Add speculative support for OpenBSD. (#890)

OpenBSD has partial support in the Swift toolchain. This PR adds
speculative support for it based on the assumption that what works with
FreeBSD will generally also work with OpenBSD. The big differences:

1. We need to include `<util.h>` instead of `<libutil.h>`,
2. `/usr/bin/tar` does not support writing PKZIP files (so we look for
the optional `/usr/bin/zip` instead), and
3. OpenBSD has no way to determine the path to the current executable,
so we naïvely assume `argv[0]` is correct.

These changes are speculative and have not been tested.

Partially resolves #888.

### Checklist:

- [x] Code and documentation should follow the style of the [Style
Guide](https://github.com/apple/swift-testing/blob/main/Documentation/StyleGuide.md).
- [x] If public symbols are renamed or modified, DocC references should
be updated.

Author: grynspan

Documentation/Porting.md

@@ -256,7 +256,7 @@ platform conditional and provide a stub implementation:
 +++ b/Sources/Testing/Support/FileHandle.swift
 
  var isTTY: Bool {
- #if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(Android) || os(WASI)
+ #if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android) || os(WASI)
    // ...
 +#elseif os(Classic)
 +  return false

Package.swift

@@ -57,7 +57,7 @@ let package = Package(
       cxxSettings: .packageSettings,
       swiftSettings: .packageSettings,
       linkerSettings: [
-        .linkedLibrary("execinfo", .when(platforms: [.custom("freebsd")]))
+        .linkedLibrary("execinfo", .when(platforms: [.custom("freebsd"), .openbsd]))
       ]
     ),
     .testTarget(
@@ -127,7 +127,7 @@ let package = Package(
 )
 
 // BUG: swift-package-manager-#6367
-#if !os(Windows) && !os(FreeBSD)
+#if !os(Windows) && !os(FreeBSD) && !os(OpenBSD)
 package.targets.append(contentsOf: [
   .testTarget(
     name: "TestingMacrosTests",
@@ -156,7 +156,7 @@ extension Array where Element == PackageDescription.SwiftSetting {
 
       .define("SWT_NO_EXIT_TESTS", .when(platforms: [.iOS, .watchOS, .tvOS, .visionOS, .wasi, .android])),
       .define("SWT_NO_PROCESS_SPAWNING", .when(platforms: [.iOS, .watchOS, .tvOS, .visionOS, .wasi, .android])),
-      .define("SWT_NO_SNAPSHOT_TYPES", .when(platforms: [.linux, .custom("freebsd"), .windows, .wasi])),
+      .define("SWT_NO_SNAPSHOT_TYPES", .when(platforms: [.linux, .custom("freebsd"), .openbsd, .windows, .wasi])),
       .define("SWT_NO_DYNAMIC_LINKING", .when(platforms: [.wasi])),
       .define("SWT_NO_PIPES", .when(platforms: [.wasi])),
     ]
@@ -191,7 +191,7 @@ extension Array where Element == PackageDescription.CXXSetting {
     result += [
       .define("SWT_NO_EXIT_TESTS", .when(platforms: [.iOS, .watchOS, .tvOS, .visionOS, .wasi, .android])),
       .define("SWT_NO_PROCESS_SPAWNING", .when(platforms: [.iOS, .watchOS, .tvOS, .visionOS, .wasi, .android])),
-      .define("SWT_NO_SNAPSHOT_TYPES", .when(platforms: [.linux, .custom("freebsd"), .windows, .wasi])),
+      .define("SWT_NO_SNAPSHOT_TYPES", .when(platforms: [.linux, .custom("freebsd"), .openbsd, .windows, .wasi])),
       .define("SWT_NO_DYNAMIC_LINKING", .when(platforms: [.wasi])),
       .define("SWT_NO_PIPES", .when(platforms: [.wasi])),
     ]

