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authorDaniel Stenberg <daniel@haxx.se>2017-12-02 14:27:00 +0100
committerDaniel Stenberg <daniel@haxx.se>2017-12-05 23:21:02 +0100
commit07cb27c98e92649e74a312faf976271fa7da609c (patch)
tree174c9985ca7e8623401117608e52b46afe2914c2 /lib
parent85f0133ea14f411b4dae9c6239c83a67ca7bca89 (diff)
conncache: fix several lock issues
If the lock is released before the dealings with the bundle is over, it may have changed by another thread in the mean time. Fixes #2132 Fixes #2151 Closes #2139
Diffstat (limited to 'lib')
-rw-r--r--lib/conncache.c222
-rw-r--r--lib/conncache.h26
-rw-r--r--lib/multi.c56
-rw-r--r--lib/url.c174
-rw-r--r--lib/urldata.h10
5 files changed, 306 insertions, 182 deletions
diff --git a/lib/conncache.c b/lib/conncache.c
index f8ef2e88b..43d885131 100644
--- a/lib/conncache.c
+++ b/lib/conncache.c
@@ -40,11 +40,26 @@
#include "curl_memory.h"
#include "memdebug.h"
+#ifdef CURLDEBUG
+/* the debug versions of these macros make extra certain that the lock is
+ never doubly locked or unlocked */
+#define CONN_LOCK(x) if((x)->share) { \
+ Curl_share_lock((x), CURL_LOCK_DATA_CONNECT, CURL_LOCK_ACCESS_SINGLE); \
+ DEBUGASSERT(!(x)->state.conncache_lock); \
+ (x)->state.conncache_lock = TRUE; \
+ }
+
+#define CONN_UNLOCK(x) if((x)->share) { \
+ DEBUGASSERT((x)->state.conncache_lock); \
+ (x)->state.conncache_lock = FALSE; \
+ Curl_share_unlock((x), CURL_LOCK_DATA_CONNECT); \
+ }
+#else
#define CONN_LOCK(x) if((x)->share) \
Curl_share_lock((x), CURL_LOCK_DATA_CONNECT, CURL_LOCK_ACCESS_SINGLE)
#define CONN_UNLOCK(x) if((x)->share) \
Curl_share_unlock((x), CURL_LOCK_DATA_CONNECT)
-
+#endif
static void conn_llist_dtor(void *user, void *element)
{
@@ -165,18 +180,48 @@ static void hashkey(struct connectdata *conn, char *buf,
snprintf(buf, len, "%ld%s", conn->port, hostname);
}
+void Curl_conncache_unlock(struct connectdata *conn)
+{
+ CONN_UNLOCK(conn->data);
+}
+
+/* Returns number of connections currently held in the connection cache.
+ Locks/unlocks the cache itself!
+*/
+size_t Curl_conncache_size(struct Curl_easy *data)
+{
+ size_t num;
+ CONN_LOCK(data);
+ num = data->state.conn_cache->num_conn;
+ CONN_UNLOCK(data);
+ return num;
+}
+
+/* Returns number of connections currently held in the connections's bundle
+ Locks/unlocks the cache itself!
+*/
+size_t Curl_conncache_bundle_size(struct connectdata *conn)
+{
+ size_t num;
+ CONN_LOCK(conn->data);
+ num = conn->bundle->num_connections;
+ CONN_UNLOCK(conn->data);
+ return num;
+}
+
/* Look up the bundle with all the connections to the same host this
- connectdata struct is setup to use. */
+ connectdata struct is setup to use.
