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 = 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 -- helper for gcore_command (exported).
64 Compose and write the corefile data to the core file. */
68 write_gcore_file (bfd *obfd)
70 void *note_data = NULL;
72 asection *note_sec = NULL;
74 /* An external target method must build the notes section. */
75 /* FIXME: uweigand/2011-10-06: All architectures that support core file
76 generation should be converted to gdbarch_make_corefile_notes; at that
77 point, the target vector method can be removed. */
78 if (!gdbarch_make_corefile_notes_p (target_gdbarch ()))
79 note_data = target_make_corefile_notes (obfd, ¬e_size);
81 note_data = gdbarch_make_corefile_notes (target_gdbarch (), obfd, ¬e_size);
83 if (note_data == NULL || note_size == 0)
84 error (_("Target does not support core file generation."));
86 /* Create the note section. */
87 note_sec = bfd_make_section_anyway_with_flags (obfd, "note0",
92 error (_("Failed to create 'note' section for corefile: %s"),
93 bfd_errmsg (bfd_get_error ()));
95 bfd_set_section_vma (obfd, note_sec, 0);
96 bfd_set_section_alignment (obfd, note_sec, 0);
97 bfd_set_section_size (obfd, note_sec, note_size);
99 /* Now create the memory/load sections. */
100 if (gcore_memory_sections (obfd) == 0)
101 error (_("gcore: failed to get corefile memory sections from target."));
103 /* Write out the contents of the note section. */
104 if (!bfd_set_section_contents (obfd, note_sec, note_data, 0, note_size))
105 warning (_("writing note section (%s)"), bfd_errmsg (bfd_get_error ()));
109 do_bfd_delete_cleanup (void *arg)
112 const char *filename = obfd->filename;
118 /* gcore_command -- implements the 'gcore' command.
119 Generate a core file from the inferior process. */
122 gcore_command (char *args, int from_tty)
124 struct cleanup *old_chain;
125 char *corefilename, corefilename_buffer[40];
128 /* No use generating a corefile without a target process. */
129 if (!target_has_execution)
136 /* Default corefile name is "core.PID". */
137 sprintf (corefilename_buffer, "core.%d", PIDGET (inferior_ptid));
138 corefilename = corefilename_buffer;
142 fprintf_filtered (gdb_stdout,
143 "Opening corefile '%s' for output.\n", corefilename);
145 /* Open the output file. */
146 obfd = create_gcore_bfd (corefilename);
148 /* Need a cleanup that will close and delete the file. */
149 old_chain = make_cleanup (do_bfd_delete_cleanup, obfd);
151 /* Call worker function. */
152 write_gcore_file (obfd);
155 fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename);
157 discard_cleanups (old_chain);
158 gdb_bfd_unref (obfd);
162 default_gcore_mach (void)
164 #if 1 /* See if this even matters... */
168 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
171 return bfdarch->mach;
172 if (exec_bfd == NULL)
173 error (_("Can't find default bfd machine type (need execfile)."));
175 return bfd_get_mach (exec_bfd);
179 static enum bfd_architecture
180 default_gcore_arch (void)
182 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
185 return bfdarch->arch;
186 if (exec_bfd == NULL)
187 error (_("Can't find bfd architecture for corefile (need execfile)."));
189 return bfd_get_arch (exec_bfd);
193 default_gcore_target (void)
195 /* The gdbarch may define a target to use for core files. */
196 if (gdbarch_gcore_bfd_target_p (target_gdbarch ()))
197 return gdbarch_gcore_bfd_target (target_gdbarch ());
199 /* Otherwise, try to fall back to the exec_bfd target. This will probably
200 not work for non-ELF targets. */
201 if (exec_bfd == NULL)
204 return bfd_get_target (exec_bfd);
207 /* Derive a reasonable stack segment by unwinding the target stack,
208 and store its limits in *BOTTOM and *TOP. Return non-zero if
212 derive_stack_segment (bfd_vma *bottom, bfd_vma *top)
214 struct frame_info *fi, *tmp_fi;
219 /* Can't succeed without stack and registers. */
220 if (!target_has_stack || !target_has_registers)
223 /* Can't succeed without current frame. */
224 fi = get_current_frame ();
228 /* Save frame pointer of TOS frame. */
229 *top = get_frame_base (fi);
230 /* If current stack pointer is more "inner", use that instead. */
231 if (gdbarch_inner_than (get_frame_arch (fi), get_frame_sp (fi), *top))
232 *top = get_frame_sp (fi);
234 /* Find prev-most frame. */
235 while ((tmp_fi = get_prev_frame (fi)) != NULL)
238 /* Save frame pointer of prev-most frame. */
239 *bottom = get_frame_base (fi);
241 /* Now canonicalize their order, so that BOTTOM is a lower address
242 (as opposed to a lower stack frame). */
255 /* call_target_sbrk --
256 helper function for derive_heap_segment. */
259 call_target_sbrk (int sbrk_arg)
261 struct objfile *sbrk_objf;
262 struct gdbarch *gdbarch;
264 struct value *target_sbrk_arg;
265 struct value *sbrk_fn, *ret;
268 if (lookup_minimal_symbol ("sbrk", NULL, NULL) != NULL)
270 sbrk_fn = find_function_in_inferior ("sbrk", &sbrk_objf);
274 else if (lookup_minimal_symbol ("_sbrk", NULL, NULL) != NULL)
276 sbrk_fn = find_function_in_inferior ("_sbrk", &sbrk_objf);
283 gdbarch = get_objfile_arch (sbrk_objf);
284 target_sbrk_arg = value_from_longest (builtin_type (gdbarch)->builtin_int,
286 gdb_assert (target_sbrk_arg);
287 ret = call_function_by_hand (sbrk_fn, 1, &target_sbrk_arg);
291 tmp = value_as_long (ret);
292 if ((LONGEST) tmp <= 0 || (LONGEST) tmp == 0xffffffff)
299 /* Derive a reasonable heap segment for ABFD by looking at sbrk and
300 the static data sections. Store its limits in *BOTTOM and *TOP.
