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help / color / mirror / Atom feedFrom: Justin Pryzby <[email protected]>
Subject: [PATCH 2/4] warn when setting GUC to a nonextant library
Date: Mon, 13 Dec 2021 08:42:38 -0600
Note that warnings shouldn't be issued during startup (only fatals):
$ ./tmp_install/usr/local/pgsql/bin/postgres -D ./testrun/regress/regress/tmp_check/data -c shared_preload_libraries=ab
2023-07-06 14:47:03.817 CDT postmaster[2608106] FATAL: could not access file "ab": No existe el archivo o el directorio
2023-07-06 14:47:03.817 CDT postmaster[2608106] CONTEXT: while loading shared libraries for setting "shared_preload_libraries"
---
src/backend/commands/variable.c | 101 ++++++++++++++++++
src/backend/utils/fmgr/dfmgr.c | 3 +-
src/backend/utils/misc/guc.c | 6 ++
src/backend/utils/misc/guc_tables.c | 6 +-
src/include/fmgr.h | 1 +
src/include/utils/guc_hooks.h | 7 ++
.../unsafe_tests/expected/rolenames.out | 19 ++++
.../modules/unsafe_tests/sql/rolenames.sql | 13 +++
8 files changed, 151 insertions(+), 5 deletions(-)
diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
index c9421b17952..0714b4421dc 100644
--- a/src/backend/commands/variable.c
+++ b/src/backend/commands/variable.c
@@ -40,6 +40,7 @@
#include "utils/timestamp.h"
#include "utils/tzparser.h"
#include "utils/varlena.h"
+#include <unistd.h>
/*
* DATESTYLE
@@ -1234,3 +1235,103 @@ check_ssl(bool *newval, void **extra, GucSource source)
#endif
return true;
}
+
+
+/*
+ * See also load_libraries() and internal_load_library().
+ */
+static bool
+check_preload_libraries(char **newval, void **extra, GucSource source,
+ bool restricted)
+{
+ char *rawstring;
+ List *elemlist;
+ ListCell *l;
+
+ /* nothing to do if empty */
+ if (newval == NULL || *newval[0] == '\0')
+ return true;
+
+ /*
+ * Issue warnings only during an interactive SET from ALTER
+ * ROLE/DATABASE/SYSTEM, and not while applying GUCs during startup,
+ * when relevant errors would be FATAL, and the warnings would be redundant.
+ *
+ * IsUnderPostmaster is a hack to allow warning under ALTER SYSTEM but
+ * not during startup. Both of which use PGC_S_FILE.
+ */
+ if (!IsUnderPostmaster)
+ return true;
+
+ /* Need a modifiable copy of string */
+ rawstring = pstrdup(*newval);
+
+ /* Parse string into list of filename paths */
+ if (!SplitDirectoriesString(rawstring, ',', &elemlist))
+ {
+ /* Should not happen ? */
+ return false;
+ }
+
+ foreach(l, elemlist)
+ {
+ /* Note that filename was already canonicalized */
+ char *filename = (char *) lfirst(l);
+ char *expanded = NULL;
+
+ /* If restricting, insert $libdir/plugins if not mentioned already */
+ if (restricted && first_dir_separator(filename) == NULL)
+ {
+ expanded = psprintf("$libdir/plugins/%s", filename);
+ filename = expanded;
+ }
+
+ filename = expand_dynamic_library_name(filename);
+
+ /*
+ * stat()/access() only check that the library exists, not that it has
+ * the correct magic number or even a library. But error messages
+ * from dlopen() are not portable, so it'd be hard to report any
+ * problem other than "does not exist".
