configure.ac: look for the socket functions in libnetwork too

[duncanmcqueen]

Split from #60.

Problem and fix

On Haiku, the socket functions (socket, connect, inet_pton, gethostbyname and the others) and h_errno (__h_errno) are in libnetwork, not in libroot (the C library). configure.ac looks for inet_pton in the C library and in libnsl only. Thus on Haiku:

• configure does not find inet_pton and the other socket functions.
• The JNI libraries (libjavanio.so, libjavanet.so) do not link with libnetwork. They compile, but they do not load: Symbol not found. Each program stops at the start, because the VM cannot load libjavanio.so.

Now AC_SEARCH_LIBS for inet_pton also looks in libnetwork.

How to reproduce

On Haiku, with #74 and #75 (without them, master does not build on Haiku):

../configure --enable-jni ...
grep -n "containing inet_pton" config.log
make && make install
readelf -d <prefix>/lib/classpath/libjavanio.so | grep NEEDED

Then run this program:

javac NetBasics.java
java NetBasics

NetBasics.java

import java.io.*;
import java.net.*;
import java.util.*;

/**
 * Basic network operations: resolve a host name, list the network
 * interfaces, and connect a socket to a server socket on the loopback
 * interface. Each one loads Classpath's java-net JNI library.
 */
public class NetBasics
{
  public static void main(String[] args) throws Exception
  {
    try
      {
        System.out.println("resolve: " + InetAddress.getByName("localhost"));
        for (Enumeration<NetworkInterface> e =
               NetworkInterface.getNetworkInterfaces(); e.hasMoreElements(); )
          {
            NetworkInterface i = e.nextElement();
            System.out.println("interface: " + i.getName() + " up="
                               + i.isUp() + " loopback=" + i.isLoopback());
          }
        ServerSocket ss = new ServerSocket(0, 1, InetAddress.getByName("127.0.0.1"));
        Socket c = new Socket("127.0.0.1", ss.getLocalPort());
        Socket s = ss.accept();
        c.getOutputStream().write(42);
        int b = s.getInputStream().read();
        System.out.println((b == 42 ? "PASS" : "FAIL") + ": socket byte = " + b);
        System.exit(b == 42 ? 0 : 1);
      }
    catch (Throwable t)
      {
        System.out.println("FAIL: " + t);
        t.printStackTrace(System.out);
        System.exit(1);
      }
  }
}

Results

Haiku R1/beta6 x86_64 (hrev59866), javac from OpenJDK 8, Kaffe 1.1.10-pre. I ran autoreconf on Linux (autoconf 2.73, automake 1.19) and built on Haiku out of tree with --enable-jni --disable-examples --disable-plugin --disable-gjdoc --disable-gtk-peer --disable-gconf-peer --disable-alsa --disable-dssi.

Before (master with #74, #75, and #62, #64 and #65 for Kaffe):
checking for library containing inet_pton... no
libjavanio.so NEEDED: [libiconv.so.2] [libroot.so]
dlopen(libjavanio.so): Symbol not found
  (undefined, and defined in libnetwork.so: __h_errno accept bind connect gethostbyaddr
   gethostbyname getpeername getsockname getsockopt listen recv recvfrom send sendto
   setsockopt shutdown socket)
Kaffe:
java/lang/UnsatisfiedLinkError: Native library `javanio' not found (as file `libjavanio.so' in class loader null) ...
   at java.lang.ClassLoader.getSystemClassLoader (ClassLoader.java:799)
Abort

After (also with this pull request):
checking for library containing inet_pton... -lnetwork
libjavanio.so NEEDED: [libiconv.so.2] [libnetwork.so] [libroot.so]
dlopen(libjavanio.so): loaded
resolve: localhost/127.0.0.1
interface: /dev/net/ipro1000/0 up=true loopback=false
interface: loop up=true loopback=true
PASS: socket byte = 42

Platforms

Specific to Haiku (and BeOS, which also has libnetwork). AC_SEARCH_LIBS tries the libraries only when the function is not in the C library. On Linux, configure gives checking for library containing inet_pton... none required and checking how many arguments gethostbyname_r() takes... six, so it does not add -lnetwork on Linux.

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