do not inherit fds

(cherry picked from commit f4eb86b)
(cherry picked from commit 7022366)

Author: weissi

Foundation/Process.swift

@@ -8,6 +8,7 @@
 //
 
 import CoreFoundation
+import Darwin
 
 extension Process {
     public enum TerminationReason : Int {
@@ -872,6 +873,16 @@ open class Process: NSObject {
             posix(_CFPosixSpawnFileActionsAddClose(fileActions, fd))
         }
 
+        #if os(macOS)
+        var spawnAttrs: posix_spawnattr_t? = nil
+        posix_spawnattr_init(&spawnAttrs)
+        posix_spawnattr_setflags(&spawnAttrs, .init(POSIX_SPAWN_CLOEXEC_DEFAULT))
+        #else
+        for fd in 3..<getdtablesize() {
+            posix(_CFPosixSpawnFileActionsAddClose(fileActions, fd))
+        }
+        #endif
+
         let fileManager = FileManager()
         let previousDirectoryPath = fileManager.currentDirectoryPath
         if let dir = currentDirectoryURL?.path, !fileManager.changeCurrentDirectoryPath(dir) {
@@ -885,9 +896,16 @@ open class Process: NSObject {
 
         // Launch
         var pid = pid_t()
+        #if os(macOS)
+        guard _CFPosixSpawn(&pid, launchPath, fileActions, &spawnAttrs, argv, envp) == 0 else {
+            throw _NSErrorWithErrno(errno, reading: true, path: launchPath)
+        }
+        #else
         guard _CFPosixSpawn(&pid, launchPath, fileActions, nil, argv, envp) == 0 else {
             throw _NSErrorWithErrno(errno, reading: true, path: launchPath)
         }
+        #endif
+
 
         // Close the write end of the input and output pipes.
         if let pipe = standardInput as? Pipe {

TestFoundation/TestProcess.swift

@@ -750,6 +750,26 @@ class TestProcess : XCTestCase {
         }
     }
 
+    func test_fileDescriptorsAreNotInherited() throws {
+        let task = Process()
+        let clonedFD = dup(1)
+        task.executableURL = xdgTestHelperURL()
+        task.arguments = ["--print-open-file-descriptors"]
+        task.standardInput = FileHandle.nullDevice
+        let stdoutPipe = Pipe()
+        task.standardOutput = stdoutPipe.fileHandleForWriting
+        task.standardError = FileHandle.nullDevice
+        XCTAssertNoThrow(try task.run())
+
+        try task.run()
+        try stdoutPipe.fileHandleForWriting.close()
+        let stdoutData = try stdoutPipe.fileHandleForReading.readToEnd()
+        task.waitUntilExit()
+        print(String(decoding: stdoutData ?? Data(), as: Unicode.UTF8.self))
+        XCTAssertEqual("0\n1\n2\n", String(decoding: stdoutData ?? Data(), as: Unicode.UTF8.self))
+        close(clonedFD)
+    }
+
     static var allTests: [(String, (TestProcess) -> () throws -> Void)] {
         var tests = [
             ("test_exit0" , test_exit0),
@@ -779,6 +799,7 @@ class TestProcess : XCTestCase {
             ("test_currentDirectory", test_currentDirectory),
             ("test_pipeCloseBeforeLaunch", test_pipeCloseBeforeLaunch),
             ("test_multiProcesses", test_multiProcesses),
+            ("test_fileDescriptorsAreNotInherited", test_fileDescriptorsAreNotInherited),
         ]
 
 #if !os(Windows)

TestFoundation/xdgTestHelper/main.swift

@@ -196,6 +196,15 @@ func cat(_ args: ArraySlice<String>.Iterator) {
     exit(exitCode)
 }
 
+func printOpenFileDescriptors() {
+    for fd in 0..<getdtablesize() {
+        if fcntl(fd, F_GETFD) != -1 {
+            print(fd)
+        }
+    }
+    exit(0)
+}
+
 // -----
 
 var arguments = ProcessInfo.processInfo.arguments.dropFirst().makeIterator()
@@ -255,7 +264,10 @@ case "--nspathfor":
 case "--signal-test":
     signalTest()
 #endif
-    
+
+case "--print-open-file-descriptors":
+    printOpenFileDescriptors()
+
 default:
     fatalError("These arguments are not recognized. Only run this from a unit test.")
 }