1 /* Generate a core file for the inferior process.
3 Copyright (C) 2001-2012 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"
32 #include "gdb_assert.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 (char *filename
)
54 bfd
*obfd
= bfd_openw (filename
, default_gcore_target ());
58 error (_("Failed to open '%s' for output."), filename
);
59 gdb_bfd_stash_filename (obfd
);
60 bfd_set_format (obfd
, bfd_core
);
61 bfd_set_arch_mach (obfd
, default_gcore_arch (), default_gcore_mach ());
65 /* write_gcore_file -- helper for gcore_command (exported).
66 Compose and write the corefile data to the core file. */
70 write_gcore_file (bfd
*obfd
)
72 void *note_data
= NULL
;
74 asection
*note_sec
= NULL
;
76 /* An external target method must build the notes section. */
77 /* FIXME: uweigand/2011-10-06: All architectures that support core file
78 generation should be converted to gdbarch_make_corefile_notes; at that
79 point, the target vector method can be removed. */
80 if (!gdbarch_make_corefile_notes_p (target_gdbarch
))
81 note_data
= target_make_corefile_notes (obfd
, ¬e_size
);
83 note_data
= gdbarch_make_corefile_notes (target_gdbarch
, obfd
, ¬e_size
);
85 if (note_data
== NULL
|| note_size
== 0)
86 error (_("Target does not support core file generation."));
88 /* Create the note section. */
89 note_sec
= bfd_make_section_anyway_with_flags (obfd
, "note0",
94 error (_("Failed to create 'note' section for corefile: %s"),
95 bfd_errmsg (bfd_get_error ()));
97 bfd_set_section_vma (obfd
, note_sec
, 0);
98 bfd_set_section_alignment (obfd
, note_sec
, 0);
99 bfd_set_section_size (obfd
, note_sec
, note_size
);
101 /* Now create the memory/load sections. */
102 if (gcore_memory_sections (obfd
) == 0)
103 error (_("gcore: failed to get corefile memory sections from target."));
105 /* Write out the contents of the note section. */
106 if (!bfd_set_section_contents (obfd
, note_sec
, note_data
, 0, note_size
))
107 warning (_("writing note section (%s)"), bfd_errmsg (bfd_get_error ()));
111 do_bfd_delete_cleanup (void *arg
)
114 const char *filename
= obfd
->filename
;
120 /* gcore_command -- implements the 'gcore' command.
121 Generate a core file from the inferior process. */
124 gcore_command (char *args
, int from_tty
)
126 struct cleanup
*old_chain
;
127 char *corefilename
, corefilename_buffer
[40];
130 /* No use generating a corefile without a target process. */
131 if (!target_has_execution
)
138 /* Default corefile name is "core.PID". */
139 sprintf (corefilename_buffer
, "core.%d", PIDGET (inferior_ptid
));
140 corefilename
= corefilename_buffer
;
144 fprintf_filtered (gdb_stdout
,
145 "Opening corefile '%s' for output.\n", corefilename
);
147 /* Open the output file. */
148 obfd
= create_gcore_bfd (corefilename
);
150 /* Need a cleanup that will close and delete the file. */
151 old_chain
= make_cleanup (do_bfd_delete_cleanup
, obfd
);
153 /* Call worker function. */
154 write_gcore_file (obfd
);
157 fprintf_filtered (gdb_stdout
, "Saved corefile %s\n", corefilename
