Merge branch 'master' into merge-job
[deliverable/binutils-gdb.git] / gdb / osabi.c
1 /* OS ABI variant handling for GDB.
2
3 Copyright (C) 2001-2020 Free Software Foundation, Inc.
4 Copyright (C) 2019-2020 Advanced Micro Devices, Inc. All rights reserved.
5
6 This file is part of GDB.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20
21 #include "defs.h"
22
23 #include "osabi.h"
24 #include "arch-utils.h"
25 #include "gdbcmd.h"
26 #include "command.h"
27
28 #include "elf-bfd.h"
29
30 #ifndef GDB_OSABI_DEFAULT
31 #define GDB_OSABI_DEFAULT GDB_OSABI_UNKNOWN
32 #endif
33
34 /* State for the "set osabi" command. */
35 static enum { osabi_auto, osabi_default, osabi_user } user_osabi_state;
36 static enum gdb_osabi user_selected_osabi;
37 static const char *gdb_osabi_available_names[GDB_OSABI_INVALID + 3] = {
38 "auto",
39 "default",
40 "none",
41 NULL
42 };
43 static const char *set_osabi_string;
44
45 /* Names associated with each osabi. */
46
47 struct osabi_names
48 {
49 /* The "pretty" name. */
50
51 const char *pretty;
52
53 /* The triplet regexp, or NULL if not known. */
54
55 const char *regexp;
56 };
57
58 /* This table matches the indices assigned to enum gdb_osabi. Keep
59 them in sync. */
60 static const struct osabi_names gdb_osabi_names[] =
61 {
62 { "unknown", NULL },
63 { "none", NULL },
64
65 { "SVR4", NULL },
66 { "GNU/Hurd", NULL },
67 { "Solaris", NULL },
68 { "GNU/Linux", "linux(-gnu[^-]*)?" },
69 { "FreeBSD", NULL },
70 { "NetBSD", NULL },
71 { "OpenBSD", NULL },
72 { "WindowsCE", NULL },
73 { "DJGPP", NULL },
74 { "QNX-Neutrino", NULL },
75 { "Cygwin", NULL },
76 { "AIX", NULL },
77 { "DICOS", NULL },
78 { "Darwin", NULL },
79 { "Symbian", NULL },
80 { "OpenVMS", NULL },
81 { "LynxOS178", NULL },
82 { "Newlib", NULL },
83 { "SDE", NULL },
84 { "PikeOS", NULL },
85 { "AMD HSA Runtime" },
86
87 { "<invalid>", NULL }
88 };
89
90 const char *
91 gdbarch_osabi_name (enum gdb_osabi osabi)
92 {
93 if (osabi >= GDB_OSABI_UNKNOWN && osabi < GDB_OSABI_INVALID)
94 return gdb_osabi_names[osabi].pretty;
95
96 return gdb_osabi_names[GDB_OSABI_INVALID].pretty;
97 }
98
99 /* See osabi.h. */
100
101 const char *
102 osabi_triplet_regexp (enum gdb_osabi osabi)
103 {
104 if (osabi >= GDB_OSABI_UNKNOWN && osabi < GDB_OSABI_INVALID)
105 return gdb_osabi_names[osabi].regexp;
106
107 return gdb_osabi_names[GDB_OSABI_INVALID].regexp;
108 }
109
110 /* Lookup the OS ABI corresponding to the specified target description
111 string. */
112
113 enum gdb_osabi
114 osabi_from_tdesc_string (const char *name)
115 {
116 int i;
117
118 for (i = 0; i < ARRAY_SIZE (gdb_osabi_names); i++)
119 if (strcmp (name, gdb_osabi_names[i].pretty) == 0)
