1 /* Generate a core file for the inferior process.
3 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
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 2 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, write to the Free Software
20 Foundation, Inc., 51 Franklin Street, Fifth Floor,
21 Boston, MA 02110-1301, USA. */
31 #include "cli/cli-decode.h"
33 #include "gdb_assert.h"
35 /* The largest amount of memory to read from the target at once. We
36 must throttle it to limit the amount of memory used by GDB during
37 generate-core-file for programs with large resident data. */
38 #define MAX_COPY_BYTES (1024 * 1024)
40 static char *default_gcore_target (void);
41 static enum bfd_architecture default_gcore_arch (void);
42 static unsigned long default_gcore_mach (void);
43 static int gcore_memory_sections (bfd *);
45 /* Generate a core file from the inferior process. */
48 gcore_command (char *args, int from_tty)
50 struct cleanup *old_chain;
51 char *corefilename, corefilename_buffer[40];
52 asection *note_sec = NULL;
54 void *note_data = NULL;
57 /* No use generating a corefile without a target process. */
58 if (!target_has_execution)
65 /* Default corefile name is "core.PID". */
66 sprintf (corefilename_buffer, "core.%d", PIDGET (inferior_ptid));
67 corefilename = corefilename_buffer;
71 fprintf_filtered (gdb_stdout,
72 "Opening corefile '%s' for output.\n", corefilename);
74 /* Open the output file. */
75 obfd = bfd_openw (corefilename, default_gcore_target ());
77 error (_("Failed to open '%s' for output."), corefilename);
79 /* Need a cleanup that will close the file (FIXME: delete it?). */
80 old_chain = make_cleanup_bfd_close (obfd);
82 bfd_set_format (obfd, bfd_core);
83 bfd_set_arch_mach (obfd, default_gcore_arch (), default_gcore_mach ());
85 /* An external target method must build the notes section. */
86 note_data = target_make_corefile_notes (obfd, ¬e_size);
88 /* Create the note section. */
89 if (note_data != NULL && note_size != 0)
91 note_sec = bfd_make_section_anyway_with_flags (obfd, "note0",
96 error (_("Failed to create 'note' section for corefile: %s"),
97 bfd_errmsg (bfd_get_error ()));
99 bfd_set_section_vma (obfd, note_sec, 0);
100 bfd_set_section_alignment (obfd, note_sec, 0);
101 bfd_set_section_size (obfd, note_sec, note_size);
104 /* Now create the memory/load sections. */
105 if (gcore_memory_sections (obfd) == 0)
106 error (_("gcore: failed to get corefile memory sections from target."));
108 /* Write out the contents of the note section. */
109 if (note_data != NULL && note_size != 0)
111 if (!bfd_set_section_contents (obfd, note_sec, note_data, 0, note_size))
112 warning (_("writing note section (%s)"), bfd_errmsg (bfd_get_error ()));
116 fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename);
118 /* Clean-ups will close the output file and free malloc memory. */
119 do_cleanups (old_chain);
124 default_gcore_mach (void)
126 #if 1 /* See if this even matters... */
130 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (current_gdbarch);
133 return bfdarch->mach;
134 if (exec_bfd == NULL)
135 error (_("Can't find default bfd machine type (need execfile)."));
137 return bfd_get_mach (exec_bfd);
141 static enum bfd_architecture
142 default_gcore_arch (void)
144 const struct bfd_arch_info * bfdarch = gdbarch_bfd_arch_info
148 return bfdarch->arch;
149 if (exec_bfd == NULL)
150 error (_("Can't find bfd architecture for corefile (need execfile)."));
152 return bfd_get_arch (exec_bfd);
156 default_gcore_target (void)
158 /* FIXME: This may only work for ELF targets. */
159 if (exec_bfd == NULL)
162 return bfd_get_target (exec_bfd);
165 /* Derive a reasonable stack segment by unwinding the target stack,
166 and store its limits in *BOTTOM and *TOP. Return non-zero if
170 derive_stack_segment (bfd_vma *bottom, bfd_vma *top)
172 struct frame_info *fi, *tmp_fi;
177 /* Can't succeed without stack and registers. */
178 if (!target_has_stack || !target_has_registers)
181 /* Can't succeed without current frame. */
182 fi = get_current_frame ();
186 /* Save frame pointer of TOS frame. */
187 *top = get_frame_base (fi);
188 /* If current stack pointer is more "inner", use that instead. */
189 if (gdbarch_inner_than (current_gdbarch, get_frame_sp (fi), *top))
190 *top = get_frame_sp (fi);
192 /* Find prev-most frame. */
193 while ((tmp_fi = get_prev_frame (fi)) != NULL)
196 /* Save frame pointer of prev-most frame. */
197 *bottom = get_frame_base (fi);
199 /* Now canonicalize their order, so that BOTTOM is a lower address
200 (as opposed to a lower stack frame). */
213 /* Derive a reasonable heap segment for ABFD by looking at sbrk and
214 the static data sections. Store its limits in *BOTTOM and *TOP.
