New versions of perl trigger warnings within perl.h with our compiler
flags. At least -Wdeclaration-after-statement, -Wshadow=compatible-local are
known to be problematic.
To avoid these warnings, conditionally use #pragma GCC system_header before
including plperl.h.
Alternatively, we could add the include paths for problematic headers with
-isystem, but that is a larger hammer and is harder to search for.
A more granular alternative would be to use #pragma GCC diagnostic
push/ignored/pop, but gcc warns about unknown warnings being ignored, so every
to-be-ignored-temporarily compiler warning would require its own pg_config.h
symbol and #ifdef.
As the warnings are voluminous, it makes sense to backpatch this change. But
don't do so yet, we first want gather buildfarm coverage - it's e.g. possible
that some compiler claiming to be gcc compatible has issues with the pragma.
Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: Discussion: https://postgr.es/m/20221228182455.hfdwd22zztvkojy2@awork3.anarazel.de
Strawberry uses __builtin_expect which Visual C doesn't have. For this
case define it as a noop. Solution taken from vim sources.
Backpatch to all live branches
Commit 121d2d3d70 included simd.h into pg_wchar.h. This caused a problem
on Windows, since Perl has "#define free" (referring to globals), which
breaks the Windows' header. To fix, move the static inline function
definitions from plperl_helpers.h, into plperl.h, where we already
document the necessary inclusion order. Since those functions were the
only reason for the existence of plperl_helpers.h, remove it.
First reported by Justin Pryzby
Diagnosis and review by Andres Freund, patch by myself per suggestion
from Tom Lane
Discussion: https://www.postgresql.org/message-id/20220826115546.GE2342%40telsasoft.com
Also apply the changes suggested by running
perl ppport.h --compat-version=5.8.0
And remove some no-longer-required NEED_foo declarations.
Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/87y278s6iq.fsf@wibble.ilmari.org
This completes the task begun in commit 1408d5d86, to synchronize
ECPG's exported definitions with the definition of bool used by
c.h (and, therefore, the one actually in use in the ECPG library).
On practically all modern platforms, ecpglib.h will now just
include <stdbool.h>, which should surprise nobody anymore.
That removes a header-inclusion-order hazard for ECPG clients,
who previously might get build failures or unexpected behavior
depending on whether they'd included <stdbool.h> themselves,
and if so, whether before or after ecpglib.h.
On platforms where sizeof(_Bool) is not 1 (only old PPC-based
Mac systems, as far as I know), things are still messy, as
inclusion of <stdbool.h> could still break ECPG client code.
There doesn't seem to be any clean fix for that, and given the
probably-negligible population of users who would care anymore,
it's not clear we should go far out of our way to cope with it.
This change at least fixes some header-inclusion-order hazards
for our own code, since c.h and ecpglib.h previously disagreed
on whether bool should be char or unsigned char.
To implement this with minimal invasion of ECPG client namespace,
move the choice of whether to rely on <stdbool.h> into configure,
and have it export a configuration symbol PG_USE_STDBOOL.
ecpglib.h no longer exports definitions for TRUE and FALSE,
only their lowercase brethren. We could undo that if we get
push-back about it.
Ideally we'd back-patch this as far as v11, which is where c.h
started to rely on <stdbool.h>. But the odds of creating problems
for formerly-working ECPG client code seem about as large as the
odds of fixing any non-working cases, so we'll just do this in HEAD.
Discussion: https://postgr.es/m/CAA4eK1LmaKO7Du9M9Lo=kxGU8sB6aL8fa3sF6z6d5yYYVe3BuQ@mail.gmail.com
Perl likes to redefine the _() macro:
#ifdef CAN_PROTOTYPE
#define _(args) args
#else ...
There was lots not to like about the way we dealt with this before:
1. Instead of taking care of the conflict centrally in plperl.h, we
expected every one of its ever-growing number of includers to do so.
This is duplicative and error-prone in itself, plus it means that
plperl.h fails to meet the expectation of being compilable standalone,
resulting in macro-redefinition warnings in cpluspluscheck.
