aboutsummaryrefslogtreecommitdiff
path: root/gdb/xcoffexec.c
blob: c6d421fa1443f81afa44a7d165c8a343f8a5831f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
/* Execute AIXcoff files, for GDB.
   Copyright (C) 1988, 1989, 1991 Free Software Foundation, Inc.
   Derived from exec.c.  Modified by IBM Corporation.
   Donated by IBM Corporation and Cygnus Support.

This file is part of GDB.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* xcoff-exec -	deal with executing XCOFF files.  */
  
#include <stdio.h>
#include <sys/types.h>
#include <sys/param.h>
#include <fcntl.h>
#include <string.h>
#include <ctype.h>
#include <sys/stat.h>
#include <sys/ldr.h>

#include "defs.h"
#include "frame.h"
#include "inferior.h"
#include "target.h"
#include "gdbcmd.h"
#include "gdbcore.h"
#include "symfile.h"

#include "libbfd.h"		/* BFD internals (sigh!)  FIXME */

struct section_table *exec_sections, *exec_sections_end;

#define eq(s0, s1)	!strcmp(s0, s1)

/* Whether to open exec and core files read-only or read-write.  */

int write_files = 0;

bfd *exec_bfd;			/* needed by core.c	*/

extern char *getenv();
extern void child_create_inferior (), child_attach ();
extern void add_syms_addr_command ();
extern void symbol_file_command ();
static void exec_files_info();

/*
 * the vmap struct is used to describe the virtual address space of
 * the target we are manipulating.  The first entry is always the "exec"
 * file.  Subsequent entries correspond to other objects that are
 * mapped into the address space of a process created from the "exec" file.
 * These are either in response to exec()ing the file, in which case all
 * shared libraries are loaded, or a "load" system call, followed by the
 * user's issuance of a "load" command.
 */
struct vmap {
	struct vmap *nxt;	/* ^ to next in chain			*/
	bfd *bfd;		/* BFD for mappable object library	*/
	char *name;		/* ^ to object file name		*/
	char *member;		/* ^ to member name			*/
	CORE_ADDR tstart;	/* virtual addr where member is mapped	*/
	CORE_ADDR tend;		/* virtual upper bound of member	*/
	CORE_ADDR tadj;		/* heuristically derived adjustment	*/
	CORE_ADDR dstart;	/* virtual address of data start	*/
	CORE_ADDR dend;		/* vitrual address of data end		*/
};


struct vmap_and_bfd {
  bfd *pbfd;
  struct vmap *pvmap;
};

static struct vmap *vmap;	/* current vmap				*/

extern struct target_ops exec_ops;


/* exec_close -	done with exec file, clean up all resources. */

void
exec_close(quitting) {
	register struct vmap *vp, *nxt;

	for (nxt = vmap; vp = nxt; ) {
		nxt = vp->nxt;
		bfd_close(vp->bfd);
		free_named_symtabs(vp->name, vp->member);	/* XXX	*/
		free(vp);
	}

	vmap = 0;
	exec_bfd = 0;
}

/*
 * exec_file_command -	handle the "exec" command, &c.
 */
void
exec_file_command(filename, from_tty)
char *filename;
{
  bfd *bfd;

  target_preopen(from_tty);
  unpush_target(&exec_ops);

  /* Now open and digest the file the user requested, if any. */

  if (filename) {
  	char *scratch_pathname;
  	int scratch_chan;
      
  	filename = tilde_expand(filename);
  	make_cleanup(free, filename);
      
  	scratch_chan = openp(getenv("PATH"), 1, filename, O_RDONLY, 0
  			     , &scratch_pathname);
  	if (scratch_chan < 0)
	  perror_with_name(filename);

  	bfd = bfd_fdopenr(scratch_pathname, NULL, scratch_chan);
  	if (!bfd)
	  error("Could not open `%s' as an executable file: %s"
  		      , scratch_pathname, bfd_errmsg(bfd_error));

