From owner-svn-src-stable-12@freebsd.org Mon May 11 15:20:41 2020 Return-Path: Delivered-To: svn-src-stable-12@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 2F33B2E3DBE; Mon, 11 May 2020 15:20:41 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49LPlF0NYFz3Brc; Mon, 11 May 2020 15:20:41 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 0786120794; Mon, 11 May 2020 15:20:41 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 04BFKe9Q007017; Mon, 11 May 2020 15:20:40 GMT (envelope-from markj@FreeBSD.org) Received: (from markj@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 04BFKemo007013; Mon, 11 May 2020 15:20:40 GMT (envelope-from markj@FreeBSD.org) Message-Id: <202005111520.04BFKemo007013@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: markj set sender to markj@FreeBSD.org using -f From: Mark Johnston Date: Mon, 11 May 2020 15:20:40 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r360897 - in stable/12: lib/libc/sys sys/kern X-SVN-Group: stable-12 X-SVN-Commit-Author: markj X-SVN-Commit-Paths: in stable/12: lib/libc/sys sys/kern X-SVN-Commit-Revision: 360897 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable-12@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: SVN commit messages for only the 12-stable src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 May 2020 15:20:41 -0000 Author: markj Date: Mon May 11 15:20:40 2020 New Revision: 360897 URL: https://svnweb.freebsd.org/changeset/base/360897 Log: MFC r360380: Fix handling of EV_EOF for named pipes. PR: 203366, 224615, 246350 Modified: stable/12/lib/libc/sys/kqueue.2 stable/12/sys/kern/sys_pipe.c Directory Properties: stable/12/ (props changed) Modified: stable/12/lib/libc/sys/kqueue.2 ============================================================================== --- stable/12/lib/libc/sys/kqueue.2 Mon May 11 15:20:05 2020 (r360896) +++ stable/12/lib/libc/sys/kqueue.2 Mon May 11 15:20:40 2020 (r360897) @@ -24,7 +24,7 @@ .\" .\" $FreeBSD$ .\" -.Dd April 21, 2020 +.Dd April 27, 2020 .Dt KQUEUE 2 .Os .Sh NAME @@ -323,8 +323,7 @@ When the last writer disconnects, the filter will set .Dv EV_EOF in .Va flags . -This may be cleared by passing in -.Dv EV_CLEAR , +This will be cleared by the filter when a new writer connects, at which point the filter will resume waiting for data to become available before returning. @@ -343,9 +342,10 @@ For sockets, pipes and fifos, .Va data will contain the amount of space remaining in the write buffer. -The filter will set EV_EOF when the reader disconnects, and for -the fifo case, this may be cleared by use of -.Dv EV_CLEAR . +The filter will set +.Dv EV_EOF +when the reader disconnects, and for the fifo case, this will be cleared +when a new reader connects. Note that this filter is not supported for vnodes or BPF devices. .Pp For sockets, the low water mark and socket error handling is Modified: stable/12/sys/kern/sys_pipe.c ============================================================================== --- stable/12/sys/kern/sys_pipe.c Mon May 11 15:20:05 2020 (r360896) +++ stable/12/sys/kern/sys_pipe.c Mon May 11 15:20:40 2020 (r360897) @@ -826,7 +826,12 @@ unlocked_error: } } - if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF) + /* + * Only wake up writers if there was actually something read. + * Otherwise, when calling read(2) at EOF, a spurious wakeup occurs. + */ + if (nread > 0 && + rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt >= PIPE_BUF) pipeselwakeup(rpipe); PIPE_UNLOCK(rpipe); @@ -1728,48 +1733,54 @@ filt_pipedetach(struct knote *kn) static int filt_piperead(struct knote *kn, long hint) { + struct file *fp = kn->kn_fp; struct pipe *rpipe = kn->kn_hook; - struct pipe *wpipe = rpipe->pipe_peer; - int ret; PIPE_LOCK_ASSERT(rpipe, MA_OWNED); kn->kn_data = rpipe->pipe_buffer.cnt; if (kn->kn_data == 0) kn->kn_data = rpipe->pipe_map.cnt; - if ((rpipe->pipe_state & PIPE_EOF) || - wpipe->pipe_present != PIPE_ACTIVE || - (wpipe->pipe_state & PIPE_EOF)) { + if ((rpipe->pipe_state & PIPE_EOF) != 0 && + ((rpipe->pipe_state & PIPE_NAMED) == 0 || + fp->f_pipegen != rpipe->pipe_wgen)) { kn->kn_flags |= EV_EOF; return (1); } - ret = kn->kn_data > 0; - return ret; + kn->kn_flags &= ~EV_EOF; + return (kn->kn_data > 0); } /*ARGSUSED*/ static int filt_pipewrite(struct knote *kn, long hint) { - struct pipe *wpipe; + struct pipe *wpipe = kn->kn_hook; /* * If this end of the pipe is closed, the knote was removed from the * knlist and the list lock (i.e., the pipe lock) is therefore not held. */ - wpipe = kn->kn_hook; + if (wpipe->pipe_present == PIPE_ACTIVE || + (wpipe->pipe_state & PIPE_NAMED) != 0) { + PIPE_LOCK_ASSERT(wpipe, MA_OWNED); + + if (wpipe->pipe_state & PIPE_DIRECTW) { + kn->kn_data = 0; + } else if (wpipe->pipe_buffer.size > 0) { + kn->kn_data = wpipe->pipe_buffer.size - + wpipe->pipe_buffer.cnt; + } else { + kn->kn_data = PIPE_BUF; + } + } + if (wpipe->pipe_present != PIPE_ACTIVE || (wpipe->pipe_state & PIPE_EOF)) { - kn->kn_data = 0; kn->kn_flags |= EV_EOF; return (1); } - PIPE_LOCK_ASSERT(wpipe, MA_OWNED); - kn->kn_data = (wpipe->pipe_buffer.size > 0) ? - (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) : PIPE_BUF; - if (wpipe->pipe_state & PIPE_DIRECTW) - kn->kn_data = 0; - + kn->kn_flags &= ~EV_EOF; return (kn->kn_data >= PIPE_BUF); }