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binutils-gdb/gdb/gcore.c
Pedro Alves 7022349d5c Stop assuming no-debug-info functions return int 
The fact that GDB defaults to assuming that functions return int, when
it has no debug info for the function has been a recurring source of
user confusion.  Recently this came up on the errno pretty printer
discussions.  Shortly after, it came up again on IRC, with someone
wondering why does getenv() in GDB return a negative int:

  (gdb) p getenv("PATH")
  $1 = -6185

This question (with s/getenv/random-other-C-runtime-function) is a FAQ
on IRC.

The reason for the above is:

 (gdb) p getenv
 $2 = {<text variable, no debug info>} 0x7ffff7751d80 <getenv>
 (gdb) ptype getenv
 type = int ()

... which means that GDB truncated the 64-bit pointer that is actually
returned from getent to 32-bit, and then sign-extended it:

 (gdb) p /x -6185
 $6 = 0xffffe7d7

The workaround is to cast the function to the right type, like:

 (gdb) p ((char *(*) (const char *)) getenv) ("PATH")
 $3 = 0x7fffffffe7d7 "/usr/local/bin:/"...

IMO, we should do better than this.

I see the "assume-int" issue the same way I see printing bogus values
for optimized-out variables instead of "<optimized out>" -- I'd much
rather that the debugger tells me "I don't know" and tells me how to
fix it than showing me bogus misleading results, making me go around
tilting at windmills.

If GDB prints a signed integer when you're expecting a pointer or
aggregate, you at least have some sense that something is off, but
consider the case of the function actually returning a 64-bit integer.
For example, compile this without debug info:

 unsigned long long
 function ()
 {
   return 0x7fffffffffffffff;
 }

Currently, with pristine GDB, you get:

 (gdb) p function ()
 $1 = -1                      # incorrect
 (gdb) p /x function ()
 $2 = 0xffffffff              # incorrect

maybe after spending a few hours debugging you suspect something is
wrong with that -1, and do:

 (gdb) ptype function
 type = int ()

and maybe, just maybe, you realize that the function actually returns
unsigned long long.  And you try to fix it with:

(gdb) p /x (unsigned long long) function ()
 $3 = 0xffffffffffffffff      # incorrect

... which still produces the wrong result, because GDB simply applied
int to unsigned long long conversion.  Meaning, it sign-extended the
integer that it extracted from the return of the function, to 64-bits.

and then maybe, after asking around on IRC, you realize you have to
cast the function to a pointer of the right type, and call that.  It
won't be easy, but after a few missteps, you'll get to it:

.....  (gdb) p /x ((unsigned long long(*) ()) function) ()
 $666 = 0x7fffffffffffffff             # finally! :-)


So to improve on the user experience, this patch does the following
(interrelated) things:

 - makes no-debug-info functions no longer default to "int" as return
   type.  Instead, they're left with NULL/"<unknown return type>"
   return type.

    (gdb) ptype getenv
    type = <unknown return type> ()

 - makes calling a function with unknown return type an error.

    (gdb) p getenv ("PATH")
    'getenv' has unknown return type; cast the call to its declared return type

 - and then to make it easier to call the function, makes it possible
   to _only_ cast the return of the function to the right type,
   instead of having to cast the function to a function pointer:

    (gdb) p (char *) getenv ("PATH")                      # now Just Works
    $3 = 0x7fffffffe7d7 "/usr/local/bin:/"...

    (gdb) p ((char *(*) (const char *)) getenv) ("PATH")  # continues working
    $4 = 0x7fffffffe7d7 "/usr/local/bin:/"...

   I.e., it makes GDB default the function's return type to the type
   of the cast, and the function's parameters to the type of the
   arguments passed down.

After this patch, here's what you'll get for the "unsigned long long"
example above:

 (gdb) p function ()
 'function' has unknown return type; cast the call to its declared return type
 (gdb) p /x (unsigned long long) function ()
 $4 = 0x7fffffffffffffff     # correct!