120 {
121 /* See note above: the name table matches the indices assigned
122 to enum gdb_osabi. */
123 enum gdb_osabi osabi = (enum gdb_osabi) i;
124
125 if (osabi == GDB_OSABI_INVALID)
126 return GDB_OSABI_UNKNOWN;
127 else
128 return osabi;
129 }
130
131 return GDB_OSABI_UNKNOWN;
132 }
133
134 /* Handler for a given architecture/OS ABI pair. There should be only
135 one handler for a given OS ABI each architecture family. */
136 struct gdb_osabi_handler
137 {
138 struct gdb_osabi_handler *next;
139 const struct bfd_arch_info *arch_info;
140 enum gdb_osabi osabi;
141 void (*init_osabi)(struct gdbarch_info, struct gdbarch *);
142 };
143
144 static struct gdb_osabi_handler *gdb_osabi_handler_list;
145
146 void
147 gdbarch_register_osabi (enum bfd_architecture arch, unsigned long machine,
148 enum gdb_osabi osabi,
149 void (*init_osabi)(struct gdbarch_info,
150 struct gdbarch *))
151 {
152 struct gdb_osabi_handler **handler_p;
153 const struct bfd_arch_info *arch_info = bfd_lookup_arch (arch, machine);
154 const char **name_ptr;
155
156 /* Registering an OS ABI handler for "unknown" is not allowed. */
157 if (osabi == GDB_OSABI_UNKNOWN)
158 {
159 internal_error
160 (__FILE__, __LINE__,
161 _("gdbarch_register_osabi: An attempt to register a handler for "
162 "OS ABI \"%s\" for architecture %s was made. The handler will "
163 "not be registered"),
164 gdbarch_osabi_name (osabi),
165 bfd_printable_arch_mach (arch, machine));
166 return;
167 }
168
169 gdb_assert (arch_info);
170
171 for (handler_p = &gdb_osabi_handler_list; *handler_p != NULL;
172 handler_p = &(*handler_p)->next)
173 {
174 if ((*handler_p)->arch_info == arch_info
175 && (*handler_p)->osabi == osabi)
176 {
177 internal_error
178 (__FILE__, __LINE__,
179 _("gdbarch_register_osabi: A handler for OS ABI \"%s\" "
180 "has already been registered for architecture %s"),
181 gdbarch_osabi_name (osabi),
182 arch_info->printable_name);
183 /* If user wants to continue, override previous definition. */
184 (*handler_p)->init_osabi = init_osabi;
185 return;
186 }
187 }
188
189 (*handler_p) = XNEW (struct gdb_osabi_handler);
190 (*handler_p)->next = NULL;
191 (*handler_p)->arch_info = arch_info;
192 (*handler_p)->osabi = osabi;
193 (*handler_p)->init_osabi = init_osabi;
194
195 /* Add this OS ABI to the list of enum values for "set osabi", if it isn't
196 already there. */
197 for (name_ptr = gdb_osabi_available_names; *name_ptr; name_ptr ++)
198 {
199 if (*name_ptr == gdbarch_osabi_name (osabi))
200 return;
201 }
202 *name_ptr++ = gdbarch_osabi_name (osabi);
203 *name_ptr = NULL;
204 }
205 \f
206
207 /* Sniffer to find the OS ABI for a given file's architecture and flavour.
