1 /* Generate a core file for the inferior process.
3 Copyright (C) 2001-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
28 #include "arch-utils.h"
29 #include "completer.h"
31 #include "cli/cli-decode.h"
36 #include "readline/tilde.h"
38 /* The largest amount of memory to read from the target at once. We
39 must throttle it to limit the amount of memory used by GDB during
40 generate-core-file for programs with large resident data. */
41 #define MAX_COPY_BYTES (1024 * 1024)
43 static const char *default_gcore_target (void);
44 static enum bfd_architecture
default_gcore_arch (void);
45 static unsigned long default_gcore_mach (void);
46 static int gcore_memory_sections (bfd
*);
48 /* create_gcore_bfd -- helper for gcore_command (exported).
49 Open a new bfd core file for output, and return the handle. */
52 create_gcore_bfd (const char *filename
)
54 bfd
*obfd
= gdb_bfd_openw (filename
, default_gcore_target ());
57 error (_("Failed to open '%s' for output."), filename
);
58 bfd_set_format (obfd
, bfd_core
);
59 bfd_set_arch_mach (obfd
, default_gcore_arch (), default_gcore_mach ());
63 /* write_gcore_file_1 -- do the actual work of write_gcore_file. */
66 write_gcore_file_1 (bfd
*obfd
)
68 struct cleanup
*cleanup
;
69 void *note_data
= NULL
;
71 asection
*note_sec
= NULL
;
73 /* An external target method must build the notes section. */
74 /* FIXME: uweigand/2011-10-06: All architectures that support core file
75 generation should be converted to gdbarch_make_corefile_notes; at that
76 point, the target vector method can be removed. */
77 if (!gdbarch_make_corefile_notes_p (target_gdbarch ()))
78 note_data
= target_make_corefile_notes (obfd
, ¬e_size
);
80 note_data
= gdbarch_make_corefile_notes (target_gdbarch (), obfd
, ¬e_size
);
82 cleanup
= make_cleanup (xfree
, note_data
);
84 if (note_data
== NULL
|| note_size
== 0)
85 error (_("Target does not support core file generation."));
87 /* Create the note section. */
88 note_sec
= bfd_make_section_anyway_with_flags (obfd
, "note0",
93 error (_("Failed to create 'note' section for corefile: %s"),
94 bfd_errmsg (bfd_get_error ()));
96 bfd_set_section_vma (obfd
, note_sec
, 0);
97 bfd_set_section_alignment (obfd
, note_sec
, 0);
98 bfd_set_section_size (obfd
, note_sec
, note_size
);
100 /* Now create the memory/load sections. */
101 if (gcore_memory_sections (obfd
) == 0)
102 error (_("gcore: failed to get corefile memory sections from target."));
104 /* Write out the contents of the note section. */
105 if (!bfd_set_section_contents (obfd
, note_sec
, note_data
, 0, note_size
))
106 warning (_("writing note section (%s)"), bfd_errmsg (bfd_get_error ()));
108 do_cleanups (cleanup
);
111 /* write_gcore_file -- helper for gcore_command (exported).
112 Compose and write the corefile data to the core file. */
115 write_gcore_file (bfd
*obfd
)
117 struct gdb_exception except
= exception_none
;
119 target_prepare_to_generate_core ();
123 write_gcore_file_1 (obfd
);
125 CATCH (e
, RETURN_MASK_ALL
)
131 target_done_generating_core ();
133 if (except
.reason
< 0)
134 throw_exception (except
);
138 do_bfd_delete_cleanup (void *arg
)
140 bfd
*obfd
= (bfd
*) arg
;
141 const char *filename
= obfd
->filename
;
143 gdb_bfd_unref ((bfd
*) arg
);
147 /* gcore_command -- implements the 'gcore' command.
