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nmischnmisch
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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
@@ -13369,6 +13369,17 @@ fi
1336913369

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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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@@ -13526,6 +13537,72 @@ fi
1352613537

1352713538
done
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13540+
{ $as_echo "$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
@@ -1061,10 +1061,39 @@ 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])])
10621062
fi
10631063

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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
1068+
# non-OpenLDAP implementations are safe. The dblink test suite exercises the
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# hazardous interaction directly.
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1071+
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(
1074+
[#include <ldap.h>
1075+
#if !defined(LDAP_VENDOR_VERSION) || \
1076+
(defined(LDAP_API_FEATURE_X_OPENLDAP) && \
1077+
LDAP_VENDOR_VERSION >= 20424 && LDAP_VENDOR_VERSION <= 20431)
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choke me
1079+
#endif], [])],
1080+
[pgac_cv_ldap_safe=yes],
1081+
[pgac_cv_ldap_safe=no])])
1082+
1083+
if test "$pgac_cv_ldap_safe" != yes; then
1084+
AC_MSG_WARN([
1085+
*** With OpenLDAP versions 2.4.24 through 2.4.31, inclusive, each backend
1086+
*** process that loads libpq (via WAL receiver, dblink, or postgres_fdw) and
1087+
*** also uses LDAP will crash on exit.])
1088+
fi])
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10641092
if test "$with_ldap" = yes ; then
10651093
if test "$PORTNAME" != "win32"; then
10661094
AC_CHECK_HEADERS(ldap.h, [],
10671095
[AC_MSG_ERROR([header file <ldap.h> is required for LDAP])])
1096+
PGAC_LDAP_SAFE
10681097
else
10691098
AC_CHECK_HEADERS(winldap.h, [],
10701099
[AC_MSG_ERROR([header file <winldap.h> is required for LDAP])],

‎contrib/dblink/Makefile

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Original file line numberDiff line numberDiff line change
@@ -7,7 +7,9 @@ SHLIB_LINK = $(libpq)
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88
DATA_built = dblink.sql
99
DATA = uninstall_dblink.sql
10-
REGRESS = dblink
10+
REGRESS = paths dblink
11+
REGRESS_OPTS = --dbname=$(CONTRIB_TESTDB) --dlpath=$(top_builddir)/src/test/regress
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EXTRA_CLEAN = sql/paths.sql expected/paths.out
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# the db name is hard-coded in the tests

‎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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@@ -115,6 +115,29 @@ SELECT *
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FROM dblink('SELECT * FROM foo') AS t(a int, b text, c text[])
116116
WHERE t.a > 7;
117117
ERROR: connection not available
118+
-- The first-level connection's backend will crash on exit given OpenLDAP
119+
-- [2.4.24, 2.4.31]. We won't see evidence of any crash until the victim
120+
-- process terminates and the postmaster responds. If process termination
121+
-- entails writing a core dump, that can take awhile. Wait for the process to
122+
-- vanish. At that point, the postmaster has called waitpid() on the crashed
123+
-- process, and it will accept no new connections until it has reinitialized
124+
-- the cluster. (We can't exploit pg_stat_activity, because the crash happens
125+
-- after the backend updates shared memory to reflect its impending exit.)
126+
DO $pl$
127+
BEGIN
128+
PERFORM wait_pid(crash_pid)
129+
FROM dblink('dbname=contrib_regression', $$
130+
SELECT pg_backend_pid() FROM dblink(
131+
'service=test_ldap dbname=contrib_regression',
132+
-- This string concatenation is a hack to shoehorn a
133+
-- set_pgservicefile call into the SQL statement.
134+
'SELECT 1' || set_pgservicefile('pg_service.conf')
135+
) t(c int)
136+
$$) AS t(crash_pid int);
137+
EXCEPTION WHEN sqlclient_unable_to_establish_sqlconnection THEN
138+
-- Expect "syntax error in service file" in a non-LDAP build.
139+
END
140+
$pl$;
118141
-- create a persistent connection
119142
SELECT dblink_connect('dbname=contrib_regression');
120143
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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-- Initialization that requires path substitution.
2+
CREATE FUNCTION putenv(text)
3+
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@'
9+
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 @@
1+
# pg_service.conf for minimally exercising libpq use of LDAP.
2+
3+
# 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.
6+
[test_ldap]
7+
ldap://127.0.0.1:9/base?attribute?one?filter

‎contrib/dblink/sql/.gitignore

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

‎contrib/dblink/sql/dblink.sql

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@@ -78,6 +78,30 @@ SELECT *
7878
FROM dblink('SELECT * FROM foo') AS t(a int, b text, c text[])
7979
WHERE t.a > 7;
8080

81+
-- The first-level connection's backend will crash on exit given OpenLDAP
82+
-- [2.4.24, 2.4.31]. We won't see evidence of any crash until the victim
83+
-- process terminates and the postmaster responds. If process termination
84+
-- entails writing a core dump, that can take awhile. Wait for the process to
85+
-- vanish. At that point, the postmaster has called waitpid() on the crashed
86+
-- process, and it will accept no new connections until it has reinitialized
87+
-- the cluster. (We can't exploit pg_stat_activity, because the crash happens
88+
-- after the backend updates shared memory to reflect its impending exit.)
89+
DO $pl$
90+
BEGIN
91+
PERFORM wait_pid(crash_pid)
92+
FROM dblink('dbname=contrib_regression', $$
93+
SELECT pg_backend_pid() FROM dblink(
94+
'service=test_ldap dbname=contrib_regression',
95+
-- This string concatenation is a hack to shoehorn a
96+
-- set_pgservicefile call into the SQL statement.
97+
'SELECT 1' || set_pgservicefile('pg_service.conf')
98+
) t(c int)
99+
$$) AS t(crash_pid int);
100+
EXCEPTION WHEN sqlclient_unable_to_establish_sqlconnection THEN
101+
-- Expect "syntax error in service file" in a non-LDAP build.
102+
END
103+
$pl$;
104+
81105
-- create a persistent connection
82106
SELECT dblink_connect('dbname=contrib_regression');
83107

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