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shred: implemented "--remove" arg (#5790)
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@Statheres
Statheres authored Jan 6, 2024
1 parent 247f2e5 commit c867d6b
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Showing 2 changed files with 158 additions and 24 deletions.
105 changes: 81 additions & 24 deletions src/uu/shred/src/shred.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,10 +28,17 @@ pub mod options {
pub const FILE: &str = "file";
pub const ITERATIONS: &str = "iterations";
pub const SIZE: &str = "size";
pub const WIPESYNC: &str = "u";
pub const REMOVE: &str = "remove";
pub const VERBOSE: &str = "verbose";
pub const EXACT: &str = "exact";
pub const ZERO: &str = "zero";

pub mod remove {
pub const UNLINK: &str = "unlink";
pub const WIPE: &str = "wipe";
pub const WIPESYNC: &str = "wipesync";
}
}

// This block size seems to match GNU (2^16 = 65536)
Expand Down Expand Up @@ -81,6 +88,14 @@ enum PassType {
Random,
}

#[derive(PartialEq, Clone, Copy)]
enum RemoveMethod {
None, // Default method. Only obfuscate the file data
Unlink, // The same as 'None' + unlink the file
Wipe, // The same as 'Unlink' + obfuscate the file name before unlink
WipeSync, // The same as 'Wipe' sync the file name changes
}

/// Iterates over all possible filenames of a certain length using NAME_CHARSET as an alphabet
struct FilenameIter {
// Store the indices of the letters of our filename in NAME_CHARSET
Expand Down Expand Up @@ -219,17 +234,25 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
None => unreachable!(),
};

// TODO: implement --remove HOW
// The optional HOW parameter indicates how to remove a directory entry:
// - 'unlink' => use a standard unlink call.
// - 'wipe' => also first obfuscate bytes in the name.
// - 'wipesync' => also sync each obfuscated byte to disk.
// The default mode is 'wipesync', but note it can be expensive.

// TODO: implement --random-source

let remove_method = if matches.get_flag(options::WIPESYNC) {
RemoveMethod::WipeSync
} else if matches.contains_id(options::REMOVE) {
match matches
.get_one::<String>(options::REMOVE)
.map(AsRef::as_ref)
{
Some(options::remove::UNLINK) => RemoveMethod::Unlink,
Some(options::remove::WIPE) => RemoveMethod::Wipe,
Some(options::remove::WIPESYNC) => RemoveMethod::WipeSync,
_ => unreachable!("should be caught by clap"),
}
} else {
RemoveMethod::None
};

let force = matches.get_flag(options::FORCE);
let remove = matches.get_flag(options::REMOVE);
let size_arg = matches
.get_one::<String>(options::SIZE)
.map(|s| s.to_string());
Expand All @@ -240,7 +263,14 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {

for path_str in matches.get_many::<String>(options::FILE).unwrap() {
show_if_err!(wipe_file(
path_str, iterations, remove, size, exact, zero, verbose, force,
path_str,
iterations,
remove_method,
size,
exact,
zero,
verbose,
force,
));
}
Ok(())
Expand Down Expand Up @@ -276,12 +306,26 @@ pub fn uu_app() -> Command {
.help("shred this many bytes (suffixes like K, M, G accepted)"),
)
.arg(
Arg::new(options::REMOVE)
Arg::new(options::WIPESYNC)
.short('u')
.long(options::REMOVE)
.help("truncate and remove file after overwriting; See below")
.help("deallocate and remove file after overwriting")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new(options::REMOVE)
.long(options::REMOVE)
.value_name("HOW")
.value_parser([
options::remove::UNLINK,
options::remove::WIPE,
options::remove::WIPESYNC,
])
.num_args(0..=1)
.require_equals(true)
.default_missing_value(options::remove::WIPESYNC)
.help("like -u but give control on HOW to delete; See below")
.action(ArgAction::Set),
)
.arg(
Arg::new(options::VERBOSE)
.long(options::VERBOSE)
Expand Down Expand Up @@ -340,7 +384,7 @@ fn pass_name(pass_type: &PassType) -> String {
fn wipe_file(
path_str: &str,
n_passes: usize,
remove: bool,
remove_method: RemoveMethod,
size: Option<u64>,
exact: bool,
zero: bool,
Expand Down Expand Up @@ -457,8 +501,8 @@ fn wipe_file(
.map_err_context(|| format!("{}: File write pass failed", path.maybe_quote())));
}

if remove {
do_remove(path, path_str, verbose)
if remove_method != RemoveMethod::None {
do_remove(path, path_str, verbose, remove_method)
.map_err_context(|| format!("{}: failed to remove file", path.maybe_quote()))?;
}
Ok(())
Expand Down Expand Up @@ -501,7 +545,7 @@ fn get_file_size(path: &Path) -> Result<u64, io::Error> {

