Unverified Commit 8581e192 authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

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
parent 28526e9c

lib/multi.c

+26 −12
Original line number Diff line number Diff line
@@ -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 */

lib/urldata.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */