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3baf755)
Don't open with O_NONBLOCK, instead open in blocking mode and set
O_NONBLOCK subsequently with fcntl(). This appears to fix the
problems with FIFOs.
Pick one of the following:
- the semantics as implemented by Linux & Solaris is broken
- the POSIX semantics is broken
- our expectation that things should behave sensibly is unreasonable
/*
* (c) The GRASP/AQUA Project, Glasgow University, 1994-1998
*
/*
* (c) The GRASP/AQUA Project, Glasgow University, 1994-1998
*
- * $Id: openFile.c,v 1.16 2000/04/12 17:33:16 simonmar Exp $
+ * $Id: openFile.c,v 1.17 2000/05/11 13:15:38 simonmar Exp $
*
* openFile Runtime Support
*/
*
* openFile Runtime Support
*/
switch (how) {
case OPENFILE_APPEND:
switch (how) {
case OPENFILE_APPEND:
- oflags = O_NONBLOCK | O_WRONLY | O_NOCTTY | O_APPEND;
+ oflags = O_WRONLY | O_NOCTTY | O_APPEND;
for_writing = 1;
flags |= FILEOBJ_WRITE;
break;
case OPENFILE_WRITE:
for_writing = 1;
flags |= FILEOBJ_WRITE;
break;
case OPENFILE_WRITE:
- oflags = O_NONBLOCK | O_WRONLY | O_NOCTTY;
+ oflags = O_WRONLY | O_NOCTTY;
flags |= FILEOBJ_WRITE;
for_writing = 1;
break;
case OPENFILE_READ_ONLY:
flags |= FILEOBJ_WRITE;
for_writing = 1;
break;
case OPENFILE_READ_ONLY:
- oflags = O_NONBLOCK | O_RDONLY | O_NOCTTY;
+ oflags = O_RDONLY | O_NOCTTY;
flags |= FILEOBJ_READ;
for_writing = 0;
break;
case OPENFILE_READ_WRITE:
flags |= FILEOBJ_READ;
for_writing = 0;
break;
case OPENFILE_READ_WRITE:
- oflags = O_NONBLOCK | O_RDWR | O_NOCTTY;
+ oflags = O_RDWR | O_NOCTTY;
flags |= FILEOBJ_READ | FILEOBJ_WRITE;
for_writing = 1;
break;
flags |= FILEOBJ_READ | FILEOBJ_WRITE;
for_writing = 1;
break;
- /* Make sure that we aren't looking at a directory */
+ /* Set non-blocking mode *after* the open. The reason is that
+ * when reading from a FIFO, if we open in non-blocking mode
+ * then any reads from the FIFO will return EOF straight away
+ * without waiting for a writing process. If we set O_NONBLOCK
+ * after doing the open, then we apparently get to wait for a
+ * writer. This broken behaviour has been observed on both Linux
+ * & Solaris. --SDM
+ */
+ fcntl(fd, F_SETFL, oflags | O_NONBLOCK);
+ /* Make sure that we aren't looking at a directory */
while (fstat(fd, &sb) < 0) {
/* highly unlikely */
if (errno != EINTR) {
while (fstat(fd, &sb) < 0) {
/* highly unlikely */
if (errno != EINTR) {