Windows: Wait for dumpcap to initialize.

As the MSDN documentation says, "CreateProcess returns without waiting
for the new process to finish its initialization." Add an SP_INIT sync
pipe indicator on Windows and use it in dumpcap to signal to its parent
that it has started up.

Change-Id: I88a4c158871dbe2dd6eba13434e92c5d4b1c2e4b
Reviewed-on: https://code.wireshark.org/review/15132
Reviewed-by: Gerald Combs <gerald@wireshark.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/dumpcap.c b/dumpcap.c
index 21230b7ec7..20389eaa0d 100644
--- a/dumpcap.c
+++ b/dumpcap.c
@@ -4131,6 +4131,8 @@ main(int argc, char *argv[])
                     exit_main(1);
                 }
             }
+            /* Let our parent know we're fully initialized. */
+            pipe_write_block(2, SP_INIT, "All systems go.");
 #endif
             break;