+
+ **NOTE**: When it returns, it holds the connection cache lock! */
struct connectbundle *Curl_conncache_find_bundle(struct connectdata *conn,
struct conncache *connc)
{
struct connectbundle *bundle = NULL;
+ CONN_LOCK(conn->data);
if(connc) {
char key[128];
hashkey(conn, key, sizeof(key));
- CONN_LOCK(conn->data);
bundle = Curl_hash_pick(&connc->hash, key, strlen(key));
- CONN_UNLOCK(conn->data);
}
return bundle;
@@ -223,77 +268,89 @@ CURLcode Curl_conncache_add_conn(struct conncache *connc,
struct connectbundle *new_bundle = NULL;
struct Curl_easy *data = conn->data;
+ /* *find_bundle() locks the connection cache */
bundle = Curl_conncache_find_bundle(conn, data->state.conn_cache);
if(!bundle) {
int rc;
char key[128];
result = bundle_create(data, &new_bundle);
- if(result)
- return result;
+ if(result) {
+ goto unlock;
+ }
hashkey(conn, key, sizeof(key));
- CONN_LOCK(data);
rc = conncache_add_bundle(data->state.conn_cache, key, new_bundle);
- CONN_UNLOCK(data);
if(!rc) {
bundle_destroy(new_bundle);
- return CURLE_OUT_OF_MEMORY;
+ result = CURLE_OUT_OF_MEMORY;
+ goto unlock;
}
bundle = new_bundle;
}
- CONN_LOCK(data);
result = bundle_add_conn(bundle, conn);
if(result) {
if(new_bundle)
conncache_remove_bundle(data->state.conn_cache, new_bundle);
- CONN_UNLOCK(data);
- return result;
+ goto unlock;
}
- CONN_UNLOCK(data);
conn->connection_id = connc->next_connection_id++;
- connc->num_connections++;
+ connc->num_conn++;
DEBUGF(infof(conn->data, "Added connection %ld. "
"The cache now contains %" CURL_FORMAT_CURL_OFF_TU " members\n",
- conn->connection_id, (curl_off_t) connc->num_connections));
+ conn->connection_id, (curl_off_t) connc->num_conn));
+
+ unlock:
+ CONN_UNLOCK(data);
return CURLE_OK;
}
-void Curl_conncache_remove_conn(struct conncache *connc,
- struct connectdata *conn)
+void Curl_conncache_remove_conn(struct connectdata *conn, bool lock)
{
+ struct Curl_easy *data = conn->data;
struct connectbundle *bundle = conn->bundle;
+ struct conncache *connc = data->state.conn_cache;
/* The bundle pointer can be NULL, since this function can be called
due to a failed connection attempt, before being added to a bundle */
if(bundle) {
- CONN_LOCK(conn->data);
+ if(lock) {
+ CONN_LOCK(conn->data);
+ }
bundle_remove_conn(bundle, conn);
if(bundle->num_connections == 0)
conncache_remove_bundle(connc, bundle);
- CONN_UNLOCK(conn->data);
+ conn->bundle = NULL; /* removed from it */
if(connc) {
- connc->num_connections--;
-
+ connc->num_conn--;
DEBUGF(infof(conn->data, "The cache now contains %"
CURL_FORMAT_CURL_OFF_TU " members\n",
- (curl_off_t) connc->num_connections));
+ (curl_off_t) connc->num_conn));
+ }
+ if(lock) {
+ CONN_UNLOCK(conn->data);
}
}
}
-/* This function iterates the entire connection cache and calls the
- function func() with the connection pointer as the first argument
- and the supplied 'param' argument as the other,
+/* This function iterates the entire connection cache and calls the function
+ func() with the connection pointer as the first argument and the supplied
+ 'param' argument as the other.
+
+ The conncache lock is still held when the callback is called. It needs it,
+ so that it can safely continue traversing the lists once the callback
+ returns.
+
+ Returns 1 if the loop was aborted due to the callback's return code.
Return 0 from func() to continue the loop, return 1 to abort it.
