Commit 8dd5b6ea authored by Paul Eggert's avatar Paul Eggert

Improve pdumper doc; say unexec is deprecated

Say that pdumping cannot redump unless -batch is used.  Say that
the traditional unexec dumping method is by default not available,
and is deprecated.  Don't call dump files "portable", as dump files
are not any more portable than the Emacs executables themselves.
Just call them "dump files".  Similar, prefer "portable dumper"
(since the dumper code is portable) to "portable dumping" (since
the dump file is not).  Be more systematic about calling them
"dump files" instead of "dumped images" or whatnot.
parent 29a7d73d
Pipeline #2535 passed with stage
in 51 minutes and 42 seconds
......@@ -61,10 +61,10 @@ can be one of the following:
@table @samp
@item pdump
@cindex portable dump file
Record the preloaded Lisp data in a @dfn{portable dump} file. This
@cindex dump file
Record the preloaded Lisp data in a @dfn{dump file}. This
method produces an additional data file which Emacs will load at
startup. The portable dump file is usually called @file{emacs.pdmp},
startup. The produced dump file is usually called @file{emacs.pdmp},
and is installed in the Emacs @code{exec-directory} (@pxref{Help
Functions}). This method is the most preferred one, as it does not
require Emacs to employ any special techniques of memory allocation,
......@@ -75,7 +75,7 @@ modern systems to enhance security and privacy.
@cindex bootstrapping Emacs
Like @samp{pdump}, but used while @dfn{bootstrapping} Emacs, when no
previous Emacs binary and no @file{*.elc} byte-compiled Lisp files are
available. The produced portable dump file is usually named
available. The produced dump file is usually named
@file{bootstrap-emacs.pdmp} in this case.
@item dump
......@@ -88,6 +88,8 @@ terminal, so that the tables of terminal information are empty in the
dumped Emacs.) This method is also known as @dfn{unexec}, because it
produces a program file from a running process, and thus is in some
sense the opposite of executing a program to start a process.
Although this method was the way that Emacs traditionally saved its
state, it is now deprecated.
@item bootstrap
Like @samp{dump}, but used when bootstrapping Emacs with the
......@@ -97,11 +99,11 @@ Like @samp{dump}, but used when bootstrapping Emacs with the
@cindex preloaded Lisp files
@vindex preloaded-file-list
The dumped @file{emacs} executable (also called a @dfn{pure} Emacs)
is the one which is installed. If the portable dumping was used to
is the one which is installed. If the portable dumper was used to
build Emacs, the @file{emacs} executable is actually an exact copy of
@file{temacs}, and the corresponding @file{emacs.pdmp} file is
installed as well. The variable @code{preloaded-file-list} stores a
list of the preloaded Lisp files recorded in the portable dump file or
list of the preloaded Lisp files recorded in the dump file or
in the dumped Emacs executable. If you port Emacs to a new operating
system, and are not able to implement dumping of any kind, then Emacs
must load @file{loadup.el} each time it starts.
......@@ -201,15 +203,19 @@ In the unlikely event that you need a more general functionality than
@code{before-init-hook} (@pxref{Startup Summary}).
@defun dump-emacs-portable to-file &optional track-referrers
This function dumps the current state of Emacs into a portable dump
This function dumps the current state of Emacs into a dump
file @var{to-file}, using the @code{pdump} method. Normally, the
portable dump file is called @file{@var{emacs-name}.dmp}, where
dump file is called @file{@var{emacs-name}.dmp}, where
@var{emacs-name} is the name of the Emacs executable file. The
optional argument @var{track-referrers}, if non-@code{nil}, causes the
portable dumping process keep additional information to help track
portable dumper to keep additional information to help track
down the provenance of object types that are not yet supported by the
@code{pdump} method.
Although the portable dumper code can run on many platforms, the dump
files that it produces are not portable---they can be loaded only by
the Emacs executable that dumped them.
If you want to use this function in an Emacs that was already dumped,
you must run Emacs with the @samp{-batch} option.
@end defun
......@@ -220,20 +226,20 @@ This function dumps the current state of Emacs into an executable file
@var{to-file}, using the @code{unexec} method. It takes symbols from
@var{from-file} (this is normally the executable file @file{temacs}).
