Fix one (of many) build issues on Windows

.github/workflows/ci.yml

@@ -13,18 +13,17 @@ jobs:
     name: ${{ matrix.friendlyName }}
     runs-on: ${{ matrix.os }}
     timeout-minutes: 10
-
     strategy:
       fail-fast: false
       matrix:
-        node: [20.12.2]
-        os: [macos-latest, windows-latest, ubuntu-latest]
+        node: [12.14.1]
+        os: [macos-10.14, windows-2019, ubuntu-18.04]
         include:
-          - os: macos-latest
+          - os: macos-10.14
             friendlyName: macOS
-          - os: windows-latest
+          - os: windows-2019
             friendlyName: Windows
-          - os: ubuntu-latest
+          - os: ubuntu-18.04
             friendlyName: Linux
     steps:
       - uses: actions/checkout@v2
@@ -34,26 +33,19 @@ jobs:
         uses: actions/setup-node@v1
         with:
           node-version: ${{ matrix.node }}
-      - name: Install Python setup tools
-        run: |
-          python -m pip install --upgrade setuptools packaging
       - name: Install and build
-        run: |
-          yarn install
-          yarn build
+        run: yarn
       - name: Lint
         run: yarn lint
       - name: Test
         run: yarn test
         shell: bash
-      - name: Prebuild (x64)
-        run: npm run prebuild-napi-x64
-      - name: Prebuild (arm64)
-        run: npm run prebuild-napi-arm64
-        if: ${{ matrix.os != 'ubuntu-latest' }}
-      - name: Prebuild (Windows x86)
-        run: npm run prebuild-napi-ia32
-        if: ${{ matrix.os == 'windows-latest' }}
+      - name: Prebuild Node x64
+        run: yarn prebuild-node
+      - name: Prebuild Electron x64
+        run: yarn prebuild-electron
+      - name: Prebuild Electron arm64
+        run: yarn prebuild-electron-arm64
       - name: Publish
         if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')
         run: yarn upload

.node-version

@@ -1 +1 @@
-20.12.2
+12.14.1

README.md

@@ -2,7 +2,7 @@
 
 A cross-platform no-dependency C executable trampoline which lets GitHub Desktop
 intercede in order to provide Git with any additional info it needs (like
-credentials through `GIT_ASKPASS` or `SSH_ASKPASS`).
+credentials through `GIT_ASKPASS`).
 
 The intention is to support the same platforms that
 [Electron supports](https://www.electronjs.org/docs/tutorial/support#supported-platforms).
@@ -60,7 +60,7 @@ The equivalent Bash shell code looks like this:
 
 ```sh
   # environment variable
-  GIT_ASKPASS="C:/some/path/to/desktop-askpass-trampoline.exe" \
+  GIT_ASKPASS="C:/some/path/to/desktop-trampoline.exe" \
   # ensure Git doesn't block the process waiting for the user to provide input
   GIT_TERMINAL_PROMPT=0 \
   git \
@@ -125,15 +125,3 @@ Thanks to this, with only one generic trampoline that forwards everything via
 that TCP socket, the implementation for every possible protocol like
 `GIT_ASKPASS` can live within the GitHub Desktop codebase instead of having
 multiple trampoline executables.
-
-## SSH Wrapper
-
-Along with the trampoline, an SSH wrapper is provided for macOS. The reason for
-this is macOS before Monterey include an "old" version of OpenSSH that will
-ignore the `SSH_ASKPASS` variable unless it's unable to write to a tty.
-
-This SSH wrapper achieves exactly that: just runs whatever `ssh` exists in the
-path in a way that will use `SSH_ASKPASS` when necessary.
-
-More recent versions of OpenSSH (starting with 8.3) don't require this wrapper,
-since they added support for a new `SSH_ASKPASS_REQUIRE` environment variable.

