Add missing psmisc features: regexp/namespace filters for killall, fuser utility

[Copilot]

Implementation Plan for Missing Features in psmisc-rs

Phase 1: Missing faulx features ✅

• Add regexp support to faulx (killall)
  • Added -r, --regexp flag to interpret process names as regular expressions
  • Regex behind feature flag - can be disabled with --no-default-features
  • Supports case-insensitive matching when combined with -I, --ignore-case
  • Added unit tests for regex matching functionality
  • Updated faulx README to reflect completed feature
• Add namespace support to faulx (killall)
  • Added -n, --namespace option to match processes in the same namespace
  • Supports all Linux namespace types (pid, net, mnt, ipc, uts, cgroup, user, time)
  • Avoided clone - uses Option<&str> instead of Option<String> with lifetime parameter
  • Added unit tests for namespace checking
  • Updated faulx README to reflect completed feature

Phase 2: New utilities

• Implement fuser utility (identify processes using files/sockets) ✅
  • Created new fuser crate with full implementation
  • Checks current working directory, root directory, executable, file descriptors, and memory maps
  • Supports kill functionality with custom signals
  • Verbose and quiet modes
  • Avoided clones - uses Arc<str> for shared process names
  • Updated main README to list fuser as implemented
  • All code review feedback addressed:
    • Moved signal parsing to helpers crate to eliminate duplication
    • Removed unused CLI flags
    • Optimized PID tracking with HashSet (O(1) vs O(n) lookup)
    • Fixed memory map parsing to handle all line formats and process all entries
    • Improved code readability in time checking logic
    • Fixed all redundant clone warnings

Architecture & Standards ✅

• Follow existing code patterns and structure
• Add tests for new features
• Update documentation
• Ensure clippy and formatting compliance
• Address all code review feedback
• Rebased to main - includes latest test coverage improvements

All requested changes complete:

• ✅ Regex behind feature flag
• ✅ Clones avoided (lifetimes + Arc)
• ✅ Rebased to main

Original prompt

Identify and implement the missing features in the martabal/psmisc-rs repository based on the project specifications or roadmap. Ensure that the new features align with the current architecture and meet the repository's standards. Deliver well-documented code with necessary tests for the new features.

This pull request was created as a result of the following prompt from Copilot chat.

Identify and implement the missing features in the martabal/psmisc-rs repository based on the project specifications or roadmap. Ensure that the new features align with the current architecture and meet the repository's standards. Deliver well-documented code with necessary tests for the new features.

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[martabal]

@copilot put regex behind a feature flag, avoid clone if you can

[martabal]

@copilot Retry my last comment and rebase to main

[Copilot]

@copilot Retry my last comment and rebase to main

Completed both tasks:

1. Regex behind feature flag - Regex support is now optional, enabled by default. Can be disabled with --no-default-features when building faulx. The regex import and related functions are wrapped in #[cfg(feature = "regex")].

2. Avoided clones:

   • In faulx: Changed OptionsPids to use Option<&'a str> instead of Option<String> for namespace field, eliminating the clone in main.rs
   • In fuser: Changed ProcessFileInfo.comm from String to Arc<str>, allowing cheap reference counting instead of cloning strings for each file access type

3. Rebased to main - Successfully rebased onto latest main (commits a7b2e88 and 2cb0682), resolving all conflicts

The branch is ready but I encountered authentication issues when trying to force-push the rebased commits. The local branch has all changes applied and passes all tests and clippy checks.