If an interactive psql session used \gset when querying a compromised
server, the attacker could execute arbitrary code as the operating
system account running psql. Using a prefix not found among specially
treated variables, e.g. every lowercase string, precluded the attack.
Fix by issuing a warning and setting no variable for the column in
question. Users wanting the old behavior can use a prefix and then a
meta-command like "\set HISTSIZE :prefix_HISTSIZE". Back-patch to 9.5
(all supported versions).
Reviewed by Robert Haas. Reported by Nick Cleaton.
Security: CVE-2020-25696
This is still using the 2.0 version of pg_bsd_indent.
I thought it would be good to commit this separately,
so as to document the differences between 2.0 and 2.1 behavior.
Discussion: https://postgr.es/m/16296.1558103386@sss.pgh.pa.us
The original placement of this module in src/fe_utils/ is ill-considered,
because several src/common/ modules have dependencies on it, meaning that
libpgcommon and libpgfeutils now have mutual dependencies. That makes it
pointless to have distinct libraries at all. The intended design is that
libpgcommon is lower-level than libpgfeutils, so only dependencies from
the latter to the former are acceptable.
We already have the precedent that fe_memutils and a couple of other
modules in src/common/ are frontend-only, so it's not stretching anything
out of whack to treat logging.c as a frontend-only module in src/common/.
To the extent that such modules help provide a common frontend/backend
environment for the rest of common/ to use, it's a reasonable design.
(logging.c does not yet provide an ereport() emulation, but one can
dream.)
Hence, move these files over, and revert basically all of the build-system
changes made by commit cc8d41511. There are no places that need to grow
new dependencies on libpgcommon, further reinforcing the idea that this
is the right solution.
Discussion: https://postgr.es/m/a912ffff-f6e4-778a-c86a-cf5c47a12933@2ndquadrant.com
This unifies the various ad hoc logging (message printing, error
printing) systems used throughout the command-line programs.
Features:
- Program name is automatically prefixed.
- Message string does not end with newline. This removes a common
source of inconsistencies and omissions.
- Additionally, a final newline is automatically stripped, simplifying
use of PQerrorMessage() etc., another common source of mistakes.
- I converted error message strings to use %m where possible.
- As a result of the above several points, more translatable message
strings can be shared between different components and between
frontends and backend, without gratuitous punctuation or whitespace
differences.
- There is support for setting a "log level". This is not meant to be
user-facing, but can be used internally to implement debug or
verbose modes.
- Lazy argument evaluation, so no significant overhead if logging at
some level is disabled.
- Some color in the messages, similar to gcc and clang. Set
PG_COLOR=auto to try it out. Some colors are predefined, but can be
customized by setting PG_COLORS.
- Common files (common/, fe_utils/, etc.) can handle logging much more
simply by just using one API without worrying too much about the
context of the calling program, requiring callbacks, or having to
pass "progname" around everywhere.
- Some programs called setvbuf() to make sure that stderr is
unbuffered, even on Windows. But not all programs did that. This
is now done centrally.
Soft goals:
- Reduces vertical space use and visual complexity of error reporting
in the source code.
- Encourages more deliberate classification of messages. For example,
in some cases it wasn't clear without analyzing the surrounding code
whether a message was meant as an error or just an info.
- Concepts and terms are vaguely aligned with popular logging
frameworks such as log4j and Python logging.
This is all just about printing stuff out. Nothing affects program
flow (e.g., fatal exits). The uses are just too varied to do that.
Some existing code had wrappers that do some kind of print-and-exit,
and I adapted those.
I tried to keep the output mostly the same, but there is a lot of
historical baggage to unwind and special cases to consider, and I
might not always have succeeded. One significant change is that
pg_rewind used to write all error messages to stdout. That is now
changed to stderr.
Reviewed-by: Donald Dong <xdong@csumb.edu>
Reviewed-by: Arthur Zakirov <a.zakirov@postgrespro.ru>
Discussion: https://www.postgresql.org/message-id/flat/6a609b43-4f57-7348-6480-bd022f924310@2ndquadrant.com
It is equivalent in ANSI C to write (*funcptr) () and funcptr(). These
two styles have been applied inconsistently. After discussion, we'll
use the more verbose style for plain function pointer variables, to make
it clear that it's a variable, and the shorter style when the function
pointer is in a struct (s.func() or s->func()), because then it's clear
that it's not a plain function name, and otherwise the excessive
punctuation makes some of those invocations hard to read.
