aboutsummaryrefslogtreecommitdiff
path: root/gdb/solib-irix.c
blob: 1cec28202153872724fd870f077e4eae123fd511 (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
/* Shared library support for IRIX.
   Copyright (C) 1993-1996, 1998-2002, 2004, 2007-2012 Free Software
   Foundation, Inc.

   This file was created using portions of irix5-nat.c originally
   contributed to GDB by Ian Lance Taylor.

   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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "symtab.h"
#include "bfd.h"
/* FIXME: ezannoni/2004-02-13 Verify that the include below is
   really needed.  */
#include "symfile.h"
#include "objfiles.h"
#include "gdbcore.h"
#include "target.h"
#include "inferior.h"
#include "gdbthread.h"

#include "solist.h"
#include "solib.h"
#include "solib-irix.h"


/* Link map info to include in an allocate so_list entry.  Unlike some
   of the other solib backends, this (Irix) backend chooses to decode
   the link map info obtained from the target and store it as (mostly)
   CORE_ADDRs which need no further decoding.  This is more convenient
   because there are three different link map formats to worry about.
   We use a single routine (fetch_lm_info) to read (and decode) the target
   specific link map data.  */

struct lm_info
{
  CORE_ADDR addr;		/* address of obj_info or obj_list
				   struct on target (from which the
				   following information is obtained).  */
  CORE_ADDR next;		/* address of next item in list.  */
  CORE_ADDR reloc_offset;	/* amount to relocate by  */
  CORE_ADDR pathname_addr;	/* address of pathname  */
  int pathname_len;		/* length of pathname */
};

/* It's not desirable to use the system header files to obtain the
   structure of the obj_list or obj_info structs.  Therefore, we use a
   platform neutral representation which has been derived from the IRIX
   header files.  */

typedef struct
{
  gdb_byte b[4];
}
gdb_int32_bytes;
typedef struct
{
  gdb_byte b[8];
}
gdb_int64_bytes;

/* The "old" obj_list struct.  This is used with old (o32) binaries.
   The ``data'' member points at a much larger and more complicated
   struct which we will only refer to by offsets.  See
   fetch_lm_info().  */

struct irix_obj_list
{
  gdb_int32_bytes data;
  gdb_int32_bytes next;
  gdb_int32_bytes prev;
};

/* The ELF32 and ELF64 versions of the above struct.  The oi_magic value
   corresponds to the ``data'' value in the "old" struct.  When this value
   is 0xffffffff, the data will be in one of the following formats.  The
   ``oi_size'' field is used to decide which one we actually have.  */

struct irix_elf32_obj_info
{
  gdb_int32_bytes oi_magic;
  gdb_int32_bytes oi_size;
  gdb_int32_bytes oi_next;
  gdb_int32_bytes oi_prev;
  gdb_int32_bytes oi_ehdr;
  gdb_int32_bytes oi_orig_ehdr;
  gdb_int32_bytes oi_pathname;
  gdb_int32_bytes oi_pathname_len;
};

struct irix_elf64_obj_info
{
  gdb_int32_bytes oi_magic;
  gdb_int32_bytes oi_size;
  gdb_int64_bytes oi_next;
  gdb_int64_bytes oi_prev;
  gdb_int64_bytes oi_ehdr;
  gdb_int64_bytes oi_orig_ehdr;
  gdb_int64_bytes oi_pathname;
  gdb_int32_bytes oi_pathname_len;
  gdb_int32_bytes padding;
};

/* Union of all of the above (plus a split out magic field).  */

union irix_obj_info
{
  gdb_int32_bytes magic;
  struct irix_obj_list ol32;
  struct irix_elf32_obj_info oi32;
  struct irix_elf64_obj_info oi64;
};

/* MIPS sign extends its 32 bit addresses.  We could conceivably use
   extract_typed_address here, but to do so, we'd have to construct an
   appropriate type.  Calling extract_signed_integer seems simpler.  */

static CORE_ADDR
extract_mips_address (void *addr, int len, enum bfd_endian byte_order)
{
  return extract_signed_integer (addr, len, byte_order);
}

