1 /* Generate a core file for the inferior process.
3 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
4 2011 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
29 #include "arch-utils.h"
30 #include "completer.h"
32 #include "cli/cli-decode.h"
33 #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 ());
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 note_data = target_make_corefile_notes (obfd, ¬e_size);
77 /* Create the note section. */
78 if (note_data != NULL && note_size != 0)
80 note_sec = bfd_make_section_anyway_with_flags (obfd, "note0",
85 error (_("Failed to create 'note' section for corefile: %s"),
86 bfd_errmsg (bfd_get_error ()));
88 bfd_set_section_vma (obfd, note_sec, 0);
89 bfd_set_section_alignment (obfd, note_sec, 0);
90 bfd_set_section_size (obfd, note_sec, note_size);
93 /* Now create the memory/load sections. */
94 if (gcore_memory_sections (obfd) == 0)
95 error (_("gcore: failed to get corefile memory sections from target."));
97 /* Write out the contents of the note section. */
98 if (note_data != NULL && note_size != 0)
100 if (!bfd_set_section_contents (obfd, note_sec, note_data, 0, note_size))
101 warning (_("writing note section (%s)"),
102 bfd_errmsg (bfd_get_error ()));
107 do_bfd_delete_cleanup (void *arg)
110 const char *filename = obfd->filename;
116 /* gcore_command -- implements the 'gcore' command.
117 Generate a core file from the inferior process. */
120 gcore_command (char *args, int from_tty)
122 struct cleanup *old_chain;
123 char *corefilename, corefilename_buffer[40];
126 /* No use generating a corefile without a target process. */
127 if (!target_has_execution)
134 /* Default corefile name is "core.PID". */
135 sprintf (corefilename_buffer, "core.%d", PIDGET (inferior_ptid));
136 corefilename = corefilename_buffer;
140 fprintf_filtered (gdb_stdout,
141 "Opening corefile '%s' for output.\n", corefilename);
143 /* Open the output file. */
144 obfd = create_gcore_bfd (corefilename);
146 /* Need a cleanup that will close and delete the file. */
147 old_chain = make_cleanup (do_bfd_delete_cleanup, obfd);
149 /* Call worker function. */
150 write_gcore_file (obfd);
153 fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename);
155 discard_cleanups (old_chain);
160 default_gcore_mach (void)
162 #if 1 /* See if this even matters... */
166 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch);
169 return bfdarch->mach;
170 if (exec_bfd == NULL)
171 error (_("Can't find default bfd machine type (need execfile)."));
173 return bfd_get_mach (exec_bfd);
177 static enum bfd_architecture
178 default_gcore_arch (void)
180 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch);
183 return bfdarch->arch;
184 if (exec_bfd == NULL)
185 error (_("Can't find bfd architecture for corefile (need execfile)."));
187 return bfd_get_arch (exec_bfd);
191 default_gcore_target (void)
193 /* The gdbarch may define a target to use for core files. */
194 if (gdbarch_gcore_bfd_target_p (target_gdbarch))
195 return gdbarch_gcore_bfd_target (target_gdbarch);
197 /* Otherwise, try to fall back to the exec_bfd target. This will probably
198 not work for non-ELF targets. */
199 if (exec_bfd == NULL)
202 return bfd_get_target (exec_bfd);
205 /* Derive a reasonable stack segment by unwinding the target stack,
206 and store its limits in *BOTTOM and *TOP. Return non-zero if
210 derive_stack_segment (bfd_vma *bottom, bfd_vma *top)
212 struct frame_info *fi, *tmp_fi;
217 /* Can't succeed without stack and registers. */
218 if (!target_has_stack || !target_has_registers)
221 /* Can't succeed without current frame. */
222 fi = get_current_frame ();
226 /* Save frame pointer of TOS frame. */
227 *top = get_frame_base (fi);
228 /* If current stack pointer is more "inner", use that instead. */
229 if (gdbarch_inner_than (get_frame_arch (fi), get_frame_sp (fi), *top))
230 *top = get_frame_sp (fi);
232 /* Find prev-most frame. */
233 while ((tmp_fi = get_prev_frame (fi)) != NULL)
236 /* Save frame pointer of prev-most frame. */
237 *bottom = get_frame_base (fi);
239 /* Now canonicalize their order, so that BOTTOM is a lower address
240 (as opposed to a lower stack frame). */
253 /* call_target_sbrk --
254 helper function for derive_heap_segment. */
257 call_target_sbrk (int sbrk_arg)
259 struct objfile *sbrk_objf;
260 struct gdbarch *gdbarch;
262 struct value *target_sbrk_arg;
263 struct value *sbrk_fn, *ret;
266 if (lookup_minimal_symbol ("sbrk", NULL, NULL) != NULL)
268 sbrk_fn = find_function_in_inferior ("sbrk", &sbrk_objf);
272 else if (lookup_minimal_symbol ("_sbrk", NULL, NULL) != NULL)
274 sbrk_fn = find_function_in_inferior ("_sbrk", &sbrk_objf);
281 gdbarch = get_objfile_arch (sbrk_objf);
282 target_sbrk_arg = value_from_longest (builtin_type (gdbarch)->builtin_int,
284 gdb_assert (target_sbrk_arg);
285 ret = call_function_by_hand (sbrk_fn, 1, &target_sbrk_arg);
289 tmp = value_as_long (ret);
290 if ((LONGEST) tmp <= 0 || (LONGEST) tmp == 0xffffffff)
297 /* Derive a reasonable heap segment for ABFD by looking at sbrk and
298 the static data sections. Store its limits in *BOTTOM and *TOP.