208 It is legal to have multiple sniffers for each arch/flavour pair, to
209 disambiguate one OS's a.out from another, for example. The first sniffer
210 to return something other than GDB_OSABI_UNKNOWN wins, so a sniffer should
211 be careful to claim a file only if it knows for sure what it is. */
212 struct gdb_osabi_sniffer
213 {
214 struct gdb_osabi_sniffer *next;
215 enum bfd_architecture arch; /* bfd_arch_unknown == wildcard */
216 enum bfd_flavour flavour;
217 enum gdb_osabi (*sniffer)(bfd *);
218 };
219
220 static struct gdb_osabi_sniffer *gdb_osabi_sniffer_list;
221
222 void
223 gdbarch_register_osabi_sniffer (enum bfd_architecture arch,
224 enum bfd_flavour flavour,
225 enum gdb_osabi (*sniffer_fn)(bfd *))
226 {
227 struct gdb_osabi_sniffer *sniffer;
228
229 sniffer = XNEW (struct gdb_osabi_sniffer);
230 sniffer->arch = arch;
231 sniffer->flavour = flavour;
232 sniffer->sniffer = sniffer_fn;
233
234 sniffer->next = gdb_osabi_sniffer_list;
235 gdb_osabi_sniffer_list = sniffer;
236 }
237 \f
238
239 enum gdb_osabi
240 gdbarch_lookup_osabi (bfd *abfd)
241 {
242 struct gdb_osabi_sniffer *sniffer;
243 enum gdb_osabi osabi, match;
244 int match_specific;
245
246 /* If we aren't in "auto" mode, return the specified OS ABI. */
247 if (user_osabi_state == osabi_user)
248 return user_selected_osabi;
249
250 /* If we don't have a binary, just return unknown. The caller may
251 have other sources the OSABI can be extracted from, e.g., the
252 target description. */
253 if (abfd == NULL)
254 return GDB_OSABI_UNKNOWN;
255
256 match = GDB_OSABI_UNKNOWN;
257 match_specific = 0;
258
259 for (sniffer = gdb_osabi_sniffer_list; sniffer != NULL;
260 sniffer = sniffer->next)
261 {
262 if ((sniffer->arch == bfd_arch_unknown /* wildcard */
263 || sniffer->arch == bfd_get_arch (abfd))
264 && sniffer->flavour == bfd_get_flavour (abfd))
265 {
266 osabi = (*sniffer->sniffer) (abfd);
267 if (osabi < GDB_OSABI_UNKNOWN || osabi >= GDB_OSABI_INVALID)
268 {
269 internal_error
270 (__FILE__, __LINE__,
271 _("gdbarch_lookup_osabi: invalid OS ABI (%d) from sniffer "
272 "for architecture %s flavour %d"),
273 (int) osabi,
274 bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
275 (int) bfd_get_flavour (abfd));
276 }
277 else if (osabi != GDB_OSABI_UNKNOWN)
278 {
279 /* A specific sniffer always overrides a generic sniffer.
280 Croak on multiple match if the two matches are of the
281 same class. If the user wishes to continue, we'll use
282 the first match. */
283 if (match != GDB_OSABI_UNKNOWN)
284 {
285 if ((match_specific && sniffer->arch != bfd_arch_unknown)
286 || (!match_specific && sniffer->arch == bfd_arch_unknown))
287 {
288 internal_error
289 (__FILE__, __LINE__,
290 _("gdbarch_lookup_osabi: multiple %sspecific OS ABI "
291 "match for architecture %s flavour %d: first "
292 "match \"%s\", second match \"%s\""),
293 match_specific ? "" : "non-",
294 bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
295 (int) bfd_get_flavour (abfd),
296 gdbarch_osabi_name (match),
297 gdbarch_osabi_name (osabi));
298 }
299 else if (sniffer->arch != bfd_arch_unknown)
300 {
301 match = osabi;
302 match_specific = 1;
303 }
304 }
305 else
306 {
307 match = osabi;
308 if (sniffer->arch != bfd_arch_unknown)
309 match_specific = 1;
310 }
311 }
312 }
313 }
314
315 return match;
316 }
317
318
319 /* Return non-zero if architecture A can run code written for
320 architecture B. */
321 static int
322 can_run_code_for (const struct bfd_arch_info *a, const struct bfd_arch_info *b)
323 {
324 /* BFD's 'A->compatible (A, B)' functions return zero if A and B are
325 incompatible. But if they are compatible, it returns the 'more
326 featureful' of the two arches. That is, if A can run code
327 written for B, but B can't run code written for A, then it'll
328 return A.
329
330 struct bfd_arch_info objects are singletons: that is, there's
331 supposed to be exactly one instance for a given machine. So you
332 can tell whether two are equivalent by comparing pointers. */
333 return (a == b || a->compatible (a, b) == a);
334 }
335
336
337 void
338 gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
339 {
340 struct gdb_osabi_handler *handler;
341
342 gdb_assert (info.osabi != GDB_OSABI_UNKNOWN);
343
344 for (handler = gdb_osabi_handler_list; handler != NULL;
345 handler = handler->next)
346 {
347 if (handler->osabi != info.osabi)
348 continue;
349
350 /* If the architecture described by ARCH_INFO can run code for
351 the architecture we registered the handler for, then the
352 handler is applicable. Note, though, that if the handler is
353 for an architecture that is a superset of ARCH_INFO, we can't
354 use that --- it would be perfectly correct for it to install
355 gdbarch methods that refer to registers / instructions /
356 other facilities ARCH_INFO doesn't have.
