Implement third-party exercises trust handling

Cargo.lock

@@ -253,6 +253,27 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6184e33543162437515c2e2b48714794e37845ec9851711914eec9d308f6ebe8"
 
+[[package]]
+name = "dirs"
+version = "5.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44c45a9d03d6676652bcb5e724c7e988de1acad23a711b5217ab9cbecbec2225"
+dependencies = [
+ "dirs-sys",
+]
+
+[[package]]
+name = "dirs-sys"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "520f05a5cbd335fae5a99ff7a6ab8627577660ee5cfd6a94a6a929b52ff0321c"
+dependencies = [
+ "libc",
+ "option-ext",
+ "redox_users",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "doc-comment"
 version = "0.3.3"
@@ -320,6 +341,17 @@ dependencies = [
  "toml_edit",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94b22e06ecb0110981051723910cbf0b5f5e09a2062dd7663334ee79a9d1286c"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.14.3"
@@ -428,6 +460,16 @@ version = "0.2.153"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c198f91728a82281a64e1f4f9eeb25d82cb32a5de251c6bd1b5154d63a8e7bd"
 
+[[package]]
+name = "libredox"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0ff37bd590ca25063e35af745c343cb7a0271906fb7b37e4813e8f79f00268d"
+dependencies = [
+ "bitflags 2.5.0",
+ "libc",
+]
+
 [[package]]
 name = "linux-raw-sys"
 version = "0.4.13"
@@ -528,6 +570,12 @@ version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
 
+[[package]]
+name = "option-ext"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "04744f49eae99ab78e0d5c0b603ab218f515ea8cfe5a456d7629ad883a3b6e7d"
+
 [[package]]
 name = "parking_lot"
 version = "0.12.1"
@@ -634,6 +682,17 @@ dependencies = [
  "bitflags 1.3.2",
 ]
 
+[[package]]
+name = "redox_users"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bd283d9651eeda4b2a83a43c1c91b266c40fd76ecd39a50a8c630ae69dc72891"
+dependencies = [
+ "getrandom",
+ "libredox",
+ "thiserror",
+]
+
 [[package]]
 name = "regex"
 version = "1.10.4"
@@ -684,6 +743,7 @@ dependencies = [
  "assert_cmd",
  "clap",
  "crossterm",
+ "dirs",
  "hashbrown",
  "notify-debouncer-mini",
  "predicates",
@@ -865,6 +925,26 @@ version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3369f5ac52d5eb6ab48c6b4ffdc8efbcad6b89c765749064ba298f2c68a16a76"
 
+[[package]]
+name = "thiserror"
+version = "1.0.58"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "03468839009160513471e86a034bb2c5c0e4baae3b43f79ffc55c4a5427b3297"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.58"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c61f3ba182994efc43764a46c018c347bc492c79f024e705f46567b418f6d4f7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.58",
+]
+
 [[package]]
 name = "toml_datetime"
 version = "0.6.5"

Cargo.toml

@@ -37,6 +37,7 @@ edition.workspace = true
 anyhow.workspace = true
 clap = { version = "4.5.4", features = ["derive"] }
 crossterm = "0.27.0"
+dirs = "5.0.1"
 hashbrown = "0.14.3"
 notify-debouncer-mini = "0.4.1"
 ratatui = "0.26.1"

src/init.rs

@@ -6,7 +6,7 @@ use std::{
     path::Path,
 };
 
-use crate::{embedded::EMBEDDED_FILES, info_file::ExerciseInfo};
+use crate::{embedded::EMBEDDED_FILES, info_file::ExerciseInfo, trust::trust_current_dir};
 
 fn create_cargo_toml(exercise_infos: &[ExerciseInfo]) -> io::Result<()> {
     let mut cargo_toml = Vec::with_capacity(1 << 13);
@@ -85,6 +85,8 @@ pub fn init(exercise_infos: &[ExerciseInfo]) -> Result<()> {
 
     create_vscode_dir().context("Failed to create the file `rustlings/.vscode/extensions.json`")?;
 
+    trust_current_dir()?;
+
     Ok(())
 }
 

src/main.rs

@@ -1,5 +1,4 @@
 use anyhow::{Context, Result};
-use app_state::StateFileStatus;
 use clap::{Parser, Subcommand};
 use crossterm::{
     terminal::{Clear, ClearType},
@@ -19,14 +18,16 @@ mod init;
 mod list;
 mod progress_bar;
 mod run;
+mod trust;
 mod watch;
 
 use self::{
-    app_state::AppState,
+    app_state::{AppState, StateFileStatus},
     info_file::InfoFile,
     init::init,
     list::list,
     run::run,
+    trust::{current_dir_is_trusted, trust_current_dir},
     watch::{watch, WatchExit},
 };
 
@@ -61,6 +62,11 @@ enum Subcommands {
         /// The name of the exercise
         name: String,
     },
+    /// Trust the current directory with its exercises.
+    ///
+    /// You only need to run this if you want to work on third-party exercises or after you moved
+    /// the official exercises that were initialized with `rustlings init`.
+    Trust,
 }
 
 fn main() -> Result<()> {
@@ -72,14 +78,26 @@ fn main() -> Result<()> {
 
     if matches!(args.command, Some(Subcommands::Init)) {
         init(&info_file.exercises).context("Initialization failed")?;
-
         println!("{POST_INIT_MSG}");
         return Ok(());
-    } else if !Path::new("exercises").is_dir() {
+    }
+
+    if !Path::new("exercises").is_dir() {
         println!("{PRE_INIT_MSG}");
         exit(1);
     }
 
