1 /* strerror_r.c --- POSIX compatible system error routine
3 Copyright (C) 2010-2011 Free Software Foundation, Inc.
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18 /* Written by Bruno Haible <bruno@clisp.org>, 2010. */
22 /* Enable declaration of sys_nerr and sys_errlist in <errno.h> on NetBSD. */
23 #define _NETBSD_SOURCE 1
32 #include "strerror-override.h"
34 #if (__GLIBC__ >= 2 || defined __UCLIBC__ || defined __CYGWIN__) && HAVE___XPG_STRERROR_R /* glibc >= 2.3.4, cygwin >= 1.7.9 */
36 # define USE_XPG_STRERROR_R 1
38 #elif HAVE_DECL_STRERROR_R && !(__GLIBC__ >= 2 || defined __UCLIBC__ || defined __CYGWIN__)
40 /* The system's strerror_r function is OK, except that its third argument
41 is 'int', not 'size_t', or its return type is wrong. */
45 # define USE_SYSTEM_STRERROR_R 1
47 #else /* (__GLIBC__ >= 2 || defined __UCLIBC__ || defined __CYGWIN__ ? !HAVE___XPG_STRERROR_R : !HAVE_DECL_STRERROR_R) */
49 /* Use the system's strerror(). Exclude glibc and cygwin because the
50 system strerror_r has the wrong return type, and cygwin 1.7.9
51 strerror_r clobbers strerror. */
54 # define USE_SYSTEM_STRERROR 1
56 # if defined __NetBSD__ || defined __hpux || ((defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__) || defined __sgi || (defined __sun && !defined _LP64) || defined __CYGWIN__
58 /* No locking needed. */
60 /* Get catgets internationalization functions. */
62 # include <nl_types.h>
65 /* Get sys_nerr, sys_errlist on HP-UX (otherwise only declared in C++ mode).
66 Get sys_nerr, sys_errlist on IRIX (otherwise only declared with _SGIAPI). */
67 # if defined __hpux || defined __sgi
69 extern char *sys_errlist[];
72 /* Get sys_nerr on Solaris. */
73 # if defined __sun && !defined _LP64
79 # include "glthread/lock.h"
81 /* This lock protects the buffer returned by strerror(). We assume that
82 no other uses of strerror() exist in the program. */
83 gl_lock_define_initialized(static, strerror_lock)
89 /* On MSVC, there is no snprintf() function, just a _snprintf().
90 It is of lower quality, but sufficient for the simple use here.
91 We only have to make sure to NUL terminate the result (_snprintf
92 does not NUL terminate, like strncpy). */
95 local_snprintf (char *buf, size_t buflen, const char *format, ...)
100 va_start (args, format);
101 result = _vsnprintf (buf, buflen, format, args);
103 if (buflen > 0 && (result < 0 || result >= buflen))
104 buf[buflen - 1] = '\0';
107 # define snprintf local_snprintf
110 /* Copy as much of MSG into BUF as possible, without corrupting errno.
111 Return 0 if MSG fit in BUFLEN, otherwise return ERANGE. */
113 safe_copy (char *buf, size_t buflen, const char *msg)
115 size_t len = strlen (msg);
120 /* Although POSIX allows memcpy() to corrupt errno, we don't
121 know of any implementation where this is a real problem. */
122 memcpy (buf, msg, len + 1);
127 memcpy (buf, msg, buflen - 1);
128 buf[buflen - 1] = '\0';
136 strerror_r (int errnum, char *buf, size_t buflen)
139 /* Filter this out now, so that rest of this replacement knows that
140 there is room for a non-empty message and trailing NUL. */
149 /* Check for gnulib overrides. */
151 char const *msg = strerror_override (errnum);
154 return safe_copy (buf, buflen, msg);
159 int saved_errno = errno;
161 #if USE_XPG_STRERROR_R
164 extern int __xpg_strerror_r (int errnum, char *buf, size_t buflen);
166 ret = __xpg_strerror_r (errnum, buf, buflen);
171 /* glibc 2.13 would not touch buf on err, so we have to fall
172 back to GNU strerror_r which always returns a thread-safe
173 untruncated string to (partially) copy into our buf. */
174 safe_copy (buf, buflen, strerror_r (errnum, buf, buflen));
178 #elif USE_SYSTEM_STRERROR_R
180 if (buflen > INT_MAX)
184 /* On HP-UX 11.31, strerror_r always fails when buflen < 80; it
185 also fails to change buf on EINVAL. */
189 if (buflen < sizeof stackbuf)
191 ret = strerror_r (errnum, stackbuf, sizeof stackbuf);
193 ret = safe_copy (buf, buflen, stackbuf);
196 ret = strerror_r (errnum, buf, buflen);
199 ret = strerror_r (errnum, buf, buflen);
201 /* Some old implementations may return (-1, EINVAL) instead of EINVAL. */
207 /* AIX returns 0 rather than ERANGE when truncating strings; try
208 again until we are sure we got the entire string. */
209 if (!ret && strlen (buf) == buflen - 1)
211 char stackbuf[STACKBUF_LEN];
213 strerror_r (errnum, stackbuf, sizeof stackbuf);
214 len = strlen (stackbuf);
215 /* STACKBUF_LEN should have been large enough. */
216 if (len + 1 == sizeof stackbuf)
222 /* Solaris 10 does not populate buf on ERANGE. OpenBSD 4.7
223 truncates early on ERANGE rather than return a partial integer.
