ueventd: support by-name symlinks for virtual block devices
This patch makes ueventd create by-name symlinks for virtual block
devices when Android is running as a Xen guest OS.
The symlinks will be created under /dev/block/vbd/. For example:
/dev/block/vbd/768/by-name/
Change-Id: Id45da560d13f641d7c8419511c154de9ae8a4ec9
Test: manual
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
diff --git a/init/devices.cpp b/init/devices.cpp
index bd11f5f..405f92e 100644
--- a/init/devices.cpp
+++ b/init/devices.cpp
@@ -390,6 +390,34 @@
return 0;
}
+/* Given a path that may start with a virtual block device, populate
+ * the supplied buffer with the virtual block device ID and return 0.
+ * If it doesn't start with a virtual block device, or there is some
+ * error, return -1 */
+static int find_vbd_device_prefix(const char *path, char *buf, ssize_t buf_sz)
+{
+ const char *start, *end;
+
+ /* Beginning of the prefix is the initial "vbd-" after "/devices/" */
+ if (strncmp(path, "/devices/vbd-", 13))
+ return -1;
+
+ /* End of the prefix is one path '/' later, capturing the
+ virtual block device ID. Example: 768 */
+ start = path + 13;
+ end = strchr(start, '/');
+ if (!end)
+ return -1;
+
+ /* Make sure we have enough room for the string plus null terminator */
+ if (end - start + 1 > buf_sz)
+ return -1;
+
+ strncpy(buf, start, end - start);
+ buf[end - start] = '\0';
+ return 0;
+}
+
static void parse_event(const char *msg, struct uevent *uevent)
{
uevent->action = "";
@@ -516,6 +544,9 @@
} else if (!find_pci_device_prefix(uevent->path, buf, sizeof(buf))) {
device = buf;
type = "pci";
+ } else if (!find_vbd_device_prefix(uevent->path, buf, sizeof(buf))) {
+ device = buf;
+ type = "vbd";
} else {
return NULL;
}