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| author | Christopher Faylor <me@cgf.cx> | 2001-11-03 03:32:27 +0000 |
|---|---|---|
| committer | Christopher Faylor <me@cgf.cx> | 2001-11-03 03:32:27 +0000 |
| commit | 243a041bd0164aa62813ac4ba5a1a02eb2db455b (patch) | |
| tree | af591a485215fcd4578be09cfabe6ff75b0782fe /winsup/cygwin/select.cc | |
| parent | 01432054cb24122d300f109d4d252a9c95835a9b (diff) | |
| download | newlib-243a041bd0164aa62813ac4ba5a1a02eb2db455b.zip newlib-243a041bd0164aa62813ac4ba5a1a02eb2db455b.tar.gz newlib-243a041bd0164aa62813ac4ba5a1a02eb2db455b.tar.bz2 | |
* dll_init.h (class dll_list): Reorder functions to avoid compiler "can't
inline" warnings.
* security.h (class cygsid): Ditto.
* sigproc.cc (get_proc_lock): Ditto.
* sigproc.h (class sigframe): Ditto.
* sync.h (class muto): Ditto.
* fhandler.h (fhandler_base::get_guard): Actually MAKE virtual as previously
indicated.
* pipe.cc (make_pipe): Remove extraneous set_errno.
* syscalls.cc (_open): Ditto.
* select.cc (peek_pipe): Need to check that there is still something to read
from the pipe after acquiring the mutex since another process/thread could have
eaten the input before we got to acquiring the lock. (Thanks to Nick Duffek
for this inspiration.)
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 1ba3ef3..78d1aaa 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) |