strerror.c revision 251069 
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. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)strerror.c	8.1 (Berkeley) 6/4/93";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: head/lib/libc/string/strerror.c 251069 2013-05-28 20:57:40Z emaste $");
35
36#if defined(NLS)
37#include <nl_types.h>
38#endif
39
40#include <limits.h>
41#include <errno.h>
42#include <string.h>
43#include <stdio.h>
44
45#define	UPREFIX		"Unknown error"
46
47/*
48 * Define a buffer size big enough to describe a 64-bit signed integer
49 * converted to ASCII decimal (19 bytes), with an optional leading sign
50 * (1 byte); finally, we get the prefix, delimiter (": ") and a trailing
51 * NUL from UPREFIX.
52 */
53#define	EBUFSIZE	(20 + 2 + sizeof(UPREFIX))
54
55/*
56 * Doing this by hand instead of linking with stdio(3) avoids bloat for
57 * statically linked binaries.
58 */
59static void
60errstr(int num, char *uprefix, char *buf, size_t len)
61{
62	char *t;
63	unsigned int uerr;
64	char tmp[EBUFSIZE];
65
66	t = tmp + sizeof(tmp);
67	*--t = '\0';
68	uerr = (num >= 0) ? num : -num;
69	do {
70		*--t = "0123456789"[uerr % 10];
71	} while (uerr /= 10);
72	if (num < 0)
73		*--t = '-';
74	*--t = ' ';
75	*--t = ':';
76	strlcpy(buf, uprefix, len);
77	strlcat(buf, t, len);
78}
79
80int
81strerror_r(int errnum, char *strerrbuf, size_t buflen)
82{
83	int retval = 0;
84#if defined(NLS)
85	int saved_errno = errno;
86	nl_catd catd;
87	catd = catopen("libc", NL_CAT_LOCALE);
88#endif
89
90	if (errnum < 0 || errnum >= sys_nerr) {
91		errstr(errnum,
92#if defined(NLS)
93			catgets(catd, 1, 0xffff, UPREFIX),
94#else
95			UPREFIX,
96#endif
97			strerrbuf, buflen);
98		retval = EINVAL;
99	} else {
100		if (strlcpy(strerrbuf,
101#if defined(NLS)
102			catgets(catd, 1, errnum, sys_errlist[errnum]),
103#else
104			sys_errlist[errnum],
105#endif
106			buflen) >= buflen)
107		retval = ERANGE;
108	}
109
110#if defined(NLS)
111	catclose(catd);
112	errno = saved_errno;
113#endif
114
115	return (retval);
116}
117
118char *
119strerror(int num)
120{
121	static char ebuf[NL_TEXTMAX];
122
123	if (strerror_r(num, ebuf, sizeof(ebuf)) != 0)
124		errno = EINVAL;
125	return (ebuf);
126}
127