binding.gyp

@@ -1,10 +1,13 @@
   {
-    'target_defaults': {
-        'defines': [
-          "NAPI_VERSION=<(napi_build_version)",
+    'targets': [
+      {
+        'target_name': 'desktop-trampoline',
+        'type': 'executable',
+        'sources': [
+          'src/desktop-trampoline.c',
+          'src/socket.c'
         ],
         'include_dirs': [
-          '<!(node -p "require(\'node-addon-api\').include_dir")',
           'include'
         ],
         'xcode_settings': {
@@ -24,61 +27,20 @@
           '-pie',
           '-D_FORTIFY_SOURCE=1',
           '-fstack-protector-strong',
-          '-Werror=format-security',
-          '-fno-exceptions'
+          '-Werror=format-security'
         ],
-        'cflags_cc!': [ '-fno-exceptions' ],
         'ldflags!': [
           '-z relro',
           '-z now'
         ],
-        'msvs_settings': {
-          'VCCLCompilerTool': { 'ExceptionHandling': 1 },
-        },
-        'conditions': [
-          ['OS=="win"', { 'defines': [ 'WINDOWS' ] }]
-        ]
-    },
-    'targets': [
-      {
-        'target_name': 'desktop-askpass-trampoline',
-        'type': 'executable',
-        'sources': [
-          'src/desktop-trampoline.c',
-          'src/socket.c'
-        ],
         'conditions': [
           ['OS=="win"', {
+            'defines': [ 'WINDOWS' ],
             'link_settings': {
               'libraries': [ 'Ws2_32.lib' ]
             }
           }]
         ]
       },
-      {
-        'target_name': 'desktop-credential-helper-trampoline',
-        'type': 'executable',
-        'defines': [
-          'CREDENTIAL_HELPER'
-        ],
-        'sources': [
-          'src/desktop-trampoline.c',
-          'src/socket.c'
-        ],
-        'conditions': [
-          ['OS=="win"', {
-            'link_settings': {
-              'libraries': [ 'Ws2_32.lib' ]
-            }
-          }]
-        ]
-      },
-      {
-        'target_name': 'ssh-wrapper',
-        'type': 'executable',
-        'sources': [
-          'src/ssh-wrapper.c'
-        ],
-      },
     ],
   }

index.d.ts

@@ -1,8 +1,2 @@
-export function getDesktopAskpassTrampolinePath(): string
-export function getDesktopAskpassTrampolineFilename(): string
-
-export function getDesktopCredentialHelperTrampolinePath(): string
-export function getDesktopCredentialHelperTrampolineFilename(): string
-
-export function getSSHWrapperPath(): string
-export function getSSHWrapperFilename(): string
+export function getDesktopTrampolinePath(): string
+export function getDesktopTrampolineFilename(): string

index.js

@@ -1,48 +1,21 @@
 const Path = require('path')
 
-function getDesktopAskpassTrampolinePath() {
+function getDesktopTrampolinePath() {
   return Path.join(
     __dirname,
     'build',
     'Release',
-    getDesktopAskpassTrampolineFilename()
+    getDesktopTrampolineFilename()
   )
 }
 
-function getDesktopAskpassTrampolineFilename() {
+function getDesktopTrampolineFilename() {
   return process.platform === 'win32'
-    ? 'desktop-askpass-trampoline.exe'
-    : 'desktop-askpass-trampoline'
-}
-
-function getDesktopCredentialHelperTrampolinePath() {
-  return Path.join(
-    __dirname,
-    'build',
-    'Release',
-    getDesktopCredentialHelperTrampolineFilename()
-  )
-}
-
-function getDesktopCredentialHelperTrampolineFilename() {
-  return process.platform === 'win32'
-    ? 'desktop-credential-helper-trampoline.exe'
-    : 'desktop-credential-helper-trampoline'
