Add support for getprop -Z

Add support for a -Z option to getprop that will either print the
SELabel of a given property if one is provided or print all properties
that have been set along with their SELabel.

Also, correct a memory leak when freeing TT.nv.

diff --git a/toys/android/getprop.c b/toys/android/getprop.c
index 09bb0f0..cce53a6 100644 (file)
--- a/toys/android/getprop.c
+++ b/toys/android/getprop.c
@@ -2,7 +2,7 @@
  *
  * Copyright 2015 The Android Open Source Project
 
-USE_GETPROP(NEWTOY(getprop, ">2", TOYFLAG_USR|TOYFLAG_SBIN))
+USE_GETPROP(NEWTOY(getprop, ">2Z", TOYFLAG_USR|TOYFLAG_SBIN))
 
 config GETPROP
   bool "getprop"
@@ -19,30 +19,83 @@ config GETPROP
 
 #include <cutils/properties.h>
 
+#include <selinux/android.h>
+#include <selinux/label.h>
+#include <selinux/selinux.h>
+
 GLOBALS(
   size_t size;
   char **nv; // name/value pairs: even=name, odd=value
+  struct selabel_handle *handle;
 )
 
+static char *get_property_context(char *property)
+{
+  char *context = NULL;
+
+  if (selabel_lookup(TT.handle, &context, property, 1)) {
+    perror_exit("unable to lookup label for \"%s\"", property);
+  }
+  return context;
+}
+
 static void add_property(char *name, char *value, void *unused)
 {
   if (!(TT.size&31)) TT.nv = xrealloc(TT.nv, (TT.size+32)*2*sizeof(char *));
 
   TT.nv[2*TT.size] = xstrdup(name);
-  TT.nv[1+2*TT.size++] = xstrdup(value);
+  if (toys.optflags & FLAG_Z) {
+    TT.nv[1+2*TT.size++] = get_property_context(name);
+  } else {
+    TT.nv[1+2*TT.size++] = xstrdup(value);
+  }
+}
+
+// Needed to supress extraneous "Loaded property_contexts from" message
+int selinux_log_callback(int type, const char *fmt, ...) {
+  va_list ap;
+
+  if (type == SELINUX_INFO) return 0;
+  va_start(ap, fmt);
+  verror_msg(fmt, 0, ap);
+  va_end(ap);
+  return 0;
 }
 
 void getprop_main(void)
 {
+  if (toys.optflags & FLAG_Z) {
+    union selinux_callback cb;
+
+    cb.func_log = selinux_log_callback;
+    selinux_set_callback(SELINUX_CB_LOG, cb);
+    TT.handle = selinux_android_prop_context_handle();
+    if (!TT.handle) error_exit("unable to get selinux property context handle");
+  }
+
   if (*toys.optargs) {
-    property_get(*toys.optargs, toybuf, toys.optargs[1] ? toys.optargs[1] : "");
-    puts(toybuf);
+    if (toys.optflags & FLAG_Z) {
+      char *context = get_property_context(*toys.optargs);
+
+      puts(context);
+      if (CFG_TOYBOX_FREE) free(context);
+    } else {
+      property_get(*toys.optargs, toybuf, toys.optargs[1] ? toys.optargs[1] : "");
+      puts(toybuf);
+    }
   } else {
     size_t i;
 
     if (property_list((void *)add_property, 0)) error_exit("property_list");
     qsort(TT.nv, TT.size, 2*sizeof(char *), qstrcmp);
     for (i = 0; i<TT.size; i++) printf("[%s]: [%s]\n", TT.nv[i*2],TT.nv[1+i*2]);
-    if (CFG_TOYBOX_FREE) free(TT.nv);
+    if (CFG_TOYBOX_FREE) {
+      for (i = 0; i<TT.size; i++) {
+        free(TT.nv[i*2]);
+        free(TT.nv[1+i*2]);
+      }
+      free(TT.nv);
+    }
   }
+  if (CFG_TOYBOX_FREE && (toys.optflags & FLAG_Z)) selabel_close(TT.handle);
 }