1 /* Generate a core file for the inferior process.
3 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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/>. */
28 #include "arch-utils.h"
29 #include "completer.h"
31 #include "cli/cli-decode.h"
32 #include "gdb_assert.h"
37 /* The largest amount of memory to read from the target at once. We
38 must throttle it to limit the amount of memory used by GDB during
39 generate-core-file for programs with large resident data. */
40 #define MAX_COPY_BYTES (1024 * 1024)
42 static const char *default_gcore_target (void);
43 static enum bfd_architecture default_gcore_arch (void);
44 static unsigned long default_gcore_mach (void);
45 static int gcore_memory_sections (bfd *);
47 /* create_gcore_bfd -- helper for gcore_command (exported).
48 Open a new bfd core file for output, and return the handle. */
51 create_gcore_bfd (char *filename)
53 bfd *obfd = bfd_openw (filename, default_gcore_target ());
55 error (_("Failed to open '%s' for output."), filename);
56 bfd_set_format (obfd, bfd_core);
57 bfd_set_arch_mach (obfd, default_gcore_arch (), default_gcore_mach ());
61 /* write_gcore_file -- helper for gcore_command (exported).
62 Compose and write the corefile data to the core file. */
66 write_gcore_file (bfd *obfd)
68 void *note_data = NULL;
70 asection *note_sec = NULL;
72 /* An external target method must build the notes section. */
73 note_data = target_make_corefile_notes (obfd, ¬e_size);
75 /* Create the note section. */
76 if (note_data != NULL && note_size != 0)
78 note_sec = bfd_make_section_anyway_with_flags (obfd, "note0",
83 error (_("Failed to create 'note' section for corefile: %s"),
84 bfd_errmsg (bfd_get_error ()));
86 bfd_set_section_vma (obfd, note_sec, 0);
87 bfd_set_section_alignment (obfd, note_sec, 0);
88 bfd_set_section_size (obfd, note_sec, note_size);
91 /* Now create the memory/load sections. */
92 if (gcore_memory_sections (obfd) == 0)
93 error (_("gcore: failed to get corefile memory sections from target."));
95 /* Write out the contents of the note section. */
96 if (note_data != NULL && note_size != 0)
98 if (!bfd_set_section_contents (obfd, note_sec, note_data, 0, note_size))
99 warning (_("writing note section (%s)"),
100 bfd_errmsg (bfd_get_error ()));
104 /* gcore_command -- implements the 'gcore' command.
105 Generate a core file from the inferior process. */
108 gcore_command (char *args, int from_tty)
110 struct cleanup *old_chain;
111 char *corefilename, corefilename_buffer[40];
114 /* No use generating a corefile without a target process. */
115 if (!target_has_execution)
122 /* Default corefile name is "core.PID". */
123 sprintf (corefilename_buffer, "core.%d", PIDGET (inferior_ptid));
124 corefilename = corefilename_buffer;
128 fprintf_filtered (gdb_stdout,
129 "Opening corefile '%s' for output.\n", corefilename);
131 /* Open the output file. */
132 obfd = create_gcore_bfd (corefilename);
134 /* Need a cleanup that will close the file (FIXME: delete it?). */
135 old_chain = make_cleanup_bfd_close (obfd);
137 /* Call worker function. */
138 write_gcore_file (obfd);
141 fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename);
143 /* Clean-ups will close the output file and free malloc memory. */
144 do_cleanups (old_chain);
149 default_gcore_mach (void)
151 #if 1 /* See if this even matters... */
155 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch);
158 return bfdarch->mach;
159 if (exec_bfd == NULL)
160 error (_("Can't find default bfd machine type (need execfile)."));
162 return bfd_get_mach (exec_bfd);
166 static enum bfd_architecture
167 default_gcore_arch (void)
169 const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch);
172 return bfdarch->arch;
173 if (exec_bfd == NULL)
174 error (_("Can't find bfd architecture for corefile (need execfile)."));
176 return bfd_get_arch (exec_bfd);
180 default_gcore_target (void)
182 /* The gdbarch may define a target to use for core files. */
183 if (gdbarch_gcore_bfd_target_p (target_gdbarch))
184 return gdbarch_gcore_bfd_target (target_gdbarch);
186 /* Otherwise, try to fall back to the exec_bfd target. This will probably
187 not work for non-ELF targets. */
188 if (exec_bfd == NULL)
191 return bfd_get_target (exec_bfd);
194 /* Derive a reasonable stack segment by unwinding the target stack,
195 and store its limits in *BOTTOM and *TOP. Return non-zero if
199 derive_stack_segment (bfd_vma *bottom, bfd_vma *top)
201 struct frame_info *fi, *tmp_fi;
206 /* Can't succeed without stack and registers. */
207 if (!target_has_stack || !target_has_registers)
