exa/src/fs/file.rs
Benjamin Sago f9f7ad2230 Read setuid/setgid/sticky bits
The problem here was that we were using `metadata.permissions().mode()`, which is capped at 0o777, rather than `metadata.mode()`, which exposes every bit. With this change, we can access the higher-order permission bits, and put them in the Permissions struct.
2017-05-30 15:29:29 +01:00

481 lines
16 KiB
Rust
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//! Files, and methods and fields to access their metadata.
use std::fs;
use std::io::Error as IOError;
use std::io::Result as IOResult;
use std::os::unix::fs::{MetadataExt, PermissionsExt, FileTypeExt};
use std::path::{Path, PathBuf};
use fs::dir::Dir;
use fs::fields as f;
/// A **File** is a wrapper around one of Rust's Path objects, along with
/// associated data about the file.
///
/// Each file is definitely going to have its filename displayed at least
/// once, have its file extension extracted at least once, and have its metadata
/// information queried at least once, so it makes sense to do all this at the
/// start and hold on to all the information.
pub struct File<'dir> {
/// The filename portion of this file's path, including the extension.
///
/// This is used to compare against certain filenames (such as checking if
/// its “Makefile” or something) and to highlight only the filename in
/// colour when displaying the path.
pub name: String,
/// The files names extension, if present, extracted from the name.
///
/// This is queried many times over, so its worth caching it.
pub ext: Option<String>,
/// The path that begat this file.
///
/// Even though the file's name is extracted, the path needs to be kept
/// around, as certain operations involve looking up the file's absolute
/// location (such as the Git status, or searching for compiled files).
pub path: PathBuf,
/// A cached `metadata` call for this file.
///
/// This too is queried multiple times, and is *not* cached by the OS, as
/// it could easily change between invocations - but exa is so short-lived
/// it's better to just cache it.
pub metadata: fs::Metadata,
/// A reference to the directory that contains this file, if present.
///
/// Filenames that get passed in on the command-line directly will have no
/// parent directory reference - although they technically have one on the
/// filesystem, we'll never need to look at it, so it'll be `None`.
/// However, *directories* that get passed in will produce files that
/// contain a reference to it, which is used in certain operations (such
/// as looking up a file's Git status).
pub dir: Option<&'dir Dir>,
}
impl<'dir> File<'dir> {
/// Create a new `File` object from the given `Path`, inside the given
/// `Dir`, if appropriate.
///
/// This uses `symlink_metadata` instead of `metadata`, which doesn't
/// follow symbolic links.
pub fn from_path(path: &Path, parent: Option<&'dir Dir>) -> IOResult<File<'dir>> {
fs::symlink_metadata(path).map(|metadata| File::with_metadata(metadata, path, parent))
}
/// Create a new File object from the given metadata result, and other data.
pub fn with_metadata(metadata: fs::Metadata, path: &Path, parent: Option<&'dir Dir>) -> File<'dir> {
let filename = match path.components().next_back() {
Some(comp) => comp.as_os_str().to_string_lossy().to_string(),
None => String::new(),
};
File {
path: path.to_path_buf(),
dir: parent,
metadata: metadata,
ext: ext(path),
name: filename,
}
}
/// Whether this file is a directory on the filesystem.
pub fn is_directory(&self) -> bool {
self.metadata.is_dir()
}
/// If this file is a directory on the filesystem, then clone its
/// `PathBuf` for use in one of our own `Dir` objects, and read a list of
/// its contents.
///
/// Returns an IO error upon failure, but this shouldn't be used to check
/// if a `File` is a directory or not! For that, just use `is_directory()`.
pub fn to_dir(&self, scan_for_git: bool) -> IOResult<Dir> {
Dir::read_dir(&*self.path, scan_for_git)
}
/// Whether this file is a regular file on the filesystem - that is, not a
/// directory, a link, or anything else treated specially.
pub fn is_file(&self) -> bool {
self.metadata.is_file()
}
/// Whether this file is both a regular file *and* executable for the
/// current user. Executable files have different semantics than
/// executable directories, and so should be highlighted differently.
pub fn is_executable_file(&self) -> bool {
let bit = modes::USER_EXECUTE;
self.is_file() && (self.metadata.permissions().mode() & bit) == bit
}
/// Whether this file is a symlink on the filesystem.
pub fn is_link(&self) -> bool {
self.metadata.file_type().is_symlink()
}
/// Whether this file is a named pipe on the filesystem.
pub fn is_pipe(&self) -> bool {
self.metadata.file_type().is_fifo()
}
/// Whether this file is a char device on the filesystem.
pub fn is_char_device(&self) -> bool {
self.metadata.file_type().is_char_device()
}
/// Whether this file is a block device on the filesystem.
pub fn is_block_device(&self) -> bool {
self.metadata.file_type().is_block_device()
}
/// Whether this file is a socket on the filesystem.
pub fn is_socket(&self) -> bool {
self.metadata.file_type().is_socket()
}
/// Whether this file is a dotfile, based on its name. In Unix, file names
/// beginning with a dot represent system or configuration files, and
/// should be hidden by default.
pub fn is_dotfile(&self) -> bool {
self.name.starts_with('.')
