1//===- AutoConvert.cpp - Auto conversion between ASCII/EBCDIC -------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains functions used for auto conversion between
10// ASCII/EBCDIC codepages specific to z/OS.
11//
12//===----------------------------------------------------------------------===//
13
14#ifdef __MVS__
15
16#include "llvm/Support/AutoConvert.h"
17#include <cassert>
18#include <fcntl.h>
19#include <sys/stat.h>
20#include <unistd.h>
21
22static int savedStdHandleAutoConversionMode[3] = {-1, -1, -1};
23
24int disableAutoConversion(int FD) {
25  static const struct f_cnvrt Convert = {
26      SETCVTOFF, // cvtcmd
27      0,         // pccsid
28      0,         // fccsid
29  };
30
31  return fcntl(FD, F_CONTROL_CVT, &Convert);
32}
33
34int restoreStdHandleAutoConversion(int FD) {
35  assert(FD == STDIN_FILENO || FD == STDOUT_FILENO || FD == STDERR_FILENO);
36  if (savedStdHandleAutoConversionMode[FD] == -1)
37    return 0;
38  struct f_cnvrt Cvt = {
39      savedStdHandleAutoConversionMode[FD], // cvtcmd
40      0,                                    // pccsid
41      0,                                    // fccsid
42  };
43  return (fcntl(FD, F_CONTROL_CVT, &Cvt));
44}
45
46int enableAutoConversion(int FD) {
47  struct f_cnvrt Query = {
48      QUERYCVT, // cvtcmd
49      0,        // pccsid
50      0,        // fccsid
51  };
52
53  if (fcntl(FD, F_CONTROL_CVT, &Query) == -1)
54    return -1;
55
56  // We don't need conversion for UTF-8 tagged files.
57  // TODO: Remove the assumption of ISO8859-1 = UTF-8 here when we fully resolve
58  // problems related to UTF-8 tagged source files.
59  // When the pccsid is not ISO8859-1, autoconversion is still needed.
60  if (Query.pccsid == CCSID_ISO8859_1 &&
61      (Query.fccsid == CCSID_UTF_8 || Query.fccsid == CCSID_ISO8859_1))
62    return 0;
63
64  // Save the state of std handles before we make changes to it.
65  if ((FD == STDIN_FILENO || FD == STDOUT_FILENO || FD == STDERR_FILENO) &&
66      savedStdHandleAutoConversionMode[FD] == -1)
67    savedStdHandleAutoConversionMode[FD] = Query.cvtcmd;
68
69  if (FD == STDOUT_FILENO || FD == STDERR_FILENO)
70    Query.cvtcmd = SETCVTON;
71  else
72    Query.cvtcmd = SETCVTALL;
73
74  Query.pccsid =
75      (FD == STDIN_FILENO || FD == STDOUT_FILENO || FD == STDERR_FILENO)
76          ? 0
77          : CCSID_UTF_8;
78  // Assume untagged files to be IBM-1047 encoded.
79  Query.fccsid = (Query.fccsid == FT_UNTAGGED) ? CCSID_IBM_1047 : Query.fccsid;
80  return fcntl(FD, F_CONTROL_CVT, &Query);
81}
82
83std::error_code llvm::disableAutoConversion(int FD) {
84  if (::disableAutoConversion(FD) == -1)
85    return std::error_code(errno, std::generic_category());
86
87  return std::error_code();
88}
89
90std::error_code llvm::enableAutoConversion(int FD) {
91  if (::enableAutoConversion(FD) == -1)
92    return std::error_code(errno, std::generic_category());
93
94  return std::error_code();
95}
96
97std::error_code llvm::restoreStdHandleAutoConversion(int FD) {
98  if (::restoreStdHandleAutoConversion(FD) == -1)
99    return std::error_code(errno, std::generic_category());
100
101  return std::error_code();
102}
103
104std::error_code llvm::setFileTag(int FD, int CCSID, bool Text) {
105  assert((!Text || (CCSID != FT_UNTAGGED && CCSID != FT_BINARY)) &&
106         "FT_UNTAGGED and FT_BINARY are not allowed for text files");
107  struct file_tag Tag;
108  Tag.ft_ccsid = CCSID;
109  Tag.ft_txtflag = Text;
110  Tag.ft_deferred = 0;
111  Tag.ft_rsvflags = 0;
112
113  if (fcntl(FD, F_SETTAG, &Tag) == -1)
114    return std::error_code(errno, std::generic_category());
115  return std::error_code();
116}
117
118#endif // __MVS__
119