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Tue, 25 Aug 2020 15:14:23 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 9382D112D737; Tue, 25 Aug 2020 17:14:21 +0200 (CEST) From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Subject: Re: [PATCH v4 3/6] util: add Error object for qemu_open_internal error reporting References: <20200821172105.608752-1-berrange@redhat.com> <20200821172105.608752-4-berrange@redhat.com> Date: Tue, 25 Aug 2020 17:14:21 +0200 In-Reply-To: <20200821172105.608752-4-berrange@redhat.com> ("Daniel P. =?utf-8?Q?Berrang=C3=A9=22's?= message of "Fri, 21 Aug 2020 18:21:02 +0100") Message-ID: <87wo1mbvw2.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=205.139.110.61; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/25 01:35:36 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.958, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Max Reitz , qemu-devel@nongnu.org, qemu-block@nongnu.org, Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Daniel P. Berrang=C3=A9 writes: > Instead of relying on the limited information from errno, we can now > also provide detailed error messages. The more detailed error messages are currently always ignored, but the next patches will fix that. > Signed-off-by: Daniel P. Berrang=C3=A9 > --- > util/osdep.c | 21 +++++++++++++++++++-- > 1 file changed, 19 insertions(+), 2 deletions(-) > > diff --git a/util/osdep.c b/util/osdep.c > index 9ff92551e7..9c7118d3cb 100644 > --- a/util/osdep.c > +++ b/util/osdep.c > @@ -284,7 +284,7 @@ int qemu_lock_fd_test(int fd, int64_t start, int64_t = len, bool exclusive) > * Opens a file with FD_CLOEXEC set > */ > static int > -qemu_open_internal(const char *name, int flags, mode_t mode) > +qemu_open_internal(const char *name, int flags, mode_t mode, Error **err= p) > { > int ret; > =20 > @@ -298,24 +298,31 @@ qemu_open_internal(const char *name, int flags, mod= e_t mode) > =20 > fdset_id =3D qemu_parse_fdset(fdset_id_str); > if (fdset_id =3D=3D -1) { > + error_setg(errp, "Could not parse fdset %s", name); > errno =3D EINVAL; > return -1; > } > =20 > fd =3D monitor_fdset_get_fd(fdset_id, flags); > if (fd < 0) { > + error_setg_errno(errp, -fd, "Could not acquire FD for %s fla= gs %x", > + name, flags); > errno =3D -fd; > return -1; > } > =20 > dupfd =3D qemu_dup_flags(fd, flags); > if (dupfd =3D=3D -1) { > + error_setg_errno(errp, errno, "Could not dup FD for %s flags= %x", > + name, flags); > return -1; > } > =20 > ret =3D monitor_fdset_dup_fd_add(fdset_id, dupfd); > if (ret =3D=3D -1) { > close(dupfd); > + error_setg(errp, "Could not save FD for %s flags %x", > + name, flags); Can this happen? > errno =3D EINVAL; > return -1; > } > @@ -336,6 +343,16 @@ qemu_open_internal(const char *name, int flags, mode= _t mode) > } > #endif /* ! O_CLOEXEC */ > =20 > + if (ret =3D=3D -1) { > + const char *action =3D "open"; > + if (flags & O_CREAT) { > + action =3D "create"; > + } > + error_setg_errno(errp, errno, "Could not %s '%s' flags 0x%x", > + action, name, flags); Not a good user experience: Could not open '/etc/shadow' flags 0x0: Permission denied Better: Could not open '/etc/shadow' for reading: Permission denied Are you sure flags other than the access mode (O_RDONLY, O_WRONLY, O_RDWR) must be included in the error message? If you must report flags in hexadecimal, then please reporting them more consistently. Right now you have for %s flags 0x%x '%s' flags %x Perhaps '%s' with flags 0x%x > + } > + > + > return ret; > } > =20 > @@ -352,7 +369,7 @@ int qemu_open_old(const char *name, int flags, ...) > } > va_end(ap); > =20 > - ret =3D qemu_open_internal(name, flags, mode); > + ret =3D qemu_open_internal(name, flags, mode, NULL); > =20 > #ifdef O_DIRECT > if (ret =3D=3D -1 && errno =3D=3D EINVAL && (flags & O_DIRECT)) {