*/
-void Curl_conncache_foreach(struct Curl_easy *data,
+bool Curl_conncache_foreach(struct Curl_easy *data,
struct conncache *connc,
void *param,
int (*func)(struct connectdata *conn, void *param))
@@ -303,7 +360,7 @@ void Curl_conncache_foreach(struct Curl_easy *data,
struct curl_hash_element *he;
if(!connc)
- return;
+ return FALSE;
CONN_LOCK(data);
Curl_hash_start_iterate(&connc->hash, &iter);
@@ -324,11 +381,12 @@ void Curl_conncache_foreach(struct Curl_easy *data,
if(1 == func(conn, param)) {
CONN_UNLOCK(data);
- return;
+ return TRUE;
}
}
}
CONN_UNLOCK(data);
+ return FALSE;
}
/* Return the first connection found in the cache. Used when closing all
@@ -363,16 +421,104 @@ Curl_conncache_find_first_connection(struct conncache *connc)
}
/*
- * This function finds the connection in the connection
- * cache that has been unused for the longest time.
+ * Give ownership of a connection back to the connection cache. Might
+ * disconnect the oldest existing in there to make space.
+ *
+ * Return TRUE if stored, FALSE if closed.
+ */
+bool Curl_conncache_return_conn(struct connectdata *conn)
+{
+ struct Curl_easy *data = conn->data;
+
+ /* data->multi->maxconnects can be negative, deal with it. */
+ size_t maxconnects =
+ (data->multi->maxconnects < 0) ? data->multi->num_easy * 4:
+ data->multi->maxconnects;
+ struct connectdata *conn_candidate = NULL;
+
+ if(maxconnects > 0 &&
+ Curl_conncache_size(data) > maxconnects) {
+ infof(data, "Connection cache is full, closing the oldest one.\n");
+
+ conn_candidate = Curl_conncache_extract_oldest(data);
+
+ if(conn_candidate) {
+ /* Set the connection's owner correctly */
+ conn_candidate->data = data;
+
+ /* the winner gets the honour of being disconnected */
+ (void)Curl_disconnect(conn_candidate, /* dead_connection */ FALSE);
+ }
+ }
+ CONN_LOCK(data);
+ conn->inuse = FALSE; /* Mark the connection unused */
+ CONN_UNLOCK(data);
+
+ return (conn_candidate == conn) ? FALSE : TRUE;
+
+}
+
+/*
+ * This function finds the connection in the connection bundle that has been
+ * unused for the longest time.
+ *
+ * Does not lock the connection cache!
*
* Returns the pointer to the oldest idle connection, or NULL if none was
* found.
*/
struct connectdata *
-Curl_conncache_oldest_idle(struct Curl_easy *data)
+Curl_conncache_extract_bundle(struct Curl_easy *data,
+ struct connectbundle *bundle)
+{
+ struct curl_llist_element *curr;
+ timediff_t highscore = -1;
+ timediff_t score;
+ struct curltime now;
+ struct connectdata *conn_candidate = NULL;
+ struct connectdata *conn;
+
+ (void)data;
+
+ now = Curl_now();
+
+ curr = bundle->conn_list.head;
+ while(curr) {
+ conn = curr->ptr;
+
+ if(!conn->inuse) {
+ /* Set higher score for the age passed since the connection was used */
+ score = Curl_timediff(now, conn->now);
+
+ if(score > highscore) {
+ highscore = score;
+ conn_candidate = conn;
+ }
+ }
+ curr = curr->next;
+ }
+ if(conn_candidate) {
+ /* remove it to prevent another thread from nicking it */
+ bundle_remove_conn(bundle, conn_candidate);
+ data->state.conn_cache->num_conn--;
+ DEBUGF(infof(data, "The cache now contains %"
+ CURL_FORMAT_CURL_OFF_TU " members\n",
+ (curl_off_t) data->state.conn_cache->num_conn));
+ }
+
+ return conn_candidate;
+}
+
+/*
+ * This function finds the connection in the connection cache that has been
+ * unused for the longest time and extracts that from the bundle.
+ *
+ * Returns the pointer to the connection, or NULL if none was found.
