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multi: track users of a socket better

They need to be removed from the socket hash linked list with more care.

When sh_delentry() is called to remove a sockethash entry, remove all
individual transfers from the list first. To enable this, each Curl_easy struct
now stores a pointer to the sockethash entry to know how to remove itself.

Reported-by: Tom van der Woerdt and Kunal Ekawde

Fixes #3952
Fixes #3904
Closes #3953
This commit is contained in:
Daniel Stenberg 2019-05-28 08:23:43 +02:00
parent 28526e9c80
commit 8581e1928e
No known key found for this signature in database
GPG Key ID: 5CC908FDB71E12C2
2 changed files with 27 additions and 12 deletions

View File

@ -241,8 +241,17 @@ static struct Curl_sh_entry *sh_addentry(struct curl_hash *sh,
/* delete the given socket + handle from the hash */
static void sh_delentry(struct curl_hash *sh, curl_socket_t s)
static void sh_delentry(struct Curl_sh_entry *entry,
struct curl_hash *sh, curl_socket_t s)
{
struct curl_llist *list = &entry->list;
struct curl_llist_element *e;
/* clear the list of transfers first */
for(e = list->head; e; e = list->head) {
struct Curl_easy *dta = e->ptr;
Curl_llist_remove(&entry->list, e, NULL);
dta->sh_entry = NULL;
}
/* We remove the hash entry. This will end up in a call to
sh_freeentry(). */
Curl_hash_delete(sh, (char *)&s, sizeof(curl_socket_t));
@ -780,6 +789,11 @@ bool Curl_multiplex_wanted(const struct Curl_multi *multi)
static void detach_connnection(struct Curl_easy *data)
{
struct connectdata *conn = data->conn;
if(data->sh_entry) {
/* still listed as a user of a socket hash entry, remove it */
Curl_llist_remove(&data->sh_entry->list, &data->sh_queue, NULL);
data->sh_entry = NULL;
}
if(conn)
Curl_llist_remove(&conn->easyq, &data->conn_queue, NULL);
data->conn = NULL;
@ -2276,6 +2290,7 @@ static CURLMcode singlesocket(struct Curl_multi *multi,
/* add 'data' to the list of handles using this socket! */
Curl_llist_insert_next(&entry->list, entry->list.tail,
data, &data->sh_queue);
data->sh_entry = entry;
}
comboaction = (entry->writers? CURL_POLL_OUT : 0) |
@ -2335,11 +2350,7 @@ static CURLMcode singlesocket(struct Curl_multi *multi,
multi->socket_cb(data, s, CURL_POLL_REMOVE,
multi->socket_userp,
entry->socketp);
sh_delentry(&multi->sockhash, s);
}
else {
/* remove this transfer as a user of this socket */
Curl_llist_remove(&entry->list, &data->sh_queue, NULL);
sh_delentry(entry, &multi->sockhash, s);
}
}
} /* for loop over numsocks */
@ -2383,7 +2394,7 @@ void Curl_multi_closed(struct Curl_easy *data, curl_socket_t s)
entry->socketp);
/* now remove it from the socket hash */
sh_delentry(&multi->sockhash, s);
sh_delentry(entry, &multi->sockhash, s);
}
}
}
@ -2474,7 +2485,6 @@ static CURLMcode multi_socket(struct Curl_multi *multi,
return result;
}
if(s != CURL_SOCKET_TIMEOUT) {
struct Curl_sh_entry *entry = sh_getentry(&multi->sockhash, s);
if(!entry)
@ -2487,15 +2497,19 @@ static CURLMcode multi_socket(struct Curl_multi *multi,
else {
struct curl_llist *list = &entry->list;
struct curl_llist_element *e;
struct curl_llist_element *enext;
SIGPIPE_VARIABLE(pipe_st);
/* the socket can be shared by many transfers, iterate */
for(e = list->head; e; e = e->next) {
for(e = list->head; e; e = enext) {
data = (struct Curl_easy *)e->ptr;
if(data->magic != CURLEASY_MAGIC_NUMBER)
/* bad bad bad bad bad bad bad */
return CURLM_INTERNAL_ERROR;
/* assign 'enext' here since the 'e' struct might be cleared
further down in the singlesocket() call */
enext = e->next;
DEBUGASSERT(data);
DEBUGASSERT(data->magic == CURLEASY_MAGIC_NUMBER);
if(data->conn && !(data->conn->handler->flags & PROTOPT_DIRLOCK))
/* set socket event bitmask if they're not locked */

View File

@ -1778,6 +1778,7 @@ struct Curl_easy {
struct connectdata *conn;
struct curl_llist_element connect_queue;
struct curl_llist_element sh_queue; /* list per Curl_sh_entry */
struct Curl_sh_entry *sh_entry; /* the socket hash this was added to */
struct curl_llist_element conn_queue; /* list per connectdata */
CURLMstate mstate; /* the handle's state */