Replace two copies of readlink code with single gnulib version.

1 files changed, 67 insertions, 0 deletions

diff --git a/lib/careadlinkat.h b/lib/careadlinkat.h
new file mode 100644
index 0000000000..c5e4bcfc15
--- /dev/null
+++ b/lib/careadlinkat.h
@@ -0,0 +1,67 @@
+/* Read symbolic links into a buffer without size limitation, relative to fd.
+
+   Copyright (C) 2011 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 Paul Eggert, Bruno Haible, and Jim Meyering.  */
+
+#ifndef _GL_CAREADLINKAT_H
+
+#include <fcntl.h>
+#include <unistd.h>
+
+struct allocator;
+
+/* Assuming the current directory is FD, get the symbolic link value
+   of FILENAME as a null-terminated string and put it into a buffer.
+   If FD is AT_FDCWD, FILENAME is interpreted relative to the current
+   working directory, as in openat.
+
+   If the link is small enough to fit into BUFFER put it there.
+   BUFFER's size is BUFFER_SIZE, and BUFFER can be null
+   if BUFFER_SIZE is zero.
+
+   If the link is not small, put it into a dynamically allocated
+   buffer managed by ALLOC.  It is the caller's responsibility to free
+   the returned value if it is nonnull and is not BUFFER.
+
+   The PREADLINKAT function specifies how to read links.
+
+   If successful, return the buffer address; otherwise return NULL and
+   set errno.  */
+
+char *careadlinkat (int fd, char const *filename,
+                    char *buffer, size_t buffer_size,
+                    struct allocator const *alloc,
+                    ssize_t (*preadlinkat) (int, char const *,
+                                            char *, size_t));
+
+/* Suitable values for careadlinkat's FD and PREADLINKAT arguments,
+   when doing a plain readlink.  */
+#if HAVE_READLINKAT
+# define careadlinkatcwd readlinkat
+#else
+/* Define AT_FDCWD independently, so that the careadlinkat module does
+   not depend on the fcntl-h module.  The value does not matter, since
+   careadlinkatcwd ignores it, but we might as well use the same value
+   as fcntl-h.  */
+# ifndef AT_FDCWD
+#  define AT_FDCWD (-3041965)
+# endif
+ssize_t careadlinkatcwd (int fd, char const *filename,
+                         char *buffer, size_t buffer_size);
+#endif
+
+#endif /* _GL_CAREADLINKAT_H */