2. We left _() with its Perl definition, meaning that if someone tried
to use it in any Perl-related extension, it would silently fail to
provide run-time translation. I don't see any live bugs of this ilk,
but it's clearly a hard-to-notice bug waiting to happen.
So fix that by centralizing the cleanup logic, making it match what
we're already doing for other macro conflicts with Perl. Since we only
expect plperl.h to be included by extensions not core code, we should
redefine _() as dgettext() not gettext().
A warning on a NetBSD box revealed to me that pg_waldump/compat.c
is using vprintf(), which snprintf.c did not provide coverage for.
This is not good if we want to have uniform *printf behavior, and
it's pretty silly to omit when it's a one-line function.
I also noted that snprintf.c has pg_vsprintf() but for some reason
it was not exposed to the outside world, creating another way in
which code might accidentally invoke the platform *printf family.
Let's just make sure that we replace all eight of the POSIX-standard
printf family.
Also, upgrade plperl.h and plpython.h to make sure that they do
their undefine/redefine rain dance for all eight, not some random
maybe-sufficient subset thereof.
We must define the macro "printf" with arguments, else it can mess
up format archetype attributes in builds where PG_PRINTF_ATTRIBUTE
is just "printf". Fortunately, that's easy to do now that we're
requiring C99; we can use __VA_ARGS__.
On the other hand, it's better not to use __VA_ARGS__ for the rest
of the *printf crew, so that one can take the addresses of those
functions without surprises.
I'd proposed doing this some time ago, but forgot to make it happen;
buildfarm failures subsequent to 96bf88d52 reminded me.
Discussion: https://postgr.es/m/22709.1535135640@sss.pgh.pa.us
Discussion: https://postgr.es/m/20180926190934.ea4xvzhkayuw7gkx@alap3.anarazel.de
We've spent an awful lot of effort over the years in coping with
platform-specific vagaries of the *printf family of functions. Let's just
forget all that mess and standardize on always using src/port/snprintf.c.
This gets rid of a lot of configure logic, and it will allow a saner
approach to dealing with %m (though actually changing that is left for
a follow-on patch).
Preliminary performance testing suggests that as it stands, snprintf.c is
faster than the native printf functions for some tasks on some platforms,
and slower for other cases. A pending patch will improve that, though
cases with floating-point conversions will doubtless remain slower unless
we want to put a *lot* of effort into that. Still, we've not observed
that *printf is really a performance bottleneck for most workloads, so
I doubt this matters much.
Patch by me, reviewed by Michael Paquier
Discussion: https://postgr.es/m/2975.1526862605@sss.pgh.pa.us
The code previously undefined isnan because of a compiler warning on
MinGW. Since we now need to use isnan, we can't do that anymore.
We might need a different solution if the compiler warning is too
annoying.
In the case that PostgreSQL uses stdbool.h but Perl doesn't, we need to
prevent Perl from defining bool, to prevent compiler warnings about
redefinition.
Revert the PL/Perl-specific change in
9a95a77d9d5d3003d2d67121f2731b6e5fc37336. We must not prevent Perl from
using stdbool.h when it has been built to do so, even if it uses an
incompatible size. Otherwise, we would be imposing our bool on Perl,
which will lead to crashes because of the size mismatch.
Instead, we undef bool after including the Perl headers, as we did
previously, but now only if we are not using stdbool.h ourselves.
Record that choice in c.h as USE_STDBOOL. This will also make it easier
to apply that coding pattern elsewhere if necessary.
Using the standard bool type provided by C allows some recent compilers
and debuggers to give better diagnostics. Also, some extension code and
third-party headers are increasingly pulling in stdbool.h, so it's
probably saner if everyone uses the same definition.
But PostgreSQL code is not prepared to handle bool of a size other than
1, so we keep our own old definition if we encounter a stdbool.h with a
bool of a different size. (Among current build farm members, this only
applies to old macOS versions on PowerPC.)
To check that the used bool is of the right size, add a static
assertions about size of GinTernaryValue vs bool. This is currently the
only place that assumes that bool and char are of the same size.
