joule-profiler-core 1.0.1

Core library for joule-profiler, handling orchestration and energy measurements
Documentation 
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use std::{
    env,
    fs::{self, File, OpenOptions, Permissions},
    os::unix::fs::{MetadataExt, PermissionsExt, chown},
    path::{Path, PathBuf},
};

use crate::util::time::get_timestamp_micros;

/// Get the absolute path of a file.
pub fn get_absolute_path(filename: &str) -> Result<String, std::io::Error> {
    let path = PathBuf::from(filename);
    let absolute_path = if path.is_absolute() {
        path
    } else {
        env::current_dir()?.join(path)
    };

    Ok(absolute_path.display().to_string())
}

/// Generates a default filename for results data.
pub fn default_results_filename(ext: &str) -> String {
    format!("data{}.{}", get_timestamp_micros(), ext)
}

const URW_GRW_OR_PERMS: u32 = 0o664;

/// Creates a file at `path`, ensuring it is owned by the parent directory's owner.
///
/// When running as root, the file ownership is set to match the parent directory
/// (via `chown`) so the file isn't accidentally left owned by root.
/// The `getuid()` call is safe, it has no preconditions and always succeeds.
pub fn create_file_with_user_permissions(path: &str) -> std::io::Result<File> {
    let file = OpenOptions::new()
        .write(true)
        .create(true)
        .truncate(true)
        .open(path)?;
    file.set_permissions(Permissions::from_mode(URW_GRW_OR_PERMS))?;

    if unsafe { libc::getuid() } == 0 {
        let parent = Path::new(path).parent().unwrap_or_else(|| Path::new("."));
        let meta = fs::metadata(parent)?;
        chown(path, Some(meta.uid()), Some(meta.gid()))?;
    }

    Ok(file)
}