301 Return non-zero if successful. */
304 derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top)
306 bfd_vma top_of_data_memory = 0;
307 bfd_vma top_of_heap = 0;
308 bfd_size_type sec_size;
315 /* This function depends on being able to call a function in the
317 if (!target_has_execution)
320 /* The following code assumes that the link map is arranged as
321 follows (low to high addresses):
323 ---------------------------------
325 ---------------------------------
326 | data sections (including bss) |
327 ---------------------------------
329 --------------------------------- */
331 for (sec = abfd->sections; sec; sec = sec->next)
333 if (bfd_get_section_flags (abfd, sec) & SEC_DATA
334 || strcmp (".bss", bfd_section_name (abfd, sec)) == 0)
336 sec_vaddr = bfd_get_section_vma (abfd, sec);
337 sec_size = bfd_get_section_size (sec);
338 if (sec_vaddr + sec_size > top_of_data_memory)
339 top_of_data_memory = sec_vaddr + sec_size;
343 top_of_heap = call_target_sbrk (0);
344 if (top_of_heap == (bfd_vma) 0)
347 /* Return results. */
348 if (top_of_heap > top_of_data_memory)
350 *bottom = top_of_data_memory;
355 /* No additional heap space needs to be saved. */
360 make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
365 /* FIXME: these constants may only be applicable for ELF. */
366 if (strncmp (bfd_section_name (obfd, osec), "load", 4) == 0)
368 else if (strncmp (bfd_section_name (obfd, osec), "note", 4) == 0)
373 p_flags |= PF_R; /* Segment is readable. */
374 if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY))
375 p_flags |= PF_W; /* Segment is writable. */
376 if (bfd_get_section_flags (obfd, osec) & SEC_CODE)
377 p_flags |= PF_X; /* Segment is executable. */
379 bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec);
382 /* find_memory_region_ftype implementation. DATA is 'bfd *' for the core file
386 gcore_create_callback (CORE_ADDR vaddr, unsigned long size, int read,
387 int write, int exec, int modified, void *data)
391 flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD;
393 /* If the memory segment has no permissions set, ignore it, otherwise
394 when we later try to access it for read/write, we'll get an error
395 or jam the kernel. */
396 if (read == 0 && write == 0 && exec == 0 && modified == 0)
400 fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at %s\n",
401 plongest (size), paddress (target_gdbarch (), vaddr));
407 if (write == 0 && modified == 0 && !solib_keep_data_in_core (vaddr, size))
409 /* See if this region of memory lies inside a known file on disk.
410 If so, we can avoid copying its contents by clearing SEC_LOAD. */
411 struct objfile *objfile;
412 struct obj_section *objsec;
414 ALL_OBJSECTIONS (objfile, objsec)
416 bfd *abfd = objfile->obfd;
417 asection *asec = objsec->the_bfd_section;
418 bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd,
420 bfd_vma start = obj_section_addr (objsec) & -align;
421 bfd_vma end = (obj_section_endaddr (objsec) + align - 1) & -align;
423 /* Match if either the entire memory region lies inside the
424 section (i.e. a mapping covering some pages of a large
425 segment) or the entire section lies inside the memory region
426 (i.e. a mapping covering multiple small sections).
