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Cygwin: FIFO: dup/fork/exec: make sure child starts unlocked

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There can be deadlocks if the child starts with its fifo_client_lock
in the locked state.
This commit is contained in:
Ken Brown 2020-05-04 11:36:20 -04:00
parent 624fda1e96
commit 13c65c43c2
1 changed files with 23 additions and 8 deletions
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31
winsup/cygwin/fhandler_fifo.cc
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@ -981,6 +981,9 @@ fhandler_fifo::dup (fhandler_base *child, int flags)
}
if (reader)
{
/* Make sure the child starts unlocked. */
fhf->fifo_client_unlock ();
fifo_client_lock ();
for (i = 0; i < nhandlers; i++)
{
@ -1025,20 +1028,32 @@ fhandler_fifo::fixup_after_fork (HANDLE parent)
fhandler_base::fixup_after_fork (parent);
fork_fixup (parent, read_ready, "read_ready");
fork_fixup (parent, write_ready, "write_ready");
fifo_client_lock ();
for (int i = 0; i < nhandlers; i++)
fork_fixup (parent, fc_handler[i].h, "fc_handler[].h");
fifo_client_unlock ();
if (reader && !listen_client ())
debug_printf ("failed to start lct, %E");
if (reader)
{
/* Make sure the child starts unlocked. */
fifo_client_unlock ();
fifo_client_lock ();
for (int i = 0; i < nhandlers; i++)
fork_fixup (parent, fc_handler[i].h, "fc_handler[].h");
fifo_client_unlock ();
if (!listen_client ())
debug_printf ("failed to start lct, %E");
}
}
void
fhandler_fifo::fixup_after_exec ()
{
fhandler_base::fixup_after_exec ();
if (reader && !listen_client ())
debug_printf ("failed to start lct, %E");
if (reader && !close_on_exec ())
{
/* Make sure the child starts unlocked. */
fifo_client_unlock ();
if (!listen_client ())
debug_printf ("failed to start lct, %E");
}
}
void