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policy.c
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/*-------------------------------------------------------------------------
*
* policy.c
* Commands for manipulating policies.
*
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/backend/commands/policy.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/htup.h"
#include "access/htup_details.h"
#include "access/relation.h"
#include "access/sysattr.h"
#include "access/table.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_policy.h"
#include "catalog/pg_type.h"
#include "commands/policy.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/pg_list.h"
#include "parser/parse_clause.h"
#include "parser/parse_collate.h"
#include "parser/parse_node.h"
#include "parser/parse_relation.h"
#include "rewrite/rewriteManip.h"
#include "rewrite/rowsecurity.h"
#include "storage/lock.h"
#include "utils/acl.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/syscache.h"
static void RangeVarCallbackForPolicy(const RangeVar *rv,
Oid relid, Oid oldrelid, void *arg);
static char parse_policy_command(const char *cmd_name);
static Datum *policy_role_list_to_array(List *roles, int *num_roles);
/*
* Callback to RangeVarGetRelidExtended().
*
* Checks the following:
* - the relation specified is a table.
* - current user owns the table.
* - the table is not a system table.
*
* If any of these checks fails then an error is raised.
*/
static void
RangeVarCallbackForPolicy(const RangeVar *rv, Oid relid, Oid oldrelid,
void *arg)
{
HeapTuple tuple;
Form_pg_class classform;
char relkind;
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(tuple))
return;
classform = (Form_pg_class) GETSTRUCT(tuple);
relkind = classform->relkind;
/* Must own relation. */
if (!pg_class_ownercheck(relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(get_rel_relkind(relid)), rv->relname);
/* No system table modifications unless explicitly allowed. */
if (!allowSystemTableMods && IsSystemClass(relid, classform))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
rv->relname)));
/* Relation type MUST be a table. */
if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table", rv->relname)));
ReleaseSysCache(tuple);
}
/*
* parse_policy_command -
* helper function to convert full command strings to their char
* representation.
*
* cmd_name - full string command name. Valid values are 'all', 'select',
* 'insert', 'update' and 'delete'.
*
*/
static char
parse_policy_command(const char *cmd_name)
{
char polcmd;
if (!cmd_name)
elog(ERROR, "unrecognized policy command");
if (strcmp(cmd_name, "all") == 0)
polcmd = '*';
else if (strcmp(cmd_name, "select") == 0)
polcmd = ACL_SELECT_CHR;
else if (strcmp(cmd_name, "insert") == 0)
polcmd = ACL_INSERT_CHR;
else if (strcmp(cmd_name, "update") == 0)
polcmd = ACL_UPDATE_CHR;
else if (strcmp(cmd_name, "delete") == 0)
polcmd = ACL_DELETE_CHR;
else
elog(ERROR, "unrecognized policy command");
return polcmd;
}
/*
* policy_role_list_to_array
* helper function to convert a list of RoleSpecs to an array of
* role id Datums.
*/
static Datum *
policy_role_list_to_array(List *roles, int *num_roles)
{
Datum *role_oids;
ListCell *cell;
int i = 0;
/* Handle no roles being passed in as being for public */
if (roles == NIL)
{
*num_roles = 1;
role_oids = (Datum *) palloc(*num_roles * sizeof(Datum));
role_oids[0] = ObjectIdGetDatum(ACL_ID_PUBLIC);
return role_oids;
}
*num_roles = list_length(roles);
role_oids = (Datum *) palloc(*num_roles * sizeof(Datum));
foreach(cell, roles)
{
RoleSpec *spec = lfirst(cell);
/*
* PUBLIC covers all roles, so it only makes sense alone.
*/
if (spec->roletype == ROLESPEC_PUBLIC)
{
if (*num_roles != 1)
{
ereport(WARNING,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("ignoring specified roles other than PUBLIC"),
errhint("All roles are members of the PUBLIC role.")));
*num_roles = 1;
}
role_oids[0] = ObjectIdGetDatum(ACL_ID_PUBLIC);
return role_oids;
}
else
role_oids[i++] =
ObjectIdGetDatum(get_rolespec_oid(spec, false));
}
return role_oids;
}
/*
* Load row security policy from the catalog, and store it in
* the relation's relcache entry.
