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a00f9e2f50
4224. [func] Added support for "dyndb", a new interface for loading zone data from an external database, developed by Red Hat for the FreeIPA project. DynDB drivers fully implement the BIND database API, and are capable of significantly better performance and functionality than DLZ drivers, while taking advantage of advanced database features not available in BIND such as multi-master replication. Thanks to Adam Tkac and Petr Spacek of Red Hat. [RT #35271]
56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
/*
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* Copyright (C) 2014-2015 Red Hat ; see COPYRIGHT for license
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*/
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#include <config.h>
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#include <isc/task.h>
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#include <isc/util.h>
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#include "lock.h"
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/*
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* Lock BIND dispatcher and allow only single task to run.
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*
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* @warning
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* All calls to isc_task_beginexclusive() have to operate on the same task
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* otherwise it would not be possible to distinguish recursive locking
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* from real conflict on the dispatcher lock.
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* For this reason this wrapper function always works with inst->task.
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* As a result, this function have to be be called only from inst->task.
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*
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* Recursive locking is allowed. Auxiliary variable pointed to by "statep"
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* stores information if last run_exclusive_enter() operation really locked
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* something or if the lock was called recursively and was no-op.
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*
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* The pair (inst, state) used for run_exclusive_enter() has to be
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* used for run_exclusive_exit().
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*
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* @param[in] inst The instance with the only task which is allowed to run.
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* @param[in,out] statep Lock state: ISC_R_SUCCESS or ISC_R_LOCKBUSY
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*/
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void
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run_exclusive_enter(sample_instance_t *inst, isc_result_t *statep) {
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REQUIRE(statep != NULL);
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REQUIRE(*statep == ISC_R_IGNORE);
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*statep = isc_task_beginexclusive(inst->task);
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RUNTIME_CHECK(*statep == ISC_R_SUCCESS || *statep == ISC_R_LOCKBUSY);
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}
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/*
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* Exit task-exclusive mode.
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*
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* @param[in] inst The instance used for previous run_exclusive_enter() call.
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* @param[in] state Lock state as returned by run_exclusive_enter().
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*/
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void
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run_exclusive_exit(sample_instance_t *inst, isc_result_t state) {
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if (state == ISC_R_SUCCESS)
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isc_task_endexclusive(inst->task);
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else
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/* Unlocking recursive lock or the lock was never locked. */
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INSIST(state == ISC_R_LOCKBUSY || state == ISC_R_IGNORE);
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return;
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}
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