 wrt = NO_SEG; /* we can at least _try_ to continue */
747 if (realbytes != 4 && segment != NO_SEG)
748 error (ERR_NONFATAL, "ELF format does not support non-32-bit"
751 elf_sect_write (s, mydata, realbytes);
752 } else if (type == OUT_REL2ADR) {
753 error (ERR_NONFATAL, "ELF format does not support 16-bit"
755 } else if (type == OUT_REL4ADR) {
756 if (segment == segto)
757 error(ERR_PANIC, "intra-segment OUT_REL4ADR");
758 if (segment != NO_SEG && segment % 2) {
759 error(ERR_NONFATAL, "ELF format does not support"
760 " segment base references");
763 elf_add_reloc (s, segment, R_386_PC32);
764 } else if (wrt == elf_plt_sect+1) {
765 elf_add_reloc (s, segment, R_386_PLT32);
766 } else if (wrt == elf_gotpc_sect+1 ||
767 wrt == elf_gotoff_sect+1 ||
768 wrt == elf_got_sect+1) {
769 error(ERR_NONFATAL, "ELF format cannot produce PC-"
770 "relative GOT references");
772 error (ERR_NONFATAL, "ELF format does not support this"
774 wrt = NO_SEG; /* we can at least _try_ to continue */
778 WRITELONG (p, *(long*)data - realbytes);
779 elf_sect_write (s, mydata, 4L);
783 static void elf_write(void)
785 int nsections, align;
792 long symtablen, symtablocal;
795 * Work out how many sections we will have. We have SHN_UNDEF,
796 * then the flexible user sections, then the four fixed
797 * sections `.comment', `.shstrtab', `.symtab' and `.strtab',
798 * then optionally relocation sections for the user sections.
800 nsections = 5; /* SHN_UNDEF and the fixed ones */
801 add_sectname ("", ".comment");
802 add_sectname ("", ".shstrtab");
803 add_sectname ("", ".symtab");
804 add_sectname ("", ".strtab");
805 for (i=0; i<nsects; i++) {
806 nsections++; /* for the section itself */
807 if (sects[i]->head) {
808 nsections++; /* for its relocations */
809 add_sectname (".rel", sects[i]->name);
817 commlen = 2+sprintf(comment+1, "The Netwide Assembler %s", NASM_VER);
820 * Output the ELF header.
822 fwrite ("\177ELF\1\1\1\0\0\0\0\0\0\0\0\0", 16, 1, elffp);
823 fwriteshort (1, elffp); /* ET_REL relocatable file */
824 fwriteshort (3, elffp); /* EM_386 processor ID */
825 fwritelong (1L, elffp); /* EV_CURRENT file format version */
826 fwritelong (0L, elffp); /* no entry point */
827 fwritelong (0L, elffp); /* no program header table */
828 fwritelong (0x40L, elffp); /* section headers straight after
829 * ELF header plus alignment */
830 fwritelong (0L, elffp); /* 386 defines no special flags */
831 fwriteshort (0x34, elffp); /* size of ELF header */
832 fwriteshort (0, elffp); /* no program header table, again */
833 fwriteshort (0, elffp); /* still no program header table */
834 fwriteshort (0x28, elffp); /* size of section header */
835 fwriteshort (nsections, elffp); /* number of sections */
836 fwriteshort (nsects+2, elffp); /* string table section index for
837 * section header table */
838 fwritelong (0L, elffp); /* align to 0x40 bytes */
839 fwritelong (0L, elffp);
840 fwritelong (0L, elffp);
843 * Build the symbol table and relocation tables.
845 symtab = elf_build_symtab (&symtablen, &symtablocal);
846 for (i=0; i<nsects; i++)
848 sects[i]->rel = elf_build_reltab (§s[i]->rellen,
852 * Now output the section header table.
855 elf_foffs = 0x40 + 0x28 * nsections;
856 align = ((elf_foffs+SEG_ALIGN_1) & ~SEG_ALIGN_1) - elf_foffs;
859 elf_sects = nasm_malloc(sizeof(*elf_sects) * (2 * nsects + 10));
861 elf_section_header (0, 0, 0, NULL, FALSE, 0L, 0, 0, 0, 0); /* SHN_UNDEF */
863 for (i=0; i<nsects; i++) {
864 elf_section_header (p - shstrtab, sects[i]->type, sects[i]->flags,
865 (sects[i]->type == SHT_PROGBITS ?
866 sects[i]->data : NULL), TRUE,
867 sects[i]->len, 0, 0, sects[i]->align, 0);
870 elf_section_header (p - shstrtab, 1, 0, comment, FALSE,
871 (long)commlen, 0, 0, 1, 0);/* .comment */
873 elf_section_header (p - shstrtab, 3, 0, shstrtab, FALSE,
874 (long)shstrtablen, 0, 0, 1, 0);/* .shstrtab */
876 elf_section_header (p - shstrtab, 2, 0, symtab, TRUE,
877 symtablen, nsects+4, symtablocal, 4, 16);/* .symtab */
879 elf_section_header (p - shstrtab, 3, 0, strs, TRUE,
880 strslen, 0, 0, 1, 0); /* .strtab */
881 for (i=0; i<nsects; i++) if (sects[i]->head) {
883 elf_section_header (p - shstrtab, 9, 0, sects[i]->rel, TRUE,
884 sects[i]->rellen, nsects+3, i+1, 4, 8);
887 fwrite (align_str, align, 1, elffp);
890 * Now output the sections.