This function cannot be used in an Emacs that was already dumped. If
Emacs was built without @code{unexec} support, this function will not
be available.
This function cannot be used in an Emacs that was already dumped.
This function is deprecated, and by default Emacs is built without
@code{unexec} support so this function is not available.
@end defun
@defun pdumper-stats
If the current Emacs session restored its state from a portable dump
If the current Emacs session restored its state from a dump
file, this function returns information about the dump file and the
time it took to restore the Emacs state. The value is an alist
@w{@code{((dumped-with-pdumper . t) (load-time . @var{time})
(dump-file-name . @var{file}))}},
where @var{file} is the name of the dump file, and @var{time} is the
time in seconds it took to restore the state from the dump file.
If the current session was not restored from a portable dump file, the
If the current session was not restored from a dump file, the
value is nil.
@end defun
......
......@@ -92,11 +92,6 @@ and in particular better supports the Address Space Layout
Randomization (ASLR) feature, a security technique used by most modern
operating systems.
Portable dumping can be disabled at configure time via the configure
option '--with-dumping=unexec' (but we don't recommend that, unless
the portable dumping doesn't work on your system for some
reason---please report such systems to the Emacs developers as bugs).
When built with the portable dumping support (which is the default),
Emacs looks for the 'emacs.pdmp' file, generated during the build, in
its data directory at startup, and loads the dumped state from there.
......@@ -104,6 +99,15 @@ The new command-line argument '--dump-file=FILE' allows to specify a
non-default '.pdmp' file to load the state from; see the node "Initial
Options" in the Emacs manual for more information.
An Emacs started via a dump file can create a new dump file only if it
was invoked with the -batch option.
Although the portable dumper has been tested, it may have a bug on
unusual platforms. If you require traditional unexec dumping you can
use the configure-time option '--with-dumping=unexec'; however, please
file a bug report describing the situation, as unexec dumping is
deprecated.
+++
** The new configure option '--enable-checking=structs' attempts to
check that the portable dumper code has been updated to match the last
......
......@@ -297,11 +297,7 @@ One way of doing this is to start with fx's dynamic loading, and use it
to implement things like auto-loaded buffer parsers and database
access in cases which need more than Lisp.
** Replace unexec with a more portable form of dumping
See eg https://lists.gnu.org/r/emacs-devel/2014-01/msg01034.html
https://lists.gnu.org/r/emacs-devel/2014-06/msg00452.html
One way is to provide portable undumping using mmap (per gerd design).
** Fix portable dumping so that you can redump without using -batch.
** Imenu could be extended into a file-structure browsing mechanism
using code like that of customize-groups.
......
......@@ -22,8 +22,7 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
/* We generate fingerprint.c and fingerprint.o from all the sources in
Emacs. This way, we have a unique value that we can use to pair
data files (like a portable dump image) with a specific build of
Emacs. */
data files (like a dump file) with a specific build of Emacs. */
extern volatile unsigned char fingerprint[32];
#endif
......@@ -354,8 +354,8 @@ Setting `init-file-user' does not prevent Emacs from loading
"File containing site-wide run-time initializations.
This file is loaded at run-time before `~/.emacs'. It contains inits
that need to be in place for the entire site, but which, due to their
higher incidence of change, don't make sense to load into Emacs's
dumped image. Thus, the run-time load order is: 1. file described in
higher incidence of change, don't make sense to put into Emacs's
dump file. Thus, the run-time load order is: 1. file described in
this variable, if non-nil; 2. `~/.emacs'; 3. `default.el'.
Don't use the `site-start.el' file for things some users may not like.
......
......@@ -4531,9 +4531,9 @@ mark_maybe_object (Lisp_Object obj)
void *po = XPNTR (obj);
/* If the pointer is in the dumped image and the dump has a record
/* If the pointer is in the dump image and the dump has a record
of the object starting at the place where the pointer points, we
definitely have an object. If the pointer is in the dumped image
definitely have an object. If the pointer is in the dump image
and the dump has no idea what the pointer is pointing at, we
definitely _don't_ have an object. */
if (pdumper_object_p (po))
......
