86 lines
3.1 KiB
C
86 lines
3.1 KiB
C
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/****************************************************************
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* *
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* Copyright 2001, 2010 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 <signal.h> /* for VSIG_ATOMIC_T type */
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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 "mutex.h"
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#include "deferred_signal_handler.h"
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#include "caller_id.h"
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#include "is_proc_alive.h"
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GBLREF volatile int4 crit_count;
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GBLREF uint4 process_id;
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GBLREF node_local_ptr_t locknl;
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GBLREF boolean_t hold_onto_locks;
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/* Note about usage of this function : Create dummy gd_region, gd_segment, file_control,
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* unix_db_info, sgmnt_addrs, and allocate mutex_struct (and NUM_CRIT_ENTRY * mutex_que_entry),
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* mutex_spin_parms_struct, and node_local in shared memory. Initialize the fields as in
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* jnlpool_init(). Pass the address of the dummy region as argument to this function.
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*/
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void grab_lock(gd_region *reg)
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{
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unix_db_info *udi;
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sgmnt_addrs *csa;
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enum cdb_sc status;
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mutex_spin_parms_ptr_t mutex_spin_parms;
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error_def(ERR_DBCCERR);
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error_def(ERR_CRITRESET);
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udi = FILE_INFO(reg);
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csa = &udi->s_addrs;
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assert(!hold_onto_locks && !csa->hold_onto_crit);
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if (!csa->now_crit)
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{
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assert(0 == crit_count);
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crit_count++; /* prevent interrupts */
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DEBUG_ONLY(locknl = csa->nl;) /* for DEBUG_ONLY LOCK_HIST macro */
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mutex_spin_parms = (mutex_spin_parms_ptr_t)((sm_uc_ptr_t)csa->critical + CRIT_SPACE);
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/* This assumes that mutex_spin_parms_t is located immediately after the crit structures */
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/* As of 10/07/98, crashcnt field in mutex_struct is not changed by any function for the dummy region */
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status = mutex_lockw(reg, mutex_spin_parms, 0);
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DEBUG_ONLY(locknl = NULL;) /* restore "locknl" to default value */
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if (status != cdb_sc_normal)
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{
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crit_count = 0;
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switch(status)
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{
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case cdb_sc_critreset: /* As of 10/07/98, this return value is not possible */
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rts_error(VARLSTCNT(4) ERR_CRITRESET, 2, REG_LEN_STR(reg));
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case cdb_sc_dbccerr:
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rts_error(VARLSTCNT(4) ERR_DBCCERR, 2, REG_LEN_STR(reg));
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default:
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GTMASSERT;
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}
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return;
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}
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/* There is only one case we know of when csa->nl->in_crit can be non-zero and that is when a process holding
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* crit gets kill -9ed and another process ends up invoking "secshr_db_clnup" which in turn clears the
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* crit semaphore (making it available for waiters) but does not also clear csa->nl->in_crit since it does not
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* hold crit at that point. But in that case, the pid reported in csa->nl->in_crit should be dead. Check that.
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*/
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assert((0 == csa->nl->in_crit) || (FALSE == is_proc_alive(csa->nl->in_crit, 0)));
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csa->nl->in_crit = process_id;
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CRIT_TRACE(crit_ops_gw); /* see gdsbt.h for comment on placement */
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crit_count = 0;
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}
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return;
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}
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