# emacs-buffer.gdb --- gdb macros for recovering buffers from emacs coredumps
# Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
# Maintainer: Noah Friedman <friedman@splode.com>
# Status: Works with Emacs 22.0.51.1 (prerelease) as of 2006-01-12.
# Older cvs snapshots, and released versions, will not work due to
# changes in lisp data structures. But there are older versions of
# this gdb script which work with those versions.
# Created: 2005-04-28
# This file is part of GNU Emacs.
#
# GNU Emacs 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 2, or (at your option)
# any later version.
#
# GNU Emacs 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 GNU Emacs; see the file COPYING. If not, write to the
# Free Software Foundation, Inc.; 51 Franklin Street, Fifth Floor;
# Boston, MA 02110-1301, USA.
# Commentary:
# This is a set of gdb macros for recovering the contents of buffers from
# an Emacs coredump; they may not always be file-backed or have a recent
# autosave.
#
# The Emacs executable must have debugging symbols for this to work.
# But you never strip Emacs, right?
#
# The main commands of interest are `ybuffer-list', `yfile-buffers',
# `ysave-buffer', and `ybuffer-contents'. The `y' prefix avoids any
# namespace collisions with emacs/src/.gdbinit.
# Example usage:
#
# $ gdb /export/src/emacs/2005-05-02--03-17/src/emacs core.emacs.6.9845
# Current directory is /u/noah/
# GNU gdb (6.1post-1.20040607.43rh)
# ...
# #0 0x400007a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
# (gdb) source emacs-buffer.gdb
# (gdb) ybuffer-list
# B# M Size Name Mode File
# -- - ---- ---- ---- ----
# 0 * 556 mail to emacs-devel@gnu.org Mail
# 1 * 0 *Minibuf-1* Fundamental
# 2 145769 ChangeLog Change Log /u/noah/lib/elisp/noahf/ChangeLog
# 3 6619 ascii-table.el Elisp /u/noah/lib/elisp/noahf/ascii-table.el
# 4 * 48396 *Messages* Fundamental
# 5 3191 *Apropos* Apropos
# 6 17642 init-21.el Elisp /u/noah/etc/init/emacs/init-21.el
# 7 333 cpuid.c C /u/noah/cpuid.c
# 8 230 src Dired
# 9 218 noah Dired
# 10 * 21 *Echo Area 0* Fundamental
# 11 * 0 *Echo Area 1* Fundamental
# 12 319952 *bbdb data* Text /u/noah/.bbdb
# (gdb) ysave-buffer 0 mail.save
# [Wrote buffer "mail to emacs-devel@gnu.org" to file mail.save]
# (gdb) quit
# $ ls -l mail.save
# -rw-rw-rw- 1 noah user 556 May 2 04:05 mail.save
# $
# Code:
# Force loading of symbols, enough to give us gdb_valbits etc.
set main
# When nonzero, display some extra diagnostics in various commands
set $yverbose = 1
set $yfile_buffers_only = 0
set $tagmask = (((long)1 << gdb_gctypebits) - 1)
set $valmask = gdb_use_lsb ? ~($tagmask) : ((long)1 << gdb_valbits) - 1
define ygetptr
set $ptr = $arg0
set $ptr = (gdb_use_union ? $ptr.u.val : $ptr & $valmask) | gdb_data_seg_bits
end
define ybuffer-list
set $files_only = $yfile_buffers_only
set $yfile_buffers_only = 0
if $yverbose
printf "B# M Size Name Mode File\n"
printf "-- - ---- ---- ---- ----\n"
end
set $i = 0
set $alist = Vbuffer_alist
while $alist != Qnil
ygetptr $alist
set $this = ((struct Lisp_Cons *) $ptr)->car
set $alist = ((struct Lisp_Cons *) $ptr)->u.cdr
# Vbuffer_alist elts are pairs of the form (name . buffer)
ygetptr $this
set $buf = ((struct Lisp_Cons *) $ptr)->u.cdr
ygetptr $buf
set $buf = (struct buffer *) $ptr
if ! ($files_only && $buf->filename == Qnil)
ygetptr $buf->name
set $name = ((struct Lisp_String *) $ptr)->data
set $modp = ($buf->text->modiff > $buf->text->save_modiff) ? '*' : ' '
ygetptr $buf->mode_name
set $mode = ((struct Lisp_String *) $ptr)->data
if $buf->filename != Qnil
ygetptr $buf->filename
printf "%2d %c %9d %-20s %-10s %s\n", \
$i, $modp, ($buf->text->z_byte - 1), $name, $mode, \
((struct Lisp_String *) $ptr)->data
else
printf "%2d %c %9d %-20s %-10s\n", \
$i, $modp, ($buf->text->z_byte - 1), $name, $mode
end
end
set $i++
end
end
document ybuffer-list
Display a list of buffer names, sizes, and other attributes.
