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Diagnose incompatible OpenLDAP versions during build and test.
With OpenLDAP versions 2.4.24 through 2.4.31, inclusive, PostgreSQL backends can crash at exit. Raise a warning during "configure" based on the compile-time OpenLDAP version number, and test the crash scenario in the dblink test suite. Back-patch to 9.0 (all supported versions).
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‎configure

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Original file line numberDiff line numberDiff line change
@@ -13663,6 +13663,17 @@ fi
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fi
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# PGAC_LDAP_SAFE
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# --------------
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# PostgreSQL sometimes loads libldap_r and plain libldap into the same
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# process. Check for OpenLDAP versions known not to tolerate doing so; assume
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# non-OpenLDAP implementations are safe. The dblink test suite exercises the
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# hazardous interaction directly.
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if test "$with_ldap" = yes ; then
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if test "$PORTNAME" != "win32"; then
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@@ -13820,6 +13831,72 @@ fi
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done
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13834+
{ $as_echo "$as_me:$LINENO: checking for compatible LDAP implementation" >&5
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$as_echo_n "checking for compatible LDAP implementation... " >&6; }
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if test "${pgac_cv_ldap_safe+set}" = set; then
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$as_echo_n "(cached) " >&6
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else
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cat >conftest.$ac_ext <<_ACEOF
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/* confdefs.h. */
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_ACEOF
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cat confdefs.h >>conftest.$ac_ext
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cat >>conftest.$ac_ext <<_ACEOF
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/* end confdefs.h. */
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#include <ldap.h>
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#if !defined(LDAP_VENDOR_VERSION) || \
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(defined(LDAP_API_FEATURE_X_OPENLDAP) && \
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LDAP_VENDOR_VERSION >= 20424 && LDAP_VENDOR_VERSION <= 20431)
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choke me
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#endif
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int
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main ()
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{
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;
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return 0;
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}
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_ACEOF
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rm -f conftest.$ac_objext
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if { (ac_try="$ac_compile"
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case "(($ac_try" in
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*\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
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*) ac_try_echo=$ac_try;;
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esac
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eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
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$as_echo "$ac_try_echo") >&5
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(eval "$ac_compile") 2>conftest.er1
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ac_status=$?
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grep -v '^ *+' conftest.er1 >conftest.err
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rm -f conftest.er1
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cat conftest.err >&5
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$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
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(exit $ac_status); } && {
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test -z "$ac_c_werror_flag" ||
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test ! -s conftest.err
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} && test -s conftest.$ac_objext; then
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pgac_cv_ldap_safe=yes
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else
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$as_echo "$as_me: failed program was:" >&5
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sed 's/^/| /' conftest.$ac_ext >&5
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pgac_cv_ldap_safe=no
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fi
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rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
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fi
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{ $as_echo "$as_me:$LINENO: result: $pgac_cv_ldap_safe" >&5
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$as_echo "$pgac_cv_ldap_safe" >&6; }
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if test "$pgac_cv_ldap_safe" != yes; then
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{ $as_echo "$as_me:$LINENO: WARNING:
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*** With OpenLDAP versions 2.4.24 through 2.4.31, inclusive, each backend
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*** process that loads libpq (via WAL receiver, dblink, or postgres_fdw) and
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*** also uses LDAP will crash on exit." >&5
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$as_echo "$as_me: WARNING:
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*** With OpenLDAP versions 2.4.24 through 2.4.31, inclusive, each backend
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*** process that loads libpq (via WAL receiver, dblink, or postgres_fdw) and
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*** also uses LDAP will crash on exit." >&2;}
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fi
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else
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for ac_header in winldap.h

