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			11 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			389 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /* Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
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| 
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|    This program is free software; you can redistribute it and/or modify
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|    it under the terms of the GNU General Public License as published by
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|    the Free Software Foundation; version 2 of the License.
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| 
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|    This program is distributed in the hope that it will be useful,
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|    but WITHOUT ANY WARRANTY; without even the implied warranty of
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|    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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|    GNU General Public License for more details.
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| 
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|    You should have received a copy of the GNU General Public License
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|    along with this program; if not, write to the Free Software
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|    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
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| 
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| 
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| /*
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|   Utility program that encapsulates process creation, monitoring
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|   and bulletproof process cleanup
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| 
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|   Usage:
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|     safe_process [options to safe_process] -- progname arg1 ... argn
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| 
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|   To safeguard mysqld you would invoke safe_process with a few options
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|   for safe_process itself followed by a double dash to indicate start
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|   of the command line for the program you really want to start
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| 
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|   $> safe_process --output=output.log -- mysqld --datadir=var/data1 ...
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| 
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|   This would redirect output to output.log and then start mysqld,
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|   once it has done that it will continue to monitor the child as well
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|   as the parent.
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| 
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|   The safe_process then checks the follwing things:
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|   1. Child exits, propagate the childs return code to the parent
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|      by exiting with the same return code as the child.
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| 
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|   2. Parent dies, immediately kill the child and exit, thus the
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|      parent does not need to properly cleanup any child, it is handled
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|      automatically.
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| 
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|   3. Signal's recieced by the process will trigger same action as 2)
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| 
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|   4. The named event "safe_process[pid]" can be signaled and will
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|      trigger same action as 2)
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| 
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|   WARNING! Be careful when using ProcessExplorer, since it will open
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|            a handle to each process(and maybe also the Job), the process
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|            spawned by safe_process will not be closed off when safe_process
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|            is killed.
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| */
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| 
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| #include <windows.h>
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| #include <stdio.h>
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| #include <tlhelp32.h>
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| #include <signal.h>
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| #include <stdlib.h>
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| 
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| static int verbose= 0;
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| static char safe_process_name[32]= {0};
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| 
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| static void message(const char* fmt, ...)
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| {
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|   if (!verbose)
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|     return;
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|   va_list args;
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|   fprintf(stderr, "%s: ", safe_process_name);
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|   va_start(args, fmt);
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|   vfprintf(stderr, fmt, args);
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|   fprintf(stderr, "\n");
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|   va_end(args);
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|   fflush(stderr);
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| }
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| 
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| 
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| static void die(const char* fmt, ...)
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| {
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|   int last_err= GetLastError();
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|   va_list args;
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|   fprintf(stderr, "%s: FATAL ERROR, ", safe_process_name);
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|   va_start(args, fmt);
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|   vfprintf(stderr, fmt, args);
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|   fprintf(stderr, "\n");
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|   va_end(args);
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|   if (last_err)
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|   {
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|     char *message_text;
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|     if (FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER
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|         |FORMAT_MESSAGE_IGNORE_INSERTS, NULL, last_err , 0, (LPSTR)&message_text,
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|         0, NULL))
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|     {
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|       fprintf(stderr,"error: %d, %s\n",last_err, message_text);
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|       LocalFree(message_text);
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|     }
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|     else
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|     {
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|       /* FormatMessage failed, print error code only */
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|       fprintf(stderr,"error:%d\n", last_err);
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|     }
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|   }
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|   fflush(stderr);
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|   exit(1);
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| }
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| 
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| 
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| DWORD get_parent_pid(DWORD pid)
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| {
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|   HANDLE snapshot;
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|   DWORD parent_pid= 0;
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|   PROCESSENTRY32 pe32;
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|   pe32.dwSize= sizeof(PROCESSENTRY32);
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| 
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|   snapshot= CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
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|   if (snapshot == INVALID_HANDLE_VALUE)
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|     die("CreateToolhelp32Snapshot failed");
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| 
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|   if (!Process32First(snapshot, &pe32))
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|   {
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|     CloseHandle(snapshot);
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|     die("Process32First failed");
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|   }
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| 
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|   do
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|   {
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|     if (pe32.th32ProcessID == pid)
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|       parent_pid= pe32.th32ParentProcessID;