148 Generate a core file from the inferior process. */
151 gcore_command (char *args
, int from_tty
)
153 struct cleanup
*filename_chain
;
154 struct cleanup
*bfd_chain
;
158 /* No use generating a corefile without a target process. */
159 if (!target_has_execution
)
163 corefilename
= tilde_expand (args
);
166 /* Default corefile name is "core.PID". */
167 corefilename
= xstrprintf ("core.%d", ptid_get_pid (inferior_ptid
));
169 filename_chain
= make_cleanup (xfree
, corefilename
);
172 fprintf_filtered (gdb_stdout
,
173 "Opening corefile '%s' for output.\n", corefilename
);
175 /* Open the output file. */
176 obfd
= create_gcore_bfd (corefilename
);
178 /* Need a cleanup that will close and delete the file. */
179 bfd_chain
= make_cleanup (do_bfd_delete_cleanup
, obfd
);
181 /* Call worker function. */
182 write_gcore_file (obfd
);
185 discard_cleanups (bfd_chain
);
186 gdb_bfd_unref (obfd
);
188 fprintf_filtered (gdb_stdout
, "Saved corefile %s\n", corefilename
);
189 do_cleanups (filename_chain
);
193 default_gcore_mach (void)
195 #if 1 /* See if this even matters... */
199 const struct bfd_arch_info
*bfdarch
= gdbarch_bfd_arch_info (target_gdbarch ());
202 return bfdarch
->mach
;
203 if (exec_bfd
== NULL
)
204 error (_("Can't find default bfd machine type (need execfile)."));
206 return bfd_get_mach (exec_bfd
);
210 static enum bfd_architecture
211 default_gcore_arch (void)
213 const struct bfd_arch_info
*bfdarch
= gdbarch_bfd_arch_info (target_gdbarch ());
216 return bfdarch
->arch
;
217 if (exec_bfd
== NULL
)
218 error (_("Can't find bfd architecture for corefile (need execfile)."));
220 return bfd_get_arch (exec_bfd
);
224 default_gcore_target (void)
226 /* The gdbarch may define a target to use for core files. */
227 if (gdbarch_gcore_bfd_target_p (target_gdbarch ()))
228 return gdbarch_gcore_bfd_target (target_gdbarch ());
230 /* Otherwise, try to fall back to the exec_bfd target. This will probably
231 not work for non-ELF targets. */
232 if (exec_bfd
== NULL
)
235 return bfd_get_target (exec_bfd
);
238 /* Derive a reasonable stack segment by unwinding the target stack,
239 and store its limits in *BOTTOM and *TOP. Return non-zero if
243 derive_stack_segment (bfd_vma
*bottom
, bfd_vma
*top
)
245 struct frame_info
*fi
, *tmp_fi
;
250 /* Can't succeed without stack and registers. */
251 if (!target_has_stack
|| !target_has_registers
)
254 /* Can't succeed without current frame. */
255 fi
= get_current_frame ();
259 /* Save frame pointer of TOS frame. */
260 *top
= get_frame_base (fi
);
261 /* If current stack pointer is more "inner", use that instead. */
262 if (gdbarch_inner_than (get_frame_arch (fi
), get_frame_sp (fi
), *top
))
263 *top
= get_frame_sp (fi
);
265 /* Find prev-most frame. */
266 while ((tmp_fi
= get_prev_frame (fi
)) != NULL
)
269 /* Save frame pointer of prev-most frame. */
270 *bottom
= get_frame_base (fi
);
272 /* Now canonicalize their order, so that BOTTOM is a lower address
273 (as opposed to a lower stack frame). */
286 /* call_target_sbrk --
287 helper function for derive_heap_segment. */
290 call_target_sbrk (int sbrk_arg
)
292 struct objfile
*sbrk_objf
;
293 struct gdbarch
*gdbarch
;
295 struct value
*target_sbrk_arg
;
296 struct value
*sbrk_fn
, *ret
;
299 if (lookup_minimal_symbol ("sbrk", NULL
, NULL
).minsym
!= NULL
)
301 sbrk_fn
= find_function_in_inferior ("sbrk", &sbrk_objf
);
305 else if (lookup_minimal_symbol ("_sbrk", NULL
, NULL
).minsym
!= NULL
)
307 sbrk_fn
= find_function_in_inferior ("_sbrk", &sbrk_objf
);
314 gdbarch
= get_objfile_arch (sbrk_objf
);
315 target_sbrk_arg
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
317 gdb_assert (target_sbrk_arg
);
318 ret
= call_function_by_hand (sbrk_fn
, 1, &target_sbrk_arg
);
322 tmp
= value_as_long (ret
);
323 if ((LONGEST
) tmp
<= 0 || (LONGEST
) tmp
== 0xffffffff)
330 /* Derive a reasonable heap segment for ABFD by looking at sbrk and
331 the static data sections. Store its limits in *BOTTOM and *TOP.