-}
-
-function getSSHWrapperPath() {
-  return Path.join(__dirname, 'build', 'Release', getSSHWrapperFilename())
-}
-
-function getSSHWrapperFilename() {
-  return process.platform === 'win32' ? 'ssh-wrapper.exe' : 'ssh-wrapper'
+    ? 'desktop-trampoline.exe'
+    : 'desktop-trampoline'
 }
 
 module.exports = {
-  getDesktopAskpassTrampolinePath,
-  getDesktopAskpassTrampolineFilename,
-  getDesktopCredentialHelperTrampolinePath,
-  getDesktopCredentialHelperTrampolineFilename,
-  getSSHWrapperPath,
-  getSSHWrapperFilename,
+  getDesktopTrampolinePath,
+  getDesktopTrampolineFilename,
 }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "desktop-trampoline",
-  "version": "0.9.9",
+  "version": "0.9.4",
   "main": "index.js",
   "keywords": [],
   "author": "",
@@ -15,10 +15,10 @@
     "test": "jest",
     "lint": "prettier -c **/*.js **/*.md",
     "lint:fix": "prettier --write **/*.js **/*.md",
-    "prebuild-napi-x64": "prebuild -t 3 -r napi -a x64 --strip --include-regex \"(desktop-trampoline|ssh-wrapper)(\\.exe)?$\"",
-    "prebuild-napi-ia32": "prebuild -t 3 -r napi -a ia32 --strip --include-regex \"(desktop-trampoline|ssh-wrapper)(\\.exe)?$\"",
-    "prebuild-napi-arm64": "prebuild -t 3 -r napi -a arm64 --strip --include-regex \"(desktop-trampoline|ssh-wrapper)(\\.exe)?$\"",
-    "prebuild-all": "yarn prebuild-napi-x64 && yarn prebuild-napi-ia32 && yarn prebuild-napi-arm64",
+    "prebuild-node": "prebuild -t 10.11.0 -t 11.9.0 -t 12.0.0 -t 14.8.0 --strip --include-regex \"desktop-trampoline(\\.exe)?$\"",
+    "prebuild-electron": "prebuild -t 7.0.0 -t 8.0.0 -t 9.0.0 -t 10.0.0 -t 11.0.0 -r electron --strip --include-regex \"desktop-trampoline(\\.exe)?$\"",
+    "prebuild-electron-arm64": "prebuild -t 7.0.0 -t 8.0.0 -t 9.0.0 -t 10.0.0 -t 11.0.0 -r electron -a arm64 --strip --include-regex \"desktop-trampoline(\\.exe)?$\"",
+    "prebuild-all": "yarn prebuild-node && yarn prebuild-electron && yarn prebuild-electron-arm64",
     "upload": "node ./script/upload.js"
   },
   "repository": {
@@ -29,24 +29,11 @@
     "url": "https://github.com/desktop/desktop-trampoline/issues"
   },
   "homepage": "https://github.com/desktop/desktop-trampoline#readme",
-  "dependencies": {
-    "node-addon-api": "^4.3.0",
-    "prebuild-install": "^7.1.2"
-  },
   "devDependencies": {
-    "jest": "^27.5.0",
-    "node-gyp": "^10.1.0",
-    "prebuild": "^13.0.1",
-    "prettier": "^2.5.1",
-    "split2": "^4.1.0"
-  },
-  "binary": {
-    "napi_versions": [
-      3
-    ]
-  },
-  "config": {
-    "runtime": "napi",
-    "target": 3
+    "jest": "^26.4.2",
+    "node-gyp": "^7.1.0",
+    "prebuild": "^10.0.1",
+    "prettier": "^2.1.2",
+    "split2": "^3.2.2"
   }
 }

src/desktop-trampoline.c

@@ -1,5 +1,7 @@
 #include <errno.h>
+#include <fcntl.h>
 #include <stdarg.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -9,13 +11,6 @@
 #define BUFFER_LENGTH 4096
 #define MAXIMUM_NUMBER_LENGTH 33
 
-#ifdef CREDENTIAL_HELPER
-  #define DESKTOP_TRAMPOLINE_IDENTIFIER "CREDENTIALHELPER"
-#else
-  #define DESKTOP_TRAMPOLINE_IDENTIFIER "ASKPASS"
-#endif
-
-
 #define WRITE_STRING_OR_EXIT(dataName, dataString) \
 if (writeSocket(socket, dataString, strlen(dataString) + 1) != 0) { \
   printSocketError("ERROR: Couldn't send " dataName); \
@@ -24,9 +19,12 @@ if (writeSocket(socket, dataString, strlen(dataString) + 1) != 0) { \
 
 // This is a list of valid environment variables that GitHub Desktop might
 // send or expect to receive.