Discussion: https://www.postgresql.org/message-id/flat/3a0fe7e1-5ed1-414b-9230-53bbc0ed1f49@2ndquadrant.com
In each of the supplied procedural languages (PL/pgSQL, PL/Perl,
PL/Python, PL/Tcl), add language-specific commit and rollback
functions/commands to control transactions in procedures in that
language. Add similar underlying functions to SPI. Some additional
cleanup so that transaction commit or abort doesn't blow away data
structures still used by the procedure call. Add execution context
tracking to CALL and DO statements so that transaction control commands
can only be issued in top-level procedure and block calls, not function
calls or other procedure or block calls.
- SPI
Add a new function SPI_connect_ext() that is like SPI_connect() but
allows passing option flags. The only option flag right now is
SPI_OPT_NONATOMIC. A nonatomic SPI connection can execute transaction
control commands, otherwise it's not allowed. This is meant to be
passed down from CALL and DO statements which themselves know in which
context they are called. A nonatomic SPI connection uses different
memory management. A normal SPI connection allocates its memory in
TopTransactionContext. For nonatomic connections we use PortalContext
instead. As the comment in SPI_connect_ext() (previously SPI_connect())
indicates, one could potentially use PortalContext in all cases, but it
seems safest to leave the existing uses alone, because this stuff is
complicated enough already.
SPI also gets new functions SPI_start_transaction(), SPI_commit(), and
SPI_rollback(), which can be used by PLs to implement their transaction
control logic.
- portalmem.c
Some adjustments were made in the code that cleans up portals at
transaction abort. The portal code could already handle a command
*committing* a transaction and continuing (e.g., VACUUM), but it was not
quite prepared for a command *aborting* a transaction and continuing.
In AtAbort_Portals(), remove the code that marks an active portal as
failed. As the comment there already predicted, this doesn't work if
the running command wants to keep running after transaction abort. And
it's actually not necessary, because pquery.c is careful to run all
portal code in a PG_TRY block and explicitly runs MarkPortalFailed() if
there is an exception. So the code in AtAbort_Portals() is never used
anyway.
In AtAbort_Portals() and AtCleanup_Portals(), we need to be careful not
to clean up active portals too much. This mirrors similar code in
PreCommit_Portals().
- PL/Perl
Gets new functions spi_commit() and spi_rollback()
- PL/pgSQL
Gets new commands COMMIT and ROLLBACK.
Update the PL/SQL porting example in the documentation to reflect that
transactions are now possible in procedures.
- PL/Python
Gets new functions plpy.commit and plpy.rollback.
- PL/Tcl
Gets new commands commit and rollback.
Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
This is necessary for ActivePerl 5.18 onwards and for Strawberry Perl.
It is not sufficient for 32-bit builds with newer Visual Studio; these
fail with error LINK2026. Back-patch to 9.3 (all supported versions).
Reported by Victor Wagner.
Discussion: https://postgr.es/m/20160326154321.7754ab8f@wagner.wagner.home
In Perl builds that define PERL_IMPLICIT_SYS, XSUB.h defines macros
that replace a whole lot of basic libc functions with Perl functions.
We can't tolerate that in plperl.c; it breaks at least PG_TRY and
probably other stuff. The core idea of this patch is to include XSUB.h
only in the .xs files where it's really needed, and to move any code
broken by PERL_IMPLICIT_SYS out of the .xs files and into plperl.c.
The reason this hasn't been a problem before is that our build techniques
did not result in PERL_IMPLICIT_SYS appearing as a #define in PL/Perl,
even on some platforms where Perl thinks it is defined. That's about to
change in order to fix a nasty portability issue, so we need this work to
make the code safe for that.
Rather unaccountably, the Perl people chose XSUB.h as the place to provide
the versions of the aTHX/aTHX_ macros that are needed by code that's not
explicitly aware of the MULTIPLICITY API conventions. Hence, just removing
XSUB.h from plperl.c fails miserably. But we can work around that by
defining PERL_NO_GET_CONTEXT (which would make the relevant stanza of
XSUB.h a no-op anyway). As explained in perlguts.pod, that means we need
to add a "dTHX" macro call in every C function that calls a Perl API
function. In most of them we just add this at the top; but since the
macro fetches the current Perl interpreter pointer, more care is needed
in functions that switch the active interpreter. Lack of the macro is
easily recognized since it results in bleats about "my_perl" not being
defined.
