diff options
| author | Todd C. Miller <millert@cvs.openbsd.org> | 2004-05-14 21:33:59 +0000 |
|---|---|---|
| committer | Todd C. Miller <millert@cvs.openbsd.org> | 2004-05-14 21:33:59 +0000 |
| commit | 8db5f8d29780629a4bf73ec55f434f2c774ec8b2 (patch) | |
| tree | 5b4896afc89a9caa2d76fa971f348e9e36fd51dd /sys/miscfs/fifofs | |
| parent | 40415f62a5f614d6d6b0b9a92882934895e42f1a (diff) | |
Fix a bug that occurs when a FIFO is opened for writing with
O_NONBLOCK set and there are no readers. Before returning ENXIO
fifo_open calls VOP_CLOSE (and hence fifo_close). However, since
fi_writers has not yet been incremented, when fifo_close decements
fi_writers it is one too few. This could cause qmail processes
to spin, consuming all the CPU.
Noticed by avsm@ and henning@, test case provided by claudio@, Ok pedro@
Diffstat (limited to 'sys/miscfs/fifofs')
| -rw-r--r-- | sys/miscfs/fifofs/fifo_vnops.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/sys/miscfs/fifofs/fifo_vnops.c b/sys/miscfs/fifofs/fifo_vnops.c index 157f00fd8e9..0ac5f3e37f0 100644 --- a/sys/miscfs/fifofs/fifo_vnops.c +++ b/sys/miscfs/fifofs/fifo_vnops.c @@ -1,4 +1,4 @@ -/* $OpenBSD: fifo_vnops.c,v 1.19 2004/03/02 04:42:52 tedu Exp $ */ +/* $OpenBSD: fifo_vnops.c,v 1.20 2004/05/14 21:33:58 millert Exp $ */ /* $NetBSD: fifo_vnops.c,v 1.18 1996/03/16 23:52:42 christos Exp $ */ /* @@ -191,18 +191,20 @@ fifo_open(v) rso->so_state |= SS_CANTRCVMORE; } if (ap->a_mode & FREAD) { - if (fip->fi_readers++ == 0) { + fip->fi_readers++; + if (fip->fi_readers == 1) { fip->fi_writesock->so_state &= ~SS_CANTSENDMORE; if (fip->fi_writers > 0) wakeup(&fip->fi_writers); } } if (ap->a_mode & FWRITE) { + fip->fi_writers++; if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) { error = ENXIO; goto bad; } - if (fip->fi_writers++ == 0) { + if (fip->fi_writers == 1) { fip->fi_readsock->so_state &= ~SS_CANTRCVMORE; if (fip->fi_readers > 0) wakeup(&fip->fi_readers); |