hashvalidate.c

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/*-------------------------------------------------------------------------
 *
 * hashvalidate.c
 *    Opclass validator for hash.
 *
 * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/backend/access/hash/hashvalidate.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/amvalidate.h"
#include "access/hash.h"
#include "access/htup_details.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "parser/parse_coerce.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/syscache.h"


static bool check_hash_func_signature(Oid funcid, Oid restype, Oid argtype);


/*
 * Validator for a hash opclass.
 *
 * Some of the checks done here cover the whole opfamily, and therefore are
 * redundant when checking each opclass in a family.  But they don't run long
 * enough to be much of a problem, so we accept the duplication rather than
 * complicate the amvalidate API.
 */
bool
hashvalidate(Oid opclassoid)
{
    bool        result = true;
    HeapTuple   classtup;
    Form_pg_opclass classform;
    Oid         opfamilyoid;
    Oid         opcintype;
    char       *opclassname;
    HeapTuple   familytup;
    Form_pg_opfamily familyform;
    char       *opfamilyname;
    CatCList   *proclist,
               *oprlist;
    List       *grouplist;
    OpFamilyOpFuncGroup *opclassgroup;
    List       *hashabletypes = NIL;
    int         i;
    ListCell   *lc;

    /* Fetch opclass information */
    classtup = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclassoid));
    if (!HeapTupleIsValid(classtup))
        elog(ERROR, "cache lookup failed for operator class %u", opclassoid);
    classform = (Form_pg_opclass) GETSTRUCT(classtup);

    opfamilyoid = classform->opcfamily;
    opcintype = classform->opcintype;
    opclassname = NameStr(classform->opcname);

    /* Fetch opfamily information */
    familytup = SearchSysCache1(OPFAMILYOID, ObjectIdGetDatum(opfamilyoid));
    if (!HeapTupleIsValid(familytup))
        elog(ERROR, "cache lookup failed for operator family %u", opfamilyoid);
    familyform = (Form_pg_opfamily) GETSTRUCT(familytup);

    opfamilyname = NameStr(familyform->opfname);

    /* Fetch all operators and support functions of the opfamily */
    oprlist = SearchSysCacheList1(AMOPSTRATEGY, ObjectIdGetDatum(opfamilyoid));
    proclist = SearchSysCacheList1(AMPROCNUM, ObjectIdGetDatum(opfamilyoid));

    /* Check individual support functions */
    for (i = 0; i < proclist->n_members; i++)
    {
        HeapTuple   proctup = &proclist->members[i]->tuple;
        Form_pg_amproc procform = (Form_pg_amproc) GETSTRUCT(proctup);

        /*
         * All hash functions should be registered with matching left/right
         * types
         */
        if (procform->amproclefttype != procform->amprocrighttype)
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("hash opfamily %s contains support procedure %s with cross-type registration",
                            opfamilyname,
                            format_procedure(procform->amproc))));
            result = false;
        }

        /* Check procedure numbers and function signatures */
        switch (procform->amprocnum)
        {
            case HASHPROC:
                if (!check_hash_func_signature(procform->amproc, INT4OID,
                                               procform->amproclefttype))
                {
                    ereport(INFO,
                            (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                             errmsg("hash opfamily %s contains function %s with wrong signature for support number %d",
                                    opfamilyname,
                                    format_procedure(procform->amproc),
                                    procform->amprocnum)));
                    result = false;
                }
                else
                {
                    /* Remember which types we can hash */
                    hashabletypes =
                        list_append_unique_oid(hashabletypes,
                                               procform->amproclefttype);
                }
                break;
            default:
                ereport(INFO,
                        (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                         errmsg("hash opfamily %s contains function %s with invalid support number %d",
                                opfamilyname,
                                format_procedure(procform->amproc),
                                procform->amprocnum)));
                result = false;
                break;
        }
    }

    /* Check individual operators */
    for (i = 0; i < oprlist->n_members; i++)
    {
        HeapTuple   oprtup = &oprlist->members[i]->tuple;
        Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup);

        /* Check that only allowed strategy numbers exist */
        if (oprform->amopstrategy < 1 ||
            oprform->amopstrategy > HTMaxStrategyNumber)
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("hash opfamily %s contains operator %s with invalid strategy number %d",
                            opfamilyname,
                            format_operator(oprform->amopopr),
                            oprform->amopstrategy)));
            result = false;
        }

        /* hash doesn't support ORDER BY operators */
        if (oprform->amoppurpose != AMOP_SEARCH ||
            OidIsValid(oprform->amopsortfamily))
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("hash opfamily %s contains invalid ORDER BY specification for operator %s",
                            opfamilyname,
                            format_operator(oprform->amopopr))));
            result = false;
        }

