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 volatile struct gdb_exception except;
119 target_prepare_to_generate_core ();
121 TRY_CATCH (except, RETURN_MASK_ALL)
122 write_gcore_file_1 (obfd);
124 target_done_generating_core ();
126 if (except.reason < 0)
127 throw_exception (except);
131 do_bfd_delete_cleanup (void *arg)
134 const char *filename = obfd->filename;
140 /* gcore_command -- implements the 'gcore' command.
141 Generate a core file from the inferior process. */
144 gcore_command (char *args, int from_tty)
146 struct cleanup *filename_chain;
147 struct cleanup *bfd_chain;
151 /* No use generating a corefile without a target process. */
152 if (!target_has_execution)
156 corefilename = tilde_expand (args);
159 /* Default corefile name is "core.PID". */
160 corefilename = xstrprintf ("core.%d", ptid_get_pid (inferior_ptid));
162 filename_chain = make_cleanup (xfree, corefilename);
165 fprintf_filtered (gdb_stdout,
166 "Opening corefile '%s' for output.\n", corefilename);
168 /* Open the output file. */
169 obfd = create_gcore_bfd (corefilename);
171 /* Need a cleanup that will close and delete the file. */
172 bfd_chain = make_cleanup (do_bfd_delete_cleanup, obfd);
174 /* Call worker function. */
175 write_gcore_file (obfd);
178 discard_cleanups (bfd_chain);
179 gdb_bfd_unref (obfd);
181 fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename);
182 do_cleanups (filename_chain);
186 default_gcore_mach (void)
188 #if 1 /* See if this even matters... */
192 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
195 return bfdarch->mach;
196 if (exec_bfd == NULL)
197 error (_("Can't find default bfd machine type (need execfile)."));
199 return bfd_get_mach (exec_bfd);
203 static enum bfd_architecture
204 default_gcore_arch (void)
206 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
209 return bfdarch->arch;
210 if (exec_bfd == NULL)
211 error (_("Can't find bfd architecture for corefile (need execfile)."));
213 return bfd_get_arch (exec_bfd);
217 default_gcore_target (void)
219 /* The gdbarch may define a target to use for core files. */
220 if (gdbarch_gcore_bfd_target_p (target_gdbarch ()))
221 return gdbarch_gcore_bfd_target (target_gdbarch ());
223 /* Otherwise, try to fall back to the exec_bfd target. This will probably
224 not work for non-ELF targets. */
225 if (exec_bfd == NULL)
228 return bfd_get_target (exec_bfd);
231 /* Derive a reasonable stack segment by unwinding the target stack,
232 and store its limits in *BOTTOM and *TOP. Return non-zero if
236 derive_stack_segment (bfd_vma *bottom, bfd_vma *top)
238 struct frame_info *fi, *tmp_fi;
243 /* Can't succeed without stack and registers. */
244 if (!target_has_stack || !target_has_registers)
247 /* Can't succeed without current frame. */
248 fi = get_current_frame ();
252 /* Save frame pointer of TOS frame. */
253 *top = get_frame_base (fi);
254 /* If current stack pointer is more "inner", use that instead. */
255 if (gdbarch_inner_than (get_frame_arch (fi), get_frame_sp (fi), *top))
256 *top = get_frame_sp (fi);
258 /* Find prev-most frame. */
259 while ((tmp_fi = get_prev_frame (fi)) != NULL)
262 /* Save frame pointer of prev-most frame. */
263 *bottom = get_frame_base (fi);
265 /* Now canonicalize their order, so that BOTTOM is a lower address
266 (as opposed to a lower stack frame). */
279 /* call_target_sbrk --
280 helper function for derive_heap_segment. */
283 call_target_sbrk (int sbrk_arg)
285 struct objfile *sbrk_objf;
286 struct gdbarch *gdbarch;
288 struct value *target_sbrk_arg;
289 struct value *sbrk_fn, *ret;
292 if (lookup_minimal_symbol ("sbrk", NULL, NULL).minsym != NULL)
294 sbrk_fn = find_function_in_inferior ("sbrk", &sbrk_objf);
298 else if (lookup_minimal_symbol ("_sbrk", NULL, NULL).minsym != NULL)
300 sbrk_fn = find_function_in_inferior ("_sbrk", &sbrk_objf);
307 gdbarch = get_objfile_arch (sbrk_objf);
308 target_sbrk_arg = value_from_longest (builtin_type (gdbarch)->builtin_int,
310 gdb_assert (target_sbrk_arg);
311 ret = call_function_by_hand (sbrk_fn, 1, &target_sbrk_arg);
315 tmp = value_as_long (ret);
316 if ((LONGEST) tmp <= 0 || (LONGEST) tmp == 0xffffffff)
323 /* Derive a reasonable heap segment for ABFD by looking at sbrk and
324 the static data sections. Store its limits in *BOTTOM and *TOP.