*/
void
RelationBuildRowSecurity(Relation relation)
{
MemoryContext rscxt;
MemoryContext oldcxt = CurrentMemoryContext;
RowSecurityDesc *volatile rsdesc = NULL;
/*
* Create a memory context to hold everything associated with this
* relation's row security policy. This makes it easy to clean up during
* a relcache flush.
*/
rscxt = AllocSetContextCreate(CacheMemoryContext,
"row security descriptor",
ALLOCSET_SMALL_SIZES);
/*
* Since rscxt lives under CacheMemoryContext, it is long-lived. Use a
* PG_TRY block to ensure it'll get freed if we fail partway through.
*/
PG_TRY();
{
Relation catalog;
ScanKeyData skey;
SysScanDesc sscan;
HeapTuple tuple;
MemoryContextCopyAndSetIdentifier(rscxt,
RelationGetRelationName(relation));
rsdesc = MemoryContextAllocZero(rscxt, sizeof(RowSecurityDesc));
rsdesc->rscxt = rscxt;
catalog = table_open(PolicyRelationId, AccessShareLock);
ScanKeyInit(&skey,
Anum_pg_policy_polrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
sscan = systable_beginscan(catalog, PolicyPolrelidPolnameIndexId, true,
NULL, 1, &skey);
/*
* Loop through the row level security policies for this relation, if
* any.
*/
while (HeapTupleIsValid(tuple = systable_getnext(sscan)))
{
Datum value_datum;
char cmd_value;
bool permissive_value;
Datum roles_datum;
char *qual_value;
Expr *qual_expr;
char *with_check_value;
Expr *with_check_qual;
char *policy_name_value;
bool isnull;
RowSecurityPolicy *policy;
/*
* Note: all the pass-by-reference data we collect here is either
* still stored in the tuple, or constructed in the caller's
* short-lived memory context. We must copy it into rscxt
* explicitly below.
*/
/* Get policy command */
value_datum = heap_getattr(tuple, Anum_pg_policy_polcmd,
RelationGetDescr(catalog), &isnull);
Assert(!isnull);
cmd_value = DatumGetChar(value_datum);
/* Get policy permissive or restrictive */
value_datum = heap_getattr(tuple, Anum_pg_policy_polpermissive,
RelationGetDescr(catalog), &isnull);
Assert(!isnull);
permissive_value = DatumGetBool(value_datum);
/* Get policy name */
value_datum = heap_getattr(tuple, Anum_pg_policy_polname,
RelationGetDescr(catalog), &isnull);
Assert(!isnull);
policy_name_value = NameStr(*(DatumGetName(value_datum)));
/* Get policy roles */
roles_datum = heap_getattr(tuple, Anum_pg_policy_polroles,
RelationGetDescr(catalog), &isnull);
/* shouldn't be null, but initdb doesn't mark it so, so check */
if (isnull)
elog(ERROR, "unexpected null value in pg_policy.polroles");
/* Get policy qual */
value_datum = heap_getattr(tuple, Anum_pg_policy_polqual,
RelationGetDescr(catalog), &isnull);
if (!isnull)
{
qual_value = TextDatumGetCString(value_datum);
qual_expr = (Expr *) stringToNode(qual_value);
}
else
qual_expr = NULL;
/* Get WITH CHECK qual */
value_datum = heap_getattr(tuple, Anum_pg_policy_polwithcheck,
RelationGetDescr(catalog), &isnull);
if (!isnull)
{
with_check_value = TextDatumGetCString(value_datum);
with_check_qual = (Expr *) stringToNode(with_check_value);
}
else
with_check_qual = NULL;
/* Now copy everything into the cache context */
MemoryContextSwitchTo(rscxt);
policy = palloc0(sizeof(RowSecurityPolicy));
policy->policy_name = pstrdup(policy_name_value);
policy->polcmd = cmd_value;
policy->permissive = permissive_value;
policy->roles = DatumGetArrayTypePCopy(roles_datum);
policy->qual = copyObject(qual_expr);
policy->with_check_qual = copyObject(with_check_qual);
policy->hassublinks = checkExprHasSubLink((Node *) qual_expr) ||
checkExprHasSubLink((Node *) with_check_qual);
rsdesc->policies = lcons(policy, rsdesc->policies);
MemoryContextSwitchTo(oldcxt);
/* clean up some (not all) of the junk ... */
if (qual_expr != NULL)
pfree(qual_expr);
if (with_check_qual != NULL)
pfree(with_check_qual);
}
systable_endscan(sscan);
table_close(catalog, AccessShareLock);
}
PG_CATCH();
{
/* Delete rscxt, first making sure it isn't active */
MemoryContextSwitchTo(oldcxt);
MemoryContextDelete(rscxt);
PG_RE_THROW();
}
PG_END_TRY();
/* Success --- attach the policy descriptor to the relcache entry */
relation->rd_rsdesc = rsdesc;
}
/*
* RemovePolicyById -
* remove a policy by its OID. If a policy does not exist with the provided
* oid, then an error is raised.