Note that while with "print" GDB shows the name of the function that
has the problem:

  (gdb) p getenv ("PATH")
  'getenv' has unknown return type; cast the call to its declared return type

which can by handy in more complicated expressions, "ptype" does not:

  (gdb) ptype getenv ("PATH")
  function has unknown return type; cast the call to its declared return type

This will be fixed in the next patch.

gdb/ChangeLog:
2017-09-04  Pedro Alves  <palves@redhat.com>

	* ada-lang.c (ada_evaluate_subexp) <TYPE_CODE_FUNC>: Don't handle
	TYPE_GNU_IFUNC specially here.  Throw error if return type is
	unknown.
	* ada-typeprint.c (print_func_type): Handle functions with unknown
	return type.
	* c-typeprint.c (c_type_print_base): Handle functions and methods
	with unknown return type.
	* compile/compile-c-symbols.c (convert_symbol_bmsym)
	<mst_text_gnu_ifunc>: Use nodebug_text_gnu_ifunc_symbol.
	* compile/compile-c-types.c: Include "objfiles.h".
	(convert_func): For functions with unknown return type, warn and
	default to int.
	* compile/compile-object-run.c (compile_object_run): Adjust call
	to call_function_by_hand_dummy.
	* elfread.c (elf_gnu_ifunc_resolve_addr): Adjust call to
	call_function_by_hand.
	* eval.c (evaluate_subexp_standard): Adjust calls to
	call_function_by_hand.  Handle functions and methods with unknown
	return type.  Pass expect_type to call_function_by_hand.
	* f-typeprint.c (f_type_print_base): Handle functions with unknown
	return type.
	* gcore.c (call_target_sbrk): Adjust call to
	call_function_by_hand.
	* gdbtypes.c (objfile_type): Leave nodebug text symbol with NULL
	return type instead of int.  Make nodebug_text_gnu_ifunc_symbol be
	an integer address type instead of nodebug.
	* guile/scm-value.c (gdbscm_value_call): Adjust call to
	call_function_by_hand.
	* infcall.c (error_call_unknown_return_type): New function.
	(call_function_by_hand): New "default_return_type" parameter.
	Pass it down.
	(call_function_by_hand_dummy): New "default_return_type"
	parameter.  Use it instead of defaulting to int.  If there's no
	default and the return type is unknown, throw an error.  If
	there's a default return type, and the called function has no
	debug info, then assume the function is prototyped.
	* infcall.h (call_function_by_hand, call_function_by_hand_dummy):
	New "default_return_type" parameter.
	(error_call_unknown_return_type): New declaration.
	* linux-fork.c (call_lseek): Cast return type of lseek.
	(inferior_call_waitpid, checkpoint_command): Adjust calls to
	call_function_by_hand.
	* linux-tdep.c (linux_infcall_mmap, linux_infcall_munmap): Adjust
	calls to call_function_by_hand.
	* m2-typeprint.c (m2_procedure): Handle functions with unknown
	return type.
	* objc-lang.c (lookup_objc_class, lookup_child_selector)
	(value_nsstring, print_object_command): Adjust calls to
	call_function_by_hand.
	* p-typeprint.c (pascal_type_print_varspec_prefix): Handle
	functions with unknown return type.
	(pascal_type_print_func_varspec_suffix): New function.
	(pascal_type_print_varspec_suffix) <TYPE_CODE_FUNC,
	TYPE_CODE_METHOD>: Use it.
	* python/py-value.c (valpy_call): Adjust call to
	call_function_by_hand.
	* rust-lang.c (rust_evaluate_funcall): Adjust call to
	call_function_by_hand.
	* valarith.c (value_x_binop, value_x_unop): Adjust calls to
	call_function_by_hand.
	* valops.c (value_allocate_space_in_inferior): Adjust call to
	call_function_by_hand.
	* typeprint.c (type_print_unknown_return_type): New function.
	* typeprint.h (type_print_unknown_return_type): New declaration.

