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authorMarc-André Lureau <marcandre.lureau@redhat.com>2018-12-06 00:37:33 +0400
committerMarkus Armbruster <armbru@redhat.com>2018-12-12 09:55:57 +0100
commit9ac3788b0be368e2826a8e9adadc1ada87d89273 (patch)
treea91ff23c71736ba9d91377b0a066ab6fa71364fc
parentef12a703b7d4894a851cbf3e94cca8fa25fc43f2 (diff)
char: add a QEMU_CHAR_FEATURE_GCONTEXT flag
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 <marcandre.lureau@redhat.com> Message-Id: <20181205203737.9011-4-marcandre.lureau@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
-rw-r--r--chardev/char.c11
-rw-r--r--include/chardev/char.h3
2 files changed, 14 insertions, 0 deletions
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;