lib/libc/string/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  * $FreeBSD: src/lib/libc/string/strerror.c,v 1.2.14.3 2003/01/17 13:39:32 mike Exp $
  34  * $DragonFly: src/lib/libc/string/strerror.c,v 1.2 2003/06/17 04:26:46 dillon Exp $
  35  */
  36
  37 #include <errno.h>
  38 #include <stdio.h>
  39 #include <string.h>
  40
  41 #define UPREFIX         "Unknown error: "
  42
  43 /*
  44  * Define a buffer size big enough to describe a 64-bit signed integer
  45  * converted to ASCII decimal (19 bytes), with an optional leading sign
  46  * (1 byte); finally, we get the prefix and a trailing NUL from UPREFIX.
  47  */
  48 #define EBUFSIZE        (20 + sizeof(UPREFIX))
  49
  50 /*
  51  * Doing this by hand instead of linking with stdio(3) avoids bloat for
  52  * statically linked binaries.
  53  */
  54 static void
  55 errstr(int num, char *buf, size_t len)
  56 {
  57         char *t;
  58         unsigned int uerr;
  59         char tmp[EBUFSIZE];
  60
  61         t = tmp + sizeof(tmp);
  62         *--t = '\0';
  63         uerr = (num >= 0) ? num : -num;
  64         do {
  65                 *--t = "0123456789"[uerr % 10];
  66         } while (uerr /= 10);
  67         if (num < 0)
  68                 *--t = '-';
  69         strlcpy(buf, UPREFIX, len);
  70         strlcat(buf, t, len);
  71 }
  72
  73 int
  74 strerror_r(int errnum, char *strerrbuf, size_t buflen)
  75 {
  76
  77         if (errnum < 1 || errnum >= sys_nerr) {
  78                 errstr(errnum, strerrbuf, buflen);
  79                 return (EINVAL);
  80         }
  81         if (strlcpy(strerrbuf, sys_errlist[errnum], buflen) >= buflen)
  82                 return (ERANGE);
  83         return (0);
  84 }
  85
  86 char *
  87 strerror(int num)
  88 {
  89         static char ebuf[EBUFSIZE];
  90
  91         if (num > 0 && num < sys_nerr)
  92                 return ((char *)sys_errlist[num]);
  93         errno = EINVAL;
  94         errstr(num, ebuf, sizeof(ebuf));
  95         return (ebuf);
  96 }