/* Fetch and return the link map data associated with ADDR.  Note that
   this routine automatically determines which (of three) link map
   formats is in use by the target.  */

static struct lm_info
fetch_lm_info (CORE_ADDR addr)
{
  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
  struct lm_info li;
  union irix_obj_info buf;

  li.addr = addr;

  /* The smallest region that we'll need is for buf.ol32.  We'll read
     that first.  We'll read more of the buffer later if we have to deal
     with one of the other cases.  (We don't want to incur a memory error
     if we were to read a larger region that generates an error due to
     being at the end of a page or the like.)  */
  read_memory (addr, (char *) &buf, sizeof (buf.ol32));

  if (extract_unsigned_integer (buf.magic.b, sizeof (buf.magic), byte_order)
      != 0xffffffff)
    {
      /* Use buf.ol32...  */
      char obj_buf[432];
      CORE_ADDR obj_addr = extract_mips_address (&buf.ol32.data,
						 sizeof (buf.ol32.data),
						 byte_order);

      li.next = extract_mips_address (&buf.ol32.next,
				      sizeof (buf.ol32.next), byte_order);

      read_memory (obj_addr, obj_buf, sizeof (obj_buf));

      li.pathname_addr = extract_mips_address (&obj_buf[236], 4, byte_order);
      li.pathname_len = 0;	/* unknown */
      li.reloc_offset = extract_mips_address (&obj_buf[196], 4, byte_order)
	- extract_mips_address (&obj_buf[248], 4, byte_order);

    }
  else if (extract_unsigned_integer (buf.oi32.oi_size.b,
				     sizeof (buf.oi32.oi_size), byte_order)
	   == sizeof (buf.oi32))
    {
      /* Use buf.oi32...  */

      /* Read rest of buffer.  */
      read_memory (addr + sizeof (buf.ol32),
		   ((char *) &buf) + sizeof (buf.ol32),
		   sizeof (buf.oi32) - sizeof (buf.ol32));

      /* Fill in fields using buffer contents.  */
      li.next = extract_mips_address (&buf.oi32.oi_next,
				      sizeof (buf.oi32.oi_next), byte_order);
      li.reloc_offset = extract_mips_address (&buf.oi32.oi_ehdr,
					      sizeof (buf.oi32.oi_ehdr),
					      byte_order)
	- extract_mips_address (&buf.oi32.oi_orig_ehdr,
				sizeof (buf.oi32.oi_orig_ehdr), byte_order);
      li.pathname_addr = extract_mips_address (&buf.oi32.oi_pathname,
					       sizeof (buf.oi32.oi_pathname),
					       byte_order);
      li.pathname_len = extract_unsigned_integer (buf.oi32.oi_pathname_len.b,
						  sizeof (buf.oi32.
							  oi_pathname_len),
						  byte_order);
    }
  else if (extract_unsigned_integer (buf.oi64.oi_size.b,
				     sizeof (buf.oi64.oi_size), byte_order)
	   == sizeof (buf.oi64))
    {
      /* Use buf.oi64...  */

      /* Read rest of buffer.  */
      read_memory (addr + sizeof (buf.ol32),
		   ((char *) &buf) + sizeof (buf.ol32),
		   sizeof (buf.oi64) - sizeof (buf.ol32));

      /* Fill in fields using buffer contents.  */
      li.next = extract_mips_address (&buf.oi64.oi_next,
				      sizeof (buf.oi64.oi_next), byte_order);
      li.reloc_offset = extract_mips_address (&buf.oi64.oi_ehdr,
					      sizeof (buf.oi64.oi_ehdr),
					      byte_order)
	- extract_mips_address (&buf.oi64.oi_orig_ehdr,
				sizeof (buf.oi64.oi_orig_ehdr), byte_order);
      li.pathname_addr = extract_mips_address (&buf.oi64.oi_pathname,
					       sizeof (buf.oi64.oi_pathname),
					       byte_order);
      li.pathname_len = extract_unsigned_integer (buf.oi64.oi_pathname_len.b,
						  sizeof (buf.oi64.
							  oi_pathname_len),
						  byte_order);
    }
  else
    {
      error (_("Unable to fetch shared library obj_info or obj_list info."));
    }

  return li;
}

/* The symbol which starts off the list of shared libraries.  */
#define DEBUG_BASE "__rld_obj_head"

static void *base_breakpoint;

static CORE_ADDR debug_base;	/* Base of dynamic linker structures.  */

/* Locate the base address of dynamic linker structs.

