2 files changed, 32 insertions, 3 deletions
diff --git a/lib/ttyname_r.c b/lib/ttyname_r.c
index dc8b923f1b..d3e58eb21d 100644
--- a/lib/ttyname_r.c
+++ b/lib/ttyname_r.c
@@ -22,12 +22,30 @@
 #include <unistd.h>
 
 #include <errno.h>
+#include <limits.h>
 #include <string.h>
 
 int
 ttyname_r (int fd, char *buf, size_t buflen)
+#undef ttyname_r
 {
-#if HAVE_TTYNAME
+  /* When ttyname_r exists and works, use it.
+     But on Solaris 10, ttyname_r is broken: it returns NULL in situations
+     when ttyname finds the result.  */
+#if HAVE_TTYNAME_R && !defined __sun
+  /* This code is multithread-safe.  */
+  char *name = ttyname_r (fd, buf, buflen <= INT_MAX ? buflen : INT_MAX);
+  if (name == NULL)
+    return errno;
+  if (name != buf)
+    {
+      size_t namelen = strlen (name) + 1;
+      if (namelen > buflen)
+        return ERANGE;
+      memmove (buf, name, namelen);
+    }
+  return 0;
+#elif HAVE_TTYNAME
   /* Note: This is not multithread-safe.  */
   char *name;
   size_t namelen;
diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index 7302d6d3e1..b1f07434ff 100644
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -1164,12 +1164,23 @@ _GL_WARN_ON_USE (symlinkat, "symlinkat is not portable - "
 #if @GNULIB_TTYNAME_R@
 /* Store at most BUFLEN characters of the pathname of the terminal FD is
    open on in BUF.  Return 0 on success, otherwise an error number.  */
-# if !@HAVE_TTYNAME_R@
+# if @REPLACE_TTYNAME_R@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef ttyname_r
+#   define ttyname_r rpl_ttyname_r
+#  endif
+_GL_FUNCDECL_RPL (ttyname_r, int,
+                  (int fd, char *buf, size_t buflen) _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (ttyname_r, int,
+                  (int fd, char *buf, size_t buflen));
+# else
+#  if !@HAVE_TTYNAME_R@
 _GL_FUNCDECL_SYS (ttyname_r, int,
                   (int fd, char *buf, size_t buflen) _GL_ARG_NONNULL ((2)));
-# endif
+#  endif
 _GL_CXXALIAS_SYS (ttyname_r, int,
                   (int fd, char *buf, size_t buflen));
+# endif
 _GL_CXXALIASWARN (ttyname_r);
 #elif defined GNULIB_POSIXCHECK
 # undef ttyname_r