[src/trunk]: src/usr.bin/make make(1): use snprintf instead of strncpy

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/40b37e5be51f
branches:  trunk
changeset: 936589:40b37e5be51f
user:      rillig <rillig%NetBSD.org@localhost>
date:      Fri Jul 31 16:26:16 2020 +0000

description:
make(1): use snprintf instead of strncpy

strncpy is not suited for string processing, despite its name.

Even though the previous code used the correct code pattern for strncpy,
it still wasted cycles since strncpy always fills the whole target
buffer. That's not needed.

diffstat:

 usr.bin/make/arch.c |  12 +++++-------
 1 files changed, 5 insertions(+), 7 deletions(-)

diffs (46 lines):

diff -r 8fdd03004821 -r 40b37e5be51f usr.bin/make/arch.c
--- a/usr.bin/make/arch.c       Fri Jul 31 15:16:05 2020 +0000
+++ b/usr.bin/make/arch.c       Fri Jul 31 16:26:16 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: arch.c,v 1.77 2020/07/28 16:42:22 rillig Exp $ */
+/*     $NetBSD: arch.c,v 1.78 2020/07/31 16:26:16 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -69,14 +69,14 @@
  */
 
 #ifndef MAKE_NATIVE
-static char rcsid[] = "$NetBSD: arch.c,v 1.77 2020/07/28 16:42:22 rillig Exp $";
+static char rcsid[] = "$NetBSD: arch.c,v 1.78 2020/07/31 16:26:16 rillig Exp $";
 #else
 #include <sys/cdefs.h>
 #ifndef lint
 #if 0
 static char sccsid[] = "@(#)arch.c     8.2 (Berkeley) 1/2/94";
 #else
-__RCSID("$NetBSD: arch.c,v 1.77 2020/07/28 16:42:22 rillig Exp $");
+__RCSID("$NetBSD: arch.c,v 1.78 2020/07/31 16:26:16 rillig Exp $");
 #endif
 #endif /* not lint */
 #endif
@@ -562,8 +562,7 @@
 
            if (len > AR_MAX_NAME_LEN) {
                len = AR_MAX_NAME_LEN;
-               strncpy(copy, member, AR_MAX_NAME_LEN);
-               copy[AR_MAX_NAME_LEN] = '\0';
+               snprintf(copy, sizeof copy, "%s", member);
            }
            if ((he = Hash_FindEntry(&ar->members, copy)) != NULL)
                return (struct ar_hdr *)Hash_GetValue(he);
@@ -814,8 +813,7 @@
        fprintf(debug_file, "Replaced %s with %s\n", name, &ar->fnametab[entry]);
     }
 
-    (void)strncpy(name, &ar->fnametab[entry], MAXPATHLEN);
-    name[MAXPATHLEN] = '\0';
+    snprintf(name, MAXPATHLEN + 1, "%s", &ar->fnametab[entry]);
     return 1;
 }
 #endif