325 Return non-zero if successful. */
328 derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top)
330 bfd_vma top_of_data_memory = 0;
331 bfd_vma top_of_heap = 0;
332 bfd_size_type sec_size;
339 /* This function depends on being able to call a function in the
341 if (!target_has_execution)
344 /* The following code assumes that the link map is arranged as
345 follows (low to high addresses):
347 ---------------------------------
349 ---------------------------------
350 | data sections (including bss) |
351 ---------------------------------
353 --------------------------------- */
355 for (sec = abfd->sections; sec; sec = sec->next)
357 if (bfd_get_section_flags (abfd, sec) & SEC_DATA
358 || strcmp (".bss", bfd_section_name (abfd, sec)) == 0)
360 sec_vaddr = bfd_get_section_vma (abfd, sec);
361 sec_size = bfd_get_section_size (sec);
362 if (sec_vaddr + sec_size > top_of_data_memory)
363 top_of_data_memory = sec_vaddr + sec_size;
367 top_of_heap = call_target_sbrk (0);
368 if (top_of_heap == (bfd_vma) 0)
371 /* Return results. */
372 if (top_of_heap > top_of_data_memory)
374 *bottom = top_of_data_memory;
379 /* No additional heap space needs to be saved. */
384 make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
389 /* FIXME: these constants may only be applicable for ELF. */
390 if (startswith (bfd_section_name (obfd, osec), "load"))
392 else if (startswith (bfd_section_name (obfd, osec), "note"))
397 p_flags |= PF_R; /* Segment is readable. */
398 if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY))
399 p_flags |= PF_W; /* Segment is writable. */
400 if (bfd_get_section_flags (obfd, osec) & SEC_CODE)
401 p_flags |= PF_X; /* Segment is executable. */
403 bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec);
406 /* find_memory_region_ftype implementation. DATA is 'bfd *' for the core file
410 gcore_create_callback (CORE_ADDR vaddr, unsigned long size, int read,
411 int write, int exec, int modified, void *data)
415 flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD;
417 /* If the memory segment has no permissions set, ignore it, otherwise
418 when we later try to access it for read/write, we'll get an error
419 or jam the kernel. */
420 if (read == 0 && write == 0 && exec == 0 && modified == 0)
424 fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at %s\n",
425 plongest (size), paddress (target_gdbarch (), vaddr));
431 if (write == 0 && modified == 0 && !solib_keep_data_in_core (vaddr, size))
433 /* See if this region of memory lies inside a known file on disk.
434 If so, we can avoid copying its contents by clearing SEC_LOAD. */
435 struct objfile *objfile;
436 struct obj_section *objsec;
438 ALL_OBJSECTIONS (objfile, objsec)
440 bfd *abfd = objfile->obfd;
441 asection *asec = objsec->the_bfd_section;
442 bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd,
444 bfd_vma start = obj_section_addr (objsec) & -align;
445 bfd_vma end = (obj_section_endaddr (objsec) + align - 1) & -align;
447 /* Match if either the entire memory region lies inside the
448 section (i.e. a mapping covering some pages of a large
449 segment) or the entire section lies inside the memory region
450 (i.e. a mapping covering multiple small sections).
