1 /* Generate a core file for the inferior process.
3 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
4 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 "cli/cli-decode.h"
31 #include "gdb_assert.h"
33 /* The largest amount of memory to read from the target at once. We
34 must throttle it to limit the amount of memory used by GDB during
35 generate-core-file for programs with large resident data. */
36 #define MAX_COPY_BYTES (1024 * 1024)
38 static char *default_gcore_target (void);
39 static enum bfd_architecture default_gcore_arch (void);
40 static unsigned long default_gcore_mach (void);
41 static int gcore_memory_sections (bfd *);
43 /* Generate a core file from the inferior process. */
46 gcore_command (char *args, int from_tty)
48 struct cleanup *old_chain;
49 char *corefilename, corefilename_buffer[40];
50 asection *note_sec = NULL;
52 void *note_data = NULL;
55 /* No use generating a corefile without a target process. */
56 if (!target_has_execution)
63 /* Default corefile name is "core.PID". */
64 sprintf (corefilename_buffer, "core.%d", PIDGET (inferior_ptid));
65 corefilename = corefilename_buffer;
69 fprintf_filtered (gdb_stdout,
70 "Opening corefile '%s' for output.\n", corefilename);
72 /* Open the output file. */
73 obfd = bfd_openw (corefilename, default_gcore_target ());
75 error (_("Failed to open '%s' for output."), corefilename);
77 /* Need a cleanup that will close the file (FIXME: delete it?). */
78 old_chain = make_cleanup_bfd_close (obfd);
80 bfd_set_format (obfd, bfd_core);
81 bfd_set_arch_mach (obfd, default_gcore_arch (), default_gcore_mach ());
83 /* An external target method must build the notes section. */
84 note_data = target_make_corefile_notes (obfd, ¬e_size);
86 /* Create the note section. */
87 if (note_data != NULL && note_size != 0)
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);
102 /* Now create the memory/load sections. */
103 if (gcore_memory_sections (obfd) == 0)
104 error (_("gcore: failed to get corefile memory sections from target."));
106 /* Write out the contents of the note section. */
107 if (note_data != NULL && note_size != 0)
109 if (!bfd_set_section_contents (obfd, note_sec, note_data, 0, note_size))
110 warning (_("writing note section (%s)"), bfd_errmsg (bfd_get_error ()));
114 fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename);
116 /* Clean-ups will close the output file and free malloc memory. */
117 do_cleanups (old_chain);
122 default_gcore_mach (void)
124 #if 1 /* See if this even matters... */
128 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (current_gdbarch);
131 return bfdarch->mach;
132 if (exec_bfd == NULL)
133 error (_("Can't find default bfd machine type (need execfile)."));
135 return bfd_get_mach (exec_bfd);
139 static enum bfd_architecture
140 default_gcore_arch (void)
142 const struct bfd_arch_info * bfdarch = gdbarch_bfd_arch_info
146 return bfdarch->arch;
147 if (exec_bfd == NULL)
148 error (_("Can't find bfd architecture for corefile (need execfile)."));
150 return bfd_get_arch (exec_bfd);
154 default_gcore_target (void)
156 /* FIXME: This may only work for ELF targets. */
157 if (exec_bfd == NULL)
160 return bfd_get_target (exec_bfd);
163 /* Derive a reasonable stack segment by unwinding the target stack,
164 and store its limits in *BOTTOM and *TOP. Return non-zero if
168 derive_stack_segment (bfd_vma *bottom, bfd_vma *top)
170 struct frame_info *fi, *tmp_fi;
175 /* Can't succeed without stack and registers. */
176 if (!target_has_stack || !target_has_registers)
179 /* Can't succeed without current frame. */
180 fi = get_current_frame ();
184 /* Save frame pointer of TOS frame. */
185 *top = get_frame_base (fi);
186 /* If current stack pointer is more "inner", use that instead. */
187 if (gdbarch_inner_than (get_frame_arch (fi), get_frame_sp (fi), *top))
188 *top = get_frame_sp (fi);
190 /* Find prev-most frame. */
191 while ((tmp_fi = get_prev_frame (fi)) != NULL)
194 /* Save frame pointer of prev-most frame. */
195 *bottom = get_frame_base (fi);
197 /* Now canonicalize their order, so that BOTTOM is a lower address
198 (as opposed to a lower stack frame). */
211 /* Derive a reasonable heap segment for ABFD by looking at sbrk and
212 the static data sections. Store its limits in *BOTTOM and *TOP.
