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authorHans de Goede <hdegoede@redhat.com>2013-03-27 20:29:39 +0100
committerAnthony Liguori <aliguori@us.ibm.com>2013-04-04 19:21:25 -0500
commit44c473decd4de5559487430f876de53c607b1e9d (patch)
tree8b00d24b4297565dd29de621891b38e32f1706a3
parent4dbb9ed3263e0f48282a2fc3d05099ba63e5b0e2 (diff)
qemu-char: Add qemu_chr_fe_claim / _release helper functions
Add qemu_chr_fe_claim / _release helper functions for properly dealing with avail_connections. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Message-id: 1364412581-3672-2-git-send-email-hdegoede@redhat.com Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
-rw-r--r--hw/qdev-properties-system.c5
-rw-r--r--include/char/char.h29
-rw-r--r--qemu-char.c23
3 files changed, 54 insertions, 3 deletions
diff --git a/hw/qdev-properties-system.c b/hw/qdev-properties-system.c
index d9934b5b9c..a22b155b6f 100644
--- a/hw/qdev-properties-system.c
+++ b/hw/qdev-properties-system.c
@@ -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);
}
}
diff --git a/include/char/char.h b/include/char/char.h
index 32c9999113..9d1ea46117 100644
--- a/include/char/char.h
+++ b/include/char/char.h
@@ -203,6 +203,35 @@ 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
diff --git a/qemu-char.c b/qemu-char.c
index 505a773330..100f9a968c 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3452,6 +3452,29 @@ 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);