* io/sys/stat.h [__USE_GNU]: Declare fchmodat.

	* io/fchmodat.c: New file.
	* io/Makefile (routines): Add fchmodat.
	* io/Versions (libc: GLIBC_2.4): Likewise.
	* sysdeps/unix/sysv/linux/fchmodat.c: New file.
	* io/tst-fchmodat.c: New file.
	* io/Makefile (tests): Add it.

1 files changed, 87 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/fchmodat.c b/sysdeps/unix/sysv/linux/fchmodat.c
new file mode 100644
index 0000000000..de35e4376f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/fchmodat.c
@@ -0,0 +1,87 @@
+/* Change the protections of file relative to open directory.  Linux version.
+   Copyright (C) 2006 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <alloca.h>
+#include <sysdep.h>
+
+int
+fchmodat (fd, file, mode, flag)
+     int fd;
+     const char *file;
+     mode_t mode;
+     int flag;
+{
+  if (flag & ~AT_SYMLINK_NOFOLLOW)
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+#ifndef __NR_lchmod		/* Linux so far has no lchmod syscall.  */
+  if (flag & AT_SYMLINK_NOFOLLOW)
+    {
+      __set_errno (ENOTSUP);
+      return -1;
+    }
+#endif
+
+  char *buf = NULL;
+
+  if (fd != AT_FDCWD && file[0] != '/')
+    {
+      size_t filelen = strlen (file);
+      static const char procfd[] = "/proc/self/fd/%d/%s";
+      /* Buffer for the path name we are going to use.  It consists of
+	 - the string /proc/self/fd/
+	 - the file descriptor number
+	 - the file name provided.
+	 The final NUL is included in the sizeof.   A bit of overhead
+	 due to the format elements compensates for possible negative
+	 numbers.  */
+      size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
+      buf = alloca (buflen);
+
+      __snprintf (buf, buflen, procfd, fd, file);
+      file = buf;
+    }
+
+  int result;
+  INTERNAL_SYSCALL_DECL (err);
+
+#ifdef __NR_lchmod
+  if (flag & AT_SYMLINK_NOFOLLOW)
+    result = INTERNAL_SYSCALL (lchmod, err, 2, file, mode);
+  else
+#endif
+    result = INTERNAL_SYSCALL (chmod, err, 2, file, mode);
+
+  if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 0))
+    {
+      __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
+      result = -1;
+    }
+
+  return result;
+}