[newlib-cygwin/main] Cygwin: Add a timeout to ensure we don't wait forever for dumper

[Jon Turney <jturney@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=1c13ca67b506df56c512d1a706eb6f45d9b4da38

commit 1c13ca67b506df56c512d1a706eb6f45d9b4da38
Author: Jon Turney <jon.turney@dronecode.org.uk>
Date:   Tue Jan 23 16:07:34 2024 +0000

    Cygwin: Add a timeout to ensure we don't wait forever for dumper

Diff:
---
 winsup/cygwin/exceptions.cc | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index 0e1a804ca..a2a6f9d4c 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -540,6 +540,9 @@ int exec_prepared_command (PWCHAR command)
     }
   FreeEnvironmentStringsW (rawenv);
 
+  /* timeout from waiting for debugger to attach after 10 seconds */
+  ULONGLONG timeout = GetTickCount64() + 10*1000;
+
   console_printf ("*** starting '%W' for pid %u, tid %u\r\n",
 		  command,
 		  cygwin_pid (GetCurrentProcessId ()), GetCurrentThreadId ());
@@ -562,7 +565,8 @@ int exec_prepared_command (PWCHAR command)
      we continue or not.
 
      Note that this is still racy: if the error_start process does it's work too
-     fast, we don't notice that it attached and get stuck here.
+     fast, we don't notice that it attached and get stuck here.  So we also
+     apply a timeout to ensure we exit eventually.
   */
 
   *dbg_end = L'\0';
@@ -570,7 +574,7 @@ int exec_prepared_command (PWCHAR command)
     system_printf ("Failed to start, %E");
   else
     {
-      while (!being_debugged ())
+      while (!being_debugged () && GetTickCount64() < timeout)
 	Sleep (0);
       Sleep (2000);
     }