Add 'run-as' command implementation as set-uid program.

Typical usage is 'run-as <package-name> <command>' to run <command>
in the data directory, and the user id, of <package-name> if, and only
if <package-name> is the name of an installed and debuggable application.

This relies on the /data/system/packages.list file generated by the
PackageManager service.

BEWARE: This is intended to be available on production devices !
diff --git a/run-as/package.h b/run-as/package.h
new file mode 100644
index 0000000..852af06
--- /dev/null
+++ b/run-as/package.h
@@ -0,0 +1,41 @@
+/*
+**
+** Copyright 2010, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+#ifndef RUN_AS_PACKAGE_H
+#define RUN_AS_PACKAGE_H
+
+#include <limits.h>
+#include <sys/types.h>
+
+typedef enum {
+    PACKAGE_IS_DEBUGGABLE = 0,
+    PACKAGE_IS_NOT_DEBUGGABLE,
+    PACKAGE_IS_UNKNOWN,
+} PackageStatus;
+
+typedef struct {
+    uid_t  uid;
+    char   isDebuggable;
+    char   dataDir[PATH_MAX];
+} PackageInfo;
+
+/* see documentation in package.c for these functiosn */
+
+extern int  get_package_info(const char* packageName, PackageInfo*  info);
+
+extern int  check_data_path(const char* dataDir, uid_t uid);
+
+#endif /* RUN_AS_PACKAGE_H */