Perl 对以目录结尾的路径使用catfile时存在危险？_Perl_Directory Structure

Perl 对以目录结尾的路径使用catfile时存在危险？

perl

Perl 对以目录结尾的路径使用catfile时存在危险？,perl,directory-structure,Perl,Directory Structure,该模块提供了一种创建跨操作系统有效路径的方法。正如人们所期望的那样： use strict; use warnings; use File::Spec; my $file = 'ghi.xml'; my $path = File::Spec->catfile(('abc', 'def'), $file); print $path; # Windows: abc/def/ghi.xml 还有一种方法catdir，它将生成一个目录，而不是文件的路径我的问题是，我事先不知道$file是文

该模块提供了一种创建跨操作系统有效路径的方法。正如人们所期望的那样：

use strict;
use warnings;

use File::Spec;

my $file = 'ghi.xml';
my $path = File::Spec->catfile(('abc', 'def'), $file);
print $path;
# Windows: abc/def/ghi.xml

还有一种方法

catdir

，它将生成一个目录，而不是文件的路径

我的问题是，我事先不知道

$file

是文件名还是目录名。就我所做的测试而言，使用dirname时，结果仍然正确，例如：

use strict;
use warnings;

use File::Spec;

my $file = 'ghi';
my $path = File::Spec->catfile(('abc', 'def'), $file);
print $path;
# Windows: abc/def/ghi

但我想知道这是否会引起问题。我假设是，因为我不明白为什么模块的创建者会为相同的功能构建两个接口。但是，我在文档中找不到任何进一步的解释

使用

catfile

创建文件和目录的路径是否安全？如果没有，注意事项是什么？

catdir和

catfile

之间的差异通常很小（取决于使用的操作系统）。在UNIX上，
catfile
对目录元素执行
catdir
操作（例如减去最后一个（文件）部分），然后追加文件部分。
catdir
执行一些路径清理逻辑。在windows平台上，差异甚至更小
你可以自己检查一下
主要的是：这些例程不做任何文件系统访问，只是做一些逻辑路径清理

备选方案：
如果您不关心其他类似UNIX的操作系统（如Linux、FreeBSD、Mac OS X等）和Windows，我个人建议您使用该模块。从它的文件：
此模块提供了一个用于处理文件的小型快速实用程序路径。它比File:：Spec更易于使用，并且提供了简单的从其他几个核心文件处理模块访问功能。信息技术旨在比CPAN上的许多备选方案更小更快，而帮助人们以一致和较少的方式做许多常见的事情容易出错的方法
Path:：Tiny不尝试为任何东西工作，除了类Unix和 Win32平台
IMHO-它是CPAN上最好的模块之一-真正的宝藏。例如，对于路径创建，您应该使用
child
方法-同样来自文档：
返回相对于原始对象的新路径：：微小对象。像
catfile
或
catdir
来自File:：Spec，但不关心文件或目录
除上述内容外，该模块还提供了对文件内容的轻松访问（还提供了unicode处理）和所有常用的“路径”操作。缺点：不幸的是，它不是核心模块，例如，您需要从CPAN安装它
编辑对目录使用
catfile
安全吗？我说：是的（但也许一些专家会知道一些其他或更多的东西）。在unix上

