#endif
+/* Copy as much of MSG into BUF as possible, without corrupting errno.
+ Return 0 if MSG fit in BUFLEN, otherwise return ERANGE. */
+static int
+safe_copy (char *buf, size_t buflen, const char *msg)
+{
+ size_t len = strlen (msg);
+ int ret;
+
+ if (len < buflen)
+ {
+ /* Although POSIX allows memcpy() to corrupt errno, we don't
+ know of any implementation where this is a real problem. */
+ memcpy (buf, msg, len + 1);
+ ret = 0;
+ }
+ else
+ {
+ memcpy (buf, msg, buflen - 1);
+ buf[buflen - 1] = '\0';
+ ret = ERANGE;
+ }
+ return ret;
+}
+
int
strerror_r (int errnum, char *buf, size_t buflen)
if (buflen <= 1)
{
if (buflen)
- *buf = 0;
+ *buf = '\0';
return ERANGE;
}
+ *buf = '\0';
#if GNULIB_defined_ETXTBSY \
|| GNULIB_defined_ESOCK \
}
if (msg)
- {
- int saved_errno = errno;
- size_t len = strlen (msg);
- int ret = ERANGE;
-
- if (len < buflen)
- {
- memcpy (buf, msg, len + 1);
- ret = 0;
- }
- errno = saved_errno;
- return ret;
- }
+ return safe_copy (buf, buflen, msg);
}
#endif
ret = __xpg_strerror_r (errnum, buf, buflen);
if (ret < 0)
ret = errno;
+ if (!*buf)
+ {
+ /* glibc 2.13 would not touch buf on err, so we have to fall
+ back to GNU strerror_r which always returns a thread-safe
+ untruncated string to (partially) copy into our buf. */
+ safe_copy (buf, buflen, strerror_r (errnum, buf, buflen));
+ }
}
#elif USE_SYSTEM_STRERROR_R
{
char stackbuf[80];
- if (buflen < sizeof (stackbuf))
+ if (buflen < sizeof stackbuf)
{
- ret = strerror_r (errnum, stackbuf, sizeof (stackbuf));
+ ret = strerror_r (errnum, stackbuf, sizeof stackbuf);
if (ret == 0)
- {
- size_t len = strlen (stackbuf);
-
- if (len < buflen)
- memcpy (buf, stackbuf, len + 1);
- else
- ret = ERANGE;
- }
+ ret = safe_copy (buf, buflen, stackbuf);
}
else
ret = strerror_r (errnum, buf, buflen);
/* FreeBSD rejects 0; see http://austingroupbugs.net/view.php?id=382. */
if (errnum == 0 && ret == EINVAL)
- {
- if (buflen <= strlen ("Success"))
- {
- ret = ERANGE;
- if (buflen)
- buf[0] = 0;
- }
- else
- {
- ret = 0;
- strcpy (buf, "Success");
- }
- }
+ ret = safe_copy (buf, buflen, "Success");
#else /* USE_SYSTEM_STRERROR */
if (errmsg == NULL || *errmsg == '\0')
ret = EINVAL;
else
- {
- size_t len = strlen (errmsg);
-
- if (len < buflen)
- {
- memcpy (buf, errmsg, len + 1);
- ret = 0;
- }
- else
- ret = ERANGE;
- }
+ ret = safe_copy (buf, buflen, errmsg);
# if HAVE_CATGETS && (defined __NetBSD__ || defined __hpux)
if (catd != (nl_catd)-1)
catclose (catd);
if (errmsg == NULL || *errmsg == '\0')
ret = EINVAL;
else
- {
- size_t len = strlen (errmsg);
-
- if (len < buflen)
- {
- memcpy (buf, errmsg, len + 1);
- ret = 0;
- }
- else
- ret = ERANGE;
- }
+ ret = safe_copy (buf, buflen, errmsg);
}
else
ret = EINVAL;
if (errmsg == NULL || *errmsg == '\0')
ret = EINVAL;
else
- {
- size_t len = strlen (errmsg);
-
- if (len < buflen)
- {
- memcpy (buf, errmsg, len + 1);
- ret = 0;
- }
- else
- ret = ERANGE;
- }
+ ret = safe_copy (buf, buflen, errmsg);
}
gl_lock_unlock (strerror_lock);
#endif
+ if (ret == EINVAL && !*buf)
+ snprintf (buf, buflen, "Unknown error %d", errnum);
+
errno = saved_errno;
return ret;
}