+ */
+struct connectdata *
+Curl_conncache_extract_oldest(struct Curl_easy *data)
{
- struct conncache *bc = data->state.conn_cache;
+ struct conncache *connc = data->state.conn_cache;
struct curl_hash_iterator iter;
struct curl_llist_element *curr;
struct curl_hash_element *he;
@@ -381,11 +527,12 @@ Curl_conncache_oldest_idle(struct Curl_easy *data)
struct curltime now;
struct connectdata *conn_candidate = NULL;
struct connectbundle *bundle;
+ struct connectbundle *bundle_candidate = NULL;
now = Curl_now();
CONN_LOCK(data);
- Curl_hash_start_iterate(&bc->hash, &iter);
+ Curl_hash_start_iterate(&connc->hash, &iter);
he = Curl_hash_next_element(&iter);
while(he) {
@@ -404,6 +551,7 @@ Curl_conncache_oldest_idle(struct Curl_easy *data)
if(score > highscore) {
highscore = score;
conn_candidate = conn;
+ bundle_candidate = bundle;
}
}
curr = curr->next;
@@ -411,6 +559,14 @@ Curl_conncache_oldest_idle(struct Curl_easy *data)
he = Curl_hash_next_element(&iter);
}
+ if(conn_candidate) {
+ /* remove it to prevent another thread from nicking it */
+ bundle_remove_conn(bundle_candidate, conn_candidate);
+ connc->num_conn--;
+ DEBUGF(infof(data, "The cache now contains %"
+ CURL_FORMAT_CURL_OFF_TU " members\n",
+ (curl_off_t) connc->num_conn));
+ }
CONN_UNLOCK(data);
return conn_candidate;
diff --git a/lib/conncache.h b/lib/conncache.h
index 0d97a6cef..d8ad80f96 100644
--- a/lib/conncache.h
+++ b/lib/conncache.h
@@ -23,9 +23,15 @@
*
***************************************************************************/
+/*
+ * All accesses to struct fields and changing of data in the connection cache
+ * and connectbundles must be done with the conncache LOCKED. The cache might
+ * be shared.
+ */
+
struct conncache {
struct curl_hash hash;
- size_t num_connections;
+ size_t num_conn;
long next_connection_id;
struct curltime last_cleanup;
/* handle used for closing cached connections */
@@ -50,14 +56,17 @@ void Curl_conncache_destroy(struct conncache *connc);
/* return the correct bundle, to a host or a proxy */
struct connectbundle *Curl_conncache_find_bundle(struct connectdata *conn,
struct conncache *connc);
+void Curl_conncache_unlock(struct connectdata *conn);
+/* returns number of connections currently held in the connection cache */
+size_t Curl_conncache_size(struct Curl_easy *data);
+size_t Curl_conncache_bundle_size(struct connectdata *conn);
+bool Curl_conncache_return_conn(struct connectdata *conn);
CURLcode Curl_conncache_add_conn(struct conncache *connc,
struct connectdata *conn);
-
-void Curl_conncache_remove_conn(struct conncache *connc,
- struct connectdata *conn);
-
-void Curl_conncache_foreach(struct Curl_easy *data,
+void Curl_conncache_remove_conn(struct connectdata *conn,
+ bool lock);
+bool Curl_conncache_foreach(struct Curl_easy *data,
struct conncache *connc,
void *param,
int (*func)(struct connectdata *conn,
@@ -67,7 +76,10 @@ struct connectdata *
Curl_conncache_find_first_connection(struct conncache *connc);
struct connectdata *
-Curl_conncache_oldest_idle(struct Curl_easy *data);
+Curl_conncache_extract_bundle(struct Curl_easy *data,
+ struct connectbundle *bundle);
+struct connectdata *
+Curl_conncache_extract_oldest(struct Curl_easy *data);
void Curl_conncache_close_all_connections(struct conncache *connc);
void Curl_conncache_print(struct conncache *connc);
diff --git a/lib/multi.c b/lib/multi.c
index 9728e5a2f..1a4618eb2 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -479,38 +479,6 @@ static void debug_print_sock_hash(void *p)
}
#endif
-/* Mark the connection as 'idle', or close it if the cache is full.