892 elf_write_sections();
894 nasm_free (elf_sects);
898 static struct SAA *elf_build_symtab (long *len, long *local)
900 struct SAA *s = saa_init(1L);
902 unsigned char entry[16], *p;
908 * First, an all-zeros entry, required by the ELF spec.
910 saa_wbytes (s, NULL, 16L); /* null symbol table entry */
915 * Next, an entry for the file name.
918 WRITELONG (p, 1); /* we know it's 1st thing in strtab */
919 WRITELONG (p, 0); /* no value */
920 WRITELONG (p, 0); /* no size either */
921 WRITESHORT (p, 4); /* type FILE */
922 WRITESHORT (p, SHN_ABS);
923 saa_wbytes (s, entry, 16L);
928 * Now some standard symbols defining the segments, for relocation
931 for (i = 1; i <= nsects+1; i++) {
933 WRITELONG (p, 0); /* no symbol name */
934 WRITELONG (p, 0); /* offset zero */
935 WRITELONG (p, 0); /* size zero */
936 WRITESHORT (p, 3); /* local section-type thing */
937 WRITESHORT (p, (i==1 ? SHN_ABS : i-1)); /* the section id */
938 saa_wbytes (s, entry, 16L);
944 * Now the other local symbols.
947 while ( (sym = saa_rstruct (syms)) ) {
948 if (sym->type & SYM_GLOBAL)
951 WRITELONG (p, sym->strpos);
952 WRITELONG (p, sym->value);
953 WRITELONG (p, sym->size);
954 WRITESHORT (p, sym->type); /* local non-typed thing */
955 WRITESHORT (p, sym->section);
956 saa_wbytes (s, entry, 16L);
962 * Now the global symbols.
965 while ( (sym = saa_rstruct (syms)) ) {
966 if (!(sym->type & SYM_GLOBAL))
969 WRITELONG (p, sym->strpos);
970 WRITELONG (p, sym->value);
971 WRITELONG (p, sym->size);
972 WRITESHORT (p, sym->type); /* global non-typed thing */
973 WRITESHORT (p, sym->section);
974 saa_wbytes (s, entry, 16L);
981 static struct SAA *elf_build_reltab (long *len, struct Reloc *r) {
983 unsigned char *p, entry[8];
992 long sym = r->symbol;
994 if (sym >= GLOBAL_TEMP_BASE)
995 sym += -GLOBAL_TEMP_BASE + (nsects+3) + nlocals;
998 WRITELONG (p, r->address);
999 WRITELONG (p, (sym << 8) + r->type);
1000 saa_wbytes (s, entry, 8L);
1009 static void elf_section_header (int name, int type, int flags,
1010 void *data, int is_saa, long datalen,
1011 int link, int info, int align, int eltsize)
1013 elf_sects[elf_nsect].data = data;
1014 elf_sects[elf_nsect].len = datalen;
1015 elf_sects[elf_nsect].is_saa = is_saa;
1018 fwritelong ((long)name, elffp);
1019 fwritelong ((long)type, elffp);
1020 fwritelong ((long)flags, elffp);
1021 fwritelong (0L, elffp); /* no address, ever, in object files */
1022 fwritelong (type == 0 ? 0L : elf_foffs, elffp);
1023 fwritelong (datalen, elffp);
1025 elf_foffs += (datalen+SEG_ALIGN_1) & ~SEG_ALIGN_1;
1026 fwritelong ((long)link, elffp);
1027 fwritelong ((long)info, elffp);
1028 fwritelong ((long)align, elffp);
1029 fwritelong ((long)eltsize, elffp);
1032 static void elf_write_sections (void)
1035 for (i = 0; i < elf_nsect; i++)
1036 if (elf_sects[i].data) {
1037 long len = elf_sects[i].len;
1038 long reallen = (len+SEG_ALIGN_1) & ~SEG_ALIGN_1;
1039 long align = reallen - len;
1040 if (elf_sects[i].is_saa)
1041 saa_fpwrite (elf_sects[i].data, elffp);
1043 fwrite (elf_sects[i].data, len, 1, elffp);
1044 fwrite (align_str, align, 1, elffp);
1048 static void elf_sect_write (struct Section *sect,
1049 unsigned char *data, unsigned long len)
1051 saa_wbytes (sect->data, data, len);
1055 static long elf_segbase (long segment)
1060 static int elf_directive (char *directive, char *value, int pass)
1065 static void elf_filename (char *inname, char *outname, efunc error)
1067 strcpy(elf_module, inname);
1068 standard_extension (inname, outname, ".o", error);
1071 static char *elf_stdmac[] = {
1072 "%define __SECT__ [section .text]",
1073 "%macro __NASM_CDecl__ 1",
1078 static int elf_set_info(enum geninfo type, char **val)
1083 struct ofmt of_elf = {
1084 "ELF32 (i386) object files (e.g. Linux)",