print: default output based on parent process name (#338)

### Why

We can do better about choosing the output than just checking the OS.
There's a chance someone could be using bash on windows or powershell on
mac

### How

Use Windows API and for linux / mac use some shell code to climb up the
process tree and get the proper name

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: DotNet Format Bot <[email protected]>

src/D2L.Bmx/D2L.Bmx.csproj

@@ -8,6 +8,7 @@
     <InvariantGlobalization>true</InvariantGlobalization>
     <RootNamespace>D2L.Bmx</RootNamespace>
     <LangVersion>preview</LangVersion>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
 
   <ItemGroup>

src/D2L.Bmx/PrintHandler.cs

@@ -25,10 +25,30 @@ public async Task HandleAsync(
 		} else if( string.Equals( output, "json", StringComparison.OrdinalIgnoreCase ) ) {
 			PrintJson( awsCreds );
 		} else {
+			string? procName = null;
 			if( OperatingSystem.IsWindows() ) {
-				PrintPowershell( awsCreds );
-			} else if( OperatingSystem.IsMacOS() || OperatingSystem.IsLinux() ) {
-				PrintBash( awsCreds );
+				procName = WindowsParentProcess.GetParentProcessName().ToLower();
+			} else if( OperatingSystem.IsLinux() || OperatingSystem.IsMacOS() ) {
+				procName = UnixParentProcess.GetParentProcessName().ToLower();
+			}
+
+			switch( procName ) {
+				case "pwsh":
+				case "powershell":
+					PrintPowershell( awsCreds );
+					break;
+				case "zsh":
+				case "bash":
+				case "sh":
+					PrintBash( awsCreds );
+					break;
+				default:
+					if( OperatingSystem.IsWindows() ) {
+						PrintPowershell( awsCreds );
+					} else if( OperatingSystem.IsMacOS() || OperatingSystem.IsLinux() ) {
+						PrintBash( awsCreds );
+					}
+					break;
 			}
 		}
 	}

src/D2L.Bmx/UnixParentProcess.cs

@@ -0,0 +1,36 @@
+using System.Diagnostics;
+
+namespace D2L.Bmx;
+
+/**
+This file may eventually be replaced if the following dotnet runtime api proposals are implemented:
+- https://github.com/dotnet/runtime/issues/21941
+- https://github.com/dotnet/runtime/issues/24423
+*/
+internal class UnixParentProcess {
+
+	public static string GetParentProcessName() {
+		int parentPid = GetParentProcessId( Environment.ProcessId );
+		return Process.GetProcessById( parentPid ).ProcessName;
+	}
+
+	private static int GetParentProcessId( int pid ) {
+		var proccessStartInfo = new ProcessStartInfo {
+			FileName = "ps",
+			ArgumentList = { "-p", $"{pid}", "-o", "ppid=" },
+			RedirectStandardOutput = true,
+		};
+
+		using var proc = Process.Start( proccessStartInfo );
+		if( proc is null ) {
+			return -1;
+		}
+
+		string output = proc.StandardOutput.ReadToEnd();
+		proc.WaitForExit();
+		if( int.TryParse( output.Trim(), out int parentPid ) ) {
+			return parentPid;
+		}
+		return -1;
+	}
+}

src/D2L.Bmx/WindowsParentProcess.cs

@@ -0,0 +1,53 @@
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+
+namespace D2L.Bmx;
+/**
+This file may eventually be replaced if the following dotnet runtime api proposals are implemented:
+- https://github.com/dotnet/runtime/issues/21941
+- https://github.com/dotnet/runtime/issues/24423
+
+Uses the same approach of calling NtQueryInformationProcess as in the PowerShell library
+https://github.com/PowerShell/PowerShell/blob/26f621952910e33840efb0c539fbef1e2a467a0d/src/System.Management.Automation/engine/ProcessCodeMethods.cs
+*/
+internal partial class WindowsParentProcess {
+
+	[LibraryImport( "ntdll.dll", EntryPoint = "NtQueryInformationProcess" )]
+	internal static partial int NtQueryInformationProcess(
+		IntPtr processHandle,
+		int processInformationClass,
+		ref PROCESS_BASIC_INFORMATION processInformation,
+		int processInformationLength,
+		out int returnLength
+	);
+
+	internal struct PROCESS_BASIC_INFORMATION {
+		public IntPtr ExitStatus;
+		public IntPtr PebBaseAddress;
+		public IntPtr AffinityMask;
+		public IntPtr BasePriority;
+		public UIntPtr UniqueProcessId;
+		public UIntPtr InheritedFromUniqueProcessId;
+	}
+
+	private static int GetParentProcessId() {
+		var proc = Process.GetCurrentProcess();
+		var pbi = new PROCESS_BASIC_INFORMATION();
+		int status = NtQueryInformationProcess(
+			proc.Handle,
+			0,
+			ref pbi,
+			Marshal.SizeOf<PROCESS_BASIC_INFORMATION>(),
+			out int infoLen
+		);
+
+		if( status != 0 ) {
+			return -1;
+		}
+		return (int)pbi.InheritedFromUniqueProcessId;
+	}
+
+	public static string GetParentProcessName() {
+		return Process.GetProcessById( GetParentProcessId() ).ProcessName;
+	}
+}