- Returns TRUE if the connection is kept, or FALSE if it was closed. */
-static bool
-ConnectionDone(struct Curl_easy *data, struct connectdata *conn)
-{
- /* data->multi->maxconnects can be negative, deal with it. */
- size_t maxconnects =
- (data->multi->maxconnects < 0) ? data->multi->num_easy * 4:
- data->multi->maxconnects;
- struct connectdata *conn_candidate = NULL;
-
- /* Mark the current connection as 'unused' */
- conn->inuse = FALSE;
-
- if(maxconnects > 0 &&
- data->state.conn_cache->num_connections > maxconnects) {
- infof(data, "Connection cache is full, closing the oldest one.\n");
-
- conn_candidate = Curl_conncache_oldest_idle(data);
-
- if(conn_candidate) {
- /* Set the connection's owner correctly */
- conn_candidate->data = data;
-
- /* the winner gets the honour of being disconnected */
- (void)Curl_disconnect(conn_candidate, /* dead_connection */ FALSE);
- }
- }
-
- return (conn_candidate == conn) ? FALSE : TRUE;
-}
-
static CURLcode multi_done(struct connectdata **connp,
CURLcode status, /* an error if this is called
after an error was detected */
@@ -621,17 +589,21 @@ static CURLcode multi_done(struct connectdata **connp,
result = res2;
}
else {
+ char buffer[256];
+ /* create string before returning the connection */
+ snprintf(buffer, sizeof(buffer),
+ "Connection #%ld to host %s left intact",
+ conn->connection_id,
+ conn->bits.socksproxy ? conn->socks_proxy.host.dispname :
+ conn->bits.httpproxy ? conn->http_proxy.host.dispname :
+ conn->bits.conn_to_host ? conn->conn_to_host.dispname :
+ conn->host.dispname);
+
/* the connection is no longer in use */
- if(ConnectionDone(data, conn)) {
+ if(Curl_conncache_return_conn(conn)) {
/* remember the most recently used connection */
data->state.lastconnect = conn;
-
- infof(data, "Connection #%ld to host %s left intact\n",
- conn->connection_id,
- conn->bits.socksproxy ? conn->socks_proxy.host.dispname :
- conn->bits.httpproxy ? conn->http_proxy.host.dispname :
- conn->bits.conn_to_host ? conn->conn_to_host.dispname :
- conn->host.dispname);
+ infof(data, "%s\n", buffer);
}
else
data->state.lastconnect = NULL;
@@ -1357,16 +1329,16 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
}
if(data->easy_conn && data->mstate > CURLM_STATE_CONNECT &&
- data->mstate < CURLM_STATE_COMPLETED)
+ data->mstate < CURLM_STATE_COMPLETED) {
/* Make sure we set the connection's current owner */
data->easy_conn->data = data;
+ }
if(data->easy_conn &&
(data->mstate >= CURLM_STATE_CONNECT) &&
(data->mstate < CURLM_STATE_COMPLETED)) {
/* we need to wait for the connect state as only then is the start time
stored, but we must not check already completed handles */
-
timeout_ms = Curl_timeleft(data, &now,
(data->mstate <= CURLM_STATE_WAITDO)?
TRUE:FALSE);
diff --git a/lib/url.c b/lib/url.c
index 731e67e17..b38e88eec 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -127,10 +127,6 @@ bool curl_win32_idn_to_ascii(const char *in, char **out);
#include "curl_memory.h"
#include "memdebug.h"
-/* Local static prototypes */
-static struct connectdata *
-find_oldest_idle_connection_in_bundle(struct Curl_easy *data,
- struct connectbundle *bundle);
static void conn_free(struct connectdata *conn);
static void free_fixed_hostname(struct hostname *host);
static void signalPipeClose(struct curl_llist *pipeline, bool pipe_broke);
@@ -722,7 +718,6 @@ static void conn_free(struct connectdata *conn)
#ifdef USE_SSL
Curl_safefree(conn->ssl_extra);
#endif
-
free(conn); /* free all the connection oriented data */
}
@@ -777,7 +772,7 @@ CURLcode Curl_disconnect(struct connectdata *conn, bool dead_connection)
/* unlink ourselves! */
infof(data, "Closing connection %ld\n", conn->connection_id);
- Curl_conncache_remove_conn(data->state.conn_cache, conn);
+ Curl_conncache_remove_conn(conn, TRUE);
free_fixed_hostname(&conn->host);
free_fixed_hostname(&conn->conn_to_host);
@@ -943,56 +938,17 @@ proxy_info_matches(const struct proxy_info* data,
return FALSE;
}
-
/*
- * This function finds the connection in the connection
- * bundle that has been unused for the longest time.