*
* policy_id - the oid of the policy.
*/
void
RemovePolicyById(Oid policy_id)
{
Relation pg_policy_rel;
SysScanDesc sscan;
ScanKeyData skey[1];
HeapTuple tuple;
Oid relid;
Relation rel;
pg_policy_rel = table_open(PolicyRelationId, RowExclusiveLock);
/*
* Find the policy to delete.
*/
ScanKeyInit(&skey[0],
Anum_pg_policy_oid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(policy_id));
sscan = systable_beginscan(pg_policy_rel, PolicyOidIndexId, true,
NULL, 1, skey);
tuple = systable_getnext(sscan);
/* If the policy exists, then remove it, otherwise raise an error. */
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for policy %u", policy_id);
/*
* Open and exclusive-lock the relation the policy belongs to. (We need
* exclusive lock to lock out queries that might otherwise depend on the
* set of policies the rel has; furthermore we've got to hold the lock
* till commit.)
*/
relid = ((Form_pg_policy) GETSTRUCT(tuple))->polrelid;
rel = table_open(relid, AccessExclusiveLock);
if (rel->rd_rel->relkind != RELKIND_RELATION &&
rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
RelationGetRelationName(rel))));
if (!allowSystemTableMods && IsSystemRelation(rel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(rel))));
CatalogTupleDelete(pg_policy_rel, &tuple->t_self);
systable_endscan(sscan);
/*
* Note that, unlike some of the other flags in pg_class, relrowsecurity
* is not just an indication of if policies exist. When relrowsecurity is
* set by a user, then all access to the relation must be through a
* policy. If no policy is defined for the relation then a default-deny
* policy is created and all records are filtered (except for queries from
* the owner).
*/
CacheInvalidateRelcache(rel);
table_close(rel, NoLock);
/* Clean up */
table_close(pg_policy_rel, RowExclusiveLock);
}
/*
* RemoveRoleFromObjectPolicy -
* remove a role from a policy by its OID. If the role is not a member of
* the policy then an error is raised. False is returned to indicate that
* the role could not be removed due to being the only role on the policy
* and therefore the entire policy should be removed.
*
* Note that a warning will be thrown and true will be returned on a
* permission error, as the policy should not be removed in that case.
*
* roleid - the oid of the role to remove
* classid - should always be PolicyRelationId
* policy_id - the oid of the policy.
*/
bool
RemoveRoleFromObjectPolicy(Oid roleid, Oid classid, Oid policy_id)
{
Relation pg_policy_rel;
SysScanDesc sscan;
ScanKeyData skey[1];
HeapTuple tuple;
Oid relid;
Relation rel;
ArrayType *policy_roles;
int num_roles;
Datum roles_datum;
bool attr_isnull;
bool noperm = true;
Assert(classid == PolicyRelationId);
pg_policy_rel = table_open(PolicyRelationId, RowExclusiveLock);
/*
* Find the policy to update.
*/
ScanKeyInit(&skey[0],
Anum_pg_policy_oid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(policy_id));
sscan = systable_beginscan(pg_policy_rel, PolicyOidIndexId, true,
NULL, 1, skey);
tuple = systable_getnext(sscan);
/* Raise an error if we don't find the policy. */
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for policy %u", policy_id);
/*
* Open and exclusive-lock the relation the policy belongs to.