215 Return non-zero if successful. */
218 derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top)
220 bfd_vma top_of_data_memory = 0;
221 bfd_vma top_of_heap = 0;
222 bfd_size_type sec_size;
223 struct value *zero, *sbrk;
230 /* This function depends on being able to call a function in the
232 if (!target_has_execution)
235 /* The following code assumes that the link map is arranged as
236 follows (low to high addresses):
238 ---------------------------------
240 ---------------------------------
241 | data sections (including bss) |
242 ---------------------------------
244 --------------------------------- */
246 for (sec = abfd->sections; sec; sec = sec->next)
248 if (bfd_get_section_flags (abfd, sec) & SEC_DATA
249 || strcmp (".bss", bfd_section_name (abfd, sec)) == 0)
251 sec_vaddr = bfd_get_section_vma (abfd, sec);
252 sec_size = bfd_get_section_size (sec);
253 if (sec_vaddr + sec_size > top_of_data_memory)
254 top_of_data_memory = sec_vaddr + sec_size;
258 /* Now get the top-of-heap by calling sbrk in the inferior. */
259 if (lookup_minimal_symbol ("sbrk", NULL, NULL) != NULL)
261 sbrk = find_function_in_inferior ("sbrk");
265 else if (lookup_minimal_symbol ("_sbrk", NULL, NULL) != NULL)
267 sbrk = find_function_in_inferior ("_sbrk");
274 zero = value_from_longest (builtin_type_int, 0);
276 sbrk = call_function_by_hand (sbrk, 1, &zero);
279 top_of_heap = value_as_long (sbrk);
281 /* Return results. */
282 if (top_of_heap > top_of_data_memory)
284 *bottom = top_of_data_memory;
289 /* No additional heap space needs to be saved. */
294 make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
299 /* FIXME: these constants may only be applicable for ELF. */
300 if (strncmp (bfd_section_name (obfd, osec), "load", 4) == 0)
305 p_flags |= PF_R; /* Segment is readable. */
306 if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY))
307 p_flags |= PF_W; /* Segment is writable. */
308 if (bfd_get_section_flags (obfd, osec) & SEC_CODE)
309 p_flags |= PF_X; /* Segment is executable. */
311 bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec);
315 gcore_create_callback (CORE_ADDR vaddr, unsigned long size,
316 int read, int write, int exec, void *data)
320 flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD;
322 /* If the memory segment has no permissions set, ignore it, otherwise
323 when we later try to access it for read/write, we'll get an error
324 or jam the kernel. */
325 if (read == 0 && write == 0 && exec == 0)
329 fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at 0x%s\n",
330 paddr_d (size), paddr_nz (vaddr));
338 /* See if this region of memory lies inside a known file on disk.
339 If so, we can avoid copying its contents by clearing SEC_LOAD. */
340 struct objfile *objfile;
341 struct obj_section *objsec;
343 ALL_OBJSECTIONS (objfile, objsec)
345 bfd *abfd = objfile->obfd;
346 asection *asec = objsec->the_bfd_section;
347 bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd,
349 bfd_vma start = objsec->addr & -align;
350 bfd_vma end = (objsec->endaddr + align - 1) & -align;
351 /* Match if either the entire memory region lies inside the
352 section (i.e. a mapping covering some pages of a large
353 segment) or the entire section lies inside the memory region
354 (i.e. a mapping covering multiple small sections).
