libsalus 0.1.1

// Copyright (c) 2025 salus developers
//
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. All files in the project carrying such notice may not be copied,
// modified, or distributed except according to those terms.

//! Salus - A secure secret store in Rust

// rustc lints
#![cfg_attr(
    all(feature = "unstable", nightly),
    feature(
        multiple_supertrait_upcastable,
        must_not_suspend,
        non_exhaustive_omitted_patterns_lint,
        strict_provenance_lints,
        unqualified_local_imports,
    )
)]
#![cfg_attr(nightly, allow(single_use_lifetimes))]
#![cfg_attr(
    nightly,
    deny(
        absolute_paths_not_starting_with_crate,
        ambiguous_glob_imports,
        ambiguous_glob_reexports,
        ambiguous_negative_literals,
        ambiguous_wide_pointer_comparisons,
        anonymous_parameters,
        array_into_iter,
        asm_sub_register,
        async_fn_in_trait,
        bad_asm_style,
        bare_trait_objects,
        boxed_slice_into_iter,
        break_with_label_and_loop,
        clashing_extern_declarations,
        closure_returning_async_block,
        coherence_leak_check,
        confusable_idents,
        const_evaluatable_unchecked,
        const_item_mutation,
        dangling_pointers_from_temporaries,
        dead_code,
        dependency_on_unit_never_type_fallback,
        deprecated,
        deprecated_in_future,
        deprecated_safe_2024,
        deprecated_where_clause_location,
        deref_into_dyn_supertrait,
        deref_nullptr,
        double_negations,
        drop_bounds,
        dropping_copy_types,
        dropping_references,
        duplicate_macro_attributes,
        dyn_drop,
        edition_2024_expr_fragment_specifier,
        elided_lifetimes_in_paths,
        ellipsis_inclusive_range_patterns,
        explicit_outlives_requirements,
        exported_private_dependencies,
        ffi_unwind_calls,
        forbidden_lint_groups,
        forgetting_copy_types,
        forgetting_references,
        for_loops_over_fallibles,
        function_item_references,
        hidden_glob_reexports,
        if_let_rescope,
        impl_trait_overcaptures,
        impl_trait_redundant_captures,
        improper_ctypes,
        improper_ctypes_definitions,
        inline_no_sanitize,
        internal_features,
        invalid_from_utf8,
        invalid_macro_export_arguments,
        invalid_nan_comparisons,
        invalid_value,
        irrefutable_let_patterns,
        keyword_idents_2018,
        keyword_idents_2024,
        large_assignments,
        late_bound_lifetime_arguments,
        legacy_derive_helpers,
        let_underscore_drop,
        macro_use_extern_crate,
        map_unit_fn,
        meta_variable_misuse,
        mismatched_lifetime_syntaxes,
        missing_abi,
        missing_copy_implementations,
        missing_debug_implementations,
        missing_docs,
        missing_unsafe_on_extern,
        mixed_script_confusables,
        named_arguments_used_positionally,
        never_type_fallback_flowing_into_unsafe,
        no_mangle_generic_items,
        non_ascii_idents,
        non_camel_case_types,
        non_contiguous_range_endpoints,
        non_fmt_panics,
        non_local_definitions,
        non_shorthand_field_patterns,
        non_snake_case,
        non_upper_case_globals,
        noop_method_call,
        opaque_hidden_inferred_bound,
        out_of_scope_macro_calls,
        overlapping_range_endpoints,
        path_statements,
        private_bounds,
        private_interfaces,
        ptr_to_integer_transmute_in_consts,
        redundant_imports,
        redundant_lifetimes,
        redundant_semicolons,
        refining_impl_trait_internal,
        refining_impl_trait_reachable,
        renamed_and_removed_lints,
        rust_2021_incompatible_closure_captures,
        rust_2021_incompatible_or_patterns,
        rust_2021_prefixes_incompatible_syntax,
        rust_2021_prelude_collisions,
        rust_2024_guarded_string_incompatible_syntax,
        rust_2024_incompatible_pat,
        rust_2024_prelude_collisions,
        self_constructor_from_outer_item,
        semicolon_in_expressions_from_macros,
        single_use_lifetimes,
        special_module_name,
        stable_features,
        static_mut_refs,
        suspicious_double_ref_op,
        tail_expr_drop_order,
        trivial_bounds,
        trivial_casts,
        trivial_numeric_casts,
        type_alias_bounds,
        tyvar_behind_raw_pointer,
        uncommon_codepoints,
        unconditional_recursion,
        uncovered_param_in_projection,
        unexpected_cfgs,
        unfulfilled_lint_expectations,
        ungated_async_fn_track_caller,
        uninhabited_static,
        unit_bindings,
        unknown_lints,
        unknown_or_malformed_diagnostic_attributes,
        unnameable_test_items,
        unnameable_types,
        unpredictable_function_pointer_comparisons,
        unreachable_code,
        unreachable_patterns,
        unreachable_pub,
        unsafe_attr_outside_unsafe,
        unsafe_code,
        unsafe_op_in_unsafe_fn,
        unstable_name_collisions,
        unstable_syntax_pre_expansion,
        unused_allocation,
        unused_assignments,
        unused_associated_type_bounds,
        unused_attributes,
        unused_braces,
        unused_comparisons,
        unused_crate_dependencies,
        unused_doc_comments,
        unused_extern_crates,
        unused_features,
        unused_import_braces,
        unused_imports,
        unused_labels,
        unused_lifetimes,
        unused_macro_rules,
        unused_macros,
        unused_must_use,
        unused_mut,
        unused_parens,
        unused_qualifications,
        unused_results,
        unused_unsafe,
        unused_variables,
        useless_ptr_null_checks,
        uses_power_alignment,
        variant_size_differences,
        while_true,
    )
)]
// If nightly and unstable, allow `incomplete_features` and `unstable_features`
#![cfg_attr(
    all(feature = "unstable", nightly),
    allow(incomplete_features, unstable_features)
)]
// If nightly and not unstable, deny `incomplete_features` and `unstable_features`
#![cfg_attr(
    all(not(feature = "unstable"), nightly),
    deny(incomplete_features, unstable_features)
)]
// The unstable lints
#![cfg_attr(
    all(feature = "unstable", nightly),
    deny(
        fuzzy_provenance_casts,
        lossy_provenance_casts,
        multiple_supertrait_upcastable,
        must_not_suspend,
        non_exhaustive_omitted_patterns,
        unqualified_local_imports,
    )
)]
// clippy lints
#![cfg_attr(nightly, deny(clippy::all, clippy::pedantic))]
// rustdoc lints
#![cfg_attr(
    nightly,
    deny(
        rustdoc::bare_urls,
        rustdoc::broken_intra_doc_links,
        rustdoc::invalid_codeblock_attributes,
        rustdoc::invalid_html_tags,
        rustdoc::missing_crate_level_docs,
        rustdoc::private_doc_tests,
        rustdoc::private_intra_doc_links,
    )
)]
#![cfg_attr(all(docsrs), feature(doc_cfg))]

