toolbox ps: replace strcpy with snprintf.

Change-Id: I0fdf9a8d5ab15bcff06cca3f3e7024ab76b219d9
diff --git a/toolbox/ps.c b/toolbox/ps.c
index 3b3c8a1..c129110 100644
--- a/toolbox/ps.c
+++ b/toolbox/ps.c
@@ -151,7 +151,7 @@
     if (pw == 0 || (display_flags & SHOW_NUMERIC_UID)) {
         snprintf(user, sizeof(user), "%d", (int)stats.st_uid);
     } else {
-        strcpy(user, pw->pw_name);
+        snprintf(user, sizeof(user), "%s", pw->pw_name);
     }
 
     if (ppid_filter != 0 && ppid != ppid_filter) {