[src/trunk]: src/usr.bin/make make: prevent memory leaks from buffers

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

details:   https://anonhg.NetBSD.org/src/rev/5f1856a00a2c
branches:  trunk
changeset: 1027671:5f1856a00a2c
user:      rillig <rillig%NetBSD.org@localhost>
date:      Wed Dec 15 09:29:55 2021 +0000

description:
make: prevent memory leaks from buffers

The warning about unused function results would have prevented the
memory leak that was fixed in cond.c 1.303 from 2021-12-13.

diffstat:

 usr.bin/make/buf.c  |  7 ++++---
 usr.bin/make/buf.h  |  8 ++++----
 usr.bin/make/make.h |  8 +++++++-
 3 files changed, 15 insertions(+), 8 deletions(-)

diffs (79 lines):

diff -r 0551aa88ebb1 -r 5f1856a00a2c usr.bin/make/buf.c
--- a/usr.bin/make/buf.c        Wed Dec 15 09:19:34 2021 +0000
+++ b/usr.bin/make/buf.c        Wed Dec 15 09:29:55 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: buf.c,v 1.53 2021/11/28 22:48:06 rillig Exp $  */
+/*     $NetBSD: buf.c,v 1.54 2021/12/15 09:29:55 rillig Exp $  */
 
 /*
  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -75,7 +75,7 @@
 #include "make.h"
 
 /*     "@(#)buf.c      8.1 (Berkeley) 6/6/93"  */
-MAKE_RCSID("$NetBSD: buf.c,v 1.53 2021/11/28 22:48:06 rillig Exp $");
+MAKE_RCSID("$NetBSD: buf.c,v 1.54 2021/12/15 09:29:55 rillig Exp $");
 
 /* Make space in the buffer for adding at least 16 more bytes. */
 void
@@ -214,8 +214,9 @@
        if (buf->cap - buf->len >= BUF_COMPACT_LIMIT) {
                /* We trust realloc to be smart */
                char *data = bmake_realloc(buf->data, buf->len + 1);
+               buf->data = NULL;
                data[buf->len] = '\0';  /* XXX: unnecessary */
-               Buf_DoneData(buf);
+               Buf_Done(buf);
                return data;
        }
 #endif
diff -r 0551aa88ebb1 -r 5f1856a00a2c usr.bin/make/buf.h
--- a/usr.bin/make/buf.h        Wed Dec 15 09:19:34 2021 +0000
+++ b/usr.bin/make/buf.h        Wed Dec 15 09:29:55 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: buf.h,v 1.44 2021/11/28 22:48:06 rillig Exp $  */
+/*     $NetBSD: buf.h,v 1.45 2021/12/15 09:29:55 rillig Exp $  */
 
 /*
  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -101,7 +101,7 @@
        end[1] = '\0';
 }
 
-MAKE_INLINE bool
+MAKE_INLINE bool MAKE_ATTR_USE
 Buf_EndsWith(const Buffer *buf, char ch)
 {
        return buf->len > 0 && buf->data[buf->len - 1] == ch;
@@ -116,7 +116,7 @@
 void Buf_Init(Buffer *);
 void Buf_InitSize(Buffer *, size_t);
 void Buf_Done(Buffer *);
-char *Buf_DoneData(Buffer *);
-char *Buf_DoneDataCompact(Buffer *);
+char *Buf_DoneData(Buffer *) MAKE_ATTR_USE;
+char *Buf_DoneDataCompact(Buffer *) MAKE_ATTR_USE;
 
 #endif /* MAKE_BUF_H */
diff -r 0551aa88ebb1 -r 5f1856a00a2c usr.bin/make/make.h
--- a/usr.bin/make/make.h       Wed Dec 15 09:19:34 2021 +0000
+++ b/usr.bin/make/make.h       Wed Dec 15 09:29:55 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: make.h,v 1.272 2021/12/13 22:26:21 rillig Exp $        */
+/*     $NetBSD: make.h,v 1.273 2021/12/15 09:29:55 rillig Exp $        */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -130,6 +130,12 @@
 #define MAKE_ATTR_PRINTFLIKE(fmtarg, firstvararg)      /* delete */
 #endif
 
+#if MAKE_GNUC_PREREQ(4, 0)
+#define MAKE_ATTR_USE __attribute__((__warn_unused_result__))
+#else
+#define MAKE_ATTR_USE /* delete */
+#endif
+
 #define MAKE_INLINE static inline MAKE_ATTR_UNUSED
 
 /* MAKE_STATIC marks a function that may or may not be inlined. */