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|   } while(Process32Next( snapshot, &pe32));
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|   CloseHandle(snapshot);
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| 
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|   if (parent_pid == 0)
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|     die("Could not find parent pid");
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| 
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|   return parent_pid;
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| }
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| 
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| 
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| enum {
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|   PARENT,
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|   CHILD,
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|   EVENT,
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|   NUM_HANDLES
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| };
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| 
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| 
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| HANDLE shutdown_event;
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| void handle_signal (int signal)
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| {
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|   message("Got signal: %d", signal);
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|   if(SetEvent(shutdown_event) == 0) {
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|     /* exit safe_process and (hopefully) kill off the child */
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|     die("Failed to SetEvent");
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|   }
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| }
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| 
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| 
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| int main(int argc, const char** argv )
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| {
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|   char child_args[4096]= {0};
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|   DWORD pid= GetCurrentProcessId();
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|   DWORD parent_pid= get_parent_pid(pid);
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|   HANDLE job_handle;
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|   HANDLE wait_handles[NUM_HANDLES]= {0};
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|   PROCESS_INFORMATION process_info= {0};
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|   BOOL nocore= FALSE;
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| 
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|   sprintf(safe_process_name, "safe_process[%lu]", pid);
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| 
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|   /* Create an event for the signal handler */
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|   if ((shutdown_event=
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|        CreateEvent(NULL, TRUE, FALSE, safe_process_name)) == NULL)
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|     die("Failed to create shutdown_event");
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|   wait_handles[EVENT]= shutdown_event;
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| 
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|   signal(SIGINT,   handle_signal);
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|   signal(SIGBREAK, handle_signal);
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|   signal(SIGTERM,  handle_signal);
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| 
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|   message("Started");
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| 
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|   /* Parse arguments */
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|   for (int i= 1; i < argc; i++) {
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|     const char* arg= argv[i];
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| 	char* to= child_args;
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|     if (strcmp(arg, "--") == 0 && strlen(arg) == 2) {
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|       /* Got the "--" delimiter */
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|       if (i >= argc)
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|         die("No real args -> nothing to do");
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|       /* Copy the remaining args to child_arg */
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|       for (int j= i+1; j < argc; j++) {
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|         arg= argv[j];
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|         if (strchr (arg, ' ') &&
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|             arg[0] != '\"' &&
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|             arg[strlen(arg)] != '\"')
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|         {
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|           /* Quote arg that contains spaces and are not quoted already */
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|           to+= _snprintf(to, child_args + sizeof(child_args) - to,
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|                          "\"%s\" ", arg);
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|         }
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|         else
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|         {
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|           to+= _snprintf(to, child_args + sizeof(child_args) - to,
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|           "%s ", arg);
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|         }
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|       }
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|       break;
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|     } else {
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|       if (strcmp(arg, "--verbose") == 0)
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|         verbose++;
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|       else if (strncmp(arg, "--parent-pid", 12) == 0)
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|       {
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|             /* Override parent_pid with a value provided by user */
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|         const char* start;
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|         if ((start= strstr(arg, "=")) == NULL)
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|           die("Could not find start of option value in '%s'", arg);
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|         start++; /* Step past = */
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|         if ((parent_pid= atoi(start)) == 0)
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|           die("Invalid value '%s' passed to --parent-id", start);
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|       }
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|       else if (strcmp(arg, "--nocore") == 0)
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|       {
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|         nocore= TRUE;
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|       }
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|       else if ( strncmp (arg, "--env ", 6) == 0 )
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|       {
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| 	putenv(strdup(arg+6));
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|       }
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|       else
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|         die("Unknown option: %s", arg);
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|     }
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|   }
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|   if (*child_args == '\0')
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|     die("nothing to do");
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| 
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|   /* Open a handle to the parent process */
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|   message("parent_pid: %d", parent_pid);
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|   if (parent_pid == pid)
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|     die("parent_pid is equal to own pid!");
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| 
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|   if ((wait_handles[PARENT]=
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|        OpenProcess(SYNCHRONIZE, FALSE, parent_pid)) == NULL)
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|     die("Failed to open parent process with pid: %d", parent_pid);
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| 
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|   /* Create the child process in a job */
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|   JOBOBJECT_EXTENDED_LIMIT_INFORMATION jeli = { 0 };
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|   STARTUPINFO                          si   = { 0 };
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|   si.cb = sizeof(si);
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| 
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|   /*
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|     Create the job object to make it possible to kill the process
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|     and all of it's children in one go
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|   */
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|   if ((job_handle= CreateJobObject(NULL, NULL)) == NULL)
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|     die("CreateJobObject failed");
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| 
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|   /*
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|     Make all processes associated with the job terminate when the
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|     last handle to the job is closed.