}
/// Re-prefixes the path pointed to by this file, if it's a symlink, to
/// make it an absolute path that can be accessed from whichever
/// directory exa is being run from.
fn reorient_target_path(&self, path: &Path) -> PathBuf {
if path.is_absolute() {
path.to_path_buf()
}
else if let Some(dir) = self.dir {
dir.join(&*path)
}
else if let Some(parent) = self.path.parent() {
parent.join(&*path)
}
else {
self.path.join(&*path)
}
}
/// Again assuming this file is a symlink, follows that link and returns
/// the result of following it.
///
/// For a working symlink that the user is allowed to follow,
/// this will be the `File` object at the other end, which can then have
/// its name, colour, and other details read.
///
/// For a broken symlink, returns where the file *would* be, if it
/// existed. If this file cannot be read at all, returns the error that
/// we got when we tried to read it.
pub fn link_target(&self) -> FileTarget<'dir> {
// We need to be careful to treat the path actually pointed to by
// this file -- which could be absolute or relative -- to the path
// we actually look up and turn into a `File` -- which needs to be
// absolute to be accessible from any directory.
let display_path = match fs::read_link(&self.path) {
Ok(path) => path,
Err(e) => return FileTarget::Err(e),
};
let target_path = self.reorient_target_path(&*display_path);
// Use plain `metadata` instead of `symlink_metadata` - we *want* to
// follow links.
if let Ok(metadata) = fs::metadata(&target_path) {
FileTarget::Ok(File::with_metadata(metadata, &*display_path, None))
}
else {
FileTarget::Broken(display_path)
}
}
/// This file's number of hard links.
///
/// It also reports whether this is both a regular file, and a file with
/// multiple links. This is important, because a file with multiple links
/// is uncommon, while you can come across directories and other types
/// with multiple links much more often. Thus, it should get highlighted
/// more attentively.
pub fn links(&self) -> f::Links {
let count = self.metadata.nlink();
f::Links {
count: count,
multiple: self.is_file() && count > 1,
}
}
/// This file's inode.
pub fn inode(&self) -> f::Inode {
f::Inode(self.metadata.ino())
}
/// This file's number of filesystem blocks.
///
/// (Not the size of each block, which we don't actually report on)
pub fn blocks(&self) -> f::Blocks {
if self.is_file() || self.is_link() {
f::Blocks::Some(self.metadata.blocks())
}
else {
f::Blocks::None
}
}
/// The ID of the user that own this file.
pub fn user(&self) -> f::User {
f::User(self.metadata.uid())
}
/// The ID of the group that owns this file.
pub fn group(&self) -> f::Group {
f::Group(self.metadata.gid())
}
/// This files size, if its a regular file.
///
/// For directories, no size is given. Although they do have a size on
/// some filesystems, Ive never looked at one of those numbers and gained
/// any information from it. So its going to be hidden instead.
///
/// Block and character devices return their device IDs, because they
/// usually just have a file size of zero.
pub fn size(&self) -> f::Size {
if self.is_directory() {
f::Size::None
}
else if self.is_char_device() || self.is_block_device() {
let dev = self.metadata.rdev();
f::Size::DeviceIDs(f::DeviceIDs {
major: (dev / 256) as u8,
minor: (dev % 256) as u8,
})
}
else {
f::Size::Some(self.metadata.len())
}
}
pub fn modified_time(&self) -> f::Time {
f::Time(self.metadata.mtime())
}
pub fn created_time(&self) -> f::Time {
f::Time(self.metadata.ctime())
}
pub fn accessed_time(&self) -> f::Time {
f::Time(self.metadata.mtime())
}
/// This file's 'type'.
///
/// This is used in the leftmost column of the permissions column.
/// Although the file type can usually be guessed from the colour of the
/// file, `ls` puts this character there, so people will expect it.
pub fn type_char(&self) -> f::Type {
if self.is_file() {
f::Type::File
}
else if self.is_directory() {
f::Type::Directory
}
else if self.is_pipe() {
f::Type::Pipe
}
else if self.is_link() {
f::Type::Link
}
else if self.is_char_device() {
f::Type::CharDevice
}
else if self.is_block_device() {
f::Type::BlockDevice
}
else if self.is_socket() {
f::Type::Socket
}
else {
f::Type::Special
}
}
/// This files permissions, with flags for each bit.
pub fn permissions(&self) -> f::Permissions {
let bits = self.metadata.mode();
let has_bit = |bit| { bits & bit == bit };
f::Permissions {
user_read: has_bit(modes::USER_READ),
user_write: has_bit(modes::USER_WRITE),
user_execute: has_bit(modes::USER_EXECUTE),
group_read: has_bit(modes::GROUP_READ),
group_write: has_bit(modes::GROUP_WRITE),
group_execute: has_bit(modes::GROUP_EXECUTE),
other_read: has_bit(modes::OTHER_READ),
other_write: has_bit(modes::OTHER_WRITE),
other_execute: has_bit(modes::OTHER_EXECUTE),
sticky: has_bit(modes::STICKY),
setgid: has_bit(modes::SETGID),
setuid: has_bit(modes::SETUID),
}
}
/// Whether this file's extension is any of the strings that get passed in.
