Write the server.pid file from C++ instead of Java.

This is because OsUtils.getpid() cannot work under msys2 since java.exe is not an msys2 binary. We might make it work by including JNI code, but the current plan is to go without JNI on Windows.

--
MOS_MIGRATED_REVID=120694746

2 files changed, 12 insertions, 11 deletions

diff --git a/src/main/cpp/blaze.cc b/src/main/cpp/blaze.cc
index cbcf4167e9..19e03ce4f7 100644
--- a/src/main/cpp/blaze.cc
+++ b/src/main/cpp/blaze.cc
@@ -546,13 +546,13 @@ static string VerifyJavaVersionAndGetJvm() {
 static int StartServer() {
   vector<string> jvm_args_vector = GetArgumentArray();
   string argument_string = GetArgumentString(jvm_args_vector);
-
+  string server_dir = globals->options.output_base + "/server";
   // Write the cmdline argument string to the server dir. If we get to this
   // point, there is no server running, so we don't overwrite the cmdline file
   // for the existing server. If might be that the server dies and the cmdline
   // file stays there, but that is not a problem, since we always check the
   // server, too.
-  WriteFile(argument_string, globals->options.output_base + "/server/cmdline");
+  WriteFile(argument_string, server_dir + "/cmdline");
 
   // unless we restarted for a new-version, mark this as initial start
   if (globals->restart_reason == NO_RESTART) {
@@ -581,6 +581,15 @@ static int StartServer() {
   }
 
   Daemonize();
+
+  // TODO(lberki): This writes the wrong PID on Windows because ExecuteProgram()
+  // invokes CreateProcess() there.
+  if (!WriteFile(ToString(getpid()), server_dir + "/server.pid")) {
+    // The exit code does not matter because we are already in the daemonized
+    // server. The output of this operation will end up in jvm.out .
+    pdie(0, "Cannot write PID file");
+  }
+
   ExecuteProgram(exe, jvm_args_vector);
   pdie(blaze_exit_code::INTERNAL_ERROR, "execv of '%s' failed", exe.c_str());
   return -1;
diff --git a/src/main/java/com/google/devtools/build/lib/server/RPCServer.java b/src/main/java/com/google/devtools/build/lib/server/RPCServer.java
index 6c6a8429ea..1997498209 100644
--- a/src/main/java/com/google/devtools/build/lib/server/RPCServer.java
+++ b/src/main/java/com/google/devtools/build/lib/server/RPCServer.java
@@ -15,8 +15,6 @@ package com.google.devtools.build.lib.server;
 
 import com.google.devtools.build.lib.runtime.CommandExecutor;
 import com.google.devtools.build.lib.util.Clock;
-import com.google.devtools.build.lib.util.OsUtils;
-import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 
 import java.io.IOException;
@@ -41,17 +39,11 @@ public abstract class RPCServer {
   }
 
   protected RPCServer(Path serverDirectory) throws IOException {
-    // We create the server.pid file strictly before binding the socket.
+    // server.pid was written in the C++ launcher after fork() but before exec() .
     // The client only accesses the pid file after connecting to the socket
     // which ensures that it gets the correct pid value.
     Path pidFile = serverDirectory.getRelative("server.pid");
     RPCServer.deleteAtExit(pidFile, /*deleteParent=*/ false);
-    try {
-      pidFile.delete();
-    } catch (IOException e) {
-      // Ignore.
-    }
-    FileSystemUtils.writeContentAsLatin1(pidFile, String.valueOf(OsUtils.getpid()));
   }
 
   /**