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Make evdns_getaddrinfo_cancel threadsafe

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This commit is contained in:
Nick Mathewson 2010-11-19 12:14:18 -05:00
parent c7cfbcf466
commit d51b2fc655
1 changed files with 25 additions and 13 deletions
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38
evdns.c
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@ -4060,6 +4060,9 @@ struct evdns_getaddrinfo_request {
int pending_error;
/* If this is set, the user canceled this request. */
unsigned user_canceled : 1;
/* If this is set, the user can no longer cancel this request; we're
* just waiting for the free. */
unsigned request_done : 1;
};
/* Convert an evdns errors to the equivalent getaddrinfo error. */
@ -4189,29 +4192,32 @@ evdns_getaddrinfo_gotresolve(int result, char type, int count,
int socklen, addrlen;
void *addrp;
int err;
int user_canceled;
EVUTIL_ASSERT(req->type == DNS_IPv4_A || req->type == DNS_IPv6_AAAA);
if (req->type == DNS_IPv4_A) {
data = EVUTIL_UPCAST(req, struct evdns_getaddrinfo_request, ipv4_request);
other_req = &data->ipv6_request;
if (evdns_result_is_answer(result)) {
EVDNS_LOCK(data->evdns_base);
++data->evdns_base->getaddrinfo_ipv4_answered;
EVDNS_UNLOCK(data->evdns_base);
}
} else {
data = EVUTIL_UPCAST(req, struct evdns_getaddrinfo_request, ipv6_request);
other_req = &data->ipv4_request;
if (evdns_result_is_answer(result)) {
EVDNS_LOCK(data->evdns_base);
++data->evdns_base->getaddrinfo_ipv6_answered;
EVDNS_UNLOCK(data->evdns_base);
}
}
EVDNS_LOCK(data->evdns_base);
if (evdns_result_is_answer(result)) {
if (req->type == DNS_IPv4_A)
++data->evdns_base->getaddrinfo_ipv4_answered;
else
++data->evdns_base->getaddrinfo_ipv6_answered;
}
user_canceled = data->user_canceled;
if (other_req->r == NULL)
data->request_done = 1;
EVDNS_UNLOCK(data->evdns_base);
req->r = NULL;
if (result == DNS_ERR_CANCEL && ! data->user_canceled) {
if (result == DNS_ERR_CANCEL && ! user_canceled) {
/* Internal cancel request from timeout or internal error.
* we already answered the user. */
if (other_req->r == NULL)
@ -4239,7 +4245,7 @@ evdns_getaddrinfo_gotresolve(int result, char type, int count,
return;
}
if (data->user_canceled) {
if (user_canceled) {
data->user_cb(EVUTIL_EAI_CANCEL, NULL, data->user_data);
} else if (data->pending_result) {
/* If we have an answer waiting, and we weren't
@ -4255,7 +4261,7 @@ evdns_getaddrinfo_gotresolve(int result, char type, int count,
}
free_getaddrinfo_request(data);
return;
} else if (data->user_canceled) {
} else if (user_canceled) {
if (other_req->r) {
/* The other request is still working; let it hit this
* callback with EVUTIL_EAI_CANCEL callback and report
@ -4524,10 +4530,16 @@ evdns_getaddrinfo(struct evdns_base *dns_base,
void
evdns_getaddrinfo_cancel(struct evdns_getaddrinfo_request *data)
{
EVDNS_LOCK(data->evdns_base);
if (data->request_done) {
EVDNS_UNLOCK(data->evdns_base);
return;
}
event_del(&data->timeout);
data->user_canceled = 1;
if (data->ipv4_request.r)
evdns_cancel_request(data->evdns_base, data->ipv4_request.r);
if (data->ipv6_request.r)
evdns_cancel_request(data->evdns_base, data->ipv6_request.r);
EVDNS_UNLOCK(data->evdns_base);
}