   For both the SunOS and SVR4 shared library implementations, if the
   inferior executable has been linked dynamically, there is a single
   address somewhere in the inferior's data space which is the key to
   locating all of the dynamic linker's runtime structures.  This
   address is the value of the symbol defined by the macro DEBUG_BASE.
   The job of this function is to find and return that address, or to
   return 0 if there is no such address (the executable is statically
   linked for example).

   For SunOS, the job is almost trivial, since the dynamic linker and
   all of it's structures are statically linked to the executable at
   link time.  Thus the symbol for the address we are looking for has
   already been added to the minimal symbol table for the executable's
   objfile at the time the symbol file's symbols were read, and all we
   have to do is look it up there.  Note that we explicitly do NOT want
   to find the copies in the shared library.

   The SVR4 version is much more complicated because the dynamic linker
   and it's structures are located in the shared C library, which gets
   run as the executable's "interpreter" by the kernel.  We have to go
   to a lot more work to discover the address of DEBUG_BASE.  Because
   of this complexity, we cache the value we find and return that value
   on subsequent invocations.  Note there is no copy in the executable
   symbol tables.

   Irix 5 is basically like SunOS.

   Note that we can assume nothing about the process state at the time
   we need to find this address.  We may be stopped on the first instruc-
   tion of the interpreter (C shared library), the first instruction of
   the executable itself, or somewhere else entirely (if we attached
   to the process for example).  */

static CORE_ADDR
locate_base (void)
{
  struct minimal_symbol *msymbol;
  CORE_ADDR address = 0;

  msymbol = lookup_minimal_symbol (DEBUG_BASE, NULL, symfile_objfile);
  if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
    {
      address = SYMBOL_VALUE_ADDRESS (msymbol);
    }
  return (address);
}

/* Remove the "mapping changed" breakpoint.

   Removes the breakpoint that gets hit when the dynamic linker
   completes a mapping change.  */

static int
disable_break (void)
{
  int status = 1;

  /* Note that breakpoint address and original contents are in our address
     space, so we just need to write the original contents back.  */

  if (deprecated_remove_raw_breakpoint (target_gdbarch, base_breakpoint) != 0)
    {
      status = 0;
    }

  base_breakpoint = NULL;

  /* Note that it is possible that we have stopped at a location that
     is different from the location where we inserted our breakpoint.
     On mips-irix, we can actually land in __dbx_init(), so we should
     not check the PC against our breakpoint address here.  See procfs.c
     for more details.  */

  return (status);
}

/* Arrange for dynamic linker to hit breakpoint.

   This functions inserts a breakpoint at the entry point of the
   main executable, where all shared libraries are mapped in.  */

static int
enable_break (void)
{
  if (symfile_objfile != NULL && has_stack_frames ())
    {
      struct frame_info *frame = get_current_frame ();
      struct address_space *aspace = get_frame_address_space (frame);
      CORE_ADDR entry_point;

      if (!entry_point_address_query (&entry_point))
	return 0;

      base_breakpoint = deprecated_insert_raw_breakpoint (target_gdbarch,
							  aspace, entry_point);

      if (base_breakpoint != NULL)
	return 1;
    }

  return 0;
}

/* Implement the "create_inferior_hook" target_solib_ops method.

   For SunOS executables, this first instruction is typically the
   one at "_start", or a similar text label, regardless of whether
   the executable is statically or dynamically linked.  The runtime
   startup code takes care of dynamically linking in any shared
   libraries, once gdb allows the inferior to continue.

   For SVR4 executables, this first instruction is either the first
   instruction in the dynamic linker (for dynamically linked
   executables) or the instruction at "start" for statically linked
   executables.  For dynamically linked executables, the system
   first exec's /lib/libc.so.N, which contains the dynamic linker,
   and starts it running.  The dynamic linker maps in any needed
   shared libraries, maps in the actual user executable, and then
   jumps to "start" in the user executable.

   For both SunOS shared libraries, and SVR4 shared libraries, we
   can arrange to cooperate with the dynamic linker to discover the
   names of shared libraries that are dynamically linked, and the
   base addresses to which they are linked.

