auto import from //depot/cupcake/@135843
diff --git a/toolbox/watchprops.c b/toolbox/watchprops.c
new file mode 100644
index 0000000..d311992
--- /dev/null
+++ b/toolbox/watchprops.c
@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#include <cutils/properties.h>
+
+#include <sys/atomics.h>
+
+#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
+#include <sys/_system_properties.h>
+
+
+extern prop_area *__system_property_area__;
+
+typedef struct pwatch pwatch;
+
+struct pwatch
+{
+ const prop_info *pi;
+ unsigned serial;
+};
+
+static pwatch watchlist[1024];
+
+static void announce(const prop_info *pi)
+{
+ char name[PROP_NAME_MAX];
+ char value[PROP_VALUE_MAX];
+ char *x;
+
+ __system_property_read(pi, name, value);
+
+ for(x = value; *x; x++) {
+ if((*x < 32) || (*x > 127)) *x = '.';
+ }
+
+ fprintf(stderr,"%10d %s = '%s'\n", (int) time(0), name, value);
+}
+
+int watchprops_main(int argc, char *argv[])
+{
+ prop_area *pa = __system_property_area__;
+ unsigned serial = pa->serial;
+ unsigned count = pa->count;
+ unsigned n;
+
+ if(count >= 1024) exit(1);
+
+ for(n = 0; n < count; n++) {
+ watchlist[n].pi = __system_property_find_nth(n);
+ watchlist[n].serial = watchlist[n].pi->serial;
+ }
+
+ for(;;) {
+ do {
+ __futex_wait(&pa->serial, serial, 0);
+ } while(pa->serial == serial);
+
+ while(count < pa->count){
+ watchlist[count].pi = __system_property_find_nth(count);
+ watchlist[count].serial = watchlist[n].pi->serial;
+ announce(watchlist[count].pi);
+ count++;
+ if(count == 1024) exit(1);
+ }
+
+ for(n = 0; n < count; n++){
+ unsigned tmp = watchlist[n].pi->serial;
+ if(watchlist[n].serial != tmp) {
+ announce(watchlist[n].pi);
+ watchlist[n].serial = tmp;
+ }
+ }
+ }
+ return 0;
+}