re PR libgcj/29324 (add wait handling hook)

	PR libgcj/29324
	* include/posix-threads.h (_Jv_BlockSigchld): Declare.
	(_Jv_UnBlockSigchld): Same.
	* posix-threads.cc: Include posix-threads.h.
	(block_sigchld) Rename to...
	(_Jv_BlockSigchld) ... this.
	(_Jv_UnBlockSigchld): New function.
	(_Jv_InitThreads): Call _Jv_BlockSigchld in place of block_sigchld.
	(_Jv_ThreadStart): Same.
	* java/lang/PosixProcess$ProcessManager.h: Regenerate.
	* java/lang/PosixProcess.java: Clean up imports.
	(ProcessManager): Make final.
	(ProcessManager.queue): Genericise and make private.
	(ProcessManager.pidToProcess): Remove.
	(ProcessManager.liveProcesses): New field.
	(ProcessManager.reaperPID): Remove.
	(ProcessManager.nativeData): New field.
	(ProcessManager.removeProcessFromMap): Remove.
	(ProcessManager.addProcessToMap):Remove.
	(ProcessManager.addToLiveProcesses): New method.
	(ProcessManager.run): Rewritten.
	(ProcessManager.reap): Change method signature,
	(getErrorStream): Correct formatting.
	(getInputStream): Same.
	(spawn): Add process to liveProcesses list.
	(pid): Make package private.
	* java/lang/PosixProcess.h: Regenerate.
	* java/lang/natPosixProcess.cc: Include posix.h and posix-threads.h.
	Add useing namespace java::lang.
	(ProcessManagerInternal): New struct.
	(sigchld_handler): Rewritten.
	(init): Rewritten.
	(waitForSignal): Same.
	(reap): Same.
	(signalReaper): Same.
	(nativeDestroy): Call kill as ::kill.
	(nativeSpawn): Correct formatting.
	* classpath/lib/java/lang/PosixProcess$EOFInputStream.class: Regenerate.
	* classpath/lib/java/lang/PosixProcess.class: Same.
	* classpath/lib/java/lang/PosixProcess$ProcessManager.class: Same.

From-SVN: r124638

1 files changed, 85 insertions, 72 deletions

diff --git a/libjava/java/lang/natPosixProcess.cc b/libjava/java/lang/natPosixProcess.cc
index 252da6e..c7b8b6e 100644
--- a/libjava/java/lang/natPosixProcess.cc
+++ b/libjava/java/lang/natPosixProcess.cc
@@ -30,6 +30,8 @@ details.  */
 
 #include <gcj/cni.h>
 #include <jvm.h>
+#include <posix.h>
+#include <posix-threads.h>
 
 #include <java/lang/PosixProcess$ProcessManager.h>
 #include <java/lang/PosixProcess.h>
@@ -48,6 +50,7 @@ details.  */
 #include <java/lang/PosixProcess$EOFInputStream.h>
 
 using gnu::java::nio::channels::FileChannelImpl;
+using namespace java::lang;
 
 extern char **environ;
 
@@ -91,13 +94,37 @@ myclose (int &fd)
   fd = -1;
 }
 
+namespace
+{
+  struct ProcessManagerInternal
+  {
+    int pipe_ends[2];
+    struct sigaction old_sigaction;
+  };
+}
+
+
 // There has to be a signal handler in order to be able to
 // sigwait() on SIGCHLD.  The information passed is ignored as it
 // will be recovered by the waitpid() call.
 static void
-sigchld_handler (int)
+sigchld_handler (int sig, siginfo_t *si, void *third)
 {
-  // Ignore.
+  if (PosixProcess$ProcessManager::nativeData != NULL)
+    {
+      ProcessManagerInternal *pmi =
+        (ProcessManagerInternal *)PosixProcess$ProcessManager::nativeData;
+      char c = 0;
+      ::write(pmi->pipe_ends[1], &c, 1);
+      if (pmi->old_sigaction.sa_handler != SIG_DFL
+          && pmi->old_sigaction.sa_handler != SIG_IGN)
+        {
+          if ((pmi->old_sigaction.sa_flags & SA_SIGINFO) != 0)
+            pmi->old_sigaction.sa_sigaction(sig, si, third);
+          else
+            (*pmi->old_sigaction.sa_handler)(sig);
+        }
+    }
 }
 
 
@@ -105,22 +132,35 @@ sigchld_handler (int)
 void
 java::lang::PosixProcess$ProcessManager::init ()
 {
-  using namespace java::lang;
-  // Remenber our PID so other threads can kill us.
-  reaperPID = (jlong) pthread_self ();
+  // The nativeData is static to avoid races installing the signal
+  // handler in the case that it is chained.
+  if (nativeData == NULL )
+    {
+      ProcessManagerInternal *pmi =
+        (ProcessManagerInternal *)JvAllocBytes(sizeof(ProcessManagerInternal));
 
-  // SIGCHLD is blocked in all threads in posix-threads.cc.
-  // Setup the SIGCHLD handler.
-  struct sigaction sa;
-  memset (&sa, 0, sizeof (sa));
+      if (0 != ::pipe(pmi->pipe_ends))
+        goto error;
 