......@@ -686,7 +686,7 @@ dump_error_to_string (enum pdumper_load_result result)
}
/* Find a path (absolute or relative) to the Emacs executable.
Called early in initialization by portable dump loading code, so we
Called early in initialization by portable dumper loading code, so we
can't use lisp and associated machinery. On success, *EXENAME is
set to a heap-allocated string giving a path to the Emacs
executable or to NULL if we can't determine the path immediately.
......@@ -801,12 +801,12 @@ load_pdump (int argc, char **argv)
;
/* TODO: maybe more thoroughly scrub process environment in order to
make this use case (loading a pdumper image in an unexeced emacs)
make this use case (loading a dump file in an unexeced emacs)
possible? Right now, we assume that things we don't touch are
zero-initialized, and in an unexeced Emacs, this assumption
doesn't hold. */
if (initialized)
fatal ("cannot load pdumper image in unexeced Emacs");
fatal ("cannot load dump file in unexeced Emacs");
/* Look for an explicitly-specified dump file. */
const char *path_exec = PATH_EXEC;
......
......@@ -1885,7 +1885,7 @@ init_minibuf_once_for_pdumper (void)
PDUMPER_IGNORE (minibuf_prompt_width);
/* We run this function on first initialization and whenever we
restore from a pdumper image. pdumper doesn't try to preserve
restore from a dump file. pdumper doesn't try to preserve
frames, windows, and so on, so reset everything related here. */
Vminibuffer_list = Qnil;
minibuf_level = 0;
......
......@@ -333,8 +333,8 @@ dump_fingerprint (char const *label,
fprintf (stderr, "%s: %.*s\n", label, hexbuf_size, hexbuf);
}
/* Format of an Emacs portable dump file. All offsets are relative to
the beginning of the file. An Emacs portable dump file is coupled
/* Format of an Emacs dump file. All offsets are relative to
the beginning of the file. An Emacs dump file is coupled
to exactly the Emacs binary that produced it, so details of
alignment and endianness are unimportant.
......@@ -3990,7 +3990,7 @@ dump_drain_deferred_symbols (struct dump_context *ctx)
DEFUN ("dump-emacs-portable",
Fdump_emacs_portable, Sdump_emacs_portable,
1, 2, 0,
doc: /* Dump current state of Emacs into portable dump file FILENAME.
doc: /* Dump current state of Emacs into dump file FILENAME.
If TRACK-REFERRERS is non-nil, keep additional debugging information
that can help track down the provenance of unsupported object
types. */)
......@@ -5470,14 +5470,14 @@ pdumper_record_wd (const char *wd)
DEFUN ("pdumper-stats", Fpdumper_stats, Spdumper_stats, 0, 0, 0,
doc: /* Return statistics about portable dumping used by this session.
If this Emacs sesion was started from a portable dump file,
If this Emacs session was started from a dump file,
the return value is an alist of the form:
((dumped-with-pdumper . t) (load-time . TIME) (dump-file-name . FILE))
where TIME is the time in seconds it took to restore Emacs state
from the dump file, and FILE is the name of the dump file.
Value is nil if this session was not started using a portable dump file.*/)
Value is nil if this session was not started using a dump file.*/)
(void)
{
if (!dumped_with_pdumper_p ())
......
......@@ -35,7 +35,7 @@ INLINE_HEADER_BEGIN
variables to which the Lisp heap points. It doesn't know anything
about other C variables. The functions below allow code from other
parts of Emacs to tell the portable dumper about other bits of
information to preserve in dumped images.
information to preserve in dump files.
These memory-records are themselves preserved in the dump, so call
the functions below only on the !initialized init path, just
......@@ -44,7 +44,7 @@ INLINE_HEADER_BEGIN
There are no special functions to preserve a global Lisp_Object.
You should just staticpro these. */
/* Remember the value of THING in dumped images. THING must not
/* Remember the value of THING in dump files. THING must not
contain any pointers or Lisp_Object variables: these values are not
valid across dump and load. */
#define PDUMPER_REMEMBER_SCALAR(thing) \
......
/* Dump an executable image.
/* Dump an executable file.
Copyright (C) 1985-1988, 1999, 2001-2019 Free Software Foundation,
Inc.
......
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