mir/bind
2
0
Fork 0
mirror of https://gitlab.isc.org/isc-projects/bind9 synced 2025-08-31 06:25:31 +00:00
Code Issues Releases Wiki Activity

Rework dbiterator implementation

Browse Source 
If the iterator is paused, the tree is unlocked and may change.

In an RBT tree it's always possible to resume iteration as long
as a valid node pointer was still held, but now that the underlying
database structure is a QP trie, the iterator needs to be initialized
based on the existing structure of the trie or it will return
inconsistent results. We now call dns_qp_lookup() to reinitialize
the QP iterator whenever dbiterator_next() or dbiterator_prev() is
called on a paused iterator.
This commit is contained in:
Matthijs Mekking
2024-02-07 14:52:59 +01:00
parent 6df391d610
commit cdf62a18e7
1 changed files with 62 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

91
lib/dns/qpdb.c
View File

@@ -277,8 +277,9 @@ typedef struct qpdb_dbiterator {
bool new_origin;
isc_rwlocktype_t tree_locked;
isc_result_t result;
dns_fixedname_t name;
dns_fixedname_t origin;
dns_fixedname_t fixed;
dns_name_t *name;
dns_qpiter_t iter;
dns_qpiter_t nsec3iter;
dns_qpiter_t *current;
@@ -2253,8 +2254,9 @@ dns__qpdb_createiterator(dns_db_t *db, unsigned int options,
qpdbiter->paused = true;
qpdbiter->tree_locked = isc_rwlocktype_none;
qpdbiter->result = ISC_R_SUCCESS;
dns_fixedname_init(&qpdbiter->name);
dns_fixedname_init(&qpdbiter->origin);
dns_fixedname_init(&qpdbiter->fixed);
qpdbiter->name = dns_fixedname_initname(&qpdbiter->fixed);
qpdbiter->node = NULL;
if ((options & DNS_DB_NSEC3ONLY) != 0) {
@@ -4167,7 +4169,7 @@ dereference_iter_node(qpdb_dbiterator_t *qpdbiter DNS__DB_FLARG) {
}
static void
resume_iteration(qpdb_dbiterator_t *qpdbiter) {
resume_iteration(qpdb_dbiterator_t *qpdbiter, bool continuing) {
dns_qpdb_t *qpdb = (dns_qpdb_t *)qpdbiter->common.db;
REQUIRE(qpdbiter->paused);
@@ -4175,6 +4177,28 @@ resume_iteration(qpdb_dbiterator_t *qpdbiter) {
TREE_RDLOCK(&qpdb->tree_lock, &qpdbiter->tree_locked);
/*
* If we're being called from dbiterator_next or _prev,
* then we may need to reinitialize the iterator to the current
* name. The tree could have changed while it was unlocked,
* would make the iterator traversal inconsistent.
*
* As long as the iterator is holding a reference to
* qpdbiter->node, the node won't be removed from the tree,
* so the lookup should always succeed.
*/
if (continuing && qpdbiter->node != NULL) {
isc_result_t result;
dns_qp_t *tree = qpdb->tree;
if (qpdbiter->current == &qpdbiter->nsec3iter) {
tree = qpdb->nsec3;
}
result = dns_qp_lookup(tree, qpdbiter->name, NULL,
qpdbiter->current, NULL, NULL, NULL);
INSIST(result == ISC_R_SUCCESS);
}
qpdbiter->paused = false;
}
@@ -4215,7 +4239,7 @@ dbiterator_first(dns_dbiterator_t *iterator DNS__DB_FLARG) {
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter);
resume_iteration(qpdbiter, false);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
@@ -4224,13 +4248,13 @@ dbiterator_first(dns_dbiterator_t *iterator DNS__DB_FLARG) {
case nsec3only:
qpdbiter->current = &qpdbiter->nsec3iter;
dns_qpiter_init(qpdb->nsec3, qpdbiter->current);
result = dns_qpiter_next(qpdbiter->current, NULL,
result = dns_qpiter_next(qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
if (result == ISC_R_SUCCESS || result == DNS_R_NEWORIGIN) {
/* If we're in the NSEC3 tree, skip the origin */
if (QPDBITER_NSEC3_ORIGIN_NODE(qpdb, qpdbiter)) {
result = dns_qpiter_next(
qpdbiter->current, NULL,
qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
}
}
@@ -4238,20 +4262,20 @@ dbiterator_first(dns_dbiterator_t *iterator DNS__DB_FLARG) {
case nonsec3:
qpdbiter->current = &qpdbiter->iter;
dns_qpiter_init(qpdb->tree, qpdbiter->current);
result = dns_qpiter_next(qpdbiter->current, NULL,
result = dns_qpiter_next(qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
break;
case full:
qpdbiter->current = &qpdbiter->iter;
dns_qpiter_init(qpdb->tree, qpdbiter->current);
result = dns_qpiter_next(qpdbiter->current, NULL,
result = dns_qpiter_next(qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
if (result == ISC_R_NOMORE) {
qpdbiter->current = &qpdbiter->nsec3iter;
dns_qpiter_init(qpdb->nsec3, qpdbiter->current);
result = dns_qpiter_next(qpdbiter->current, NULL,
(void **)&qpdbiter->node,
NULL);
result = dns_qpiter_next(
qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
}
break;
default:
@@ -4263,6 +4287,7 @@ dbiterator_first(dns_dbiterator_t *iterator DNS__DB_FLARG) {
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
INSIST(result == ISC_R_NOMORE); /* The tree is empty. */
qpdbiter->node = NULL;
}
qpdbiter->result = result;
@@ -4289,7 +4314,7 @@ dbiterator_last(dns_dbiterator_t *iterator DNS__DB_FLARG) {
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter);
