Thread

  1. [PATCH v5 5/5] Improve tab completion for ALTER SYSTEM RESET for non-superusers

    Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> — 2025-08-08T23:29:39Z

    Non-superusers can only use ALTER SYSTEM on variables they've
    explicitly been GRANTed access to, and can't read the data_directory
    setting or pg_settings.sourceline column, so the existing tab
    completion for ALTER SYSTEM isn't very useful for them.
    
    Instead, query pg_parameter_acl to show the variables they do have
    permission to set via ALTER SYSTEM.
    ---
     src/bin/psql/tab-complete.in.c | 19 ++++++++++++++++---
     1 file changed, 16 insertions(+), 3 deletions(-)
    
    diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
    index 60bba212f5e..aee939e98be 100644
    --- a/src/bin/psql/tab-complete.in.c
    +++ b/src/bin/psql/tab-complete.in.c
    @@ -1049,6 +1049,13 @@ static const SchemaQuery Query_for_trigger_of_table = {
     "           '[_%%\\\\]', '\\\\\\&') || '_postgresql.auto.conf' " \
     "   AND pg_catalog.lower(name) LIKE pg_catalog.lower('%s')"
     
    +#define Query_for_list_of_alter_system_granted_vars \
    +"SELECT pg_catalog.lower(parname) FROM pg_catalog.pg_parameter_acl " \
    +" WHERE EXISTS (SELECT FROM pg_catalog.aclexplode(paracl) " \
    +"                WHERE pg_has_role(current_role, grantee, 'usage') " \
    +"                  AND privilege_type = 'ALTER SYSTEM') " \
    +"   AND pg_catalog.lower(parname) LIKE pg_catalog.lower('%s')"
    +
     #define Query_for_list_of_set_vars \
     "SELECT pg_catalog.lower(name) FROM pg_catalog.pg_settings "\
     " WHERE context IN ('user', 'superuser') "\
    @@ -2632,10 +2639,16 @@ match_previous_words(int pattern_id,
     	else if (Matches("ALTER", "SYSTEM"))
     		COMPLETE_WITH("SET", "RESET");
     	else if (Matches("ALTER", "SYSTEM", "SET"))
    -		COMPLETE_WITH_QUERY_VERBATIM(Query_for_list_of_alter_system_set_vars);
    +		if (is_superuser())
    +			COMPLETE_WITH_QUERY_VERBATIM(Query_for_list_of_alter_system_set_vars);
    +		else
    +			COMPLETE_WITH_QUERY_VERBATIM(Query_for_list_of_alter_system_granted_vars);
     	else if (Matches("ALTER", "SYSTEM", "RESET"))
    -		COMPLETE_WITH_QUERY_VERBATIM_PLUS(Query_for_list_of_alter_system_reset_vars,
    -										  "ALL");
    +		if (is_superuser())
    +			COMPLETE_WITH_QUERY_VERBATIM_PLUS(Query_for_list_of_alter_system_reset_vars,
    +											  "ALL");
    +		else
    +			COMPLETE_WITH_QUERY_VERBATIM(Query_for_list_of_alter_system_granted_vars);
     	else if (Matches("ALTER", "SYSTEM", "SET", MatchAny))
     		COMPLETE_WITH("TO");
     	/* ALTER VIEW <name> */
    -- 
    2.50.1
    
    
    --=-=-=--