428 This BFD was synthesized from reading target memory,
429 we don't want to omit that. */
430 if (((vaddr >= start && vaddr + size <= end)
431 || (start >= vaddr && end <= vaddr + size))
432 && !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY))
434 flags &= ~(SEC_LOAD | SEC_HAS_CONTENTS);
435 goto keep; /* Break out of two nested for loops. */
443 flags |= SEC_READONLY;
450 osec = bfd_make_section_anyway_with_flags (obfd, "load", flags);
453 warning (_("Couldn't make gcore segment: %s"),
454 bfd_errmsg (bfd_get_error ()));
460 fprintf_filtered (gdb_stdout, "Save segment, %s bytes at %s\n",
461 plongest (size), paddress (target_gdbarch (), vaddr));
464 bfd_set_section_size (obfd, osec, size);
465 bfd_set_section_vma (obfd, osec, vaddr);
466 bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */
471 objfile_find_memory_regions (find_memory_region_ftype func, void *obfd)
473 /* Use objfile data to create memory sections. */
474 struct objfile *objfile;
475 struct obj_section *objsec;
476 bfd_vma temp_bottom, temp_top;
478 /* Call callback function for each objfile section. */
479 ALL_OBJSECTIONS (objfile, objsec)
481 bfd *ibfd = objfile->obfd;
482 asection *isec = objsec->the_bfd_section;
483 flagword flags = bfd_get_section_flags (ibfd, isec);
485 /* Separate debug info files are irrelevant for gcore. */
486 if (objfile->separate_debug_objfile_backlink != NULL)
489 if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
491 int size = bfd_section_size (ibfd, isec);
494 ret = (*func) (obj_section_addr (objsec), size,
495 1, /* All sections will be readable. */
496 (flags & SEC_READONLY) == 0, /* Writable. */
497 (flags & SEC_CODE) != 0, /* Executable. */
498 1, /* MODIFIED is unknown, pass it as true. */
505 /* Make a stack segment. */
506 if (derive_stack_segment (&temp_bottom, &temp_top))
507 (*func) (temp_bottom, temp_top - temp_bottom,
508 1, /* Stack section will be readable. */
509 1, /* Stack section will be writable. */
510 0, /* Stack section will not be executable. */
511 1, /* Stack section will be modified. */
514 /* Make a heap segment. */
515 if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top))
516 (*func) (temp_bottom, temp_top - temp_bottom,
517 1, /* Heap section will be readable. */
518 1, /* Heap section will be writable. */
519 0, /* Heap section will not be executable. */
520 1, /* Heap section will be modified. */
527 gcore_copy_callback (bfd *obfd, asection *osec, void *ignored)
529 bfd_size_type size, total_size = bfd_section_size (obfd, osec);
531 struct cleanup *old_chain = NULL;
534 /* Read-only sections are marked; we don't have to copy their contents. */
535 if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0)
538 /* Only interested in "load" sections. */
539 if (strncmp ("load", bfd_section_name (obfd, osec), 4) != 0)
542 size = min (total_size, MAX_COPY_BYTES);
543 memhunk = xmalloc (size);
544 old_chain = make_cleanup (xfree, memhunk);
546 while (total_size > 0)
548 if (size > total_size)
551 if (target_read_memory (bfd_section_vma (obfd, osec) + offset,
554 warning (_("Memory read failed for corefile "
555 "section, %s bytes at %s."),
557 paddress (target_gdbarch (), bfd_section_vma (obfd, osec)));
560 if (!bfd_set_section_contents (obfd, osec, memhunk, offset, size))
562 warning (_("Failed to write corefile contents (%s)."),
563 bfd_errmsg (bfd_get_error ()));
571 do_cleanups (old_chain); /* Frees MEMHUNK. */
575 gcore_memory_sections (bfd *obfd)
577 /* Try gdbarch method first, then fall back to target method. */
578 if (!gdbarch_find_memory_regions_p (target_gdbarch ())
579 || gdbarch_find_memory_regions (target_gdbarch (),
580 gcore_create_callback, obfd) != 0)
582 if (target_find_memory_regions (gcore_create_callback, obfd) != 0)
583 return 0; /* FIXME: error return/msg? */
586 /* Record phdrs for section-to-segment mapping. */
587 bfd_map_over_sections (obfd, make_output_phdrs, NULL);
589 /* Copy memory region contents. */
590 bfd_map_over_sections (obfd, gcore_copy_callback, NULL);
595 /* Provide a prototype to silence -Wmissing-prototypes. */
596 extern initialize_file_ftype _initialize_gcore;
599 _initialize_gcore (void)
601 add_com ("generate-core-file", class_files, gcore_command, _("\
602 Save a core file with the current state of the debugged process.\n\
603 Argument is optional filename. Default filename is 'core.<process_id>'."));
605 add_com_alias ("gcore", "generate-core-file", class_files, 1);
606 exec_set_find_memory_regions (objfile_find_memory_regions);