1 /* Generate a core file for the inferior process.
3 Copyright (C) 2001-2013 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"
37 #include "readline/tilde.h"
39 /* The largest amount of memory to read from the target at once. We
40 must throttle it to limit the amount of memory used by GDB during
41 generate-core-file for programs with large resident data. */
42 #define MAX_COPY_BYTES (1024 * 1024)
44 static const char *default_gcore_target (void);
45 static enum bfd_architecture default_gcore_arch (void);
46 static unsigned long default_gcore_mach (void);
47 static int gcore_memory_sections (bfd *);
49 /* create_gcore_bfd -- helper for gcore_command (exported).
50 Open a new bfd core file for output, and return the handle. */
53 create_gcore_bfd (const char *filename)
58 fullname = tilde_expand (filename);
59 obfd = gdb_bfd_openw (fullname, default_gcore_target ());
63 error (_("Failed to open '%s' for output."), filename);
64 bfd_set_format (obfd, bfd_core);
65 bfd_set_arch_mach (obfd, default_gcore_arch (), default_gcore_mach ());
69 /* write_gcore_file -- helper for gcore_command (exported).
70 Compose and write the corefile data to the core file. */
74 write_gcore_file (bfd *obfd)
76 void *note_data = NULL;
78 asection *note_sec = NULL;
80 /* An external target method must build the notes section. */
81 /* FIXME: uweigand/2011-10-06: All architectures that support core file
82 generation should be converted to gdbarch_make_corefile_notes; at that
83 point, the target vector method can be removed. */
84 if (!gdbarch_make_corefile_notes_p (target_gdbarch ()))
85 note_data = target_make_corefile_notes (obfd, ¬e_size);
87 note_data = gdbarch_make_corefile_notes (target_gdbarch (), obfd, ¬e_size);
89 if (note_data == NULL || note_size == 0)
90 error (_("Target does not support core file generation."));
92 /* Create the note section. */
93 note_sec = bfd_make_section_anyway_with_flags (obfd, "note0",
98 error (_("Failed to create 'note' section for corefile: %s"),
99 bfd_errmsg (bfd_get_error ()));
101 bfd_set_section_vma (obfd, note_sec, 0);
102 bfd_set_section_alignment (obfd, note_sec, 0);
103 bfd_set_section_size (obfd, note_sec, note_size);
105 /* Now create the memory/load sections. */
106 if (gcore_memory_sections (obfd) == 0)
107 error (_("gcore: failed to get corefile memory sections from target."));
109 /* Write out the contents of the note section. */
110 if (!bfd_set_section_contents (obfd, note_sec, note_data, 0, note_size))
111 warning (_("writing note section (%s)"), bfd_errmsg (bfd_get_error ()));
115 do_bfd_delete_cleanup (void *arg)
118 const char *filename = obfd->filename;
124 /* gcore_command -- implements the 'gcore' command.
125 Generate a core file from the inferior process. */
128 gcore_command (char *args, int from_tty)
130 struct cleanup *old_chain;
131 char *corefilename, corefilename_buffer[40];
134 /* No use generating a corefile without a target process. */
135 if (!target_has_execution)
142 /* Default corefile name is "core.PID". */
143 xsnprintf (corefilename_buffer, sizeof (corefilename_buffer),
144 "core.%d", PIDGET (inferior_ptid));
145 corefilename = corefilename_buffer;
149 fprintf_filtered (gdb_stdout,
150 "Opening corefile '%s' for output.\n", corefilename);
152 /* Open the output file. */
153 obfd = create_gcore_bfd (corefilename);
155 /* Need a cleanup that will close and delete the file. */
156 old_chain = make_cleanup (do_bfd_delete_cleanup, obfd);
158 /* Call worker function. */
159 write_gcore_file (obfd);
162 fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename);
164 discard_cleanups (old_chain);
165 gdb_bfd_unref (obfd);
169 default_gcore_mach (void)
171 #if 1 /* See if this even matters... */
175 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
178 return bfdarch->mach;
179 if (exec_bfd == NULL)
180 error (_("Can't find default bfd machine type (need execfile)."));
182 return bfd_get_mach (exec_bfd);
186 static enum bfd_architecture
187 default_gcore_arch (void)
189 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
192 return bfdarch->arch;
193 if (exec_bfd == NULL)
194 error (_("Can't find bfd architecture for corefile (need execfile)."));
196 return bfd_get_arch (exec_bfd);
200 default_gcore_target (void)
202 /* The gdbarch may define a target to use for core files. */
203 if (gdbarch_gcore_bfd_target_p (target_gdbarch ()))
204 return gdbarch_gcore_bfd_target (target_gdbarch ());
206 /* Otherwise, try to fall back to the exec_bfd target. This will probably
207 not work for non-ELF targets. */
208 if (exec_bfd == NULL)
211 return bfd_get_target (exec_bfd);
214 /* Derive a reasonable stack segment by unwinding the target stack,
215 and store its limits in *BOTTOM and *TOP. Return non-zero if
219 derive_stack_segment (bfd_vma *bottom, bfd_vma *top)
221 struct frame_info *fi, *tmp_fi;
