[PATCH] libc/sysdeps/linux/common/isfdtype.c: add support for isfdtype()

Anthony G. Basile basile at opensource.dyc.edu
Sun Jul 28 13:08:34 UTC 2013


From: "Anthony G. Basile" <blueness at gentoo.org>

isfdtype(int fd, int fdtype) check whether a file descriptor fd is
of type fdtype, where the types are defined in stat(2).  It is
supported in glibc and BSD, and used by utilities such as acpid.

Signed-off-by: Anthony G. Basile <blueness at gentoo.org>
---
 include/sys/socket.h                 |  1 +
 libc/sysdeps/linux/common/isfdtype.c | 43 ++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 libc/sysdeps/linux/common/isfdtype.c

diff --git a/include/sys/socket.h b/include/sys/socket.h
index 8642312..a9d5804 100644
--- a/include/sys/socket.h
+++ b/include/sys/socket.h
@@ -261,6 +261,7 @@ extern int sockatmark (int __fd) __THROW;
    returns 1 if FD is open on an object of the indicated type, 0 if not,
    or -1 for errors (setting errno).  */
 extern int isfdtype (int __fd, int __fdtype) __THROW;
+libc_hidden_proto(isfdtype)
 #endif
 
 __END_DECLS
diff --git a/libc/sysdeps/linux/common/isfdtype.c b/libc/sysdeps/linux/common/isfdtype.c
new file mode 100644
index 0000000..500b5f2
--- /dev/null
+++ b/libc/sysdeps/linux/common/isfdtype.c
@@ -0,0 +1,43 @@
+/* Determine whether descriptor has given property.
+   Copyright (C) 1996-2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library 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 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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 the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+int
+isfdtype (int fildes, int fdtype)
+{
+#ifdef __USE_MISC
+  struct stat64 st;
+  int result;
+
+  {
+    int save_error = errno;
+    result = fstat64 (fildes, &st);
+    __set_errno (save_error);
+  }
+
+  return result ?: (st.st_mode & S_IFMT) == (mode_t) fdtype;
+#else
+  __set_errno (ENOSYS);
+  return -1;
+#endif
+}
+libc_hidden_def(isfdtype)
-- 
1.8.1.5



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