@@ -123,11 +123,10 @@ static int parse_chr(DeviceState *dev, const char *str, void **ptr)
if (chr == NULL) {
return -ENOENT;
}
- if (chr->avail_connections < 1) {
+ if (qemu_chr_fe_claim(chr) != 0) {
return -EEXIST;
}
*ptr = chr;
- --chr->avail_connections;
return 0;
}
@@ -140,7 +139,7 @@ static void release_chr(Object *obj, const char *name, void *opaque)
if (chr) {
qemu_chr_add_handlers(chr, NULL, NULL, NULL, NULL);
- ++chr->avail_connections;
+ qemu_chr_fe_release(chr);
}
}
@@ -188,6 +188,35 @@ int qemu_chr_fe_ioctl(CharDriverState *s, int cmd, void *arg);
int qemu_chr_fe_get_msgfd(CharDriverState *s);
/**
+ * @qemu_chr_fe_claim:
+ *
+ * Claim a backend before using it, should be called before calling
+ * qemu_chr_add_handlers().
+ *
+ * Returns: -1 if the backend is already in use by another frontend, 0 on
+ * success.
+ */
+int qemu_chr_fe_claim(CharDriverState *s);
+
+/**
+ * @qemu_chr_fe_claim_no_fail:
+ *
+ * Like qemu_chr_fe_claim, but will exit qemu with an error when the
+ * backend is already in use.
+ */
+void qemu_chr_fe_claim_no_fail(CharDriverState *s);
+
+/**
+ * @qemu_chr_fe_claim:
+ *
+ * Release a backend for use by another frontend.
+ *
+ * Returns: -1 if the backend is already in use by another frontend, 0 on
+ * success.
+ */
+void qemu_chr_fe_release(CharDriverState *s);
+
+/**
* @qemu_chr_be_can_write:
*
* Determine how much data the front end can currently accept. This function
@@ -3418,6 +3418,29 @@ int qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
return tag;
}
+int qemu_chr_fe_claim(CharDriverState *s)
+{
+ if (s->avail_connections < 1) {
+ return -1;
+ }
+ s->avail_connections--;
+ return 0;
+}
+
+void qemu_chr_fe_claim_no_fail(CharDriverState *s)
+{
+ if (qemu_chr_fe_claim(s) != 0) {
+ fprintf(stderr, "%s: error chardev \"%s\" already used\n",
+ __func__, s->label);
+ exit(1);
+ }
+}
+
+void qemu_chr_fe_release(CharDriverState *s)
+{
+ s->avail_connections++;
+}
+
void qemu_chr_delete(CharDriverState *chr)
{
QTAILQ_REMOVE(&chardevs, chr, next);
Add qemu_chr_fe_claim / _release helper functions for properly dealing with avail_connections. Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- hw/qdev-properties-system.c | 5 ++--- include/char/char.h | 29 +++++++++++++++++++++++++++++ qemu-char.c | 23 +++++++++++++++++++++++ 3 files changed, 54 insertions(+), 3 deletions(-)