-#define NUMBER_OF_VALID_ENV_VARS 1
+#define NUMBER_OF_VALID_ENV_VARS 4
 static const char *sValidEnvVars[NUMBER_OF_VALID_ENV_VARS] = {
+  "DESKTOP_TRAMPOLINE_IDENTIFIER",
   "DESKTOP_TRAMPOLINE_TOKEN",
+  "DESKTOP_USERNAME",
+  "DESKTOP_ENDPOINT",
 };
 
 /** Returns 1 if a given env variable is valid, 0 otherwise. */
@@ -48,6 +46,42 @@ int isValidEnvVar(char *env) {
   return 0;
 }
 
+/**
+ * Reads a string from the socket, reading first 2 bytes to get its length and
+ * then the string itself.
+ */
+ssize_t readDelimitedString(SOCKET socket, char *buffer, size_t bufferSize) {
+  uint16_t outputLength = 0;
+  if (readSocket(socket, &outputLength, sizeof(uint16_t)) < (int)sizeof(uint16_t)) {
+      printSocketError("ERROR: Error reading from socket");
+      return -1;
+  }
+
+  if (outputLength > bufferSize) {
+    fprintf(stderr, "ERROR: received string is bigger than buffer (%d > %zu)", outputLength, bufferSize);
+    return -1;
+  }
+
+  size_t totalBytesRead = 0;
+  ssize_t bytesRead = 0;
+
+  // Read output from server
+  do {
+    bytesRead = readSocket(socket, buffer + totalBytesRead, outputLength - totalBytesRead);
+
+    if (bytesRead == -1) {
+      printSocketError("ERROR: Error reading from socket");
+      return -1;
+    }
+
+    totalBytesRead += bytesRead;
+  } while (bytesRead > 0);
+
+  buffer[totalBytesRead] = '\0';
+
+  return totalBytesRead;
+}
+
 int runTrampolineClient(SOCKET *outSocket, int argc, char **argv, char **envp) {
   char *desktopPortString;
 
@@ -87,9 +121,8 @@ int runTrampolineClient(SOCKET *outSocket, int argc, char **argv, char **envp) {
   }
 
   // Get the number of environment variables
-  char *validEnvVars[NUMBER_OF_VALID_ENV_VARS + 1];
-  validEnvVars[0] = "DESKTOP_TRAMPOLINE_IDENTIFIER=" DESKTOP_TRAMPOLINE_IDENTIFIER;
-  int envc = 1;
+  char *validEnvVars[NUMBER_OF_VALID_ENV_VARS];
+  int envc = 0;
   for (char **env = envp; *env != 0; env++) {
     if (isValidEnvVar(*env)) {
       validEnvVars[envc] = *env;
@@ -107,37 +140,57 @@ int runTrampolineClient(SOCKET *outSocket, int argc, char **argv, char **envp) {
     WRITE_STRING_OR_EXIT("environment variable", validEnvVars[idx]);
   }
 
-  char stdinBuffer[BUFFER_LENGTH + 1];
-  int stdinBytes = 0;
-
-  #ifdef CREDENTIAL_HELPER
-    stdinBytes = fread(stdinBuffer, sizeof(char), BUFFER_LENGTH, stdin);
-  #endif
-
-  stdinBuffer[stdinBytes] = '\0';
-  WRITE_STRING_OR_EXIT("stdin", stdinBuffer);
-
   char buffer[BUFFER_LENGTH + 1];
-  size_t totalBytesRead = 0;
-  ssize_t bytesRead = 0;
+  size_t totalBytesWritten = 0;
+  ssize_t bytesToWrite = 0;
 
-  // Read output from server
+  // Make stdin reading non-blocking, to prevent getting stuck when no data is
+  // provided via stdin.