210 /* Can't succeed without current frame. */
211 fi = get_current_frame ();
215 /* Save frame pointer of TOS frame. */
216 *top = get_frame_base (fi);
217 /* If current stack pointer is more "inner", use that instead. */
218 if (gdbarch_inner_than (get_frame_arch (fi), get_frame_sp (fi), *top))
219 *top = get_frame_sp (fi);
221 /* Find prev-most frame. */
222 while ((tmp_fi = get_prev_frame (fi)) != NULL)
225 /* Save frame pointer of prev-most frame. */
226 *bottom = get_frame_base (fi);
228 /* Now canonicalize their order, so that BOTTOM is a lower address
229 (as opposed to a lower stack frame). */
242 /* call_target_sbrk --
243 helper function for derive_heap_segment. */
246 call_target_sbrk (int sbrk_arg)
248 struct objfile *sbrk_objf;
249 struct gdbarch *gdbarch;
251 struct value *target_sbrk_arg;
252 struct value *sbrk_fn, *ret;
255 if (lookup_minimal_symbol ("sbrk", NULL, NULL) != NULL)
257 sbrk_fn = find_function_in_inferior ("sbrk", &sbrk_objf);
261 else if (lookup_minimal_symbol ("_sbrk", NULL, NULL) != NULL)
263 sbrk_fn = find_function_in_inferior ("_sbrk", &sbrk_objf);
270 gdbarch = get_objfile_arch (sbrk_objf);
271 target_sbrk_arg = value_from_longest (builtin_type (gdbarch)->builtin_int,
273 gdb_assert (target_sbrk_arg);
274 ret = call_function_by_hand (sbrk_fn, 1, &target_sbrk_arg);
278 tmp = value_as_long (ret);
279 if ((LONGEST) tmp <= 0 || (LONGEST) tmp == 0xffffffff)
286 /* Derive a reasonable heap segment for ABFD by looking at sbrk and
287 the static data sections. Store its limits in *BOTTOM and *TOP.
288 Return non-zero if successful. */
291 derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top)
293 struct gdbarch *gdbarch;
294 bfd_vma top_of_data_memory = 0;
295 bfd_vma top_of_heap = 0;
296 bfd_size_type sec_size;
303 /* This function depends on being able to call a function in the
305 if (!target_has_execution)
308 /* The following code assumes that the link map is arranged as
309 follows (low to high addresses):
311 ---------------------------------
313 ---------------------------------
314 | data sections (including bss) |
315 ---------------------------------
317 --------------------------------- */
319 for (sec = abfd->sections; sec; sec = sec->next)
321 if (bfd_get_section_flags (abfd, sec) & SEC_DATA
322 || strcmp (".bss", bfd_section_name (abfd, sec)) == 0)
324 sec_vaddr = bfd_get_section_vma (abfd, sec);
325 sec_size = bfd_get_section_size (sec);
326 if (sec_vaddr + sec_size > top_of_data_memory)
327 top_of_data_memory = sec_vaddr + sec_size;
331 top_of_heap = call_target_sbrk (0);
332 if (top_of_heap == (bfd_vma) 0)
335 /* Return results. */
336 if (top_of_heap > top_of_data_memory)
338 *bottom = top_of_data_memory;
343 /* No additional heap space needs to be saved. */
348 make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
353 /* FIXME: these constants may only be applicable for ELF. */
354 if (strncmp (bfd_section_name (obfd, osec), "load", 4) == 0)
356 else if (strncmp (bfd_section_name (obfd, osec), "note", 4) == 0)
361 p_flags |= PF_R; /* Segment is readable. */
362 if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY))
363 p_flags |= PF_W; /* Segment is writable. */
364 if (bfd_get_section_flags (obfd, osec) & SEC_CODE)
365 p_flags |= PF_X; /* Segment is executable. */
367 bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec);
371 gcore_create_callback (CORE_ADDR vaddr, unsigned long size,
372 int read, int write, int exec, void *data)
376 flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD;
378 /* If the memory segment has no permissions set, ignore it, otherwise
379 when we later try to access it for read/write, we'll get an error
380 or jam the kernel. */
381 if (read == 0 && write == 0 && exec == 0)
385 fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at %s\n",
386 plongest (size), paddress (target_gdbarch, vaddr));
394 /* See if this region of memory lies inside a known file on disk.
395 If so, we can avoid copying its contents by clearing SEC_LOAD. */
396 struct objfile *objfile;
397 struct obj_section *objsec;
399 ALL_OBJSECTIONS (objfile, objsec)
401 bfd *abfd = objfile->obfd;
402 asection *asec = objsec->the_bfd_section;
403 bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd,
405 bfd_vma start = obj_section_addr (objsec) & -align;
406 bfd_vma end = (obj_section_endaddr (objsec) + align - 1) & -align;
407 /* Match if either the entire memory region lies inside the
408 section (i.e. a mapping covering some pages of a large
409 segment) or the entire section lies inside the memory region
410 (i.e. a mapping covering multiple small sections).
