From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DEA19C433E3 for ; Sat, 18 Jul 2020 15:55:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91DC82076A for ; Sat, 18 Jul 2020 15:55:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="hcFQI4dq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726411AbgGRPzD (ORCPT ); Sat, 18 Jul 2020 11:55:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726155AbgGRPzC (ORCPT ); Sat, 18 Jul 2020 11:55:02 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2CA8C0619D2 for ; Sat, 18 Jul 2020 08:55:02 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id ABA1A6193; Sat, 18 Jul 2020 11:55:01 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org ABA1A6193 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1595087701; bh=3bSX3vn3S13LjtLNsUZONdchjIfYTNblRp5W7zzgYAM=; h=Date:To:Cc:Subject:References:In-Reply-To:From:From; b=hcFQI4dq2LzXXI1yQNS9DPdd/kuvQo3mn8HURoyIFogNimQVMHlATYHHF7J1jtNWb nPPFU6Gi8VekY3/tvKwiT1VqNI+xeV/rXVrofJDj7Buj3v1SzHqSoVCVSSnTpbO/Jp bvlCMAMfuApf+V06+VYrcShcqBqVRXg0i9KIhUoA= Date: Sat, 18 Jul 2020 11:55:01 -0400 To: Doug Nazar Cc: linux-nfs@vger.kernel.org Subject: Re: [PATCH 11/11] svcgssd: Wait for nullrpc channel if not available Message-ID: <20200718155501.GB27817@fieldses.org> References: <20200718092421.31691-1-nazard@nazar.ca> <20200718092421.31691-12-nazard@nazar.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200718092421.31691-12-nazard@nazar.ca> User-Agent: Mutt/1.5.21 (2010-09-15) From: bfields@fieldses.org (J. Bruce Fields) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Sat, Jul 18, 2020 at 05:24:21AM -0400, Doug Nazar wrote: > Signed-off-by: Doug Nazar So, is there a race here that could result in a hang, and has anyone seen it in practice? Just curious. Thanks for doing this.--b. > --- > utils/gssd/svcgssd.c | 99 +++++++++++++++++++++++++++++++++++--------- > 1 file changed, 80 insertions(+), 19 deletions(-) > > diff --git a/utils/gssd/svcgssd.c b/utils/gssd/svcgssd.c > index 3155a2f9..3ab2100b 100644 > --- a/utils/gssd/svcgssd.c > +++ b/utils/gssd/svcgssd.c > @@ -67,9 +67,14 @@ > #include "misc.h" > #include "svcgssd_krb5.h" > > -struct state_paths etab; > +struct state_paths etab; /* from cacheio.c */ > static bool signal_received = false; > static struct event_base *evbase = NULL; > +static int nullrpc_fd = -1; > +static struct event *nullrpc_event = NULL; > +static struct event *wait_event = NULL; > + > +#define NULLRPC_FILE "/proc/net/rpc/auth.rpcsec.init/channel" > > static void > sig_die(int signal) > @@ -118,6 +123,66 @@ svcgssd_nullrpc_cb(int fd, short UNUSED(which), void *UNUSED(data)) > handle_nullreq(lbuf); > } > > +static void > +svcgssd_nullrpc_close(void) > +{ > + if (nullrpc_event) { > + printerr(2, "closing nullrpc channel %s\n", NULLRPC_FILE); > + event_free(nullrpc_event); > + nullrpc_event = NULL; > + } > + if (nullrpc_fd != -1) { > + close(nullrpc_fd); > + nullrpc_fd = -1; > + } > +} > + > +static void > +svcgssd_nullrpc_open(void) > +{ > + nullrpc_fd = open(NULLRPC_FILE, O_RDWR); > + if (nullrpc_fd < 0) { > + printerr(0, "failed to open %s: %s\n", > + NULLRPC_FILE, strerror(errno)); > + return; > + } > + nullrpc_event = event_new(evbase, nullrpc_fd, EV_READ | EV_PERSIST, > + svcgssd_nullrpc_cb, NULL); > + if (!nullrpc_event) { > + printerr(0, "failed to create event for %s: %s\n", > + NULLRPC_FILE, strerror(errno)); > + close(nullrpc_fd); > + nullrpc_fd = -1; > + return; > + } > + event_add(nullrpc_event, NULL); > + printerr(2, "opened nullrpc channel %s\n", NULLRPC_FILE); > +} > + > +static void > +svcgssd_wait_cb(int UNUSED(fd), short UNUSED(which), void *UNUSED(data)) > +{ > + static int times = 0; > + int rc; > + > + rc = access(NULLRPC_FILE, R_OK | W_OK); > + if (rc != 0) { > + struct timeval t = {times < 10 ? 1 : 10, 0}; > + times++; > + if (times % 30 == 0) > + printerr(2, "still waiting for nullrpc channel: %s\n", > + NULLRPC_FILE); > + evtimer_add(wait_event, &t); > + return; > + } > + > + svcgssd_nullrpc_open(); > + event_free(wait_event); > + wait_event = NULL; > +} > + > + > + > int > main(int argc, char *argv[]) > { > @@ -132,8 +197,6 @@ main(int argc, char *argv[]) > char *principal = NULL; > char *s; > int rc; > - int nullrpc_fd = -1; > - struct event *nullrpc_event = NULL; > > conf_init_file(NFS_CONFFILE); > > @@ -250,22 +313,19 @@ main(int argc, char *argv[]) > } > } > > -#define NULLRPC_FILE "/proc/net/rpc/auth.rpcsec.init/channel" > - > - nullrpc_fd = open(NULLRPC_FILE, O_RDWR); > - if (nullrpc_fd < 0) { > - printerr(0, "failed to open %s: %s\n", > - NULLRPC_FILE, strerror(errno)); > - exit(1); > - } > - nullrpc_event = event_new(evbase, nullrpc_fd, EV_READ | EV_PERSIST, > - svcgssd_nullrpc_cb, NULL); > + svcgssd_nullrpc_open(); > if (!nullrpc_event) { > - printerr(0, "failed to create event for %s: %s\n", > - NULLRPC_FILE, strerror(errno)); > - exit(1); > + struct timeval t = {1, 0}; > + > + printerr(2, "waiting for nullrpc channel to appear\n"); > + wait_event = evtimer_new(evbase, svcgssd_wait_cb, NULL); > + if (!wait_event) { > + printerr(0, "ERROR: failed to create wait event: %s\n", > + strerror(errno)); > + exit(EXIT_FAILURE); > + } > + evtimer_add(wait_event, &t); > } > - event_add(nullrpc_event, NULL); > > daemon_ready(); > > @@ -275,8 +335,9 @@ main(int argc, char *argv[]) > if (rc < 0) > printerr(0, "event_base_dispatch() returned %i!\n", rc); > > - event_free(nullrpc_event); > - close(nullrpc_fd); > + svcgssd_nullrpc_close(); > + if (wait_event) > + event_free(wait_event); > > event_base_free(evbase); > > -- > 2.26.2