gdb/testsuite/ChangeLog:
2017-09-04  Pedro Alves  <palves@redhat.com>

	* gdb.base/break-main-file-remove-fail.exp (test_remove_bp): Cast
	return type of munmap in infcall.
	* gdb.base/break-probes.exp: Cast return type of foo in infcall.
	* gdb.base/checkpoint.exp: Simplify using for loop.  Cast return
	type of ftell in infcall.
	* gdb.base/dprintf-detach.exp (dprintf_detach_test): Cast return
	type of getpid in infcall.
	* gdb.base/infcall-exec.exp: Cast return type of execlp in
	infcall.
	* gdb.base/info-os.exp: Cast return type of getpid in infcall.
	Bail on failure to extract the pid.
	* gdb.base/nodebug.c: #include <stdint.h>.
	(multf, multf_noproto, mult, mult_noproto, add8, add8_noproto):
	New functions.
	* gdb.base/nodebug.exp (test_call_promotion): New procedure.
	Change expected output of print/whatis/ptype with functions with
	no debug info.  Test all supported languages.  Call
	test_call_promotion.
	* gdb.compile/compile.exp: Adjust expected output to expect
	warning.
	* gdb.threads/siginfo-threads.exp: Likewise.
2017-09-04 20:21:13 +01:00

624 lines
18 KiB
C
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/* Generate a core file for the inferior process.
Copyright (C) 2001-2017 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "elf-bfd.h"
#include "infcall.h"
#include "inferior.h"
#include "gdbcore.h"
#include "objfiles.h"
#include "solib.h"
#include "symfile.h"
#include "arch-utils.h"
#include "completer.h"
#include "gcore.h"
#include "cli/cli-decode.h"
#include <fcntl.h>
#include "regcache.h"
#include "regset.h"
#include "gdb_bfd.h"
#include "readline/tilde.h"
#include <algorithm>
#include "common/gdb_unlinker.h"
#include "byte-vector.h"
/* The largest amount of memory to read from the target at once. We
must throttle it to limit the amount of memory used by GDB during
generate-core-file for programs with large resident data. */
#define MAX_COPY_BYTES (1024 * 1024)
static const char *default_gcore_target (void);
static enum bfd_architecture default_gcore_arch (void);
static unsigned long default_gcore_mach (void);
static int gcore_memory_sections (bfd *);
/* create_gcore_bfd -- helper for gcore_command (exported).
Open a new bfd core file for output, and return the handle. */
gdb_bfd_ref_ptr
create_gcore_bfd (const char *filename)
{
gdb_bfd_ref_ptr obfd (gdb_bfd_openw (filename, default_gcore_target ()));
if (obfd == NULL)
error (_("Failed to open '%s' for output."), filename);
bfd_set_format (obfd.get (), bfd_core);
bfd_set_arch_mach (obfd.get (), default_gcore_arch (), default_gcore_mach ());
return obfd;
}
/* write_gcore_file_1 -- do the actual work of write_gcore_file. */
static void
write_gcore_file_1 (bfd *obfd)
{
struct cleanup *cleanup;
void *note_data = NULL;
int note_size = 0;
asection *note_sec = NULL;
/* An external target method must build the notes section. */
/* FIXME: uweigand/2011-10-06: All architectures that support core file
generation should be converted to gdbarch_make_corefile_notes; at that
point, the target vector method can be removed. */
if (!gdbarch_make_corefile_notes_p (target_gdbarch ()))
note_data = target_make_corefile_notes (obfd, &note_size);
else
note_data = gdbarch_make_corefile_notes (target_gdbarch (), obfd, &note_size);
cleanup = make_cleanup (xfree, note_data);
if (note_data == NULL || note_size == 0)
error (_("Target does not support core file generation."));