        /* Check operator signature --- same for all hash strategies */
        if (!check_amop_signature(oprform->amopopr, BOOLOID,
                                  oprform->amoplefttype,
                                  oprform->amoprighttype))
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("hash opfamily %s contains operator %s with wrong signature",
                            opfamilyname,
                            format_operator(oprform->amopopr))));
            result = false;
        }

        /* There should be relevant hash procedures for each datatype */
        if (!list_member_oid(hashabletypes, oprform->amoplefttype) ||
            !list_member_oid(hashabletypes, oprform->amoprighttype))
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
            errmsg("hash opfamily %s lacks support function for operator %s",
                   opfamilyname,
                   format_operator(oprform->amopopr))));
            result = false;
        }
    }

    /* Now check for inconsistent groups of operators/functions */
    grouplist = identify_opfamily_groups(oprlist, proclist);
    opclassgroup = NULL;
    foreach(lc, grouplist)
    {
        OpFamilyOpFuncGroup *thisgroup = (OpFamilyOpFuncGroup *) lfirst(lc);

        /* Remember the group exactly matching the test opclass */
        if (thisgroup->lefttype == opcintype &&
            thisgroup->righttype == opcintype)
            opclassgroup = thisgroup;

        /*
         * Complain if there seems to be an incomplete set of operators for
         * this datatype pair (implying that we have a hash function but no
         * operator).
         */
        if (thisgroup->operatorset != (1 << HTEqualStrategyNumber))
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("hash opfamily %s is missing operator(s) for types %s and %s",
                            opfamilyname,
                            format_type_be(thisgroup->lefttype),
                            format_type_be(thisgroup->righttype))));
            result = false;
        }
    }

    /* Check that the originally-named opclass is supported */
    /* (if group is there, we already checked it adequately above) */
    if (!opclassgroup)
    {
        ereport(INFO,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("hash opclass %s is missing operator(s)",
                        opclassname)));
        result = false;
    }

    /*
     * Complain if the opfamily doesn't have entries for all possible
     * combinations of its supported datatypes.  While missing cross-type
     * operators are not fatal, it seems reasonable to insist that all
     * built-in hash opfamilies be complete.
     */
    if (list_length(grouplist) !=
        list_length(hashabletypes) * list_length(hashabletypes))
    {
        ereport(INFO,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("hash opfamily %s is missing cross-type operator(s)",
                        opfamilyname)));
        result = false;
    }

    ReleaseCatCacheList(proclist);
    ReleaseCatCacheList(oprlist);
    ReleaseSysCache(familytup);
    ReleaseSysCache(classtup);

    return result;
}


/*
 * We need a custom version of check_amproc_signature because of assorted
 * hacks in the core hash opclass definitions.
 */
static bool
check_hash_func_signature(Oid funcid, Oid restype, Oid argtype)
{
    bool        result = true;
    HeapTuple   tp;
    Form_pg_proc procform;

    tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
    if (!HeapTupleIsValid(tp))
        elog(ERROR, "cache lookup failed for function %u", funcid);
    procform = (Form_pg_proc) GETSTRUCT(tp);

    if (procform->prorettype != restype || procform->proretset ||
        procform->pronargs != 1)
        result = false;

    if (!IsBinaryCoercible(argtype, procform->proargtypes.values[0]))
    {
        /*
         * Some of the built-in hash opclasses cheat by using hash functions
         * that are different from but physically compatible with the opclass
         * datatype.  In some of these cases, even a "binary coercible" check
         * fails because there's no relevant cast.  For the moment, fix it by
         * having a whitelist of allowed cases.  Test the specific function
         * identity, not just its input type, because hashvarlena() takes
         * INTERNAL and allowing any such function seems too scary.
         */
        if (funcid == F_HASHINT4 &&
            (argtype == DATEOID ||
             argtype == ABSTIMEOID || argtype == RELTIMEOID ||
             argtype == XIDOID || argtype == CIDOID))
             /* okay, allowed use of hashint4() */ ;
        else if (funcid == F_TIMESTAMP_HASH &&
                 argtype == TIMESTAMPTZOID)
             /* okay, allowed use of timestamp_hash() */ ;
        else if (funcid == F_HASHCHAR &&
                 argtype == BOOLOID)
             /* okay, allowed use of hashchar() */ ;
        else if (funcid == F_HASHVARLENA &&
                 argtype == BYTEAOID)
             /* okay, allowed use of hashvarlena() */ ;
        else
            result = false;
    }

    ReleaseSysCache(tp);
    return result;
}