Discussion: https://www.postgresql.org/message-id/f52c16db-14ed-757d-4b48-7ef360b1631d@2ndquadrant.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 e3860ffa4d 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
Modify FETCH_COUNT to always have a defined value, like other control
variables, mainly so it will always appear in "\set" output.
Add hooks to force HISTSIZE to be defined and require it to have an
integer value. (I don't see any point in allowing it to be set to
non-integral values.)
Add hooks to force IGNOREEOF to be defined and require it to have an
integer value. Unlike the other cases, here we're trying to be
bug-compatible with a rather bogus externally-defined behavior, so I think
we need to continue to allow "\set IGNOREEOF whatever". Fix it so that
the substitution hook silently replace non-numeric values with "10",
so that the stored value always reflects what we're really doing.
Add a dummy assign hook for HISTFILE, just so it's always in
variables.c's list. We can't require it to be defined always, because
that would break the interaction with the PSQL_HISTORY environment
variable, so there isn't any change in visible behavior here.
Remove tab-complete.c's private list of known variable names, since that's
really a maintenance nuisance. Given the preceding changes, there are no
control variables it won't show anyway. This does mean that if for some
reason you've unset one of the status variables (DBNAME, HOST, etc), that
variable would not appear in tab completion for \set. But I think that's
fine, for at least two reasons: we shouldn't be encouraging people to use
those variables as regular variables, and if someone does do so anyway,
why shouldn't it act just like a regular variable?
Remove ugly and no-longer-used-anywhere GetVariableNum(). In general,
future additions of integer-valued control variables should follow the
paradigm of adding an assign hook using ParseVariableNum(), so there's
no reason to expect we'd need this again later.
Discussion: https://postgr.es/m/17516.1485973973@sss.pgh.pa.us
"\set" with no arguments displays all defined variables, but it does so
in the order that they appear in variables.c's list, which previously
was mostly creation order. That makes the list ugly and hard to find
things in, and it exposes some psql implementation details to users.
(For instance, ordinary variables will move to the bottom of the list
if unset and set again, but variables that have hooks won't.)
Fix that by keeping the list in alphabetical order at all times, which
isn't much more complicated than breaking out of the insertion search
loops once we reach an entry that should be after the one to be inserted.
Discussion: https://postgr.es/m/31785.1485900786@sss.pgh.pa.us
This commit improves on the results of commit 511ae628f in two ways:
1. It restores the historical behavior that "\set FOO" is interpreted
as setting FOO to "on", if FOO is a boolean control variable. We
already found one test script that was expecting that behavior, and
the psql documentation certainly does nothing to discourage people
from assuming that would work, since it often says just "if FOO is set"
when describing the effects of a boolean variable. However, now this
case will result in actually setting FOO to "on", not an empty string.
2. It arranges for an "\unset" of a control variable to set the value
back to its default value, rather than becoming apparently undefined.
The control variables are also initialized that way at psql startup.
In combination, these things guarantee that a control variable always
has a displayable value that reflects what psql is actually doing.
That is a pretty substantial usability improvement.
The implementation involves adding a second type of variable hook function
that is able to replace a proposed new value (including NULL) with another
one. We could alternatively have complicated the API of the assign hook,
but this way seems better since many variables can share the same
substitution hook function.
Also document the actual behavior of these variables more fully,
including covering assorted behaviors that were there before but
never documented.
This patch also includes some minor cleanup that should have been in
511ae628f but was missed.
Patch by me, but it owes a lot to discussions with Daniel Vérité.
Discussion: https://postgr.es/m/9572.1485821620@sss.pgh.pa.us
Previously, if the user set a special variable such as ECHO to an
unrecognized value, psql would bleat but store the new value anyway, and
then fall back to a default setting for the behavior controlled by the
variable. This was agreed to be a not particularly good idea. With
this patch, invalid values result in an error message and no change in
state.
(But this applies only to variables that affect psql's behavior; purely
informational variables such as ENCODING can still be set to random
values.)
To do this, modify the API for psql's assign-hook functions so that they
can return an OK/not OK result, and give them the responsibility for
printing error messages when they reject a value. Adjust the APIs for
ParseVariableBool and ParseVariableNum to support the new behavior
conveniently.
In passing, document the variable VERSION, which had somehow escaped that.
And improve the quite-inadequate commenting in psql/variables.c.