  	/* make sure we have an object file */

  	if (!bfd_check_format(bfd, bfd_object))
  		error("\"%s\": not in executable format: %s."
  		      , scratch_pathname, bfd_errmsg(bfd_error));


  	/* setup initial vmap */

  	map_vmap (bfd, 0);
  	if (!vmap)
  		error("Can't find the file sections in `%s': %s"
  		      , bfd->filename, bfd_errmsg(bfd_error));

  	exec_bfd = bfd;

	if (build_section_table (exec_bfd, &exec_sections, &exec_sections_end))
	  error ("Can't find the file sections in `%s': %s", 
  		exec_bfd->filename, bfd_errmsg (bfd_error));

  	/* make sure core, if present, matches */
  	validate_files();

  	push_target(&exec_ops);

  	/* Tell display code(if any) about the changed file name. */

  	if (exec_file_display_hook)
  		(*exec_file_display_hook)(filename);
  } 
  else {
  	exec_close(0);	/* just in case	*/
  	if (from_tty)
	  printf("No exec file now.\n");
  }
}

/* Set both the exec file and the symbol file, in one command.  What a
 * novelty.  Why did GDB go through four major releases before this
 * command was added?
 */
void
file_command(arg, from_tty)
char *arg; {

	exec_file_command(arg, from_tty);
	symbol_file_command(arg, from_tty);
}

/* Locate all mappable sections of a BFD file. 
   table_pp_char is a char * to get it through bfd_map_over_sections;
   we cast it back to its proper type.  */

void
add_to_section_table (abfd, asect, table_pp_char)
     bfd *abfd;
     sec_ptr asect;
     char *table_pp_char;
{
  struct section_table **table_pp = (struct section_table **)table_pp_char;
  flagword aflag;

  aflag = bfd_get_section_flags (abfd, asect);
  /* FIXME, we need to handle BSS segment here...it alloc's but doesn't load */
  if (!(aflag & SEC_LOAD))
    return;
  (*table_pp)->sec_ptr = asect;
  (*table_pp)->addr = bfd_section_vma (abfd, asect);
  (*table_pp)->endaddr = (*table_pp)->addr + bfd_section_size (abfd, asect);
  (*table_pp)++;
}

int
build_section_table (some_bfd, start, end)
     bfd *some_bfd;
     struct section_table **start, **end;
{
  unsigned count;

  count = bfd_count_sections (some_bfd);
  if (count == 0)
    abort();	/* return 1? */
  if (*start)
    free (*start);
  *start = (struct section_table *) xmalloc (count * sizeof (**start));
  *end = *start;
  bfd_map_over_sections (some_bfd, add_to_section_table, (char *)end);
  if (*end > *start + count)
    abort();
  /* We could realloc the table, but it probably loses for most files.  */
  return 0;
}

/*
 * lookup_symtab_bfd -	find if we currently have any symbol tables from bfd
 */
struct objfile *
lookup_objfile_bfd(bfd *bfd) {
	register struct objfile *s;

	for (s = object_files; s; s = s->next)
		if (s->obfd == bfd)
			return s;
	return 0;
}


void
sex_to_vmap(bfd *bf, sec_ptr sex, struct vmap_and_bfd *vmap_bfd) 
{
  register struct vmap *vp, **vpp;
  register struct symtab *syms;
  bfd *arch = vmap_bfd->pbfd;
  vp = vmap_bfd->pvmap;

  if ((bfd_get_section_flags(bf, sex) & SEC_LOAD) == 0)
    return;

  if (!strcmp(bfd_section_name(bf, sex), ".text")) {
    vp->tstart = 0;
    vp->tend   = vp->tstart + bfd_section_size(bf, sex);

