upstream/postgresql
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2026-04-28 17:49:35 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions
Base de données relationnelle
54731 commits 38 branches 679 tags 847 MiB
C 84.5%
PLpgSQL 6.2%
Perl 4.9%
Yacc 1.2%
Meson 0.7%
Other 2.4%
Find a file
Tom Lane 80ef926758 Improve our ability to detect bogus pointers passed to pfree et al. 
Commit c6e0fe1f2 was a shade too trusting that any pointer passed
to pfree, repalloc, etc will point at a valid chunk.  Notably,
passing a pointer that was actually obtained from malloc tended
to result in obscure assertion failures, if not worse.  (On FreeBSD
I've seen such mistakes take down the entire cluster, seemingly as
a result of clobbering shared memory.)

To improve matters, extend the mcxt_methods[] array so that it
has entries for every possible MemoryContextMethodID bit-pattern,
with the currently unassigned ID codes pointing to error-reporting
functions.  Then, fiddle with the ID assignments so that patterns
likely to be associated with bad pointers aren't valid ID codes.
In particular, we should avoid assigning bit patterns 000 (zeroed
memory) and 111 (wipe_mem'd memory).

It turns out that on glibc (Linux), malloc uses chunk headers that
have flag bits in the same place we keep MemoryContextMethodID,
and that the bit patterns 000, 001, 010 are the only ones we'll
see as long as the backend isn't threaded.  So we can have very
robust detection of pfree'ing a malloc-assigned block on that
platform, at least so long as we can refrain from using up those
ID codes.  On other platforms, we don't have such a good guarantee,
but keeping 000 reserved will be enough to catch many such cases.

While here, make GetMemoryChunkMethodID() local to mcxt.c, as there
seems no need for it to be exposed even in memutils_internal.h.

Patch by me, with suggestions from Andres Freund and David Rowley.

Discussion: https://postgr.es/m/2910981.1665080361@sss.pgh.pa.us
2022-10-06 21:24:00 -04:00
config meson: Add initial version of meson based build system 2022-09-21 22:37:17 -07:00
contrib meson: Add support for building with precompiled headers 2022-10-06 17:19:30 -07:00
doc doc: clarify description for log_startup_progress_interval 2022-10-05 15:53:40 -04:00
src Improve our ability to detect bogus pointers passed to pfree et al. 2022-10-06 21:24:00 -04:00
.cirrus.yml meson: Add support for building with precompiled headers 2022-10-06 17:19:30 -07:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add .editorconfig 2019-12-18 09:13:13 +01:00
.git-blame-ignore-revs Add b2e6e7682 to .git-blame-ignore-revs 2022-09-08 14:06:59 +07:00
.gitattributes Remove trailing whitespace from *.sgml files. 2022-04-20 11:04:49 -04:00
.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
aclocal.m4 Probe $PROVE not $PERL while checking for modules needed by TAP tests. 2021-11-22 12:54:52 -05:00
configure meson: Add initial version of meson based build system 2022-09-21 22:37:17 -07:00
configure.ac meson: Add initial version of meson based build system 2022-09-21 22:37:17 -07:00
COPYRIGHT Update copyright for 2022 2022-01-07 19:04:57 -05:00
GNUmakefile.in Run tests of libpq on installcheck-world, checkprep and check-world 2022-06-03 13:15:20 +09:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Dynamically find correct installation docs in Makefile. 2022-01-19 14:48:25 +01:00
meson.build meson: Add support for building with precompiled headers 2022-10-06 17:19:30 -07:00
meson_options.txt meson: Add initial version of meson based build system 2022-09-21 22:37:17 -07:00
README Canonicalize some URLs 2020-02-10 20:47:50 +01:00
README.git Canonicalize some URLs 2020-02-10 20:47:50 +01:00

README 

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.