+ * This function checks if the given connection is dead and extracts it from
+ * the connection cache if so.
*
- * Returns the pointer to the oldest idle connection, or NULL if none was
- * found.
- */
-static struct connectdata *
-find_oldest_idle_connection_in_bundle(struct Curl_easy *data,
- struct connectbundle *bundle)
-{
- struct curl_llist_element *curr;
- timediff_t highscore = -1;
- timediff_t score;
- struct curltime now;
- struct connectdata *conn_candidate = NULL;
- struct connectdata *conn;
-
- (void)data;
-
- now = Curl_now();
-
- curr = bundle->conn_list.head;
- while(curr) {
- conn = curr->ptr;
-
- if(!conn->inuse) {
- /* Set higher score for the age passed since the connection was used */
- score = Curl_timediff(now, conn->now);
-
- if(score > highscore) {
- highscore = score;
- conn_candidate = conn;
- }
- }
- curr = curr->next;
- }
-
- return conn_candidate;
-}
-
-/*
- * This function checks if given connection is dead and disconnects if so.
- * (That also removes it from the connection cache.)
+ * When this is called as a Curl_conncache_foreach() callback, the connection
+ * cache lock is held!
*
- * Returns TRUE if the connection actually was dead and disconnected.
+ * Returns TRUE if the connection was dead and extracted.
*/
-static bool disconnect_if_dead(struct connectdata *conn,
- struct Curl_easy *data)
+static bool extract_if_dead(struct connectdata *conn,
+ struct Curl_easy *data)
{
size_t pipeLen = conn->send_pipe.size + conn->recv_pipe.size;
if(!pipeLen && !conn->inuse) {
@@ -1017,25 +973,30 @@ static bool disconnect_if_dead(struct connectdata *conn,
if(dead) {
conn->data = data;
infof(data, "Connection %ld seems to be dead!\n", conn->connection_id);
-
- /* disconnect resources */
- Curl_disconnect(conn, /* dead_connection */TRUE);
+ Curl_conncache_remove_conn(conn, FALSE);
return TRUE;
}
}
return FALSE;
}
+struct prunedead {
+ struct Curl_easy *data;
+ struct connectdata *extracted;
+};
+
/*
- * Wrapper to use disconnect_if_dead() function in Curl_conncache_foreach()
+ * Wrapper to use extract_if_dead() function in Curl_conncache_foreach()
*
- * Returns always 0.
*/
-static int call_disconnect_if_dead(struct connectdata *conn,
- void *param)
+static int call_extract_if_dead(struct connectdata *conn, void *param)
{
- struct Curl_easy* data = (struct Curl_easy*)param;
- disconnect_if_dead(conn, data);
+ struct prunedead *p = (struct prunedead *)param;
+ if(extract_if_dead(conn, p->data)) {
+ /* stop the iteration here, pass back the connection that was extracted */
+ p->extracted = conn;
+ return 1;
+ }
return 0; /* continue iteration */
}
@@ -1050,8 +1011,14 @@ static void prune_dead_connections(struct Curl_easy *data)
time_t elapsed = Curl_timediff(now, data->state.conn_cache->last_cleanup);
if(elapsed >= 1000L) {
- Curl_conncache_foreach(data, data->state.conn_cache, data,
- call_disconnect_if_dead);
+ struct prunedead prune;
+ prune.data = data;
+ prune.extracted = NULL;
+ while(Curl_conncache_foreach(data, data->state.conn_cache, &prune,
+ call_extract_if_dead)) {
+ /* disconnect it */
+ (void)Curl_disconnect(prune.extracted, /* dead_connection */TRUE);
+ }
data->state.conn_cache->last_cleanup = now;
}
}
@@ -1106,8 +1073,8 @@ ConnectionExists(struct Curl_easy *data,
Curl_pipeline_site_blacklisted(data, needle))
canpipe &= ~ CURLPIPE_HTTP1;
- /* Look up the bundle with all the connections to this
- particular host */
+ /* Look up the bundle with all the connections to this particular host.
