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
|
/* Copyright (C) 2013-2024 Free Software Foundation, Inc.
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 "solib-aix.h"
#include "solib.h"
#include "solist.h"
#include "inferior.h"
#include "gdb_bfd.h"
#include "objfiles.h"
#include "symtab.h"
#include "xcoffread.h"
#include "observable.h"
/* Our private data in struct solib. */
struct lm_info_aix final : public lm_info
{
/* The name of the file mapped by the loader. Apart from the entry
for the main executable, this is usually a shared library (which,
on AIX, is an archive library file, created using the "ar"
command). */
std::string filename;
/* The name of the shared object file with the actual dynamic
loading dependency. This may be empty (Eg. main executable). */
std::string member_name;
/* The address in inferior memory where the text section got mapped. */
CORE_ADDR text_addr = 0;
/* The size of the text section, obtained via the loader data. */
ULONGEST text_size = 0;
/* The address in inferior memory where the data section got mapped. */
CORE_ADDR data_addr = 0;
/* The size of the data section, obtained via the loader data. */
ULONGEST data_size = 0;
};
/* This module's per-inferior data. */
struct solib_aix_inferior_data
{
/* The list of shared libraries.
Note that the first element of this list is always the main
executable, which is not technically a shared library. But
we need that information to perform its relocation, and
the same principles applied to shared libraries also apply
to the main executable. So it's simpler to keep it as part
of this list. */
std::optional<std::vector<lm_info_aix>> library_list;
};
/* Key to our per-inferior data. */
static const registry<inferior>::key<solib_aix_inferior_data>
solib_aix_inferior_data_handle;
/* Return this module's data for the given inferior.
If none is found, add a zero'ed one now. */
static struct solib_aix_inferior_data *
get_solib_aix_inferior_data (struct inferior *inf)
{
struct solib_aix_inferior_data *data;
data = solib_aix_inferior_data_handle.get (inf);
if (data == NULL)
data = solib_aix_inferior_data_handle.emplace (inf);
return data;
}
#if !defined(HAVE_LIBEXPAT)
/* Dummy implementation if XML support is not compiled in. */
static std::optional<std::vector<lm_info_aix>>
solib_aix_parse_libraries (const char *library)
{
static int have_warned;
if (!have_warned)
{
have_warned = 1;
warning (_("Can not parse XML library list; XML support was disabled "
"at compile time"));
}
return {};
}
#else /* HAVE_LIBEXPAT */
#include "xml-support.h"
/* Handle the start of a <library> element. */
static void
library_list_start_library (struct gdb_xml_parser *parser,
const struct gdb_xml_element *element,
void *user_data,
std::vector<gdb_xml_value> &attributes)
{
std::vector<lm_info_aix> *list = (std::vector<lm_info_aix> *) user_data;
lm_info_aix item;
struct gdb_xml_value *attr;
attr = xml_find_attribute (attributes, "name");
item.filename = (const char *) attr->value.get ();
attr = xml_find_attribute (attributes, "member");
if (attr != NULL)
item.member_name = (const char *) attr->value.get ();
attr = xml_find_attribute (attributes, "text_addr");
item.text_addr = * (ULONGEST *) attr->value.get ();
attr = xml_find_attribute (attributes, "text_size");
item.text_size = * (ULONGEST *) attr->value.get ();
attr = xml_find_attribute (attributes, "data_addr");
item.data_addr = * (ULONGEST *) attr->value.get ();
attr = xml_find_attribute (attributes, "data_size");
item.data_size = * (ULONGEST *) attr->value.get ();
list->push_back (std::move (item));
}
/* Handle the start of a <library-list-aix> element. */
static void
library_list_start_list (struct gdb_xml_parser *parser,
const struct gdb_xml_element *element,
void *user_data,
std::vector<gdb_xml_value> &attributes)
{
char *version
= (char *) xml_find_attribute (attributes, "version")->value.get ();
if (strcmp (version, "1.0") != 0)
gdb_xml_error (parser,
_("Library list has unsupported version \"%s\""),
version);
}
/* The allowed elements and attributes for an AIX library list
described in XML format. The root element is a <library-list-aix>. */
static const struct gdb_xml_attribute library_attributes[] =
{
{ "name", GDB_XML_AF_NONE, NULL, NULL },
{ "member", GDB_XML_AF_OPTIONAL, NULL, NULL },
{ "text_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
{ "text_size", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
{ "data_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
{ "data_size", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
{ NULL, GDB_XML_AF_NONE, NULL, NULL }
};
static const struct gdb_xml_element library_list_children[] =
{
{ "library", library_attributes, NULL,
GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
library_list_start_library, NULL},
{ NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};
static const struct gdb_xml_attribute library_list_attributes[] =
{
{ "version", GDB_XML_AF_NONE, NULL, NULL },
{ NULL, GDB_XML_AF_NONE, NULL, NULL }
};
static const struct gdb_xml_element library_list_elements[] =
{
{ "library-list-aix", library_list_attributes, library_list_children,
GDB_XML_EF_NONE, library_list_start_list, NULL },
{ NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};
/* Parse LIBRARY, a string containing the loader info in XML format,
and return a vector of lm_info_aix objects.
