Line data Source code
1 : /* 2 : * contrib/spi/insert_username.c 3 : * 4 : * insert user name in response to a trigger 5 : * usage: insert_username (column_name) 6 : */ 7 : #include "postgres.h" 8 : 9 : #include "access/htup_details.h" 10 : #include "catalog/pg_type.h" 11 : #include "commands/trigger.h" 12 : #include "executor/spi.h" 13 : #include "miscadmin.h" 14 : #include "utils/builtins.h" 15 : #include "utils/rel.h" 16 : 17 0 : PG_MODULE_MAGIC_EXT( 18 : .name = "insert_username", 19 : .version = PG_VERSION 20 : ); 21 : 22 0 : PG_FUNCTION_INFO_V1(insert_username); 23 : 24 : Datum 25 0 : insert_username(PG_FUNCTION_ARGS) 26 : { 27 0 : TriggerData *trigdata = (TriggerData *) fcinfo->context; 28 : Trigger *trigger; /* to get trigger name */ 29 : int nargs; /* # of arguments */ 30 : Datum newval; /* new value of column */ 31 : bool newnull; /* null flag */ 32 : char **args; /* arguments */ 33 : char *relname; /* triggered relation name */ 34 : Relation rel; /* triggered relation */ 35 0 : HeapTuple rettuple = NULL; 36 : TupleDesc tupdesc; /* tuple description */ 37 : int attnum; 38 : 39 : /* sanity checks from autoinc.c */ 40 0 : if (!CALLED_AS_TRIGGER(fcinfo)) 41 : /* internal error */ 42 0 : elog(ERROR, "insert_username: not fired by trigger manager"); 43 0 : if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event)) 44 : /* internal error */ 45 0 : elog(ERROR, "insert_username: must be fired for row"); 46 0 : if (!TRIGGER_FIRED_BEFORE(trigdata->tg_event)) 47 : /* internal error */ 48 0 : elog(ERROR, "insert_username: must be fired before event"); 49 : 50 0 : if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event)) 51 0 : rettuple = trigdata->tg_trigtuple; 52 0 : else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event)) 53 0 : rettuple = trigdata->tg_newtuple; 54 : else 55 : /* internal error */ 56 0 : elog(ERROR, "insert_username: cannot process DELETE events"); 57 : 58 0 : rel = trigdata->tg_relation; 59 0 : relname = SPI_getrelname(rel); 60 : 61 0 : trigger = trigdata->tg_trigger; 62 : 63 0 : nargs = trigger->tgnargs; 64 0 : if (nargs != 1) 65 : /* internal error */ 66 0 : elog(ERROR, "insert_username (%s): one argument was expected", relname); 67 : 68 0 : args = trigger->tgargs; 69 0 : tupdesc = rel->rd_att; 70 : 71 0 : attnum = SPI_fnumber(tupdesc, args[0]); 72 : 73 0 : if (attnum <= 0) 74 0 : ereport(ERROR, 75 : (errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION), 76 : errmsg("\"%s\" has no attribute \"%s\"", relname, args[0]))); 77 : 78 0 : if (SPI_gettypeid(tupdesc, attnum) != TEXTOID) 79 0 : ereport(ERROR, 80 : (errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION), 81 : errmsg("attribute \"%s\" of \"%s\" must be type TEXT", 82 : args[0], relname))); 83 : 84 : /* create fields containing name */ 85 0 : newval = CStringGetTextDatum(GetUserNameFromId(GetUserId(), false)); 86 0 : newnull = false; 87 : 88 : /* construct new tuple */ 89 0 : rettuple = heap_modify_tuple_by_cols(rettuple, tupdesc, 90 : 1, &attnum, &newval, &newnull); 91 : 92 0 : pfree(relname); 93 : 94 0 : return PointerGetDatum(rettuple); 95 : }