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Applications: Properly parse desktop exec keys and stop shelling out #207

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Applications: Properly parse desktop exec keys and stop shelling out #207

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45 changes: 20 additions & 25 deletions plugins/applications/src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
use abi_stable::std_types::{ROption, RString, RVec};
use anyrun_plugin::{anyrun_interface::HandleResult, *};
use fuzzy_matcher::FuzzyMatcher;
use scrubber::DesktopEntry;
use scrubber::{DesktopEntry, lower_exec};
use serde::Deserialize;
use std::{env, fs, process::Command};

Expand Down Expand Up @@ -48,17 +48,17 @@ pub fn handler(selection: Match, state: &State) -> HandleResult {
}
})
.unwrap();
let (command, argv) = lower_exec(&entry.exec).unwrap_or_else(
|e| panic!("Unable to parse the exec key `{}`: {}", &entry.exec, e.0)
);

if entry.term {
match &state.config.terminal {
Some(term) => {
if let Err(why) = Command::new("sh")
.arg("-c")
.arg(format!(
"{} {}",
term.command,
term.args.replace("{}", &entry.exec)
))
if let Err(why) = Command::new(&term.command)
.arg(&term.args)
.arg(command)
.args(argv)
.spawn()
{
eprintln!("Error running desktop entry: {}", why);
Expand All @@ -68,23 +68,23 @@ pub fn handler(selection: Match, state: &State) -> HandleResult {
let sensible_terminals = &[
Terminal {
command: "alacritty".to_string(),
args: "-e {}".to_string(),
args: "-e".to_string(),
},
Terminal {
command: "foot".to_string(),
args: "-e \"{}\"".to_string(),
args: "-e".to_string(),
},
Terminal {
command: "kitty".to_string(),
args: "-e \"{}\"".to_string(),
args: "-e".to_string(),
},
Terminal {
command: "wezterm".to_string(),
args: "-e \"{}\"".to_string(),
args: "-e".to_string(),
},
Terminal {
command: "wterm".to_string(),
args: "-e \"{}\"".to_string(),
args: "-e".to_string(),
},
];
for term in sensible_terminals {
Expand All @@ -93,13 +93,10 @@ pub fn handler(selection: Match, state: &State) -> HandleResult {
.output()
.is_ok_and(|output| output.status.success())
{
if let Err(why) = Command::new("sh")
.arg("-c")
.arg(format!(
"{} {}",
term.command,
term.args.replace("{}", &entry.exec)
))
if let Err(why) = Command::new(&term.command)
.arg(&term.args)
.arg(command)
.args(argv)
.spawn()
{
eprintln!("Error running desktop entry: {}", why);
Expand All @@ -112,9 +109,8 @@ pub fn handler(selection: Match, state: &State) -> HandleResult {
} else if let Err(why) = {
let current_dir = &env::current_dir().unwrap();

Command::new("sh")
.arg("-c")
.arg(&entry.exec)
Command::new(command)
.args(argv)
.current_dir(if let Some(path) = &entry.path {
if path.exists() {
path
Expand All @@ -123,8 +119,7 @@ pub fn handler(selection: Match, state: &State) -> HandleResult {
}
} else {
current_dir
})
.spawn()
}).spawn()
} {
eprintln!("Error running desktop entry: {}", why);
}
Expand Down
203 changes: 195 additions & 8 deletions plugins/applications/src/scrubber.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,200 @@ const FIELD_CODE_LIST: &[&str] = &[
"%f", "%F", "%u", "%U", "%d", "%D", "%n", "%N", "%i", "%c", "%k", "%v", "%m",
];

// See https://specifications.freedesktop.org/desktop-entry-spec/latest/exec-variables.html
const EXEC_ESCAPE_CHARS: &[char] = &['"', '`', '$', '\\'];

/*
Reserved characters are space (" "), tab, newline, double quote,
single quote ("'"), backslash character ("\"), greater-than sign
(">"), less-than sign ("<"), tilde ("~"), vertical bar ("|"),
ampersand ("&"), semicolon (";"), dollar sign ("$"), asterisk ("*"),
question mark ("?"), hash mark ("#"), parenthesis ("(") and (")") and
backtick character ("`").
*/
const EXEC_RESERVED_CHARS: &[char] = &[
' ', '\t', '\n', '"', '\'', '\\', '>', '<', '~', '|', '&', ';', '$', '*', '?', '#', '(', ')',
'`',
];

// \s, \n, \t, \r, and \\ are valid escapes in Desktop strings
const DESKTOP_STRING_ESCAPES: &[(char, char)] = &[
('s', ' '),
('n', '\n'),
('t', '\t'),
('r', '\r'),
('\\', '\\'),
];

fn get_desktop_string_escapes() -> HashMap<char, char> {
HashMap::from_iter(DESKTOP_STRING_ESCAPES.iter().cloned())
}

