lib/libc/stdio/vasprintf.c

   1 /*      $NetBSD: vasprintf.c,v 1.14 2012/03/15 18:22:30 christos Exp $  */
   2
   3 /*
   4  * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. The name of the author may not be used to endorse or promote products
  16  *    derived from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  19  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
  21  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  22  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  23  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  24  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  25  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  26  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  27  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31 #if defined(LIBC_SCCS) && !defined(lint)
  32 __RCSID("$NetBSD: vasprintf.c,v 1.14 2012/03/15 18:22:30 christos Exp $");
  33 #endif /* LIBC_SCCS and not lint */
  34
  35 #include <assert.h>
  36 #include <errno.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include "reentrant.h"
  40 #include "local.h"
  41
  42 int
  43 vasprintf(char **str, const char *fmt, va_list ap)
  44 {
  45         int ret;
  46         FILE f;
  47         struct __sfileext fext;
  48         unsigned char *_base;
  49
  50         _DIAGASSERT(str != NULL);
  51         _DIAGASSERT(fmt != NULL);
  52
  53         _FILEEXT_SETUP(&f, &fext);
  54         f._file = -1;
  55         f._flags = __SWR | __SSTR | __SALC;
  56         f._bf._base = f._p = (unsigned char *)malloc(128);
  57         if (f._bf._base == NULL)
  58                 goto err;
  59         f._bf._size = f._w = 127;               /* Leave room for the NUL */
  60         ret = __vfprintf_unlocked(&f, fmt, ap);
  61         if (ret == -1)
  62                 goto err;
  63         *f._p = '\0';
  64         _base = realloc(f._bf._base, (size_t)(ret + 1));
  65         if (_base == NULL)
  66                 goto err;
  67         *str = (char *)_base;
  68         return ret;
  69
  70 err:
  71         if (f._bf._base)
  72                 free(f._bf._base);
  73         *str = NULL;
  74         errno = ENOMEM;
  75         return -1;
  76 }