/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright © 2020 Keith Packard
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials provided
 *    with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "stdio_private.h"

char * __disable_sanitizer
vasnprintf(char *str, size_t *lenp, const char *fmt, va_list ap)
{
    struct __file_str f = FDEV_SETUP_STRING_ALLOC_BUF(str, *lenp);
    int               i;

    i = vfprintf(&f.file, fmt, ap);

    /*
     * Use fputc to append a NULL to handle
     * buffer overflow cases
     */
    if (i >= 0) {
        if (fputc('\0', &f.file) < 0)
            i = EOF;
    }

    char *ret = POINTER_MINUS(f.end, f.size);

    if (i >= 0) {
        *lenp = (size_t)i;
        /* Try to shrink the buffer */
        if (f.alloc) {
            char *s = realloc(ret, i + 1);
            if (s)
                ret = s;
        }
    } else {
        if (f.alloc)
            free(ret);
        ret = NULL;
    }
    return ret;
}
