make(1): remove unreached code from bmake_strndup

The "at most" branch was never taken since all call sites in var.c only
ever need a substring, and the target buffer is not limited.  Therefore
rename the function and make it simpler.

It's ok that bmake_strldup is defined as estrndup in case of USE_EMALLOC
since that function's implementation is compatible to the "copy
exactly", it just contains some extra null checks that will never match
since the variable values cannot (well, or should not) contain null
bytes.  Theoretically they can, but the behavior then depends on the
exact implementation and is unreliable, therefore nobody does this.
After all, Makefiles are used for text processing, not for binary data.
This commit is contained in:
rillig 2020-08-20 06:35:14 +00:00
parent 58e1cf785c
commit 0cbd5c0e4f
3 changed files with 15 additions and 25 deletions

View File

@ -1,4 +1,4 @@
/* $NetBSD: make_malloc.c,v 1.14 2020/08/12 18:47:21 rillig Exp $ */
/* $NetBSD: make_malloc.c,v 1.15 2020/08/20 06:35:14 rillig Exp $ */
/*-
* Copyright (c) 2009 The NetBSD Foundation, Inc.
@ -28,7 +28,7 @@
#ifdef MAKE_NATIVE
#include <sys/cdefs.h>
__RCSID("$NetBSD: make_malloc.c,v 1.14 2020/08/12 18:47:21 rillig Exp $");
__RCSID("$NetBSD: make_malloc.c,v 1.15 2020/08/20 06:35:14 rillig Exp $");
#endif
#include <stdio.h>
@ -82,23 +82,13 @@ bmake_strdup(const char *str)
return memcpy(p, str, len);
}
/*
* bmake_strndup --
* strndup, but die on error.
*/
/* Allocate a string starting from str with exactly len characters. */
char *
bmake_strndup(const char *str, size_t max_len)
bmake_strldup(const char *str, size_t len)
{
size_t len;
char *p;
for (len = 0; len < max_len; len++)
if (str[len] == '\0')
break;
p = bmake_malloc(len + 1);
char *p = bmake_malloc(len + 1);
memcpy(p, str, len);
p[len] = '\0';
return p;
}

View File

@ -1,4 +1,4 @@
/* $NetBSD: make_malloc.h,v 1.6 2020/08/01 14:47:49 rillig Exp $ */
/* $NetBSD: make_malloc.h,v 1.7 2020/08/20 06:35:14 rillig Exp $ */
/*-
* Copyright (c) 2009 The NetBSD Foundation, Inc.
@ -30,13 +30,13 @@
void *bmake_malloc(size_t);
void *bmake_realloc(void *, size_t);
char *bmake_strdup(const char *);
char *bmake_strndup(const char *, size_t);
char *bmake_strldup(const char *, size_t);
#else
#include <util.h>
#define bmake_malloc(x) emalloc(x)
#define bmake_realloc(x,y) erealloc(x,y)
#define bmake_strdup(x) estrdup(x)
#define bmake_strndup(x,y) estrndup(x,y)
#define bmake_strldup(x,y) estrndup(x,y)
#endif
/* Thin wrapper around free(3) to avoid the extra function call in case

View File

@ -1,4 +1,4 @@
/* $NetBSD: var.c,v 1.449 2020/08/13 04:12:13 rillig Exp $ */
/* $NetBSD: var.c,v 1.450 2020/08/20 06:35:14 rillig Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1993
@ -69,14 +69,14 @@
*/
#ifndef MAKE_NATIVE
static char rcsid[] = "$NetBSD: var.c,v 1.449 2020/08/13 04:12:13 rillig Exp $";
static char rcsid[] = "$NetBSD: var.c,v 1.450 2020/08/20 06:35:14 rillig Exp $";
#else
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)var.c 8.3 (Berkeley) 3/19/94";
#else
__RCSID("$NetBSD: var.c,v 1.449 2020/08/13 04:12:13 rillig Exp $");
__RCSID("$NetBSD: var.c,v 1.450 2020/08/20 06:35:14 rillig Exp $");
#endif
#endif /* not lint */
#endif
@ -2280,7 +2280,7 @@ ApplyModifier_Match(const char **pp, ApplyModifiersState *st)
* Either Var_Subst or ModifyWords will need a
* nul-terminated string soon, so construct one now.
*/
pattern = bmake_strndup(mod + 1, (size_t)(endpat - (mod + 1)));
pattern = bmake_strldup(mod + 1, (size_t)(endpat - (mod + 1)));
}
if (needSubst) {
@ -2894,7 +2894,7 @@ ApplyModifier_Remember(const char **pp, ApplyModifiersState *st)
if (mod[1] == '=') {
size_t n = strcspn(mod + 2, ":)}");
char *name = bmake_strndup(mod + 2, n);
char *name = bmake_strldup(mod + 2, n);
Var_Set(name, st->val, st->ctxt);
free(name);
*pp = mod + 2 + n;
@ -3510,7 +3510,7 @@ Var_Parse(const char * const str, GNode *ctxt, VarEvalFlags eflags,
*/
*lengthPtr = (int)(size_t)(tstr - str) + 1;
if (dynamic) {
char *pstr = bmake_strndup(str, (size_t)*lengthPtr);
char *pstr = bmake_strldup(str, (size_t)*lengthPtr);
*freePtr = pstr;
Buf_Destroy(&namebuf, TRUE);
return pstr;
@ -3605,7 +3605,7 @@ Var_Parse(const char * const str, GNode *ctxt, VarEvalFlags eflags,
*freePtr = NULL;
}
if (dynamic) {
nstr = bmake_strndup(str, (size_t)*lengthPtr);
nstr = bmake_strldup(str, (size_t)*lengthPtr);
*freePtr = nstr;
} else {
nstr = (eflags & VARE_UNDEFERR) ? var_Error : varNoError;