test16.c

来自「debug source code under unix platform.」· C语言 代码 · 共 62 行

/*
 * mpatrol
 * A library for controlling and tracing dynamic memory allocations.
 * Copyright (C) 1997-2002 Graeme S. Roy <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307, USA.
 */


/*
 * Duplicates a string using alloca() and then returns the address
 * of the allocation.  This is illegal since the memory allocated
 * by alloca() will be freed when the function returns.  The call
 * to memcpy() will then corrupt free memory and the call to free()
 * will attempt to free an invalid pointer.
 */


#include "mpatrol.h"
#include <stdio.h>


char *f(size_t l)
{
    return (char *) alloca(l);
}


char *g(char *s)
{
    char *t;
    size_t l;

    l = strlen(s) + 1;
    if (t = f(l))
        memcpy(t, s, l);
    return t;
}


int main(void)
{
    char *s;

    s = g("test");
    free(s);
    return EXIT_SUCCESS;
}