diff options
Diffstat (limited to 'winsup/cygwin/select.cc')
| -rw-r--r-- | winsup/cygwin/select.cc | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/winsup/cygwin/select.cc b/winsup/cygwin/select.cc index 1ba3ef3d8..78d1aaabe 100644 --- a/winsup/cygwin/select.cc +++ b/winsup/cygwin/select.cc @@ -389,7 +389,7 @@ peek_pipe (select_record *s, int ignra) fhandler_base *fh = s->fh; HANDLE h; - HANDLE guard_mutex = s->fh->get_guard (); + HANDLE guard_mutex = fh->get_guard (); set_handle_or_return_if_not_open (h, s); /* Don't perform complicated tests if we don't need to. */ @@ -438,12 +438,23 @@ peek_pipe (select_record *s, int ignra) select_printf ("%s, PeekNamedPipe failed, %E", fh->get_name ()); n = -1; } - else if (n && guard_mutex - && WaitForSingleObject (guard_mutex, 0) != WAIT_OBJECT_0) + else if (n && guard_mutex) { - select_printf ("%s, couldn't get mutex %p, %E", fh->get_name (), - guard_mutex); - n = 0; + if (WaitForSingleObject (guard_mutex, 0) != WAIT_OBJECT_0) + { + select_printf ("%s, couldn't get mutex %p, %E", fh->get_name (), + guard_mutex); + n = 0; + } + /* Now that we have the mutex, make sure that no one else has snuck + in and grabbed the data that we originally saw. */ + if (!PeekNamedPipe (h, NULL, 0, NULL, (DWORD *) &n, NULL)) + { + select_printf ("%s, PeekNamedPipe failed, %E", fh->get_name ()); + n = -1; + } + if (n <= 0) + ReleaseMutex (guard_mutex); /* Oops. We lost the race. */ } if (n < 0) |