# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxxx
# Node ID bbcac2aea0e8196cd75a3bf6dbe57bebf8c1e5b2
# Parent dc973fe5633386547ce5bc8fd4cf5f2bb5b55174
[QEMU] Helper functions to interface with the xenstore and read device
information from it.
- detect what types of devices a domain has or whether a domain has a
device of a certain type
- read the content of a variable related to a device, i.e.,
hotplug-status
- subscribe to changes of the hotplug status of a device for not
having to poll the status
Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxx>
---
tools/ioemu/vl.h | 19 ++++++
tools/ioemu/xenstore.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 156 insertions(+)
diff -r dc973fe56333 -r bbcac2aea0e8 tools/ioemu/vl.h
--- a/tools/ioemu/vl.h Fri Oct 27 18:57:02 2006 +0100
+++ b/tools/ioemu/vl.h Fri Oct 27 19:13:51 2006 +0100
@@ -1213,6 +1213,25 @@ void xenstore_write_vncport(int vnc_disp
void xenstore_write_vncport(int vnc_display);
int xenstore_read_vncpasswd(int domid);
+int xenstore_domain_has_devtype(struct xs_handle *handle,
+ const char *devtype);
+char **xenstore_domain_get_devices(struct xs_handle *handle,
+ const char *devtype, unsigned int *num);
+char *xenstore_read_hotplug_status(struct xs_handle *handle,
+ const char *devtype, const char *inst);
+char *xenstore_backend_read_variable(struct xs_handle *,
+ const char *devtype, const char *inst,
+ const char *var);
+int xenstore_subscribe_to_hotplug_status(struct xs_handle *handle,
+ const char *devtype,
+ const char *inst,
+ const char *token);
+int xenstore_unsubscribe_from_hotplug_status(struct xs_handle *handle,
+ const char *devtype,
+ const char *inst,
+ const char *token);
+
+
/* xen_platform.c */
void pci_xen_platform_init(PCIBus *bus);
diff -r dc973fe56333 -r bbcac2aea0e8 tools/ioemu/xenstore.c
--- a/tools/ioemu/xenstore.c Fri Oct 27 18:57:02 2006 +0100
+++ b/tools/ioemu/xenstore.c Fri Oct 27 19:13:51 2006 +0100
@@ -264,3 +264,140 @@ int xenstore_read_vncpasswd(int domid)
return rc;
}
+
+
+/*
+ * get all device instances of a certain type
+ */
+char **xenstore_domain_get_devices(struct xs_handle *handle,
+ const char *devtype, unsigned int *num)
+{
+ char *path;
+ char *buf = NULL;
+ char **e = NULL;
+
+ path = xs_get_domain_path(handle, domid);
+ if (path == NULL)
+ goto out;
+
+ if (pasprintf(&buf, "%s/device/%s", path,devtype) == -1)
+ goto out;
+
+ e = xs_directory(handle, XBT_NULL, buf, num);
+
+ out:
+ free(path);
+ free(buf);
+ return e;
+}
+
+/*
+ * Check whether a domain has devices of the given type
+ */
+int xenstore_domain_has_devtype(struct xs_handle *handle, const char *devtype)
+{
+ int rc = 0;
+ unsigned int num;
+ char **e = xenstore_domain_get_devices(handle, devtype, &num);
+ if (e)
+ rc = 1;
+ free(e);
+ return rc;
+}
+
+/*
+ * Function that creates a path to a variable of an instance of a
+ * certain device
+ */
+static char *get_device_variable_path(const char *devtype, const char *inst,
+ const char *var)
+{
+ char *buf = NULL;
+ if (pasprintf(&buf, "/local/domain/0/backend/%s/%d/%s/%s",
+ devtype,
+ domid,
+ inst,
+ var) == -1) {
+ free(buf);
+ buf = NULL;
+ }
+ return buf;
+}
+
+char *xenstore_backend_read_variable(struct xs_handle *handle,
+ const char *devtype, const char *inst,
+ const char *var)
+{
+ char *value = NULL;
+ char *buf = NULL;
+ unsigned int len;
+
+ buf = get_device_variable_path(devtype, inst, var);
+ if (NULL == buf)
+ goto out;
+
+ value = xs_read(handle, XBT_NULL, buf, &len);
+
+ free(buf);
+
+out:
+ return value;
+}
+
+/*
+ Read the hotplug status variable from the backend given the type
+ of device and its instance.
+*/
+char *xenstore_read_hotplug_status(struct xs_handle *handle,
+ const char *devtype, const char *inst)
+{
+ return xenstore_backend_read_variable(handle, devtype, inst,
+ "hotplug-status");
+}
+
+/*
+ Subscribe to the hotplug status of a device given the type of device and
+ its instance.
+ In case an error occurrs, a negative number is returned.
+ */
+int xenstore_subscribe_to_hotplug_status(struct xs_handle *handle,
+ const char *devtype,
+ const char *inst,
+ const char *token)
+{
+ int rc = 0;
+ char *path = get_device_variable_path(devtype, inst, "hotplug-status");
+
+ if (path == NULL)
+ return -1;
+
+ if (0 == xs_watch(handle, path, token))
+ rc = -2;
+
+ free(path);
+
+ return rc;
+}
+
+/*
+ * Unsubscribe from a subscription to the status of a hotplug variable of
+ * a device.
+ */
+int xenstore_unsubscribe_from_hotplug_status(struct xs_handle *handle,
+ const char *devtype,
+ const char *inst,
+ const char *token)
+{
+ int rc = 0;
+ char *path;
+ path = get_device_variable_path(devtype, inst, "hotplug-status");
+ if (path == NULL)
+ return -1;
+
+ if (0 == xs_unwatch(handle, path, token))
+ rc = -2;
+
+ free(path);
+
+ return rc;
+}
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