[gnome-builder] terminal: fallback to ptsname() if ptsname_r() is not available

[Christian Hergert <chergert src gnome org>]

commit 6e03588cb17d07f18b73c3d9ae288fa2b60222ce
Author: Christian Hergert <chergert redhat com>
Date:   Thu Nov 3 14:28:54 2016 -0700

    terminal: fallback to ptsname() if ptsname_r() is not available
    
    We are technically safe from race-conditions here in Builder specific
    code today, as we only call ptsname_r() from the main loop. So switching
    to the MT-unsafe ptsname() is fine. However, I'd like to always use the
    re-entrant safe POSIX functions when possible.
    
    This falls back to ptsname() when ptsname_r() isn't available, such as on
    BSD variants.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=773880

 plugins/terminal/configure.ac       |   12 ++++++++++++
 plugins/terminal/gb-terminal-view.c |   11 ++++++++++-
 2 files changed, 22 insertions(+), 1 deletions(-)
---
diff --git a/plugins/terminal/configure.ac b/plugins/terminal/configure.ac
index 9cfb190..5732e86 100644
--- a/plugins/terminal/configure.ac
+++ b/plugins/terminal/configure.ac
@@ -10,6 +10,18 @@ AS_IF([test x$enable_terminal_plugin = xyes && test x$have_vte = xno],[
        AC_MSG_ERROR([Failed to locate vte dependencies. Try installing vte291-devel.])
 ])
 
+dnl We prefer ptsname_r(), but will settle for ptsname() if necessary
+AC_TRY_LINK([#ifndef _XOPEN_SOURCE
+             #define _XOPEN_SOURCE
+             #endif
+             #ifndef _GNU_SOURCE
+             #define _GNU_SOURCE
+             #endif
+             #include <stdlib.h>],
+           [char buf[10]; ptsname_r(0, buf, sizeof(buf));],
+           [AC_DEFINE(HAVE_PTSNAME_R, 1,
+                      Define to 1 if you have a re-entrant version of ptsname)])
+
 # for if ENABLE_CLANG_PLUGIN in Makefile.am
 AM_CONDITIONAL(ENABLE_TERMINAL_PLUGIN, test x$enable_terminal_plugin = xyes)
 
diff --git a/plugins/terminal/gb-terminal-view.c b/plugins/terminal/gb-terminal-view.c
index ae9b01b..62b08ec 100644
--- a/plugins/terminal/gb-terminal-view.c
+++ b/plugins/terminal/gb-terminal-view.c
@@ -193,9 +193,13 @@ gb_terminal_respawn (GbTerminalView *self,
   gint64 now;
   int master_fd = -1;
   int tty_fd = -1;
-  char name[PATH_MAX + 1];
   gint stdout_fd = -1;
   gint stderr_fd = -1;
+#ifdef HAVE_PTSNAME_R
+  char name[PATH_MAX + 1];
+#else
+  const char *name;
+#endif
 
   IDE_ENTRY;
 
@@ -255,8 +259,13 @@ gb_terminal_respawn (GbTerminalView *self,
   if (unlockpt (master_fd) != 0)
     IDE_GOTO (failure);
 
+#ifdef HAVE_PTSNAME_R
   if (ptsname_r (master_fd, name, sizeof name - 1) != 0)
     IDE_GOTO (failure);
+#else
+  if (NULL == (name = ptsname (master_fd)))
+    IDE_GOTO (failure);
+#endif
 
   if (-1 == (tty_fd = open (name, O_RDWR | O_CLOEXEC)))
     IDE_GOTO (failure);