# SPDX-License-Identifier: GPL-3.0-or-later
"""ld_preload — userland rootkit / library-injection indicators.

Two signatures:
  * ``/etc/ld.so.preload`` non-empty: injects into *every* dynamically-linked
    process — the classic system-wide rootkit hook.
  * a process whose ``LD_PRELOAD`` points into a writable/temp dir — per-process
    function hooking (hiding files/procs, stealing credentials).
"""
from __future__ import annotations

from collections.abc import Iterator
from pathlib import Path

from ..alert import Alert, Severity
from ..config import Config
from ..system import SystemState

_SUSPICIOUS_PREFIXES = ("/tmp/", "/dev/shm/", "/var/tmp/", "/run/user/", "./")


def detect(state: SystemState, cfg: Config) -> Iterator[Alert]:
    preload = Path("/etc/ld.so.preload")
    try:
        contents = preload.read_text().strip() if preload.is_file() else ""
    except OSError:
        contents = ""
    if contents:
        yield Alert(
            severity=Severity.CRITICAL,
            signature="ld_preload",
            key="ldp:global",
            detail=f"/etc/ld.so.preload is non-empty: [{contents.replace(chr(10), ' ')}]",
        )

    for proc in state.processes:
        pre = proc.environ.get("LD_PRELOAD", "")
        if not pre:
            continue
        if pre.startswith(_SUSPICIOUS_PREFIXES):
            yield Alert(
                severity=Severity.CRITICAL,
                signature="ld_preload",
                key=f"ldp:{proc.pid}",
                detail=f"pid={proc.pid} comm={proc.comm} LD_PRELOAD=[{pre}]",
                pids=(proc.pid,),
            )