+  int flags = fcntl(STDIN_FILENO, F_GETFL, 0);
+  fcntl(STDIN_FILENO, F_SETFL, flags | O_NONBLOCK);
+
+  // Send stdin data
   do {
-    bytesRead = readSocket(socket, buffer + totalBytesRead, BUFFER_LENGTH - totalBytesRead);
+    bytesToWrite = read(0, buffer, BUFFER_LENGTH);
 
-    if (bytesRead == -1) {
-      printSocketError("ERROR: Error reading from socket");
+    if (bytesToWrite == -1) {
+      if (totalBytesWritten == 0) {
+        // No stdin content found, continuing...
+        break;
+      } else {
+        fprintf(stderr, "ERROR: Error reading stdin data");
+        return 1;
+      }
+    }
+
+    if (writeSocket(socket, buffer, bytesToWrite) != 0) {
+      printSocketError("ERROR: Couldn't send stdin data");
       return 1;
     }
 
-    totalBytesRead += bytesRead;
-  } while (bytesRead > 0);
+    totalBytesWritten += bytesToWrite;
+  } while (bytesToWrite > 0);
 
-  buffer[totalBytesRead] = '\0';
+  writeSocket(socket, "\0", 1);
+
+  // Read stdout from the server
+  if (readDelimitedString(socket, buffer, BUFFER_LENGTH) == -1) {
+    fprintf(stderr, "ERROR: Couldn't read stdout from socket");
+    return 1;
+  }
 
   // Write that output to stdout
   fprintf(stdout, "%s", buffer);
 
+  // Read stderr from the server
+  if (readDelimitedString(socket, buffer, BUFFER_LENGTH) == -1) {
+    fprintf(stderr, "ERROR: Couldn't read stdout from socket");
+    return 1;
+  }
+
+  // Write that output to stderr
+  fprintf(stderr, "%s", buffer);
+
   return 0;
 }
 

src/ssh-wrapper.c

@@ -1,37 +0,0 @@
-#ifdef WINDOWS
-
-int main(int argc, char **argv) {
-  // Not needed on Windows, this will just create a dummy executable
-  return -1;
-}
-
-#else
-
-#include <unistd.h>
-#include <stdio.h>
-
-/**
- * This is a wrapper for the ssh command. It is used to make sure ssh runs without
- * a tty on macOS, allowing GitHub Desktop to intercept different prompts from
- * ssh (e.g. passphrase, adding a host to the list of known hosts...).
- * This is not necessary on more recent versions of OpenSSH (starting with v8.3)
- * which include support for the SSH_ASKPASS_REQUIRE environment variable.
- */
-int main(int argc, char **argv) {
-  pid_t child = fork();
-
-  if (child < 0) {
-    fprintf(stderr, "Failed to fork\n");
-    return -1;
-  }
-
-  if (child != 0) {
-    // This is the parent process. Just exit.
-    return 0;
-  }
-
-  setsid();
-  return execvp("ssh", argv);
-}
-
-#endif

test/desktop-trampoline.test.js

@@ -1,153 +0,0 @@
-const { stat, access } = require('fs').promises
-const { constants } = require('fs')
-const { execFile } = require('child_process')
-const { promisify } = require('util')
-const {
-  getDesktopAskpassTrampolinePath,
-  getDesktopCredentialHelperTrampolinePath,
-} = require('../index')
-const split2 = require('split2')
-const { createServer } = require('net')
-
-const askPassTrampolinePath = getDesktopAskpassTrampolinePath()
-const helperTrampolinePath = getDesktopCredentialHelperTrampolinePath()
-const run = promisify(execFile)
-
-describe('desktop-trampoline', () => {
-  it('exists and is a regular file', async () =>
-    expect((await stat(askPassTrampolinePath)).isFile()).toBe(true))
-
-  it('can be executed by current process', () =>
-    access(askPassTrampolinePath, constants.X_OK))
-
-  it('fails when required environment variables are missing', () =>
-    expect(run(askPassTrampolinePath, ['Username'])).rejects.toThrow())
-
-  const captureSession = () => {
-    const output = []
-    let resolveOutput = null
-
-    const outputPromise = new Promise(resolve => {
-      resolveOutput = resolve
-    })
-
-    const server = createServer(socket => {
-      let timeoutId = null
-      socket.pipe(split2(/\0/)).on('data', data => {
-        output.push(data.toString('utf8'))
-
-        // Hack: consider the session finished after 100ms of inactivity.