+ Locks the connection cache, beware of early returns! */
bundle = Curl_conncache_find_bundle(needle, data->state.conn_cache);
if(bundle) {
/* Max pipe length is zero (unlimited) for multiplexed connections */
@@ -1130,6 +1097,7 @@ ConnectionExists(struct Curl_easy *data,
if((bundle->multiuse == BUNDLE_UNKNOWN) && data->set.pipewait) {
infof(data, "Server doesn't support multi-use yet, wait\n");
*waitpipe = TRUE;
+ Curl_conncache_unlock(needle);
return FALSE; /* no re-use */
}
@@ -1161,8 +1129,11 @@ ConnectionExists(struct Curl_easy *data,
check = curr->ptr;
curr = curr->next;
- if(disconnect_if_dead(check, data))
+ if(extract_if_dead(check, data)) {
+ /* disconnect it */
+ (void)Curl_disconnect(check, /* dead_connection */TRUE);
continue;
+ }
pipeLen = check->send_pipe.size + check->recv_pipe.size;
@@ -1479,9 +1450,13 @@ ConnectionExists(struct Curl_easy *data,
}
if(chosen) {
+ /* mark it as used before releasing the lock */
+ chosen->inuse = TRUE;
+ Curl_conncache_unlock(needle);
*usethis = chosen;
return TRUE; /* yes, we found one to use! */
}
+ Curl_conncache_unlock(needle);
if(foundPendingCandidate && data->set.pipewait) {
infof(data,
@@ -4409,20 +4384,21 @@ static CURLcode create_conn(struct Curl_easy *data,
else
reuse = ConnectionExists(data, conn, &conn_temp, &force_reuse, &waitpipe);
- /* If we found a reusable connection, we may still want to
- open a new connection if we are pipelining. */
+ /* If we found a reusable connection that is now marked as in use, we may
+ still want to open a new connection if we are pipelining. */
if(reuse && !force_reuse && IsPipeliningPossible(data, conn_temp)) {
size_t pipelen = conn_temp->send_pipe.size + conn_temp->recv_pipe.size;
if(pipelen > 0) {
infof(data, "Found connection %ld, with requests in the pipe (%zu)\n",
conn_temp->connection_id, pipelen);
- if(conn_temp->bundle->num_connections < max_host_connections &&
- data->state.conn_cache->num_connections < max_total_connections) {
+ if(Curl_conncache_bundle_size(conn_temp) < max_host_connections &&
+ Curl_conncache_size(data) < max_total_connections) {
/* We want a new connection anyway */
reuse = FALSE;
infof(data, "We can reuse, but we want a new connection anyway\n");
+ Curl_conncache_return_conn(conn_temp);
}
}
}
@@ -4434,8 +4410,6 @@ static CURLcode create_conn(struct Curl_easy *data,
* just allocated before we can move along and use the previously
* existing one.
