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-rw-r--r--lib/strerror.c56
1 files changed, 34 insertions, 22 deletions
diff --git a/lib/strerror.c b/lib/strerror.c
index 4b1df9446..03ddc1a2b 100644
--- a/lib/strerror.c
+++ b/lib/strerror.c
@@ -485,12 +485,16 @@ get_winsock_error (int err, char *buf, size_t len)
}
#endif /* WIN32 && !__CYGWIN__ */
-#ifndef WIN32
-extern int sys_nerr;
-#endif
-
/*
* Our thread-safe and smart strerror() replacement.
+ *
+ * The 'err' argument passed in to this function MUST be a true errno number
+ * as reported on this system. We do no range checking on the number before
+ * we pass it to the "number-to-message" convertion function and there might
+ * be systems that don't do proper range checking in there themselves.
+ *
+ * We don't do range checking (on systems other than Windows) since there is
+ * no good reliable and portable way to do it.
*/
const char *Curl_strerror(struct connectdata *conn, int err)
{
@@ -498,37 +502,45 @@ const char *Curl_strerror(struct connectdata *conn, int err)
size_t max;
curlassert(conn);
+ curlassert(err >= 0);
buf = conn->syserr_buf;
max = sizeof(conn->syserr_buf)-1;
*buf = '\0';
+
+#if defined(WIN32) && !defined(__CYGWIN__)
+ /* 'sys_nerr' is the maximum errno number, it is not widely portable */
if (err >= 0 && err < sys_nerr) {
- /* These should be atomic and hopefully thread-safe */
+ if (!get_winsock_error (err, buf, max) &&
+ !FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM, NULL, err,
+ LANG_NEUTRAL, buf, max, NULL))
+ snprintf(buf, max, "Unknown error %d (%#x)", err, err);
+ }
+#else /* not native Windows coming up */
+
+ /* These should be atomic and hopefully thread-safe */
#ifdef HAVE_STRERROR_R
+ /* There are two different APIs for strerror_r(). The POSIX and the GLIBC
+ versions. */
#ifdef HAVE_POSIX_STRERROR_R
- strerror_r(err, buf, max);
- /* this may set errno to ERANGE if insufficient storage was supplied via
- strerrbuf and buflen to contain the generated message string, or EINVAL
- if the value of errnum is not a valid error number.*/
+ strerror_r(err, buf, max);
+ /* this may set errno to ERANGE if insufficient storage was supplied via
+ 'strerrbuf' and 'buflen' to contain the generated message string, or
+ EINVAL if the value of 'errnum' is not a valid error number.*/
#else
+ {
/* HAVE_GLIBC_STRERROR_R */
char buffer[256];
char *msg = strerror_r(err, buffer, sizeof(buffer));
strncpy(buf, msg, max);
-#endif
-#else
- strncpy(buf, strerror(err), max);
-#endif
- *(buf+max) = '\0';
- }
- else {
-#if defined(WIN32) && !defined(__CYGWIN__)
- if (!get_winsock_error (err, buf, max) &&
- !FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM, NULL, err,
- LANG_NEUTRAL, buf, max, NULL))
-#endif
- snprintf(buf, max, "Unknown error %d (%#x)", err, err);
}
+#endif /* end of HAVE_GLIBC_STRERROR_R */
+#else /* HAVE_STRERROR_R */
+ strncpy(buf, strerror(err), max);
+#endif /* end of HAVE_STRERROR_R */
+#endif /* end of ! Windows */
+
+ buf[max] = '\0'; /* make sure the string is zero terminated */
/* strip trailing '\r\n' or '\n'. */
if ((p = strrchr(buf,'\n')) != NULL && (p - buf) >= 2)