util: modernize get_parent_of_pid() a bit

diff --git a/src/util.c b/src/util.c
index 75ad56fecf2f3e45d0bd193b59bde6746b74e365..39c9db72fcc93271fb33efd7412e4548ce423318 100644 (file)
--- a/src/util.c
+++ b/src/util.c
@@ -456,11 +456,11 @@ int get_parent_of_pid(pid_t pid, pid_t *_ppid) {
         char fn[PATH_MAX], line[LINE_MAX], *p;
         long unsigned ppid;
 
-        assert(pid >= 0);
+        assert(pid > 0);
         assert(_ppid);
 
         assert_se(snprintf(fn, sizeof(fn)-1, "/proc/%lu/stat", (unsigned long) pid) < (int) (sizeof(fn)-1));
-        fn[sizeof(fn)-1] = 0;
+        char_array_0(fn);
 
         if (!(f = fopen(fn, "r")))
                 return -errno;