who: fix only-theoretical overflow

Change stzncpy’s implementation to match its comment, in the case
where SRC + LEN would overflow.  This case never happens in coreutils.
* src/system.h (stzncpy): Work even if SRC + LEN would overflow.

diff --git a/src/system.h b/src/system.h
index db1a6773b91249404056690cf9ec08e0164d4ed2..2d9c47f48b073386033f813db364c38a9539cb54 100644 (file)
--- a/src/system.h
+++ b/src/system.h
@@ -781,8 +781,8 @@ write_error (void)
 static inline char *
 stzncpy (char *restrict dest, char const *restrict src, size_t len)
 {
-  char const *src_end = src + len;
-  while (src < src_end && *src)
+  size_t i;
+  for (i = 0; i < len && *src; i++)
     *dest++ = *src++;
   *dest = 0;
   return dest;