*/
- conn_temp->inuse = TRUE; /* mark this as being in use so that no other
- handle in a multi stack may nick it */
reuse_conn(conn, conn_temp);
#ifdef USE_SSL
free(conn->ssl_extra);
@@ -4455,7 +4429,6 @@ static CURLcode create_conn(struct Curl_easy *data,
/* We have decided that we want a new connection. However, we may not
be able to do that if we have reached the limit of how many
connections we are allowed to open. */
- struct connectbundle *bundle = NULL;
if(conn->handler->flags & PROTOPT_ALPN_NPN) {
/* The protocol wants it, so set the bits if enabled in the easy handle
@@ -4470,35 +4443,42 @@ static CURLcode create_conn(struct Curl_easy *data,
/* There is a connection that *might* become usable for pipelining
"soon", and we wait for that */
connections_available = FALSE;
- else
- bundle = Curl_conncache_find_bundle(conn, data->state.conn_cache);
-
- if(max_host_connections > 0 && bundle &&
- (bundle->num_connections >= max_host_connections)) {
- struct connectdata *conn_candidate;
-
- /* The bundle is full. Let's see if we can kill a connection. */
- conn_candidate = find_oldest_idle_connection_in_bundle(data, bundle);
-
- if(conn_candidate) {
- /* Set the connection's owner correctly, then kill it */
- conn_candidate->data = data;
- (void)Curl_disconnect(conn_candidate, /* dead_connection */ FALSE);
- }
- else {
- infof(data, "No more connections allowed to host: %d\n",
- max_host_connections);
- connections_available = FALSE;
+ else {
+ /* this gets a lock on the conncache */
+ struct connectbundle *bundle =
+ Curl_conncache_find_bundle(conn, data->state.conn_cache);
+
+ if(max_host_connections > 0 && bundle &&
+ (bundle->num_connections >= max_host_connections)) {
+ struct connectdata *conn_candidate;
+
+ /* The bundle is full. Extract the oldest connection. */
+ conn_candidate = Curl_conncache_extract_bundle(data, bundle);
+ Curl_conncache_unlock(conn);
+
+ if(conn_candidate) {
+ /* Set the connection's owner correctly, then kill it */
+ conn_candidate->data = data;
+ (void)Curl_disconnect(conn_candidate, /* dead_connection */ FALSE);
+ }
+ else {
+ infof(data, "No more connections allowed to host: %d\n",
+ max_host_connections);
+ connections_available = FALSE;
+ }
}
+ else
+ Curl_conncache_unlock(conn);
+
}
if(connections_available &&
(max_total_connections > 0) &&
- (data->state.conn_cache->num_connections >= max_total_connections)) {
+ (Curl_conncache_size(data) >= max_total_connections)) {
struct connectdata *conn_candidate;
/* The cache is full. Let's see if we can kill a connection. */
- conn_candidate = Curl_conncache_oldest_idle(data);
+ conn_candidate = Curl_conncache_extract_oldest(data);
if(conn_candidate) {
/* Set the connection's owner correctly, then kill it */
@@ -4521,6 +4501,9 @@ static CURLcode create_conn(struct Curl_easy *data,
goto out;
}
else {
+ /* Mark the connection as used, before we add it */
+ conn->inuse = TRUE;
+
/*
* This is a brand new connection, so let's store it in the connection
* cache of ours!
@@ -4548,9 +4531,6 @@ static CURLcode create_conn(struct Curl_easy *data,
#endif
}
- /* Mark the connection as used */
- conn->inuse = TRUE;
-
/* Setup and init stuff before DO starts, in preparing for the transfer. */
Curl_init_do(data, conn);
diff --git a/lib/urldata.h b/lib/urldata.h
index ed6bbb4f0..19cb6cafd 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -775,9 +775,10 @@ struct connectdata {
void *closesocket_client;
bool inuse; /* This is a marker for the connection cache logic. If this is
- TRUE this handle is being used by an easy handle and cannot
- be used by any other easy handle without careful
- consideration (== only for pipelining). */
+ TRUE this handle is being used by one or more easy handles
+ and can only used by any other easy handle without careful
+ consideration (== only for pipelining/multiplexing) and it
+ cannot be used by another multi handle! */
/**** Fields set when inited and not modified again */
long connection_id; /* Contains a unique number to make it easier to
@@ -1325,6 +1326,9 @@ struct UrlState {
struct Curl_easy *stream_depends_on;
bool stream_depends_e; /* set or don't set the Exclusive bit */
int stream_weight;
+#ifdef CURLDEBUG
+ bool conncache_lock;
+#endif
};