From 92fc1278786f3b135da19d11538e9d9b30f4b04a Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Mon, 23 Jan 2023 18:04:02 -0800 Subject: [PATCH] Fix error handling in libpqrcv_connect() When libpqrcv_connect (also known as walrcv_connect()) failed, it leaked the libpq connection. In most paths that's fairly harmless, as the calling process will exit soon after. But e.g. CREATE SUBSCRIPTION could lead to a somewhat longer lived leak. Fix by releasing resources, including the libpq connection, on error. Add a test exercising the error code path. To make it reliable and safe, the test tries to connect to port=-1, which happens to fail during connection establishment, rather than during connection string parsing. Reviewed-by: Noah Misch Discussion: https://postgr.es/m/20230121011237.q52apbvlarfv6jm6@awork3.anarazel.de Backpatch: 11- --- .../libpqwalreceiver/libpqwalreceiver.c | 26 +++++++++++-------- src/test/regress/expected/subscription.out | 10 ++++++- src/test/regress/sql/subscription.sql | 9 ++++++- 3 files changed, 32 insertions(+), 13 deletions(-) diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c index dab3152e6b..0e64d5ce20 100644 --- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c +++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c @@ -162,10 +162,7 @@ libpqrcv_connect(const char *conninfo, bool logical, const char *appname, conn->streamConn = PQconnectStartParams(keys, vals, /* expand_dbname = */ true); if (PQstatus(conn->streamConn) == CONNECTION_BAD) - { - *err = pchomp(PQerrorMessage(conn->streamConn)); - return NULL; - } + goto bad_connection_errmsg; /* * Poll connection until we have OK or FAILED status. @@ -207,10 +204,7 @@ libpqrcv_connect(const char *conninfo, bool logical, const char *appname, } while (status != PGRES_POLLING_OK && status != PGRES_POLLING_FAILED); if (PQstatus(conn->streamConn) != CONNECTION_OK) - { - *err = pchomp(PQerrorMessage(conn->streamConn)); - return NULL; - } + goto bad_connection_errmsg; if (logical) { @@ -221,9 +215,9 @@ libpqrcv_connect(const char *conninfo, bool logical, const char *appname, if (PQresultStatus(res) != PGRES_TUPLES_OK) { PQclear(res); - ereport(ERROR, - (errmsg("could not clear search path: %s", - pchomp(PQerrorMessage(conn->streamConn))))); + *err = psprintf(_("could not clear search path: %s"), + pchomp(PQerrorMessage(conn->streamConn))); + goto bad_connection; } PQclear(res); } @@ -231,6 +225,16 @@ libpqrcv_connect(const char *conninfo, bool logical, const char *appname, conn->logical = logical; return conn; + + /* error path, using libpq's error message */ +bad_connection_errmsg: + *err = pchomp(PQerrorMessage(conn->streamConn)); + + /* error path, error already set */ +bad_connection: + PQfinish(conn->streamConn); + pfree(conn); + return NULL; } /* diff --git a/src/test/regress/expected/subscription.out b/src/test/regress/expected/subscription.out index 1a7ca156ec..67cb15f4f5 100644 --- a/src/test/regress/expected/subscription.out +++ b/src/test/regress/expected/subscription.out @@ -71,7 +71,15 @@ ERROR: cannot enable subscription that does not have a slot name ALTER SUBSCRIPTION regress_testsub3 REFRESH PUBLICATION; ERROR: ALTER SUBSCRIPTION ... REFRESH is not allowed for disabled subscriptions DROP SUBSCRIPTION regress_testsub3; --- fail - invalid connection string +-- fail, connection string does not parse +CREATE SUBSCRIPTION regress_testsub5 CONNECTION 'i_dont_exist=param' PUBLICATION testpub; +ERROR: invalid connection string syntax: invalid connection option "i_dont_exist" + +-- fail, connection string parses, but doesn't work (and does so without +-- connecting, so this is reliable and safe) +CREATE SUBSCRIPTION regress_testsub5 CONNECTION 'port=-1' PUBLICATION testpub; +ERROR: could not connect to the publisher: invalid port number: "-1" +-- fail - invalid connection string during ALTER ALTER SUBSCRIPTION regress_testsub CONNECTION 'foobar'; ERROR: invalid connection string syntax: missing "=" after "foobar" in connection info string diff --git a/src/test/regress/sql/subscription.sql b/src/test/regress/sql/subscription.sql index 277b9290db..f0d38ad19b 100644 --- a/src/test/regress/sql/subscription.sql +++ b/src/test/regress/sql/subscription.sql @@ -56,7 +56,14 @@ ALTER SUBSCRIPTION regress_testsub3 REFRESH PUBLICATION; DROP SUBSCRIPTION regress_testsub3; --- fail - invalid connection string +-- fail, connection string does not parse +CREATE SUBSCRIPTION regress_testsub5 CONNECTION 'i_dont_exist=param' PUBLICATION testpub; + +-- fail, connection string parses, but doesn't work (and does so without +-- connecting, so this is reliable and safe) +CREATE SUBSCRIPTION regress_testsub5 CONNECTION 'port=-1' PUBLICATION testpub; + +-- fail - invalid connection string during ALTER ALTER SUBSCRIPTION regress_testsub CONNECTION 'foobar'; \dRs+