‎configure.in

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Original file line numberDiff line numberDiff line change
@@ -1067,10 +1067,39 @@ if test "$with_libxslt" = yes ; then
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AC_CHECK_HEADER(libxslt/xslt.h, [], [AC_MSG_ERROR([header file <libxslt/xslt.h> is required for XSLT support])])
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fi
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# PGAC_LDAP_SAFE
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# --------------
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# PostgreSQL sometimes loads libldap_r and plain libldap into the same
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# process. Check for OpenLDAP versions known not to tolerate doing so; assume
1074+
# non-OpenLDAP implementations are safe. The dblink test suite exercises the
1075+
# hazardous interaction directly.
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AC_DEFUN([PGAC_LDAP_SAFE],
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[AC_CACHE_CHECK([for compatible LDAP implementation], [pgac_cv_ldap_safe],
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[AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
1080+
[#include <ldap.h>
1081+
#if !defined(LDAP_VENDOR_VERSION) || \
1082+
(defined(LDAP_API_FEATURE_X_OPENLDAP) && \
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LDAP_VENDOR_VERSION >= 20424 && LDAP_VENDOR_VERSION <= 20431)
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choke me
1085+
#endif], [])],
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[pgac_cv_ldap_safe=yes],
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[pgac_cv_ldap_safe=no])])
1088+
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if test "$pgac_cv_ldap_safe" != yes; then
1090+
AC_MSG_WARN([
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*** With OpenLDAP versions 2.4.24 through 2.4.31, inclusive, each backend
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*** process that loads libpq (via WAL receiver, dblink, or postgres_fdw) and
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*** also uses LDAP will crash on exit.])
1094+
fi])
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10701098
if test "$with_ldap" = yes ; then
10711099
if test "$PORTNAME" != "win32"; then
10721100
AC_CHECK_HEADERS(ldap.h, [],
10731101
[AC_MSG_ERROR([header file <ldap.h> is required for LDAP])])
1102+
PGAC_LDAP_SAFE
10741103
else
10751104
AC_CHECK_HEADERS(winldap.h, [],
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[AC_MSG_ERROR([header file <winldap.h> is required for LDAP])],

‎contrib/dblink/Makefile

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,9 @@ SHLIB_PREREQS = submake-libpq
99
EXTENSION = dblink
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DATA = dblink--1.0.sql dblink--unpackaged--1.0.sql
1111

12-
REGRESS = dblink
12+
REGRESS = paths dblink
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REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress
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EXTRA_CLEAN = sql/paths.sql expected/paths.out
1315

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# the db name is hard-coded in the tests
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override USE_MODULE_DB =

‎contrib/dblink/expected/.gitignore

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@@ -0,0 +1 @@
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/paths.out

‎contrib/dblink/expected/dblink.out

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@@ -105,6 +105,33 @@ SELECT *
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FROM dblink('SELECT * FROM foo') AS t(a int, b text, c text[])
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WHERE t.a > 7;
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ERROR: connection not available
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-- The first-level connection's backend will crash on exit given OpenLDAP
109+
-- [2.4.24, 2.4.31]. We won't see evidence of any crash until the victim
110+
-- process terminates and the postmaster responds. If process termination
111+
-- entails writing a core dump, that can take awhile. Wait for the process to
112+
-- vanish. At that point, the postmaster has called waitpid() on the crashed
113+
-- process, and it will accept no new connections until it has reinitialized
114+
-- the cluster. (We can't exploit pg_stat_activity, because the crash happens
115+
-- after the backend updates shared memory to reflect its impending exit.)
116+
DO $pl$
117+
DECLARE
118+
detail text;
119+
BEGIN
120+
PERFORM wait_pid(crash_pid)
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FROM dblink('dbname=contrib_regression', $$
122+
SELECT pg_backend_pid() FROM dblink(
123+
'service=test_ldap dbname=contrib_regression',
124+
-- This string concatenation is a hack to shoehorn a
125+
-- set_pgservicefile call into the SQL statement.
126+
'SELECT 1' || set_pgservicefile('pg_service.conf')
127+
) t(c int)
128+
$$) AS t(crash_pid int);
129+
EXCEPTION WHEN OTHERS THEN
130+
GET STACKED DIAGNOSTICS detail = PG_EXCEPTION_DETAIL;
131+
-- Expected error in a non-LDAP build.
132+
IF NOT detail LIKE 'syntax error in service file%' THEN RAISE; END IF;
133+
END
134+
$pl$;
108135
-- create a persistent connection
109136
SELECT dblink_connect('dbname=contrib_regression');
110137
dblink_connect