/* Create the note section. */
note_sec = bfd_make_section_anyway_with_flags (obfd, "note0",
SEC_HAS_CONTENTS
| SEC_READONLY
| SEC_ALLOC);
if (note_sec == NULL)
error (_("Failed to create 'note' section for corefile: %s"),
bfd_errmsg (bfd_get_error ()));
bfd_set_section_vma (obfd, note_sec, 0);
bfd_set_section_alignment (obfd, note_sec, 0);
bfd_set_section_size (obfd, note_sec, note_size);
/* Now create the memory/load sections. */
if (gcore_memory_sections (obfd) == 0)
error (_("gcore: failed to get corefile memory sections from target."));
/* Write out the contents of the note section. */
if (!bfd_set_section_contents (obfd, note_sec, note_data, 0, note_size))
warning (_("writing note section (%s)"), bfd_errmsg (bfd_get_error ()));
do_cleanups (cleanup);
}
/* write_gcore_file -- helper for gcore_command (exported).
Compose and write the corefile data to the core file. */
void
write_gcore_file (bfd *obfd)
{
struct gdb_exception except = exception_none;
target_prepare_to_generate_core ();
TRY
{
write_gcore_file_1 (obfd);
}
CATCH (e, RETURN_MASK_ALL)
{
except = e;
}
END_CATCH
target_done_generating_core ();
if (except.reason < 0)
throw_exception (except);
}
/* gcore_command -- implements the 'gcore' command.
Generate a core file from the inferior process. */
static void
gcore_command (char *args, int from_tty)
{
gdb::unique_xmalloc_ptr<char> corefilename;
/* No use generating a corefile without a target process. */
if (!target_has_execution)
noprocess ();
if (args && *args)
corefilename.reset (tilde_expand (args));
else
{
/* Default corefile name is "core.PID". */
corefilename.reset (xstrprintf ("core.%d", ptid_get_pid (inferior_ptid)));
}
if (info_verbose)
fprintf_filtered (gdb_stdout,
"Opening corefile '%s' for output.\n",
corefilename.get ());
/* Open the output file. */
gdb_bfd_ref_ptr obfd (create_gcore_bfd (corefilename.get ()));
/* Arrange to unlink the file on failure. */
gdb::unlinker unlink_file (corefilename.get ());
/* Call worker function. */
write_gcore_file (obfd.get ());
/* Succeeded. */
unlink_file.keep ();
fprintf_filtered (gdb_stdout, "Saved corefile %s\n", corefilename.get ());
}
static unsigned long
default_gcore_mach (void)
{
#if 1 /* See if this even matters... */
return 0;
#else
const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
if (bfdarch != NULL)
return bfdarch->mach;
if (exec_bfd == NULL)
error (_("Can't find default bfd machine type (need execfile)."));
return bfd_get_mach (exec_bfd);
#endif /* 1 */
}
static enum bfd_architecture
default_gcore_arch (void)
{
const struct bfd_arch_info *bfdarch = gdbarch_bfd_arch_info (target_gdbarch ());
if (bfdarch != NULL)
return bfdarch->arch;
if (exec_bfd == NULL)
error (_("Can't find bfd architecture for corefile (need execfile)."));
return bfd_get_arch (exec_bfd);
}
static const char *
default_gcore_target (void)
{
/* The gdbarch may define a target to use for core files. */
if (gdbarch_gcore_bfd_target_p (target_gdbarch ()))
return gdbarch_gcore_bfd_target (target_gdbarch ());
/* Otherwise, try to fall back to the exec_bfd target. This will probably
not work for non-ELF targets. */
if (exec_bfd == NULL)
return NULL;
else
return bfd_get_target (exec_bfd);
}
/* Derive a reasonable stack segment by unwinding the target stack,
and store its limits in *BOTTOM and *TOP. Return non-zero if
successful. */
static int
