root/crypto/libressl/crypto/bio/b_print.c
/* $OpenBSD: b_print.c,v 1.26 2019/06/28 05:47:57 deraadt Exp $ */

/* Theo de Raadt places this file in the public domain. */

#include <openssl/bio.h>

int
BIO_printf(BIO *bio, const char *format, ...)
{
        va_list args;
        int ret;

        va_start(args, format);
        ret = BIO_vprintf(bio, format, args);
        va_end(args);
        return (ret);
}

#ifdef HAVE_FUNOPEN
static int
_BIO_write(void *cookie, const char *buf, int nbytes)
{
        return BIO_write(cookie, buf, nbytes);
}

int
BIO_vprintf(BIO *bio, const char *format, va_list args)
{
        int ret;
        FILE *fp;

        fp = funopen(bio, NULL, &_BIO_write, NULL, NULL);
        if (fp == NULL) {
                ret = -1;
                goto fail;
        }
        ret = vfprintf(fp, format, args);
        fclose(fp);
fail:
        return (ret);
}

#else /* !HAVE_FUNOPEN */

int
BIO_vprintf(BIO *bio, const char *format, va_list args)
{
        int ret;
        char *buf = NULL;

        ret = vasprintf(&buf, format, args);
        if (ret == -1)
                return (ret);
        BIO_write(bio, buf, ret);
        free(buf);
        return (ret);
}

#endif /* HAVE_FUNOPEN */

/*
 * BIO_snprintf and BIO_vsnprintf return -1 for overflow,
 * due to the history of this API.  Justification:
 *
 * Traditional snprintf surfaced in 4.4BSD, and returned
 * "number of bytes wanted". Solaris and Windows opted to
 * return -1.  A draft standard was written which returned -1.
 * Due to the large volume of code already using the first
 * semantics, the draft was repaired before standardization to
 * specify "number of bytes wanted" plus "-1 for character conversion
 * style errors".  Solaris adapted to this rule, but Windows stuck
 * with -1.
 *
 * Original OpenSSL comment which is full of lies:
 *
 * "In case of truncation, return -1 like traditional snprintf.
 * (Current drafts for ISO/IEC 9899 say snprintf should return
 * the number of characters that would have been written,
 * had the buffer been large enough.)"
 */
int
BIO_snprintf(char *buf, size_t n, const char *format, ...)
{
        va_list args;
        int ret;

        va_start(args, format);
        ret = vsnprintf(buf, n, format, args);
        va_end(args);

        if (ret >= n || ret == -1)
                return (-1);
        return (ret);
}

int
BIO_vsnprintf(char *buf, size_t n, const char *format, va_list args)
{
        int ret;

        ret = vsnprintf(buf, n, format, args);

        if (ret >= n || ret == -1)
                return (-1);
        return (ret);
}