better xtask run as sudo command

.cargo/config.toml

@@ -1,5 +1,6 @@
 [alias]
 xtask = "run --package xtask --"
+surun = "run --package xtask -- surun"
 
 [target.x86_64-unknown-linux-gnu]
 rustflags = [

.github/workflows/integration.yaml

@@ -46,7 +46,7 @@ jobs:
       - name: Integration tests
         if: endsWith(matrix.platform.target, 'musl')
         run: |
-            cargo xtask test \
+            cargo xtask test-suite \
                 --force-architest \
                 --target=${{ matrix.platform.target }} \
                 --kernel-versions=${{ matrix.platform.kernel-versions }} \

xtask/Cargo.toml

@@ -11,9 +11,15 @@ clap = { workspace = true, features = ["derive"] }
 flate2 = { workspace = true }
 indicatif = { workspace = true }
 num_cpus = { workspace = true }
-reqwest = { workspace = true, default-features = false, features = ["blocking", "json", "rustls-tls"] }
+reqwest = { workspace = true, default-features = false, features = [
+    "blocking",
+    "json",
+    "rustls-tls",
+] }
 serde = { workspace = true, features = ["derive"] }
 signal-hook = { workspace = true }
 tar = { workspace = true }
 uuid = { workspace = true, features = ["v4"] }
 xshell = { workspace = true }
+log = { workspace = true }
+env_logger = { workspace = true }

xtask/README.md

@@ -11,26 +11,26 @@ with `sudo`.
 
 To run the eBPF test suite you can use:
 ```sh
-cargo xtask test
+cargo xtask test-suite
 ```
 
 ## Run pulsar daemon
 
 To run the agent daemon you can use:
 ```sh
-cargo xtask pulsard
+cargo surun pulsard
 ```
 
 ## Run pulsar client
 
 To run the agent client you can use:
 ```sh
-cargo xtask pulsar
+cargo surun pulsar
 ```
 
 ## Run single probe
 
 To run a single module you can use:
 ```sh
-cargo xtask probe file-system-monitor
+cargo surun --example standalone-probes file-system-monitor
 ```

xtask/src/lib.rs

@@ -0,0 +1 @@
+pub mod surun;

xtask/src/main.rs

@@ -1,10 +1,9 @@
 use clap::Parser;
-use run::run_with_sudo;
 use signal_hook::{consts::TERM_SIGNALS, iterator::Signals};
+use xtask::surun::SuRunCommand;
 
-mod run;
 mod tempdir;
-mod test;
+mod test_suite;
 mod vmlinux;
 
 #[derive(Debug, Parser)]
@@ -16,29 +15,26 @@ pub struct Options {
 
 #[derive(Debug, Parser)]
 enum Command {
-    /// Run pulsar daemon with admin privileges
-    Pulsard(run::Options),
-    /// Run pulsar cli with admin privileges
-    Pulsar(run::Options),
-    /// Run a single module with admin privileges
-    Probe(run::Options),
+    /// Same as `cargo run` but with admin privileges (using `sudo -E` as runner)
+    #[clap(name = "surun")]
+    SuRun(SuRunCommand),
     /// Run eBPF test suite with admin privileges
-    Test(test::Options),
+    TestSuite(test_suite::Options),
     /// Build headers with BTF type definitions.
     Vmlinux(vmlinux::Options),
 }
 
 fn main() {
     let opts = Options::parse();
 
+    env_logger::init();
+
     // Drop term signals: register a handler, but never check it
     let _ = Signals::new(TERM_SIGNALS).expect("error setting signal handler");
 
     let ret = match opts.command {
-        Command::Pulsard(opts) => run_with_sudo("pulsar-exec", &["pulsard"], opts),
-        Command::Pulsar(opts) => run_with_sudo("pulsar-exec", &["pulsar"], opts),
-        Command::Probe(opts) => run_with_sudo("probe", &[], opts),
-        Command::Test(opts) => test::run(opts),
+        Command::SuRun(cmd) => cmd.run(),
+        Command::TestSuite(opts) => test_suite::run(opts),
         Command::Vmlinux(opts) => vmlinux::run(opts),
     };
 

xtask/src/surun.rs

@@ -0,0 +1,91 @@
+use anyhow::{bail, Context, Result};
+use clap::Parser;
+use xshell::{cmd, Shell};
+
+#[derive(Debug, Parser)]
+pub struct SuRunCommand {
+    /// Arguments normally passed to `cargo run`
+    #[clap(name = "ARGS", allow_hyphen_values = true)]
+    pub run_args: Vec<String>,
+}
+
+impl SuRunCommand {
+    pub fn run(&self) -> Result<()> {
+        let cargo = std::env::var("CARGO").unwrap();
+
+        // To determine the target triple it checks in order:
+        // - `--target` command line option
+        // - `CARGO_BUILD_TARGET` environment variable
+        // - default host target
+        //
+        // TODO: it should check also hierarchical `config.toml` files as described
+        // in the following page:
+        // https://doc.rust-lang.org/cargo/reference/config.html#hierarchical-structure
+        let target_triple = match self
+            .run_args
+            .iter()
+            .skip_while(|arg| *arg != "--target")
+            .nth(1) // skip the `--target` identifier
+        {
+            Some(target_triple) => target_triple.to_owned(),
+            None => {
+                const TARGET_TRIPLE_ENV: &str = "CARGO_BUILD_TARGET";
+
+                match std::env::var(TARGET_TRIPLE_ENV) {
+                    Ok(target_triple) => target_triple,
+                    Err(std::env::VarError::NotPresent) => {
+                        get_default_target(&cargo)
+                            .context(format!("failed to get target triple with {cargo}"))?
+                    }
+                    Err(std::env::VarError::NotUnicode(var)) => {
+                        bail!("env variable `{TARGET_TRIPLE_ENV}` doesn't contain a valid unicode: {var:?}")
+                    }
+                }
+            }
+        };
+
+        log::debug!("Detected host triple: {target_triple}");
+
+        let target_triple_env_runner = {
+            let tt_env_format = target_triple.to_uppercase().replace("-", "_");
+            format!("CARGO_TARGET_{tt_env_format}_RUNNER")
+        };
+
+        log::debug!("Overriding env variable: {target_triple_env_runner}");
+
+        let sh = Shell::new()?;
+
+        sh.set_var(target_triple_env_runner, "sudo -E");
+
+        let args = &self.run_args;
+
+        cmd!(sh, "{cargo} run {args...}").run()?;
+
+        Ok(())
+    }
+}
+
+/// Calls `cargo -vV`` in a subprocess and returns the default Clang target triple.
+fn get_default_target(cargo_path: &str) -> Result<String> {
+    /// The [`rustc`][1] output field name that shows the target.
+    ///
+    /// [1]: https://doc.rust-lang.org/rustc/what-is-rustc.html
+    const TARGET_FIELD: &str = "host: ";
+
+    // Query rustc for defaults.
+    let output = std::process::Command::new(cargo_path)
+        .arg("-vV")
+        .output()
+        .context(format!("failed to execute `{cargo_path} -vV`"))?;
+
+    // Decode stdout.
+    let stdout = std::str::from_utf8(&output.stdout).context("failed to read stdout into uft8")?;
+
+    // Parse the default target from stdout.
+    stdout
+        .lines()
+        .find(|l| l.starts_with(TARGET_FIELD))
+        .map(|l| &l[TARGET_FIELD.len()..])
+        .context(format!("failed to parse target from {cargo_path} output"))
+        .map(str::to_owned)
+}