From cc4416562a82aa3aa80d806bc762965d60b3f5d1 Mon Sep 17 00:00:00 2001
From: Jordan Doyle <jordan@doyle.la>
Date: Wed, 28 Jun 2023 23:39:37 +0100
Subject: [PATCH] Start fleshing out filesystem and pwd tracking

---
 pisshoff-server/src/command.rs     | 44 ++++++++++++++++++++++++++++++++++++--------
 pisshoff-server/src/file_system.rs | 41 +++++++++++++++++++++++++++++++++++++++++
 pisshoff-server/src/main.rs        |  1 +
 pisshoff-server/src/server.rs      | 11 +++++++++++
 4 files changed, 89 insertions(+), 8 deletions(-)
 create mode 100644 pisshoff-server/src/file_system.rs

diff --git a/pisshoff-server/src/command.rs b/pisshoff-server/src/command.rs
index 1f82200..5e3c615 100644
--- a/pisshoff-server/src/command.rs
+++ b/pisshoff-server/src/command.rs
@@ -2,6 +2,7 @@ pub mod uname;
 
 use crate::server::Connection;
 use itertools::{Either, Itertools};
+use std::fmt::Write;
 use std::{f32, str::FromStr, time::Duration};
 use thrussh::{server::Session, ChannelId};
 
@@ -26,18 +27,45 @@ pub async fn run_command(
             session.data(channel, format!("{}\n", conn.username()).into());
         }
         "pwd" => {
-            // TODO: mock FHS
-            let username = conn.username();
-            let pwd = if conn.username() == "root" {
-                "/root\n".to_string()
+            session.data(
+                channel,
+                format!("{}\n", conn.file_system().pwd().display()).into(),
+            );
+        }
+        "ls" => {
+            let resp = if args.len() == 1 {
+                conn.file_system().ls(None).join("  ")
+            } else if args.len() == 2 {
+                conn.file_system().ls(Some(args.get(1).unwrap())).join("  ")
             } else {
-                format!("/home/{username}\n")
+                let mut out = String::new();
+
+                for dir in args.iter().skip(1) {
+                    if !out.is_empty() {
+                        out.push_str("\n\n");
+                    }
+
+                    write!(out, "{dir}:").unwrap();
+                    out.push_str(&conn.file_system().ls(Some(dir)).join("  "));
+                }
+
+                out
             };
 
-            session.data(channel, pwd.into());
+            if !resp.is_empty() {
+                session.data(channel, format!("{resp}\n").into());
+            }
         }
-        "ls" => {
-            // pretend /root is empty until we mock the FHS
+        "cd" => {
+            if args.len() > 2 {
+                session.data(
+                    channel,
+                    "-bash: cd: too many arguments\n".to_string().into(),
+                );
+                return;
+            }
+
+            conn.file_system().cd(args.get(1).map(String::as_str));
         }
         "exit" => {
             let exit_status = args
diff --git a/pisshoff-server/src/file_system.rs b/pisshoff-server/src/file_system.rs
new file mode 100644
index 0000000..5f96385
--- /dev/null
+++ b/pisshoff-server/src/file_system.rs
@@ -0,0 +1,41 @@
+#![allow(dead_code)]
+
+use std::path::{Path, PathBuf};
+
+/// A fake file system, stored in memory only active for the current session.
+pub struct FileSystem {
+    pwd: PathBuf,
+    home: PathBuf,
+}
+
+impl FileSystem {
+    pub fn new(user: &str) -> Self {
+        let pwd = if user == "root" {
+            PathBuf::new().join("/root")
+        } else {
+            PathBuf::new().join("/home").join(user)
+        };
+
+        Self {
+            home: pwd.clone(),
+            pwd,
+        }
+    }
+
+    pub fn cd(&mut self, v: Option<&str>) {
+        if let Some(v) = v {
+            self.pwd.push(v);
+        } else {
+            self.pwd = self.home.clone();
+        }
+    }
+
+    pub fn pwd(&self) -> &Path {
+        &self.pwd
+    }
+
+    #[allow(clippy::unused_self)]
+    pub fn ls(&self, _dir: Option<&str>) -> &[&str] {
+        &[]
+    }
+}
diff --git a/pisshoff-server/src/main.rs b/pisshoff-server/src/main.rs
index 379a4c4..71af86d 100644
--- a/pisshoff-server/src/main.rs
+++ b/pisshoff-server/src/main.rs
@@ -17,6 +17,7 @@ use tracing_subscriber::EnvFilter;
 mod audit;
 mod command;
 mod config;
+mod file_system;
 mod server;
 mod state;
 
diff --git a/pisshoff-server/src/server.rs b/pisshoff-server/src/server.rs
index ef29239..74389d8 100644
--- a/pisshoff-server/src/server.rs
+++ b/pisshoff-server/src/server.rs
@@ -2,6 +2,7 @@ use crate::audit::{
     ExecCommandEvent, SignalEvent, SubsystemRequestEvent, TcpIpForwardEvent, WindowAdjustedEvent,
     WindowChangeRequestEvent,
 };
+use crate::file_system::FileSystem;
 use crate::{
     audit::{
         AuditLog, AuditLogAction, LoginAttemptEvent, OpenDirectTcpIpEvent, OpenX11Event,
@@ -74,6 +75,7 @@ impl thrussh::server::Server for Server {
                 ..AuditLog::default()
             },
             username: None,
+            file_system: None,
         }
     }
 }
@@ -83,6 +85,7 @@ pub struct Connection {
     server: Server,
     audit_log: AuditLog,
     username: Option<String>,
+    file_system: Option<FileSystem>,
 }
 
 impl Connection {
@@ -90,6 +93,14 @@ impl Connection {
         self.username.as_deref().unwrap_or("root")
     }
 
+    pub fn file_system(&mut self) -> &mut FileSystem {
+        if self.file_system.is_none() {
+            self.file_system = Some(FileSystem::new(self.username()));
+        }
+
+        self.file_system.as_mut().unwrap()
+    }
+
     fn try_login(&mut self, user: &str, password: &str) -> bool {
         self.username = Some(user.to_string());
 
--
libgit2 1.7.2