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/fs/set_permissions_impl.rs (line 24)

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

    // 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 Errno::from_io_error(&err) {
            Some(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 Errno::from_io_error(&err) {
            Some(Errno::ACCESS) | Some(Errno::ISDIR) => (),
            _ => return Err(err),
        },
    }

    // If neither of those worked, we're out of luck.
    Err(Errno::NOTSUP.into())
}

src/rustix/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 Errno::from_io_error(&err) {
            Some(Errno::ACCESS) | Some(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 Errno::from_io_error(&err) {
            Some(Errno::ACCESS) => (),
            _ => return Err(err),
        },
    }

    // It's not possible to do anything else with generic POSIX. Plain
    // `utimensat` has two options:
    //  - Follow symlinks, which would open up a race in which a concurrent
    //    modification of the symlink could point outside the sandbox and we
    //    wouldn't be able to detect it, or
    //  - Don't follow symlinks, which would modify the timestamp of the symlink
    //    instead of the file we're trying to get to.
    //
    // So neither does what we need.
    Err(Errno::NOTSUP.into())
}