1 /*-------------------------------------------------------------------------
2 *
3 * conversioncmds.c
4 * conversion creation command support code
5 *
6 * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/commands/conversioncmds.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres.h"
16
17 #include "access/heapam.h"
18 #include "access/htup_details.h"
19 #include "catalog/dependency.h"
20 #include "catalog/indexing.h"
21 #include "catalog/pg_conversion.h"
22 #include "catalog/pg_conversion_fn.h"
23 #include "catalog/pg_type.h"
24 #include "commands/alter.h"
25 #include "commands/conversioncmds.h"
26 #include "mb/pg_wchar.h"
27 #include "miscadmin.h"
28 #include "parser/parse_func.h"
29 #include "utils/builtins.h"
30 #include "utils/lsyscache.h"
31 #include "utils/rel.h"
32 #include "utils/syscache.h"
33
34 /*
35 * CREATE CONVERSION
36 */
37 ObjectAddress
CreateConversionCommand(CreateConversionStmt * stmt)38 CreateConversionCommand(CreateConversionStmt *stmt)
39 {
40 Oid namespaceId;
41 char *conversion_name;
42 AclResult aclresult;
43 int from_encoding;
44 int to_encoding;
45 Oid funcoid;
46 const char *from_encoding_name = stmt->for_encoding_name;
47 const char *to_encoding_name = stmt->to_encoding_name;
48 List *func_name = stmt->func_name;
49 static const Oid funcargs[] = {INT4OID, INT4OID, CSTRINGOID, INTERNALOID, INT4OID};
50 char result[1];
51
52 /* Convert list of names to a name and namespace */
53 namespaceId = QualifiedNameGetCreationNamespace(stmt->conversion_name,
54 &conversion_name);
55
56 /* Check we have creation rights in target namespace */
57 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(), ACL_CREATE);
58 if (aclresult != ACLCHECK_OK)
59 aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
60 get_namespace_name(namespaceId));
61
62 /* Check the encoding names */
63 from_encoding = pg_char_to_encoding(from_encoding_name);
64 if (from_encoding < 0)
65 ereport(ERROR,
66 (errcode(ERRCODE_UNDEFINED_OBJECT),
67 errmsg("source encoding \"%s\" does not exist",
68 from_encoding_name)));
69
70 to_encoding = pg_char_to_encoding(to_encoding_name);
71 if (to_encoding < 0)
72 ereport(ERROR,
73 (errcode(ERRCODE_UNDEFINED_OBJECT),
74 errmsg("destination encoding \"%s\" does not exist",
75 to_encoding_name)));
76
77 /*
78 * Check the existence of the conversion function. Function name could be
79 * a qualified name.
80 */
81 funcoid = LookupFuncName(func_name, sizeof(funcargs) / sizeof(Oid),
82 funcargs, false);
83
84 /* Check it returns VOID, else it's probably the wrong function */
85 if (get_func_rettype(funcoid) != VOIDOID)
86 ereport(ERROR,
87 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
88 errmsg("encoding conversion function %s must return type %s",
89 NameListToString(func_name), "void")));
90
91 /* Check we have EXECUTE rights for the function */
92 aclresult = pg_proc_aclcheck(funcoid, GetUserId(), ACL_EXECUTE);
93 if (aclresult != ACLCHECK_OK)
94 aclcheck_error(aclresult, ACL_KIND_PROC,
95 NameListToString(func_name));
96
97 /*
98 * Check that the conversion function is suitable for the requested source
99 * and target encodings. We do that by calling the function with an empty
100 * string; the conversion function should throw an error if it can't
101 * perform the requested conversion.
102 */
103 OidFunctionCall5(funcoid,
104 Int32GetDatum(from_encoding),
105 Int32GetDatum(to_encoding),
106 CStringGetDatum(""),
107 CStringGetDatum(result),
108 Int32GetDatum(0));
109
110 /*
111 * All seem ok, go ahead (possible failure would be a duplicate conversion
112 * name)
113 */
114 return ConversionCreate(conversion_name, namespaceId, GetUserId(),
115 from_encoding, to_encoding, funcoid, stmt->def);
116 }
117