Function cap_primitives::fs::open

pub fn open(start: &File, path: &Path, options: &OpenOptions) -> Result<File>

Perform an openat-like operation, ensuring that the resolution of the path never escapes the directory tree rooted at start.

Examples found in repository

src/fs/open_dir.rs (line 16)

pub fn open_dir(start: &fs::File, path: &Path) -> io::Result<fs::File> {
    open(start, path, &dir_options())
}

/// Like `open_dir`, but additionally request the ability to read the directory
/// entries.
#[cfg(not(windows))]
#[inline]
pub(crate) fn open_dir_for_reading(
    start: &fs::File,
    path: &Path,
    follow: FollowSymlinks,
) -> io::Result<fs::File> {
    open(start, path, readdir_options().follow(follow))
}

/// Similar to `open_dir`, but fails if the path names a symlink.
#[inline]
pub fn open_dir_nofollow(start: &fs::File, path: &Path) -> io::Result<fs::File> {
    open(start, path, dir_options().follow(FollowSymlinks::No))
}

src/rustix/fs/copy_impl.rs (line 17)

fn open_from(start: &fs::File, path: &Path) -> io::Result<(fs::File, fs::Metadata)> {
    let reader = open(start, path, OpenOptions::new().read(true))?;
    let metadata = reader.metadata()?;
    if !metadata.is_file() {
        return Err(io::Error::new(
            io::ErrorKind::InvalidInput,
            "the source path is not an existing regular file",
        ));
    }
    Ok((reader, metadata))
}

#[cfg(not(target_os = "wasi"))]
fn open_to_and_set_permissions(
    start: &fs::File,
    path: &Path,
    reader_metadata: fs::Metadata,
) -> io::Result<(fs::File, fs::Metadata)> {
    use rustix::fs::OpenOptionsExt;
    use std::os::unix::fs::PermissionsExt;

    let perm = reader_metadata.permissions();
    let writer = open(
        start,
        path,
        OpenOptions::new()
            // create the file with the correct mode right away
            .mode(perm.mode())
            .write(true)
            .create(true)
            .truncate(true),
    )?;
    let writer_metadata = writer.metadata()?;
    if writer_metadata.is_file() {
        // Set the correct file permissions, in case the file already existed.
        // Don't set the permissions on already existing non-files like
        // pipes/FIFOs or device nodes.
        writer.set_permissions(perm)?;
    }
    Ok((writer, writer_metadata))
}

src/rustix/linux/fs/procfs.rs (lines 39-45)

pub(crate) fn set_permissions_through_proc_self_fd(
    start: &fs::File,
    path: &Path,
    perm: fs::Permissions,
) -> io::Result<()> {
    let opath = open(
        start,
        path,
        OpenOptions::new()
            .read(true)
            .custom_flags(OFlags::PATH.bits() as i32),
    )?;

    let dirfd = proc_self_fd()?;
    let mode = Mode::from_bits(perm.mode() as RawMode).ok_or_else(errors::invalid_flags)?;
    Ok(chmodat(&dirfd, DecInt::from_fd(&opath), mode)?)
}

pub(crate) fn set_times_through_proc_self_fd(
    start: &fs::File,
    path: &Path,
    atime: Option<SystemTimeSpec>,
    mtime: Option<SystemTimeSpec>,
) -> io::Result<()> {
    let opath = open(
        start,
        path,
        OpenOptions::new()
            .read(true)
            .custom_flags(OFlags::PATH.bits() as i32),
    )?;

    // Don't pass `AT_SYMLINK_NOFOLLOW`, because we do actually want to follow
    // the first symlink. We don't want to follow any subsequent symlinks, but
    // omitting `O_NOFOLLOW` above ensures that the destination of the link
    // isn't a symlink.
    set_times_follow_unchecked(
        proc_self_fd()?.as_fd(),
        DecInt::from_fd(&opath).as_ref(),
        atime,
        mtime,
    )
}

src/rustix/linux/fs/set_times_impl.rs (line 17)

pub(crate) fn set_times_impl(
    start: &fs::File,
    path: &Path,
    atime: Option<SystemTimeSpec>,
    mtime: Option<SystemTimeSpec>,
) -> io::Result<()> {
    // Try `futimens` with a normal handle. Normal handles need some kind of
    // access, so first try write.
    match open(start, path, OpenOptions::new().write(true)) {
        Ok(file) => {
            return fs_set_times::SetTimes::set_times(
                &file,
                atime.map(SystemTimeSpec::into_std),
                mtime.map(SystemTimeSpec::into_std),
            )
        }
        Err(err) => match rustix::io::Errno::from_io_error(&err) {
            Some(rustix::io::Errno::ACCESS) | Some(rustix::io::Errno::ISDIR) => (),
            _ => return Err(err),
        },
    }

    // Next try read.
    match open(start, path, OpenOptions::new().read(true)) {
        Ok(file) => {
            return fs_set_times::SetTimes::set_times(
                &file,
                atime.map(SystemTimeSpec::into_std),
                mtime.map(SystemTimeSpec::into_std),
            )
        }
        Err(err) => match rustix::io::Errno::from_io_error(&err) {
            Some(rustix::io::Errno::ACCESS) => (),
            _ => return Err(err),
        },
    }

    // If neither of those worked, turn to `/proc`.
    set_times_through_proc_self_fd(start, path, atime, mtime)
}

src/rustix/linux/fs/set_permissions_impl.rs (line 29)

pub(crate) fn set_permissions_impl(
    start: &fs::File,
    path: &Path,
    perm: Permissions,
) -> io::Result<()> {
    let std_perm = perm.into_std(start)?;

    // First try using `O_PATH` and doing a chmod on `/proc/self/fd/{}`
    // (`fchmod` doesn't work on `O_PATH` file descriptors).
    //
    // This may fail, due to older Linux versions not supporting `O_PATH`, or
    // due to procfs being unavailable, but if it does work, go with it, as
    // `O_PATH` tells Linux that we don't actually need to read or write the
    // file, which may avoid side effects associated with opening device files.
    let result = set_permissions_through_proc_self_fd(start, path, std_perm.clone());
    if let Ok(()) = result {
        return Ok(());
    }

    // Then try `fchmod` with a normal handle. Normal handles need some kind of
    // access, so first try read.
    match open(start, path, OpenOptions::new().read(true)) {
        Ok(file) => return set_file_permissions(&file, std_perm),
        Err(err) => match rustix::io::Errno::from_io_error(&err) {
            Some(rustix::io::Errno::ACCESS) => (),
            _ => return Err(err),
        },
    }

    // Next try write.
    match open(start, path, OpenOptions::new().write(true)) {
        Ok(file) => return set_file_permissions(&file, std_perm),
        Err(err) => match rustix::io::Errno::from_io_error(&err) {
            Some(rustix::io::Errno::ACCESS) | Some(rustix::io::Errno::ISDIR) => (),
            _ => return Err(err),
        },
    }

    // Nothing worked, so just return the original error.
    result
}