-        // In a real-world scenario, you'd have to parse the data to know when
-        // the session is finished.
-        if (timeoutId !== null) {
-          clearTimeout(timeoutId)
-          timeoutId = null
-        }
-        timeoutId = setTimeout(() => {
-          resolveOutput(output)
-          socket.end()
-          server.close()
-        }, 100)
-      })
-    })
-
-    const serverPortPromise = new Promise((resolve, reject) => {
-      server.on('error', e => reject(e))
-      server.listen(0, '127.0.0.1', () => {
-        resolve(server.address().port)
-      })
-    })
-
-    return [serverPortPromise, outputPromise]
-  }
-
-  it('forwards arguments and valid environment variables correctly', async () => {
-    const [portPromise, outputPromise] = captureSession()
-    const port = await portPromise
-
-    const env = {
-      DESKTOP_TRAMPOLINE_TOKEN: '123456',
-      DESKTOP_PORT: port,
-      INVALID_VARIABLE: 'foo bar',
-    }
-    const opts = { env }
-
-    await run(askPassTrampolinePath, ['baz'], opts)
-
-    const output = await outputPromise
-    const outputArguments = output.slice(1, 2)
-    expect(outputArguments).toStrictEqual(['baz'])
-    // output[2] is the number of env variables
-    const envc = parseInt(output[2])
-    const outputEnv = output.slice(3, 3 + envc)
-    expect(outputEnv).toHaveLength(2)
-    expect(outputEnv).toContain('DESKTOP_TRAMPOLINE_TOKEN=123456')
-    expect(outputEnv).toContain('DESKTOP_TRAMPOLINE_IDENTIFIER=ASKPASS')
-  })
-
-  it('forwards stdin when running in credential-helper mode', async () => {
-    const [portPromise, outputPromise] = captureSession()
-    const port = await portPromise
-
-    const cp = run(helperTrampolinePath, ['get'], {
-      env: { DESKTOP_PORT: port },
-    })
-    cp.child.stdin.end('oh hai\n')
-
-    await cp
-
-    const output = await outputPromise
-    expect(output.at(-1)).toBe('oh hai\n')
-  })
-
-  it("doesn't forward stdin when running in askpass mode", async () => {
-    const [portPromise, outputPromise] = captureSession()
-    const port = await portPromise
-
-    const cp = run(askPassTrampolinePath, ['get'], {
-      env: { DESKTOP_PORT: port },
-    })
-    cp.child.stdin.end('oh hai\n')
-
-    await cp
-
-    const output = await outputPromise
-    expect(output.at(-1)).toBe('')
-  })
-
-  it('askpass handler ignores the DESKTOP_TRAMPOLINE_IDENTIFIER env var', async () => {
-    const [portPromise, outputPromise] = captureSession()
-    const port = await portPromise
-
-    const cp = run(askPassTrampolinePath, ['get'], {
-      env: { DESKTOP_PORT: port, DESKTOP_TRAMPOLINE_IDENTIFIER: 'foo' },
-    })
-    cp.child.stdin.end('oh hai\n')
-
-    await cp
-
-    const output = await outputPromise
-    const envc = parseInt(output[2])
-    const outputEnv = output.slice(3, 3 + envc)
-    expect(outputEnv).toContain('DESKTOP_TRAMPOLINE_IDENTIFIER=ASKPASS')
-  })
-
-  it('credential handler ignores the DESKTOP_TRAMPOLINE_IDENTIFIER env var', async () => {
-    const [portPromise, outputPromise] = captureSession()
-    const port = await portPromise
-
-    const cp = run(helperTrampolinePath, ['get'], {
-      env: { DESKTOP_PORT: port, DESKTOP_TRAMPOLINE_IDENTIFIER: 'foo' },
-    })
-    cp.child.stdin.end('oh hai\n')
-
-    await cp
-
-    const output = await outputPromise
-    const envc = parseInt(output[2])
-    const outputEnv = output.slice(3, 3 + envc)
-    expect(outputEnv).toContain(
-      'DESKTOP_TRAMPOLINE_IDENTIFIER=CREDENTIALHELPER'
-    )
-  })
-})

test/index.test.js

@@ -0,0 +1,183 @@