213 Return non-zero if successful. */
216 derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top)
218 bfd_vma top_of_data_memory = 0;
219 bfd_vma top_of_heap = 0;
220 bfd_size_type sec_size;
221 struct value *zero, *sbrk;
228 /* This function depends on being able to call a function in the
230 if (!target_has_execution)
233 /* The following code assumes that the link map is arranged as
234 follows (low to high addresses):
236 ---------------------------------
238 ---------------------------------
239 | data sections (including bss) |
240 ---------------------------------
242 --------------------------------- */
244 for (sec = abfd->sections; sec; sec = sec->next)
246 if (bfd_get_section_flags (abfd, sec) & SEC_DATA
247 || strcmp (".bss", bfd_section_name (abfd, sec)) == 0)
249 sec_vaddr = bfd_get_section_vma (abfd, sec);
250 sec_size = bfd_get_section_size (sec);
251 if (sec_vaddr + sec_size > top_of_data_memory)
252 top_of_data_memory = sec_vaddr + sec_size;
256 /* Now get the top-of-heap by calling sbrk in the inferior. */
257 if (lookup_minimal_symbol ("sbrk", NULL, NULL) != NULL)
259 sbrk = find_function_in_inferior ("sbrk");
263 else if (lookup_minimal_symbol ("_sbrk", NULL, NULL) != NULL)
265 sbrk = find_function_in_inferior ("_sbrk");
272 zero = value_from_longest (builtin_type_int, 0);
274 sbrk = call_function_by_hand (sbrk, 1, &zero);
277 top_of_heap = value_as_long (sbrk);
279 /* Return results. */
280 if (top_of_heap > top_of_data_memory)
282 *bottom = top_of_data_memory;
287 /* No additional heap space needs to be saved. */
292 make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
297 /* FIXME: these constants may only be applicable for ELF. */
298 if (strncmp (bfd_section_name (obfd, osec), "load", 4) == 0)
303 p_flags |= PF_R; /* Segment is readable. */
304 if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY))
305 p_flags |= PF_W; /* Segment is writable. */
306 if (bfd_get_section_flags (obfd, osec) & SEC_CODE)
307 p_flags |= PF_X; /* Segment is executable. */
309 bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec);
313 gcore_create_callback (CORE_ADDR vaddr, unsigned long size,
314 int read, int write, int exec, void *data)
318 flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD;
320 /* If the memory segment has no permissions set, ignore it, otherwise
321 when we later try to access it for read/write, we'll get an error
322 or jam the kernel. */
323 if (read == 0 && write == 0 && exec == 0)
327 fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at 0x%s\n",
328 plongest (size), paddr_nz (vaddr));
336 /* See if this region of memory lies inside a known file on disk.
337 If so, we can avoid copying its contents by clearing SEC_LOAD. */
338 struct objfile *objfile;
339 struct obj_section *objsec;
341 ALL_OBJSECTIONS (objfile, objsec)
343 bfd *abfd = objfile->obfd;
344 asection *asec = objsec->the_bfd_section;
345 bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd,
347 bfd_vma start = obj_section_addr (objsec) & -align;
348 bfd_vma end = (obj_section_endaddr (objsec) + align - 1) & -align;
349 /* Match if either the entire memory region lies inside the
350 section (i.e. a mapping covering some pages of a large
351 segment) or the entire section lies inside the memory region
352 (i.e. a mapping covering multiple small sections).