*/
relid = ((Form_pg_policy) GETSTRUCT(tuple))->polrelid;
rel = relation_open(relid, AccessExclusiveLock);
if (rel->rd_rel->relkind != RELKIND_RELATION &&
rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
RelationGetRelationName(rel))));
if (!allowSystemTableMods && IsSystemRelation(rel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(rel))));
/* Get the current set of roles */
roles_datum = heap_getattr(tuple,
Anum_pg_policy_polroles,
RelationGetDescr(pg_policy_rel),
&attr_isnull);
Assert(!attr_isnull);
policy_roles = DatumGetArrayTypePCopy(roles_datum);
/* We should be removing exactly one entry from the roles array */
num_roles = ARR_DIMS(policy_roles)[0] - 1;
Assert(num_roles >= 0);
/* Must own relation. */
if (pg_class_ownercheck(relid, GetUserId()))
noperm = false; /* user is allowed to modify this policy */
else
ereport(WARNING,
(errcode(ERRCODE_WARNING_PRIVILEGE_NOT_REVOKED),
errmsg("role \"%s\" could not be removed from policy \"%s\" on \"%s\"",
GetUserNameFromId(roleid, false),
NameStr(((Form_pg_policy) GETSTRUCT(tuple))->polname),
RelationGetRelationName(rel))));
/*
* If multiple roles exist on this policy, then remove the one we were
* asked to and leave the rest.
*/
if (!noperm && num_roles > 0)
{
int i,
j;
Oid *roles = (Oid *) ARR_DATA_PTR(policy_roles);
Datum *role_oids;
char *qual_value;
Node *qual_expr;
List *qual_parse_rtable = NIL;
char *with_check_value;
Node *with_check_qual;
List *with_check_parse_rtable = NIL;
Datum values[Natts_pg_policy];
bool isnull[Natts_pg_policy];
bool replaces[Natts_pg_policy];
Datum value_datum;
ArrayType *role_ids;
HeapTuple new_tuple;
ObjectAddress target;
ObjectAddress myself;
/* zero-clear */
memset(values, 0, sizeof(values));
memset(replaces, 0, sizeof(replaces));
memset(isnull, 0, sizeof(isnull));
/*
* All of the dependencies will be removed from the policy and then
* re-added. In order to get them correct, we need to extract out the
* expressions in the policy and construct a parsestate just enough to
* build the range table(s) to then pass to recordDependencyOnExpr().
*/
/* Get policy qual, to update dependencies */
value_datum = heap_getattr(tuple, Anum_pg_policy_polqual,
RelationGetDescr(pg_policy_rel), &attr_isnull);
if (!attr_isnull)
{
ParseState *qual_pstate;
/* parsestate is built just to build the range table */
qual_pstate = make_parsestate(NULL);
qual_value = TextDatumGetCString(value_datum);
qual_expr = stringToNode(qual_value);
/* Add this rel to the parsestate's rangetable, for dependencies */
(void) addRangeTableEntryForRelation(qual_pstate, rel,
AccessShareLock,
NULL, false, false);
qual_parse_rtable = qual_pstate->p_rtable;
free_parsestate(qual_pstate);
}
else
qual_expr = NULL;
/* Get WITH CHECK qual, to update dependencies */
value_datum = heap_getattr(tuple, Anum_pg_policy_polwithcheck,
RelationGetDescr(pg_policy_rel), &attr_isnull);
if (!attr_isnull)
{
ParseState *with_check_pstate;
/* parsestate is built just to build the range table */
with_check_pstate = make_parsestate(NULL);
with_check_value = TextDatumGetCString(value_datum);
with_check_qual = stringToNode(with_check_value);
/* Add this rel to the parsestate's rangetable, for dependencies */
(void) addRangeTableEntryForRelation(with_check_pstate, rel,
AccessShareLock,
NULL, false, false);
