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1 : /*-------------------------------------------------------------------------
2 : *
3 : * proclang.c
4 : * PostgreSQL LANGUAGE support code.
5 : *
6 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : * IDENTIFICATION
10 : * src/backend/commands/proclang.c
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 : #include "postgres.h"
15 :
16 : #include "access/table.h"
17 : #include "catalog/catalog.h"
18 : #include "catalog/dependency.h"
19 : #include "catalog/indexing.h"
20 : #include "catalog/objectaccess.h"
21 : #include "catalog/pg_language.h"
22 : #include "catalog/pg_proc.h"
23 : #include "catalog/pg_type.h"
24 : #include "commands/proclang.h"
25 : #include "miscadmin.h"
26 : #include "parser/parse_func.h"
27 : #include "utils/builtins.h"
28 : #include "utils/lsyscache.h"
29 : #include "utils/rel.h"
30 : #include "utils/syscache.h"
31 :
32 :
33 : /*
34 : * CREATE LANGUAGE
35 : */
36 : ObjectAddress
37 140 : CreateProceduralLanguage(CreatePLangStmt *stmt)
38 : {
39 140 : const char *languageName = stmt->plname;
40 140 : Oid languageOwner = GetUserId();
41 : Oid handlerOid,
42 : inlineOid,
43 : valOid;
44 : Oid funcrettype;
45 : Oid funcargtypes[1];
46 : Relation rel;
47 : TupleDesc tupDesc;
48 : Datum values[Natts_pg_language];
49 : bool nulls[Natts_pg_language];
50 : bool replaces[Natts_pg_language];
51 : NameData langname;
52 : HeapTuple oldtup;
53 : HeapTuple tup;
54 : Oid langoid;
55 : bool is_update;
56 : ObjectAddress myself,
57 : referenced;
58 : ObjectAddresses *addrs;
59 :
60 : /*
61 : * Check permission
62 : */
63 140 : if (!superuser())
64 0 : ereport(ERROR,
65 : (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
66 : errmsg("must be superuser to create custom procedural language")));
67 :
68 : /*
69 : * Lookup the PL handler function and check that it is of the expected
70 : * return type
71 : */
72 : Assert(stmt->plhandler);
73 140 : handlerOid = LookupFuncName(stmt->plhandler, 0, NULL, false);
74 140 : funcrettype = get_func_rettype(handlerOid);
75 140 : if (funcrettype != LANGUAGE_HANDLEROID)
76 0 : ereport(ERROR,
77 : (errcode(ERRCODE_WRONG_OBJECT_TYPE),
78 : errmsg("function %s must return type %s",
79 : NameListToString(stmt->plhandler), "language_handler")));
80 :
81 : /* validate the inline function */
82 140 : if (stmt->plinline)
83 : {
84 122 : funcargtypes[0] = INTERNALOID;
85 122 : inlineOid = LookupFuncName(stmt->plinline, 1, funcargtypes, false);
86 : /* return value is ignored, so we don't check the type */
87 : }
88 : else
89 18 : inlineOid = InvalidOid;
90 :
91 : /* validate the validator function */
92 140 : if (stmt->plvalidator)
93 : {
94 122 : funcargtypes[0] = OIDOID;
95 122 : valOid = LookupFuncName(stmt->plvalidator, 1, funcargtypes, false);
96 : /* return value is ignored, so we don't check the type */
97 : }
98 : else
99 18 : valOid = InvalidOid;
100 :
101 : /* ok to create it */
102 140 : rel = table_open(LanguageRelationId, RowExclusiveLock);
103 140 : tupDesc = RelationGetDescr(rel);
104 :
105 : /* Prepare data to be inserted */
106 140 : memset(values, 0, sizeof(values));
107 140 : memset(nulls, false, sizeof(nulls));
108 140 : memset(replaces, true, sizeof(replaces));
109 :
110 140 : namestrcpy(&langname, languageName);
111 140 : values[Anum_pg_language_lanname - 1] = NameGetDatum(&langname);
112 140 : values[Anum_pg_language_lanowner - 1] = ObjectIdGetDatum(languageOwner);
113 140 : values[Anum_pg_language_lanispl - 1] = BoolGetDatum(true);
114 140 : values[Anum_pg_language_lanpltrusted - 1] = BoolGetDatum(stmt->pltrusted);
115 140 : values[Anum_pg_language_lanplcallfoid - 1] = ObjectIdGetDatum(handlerOid);
116 140 : values[Anum_pg_language_laninline - 1] = ObjectIdGetDatum(inlineOid);
117 140 : values[Anum_pg_language_lanvalidator - 1] = ObjectIdGetDatum(valOid);
118 140 : nulls[Anum_pg_language_lanacl - 1] = true;
119 :
120 : /* Check for pre-existing definition */
121 140 : oldtup = SearchSysCache1(LANGNAME, PointerGetDatum(languageName));
122 :
123 140 : if (HeapTupleIsValid(oldtup))
124 : {
125 0 : Form_pg_language oldform = (Form_pg_language) GETSTRUCT(oldtup);
126 :
127 : /* There is one; okay to replace it? */
128 0 : if (!stmt->replace)
129 0 : ereport(ERROR,
130 : (errcode(ERRCODE_DUPLICATE_OBJECT),
131 : errmsg("language \"%s\" already exists", languageName)));
132 :
133 : /* This is currently pointless, since we already checked superuser */
134 : #ifdef NOT_USED
135 : if (!object_ownercheck(LanguageRelationId, oldform->oid, languageOwner))
136 : aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_LANGUAGE,
137 : languageName);
138 : #endif
139 :
140 : /*
141 : * Do not change existing oid, ownership or permissions. Note
142 : * dependency-update code below has to agree with this decision.