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|   */
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| #ifndef JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE
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| #define JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE  0x00002000
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| #endif
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| 
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|   jeli.BasicLimitInformation.LimitFlags = JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE;
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|   if (SetInformationJobObject(job_handle, JobObjectExtendedLimitInformation,
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|                               &jeli, sizeof(jeli)) == 0)
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|     message("SetInformationJobObject failed, continue anyway...");
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| 
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| 				/* Avoid popup box */
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|   if (nocore)
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|     SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX
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|                  | SEM_NOOPENFILEERRORBOX);
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| 
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| #if 0
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|   /* Setup stdin, stdout and stderr redirect */
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|   si.dwFlags= STARTF_USESTDHANDLES;
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|   si.hStdInput= GetStdHandle(STD_INPUT_HANDLE);
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|   si.hStdOutput= GetStdHandle(STD_OUTPUT_HANDLE);
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|   si.hStdError= GetStdHandle(STD_ERROR_HANDLE);
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| #endif
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| 
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|   /*
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|     Create the process suspended to make sure it's assigned to the
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|     Job before it creates any process of it's own
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| 
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|     Allow the new process to break away from any job that this
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|     process is part of so that it can be assigned to the new JobObject
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|     we just created. This is safe since the new JobObject is created with
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|     the JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, making sure it will be
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|     terminated when the last handle to it is closed(which is owned by
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|     this process).
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| 
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|     If breakaway from job fails on some reason, fallback is to create a
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|     new process group. Process groups also allow to kill process and its 
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|     descedants, subject to some restrictions (processes have to run within
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|     the same console,and must not ignore CTRL_BREAK)
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|   */
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|   DWORD create_flags[]= {CREATE_BREAKAWAY_FROM_JOB, CREATE_NEW_PROCESS_GROUP, 0};
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|   BOOL process_created= FALSE;
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|   BOOL jobobject_assigned= FALSE;
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| 
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|   for (size_t i=0; i < sizeof(create_flags)/sizeof(create_flags[0]); i++)
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|   { 
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|     process_created= CreateProcess(NULL, (LPSTR)child_args,
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|                     NULL,
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|                     NULL,
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|                     TRUE, /* inherit handles */
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|                     CREATE_SUSPENDED | create_flags[i],
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|                     NULL,
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|                     NULL,
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|                     &si,
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|                     &process_info);
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|     if (process_created)
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|     {
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|      jobobject_assigned= AssignProcessToJobObject(job_handle, process_info.hProcess);
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|      break;
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|     }
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|   }
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| 
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|   if (!process_created)
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|   {
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|     die("CreateProcess failed");
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|   }
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|   ResumeThread(process_info.hThread);
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|   CloseHandle(process_info.hThread);
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| 
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|   wait_handles[CHILD]= process_info.hProcess;
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| 
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|   message("Started child %d", process_info.dwProcessId);
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| 
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|   /* Monitor loop */
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|   DWORD child_exit_code= 1;
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|   DWORD wait_res= WaitForMultipleObjects(NUM_HANDLES, wait_handles,
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|                                          FALSE, INFINITE);
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|   switch (wait_res)
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|   {
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|     case WAIT_OBJECT_0 + PARENT:
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|       message("Parent exit");
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|       break;
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|     case WAIT_OBJECT_0 + CHILD:
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|       if (GetExitCodeProcess(wait_handles[CHILD], &child_exit_code) == 0)
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|         message("Child exit: could not get exit_code");
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|       else
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|         message("Child exit: exit_code: %d", child_exit_code);
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|       break;
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|     case WAIT_OBJECT_0 + EVENT:
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|       message("Wake up from shutdown_event");
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|       break;
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| 
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|     default:
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|       message("Unexpected result %d from WaitForMultipleObjects", wait_res);
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|       break;
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|   }
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|   message("Exiting, child: %d", process_info.dwProcessId);
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| 
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|   if (TerminateJobObject(job_handle, 201) == 0)
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|     message("TerminateJobObject failed");
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|   CloseHandle(job_handle);
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|   message("Job terminated and closed");
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| 
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| 
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| 
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|   if (wait_res != WAIT_OBJECT_0 + CHILD)
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|   {
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|     if (!jobobject_assigned)
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|     {
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|       TerminateProcess(process_info.hProcess, 202);
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|     }
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|     /* The child has not yet returned, wait for it */
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|     message("waiting for child to exit");
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|     if ((wait_res= WaitForSingleObject(wait_handles[CHILD], INFINITE))
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|         != WAIT_OBJECT_0)
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|     {
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|       message("child wait failed: %d", wait_res);
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|     }
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|     else
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|     {
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|       message("child wait succeeded");
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|     }
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|     /* Child's exit code should now be 201, no need to get it */
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|   }
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| 
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|   message("Closing handles");
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|   for (int i= 0; i < NUM_HANDLES; i++)
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|     CloseHandle(wait_handles[i]);
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| 
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|   message("Exiting, exit_code: %d", child_exit_code);
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|   exit(child_exit_code);
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| }
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| 
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