with_check_parse_rtable = with_check_pstate->p_rtable;
free_parsestate(with_check_pstate);
}
else
with_check_qual = NULL;
/* Rebuild the roles array to then update the pg_policy tuple with */
role_oids = (Datum *) palloc(num_roles * sizeof(Datum));
for (i = 0, j = 0; i < ARR_DIMS(policy_roles)[0]; i++)
/* Copy over all of the roles which are not the one being removed */
if (roles[i] != roleid)
role_oids[j++] = ObjectIdGetDatum(roles[i]);
/* We should have only removed the one role */
Assert(j == num_roles);
/* This is the array for the new tuple */
role_ids = construct_array(role_oids, num_roles, OIDOID,
sizeof(Oid), true, TYPALIGN_INT);
replaces[Anum_pg_policy_polroles - 1] = true;
values[Anum_pg_policy_polroles - 1] = PointerGetDatum(role_ids);
new_tuple = heap_modify_tuple(tuple,
RelationGetDescr(pg_policy_rel),
values, isnull, replaces);
CatalogTupleUpdate(pg_policy_rel, &new_tuple->t_self, new_tuple);
/* Remove all old dependencies. */
deleteDependencyRecordsFor(PolicyRelationId, policy_id, false);
/* Record the new set of dependencies */
target.classId = RelationRelationId;
target.objectId = relid;
target.objectSubId = 0;
myself.classId = PolicyRelationId;
myself.objectId = policy_id;
myself.objectSubId = 0;
recordDependencyOn(&myself, &target, DEPENDENCY_AUTO);
if (qual_expr)
recordDependencyOnExpr(&myself, qual_expr, qual_parse_rtable,
DEPENDENCY_NORMAL);
if (with_check_qual)
recordDependencyOnExpr(&myself, with_check_qual,
with_check_parse_rtable,
DEPENDENCY_NORMAL);
/* Remove all the old shared dependencies (roles) */
deleteSharedDependencyRecordsFor(PolicyRelationId, policy_id, 0);
/* Record the new shared dependencies (roles) */
target.classId = AuthIdRelationId;
target.objectSubId = 0;
for (i = 0; i < num_roles; i++)
{
target.objectId = DatumGetObjectId(role_oids[i]);
/* no need for dependency on the public role */
if (target.objectId != ACL_ID_PUBLIC)
recordSharedDependencyOn(&myself, &target,
SHARED_DEPENDENCY_POLICY);
}
InvokeObjectPostAlterHook(PolicyRelationId, policy_id, 0);
heap_freetuple(new_tuple);
/* Invalidate Relation Cache */
CacheInvalidateRelcache(rel);
}
/* Clean up. */
systable_endscan(sscan);
relation_close(rel, NoLock);
table_close(pg_policy_rel, RowExclusiveLock);
return (noperm || num_roles > 0);
}
/*
* CreatePolicy -
* handles the execution of the CREATE POLICY command.
*
* stmt - the CreatePolicyStmt that describes the policy to create.
*/
ObjectAddress
CreatePolicy(CreatePolicyStmt *stmt)
{
Relation pg_policy_rel;
Oid policy_id;
Relation target_table;
Oid table_id;
char polcmd;
Datum *role_oids;
int nitems = 0;
ArrayType *role_ids;
ParseState *qual_pstate;
ParseState *with_check_pstate;
ParseNamespaceItem *nsitem;
Node *qual;
Node *with_check_qual;
ScanKeyData skey[2];
SysScanDesc sscan;
HeapTuple policy_tuple;
Datum values[Natts_pg_policy];
bool isnull[Natts_pg_policy];
ObjectAddress target;
ObjectAddress myself;
int i;
/* Parse command */
polcmd = parse_policy_command(stmt->cmd_name);
/*
* If the command is SELECT or DELETE then WITH CHECK should be NULL.
*/
if ((polcmd == ACL_SELECT_CHR || polcmd == ACL_DELETE_CHR)
&& stmt->with_check != NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("WITH CHECK cannot be applied to SELECT or DELETE")));
/*
* If the command is INSERT then WITH CHECK should be the only expression
* provided.
