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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9A855C3DA49 for ; Tue, 16 Jul 2024 09:54:09 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sTesZ-00056e-PY; Tue, 16 Jul 2024 05:53:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sTesX-0004z7-Tb for qemu-devel@nongnu.org; Tue, 16 Jul 2024 05:53:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sTesW-0001O5-1x for qemu-devel@nongnu.org; Tue, 16 Jul 2024 05:53:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1721123621; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=GEryiX8Jb99v01V+6ioR/c/If5CdG8JXsRMZBeiNBYI=; b=FHYosHsIdK1zJGVRAnNlRAUxaruAi5smsZIiwOGNAWyOv4wDC4ci+B4/ItPozhDwH5Xflw fGpK5YykdMoGv+sMysfsteR0rB3sxowraoMqXpRAqD4A6rmV7YYTJUeiS1toPHLDNY7deS AaU8+Z+ULthLYYc1eyfjxdPyxbnVeJc= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-207-e_Vi-DfHPWydM0C7JR6fXQ-1; Tue, 16 Jul 2024 05:53:37 -0400 X-MC-Unique: e_Vi-DfHPWydM0C7JR6fXQ-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9319819560A3; Tue, 16 Jul 2024 09:53:35 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.46]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C33B819560B2; Tue, 16 Jul 2024 09:53:29 +0000 (UTC) Date: Tue, 16 Jul 2024 10:53:26 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Akihiko Odaki Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Yuval Shaia , Marcel Apfelbaum , Konstantin Kostiuk , Michael Roth , Paolo Bonzini , Fam Zheng , "Dr . David Alan Gilbert" , Stefan Hajnoczi , Gerd Hoffmann , Stefan Weil , Yan Vugenfirer Subject: Re: [PATCH v4 1/7] util: Introduce qemu_get_runtime_dir() Message-ID: References: <20240716-run-v4-0-5f7a29631168@daynix.com> <20240716-run-v4-1-5f7a29631168@daynix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240716-run-v4-1-5f7a29631168@daynix.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Jul 16, 2024 at 04:27:31PM +0900, Akihiko Odaki wrote: > qemu_get_runtime_dir() returns a dynamically allocated directory path > that is appropriate for storing runtime files. It corresponds to "run" > directory in Unix. > > With a tree-wide search, it was found that there are several cases > where such a functionality is implemented so let's have one as a common > utlity function. > > A notable feature of qemu_get_runtime_dir() is that it uses > $XDG_RUNTIME_DIR if available. While the function is often called by > executables which requires root privileges, it is still possible that > they are called from a user without privilege to write the system > runtime directory. In fact, I decided to write this patch when I ran > virtiofsd in a Linux namespace created by a normal user and realized > it tries to write the system runtime directory, not writable in this > case. $XDG_RUNTIME_DIR should provide a writable directory in such > cases. > > This function does not use qemu_get_local_state_dir() or its logic > for Windows. Actually the implementation of qemu_get_local_state_dir() > for Windows seems not right as it calls g_get_system_data_dirs(), > which refers to $XDG_DATA_DIRS. In Unix terminology, it is basically > "/usr/share", not "/var", which qemu_get_local_state_dir() is intended > to provide. Instead, this function try to use the following in order: > - $XDG_RUNTIME_DIR > - LocalAppData folder > - get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR "/run") > > This function does not use g_get_user_runtime_dir() either as it > falls back to g_get_user_cache_dir() when $XDG_DATA_DIRS is not > available. In the case, we rather use: > get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR "/run") > > Signed-off-by: Akihiko Odaki > Message-Id: <20230921075425.16738-2-akihiko.odaki@daynix.com> > --- > include/qemu/osdep.h | 12 ++++++++++++ > util/oslib-posix.c | 11 +++++++++++ > util/oslib-win32.c | 26 ++++++++++++++++++++++++++ > 3 files changed, 49 insertions(+) > > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h > index 191916f38e6d..fe8609fc1375 100644 > --- a/include/qemu/osdep.h > +++ b/include/qemu/osdep.h > @@ -670,6 +670,18 @@ void qemu_set_cloexec(int fd); > */ > char *qemu_get_local_state_dir(void); > > +/** > + * qemu_get_runtime_dir: > + * > + * Return a dynamically allocated directory path that is appropriate for storing > + * runtime files. It corresponds to "run" directory in Unix, and uses > + * $XDG_RUNTIME_DIR if available. > + * > + * The caller is responsible for releasing the value returned with g_free() > + * after use. > + */ > +char *qemu_get_runtime_dir(void); > + > /** > * qemu_getauxval: > * @type: the auxiliary vector key to lookup > diff --git a/util/oslib-posix.c b/util/oslib-posix.c > index e76441695bdc..9599509a9aa7 100644 > --- a/util/oslib-posix.c > +++ b/util/oslib-posix.c > @@ -278,6 +278,17 @@ qemu_get_local_state_dir(void) > return get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR); > } > > +char * > +qemu_get_runtime_dir(void) > +{ > + char *env = getenv("XDG_RUNTIME_DIR"); > + if (env) { > + return g_strdup(env); > + } > + > + return get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR "/run"); > +} I'm not convinced this is the correct logic to be following. In the cover letter you mention not using g_get_user_runtime_dir() because it falls back to XDG_CACHE_HOME, and we need to fallback to LOCALSTATEDIR/run. This is not right for normal users though, where falling back to LOCALSTATEDIR/run is always wrong, as it won't be writable - the g_get_user_runtime_dir() fallback is desirable for non-root users. IMHO we should be doing something more like this #ifndef WIN32 if (geteuid() == 0) { return get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR "/run"); } else { #endif return g_get_user_runtime_dir(); #ifndef WIN32 } #endif > + > void qemu_set_tty_echo(int fd, bool echo) > { > struct termios tty; > diff --git a/util/oslib-win32.c b/util/oslib-win32.c > index b623830d624f..8c5a02ee881d 100644 > --- a/util/oslib-win32.c > +++ b/util/oslib-win32.c > @@ -27,6 +27,8 @@ > */ > > #include "qemu/osdep.h" > +#include > +#include > #include > #include "qapi/error.h" > #include "qemu/main-loop.h" > @@ -237,6 +239,30 @@ qemu_get_local_state_dir(void) > return g_strdup(data_dirs[0]); > } > > +char * > +qemu_get_runtime_dir(void) > +{ > + size_t size = GetEnvironmentVariableA("XDG_RUNTIME_DIR", NULL, 0); > + if (size) { > + char *env = g_malloc(size); > + GetEnvironmentVariableA("XDG_RUNTIME_DIR", env, size); > + return env; > + } > + > + PWSTR wpath; > + const wchar_t *cwpath; > + if (!SHGetKnownFolderPath(&FOLDERID_LocalAppData, KF_FLAG_DEFAULT, NULL, &wpath)) { > + cwpath = wpath; > + size = wcsrtombs(NULL, &cwpath, 0, &(mbstate_t){0}) + 1; > + char *path = g_malloc(size); > + wcsrtombs(path, &cwpath, size, &(mbstate_t){0}); > + CoTaskMemFree(wpath); > + return path; > + } > + > + return get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR "/run"); > +} > + > void qemu_set_tty_echo(int fd, bool echo) > { > HANDLE handle = (HANDLE)_get_osfhandle(fd); > > -- > 2.45.2 > > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|