Implement cp

[GrayJack]

This is a tracking issue for the cp util.

Required options and flags in the POSIX standard:

• [ ] f (long: force)
• [ ] H (long: ¹)
• [ ] i (long: interactive)
• [ ] L (long: dereference)
• [ ] P (long: no-dereference)
• [ ] p (long: preserve)
• [ ] R (long: recursive-compat)

Required extension options and flags:

• [ ] r (long: recursive)

Notes: ¹ : Long name not defined on other implementation of this utility. Implementer must choose a long name. ² : Short name (one letter) not defined on other implementation of this utility. Implementer must choose. a short name

References

POSIX standard text

Unresolved questions:

None yet

History

[kegesch]

I will start with this.

[GrayJack]

Nice, have fun :smile:

[kegesch]

@GrayJack i ran into a problem here. Maybe you know how to solve it. cp -p -R symlink should copy a symlink and preserve its metadata. But apparently there is no way in Rust to copy a symlink. You can only create one. But also you can not set a file's metadata, at least i could not find any way to do so. Do you have an idea?

[GrayJack]

I have to look into that, never done it

[GrayJack]

How do you preserve the metadata on the other types of file?

[kegesch]

fs::copy() copies a file with metadata. And to not preserve it i use io::copy(). For dirs i have the same problem as with symlinks. There is a function in fs to set permissions but i found nothing about modified, creation date etc.

[GrayJack]

Did you found out any more info on how to do this?

[GrayJack]

Aha!!! Found it, to preserve attributes of a link you have to hardlink the files

So, if you want to copy a symlink, you have to hardlink the link to another path, and hardlink will preserve the attributes

fs::hard_link() function does that

[kegesch]

Yes, but a hardlink is not a symlink if i understood correctly.

[GrayJack]

Yes, but all code that I saw (FreeBSD, NetBSD and uutils) does that when preserving a copy a symlink preserving metadata