);
159 discard_cleanups (old_chain
);
160 gdb_bfd_unref (obfd
);
164 default_gcore_mach (void)
166 #if 1 /* See if this even matters... */
170 const struct bfd_arch_info
*bfdarch
= gdbarch_bfd_arch_info (target_gdbarch
);
173 return bfdarch
->mach
;
174 if (exec_bfd
== NULL
)
175 error (_("Can't find default bfd machine type (need execfile)."));
177 return bfd_get_mach (exec_bfd
);
181 static enum bfd_architecture
182 default_gcore_arch (void)
184 const struct bfd_arch_info
*bfdarch
= gdbarch_bfd_arch_info (target_gdbarch
);
187 return bfdarch
->arch
;
188 if (exec_bfd
== NULL
)
189 error (_("Can't find bfd architecture for corefile (need execfile)."));
191 return bfd_get_arch (exec_bfd
);
195 default_gcore_target (void)
197 /* The gdbarch may define a target to use for core files. */
198 if (gdbarch_gcore_bfd_target_p (target_gdbarch
))
199 return gdbarch_gcore_bfd_target (target_gdbarch
);
201 /* Otherwise, try to fall back to the exec_bfd target. This will probably
202 not work for non-ELF targets. */
203 if (exec_bfd
== NULL
)
206 return bfd_get_target (exec_bfd
);
209 /* Derive a reasonable stack segment by unwinding the target stack,
210 and store its limits in *BOTTOM and *TOP. Return non-zero if
214 derive_stack_segment (bfd_vma
*bottom
, bfd_vma
*top
)
216 struct frame_info
*fi
, *tmp_fi
;
221 /* Can't succeed without stack and registers. */
222 if (!target_has_stack
|| !target_has_registers
)
225 /* Can't succeed without current frame. */
226 fi
= get_current_frame ();
230 /* Save frame pointer of TOS frame. */
231 *top
= get_frame_base (fi
);
232 /* If current stack pointer is more "inner", use that instead. */
233 if (gdbarch_inner_than (get_frame_arch (fi
), get_frame_sp (fi
), *top
))
234 *top
= get_frame_sp (fi
);
236 /* Find prev-most frame. */
237 while ((tmp_fi
= get_prev_frame (fi
)) != NULL
)
240 /* Save frame pointer of prev-most frame. */
241 *bottom
= get_frame_base (fi
);
243 /* Now canonicalize their order, so that BOTTOM is a lower address
244 (as opposed to a lower stack frame). */
257 /* call_target_sbrk --
258 helper function for derive_heap_segment. */
261 call_target_sbrk (int sbrk_arg
)
263 struct objfile
*sbrk_objf
;
264 struct gdbarch
*gdbarch
;
266 struct value
*target_sbrk_arg
;
267 struct value
*sbrk_fn
, *ret
;
270 if (lookup_minimal_symbol ("sbrk", NULL
, NULL
) != NULL
)
272 sbrk_fn
= find_function_in_inferior ("sbrk", &sbrk_objf
);
276 else if (lookup_minimal_symbol ("_sbrk", NULL
, NULL
) != NULL
)
278 sbrk_fn
= find_function_in_inferior ("_sbrk", &sbrk_objf
);
285 gdbarch
= get_objfile_arch (sbrk_objf
);
286 target_sbrk_arg
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
288 gdb_assert (target_sbrk_arg
);
289 ret
= call_function_by_hand (sbrk_fn
, 1, &target_sbrk_arg
);
293 tmp
= value_as_long (ret
);
294 if ((LONGEST
) tmp
<= 0 || (LONGEST
) tmp
== 0xffffffff)
301 /* Derive a reasonable heap segment for ABFD by looking at sbrk and
302 the static data sections. Store its limits in *BOTTOM and *TOP.