The buffer number in the first column is used as an argument
to some other emacs-buffer recovery commands, e.g. `ysave-buffer'.
end
define yfile-buffers
set $yfile_buffers_only = 1
ybuffer-list
end
document yfile-buffers
Display a list of buffers which are associated with files.
This is like `ybuffer-list', but only buffers that were visiting files
are displayed.
end
define yset-buffer
set $i = $arg0
set $alist = Vbuffer_alist
while ($alist != Qnil && $i > 0)
ygetptr $alist
set $alist = ((struct Lisp_Cons *) $ptr)->u.cdr
set $i--
end
# Get car of alist; this is a pair (name . buffer)
ygetptr $alist
set $this = ((struct Lisp_Cons *) $ptr)->car
# Get the buffer object
ygetptr $this
set $this = ((struct Lisp_Cons *) $ptr)->u.cdr
ygetptr $this
set $ycurrent_buffer = (struct buffer *) $ptr
end
document yset-buffer
Set current buffer (for other emacs-buffer recovery commands) to the ARG'th
buffer as displayed by `ybuffer-list'.
end
define yget-buffer-pointers
yset-buffer $arg0
set $buf = $ycurrent_buffer->text
set $beg = $buf->beg
set $gap = $beg + $buf->gpt_byte
set $gap_end = $gap + $buf->gap_size - 1
set $end = $gap_end + ($buf->z_byte - $buf->gpt_byte)
set $modp = $buf->modiff > $buf->save_modiff
#print *$beg@($gap - $beg)
#print *$gap_end@($end - $gap_end)
end
document yget-buffer-pointers
Update convenience variables with address pointers for the ARG'th buffer
as displayed by `ybuffer-list'.
This also sets the current buffer using `yset-buffer' (which see).
end
define yget-current-buffer-name
set $this = $ycurrent_buffer->name
ygetptr $this
set $ycurrent_buffer_name = ((struct Lisp_String *) $ptr)->data
end
document yget-current-buffer-name
Set $ycurrent_buffer_name to the name of the currently selected buffer.
end
define ycurrent-buffer
yget-current-buffer-name
printf "%s\n", $ycurrent_buffer_name
end
document ycurrent-buffer
Display the currently selected buffer.
end
define ydump-buffer
yget-buffer-pointers $arg0
if $buf->z_byte > 1
if $buf->z_byte <= $buf->gpt_byte
set $endptr = $beg + $buf->gpt_byte - 1
dump binary memory $arg1 $beg $endptr
else
dump binary memory $arg1 $beg $gap-1
append binary memory $arg1 $gap_end $end
set $endptr = $end
end
end
end
document ydump-buffer
Write contents of buffer N (as numbered according to `ybuffer-list') to
file FILE.
This is mainly used as an internal subroutine for `ysave-buffer' and
`ybuffer-contents', which see.
end
define ysave-buffer
ydump-buffer $arg0 $arg1
if $yverbose
yget-current-buffer-name
if $buf->z_byte <= 1
printf "[Buffer \"%s\" is empty.]\n", $ycurrent_buffer_name
else
# Output string broken into separate calls as necessary to avoid
# requiring a running process for evaluation.
printf "[Wrote buffer \"%s\" to file ", $ycurrent_buffer_name
echo $arg1]\n
end
end
end
document ysave-buffer
Save contents of buffer N (as numbered according to `ybuffer-list') to
file FILE.
end
define ybuffer-contents
ydump-buffer $arg0 /dev/stdout
if $yverbose && $buf->z_byte <= 1
yget-current-buffer-name
printf "[Buffer \"%s\" is empty.]\n", $ycurrent_buffer_name
else
if *($endptr-1) != '\n'
echo \n
end
end
end
document ybuffer-contents
Write contents of buffer N (numbered according to `ybuffer-list') to stdout.
end
# local variables:
# mode: gdb-script
# end:
# arch-tag: 02087f62-2663-4868-977a-1fbb2fc2e7ef