+ */
+ if (access(filename, R_OK) == 0)
+ continue;
+
+ if (source == PGC_S_FILE)
+ /* ALTER SYSTEM */
+ ereport(WARNING,
+ errcode_for_file_access(),
+ errmsg("could not access file \"%s\"", filename),
+ errdetail("The server might fail to start with this setting."),
+ errhint("If the server is shut down, it will be necessary to manually edit the %s file to allow it to start again.",
+ "postgresql.auto.conf"));
+ else if (source == PGC_S_TEST)
+ /* ALTER ROLE/DATABASE */
+ ereport(WARNING,
+ errcode_for_file_access(),
+ errmsg("could not access file \"%s\"", filename),
+ errdetail("New sessions will fail to connect with the new setting."));
+ }
+
+ list_free_deep(elemlist);
+ pfree(rawstring);
+ return true;
+}
+
+bool
+check_shared_preload_libraries(char **newval, void **extra, GucSource source)
+{
+ return check_preload_libraries(newval, extra, source, false);
+}
+
+bool
+check_local_preload_libraries(char **newval, void **extra, GucSource source)
+{
+ return check_preload_libraries(newval, extra, source, true);
+}
+
+bool
+check_session_preload_libraries(char **newval, void **extra, GucSource source)
+{
+ return check_preload_libraries(newval, extra, source, false);
+}
diff --git a/src/backend/utils/fmgr/dfmgr.c b/src/backend/utils/fmgr/dfmgr.c
index 092004dcf3b..b03017f6275 100644
--- a/src/backend/utils/fmgr/dfmgr.c
+++ b/src/backend/utils/fmgr/dfmgr.c
@@ -79,7 +79,6 @@ char *Dynamic_library_path;
static void *internal_load_library(const char *libname);
static void incompatible_module_error(const char *libname,
const Pg_magic_struct *module_magic_data) pg_attribute_noreturn();
-static char *expand_dynamic_library_name(const char *name);
static void check_restricted_library_name(const char *name);
static char *substitute_libpath_macro(const char *name);
static char *find_in_dynamic_libpath(const char *basename);
@@ -410,7 +409,7 @@ incompatible_module_error(const char *libname,
*
* The result will always be freshly palloc'd.
*/
-static char *
+char *
expand_dynamic_library_name(const char *name)
{
bool have_slash;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e2734475189..4cd40ca9678 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -4654,6 +4654,12 @@ AlterSystemSetConfigFile(AlterSystemStmt *altersysstmt)
union config_var_val newval;
void *newextra = NULL;
+ /*
+ * PGC_S_FILE is used even though we should use PGC_S_TEST,
+ * since various GUC validation functions use TEST to give a
+ * NOTICE rather than an ERROR, and we don't want to allow
+ * setting values that would always return an error later.
+ */
if (!parse_and_validate_value(record, name, value,
PGC_S_FILE, ERROR,
&newval, &newextra))
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 630ed0f1629..6c424be4c47 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -4237,7 +4237,7 @@ struct config_string ConfigureNamesString[] =
},
&session_preload_libraries_string,
"",
- NULL, NULL, NULL
+ check_session_preload_libraries, NULL, NULL
},
{
@@ -4248,7 +4248,7 @@ struct config_string ConfigureNamesString[] =
},
&shared_preload_libraries_string,
"",
- NULL, NULL, NULL
+ check_shared_preload_libraries, NULL, NULL
},
{
@@ -4259,7 +4259,7 @@ struct config_string ConfigureNamesString[] =
},
&local_preload_libraries_string,
"",
- NULL, NULL, NULL
+ check_local_preload_libraries, NULL, NULL
},
{
diff --git a/src/include/fmgr.h b/src/include/fmgr.h
index ccb4070a251..c6319782a99 100644
--- a/src/include/fmgr.h
+++ b/src/include/fmgr.h
@@ -749,6 +749,7 @@ extern void **find_rendezvous_variable(const char *varName);
extern Size EstimateLibraryStateSpace(void);
extern void SerializeLibraryState(Size maxsize, char *start_address);
extern void RestoreLibraryState(char *start_address);