    /* This is quite a tacky way to recognize the `exec' load segment (rather
       than shared libraries. You should use `arch' instead. FIXMEmgo */
    if (!vmap)
      vp->tadj = sex->filepos - bfd_section_vma(bf, sex);
    else
      vp->tadj = 0;
  }

  else if (!strcmp(bfd_section_name(bf, sex), ".data")) {
    vp->dstart = 0;
    vp->dend   = vp->dstart + bfd_section_size(bf, sex);
  }

  else if (!strcmp(bfd_section_name(bf, sex), ".bss"))	/* FIXMEmgo */
    printf ("bss section in exec! Don't know what the heck to do!\n");
}

/* Make a vmap for the BFD "bf", which might be a member of the archive
   BFD "arch".  If we have not yet read in symbols for this file, do so.  */

map_vmap (bfd *bf, bfd *arch)
{
  struct vmap_and_bfd vmap_bfd;
  struct vmap *vp, **vpp;
  struct objfile *obj;
  char *name;

  vp = (void*) xmalloc (sizeof (*vp));
  vp->nxt = 0;
  vp->bfd = bf;
  vp->name = bfd_get_filename(arch ? arch : bf);
  vp->member = arch ? bfd_get_filename(bf) : "";
  
  vmap_bfd.pbfd = arch;
  vmap_bfd.pvmap = vp;
  bfd_map_over_sections (bf, sex_to_vmap, &vmap_bfd);

  obj = lookup_objfile_bfd (bf);
  if (exec_bfd && !obj) {
    name = savestring (bfd_get_filename (bf), strlen (bfd_get_filename (bf)));
    obj = allocate_objfile (bf, name);
    syms_from_objfile (obj, 0, 0);
  }

  /* find the end of the list, and append. */
  for (vpp = &vmap; *vpp; vpp = &(*vpp)->nxt)
  ;
  *vpp = vp;
}


/* true, if symbol table and misc_function_vector is relocated. */

int symtab_relocated = 0;


/*  vmap_symtab -	handle symbol translation on vmapping */

vmap_symtab(vp, old_start, vip)
register struct vmap *vp;
CORE_ADDR old_start;
struct stat *vip; 
{
	register struct symtab *s;

	/*
	 * for each symbol table generated from the vp->bfd
	 */
	for (s = symtab_list; s; s = s->next) {

	  /* skip over if this is not relocatable and doesn't have a line table */
	  if (s->nonreloc && !LINETABLE (s))
	    continue;

		/* matching the symbol table's BFD and the *vp's BFD is hairy.
		   exec_file creates a seperate BFD for possibly the
		   same file as symbol_file.FIXME ALL THIS MUST BE RECTIFIED. */

		if (s->objfile->obfd == vp->bfd) {
			/* if they match, we luck out. */
			;
		} else if (vp->member[0]) {
			/* no match, and member present, not this one. */
			continue;
		} else {
			struct stat si;
			FILE *io;

			/*
			 * no match, and no member. need to be sure.
			 */
			io = bfd_cache_lookup(s->objfile->obfd);
			if (!io)
				fatal("cannot find BFD's iostream for sym");
			/*
			 * see if we are referring to the same file
			 */
			if (fstat(fileno(io), &si) < 0)
				fatal("cannot fstat BFD for sym");

			if (si.st_dev != vip->st_dev
			    || si.st_ino != vip->st_ino)
				continue;
		}

		if (vp->tstart != old_start)
		  vmap_symtab_1(s, vp, old_start);
	}

	if (vp->tstart != old_start)
	  fixup_misc_vector (vp->tstart - old_start);

	symtab_relocated = 1;
}


fixup_misc_vector (int disp)
{
  int ii;
  for (ii=0; ii < misc_function_count; ++ii)
    if (misc_function_vector[ii].address < 0x10000000)
      misc_function_vector[ii].address += disp;
}


vmap_symtab_1(s, vp, old_start)
register struct symtab *s;
register struct vmap *vp;
CORE_ADDR old_start; 
{
    register int i, j;
    int len, blen;
    register struct linetable *l;
    struct blockvector *bv;
    register struct block *b;
    int depth;
    register ulong reloc, dreloc;
    
    if ((reloc = vp->tstart - old_start) == 0)
	return;

    dreloc = vp->dstart;			/* data relocation */

    /*
     * The line table must be relocated.  This is only present for
     * b.text sections, so only vp->text type maps need be considered.
     */
    l = LINETABLE (s);
    len = l->nitems;
    for (i = 0; i < len; i++)
	l->item[i].pc += reloc;

