usr/src/lib/libresolv2/common/bsd/strerror.c

   1 /*
   2  * Copyright (c) 1988, 1993
   3  *    The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "port_before.h"
  35
  36 #include <sys/param.h>
  37 #include <sys/types.h>
  38
  39 #include <string.h>
  40
  41 #include "port_after.h"
  42
  43 #ifndef NEED_STRERROR
  44 int __strerror_unneeded__;
  45 #else
  46
  47 #ifdef USE_SYSERROR_LIST
  48 extern int sys_nerr;
  49 extern char *sys_errlist[];
  50 #endif
  51
  52 const char *
  53 isc_strerror(int num) {
  54 #define UPREFIX "Unknown error: "
  55         static char ebuf[40] = UPREFIX;         /*%< 64-bit number + slop */
  56         u_int errnum;
  57         char *p, *t;
  58 #ifndef USE_SYSERROR_LIST
  59         const char *ret;
  60 #endif
  61         char tmp[40];
  62
  63         errnum = num;                           /*%< convert to unsigned */
  64 #ifdef USE_SYSERROR_LIST
  65         if (errnum < (u_int)sys_nerr)
  66                 return (sys_errlist[errnum]);
  67 #else
  68 #undef strerror
  69         ret = strerror(num);                    /*%< call strerror() in libc */
  70         if (ret != NULL)
  71                 return(ret);
  72 #endif
  73
  74         /* Do this by hand, so we don't include stdio(3). */
  75         t = tmp;
  76         do {
  77                 *t++ = "0123456789"[errnum % 10];
  78         } while (errnum /= 10);
  79         for (p = ebuf + sizeof(UPREFIX) - 1;;) {
  80                 *p++ = *--t;
  81                 if (t <= tmp)
  82                         break;
  83         }
  84         return (ebuf);
  85 }
  86
  87 #endif /*NEED_STRERROR*/
  88
  89 /*! \file */