Switch to Win32Exception(GetLastWin32Error)

This is verified to work "correctly" on Linux in that it gets the
`perror` for the last set value of errno in native code.

No extra mapping or handling needs to be done on our part.

Keeping the strerror_r implementation in the history for the valuable
implementation of config.h.in in the library.

src/System.Management.Automation/CoreCLR/CorePsPlatform.cs

@@ -4,6 +4,7 @@ Copyright (c) Microsoft Corporation.  All rights reserved.
 
 using System.Collections.Generic;
 using System.Runtime.InteropServices;
+using System.ComponentModel;
 using Microsoft.Win32;
 using Microsoft.Win32.SafeHandles;
 using System.IO;
@@ -451,13 +452,15 @@ namespace System.Management.Automation
             return 0;
         }
 
+        // Unix specific implementations of required functionality
+        //
+        // Please note that `Win32Exception(Marshal.GetLastWin32Error())`
+        // works *correctly* on Linux in that it creates an exception with
+        // the string perror would give you for the last set value of errno.
+        // No manual mapping is required. .NET Core maps the Linux errno
+        // to a PAL value and calls strerror_r underneath to generate the message.
         internal static class Unix
         {
-            internal static string GetLastPerror()
-            {
-                return Unix.NativeMethods.GetStrError(Marshal.GetLastWin32Error());
-            }
-
             private static string s_userName;
             public static string UserName
             {
@@ -513,8 +516,7 @@ namespace System.Management.Automation
                 }
                 else
                 {
-                    int lastError = Marshal.GetLastWin32Error();
-                    throw new InvalidOperationException("Unix.IsHardLink error: " + lastError);
+                    throw new Win32Exception(Marshal.GetLastWin32Error());
                 }
             }
 
@@ -523,8 +525,7 @@ namespace System.Management.Automation
                 int ret = NativeMethods.SetDate(info);
                 if (ret == -1)
                 {
-                    int lastError = Marshal.GetLastWin32Error();
-                    throw new InvalidOperationException("Unix.NonWindowsSetDate error: " + lastError);
+                    throw new Win32Exception(Marshal.GetLastWin32Error());
                 }
             }
 
@@ -573,10 +574,6 @@ namespace System.Management.Automation
 
                 // C bools are 1 byte and so must be marshaled as I1
 
-                [DllImport(psLib, CharSet = CharSet.Ansi)]
-                [return: MarshalAs(UnmanagedType.LPStr)]
-                internal static extern string GetStrError(int errno);
-
                 [DllImport(psLib, CharSet = CharSet.Ansi, SetLastError = true)]
                 [return: MarshalAs(UnmanagedType.LPStr)]
                 internal static extern string GetUserName();

src/System.Management.Automation/namespaces/FileSystemProvider.cs

@@ -2231,6 +2231,7 @@ namespace Microsoft.PowerShell.Commands
 
                     if (!success)
                     {
+                        // Porting note: The Win32Exception will report the correct error on Linux
                         int errorCode = Marshal.GetLastWin32Error();
 
                         Win32Exception w32Exception = new Win32Exception((int)errorCode);

src/libpsl-native/.gitignore

@@ -9,5 +9,4 @@ Testing/
 test/psl-native-test
 src/libpsl-native.so
 src/libpsl-native.dylib
-src/config.h
 test/native-tests.xml

src/libpsl-native/src/CMakeLists.txt

@@ -1,18 +1,3 @@
-include(CheckCXXSourceCompiles)
-check_cxx_source_compiles(
-    "
-    #include <string.h>
-    int main()
-    {
-        char buffer[1];
-        char* c = strerror_r(0, buffer, 0);
-        (void)c;
-    }
-    "
-    HAVE_GNU_STRERROR_R)
-
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/config.h.in ${CMAKE_CURRENT_BINARY_DIR}/config.h)
-
 add_library(psl-native SHARED
   getstat.cpp
   getlstat.cpp
@@ -24,7 +9,6 @@ add_library(psl-native SHARED
   getcomputername.cpp
   getlinkcount.cpp
   getfullyqualifiedname.cpp
-  getstrerror.cpp
   isfile.cpp
   isdirectory.cpp
   issymlink.cpp

src/libpsl-native/src/config.h.in

@@ -1 +0,0 @@
-#cmakedefine HAVE_GNU_STRERROR_R 1

src/libpsl-native/src/getstrerror.cpp

@@ -1,40 +0,0 @@
-#include "getstrerror.h"
-
-#include <assert.h>
-#include <sys/types.h>
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-char* GetStrError(int errnum)
-{
-    size_t buflen = 256;
-    char* buf = (char*)calloc(buflen, sizeof(char));
-
-// Note that we must use strerror_r because plain strerror is not
-// thread-safe.
-//
-// However, there are two versions of strerror_r:
-//    - GNU:   char* strerror_r(int, char*, size_t);
-//    - POSIX: int   strerror_r(int, char*, size_t);
-//
-// The former may or may not use the supplied buffer, and returns
-// the error message string. The latter stores the error message
-// string into the supplied buffer and returns an error code.
-
-#if HAVE_GNU_STRERROR_R
-    const char* ret = strerror_r(errnum, buf, buflen);
-    assert(ret != NULL);
-    if (ret != buf)
-    {
-        // message was returned but is static, copy for return
-        strncpy(buf, ret, buflen);
-    }
-#else
-    int ret = strerror_r(errnum, buf, buflen);
-    // EINVAL: unknown error but reasonable message returned.
-    // ERANGE: too small for entire message, but still filled and null-terminated.
-    assert(ret == 0 || ret == EINVAL || ret == ERANGE);
-#endif
-    return buf;
-}

src/libpsl-native/src/getstrerror.h

@@ -1,9 +0,0 @@
-#pragma once
-
-#include "pal.h"
-
-PAL_BEGIN_EXTERNC
-
-char* GetStrError(int);
-
-PAL_END_EXTERNC

src/libpsl-native/src/pal.h

@@ -1,7 +1,5 @@
 #pragma once
 
-#include "config.h"
-
 #include <stdlib.h>
 #include <string.h>
 #include <inttypes.h>