143 : */
144 0 : replaces[Anum_pg_language_oid - 1] = false;
145 0 : replaces[Anum_pg_language_lanowner - 1] = false;
146 0 : replaces[Anum_pg_language_lanacl - 1] = false;
147 :
148 : /* Okay, do it... */
149 0 : tup = heap_modify_tuple(oldtup, tupDesc, values, nulls, replaces);
150 0 : CatalogTupleUpdate(rel, &tup->t_self, tup);
151 :
152 0 : langoid = oldform->oid;
153 0 : ReleaseSysCache(oldtup);
154 0 : is_update = true;
155 : }
156 : else
157 : {
158 : /* Creating a new language */
159 140 : langoid = GetNewOidWithIndex(rel, LanguageOidIndexId,
160 : Anum_pg_language_oid);
161 140 : values[Anum_pg_language_oid - 1] = ObjectIdGetDatum(langoid);
162 140 : tup = heap_form_tuple(tupDesc, values, nulls);
163 140 : CatalogTupleInsert(rel, tup);
164 140 : is_update = false;
165 : }
166 :
167 : /*
168 : * Create dependencies for the new language. If we are updating an
169 : * existing language, first delete any existing pg_depend entries.
170 : * (However, since we are not changing ownership or permissions, the
171 : * shared dependencies do *not* need to change, and we leave them alone.)
172 : */
173 140 : myself.classId = LanguageRelationId;
174 140 : myself.objectId = langoid;
175 140 : myself.objectSubId = 0;
176 :
177 140 : if (is_update)
178 0 : deleteDependencyRecordsFor(myself.classId, myself.objectId, true);
179 :
180 : /* dependency on owner of language */
181 140 : if (!is_update)
182 140 : recordDependencyOnOwner(myself.classId, myself.objectId,
183 : languageOwner);
184 :
185 : /* dependency on extension */
186 140 : recordDependencyOnCurrentExtension(&myself, is_update);
187 :
188 140 : addrs = new_object_addresses();
189 :
190 : /* dependency on the PL handler function */
191 140 : ObjectAddressSet(referenced, ProcedureRelationId, handlerOid);
192 140 : add_exact_object_address(&referenced, addrs);
193 :
194 : /* dependency on the inline handler function, if any */
195 140 : if (OidIsValid(inlineOid))
196 : {
197 122 : ObjectAddressSet(referenced, ProcedureRelationId, inlineOid);
198 122 : add_exact_object_address(&referenced, addrs);
199 : }
200 :
201 : /* dependency on the validator function, if any */
202 140 : if (OidIsValid(valOid))
203 : {
204 122 : ObjectAddressSet(referenced, ProcedureRelationId, valOid);
205 122 : add_exact_object_address(&referenced, addrs);
206 : }
207 :
208 140 : record_object_address_dependencies(&myself, addrs, DEPENDENCY_NORMAL);
209 140 : free_object_addresses(addrs);
210 :
211 : /* Post creation hook for new procedural language */
212 140 : InvokeObjectPostCreateHook(LanguageRelationId, myself.objectId, 0);
213 :
214 140 : table_close(rel, RowExclusiveLock);
215 :
216 140 : return myself;
217 : }
218 :
219 : /*
220 : * get_language_oid - given a language name, look up the OID
221 : *
222 : * If missing_ok is false, throw an error if language name not found. If
223 : * true, just return InvalidOid.
224 : */
225 : Oid
226 462 : get_language_oid(const char *langname, bool missing_ok)
227 : {
228 : Oid oid;
229 :
230 462 : oid = GetSysCacheOid1(LANGNAME, Anum_pg_language_oid,
231 : CStringGetDatum(langname));
232 462 : if (!OidIsValid(oid) && !missing_ok)
233 16 : ereport(ERROR,
234 : (errcode(ERRCODE_UNDEFINED_OBJECT),
235 : errmsg("language \"%s\" does not exist", langname)));
236 446 : return oid;
237 : }
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