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Cygwin: FIFO: lock fixes

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Add some missing locks and remove one extra unlock.  Clarify for some
functions whether caller or callee acquires lock, and add appropriate
comments.
This commit is contained in:
Ken Brown 2020-07-31 13:55:17 -04:00
parent cb7fba2f3e
commit e319fd0e62
1 changed files with 17 additions and 6 deletions
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23
winsup/cygwin/fhandler_fifo.cc
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@ -316,6 +316,7 @@ fhandler_fifo::wait_open_pipe (HANDLE& ph)
return status; return status;
} }
/* Always called with fifo_client_lock in place. */
int int
fhandler_fifo::add_client_handler (bool new_pipe_instance) fhandler_fifo::add_client_handler (bool new_pipe_instance)
{ {
@ -345,6 +346,7 @@ fhandler_fifo::add_client_handler (bool new_pipe_instance)
return 0; return 0;
} }
/* Always called with fifo_client_lock in place. */
void void
fhandler_fifo::delete_client_handler (int i) fhandler_fifo::delete_client_handler (int i)
{ {
@ -354,7 +356,8 @@ fhandler_fifo::delete_client_handler (int i)
(nhandlers - i) * sizeof (fc_handler[i])); (nhandlers - i) * sizeof (fc_handler[i]));
} }
/* Delete handlers that we will never read from. */ /* Delete handlers that we will never read from. Always called with
fifo_client_lock in place. */
void void
fhandler_fifo::cleanup_handlers () fhandler_fifo::cleanup_handlers ()
{ {
@ -369,6 +372,7 @@ fhandler_fifo::cleanup_handlers ()
} }
} }
/* Always called with fifo_client_lock in place. */
void void
fhandler_fifo::record_connection (fifo_client_handler& fc, fhandler_fifo::record_connection (fifo_client_handler& fc,
fifo_client_connect_state s) fifo_client_connect_state s)
@ -398,6 +402,7 @@ fhandler_fifo::update_my_handlers ()
if (!prev_proc) if (!prev_proc)
api_fatal ("Can't open process of previous owner, %E"); api_fatal ("Can't open process of previous owner, %E");
fifo_client_lock ();
for (int i = 0; i < get_shared_nhandlers (); i++) for (int i = 0; i < get_shared_nhandlers (); i++)
{ {
if (add_client_handler (false) < 0) if (add_client_handler (false) < 0)
@ -419,10 +424,12 @@ fhandler_fifo::update_my_handlers ()
fc.last_read = shared_fc_handler[i].last_read; fc.last_read = shared_fc_handler[i].last_read;
} }
} }
fifo_client_unlock ();
set_prev_owner (null_fr_id); set_prev_owner (null_fr_id);
return ret; return ret;
} }
/* Always called with fifo_client_lock and owner_lock in place. */
int int
fhandler_fifo::update_shared_handlers () fhandler_fifo::update_shared_handlers ()
{ {
@ -435,9 +442,7 @@ fhandler_fifo::update_shared_handlers ()
set_shared_nhandlers (nhandlers); set_shared_nhandlers (nhandlers);
memcpy (shared_fc_handler, fc_handler, nhandlers * sizeof (fc_handler[0])); memcpy (shared_fc_handler, fc_handler, nhandlers * sizeof (fc_handler[0]));
shared_fc_handler_updated (true); shared_fc_handler_updated (true);
owner_lock ();
set_prev_owner (me); set_prev_owner (me);
owner_unlock ();
return 0; return 0;
} }
@ -509,7 +514,6 @@ fhandler_fifo::fifo_reader_thread_func ()
if (update_my_handlers () < 0) if (update_my_handlers () < 0)
debug_printf ("error updating my handlers, %E"); debug_printf ("error updating my handlers, %E");
owner_found (); owner_found ();
owner_unlock ();
/* Fall through to owner_listen. */ /* Fall through to owner_listen. */
} }
} }
@ -602,8 +606,13 @@ owner_listen:
} }
if (ph) if (ph)
NtClose (ph); NtClose (ph);
if (update && update_shared_handlers () < 0) if (update)
api_fatal ("Can't update shared handlers, %E"); {
owner_lock ();
if (get_owner () == me && update_shared_handlers () < 0)
api_fatal ("Can't update shared handlers, %E");
owner_unlock ();
}
fifo_client_unlock (); fifo_client_unlock ();
if (cancel) if (cancel)
goto canceled; goto canceled;
@ -1402,9 +1411,11 @@ fhandler_fifo::fstatvfs (struct statvfs *sfs)
void void
fhandler_fifo::close_all_handlers () fhandler_fifo::close_all_handlers ()
{ {
fifo_client_lock ();
for (int i = 0; i < nhandlers; i++) for (int i = 0; i < nhandlers; i++)
fc_handler[i].close (); fc_handler[i].close ();
nhandlers = 0; nhandlers = 0;
fifo_client_unlock ();
} }
fifo_client_connect_state fifo_client_connect_state