Return an empty option if the parsing failed. */
static std::optional<std::vector<lm_info_aix>>
solib_aix_parse_libraries (const char *library)
{
std::vector<lm_info_aix> result;
if (gdb_xml_parse_quick (_("aix library list"), "library-list-aix.dtd",
library_list_elements, library, &result) == 0)
return result;
return {};
}
#endif /* HAVE_LIBEXPAT */
/* Return the loader info for the given inferior (INF), or an empty
option if the list could not be computed.
Cache the result in per-inferior data, so as to avoid recomputing it
each time this function is called.
If an error occurs while computing this list, and WARNING_MSG
is not NULL, then print a warning including WARNING_MSG and
a description of the error. */
static std::optional<std::vector<lm_info_aix>> &
solib_aix_get_library_list (struct inferior *inf, const char *warning_msg)
{
struct solib_aix_inferior_data *data;
/* If already computed, return the cached value. */
data = get_solib_aix_inferior_data (inf);
if (data->library_list.has_value ())
return data->library_list;
std::optional<gdb::char_vector> library_document
= target_read_stralloc (current_inferior ()->top_target (),
TARGET_OBJECT_LIBRARIES_AIX,
NULL);
if (!library_document && warning_msg != NULL)
{
warning (_("%s (failed to read TARGET_OBJECT_LIBRARIES_AIX)"),
warning_msg);
return data->library_list;
}
solib_debug_printf ("TARGET_OBJECT_LIBRARIES_AIX = %s",
library_document->data ());
data->library_list = solib_aix_parse_libraries (library_document->data ());
if (!data->library_list.has_value () && warning_msg != NULL)
warning (_("%s (missing XML support?)"), warning_msg);
return data->library_list;
}
/* If the .bss section's VMA is set to an address located before
the end of the .data section, causing the two sections to overlap,
return the overlap in bytes. Otherwise, return zero.
Motivation:
The GNU linker sometimes sets the start address of the .bss session
before the end of the .data section, making the 2 sections overlap.
The loader appears to handle this situation gracefully, by simply
loading the bss section right after the end of the .data section.
This means that the .data and the .bss sections are sometimes
no longer relocated by the same amount. The problem is that
the ldinfo data does not contain any information regarding
the relocation of the .bss section, assuming that it would be
identical to the information provided for the .data section
(this is what would normally happen if the program was linked
correctly).
