From 9ac3788b0be368e2826a8e9adadc1ada87d89273 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Thu, 6 Dec 2018 00:37:33 +0400 Subject: [PATCH] char: add a QEMU_CHAR_FEATURE_GCONTEXT flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit QEMU_CHAR_FEATURE_GCONTEXT declares the character device can switch GMainContext. Assert we don't switch context when the character device doesn't provide this feature. Character device users must not violate this restriction. In particular, user configurations that violate them must be rejected. Existing frontend that rely on context switching would now assert() if the backend doesn't allow it (instead of silently producing undesired events in the default context). Following patches improve the situation by reporting an error earlier instead, on the frontend side. Signed-off-by: Marc-André Lureau Message-Id: <20181205203737.9011-4-marcandre.lureau@redhat.com> Signed-off-by: Markus Armbruster --- chardev/char.c | 11 +++++++++++ include/chardev/char.h | 3 +++ 2 files changed, 14 insertions(+) diff --git a/chardev/char.c b/chardev/char.c index 152dde5327..ccba36bafb 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -193,6 +193,8 @@ void qemu_chr_be_update_read_handlers(Chardev *s, { ChardevClass *cc = CHARDEV_GET_CLASS(s); + assert(qemu_chr_has_feature(s, QEMU_CHAR_FEATURE_GCONTEXT) + || !context); s->gcontext = context; if (cc->chr_update_read_handler) { cc->chr_update_read_handler(s); @@ -240,6 +242,15 @@ static void char_init(Object *obj) chr->logfd = -1; qemu_mutex_init(&chr->chr_write_lock); + + /* + * Assume if chr_update_read_handler is implemented it will + * take the updated gcontext into account. + */ + if (CHARDEV_GET_CLASS(chr)->chr_update_read_handler) { + qemu_chr_set_feature(chr, QEMU_CHAR_FEATURE_GCONTEXT); + } + } static int null_chr_write(Chardev *chr, const uint8_t *buf, int len) diff --git a/include/chardev/char.h b/include/chardev/char.h index 7becd8c80c..014566c3de 100644 --- a/include/chardev/char.h +++ b/include/chardev/char.h @@ -47,6 +47,9 @@ typedef enum { QEMU_CHAR_FEATURE_FD_PASS, /* Whether replay or record mode is enabled */ QEMU_CHAR_FEATURE_REPLAY, + /* Whether the gcontext can be changed after calling + * qemu_chr_be_update_read_handlers() */ + QEMU_CHAR_FEATURE_GCONTEXT, QEMU_CHAR_FEATURE_LAST, } ChardevFeature;