‎contrib/dblink/input/paths.source

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@@ -0,0 +1,14 @@
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-- Initialization that requires path substitution.
2+
3+
CREATE FUNCTION putenv(text)
4+
RETURNS void
5+
AS '@libdir@/regress@DLSUFFIX@', 'regress_putenv'
6+
LANGUAGE C STRICT;
7+
8+
CREATE FUNCTION wait_pid(int)
9+
RETURNS void
10+
AS '@libdir@/regress@DLSUFFIX@'
11+
LANGUAGE C STRICT;
12+
13+
CREATE FUNCTION set_pgservicefile(text) RETURNS void LANGUAGE SQL
14+
AS $$SELECT putenv('PGSERVICEFILE=@abs_srcdir@/' || $1)$$;

‎contrib/dblink/output/paths.source

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@@ -0,0 +1,11 @@
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-- Initialization that requires path substitution.
2+
CREATE FUNCTION putenv(text)
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RETURNS void
4+
AS '@libdir@/regress@DLSUFFIX@', 'regress_putenv'
5+
LANGUAGE C STRICT;
6+
CREATE FUNCTION wait_pid(int)
7+
RETURNS void
8+
AS '@libdir@/regress@DLSUFFIX@'
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LANGUAGE C STRICT;
10+
CREATE FUNCTION set_pgservicefile(text) RETURNS void LANGUAGE SQL
11+
AS $$SELECT putenv('PGSERVICEFILE=@abs_srcdir@/' || $1)$$;

‎contrib/dblink/pg_service.conf

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@@ -0,0 +1,7 @@
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# pg_service.conf for minimally exercising libpq use of LDAP.
2+
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# Having failed to reach an LDAP server, libpq essentially ignores the
4+
# "service=test_ldap" in its connection string. Contact the "discard"
5+
# service; the test works whether or not it answers.
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[test_ldap]
7+
ldap://127.0.0.1:9/base?attribute?one?filter

‎contrib/dblink/sql/.gitignore

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/paths.sql

‎contrib/dblink/sql/dblink.sql

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@@ -65,6 +65,34 @@ SELECT *
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FROM dblink('SELECT * FROM foo') AS t(a int, b text, c text[])
6666
WHERE t.a > 7;
6767

68+
-- The first-level connection's backend will crash on exit given OpenLDAP
69+
-- [2.4.24, 2.4.31]. We won't see evidence of any crash until the victim
70+
-- process terminates and the postmaster responds. If process termination
71+
-- entails writing a core dump, that can take awhile. Wait for the process to
72+
-- vanish. At that point, the postmaster has called waitpid() on the crashed
73+
-- process, and it will accept no new connections until it has reinitialized
74+
-- the cluster. (We can't exploit pg_stat_activity, because the crash happens
75+
-- after the backend updates shared memory to reflect its impending exit.)
76+
DO $pl$
77+
DECLARE
78+
detail text;
79+
BEGIN
80+
PERFORM wait_pid(crash_pid)
81+
FROM dblink('dbname=contrib_regression', $$
82+
SELECT pg_backend_pid() FROM dblink(
83+
'service=test_ldap dbname=contrib_regression',
84+
-- This string concatenation is a hack to shoehorn a
85+
-- set_pgservicefile call into the SQL statement.
86+
'SELECT 1' || set_pgservicefile('pg_service.conf')
87+
) t(c int)
88+
$$) AS t(crash_pid int);
89+
EXCEPTION WHEN OTHERS THEN
90+
GET STACKED DIAGNOSTICS detail = PG_EXCEPTION_DETAIL;
91+
-- Expected error in a non-LDAP build.
92+
IF NOT detail LIKE 'syntax error in service file%' THEN RAISE; END IF;
93+
END
94+
$pl$;
95+
6896
-- create a persistent connection
6997
SELECT dblink_connect('dbname=contrib_regression');
7098

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