The previous API for this function had it returning a malloc'd string.
That meant that callers had to check for NULL return, which few of them
were doing, and it also meant that callers had to remember to free()
the string later, which required extra logic in most cases.
Instead, make simple_prompt() write into a buffer supplied by the caller.
Anywhere that the maximum required input length is reasonably small,
which is almost all of the callers, we can just use a local or static
array as the buffer instead of dealing with malloc/free.
A fair number of callers used "pointer == NULL" as a proxy for "haven't
requested the password yet". Maintaining the same behavior requires
adding a separate boolean flag for that, which adds back some of the
complexity we save by removing free()s. Nonetheless, this nets out
at a small reduction in overall code size, and considerably less code
than we would have had if we'd added the missing NULL-return checks
everywhere they were needed.
In passing, clean up the API comment for simple_prompt() and get rid
of a very-unnecessary malloc/free in its Windows code path.
This is nominally a bug fix, but it does not seem worth back-patching,
because the actual risk of an OOM failure in any of these places seems
pretty tiny, and all of them are client-side not server-side anyway.
This patch is by me, but it owes a great deal to Michael Paquier
who identified the problem and drafted a patch for fixing it the
other way.
Discussion: <CAB7nPqRu07Ot6iht9i9KRfYLpDaF2ZuUv5y_+72uP23ZAGysRg@mail.gmail.com>
Due to simplistic quoting and confusion of database names with conninfo
strings, roles with the CREATEDB or CREATEROLE option could escalate to
superuser privileges when a superuser next ran certain maintenance
commands. The new coding rule for PQconnectdbParams() calls, documented
at conninfo_array_parse(), is to pass expand_dbname=true and wrap
literal database names in a trivial connection string. Escape
zero-length values in appendConnStrVal(). Back-patch to 9.1 (all
supported versions).
Nathan Bossart, Michael Paquier, and Noah Misch. Reviewed by Peter
Eisentraut. Reported by Nathan Bossart.
Security: CVE-2016-5424
A pointless and confusing error message is shown to the user when
attempting to identify a 9.3 or older remote server with a 9.5/9.6
pg_receivexlog, because the return signature of IDENTIFY_SYSTEM was
changed in 9.4. There's no good reason for the warning message, so
shuffle code around to keep it quiet.
(pg_recvlogical is also affected by this commit, but since it obviously
cannot work with 9.3 that doesn't actually matter much.)
Backpatch to 9.5.
Reported by Marco Nenciarini, who also wrote the initial patch. Further
tweaked by Robert Haas and Fujii Masao; reviewed by Michael Paquier and
Craig Ringer.
Per Coverity (not that any of these are so non-obvious that they should not
have been caught before commit). The extent of leakage is probably minor
to unnoticeable, but a leak is a leak. Back-patch as necessary.
Michael Paquier
pg_receivexlog and pg_recvlogical error out when --create-slot is
specified and a slot with the same name already exists. In some cases,
especially with pg_receivexlog, that's rather annoying and requires
additional scripting.
Backpatch to 9.5 as slot control functions have newly been added to
pg_receivexlog, and there doesn't seem much point leaving it in a less
useful state.
Discussion: 20150619144755.GG29350@alap3.anarazel.de
CreateReplicationSlot() and DropReplicationSlot() were not cleaning up
the query buffer in some cases (mostly error conditions) which meant a
small leak. Not generally an issue as the error case would result in an
immediate exit, but not difficult to fix either and reduces the number
of false positives from code analyzers.
In passing, also add appropriate PQclear() calls to RunIdentifySystem().
Pointed out by Coverity.
Move some more code to manage replication connection command to
streamutil.c. A later patch will introduce replication slot via
pg_receivexlog and this avoid duplicating relevant code between
pg_receivexlog and pg_recvlogical.
Author: Michael Paquier, with some editing by me.
Replication slots are a crash-safe data structure which can be created
on either a master or a standby to prevent premature removal of
write-ahead log segments needed by a standby, as well as (with
hot_standby_feedback=on) pruning of tuples whose removal would cause
replication conflicts. Slots have some advantages over existing
techniques, as explained in the documentation.
In a few places, we refer to the type of replication slots introduced
by this patch as "physical" slots, because forthcoming patches for
logical decoding will also have slots, but with somewhat different
properties.