   This function is responsible for discovering those names and
   addresses, and saving sufficient information about them to allow
   their symbols to be read at a later time.

   FIXME

   Between enable_break() and disable_break(), this code does not
   properly handle hitting breakpoints which the user might have
   set in the startup code or in the dynamic linker itself.  Proper
   handling will probably have to wait until the implementation is
   changed to use the "breakpoint handler function" method.

   Also, what if child has exit()ed?  Must exit loop somehow.  */

static void
irix_solib_create_inferior_hook (int from_tty)
{
  struct inferior *inf;
  struct thread_info *tp;

  inf = current_inferior ();

  /* If we are attaching to the inferior, the shared libraries
     have already been mapped, so nothing more to do.  */
  if (inf->attach_flag)
    return;

  /* Likewise when debugging from a core file, the shared libraries
     have already been mapped, so nothing more to do.  */
  if (!target_can_run (&current_target))
    return;

  if (!enable_break ())
    {
      warning (_("shared library handler failed to enable breakpoint"));
      return;
    }

  /* Now run the target.  It will eventually hit the breakpoint, at
     which point all of the libraries will have been mapped in and we
     can go groveling around in the dynamic linker structures to find
     out what we need to know about them.  */

  tp = inferior_thread ();

  clear_proceed_status ();

  inf->control.stop_soon = STOP_QUIETLY;
  tp->suspend.stop_signal = GDB_SIGNAL_0;

  do
    {
      target_resume (pid_to_ptid (-1), 0, tp->suspend.stop_signal);
      wait_for_inferior ();
    }
  while (tp->suspend.stop_signal != GDB_SIGNAL_TRAP);

  /* We are now either at the "mapping complete" breakpoint (or somewhere
     else, a condition we aren't prepared to deal with anyway), so adjust
     the PC as necessary after a breakpoint, disable the breakpoint, and
     add any shared libraries that were mapped in.  */

  if (!disable_break ())
    {
      warning (_("shared library handler failed to disable breakpoint"));
    }

  /* solib_add will call reinit_frame_cache.
     But we are stopped in the startup code and we might not have symbols
     for the startup code, so heuristic_proc_start could be called
     and will put out an annoying warning.
     Delaying the resetting of stop_soon until after symbol loading
     suppresses the warning.  */
  solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
  inf->control.stop_soon = NO_STOP_QUIETLY;
}

/* Implement the "current_sos" target_so_ops method.  */

static struct so_list *
irix_current_sos (void)
{
  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
  int addr_size = gdbarch_addr_bit (target_gdbarch) / TARGET_CHAR_BIT;
  CORE_ADDR lma;
  char addr_buf[8];
  struct so_list *head = 0;
  struct so_list **link_ptr = &head;
  int is_first = 1;
  struct lm_info lm;

  /* Make sure we've looked up the inferior's dynamic linker's base
     structure.  */
  if (!debug_base)
    {
      debug_base = locate_base ();

      /* If we can't find the dynamic linker's base structure, this
         must not be a dynamically linked executable.  Hmm.  */
      if (!debug_base)
	return 0;
    }

  read_memory (debug_base, addr_buf, addr_size);
  lma = extract_mips_address (addr_buf, addr_size, byte_order);

  while (lma)
    {
      lm = fetch_lm_info (lma);
      if (!is_first)
	{
	  int errcode;
	  char *name_buf;
	  int name_size;
	  struct so_list *new
	    = (struct so_list *) xmalloc (sizeof (struct so_list));
	  struct cleanup *old_chain = make_cleanup (xfree, new);

	  memset (new, 0, sizeof (*new));

	  new->lm_info = xmalloc (sizeof (struct lm_info));
	  make_cleanup (xfree, new->lm_info);

	  *new->lm_info = lm;

