[PATCH 3/4] ptsname_r: port to Solaris

[Eric Blake]

Blindly implementing ptsname_r from scratch using the glibc
algorithm fails on Solaris 10, where isatty() doesn't set errno
when returning 0.  While not thread-safe, wrapping ptsname()
instead of implementing things ourselves has better results.

* m4/ptsname_r.m4 (gl_FUNC_PTSNAME_R): Also check for ptsname.
* m4/ptsname.m4 (gl_FUNC_PTSNAME): Optimize check.
* lib/ptsname_r.c (ptsname_r): Provide wrapper around ptsname,
when it is available, since Solaris isatty doesn't set errno.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog       |    6 +++++
 lib/ptsname_r.c |   62 +++++++++++++++++++++++++++++++++++++++----------------
 m4/ptsname.m4   |    4 +-
 m4/ptsname_r.m4 |    4 +-
 4 files changed, 54 insertions(+), 22 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 379dd63..70172b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2011-11-07  Eric Blake  <address@hidden>

+       ptsname_r: port to Solaris
+       * m4/ptsname_r.m4 (gl_FUNC_PTSNAME_R): Also check for ptsname.
+       * m4/ptsname.m4 (gl_FUNC_PTSNAME): Optimize check.
+       * lib/ptsname_r.c (ptsname_r): Provide wrapper around ptsname,
+       when it is available, since Solaris isatty doesn't set errno.
+
        ptsname_r-tests: new test module
        * modules/ptsname_r-tests: New module.
        * tests/test-ptsname_r.c: New file.
diff --git a/lib/ptsname_r.c b/lib/ptsname_r.c
index e7f2d5b..e200f34 100644
--- a/lib/ptsname_r.c
+++ b/lib/ptsname_r.c
@@ -20,26 +20,51 @@

 #include <errno.h>
 #include <string.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-#ifdef _LIBC
-# include <paths.h>
-#else
-# ifndef _PATH_TTY
-#  define _PATH_TTY "/dev/tty"
-# endif
-# ifndef _PATH_DEV
-#  define _PATH_DEV "/dev/"
-# endif

-# define __set_errno(e) errno = (e)
-# define __isatty isatty
-# define __stat stat
-# define __ttyname_r ttyname_r
-# define __ptsname_r ptsname_r
+#if HAVE_PTSNAME

-#endif
+/* Store at most BUFLEN characters of the pathname of the slave pseudo
+   terminal associated with the master FD is open on in BUF.
+   Return 0 on success, otherwise an error number.  */
+int
+ptsname_r (int fd, char *buf, size_t buflen)
+{
+  /* This assumes nothing else directly calls ptsname().  */
+  char *name;
+
+  if (!buf)
+    return errno = EINVAL;
+  name = ptsname (fd);
+  if (!name)
+    return errno;
+  if (buflen <= strlen (name))
+    return errno = ERANGE;
+  strcpy (buf, name);
+  return 0;
+}
+
+#else /* !HAVE_PTSNAME */
+
+# include <sys/stat.h>
+# include <unistd.h>
+
+# ifdef _LIBC
+#  include <paths.h>
+# else
+#  ifndef _PATH_TTY
+#   define _PATH_TTY "/dev/tty"
+#  endif
+#  ifndef _PATH_DEV
+#   define _PATH_DEV "/dev/"
+#  endif
+
+#  define __set_errno(e) errno = (e)
+#  define __isatty isatty
+#  define __stat stat
+#  define __ttyname_r ttyname_r
+#  define __ptsname_r ptsname_r
+
+# endif


 /* Store at most BUFLEN characters of the pathname of the slave pseudo
@@ -83,3 +108,4 @@ __ptsname_r (int fd, char *buf, size_t buflen)
   __set_errno (save_errno);
   return 0;
 }
+#endif /* !HAVE_PTSNAME */
diff --git a/m4/ptsname.m4 b/m4/ptsname.m4
index 4dba5f3..2403cd1 100644
--- a/m4/ptsname.m4
+++ b/m4/ptsname.m4
@@ -1,4 +1,4 @@
-# ptsname.m4 serial 2
+# ptsname.m4 serial 3
 dnl Copyright (C) 2010-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,7 +11,7 @@ AC_DEFUN([gl_FUNC_PTSNAME],
   dnl Persuade glibc <stdlib.h> to declare ptsname().
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])

-  AC_CHECK_FUNCS([ptsname])
+  AC_CHECK_FUNCS_ONCE([ptsname])
   if test $ac_cv_func_ptsname = no; then
     HAVE_PTSNAME=0
   fi
diff --git a/m4/ptsname_r.m4 b/m4/ptsname_r.m4
index fb07099..cbc3029 100644
--- a/m4/ptsname_r.m4
+++ b/m4/ptsname_r.m4
@@ -1,4 +1,4 @@
-# ptsname_r.m4 serial 1
+# ptsname_r.m4 serial 2
 dnl Copyright (C) 2010-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,7 +11,7 @@ AC_DEFUN([gl_FUNC_PTSNAME_R],
   dnl Persuade glibc <stdlib.h> to declare ptsname_r().
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])

-  AC_CHECK_FUNCS_ONCE([ptsname_r])
+  AC_CHECK_FUNCS_ONCE([ptsname ptsname_r])
   if test $ac_cv_func_ptsname_r = no; then
     HAVE_PTSNAME_R=0
   fi
-- 
1.7.4.4