412 This BFD was synthesized from reading target memory,
413 we don't want to omit that. */
414 if (((vaddr >= start && vaddr + size <= end)
415 || (start >= vaddr && end <= vaddr + size))
416 && !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY))
419 flags |= SEC_NEVER_LOAD;
420 goto keep; /* break out of two nested for loops */
425 flags |= SEC_READONLY;
433 osec = bfd_make_section_anyway_with_flags (obfd, "load", flags);
436 warning (_("Couldn't make gcore segment: %s"),
437 bfd_errmsg (bfd_get_error ()));
443 fprintf_filtered (gdb_stdout, "Save segment, %s bytes at %s\n",
444 plongest (size), paddress (target_gdbarch, vaddr));
447 bfd_set_section_size (obfd, osec, size);
448 bfd_set_section_vma (obfd, osec, vaddr);
449 bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */
454 objfile_find_memory_regions (int (*func) (CORE_ADDR, unsigned long,
455 int, int, int, void *),
458 /* Use objfile data to create memory sections. */
459 struct objfile *objfile;
460 struct obj_section *objsec;
461 bfd_vma temp_bottom, temp_top;
463 /* Call callback function for each objfile section. */
464 ALL_OBJSECTIONS (objfile, objsec)
466 bfd *ibfd = objfile->obfd;
467 asection *isec = objsec->the_bfd_section;
468 flagword flags = bfd_get_section_flags (ibfd, isec);
471 if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
473 int size = bfd_section_size (ibfd, isec);
476 ret = (*func) (obj_section_addr (objsec), bfd_section_size (ibfd, isec),
477 1, /* All sections will be readable. */
478 (flags & SEC_READONLY) == 0, /* Writable. */
479 (flags & SEC_CODE) != 0, /* Executable. */
486 /* Make a stack segment. */
487 if (derive_stack_segment (&temp_bottom, &temp_top))
488 (*func) (temp_bottom, temp_top - temp_bottom,
489 1, /* Stack section will be readable. */
490 1, /* Stack section will be writable. */
491 0, /* Stack section will not be executable. */
494 /* Make a heap segment. */
495 if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top))
496 (*func) (temp_bottom, temp_top - temp_bottom,
497 1, /* Heap section will be readable. */
498 1, /* Heap section will be writable. */
499 0, /* Heap section will not be executable. */
506 gcore_copy_callback (bfd *obfd, asection *osec, void *ignored)
508 bfd_size_type size, total_size = bfd_section_size (obfd, osec);
510 struct cleanup *old_chain = NULL;
513 /* Read-only sections are marked; we don't have to copy their contents. */
514 if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0)
517 /* Only interested in "load" sections. */
518 if (strncmp ("load", bfd_section_name (obfd, osec), 4) != 0)
521 size = min (total_size, MAX_COPY_BYTES);
522 memhunk = xmalloc (size);
523 /* ??? This is crap since xmalloc should never return NULL. */
525 error (_("Not enough memory to create corefile."));
526 old_chain = make_cleanup (xfree, memhunk);
528 while (total_size > 0)
530 if (size > total_size)
533 if (target_read_memory (bfd_section_vma (obfd, osec) + offset,
536 warning (_("Memory read failed for corefile section, %s bytes at %s."),
538 paddress (target_gdbarch, bfd_section_vma (obfd, osec)));
541 if (!bfd_set_section_contents (obfd, osec, memhunk, offset, size))
543 warning (_("Failed to write corefile contents (%s)."),
544 bfd_errmsg (bfd_get_error ()));
552 do_cleanups (old_chain); /* Frees MEMHUNK. */
556 gcore_memory_sections (bfd *obfd)
558 if (target_find_memory_regions (gcore_create_callback, obfd) != 0)
559 return 0; /* FIXME: error return/msg? */
561 /* Record phdrs for section-to-segment mapping. */
562 bfd_map_over_sections (obfd, make_output_phdrs, NULL);
564 /* Copy memory region contents. */
565 bfd_map_over_sections (obfd, gcore_copy_callback, NULL);
570 /* Provide a prototype to silence -Wmissing-prototypes. */
571 extern initialize_file_ftype _initialize_gcore;
574 _initialize_gcore (void)
576 add_com ("generate-core-file", class_files, gcore_command, _("\
577 Save a core file with the current state of the debugged process.\n\
578 Argument is optional filename. Default filename is 'core.<process_id>'."));
580 add_com_alias ("gcore", "generate-core-file", class_files, 1);
581 exec_set_find_memory_regions (objfile_find_memory_regions);