ttyname_r: Make it work on Solaris 10.

diff --git a/ChangeLog b/ChangeLog
index 6260fd3f2272fa150163e5301e270b05ad6cf108..9cdd83a51c5bbb7887bf7f21752b355ee291ba70 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2010-04-25  Bruno Haible  <bruno@clisp.org>
+
+       ttyname_r: Make it work on Solaris 10.
+       * m4/ttyname_r.m4 (gl_FUNC_TTYNAME_R): Define HAVE_POSIXDECL_TTYNAME_R
+       if the system function has the POSIX declaration. Test whether the
+       function fails if the buffer is less than 128 bytes large.
+       * lib/ttyname_r.c (ttyname_r): Handle both possible declarations of the
+       system's ttyname_r function. Provide a reasonably large buffer.
+       * modules/ttyname_r (Depends-on): Add extensions.
+       * doc/posix-functions/ttyname_r.texi: Mention the Solaris problem.
+
 2010-04-25  Bruno Haible  <bruno@clisp.org>
 
        Use the 'extensions' module for some more functions on Solaris.

diff --git a/doc/posix-functions/ttyname_r.texi b/doc/posix-functions/ttyname_r.texi
index 4780390e2e79f39c70588706b09a8dc508e28c15..877e4b2f66e425e342518bcbc9b4cba4c9da5d8d 100644 (file)
--- a/doc/posix-functions/ttyname_r.texi
+++ b/doc/posix-functions/ttyname_r.texi
@@ -14,6 +14,10 @@ NetBSD 3.0, mingw, BeOS.
 @item
 This function has an incompatible declaration on some platforms:
 MacOS X 10.4, Solaris 10 (when @code{_POSIX_PTHREAD_SEMANTICS} is not defined).
+@item
+This function refuses to do anything when the output buffer is less than 128
+bytes large, on some platforms:
+Solaris 10.
 @end itemize
 
 Portability problems not fixed by Gnulib:

diff --git a/lib/ttyname_r.c b/lib/ttyname_r.c
index d3e58eb21d722a984dc52b2b7d4587dcf112349e..5b59547cad84333b6d4cf908464fc8a321e25b16 100644 (file)
--- a/lib/ttyname_r.c
+++ b/lib/ttyname_r.c
@@ -29,12 +29,31 @@ int
 ttyname_r (int fd, char *buf, size_t buflen)
 #undef ttyname_r
 {
-  /* 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
+  /* When ttyname_r exists, use it.  */
+#if HAVE_TTYNAME_R
   /* This code is multithread-safe.  */
-  char *name = ttyname_r (fd, buf, buflen <= INT_MAX ? buflen : INT_MAX);
+  /* On Solaris, ttyname_r always fails if buflen < 128.  So provide a buffer
+     that is large enough.  */
+  char largerbuf[512];
+# if HAVE_POSIXDECL_TTYNAME_R
+  int err =
+    (buflen < sizeof (largerbuf)
+     ? ttyname_r (fd, largerbuf, sizeof (largerbuf))
+     : ttyname_r (fd, buf, buflen <= INT_MAX ? buflen : INT_MAX));
+  if (err != 0)
+    return err;
+  if (buflen < sizeof (largerbuf))
+    {
+      size_t namelen = strlen (largerbuf);
+      if (namelen > buflen)
+        return ERANGE;
+      memcpy (buf, largerbuf, namelen);
+    }
+# else
+  char *name =
+    (buflen < sizeof (largerbuf)
+     ? ttyname_r (fd, largerbuf, sizeof (largerbuf))
+     : ttyname_r (fd, buf, buflen <= INT_MAX ? buflen : INT_MAX));
   if (name == NULL)
     return errno;
   if (name != buf)
@@ -44,6 +63,7 @@ ttyname_r (int fd, char *buf, size_t buflen)
         return ERANGE;
       memmove (buf, name, namelen);
     }
+# endif
   return 0;
 #elif HAVE_TTYNAME
   /* Note: This is not multithread-safe.  */