derive_stack_segment (bfd_vma *bottom, bfd_vma *top)
{
struct frame_info *fi, *tmp_fi;
gdb_assert (bottom);
gdb_assert (top);
/* Can't succeed without stack and registers. */
if (!target_has_stack || !target_has_registers)
return 0;
/* Can't succeed without current frame. */
fi = get_current_frame ();
if (fi == NULL)
return 0;
/* Save frame pointer of TOS frame. */
*top = get_frame_base (fi);
/* If current stack pointer is more "inner", use that instead. */
if (gdbarch_inner_than (get_frame_arch (fi), get_frame_sp (fi), *top))
*top = get_frame_sp (fi);
/* Find prev-most frame. */
while ((tmp_fi = get_prev_frame (fi)) != NULL)
fi = tmp_fi;
/* Save frame pointer of prev-most frame. */
*bottom = get_frame_base (fi);
/* Now canonicalize their order, so that BOTTOM is a lower address
(as opposed to a lower stack frame). */
if (*bottom > *top)
{
bfd_vma tmp_vma;
tmp_vma = *top;
*top = *bottom;
*bottom = tmp_vma;
}
return 1;
}
/* call_target_sbrk --
helper function for derive_heap_segment. */
static bfd_vma
call_target_sbrk (int sbrk_arg)
{
struct objfile *sbrk_objf;
struct gdbarch *gdbarch;
bfd_vma top_of_heap;
struct value *target_sbrk_arg;
struct value *sbrk_fn, *ret;
bfd_vma tmp;
if (lookup_minimal_symbol ("sbrk", NULL, NULL).minsym != NULL)
{
sbrk_fn = find_function_in_inferior ("sbrk", &sbrk_objf);
if (sbrk_fn == NULL)
return (bfd_vma) 0;
}
else if (lookup_minimal_symbol ("_sbrk", NULL, NULL).minsym != NULL)
{
sbrk_fn = find_function_in_inferior ("_sbrk", &sbrk_objf);
if (sbrk_fn == NULL)
return (bfd_vma) 0;
}
else
return (bfd_vma) 0;
gdbarch = get_objfile_arch (sbrk_objf);
target_sbrk_arg = value_from_longest (builtin_type (gdbarch)->builtin_int,
sbrk_arg);
gdb_assert (target_sbrk_arg);
ret = call_function_by_hand (sbrk_fn, NULL, 1, &target_sbrk_arg);
if (ret == NULL)
return (bfd_vma) 0;
tmp = value_as_long (ret);
if ((LONGEST) tmp <= 0 || (LONGEST) tmp == 0xffffffff)
return (bfd_vma) 0;
top_of_heap = tmp;
return top_of_heap;
}
/* Derive a reasonable heap segment for ABFD by looking at sbrk and
the static data sections. Store its limits in *BOTTOM and *TOP.
Return non-zero if successful. */
static int
derive_heap_segment (bfd *abfd, bfd_vma *bottom, bfd_vma *top)
{
bfd_vma top_of_data_memory = 0;
bfd_vma top_of_heap = 0;
bfd_size_type sec_size;
bfd_vma sec_vaddr;
asection *sec;
gdb_assert (bottom);
gdb_assert (top);
/* This function depends on being able to call a function in the
inferior. */
if (!target_has_execution)
return 0;
/* The following code assumes that the link map is arranged as
follows (low to high addresses):
---------------------------------
| text sections |
---------------------------------
| data sections (including bss) |
---------------------------------
| heap |
--------------------------------- */
for (sec = abfd->sections; sec; sec = sec->next)
{
if (bfd_get_section_flags (abfd, sec) & SEC_DATA
|| strcmp (".bss", bfd_section_name (abfd, sec)) == 0)
{
sec_vaddr = bfd_get_section_vma (abfd, sec);
sec_size = bfd_get_section_size (sec);
if (sec_vaddr + sec_size > top_of_data_memory)
top_of_data_memory = sec_vaddr + sec_size;
}
}
top_of_heap = call_target_sbrk (0);
if (top_of_heap == (bfd_vma) 0)
return 0;
/* Return results. */
if (top_of_heap > top_of_data_memory)
{
*bottom = top_of_data_memory;
*top = top_of_heap;
return 1;
}
/* No additional heap space needs to be saved. */
return 0;
}