GDB therefore needs to detect those cases, and make the corresponding
adjustment to the .bss section offset computed from the ldinfo data
when necessary. This function returns the adjustment amount (or
zero when no adjustment is needed). */
static CORE_ADDR
solib_aix_bss_data_overlap (bfd *abfd)
{
struct bfd_section *data_sect, *bss_sect;
data_sect = bfd_get_section_by_name (abfd, ".data");
if (data_sect == NULL)
return 0; /* No overlap possible. */
bss_sect = bfd_get_section_by_name (abfd, ".bss");
if (bss_sect == NULL)
return 0; /* No overlap possible. */
/* Assume the problem only occurs with linkers that place the .bss
section after the .data section (the problem has only been
observed when using the GNU linker, and the default linker
script always places the .data and .bss sections in that order). */
if (bfd_section_vma (bss_sect) < bfd_section_vma (data_sect))
return 0;
if (bfd_section_vma (bss_sect)
< bfd_section_vma (data_sect) + bfd_section_size (data_sect))
return (bfd_section_vma (data_sect) + bfd_section_size (data_sect)
- bfd_section_vma (bss_sect));
return 0;
}
/* Implement the "relocate_section_addresses" solib_ops method. */
static void
solib_aix_relocate_section_addresses (solib &so, target_section *sec)
{
struct bfd_section *bfd_sect = sec->the_bfd_section;
bfd *abfd = bfd_sect->owner;
const char *section_name = bfd_section_name (bfd_sect);
auto *info = gdb::checked_static_cast<lm_info_aix *> (so.lm_info.get ());
if (strcmp (section_name, ".text") == 0)
{
sec->addr = info->text_addr;
sec->endaddr = sec->addr + info->text_size;
/* The text address given to us by the loader contains
XCOFF headers, so we need to adjust by this much. */
sec->addr += bfd_sect->filepos;
}
else if (strcmp (section_name, ".data") == 0)
{
sec->addr = info->data_addr;
sec->endaddr = sec->addr + info->data_size;
}
else if (strcmp (section_name, ".bss") == 0)
{
/* The information provided by the loader does not include
the address of the .bss section, but we know that it gets
relocated by the same offset as the .data section. So,
compute the relocation offset for the .data section, and
apply it to the .bss section as well. If the .data section
is not defined (which seems highly unlikely), do our best
by assuming no relocation. */
struct bfd_section *data_sect
= bfd_get_section_by_name (abfd, ".data");
CORE_ADDR data_offset = 0;
if (data_sect != NULL)
data_offset = info->data_addr - bfd_section_vma (data_sect);
sec->addr = bfd_section_vma (bfd_sect) + data_offset;
sec->addr += solib_aix_bss_data_overlap (abfd);
sec->endaddr = sec->addr + bfd_section_size (bfd_sect);
}
else
{
/* All other sections should not be relocated. */
sec->addr = bfd_section_vma (bfd_sect);
sec->endaddr = sec->addr + bfd_section_size (bfd_sect);
}
}
/* Compute and return the OBJFILE's section_offset array, using
the associated loader info (INFO). */
static section_offsets
solib_aix_get_section_offsets (struct objfile *objfile,
lm_info_aix *info)
{
bfd *abfd = objfile->obfd.get ();
section_offsets offsets (objfile->section_offsets.size ());
/* .text */
if (objfile->sect_index_text != -1)
{
struct bfd_section *sect
= objfile->sections_start[objfile->sect_index_text].the_bfd_section;
offsets[objfile->sect_index_text]
= info->text_addr + sect->filepos - bfd_section_vma (sect);
}
/* .data */
if (objfile->sect_index_data != -1)
{
struct bfd_section *sect
= objfile->sections_start[objfile->sect_index_data].the_bfd_section;
offsets[objfile->sect_index_data]
= info->data_addr - bfd_section_vma (sect);
}
/* .bss
The offset of the .bss section should be identical to the offset
of the .data section. If no .data section (which seems hard to
believe it is possible), assume it is zero. */
if (objfile->sect_index_bss != -1
&& objfile->sect_index_data != -1)
{
offsets[objfile->sect_index_bss]
= (offsets[objfile->sect_index_data]
+ solib_aix_bss_data_overlap (abfd));
}
/* All other sections should not need relocation. */
return offsets;
}
/* Implement the "solib_create_inferior_hook" solib_ops method. */
static void
solib_aix_solib_create_inferior_hook (int from_tty)
{
const char *warning_msg = "unable to relocate main executable";
/* We need to relocate the main executable... */
std::optional<std::vector<lm_info_aix>> &library_list
= solib_aix_get_library_list (current_inferior (), warning_msg);
if (!library_list.has_value ())
return; /* Warning already printed. */
if (library_list->empty ())
{
warning (_("unable to relocate main executable (no info from loader)"));
return;
}
lm_info_aix &exec_info = (*library_list)[0];
if (current_program_space->symfile_object_file != NULL)
{
objfile *objf = current_program_space->symfile_object_file;
section_offsets offsets = solib_aix_get_section_offsets (objf,
&exec_info);
objfile_relocate (objf, offsets);
}
}
/* Implement the "current_sos" solib_ops method. */
static intrusive_list<solib>
solib_aix_current_sos ()
{
std::optional<std::vector<lm_info_aix>> &library_list
= solib_aix_get_library_list (current_inferior (), NULL);
if (!library_list.has_value ())
return {};
intrusive_list<solib> sos;
/* Build a struct solib for each entry on the list.
