1//===- Errno.cpp - errno support --------------------------------*- C++ -*-===//
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 implements the errno wrappers.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/Support/Errno.h"
14#include "llvm/Config/config.h"
15#include <cstring>
16
17#if HAVE_ERRNO_H
18#include <errno.h>
19#endif
20
21//===----------------------------------------------------------------------===//
22//=== WARNING: Implementation here must contain only TRULY operating system
23//===          independent code.
24//===----------------------------------------------------------------------===//
25
26namespace llvm {
27namespace sys {
28
29#if HAVE_ERRNO_H
30std::string StrError() {
31  return StrError(errno);
32}
33#endif  // HAVE_ERRNO_H
34
35std::string StrError(int errnum) {
36  std::string str;
37  if (errnum == 0)
38    return str;
39#if defined(HAVE_STRERROR_R) || HAVE_DECL_STRERROR_S
40  const int MaxErrStrLen = 2000;
41  char buffer[MaxErrStrLen];
42  buffer[0] = '\0';
43#endif
44
45#ifdef HAVE_STRERROR_R
46  // strerror_r is thread-safe.
47#if defined(__GLIBC__) && defined(_GNU_SOURCE)
48  // glibc defines its own incompatible version of strerror_r
49  // which may not use the buffer supplied.
50  str = strerror_r(errnum, buffer, MaxErrStrLen - 1);
51#else
52  strerror_r(errnum, buffer, MaxErrStrLen - 1);
53  str = buffer;
54#endif
55#elif HAVE_DECL_STRERROR_S // "Windows Secure API"
56  strerror_s(buffer, MaxErrStrLen - 1, errnum);
57  str = buffer;
58#else
59  // Copy the thread un-safe result of strerror into
60  // the buffer as fast as possible to minimize impact
61  // of collision of strerror in multiple threads.
62  str = strerror(errnum);
63#endif
64  return str;
65}
66
67}  // namespace sys
68}  // namespace llvm
69