From nobody Fri May 16 01:02:13 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; envelope-from=libvir-list-bounces@redhat.com; helo=mx1.redhat.com; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=libvir-list-bounces@redhat.com Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mx.zohomail.com with SMTPS id 1503573840379112.32438229069362; Thu, 24 Aug 2017 04:24:00 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 912C1C0587C9; Thu, 24 Aug 2017 11:23:58 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6FE9D7D512; Thu, 24 Aug 2017 11:23:58 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 39E14180610B; Thu, 24 Aug 2017 11:23:58 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id v7OBNhnZ010870 for ; Thu, 24 Aug 2017 07:23:43 -0400 Received: by smtp.corp.redhat.com (Postfix) id DF13E7B55C; Thu, 24 Aug 2017 11:23:43 +0000 (UTC) Received: from beluga.usersys.redhat.com (unknown [10.43.2.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4042C7B52C; Thu, 24 Aug 2017 11:23:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 912C1C0587C9 Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=libvir-list-bounces@redhat.com From: Erik Skultety To: libvir-list@redhat.com Date: Thu, 24 Aug 2017 13:23:31 +0200 Message-Id: <99af32dc75bfc0891e4e06dbf9cc59f5395e4bdc.1503573079.git.eskultet@redhat.com> In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-loop: libvir-list@redhat.com Cc: Erik Skultety Subject: [libvirt] [PATCH v3 5/6] util: Introduce virFileWaitForAccess X-BeenThere: libvir-list@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Development discussions about the libvirt library & tools List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: libvir-list-bounces@redhat.com Errors-To: libvir-list-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 24 Aug 2017 11:23:59 +0000 (UTC) X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" Since we have a number of places where we workaround timing issues with devices, attributes (files in general) not being available at the time of processing them by calling usleep in a loop for a fixed number of tries, we could as well have a utility function that would do that. Therefore we won't have to duplicate this ugly workaround even more. Signed-off-by: Erik Skultety --- src/libvirt_private.syms | 1 + src/util/virfile.c | 29 +++++++++++++++++++++++++++++ src/util/virfile.h | 2 ++ 3 files changed, 32 insertions(+) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 2149b11b7..b9fb54a79 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1724,6 +1724,7 @@ virFileStripSuffix; virFileTouch; virFileUnlock; virFileUpdatePerm; +virFileWaitForAccess; virFileWrapperFdClose; virFileWrapperFdFree; virFileWrapperFdNew; diff --git a/src/util/virfile.c b/src/util/virfile.c index 2f28e83f4..15b46bcdd 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -4166,3 +4166,32 @@ virFileReadValueString(char **value, const char *for= mat, ...) VIR_FREE(str); return ret; } + + +/** + * virFileWaitForAccess: + * @path: absolute path to a sysfs attribute (can be a symlink) + * @ms: how long to wait (in milliseconds) + * @tries: how many times should we try to wait for @path to become access= ible + * + * Checks the existence of @path. In case the file defined by @path + * doesn't exist, we wait for it to appear in @ms milliseconds (for up to + * @tries attempts). + * + * Returns 0 on success, -1 on error, setting errno appropriately. + */ +int +virFileWaitForAccess(const char *path, size_t ms, size_t tries) +{ + errno =3D 0; + + /* wait for @path to be accessible in @ms milliseconds, up to @tries */ + while (tries-- > 0 && !virFileExists(path)) { + if (tries =3D=3D 0 || errno !=3D ENOENT) + return -1; + + usleep(ms * 1000); + } + + return 0; +} diff --git a/src/util/virfile.h b/src/util/virfile.h index 57ceb8072..42630ebb5 100644 --- a/src/util/virfile.h +++ b/src/util/virfile.h @@ -347,6 +347,8 @@ int virFileReadValueScaledInt(unsigned long long *value= , const char *format, ... int virFileReadValueString(char **value, const char *format, ...) ATTRIBUTE_FMT_PRINTF(2, 3); =20 +int virFileWaitForAccess(const char *path, size_t ms, size_t tries); + =20 int virFileInData(int fd, int *inData, --=20 2.13.3 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list