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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
@@ -13796,6 +13796,17 @@ 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
1380113812

@@ -13953,6 +13964,72 @@ fi
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1395413965
done
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13967+
{ $as_echo "$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
@@ -1088,10 +1088,39 @@ if test "$with_libxslt" = yes ; then
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AC_CHECK_HEADER(libxslt/xslt.h, [], [AC_MSG_ERROR([header file <libxslt/xslt.h> is required for XSLT support])])
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fi
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# PGAC_LDAP_SAFE
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# --------------
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# PostgreSQL sometimes loads libldap_r and plain libldap into the same
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# process. Check for OpenLDAP versions known not to tolerate doing so; assume
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# non-OpenLDAP implementations are safe. The dblink test suite exercises the
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# hazardous interaction directly.
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AC_DEFUN([PGAC_LDAP_SAFE],
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[AC_CACHE_CHECK([for compatible LDAP implementation], [pgac_cv_ldap_safe],
1100+
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
1101+
[#include <ldap.h>
1102+
#if !defined(LDAP_VENDOR_VERSION) || \
1103+
(defined(LDAP_API_FEATURE_X_OPENLDAP) && \
1104+
LDAP_VENDOR_VERSION >= 20424 && LDAP_VENDOR_VERSION <= 20431)
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choke me
1106+
#endif], [])],
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[pgac_cv_ldap_safe=yes],
1108+
[pgac_cv_ldap_safe=no])])
1109+
1110+
if test "$pgac_cv_ldap_safe" != yes; then
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AC_MSG_WARN([
1112+
*** 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.])
1115+
fi])
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10911119
if test "$with_ldap" = yes ; then
10921120
if test "$PORTNAME" != "win32"; then
10931121
AC_CHECK_HEADERS(ldap.h, [],
10941122
[AC_MSG_ERROR([header file <ldap.h> is required for LDAP])])
1123+
PGAC_LDAP_SAFE
10951124
else
10961125
AC_CHECK_HEADERS(winldap.h, [],
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[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
@@ -9,7 +9,9 @@ SHLIB_PREREQS = submake-libpq
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EXTENSION = dblink
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DATA = dblink--1.0.sql dblink--unpackaged--1.0.sql
1111

12-
REGRESS = dblink
12+
REGRESS = paths dblink
13+
REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress
14+
EXTRA_CLEAN = sql/paths.sql expected/paths.out
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# the db name is hard-coded in the tests
1517
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 +105,29 @@ SELECT *
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FROM dblink('SELECT * FROM foo') AS t(a int, b text, c text[])
106106
WHERE t.a > 7;
107107
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+
BEGIN
118+
PERFORM wait_pid(crash_pid)
119+
FROM dblink('dbname=contrib_regression', $$
120+
SELECT pg_backend_pid() FROM dblink(
121+
'service=test_ldap dbname=contrib_regression',
122+
-- This string concatenation is a hack to shoehorn a
123+
-- set_pgservicefile call into the SQL statement.
124+
'SELECT 1' || set_pgservicefile('pg_service.conf')
125+
) t(c int)
126+
$$) AS t(crash_pid int);
127+
EXCEPTION WHEN sqlclient_unable_to_establish_sqlconnection THEN
128+
-- Expect "syntax error in service file" in a non-LDAP build.
129+
END
130+
$pl$;
108131
-- create a persistent connection
109132
SELECT dblink_connect('dbname=contrib_regression');
110133
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)
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RETURNS void
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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.
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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
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AS $$SELECT putenv('PGSERVICEFILE=@abs_srcdir@/' || $1)$$;

‎contrib/dblink/pg_service.conf

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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]
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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 +65,30 @@ 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+
BEGIN
78+
PERFORM wait_pid(crash_pid)
79+
FROM dblink('dbname=contrib_regression', $$
80+
SELECT pg_backend_pid() FROM dblink(
81+
'service=test_ldap dbname=contrib_regression',
82+
-- This string concatenation is a hack to shoehorn a
83+
-- set_pgservicefile call into the SQL statement.
84+
'SELECT 1' || set_pgservicefile('pg_service.conf')
85+
) t(c int)
86+
$$) AS t(crash_pid int);
87+
EXCEPTION WHEN sqlclient_unable_to_establish_sqlconnection THEN
88+
-- Expect "syntax error in service file" in a non-LDAP build.
89+
END
90+
$pl$;
91+
6892
-- create a persistent connection
6993
SELECT dblink_connect('dbname=contrib_regression');
7094

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