299 Return non-zero if successful. */
302 derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top)
304 bfd_vma top_of_data_memory = 0;
305 bfd_vma top_of_heap = 0;
306 bfd_size_type sec_size;
313 /* This function depends on being able to call a function in the
315 if (!target_has_execution)
318 /* The following code assumes that the link map is arranged as
319 follows (low to high addresses):
321 ---------------------------------
323 ---------------------------------
324 | data sections (including bss) |
325 ---------------------------------
327 --------------------------------- */
329 for (sec = abfd->sections; sec; sec = sec->next)
331 if (bfd_get_section_flags (abfd, sec) & SEC_DATA
332 || strcmp (".bss", bfd_section_name (abfd, sec)) == 0)
334 sec_vaddr = bfd_get_section_vma (abfd, sec);
335 sec_size = bfd_get_section_size (sec);
336 if (sec_vaddr + sec_size > top_of_data_memory)
337 top_of_data_memory = sec_vaddr + sec_size;
341 top_of_heap = call_target_sbrk (0);
342 if (top_of_heap == (bfd_vma) 0)
345 /* Return results. */
346 if (top_of_heap > top_of_data_memory)
348 *bottom = top_of_data_memory;
353 /* No additional heap space needs to be saved. */
358 make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
363 /* FIXME: these constants may only be applicable for ELF. */
364 if (strncmp (bfd_section_name (obfd, osec), "load", 4) == 0)
366 else if (strncmp (bfd_section_name (obfd, osec), "note", 4) == 0)
371 p_flags |= PF_R; /* Segment is readable. */
372 if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY))
373 p_flags |= PF_W; /* Segment is writable. */
374 if (bfd_get_section_flags (obfd, osec) & SEC_CODE)
375 p_flags |= PF_X; /* Segment is executable. */
377 bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec);
381 gcore_create_callback (CORE_ADDR vaddr, unsigned long size,
382 int read, int write, int exec, void *data)
386 flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD;
388 /* If the memory segment has no permissions set, ignore it, otherwise
389 when we later try to access it for read/write, we'll get an error
390 or jam the kernel. */
391 if (read == 0 && write == 0 && exec == 0)
395 fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at %s\n",
396 plongest (size), paddress (target_gdbarch, vaddr));
402 if (write == 0 && !solib_keep_data_in_core (vaddr, size))
404 /* See if this region of memory lies inside a known file on disk.
405 If so, we can avoid copying its contents by clearing SEC_LOAD. */
406 struct objfile *objfile;
407 struct obj_section *objsec;
409 ALL_OBJSECTIONS (objfile, objsec)
411 bfd *abfd = objfile->obfd;
412 asection *asec = objsec->the_bfd_section;
413 bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd,
415 bfd_vma start = obj_section_addr (objsec) & -align;
416 bfd_vma end = (obj_section_endaddr (objsec) + align - 1) & -align;
418 /* Match if either the entire memory region lies inside the
419 section (i.e. a mapping covering some pages of a large
420 segment) or the entire section lies inside the memory region
421 (i.e. a mapping covering multiple small sections).