+const { stat, access } = require('fs').promises
+const { constants } = require('fs')
+const { execFile } = require('child_process')
+const { promisify } = require('util')
+const { getDesktopTrampolinePath } = require('../index')
+const split2 = require('split2')
+const { createServer } = require('net')
+
+const trampolinePath = getDesktopTrampolinePath()
+const run = promisify(execFile)
+
+async function startTrampolineServer(output, stdout = '', stderr = '') {
+  const server = createServer(socket => {
+    socket.pipe(split2(/\0/)).on('data', data => {
+      output.push(data.toString('utf8'))
+    })
+
+    const buffer = Buffer.alloc(2, 0)
+
+    // Send stdout
+    buffer.writeUInt16LE(stdout.length, 0)
+    socket.write(buffer)
+    socket.write(stdout)
+
+    // Send stderr
+    buffer.writeUInt16LE(stderr.length, 0)
+    socket.write(buffer)
+    socket.write(stderr)
+
+    // Close the socket
+    socket.end()
+  })
+  server.unref()
+
+  const startServer = async () => {
+    return new Promise((resolve, reject) => {
+      server.on('error', e => reject(e))
+      server.listen(0, '127.0.0.1', () => {
+        resolve(server.address().port)
+      })
+    })
+  }
+
+  return {
+    server,
+    port: await startServer(),
+  }
+}
+
+describe('desktop-trampoline', () => {
+  it('exists and is a regular file', async () =>
+    expect((await stat(trampolinePath)).isFile()).toBe(true))
+
+  it('can be executed by current process', () =>
+    access(trampolinePath, constants.X_OK))
+
+  it('fails when required environment variables are missing', () =>
+    expect(run(trampolinePath, ['Username'])).rejects.toThrow())
+
+  describe('with a trampoline server', () => {
+    let server = null
+    let output = []
+    let baseEnv = {}
+
+    async function configureTrampolineServer(stdout = '', stderr = '') {
+      output = []
+      const serverInfo = await startTrampolineServer(output, stdout, stderr)
+      server = serverInfo.server
+      baseEnv = {
+        DESKTOP_PORT: serverInfo.port,
+      }
+    }
+
+    afterEach(() => {
+      server.close()
+    })
+
+    it('forwards arguments and valid environment variables correctly without stdin', async () => {
+      await configureTrampolineServer()
+
+      const env = {
+        ...baseEnv,
+        DESKTOP_TRAMPOLINE_IDENTIFIER: '123456',
+        DESKTOP_USERNAME: 'sergiou87',
+        DESKTOP_USERNAME_FAKE: 'fake-user',
+        INVALID_VARIABLE: 'foo bar',
+      }
+      const opts = { env }
+
+      await run(trampolinePath, ['baz'], opts)
+
+      const outputArguments = output.slice(1, 2)
+      expect(outputArguments).toStrictEqual(['baz'])
+      // output[2] is the number of env variables
+      const outputEnv = output.slice(3, output.length - 1)
+      expect(outputEnv).toHaveLength(2)
+      expect(outputEnv).toContain('DESKTOP_TRAMPOLINE_IDENTIFIER=123456')
+      expect(outputEnv).toContain(`DESKTOP_USERNAME=sergiou87`)
+
+      expect(output[output.length - 1]).toStrictEqual('')
+    })
+
+    it('forwards arguments, environment variables and stdin correctly', async () => {
+      await configureTrampolineServer()
+
+      const env = {
+        ...baseEnv,
+        DESKTOP_TRAMPOLINE_IDENTIFIER: '123456',
+        DESKTOP_USERNAME: 'sergiou87',
+      }
+      const opts = {
+        env,
+        stdin: 'This is a test\nWith a multiline\nStandard input text',
+      }
+
+      const run = new Promise((resolve, reject) => {
+        const process = execFile(trampolinePath, ['baz'], opts, function (
+          err,
+          stdout,
+          stderr
+        ) {