356 This BFD was synthesized from reading target memory,
357 we don't want to omit that. */
358 if (((vaddr >= start && vaddr + size <= end)
359 || (start >= vaddr && end <= vaddr + size))
360 && !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY))
363 flags |= SEC_NEVER_LOAD;
364 goto keep; /* break out of two nested for loops */
369 flags |= SEC_READONLY;
377 osec = bfd_make_section_anyway_with_flags (obfd, "load", flags);
380 warning (_("Couldn't make gcore segment: %s"),
381 bfd_errmsg (bfd_get_error ()));
387 fprintf_filtered (gdb_stdout, "Save segment, %s bytes at 0x%s\n",
388 paddr_d (size), paddr_nz (vaddr));
391 bfd_set_section_size (obfd, osec, size);
392 bfd_set_section_vma (obfd, osec, vaddr);
393 bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */
398 objfile_find_memory_regions (int (*func) (CORE_ADDR, unsigned long,
399 int, int, int, void *),
402 /* Use objfile data to create memory sections. */
403 struct objfile *objfile;
404 struct obj_section *objsec;
405 bfd_vma temp_bottom, temp_top;
407 /* Call callback function for each objfile section. */
408 ALL_OBJSECTIONS (objfile, objsec)
410 bfd *ibfd = objfile->obfd;
411 asection *isec = objsec->the_bfd_section;
412 flagword flags = bfd_get_section_flags (ibfd, isec);
415 if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
417 int size = bfd_section_size (ibfd, isec);
420 ret = (*func) (objsec->addr, bfd_section_size (ibfd, isec),
421 1, /* All sections will be readable. */
422 (flags & SEC_READONLY) == 0, /* Writable. */
423 (flags & SEC_CODE) != 0, /* Executable. */
430 /* Make a stack segment. */
431 if (derive_stack_segment (&temp_bottom, &temp_top))
432 (*func) (temp_bottom, temp_top - temp_bottom,
433 1, /* Stack section will be readable. */
434 1, /* Stack section will be writable. */
435 0, /* Stack section will not be executable. */
438 /* Make a heap segment. */
439 if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top))
440 (*func) (temp_bottom, temp_top - temp_bottom,
441 1, /* Heap section will be readable. */
442 1, /* Heap section will be writable. */
443 0, /* Heap section will not be executable. */
450 gcore_copy_callback (bfd *obfd, asection *osec, void *ignored)
452 bfd_size_type size, total_size = bfd_section_size (obfd, osec);
454 struct cleanup *old_chain = NULL;
457 /* Read-only sections are marked; we don't have to copy their contents. */
458 if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0)
461 /* Only interested in "load" sections. */
462 if (strncmp ("load", bfd_section_name (obfd, osec), 4) != 0)
465 size = min (total_size, MAX_COPY_BYTES);
466 memhunk = xmalloc (size);
467 /* ??? This is crap since xmalloc should never return NULL. */
469 error (_("Not enough memory to create corefile."));
470 old_chain = make_cleanup (xfree, memhunk);
472 while (total_size > 0)
474 if (size > total_size)
477 if (target_read_memory (bfd_section_vma (obfd, osec) + offset,
480 warning (_("Memory read failed for corefile section, %s bytes at 0x%s."),
481 paddr_d (size), paddr (bfd_section_vma (obfd, osec)));
484 if (!bfd_set_section_contents (obfd, osec, memhunk, offset, size))
486 warning (_("Failed to write corefile contents (%s)."),
487 bfd_errmsg (bfd_get_error ()));
495 do_cleanups (old_chain); /* Frees MEMHUNK. */
499 gcore_memory_sections (bfd *obfd)
501 if (target_find_memory_regions (gcore_create_callback, obfd) != 0)
502 return 0; /* FIXME: error return/msg? */
504 /* Record phdrs for section-to-segment mapping. */
505 bfd_map_over_sections (obfd, make_output_phdrs, NULL);
507 /* Copy memory region contents. */
508 bfd_map_over_sections (obfd, gcore_copy_callback, NULL);
514 _initialize_gcore (void)
516 add_com ("generate-core-file", class_files, gcore_command, _("\
517 Save a core file with the current state of the debugged process.\n\
518 Argument is optional filename. Default filename is 'core.<process_id>'."));
520 add_com_alias ("gcore", "generate-core-file", class_files, 1);
521 exec_set_find_memory_regions (objfile_find_memory_regions);