Create log-dirty shared memory between stubdom-dm and xc_save.
Process logdirty events when working as a stubdom-dm.

Signed-off-by: Yosuke Iwamatsu <y-iwamatsu@ab.jp.nec.com>

diff --git a/xenstore.c b/xenstore.c
index d064df1..3a3a0bd 100644
--- a/xenstore.c
+++ b/xenstore.c
@@ -596,10 +596,6 @@ extern int vga_ram_size, bios_size;
 
 void xenstore_process_logdirty_event(void)
 {
-#ifdef CONFIG_STUBDOM
-    /* XXX we just can't use shm. */
-    return;
-#else
     char *act;
     static char *active_path = NULL;
     static char *next_active_path = NULL;
@@ -638,6 +634,25 @@ void xenstore_process_logdirty_event(void)
                                 / HOST_LONG_BITS); /* longs */
         logdirty_bitmap_size *= sizeof (unsigned long); /* bytes */
 
+#ifdef CONFIG_STUBDOM
+        /* Initialize logdirty bitmap */
+        if (pasprintf(&path, 
+                      "/local/domain/0/device-model/%u/logdirty", 
+                      domid) == -1) {
+            fprintf(logfile, "Log-dirty: out of memory\n");
+            exit(1);
+        }
+
+        seg = init_logdirty_bitmap(path, logdirty_bitmap_size, 0);
+        if (seg == NULL) {
+            fprintf(logfile, "Log-dirty: failed to allocate bitmap\n");
+            exit(1);
+        }
+        free(path);
+
+        /* Write the size of bitmap into the first 32 bits */
+        *(uint32_t *)seg = logdirty_bitmap_size;
+#else
         /* Map the shared-memory segment */
         fprintf(logfile, "%s: key=%16.16llx size=%lu\n", __FUNCTION__,
                 (unsigned long long)key, logdirty_bitmap_size);
@@ -666,6 +681,7 @@ void xenstore_process_logdirty_event(void)
             seg = NULL;
             return;
         }
+#endif
 
         /* Remember the paths for the next-active and active entries */
         if (pasprintf(&active_path, 
@@ -702,7 +718,6 @@ void xenstore_process_logdirty_event(void)
     /* Ack that we've switched */
     xs_write(xsh, XBT_NULL, active_path, act, len);
     free(act);
-#endif
 }