Add initial OpenVpnBuilder and tests

4 files changed, 95 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 949a029d45..fec2e1da5e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,6 +2,9 @@
 
 //! The core components of the talpidaemon VPN client.
 
+/// Working with processes.
+pub mod process;
+
 #[cfg(test)]
 mod tests {
     #[test]
diff --git a/src/process.rs b/src/process.rs
new file mode 100644
index 0000000000..066b0e7477
--- /dev/null
+++ b/src/process.rs
@@ -0,0 +1,50 @@
+use std::ffi::{OsString, OsStr};
+use std::io;
+use std::path::{Path, PathBuf};
+use std::process::{Command, Child, Stdio};
+
+/// An OpenVPN process builder, providing control over the different arguments that the OpenVPN
+/// binary accepts.
+pub struct OpenVpnBuilder {
+    openvpn_bin: OsString,
+    config: Option<PathBuf>,
+}
+
+impl OpenVpnBuilder {
+    /// Constructs a new `OpenVpnBuilder` for launching OpenVPN processes from the binary at
+    /// `openvpn_bin`.
+    pub fn new<P: AsRef<OsStr>>(openvpn_bin: P) -> Self {
+        OpenVpnBuilder {
+            openvpn_bin: OsString::from(openvpn_bin.as_ref()),
+            config: None,
+        }
+    }
+
+    /// Sets what configuration file will be given to OpenVPN
+    pub fn config<P: AsRef<Path>>(&mut self, path: P) -> &mut Self {
+        self.config = Some(path.as_ref().to_path_buf());
+        self
+    }
+
+    /// Executes the OpenVPN process as a child process, returning a handle to it.
+    pub fn spawn(&mut self) -> io::Result<Child> {
+        let mut command = self.create_command();
+        self.apply_settings(&mut command);
+        command.spawn()
+    }
+
+    fn create_command(&mut self) -> Command {
+        let mut command = Command::new(&self.openvpn_bin);
+        command.env_clear()
+            .stdin(Stdio::null())
+            .stdout(Stdio::null())
+            .stderr(Stdio::null());
+        command
+    }
+
+    fn apply_settings(&self, command: &mut Command) {
+        if let Some(config) = self.config.as_ref() {
+            command.arg("--config").arg(config);
+        }
+    }
+}
diff --git a/tests/process.rs b/tests/process.rs
new file mode 100644
index 0000000000..2cc5e51147
--- /dev/null
+++ b/tests/process.rs
@@ -0,0 +1,26 @@
+extern crate talpid_core;
+
+mod util;
+
+use talpid_core::process::OpenVpnBuilder;
+
+#[cfg(target_os = "linux")]
+#[test]
+fn openvpn_builder_starts_correct_process() {
+    let mut child = OpenVpnBuilder::new("echo").spawn().unwrap();
+    let args = util::read_args_for_proc(child.id());
+
+    assert_eq!(vec!["echo"], args);
+    child.kill().unwrap();
+}
+
+#[cfg(target_os = "linux")]
+#[test]
+fn openvpn_builder_passes_config() {
+    let config_path = "/path/to/config".to_owned();
+    let mut child = OpenVpnBuilder::new("echo").config(&config_path).spawn().unwrap();
+    let args = util::read_args_for_proc(child.id());
+
+    assert!(args.contains(&config_path));
+    child.kill().unwrap();
+}
diff --git a/tests/util.rs b/tests/util.rs
new file mode 100644
index 0000000000..8fe87e5783
--- /dev/null
+++ b/tests/util.rs
@@ -0,0 +1,16 @@
+use std::fs::File;
+use std::io::Read;
+use std::path::Path;
+
+pub fn read_file<P: AsRef<Path>>(path: P) -> String {
+    let mut string = String::new();
+    let mut f = File::open(path).unwrap();
+    f.read_to_string(&mut string).unwrap();
+    string
+}
+
+#[cfg(target_os = "linux")]
+pub fn read_args_for_proc(pid: u32) -> Vec<String> {
+    let cmdline = read_file(format!("/proc/{}/cmdline", pid));
+    cmdline.split_terminator('\0').map(String::from).collect()
+}