357
358 NOTE: kettenis/20021027: There may be more than one machine
359 type that is compatible with the desired machine type. Right
360 now we simply return the first match, which is fine for now.
361 However, we might want to do something smarter in the future. */
362 /* NOTE: cagney/2003-10-23: The code for "a can_run_code_for b"
363 is implemented using BFD's compatible method (a->compatible
364 (b) == a -- the lowest common denominator between a and b is
365 a). That method's definition of compatible may not be as you
366 expect. For instance the test "amd64 can run code for i386"
367 (or more generally "64-bit ISA can run code for the 32-bit
368 ISA"). BFD doesn't normally consider 32-bit and 64-bit
369 "compatible" so it doesn't succeed. */
370 if (can_run_code_for (info.bfd_arch_info, handler->arch_info))
371 {
372 (*handler->init_osabi) (info, gdbarch);
373 return;
374 }
375 }
376
377 if (info.osabi == GDB_OSABI_NONE)
378 {
379 /* Don't complain about no OSABI. Assume the user knows
380 what they are doing. */
381 return;
382 }
383
384 warning
385 ("A handler for the OS ABI \"%s\" is not built into this configuration\n"
386 "of GDB. Attempting to continue with the default %s settings.\n",
387 gdbarch_osabi_name (info.osabi),
388 info.bfd_arch_info->printable_name);
389 }
390 \f
391 /* Limit on the amount of data to be read. */
392 #define MAX_NOTESZ 128
393
394 /* Return non-zero if NOTE matches NAME, DESCSZ and TYPE. If
395 *SECTSIZE is non-zero, then this reads that many bytes from
396 the start of the section and clears *SECTSIZE. */
397
398 static int
399 check_note (bfd *abfd, asection *sect, char *note, unsigned int *sectsize,
400 const char *name, unsigned long descsz, unsigned long type)
401 {
402 unsigned long notesz;
403
404 if (*sectsize)
405 {
406 if (!bfd_get_section_contents (abfd, sect, note, 0, *sectsize))
407 return 0;
408 *sectsize = 0;
409 }
410
411 /* Calculate the size of this note. */
412 notesz = strlen (name) + 1;
413 notesz = ((notesz + 3) & ~3);
414 notesz += descsz;
415 notesz = ((notesz + 3) & ~3);
416
417 /* If this assertion triggers, increase MAX_NOTESZ. */
418 gdb_assert (notesz <= MAX_NOTESZ);
419
420 /* Check whether SECT is big enough to contain the complete note. */
421 if (notesz > bfd_section_size (sect))
422 return 0;
423
424 /* Check the note name. */
425 if (bfd_h_get_32 (abfd, note) != (strlen (name) + 1)
426 || strcmp (note + 12, name) != 0)
427 return 0;
428
429 /* Check the descriptor size. */
430 if (bfd_h_get_32 (abfd, note + 4) != descsz)
431 return 0;
432
433 /* Check the note type. */
434 if (bfd_h_get_32 (abfd, note + 8) != type)
435 return 0;
436
437 return 1;
438 }
439
440 /* Generic sniffer for ELF flavoured files. */
441
442 void
443 generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, void *obj)
444 {
445 enum gdb_osabi *osabi = (enum gdb_osabi *) obj;
446 const char *name;
447 unsigned int sectsize;
448 char *note;