use std::path::PathBuf;

use anyhow::Result;
use interprocess::local_socket::GenericFilePath;
use interprocess::local_socket::Name;
use interprocess::local_socket::ToFsName;

mod key;
mod message;

pub use crate::key::gen_shares;
pub use crate::key::unlock_key;
pub use crate::message::Action;
pub use crate::message::Init;
pub use crate::message::MAX_MESSAGE_SIZE;
pub use crate::message::MAX_UNLOCK_SECONDS;
pub use crate::message::Response;
pub use crate::message::Share;
pub use crate::message::Shares;
pub use crate::message::Store;
pub use crate::message::UnlockTimeout;
pub use crate::message::agent::AgentAction;
pub use crate::message::agent::AgentResponse;
pub use crate::message::agent::SetInfo;
pub use crate::message::decode;
pub use crate::message::encode;
use interprocess::local_socket::GenericNamespaced;
use interprocess::local_socket::NameType;
use interprocess::local_socket::ToNsName;
pub use ssss::SsssConfig;

/// The base file name used for the daemon IPC socket.
const SOCKET_FILE_NAME: &str = "salus.sock";

/// The base file name used for the `salus-agent` IPC socket.
const AGENT_SOCKET_FILE_NAME: &str = "salus-agent.sock";

/// The environment variable, shared by both the daemon and the client, that
/// overrides the IPC socket location. Resolving it inside this crate keeps the
/// two processes in sync from a single setting.
const SOCKET_ENV: &str = "SALUS_SOCKET";

/// The environment variable, shared by the agent and the client, that overrides
/// the `salus-agent` IPC socket location.
const AGENT_SOCKET_ENV: &str = "SALUS_AGENT_SOCKET";

/// Where the IPC socket lives once resolved.
#[derive(Clone, Debug, Eq, PartialEq)]
enum SocketTarget {
    /// A namespaced socket addressed by a bare name (e.g. the Linux abstract
    /// namespace), used by default where the platform supports it.
    Namespaced(String),
    /// A filesystem socket addressed by path, used for explicit overrides and
    /// as the fallback on platforms without namespaced socket support.
    File(PathBuf),
}

