lib/libc/stdio/asprintf.c

   1 /*      $NetBSD: asprintf.c,v 1.19 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: asprintf.c,v 1.19 2012/03/15 18:22:30 christos Exp $");
  33 #endif /* LIBC_SCCS and not lint */
  34
  35 #include "namespace.h"
  36 #include <assert.h>
  37 #include <stdarg.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <errno.h>
  41
  42 #include "reentrant.h"
  43 #include "local.h"
  44
  45 #ifdef __weak_alias
  46 __weak_alias(asprintf, _asprintf)
  47 #endif
  48
  49 int
  50 asprintf(char **str, char const *fmt, ...)
  51 {
  52         int ret;
  53         va_list ap;
  54         FILE f;
  55         struct __sfileext fext;
  56         unsigned char *_base;
  57
  58         _DIAGASSERT(str != NULL);
  59
  60         _FILEEXT_SETUP(&f, &fext);
  61         f._file = -1;
  62         f._flags = __SWR | __SSTR | __SALC;
  63         f._bf._base = f._p = malloc((size_t)128);
  64         if (f._bf._base == NULL)
  65                 goto err;
  66         f._bf._size = f._w = 127;               /* Leave room for the NUL */
  67         va_start(ap, fmt);
  68         ret = __vfprintf_unlocked(&f, fmt, ap);
  69         va_end(ap);
  70         if (ret < 0)
  71                 goto err;
  72         *f._p = '\0';
  73         _base = realloc(f._bf._base, (size_t)ret + 1);
  74         if (_base == NULL)
  75                 goto err;
  76         *str = (char *)_base;
  77         return ret;
  78
  79 err:
  80         if (f._bf._base)
  81                 free(f._bf._base);
  82         *str = NULL;
  83         errno = ENOMEM;
  84         return -1;
  85 }