strerror_r: fix AIX test failures

Already documented as an AIX limitation.

* lib/strerror_r.c (strerror_r): Convert silent truncation to
ERANGE failure.

Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 19 insertions, 1 deletions

diff --git a/lib/strerror_r.c b/lib/strerror_r.c
index f6ce8a3248..034c22e93f 100644
--- a/lib/strerror_r.c
+++ b/lib/strerror_r.c
@@ -473,7 +473,8 @@ strerror_r (int errnum, char *buf, size_t buflen)
       buflen = INT_MAX;
 
 # ifdef __hpux
-    /* On HP-UX 11.31, strerror_r always fails when buflen < 80.  */
+    /* On HP-UX 11.31, strerror_r always fails when buflen < 80; it
+       also fails to change buf on EINVAL.  */
     {
       char stackbuf[80];
 
@@ -501,6 +502,23 @@ strerror_r (int errnum, char *buf, size_t buflen)
       }
 # endif
 
+# ifdef _AIX
+    /* AIX returns 0 rather than ERANGE when truncating strings; try
+       again until we are sure we got the entire string.  */
+    if (!ret && strlen (buf) == buflen - 1)
+      {
+        char stackbuf[STACKBUF_LEN];
+        size_t len;
+        strerror_r (errnum, stackbuf, sizeof stackbuf);
+        len = strlen (stackbuf);
+        /* stackbuf should have been large enough.  */
+        if (len + 1 == sizeof stackbuf)
+          abort ();
+        if (buflen <= len)
+          ret = ERANGE;
+      }
+# endif
+
     /* Some old implementations may return (-1, EINVAL) instead of EINVAL.  */
     if (ret < 0)
       ret = errno;