# emacs-buffer.gdb --- gdb macros for recovering buffers from emacs coredumps # Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc. # Maintainer: Noah Friedman # 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