    /* if this symbol table is not relocatable, only line table should
       be relocated and the rest ignored. */
    if (s->nonreloc)
      return;
    
    bv  = BLOCKVECTOR(s);
    len = BLOCKVECTOR_NBLOCKS(bv);
    
    for (i = 0; i < len; i++) {
	b = BLOCKVECTOR_BLOCK(bv, i);
	
	BLOCK_START(b) += reloc;
	BLOCK_END(b)   += reloc;
	
	blen = BLOCK_NSYMS(b);
	for (j = 0; j < blen; j++) {
	    register struct symbol *sym;
	    
	    sym = BLOCK_SYM(b, j);
	    switch (SYMBOL_NAMESPACE(sym)) {
	      case STRUCT_NAMESPACE:
	      case UNDEF_NAMESPACE:
		continue;
		
	      case LABEL_NAMESPACE:
	      case VAR_NAMESPACE:
		break;
	    }
	    
	    switch (SYMBOL_CLASS(sym)) {
	      case LOC_CONST:
	      case LOC_CONST_BYTES:
	      case LOC_LOCAL:
	      case LOC_REGISTER:
	      case LOC_ARG:
	      case LOC_LOCAL_ARG:
	      case LOC_REF_ARG:
	      case LOC_REGPARM:
	      case LOC_TYPEDEF:
		continue;
		
#ifdef FIXME
	      case LOC_EXTERNAL:
#endif
	      case LOC_LABEL:
		SYMBOL_VALUE_ADDRESS(sym) += reloc;
		break;

	      case LOC_STATIC:
		SYMBOL_VALUE_ADDRESS(sym) += dreloc;
		break;

	      case LOC_BLOCK:
		break;
		
	      default:
		fatal("botched symbol class %x"
		      , SYMBOL_CLASS(sym));
		break;
	    }
	}
    }
}

/*
 * add_vmap -	add a new vmap entry based on ldinfo() information
 */
add_vmap(ldi)
register struct ld_info *ldi; {
	bfd *bfd, *last;
	register char *mem;

	mem = ldi->ldinfo_filename + strlen(ldi->ldinfo_filename) + 1;
	bfd = bfd_fdopenr(ldi->ldinfo_filename, NULL, ldi->ldinfo_fd);
	if (!bfd)
		error("Could not open `%s' as an executable file: %s"
		      , ldi->ldinfo_filename, bfd_errmsg(bfd_error));


	/* make sure we have an object file */

	if (bfd_check_format(bfd, bfd_object))
		map_vmap (bfd, 0);

	else if (bfd_check_format(bfd, bfd_archive)) {
		last = 0;
		/*
		 * FIXME??? am I tossing BFDs?  bfd?
		 */
		while (last = bfd_openr_next_archived_file(bfd, last))
			if (eq(mem, last->filename))
				break;

		if (!last) {
			bfd_close(bfd);
/* FIXME -- should be error */
			warning("\"%s\": member \"%s\" missing.",
			      bfd->filename, mem);
			return;
		}

		if (!bfd_check_format(last, bfd_object)) {
			bfd_close(last);	/* XXX???	*/
			goto obj_err;
		}

		map_vmap (last, bfd);
	}
	else {
	    obj_err:
		bfd_close(bfd);
/* FIXME -- should be error */
		warning("\"%s\": not in executable format: %s."
		      , ldi->ldinfo_filename, bfd_errmsg(bfd_error));
		return;
	}
}


