gcc/libjava/java/lang/natPosixProcess.cc

// natPosixProcess.cc - Native side of POSIX process code.

/* Copyright (C) 1998, 1999  Cygnus Solutions

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

#include <config.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#include <cni.h>
#include <jvm.h>

#include <java/lang/ConcreteProcess.h>
#include <java/lang/IllegalThreadStateException.h>
#include <java/lang/InterruptedException.h>
#include <java/lang/NullPointerException.h>
#include <java/lang/Thread.h>
#include <java/io/FileDescriptor.h>
#include <java/io/FileInputStream.h>
#include <java/io/FileOutputStream.h>
#include <java/io/IOException.h>

extern char **environ;

void
java::lang::ConcreteProcess::destroy (void)
{
  if (! hasExited)
    {
      // Really kill it.
      kill ((pid_t) pid, SIGKILL);
    }
}

jint
java::lang::ConcreteProcess::exitValue (void)
{
  if (! hasExited)
    {
      int wstat;
      pid_t r = waitpid ((pid_t) pid, &wstat, WNOHANG);
      if (r == -1)
	{
	  jstring x = JvNewStringLatin1 (strerror (errno));
	  _Jv_Throw (new IllegalThreadStateException (x));
	}

      hasExited = true;
      // Just use the raw status.  FIXME: what is right?
      status = wstat;
    }

  return status;
}

jint
java::lang::ConcreteProcess::waitFor (void)
{
  if (! hasExited)
    {
      int wstat;
      int r = waitpid ((pid_t) pid, &wstat, 0);

      if (r != -1)
	{
	  hasExited = true;
	  // Just use the raw status.  FIXME: what is right?
	  status = wstat;
	}

      if (java::lang::Thread::interrupted())
	_Jv_Throw (new InterruptedException (JvNewStringLatin1 ("wait interrupted")));
    }

  return status;
}

static char *
new_string (jstring string)
{
  jsize s = _Jv_GetStringUTFLength (string);
  char *buf = (char *) _Jv_Malloc (s + 1);
  _Jv_GetStringUTFRegion (string, 0, s, buf);
  buf[s] = '\0';
  return buf;
}

void
java::lang::ConcreteProcess::startProcess (jstringArray progarray,
					   jstringArray envp)
{
  using namespace java::io;

  hasExited = false;

  if (! progarray)
    _Jv_Throw (new NullPointerException);

  // Transform arrays to native form.
  // FIXME: we use malloc here.  We shouldn't.  If an exception is
  // thrown we will leak memory.
  char **args = (char **) _Jv_Malloc ((progarray->length + 1)
				      * sizeof (char *));
  char **env = NULL;

  // FIXME: GC will fail here if _Jv_Malloc throws an exception.
  // That's because we have to manually free the contents, but we 
  jstring *elts = elements (progarray);
  for (int i = 0; i < progarray->length; ++i)
    args[i] = new_string (elts[i]);
  args[progarray->length] = NULL;

  if (envp)
    {
      env = (char **) _Jv_Malloc ((envp->length + 1) * sizeof (char *));
      elts = elements (envp);
      for (int i = 0; i < envp->length; ++i)
	env[i] = new_string (elts[i]);
      env[envp->length] = NULL;
    }

  // Create pipes for I/O.
  int inp[2], outp[2], errp[2];

  if (pipe (inp)
      || pipe (outp)
      || pipe (errp))
    {
    ioerror:
      // FIXME.
      _Jv_Free (args);
      if (env)
	_Jv_Free (env);
      _Jv_Throw (new IOException (JvNewStringLatin1 (strerror (errno))));
    }

  // We create the streams before forking.  Otherwise if we had an
  // error while creating the streams we would have run the child with
  // no way to communicate with it.
  errorStream = new FileInputStream (new FileDescriptor (errp[0]));
  inputStream = new FileInputStream (new FileDescriptor (inp[0]));
  outputStream = new FileOutputStream (new FileDescriptor (outp[1]));

  // We don't use vfork() because that would cause the local
  // environment to be set by the child.
  if ((pid = (jlong) fork ()) == -1)
    goto ioerror;

  if (pid == 0)
    {
      // Child process, so remap descriptors and exec.

      if (envp)
        {
	  // preserve PATH unless specified explicitly
	  char *path_val = getenv("PATH");
	  environ = env;
	  if (getenv("PATH") == NULL)
	    {
	      char *path_env = (char *) _Jv_Malloc (strlen(path_val) + 5 + 1);
	      sprintf (path_env, "PATH=%s", path_val); 
	      putenv (path_env);
	    }
	}
	
      // We ignore errors from dup2 because they should never occur.
      dup2 (outp[0], 0);
      dup2 (inp[1], 1);
      dup2 (errp[1], 2);

      close (inp[0]);
      close (inp[1]);
      close (errp[0]);
      close (errp[1]);
      close (outp[0]);
      close (outp[1]);

      execvp (args[0], args);
      // FIXME: should throw an IOException if execvp() fails. Not trivial,
      // because _Jv_Throw won't work from child process
      _exit (127);
    }

  // Parent.  Close extra file descriptors and mark ours as
  // close-on-exec.
  close (outp[0]);
  close (inp[1]);
  close (errp[1]);

  fcntl (outp[1], F_SETFD, 1);
  fcntl (inp[0], F_SETFD, 1);
  fcntl (errp[0], F_SETFD, 1);
}