-  sa.sa_handler = sigchld_handler;
-  // We only want signals when the things exit.
-  sa.sa_flags = SA_NOCLDSTOP;
+      // Make writing non-blocking so that the signal handler will
+      // never block.
+      int fl = ::fcntl(pmi->pipe_ends[1], F_GETFL);
+      ::fcntl(pmi->pipe_ends[1], F_SETFL, fl | O_NONBLOCK);
 
-  if (-1 == sigaction (SIGCHLD, &sa, NULL))
-    goto error;
+      nativeData = (::gnu::gcj::RawDataManaged *)pmi;
 
+      // SIGCHLD is blocked in all threads in posix-threads.cc.
+      // Setup the SIGCHLD handler.
+      struct sigaction sa;
+      memset (&sa, 0, sizeof (sa));
+
+      sa.sa_sigaction = sigchld_handler;
+      // We only want signals when the things exit.
+      sa.sa_flags = SA_NOCLDSTOP | SA_SIGINFO;
+
+      if (-1 == sigaction (SIGCHLD, &sa, &pmi->old_sigaction))
+        goto error;
+    }
   // All OK.
   return;
 
@@ -132,79 +172,52 @@ void
 java::lang::PosixProcess$ProcessManager::waitForSignal ()
 {
   // Wait for SIGCHLD
-  sigset_t mask;
-  pthread_sigmask (0, NULL, &mask);
-  sigdelset (&mask, SIGCHLD);
+  _Jv_UnBlockSigchld();
+  ProcessManagerInternal *pmi = (ProcessManagerInternal *)nativeData;
 
-  // Use sigsuspend() instead of sigwait() as sigwait() doesn't play
-  // nicely with the GC's use of signals.
-  sigsuspend (&mask);
+  // Try to read multiple (64) notifications in one go.
+  char c[64];
+ ::read(pmi->pipe_ends[0], c, sizeof (c));
 
-  // Do not check sigsuspend return value.  The only legitimate return
-  // is EINTR, but there is a known kernel bug affecting alpha-linux
-  // wrt sigsuspend+handler+sigreturn that can result in a return value
-  // of __NR_sigsuspend and errno unset.  Don't fail unnecessarily on
-  // older kernel versions.
+  _Jv_BlockSigchld();
 
-  // All OK.
   return;
 }
 
-jboolean java::lang::PosixProcess$ProcessManager::reap ()
+jboolean java::lang::PosixProcess$ProcessManager::reap (PosixProcess *p)
 {
-  using namespace java::lang;
-
-  pid_t pid;
-
-  for (;;)
-    {
-      // Get the return code from a dead child process.
-      int status;
-      pid = waitpid ((pid_t) - 1, &status, WNOHANG);
-      if (pid == -1)
-	{
-	  if (errno == ECHILD)
-	    return false;
-	  else
-	    goto error;
-	}
-
-      if (pid == 0)
-        return true;   // No children to wait for.
-
-      // Look up the process in our pid map.
-      PosixProcess * process = removeProcessFromMap ((jlong) pid);
-
-      // Note that if process==NULL, then we have an unknown child.
-      // This is not common, but can happen, and isn't an error.
-      if (process)
-	{
-	  JvSynchronize sync (process);
-	  process->status = WIFEXITED (status) ? WEXITSTATUS (status) : -1;
-	  process->state = PosixProcess::STATE_TERMINATED;
-          process->processTerminationCleanup();
-	  process->notifyAll ();
-	}
-    }
-
-error:
-  throw new InternalError (JvNewStringUTF (strerror (errno)));
+  pid_t rv;
+
+  // Try to get the return code from the child process.
+  int status;
+  rv = ::waitpid ((pid_t)p->pid, &status, WNOHANG);
+  if (rv == -1)
+    throw new InternalError (JvNewStringUTF (strerror (errno)));
+
+  if (rv == 0)
+    return false;   // No children to wait for.
+
+  JvSynchronize sync (p);
+  p->status = WIFEXITED (status) ? WEXITSTATUS (status) : -1;
+  p->state = PosixProcess::STATE_TERMINATED;
+  p->processTerminationCleanup();
+  p->notifyAll ();
+  return true;
 }
 
 void
 java::lang::PosixProcess$ProcessManager::signalReaper ()
 {
-  int c = pthread_kill ((pthread_t) reaperPID, SIGCHLD);
-  if (c == 0)
-    return;
-  // pthread_kill() failed.
-  throw new InternalError (JvNewStringUTF (strerror (c)));
+  ProcessManagerInternal *pmi = (ProcessManagerInternal *)nativeData;
+  char c = 0;
+  ::write(pmi->pipe_ends[1], &c, 1);
+  // Ignore errors.  If EPIPE the reaper has already exited.
 }
 
 void
 java::lang::PosixProcess::nativeDestroy ()
 {
-  int c = kill ((pid_t) pid, SIGKILL);
+  int c = ::kill ((pid_t) pid, SIGKILL);
   if (c == 0)
     return;
   // kill() failed.
@@ -427,9 +440,9 @@ java::lang::PosixProcess::nativeSpawn ()
       char c;
       int r = read (msgp[0], &c, 1);
       if (r == -1)
-      throw new IOException (JvNewStringUTF (strerror (errno)));
+        throw new IOException (JvNewStringUTF (strerror (errno)));
       else if (r != 0)
-      throw new IOException (JvNewStringUTF (strerror (c)));
+        throw new IOException (JvNewStringUTF (strerror (c)));
     }
   catch (java::lang::Throwable *thrown)
     {