/* As well as symbol tables, exec_sections need relocation. Otherwise after
   the inferior process terminates, symbol table is relocated but there is
   no inferior process. Thus, we have to use `exec' bfd, rather than the inferior
   process's memory space, when lookipng at symbols.
   `exec_sections' need to be relocated only once though, as long as the exec
   file was not changed.
*/
vmap_exec ()
{
  static bfd *execbfd;
  if (execbfd == exec_bfd)
    return;

  execbfd = exec_bfd;

  if (!vmap || !exec_sections) {
    printf ("WARNING: vmap not found in vmap_exec()!\n");
    return;
  }
  /* First exec section is `.text', second is `.data'. If this is changed,
     then this routine will choke. Better you should check section names,
     FIXMEmgo. */
  exec_sections [0].addr += vmap->tstart;
  exec_sections [0].endaddr += vmap->tstart;
  exec_sections [1].addr += vmap->dstart;
  exec_sections [1].endaddr += vmap->dstart;
}


int
text_adjustment (abfd)
bfd *abfd;
{
  static bfd *execbfd;
  static int adjustment;
  sec_ptr  sect;

  if (exec_bfd == execbfd)
    return adjustment;

  sect = bfd_get_section_by_name (abfd, ".text");
  if (sect)
    adjustment = sect->filepos - sect->vma;
  else
    adjustment = 0x200;				/* just a wild assumption */

  return adjustment;
}


/*
 * vmap_ldinfo -	update VMAP info with ldinfo() information
 *
 * Input:
 *	ldi	-	^ to ldinfo() results.
 */
vmap_ldinfo(ldi)
register struct ld_info *ldi;
{
  struct stat ii, vi;
  register struct vmap *vp;
  register got_one, retried;
  CORE_ADDR ostart;

  /*
   * for each *ldi, see if we have a corresponding *vp
   *	if so, update the mapping, and symbol table.
   *	if not, add an entry and symbol table.
   */
  do {
	char *name = ldi->ldinfo_filename;
	char *memb = name + strlen(name) + 1;

	retried = 0;

	if (fstat(ldi->ldinfo_fd, &ii) < 0)
		fatal("cannot fstat(%d) on %s"
		      , ldi->ldinfo_fd
		      , name);
retry:
	for (got_one = 0, vp = vmap; vp; vp = vp->nxt) {
		FILE *io;

		/* The filenames are not always sufficient to match on. */
		if ((name[0] == "/"
		    && !eq(name, vp->name))
		    || (memb[0] && !eq(memb, vp->member)))
			continue;

		/* totally opaque! */
		io = bfd_cache_lookup(vp->bfd);
		if (!io)
			fatal("cannot find BFD's iostream for %s"
			      , vp->name);

		/* see if we are referring to the same file */
		if (fstat(fileno(io), &vi) < 0)
			fatal("cannot fstat BFD for %s", vp->name);

		if (ii.st_dev != vi.st_dev || ii.st_ino != vi.st_ino)
			continue;

		if (!retried)
		    close(ldi->ldinfo_fd);

		++got_one;

		/* found a corresponding VMAP. remap! */
		ostart = vp->tstart;

		vp->tstart = ldi->ldinfo_textorg;
		vp->tend   = vp->tstart + ldi->ldinfo_textsize;
		vp->dstart = ldi->ldinfo_dataorg;
		vp->dend   = vp->dstart + ldi->ldinfo_datasize;

		if (vp->tadj) {
		  vp->tstart += vp->tadj;
		  vp->tend   += vp->tadj;
		}

		/* relocate symbol table(s). */
		vmap_symtab(vp, ostart, &vi);

		/* there may be more, so we don't break out of the loop. */
	}

	/*
	 * if there was no matching *vp, we must perforce create
	 * the sucker(s)
	 */
	if (!got_one && !retried) {
		add_vmap(ldi);
		++retried;
		goto retry;
	}
  } while (ldi->ldinfo_next
	 && (ldi = (void *) (ldi->ldinfo_next + (char *) ldi)));

  breakpoint_re_set();
}

/*
 * vmap_inferior -	print VMAP info for inferior
 */
vmap_inferior() {

	if (inferior_pid == 0)
		return 0;		/* normal processing	*/

	exec_files_info();

	return 1;
}

/* Read or write the exec file.

