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