// Repeatedly renames the file with strings of decreasing length (most likely all 0s)
// Return the path of the file after its last renaming or None if error
fn wipe_name(orig_path: &Path, verbose: bool) -> Option<PathBuf> {
fn wipe_name(orig_path: &Path, verbose: bool, remove_method: RemoveMethod) -> Option<PathBuf> {
let file_name_len = orig_path.file_name().unwrap().to_str().unwrap().len();

let mut last_path = PathBuf::from(orig_path);
Expand All @@ -526,12 +570,14 @@ fn wipe_name(orig_path: &Path, verbose: bool) -> Option<PathBuf> {
);
}

// Sync every file rename
let new_file = OpenOptions::new()
.write(true)
.open(new_path.clone())
.expect("Failed to open renamed file for syncing");
new_file.sync_all().expect("Failed to sync renamed file");
if remove_method == RemoveMethod::WipeSync {
// Sync every file rename
let new_file = OpenOptions::new()
.write(true)
.open(new_path.clone())
.expect("Failed to open renamed file for syncing");
new_file.sync_all().expect("Failed to sync renamed file");
}

last_path = new_path;
break;
Expand All @@ -552,12 +598,23 @@ fn wipe_name(orig_path: &Path, verbose: bool) -> Option<PathBuf> {
Some(last_path)
}

fn do_remove(path: &Path, orig_filename: &str, verbose: bool) -> Result<(), io::Error> {
fn do_remove(
path: &Path,
orig_filename: &str,
verbose: bool,
remove_method: RemoveMethod,
) -> Result<(), io::Error> {
if verbose {
show_error!("{}: removing", orig_filename.maybe_quote());
}

if let Some(rp) = wipe_name(path, verbose) {
let remove_path = if remove_method == RemoveMethod::Unlink {
Some(path.with_file_name(orig_filename))
} else {
wipe_name(path, verbose, remove_method)
};

if let Some(rp) = remove_path {
fs::remove_file(rp)?;
}

Expand Down
77 changes: 77 additions & 0 deletions tests/by-util/test_shred.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,15 +2,92 @@
//
// For the full copyright and license information, please view the LICENSE
// file that was distributed with this source code.

// spell-checker:ignore wipesync

use crate::common::util::TestScenario;

#[test]
fn test_invalid_arg() {
new_ucmd!().arg("--definitely-invalid").fails().code_is(1);
}

#[test]
fn test_invalid_remove_arg() {
new_ucmd!().arg("--remove=unknown").fails().code_is(1);
}

#[test]
fn test_shred() {
let (at, mut ucmd) = at_and_ucmd!();

let file = "test_shred";
let file_original_content = "test_shred file content";

at.write(file, file_original_content);

ucmd.arg(file).succeeds();

// File exists
assert!(at.file_exists(file));
// File is obfuscated
assert!(at.read_bytes(file) != file_original_content.as_bytes());
}

#[test]
fn test_shred_remove() {
let (at, mut ucmd) = at_and_ucmd!();

let file = "test_shred_remove";
at.touch(file);

ucmd.arg("--remove").arg(file).succeeds();

// File was deleted
assert!(!at.file_exists(file));
}

#[test]
fn test_shred_remove_unlink() {
let (at, mut ucmd) = at_and_ucmd!();

let file = "test_shred_remove_unlink";
at.touch(file);

ucmd.arg("--remove=unlink").arg(file).succeeds();

// File was deleted
assert!(!at.file_exists(file));
}

#[test]
fn test_shred_remove_wipe() {
let (at, mut ucmd) = at_and_ucmd!();

let file = "test_shred_remove_wipe";
at.touch(file);

ucmd.arg("--remove=wipe").arg(file).succeeds();

// File was deleted
assert!(!at.file_exists(file));
}

#[test]
fn test_shred_remove_wipesync() {
let (at, mut ucmd) = at_and_ucmd!();

let file = "test_shred_remove_wipesync";
at.touch(file);

ucmd.arg("--remove=wipesync").arg(file).succeeds();

// File was deleted
assert!(!at.file_exists(file));
}

#[test]
fn test_shred_u() {
let scene = TestScenario::new(util_name!());
let at = &scene.fixtures;

Expand Down

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