   Args are address within exec file, address within gdb address-space,
   length, and a flag indicating whether to read or write.

   Result is a length:

	0:    We cannot handle this address and length.
	> 0:  We have handled N bytes starting at this address.
	      (If N == length, we did it all.)  We might be able
	      to handle more bytes beyond this length, but no
	      promises.
	< 0:  We cannot handle this address, but if somebody
	      else handles (-N) bytes, we can start from there.

    The same routine is used to handle both core and exec files;
    we just tail-call it with more arguments to select between them.  */

int
xfer_memory (memaddr, myaddr, len, write, abfd, sections, sections_end)
     CORE_ADDR memaddr;
     char *myaddr;
     int len;
     int write;
     bfd *abfd;
     struct section_table *sections, *sections_end;
{
  boolean res;
  struct section_table *p;
  CORE_ADDR nextsectaddr, memend;
  boolean (*xfer_fn) ();

  if (len <= 0)
    abort();

  memend = memaddr + len;
  xfer_fn = write? bfd_set_section_contents: bfd_get_section_contents;
  nextsectaddr = memend;

  for (p = sections; p < sections_end; p++)
    {
      if (p->addr <= memaddr)
	if (p->endaddr >= memend)
	  {
	    /* Entire transfer is within this section.  */
	    res = xfer_fn (abfd, p->sec_ptr, myaddr, memaddr - p->addr, len);
	    return (res != false)? len: 0;
	  }
	else if (p->endaddr <= memaddr)
	  {
	    /* This section ends before the transfer starts.  */
	    continue;
	  }
	else 
	  {
	    /* This section overlaps the transfer.  Just do half.  */
	    len = p->endaddr - memaddr;
	    res = xfer_fn (abfd, p->sec_ptr, myaddr, memaddr - p->addr, len);
	    return (res != false)? len: 0;
	  }
      else if (p->addr < nextsectaddr)
	nextsectaddr = p->addr;
    }

  if (nextsectaddr >= memend)
    return 0;				/* We can't help */
  else
    return - (nextsectaddr - memaddr);	/* Next boundary where we can help */
}

/* The function called by target_xfer_memory via our target_ops */

int
exec_xfer_memory (memaddr, myaddr, len, write)
     CORE_ADDR memaddr;
     char *myaddr;
     int len;
     int write;
{
  return xfer_memory (memaddr, myaddr, len, write,
		      exec_bfd, exec_sections, exec_sections_end);
}

/*
 * exec_files_info -	"info files" command processor
 */
static void
exec_files_info() {
	register struct vmap *vp = vmap;

	if (!vp)
		return;

	printf("\tMapping info for file `%s'.\n", vp->name);
	printf("\t  %8.8s   %8.8s %8.8s %s\n"
	       , "start", "end", "section", "file(member)");

	for (; vp; vp = vp->nxt)
		printf("\t0x%8.8x 0x%8.8x %s%s%s%s\n"
		       , vp->tstart
		       , vp->tend
		       , vp->name
		       , *vp->member ? "(" : ""
		       ,  vp->member
		       , *vp->member ? ")" : "");
}

#ifdef DAMON
/*  Damon's implementation of set_section_command! It is based on the sex member
  (which is a section pointer from vmap) of vmap.
  We will not have multiple vmap entries (one for each section), rather transmit
  text and data base offsets and fix them at the same time. Elimination of sex
  entry in vmap make this function obsolute, use the one from exec.c. 
  Need further testing!!	FIXMEmgo.  */

static void
set_section_command(args, from_tty)
char *args; 
{
	register struct vmap *vp = vmap;
	char *secname;
	unsigned seclen;
	unsigned long secaddr;
	char secprint[100];
	long offset;

	if (args == 0)
		error("Must specify section name and its virtual address");

