# Dpkg::Path - some common path handling functions - perldoc - [phpMan]

## NAME
    [Dpkg::Path](https://www.chedong.com/phpMan.php/perldoc/Dpkg%3A%3APath/markdown) - some common path handling functions

## DESCRIPTION
    It provides some functions to handle various path.

## FUNCTIONS
### get_pkg_root_dir
            This function will scan upwards the hierarchy of directory to find out the directory
            which contains the "DEBIAN" sub-directory and it will return its path. This directory is
            the root directory of a package being built.

            If no DEBIAN subdirectory is found, it will return undef.

### relative_to_pkg_root
            Returns the filename relative to get_pkg_root_dir($file).

### guess_pkg_root_dir
            This function tries to guess the root directory of the package build tree. It will first
            use get_pkg_root_dir(), but it will fallback to a more imprecise check: namely it will
            use the parent directory that is a sub-directory of the debian directory.

            It can still return undef if a file outside of the debian sub-directory is provided.

### check_files_are_the_same
            This function verifies that both files are the same by checking that the device numbers
            and the inode numbers returned by stat()/lstat() are the same. If $resolve_symlink is
            true then stat() is used, otherwise lstat() is used.

### canonpath
            This function returns a cleaned path. It simplifies double //, and remove /./ and /../
            intelligently. For /../ it simplifies the path only if the previous element is not a
            symlink. Thus it should only be used on real filenames.

    $newpath = resolve_symlink($symlink)
            Return the filename of the file pointed by the symlink. The new name is canonicalized by
            canonpath().

### check_directory_traversal
            This function verifies that the directory $dir does not contain any symlink that goes
            beyond $basedir (which should be either equal or a parent of $dir).

    $cmdpath = find_command($command)
            Return the path of the command if defined and available on an absolute or relative path
            or on the $PATH, undef otherwise.

    $control_file = get_control_path($pkg, $filetype)
            Return the path of the control file of type $filetype for the given package.

    @control_files = get_control_path($pkg)
            Return the path of all available control files for the given package.

    $file = find_build_file($basename)
            Selects the right variant of the given file: the arch-specific variant
            ("$basename.$arch") has priority over the OS-specific variant ("$basename.$os") which
            has priority over the default variant ("$basename"). If none of the files exists, then
            it returns undef.

    @files = find_build_file($basename)
            Return the available variants of the given file. Returns an empty list if none of the
            files exists.

## CHANGES
  Version 1.05 (dpkg 1.20.4)
    New function: check_directory_traversal().

  Version 1.04 (dpkg 1.17.11)
    Update semantics: find_command() now handles an empty or undef argument.

  Version 1.03 (dpkg 1.16.1)
    New function: find_build_file()

  Version 1.02 (dpkg 1.16.0)
    New function: get_control_path()

  Version 1.01 (dpkg 1.15.8)
    New function: find_command()

  Version 1.00 (dpkg 1.15.6)
    Mark the module as public.