449
450 name = bfd_section_name (sect);
451 sectsize = bfd_section_size (sect);
452
453 /* Limit the amount of data to read. */
454 if (sectsize > MAX_NOTESZ)
455 sectsize = MAX_NOTESZ;
456
457 /* We lazily read the section data here. Since we use
458 BFD_DECOMPRESS, we can't use bfd_get_section_contents on a
459 compressed section. But, since note sections are not compressed,
460 deferring the reading until we recognize the section avoids any
461 error. */
462 note = (char *) alloca (sectsize);
463
464 /* .note.ABI-tag notes, used by GNU/Linux and FreeBSD. */
465 if (strcmp (name, ".note.ABI-tag") == 0)
466 {
467 /* GNU. */
468 if (check_note (abfd, sect, note, &sectsize, "GNU", 16, NT_GNU_ABI_TAG))
469 {
470 unsigned int abi_tag = bfd_h_get_32 (abfd, note + 16);
471
472 switch (abi_tag)
473 {
474 case GNU_ABI_TAG_LINUX:
475 *osabi = GDB_OSABI_LINUX;
476 break;
477
478 case GNU_ABI_TAG_HURD:
479 *osabi = GDB_OSABI_HURD;
480 break;
481
482 case GNU_ABI_TAG_SOLARIS:
483 *osabi = GDB_OSABI_SOLARIS;
484 break;
485
486 case GNU_ABI_TAG_FREEBSD:
487 *osabi = GDB_OSABI_FREEBSD;
488 break;
489
490 case GNU_ABI_TAG_NETBSD:
491 *osabi = GDB_OSABI_NETBSD;
492 break;
493
494 default:
495 warning (_("GNU ABI tag value %u unrecognized."), abi_tag);
496 break;
497 }
498 return;
499 }
500
501 /* FreeBSD. */
502 if (check_note (abfd, sect, note, &sectsize, "FreeBSD", 4,
503 NT_FREEBSD_ABI_TAG))
504 {
505 /* There is no need to check the version yet. */
506 *osabi = GDB_OSABI_FREEBSD;
507 return;
508 }
509
510 return;
511 }
512
513 /* .note.netbsd.ident notes, used by NetBSD. */
514 if (strcmp (name, ".note.netbsd.ident") == 0
515 && check_note (abfd, sect, note, &sectsize, "NetBSD", 4, NT_NETBSD_IDENT))
516 {
517 /* There is no need to check the version yet. */
518 *osabi = GDB_OSABI_NETBSD;
519 return;
520 }
521
522 /* .note.openbsd.ident notes, used by OpenBSD. */
523 if (strcmp (name, ".note.openbsd.ident") == 0
524 && check_note (abfd, sect, note, &sectsize, "OpenBSD", 4,
525 NT_OPENBSD_IDENT))
526 {
527 /* There is no need to check the version yet. */
528 *osabi = GDB_OSABI_OPENBSD;
529 return;
530 }
531
532 /* .note.netbsdcore.procinfo notes, used by NetBSD. */
533 if (strcmp (name, ".note.netbsdcore.procinfo") == 0)
534 {
535 *osabi = GDB_OSABI_NETBSD;
536 return;
537 }
538 }
539
540 static enum gdb_osabi
541 generic_elf_osabi_sniffer (bfd *abfd)
542 {
543 unsigned int elfosabi;
544 enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
545
546 elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI];
547
548 switch (elfosabi)
549 {
550 case ELFOSABI_NONE:
551 case ELFOSABI_GNU:
552 case ELFOSABI_HPUX:
553 /* When the EI_OSABI field in the ELF header is ELFOSABI_NONE
554 (0), then the ELF structures in the file are conforming to
555 the base specification for that machine (there are no
556 OS-specific extensions). In order to determine the real OS
557 in use, we must look for OS-specific notes.
