fix: valgrind crash for unresolved libpython

Author: not-matthias

src/run/runner/valgrind/executor.rs

@@ -7,7 +7,7 @@ use crate::run::runner::{ExecutorName, RunData};
 use crate::run::{check_system::SystemInfo, config::Config};
 
 use super::setup::install_valgrind;
-use super::{helpers::perf_maps::harvest_perf_maps, measure};
+use super::{helpers::perf_maps::harvest_perf_maps, helpers::venv_compat, measure};
 
 pub struct ValgrindExecutor;
 
@@ -19,6 +19,13 @@ impl Executor for ValgrindExecutor {
 
     async fn setup(&self, system_info: &SystemInfo) -> Result<()> {
         install_valgrind(system_info).await?;
+
+        if let Err(error) = venv_compat::symlink_libpython(None) {
+            error!("Failed to symlink libpython: {}", error);
+        } else {
+            info!("Successfully added symlink for libpython in the venv");
+        }
+
         Ok(())
     }
 

src/run/runner/valgrind/helpers/mod.rs

@@ -1,3 +1,4 @@
 pub mod ignored_objects_path;
 pub mod introspected_nodejs;
 pub mod perf_maps;
+pub mod venv_compat;

src/run/runner/valgrind/helpers/venv_compat.rs

@@ -0,0 +1,119 @@
+use crate::prelude::*;
+use std::{io::Write, os::unix::fs::PermissionsExt, process::Command};
+
+/// When creating a virtual environment, only `python3` is symlinked or copied which makes
+/// lookups to `.venv/lib/libpython{version}.so.1.0` fail. This isn't an issue for most distributions
+/// since they use absolute paths in the `python3` executable.
+///
+/// However, uv uses relative paths which causes the lookups to fail:
+/// ```no_run
+/// > ldd .venv/bin/python3
+/// /home/project/.venv/bin/../lib/libpython3.13.so.1.0 => not found
+/// ```
+///
+/// The solution to this is to add the symlink of the `libpython` shared object in the
+/// virtual environment (`.venv/lib`) to make the symlink work correctly.
+///
+/// This scripts tries to find the virtual environment using `uv python find` and by finding the
+/// `python3` executable in the activated virtual environment.
+const VENV_COMPAT_SCRIPT: &str = r#"#!/usr/bin/env bash
+function add_symlink() {
+  local venv_python="$1"
+
+  system_python="$(readlink -f "$venv_python")"
+  if [ -z "$system_python" ]; then
+    echo "Error: Failed to resolve real path for $venv_python" >&2
+    return 1
+  fi
+
+  system_path="$(dirname $(dirname "$system_python"))"
+  venv_path="$(dirname $(dirname "$venv_python"))"
+  echo "Python installation (system): $system_path"
+  echo "Python installation (venv): $venv_path"
+
+  # Find libpython in the system python dir
+  mapfile -t libpython_array < <(find "$system_path" -maxdepth 3 -type f -name "libpython*.so.1.0" 2>/dev/null)
+  if [ ${#libpython_array[@]} -eq 0 ]; then
+      echo "Error: libpython*.so.1.0 not found in $system_path"
+      exit 1
+  fi
+
+  libpython="${libpython_array[0]}"
+  libpython_name=$(basename "$libpython")
+  echo "Found libpython: $libpython"
+
+  # Create the symlink in the virtual environment
+  venv_link="$venv_path/lib/$libpython_name"
+  if [ -e "$venv_link" ]; then
+    echo "Symlink already exists: $venv_link"
+  else
+    echo "Creating symlink: $venv_link -> $libpython"
+    ln -s "$libpython" "$venv_link"
+  fi
+}
+
+##
+##
+##
+
+uv_python="$(uv python find 2>/dev/null || true)"
+if [ -n "$uv_python" ]; then
+    add_symlink "$uv_python"
+else
+    echo "Didn't find uv venv, continuing..."
+fi
+
+##
+##
+##
+
+python3_path="$(which python3 2>/dev/null || true)"
+if [ -n "$python3_path" ]; then
+    echo "Found system Python: $python3_path"
+
+    if ldd "$python3_path" | grep -q "libpython.*not found"; then
+        add_symlink "$python3_path"
+    else
+        echo "System python is already correctly linked, continuing..."
+    fi
+fi
+"#;
+
+pub fn symlink_libpython(cwd: Option<&String>) -> anyhow::Result<()> {
+    let rwx = std::fs::Permissions::from_mode(0o777);
+    let mut script_file = tempfile::Builder::new()
+        .suffix(".sh")
+        .permissions(rwx)
+        .tempfile()?;
+    script_file.write_all(VENV_COMPAT_SCRIPT.as_bytes())?;
+
+    let mut cmd = Command::new("bash");
+    cmd.arg(script_file.path());
+
+    if let Some(cwd) = cwd {
+        cmd.current_dir(cwd);
+    }
+
+    debug!("Running the venv compat script");
+    let output = cmd.output()?;
+
+    let stdout = String::from_utf8(output.stdout)?;
+    debug!("Script output: {stdout}");
+
+    if !output.status.success() {
+        let stderr = String::from_utf8(output.stderr)?;
+        bail!("Failed to execute script: {stdout} {stderr}");
+    }
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_venv_compat_no_crash() {
+        assert!(symlink_libpython(None).is_ok());
+    }
+}