+    if matches!(args.command, Some(Subcommands::Trust)) {
+        trust_current_dir()?;
+        println!("{POST_TRUST_MSG}");
+        return Ok(());
+    }
+
+    if !current_dir_is_trusted()? {
+        println!("{NOT_TRUSTED_MSG}");
+        exit(1);
+    }
+
     let (mut app_state, state_file_status) = AppState::new(
         info_file.exercises,
         info_file.final_message.unwrap_or_default(),
@@ -130,8 +148,6 @@ fn main() -> Result<()> {
                 }
             }
         }
-        // `Init` is handled above.
-        Some(Subcommands::Init) => (),
         Some(Subcommands::Run { name }) => {
             if let Some(name) = name {
                 app_state.set_current_exercise_by_name(&name)?;
@@ -149,6 +165,8 @@ fn main() -> Result<()> {
             app_state.set_current_exercise_by_name(&name)?;
             println!("{}", app_state.current_exercise().hint);
         }
+        // `Init` and `Trust` are handled above.
+        Some(Subcommands::Init | Subcommands::Trust) => (),
     }
 
     Ok(())
@@ -158,8 +176,13 @@ const CARGO_NOT_FOUND_ERR: &str = "Failed to find `cargo`.
 Did you already install Rust?
 Try running `cargo --version` to diagnose the problem.";
 
+const POST_INIT_MSG: &str = "Done initialization!
+
+Run `cd rustlings` to go into the generated directory.
+Then run `rustlings` to get started.";
+
 const PRE_INIT_MSG: &str = r"
-       welcome to...
+       Welcome to...
                  _   _ _
   _ __ _   _ ___| |_| (_)_ __   __ _ ___
  | '__| | | / __| __| | | '_ \ / _` / __|
@@ -170,11 +193,19 @@ const PRE_INIT_MSG: &str = r"
 The `exercises` directory wasn't found in the current directory.
 If you are just starting with Rustlings, run the command `rustlings init` to initialize it.";
 
-const POST_INIT_MSG: &str = "
+const POST_TRUST_MSG: &str = "You now trust the exercises in the current directory.
-Done initialization!
+Run `rustlings` to start working on them.";
 
-Run `cd rustlings` to go into the generated directory.
+const NOT_TRUSTED_MSG: &str = "It looks like you are trying to work on third-party exercises.
-Then run `rustlings` to get started.";
+Rustlings supports third-party exercises. But because Rustlings runs the code inside an exercise,
+we need to warn you about the possibility of malicious code.
+We recommend that you read all the exercise files in the `exercises` directory and check the
+dependencies in the `Cargo.toml` file.
+If everything looks fine and you want to trust this directory, run `rustlings trust`.
+
+If you you are trying to work on the official exercises that were generated using `rustlings init`,
+then you probably moved the directory containing them. In that case, you can run `rustlings trust`
+without a problem.";
 
 const FENISH_LINE: &str = "+----------------------------------------------------+
 |          You made it to the Fe-nish line!          |

src/trust.rs

@@ -0,0 +1,72 @@
+use anyhow::{Context, Error, Result};
+use std::{
+    env,
+    fs::{self, OpenOptions},
+    io::{ErrorKind, Write},
+};
+
+const DATA_DIR_NAME: &str = "rustlings";
+const TRUSTED_DIRS_FILE_NAME: &str = "trusted-dirs.txt";
+
+pub fn trust_current_dir() -> Result<()> {
+    let mut path = dirs::data_dir().context("Failed to determine the data directory")?;
+    path.push(DATA_DIR_NAME);
+    if !path.is_dir() {
+        fs::create_dir(&path)
+            .with_context(|| format!("Failed to create the directory {}", path.display()))?;
+    }
+
+    path.push(TRUSTED_DIRS_FILE_NAME);
+    let mut file = OpenOptions::new()
+        .create(true)
+        .append(true)
+        .open(&path)
+        .with_context(|| {
+            format!(
+                "Failed to create/open the file {} in write mode",
+                path.display(),
+            )
+        })?;
+
+    let dir = env::current_dir().context("Failed to get the current directory path")?;
+    let dir = dir.to_string_lossy();
+    let mut line = Vec::with_capacity(dir.as_bytes().len() + 1);
+    line.extend_from_slice(dir.as_bytes());
+    line.push(b'\n');
+
+    file.write_all(&line)
+        .with_context(|| format!("Failed to append to the file {}", path.display()))
+}
+
+pub fn current_dir_is_trusted() -> Result<bool> {
+    let mut path = dirs::data_dir().context("Failed to determine the data directory")?;
+    path.push(DATA_DIR_NAME);
+    path.push(TRUSTED_DIRS_FILE_NAME);
+
+    let content = match fs::read(&path) {
+        Ok(v) => v,
+        Err(e) => match e.kind() {
+            ErrorKind::NotFound => return Ok(false),
+            _ => {
+                return Err(
+                    Error::from(e).context(format!("Failed to read the file {}", path.display()))
+                )
+            }
+        },
+    };
+
+    let current_dir = env::current_dir().context("Failed to get the current directory path")?;
+    let current_dir = current_dir.to_string_lossy();
+
+    for line in content.split(|c| *c == b'\n') {
+        if line.is_empty() {
+            break;
+        }
+
+        if line == current_dir.as_bytes() {
+            return Ok(true);
+        }
+    }
+
+    Ok(false)
+}