+          if (!err) {
+            resolve({ stdout, stderr, exitCode: 0 })
+            return
+          }
+
+          reject(err)
+        })
+
+        process.stdin.end(
+          'This is a test\nWith a multiline\nStandard input text',
+          'utf-8'
+        )
+      })
+      await run
+
+      const outputArguments = output.slice(1, 2)
+      expect(outputArguments).toStrictEqual(['baz'])
+      // output[2] is the number of env variables
+      const outputEnv = output.slice(3, output.length - 1)
+      expect(outputEnv).toHaveLength(2)
+      expect(outputEnv).toContain('DESKTOP_TRAMPOLINE_IDENTIFIER=123456')
+      expect(outputEnv).toContain(`DESKTOP_USERNAME=sergiou87`)
+
+      expect(output[output.length - 1]).toBe(
+        'This is a test\nWith a multiline\nStandard input text'
+      )
+    })
+
+    it('outputs the same stdout received from the server, when no stderr is specified', async () => {
+      await configureTrampolineServer('This is the command stdout', '')
+
+      const opts = { env: baseEnv }
+      const result = await run(trampolinePath, ['baz'], opts)
+
+      expect(result.stdout).toStrictEqual('This is the command stdout')
+      expect(result.stderr).toStrictEqual('')
+    })
+
+    it('outputs the same stderr received from the server, when no stdout is specified', async () => {
+      await configureTrampolineServer('', 'This is the command stderr')
+
+      const opts = { env: baseEnv }
+      const result = await run(trampolinePath, ['baz'], opts)
+
+      expect(result.stdout).toStrictEqual('')
+      expect(result.stderr).toStrictEqual('This is the command stderr')
+    })
+
+    it('outputs the same stdout and stderr received from the server, when both are specified', async () => {
+      await configureTrampolineServer(
+        'This is the command stdout',
+        'This is the command stderr'
+      )
+
+      const opts = { env: baseEnv }
+      const result = await run(trampolinePath, ['baz'], opts)
+
+      expect(result.stdout).toStrictEqual('This is the command stdout')
+      expect(result.stderr).toStrictEqual('This is the command stderr')
+    })
+  })
+})

test/ssh-wrapper.test.js

@@ -1,42 +0,0 @@
-const { stat, access } = require('fs').promises
-const { constants } = require('fs')
-const { execFile } = require('child_process')
-const { promisify } = require('util')
-const { getSSHWrapperPath } = require('../index')
-
-const sshWrapperPath = getSSHWrapperPath()
-const run = promisify(execFile)
-
-describe('ssh-wrapper', () => {
-  it('exists and is a regular file', async () =>
-    expect((await stat(sshWrapperPath)).isFile()).toBe(true))
-
-  // On Windows, the binary generated is just useless, so no point to test it.
-  // Also, this won't be used on Linux (for now at least), so don't bother to
-  // run the tests there.
-  if (process.platform !== 'darwin') {
-    return
-  }
-
-  it('can be executed by current process', () =>
-    access(sshWrapperPath, constants.X_OK))
-
-  it('attempts to use ssh-askpass program', async () => {
-    // Try to connect to github.com with a non-existent known_hosts file to force
-    // ssh to prompt the user and use askpass.
-    const result = await run(
-      sshWrapperPath,
-      ['-o', 'UserKnownHostsFile=/path/to/fake/known_hosts', 'git@github.com'],
-      {
-        env: {
-          SSH_ASKPASS: '/path/to/fake/ssh-askpass',
-          DISPLAY: '.',
-        },
-      }
-    )
-
-    expect(result.stderr).toMatch(
-      /ssh_askpass: exec\(\/path\/to\/fake\/ssh-askpass\): No such file or directory/
-    )
-  })
-})