224 We prefer the maximal string. We set buf[0] earlier, and we
225 know of no implementation that modifies buf to be an
226 unterminated string, so this strlen should be portable in
227 practice (rather than pulling in a safer strnlen). */
228 if (ret == ERANGE && strlen (buf) < buflen - 1)
230 char stackbuf[STACKBUF_LEN];
232 /* STACKBUF_LEN should have been large enough. */
233 if (strerror_r (errnum, stackbuf, sizeof stackbuf) == ERANGE)
235 safe_copy (buf, buflen, stackbuf);
239 #else /* USE_SYSTEM_STRERROR */
241 /* Try to do what strerror (errnum) does, but without clobbering the
242 buffer used by strerror(). */
244 # if defined __NetBSD__ || defined __hpux || ((defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__) || defined __CYGWIN__ /* NetBSD, HP-UX, native Win32, Cygwin */
246 /* NetBSD: sys_nerr, sys_errlist are declared through _NETBSD_SOURCE
248 HP-UX: sys_nerr, sys_errlist are declared explicitly above.
249 native Win32: sys_nerr, sys_errlist are declared in <stdlib.h>.
250 Cygwin: sys_nerr, sys_errlist are declared in <errno.h>. */
251 if (errnum >= 0 && errnum < sys_nerr)
253 # if HAVE_CATGETS && (defined __NetBSD__ || defined __hpux)
254 # if defined __NetBSD__
255 nl_catd catd = catopen ("libc", NL_CAT_LOCALE);
258 ? catgets (catd, 1, errnum, sys_errlist[errnum])
259 : sys_errlist[errnum]);
262 nl_catd catd = catopen ("perror", NL_CAT_LOCALE);
265 ? catgets (catd, 1, 1 + errnum, sys_errlist[errnum])
266 : sys_errlist[errnum]);
269 const char *errmsg = sys_errlist[errnum];
271 if (errmsg == NULL || *errmsg == '\0')
274 ret = safe_copy (buf, buflen, errmsg);
275 # if HAVE_CATGETS && (defined __NetBSD__ || defined __hpux)
276 if (catd != (nl_catd)-1)
283 # elif defined __sgi || (defined __sun && !defined _LP64) /* IRIX, Solaris <= 9 32-bit */
285 /* For a valid error number, the system's strerror() function returns
286 a pointer to a not copied string, not to a buffer. */
287 if (errnum >= 0 && errnum < sys_nerr)
289 char *errmsg = strerror (errnum);
291 if (errmsg == NULL || *errmsg == '\0')
294 ret = safe_copy (buf, buflen, errmsg);
301 gl_lock_lock (strerror_lock);
304 char *errmsg = strerror (errnum);
306 /* For invalid error numbers, strerror() on
307 - IRIX 6.5 returns NULL,
308 - HP-UX 11 returns an empty string. */
309 if (errmsg == NULL || *errmsg == '\0')
312 ret = safe_copy (buf, buflen, errmsg);
315 gl_lock_unlock (strerror_lock);
321 if (ret == EINVAL && !*buf)
322 snprintf (buf, buflen, "Unknown error %d", errnum);