From: nobu@...
Date: 2017-05-22T07:49:24+00:00
Subject: [ruby-core:81328] [Ruby trunk Feature#13568] File#path for	O_TMPFILE fds are unmeaning

Issue #13568 has been updated by nobu (Nobuyoshi Nakada).


shyouhei (Shyouhei Urabe) wrote:
> nobu (Nobuyoshi Nakada) wrote:
> > A correction; The method which `open` calls is `to_path`, not `path`.
> > These are different.
> 
> Yes, I'm talking about `File#path`.  Situations like [ruby-core:81167](#change-64819) is in my mind.  `#to_path` is a separate issue.

`File#path` is not relevant to that situation at all.
`Digest.file` just opens the argument, and `open` calls `to_path` method on it to implicit conversion.

```sh
$ ruby -rdigest -e 'obj = Object.new; def obj.path;raise "path!"; end; Digest::MD5.file(obj)'
Traceback (most recent call last):
	4: from -e:1:in `<main>'
	3: from /opt/local/lib/ruby/2.5.0/digest.rb:35:in `file'
	2: from /opt/local/lib/ruby/2.5.0/digest.rb:50:in `file'
	1: from /opt/local/lib/ruby/2.5.0/digest.rb:50:in `open'
/opt/local/lib/ruby/2.5.0/digest.rb:50:in `initialize': no implicit conversion of Object into String (TypeError)
```
```sh
$ ruby -rdigest -e 'obj = Object.new; def obj.to_path;raise "to_path!"; end; Digest::MD5.file(obj)'
Traceback (most recent call last):
	5: from -e:1:in `<main>'
	4: from /opt/local/lib/ruby/2.5.0/digest.rb:35:in `file'
	3: from /opt/local/lib/ruby/2.5.0/digest.rb:50:in `file'
	2: from /opt/local/lib/ruby/2.5.0/digest.rb:50:in `open'
	1: from /opt/local/lib/ruby/2.5.0/digest.rb:50:in `initialize'
-e:1:in `to_path': to_path! (RuntimeError)
```

> > > Do you think `nil` is better?  I think nonexistent path is far more descriptive.
> > 
> > The write mode problem is a matter.
> > It would silently (and wrongly) success to write.
> 
> What about adding a slash then? like:
> 
> ```
> irb(main):001:0> open("/tmp/#165106976 (deleted / nonexistent)", "w")
> Errno::ENOENT: No such file or directory @ rb_sysopen - /tmp/#165106976 (deleted / nonexistent)
>         from (irb):1:in `initialize'
>         from (irb):1:in `open'
> ```

A dedicated exception such as "Unnamed temporary file in some path" from `to_path` would be more descriptive and better, I think.

> > I think that `File#to_path` should raise if the path dost not exist, but untouch `File#path`.
> 
> For `#to_path`, go to #13576.  This issue is about `#path`, and I think adding description is the best known solution; leave it untouched does not save anything.

I think this issue is false assertion at the first.


----------------------------------------
Feature #13568: File#path for O_TMPFILE fds are unmeaning
https://bugs.ruby-lang.org/issues/13568#change-65018

* Author: sorah (Sorah Fukumori)
* Status: Assigned
* Priority: Normal
* Assignee: sorah (Sorah Fukumori)
* Target version: 
----------------------------------------
By using File::TMPFILE (O_TMPFILE) allows us to create a file without directory entries.

While open(2) with O_TMPFILE don't create a file without directory entries, it still requires a directory name to determine a file system to create a file.

Current Ruby implementation holds such directory names in fptr->pathv and retrievable via File#path.
But such paths are useless and may raise errors. For example, some code [1] checks File#path availability then when available, it attempts to use the path to open a file in different fd, finally raises Errno::EISDIR.

This patch changes File#path (fptr->pathv) not to return String if a fd is opened with O_TMPFILE.

[1]: https://github.com/aws/aws-sdk-ruby/blob/v2.9.17/aws-sdk-core/lib/aws-sdk-core/checksums.rb#L15

---Files--------------------------------
tmpfile-path.patch (1.96 KB)


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