catdir
调用
canopath
（它执行一些逻辑路径清理）

catfile
调用
canopath
两次，一次用于文件部分，一次用于目录（如果提供），并将两个结果连接起来。连接可能会产生一些奇怪的路径，但它们通常是无害的

在Windows上，差异甚至更小，两者都将调用路径清理例程
演示-以下脚本将生成许多不同部分的组合，并将使用
catdir
和
catfile
（甚至还有
Path:：Tiny的两个变体）它打印了一个很长的结果。正如您在下面看到的，所有路径对于目录和文件都是安全的，只是来自catfile 的一些路径并不“好” 这两个“Path:：Tiny”结果都清晰一致。相反，catfile 和catdir 将允许使用未定义的部分（演示中未显示）-即使在这种错误的参数中也会产生一些结果，如果您将未定义或空字符串传递给其子方法，Path:：Tiny将失效 first second catdir catfile path-child path-list ------------------------------------------------------------------------------------------------ first second first/second first/second first/second first/second first / first first// first first first /second first/second first//second first/second first/second first /second/ first/second first//second first/second first/second first /second// first/second first//second first/second first/second first // first first// first first first //second first/second first//second first/second first/second first //second/ first/second first//second first/second first/second first //second// first/second first//second first/second first/second first /./ first first// first first first /./second first/second first//second first/second first/second first /second/./ first/second first//second first/second first/second / second /second /second /second /second / / / // / / / /second /second //second /second /second / /second/ /second //second /second /second / /second// /second //second /second /second / // / // / / / //second /second //second /second /second / //second/ /second //second /second /second / //second// /second //second /second /second / /./ / // / / / /./second /second //second /second /second / /second/./ /second //second /second /second /first second /first/second /first/second /first/second /first/second /first / /first /first// /first /first /first /second /first/second /first//second /first/second /first/second /first /second/ /first/second /first//second /first/second /first/second /first /second// /first/second /first//second /first/second /first/second /first // /first /first// /first /first /first //second /first/second /first//second /first/second /first/second /first //second/ /first/second /first//second /first/second /first/second /first //second// /first/second /first//second /first/second /first/second /first /./ /first /first// /first /first /first /./second /first/second /first//second /first/second /first/second /first /second/./ /first/second /first//second /first/second /first/second /first/ second /first/second /first/second /first/second /first/second /first/ / /first /first// /first /first /first/ /second /first/second /first//second /first/second /first/second /first/ /second/ /first/second /first//second /first/second /first/second /first/ /second// /first/second /first//second /first/second /first/second /first/ // /first /first// /first /first /first/ //second /first/second /first//second /first/second /first/second /first/ //second/ /first/second /first//second /first/second /first/second /first/ //second// /first/second /first//second /first/second /first/second /first/ /./ /first /first// /first /first /first/ /./second /first/second /first//second /first/second /first/second /first/ /second/./ /first/second /first//second /first/second /first/second /first// second /first/second /first/second /first/second /first/second /first// / /first /first// /first /first /first// /second /first/second /first//second /first/second /first/second /first// /second/ /first/second /first//second /first/second /first/second /first// /second// /first/second /first//second /first/second /first/second /first// // /first /first// /first /first /first// //second /first/second /first//second /first/second /first/second /first// //second/ /first/second /first//second /first/second /first/second /first// //second// /first/second /first//second /first/second /first/second /first// /./ /first /first// /first /first /first// /./second /first/second /first//second /first/second /first/second /first// /second/./ /first/second /first//second /first/second /first/second // second /second /second /second /second // / / // / / // /second /second //second /second /second // /second/ /second //second /second /second // /second// /second //second /second /second // // / // / / // //second /second //second /second /second // //second/ /second //second /second /second // //second// /second //second /second /second // /./ / // / / // /./second /second //second /second /second // /second/./ /second //second /second /second //first second /first/second /first/second /first/second /first/second //first / /first /first// /first /first //first /second /first/second /first//second /first/second /first/second //first /second/ /first/second /first//second /first/second /first/second //first /second// /first/second /first//second /first/second /first/second //first // /first /first// /first /first //first //second /first/second /first//second /first/second /first/second //first //second/ /first/second /first//second /first/second /first/second //first //second// /first/second /first//second /first/second /first/second //first /./ /first /first// /first /first //first /./second /first/second /first//second /first/second /first/second //first /second/./ /first/second /first//second /first/second /first/second //first/ second /first/second /first/second /first/second /first/second //first/ / /first /first// /first /first //first/ /second /first/second /first//second /first/second /first/second //first/ /second/ /first/second /first//second /first/second /first/second //first/ /second// /first/second /first//second /first/second /first/second //first/ // /first /first// /first /first //first/ //second /first/second /first//second /first/second /first/second //first/ //second/ /first/second /first//second /first/second /first/second //first/ //second// /first/second /first//second /first/second /first/second //first/ /./ /first /first// /first /first //first/ /./second /first/second /first//second /first/second /first/second //first/ /second/./ /first/second /first//second /first/second /first/second //first// second /first/second /first/second /first/second /first/second //first// / /first /first// /first /first //first// /second /first/second /first//second /first/second /first/second //first// /second/ /first/second /first//second /first/second /first/second //first// /second// /first/second /first//second /first/second /first/second //first// // /first /first// /first /first //first// //second /first/second /first//second /first/second /first/second //first// //second/ /first/second /first//second /first/second /first/second //first// //second// /first/second /first//second /first/second /first/second //first// /./ /first /first// /first /first //first// /./second /first/second /first//second /first/second /first/second //first// /second/./ /first/second /first//second /first/second /first/second /./ second /second /second /second /second /./ / / // / / /./ /second /second //second /second /second /./ /second/ /second //second /second /second /./ /second// /second //second /second /second /./ // / // / / /./ //second /second //second /second /second /./ //second/ /second //second /second /second /./ //second// /second //second /second /second /./ /./ / // / / /./ /./second /second //second /second /second /./ /second/./ /second //second /second /second /./first second /first/second /first/second /first/second /first/second /./first / /first /first// /first /first /./first /second /first/second /first//second /first/second /first/second /./first /second/ /first/second /first//second /first/second /first/second /./first /second// /first/second /first//second /first/second /first/second /./first // /first /first// /first /first /./first //second /first/second /first//second /first/second /first/second /./first //second/ /first/second /first//second /first/second /first/second /./first //second// /first/second /first//second /first/second /first/second /./first /./ /first /first// /first /first /./first /./second /first/second /first//second /first/second /first/second /./first /second/./ /first/second /first//second /first/second /first/second /first/./ second /first/second /first/second /first/second /first/second /first/./ / /first /first// /first /first /first/./ /second /first/second /first//second /first/second /first/second /first/./ /second/ /first/second /first//second /first/second /first/second /first/./ /second// /first/second /first//second /first/second /first/second /first/./ // /first /first// /first /first /first/./ //second /first/second /first//second /first/second /first/second /first/./ //second/ /first/second /first//second /first/second /first/second /first/./ //second// /first/second /first//second /first/second /first/second /first/./ /./ /first /first// /first /first /first/./ /./second /first/second /first//second /first/second /first/second /first/./ /second/./ /first/second /first//second /first/second /first/second 在我看来是一样的，只是catdir的早期返回。@你正在查看文件：：Spec：：Win32 ，OP没有说明他们使用的是什么平台。你怎么能不知道你是在处理文件还是目录呢？@Borodin，例如，在执行readdir时。要检查-d ，我需要完整的路径（即将读取项与读取目录连接起来），因此我事先不知道它们是什么。（这只是一个例子，不是我的实际情况。）这可能会对VM和其他“外来”系统产生影响。如果您只处理Unix ish系统和Windows，您可以使用'abc/def/ghi'并完成它。因此，正如Melpomene在OP上的评论，我可能在只涉及基于Unix的系统和Windows时是安全的？谢谢你提供路径：：Tiny的链接，我来看看。任何理由（除了手头的主题）都认为它比File:：Spec？@BramVanroy-imho中的功能更好，它是安全的，但是请参见编辑。 use strict; use warnings; use File::Spec::Functions; use Path::Tiny; my @parts = qw(x / /x /x/ /x// // //x //x/ //x// /./ /./x /x/./ ); my $cwidth=16; print pr(qw(first second catdir catfile path-child path-list)), "\n"; print '-' x ($cwidth*6),"\n"; for my $first (map { s/x/first/r } @parts) { for my $second ( map { s/x/second/r } @parts) { print pr( $first, $second, catdir($first,$second), catfile($first,$second), path($first)->child($second), path($first,$second), ), "\n"; } } sub pr { my $str; $str .= sprintf "%-${cwidth}s",$_ for @_; return $str; } first second catdir catfile path-child path-list ------------------------------------------------------------------------------------------------ first second first/second first/second first/second first/second first / first first// first first first /second first/second first//second first/second first/second first /second/ first/second first//second first/second first/second first /second// first/second first//second first/second first/second first // first first// first first first //second first/second first//second first/second first/second first //second/ first/second first//second first/second first/second first //second// first/second first//second first/second first/second first /./ first first// first first first /./second first/second first//second first/second first/second first /second/./ first/second first//second first/second first/second / second /second /second /second /second / / / // / / / /second /second //second /second /second / /second/ /second //second /second /second / /second// /second //second /second /second / // / // / / / //second /second //second /second /second / //second/ /second //second /second /second / //second// /second //second /second /second / /./ / // / / / /./second /second //second /second /second / /second/./ /second //second /second /second /first second /first/second /first/second /first/second /first/second /first / /first /first// /first /first /first /second /first/second /first//second /first/second /first/second /first /second/ /first/second /first//second /first/second /first/second /first /second// /first/second /first//second /first/second /first/second /first // /first /first// /first /first /first //second /first/second /first//second /first/second /first/second /first //second/ /first/second /first//second /first/second /first/second /first //second// /first/second /first//second /first/second /first/second /first /./ /first /first// /first /first /first /./second /first/second /first//second /first/second /first/second /first /second/./ /first/second /first//second /first/second /first/second /first/ second /first/second /first/second /first/second /first/second /first/ / /first /first// /first /first /first/ /second /first/second /first//second /first/second /first/second /first/ /second/ /first/second /first//second /first/second /first/second /first/ /second// /first/second /first//second /first/second /first/second /first/ // /first /first// /first /first /first/ //second /first/second /first//second /first/second /first/second /first/ //second/ /first/second /first//second /first/second /first/second /first/ //second// /first/second /first//second /first/second /first/second /first/ /./ /first /first// /first /first /first/ /./second /first/second /first//second /first/second /first/second /first/ /second/./ /first/second /first//second /first/second /first/second /first// second /first/second /first/second /first/second /first/second /first// / /first /first// /first /first /first// /second /first/second /first//second /first/second /first/second /first// /second/ /first/second /first//second /first/second /first/second /first// /second// /first/second /first//second /first/second /first/second /first// // /first /first// /first /first /first// //second /first/second /first//second /first/second /first/second /first// //second/ /first/second /first//second /first/second /first/second /first// //second// /first/second /first//second /first/second /first/second /first// /./ /first /first// /first /first /first// /./second /first/second /first//second /first/second /first/second /first// /second/./ /first/second /first//second /first/second /first/second // second /second /second /second /second // / / // / / // /second /second //second /second /second // /second/ /second //second /second /second // /second// /second //second /second /second // // / // / / // //second /second //second /second /second // //second/ /second //second /second /second // //second// /second //second /second /second // /./ / // / / // /./second /second //second /second /second // /second/./ /second //second /second /second //first second /first/second /first/second /first/second /first/second //first / /first /first// /first /first //first /second /first/second /first//second /first/second /first/second //first /second/ /first/second /first//second /first/second /first/second //first /second// /first/second /first//second /first/second /first/second //first // /first /first// /first /first //first //second /first/second /first//second /first/second /first/second //first //second/ /first/second /first//second /first/second /first/second //first //second// /first/second /first//second /first/second /first/second //first /./ /first /first// /first /first //first /./second /first/second /first//second /first/second /first/second //first /second/./ /first/second /first//second /first/second /first/second //first/ second /first/second /first/second /first/second /first/second //first/ / /first /first// /first /first //first/ /second /first/second /first//second /first/second /first/second //first/ /second/ /first/second /first//second /first/second /first/second //first/ /second// /first/second /first//second /first/second /first/second //first/ // /first /first// /first /first //first/ //second /first/second /first//second /first/second /first/second //first/ //second/ /first/second /first//second /first/second /first/second //first/ //second// /first/second /first//second /first/second /first/second //first/ /./ /first /first// /first /first //first/ /./second /first/second /first//second /first/second /first/second //first/ /second/./ /first/second /first//second /first/second /first/second //first// second /first/second /first/second /first/second /first/second //first// / /first /first// /first /first //first// /second /first/second /first//second /first/second /first/second //first// /second/ /first/second /first//second /first/second /first/second //first// /second// /first/second /first//second /first/second /first/second //first// // /first /first// /first /first //first// //second /first/second /first//second /first/second /first/second //first// //second/ /first/second /first//second /first/second /first/second //first// //second// /first/second /first//second /first/second /first/second //first// /./ /first /first// /first /first //first// /./second /first/second /first//second /first/second /first/second //first// /second/./ /first/second /first//second /first/second /first/second /./ second /second /second /second /second /./ / / // / / /./ /second /second //second /second /second /./ /second/ /second //second /second /second /./ /second// /second //second /second /second /./ // / // / / /./ //second /second //second /second /second /./ //second/ /second //second /second /second /./ //second// /second //second /second /second /./ /./ / // / / /./ /./second /second //second /second /second /./ /second/./ /second //second /second /second /./first second /first/second /first/second /first/second /first/second /./first / /first /first// /first /first /./first /second /first/second /first//second /first/second /first/second /./first /second/ /first/second /first//second /first/second /first/second /./first /second// /first/second /first//second /first/second /first/second /./first // /first /first// /first /first /./first //second /first/second /first//second /first/second /first/second /./first //second/ /first/second /first//second /first/second /first/second /./first //second// /first/second /first//second /first/second /first/second /./first /./ /first /first// /first /first /./first /./second /first/second /first//second /first/second /first/second /./first /second/./ /first/second /first//second /first/second /first/second /first/./ second /first/second /first/second /first/second /first/second /first/./ / /first /first// /first /first /first/./ /second /first/second /first//second /first/second /first/second /first/./ /second/ /first/second /first//second /first/second /first/second /first/./ /second// /first/second /first//second /first/second /first/second /first/./ // /first /first// /first /first /first/./ //second /first/second /first//second /first/second /first/second /first/./ //second/ /first/second /first//second /first/second /first/second /first/./ //second// /first/second /first//second /first/second /first/second /first/./ /./ /first /first// /first /first /first/./ /./second /first/second /first//second /first/second /first/second /first/./ /second/./ /first/second /first//second /first/second /first/second