128 lines
3.7 KiB
C
128 lines
3.7 KiB
C
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/****************************************************************
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* *
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* Copyright 2001, 2004 Sanchez Computer Associates, 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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#ifdef VMS
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#include <ssdef.h>
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#endif
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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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#include "mlkdef.h"
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#include "lockdefs.h"
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#include "cmidef.h"
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#include "hashtab_mname.h" /* needed for cmmdef.h */
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#include "cmmdef.h"
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#include "gt_timer.h"
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#include "gtcmlkdef.h"
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#include "is_proc_alive.h"
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#include "gtcml.h"
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GBLREF gd_region *gv_cur_region;
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GBLREF uint4 process_id;
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GBLREF short crash_count;
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void gtcml_chklck(cm_lckblkreg *reg, bool timed)
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{
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cm_lckblklck *lck, *lckroot, *lcktofree;
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cm_lckblkprc *prc, *prc1;
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mlk_shrblk_ptr_t d;
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boolean_t stop_waking, timeout, was_crit;
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sgmnt_addrs *csa;
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int4 icount, status, time[2];
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timeout = TRUE;
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lckroot = reg->lock;
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lck = lckroot->next;
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lcktofree = NULL;
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/* it appears that the design assumes that lck should never be null, but we have empirical that it happens.
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* because we do not (at the moment of writing) have resources to pursue the discrepancy, we simply protect
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* against it, and hope that we don't encounter other symptoms
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*/
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while (lck != NULL)
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{
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if (timed)
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{
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if (timeout = gtcml_lcktime(lck))
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{
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prc = prc1 = lck->prc;
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if (prc)
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{ /* Check if blocking processes exists. */
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do
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{ /* Note that previous code in this section would manipulate the sequence
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numbers in the shared blocks rather than in the private blocks. This was
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deemed to not always be safe, especially in the case of parent/child
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locking since when a lock it held, the sequence number at its release
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MUST match the sequence number at it's inception or the lock cannot and
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will not be released by mlk_unlock. By always manipulating the sequence
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number in private storage instead, we avoid this problem totally. se 8/2001 */
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if ((d = prc1->blocked))
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{ /* Blocking process shrblk exists. Check it under crit lock */
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csa = &FILE_INFO(gv_cur_region)->s_addrs;
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if (!(was_crit = csa->now_crit))
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grab_crit(gv_cur_region);
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if (d->sequence != prc1->blk_sequence)
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{ /* Blocking structure no longer ours - do artificial wakeup */
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lck->sequence = csa->hdr->trans_hist.lock_sequence++;
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} else if (d->owner)
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{ /* Blocking struct still has owner. Check if alive */
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if (PROC_ALIVE(d, time, icount, status))
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{ /* process that owned lock has died, free lock */
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d->owner = 0;
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lck->sequence = csa->hdr->trans_hist.lock_sequence++;
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}
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} else
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{ /* No longer any owner (lke stole?). Wake up */
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lck->sequence = csa->hdr->trans_hist.lock_sequence++;
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}
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if (!was_crit)
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rel_crit(gv_cur_region);
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}
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prc1 = prc1->next;
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} while (prc1 != prc);
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}
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}
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}
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if (timeout)
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{
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gtcml_chkprc(lck);
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if (lck->prc == 0)
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{
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lck->next->last = lck->last;
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lck->last->next = lck->next;
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if (lck->next == lckroot && lck->last == lckroot)
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{ /* no more lcks for reg */
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reg->lock = 0;
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free(lck);
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free(lckroot); /* list header */
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break;
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}
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lcktofree = lck; /* not yet */
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}
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}
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lck = lck->next;
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if (NULL != lcktofree)
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{
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free(lcktofree);
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lcktofree = NULL;
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}
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if (lck == lckroot)
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break; /* at end of list */
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}
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}
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