423 This BFD was synthesized from reading target memory,
424 we don't want to omit that. */
425 if (((vaddr >= start && vaddr + size <= end)
426 || (start >= vaddr && end <= vaddr + size))
427 && !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY))
429 flags &= ~(SEC_LOAD | SEC_HAS_CONTENTS);
430 goto keep; /* break out of two nested for loops */
435 flags |= SEC_READONLY;
443 osec = bfd_make_section_anyway_with_flags (obfd, "load", flags);
446 warning (_("Couldn't make gcore segment: %s"),
447 bfd_errmsg (bfd_get_error ()));
453 fprintf_filtered (gdb_stdout, "Save segment, %s bytes at %s\n",
454 plongest (size), paddress (target_gdbarch, vaddr));
457 bfd_set_section_size (obfd, osec, size);
458 bfd_set_section_vma (obfd, osec, vaddr);
459 bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */
464 objfile_find_memory_regions (find_memory_region_ftype func, void *obfd)
466 /* Use objfile data to create memory sections. */
467 struct objfile *objfile;
468 struct obj_section *objsec;
469 bfd_vma temp_bottom, temp_top;
471 /* Call callback function for each objfile section. */
472 ALL_OBJSECTIONS (objfile, objsec)
474 bfd *ibfd = objfile->obfd;
475 asection *isec = objsec->the_bfd_section;
476 flagword flags = bfd_get_section_flags (ibfd, isec);
478 if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
480 int size = bfd_section_size (ibfd, isec);
483 ret = (*func) (obj_section_addr (objsec), size,
484 1, /* All sections will be readable. */
485 (flags & SEC_READONLY) == 0, /* Writable. */
486 (flags & SEC_CODE) != 0, /* Executable. */
493 /* Make a stack segment. */
494 if (derive_stack_segment (&temp_bottom, &temp_top))
495 (*func) (temp_bottom, temp_top - temp_bottom,
496 1, /* Stack section will be readable. */
497 1, /* Stack section will be writable. */
498 0, /* Stack section will not be executable. */
501 /* Make a heap segment. */
502 if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top))
503 (*func) (temp_bottom, temp_top - temp_bottom,
504 1, /* Heap section will be readable. */
505 1, /* Heap section will be writable. */
506 0, /* Heap section will not be executable. */
513 gcore_copy_callback (bfd *obfd, asection *osec, void *ignored)
515 bfd_size_type size, total_size = bfd_section_size (obfd, osec);
517 struct cleanup *old_chain = NULL;
520 /* Read-only sections are marked; we don't have to copy their contents. */
521 if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0)
524 /* Only interested in "load" sections. */
525 if (strncmp ("load", bfd_section_name (obfd, osec), 4) != 0)
528 size = min (total_size, MAX_COPY_BYTES);
529 memhunk = xmalloc (size);
530 old_chain = make_cleanup (xfree, memhunk);
532 while (total_size > 0)
534 if (size > total_size)
537 if (target_read_memory (bfd_section_vma (obfd, osec) + offset,
540 warning (_("Memory read failed for corefile "
541 "section, %s bytes at %s."),
543 paddress (target_gdbarch, bfd_section_vma (obfd, osec)));
546 if (!bfd_set_section_contents (obfd, osec, memhunk, offset, size))
548 warning (_("Failed to write corefile contents (%s)."),
549 bfd_errmsg (bfd_get_error ()));
557 do_cleanups (old_chain); /* Frees MEMHUNK. */
561 gcore_memory_sections (bfd *obfd)
563 if (target_find_memory_regions (gcore_create_callback, obfd) != 0)
564 return 0; /* FIXME: error return/msg? */
566 /* Record phdrs for section-to-segment mapping. */
567 bfd_map_over_sections (obfd, make_output_phdrs, NULL);
569 /* Copy memory region contents. */
570 bfd_map_over_sections (obfd, gcore_copy_callback, NULL);
575 /* Provide a prototype to silence -Wmissing-prototypes. */
576 extern initialize_file_ftype _initialize_gcore;
579 _initialize_gcore (void)
581 add_com ("generate-core-file", class_files, gcore_command, _("\
582 Save a core file with the current state of the debugged process.\n\
583 Argument is optional filename. Default filename is 'core.<process_id>'."));
585 add_com_alias ("gcore", "generate-core-file", class_files, 1);
586 exec_set_find_memory_regions (objfile_find_memory_regions);