#[derive(Debug, Clone)]
pub struct ExecKeyError(pub String);

#[derive(Debug, Clone)]
enum StringEscapeState {
Waiting,
Escape,
}

fn substitute_escapes(s: &str) -> Result<String, ExecKeyError> {
use StringEscapeState::*;

let escapes = get_desktop_string_escapes();
let mut state = Waiting;
let mut out = Vec::<char>::new();
for (i, c) in s.chars().enumerate() {
match state {
Waiting => match c {
'\\' => {
state = Escape;
}
_ => {
out.push(c);
}
},
Escape => match c {
c if escapes.contains_key(&c) => {
out.push(*escapes.get(&c).unwrap());
state = Waiting;
}
_ => {
return Err(ExecKeyError(format!(
"Escaping invalid character {} at position {}",
c, i
)))
}
},
}
}
if let Escape = state {
return Err(ExecKeyError("Dangling escape".to_string()));
}
Ok(out.into_iter().collect())
}

#[derive(Debug, Clone)]
enum ExecKeyState {
Waiting,
Word,
Quoting,
Escape,
}

fn unescape_exec(s: &str) -> Result<Vec<String>, ExecKeyError> {
use ExecKeyState::*;

let mut state = Waiting;
let mut out = Vec::<String>::new();
let mut buffer = Vec::<char>::new();

for (i, c) in s.chars().enumerate() {
match state {
Waiting => {
match c {
'"' => {
state = Quoting;
continue;
}
' ' => continue,
c if EXEC_RESERVED_CHARS.contains(&c) => return Err(ExecKeyError(format!(
"Starting word with reserved character {} at position {}, consider quoting",
c, i
))),
_ => {
state = Word;
}
};
buffer.push(c);
}
Word => match c {
' ' => {
state = Waiting;
out.push(buffer.iter().collect());
buffer.clear();
}
c if EXEC_RESERVED_CHARS.contains(&c) => {
return Err(ExecKeyError(format!(
"Reserved character {} in unquoted word at position {}",
c, i
)))
}
_ => buffer.push(c),
},
Quoting => match c {
'"' => {
out.push(buffer.iter().collect());
buffer.clear();
state = Waiting;
continue;
}
'\\' => state = Escape,
c if EXEC_ESCAPE_CHARS.contains(&c) => {
return Err(ExecKeyError(format!(
"Unescaped character {} in quoted string at position {}",
c, i
)));
}
_ => {
buffer.push(c);
}
},
Escape => match c {
c if EXEC_ESCAPE_CHARS.contains(&c) => {
buffer.push(c);
state = Quoting;
}
_ => {
return Err(ExecKeyError(format!(
"Escaping invalid character {} in quoted string at position {}",
c, i
)))
}
},
}
}
match state {
Waiting => {}
Word => {
out.push(buffer.iter().collect());
buffer.clear();
}
_ => return Err(ExecKeyError("Invalid state at end of exec key".to_string())),
}

Ok(out)
}

/*
1. Substitute general desktop string escapes
2. Unescape EXEC_ESCAPE_CHARS in exec key quoted strings
3. Strip field codes and throw away empty args
*/
pub(crate) fn lower_exec(s: &str) -> Result<(String, Vec<String>), ExecKeyError> {
let subst = substitute_escapes(s)?;
let argvec = unescape_exec(&subst)?;
if let Some((command, argv)) = argvec.split_first() {
let argv_without_fieldcodes = argv
.to_vec()
.into_iter()
.map(|mut c| {
for field_code in FIELD_CODE_LIST.iter() {
c = c.replace(field_code, "");
}
c
})
.filter(|c| {
!c.is_empty()
})
.collect();
return Ok((command.clone(), argv_without_fieldcodes));
} else {
return Err(ExecKeyError("Empty exec key!".to_string()));
}
}

impl DesktopEntry {
fn from_dir_entry(entry: &fs::DirEntry, config: &Config) -> Vec<Self> {
if entry.path().extension() == Some(OsStr::new("desktop")) {
Expand Down Expand Up @@ -68,14 +262,7 @@ impl DesktopEntry {
}
{
Some(DesktopEntry {
exec: {
let mut exec = map.get("Exec")?.to_string();

for field_code in FIELD_CODE_LIST {
exec = exec.replace(field_code, "");
}
exec
},
exec: map.get("Exec")?.to_string(),
path: map.get("Path").map(PathBuf::from),
name: map.get("Name")?.to_string(),
keywords: map
Expand Down