Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:53550 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751426AbdHGTJP (ORCPT ); Mon, 7 Aug 2017 15:09:15 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7F6A36869C for ; Mon, 7 Aug 2017 19:09:15 +0000 (UTC) From: Scott Mayhew To: steved@redhat.com Cc: linux-nfs@vger.kernel.org Subject: [nfs-utils PATCH] idmapd: daemonize earlier Date: Mon, 7 Aug 2017 15:09:14 -0400 Message-Id: <20170807190914.7422-1-smayhew@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: daemon_init() calls closeall() to close any "unneeded" file descriptors. This causes the following issue with idmapd on systems that are configured to have SSSD handle local users and groups: 1. During startup, rpc.idmapd calls getpwnam("nobody") and getgrnam("nobody") 2. sss_nss_mc_get{pw,gr}nam from libnss_sss open the cache files for users and groups and store the fd's in a struct sss_cli_mc_ctx. The passwd cache is fd 3 and the group cache is fd 4. 3. idmapd calls daemon_init() which sets fd's 0, 1, and 2 to /dev/null and fd 3 to the write end of the pipe that the child uses to report it's startup status. It then closes all fd's >= 4. 4. idmapd then calls event_init() which leads to epoll_create1() which returns 4 as the epoll fd. 6. An NFSv4 mount request comes in from a client, triggering an nfsdcb callback. 7. idmapd calls getgrgid_r() which leads to a call to sss_nss_check_header() which determines that the cache needs to be reinitialized. sss_nss_mc_destroy_ctx() is called, which closes the ctx->fd which now corresponds to the epoll file rather than the group cache file. 8. event_dispatch() calls epoll_wait() with epfd=4, and -EBADF is returned. idmapd logs the following error and exits with a nonzero status: rpc.idmapd[650]: main: event_dispatch returns errno 9 (Bad file descriptor) Moving the deamon_init() call so that it happens before get{pw,gr}nam() fixes this. Signed-off-by: Scott Mayhew --- utils/idmapd/idmapd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/utils/idmapd/idmapd.c b/utils/idmapd/idmapd.c index c12e878..4cbe148 100644 --- a/utils/idmapd/idmapd.c +++ b/utils/idmapd/idmapd.c @@ -312,6 +312,8 @@ main(int argc, char **argv) strncat(pipefsdir, "/nfs", sizeof(pipefsdir)); + daemon_init(fg); + if ((pw = getpwnam(nobodyuser)) == NULL) errx(1, "Could not find user \"%s\"", nobodyuser); nobodyuid = pw->pw_uid; @@ -328,8 +330,6 @@ main(int argc, char **argv) if (nfs4_init_name_mapping(conf_path)) errx(1, "Unable to create name to user id mappings."); - daemon_init(fg); - event_init(); if (verbose > 0) -- 2.9.4