[pbs-devel] applied: [PATCH proxmox v2 1/1] partially fix #2915: proxmox-sys: scandir: stat if file_type is unknown

[Wolfgang Bumiller <w.bumiller@proxmox.com>]

applied

On Tue, Jun 28, 2022 at 03:15:13PM +0200, Dominik Csapak wrote:
> when using readdir/getdents the file type might be 'DT_UNKNOWN'
> (depending on the filesystem). Do a fstatat in that case to
> get the file type. Since maybe the callback wants to do
> a stat anyway, pass it there (if done)
> 
> adds two new helpers:
> 'file_type_from_file_stat': uses a FileStat struct to get the file type
> 'get_file_type': calls fstatat to determine the file_type
> 
> Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
> ---
>  proxmox-sys/src/fs/read_dir.rs | 34 ++++++++++++++++++++++++++++++++--
>  1 file changed, 32 insertions(+), 2 deletions(-)
> 
> diff --git a/proxmox-sys/src/fs/read_dir.rs b/proxmox-sys/src/fs/read_dir.rs
> index f687748..8c0c5a0 100644
> --- a/proxmox-sys/src/fs/read_dir.rs
> +++ b/proxmox-sys/src/fs/read_dir.rs
> @@ -2,7 +2,7 @@ use std::borrow::{Borrow, BorrowMut};
>  use std::ops::{Deref, DerefMut};
>  use std::os::unix::io::{AsRawFd, RawFd};
>  
> -use anyhow::{bail, format_err, Error};
> +use anyhow::{format_err, Error};
>  use nix::dir;
>  use nix::dir::Dir;
>  use nix::fcntl::OFlag;
> @@ -148,7 +148,7 @@ where
>          let entry = entry?;
>          let file_type = match entry.file_type() {
>              Some(file_type) => file_type,
> -            None => bail!("unable to detect file type"),
> +            None => get_file_type(entry.parent_fd(), entry.file_name())?,
>          };
>  
>          callback(
> @@ -321,3 +321,33 @@ fn do_lock_dir_noblock(
>  
>      Ok(handle)
>  }
> +
> +/// extracts [`nix::dir::Type`] from a [`nix::sys::stat::FileStat`] if possible
> +pub fn file_type_from_file_stat(stat: &nix::sys::stat::FileStat) -> Option<nix::dir::Type> {
> +    use nix::dir::Type;
> +
> +    // mask out all unnecessary bits
> +    Some(match stat.st_mode & libc::S_IFMT {
> +        libc::S_IFSOCK => Type::Socket,
> +        libc::S_IFLNK => Type::Symlink,
> +        libc::S_IFREG => Type::File,
> +        libc::S_IFBLK => Type::BlockDevice,
> +        libc::S_IFDIR => Type::Directory,
> +        libc::S_IFCHR => Type::CharacterDevice,
> +        libc::S_IFIFO => Type::Fifo,
> +        _ => return None,
> +    })
> +}
> +
> +/// Returns the file type of the `path` in the `parent_fd`
> +///
> +/// calls [`nix::sys::stat::fstatat`] to determine it
> +pub fn get_file_type<P: ?Sized + nix::NixPath>(
> +    parent_fd: RawFd,
> +    path: &P,
> +) -> Result<nix::dir::Type, Error> {
> +    let stat = nix::sys::stat::fstatat(parent_fd, path, nix::fcntl::AtFlags::AT_SYMLINK_NOFOLLOW)?;
> +    let file_type =
> +        file_type_from_file_stat(&stat).ok_or_else(|| format_err!("unable to detect file type"))?;
> +    Ok(file_type)
> +}
> -- 
> 2.30.2