/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 2004 Darren Tucker.
 * Copyright 2022 Oxide Computer Company
 *
 * Based originally on asprintf.c from OpenBSD:
 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <lint.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <errno.h>

#define INIT_SZ 128

int
vasprintf(char **str, const char *format, va_list ap)
{
        char string[INIT_SZ];
        char *newstr;
        int ret;
        size_t len;

        *str = NULL;
        ret = vsnprintf(string, INIT_SZ, format, ap);
        if (ret < 0)    /* retain the value of errno from vsnprintf() */
                return (-1);
        if (ret < INIT_SZ) {
                len = ret + 1;
                if ((newstr = malloc(len)) == NULL)
                        return (-1);    /* retain errno from malloc() */
                /*
                 * Prior versions of this used strlcpy. This has two problems.
                 * One, it doesn't handle embedded '\0' characters. Secondly,
                 * it's recalculating the length we already know. Please do not
                 * use a string-based copying function.
                 */
                (void) memcpy(newstr, string, len);
                *str = newstr;
                return (ret);
        }
        /*
         * We will perform this loop more than once only if some other
         * thread modifies one of the vasprintf() arguments after our
         * previous call to vsnprintf().
         */
        for (;;) {
                if (ret == INT_MAX) {   /* Bad length */
                        errno = ENOMEM;
                        return (-1);
                }
                len = ret + 1;
                if ((newstr = malloc(len)) == NULL)
                        return (-1);    /* retain errno from malloc() */
                ret = vsnprintf(newstr, len, format, ap);
                if (ret < 0) {          /* retain errno from vsnprintf() */
                        free(newstr);
                        return (-1);
                }
                if (ret < len) {
                        *str = newstr;
                        return (ret);
                }
                free(newstr);
        }
}

int
asprintf(char **str, const char *format, ...)
{
        va_list ap;
        int ret;

        *str = NULL;
        va_start(ap, format);
        ret = vasprintf(str, format, ap);
        va_end(ap);

        return (ret);
}