We skip the first entry, since this is the entry corresponding
to the main executable, not a shared library. */
for (int ix = 1; ix < library_list->size (); ix++)
{
solib *new_solib = new solib;
std::string so_name;
lm_info_aix &info = (*library_list)[ix];
if (info.member_name.empty ())
{
/* INFO.FILENAME is probably not an archive, but rather
a shared object. Unusual, but it should be possible
to link a program against a shared object directory,
without having to put it in an archive first. */
so_name = info.filename;
}
else
{
/* This is the usual case on AIX, where the shared object
is a member of an archive. Create a synthetic so_name
that follows the same convention as AIX's ldd tool
(Eg: "/lib/libc.a(shr.o)"). */
so_name = string_printf ("%s(%s)", info.filename.c_str (),
info.member_name.c_str ());
}
new_solib->so_original_name = so_name;
new_solib->so_name = so_name;
new_solib->lm_info = std::make_unique<lm_info_aix> (info);
/* Add it to the list. */
sos.push_back (*new_solib);
}
return sos;
}
/* Implement the "open_symbol_file_object" solib_ops method. */
static int
solib_aix_open_symbol_file_object (int from_tty)
{
return 0;
}
/* Implement the "in_dynsym_resolve_code" solib_ops method. */
static int
solib_aix_in_dynsym_resolve_code (CORE_ADDR pc)
{
return 0;
}
/* Implement the "bfd_open" solib_ops method. */
static gdb_bfd_ref_ptr
solib_aix_bfd_open (const char *pathname)
{
/* The pathname is actually a synthetic filename with the following
form: "/path/to/sharedlib(member.o)" (double-quotes excluded).
split this into archive name and member name.
FIXME: This is a little hacky. Perhaps we should provide access
to the solib's lm_info here? */
const int path_len = strlen (pathname);
const char *sep;
int filename_len;
int found_file;
if (pathname[path_len - 1] != ')')
return solib_bfd_open (pathname);
/* Search for the associated parens. */
sep = strrchr (pathname, '(');
if (sep == NULL)
{
/* Should never happen, but recover as best as we can (trying
to open pathname without decoding, possibly leading to
a failure), rather than triggering an assert failure). */
warning (_("missing '(' in shared object pathname: %s"), pathname);
return solib_bfd_open (pathname);
}
filename_len = sep - pathname;
std::string filename (string_printf ("%.*s", filename_len, pathname));
std::string member_name (string_printf ("%.*s", path_len - filename_len - 2,
sep + 1));
/* Calling solib_find makes certain that sysroot path is set properly
if program has a dependency on .a archive and sysroot is set via
set sysroot command. */
gdb::unique_xmalloc_ptr<char> found_pathname
= solib_find (filename.c_str (), &found_file);
if (found_pathname == NULL)
perror_with_name (pathname);
gdb_bfd_ref_ptr archive_bfd (solib_bfd_fopen (found_pathname.get (),
found_file));
if (archive_bfd == NULL)
{
warning (_("Could not open `%s' as an executable file: %s"),
filename.c_str (), bfd_errmsg (bfd_get_error ()));
return NULL;
}
if (bfd_check_format (archive_bfd.get (), bfd_object))
return archive_bfd;
if (! bfd_check_format (archive_bfd.get (), bfd_archive))
{
warning (_("\"%s\": not in executable format: %s."),
filename.c_str (), bfd_errmsg (bfd_get_error ()));
return NULL;
}
gdb_bfd_ref_ptr object_bfd
(gdb_bfd_openr_next_archived_file (archive_bfd.get (), NULL));
while (object_bfd != NULL)
