mkfifoat: new module

* modules/mkfifoat: New file.
* lib/mkfifoat.c: Likewise.
* m4/mkfifoat.m4 (gl_FUNC_MKFIFOAT): Likewise.
* m4/sys_stat_h.m4 (gl_SYS_STAT_H_DEFAULTS): Add witnesses.
* modules/sys_stat (Makefile.am): Use them.
* lib/sys_stat.in.h (mkfifoat, mknodat): Declare them.
* MODULES.html.sh (File system functions): Mention module.
* doc/posix-functions/mkfifoat.texi (mkfifoat): Likewise.
* doc/posix-functions/mknodat.texi (mknodat): Likewise.
* modules/mkfifoat-tests: New test.
* tests/test-mkfifoat.c: Likewise.

Signed-off-by: Eric Blake <ebb9@byu.net>

1 files changed, 101 insertions, 0 deletions

diff --git a/lib/mkfifoat.c b/lib/mkfifoat.c
new file mode 100644
index 0000000000..a230b0048a
--- /dev/null
+++ b/lib/mkfifoat.c
@@ -0,0 +1,101 @@
+/* Create a named fifo relative to an open directory.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* written by Eric Blake */
+
+#include <config.h>
+
+#include <sys/stat.h>
+
+#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
+#include "openat.h"
+#include "openat-priv.h"
+#include "save-cwd.h"
+
+#ifndef HAVE_MKFIFO
+# define HAVE_MKFIFO 0
+#endif
+#ifndef HAVE_MKNOD
+# define HAVE_MKNOD 0
+#endif
+
+/* For now, all known systems either have both mkfifo and mknod, or
+   neither.  If this is not true, we can implement the portable
+   aspects of one using the other (POSIX only requires mknod to create
+   fifos; all other uses of mknod are for root users and outside the
+   realm of POSIX).  */
+#if HAVE_MKNOD != HAVE_MKFIFO
+# error Please report this message and your system to bug-gnulib@gnu.org.
+#endif
+
+#if !HAVE_MKFIFO
+/* Mingw lacks mkfifo and mknod, so this wrapper is trivial.  */
+
+# include <errno.h>
+
+int
+mkfifoat (int fd _UNUSED_PARAMETER_, char const *path _UNUSED_PARAMETER_,
+	  mode_t mode _UNUSED_PARAMETER_)
+{
+  errno = ENOSYS;
+  return -1;
+}
+
+int
+mknodat (int fd _UNUSED_PARAMETER_, char const *path _UNUSED_PARAMETER_,
+	 mode_t mode _UNUSED_PARAMETER_, dev_t dev _UNUSED_PARAMETER_)
+{
+  errno = ENOSYS;
+  return -1;
+}
+
+#else /* HAVE_MKFIFO */
+
+/* Create a named fifo FILE relative to directory FD, with access
+   permissions in MODE.  If possible, do it without changing the
+   working directory.  Otherwise, resort to using save_cwd/fchdir,
+   then mkfifo/restore_cwd.  If either the save_cwd or the restore_cwd
+   fails, then give a diagnostic and exit nonzero.  */
+
+# define AT_FUNC_NAME mkfifoat
+# define AT_FUNC_F1 mkfifo
+# define AT_FUNC_POST_FILE_PARAM_DECLS , mode_t mode
+# define AT_FUNC_POST_FILE_ARGS        , mode
+# include "at-func.c"
+# undef AT_FUNC_NAME
+# undef AT_FUNC_F1
+# undef AT_FUNC_POST_FILE_PARAM_DECLS
+# undef AT_FUNC_POST_FILE_ARGS
+
+/* Create a file system node FILE relative to directory FD, with
+   access permissions and file type in MODE, and device type in DEV.
+   Usually, non-root applications can only create named fifos, with
+   DEV set to 0.  If possible, create the node without changing the
+   working directory.  Otherwise, resort to using save_cwd/fchdir,
+   then mknod/restore_cwd.  If either the save_cwd or the restore_cwd
+   fails, then give a diagnostic and exit nonzero.  */
+
+# define AT_FUNC_NAME mknodat
+# define AT_FUNC_F1 mknod
+# define AT_FUNC_POST_FILE_PARAM_DECLS , mode_t mode, dev_t dev
+# define AT_FUNC_POST_FILE_ARGS        , mode, dev
+# include "at-func.c"
+# undef AT_FUNC_NAME
+# undef AT_FUNC_F1
+# undef AT_FUNC_POST_FILE_PARAM_DECLS
+# undef AT_FUNC_POST_FILE_ARGS
+
+#endif /* HAVE_MKFIFO */