gnulib update

[bpt/guile.git] / lib / pipe2.c

diff --git a/lib/pipe2.c b/lib/pipe2.c
new file mode 100644 (file)
index 0000000..e1884fa
--- /dev/null
+++ b/lib/pipe2.c
@@ -0,0 +1,151 @@
+/* Create a pipe, with specific opening flags.
+   Copyright (C) 2009-2011 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License along
+   with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <unistd.h>
+
+#include <errno.h>
+#include <fcntl.h>
+
+#include "binary-io.h"
+#include "verify.h"
+
+#if GNULIB_defined_O_NONBLOCK
+# include "nonblocking.h"
+#endif
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+/* Native Woe32 API.  */
+
+# include <io.h>
+
+#endif
+
+int
+pipe2 (int fd[2], int flags)
+{
+#if HAVE_PIPE2
+# undef pipe2
+  /* Try the system call first, if it exists.  (We may be running with a glibc
+     that has the function but with an older kernel that lacks it.)  */
+  {
+    /* Cache the information whether the system call really exists.  */
+    static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */
+    if (have_pipe2_really >= 0)
+      {
+        int result = pipe2 (fd, flags);
+        if (!(result < 0 && errno == ENOSYS))
+          {
+            have_pipe2_really = 1;
+            return result;
+          }
+        have_pipe2_really = -1;
+      }
+  }
+#endif
+
+  /* Check the supported flags.  */
+  if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_BINARY | O_TEXT)) != 0)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+/* Native Woe32 API.  */
+
+  if (_pipe (fd, 4096, flags & ~O_NONBLOCK) < 0)
+    return -1;
+
+  /* O_NONBLOCK handling.
+     On native Windows platforms, O_NONBLOCK is defined by gnulib.  Use the
+     functions defined by the gnulib module 'nonblocking'.  */
+# if GNULIB_defined_O_NONBLOCK
+  if (flags & O_NONBLOCK)
+    {
+      if (set_nonblocking_flag (fd[0], true) != 0
+          || set_nonblocking_flag (fd[1], true) != 0)
+        goto fail;
+    }
+# else
+  verify (O_NONBLOCK == 0);
+# endif
+
+  return 0;
+
+#else
+/* Unix API.  */
+
+  if (pipe (fd) < 0)
+    return -1;
+
+  /* POSIX <http://www.opengroup.org/onlinepubs/9699919799/functions/pipe.html>
+     says that initially, the O_NONBLOCK and FD_CLOEXEC flags are cleared on
+     both fd[0] and fd[1].  */
+
+  /* O_NONBLOCK handling.
+     On Unix platforms, O_NONBLOCK is defined by the system.  Use fcntl().  */
+  if (flags & O_NONBLOCK)
+    {
+      int fcntl_flags;
+
+      if ((fcntl_flags = fcntl (fd[1], F_GETFL, 0)) < 0
+          || fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1
+          || (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
+          || fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1)
+        goto fail;
+    }
+
+  if (flags & O_CLOEXEC)
+    {
+      int fcntl_flags;
+
+      if ((fcntl_flags = fcntl (fd[1], F_GETFD, 0)) < 0
+          || fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1
+          || (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
+          || fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
+        goto fail;
+    }
+
+# if O_BINARY
+  if (flags & O_BINARY)
+    {
+      setmode (fd[1], O_BINARY);
+      setmode (fd[0], O_BINARY);
+    }
+  else if (flags & O_TEXT)
+    {
+      setmode (fd[1], O_TEXT);
+      setmode (fd[0], O_TEXT);
+    }
+# endif
+
+  return 0;
+
+#endif
+
+ fail:
+  {
+    int saved_errno = errno;
+    close (fd[0]);
+    close (fd[1]);
+    errno = saved_errno;
+    return -1;
+  }
+}