static void
make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
{
int p_flags = 0;
int p_type = 0;
/* FIXME: these constants may only be applicable for ELF. */
if (startswith (bfd_section_name (obfd, osec), "load"))
p_type = PT_LOAD;
else if (startswith (bfd_section_name (obfd, osec), "note"))
p_type = PT_NOTE;
else
p_type = PT_NULL;
p_flags |= PF_R; /* Segment is readable. */
if (!(bfd_get_section_flags (obfd, osec) & SEC_READONLY))
p_flags |= PF_W; /* Segment is writable. */
if (bfd_get_section_flags (obfd, osec) & SEC_CODE)
p_flags |= PF_X; /* Segment is executable. */
bfd_record_phdr (obfd, p_type, 1, p_flags, 0, 0, 0, 0, 1, &osec);
}
/* find_memory_region_ftype implementation. DATA is 'bfd *' for the core file
GDB is creating. */
static int
gcore_create_callback (CORE_ADDR vaddr, unsigned long size, int read,
int write, int exec, int modified, void *data)
{
bfd *obfd = (bfd *) data;
asection *osec;
flagword flags = SEC_ALLOC | SEC_HAS_CONTENTS | SEC_LOAD;
/* If the memory segment has no permissions set, ignore it, otherwise
when we later try to access it for read/write, we'll get an error
or jam the kernel. */
if (read == 0 && write == 0 && exec == 0 && modified == 0)
{
if (info_verbose)
{
fprintf_filtered (gdb_stdout, "Ignore segment, %s bytes at %s\n",
plongest (size), paddress (target_gdbarch (), vaddr));
}
return 0;
}
if (write == 0 && modified == 0 && !solib_keep_data_in_core (vaddr, size))
{
/* See if this region of memory lies inside a known file on disk.
If so, we can avoid copying its contents by clearing SEC_LOAD. */
struct objfile *objfile;
struct obj_section *objsec;
ALL_OBJSECTIONS (objfile, objsec)
{
bfd *abfd = objfile->obfd;
asection *asec = objsec->the_bfd_section;
bfd_vma align = (bfd_vma) 1 << bfd_get_section_alignment (abfd,
asec);
bfd_vma start = obj_section_addr (objsec) & -align;
bfd_vma end = (obj_section_endaddr (objsec) + align - 1) & -align;
/* Match if either the entire memory region lies inside the
section (i.e. a mapping covering some pages of a large
segment) or the entire section lies inside the memory region
(i.e. a mapping covering multiple small sections).
This BFD was synthesized from reading target memory,
we don't want to omit that. */
if (objfile->separate_debug_objfile_backlink == NULL
&& ((vaddr >= start && vaddr + size <= end)
|| (start >= vaddr && end <= vaddr + size))
&& !(bfd_get_file_flags (abfd) & BFD_IN_MEMORY))
{
flags &= ~(SEC_LOAD | SEC_HAS_CONTENTS);
goto keep; /* Break out of two nested for loops. */
}
}
keep:;
}
if (write == 0)
flags |= SEC_READONLY;
if (exec)
flags |= SEC_CODE;
else
flags |= SEC_DATA;
osec = bfd_make_section_anyway_with_flags (obfd, "load", flags);
if (osec == NULL)
{
warning (_("Couldn't make gcore segment: %s"),
bfd_errmsg (bfd_get_error ()));
return 1;
}
if (info_verbose)
{
fprintf_filtered (gdb_stdout, "Save segment, %s bytes at %s\n",
plongest (size), paddress (target_gdbarch (), vaddr));
}
bfd_set_section_size (obfd, osec, size);
bfd_set_section_vma (obfd, osec, vaddr);
bfd_section_lma (obfd, osec) = 0; /* ??? bfd_set_section_lma? */
return 0;
}
int
objfile_find_memory_regions (struct target_ops *self,
find_memory_region_ftype func, void *obfd)
{
/* Use objfile data to create memory sections. */
struct objfile *objfile;
struct obj_section *objsec;
bfd_vma temp_bottom, temp_top;
/* Call callback function for each objfile section. */