303 Return non-zero if successful. */
306 derive_heap_segment (bfd
*abfd
, bfd_vma
*bottom
, bfd_vma
*top
)
308 bfd_vma top_of_data_memory
= 0;
309 bfd_vma top_of_heap
= 0;
310 bfd_size_type sec_size
;
317 /* This function depends on being able to call a function in the
319 if (!target_has_execution
)
322 /* The following code assumes that the link map is arranged as
323 follows (low to high addresses):
325 ---------------------------------
327 ---------------------------------
328 | data sections (including bss) |
329 ---------------------------------
331 --------------------------------- */
333 for (sec
= abfd
->sections
; sec
; sec
= sec
->next
)
335 if (bfd_get_section_flags (abfd
, sec
) & SEC_DATA
336 || strcmp (".bss", bfd_section_name (abfd
, sec
)) == 0)
338 sec_vaddr
= bfd_get_section_vma (abfd
, sec
);
339 sec_size
= bfd_get_section_size (sec
);
340 if (sec_vaddr
+ sec_size
> top_of_data_memory
)
341 top_of_data_memory
= sec_vaddr
+ sec_size
;
345 top_of_heap
= call_target_sbrk (0);
346 if (top_of_heap
== (bfd_vma
) 0)
349 /* Return results. */
350 if (top_of_heap
> top_of_data_memory
)
352 *bottom
= top_of_data_memory
;
357 /* No additional heap space needs to be saved. */
362 make_output_phdrs (bfd
*obfd
, asection
*osec
, void *ignored
)
367 /* FIXME: these constants may only be applicable for ELF. */
368 if (strncmp (bfd_section_name (obfd
, osec
), "load", 4) == 0)
370 else if (strncmp (bfd_section_name (obfd
, osec
), "note", 4) == 0)
375 p_flags
|= PF_R
; /* Segment is readable. */
376 if (!(bfd_get_section_flags (obfd
, osec
) & SEC_READONLY
))
377 p_flags
|= PF_W
; /* Segment is writable. */
378 if (bfd_get_section_flags (obfd
, osec
) & SEC_CODE
)
379 p_flags
|= PF_X
; /* Segment is executable. */
381 bfd_record_phdr (obfd
, p_type
, 1, p_flags
, 0, 0, 0, 0, 1, &osec
);
385 gcore_create_callback (CORE_ADDR vaddr
, unsigned long size
,
386 int read
, int write
, int exec
, void *data
)
390 flagword flags
= SEC_ALLOC
| SEC_HAS_CONTENTS
| SEC_LOAD
;
392 /* If the memory segment has no permissions set, ignore it, otherwise
393 when we later try to access it for read/write, we'll get an error
394 or jam the kernel. */
395 if (read
== 0 && write
== 0 && exec
== 0)
399 fprintf_filtered (gdb_stdout
, "Ignore segment, %s bytes at %s\n",
400 plongest (size
), paddress (target_gdbarch
, vaddr
));
406 if (write
== 0 && !solib_keep_data_in_core (vaddr
, size
))
408 /* See if this region of memory lies inside a known file on disk.
409 If so, we can avoid copying its contents by clearing SEC_LOAD. */
410 struct objfile
*objfile
;
411 struct obj_section
*objsec
;
413 ALL_OBJSECTIONS (objfile
, objsec
)
415 bfd
*abfd
= objfile
->obfd
;
416 asection
*asec
= objsec
->the_bfd_section
;
417 bfd_vma align
= (bfd_vma
) 1 << bfd_get_section_alignment (abfd
,
419 bfd_vma start
= obj_section_addr (objsec
) & -align
;
420 bfd_vma end
= (obj_section_endaddr (objsec
) + align
- 1) & -align
;
422 /* Match if either the entire memory region lies inside the
423 section (i.e. a mapping covering some pages of a large
424 segment) or the entire section lies inside the memory region
425 (i.e. a mapping covering multiple small sections).
427 This BFD was synthesized from reading target memory,
428 we don't want to omit that. */
429 if (((vaddr
>= start
&& vaddr
+ size
<= end
)
430 || (start
>= vaddr
&& end
<= vaddr
+ size
))
431 && !(bfd_get_file_flags (abfd
) & BFD_IN_MEMORY
))
433 flags
&= ~(SEC_LOAD
| SEC_HAS_CONTENTS
);
434 goto keep
; /* Break out of two nested for loops. */
439 flags
|= SEC_READONLY
;
447 osec
= bfd_make_section_anyway_with_flags (obfd
, "load", flags
);
450 warning (_("Couldn't make gcore segment: %s"),
451 bfd_errmsg (bfd_get_error ()));
457 fprintf_filtered (gdb_stdout