Sources/Overlays/_Testing_Foundation/Attachments/Attachment+URL.swift

@@ -164,10 +164,23 @@ private func _compressContentsOfDirectory(at directoryURL: URL) async throws ->
   //
   // On Linux (which does not have FreeBSD's version of tar(1)), we can use
   // zip(1) instead.
+  //
+  // OpenBSD's tar(1) does not support writing PKZIP archives, and /usr/bin/zip
+  // tool is an optional install, so we check if it's present before trying to
+  // execute it.
 #if os(Linux)
   let archiverPath = "/usr/bin/zip"
 #elseif SWT_TARGET_OS_APPLE || os(FreeBSD)
   let archiverPath = "/usr/bin/tar"
+#elseif os(OpenBSD)
+  let archiverPath = "/usr/local/bin/zip"
+  var isDirectory = false
+  if !FileManager.default.fileExists(atPath: archiverPath, isDirectory: &isDirectory) || isDirectory {
+    throw CocoaError(.fileNoSuchFile, userInfo: [
+      NSLocalizedDescriptionKey: "The 'zip' package is not installed.",
+      NSFilePathErrorKey: archiverPath
+    ])
+  }
 #elseif os(Windows)
   guard let archiverPath = _archiverPath else {
     throw CocoaError(.fileWriteUnknown, userInfo: [
@@ -187,7 +200,7 @@ private func _compressContentsOfDirectory(at directoryURL: URL) async throws ->
 
     let sourcePath = directoryURL.fileSystemPath
     let destinationPath = temporaryURL.fileSystemPath
-#if os(Linux)
+#if os(Linux) || os(OpenBSD)
     // The zip command constructs relative paths from the current working
     // directory rather than from command-line arguments.
     process.arguments = [destinationPath, "--recurse-paths", "."]

Sources/Testing/ABI/EntryPoints/EntryPoint.swift

@@ -656,7 +656,7 @@ extension Event.ConsoleOutputRecorder.Options {
   /// Whether or not the system terminal claims to support 16-color ANSI escape
   /// codes.
   private static var _terminalSupports16ColorANSIEscapeCodes: Bool {
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(Android)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android)
     if let termVariable = Environment.variable(named: "TERM") {
       return termVariable != "dumb"
     }
@@ -678,7 +678,7 @@ extension Event.ConsoleOutputRecorder.Options {
   /// Whether or not the system terminal claims to support 256-color ANSI escape
   /// codes.
   private static var _terminalSupports256ColorANSIEscapeCodes: Bool {
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(Android)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android)
     if let termVariable = Environment.variable(named: "TERM") {
       return strstr(termVariable, "256") != nil
     }
@@ -700,7 +700,7 @@ extension Event.ConsoleOutputRecorder.Options {
   /// Whether or not the system terminal claims to support true-color ANSI
   /// escape codes.
   private static var _terminalSupportsTrueColorANSIEscapeCodes: Bool {
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(Android)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android)
     if let colortermVariable = Environment.variable(named: "COLORTERM") {
       return strstr(colortermVariable, "truecolor") != nil
     }

Sources/Testing/ABI/EntryPoints/SwiftPMEntryPoint.swift

@@ -24,7 +24,7 @@ private import _TestingInternals
 ///
 /// This constant is not part of the public interface of the testing library.
 var EXIT_NO_TESTS_FOUND: CInt {
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(Android) || os(WASI)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android) || os(WASI)
   EX_UNAVAILABLE
 #elseif os(Windows)
   CInt(ERROR_NOT_FOUND)

Sources/Testing/Events/Recorder/Event.Symbol.swift

@@ -106,7 +106,7 @@ extension Event.Symbol {
   /// be used to represent it in text-based output. The value of this property
   /// is platform-dependent.
   public var unicodeCharacter: Character {
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(Android) || os(WASI)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android) || os(WASI)
     switch self {
     case .default:
       // Unicode: WHITE DIAMOND

Sources/Testing/ExitTests/ExitCondition.swift

@@ -49,12 +49,13 @@ public enum ExitCondition: Sendable {
   /// | macOS | [`<stdlib.h>`](https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/_Exit.3.html), [`<sysexits.h>`](https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/sysexits.3.html) |
   /// | Linux | [`<stdlib.h>`](https://sourceware.org/glibc/manual/latest/html_node/Exit-Status.html), `<sysexits.h>` |
   /// | FreeBSD | [`<stdlib.h>`](https://man.freebsd.org/cgi/man.cgi?exit(3)), [`<sysexits.h>`](https://man.freebsd.org/cgi/man.cgi?sysexits(3)) |
+  /// | OpenBSD | [`<stdlib.h>`](https://man.openbsd.org/exit.3), [`<sysexits.h>`](https://man.openbsd.org/sysexits.3) |
   /// | Windows | [`<stdlib.h>`](https://learn.microsoft.com/en-us/cpp/c-runtime-library/exit-success-exit-failure) |
   ///
-  /// On macOS, FreeBSD, and Windows, the full exit code reported by the process
-  /// is yielded to the parent process. Linux and other POSIX-like systems may
-  /// only reliably report the low unsigned 8 bits (0&ndash;255) of the exit
-  /// code.
+  /// On macOS, FreeBSD, OpenBSD, and Windows, the full exit code reported by
+  /// the process is yielded to the parent process. Linux and other POSIX-like
+  /// systems may only reliably report the low unsigned 8 bits (0&ndash;255) of
+  /// the exit code.
   case exitCode(_ exitCode: CInt)
 
