adb: handle adbd auth in recovery mode

If /data/misc/adb/adb_keys exists, copy it to /adb_keys, set property
for secure adb, and restart the adbd daemon.

Change-Id: I2f826d4c1f6a49cb0959c9cd1a803cb10ec4e408

etc/init.rc

@@ -52,11 +52,7 @@ service recovery /sbin/recovery
 service adbd /sbin/adbd recovery
     disabled
 
-# Always start adbd on userdebug and eng builds
-on property:ro.debuggable=1
-    write /sys/class/android_usb/android0/enable 1
-    start adbd
-    setprop service.adb.root 1
+# Recovery will start adb once it has checked the keys
 
 # Restart adbd so it can run as root
 on property:service.adb.root=1

recovery.c

@@ -751,6 +751,39 @@ print_property(const char *key, const char *name, void *cookie) {
     printf("%s=%s\n", key, name);
 }
 
+static void
+setup_adbd() {
+    struct stat f;
+    static char *key_src = "/data/misc/adb/adb_keys";
+    static char *key_dest = "/adb_keys";
+
+    // Mount /data and copy adb_keys to root if it exists
+    ensure_path_mounted("/data");
+    if (stat(key_src, &f) == 0) {
+        FILE *file_src = fopen(key_src, "r");
+        if (file_src == NULL) {
+            LOGE("Can't open %s\n", key_src);
+        } else {
+            FILE *file_dest = fopen(key_dest, "w");
+            if (file_dest == NULL) {
+                LOGE("Can't open %s\n", key_dest);
+            } else {
+                char buf[4096];
+                while (fgets(buf, sizeof(buf), file_src)) fputs(buf, file_dest);
+                check_and_fclose(file_dest, key_dest);
+
+                // Enable secure adbd
+                property_set("ro.adb.secure", "1");
+            }
+            check_and_fclose(file_src, key_src);
+        }
+    }
+    ensure_path_unmounted("/data");
+
+    // Trigger (re)start of adb daemon
+    property_set("service.adb.root", "1");
+}
+
 int
 main(int argc, char **argv) {
 
@@ -912,6 +945,8 @@ main(int argc, char **argv) {
         }
     }
 
+    setup_adbd();
+
     if (status != INSTALL_SUCCESS && !is_user_initiated_recovery) {
         ui_set_show_text(1);
         ui_set_background(BACKGROUND_ICON_ERROR);