+char *expand_dynamic_library_name(const char *name);
/*
* Support for aggregate functions
diff --git a/src/include/utils/guc_hooks.h b/src/include/utils/guc_hooks.h
index 153c652c93e..a11c5488041 100644
--- a/src/include/utils/guc_hooks.h
+++ b/src/include/utils/guc_hooks.h
@@ -172,4 +172,11 @@ extern bool check_synchronized_standby_slots(char **newval, void **extra,
GucSource source);
extern void assign_synchronized_standby_slots(const char *newval, void *extra);
+extern bool check_local_preload_libraries(char **newval, void **extra,
+ GucSource source);
+extern bool check_session_preload_libraries(char **newval, void **extra,
+ GucSource source);
+extern bool check_shared_preload_libraries(char **newval, void **extra,
+ GucSource source);
+
#endif /* GUC_HOOKS_H */
diff --git a/src/test/modules/unsafe_tests/expected/rolenames.out b/src/test/modules/unsafe_tests/expected/rolenames.out
index 61396b2a805..de707a4803e 100644
--- a/src/test/modules/unsafe_tests/expected/rolenames.out
+++ b/src/test/modules/unsafe_tests/expected/rolenames.out
@@ -1083,6 +1083,25 @@ RESET SESSION AUTHORIZATION;
ERROR: current transaction is aborted, commands ignored until end of transaction block
ROLLBACK;
REVOKE pg_read_all_settings FROM regress_role_haspriv;
+-- test some warnings
+ALTER ROLE regress_testrol0 SET session_preload_libraries="DoesNotExist";
+WARNING: could not access file "DoesNotExist"
+DETAIL: New sessions will fail to connect with the new setting.
+ALTER ROLE regress_testrol0 SET local_preload_libraries="DoesNotExist";
+WARNING: could not access file "$libdir/plugins/DoesNotExist"
+DETAIL: New sessions will fail to connect with the new setting.
+CREATE DATABASE regression_nosuch_db;
+ALTER DATABASE regression_nosuch_db SET session_preload_libraries="DoesNotExist";
+WARNING: could not access file "DoesNotExist"
+DETAIL: New sessions will fail to connect with the new setting.
+ALTER DATABASE regression_nosuch_db SET local_preload_libraries="DoesNotExist";
+WARNING: could not access file "$libdir/plugins/DoesNotExist"
+DETAIL: New sessions will fail to connect with the new setting.
+DROP DATABASE regression_nosuch_db;
+-- SET doesn't do anything, but should not warn, either
+SET session_preload_libraries="DoesNotExist";
+SET SESSION session_preload_libraries="DoesNotExist";
+begin; SET LOCAL session_preload_libraries="DoesNotExist"; rollback;
-- clean up
\c
DROP SCHEMA test_roles_schema;
diff --git a/src/test/modules/unsafe_tests/sql/rolenames.sql b/src/test/modules/unsafe_tests/sql/rolenames.sql
index adac36536db..56fb52d4e08 100644
--- a/src/test/modules/unsafe_tests/sql/rolenames.sql
+++ b/src/test/modules/unsafe_tests/sql/rolenames.sql
@@ -494,6 +494,19 @@ RESET SESSION AUTHORIZATION;
ROLLBACK;
REVOKE pg_read_all_settings FROM regress_role_haspriv;
+-- test some warnings
+ALTER ROLE regress_testrol0 SET session_preload_libraries="DoesNotExist";
+ALTER ROLE regress_testrol0 SET local_preload_libraries="DoesNotExist";
+CREATE DATABASE regression_nosuch_db;
+ALTER DATABASE regression_nosuch_db SET session_preload_libraries="DoesNotExist";
+ALTER DATABASE regression_nosuch_db SET local_preload_libraries="DoesNotExist";
+DROP DATABASE regression_nosuch_db;
+
+-- SET doesn't do anything, but should not warn, either
+SET session_preload_libraries="DoesNotExist";
+SET SESSION session_preload_libraries="DoesNotExist";
+begin; SET LOCAL session_preload_libraries="DoesNotExist"; rollback;
+
-- clean up
\c
--
2.42.0
--e3dHrZwCppoiYgqG
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="0003-errcontext-if-server-fails-to-start-due-to-library-G.patch"
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