(A nice side benefit of this is that it significantly reduces the number
of fetches of the current interpreter pointer. On my machine, plperl.so
gets more than 10% smaller, and there's probably some performance win too.
We could reduce the number of fetches still more by decorating the code
with pTHX_/aTHX_ macros to pass the interpreter pointer around, as
explained by perlguts.pod; but that's a task for another day.)
Formatting note: pgindent seems happy to treat "dTHX;" as a declaration
so long as it's the first thing after the left brace, as we'd already
observed with respect to the similar macro "dSP;". If you try to put
it later in a set of declarations, pgindent puts ugly extra space
around it.
Having removed XSUB.h from plperl.c, we need only move the support
functions for spi_return_next and util_elog (both of which use PG_TRY)
out of the .xs files and into plperl.c. This seems sufficient to
avoid the known problems caused by PERL_IMPLICIT_SYS, although we
could move more code if additional issues emerge.
This will need to be back-patched, but first let's see what the
buildfarm makes of it.
Patch by me, with some help from Ashutosh Sharma
Discussion: https://postgr.es/m/CANFyU97OVQ3+Mzfmt3MhuUm5NwPU=-FtbNH5Eb7nZL9ua8=rcA@mail.gmail.com
Change pg_bsd_indent to follow upstream rules for placement of comments
to the right of code, and remove pgindent hack that caused comments
following #endif to not obey the general rule.
Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using
the published version of pg_bsd_indent, but a hacked-up version that
tried to minimize the amount of movement of comments to the right of
code. The situation of interest is where such a comment has to be
moved to the right of its default placement at column 33 because there's
code there. BSD indent has always moved right in units of tab stops
in such cases --- but in the previous incarnation, indent was working
in 8-space tab stops, while now it knows we use 4-space tabs. So the
net result is that in about half the cases, such comments are placed
one tab stop left of before. This is better all around: it leaves
more room on the line for comment text, and it means that in such
cases the comment uniformly starts at the next 4-space tab stop after
the code, rather than sometimes one and sometimes two tabs after.
Also, ensure that comments following #endif are indented the same
as comments following other preprocessor commands such as #else.
That inconsistency turns out to have been self-inflicted damage
from a poorly-thought-through post-indent "fixup" in pgindent.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
Perl's integers are pointer-sized, so can hold more than INT_MAX on LP64
platforms, and come in both signed (IV) and unsigned (UV). Floating
point values (NV) may also be larger than double.
Since Perl 5.19.4 array indices are SSize_t instead of I32, so allow up
to SSize_t_max on those versions. The limit is not imposed just by
av_extend's argument type, but all the array handling code, so remove
the speculative comment.
Dagfinn Ilmari Mannsåker
This reverts commit 16304a013432931e61e623c8d85e9fe24709d9ba, except
for its changes in src/port/snprintf.c; as well as commit
cac18a76bb6b08f1ecc2a85e46c9d2ab82dd9d23 which is no longer needed.
Fujii Masao reported that the previous commit caused failures in psql on
OS X, since if one exits the pager program early while viewing a query
result, psql sees an EPIPE error from fprintf --- and the wrapper function
thought that was reason to panic. (It's a bit surprising that the same
does not happen on Linux.) Further discussion among the security list
concluded that the risk of other such failures was far too great, and
that the one-size-fits-all approach to error handling embodied in the
previous patch is unlikely to be workable.
This leaves us again exposed to the possibility of the type of failure
envisioned in CVE-2015-3166. However, that failure mode is strictly
hypothetical at this point: there is no concrete reason to believe that
an attacker could trigger information disclosure through the supposed
mechanism. In the first place, the attack surface is fairly limited,
since so much of what the backend does with format strings goes through
stringinfo.c or psprintf(), and those already had adequate defenses.
