Simple patch to implement $SUBJECT attached.
pg_signal_backend seems like the appropriate predefined role, because
pg_log_backend_memory_contexts() is implemented by a sending signal.
Regards,
Jeff Davis
From 473e0bb2e1ae0d56dbc6b0262c16b10c6c0454cc Mon Sep 17 00:00:00 2001
From: Jeff Davis <j...@j-davis.com>
Date: Fri, 22 Oct 2021 13:40:35 -0700
Subject: [PATCH] Allow pg_signal_backend members to call
pg_log_backend_memory_contexts().
---
src/backend/catalog/system_functions.sql | 5 +++++
src/backend/utils/adt/mcxtfuncs.c | 6 -----
src/include/catalog/catversion.h | 2 +-
src/test/regress/expected/misc_functions.out | 23 ++++++++++++++++++--
src/test/regress/sql/misc_functions.sql | 15 +++++++++++--
5 files changed, 40 insertions(+), 11 deletions(-)
diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql
index a416e94d371..2cd5e3fe17b 100644
--- a/src/backend/catalog/system_functions.sql
+++ b/src/backend/catalog/system_functions.sql
@@ -699,6 +699,8 @@ REVOKE EXECUTE ON FUNCTION pg_ls_dir(text) FROM public;
REVOKE EXECUTE ON FUNCTION pg_ls_dir(text,boolean,boolean) FROM public;
+REVOKE EXECUTE ON FUNCTION pg_log_backend_memory_contexts(integer) FROM PUBLIC;
+
--
-- We also set up some things as accessible to standard roles.
--
@@ -713,6 +715,9 @@ GRANT EXECUTE ON FUNCTION pg_ls_tmpdir() TO pg_monitor;
GRANT EXECUTE ON FUNCTION pg_ls_tmpdir(oid) TO pg_monitor;
+GRANT EXECUTE ON FUNCTION pg_log_backend_memory_contexts(integer)
+ TO pg_signal_backend;
+
GRANT pg_read_all_settings TO pg_monitor;
GRANT pg_read_all_stats TO pg_monitor;
diff --git a/src/backend/utils/adt/mcxtfuncs.c b/src/backend/utils/adt/mcxtfuncs.c
index 0d52613bc32..e06280ad712 100644
--- a/src/backend/utils/adt/mcxtfuncs.c
+++ b/src/backend/utils/adt/mcxtfuncs.c
@@ -177,12 +177,6 @@ pg_log_backend_memory_contexts(PG_FUNCTION_ARGS)
int pid = PG_GETARG_INT32(0);
PGPROC *proc;
- /* Only allow superusers to log memory contexts. */
- if (!superuser())
- ereport(ERROR,
- (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
- errmsg("must be a superuser to log memory contexts")));
-
proc = BackendPidGetProc(pid);
/*
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 3253b8751b1..039f6338604 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 202109101
+#define CATALOG_VERSION_NO 202110230
#endif
diff --git a/src/test/regress/expected/misc_functions.out b/src/test/regress/expected/misc_functions.out
index e845042d38d..38e36fec43e 100644
--- a/src/test/regress/expected/misc_functions.out
+++ b/src/test/regress/expected/misc_functions.out
@@ -138,14 +138,33 @@ HINT: No function matches the given name and argument types. You might need to
--
-- Memory contexts are logged and they are not returned to the function.
-- Furthermore, their contents can vary depending on the timing. However,
--- we can at least verify that the code doesn't fail.
+-- we can at least verify that the code doesn't fail, and that the
+-- permissions are set properly.
--
-SELECT * FROM pg_log_backend_memory_contexts(pg_backend_pid());
+SELECT pg_log_backend_memory_contexts(pg_backend_pid());
pg_log_backend_memory_contexts
--------------------------------
t
(1 row)
+CREATE ROLE testrole1 IN ROLE pg_signal_backend;
+CREATE ROLE testrole2;
+SELECT has_function_privilege('testrole1',
+ 'pg_log_backend_memory_contexts(integer)', 'EXECUTE'); -- yes
+ has_function_privilege
+------------------------
+ t
+(1 row)
+
+SELECT has_function_privilege('testrole2',
+ 'pg_log_backend_memory_contexts(integer)', 'EXECUTE'); -- no
+ has_function_privilege
+------------------------
+ f
+(1 row)
+
+DROP ROLE testrole1;
+DROP ROLE testrole2;
--
-- Test some built-in SRFs
--
diff --git a/src/test/regress/sql/misc_functions.sql b/src/test/regress/sql/misc_functions.sql
index a398349afc6..abf8b33b11c 100644
--- a/src/test/regress/sql/misc_functions.sql
+++ b/src/test/regress/sql/misc_functions.sql
@@ -35,9 +35,20 @@ SELECT num_nulls();
--
-- Memory contexts are logged and they are not returned to the function.
-- Furthermore, their contents can vary depending on the timing. However,
--- we can at least verify that the code doesn't fail.
+-- we can at least verify that the code doesn't fail, and that the
+-- permissions are set properly.
--
-SELECT * FROM pg_log_backend_memory_contexts(pg_backend_pid());
+
+SELECT pg_log_backend_memory_contexts(pg_backend_pid());
+
+CREATE ROLE testrole1 IN ROLE pg_signal_backend;
+CREATE ROLE testrole2;
+SELECT has_function_privilege('testrole1',
+ 'pg_log_backend_memory_contexts(integer)', 'EXECUTE'); -- yes
+SELECT has_function_privilege('testrole2',
+ 'pg_log_backend_memory_contexts(integer)', 'EXECUTE'); -- no
+DROP ROLE testrole1;
+DROP ROLE testrole2;
--
-- Test some built-in SRFs
--
2.17.1