/// Resolve where an IPC socket should live.
///
/// Precedence: an explicit per-side override wins, then the shared environment
/// value, then a platform default (a namespaced name where supported, otherwise
/// a file under the runtime/temp directory). `default_name` is the base socket
/// file name used for both the namespaced name and the file fallback.
fn socket_target(
    override_path: Option<&str>,
    env_socket: Option<&str>,
    default_name: &str,
) -> SocketTarget {
    if let Some(path) = override_path.or(env_socket) {
        SocketTarget::File(PathBuf::from(path))
    } else if GenericNamespaced::is_supported() {
        SocketTarget::Namespaced(default_name.to_string())
    } else {
        let dir = dirs2::runtime_dir().unwrap_or_else(std::env::temp_dir);
        SocketTarget::File(dir.join(default_name))
    }
}

/// Turn a resolved [`SocketTarget`] into an interprocess [`Name`].
fn target_to_name<'a>(target: SocketTarget) -> Result<Name<'a>> {
    let name = match target {
        SocketTarget::Namespaced(name) => name.to_ns_name::<GenericNamespaced>()?,
        SocketTarget::File(path) => path.to_fs_name::<GenericFilePath>()?,
    };
    Ok(name)
}

/// Get the socket name used for daemon interprocess communication.
///
/// `override_path`, when `Some`, is an explicit socket path supplied by the
/// caller (CLI flag or config file) and takes precedence over the shared
/// `SALUS_SOCKET` environment variable and the platform default.
///
/// # Errors
///
/// * An error can be thrown if the socket name cannot be created.
///
pub fn socket_name<'a>(override_path: Option<&str>) -> Result<Name<'a>> {
    let env_socket = std::env::var(SOCKET_ENV).ok();
    target_to_name(socket_target(
        override_path,
        env_socket.as_deref(),
        SOCKET_FILE_NAME,
    ))
}

/// Get the socket name used to talk to the `salus-agent`.
///
/// Mirrors [`socket_name`] but resolves the agent-specific override, the shared
/// `SALUS_AGENT_SOCKET` environment variable, and the agent's platform default,
/// so the agent and client always agree on a single location.
///
/// # Errors
///
/// * An error can be thrown if the socket name cannot be created.
///
pub fn agent_socket_name<'a>(override_path: Option<&str>) -> Result<Name<'a>> {
    let env_socket = std::env::var(AGENT_SOCKET_ENV).ok();
    target_to_name(socket_target(
        override_path,
        env_socket.as_deref(),
        AGENT_SOCKET_FILE_NAME,
    ))
}

#[cfg(test)]
mod test {
    use std::path::PathBuf;

    use super::{
        AGENT_SOCKET_FILE_NAME, SOCKET_FILE_NAME, SocketTarget, agent_socket_name, socket_name,
        socket_target, target_to_name,
    };

    #[test]
    fn override_wins_over_env() {
        let target = socket_target(
            Some("/tmp/override.sock"),
            Some("/tmp/env.sock"),
            SOCKET_FILE_NAME,
        );
        assert_eq!(
            target,
            SocketTarget::File(PathBuf::from("/tmp/override.sock"))
        );
    }

    #[test]
    fn env_used_when_no_override() {
        let target = socket_target(None, Some("/tmp/env.sock"), SOCKET_FILE_NAME);
        assert_eq!(target, SocketTarget::File(PathBuf::from("/tmp/env.sock")));
    }

    #[test]
    fn default_used_when_nothing_configured() {
        // With neither an override nor the env var set, the default depends on
        // platform support: a bare namespaced name, or a file under the
        // runtime/temp directory. Either way it must end with the base name.
        match socket_target(None, None, SOCKET_FILE_NAME) {
            SocketTarget::Namespaced(name) => assert_eq!(name, SOCKET_FILE_NAME),
            SocketTarget::File(path) => {
                assert_eq!(path.file_name().unwrap(), SOCKET_FILE_NAME);
            }
        }
    }

    #[test]
    fn agent_default_uses_agent_base_name() {
        // The agent default must resolve to the agent base name, not the
        // daemon's, so the two sockets never collide.
        match socket_target(None, None, AGENT_SOCKET_FILE_NAME) {
            SocketTarget::Namespaced(name) => assert_eq!(name, AGENT_SOCKET_FILE_NAME),
            SocketTarget::File(path) => {
                assert_eq!(path.file_name().unwrap(), AGENT_SOCKET_FILE_NAME);
            }
        }
    }

    #[test]
    fn target_to_name_builds_namespaced_and_file() {
        assert!(target_to_name(SocketTarget::Namespaced(SOCKET_FILE_NAME.to_string())).is_ok());
        assert!(target_to_name(SocketTarget::File(PathBuf::from("/tmp/x.sock"))).is_ok());
    }

    #[test]
    fn socket_name_with_override_resolves() {
        assert!(socket_name(Some("/tmp/override.sock")).is_ok());
        assert!(agent_socket_name(Some("/tmp/agent-override.sock")).is_ok());
    }
}