2008.10.06
Suspend Windows from the Command Line
I used to leave my computer up all night, but I've come to realize that this is ecologically unsound. Now I suspend it before going to sleep, but this missed running a daily job that used to run at 03:00 am. The job marks my students' exercises and send me email with the next day's appointments. I thus decided to schedule the task to wakeup my computer at 3:00 am, run the job, and then suspend it again. The Windows scheduler allows you to specify a wakeup option, but not a subsequent suspend. Furthermore, it seems that Windows lacks a way to suspend from the command line (while maintaining the ability to hibernate), and the only free tools on the web are distributed in executable form, so I ended writing a small tool myself.
Here it is.
/*
* Command to force suspend a Windows computer.
* Compile with: cl suspend.c advapi32.lib
*
* Copyright (c) 2008, Diomidis Spinellis
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <stdio.h>
#include <windows.h>
/* Return as a string the error description for err */
static char *
wstrerror(LONG err)
{
static LPVOID lpMsgBuf;
if (lpMsgBuf)
LocalFree(lpMsgBuf);
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, err,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
(LPTSTR) &lpMsgBuf, 0, NULL);
return lpMsgBuf;
}
main()
{
HANDLE tok;
TOKEN_PRIVILEGES priv;
if (OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES |
TOKEN_QUERY, &tok) == 0) {
fprintf(stderr, "OpenProcessToken: %s\n",
wstrerror(GetLastError()));
return (1);
}
// Get the LUID for shutdown privilege.
if (LookupPrivilegeValue(NULL, SE_SHUTDOWN_NAME,
&priv.Privileges[0].Luid) == 0) {
fprintf(stderr, "LookupPrivilegeValue: %s\n",
wstrerror(GetLastError()));
return (1);
}
// Enable AdjustTokenPrivileges.
priv.PrivilegeCount = 1;
priv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
if (AdjustTokenPrivileges(tok, FALSE, &priv, 0, (PTOKEN_PRIVILEGES)NULL,
0) == 0 || GetLastError() != ERROR_SUCCESS) {
fprintf(stderr, "AdjustTokenPrivileges: %s\n",
wstrerror(GetLastError()));
return (1);
}
// Force suspend
if (SetSystemPowerState(TRUE, TRUE) == 0) {
fprintf(stderr, "SetSystemPowerState: %s\n",
wstrerror(GetLastError()));
return (1);
}
return (0);
}
