Re: [PATCH 1/1] x86: Add process memory layout to coredump file
From: t cheney
Date: Sun Dec 11 2011 - 08:19:36 EST
This is readelf's patch which can retrieve maps in coredump
file, and it is based on binutils-2.21.1.
Usage: ./readelf -m coredumpfile
https://github.com/cdma/coredumpmap/blob/dev/readelf.c
https://github.com/cdma/coredumpmap/blob/dev/common.h
Alternately, following is diff's result:
changed files:
./binutils-2.21.1/binutils/readelf.c
./binutils-2.21.1/include/elf/common.h
diff -u ./binutils-2.21.1/binutils/readelf.c
./binutils-2.21.1/binutils/readelf.c.orig
--- ./binutils-2.21.1/binutils/readelf.c 2011-12-07
14:54:45.000000000 -0500
+++ ./binutils-2.21.1/binutils/readelf.c.orig 2011-12-07
14:53:43.000000000 -0500
@@ -196,7 +196,6 @@
static int do_notes;
static int do_archive_index;
static int is_32bit_elf;
-static int do_maps;
struct group_list
{
@@ -3072,7 +3071,6 @@
{"dyn-syms", no_argument, 0, OPTION_DYN_SYMS},
{"relocs", no_argument, 0, 'r'},
{"notes", no_argument, 0, 'n'},
- {"maps", no_argument, 0, 'm'},
{"dynamic", no_argument, 0, 'd'},
{"arch-specific", no_argument, 0, 'A'},
{"version-info", no_argument, 0, 'V'},
@@ -3112,7 +3110,6 @@
--symbols An alias for --syms\n\
--dyn-syms Display the dynamic symbol table\n\
-n --notes Display the core notes (if present)\n\
- -m --maps Display the core maps (if present)\n\
-r --relocs Display the relocations (if present)\n\
-u --unwind Display the unwind info (if present)\n\
-d --dynamic Display the dynamic section (if present)\n\
@@ -3231,7 +3228,7 @@
usage (stderr);
while ((c = getopt_long
- (argc, argv, "ADHINR:SVWacdeghi:lnp:rstuvw::x:m", options,
NULL)) != EOF)
+ (argc, argv, "ADHINR:SVWacdeghi:lnp:rstuvw::x:", options,
NULL)) != EOF)
{
switch (c)
{
@@ -3354,9 +3351,6 @@
case 'W':
do_wide++;
break;
- case 'm':
- do_maps++;
- break;
default:
/* xgettext:c-format */
error (_("Invalid option '-%c'\n"), c);
@@ -3370,7 +3364,7 @@
&& !do_segments && !do_header && !do_dump && !do_version
&& !do_histogram && !do_debugging && !do_arch && !do_notes
&& !do_section_groups && !do_archive_index
- && !do_dyn_syms && !do_maps)
+ && !do_dyn_syms)
usage (stderr);
else if (argc < 3)
{
@@ -11855,8 +11849,6 @@
return _("NT_LWPSINFO (lwpsinfo_t structure)");
case NT_WIN32PSTATUS:
return _("NT_WIN32PSTATUS (win32_pstatus structure)");
- case NT_MAPS:
- return _("NT_MAPS (maps info)");
default:
break;
}
@@ -11970,9 +11962,6 @@
{
const char * name = pnote->namesz ? pnote->namedata : "(NONE)";
const char * nt;
-
- if (do_maps && pnote->type != NT_MAPS)
- return 0;
if (pnote->namesz == 0)
/* If there is no note name, then use the default set of
@@ -12000,13 +11989,6 @@
nt = get_note_type (pnote->type);
printf (" %s\t\t0x%08lx\t%s\n", name, pnote->descsz, nt);
- if (do_maps && pnote->type == NT_MAPS)
- {
- pnote->descdata[pnote->descsz] = 0;
- printf("Maps is following:\n");
- printf("%s\n",pnote->descdata);
- }
-
return 1;
}
@@ -12093,6 +12075,7 @@
}
res &= process_note (& inote);
+
if (temp != NULL)
{
free (temp);
@@ -12150,7 +12133,7 @@
process_notes (FILE * file)
{
/* If we have not been asked to display the notes then do nothing. */
- if (! do_notes && !do_maps)
+ if (! do_notes)
return 1;
if (elf_header.e_type != ET_CORE)
diff -u ./binutils-2.21.1/include/elf/common.h
./binutils-2.21.1/include/elf/common.h.orig
--- ./binutils-2.21.1/include/elf/common.h 2011-12-07
14:56:02.000000000 -0500
+++ ./binutils-2.21.1/include/elf/common.h.orig 2011-12-07
14:55:45.000000000 -0500
@@ -518,7 +518,6 @@
#define NT_PRPSINFO 3 /* Contains copy of prpsinfo struct */
#define NT_TASKSTRUCT 4 /* Contains copy of task struct */
#define NT_AUXV 6 /* Contains copy of Elfxx_auxv_t */
-#define NT_MAPS 7 /* Contains copy of maps*/
#define NT_PRXFPREG 0x46e62b7f /* Contains a user_xfpregs_struct; */
/* note name must be "LINUX". */
#define NT_PPC_VMX 0x100 /* PowerPC Altivec/VMX registers */
On 12/11/11, t cheney <cdmalord@xxxxxxxxx> wrote:
> On 12/11/11, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
>> t cheney <cdmalord@xxxxxxxxx> writes:
>>
>>> This patch just add memory layout(same as /proc/pid/maps) to
>>> coredump file. The layout is appended to corenote segment with
>>> flag NT_MAPS=7.
>>
>> Seems like a reasonable idea, but can you please share code with
>> the proc implementation?
> Yes, I will post it in following mail.
>>
>> It's a bit unusal to have ASCII in a coredump, but I suppose expressing
>> this in binary would be somewhat ugly.
>>
>>> + char *buf = notes->data;
>>> + size_t core_limit = notes->datasz;
>>> + gate_vma = get_gate_vma(current->mm);
>>> +
> The maps info is appended to core notes segment in which there are all
> ASCII text such as regs,signal and thread info.
>>
>> It seems a bit dubious to do this without locking even in a core dump.
>>
>>> + for (vma = first_vma(current, gate_vma); vma != NULL;
>>> + vma = next_vma(vma, gate_vma)) {
>>> + flags = vma->vm_flags;
>>> + maps_size += len;
>>> + if (file) {
>>> + if (maps_size > core_limit)
>>> + break;
>>
>> You have a one-off bug here. Also below.
>>
>>> + DUMP_WRITE(buf, len, foffset);
>>> + }
>>
> Because proceses that could change vma pages are blocked in do_exit,
> here vma pages are safe.
>>
>> -Andi
>> --
>> ak@xxxxxxxxxxxxxxx -- Speaking for myself only
>>
>
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