task scheduler manage at.exe tasks

Have you ever tried this:

C:\>cd WINDOWS
C:\WINDOWS>cd Tasks
C:\WINDOWS\Tasks>dir /a/s/b
C:\WINDOWS\Tasks\dfrag.job
C:\WINDOWS\Tasks\At1.job
C:\WINDOWS\Tasks\desktop.ini
C:\WINDOWS\Tasks\SA.DAT
C:\WINDOWS\Tasks\User_Task1.job

To delete this *.job files Just execute the following statement:

system("del /a /f C:\WINDOWS\Tasks\*.job");

Note: Please specify you OS dir. It is not always C:\windows.

erez_l wrote:

The big prblem is that I don't know exactly what is the structure of those at files and how to search inside them, because they are in the "control panel\scheduled tasks" folder.

You can easily dissect these files, MSDN has documentation on the file format.
See 2.4.1 FIXDLEN_DATA[^] and 2.4.2 Variable-Length Data Section[^]

You can probably skip the section 2.4.1 because it is fixed length and doesn't contain anything you are interested in.

What you might come up with is this.
It is the full code to a console application that will print the command line of every .job file.

#include <windows.h>
#include <stdio.h>
//Makes sure there is no padding added in by the compiler
#pragma pack(push)
#pragma pack(1)
//This struct is irrelevant for your task
typedef struct {
	WORD nProductVersion;
	WORD nFileVersion;
	WORD nUUID[9];
	WORD nAppNameLenOffset;
	WORD nTriggerOffset;
	WORD nErrorRetryCount;
	WORD nErrorRetryInterval;
	WORD nIdleDeadline;
	WORD nIdleWait;
	DWORD nPriority;
	DWORD nMaximumRunTime;
	DWORD nExitCode;
	DWORD nStatus;
	DWORD nFlags;
	WORD nYear;
	WORD nMonth;
	WORD nWeekday;
	WORD nDay;
	WORD nHour;
	WORD nMinute;
	WORD nSecond;
	WORD nMilliSeconds;
} FixedLenData;
typedef struct {
	WORD nLength;
	wchar_t szString[]; //0 sized array warning can be ignored
} UnicodeString;
typedef struct {
	FixedLenData *pHeader;
	union {
		struct {
			UnicodeString *pApplicationName; //The .exe name
			UnicodeString *pParameters; //The additional command line args
			UnicodeString *pRunningInstanceCount;
			UnicodeString *pWorkingDirectory;
			UnicodeString *pAuthor;
			UnicodeString *pComment;
			UnicodeString *pUserData;
			UnicodeString *pReservedData;
			UnicodeString *pTriggers;
			UnicodeString *pJobSignature;
		};
		UnicodeString *pStrings[10];
	};
} ATJobFile;
#pragma pack(pop)
ATJobFile *ReadJob(LPCSTR szFileName) {
	HANDLE hFile = CreateFile(szFileName, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
	if (hFile == INVALID_HANDLE_VALUE) {
		return NULL;
	}
	DWORD nFileSize = SetFilePointer(hFile, 0, NULL, FILE_END); //Get file size
	SetFilePointer(hFile, 0, NULL, FILE_BEGIN); //Reset file pointer
	BYTE *pData = new BYTE[nFileSize];
	ATJobFile *pJob = new ATJobFile();
	ReadFile(hFile, pData, nFileSize, &nFileSize, NULL);
	CloseHandle(hFile);
	pJob->pHeader = (FixedLenData *)pData; //This points to the start of the file
	pData += sizeof(FixedLenData);
	for (int nString = 0; nString < 10; ++nString) {
		pJob->pStrings[nString] = (UnicodeString *)pData;
		pData += pJob->pStrings[nString]->nLength * sizeof(wchar_t) + sizeof(WORD);
	}
	return pJob;
}
void DestroyJob(ATJobFile *pJob) {
	delete []pJob->pHeader;
	delete pJob;
}
int main() {
	WIN32_FIND_DATA fdSearch;
	char szWinDir[MAX_PATH];
	ExpandEnvironmentStrings("%WINDIR%\\Tasks", szWinDir, sizeof(szWinDir)); //Find the Windows directory
	SetCurrentDirectory(szWinDir); //This just saves us putting "C:\\Windows\\Tasks\\" infront of everything
	HANDLE hFind = FindFirstFile("*.job", &fdSearch);
	if (hFind != INVALID_HANDLE_VALUE) {
		do {
			ATJobFile *pJob = ReadJob(fdSearch.cFileName);
			printf("Job %s\n", fdSearch.cFileName);
			if (pJob->pParameters->nLength == NULL) {
				wprintf(L"%s\n\n", pJob->pApplicationName->szString);
			} else {
				wprintf(L"%s %s\n\n", pJob->pApplicationName->szString, pJob->pParameters->szString);
			}
			DestroyJob(pJob);
		} while (FindNextFile(hFind, &fdSearch));
	}
	return 0;
}

Schtasks.exe is a more recent tool than at.exe. With it you can create, query, run and delete tasks.

C:\Documents and Settings\dev\desktop>schtasks /query /fo LIST /v

HostName:                             GIRAFFE
TaskName:                             BCTEST
Next Run Time:                        Never
Status:
Last Run Time:                        20:39:00, 28/05/2009
Last Result:                          0
Creator:                              dev
Schedule:                             At 00:02 every day, starting 16/12/2009
Task To Run:                          E:\cmd\BCScript\RunBCScript.cmd
Start In:                             e:\cmd\bcscript
Comment:                              N/A
Scheduled Task State:                 Disabled
Scheduled Type:                       Daily
Start Time:                           00:02:00
Start Date:                           16/12/2009
End Date:                             N/A
Days:                                 Everyday
Months:                               N/A
Run As User:                          Could not be retrieved from the task scheduler database
Delete Task If Not Rescheduled:       Disabled
Stop Task If Runs X Hours and X Mins: 72:0
Repeat: Every:                        Disabled
Repeat: Until: Time:                  Disabled
Repeat: Until: Duration:              Disabled
Repeat: Stop If Still Running:        Disabled
Idle Time:                            Disabled
Power Management:                     No Start On Batteries, Stop On Battery Mode

Taskname is the name of the .job file minus the extension, in this example BCTEST and Task To Run is the command line "E:\cmd\BCScript\RunBCScript.cmd"

It would be a fairly simple operation to capture and parse the output to find the task(s) you want to delete.

Deletion is achieved using the command

C:\WINDOWS\Tasks>schtasks /delete /tn BCTEST /f
SUCCESS: The scheduled task "BCTEST" was successfully deleted.

Alan.