354 This BFD was synthesized from reading target memory,
355 we don't want to omit that. */
356 if (((vaddr >= start && vaddr + size <= end)
357 || (start >= vaddr && end <= vaddr + size))
358 && !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY))
361 flags |= SEC_NEVER_LOAD;
362 goto keep; /* break out of two nested for loops */
367 flags |= SEC_READONLY;
375 osec = bfd_make_section_anyway_with_flags (obfd, "load", flags);
378 warning (_("Couldn't make gcore segment: %s"),
379 bfd_errmsg (bfd_get_error ()));
385 fprintf_filtered (gdb_stdout, "Save segment, %s bytes at 0x%s\n",
386 plongest (size), paddr_nz (vaddr));
389 bfd_set_section_size (obfd, osec, size);
390 bfd_set_section_vma (obfd, osec, vaddr);
391 bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */
396 objfile_find_memory_regions (int (*func) (CORE_ADDR, unsigned long,
397 int, int, int, void *),
400 /* Use objfile data to create memory sections. */
401 struct objfile *objfile;
402 struct obj_section *objsec;
403 bfd_vma temp_bottom, temp_top;
405 /* Call callback function for each objfile section. */
406 ALL_OBJSECTIONS (objfile, objsec)
408 bfd *ibfd = objfile->obfd;
409 asection *isec = objsec->the_bfd_section;
410 flagword flags = bfd_get_section_flags (ibfd, isec);
413 if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
415 int size = bfd_section_size (ibfd, isec);
418 ret = (*func) (obj_section_addr (objsec), bfd_section_size (ibfd, isec),
419 1, /* All sections will be readable. */
420 (flags & SEC_READONLY) == 0, /* Writable. */
421 (flags & SEC_CODE) != 0, /* Executable. */
428 /* Make a stack segment. */
429 if (derive_stack_segment (&temp_bottom, &temp_top))
430 (*func) (temp_bottom, temp_top - temp_bottom,
431 1, /* Stack section will be readable. */
432 1, /* Stack section will be writable. */
433 0, /* Stack section will not be executable. */
436 /* Make a heap segment. */
437 if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top))
438 (*func) (temp_bottom, temp_top - temp_bottom,
439 1, /* Heap section will be readable. */
440 1, /* Heap section will be writable. */
441 0, /* Heap section will not be executable. */
448 gcore_copy_callback (bfd *obfd, asection *osec, void *ignored)
450 bfd_size_type size, total_size = bfd_section_size (obfd, osec);
452 struct cleanup *old_chain = NULL;
455 /* Read-only sections are marked; we don't have to copy their contents. */
456 if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0)
459 /* Only interested in "load" sections. */
460 if (strncmp ("load", bfd_section_name (obfd, osec), 4) != 0)
463 size = min (total_size, MAX_COPY_BYTES);
464 memhunk = xmalloc (size);
465 /* ??? This is crap since xmalloc should never return NULL. */
467 error (_("Not enough memory to create corefile."));
468 old_chain = make_cleanup (xfree, memhunk);
470 while (total_size > 0)
472 if (size > total_size)
475 if (target_read_memory (bfd_section_vma (obfd, osec) + offset,
478 warning (_("Memory read failed for corefile section, %s bytes at 0x%s."),
479 plongest (size), paddr (bfd_section_vma (obfd, osec)));
482 if (!bfd_set_section_contents (obfd, osec, memhunk, offset, size))
484 warning (_("Failed to write corefile contents (%s)."),
485 bfd_errmsg (bfd_get_error ()));
493 do_cleanups (old_chain); /* Frees MEMHUNK. */
497 gcore_memory_sections (bfd *obfd)
499 if (target_find_memory_regions (gcore_create_callback, obfd) != 0)
500 return 0; /* FIXME: error return/msg? */
502 /* Record phdrs for section-to-segment mapping. */
503 bfd_map_over_sections (obfd, make_output_phdrs, NULL);
505 /* Copy memory region contents. */
506 bfd_map_over_sections (obfd, gcore_copy_callback, NULL);
512 _initialize_gcore (void)
514 add_com ("generate-core-file", class_files, gcore_command, _("\
515 Save a core file with the current state of the debugged process.\n\
516 Argument is optional filename. Default filename is 'core.<process_id>'."));
518 add_com_alias ("gcore", "generate-core-file", class_files, 1);
519 exec_set_find_memory_regions (objfile_find_memory_regions);