	/* Parse out section name */
	for (secname = args; !isspace(*args); args++)
		;
	seclen = args - secname;

	/* Parse out new virtual address */
	secaddr = parse_and_eval_address(args);

	for (vp = vmap; vp; vp = vp->nxt) {
		if (!strncmp(secname
			     , bfd_section_name(vp->bfd, vp->sex), seclen)
		    && bfd_section_name(vp->bfd, vp->sex)[seclen] == '\0') {
			offset = secaddr - vp->tstart;
			vp->tstart += offset;
			vp->tend   += offset;
			exec_files_info();
			return;
		}
	} 

	if (seclen >= sizeof(secprint))
		seclen = sizeof(secprint) - 1;
	strncpy(secprint, secname, seclen);
	secprint[seclen] = '\0';
	error("Section %s not found", secprint);
}
#else
static void
set_section_command (args, from_tty)
     char *args;
     int from_tty;
{
  struct section_table *p;
  char *secname;
  unsigned seclen;
  unsigned long secaddr;
  char secprint[100];
  long offset;

  if (args == 0)
    error ("Must specify section name and its virtual address");

  /* Parse out section name */
  for (secname = args; !isspace(*args); args++) ;
  seclen = args - secname;

  /* Parse out new virtual address */
  secaddr = parse_and_eval_address (args);

  for (p = exec_sections; p < exec_sections_end; p++) {
    if (!strncmp (secname, bfd_section_name (exec_bfd, p->sec_ptr), seclen)
	&& bfd_section_name (exec_bfd, p->sec_ptr)[seclen] == '\0') {
      offset = secaddr - p->addr;
      p->addr += offset;
      p->endaddr += offset;
      exec_files_info();
      return;
    }
  } 
  if (seclen >= sizeof (secprint))
    seclen = sizeof (secprint) - 1;
  strncpy (secprint, secname, seclen);
  secprint[seclen] = '\0';
  error ("Section %s not found", secprint);
}

#endif /* !DAMON */

struct target_ops exec_ops = {
	"exec", "Local exec file",
	"Use an executable file as a target.\n\
Specify the filename of the executable file.",
	exec_file_command, exec_close, /* open, close */
	child_attach, 0, 0, 0, /* attach, detach, resume, wait, */
	0, 0, /* fetch_registers, store_registers, */
	0, 0, 0, /* prepare_to_store, conv_to, conv_from, */
	exec_xfer_memory, exec_files_info,
	0, 0, /* insert_breakpoint, remove_breakpoint, */
	0, 0, 0, 0, 0, /* terminal stuff */
	0, 0, /* kill, load */
	0, 0, /* call fn, lookup sym */
	child_create_inferior,
	0, /* mourn_inferior */
	file_stratum, 0, /* next */
	0, 1, 0, 0, 0,	/* all mem, mem, stack, regs, exec */
	0, 0,			/* section pointers */
	OPS_MAGIC,		/* Always the last thing */
};


void
_initialize_exec()
{

  add_com("file", class_files, file_command,
	   "Use FILE as program to be debugged.\n\
It is read for its symbols, for getting the contents of pure memory,\n\
and it is the program executed when you use the `run' command.\n\
If FILE cannot be found as specified, your execution directory path\n\
($PATH) is searched for a command of that name.\n\
No arg means to have no executable file and no symbols.");

  add_com("exec-file", class_files, exec_file_command,
	   "Use FILE as program for getting contents of pure memory.\n\
If FILE cannot be found as specified, your execution directory path\n\
is searched for a command of that name.\n\
No arg means have no executable file.");

  add_com("section", class_files, set_section_command,
   "Change the base address of section SECTION of the exec file to ADDR.\n\
This can be used if the exec file does not contain section addresses,\n\
(such as in the a.out format), or when the addresses specified in the\n\
file itself are wrong.  Each section must be changed separately.  The\n\
``info files'' command lists all the sections and their addresses.");

  add_target(&exec_ops);
}