{
if (member_name == bfd_get_filename (object_bfd.get ()))
break;
std::string s = bfd_get_filename (object_bfd.get ());
/* For every inferior after first int bfd system we
will have the pathname instead of the member name
registered. Hence the below condition exists. */
if (s.find ('(') != std::string::npos)
{
int pos = s.find ('(');
int len = s.find (')') - s.find ('(');
if (s.substr (pos+1, len-1) == member_name)
return object_bfd;
}
object_bfd = gdb_bfd_openr_next_archived_file (archive_bfd.get (),
object_bfd.get ());
}
if (object_bfd == NULL)
{
warning (_("\"%s\": member \"%s\" missing."), filename.c_str (),
member_name.c_str ());
return NULL;
}
if (! bfd_check_format (object_bfd.get (), bfd_object))
{
warning (_("%s(%s): not in object format: %s."),
filename.c_str (), member_name.c_str (),
bfd_errmsg (bfd_get_error ()));
return NULL;
}
/* Override the returned bfd's name with the name returned from solib_find
along with appended parenthesized member name in order to allow commands
listing all shared libraries to display. Otherwise, we would only be
displaying the name of the archive member object. */
std::string fname = string_printf ("%s%s",
bfd_get_filename (archive_bfd.get ()),
sep);
bfd_set_filename (object_bfd.get (), fname.c_str ());
return object_bfd;
}
/* Return the obj_section corresponding to OBJFILE's data section,
or NULL if not found. */
/* FIXME: Define in a more general location? */
static struct obj_section *
data_obj_section_from_objfile (struct objfile *objfile)
{
for (obj_section *osect : objfile->sections ())
if (strcmp (bfd_section_name (osect->the_bfd_section), ".data") == 0)
return osect;
return NULL;
}
/* Return the TOC value corresponding to the given PC address,
or raise an error if the value could not be determined. */
CORE_ADDR
solib_aix_get_toc_value (CORE_ADDR pc)
{
struct obj_section *pc_osect = find_pc_section (pc);
struct obj_section *data_osect;
CORE_ADDR result;
if (pc_osect == NULL)
error (_("unable to find TOC entry for pc %s "
"(no section contains this PC)"),
core_addr_to_string (pc));
data_osect = data_obj_section_from_objfile (pc_osect->objfile);
if (data_osect == NULL)
error (_("unable to find TOC entry for pc %s "
"(%s has no data section)"),
core_addr_to_string (pc), objfile_name (pc_osect->objfile));
result = data_osect->addr () + xcoff_get_toc_offset (pc_osect->objfile);
solib_debug_printf ("pc=%s -> %s", core_addr_to_string (pc),
core_addr_to_string (result));
return result;
}
/* This module's normal_stop observer. */
static void
solib_aix_normal_stop_observer (struct bpstat *unused_1, int unused_2)
{
struct solib_aix_inferior_data *data
= get_solib_aix_inferior_data (current_inferior ());
/* The inferior execution has been resumed, and it just stopped
again. This means that the list of shared libraries may have
evolved. Reset our cached value. */
data->library_list.reset ();
}
/* The solib_ops for AIX targets. */
const solib_ops solib_aix_so_ops =
{
solib_aix_relocate_section_addresses,
nullptr,
nullptr,
solib_aix_solib_create_inferior_hook,
solib_aix_current_sos,
solib_aix_open_symbol_file_object,
solib_aix_in_dynsym_resolve_code,
solib_aix_bfd_open,
};
void _initialize_solib_aix ();
void
_initialize_solib_aix ()
{
gdb::observers::normal_stop.attach (solib_aix_normal_stop_observer,
"solib-aix");
}
|