| 1 | # Copyright (c) Microsoft Corporation. |
| 2 | # Licensed under the MIT License. |
| 3 | |
| 4 | # Creates a CPIO newc format initramfs archive containing a single file named "init" |
| 5 | # with mode 0100755 (rwxr-xr-x), uid 0, gid 0. |
| 6 | |
| 7 | [CmdletBinding()] |
| 8 | param ( |
| 9 | [Parameter(Mandatory)][string]$InputFile, |
| 10 | [Parameter(Mandatory)][string]$OutputFile |
| 11 | ) |
| 12 | |
| 13 | $ErrorActionPreference = "Stop" |
| 14 | Set-StrictMode -Version Latest |
| 15 | |
| 16 | function Write-Pad([System.IO.Stream]$Stream) |
| 17 | { |
| 18 | $remainder = $Stream.Position % 4 |
| 19 | if ($remainder -ne 0) |
| 20 | { |
| 21 | $pad = [byte[]]::new(4 - $remainder) |
| 22 | $Stream.Write($pad, 0, $pad.Length) |
| 23 | } |
| 24 | } |
| 25 | |
| 26 | function Write-CpioEntry([System.IO.Stream]$Stream, [byte[]]$NameBytes, [byte[]]$FileData, [int]$Mode, [uint32]$Mtime) |
| 27 | { |
| 28 | $header = "070701" + # header magic |
| 29 | "00000001" + # inode |
| 30 | ("{0:X8}" -f $Mode) + # mode |
| 31 | "00000000" + # uid |
| 32 | "00000000" + # gid |
| 33 | "00000001" + # nlink |
| 34 | ("{0:X8}" -f $Mtime) + # mtime |
| 35 | ("{0:X8}" -f $FileData.Length) + # filesize |
| 36 | "00000000" + # devmajor |
| 37 | "00000000" + # devminor |
| 38 | "00000000" + # rdevmajor |
| 39 | "00000000" + # rdevminor |
| 40 | ("{0:X8}" -f $NameBytes.Length) + # namesize |
| 41 | "00000000" # check |
| 42 | $headerBytes = [System.Text.Encoding]::ASCII.GetBytes($header) |
| 43 | $Stream.Write($headerBytes, 0, $headerBytes.Length) |
| 44 | $Stream.Write($NameBytes, 0, $NameBytes.Length) |
| 45 | Write-Pad $Stream |
| 46 | if ($FileData.Length -gt 0) |
| 47 | { |
| 48 | $Stream.Write($FileData, 0, $FileData.Length) |
| 49 | Write-Pad $Stream |
| 50 | } |
| 51 | } |
| 52 | |
| 53 | $data = [System.IO.File]::ReadAllBytes($InputFile) |
| 54 | $name = [System.Text.Encoding]::ASCII.GetBytes("init`0") |
| 55 | $mtime = [uint32][System.DateTimeOffset]::UtcNow.ToUnixTimeSeconds() |
| 56 | |
| 57 | $out = [System.IO.File]::Create($OutputFile) |
| 58 | try |
| 59 | { |
| 60 | Write-CpioEntry $out $name $data 0x81ED $mtime # S_IFREG | 0755 |
| 61 | $trailer = [System.Text.Encoding]::ASCII.GetBytes("TRAILER!!!`0") |
| 62 | Write-CpioEntry $out $trailer ([byte[]]::new(0)) 0 0 |
| 63 | } |
| 64 | finally |
| 65 | { |
| 66 | $out.Close() |
| 67 | } |