openbsd-compat/bsd-asprintf.c

   1 /*
   2  * Copyright (c) 2004 Darren Tucker.
   3  *
   4  * Based originally on asprintf.c from OpenBSD:
   5  * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #include "includes.h"
  21
  22 #ifndef HAVE_VASPRINTF
  23
  24 #include <errno.h>
  25 #include <stdarg.h>
  26 #include <stdlib.h>
  27
  28 #ifndef VA_COPY
  29 # ifdef HAVE_VA_COPY
  30 #  define VA_COPY(dest, src) va_copy(dest, src)
  31 # else
  32 #  ifdef HAVE___VA_COPY
  33 #   define VA_COPY(dest, src) __va_copy(dest, src)
  34 #  else
  35 #   define VA_COPY(dest, src) (dest) = (src)
  36 #  endif
  37 # endif
  38 #endif
  39
  40 #define INIT_SZ 128
  41
  42 int vasprintf(char **str, const char *fmt, va_list ap)
  43 {
  44         int ret = -1;
  45         va_list ap2;
  46         char *string, *newstr;
  47         size_t len;
  48
  49         VA_COPY(ap2, ap);
  50         if ((string = malloc(INIT_SZ)) == NULL)
  51                 goto fail;
  52
  53         ret = vsnprintf(string, INIT_SZ, fmt, ap2);
  54         if (ret >= 0 && ret < INIT_SZ) { /* succeeded with initial alloc */
  55                 *str = string;
  56         } else if (ret == INT_MAX) { /* shouldn't happen */
  57                 goto fail;
  58         } else {        /* bigger than initial, realloc allowing for nul */
  59                 len = (size_t)ret + 1;
  60                 if ((newstr = realloc(string, len)) == NULL) {
  61                         free(string);
  62                         goto fail;
  63                 } else {
  64                         va_end(ap2);
  65                         VA_COPY(ap2, ap);
  66                         ret = vsnprintf(newstr, len, fmt, ap2);
  67                         if (ret >= 0 && (size_t)ret < len) {
  68                                 *str = newstr;
  69                         } else { /* failed with realloc'ed string, give up */
  70                                 free(newstr);
  71                                 goto fail;
  72                         }
  73                 }
  74         }
  75         va_end(ap2);
  76         return (ret);
  77
  78 fail:
  79         *str = NULL;
  80         errno = ENOMEM;
  81         va_end(ap2);
  82         return (-1);
  83 }
  84 #endif
  85
  86 #ifndef HAVE_ASPRINTF
  87 int asprintf(char **str, const char *fmt, ...)
  88 {
  89         va_list ap;
  90         int ret;
  91
  92         *str = NULL;
  93         va_start(ap, fmt);
  94         ret = vasprintf(str, fmt, ap);
  95         va_end(ap);
  96
  97         return ret;
  98 }
  99 #endif