452 This BFD was synthesized from reading target memory,
453 we don't want to omit that. */
454 if (objfile->separate_debug_objfile_backlink == NULL
455 && ((vaddr >= start && vaddr + size <= end)
456 || (start >= vaddr && end <= vaddr + size))
457 && !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY))
459 flags &= ~(SEC_LOAD | SEC_HAS_CONTENTS);
460 goto keep; /* Break out of two nested for loops. */
468 flags |= SEC_READONLY;
475 osec = bfd_make_section_anyway_with_flags (obfd, "load", flags);
478 warning (_("Couldn't make gcore segment: %s"),
479 bfd_errmsg (bfd_get_error ()));
485 fprintf_filtered (gdb_stdout, "Save segment, %s bytes at %s\n",
486 plongest (size), paddress (target_gdbarch (), vaddr));
489 bfd_set_section_size (obfd, osec, size);
490 bfd_set_section_vma (obfd, osec, vaddr);
491 bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */
496 objfile_find_memory_regions (struct target_ops *self,
497 find_memory_region_ftype func, void *obfd)
499 /* Use objfile data to create memory sections. */
500 struct objfile *objfile;
501 struct obj_section *objsec;
502 bfd_vma temp_bottom, temp_top;
504 /* Call callback function for each objfile section. */
505 ALL_OBJSECTIONS (objfile, objsec)
507 bfd *ibfd = objfile->obfd;
508 asection *isec = objsec->the_bfd_section;
509 flagword flags = bfd_get_section_flags (ibfd, isec);
511 /* Separate debug info files are irrelevant for gcore. */
512 if (objfile->separate_debug_objfile_backlink != NULL)
515 if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
517 int size = bfd_section_size (ibfd, isec);
520 ret = (*func) (obj_section_addr (objsec), size,
521 1, /* All sections will be readable. */
522 (flags & SEC_READONLY) == 0, /* Writable. */
523 (flags & SEC_CODE) != 0, /* Executable. */
524 1, /* MODIFIED is unknown, pass it as true. */
531 /* Make a stack segment. */
532 if (derive_stack_segment (&temp_bottom, &temp_top))
533 (*func) (temp_bottom, temp_top - temp_bottom,
534 1, /* Stack section will be readable. */
535 1, /* Stack section will be writable. */
536 0, /* Stack section will not be executable. */
537 1, /* Stack section will be modified. */
540 /* Make a heap segment. */
541 if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top))
542 (*func) (temp_bottom, temp_top - temp_bottom,
543 1, /* Heap section will be readable. */
544 1, /* Heap section will be writable. */
545 0, /* Heap section will not be executable. */
546 1, /* Heap section will be modified. */
553 gcore_copy_callback (bfd *obfd, asection *osec, void *ignored)
555 bfd_size_type size, total_size = bfd_section_size (obfd, osec);
557 struct cleanup *old_chain = NULL;
560 /* Read-only sections are marked; we don't have to copy their contents. */
561 if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0)
564 /* Only interested in "load" sections. */
565 if (!startswith (bfd_section_name (obfd, osec), "load"))
568 size = min (total_size, MAX_COPY_BYTES);
569 memhunk = xmalloc (size);
570 old_chain = make_cleanup (xfree, memhunk);
572 while (total_size > 0)
574 if (size > total_size)
577 if (target_read_memory (bfd_section_vma (obfd, osec) + offset,
580 warning (_("Memory read failed for corefile "
581 "section, %s bytes at %s."),
583 paddress (target_gdbarch (), bfd_section_vma (obfd, osec)));
586 if (!bfd_set_section_contents (obfd, osec, memhunk, offset, size))
588 warning (_("Failed to write corefile contents (%s)."),
589 bfd_errmsg (bfd_get_error ()));
597 do_cleanups (old_chain); /* Frees MEMHUNK. */
601 gcore_memory_sections (bfd *obfd)
603 /* Try gdbarch method first, then fall back to target method. */
604 if (!gdbarch_find_memory_regions_p (target_gdbarch ())
605 || gdbarch_find_memory_regions (target_gdbarch (),
606 gcore_create_callback, obfd) != 0)
608 if (target_find_memory_regions (gcore_create_callback, obfd) != 0)
609 return 0; /* FIXME: error return/msg? */
612 /* Record phdrs for section-to-segment mapping. */
613 bfd_map_over_sections (obfd, make_output_phdrs, NULL);
615 /* Copy memory region contents. */
616 bfd_map_over_sections (obfd, gcore_copy_callback, NULL);
621 /* Provide a prototype to silence -Wmissing-prototypes. */
622 extern initialize_file_ftype _initialize_gcore;
625 _initialize_gcore (void)
627 add_com ("generate-core-file", class_files, gcore_command, _("\
628 Save a core file with the current state of the debugged process.\n\
629 Argument is optional filename. Default filename is 'core.<process_id>'."));
631 add_com_alias ("gcore", "generate-core-file", class_files, 1);