   /// The process terminated with the given signal.
@@ -70,6 +71,7 @@ public enum ExitCondition: Sendable {
   /// | macOS | [`<signal.h>`](https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/signal.3.html) |
   /// | Linux | [`<signal.h>`](https://sourceware.org/glibc/manual/latest/html_node/Standard-Signals.html) |
   /// | FreeBSD | [`<signal.h>`](https://man.freebsd.org/cgi/man.cgi?signal(3)) |
+  /// | OpenBSD | [`<signal.h>`](https://man.openbsd.org/signal.3) |
   /// | Windows | [`<signal.h>`](https://learn.microsoft.com/en-us/cpp/c-runtime-library/signal-constants) |
   case signal(_ signal: CInt)
 }

Sources/Testing/ExitTests/ExitTest.swift

@@ -110,9 +110,9 @@ extension ExitTest {
     // SEE: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/coredump.c#n610
     var rl = rlimit(rlim_cur: 1, rlim_max: 1)
     _ = setrlimit(CInt(RLIMIT_CORE.rawValue), &rl)
-#elseif os(FreeBSD)
-    // As with Linux, disable the generation core files. FreeBSD does not, as
-    // far as I can tell, special-case RLIMIT_CORE=1.
+#elseif os(FreeBSD) || os(OpenBSD)
+    // As with Linux, disable the generation core files. The BSDs do not, as far
+    // as I can tell, special-case RLIMIT_CORE=1.
     var rl = rlimit(rlim_cur: 0, rlim_max: 0)
     _ = setrlimit(RLIMIT_CORE, &rl)
 #elseif os(Windows)
@@ -152,6 +152,14 @@ extension ExitTest {
     }
 #endif
 
+#if os(OpenBSD)
+    // OpenBSD does not have posix_spawn_file_actions_addclosefrom_np().
+    // However, it does have closefrom(2), which we call here as a best effort.
+    if let from = Environment.variable(named: "SWT_CLOSEFROM").flatMap(CInt.init) {
+      _ = closefrom(from)
+    }
+#endif
+
     do {
       try await body()
     } catch {
@@ -344,7 +352,7 @@ extension ExitTest {
     }
 
     var fd: CInt?
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD)
     fd = CInt(backChannelEnvironmentVariable)
 #elseif os(Windows)
     if let handle = UInt(backChannelEnvironmentVariable).flatMap(HANDLE.init(bitPattern:)) {
@@ -541,7 +549,7 @@ extension ExitTest {
         // known environment variable to the corresponding file descriptor
         // (HANDLE on Windows.)
         var backChannelEnvironmentVariable: String?
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD)
         backChannelEnvironmentVariable = backChannelWriteEnd.withUnsafePOSIXFileDescriptor { fd in
           fd.map(String.init(describing:))
         }

Sources/Testing/ExitTests/SpawnProcess.swift

@@ -17,7 +17,7 @@ internal import _TestingInternals
 
 /// A platform-specific value identifying a process running on the current
 /// system.
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD)
 typealias ProcessID = pid_t
 #elseif os(Windows)
 typealias ProcessID = HANDLE
@@ -62,13 +62,13 @@ func spawnExecutable(
 ) throws -> ProcessID {
   // Darwin and Linux differ in their optionality for the posix_spawn types we
   // use, so use this typealias to paper over the differences.
-#if SWT_TARGET_OS_APPLE || os(FreeBSD)
+#if SWT_TARGET_OS_APPLE || os(FreeBSD) || os(OpenBSD)
   typealias P<T> = T?
 #elseif os(Linux)
   typealias P<T> = T
 #endif
 
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD)
   return try withUnsafeTemporaryAllocation(of: P<posix_spawn_file_actions_t>.self, capacity: 1) { fileActions in
     let fileActions = fileActions.baseAddress!
     guard 0 == posix_spawn_file_actions_init(fileActions) else {
@@ -105,9 +105,7 @@ func spawnExecutable(
       }
 