332 Return non-zero if successful. */
335 derive_heap_segment (bfd
*abfd
, bfd_vma
*bottom
, bfd_vma
*top
)
337 bfd_vma top_of_data_memory
= 0;
338 bfd_vma top_of_heap
= 0;
339 bfd_size_type sec_size
;
346 /* This function depends on being able to call a function in the
348 if (!target_has_execution
)
351 /* The following code assumes that the link map is arranged as
352 follows (low to high addresses):
354 ---------------------------------
356 ---------------------------------
357 | data sections (including bss) |
358 ---------------------------------
360 --------------------------------- */
362 for (sec
= abfd
->sections
; sec
; sec
= sec
->next
)
364 if (bfd_get_section_flags (abfd
, sec
) & SEC_DATA
365 || strcmp (".bss", bfd_section_name (abfd
, sec
)) == 0)
367 sec_vaddr
= bfd_get_section_vma (abfd
, sec
);
368 sec_size
= bfd_get_section_size (sec
);
369 if (sec_vaddr
+ sec_size
> top_of_data_memory
)
370 top_of_data_memory
= sec_vaddr
+ sec_size
;
374 top_of_heap
= call_target_sbrk (0);
375 if (top_of_heap
== (bfd_vma
) 0)
378 /* Return results. */
379 if (top_of_heap
> top_of_data_memory
)
381 *bottom
= top_of_data_memory
;
386 /* No additional heap space needs to be saved. */
391 make_output_phdrs (bfd
*obfd
, asection
*osec
, void *ignored
)
396 /* FIXME: these constants may only be applicable for ELF. */
397 if (startswith (bfd_section_name (obfd
, osec
), "load"))
399 else if (startswith (bfd_section_name (obfd
, osec
), "note"))
404 p_flags
|= PF_R
; /* Segment is readable. */
405 if (!(bfd_get_section_flags (obfd
, osec
) & SEC_READONLY
))
406 p_flags
|= PF_W
; /* Segment is writable. */
407 if (bfd_get_section_flags (obfd
, osec
) & SEC_CODE
)
408 p_flags
|= PF_X
; /* Segment is executable. */
410 bfd_record_phdr (obfd
, p_type
, 1, p_flags
, 0, 0, 0, 0, 1, &osec
);
413 /* find_memory_region_ftype implementation. DATA is 'bfd *' for the core file
417 gcore_create_callback (CORE_ADDR vaddr
, unsigned long size
, int read
,
418 int write
, int exec
, int modified
, void *data
)
420 bfd
*obfd
= (bfd
*) data
;
422 flagword flags
= SEC_ALLOC
| SEC_HAS_CONTENTS
| SEC_LOAD
;
424 /* If the memory segment has no permissions set, ignore it, otherwise
425 when we later try to access it for read/write, we'll get an error
426 or jam the kernel. */
427 if (read
== 0 && write
== 0 && exec
== 0 && modified
== 0)
431 fprintf_filtered (gdb_stdout
, "Ignore segment, %s bytes at %s\n",
432 plongest (size
), paddress (target_gdbarch (), vaddr
));
438 if (write
== 0 && modified
== 0 && !solib_keep_data_in_core (vaddr
, size
))
440 /* See if this region of memory lies inside a known file on disk.
441 If so, we can avoid copying its contents by clearing SEC_LOAD. */
442 struct objfile
*objfile
;
443 struct obj_section
*objsec
;
445 ALL_OBJSECTIONS (objfile
, objsec
)
447 bfd
*abfd
= objfile
->obfd
;
448 asection
*asec
= objsec
->the_bfd_section
;
449 bfd_vma align
= (bfd_vma
) 1 << bfd_get_section_alignment (abfd
,
451 bfd_vma start
= obj_section_addr (objsec
) & -align
;
452 bfd_vma end
= (obj_section_endaddr (objsec
) + align
- 1) & -align
;
454 /* Match if either the entire memory region lies inside the
455 section (i.e. a mapping covering some pages of a large
456 segment) or the entire section lies inside the memory region
457 (i.e. a mapping covering multiple small sections).