226 /* Can't succeed without stack and registers. */
227 if (!target_has_stack || !target_has_registers)
230 /* Can't succeed without current frame. */
231 fi = get_current_frame ();
235 /* Save frame pointer of TOS frame. */
236 *top = get_frame_base (fi);
237 /* If current stack pointer is more "inner", use that instead. */
238 if (gdbarch_inner_than (get_frame_arch (fi), get_frame_sp (fi), *top))
239 *top = get_frame_sp (fi);
241 /* Find prev-most frame. */
242 while ((tmp_fi = get_prev_frame (fi)) != NULL)
245 /* Save frame pointer of prev-most frame. */
246 *bottom = get_frame_base (fi);
248 /* Now canonicalize their order, so that BOTTOM is a lower address
249 (as opposed to a lower stack frame). */
262 /* call_target_sbrk --
263 helper function for derive_heap_segment. */
266 call_target_sbrk (int sbrk_arg)
268 struct objfile *sbrk_objf;
269 struct gdbarch *gdbarch;
271 struct value *target_sbrk_arg;
272 struct value *sbrk_fn, *ret;
275 if (lookup_minimal_symbol ("sbrk", NULL, NULL) != NULL)
277 sbrk_fn = find_function_in_inferior ("sbrk", &sbrk_objf);
281 else if (lookup_minimal_symbol ("_sbrk", NULL, NULL) != NULL)
283 sbrk_fn = find_function_in_inferior ("_sbrk", &sbrk_objf);
290 gdbarch = get_objfile_arch (sbrk_objf);
291 target_sbrk_arg = value_from_longest (builtin_type (gdbarch)->builtin_int,
293 gdb_assert (target_sbrk_arg);
294 ret = call_function_by_hand (sbrk_fn, 1, &target_sbrk_arg);
298 tmp = value_as_long (ret);
299 if ((LONGEST) tmp <= 0 || (LONGEST) tmp == 0xffffffff)
306 /* Derive a reasonable heap segment for ABFD by looking at sbrk and
307 the static data sections. Store its limits in *BOTTOM and *TOP.
308 Return non-zero if successful. */
311 derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top)
313 bfd_vma top_of_data_memory = 0;
314 bfd_vma top_of_heap = 0;
315 bfd_size_type sec_size;
322 /* This function depends on being able to call a function in the
324 if (!target_has_execution)
327 /* The following code assumes that the link map is arranged as
328 follows (low to high addresses):
330 ---------------------------------
332 ---------------------------------
333 | data sections (including bss) |
334 ---------------------------------
336 --------------------------------- */
338 for (sec = abfd->sections; sec; sec = sec->next)
340 if (bfd_get_section_flags (abfd, sec) & SEC_DATA
341 || strcmp (".bss", bfd_section_name (abfd, sec)) == 0)
343 sec_vaddr = bfd_get_section_vma (abfd, sec);
344 sec_size = bfd_get_section_size (sec);
345 if (sec_vaddr + sec_size > top_of_data_memory)
346 top_of_data_memory = sec_vaddr + sec_size;
350 top_of_heap = call_target_sbrk (0);
351 if (top_of_heap == (bfd_vma) 0)
354 /* Return results. */
355 if (top_of_heap > top_of_data_memory)
357 *bottom = top_of_data_memory;
362 /* No additional heap space needs to be saved. */
367 make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
372 /* FIXME: these constants may only be applicable for ELF. */
373 if (strncmp (bfd_section_name (obfd, osec), "load", 4) == 0)
375 else if (strncmp (bfd_section_name (obfd, osec), "note", 4) == 0)
380 p_flags |= PF_R; /* Segment is readable. */
381 if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY))
382 p_flags |= PF_W; /* Segment is writable. */
383 if (bfd_get_section_flags (obfd, osec) & SEC_CODE)
384 p_flags |= PF_X; /* Segment is executable. */
386 bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec);
389 /* find_memory_region_ftype implementation. DATA is 'bfd *' for the core file
393 gcore_create_callback (CORE_ADDR vaddr, unsigned long size, int read,
394 int write, int exec, int modified, void *data)
398 flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD;
400 /* If the memory segment has no permissions set, ignore it, otherwise
401 when we later try to access it for read/write, we'll get an error
402 or jam the kernel. */
403 if (read == 0 && write == 0 && exec == 0 && modified == 0)
407 fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at %s\n",
408 plongest (size), paddress (target_gdbarch (), vaddr));
414 if (write == 0 && modified == 0 && !solib_keep_data_in_core (vaddr, size))
416 /* See if this region of memory lies inside a known file on disk.
417 If so, we can avoid copying its contents by clearing SEC_LOAD. */
418 struct objfile *objfile;
419 struct obj_section *objsec;
421 ALL_OBJSECTIONS (objfile, objsec)
423 bfd *abfd = objfile->obfd;
424 asection *asec = objsec->the_bfd_section;
425 bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd,
427 bfd_vma start = obj_section_addr (objsec) & -align;
428 bfd_vma end = (obj_section_endaddr (objsec) + align - 1) & -align;
430 /* Match if either the entire memory region lies inside the
431 section (i.e. a mapping covering some pages of a large
432 segment) or the entire section lies inside the memory region
433 (i.e. a mapping covering multiple small sections).