Andres Freund and Robert Haas
The previous coding was fairly unreadable and drew double-free warnings
from clang. I believe the double free was actually not reachable, because
PQconnectionNeedsPassword is coded to not return true if a password was
provided, so that the loop can't iterate more than twice. Nonetheless
it seems worth rewriting. No back-patch since this is just cosmetic.
In streamutil.c:GetConnection(), upgrade failure to parse the
connection string to an exit(1) instead of simply returning NULL.
Most callers already immediately exited, but pg_receivexlog would
loop on this case, continually trying to re-parse the connection
string (which can't be changed after pg_receivexlog has started).
GetConnection() was already expected to exit(1) in some cases
(eg: failure to allocate memory or if unable to determine the
integer_datetimes flag), so this change shouldn't surprise anyone.
Began looking at this due to the Coverity scanner complaining that
we were leaking err_msg in this case- no longer an issue since we
just exit(1) immediately.
Without this, there's no way to pass arbitrary libpq connection parameters
to these applications. It's a bit strange that the option is called
-d/--dbname, when in fact you can *not* pass a database name in it, but it's
consistent with other client applications where a connection string is also
passed using -d.
Original patch by Amit Kapila, heavily modified by me.
libpgcommon is a new static library to allow sharing code among the
various frontend programs and backend; this lets us eliminate duplicate
implementations of common routines. We avoid libpgport, because that's
intended as a place for porting issues; per discussion, it seems better
to keep them separate.
The first use case, and the only implemented by this patch, is pg_malloc
and friends, which many frontend programs were already using.
At the same time, we can use this to provide palloc emulation functions
for the frontend; this way, some palloc-using files in the backend can
also be used by the frontend cleanly. To do this, we change palloc() in
the backend to be a function instead of a macro on top of
MemoryContextAlloc(). This was previously believed to cause loss of
performance, but this implementation has been tweaked by Tom and Andres
so that on modern compilers it provides a slight improvement over the
previous one.
This lets us clean up some places that were already with
localized hacks.
Most of the pg_malloc/palloc changes in this patch were authored by
Andres Freund. Zoltán Böszörményi also independently provided a form of
that. libpgcommon infrastructure was authored by Álvaro.
On some platforms these functions return NULL, rather than the more common
practice of returning a pointer to a zero-sized block of memory. Hack our
various wrapper functions to hide the difference by substituting a size
request of 1. This is probably not so important for the callers, who
should never touch the block anyway if they asked for size 0 --- but it's
important for the wrapper functions themselves, which mistakenly treated
the NULL result as an out-of-memory failure. This broke at least pg_dump
for the case of no user-defined aggregates, as per report from
Matthew Carrington.
Back-patch to 9.2 to fix the pg_dump issue. Given the lack of previous
complaints, it seems likely that there is no live bug in previous releases,
even though some of these functions were in place before that.
We had a number of variants on the theme of "malloc or die", with the
majority named like "pg_malloc", but by no means all. Standardize on the
names pg_malloc, pg_malloc0, pg_realloc, pg_strdup. Get rid of pg_calloc
entirely in favor of using pg_malloc0.
This is an essentially cosmetic change, so no back-patch. (I did find
a couple of places where psql and pg_dump were using plain malloc or
strdup instead of the pg_ versions, but they don't look significant
enough to bother back-patching.)
The most user-visible part of this is to change the long options
--statusint and --noloop to --status-interval and --no-loop,
respectively, per discussion.
Also, consistently enclose file names in double quotes, per our
conventions; and consistently use the term "transaction log file" to
talk about WAL segments. (Someday we may need to go over this
terminology and make it consistent across the whole source code.)
Finally, reflow the code to better fit in 80 columns, and have pgindent
fix it up some more.
When the internal loop mode was added, freeing memory and closing
filedescriptors before returning became important, and a few cases
in the code missed that.
Fujii Masao
Add option for parallel streaming of the transaction log while a
base backup is running, to get the logfiles before the server has
removed them.
Also add a tool called pg_receivexlog, which streams the transaction
log into files, creating a log archive without having to wait for
segments to complete, thus decreasing the window of data loss without
having to waste space using archive_timeout. This works best in
combination with archive_command - suggested usage docs etc coming later.
Bruce Momjian
Tom Lane
Noah Misch
Alvaro Herrera
Andres Freund
Peter Eisentraut
Stephen Frost
Robert Haas
Heikki Linnakangas
Magnus Hagander