From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35815) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dT5bb-0005ON-CJ for qemu-devel@nongnu.org; Thu, 06 Jul 2017 08:10:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dT5bX-0004go-Bc for qemu-devel@nongnu.org; Thu, 06 Jul 2017 08:09:59 -0400 Received: from mail-ve1eur01on0121.outbound.protection.outlook.com ([104.47.1.121]:61440 helo=EUR01-VE1-obe.outbound.protection.outlook.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dT5bW-0004gR-Ve for qemu-devel@nongnu.org; Thu, 06 Jul 2017 08:09:55 -0400 From: Anton Nefedov Date: Thu, 6 Jul 2017 15:08:51 +0300 Message-ID: <1499342940-56739-5-git-send-email-anton.nefedov@virtuozzo.com> In-Reply-To: <1499342940-56739-1-git-send-email-anton.nefedov@virtuozzo.com> References: <1499342940-56739-1-git-send-email-anton.nefedov@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH v6 04/13] char: forbid direct chardevice access for hotswap devices List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: den@virtuozzo.com, pbonzini@redhat.com, marcandre.lureau@redhat.com, amit@kernel.org, mst@redhat.com, Anton Nefedov qemu_chr_fe_get_driver() is unsafe, frontends with hotswap support should not access CharDriver ptr directly as CharDriver might change. Signed-off-by: Anton Nefedov Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Marc-Andr=C3=A9 Lureau --- include/chardev/char-fe.h | 10 ++++++++++ chardev/char-fe.c | 7 +++++++ 2 files changed, 17 insertions(+) diff --git a/include/chardev/char-fe.h b/include/chardev/char-fe.h index 9f38060..588abed 100644 --- a/include/chardev/char-fe.h +++ b/include/chardev/char-fe.h @@ -46,10 +46,20 @@ void qemu_chr_fe_deinit(CharBackend *b, bool del); * * Returns the driver associated with a CharBackend or NULL if no * associated Chardev. + * Note: avoid this function as the driver should never be accessed direct= ly, + * especially by the frontends that support chardevice hotswap. + * Consider qemu_chr_fe_backend_connected() to check for driver exis= tence */ Chardev *qemu_chr_fe_get_driver(CharBackend *be); =20 /** + * @qemu_chr_fe_backend_connected: + * + * Returns true if there is a chardevice associated with @be. + */ +bool qemu_chr_fe_backend_connected(CharBackend *be); + +/** * @qemu_chr_fe_set_handlers: * @b: a CharBackend * @fd_can_read: callback to get the amount of data the frontend may diff --git a/chardev/char-fe.c b/chardev/char-fe.c index 7054863..de5ba3c 100644 --- a/chardev/char-fe.c +++ b/chardev/char-fe.c @@ -179,9 +179,16 @@ void qemu_chr_fe_printf(CharBackend *be, const char *f= mt, ...) =20 Chardev *qemu_chr_fe_get_driver(CharBackend *be) { + /* this is unsafe for the users that support chardev hotswap */ + assert(be->chr_be_change =3D=3D NULL); return be->chr; } =20 +bool qemu_chr_fe_backend_connected(CharBackend *be) +{ + return !!be->chr; +} + bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp) { int tag =3D 0; --=20 2.7.4