///
/// This will always return `false` if the file has no extension.
pub fn extension_is_one_of(&self, choices: &[&str]) -> bool {
match self.ext {
Some(ref ext) => choices.contains(&&ext[..]),
None => false,
}
}
/// Whether this file's name, including extension, is any of the strings
/// that get passed in.
pub fn name_is_one_of(&self, choices: &[&str]) -> bool {
choices.contains(&&self.name[..])
}
/// This file's Git status as two flags: one for staged changes, and the
/// other for unstaged changes.
///
/// This requires looking at the `git` field of this file's parent
/// directory, so will not work if this file has just been passed in on
/// the command line.
pub fn git_status(&self) -> f::Git {
use std::env::current_dir;
match self.dir {
None => f::Git { staged: f::GitStatus::NotModified, unstaged: f::GitStatus::NotModified },
Some(d) => {
let cwd = match current_dir() {
Err(_) => Path::new(".").join(&self.path),
Ok(dir) => dir.join(&self.path),
};
d.git_status(&cwd, self.is_directory())
},
}
}
}
impl<'a> AsRef<File<'a>> for File<'a> {
fn as_ref(&self) -> &File<'a> {
self
}
}
/// Extract an extension from a file path, if one is present, in lowercase.
///
/// The extension is the series of characters after the last dot. This
/// deliberately counts dotfiles, so the ".git" folder has the extension "git".
///
/// ASCII lowercasing is used because these extensions are only compared
/// against a pre-compiled list of extensions which are known to only exist
/// within ASCII, so it's alright.
fn ext(path: &Path) -> Option<String> {
use std::ascii::AsciiExt;
let name = match path.file_name() {
Some(f) => f.to_string_lossy().to_string(),
None => return None,
};
name.rfind('.').map(|p| name[p+1..].to_ascii_lowercase())
}
/// The result of following a symlink.
pub enum FileTarget<'dir> {
/// The symlink pointed at a file that exists.
Ok(File<'dir>),
/// The symlink pointed at a file that does not exist. Holds the path
/// where the file would be, if it existed.
Broken(PathBuf),
/// There was an IO error when following the link. This can happen if the
/// file isnt a link to begin with, but also if, say, we dont have
/// permission to follow it.
Err(IOError),
// Err is its own variant, instead of having the whole thing be inside an
// `IOResult`, because being unable to follow a symlink is not a serious
// error -- we just display the error message and move on.
}
impl<'dir> FileTarget<'dir> {
/// Whether this link doesnt lead to a file, for whatever reason. This
/// gets used to determine how to highlight the link in grid views.
pub fn is_broken(&self) -> bool {
match *self {
FileTarget::Ok(_) => false,
FileTarget::Broken(_) | FileTarget::Err(_) => true,
}
}
}
/// More readable aliases for the permission bits exposed by libc.
#[allow(trivial_numeric_casts)]
mod modes {
use libc;
pub type Mode = u32;
// The `libc::mode_t` types actual type varies, but the value returned
// from `metadata.permissions().mode()` is always `u32`.
pub const USER_READ: Mode = libc::S_IRUSR as Mode;
pub const USER_WRITE: Mode = libc::S_IWUSR as Mode;
pub const USER_EXECUTE: Mode = libc::S_IXUSR as Mode;
pub const GROUP_READ: Mode = libc::S_IRGRP as Mode;
pub const GROUP_WRITE: Mode = libc::S_IWGRP as Mode;
pub const GROUP_EXECUTE: Mode = libc::S_IXGRP as Mode;
pub const OTHER_READ: Mode = libc::S_IROTH as Mode;
pub const OTHER_WRITE: Mode = libc::S_IWOTH as Mode;
pub const OTHER_EXECUTE: Mode = libc::S_IXOTH as Mode;
pub const STICKY: Mode = libc::S_ISVTX as Mode;
pub const SETGID: Mode = libc::S_ISGID as Mode;
pub const SETUID: Mode = libc::S_ISUID as Mode;
}
#[cfg(test)]
mod test {
use super::ext;
use std::path::Path;
#[test]
fn extension() {
assert_eq!(Some("dat".to_string()), ext(Path::new("fester.dat")))
}
#[test]
fn dotfile() {
assert_eq!(Some("vimrc".to_string()), ext(Path::new(".vimrc")))
}
#[test]
fn no_extension() {
assert_eq!(None, ext(Path::new("jarlsberg")))
}
}