, "Save segment, %s bytes at %s\n",
458 plongest (size
), paddress (target_gdbarch
, vaddr
));
461 bfd_set_section_size (obfd
, osec
, size
);
462 bfd_set_section_vma (obfd
, osec
, vaddr
);
463 bfd_section_lma (obfd
, osec
) = 0; /* ??? bfd_set_section_lma? */
468 objfile_find_memory_regions (find_memory_region_ftype func
, void *obfd
)
470 /* Use objfile data to create memory sections. */
471 struct objfile
*objfile
;
472 struct obj_section
*objsec
;
473 bfd_vma temp_bottom
, temp_top
;
475 /* Call callback function for each objfile section. */
476 ALL_OBJSECTIONS (objfile
, objsec
)
478 bfd
*ibfd
= objfile
->obfd
;
479 asection
*isec
= objsec
->the_bfd_section
;
480 flagword flags
= bfd_get_section_flags (ibfd
, isec
);
482 if ((flags
& SEC_ALLOC
) || (flags
& SEC_LOAD
))
484 int size
= bfd_section_size (ibfd
, isec
);
487 ret
= (*func
) (obj_section_addr (objsec
), size
,
488 1, /* All sections will be readable. */
489 (flags
& SEC_READONLY
) == 0, /* Writable. */
490 (flags
& SEC_CODE
) != 0, /* Executable. */
497 /* Make a stack segment. */
498 if (derive_stack_segment (&temp_bottom
, &temp_top
))
499 (*func
) (temp_bottom
, temp_top
- temp_bottom
,
500 1, /* Stack section will be readable. */
501 1, /* Stack section will be writable. */
502 0, /* Stack section will not be executable. */
505 /* Make a heap segment. */
506 if (derive_heap_segment (exec_bfd
, &temp_bottom
, &temp_top
))
507 (*func
) (temp_bottom
, temp_top
- temp_bottom
,
508 1, /* Heap section will be readable. */
509 1, /* Heap section will be writable. */
510 0, /* Heap section will not be executable. */
517 gcore_copy_callback (bfd
*obfd
, asection
*osec
, void *ignored
)
519 bfd_size_type size
, total_size
= bfd_section_size (obfd
, osec
);
521 struct cleanup
*old_chain
= NULL
;
524 /* Read-only sections are marked; we don't have to copy their contents. */
525 if ((bfd_get_section_flags (obfd
, osec
) & SEC_LOAD
) == 0)
528 /* Only interested in "load" sections. */
529 if (strncmp ("load", bfd_section_name (obfd
, osec
), 4) != 0)
532 size
= min (total_size
, MAX_COPY_BYTES
);
533 memhunk
= xmalloc (size
);
534 old_chain
= make_cleanup (xfree
, memhunk
);
536 while (total_size
> 0)
538 if (size
> total_size
)
541 if (target_read_memory (bfd_section_vma (obfd
, osec
) + offset
,
544 warning (_("Memory read failed for corefile "
545 "section, %s bytes at %s."),
547 paddress (target_gdbarch
, bfd_section_vma (obfd
, osec
)));
550 if (!bfd_set_section_contents (obfd
, osec
, memhunk
, offset
, size
))
552 warning (_("Failed to write corefile contents (%s)."),
553 bfd_errmsg (bfd_get_error ()));
561 do_cleanups (old_chain
); /* Frees MEMHUNK. */
565 gcore_memory_sections (bfd
*obfd
)
567 /* Try gdbarch method first, then fall back to target method. */
568 if (!gdbarch_find_memory_regions_p (target_gdbarch
)
569 || gdbarch_find_memory_regions (target_gdbarch
,
570 gcore_create_callback
, obfd
) != 0)
572 if (target_find_memory_regions (gcore_create_callback
, obfd
) != 0)
573 return 0; /* FIXME: error return/msg? */
576 /* Record phdrs for section-to-segment mapping. */
577 bfd_map_over_sections (obfd
, make_output_phdrs
, NULL
);
579 /* Copy memory region contents. */
580 bfd_map_over_sections (obfd
, gcore_copy_callback
, NULL
);
585 /* Provide a prototype to silence -Wmissing-prototypes. */
586 extern initialize_file_ftype _initialize_gcore
;
589 _initialize_gcore (void)
591 add_com ("generate-core-file", class_files
, gcore_command
, _("\
592 Save a core file with the current state of the debugged process.\n\
593 Argument is optional filename. Default filename is 'core.<process_id>'."));
595 add_com_alias ("gcore", "generate-core-file", class_files
, 1);
596 exec_set_find_memory_regions (objfile_find_memory_regions
);