In the second place, even granting that an unprivileged attacker could
control the occurrence of ENOMEM with some precision, it's a stretch to
believe that he could induce it just where the target buffer contains some
valuable information. So we concluded that the risk of non-hypothetical
problems induced by the patch greatly outweighs the security risks.
We will therefore revert, and instead undertake closer analysis to
identify specific calls that may need hardening, rather than attempt a
universal solution.
We have kept the portion of the previous patch that improved snprintf.c's
handling of errors when it calls the platform's sprintf(). That seems to
be an unalloyed improvement.
Security: CVE-2015-3166
All known standard library implementations of these functions can fail
with ENOMEM. A caller neglecting to check for failure would experience
missing output, information exposure, or a crash. Check return values
within wrappers and code, currently just snprintf.c, that bypasses the
wrappers. The wrappers do not return after an error, so their callers
need not check. Back-patch to 9.0 (all supported versions).
Popular free software standard library implementations do take pains to
bypass malloc() in simple cases, but they risk ENOMEM for floating point
numbers, positional arguments, large field widths, and large precisions.
No specification demands such caution, so this commit regards every call
to a printf family function as a potential threat.
Injecting the wrappers implicitly is a compromise between patch scope
and design goals. I would prefer to edit each call site to name a
wrapper explicitly. libpq and the ECPG libraries would, ideally, convey
errors to the caller rather than abort(). All that would be painfully
invasive for a back-patched security fix, hence this compromise.
Security: CVE-2015-3166
This improves on commit bbfd7edae5aa5ad5553d3c7e102f2e450d4380d4 by
making two simple changes:
* pg_attribute_noreturn now takes parentheses, ie pg_attribute_noreturn().
Likewise pg_attribute_unused(), pg_attribute_packed(). This reduces
pgindent's tendency to misformat declarations involving them.
* attributes are now always attached to function declarations, not
definitions. Previously some places were taking creative shortcuts,
which were not merely candidates for bad misformatting by pgindent
but often were outright wrong anyway. (It does little good to put a
noreturn annotation where callers can't see it.) In any case, if
we would like to believe that these macros can be used with non-gcc
compilers, we should avoid gratuitous variance in usage patterns.
I also went through and manually improved the formatting of a lot of
declarations, and got rid of excessively repetitive (and now obsolete
anyway) comments informing the reader what pg_attribute_printf is for.
Until now __attribute__() was defined to be empty for all compilers but
gcc. That's problematic because it prevents using it in other compilers;
which is necessary e.g. for atomics portability. It's also just
generally dubious to do so in a header as widely included as c.h.
Instead add pg_attribute_format_arg, pg_attribute_printf,
pg_attribute_noreturn macros which are implemented in the compilers that
understand them. Also add pg_attribute_noreturn and pg_attribute_packed,
but don't provide fallbacks, since they can affect functionality.
This means that external code that, possibly unwittingly, relied on
__attribute__ defined to be empty on !gcc compilers may now run into
warnings or errors on those compilers. But there shouldn't be many
occurances of that and it's hard to work around...
Discussion: 54B58BA3.8040302@ohmu.fi
Author: Oskari Saarenmaa, with some minor changes by me.
This quiets compiler warnings about redefined macros and unused Perl__unused variables. The
redefinition of snprintf and vsnprintf is something we want to avoid anyway, if we've
gone to the bother of setting up the macros to point to our implementation.
More generally, arrays are turned in Perl array references, and row and
composite types are turned into Perl hash references. This is done
recursively, in a way that's natural to every Perl programmer.
To avoid a backwards compatibility hit, the string representation of
each structure is also available if the function requests it.
Authors: Alexey Klyukin and Alex Hunsaker.
Some code cleanups by me.
quote_literal, quote_nullable, quote_ident,
encode_bytea, decode_bytea, looks_like_number,
encode_array_literal, encode_array_constructor.
Split SPI.xs into two - SPI.xs now contains only SPI functions. Remainder
are in new Util.xs.
Some more code and documentation cleanup along the way, as well as
adding some CVS markers to files missing them.
Original patch from Tim Bunce, with a little editing from me.