       // Forward standard I/O streams and any explicitly added file handles.
-#if os(Linux) || os(FreeBSD)
-      var highestFD = CInt(-1)
-#endif
+      var highestFD = max(STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO)
       func inherit(_ fileHandle: borrowing FileHandle, as standardFD: CInt? = nil) throws {
         try fileHandle.withUnsafePOSIXFileDescriptor { fd in
           guard let fd else {
@@ -118,9 +116,8 @@ func spawnExecutable(
           } else {
 #if SWT_TARGET_OS_APPLE
             _ = posix_spawn_file_actions_addinherit_np(fileActions, fd)
-#elseif os(Linux) || os(FreeBSD)
-            highestFD = max(highestFD, fd)
 #endif
+            highestFD = max(highestFD, fd)
           }
         }
       }
@@ -156,6 +153,12 @@ func spawnExecutable(
       // `swt_posix_spawn_file_actions_addclosefrom_np` to guard the
       // availability of this function.
       _ = posix_spawn_file_actions_addclosefrom_np(fileActions, highestFD + 1)
+#elseif os(OpenBSD)
+      // OpenBSD does not have posix_spawn_file_actions_addclosefrom_np().
+      // However, it does have closefrom(2), which we can call from within the
+      // spawned child process if we control its execution.
+      var environment = environment
+      environment["SWT_CLOSEFROM"] = String(describing: highestFD + 1)
 #else
 #warning("Platform-specific implementation missing: cannot close unused file descriptors")
 #endif

Sources/Testing/ExitTests/WaitFor.swift

@@ -11,7 +11,7 @@
 #if !SWT_NO_PROCESS_SPAWNING
 internal import _TestingInternals
 
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD)
 /// Block the calling thread, wait for the target process to exit, and return
 /// a value describing the conditions under which it exited.
 ///
@@ -78,14 +78,14 @@ func wait(for pid: consuming pid_t) async throws -> ExitCondition {
 
   return try _blockAndWait(for: pid)
 }
-#elseif SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD)
+#elseif SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD)
 /// A mapping of awaited child PIDs to their corresponding Swift continuations.
 private let _childProcessContinuations = Locked<[pid_t: CheckedContinuation<ExitCondition, any Error>]>()
 
 /// A condition variable used to suspend the waiter thread created by
 /// `_createWaitThread()` when there are no child processes to await.
 private nonisolated(unsafe) let _waitThreadNoChildrenCondition = {
-#if os(FreeBSD)
+#if os(FreeBSD) || os(OpenBSD)
   let result = UnsafeMutablePointer<pthread_cond_t?>.allocate(capacity: 1)
 #else
   let result = UnsafeMutablePointer<pthread_cond_t>.allocate(capacity: 1)
@@ -136,7 +136,7 @@ private let _createWaitThread: Void = {
 
   // Create the thread. It will run immediately; because it runs in an infinite
   // loop, we aren't worried about detaching or joining it.
-#if SWT_TARGET_OS_APPLE || os(FreeBSD)
+#if SWT_TARGET_OS_APPLE || os(FreeBSD) || os(OpenBSD)
   var thread: pthread_t?
 #else
   var thread = pthread_t()
@@ -147,14 +147,16 @@ private let _createWaitThread: Void = {
     { _ in
       // Set the thread name to help with diagnostics. Note that different
       // platforms support different thread name lengths. See MAXTHREADNAMESIZE
-      // on Darwin, TASK_COMM_LEN on Linux, and MAXCOMLEN on FreeBSD. We try to
-      // maximize legibility in the available space.
+      // on Darwin, TASK_COMM_LEN on Linux, MAXCOMLEN on FreeBSD, and _MAXCOMLEN
+      // on OpenBSD. We try to maximize legibility in the available space.
 #if SWT_TARGET_OS_APPLE
       _ = pthread_setname_np("Swift Testing exit test monitor")
 #elseif os(Linux)
       _ = swt_pthread_setname_np(pthread_self(), "SWT ExT monitor")
 #elseif os(FreeBSD)
       _ = pthread_set_name_np(pthread_self(), "SWT ex test monitor")
+#elseif os(OpenBSD)
+      _ = pthread_set_name_np(pthread_self(), "SWT exit test monitor")
 #else
 #warning("Platform-specific implementation missing: thread naming unavailable")
 #endif