558
559 The same applies for ELFOSABI_GNU: this can mean GNU/Hurd,
560 GNU/Linux, and possibly more. */
561
562 /* And likewise ELFOSABI_HPUX. For some reason the default
563 value for the EI_OSABI field is ELFOSABI_HPUX for all PA-RISC
564 targets (with the exception of GNU/Linux). */
565 bfd_map_over_sections (abfd,
566 generic_elf_osabi_sniff_abi_tag_sections,
567 &osabi);
568 break;
569
570 case ELFOSABI_FREEBSD:
571 osabi = GDB_OSABI_FREEBSD;
572 break;
573
574 case ELFOSABI_NETBSD:
575 osabi = GDB_OSABI_NETBSD;
576 break;
577
578 case ELFOSABI_SOLARIS:
579 osabi = GDB_OSABI_SOLARIS;
580 break;
581
582 case ELFOSABI_OPENVMS:
583 osabi = GDB_OSABI_OPENVMS;
584 break;
585 }
586
587 if (osabi == GDB_OSABI_UNKNOWN)
588 {
589 /* The FreeBSD folks have been naughty; they stored the string
590 "FreeBSD" in the padding of the e_ident field of the ELF
591 header to "brand" their ELF binaries in FreeBSD 3.x. */
592 if (memcmp (&elf_elfheader (abfd)->e_ident[8],
593 "FreeBSD", sizeof ("FreeBSD")) == 0)
594 osabi = GDB_OSABI_FREEBSD;
595 }
596
597 return osabi;
598 }
599 \f
600 static void
601 set_osabi (const char *args, int from_tty, struct cmd_list_element *c)
602 {
603 struct gdbarch_info info;
604
605 if (strcmp (set_osabi_string, "auto") == 0)
606 user_osabi_state = osabi_auto;
607 else if (strcmp (set_osabi_string, "default") == 0)
608 {
609 user_selected_osabi = GDB_OSABI_DEFAULT;
610 user_osabi_state = osabi_user;
611 }
612 else
613 {
614 int i;
615
616 for (i = 1; i < GDB_OSABI_INVALID; i++)
617 {
618 enum gdb_osabi osabi = (enum gdb_osabi) i;
619
620 if (strcmp (set_osabi_string, gdbarch_osabi_name (osabi)) == 0)
621 {
622 user_selected_osabi = osabi;
623 user_osabi_state = osabi_user;
624 break;
625 }
626 }
627 if (i == GDB_OSABI_INVALID)
628 internal_error (__FILE__, __LINE__,
629 _("Invalid OS ABI \"%s\" passed to command handler."),
630 set_osabi_string);
631 }
632
633 /* NOTE: At some point (true multiple architectures) we'll need to be more
634 graceful here. */
635 gdbarch_info_init (&info);
636 if (! gdbarch_update_p (info))
637 internal_error (__FILE__, __LINE__, _("Updating OS ABI failed."));
638 }
639
640 static void
641 show_osabi (struct ui_file *file, int from_tty, struct cmd_list_element *c,
642 const char *value)
643 {
644 if (user_osabi_state == osabi_auto)
645 fprintf_filtered (file,
646 _("The current OS ABI is \"auto\" "
647 "(currently \"%s\").\n"),
648 gdbarch_osabi_name (gdbarch_osabi (get_current_arch ())));
649 else
650 fprintf_filtered (file, _("The current OS ABI is \"%s\".\n"),
651 gdbarch_osabi_name (user_selected_osabi));
652
653 if (GDB_OSABI_DEFAULT != GDB_OSABI_UNKNOWN)
654 fprintf_filtered (file, _("The default OS ABI is \"%s\".\n"),
655 gdbarch_osabi_name (GDB_OSABI_DEFAULT));
656 }
657
658 void
659 _initialize_gdb_osabi (void)
660 {
661 if (strcmp (gdb_osabi_names[GDB_OSABI_INVALID].pretty, "<invalid>") != 0)
662 internal_error
663 (__FILE__, __LINE__,
664 _("_initialize_gdb_osabi: gdb_osabi_names[] is inconsistent"));
665
666 /* Register a generic sniffer for ELF flavoured files. */
667 gdbarch_register_osabi_sniffer (bfd_arch_unknown,
668 bfd_target_elf_flavour,
669 generic_elf_osabi_sniffer);
670
671 /* Register the "set osabi" command. */
672 add_setshow_enum_cmd ("osabi", class_support, gdb_osabi_available_names,
673 &set_osabi_string,
674 _("Set OS ABI of target."),
675 _("Show OS ABI of target."),
676 NULL, set_osabi, show_osabi,
677 &setlist, &showlist);
678 user_osabi_state = osabi_auto;
679 }
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