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.

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);
 }