Sources/Testing/SourceAttribution/Backtrace+Symbolication.swift

@@ -71,7 +71,7 @@ extension Backtrace {
         result[i] = SymbolicatedAddress(address: address, offset: offset, symbolName: symbolName)
       }
     }
-#elseif os(Linux) || os(FreeBSD) || os(Android)
+#elseif os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android)
     // Although these platforms have dladdr(), they do not have symbol names
     // from DWARF binaries by default, only from shared libraries. The standard
     // library's backtracing functionality has implemented sufficient ELF/DWARF

Sources/Testing/SourceAttribution/Backtrace.swift

@@ -69,7 +69,7 @@ public struct Backtrace: Sendable {
       initializedCount = addresses.withMemoryRebound(to: UnsafeMutableRawPointer.self) { addresses in
         .init(clamping: backtrace(addresses.baseAddress!, .init(clamping: addresses.count)))
       }
-#elseif os(Linux) || os(FreeBSD)
+#elseif os(Linux) || os(FreeBSD) || os(OpenBSD)
       initializedCount = .init(clamping: backtrace(addresses.baseAddress!, .init(clamping: addresses.count)))
 #elseif os(Windows)
       initializedCount = Int(clamping: RtlCaptureStackBackTrace(0, ULONG(clamping: addresses.count), addresses.baseAddress!, nil))
@@ -181,7 +181,7 @@ extension Backtrace {
     ///   crash. To avoid said crash, we'll keep a strong reference to the
     ///   object (abandoning memory until the process exits.)
     ///   ([swift-#62985](https://github.com/swiftlang/swift/issues/62985))
-#if os(Windows) || os(FreeBSD)
+#if os(Windows) || os(FreeBSD) || os(OpenBSD)
     nonisolated(unsafe) var errorObject: AnyObject?
 #else
     nonisolated(unsafe) weak var errorObject: AnyObject?

Sources/Testing/Support/Additions/CommandLineAdditions.swift

@@ -55,6 +55,14 @@ extension CommandLine {
           return String(cString: buffer.baseAddress!)
         }
       }
+#elseif os(OpenBSD)
+      // OpenBSD does not have API to get a path to the running executable. Use
+      // arguments[0]. We do a basic sniff test for a path-like string, but
+      // otherwise return argv[0] verbatim.
+      guard let argv0 = arguments.first, argv0.contains("/") else {
+        throw CError(rawValue: ENOEXEC)
+      }
+      return argv0
 #elseif os(Windows)
       var result: String?
 #if DEBUG
@@ -87,7 +95,7 @@ extension CommandLine {
       return arguments[0]
 #else
 #warning("Platform-specific implementation missing: executable path unavailable")
-      return ""
+      throw SystemError(description: "The executable path of the current process could not be determined.")
 #endif
     }
   }

Sources/Testing/Support/CError.swift

@@ -47,8 +47,8 @@ func strerror(_ errorCode: CInt) -> String {
     _ = strerror_s(buffer.baseAddress!, buffer.count, errorCode)
     return strnlen(buffer.baseAddress!, buffer.count)
   }
-#elseif os(FreeBSD)
-  // FreeBSD's implementation of strerror() is not thread-safe.
+#elseif os(FreeBSD) || os(OpenBSD)
+  // FreeBSD's/OpenBSD's implementation of strerror() is not thread-safe.
   String(unsafeUninitializedCapacity: 1024) { buffer in
     _ = strerror_r(errorCode, buffer.baseAddress!, buffer.count)
     return strnlen(buffer.baseAddress!, buffer.count)

Sources/Testing/Support/Environment.swift

@@ -42,7 +42,7 @@ enum Environment {
     }
   }
 
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(Android) || os(WASI)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android) || os(WASI)
   /// Get all environment variables from a POSIX environment block.
   ///
   /// - Parameters:
@@ -103,7 +103,7 @@ enum Environment {
     }
 #endif
     return _get(fromEnviron: _NSGetEnviron()!.pointee!)
-#elseif os(Linux) || os(FreeBSD) || os(Android)
+#elseif os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android)
     _get(fromEnviron: swt_environ())
 #elseif os(WASI)
     _get(fromEnviron: __wasilibc_get_environ())
@@ -170,7 +170,7 @@ enum Environment {
       }
       return nil
     }
-#elseif SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(Android) || os(WASI)
+#elseif SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android) || os(WASI)
     getenv(name).flatMap { String(validatingCString: $0) }
 #elseif os(Windows)
     name.withCString(encodedAs: UTF16.self) { name in