435 This BFD was synthesized from reading target memory,
436 we don't want to omit that. */
437 if (objfile->separate_debug_objfile_backlink == NULL
438 && ((vaddr >= start && vaddr + size <= end)
439 || (start >= vaddr && end <= vaddr + size))
440 && !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY))
442 flags &= ~(SEC_LOAD | SEC_HAS_CONTENTS);
443 goto keep; /* Break out of two nested for loops. */
451 flags |= SEC_READONLY;
458 osec = bfd_make_section_anyway_with_flags (obfd, "load", flags);
461 warning (_("Couldn't make gcore segment: %s"),
462 bfd_errmsg (bfd_get_error ()));
468 fprintf_filtered (gdb_stdout, "Save segment, %s bytes at %s\n",
469 plongest (size), paddress (target_gdbarch (), vaddr));
472 bfd_set_section_size (obfd, osec, size);
473 bfd_set_section_vma (obfd, osec, vaddr);
474 bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */
479 objfile_find_memory_regions (find_memory_region_ftype func, void *obfd)
481 /* Use objfile data to create memory sections. */
482 struct objfile *objfile;
483 struct obj_section *objsec;
484 bfd_vma temp_bottom, temp_top;
486 /* Call callback function for each objfile section. */
487 ALL_OBJSECTIONS (objfile, objsec)
489 bfd *ibfd = objfile->obfd;
490 asection *isec = objsec->the_bfd_section;
491 flagword flags = bfd_get_section_flags (ibfd, isec);
493 /* Separate debug info files are irrelevant for gcore. */
494 if (objfile->separate_debug_objfile_backlink != NULL)
497 if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
499 int size = bfd_section_size (ibfd, isec);
502 ret = (*func) (obj_section_addr (objsec), size,
503 1, /* All sections will be readable. */
504 (flags & SEC_READONLY) == 0, /* Writable. */
505 (flags & SEC_CODE) != 0, /* Executable. */
506 1, /* MODIFIED is unknown, pass it as true. */
513 /* Make a stack segment. */
514 if (derive_stack_segment (&temp_bottom, &temp_top))
515 (*func) (temp_bottom, temp_top - temp_bottom,
516 1, /* Stack section will be readable. */
517 1, /* Stack section will be writable. */
518 0, /* Stack section will not be executable. */
519 1, /* Stack section will be modified. */
522 /* Make a heap segment. */
523 if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top))
524 (*func) (temp_bottom, temp_top - temp_bottom,
525 1, /* Heap section will be readable. */
526 1, /* Heap section will be writable. */
527 0, /* Heap section will not be executable. */
528 1, /* Heap section will be modified. */
535 gcore_copy_callback (bfd *obfd, asection *osec, void *ignored)
537 bfd_size_type size, total_size = bfd_section_size (obfd, osec);
539 struct cleanup *old_chain = NULL;
542 /* Read-only sections are marked; we don't have to copy their contents. */
543 if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0)
546 /* Only interested in "load" sections. */
547 if (strncmp ("load", bfd_section_name (obfd, osec), 4) != 0)
550 size = min (total_size, MAX_COPY_BYTES);
551 memhunk = xmalloc (size);
552 old_chain = make_cleanup (xfree, memhunk);
554 while (total_size > 0)
556 if (size > total_size)
559 if (target_read_memory (bfd_section_vma (obfd, osec) + offset,
562 warning (_("Memory read failed for corefile "
563 "section, %s bytes at %s."),
565 paddress (target_gdbarch (), bfd_section_vma (obfd, osec)));
568 if (!bfd_set_section_contents (obfd, osec, memhunk, offset, size))
570 warning (_("Failed to write corefile contents (%s)."),
571 bfd_errmsg (bfd_get_error ()));
579 do_cleanups (old_chain); /* Frees MEMHUNK. */
583 gcore_memory_sections (bfd *obfd)
585 /* Try gdbarch method first, then fall back to target method. */
586 if (!gdbarch_find_memory_regions_p (target_gdbarch ())
587 || gdbarch_find_memory_regions (target_gdbarch (),
588 gcore_create_callback, obfd) != 0)
590 if (target_find_memory_regions (gcore_create_callback, obfd) != 0)
591 return 0; /* FIXME: error return/msg? */
594 /* Record phdrs for section-to-segment mapping. */
595 bfd_map_over_sections (obfd, make_output_phdrs, NULL);
597 /* Copy memory region contents. */
598 bfd_map_over_sections (obfd, gcore_copy_callback, NULL);
603 /* Provide a prototype to silence -Wmissing-prototypes. */
604 extern initialize_file_ftype _initialize_gcore;
607 _initialize_gcore (void)
609 add_com ("generate-core-file", class_files, gcore_command, _("\
610 Save a core file with the current state of the debugged process.\n\
611 Argument is optional filename. Default filename is 'core.<process_id>'."));
613 add_com_alias ("gcore", "generate-core-file", class_files, 1);
614 exec_set_find_memory_regions (objfile_find_memory_regions);