bugfix: Fix compilation on FreeBSD. (#3625)

* Fix compilation on FreeBSD.
* Explicitly error out on unsupported platforms.
* Make the MAP_NORESERVE change specific for FreeBSD.
* Fix the sed expression to run on FreeBSD, too.
* Make the TestMain to run on all java versions on FreeBSD.
* Update the documentation for FreeBSD.
* Restore the ability to skip leading whitespaces in a more portable way.
* Add a note about failing tests.

(cherry picked from commit 963666d)

docs/user/setup.rst

@@ -93,15 +93,24 @@ installation of Arch Linux.
     $ sudo dnf groupinstall "Development Tools"
     $ sudo dnf install gc-devel zlib-devel # both optional
 
-**FreeBSD 12.2 and later**
+**FreeBSD 12.4 and later**
+
+*Note 1:* Only AMD64 and ARM64 architectures are supported.
+
+*Note 2:* Sufficiently recent versions of llvm and zlib come with the
+installation of FreeBSD.
 
 .. code-block:: shell
 
-    $ pkg install llvm10
     $ pkg install boehm-gc # optional
 
-*Note:* A version of zlib that is sufficiently recent comes with the
-installation of FreeBSD.
+*Note 3:* Using the boehm GC with multi-threaded binaries doesn't work
+out-of-the-box yet.
+
+*Note 4:* A number of tests, primarily unit-tests, are known to fail
+or not terminate on FreeBSD. It is believed that the code-under-test
+is correct and that the defect is in the test itself.
+Work is underway to fix these tests.
 
 **Nix/NixOS**
 

scripts/scalafmt

@@ -3,7 +3,7 @@
 set -e
 
 HERE="`dirname $0`"
-VERSION=$(sed -nre "s#\s*version[^0-9]+([0-9.]+)#\1#p" $HERE/../.scalafmt.conf)
+VERSION=$(sed -nre "s#[[:space:]]*version[^0-9]+([0-9.]+)#\1#p" $HERE/../.scalafmt.conf)
 COURSIER="$HERE/.coursier"
 SCALAFMT="$HERE/.scalafmt-$VERSION"
 

test-interface/src/main/scala/scala/scalanative/testinterface/TestMain.scala

@@ -28,56 +28,26 @@ object TestMain {
       |""".stripMargin
   }
 
-  final val iPv4Loopback = "127.0.0.1"
-  final val iPv6Loopback = "::1"
-
-  private def getFreeBSDLoopbackAddr(): String = {
+  private def setFreeBSDWorkaround(): Unit = {
     /* Standard out-of-the-box FreeBSD differs from Linux & macOS in
-     * not allowing IPv4 mapped IPv6 addresses, such as :FFFF:127.0.0.1
-     * or ::ffff:7f00:1.  These can be enabled by setting the line
-     * ipv6_ipv4mapping="YES" in /etc/rc.conf (and rebooting).
+     * not allowing IPv4-mapped IPv6 addresses, such as :FFFF:127.0.0.1
+     * or ::ffff:7f00:1.
      *
-     * FreeBSD TestMain initial connections should succeed on both IPv4
-     * and IPv6 systems without requiring arcane and non-standard system
-     * configuration.  This method checks the protocol that Java connect()
-     * is likely used and returns the corresponding loopback address.
-     * Tests which use IPv4 addresses, either through hard-coding or
-     * bind resolution, on IPv6 systems will still fail. This allows to
-     * run the vast majority of tests which do not have this characteristic.
+     * Another difference is that Java versions >= 11 on FreeBSD set
+     * java.net.preferIPv4Stack=true by default, so the sbt server
+     * listens only on a tcp4 socket.
      *
-     * Networking is complex, especially on j-random systems: full of
-     * joy & lamentation.
+     * Even if IPv4-mapped IPv6 addresses can be enabled (via the
+     * net.inet6.ip6.v6only=0 sysctl and/or via the ipv6_ipv4mapping="YES"
+     * rc.conf variable) and sbt can be instructed to listen on an IPv6
+     * socket (via the java.net.preferIPv4Stack=false system property),
+     * the easiest way to make TestMain to work on most FreeBSD machines,
+     * with different Java versions, is to set
+     * java.net.preferIPv4Stack=true in Scala Native, before the first
+     * Java network call, in order to always use an AF_INET IPv4 socket.
      */
 
-    if (!LinktimeInfo.isFreeBSD) iPv4Loopback // should never happen
-    else {
-      // These are the effective imports
-      import scalanative.posix.sys.socket._
-      import scalanative.posix.netinet.in
-      import scalanative.posix.unistd
-
-      /* These are to get this code to compile on Windows.
-       * Including all of them is cargo cult programming. Someone
-       * more patient or more knowledgeable about Windows may
-       * be able to reduce the set.
-       */
-      import scala.scalanative.windows._
-      import scala.scalanative.windows.WinSocketApi._
-      import scala.scalanative.windows.WinSocketApiExt._
-      import scala.scalanative.windows.WinSocketApiOps._
-      import scala.scalanative.windows.ErrorHandlingApi._
-
-      /* The keen observer will note that this scheme could be used
-       * for Linux and macOS. That change is not introduced at this time
-       * in order to preserve historical behavior.
-       */
-      val sd = socket(AF_INET6, SOCK_STREAM, in.IPPROTO_TCP)
-      if (sd == -1) iPv4Loopback
-      else {
-        unistd.close(sd)
-        iPv6Loopback
-      }
-    }
+    System.setProperty("java.net.preferIPv4Stack", "true")
   }
 
   /** Main method of the test runner. */
@@ -87,11 +57,9 @@ object TestMain {
       throw new IllegalArgumentException("One argument expected")
     }
 
-    val serverAddr =
-      if (!LinktimeInfo.isFreeBSD) iPv4Loopback
-      else getFreeBSDLoopbackAddr()
+    if (LinktimeInfo.isFreeBSD) setFreeBSDWorkaround()
     val serverPort = args(0).toInt
-    val clientSocket = new Socket(serverAddr, serverPort)
+    val clientSocket = new Socket("127.0.0.1", serverPort)
     val nativeRPC = new NativeRPC(clientSocket)(ExecutionContext.global)
     val bridge = new TestAdapterBridge(nativeRPC)