*/
if (polcmd == ACL_INSERT_CHR && stmt->qual != NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("only WITH CHECK expression allowed for INSERT")));
/* Collect role ids */
role_oids = policy_role_list_to_array(stmt->roles, &nitems);
role_ids = construct_array(role_oids, nitems, OIDOID,
sizeof(Oid), true, TYPALIGN_INT);
/* Parse the supplied clause */
qual_pstate = make_parsestate(NULL);
with_check_pstate = make_parsestate(NULL);
/* zero-clear */
memset(values, 0, sizeof(values));
memset(isnull, 0, sizeof(isnull));
/* Get id of table. Also handles permissions checks. */
table_id = RangeVarGetRelidExtended(stmt->table, AccessExclusiveLock,
0,
RangeVarCallbackForPolicy,
(void *) stmt);
/* Open target_table to build quals. No additional lock is necessary. */
target_table = relation_open(table_id, NoLock);
/* Add for the regular security quals */
nsitem = addRangeTableEntryForRelation(qual_pstate, target_table,
AccessShareLock,
NULL, false, false);
addNSItemToQuery(qual_pstate, nsitem, false, true, true);
/* Add for the with-check quals */
nsitem = addRangeTableEntryForRelation(with_check_pstate, target_table,
AccessShareLock,
NULL, false, false);
addNSItemToQuery(with_check_pstate, nsitem, false, true, true);
qual = transformWhereClause(qual_pstate,
copyObject(stmt->qual),
EXPR_KIND_POLICY,
"POLICY");
with_check_qual = transformWhereClause(with_check_pstate,
copyObject(stmt->with_check),
EXPR_KIND_POLICY,
"POLICY");
/* Fix up collation information */
assign_expr_collations(qual_pstate, qual);
assign_expr_collations(with_check_pstate, with_check_qual);
/* Open pg_policy catalog */
pg_policy_rel = table_open(PolicyRelationId, RowExclusiveLock);
/* Set key - policy's relation id. */
ScanKeyInit(&skey[0],
Anum_pg_policy_polrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(table_id));
/* Set key - policy's name. */
ScanKeyInit(&skey[1],
Anum_pg_policy_polname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(stmt->policy_name));
sscan = systable_beginscan(pg_policy_rel,
PolicyPolrelidPolnameIndexId, true, NULL, 2,
skey);
policy_tuple = systable_getnext(sscan);
/* Complain if the policy name already exists for the table */
if (HeapTupleIsValid(policy_tuple))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("policy \"%s\" for table \"%s\" already exists",
stmt->policy_name, RelationGetRelationName(target_table))));
policy_id = GetNewOidWithIndex(pg_policy_rel, PolicyOidIndexId,
Anum_pg_policy_oid);
values[Anum_pg_policy_oid - 1] = ObjectIdGetDatum(policy_id);
values[Anum_pg_policy_polrelid - 1] = ObjectIdGetDatum(table_id);
values[Anum_pg_policy_polname - 1] = DirectFunctionCall1(namein,
CStringGetDatum(stmt->policy_name));
values[Anum_pg_policy_polcmd - 1] = CharGetDatum(polcmd);
values[Anum_pg_policy_polpermissive - 1] = BoolGetDatum(stmt->permissive);
values[Anum_pg_policy_polroles - 1] = PointerGetDatum(role_ids);
/* Add qual if present. */
if (qual)
values[Anum_pg_policy_polqual - 1] = CStringGetTextDatum(nodeToString(qual));
else
isnull[Anum_pg_policy_polqual - 1] = true;
/* Add WITH CHECK qual if present */
if (with_check_qual)
values[Anum_pg_policy_polwithcheck - 1] = CStringGetTextDatum(nodeToString(with_check_qual));
else
isnull[Anum_pg_policy_polwithcheck - 1] = true;
policy_tuple = heap_form_tuple(RelationGetDescr(pg_policy_rel), values,
isnull);
CatalogTupleInsert(pg_policy_rel, policy_tuple);
/* Record Dependencies */
target.classId = RelationRelationId;
target.objectId = table_id;
target.objectSubId = 0;
myself.classId = PolicyRelationId;
myself.objectId = policy_id;
myself.objectSubId = 0;
recordDependencyOn(&myself, &target, DEPENDENCY_AUTO);
recordDependencyOnExpr(&myself, qual, qual_pstate->p_rtable,
DEPENDENCY_NORMAL);
recordDependencyOnExpr(&myself, with_check_qual,
with_check_pstate->p_rtable, DEPENDENCY_NORMAL);
/* Register role dependencies */
target.classId = AuthIdRelationId;
target.objectSubId = 0;
for (i = 0; i < nitems; i++)
{
target.objectId = DatumGetObjectId(role_oids[i]);
/* no dependency if public */
if (target.objectId != ACL_ID_PUBLIC)
recordSharedDependencyOn(&myself, &target,
SHARED_DEPENDENCY_POLICY);
}
InvokeObjectPostCreateHook(PolicyRelationId, policy_id, 0);
/* Invalidate Relation Cache */
CacheInvalidateRelcache(target_table);
/* Clean up. */
heap_freetuple(policy_tuple);
free_parsestate(qual_pstate);
free_parsestate(with_check_pstate);
systable_endscan(sscan);
relation_close(target_table, NoLock);
table_close(pg_policy_rel, RowExclusiveLock);
return myself;
}
/*
* AlterPolicy -
* handles the execution of the ALTER POLICY command.
