multi: make sure 'data' can present in several sockhash entries

Since more than one socket can be used by each transfer at a given time,
each sockhash entry how has its own hash table with transfers using that
socket.

In addition, the sockhash entry can now be marked 'blocked = TRUE'"
which then makes the delete function just set 'removed = TRUE' instead
of removing it "for real", as a way to not rip out the carpet under the
feet of a parent function that iterates over the transfers of that same
sockhash entry.

Reported-by: Tom van der Woerdt
Fixes #3961
Fixes #3986
Fixes #3995
Fixes #4004
Closes #3997

1 files changed, 1 insertions, 8 deletions

diff --git a/lib/url.c b/lib/url.c
index eb22dcc37..c37ce0494 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -1673,13 +1673,6 @@ static void free_idnconverted_hostname(struct hostname *host)
 #endif
 }
 
-static void llist_dtor(void *user, void *element)
-{
-  (void)user;
-  (void)element;
-  /* Do nothing */
-}
-
 /*
  * Allocate and initialize a new connectdata object.
  */
@@ -1791,7 +1784,7 @@ static struct connectdata *allocate_conn(struct Curl_easy *data)
 #endif
 
   /* Initialize the easy handle list */
-  Curl_llist_init(&conn->easyq, (curl_llist_dtor) llist_dtor);
+  Curl_llist_init(&conn->easyq, NULL);
 
 #ifdef HAVE_GSSAPI
   conn->data_prot = PROT_CLEAR;