resume_iteration(qpdbiter, false);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
@@ -4298,7 +4323,7 @@ dbiterator_last(dns_dbiterator_t *iterator DNS__DB_FLARG) {
case nsec3only:
qpdbiter->current = &qpdbiter->nsec3iter;
dns_qpiter_init(qpdb->nsec3, qpdbiter->current);
result = dns_qpiter_prev(qpdbiter->current, NULL,
result = dns_qpiter_prev(qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
if ((result == ISC_R_SUCCESS || result == DNS_R_NEWORIGIN) &&
QPDBITER_NSEC3_ORIGIN_NODE(qpdb, qpdbiter))
@@ -4313,13 +4338,13 @@ dbiterator_last(dns_dbiterator_t *iterator DNS__DB_FLARG) {
case nonsec3:
qpdbiter->current = &qpdbiter->iter;
dns_qpiter_init(qpdb->tree, qpdbiter->current);
result = dns_qpiter_prev(qpdbiter->current, NULL,
result = dns_qpiter_prev(qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
break;
case full:
qpdbiter->current = &qpdbiter->nsec3iter;
dns_qpiter_init(qpdb->nsec3, qpdbiter->current);
result = dns_qpiter_prev(qpdbiter->current, NULL,
result = dns_qpiter_prev(qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
if ((result == ISC_R_SUCCESS || result == DNS_R_NEWORIGIN) &&
QPDBITER_NSEC3_ORIGIN_NODE(qpdb, qpdbiter))
@@ -4333,9 +4358,9 @@ dbiterator_last(dns_dbiterator_t *iterator DNS__DB_FLARG) {
if (result == ISC_R_NOMORE) {
qpdbiter->current = &qpdbiter->iter;
dns_qpiter_init(qpdb->tree, qpdbiter->current);
result = dns_qpiter_prev(qpdbiter->current, NULL,
(void **)&qpdbiter->node,
NULL);
result = dns_qpiter_prev(
qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
}
break;
default:
@@ -4347,6 +4372,7 @@ dbiterator_last(dns_dbiterator_t *iterator DNS__DB_FLARG) {
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
INSIST(result == ISC_R_NOMORE); /* The tree is empty. */
qpdbiter->node = NULL;
}
qpdbiter->result = result;
@@ -4370,7 +4396,7 @@ dbiterator_seek(dns_dbiterator_t *iterator,
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter);
resume_iteration(qpdbiter, false);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
@@ -4415,6 +4441,7 @@ dbiterator_seek(dns_dbiterator_t *iterator,
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
qpdbiter->new_origin = true;
dns_name_copy(qpdbiter->node->name, qpdbiter->name);
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
qpdbiter->node = NULL;
@@ -4439,12 +4466,12 @@ dbiterator_prev(dns_dbiterator_t *iterator DNS__DB_FLARG) {
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter);
resume_iteration(qpdbiter, true);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
result = dns_qpiter_prev(qpdbiter->current, NULL,
result = dns_qpiter_prev(qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
if (qpdbiter->current == &qpdbiter->nsec3iter) {
@@ -4462,9 +4489,9 @@ dbiterator_prev(dns_dbiterator_t *iterator DNS__DB_FLARG) {
if (result == ISC_R_NOMORE && qpdbiter->nsec3mode == full) {
qpdbiter->current = &qpdbiter->iter;
dns_qpiter_init(qpdb->tree, qpdbiter->current);
result = dns_qpiter_prev(qpdbiter->current, NULL,
(void **)&qpdbiter->node,
NULL);
result = dns_qpiter_prev(
qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
}
}
@@ -4472,6 +4499,9 @@ dbiterator_prev(dns_dbiterator_t *iterator DNS__DB_FLARG) {
if (result == ISC_R_SUCCESS) {
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
INSIST(result == ISC_R_NOMORE);
qpdbiter->node = NULL;
}
qpdbiter->result = result;
@@ -4492,12 +4522,12 @@ dbiterator_next(dns_dbiterator_t *iterator DNS__DB_FLARG) {
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter);
resume_iteration(qpdbiter, true);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
result = dns_qpiter_next(qpdbiter->current, NULL,
result = dns_qpiter_next(qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
if (result == ISC_R_NOMORE && qpdbiter->nsec3mode == full &&
@@ -4505,7 +4535,7 @@ dbiterator_next(dns_dbiterator_t *iterator DNS__DB_FLARG) {
{
qpdbiter->current = &qpdbiter->nsec3iter;
dns_qpiter_init(qpdb->nsec3, qpdbiter->current);
result = dns_qpiter_next(qpdbiter->current, NULL,
result = dns_qpiter_next(qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
}
@@ -4519,7 +4549,7 @@ dbiterator_next(dns_dbiterator_t *iterator DNS__DB_FLARG) {
case nsec3only:
case full:
result = dns_qpiter_next(
qpdbiter->current, NULL,
qpdbiter->current, qpdbiter->name,
(void **)&qpdbiter->node, NULL);
break;
case nonsec3:
@@ -4536,6 +4566,9 @@ dbiterator_next(dns_dbiterator_t *iterator DNS__DB_FLARG) {
if (result == ISC_R_SUCCESS) {
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
INSIST(result == ISC_R_NOMORE);
qpdbiter->node = NULL;
}
qpdbiter->result = result;
@@ -4555,7 +4588,7 @@ dbiterator_current(dns_dbiterator_t *iterator, dns_dbnode_t **nodep,
REQUIRE(qpdbiter->node != NULL);
if (qpdbiter->paused) {
resume_iteration(qpdbiter);
resume_iteration(qpdbiter, false);
}
if (name != NULL) {