[src/trunk]: src/usr.bin/make make(1): make InitVarMake simpler and document ...

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

details:   https://anonhg.NetBSD.org/src/rev/38b4be9a4508
branches:  trunk
changeset: 977585:38b4be9a4508
user:      rillig <rillig%NetBSD.org@localhost>
date:      Tue Oct 27 18:12:15 2020 +0000

description:
make(1): make InitVarMake simpler and document its intention

diffstat:

 usr.bin/make/main.c |  43 +++++++++++++++++++------------------------
 1 files changed, 19 insertions(+), 24 deletions(-)

diffs (75 lines):

diff -r 6b45e34dc5da -r 38b4be9a4508 usr.bin/make/main.c
--- a/usr.bin/make/main.c       Tue Oct 27 17:36:17 2020 +0000
+++ b/usr.bin/make/main.c       Tue Oct 27 18:12:15 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: main.c,v 1.405 2020/10/27 17:36:17 rillig Exp $        */
+/*     $NetBSD: main.c,v 1.406 2020/10/27 18:12:15 rillig Exp $        */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -118,7 +118,7 @@
 #include "trace.h"
 
 /*     "@(#)main.c     8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: main.c,v 1.405 2020/10/27 17:36:17 rillig Exp $");
+MAKE_RCSID("$NetBSD: main.c,v 1.406 2020/10/27 18:12:15 rillig Exp $");
 #if defined(MAKE_NATIVE) && !defined(lint)
 __COPYRIGHT("@(#) Copyright (c) 1988, 1989, 1990, 1993 "
            "The Regents of the University of California.  "
@@ -1095,31 +1095,26 @@
        opts.create = Lst_New();
 }
 
+/* Initialize MAKE and .MAKE to the path of the executable, so that it can be
+ * found by execvp(3) and the shells, even after a chdir.
+ *
+ * If it's a relative path and contains a '/', resolve it to an absolute path.
+ * Otherwise keep it as is, assuming it will be found in the PATH. */
 static void
-InitVarMake(char **argv)
+InitVarMake(const char *argv0)
 {
-       char mdpath[MAXPATHLEN];
-       const char *p1;
+       const char *make = argv0;
 
-       if (argv[0][0] == '/' || strchr(argv[0], '/') == NULL) {
-               /*
-                * Leave alone if it is an absolute path, or if it does
-                * not contain a '/' in which case we need to find it in
-                * the path, like execvp(3) and the shells do.
-                */
-               p1 = argv[0];
-       } else {
-               struct stat sb;
-               /*
-                * A relative path, canonicalize it.
-                */
-               p1 = cached_realpath(argv[0], mdpath);
-               if (!p1 || *p1 != '/' || stat(p1, &sb) < 0) {
-                       p1 = argv[0];           /* realpath failed */
-               }
+       if (argv0[0] != '/' && strchr(argv0, '/') != NULL) {
+               char pathbuf[MAXPATHLEN];
+               const char *abs = cached_realpath(argv0, pathbuf);
+               struct stat st;
+               if (abs != NULL && abs[0] == '/' && stat(make, &st) == 0)
+                       make = abs;
        }
-       Var_Set("MAKE", p1, VAR_GLOBAL);
-       Var_Set(".MAKE", p1, VAR_GLOBAL);
+
+       Var_Set("MAKE", make, VAR_GLOBAL);
+       Var_Set(".MAKE", make, VAR_GLOBAL);
 }
 
 static void
@@ -1370,7 +1365,7 @@
         *      MFLAGS also gets initialized empty, for compatibility.
         */
        Parse_Init();
-       InitVarMake(argv);
+       InitVarMake(argv[0]);
        Var_Set(MAKEFLAGS, "", VAR_GLOBAL);
        Var_Set(MAKEOVERRIDES, "", VAR_GLOBAL);
        Var_Set("MFLAGS", "", VAR_GLOBAL);