	  /* Extract this shared object's name.  */
	  name_size = lm.pathname_len;
	  if (name_size == 0)
	    name_size = SO_NAME_MAX_PATH_SIZE - 1;

	  if (name_size >= SO_NAME_MAX_PATH_SIZE)
	    {
	      name_size = SO_NAME_MAX_PATH_SIZE - 1;
	      warning (_("current_sos: truncating name of "
		         "%d characters to only %d characters"),
		       lm.pathname_len, name_size);
	    }

	  target_read_string (lm.pathname_addr, &name_buf,
			      name_size, &errcode);
	  if (errcode != 0)
	    warning (_("Can't read pathname for load map: %s."),
		       safe_strerror (errcode));
	  else
	    {
	      strncpy (new->so_name, name_buf, name_size);
	      new->so_name[name_size] = '\0';
	      xfree (name_buf);
	      strcpy (new->so_original_name, new->so_name);
	    }

	  new->next = 0;
	  *link_ptr = new;
	  link_ptr = &new->next;

	  discard_cleanups (old_chain);
	}
      is_first = 0;
      lma = lm.next;
    }

  return head;
}

/* Implement the "open_symbol_file_object" target_so_ops method.

   If no open symbol file, attempt to locate and open the main symbol
   file.  On IRIX, this is the first link map entry.  If its name is
   here, we can open it.  Useful when attaching to a process without
   first loading its symbol file.  */

static int
irix_open_symbol_file_object (void *from_ttyp)
{
  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
  int addr_size = gdbarch_addr_bit (target_gdbarch) / TARGET_CHAR_BIT;
  CORE_ADDR lma;
  char addr_buf[8];
  struct lm_info lm;
  struct cleanup *cleanups;
  int errcode;
  int from_tty = *(int *) from_ttyp;
  char *filename;

  if (symfile_objfile)
    if (!query (_("Attempt to reload symbols from process? ")))
      return 0;

  if ((debug_base = locate_base ()) == 0)
    return 0;			/* failed somehow...  */

  /* First link map member should be the executable.  */
  read_memory (debug_base, addr_buf, addr_size);
  lma = extract_mips_address (addr_buf, addr_size, byte_order);
  if (lma == 0)
    return 0;			/* failed somehow...  */

  lm = fetch_lm_info (lma);

  if (lm.pathname_addr == 0)
    return 0;			/* No filename.  */

  /* Now fetch the filename from target memory.  */
  target_read_string (lm.pathname_addr, &filename, SO_NAME_MAX_PATH_SIZE - 1,
		      &errcode);

  if (errcode)
    {
      warning (_("failed to read exec filename from attached file: %s"),
	       safe_strerror (errcode));
      return 0;
    }

  cleanups = make_cleanup (xfree, filename);
  /* Have a pathname: read the symbol file.  */
  symbol_file_add_main (filename, from_tty);

  do_cleanups (cleanups);

  return 1;
}

/* Implement the "special_symbol_handling" target_so_ops method.

   For IRIX, there's nothing to do.  */

static void
irix_special_symbol_handling (void)
{
}

/* Using the solist entry SO, relocate the addresses in SEC.  */

static void
irix_relocate_section_addresses (struct so_list *so,
				 struct target_section *sec)
{
  sec->addr += so->lm_info->reloc_offset;
  sec->endaddr += so->lm_info->reloc_offset;
}

/* Free the lm_info struct.  */

static void
irix_free_so (struct so_list *so)
{
  xfree (so->lm_info);
}

/* Clear backend specific state.  */

static void
irix_clear_solib (void)
{
  debug_base = 0;
}

/* Return 1 if PC lies in the dynamic symbol resolution code of the
   run time loader.  */
static int
irix_in_dynsym_resolve_code (CORE_ADDR pc)
{
  return 0;
}

struct target_so_ops irix_so_ops;

/* Provide a prototype to silence -Wmissing-prototypes.  */
extern initialize_file_ftype _initialize_irix_solib;

void
_initialize_irix_solib (void)
{
  irix_so_ops.relocate_section_addresses = irix_relocate_section_addresses;
  irix_so_ops.free_so = irix_free_so;
  irix_so_ops.clear_solib = irix_clear_solib;
  irix_so_ops.solib_create_inferior_hook = irix_solib_create_inferior_hook;
  irix_so_ops.special_symbol_handling = irix_special_symbol_handling;
  irix_so_ops.current_sos = irix_current_sos;
  irix_so_ops.open_symbol_file_object = irix_open_symbol_file_object;
  irix_so_ops.in_dynsym_resolve_code = irix_in_dynsym_resolve_code;
  irix_so_ops.bfd_open = solib_bfd_open;
}