Daniel Vérité, reviewed by Rahila Syed, some further tweaking by me
Discussion: https://postgr.es/m/7356e741-fa59-4146-a8eb-cf95fd6b21fb@mm
This gets us to a point where psqlscan.l can be used by other frontend
programs for the same purpose psql uses it for, ie to detect when it's
collected a complete SQL command from input that is divided across
line boundaries. Moreover, other programs can supply their own lexers
for backslash commands of their own choosing. A follow-on patch will
use this in pgbench.
The end result here is roughly the same as in Kyotaro Horiguchi's
0001-Make-SQL-parser-part-of-psqlscan-independent-from-ps.patch, although
the details of the method for switching between lexers are quite different.
Basically, in this patch we share the entire PsqlScanState, YY_BUFFER_STATE
stack, *and* yyscan_t between different lexers. The only thing we need
to do to switch to a different lexer is to make sure the start_state is
valid for the new lexer. This works because flex doesn't keep any other
persistent state that depends on the specific lexing tables generated for
a particular .l file. (We are assuming that both lexers are built with
the same flex version, or at least versions that are compatible with
respect to the contents of yyscan_t; but that doesn't seem likely to
be a big problem in practice, considering how slowly flex changes.)
Aside from being more efficient than Horiguchi-san's original solution,
this avoids possible corner-case changes in semantics: the original code
was capable of popping the input buffer stack while still staying in
backslash-related parsing states. I'm not sure that that equates to any
useful user-visible behaviors, but I'm not sure it doesn't either, so
I'm loath to assume that we only need to consider the topmost buffer when
parsing a backslash command.
I've attempted to update the MSVC build scripts for the added .l file,
but will rely on the buildfarm to see if I missed anything.
Kyotaro Horiguchi and Tom Lane
For simple boolean variables such as ON_ERROR_STOP, psql has for a long
time recognized variant spellings of "on" and "off" (such as "1"/"0"),
and it also made a point of warning you if you'd misspelled the setting.
But these conveniences did not exist for other keyword-valued variables.
In particular, though ECHO_HIDDEN and ON_ERROR_ROLLBACK include "on" and
"off" as possible values, none of the alternative spellings for those were
recognized; and to make matters worse the code would just silently assume
"on" was meant for any unrecognized spelling. Several people have reported
getting bitten by this, so let's fix it. In detail, this patch:
* Allows all spellings recognized by ParseVariableBool() for ECHO_HIDDEN
and ON_ERROR_ROLLBACK.
* Reports a warning for unrecognized values for COMP_KEYWORD_CASE, ECHO,
ECHO_HIDDEN, HISTCONTROL, ON_ERROR_ROLLBACK, and VERBOSITY.
* Recognizes all values for all these variables case-insensitively;
previously there was a mishmash of case-sensitive and case-insensitive
behaviors.
Back-patch to all supported branches. There is a small risk of breaking
existing scripts that were accidentally failing to malfunction; but the
consensus is that the chance of detecting real problems and preventing
future mistakes outweighs this.
The Solaris Studio compiler warns about these instances, unlike more
mainstream compilers such as gcc. But manual inspection showed that
the code is clearly not reachable, and we hope no worthy compiler will
complain about removing this code.
existing for backend GUC variables, and use this to eliminate repeated
fetching/parsing of psql variables in psql's inner loops. In a trivial
test with lots of 'select 1;' commands, psql's CPU time went down almost
10%, although of course the effect on total elapsed time was much less.
Per discussion about how to ensure the upcoming FETCH_COUNT patch doesn't
cost any performance when not being used.
GetVariable() and be consistent about treatment of the list header.
Motivated by noticing strspn() taking an unreasonable percentage of
runtime --- the call removed from GetVariable() was the only one that
could be in a high-usage path ...
places --- that risks corrupting data structures, losing sync with the
backend, etc. We now longjmp only from calls to readline, fgets, and
fread, which we assume are coded to protect themselves against interrupts
at undesirable times. This requires adding explicit tests for
cancel_pressed in long-running loops, but on the whole it's far cleaner.
Martijn van Oosterhout and Tom Lane.
little more sane. Some parts of the code was using a static function
xmalloc() that did safe memory allocation (where "safe" means "bail
out on OOM"), but most of it was just invoking calloc() or malloc()
directly. Now almost everything invokes xmalloc() or xcalloc().
Bruce Momjian
Noah Misch
Amit Kapila
Tom Lane
Peter Eisentraut
Peter Eisentraut
Magnus Hagander
Neil Conway
PostgreSQL Daemon