[src/trunk]: src/usr.bin/make make(1): handle special case of a list containi...

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

details:   https://anonhg.NetBSD.org/src/rev/66b6ec588618
branches:  trunk
changeset: 942990:66b6ec588618
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Aug 23 10:53:27 2020 +0000

description:
make(1): handle special case of a list containing null pointers

GNode.commands is the only place in make where a list can contain null
pointers.  That's unexpected, and memory management in CompatRunCommand
looks suspicous enough to warrant extensive documentation.

diffstat:

 usr.bin/make/compat.c |  12 +++++++-----
 usr.bin/make/lst.c    |  20 ++++++++++++++++----
 usr.bin/make/lst.h    |   5 +++--
 3 files changed, 26 insertions(+), 11 deletions(-)

diffs (113 lines):

diff -r f61c6ddc7ad3 -r 66b6ec588618 usr.bin/make/compat.c
--- a/usr.bin/make/compat.c     Sun Aug 23 10:27:22 2020 +0000
+++ b/usr.bin/make/compat.c     Sun Aug 23 10:53:27 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: compat.c,v 1.126 2020/08/22 21:42:38 rillig Exp $      */
+/*     $NetBSD: compat.c,v 1.127 2020/08/23 10:53:27 rillig Exp $      */
 
 /*
  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -70,14 +70,14 @@
  */
 
 #ifndef MAKE_NATIVE
-static char rcsid[] = "$NetBSD: compat.c,v 1.126 2020/08/22 21:42:38 rillig Exp $";
+static char rcsid[] = "$NetBSD: compat.c,v 1.127 2020/08/23 10:53:27 rillig Exp $";
 #else
 #include <sys/cdefs.h>
 #ifndef lint
 #if 0
 static char sccsid[] = "@(#)compat.c   8.2 (Berkeley) 3/19/94";
 #else
-__RCSID("$NetBSD: compat.c,v 1.126 2020/08/22 21:42:38 rillig Exp $");
+__RCSID("$NetBSD: compat.c,v 1.127 2020/08/23 10:53:27 rillig Exp $");
 #endif
 #endif /* not lint */
 #endif
@@ -247,7 +247,7 @@
        return 0;
     }
     cmd = cmdStart;
-    Lst_ReplaceS(cmdNode, cmdStart);
+    LstNode_SetS(cmdNode, cmdStart);
 
     if ((gn->type & OP_SAVE_CMDS) && (gn != ENDNode)) {
         assert(ENDNode != NULL);
@@ -394,7 +394,9 @@
     free(mav);
     free(bp);
 
-    Lst_ReplaceS(cmdNode, NULL);
+    /* XXX: Memory management looks suspicious here. */
+    /* XXX: Setting a list item to NULL is unexpected. */
+    LstNode_SetNullS(cmdNode);
 
 #ifdef USE_META
     if (useMeta) {
diff -r f61c6ddc7ad3 -r 66b6ec588618 usr.bin/make/lst.c
--- a/usr.bin/make/lst.c        Sun Aug 23 10:27:22 2020 +0000
+++ b/usr.bin/make/lst.c        Sun Aug 23 10:53:27 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: lst.c,v 1.36 2020/08/22 23:06:51 rillig Exp $ */
+/* $NetBSD: lst.c,v 1.37 2020/08/23 10:53:27 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -37,11 +37,11 @@
 #include "make.h"
 
 #ifndef MAKE_NATIVE
-static char rcsid[] = "$NetBSD: lst.c,v 1.36 2020/08/22 23:06:51 rillig Exp $";
+static char rcsid[] = "$NetBSD: lst.c,v 1.37 2020/08/23 10:53:27 rillig Exp $";
 #else
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: lst.c,v 1.36 2020/08/22 23:06:51 rillig Exp $");
+__RCSID("$NetBSD: lst.c,v 1.37 2020/08/23 10:53:27 rillig Exp $");
 #endif /* not lint */
 #endif
 
@@ -302,11 +302,23 @@
 
 /* Replace the datum in the given node with the new datum. */
 void
-Lst_ReplaceS(LstNode node, void *datum)
+LstNode_SetS(LstNode node, void *datum)
 {
+    assert(LstNodeIsValid(node));
+    assert(datum != NULL);
+
     node->datum = datum;
 }
 
+/* Replace the datum in the given node to NULL. */
+void
+LstNode_SetNullS(LstNode node)
+{
+    assert(LstNodeIsValid(node));
+
+    node->datum = NULL;
+}
+
 
 /*
  * Node-specific functions
diff -r f61c6ddc7ad3 -r 66b6ec588618 usr.bin/make/lst.h
--- a/usr.bin/make/lst.h        Sun Aug 23 10:27:22 2020 +0000
+++ b/usr.bin/make/lst.h        Sun Aug 23 10:53:27 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: lst.h,v 1.38 2020/08/22 22:57:53 rillig Exp $  */
+/*     $NetBSD: lst.h,v 1.39 2020/08/23 10:53:27 rillig Exp $  */
 
 /*
  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -120,7 +120,8 @@
 /* Remove an element */
 void           Lst_RemoveS(Lst, LstNode);
 /* Replace a node with a new value */
-void           Lst_ReplaceS(LstNode, void *);
+void           LstNode_SetS(LstNode node, void *datum);
+void           LstNode_SetNullS(LstNode node);
 void           Lst_PrependAllS(Lst, Lst);
 void           Lst_AppendAllS(Lst, Lst);
 void           Lst_MoveAllS(Lst, Lst);