459 This BFD was synthesized from reading target memory,
460 we don't want to omit that. */
461 if (objfile
->separate_debug_objfile_backlink
== NULL
462 && ((vaddr
>= start
&& vaddr
+ size
<= end
)
463 || (start
>= vaddr
&& end
<= vaddr
+ size
))
464 && !(bfd_get_file_flags (abfd
) & BFD_IN_MEMORY
))
466 flags
&= ~(SEC_LOAD
| SEC_HAS_CONTENTS
);
467 goto keep
; /* Break out of two nested for loops. */
475 flags
|= SEC_READONLY
;
482 osec
= bfd_make_section_anyway_with_flags (obfd
, "load", flags
);
485 warning (_("Couldn't make gcore segment: %s"),
486 bfd_errmsg (bfd_get_error ()));
492 fprintf_filtered (gdb_stdout
, "Save segment, %s bytes at %s\n",
493 plongest (size
), paddress (target_gdbarch (), vaddr
));
496 bfd_set_section_size (obfd
, osec
, size
);
497 bfd_set_section_vma (obfd
, osec
, vaddr
);
498 bfd_section_lma (obfd
, osec
) = 0; /* ??? bfd_set_section_lma? */
503 objfile_find_memory_regions (struct target_ops
*self
,
504 find_memory_region_ftype func
, void *obfd
)
506 /* Use objfile data to create memory sections. */
507 struct objfile
*objfile
;
508 struct obj_section
*objsec
;
509 bfd_vma temp_bottom
, temp_top
;
511 /* Call callback function for each objfile section. */
512 ALL_OBJSECTIONS (objfile
, objsec
)
514 bfd
*ibfd
= objfile
->obfd
;
515 asection
*isec
= objsec
->the_bfd_section
;
516 flagword flags
= bfd_get_section_flags (ibfd
, isec
);
518 /* Separate debug info files are irrelevant for gcore. */
519 if (objfile
->separate_debug_objfile_backlink
!= NULL
)
522 if ((flags
& SEC_ALLOC
) || (flags
& SEC_LOAD
))
524 int size
= bfd_section_size (ibfd
, isec
);
527 ret
= (*func
) (obj_section_addr (objsec
), size
,
528 1, /* All sections will be readable. */
529 (flags
& SEC_READONLY
) == 0, /* Writable. */
530 (flags
& SEC_CODE
) != 0, /* Executable. */
531 1, /* MODIFIED is unknown, pass it as true. */
538 /* Make a stack segment. */
539 if (derive_stack_segment (&temp_bottom
, &temp_top
))
540 (*func
) (temp_bottom
, temp_top
- temp_bottom
,
541 1, /* Stack section will be readable. */
542 1, /* Stack section will be writable. */
543 0, /* Stack section will not be executable. */
544 1, /* Stack section will be modified. */
547 /* Make a heap segment. */
548 if (derive_heap_segment (exec_bfd
, &temp_bottom
, &temp_top
))
549 (*func
) (temp_bottom
, temp_top
- temp_bottom
,
550 1, /* Heap section will be readable. */
551 1, /* Heap section will be writable. */
552 0, /* Heap section will not be executable. */
553 1, /* Heap section will be modified. */
560 gcore_copy_callback (bfd
*obfd
, asection
*osec
, void *ignored
)
562 bfd_size_type size
, total_size
= bfd_section_size (obfd
, osec
);
564 struct cleanup
*old_chain
= NULL
;
567 /* Read-only sections are marked; we don't have to copy their contents. */
568 if ((bfd_get_section_flags (obfd
, osec
) & SEC_LOAD
) == 0)
571 /* Only interested in "load" sections. */
572 if (!startswith (bfd_section_name (obfd
, osec
), "load"))
575 size
= min (total_size
, MAX_COPY_BYTES
);
576 memhunk
= (gdb_byte
*) xmalloc (size
);
577 old_chain
= make_cleanup (xfree
, memhunk
);
579 while (total_size
> 0)
581 if (size
> total_size
)
584 if (target_read_memory (bfd_section_vma (obfd
, osec
) + offset
,
587 warning (_("Memory read failed for corefile "
588 "section, %s bytes at %s."),
590 paddress (target_gdbarch (), bfd_section_vma (obfd
, osec
)));
593 if (!bfd_set_section_contents (obfd
, osec
, memhunk
, offset
, size
))
595 warning (_("Failed to write corefile contents (%s)."),
596 bfd_errmsg (bfd_get_error ()));
604 do_cleanups (old_chain
); /* Frees MEMHUNK. */
608 gcore_memory_sections (bfd
*obfd
)
610 /* Try gdbarch method first, then fall back to target method. */
611 if (!gdbarch_find_memory_regions_p (target_gdbarch ())
612 || gdbarch_find_memory_regions (target_gdbarch (),
613 gcore_create_callback
, obfd
) != 0)
615 if (target_find_memory_regions (gcore_create_callback
, obfd
) != 0)
616 return 0; /* FIXME: error return/msg? */
619 /* Record phdrs for section-to-segment mapping. */
620 bfd_map_over_sections (obfd
, make_output_phdrs
, NULL
);
622 /* Copy memory region contents. */
623 bfd_map_over_sections (obfd
, gcore_copy_callback
, NULL
);
628 /* Provide a prototype to silence -Wmissing-prototypes. */
629 extern initialize_file_ftype _initialize_gcore
;
632 _initialize_gcore (void)
634 add_com ("generate-core-file", class_files
, gcore_command
, _("\
635 Save a core file with the current state of the debugged process.\n\
636 Argument is optional filename. Default filename is 'core.<process_id>'."));
638 add_com_alias ("gcore", "generate-core-file", class_files
, 1);