*
* stmt - the AlterPolicyStmt that describes the policy and how to alter it.
*/
ObjectAddress
AlterPolicy(AlterPolicyStmt *stmt)
{
Relation pg_policy_rel;
Oid policy_id;
Relation target_table;
Oid table_id;
Datum *role_oids = NULL;
int nitems = 0;
ArrayType *role_ids = NULL;
List *qual_parse_rtable = NIL;
List *with_check_parse_rtable = NIL;
Node *qual = NULL;
Node *with_check_qual = NULL;
ScanKeyData skey[2];
SysScanDesc sscan;
HeapTuple policy_tuple;
HeapTuple new_tuple;
Datum values[Natts_pg_policy];
bool isnull[Natts_pg_policy];
bool replaces[Natts_pg_policy];
ObjectAddress target;
ObjectAddress myself;
Datum polcmd_datum;
char polcmd;
bool polcmd_isnull;
int i;
/* Parse role_ids */
if (stmt->roles != NULL)
{
role_oids = policy_role_list_to_array(stmt->roles, &nitems);
role_ids = construct_array(role_oids, nitems, OIDOID,
sizeof(Oid), true, TYPALIGN_INT);
}
/* Get id of table. Also handles permissions checks. */
table_id = RangeVarGetRelidExtended(stmt->table, AccessExclusiveLock,
0,
RangeVarCallbackForPolicy,
(void *) stmt);
target_table = relation_open(table_id, NoLock);
/* Parse the using policy clause */
if (stmt->qual)
{
ParseNamespaceItem *nsitem;
ParseState *qual_pstate = make_parsestate(NULL);
nsitem = addRangeTableEntryForRelation(qual_pstate, target_table,
AccessShareLock,
NULL, false, false);
addNSItemToQuery(qual_pstate, nsitem, false, true, true);
qual = transformWhereClause(qual_pstate, copyObject(stmt->qual),
EXPR_KIND_POLICY,
"POLICY");
/* Fix up collation information */
assign_expr_collations(qual_pstate, qual);
qual_parse_rtable = qual_pstate->p_rtable;
free_parsestate(qual_pstate);
}
/* Parse the with-check policy clause */
if (stmt->with_check)
{
ParseNamespaceItem *nsitem;
ParseState *with_check_pstate = make_parsestate(NULL);
nsitem = addRangeTableEntryForRelation(with_check_pstate, target_table,
AccessShareLock,
NULL, false, false);
addNSItemToQuery(with_check_pstate, nsitem, false, true, true);
with_check_qual = transformWhereClause(with_check_pstate,
copyObject(stmt->with_check),
EXPR_KIND_POLICY,
"POLICY");
/* Fix up collation information */
assign_expr_collations(with_check_pstate, with_check_qual);
with_check_parse_rtable = with_check_pstate->p_rtable;
free_parsestate(with_check_pstate);
}
/* zero-clear */
memset(values, 0, sizeof(values));
memset(replaces, 0, sizeof(replaces));
memset(isnull, 0, sizeof(isnull));
/* Find policy to update. */
pg_policy_rel = table_open(PolicyRelationId, RowExclusiveLock);
/* Set key - policy's relation id. */
ScanKeyInit(&skey[0],
Anum_pg_policy_polrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(table_id));
/* Set key - policy's name. */
ScanKeyInit(&skey[1],
Anum_pg_policy_polname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(stmt->policy_name));
sscan = systable_beginscan(pg_policy_rel,