Fix for leaking file descriptor issue

runtime/bin/process_linux.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_LINUX)
 
 #include "bin/process.h"
 
 #include <errno.h>  // NOLINT
@@ skipping 460 matching lines @@
         execvp(path, const_cast<char* const*>(program_arguments)));
 
     ReportChildError(exec_control[1]);
   }
 
   // The arguments and environment for the spawned process are not needed
   // any longer.
   delete[] program_arguments;
   delete[] program_environment;
 
-  int event_fds[2];
-  result = TEMP_FAILURE_RETRY(pipe(event_fds));
-  if (result < 0) {
-    SetChildOsErrorMessage(os_error_message);
-    TEMP_FAILURE_RETRY(close(read_in[0]));
-    TEMP_FAILURE_RETRY(close(read_in[1]));
-    TEMP_FAILURE_RETRY(close(read_err[0]));
-    TEMP_FAILURE_RETRY(close(read_err[1]));
-    TEMP_FAILURE_RETRY(close(write_out[0]));
-    TEMP_FAILURE_RETRY(close(write_out[1]));
-    Log::PrintErr("Error pipe creation failed: %s\n", *os_error_message);
-    return errno;
-  }
-  FDUtils::SetCloseOnExec(event_fds[0]);
-  FDUtils::SetCloseOnExec(event_fds[1]);
-
-  ProcessInfoList::AddProcess(pid, event_fds[1]);
-  *exit_event = event_fds[0];
-  FDUtils::SetNonBlocking(event_fds[0]);
-
   // Notify child process to start.
   char msg = '1';
   result = FDUtils::WriteToBlocking(read_in[1], &msg, sizeof(msg));
   if (result != sizeof(msg)) {
     perror("Failed sending notification message");
   }
 
   // Read exec result from child. If no data is returned the exec was
   // successful and the exec call closed the pipe. Otherwise the errno
   // is written to the pipe.
@@ skipping 20 matching lines @@
     TEMP_FAILURE_RETRY(close(read_in[0]));
     TEMP_FAILURE_RETRY(close(read_in[1]));
     TEMP_FAILURE_RETRY(close(read_err[0]));
     TEMP_FAILURE_RETRY(close(read_err[1]));
     TEMP_FAILURE_RETRY(close(write_out[0]));
     TEMP_FAILURE_RETRY(close(write_out[1]));
     if (bytes_read == -1) {
       return errno;  // Read failed.
     } else {
       return child_errno;  // Exec failed.
     }

[kustermann, 2013/06/03 07:30:27]

In these two cases, we return a nonzero value. The caller (i.e. Process_Start)
will then ignore the '*exit_event' fd.

   }
 
   FDUtils::SetNonBlocking(read_in[0]);
   *in = read_in[0];
   TEMP_FAILURE_RETRY(close(read_in[1]));
   FDUtils::SetNonBlocking(write_out[1]);
   *out = write_out[1];
   TEMP_FAILURE_RETRY(close(write_out[0]));
   FDUtils::SetNonBlocking(read_err[0]);
   *err = read_err[0];
   TEMP_FAILURE_RETRY(close(read_err[1]));
 
+  // Everything went well, so we can listen for the exitcode of our child
+  // process.
+  int event_fds[2];
+  result = TEMP_FAILURE_RETRY(pipe(event_fds));
+  if (result < 0) {
+    SetChildOsErrorMessage(os_error_message);
+    TEMP_FAILURE_RETRY(close(read_in[0]));
+    TEMP_FAILURE_RETRY(close(read_in[1]));
+    TEMP_FAILURE_RETRY(close(read_err[0]));
+    TEMP_FAILURE_RETRY(close(read_err[1]));
+    TEMP_FAILURE_RETRY(close(write_out[0]));
+    TEMP_FAILURE_RETRY(close(write_out[1]));
+    Log::PrintErr("Error pipe creation failed: %s\n", *os_error_message);
+    return errno;
+  }
+  FDUtils::SetCloseOnExec(event_fds[0]);
+  FDUtils::SetCloseOnExec(event_fds[1]);
+
+  ProcessInfoList::AddProcess(pid, event_fds[1]);
+  *exit_event = event_fds[0];
+  FDUtils::SetNonBlocking(event_fds[0]);
+
   *id = pid;
   return 0;
 }
 
 
 bool Process::Kill(intptr_t id, int signal) {
   return (TEMP_FAILURE_RETRY(kill(id, signal)) != -1);
 }
 
 
 void Process::TerminateExitCodeHandler() {
   ExitCodeHandler::TerminateExitCodeThread();
 }
 
 
 intptr_t Process::CurrentProcessId() {
   return static_cast<intptr_t>(getpid());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)