xref: /netbsd-src/lib/libc/string/strerror.c (revision d9158b13b5dfe46201430699a3f7a235ecf28df3)
1 /*
2  * Copyright (c) 1988 Regents of the University of California.
3  * 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 #if defined(LIBC_SCCS) && !defined(lint)
35 /*static char *sccsid = "from: @(#)strerror.c	5.6 (Berkeley) 5/4/91";*/
36 static char *rcsid = "$Id: strerror.c,v 1.2 1993/10/09 00:11:01 jtc Exp $";
37 #endif /* LIBC_SCCS and not lint */
38 
39 #include <string.h>
40 
41 /*
42  * Since perror() is not allowed to change the contents of strerror()'s
43  * static buffer, both functions supply their own buffers to the
44  * internal function __strerror().
45  */
46 
47 char *
48 __strerror(num, buf)
49 	int num;
50 	char *buf;
51 {
52 #define	UPREFIX	"Unknown error: "
53 	extern char *sys_errlist[];
54 	extern int sys_nerr;
55 	register unsigned int errnum;
56 	register char *p, *t;
57 	char tmp[40];
58 
59 	errnum = num;				/* convert to unsigned */
60 	if (errnum < sys_nerr)
61 		return(sys_errlist[errnum]);
62 
63 	/* Do this by hand, so we don't include stdio(3). */
64 	t = tmp;
65 	do {
66 		*t++ = "0123456789"[errnum % 10];
67 	} while (errnum /= 10);
68 
69 	strcpy (buf, UPREFIX);
70 	for (p = buf + sizeof(UPREFIX) -1;;) {
71 		*p++ = *--t;
72 		if (t <= tmp)
73 			break;
74 	}
75 
76 	return buf;
77 }
78 
79 
80 char *
81 strerror(num)
82 	int num;
83 {
84 	static char buf[40];			/* 64-bit number + slop */
85 	return __strerror(num, buf);
86 }
87