ALL_OBJSECTIONS (objfile, objsec)
{
bfd *ibfd = objfile->obfd;
asection *isec = objsec->the_bfd_section;
flagword flags = bfd_get_section_flags (ibfd, isec);
/* Separate debug info files are irrelevant for gcore. */
if (objfile->separate_debug_objfile_backlink != NULL)
continue;
if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
{
int size = bfd_section_size (ibfd, isec);
int ret;
ret = (*func) (obj_section_addr (objsec), size,
1, /* All sections will be readable. */
(flags & SEC_READONLY) == 0, /* Writable. */
(flags & SEC_CODE) != 0, /* Executable. */
1, /* MODIFIED is unknown, pass it as true. */
obfd);
if (ret != 0)
return ret;
}
}
/* Make a stack segment. */
if (derive_stack_segment (&temp_bottom, &temp_top))
(*func) (temp_bottom, temp_top - temp_bottom,
1, /* Stack section will be readable. */
1, /* Stack section will be writable. */
0, /* Stack section will not be executable. */
1, /* Stack section will be modified. */
obfd);
/* Make a heap segment. */
if (derive_heap_segment (exec_bfd, &temp_bottom, &temp_top))
(*func) (temp_bottom, temp_top - temp_bottom,
1, /* Heap section will be readable. */
1, /* Heap section will be writable. */
0, /* Heap section will not be executable. */
1, /* Heap section will be modified. */
obfd);
return 0;
}
static void
gcore_copy_callback (bfd *obfd, asection *osec, void *ignored)
{
bfd_size_type size, total_size = bfd_section_size (obfd, osec);
file_ptr offset = 0;
/* Read-only sections are marked; we don't have to copy their contents. */
if ((bfd_get_section_flags (obfd, osec) & SEC_LOAD) == 0)
return;
/* Only interested in "load" sections. */
if (!startswith (bfd_section_name (obfd, osec), "load"))
return;
size = std::min (total_size, (bfd_size_type) MAX_COPY_BYTES);
gdb::byte_vector memhunk (size);
while (total_size > 0)
{
if (size > total_size)
size = total_size;
if (target_read_memory (bfd_section_vma (obfd, osec) + offset,
memhunk.data (), size) != 0)
{
warning (_("Memory read failed for corefile "
"section, %s bytes at %s."),
plongest (size),
paddress (target_gdbarch (), bfd_section_vma (obfd, osec)));
break;
}
if (!bfd_set_section_contents (obfd, osec, memhunk.data (),
offset, size))
{
warning (_("Failed to write corefile contents (%s)."),
bfd_errmsg (bfd_get_error ()));
break;
}
total_size -= size;
offset += size;
}
}
static int
gcore_memory_sections (bfd *obfd)
{
/* Try gdbarch method first, then fall back to target method. */
if (!gdbarch_find_memory_regions_p (target_gdbarch ())
|| gdbarch_find_memory_regions (target_gdbarch (),
gcore_create_callback, obfd) != 0)
{
if (target_find_memory_regions (gcore_create_callback, obfd) != 0)
return 0; /* FIXME: error return/msg? */
}
/* Record phdrs for section-to-segment mapping. */
bfd_map_over_sections (obfd, make_output_phdrs, NULL);
/* Copy memory region contents. */
bfd_map_over_sections (obfd, gcore_copy_callback, NULL);
return 1;
}
/* Provide a prototype to silence -Wmissing-prototypes. */
extern initialize_file_ftype _initialize_gcore;
void
_initialize_gcore (void)
{
add_com ("generate-core-file", class_files, gcore_command, _("\
Save a core file with the current state of the debugged process.\n\
Argument is optional filename. Default filename is 'core.<process_id>'."));
add_com_alias ("gcore", "generate-core-file", class_files, 1);
}
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