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authorStefan Bühler <buehler@teamviewer.com>2015-03-17 09:09:43 +0100
committerDaniel Stenberg <daniel@haxx.se>2015-04-03 16:46:14 +0200
commit0db831976e4b2d2553c8cd9aaae492970d830f57 (patch)
tree7914cc2feee038d76edc740bffa838fb2ccd6628
parent369430cd170432446da245ee65d1edabedcd09f5 (diff)
fix refreshing of obsolete dns cache entries
- cache entries must be also refreshed when they are in use - have the cache count as inuse reference too, freeing timestamp == 0 special value - use timestamp == 0 for CURLOPT_RESOLVE entries which don't get refreshed - remove CURLOPT_RESOLVE special inuse reference (timestamp == 0 will prevent refresh) - fix Curl_hostcache_clean - CURLOPT_RESOLVE entries don't have a special reference anymore, and it would also release non CURLOPT_RESOLVE references - fix locking in Curl_hostcache_clean - fix unit1305.c: hash now keeps a reference, need to set inuse = 1
-rw-r--r--lib/hostip.c70
-rw-r--r--lib/hostip.h7
-rw-r--r--tests/unit/unit1305.c1
3 files changed, 36 insertions, 42 deletions
diff --git a/lib/hostip.c b/lib/hostip.c
index dc06e89f7..05f3ed0b5 100644
--- a/lib/hostip.c
+++ b/lib/hostip.c
@@ -137,10 +137,6 @@ struct curl_hash *Curl_global_host_cache_init(void)
void Curl_global_host_cache_dtor(void)
{
if(host_cache_initialized) {
- /* first make sure that any custom "CURLOPT_RESOLVE" names are
- cleared off */
- Curl_hostcache_clean(NULL, &hostname_cache);
- /* then free the remaining hash completely */
Curl_hash_clean(&hostname_cache);
host_cache_initialized = 0;
}
@@ -234,7 +230,8 @@ hostcache_timestamp_remove(void *datap, void *hc)
(struct hostcache_prune_data *) datap;
struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;
- return !c->inuse && (data->now - c->timestamp >= data->cache_timeout);
+ return (0 != c->timestamp)
+ && (data->now - c->timestamp >= data->cache_timeout);
}
/*
@@ -288,10 +285,9 @@ remove_entry_if_stale(struct SessionHandle *data, struct Curl_dns_entry *dns)
{
struct hostcache_prune_data user;
- if(!dns || (data->set.dns_cache_timeout == -1) || !data->dns.hostcache ||
- dns->inuse)
+ if(!dns || (data->set.dns_cache_timeout == -1) || !data->dns.hostcache)
/* cache forever means never prune, and NULL hostcache means we can't do
- it, if it still is in use then we leave it */
+ it */
return 0;
time(&user.now);
@@ -395,11 +391,11 @@ Curl_cache_addr(struct SessionHandle *data,
return NULL;
}
- dns->inuse = 0; /* init to not used */
+ dns->inuse = 1; /* the cache has the first reference */
dns->addr = addr; /* this is the address(es) */
time(&dns->timestamp);
if(dns->timestamp == 0)
- dns->timestamp = 1; /* zero indicates that entry isn't in hash table */
+ dns->timestamp = 1; /* zero indicates CURLOPT_RESOLVE entry */
/* Store the resolved data in our DNS cache. */
dns2 = Curl_hash_add(data->dns.hostcache, entry_id, entry_len+1,
@@ -717,35 +713,27 @@ clean_up:
*/
void Curl_resolv_unlock(struct SessionHandle *data, struct Curl_dns_entry *dns)
{
- DEBUGASSERT(dns && (dns->inuse>0));
-
if(data && data->share)
Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
- dns->inuse--;
- /* only free if nobody is using AND it is not in hostcache (timestamp ==
- 0) */
- if(dns->inuse == 0 && dns->timestamp == 0) {
- Curl_freeaddrinfo(dns->addr);
- free(dns);
- }
+ freednsentry(dns);
if(data && data->share)
Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
}
/*
- * File-internal: free a cache dns entry.
