add initial project

Author: schubev

.gitignore

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+/node_modules

README.md

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+# windows-binary-architecture
+
+Find the target CPU architecture of Windows binaries (DLLs, EXEs and others).
+
+The module exposes a single function, `getTargetArch(path, callback(err,
+archName, archCode))` which opens an executable file and determines what CPU
+architecture the file was built for, by calling your callback with a name for
+the architecture and its code, according to the table on [the Windows
+documentation](https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#machine-types),
+reproduced here.
+
+|Name|Value|Description|
+|--|--|--|
+|UNKNOWN| 0x0| The contents of this field are assumed to be applicable to any machine type|
+|AM33| 0x1d3| Matsushita AM33|
+|AMD64| 0x8664| x64|
+|ARM| 0x1c0| ARM little endian|
+|ARM64| 0xaa64| ARM64 little endian|
+|ARMNT| 0x1c4| ARM Thumb-2 little endian|
+|EBC| 0xebc| EFI byte code|
+|I386| 0x14c| Intel 386 or later processors and compatible processors|
+|IA64| 0x200| Intel Itanium processor family|
+|M32R| 0x9041| Mitsubishi M32R little endian|
+|MIPS16| 0x266| MIPS16|
+|MIPSFPU| 0x366| MIPS with FPU|
+|MIPSFPU16| 0x466| MIPS16 with FPU|
+|POWERPC| 0x1f0| Power PC little endian|
+|POWERPCFP| 0x1f1| Power PC with floating point support|
+|R4000| 0x166| MIPS little endian|
+|RISCV32| 0x5032| RISC-V 32-bit address space|
+|RISCV64| 0x5064| RISC-V 64-bit address space|
+|RISCV128| 0x5128| RISC-V 128-bit address space|
+|SH3| 0x1a2| Hitachi SH3|
+|SH3DSP| 0x1a3| Hitachi SH3 DSP|
+|SH4| 0x1a6| Hitachi SH4|
+|SH5| 0x1a8| Hitachi SH5|
+|THUMB| 0x1c2| Thumb|
+|WCEMIPSV2| 0x169| MIPS little-endian WCE v2 |
+|`null`| — | Unknown architecture, name is `null` and the architecture code is sent to the callback as-is|

index.js

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+'use strict'
+
+var fs = require('fs')
+var path = require('path')
+
+module.exports = getTargetArch
+
+// DWORD for offset of PE signature; see
+// https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#ms-dos-stub-image-only
+var SIGNATURE_OFFSET_OFFSET = 0x3c
+
+function getTargetArch(path, callback) {
+  fs.open(path, 'r', function(err, fd) {
+    if (err) return callback(err)
+    readMagic(fd, function(err, archName, archCode) {
+      fs.close(fd)
+      callback(err, archName, archCode)
+    })
+  })
+}
+
+function readMagic(fd, callback) {
+  var buffer = Buffer.alloc(4)
+  fs.read(fd, buffer, 0, 2, 0, function(err, bytesRead) {
+    if (err) return callback(err)
+    if (bytesRead !== 2) return callback(new Error('failed to read MZ magic'))
+    var magic = buffer.readInt16BE()
+    var bigEndian = null
+    if (magic === 0x5a4d)
+      bigEndian = true
+    else if (magic === 0x4d5a)
+      bigEndian = false
+    else
+      return callback(new Error('not a DOS-MZ file'))
+    readTargetArch(fd, bigEndian, callback)
+  })
+}
+
+function readTargetArch(fd, bigEndian, callback) {
+  var buffer = Buffer.alloc(4)
+  fs.read(fd, buffer, 0, 4, SIGNATURE_OFFSET_OFFSET, function(err, bytesRead) {
+    if (err) return callback(err)
+    if (bytesRead !== 4) return callback(new Error('failed to read PE signature offset'))
+    var signatureOffset = bigEndian ? buffer.readUInt32BE() : buffer.readUInt32LE()
+    var targetArchOffset = signatureOffset + 4
+    fs.read(fd, buffer, 0, 2, targetArchOffset, function(err, bytesRead) {
+      if (err) return callback(err)
+      if (bytesRead !== 2) return callback(new Error('failed to read PE architecture field'))
+      var targetArchCode = bigEndian ? buffer.readUInt16BE() : buffer.readUInt16LE()
+      var targetArchName = architectureNameByCode(targetArchCode)
+      callback(null, targetArchName, targetArchCode)
+    })
+  })
+}
+
+// see https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#machine-types
+function architectureNameByCode(code) {
+  switch (code) {
+    case 0x0:
+      return 'UNKNOWN'
+    case 0x1d3:
+      return 'AM33'
+    case 0x8664:
+      return 'AMD64'
+    case 0x1c0:
+      return 'ARM'
+    case 0xaa64:
+      return 'ARM64'
+    case 0x1c4:
+      return 'ARMNT'
+    case 0xebc:
+      return 'EBC'
+    case 0x14c:
+      return 'I386'
+    case 0x200:
+      return 'IA64'
+    case 0x9041:
+      return 'M32R'
+    case 0x266:
+      return 'MIPS16'
+    case 0x366:
+      return 'MIPSFPU'
+    case 0x466:
+      return 'MIPSFPU16'
+    case 0x1f0:
+      return 'POWERPC'
+    case 0x1f1:
+      return 'POWERPCFP'
+    case 0x166:
+      return 'R4000'
+    case 0x5032:
+      return 'RISCV32'
+    case 0x5064:
+      return 'RISCV64'
+    case 0x5128:
+      return 'RISCV128'
+    case 0x1a2:
+      return 'SH3'
+    case 0x1a3:
+      return 'SH3DSP'
+    case 0x1a6:
+      return 'SH4'
+    case 0x1a8:
+      return 'SH5'
+    case 0x1c2:
+      return 'THUMB'
+    case 0x169:
+      return 'WCEMIPSV2'
+    default:
+      return null
+  }
+}

index.test.js

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+var getTargetArch = require('./index.js')
+
+describe(getTargetArch, function() {
+  it.each([
+    ['I386', 0x14c],
+    ['AMD64', 0x8664],
+  ])('detects %s', function(expectedArchName, expectedArchCode, done) {
+    getTargetArch('./test.' + expectedArchName + '.dll', function(err, actualArchName, actualArchCode) {
+      expect(err).toBeNull()
+      expect(actualArchCode).toBe(expectedArchCode)
+      expect(actualArchName).toBe(expectedArchName)
+      done()
+    })
+  })
+
+  it('handles big-endian', function(done) {
+    getTargetArch('./test.big-endian.dll', function(err, architectureName, architectureCode) {
+      expect(err).toBeNull()
+      expect(architectureName).toBe('MIPS16')
+      expect(architectureCode).toBe(0x266)
+      done()
+    })
+  })
+
+  it('errors when file does not exist', function(done) {
+    getTargetArch('./nothere', function(err) {
+      expect(err).not.toBeNull()
+      done()
+    })
+  })
+
+  it('errors when MZ magic cannot be read', function(done) {
+    getTargetArch('./test.no-mz.dll', function(err) {
+      expect(String(err)).toBe('Error: failed to read MZ magic')
+      done()
+    })
+  })
+
+  it('errors when MZ magic is incorrect', function(done) {
+    getTargetArch('./test.bad-mz.dll', function(err) {
+      expect(String(err)).toBe('Error: not a DOS-MZ file')
+      done()
+    })
+  })
+})