diff --git a/m4/ttyname_r.m4 b/m4/ttyname_r.m4
index ce4737498d914c030bc6ca4c5447c64ed9e95952..c41d8ba81cc7ba8f6fc88be2dbe6a9704d3ff58d 100644 (file)
--- a/m4/ttyname_r.m4
+++ b/m4/ttyname_r.m4
@@ -1,4 +1,4 @@
-# ttyname_r.m4 serial 2
+# ttyname_r.m4 serial 3
 dnl Copyright (C) 2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -8,11 +8,16 @@ AC_DEFUN([gl_FUNC_TTYNAME_R],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
 
+  dnl Persuade Solaris <unistd.h> to provide the POSIX compliant declaration of
+  dnl ttyname_r().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   AC_CHECK_FUNCS([ttyname_r])
   if test $ac_cv_func_ttyname_r = no; then
     HAVE_TTYNAME_R=0
   else
-    dnl On MacOS X 10.4 and Solaris 10 the return type is 'char *', not 'int'.
+    dnl On MacOS X 10.4 (and Solaris 10 without gl_USE_SYSTEM_EXTENSIONS)
+    dnl the return type is 'char *', not 'int'.
     AC_CACHE_CHECK([whether ttyname_r is compatible with its POSIX signature],
       [gl_cv_func_ttyname_r_posix],
       [AC_COMPILE_IFELSE(
@@ -26,6 +31,47 @@ AC_DEFUN([gl_FUNC_TTYNAME_R],
       ])
     if test $gl_cv_func_ttyname_r_posix = no; then
       REPLACE_TTYNAME_R=1
+    else
+      AC_DEFINE([HAVE_POSIXDECL_TTYNAME_R], [1],
+        [Define if the ttyname_r function has a POSIX compliant declaration.])
+      dnl On Solaris 10, both ttyname_r functions (the one with the non-POSIX
+      dnl declaration and the one with the POSIX declaration) refuse to do
+      dnl anything when the output buffer is less than 128 bytes large.
+      AC_REQUIRE([AC_CANONICAL_HOST])
+      AC_CACHE_CHECK([whether ttyname_r works with small buffers],
+        [gl_cv_func_ttyname_r_works],
+        [
+          dnl Initial guess, used when cross-compiling or when /dev/tty cannot
+          dnl be opened.
+changequote(,)dnl
+          case "$host_os" in
+                      # Guess no on Solaris.
+            solaris*) gl_cv_func_ttyname_r_works="guessing no" ;;
+                      # Guess yes otherwise.
+            *)        gl_cv_func_ttyname_r_works="guessing yes" ;;
+          esac
+changequote([,])dnl
+          AC_TRY_RUN([
+#include <fcntl.h>
+#include <unistd.h>
+int
+main (void)
+{
+  int fd;
+  char buf[31]; /* use any size < 128 here */
+
+  fd = open ("/dev/tty", O_RDONLY);
+  if (fd < 0)
+    return 1;
+  if (ttyname_r (fd, buf, sizeof (buf)) != 0)
+    return 1;
+  return 0;
+}], [gl_cv_func_ttyname_r_works=yes], [:], [:])
+        ])
+      case "$gl_cv_func_ttyname_r_works" in
+        *yes) ;;
+        *) REPLACE_TTYNAME_R=1 ;;
+      esac
     fi
   fi
   if test $HAVE_TTYNAME_R = 0 || test $REPLACE_TTYNAME_R = 1; then

diff --git a/modules/ttyname_r b/modules/ttyname_r
index 1e74839ef2bdfdebdfffabb1b936f8a75c8a491b..8e79bf32c17ce96aace47e179021b9225a22adae 100644 (file)
--- a/modules/ttyname_r
+++ b/modules/ttyname_r
@@ -7,6 +7,7 @@ m4/ttyname_r.m4
 
 Depends-on:
 unistd
+extensions
 
 configure.ac:
 gl_FUNC_TTYNAME_R