+ * File-internal: release cache dns entry reference, free if inuse drops to 0
*/
static void freednsentry(void *freethis)
{
- struct Curl_dns_entry *p = (struct Curl_dns_entry *) freethis;
+ struct Curl_dns_entry *dns = (struct Curl_dns_entry *) freethis;
+ DEBUGASSERT(dns && (dns->inuse>0));
- /* mark the entry as not in hostcache */
- p->timestamp = 0;
- if(p->inuse == 0) {
- Curl_freeaddrinfo(p->addr);
- free(p);
+ dns->inuse--;
+ if(dns->inuse == 0) {
+ Curl_freeaddrinfo(dns->addr);
+ free(dns);
}
}
@@ -757,13 +745,10 @@ struct curl_hash *Curl_mk_dnscache(void)
return Curl_hash_alloc(7, Curl_hash_str, Curl_str_key_compare, freednsentry);
}
-static int hostcache_inuse(void *data, void *hc)
+static int free_all_entries(void *data, void *hc)
{
- struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;
-
- if(c->inuse == 1)
- Curl_resolv_unlock(data, c);
-
+ (void)data;
+ (void)hc;
return 1; /* free all entries */
}
@@ -777,11 +762,13 @@ static int hostcache_inuse(void *data, void *hc)
void Curl_hostcache_clean(struct SessionHandle *data,
struct curl_hash *hash)
{
- /* Entries added to the hostcache with the CURLOPT_RESOLVE function are
- * still present in the cache with the inuse counter set to 1. Detect them
- * and cleanup!
- */
- Curl_hash_clean_with_criterium(hash, data, hostcache_inuse);
+ if(data && data->share)
+ Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
+
+ Curl_hash_clean_with_criterium(hash, NULL, free_all_entries);
+
+ if(data && data->share)
+ Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
}
@@ -830,9 +817,16 @@ CURLcode Curl_loadhostpairs(struct SessionHandle *data)
/* free the allocated entry_id again */
free(entry_id);
- if(!dns)
+ if(!dns) {
/* if not in the cache already, put this host in the cache */
dns = Curl_cache_addr(data, addr, hostname, port);
+ if(dns) {
+ dns->timestamp = 0; /* mark as added by CURLOPT_RESOLVE */
+ /* release the returned reference; the cache itself will keep the
+ * entry alive: */
+ dns->inuse--;
+ }
+ }
else
/* this is a duplicate, free it again */
Curl_freeaddrinfo(addr);
diff --git a/lib/hostip.h b/lib/hostip.h
index e1e880eab..0e2e2cf7f 100644
--- a/lib/hostip.h
+++ b/lib/hostip.h
@@ -65,11 +65,10 @@ void Curl_global_host_cache_dtor(void);
struct Curl_dns_entry {
Curl_addrinfo *addr;
- /* timestamp == 0 -- entry not in hostcache
- timestamp != 0 -- entry is in hostcache */
+ /* timestamp == 0 -- CURLOPT_RESOLVE entry, doesn't timeout */
time_t timestamp;
- long inuse; /* use-counter, make very sure you decrease this
- when you're done using the address you received */
+ /* use-counter, use Curl_resolv_unlock to release reference */
+ long inuse;
};
/*
diff --git a/tests/unit/unit1305.c b/tests/unit/unit1305.c
index 93815e5f8..4f9c609b0 100644
--- a/tests/unit/unit1305.c
+++ b/tests/unit/unit1305.c
@@ -128,6 +128,7 @@ UNITTEST_START
abort_unless(rc == CURLE_OK, "data node creation failed");
key_len = strlen(data_key);
+ data_node->inuse = 1; /* hash will hold the reference */
nodep = Curl_hash_add(hp, data_key, key_len+1, data_node);
abort_unless(nodep, "insertion into hash failed");
/* Freeing will now be done by Curl_hash_destroy */