diff options
Diffstat (limited to 'tests/strerror_r.c')
| -rw-r--r-- | tests/strerror_r.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/tests/strerror_r.c b/tests/strerror_r.c index 85a21893..b154c292 100644 --- a/tests/strerror_r.c +++ b/tests/strerror_r.c @@ -166,16 +166,19 @@ strerror_r (int errnum, char *buf, size_t buflen) # if HAVE___XPG_STRERROR_R ret = __xpg_strerror_r (errnum, buf, buflen); - if (ret < 0) - ret = errno; + /* ret is 0 upon success, or EINVAL or ERANGE upon failure. */ # endif 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. */ - char *errstring = strerror_r (errnum, buf, buflen); + /* glibc 2.13 ... 2.34 (at least) don't touch buf upon failure. + Therefore we have to fall back to strerror_r which, for valid + errnum, returns a thread-safe untruncated string. For invalid + errnum, though, it returns a truncated string, which does not + allow us to determine whether to return ERANGE or 0. Thus we + need to pass a sufficiently large buffer. */ + char stackbuf[80]; + char *errstring = strerror_r (errnum, stackbuf, sizeof stackbuf); ret = errstring ? safe_copy (buf, buflen, errstring) : errno; } } |