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/****************************************************************
* *
* Copyright 2001, 2011 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#include "mdef.h"
#include "gtm_unistd.h"
#include "gtm_ipc.h"
#include "gtm_stdio.h"
#include <sys/sem.h>
#include <sys/shm.h>
#include <errno.h>
#include "gtm_sem.h"
#include "iosp.h"
#include "gtm_c_stack_trace.h"
#include "eintr_wrappers.h"
#include "eintr_wrapper_semop.h"
#include "ipcrmid.h"
#include "util.h"
#include "mupip_upgrade_standalone.h"
#include "gdsroot.h"
#include "gtm_facility.h"
#include "fileinfo.h"
#include "gdsbt.h"
#include "gdsfhead.h"
#include "filestruct.h"
/* Lock a file using semaphore.
* This is written so that we can use it to lock all database pre-V4.2000.
* Parameters:
* fn : database file name.
* semid: returns semaphore id. Caller may need to remove it.
* Return TRUE if successful.
* Else Return FALSE.
*/
boolean_t mupip_upgrade_standalone(char *fn, int *semid)
{
struct sembuf sop[4];
int key, semop_res, sems;
*semid = INVALID_SEMID;
if ((key = FTOK(fn, 1)) == -1) /* V3.2 and V4.0x had project id = 1 */
{
util_out_print("Error with ftok", TRUE);
return FALSE;
}
/* If shared memory exists, the disk file is probably incomplete */
if ((shmget(key, 0, 0) != -1) || errno != ENOENT)
{
util_out_print("File is locked by another user", TRUE);
return FALSE;
}
if ((sems = semget(key, FTOK_SEM_PER_ID, RWDALL | IPC_CREAT | IPC_NOWAIT)) == -1)
{
util_out_print("Error with semget", TRUE);
return FALSE;
}
/*
* Both semaphores must have value 0 and then all will be
* incremented to completely lockout any other potential users
* until we are done
*/
sop[0].sem_num = 0; sop[0].sem_op = 0; /* First check all semaphore have 0 value */
sop[1].sem_num = 1; sop[1].sem_op = 0;
sop[2].sem_num = 0; sop[2].sem_op = 1; /* Increment all semaphores */
sop[3].sem_num = 1; sop[3].sem_op = 1;
sop[0].sem_flg = sop[1].sem_flg = sop[2].sem_flg = sop[3].sem_flg = SEM_UNDO | IPC_NOWAIT;
SEMOP(sems, sop, 4, semop_res, NO_WAIT);
if (-1 == semop_res)
{
if (errno == EAGAIN)
{
util_out_print("File already open by another process", TRUE);
return FALSE;
}
util_out_print("Error with SEMOP", TRUE);
return FALSE;
}
/* See if someone built some shared memory in the time we were
* building semaphores. If so, we have failed */
if((shmget(key, 0, 0) != -1) || errno != ENOENT)
{
if (0 != sem_rmid(sems))
{
util_out_print("Error with sem_rmid", TRUE);
return FALSE;
}
util_out_print("File is locked by another user", TRUE);
return FALSE;
}
*semid = sems;
return TRUE;
}
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