See also: Kernel Index, Syscall, CPU

This directory provides signal-related infrastructure. Signal handling is currently in early development.

Components

Core Signal Handling

signal.c — Internal signal state management (early stage).

Signal Syscall Implementations

  • sigaction.c — sigaction syscall implementation

  • sigprocmask.c — sigprocmask syscall implementation

  • kill.c — kill syscall implementation

Architecture-Specific Signal Support

Located at kernel/arch/i686/signal/:

  • sigframe.c — Signal frame setup on the user stack

  • sigreturn_asm.S — Sigreturn trampoline assembly

Current Status

The signal infrastructure has source files in place but core signal delivery is not fully integrated with the scheduler and process lifecycle. The main signal.h header is mostly empty (include guard only). Key features still needed:

  • Pending signal queues per process

  • Signal delivery before returning to userspace

  • Proper signal mask handling in context switch

  • Integration with process lifecycle (exit, wait)

Typical Work in This Area

  • Complete POSIX-like signal behavior

  • Add pending queue and delivery edge-case handling

  • Improve interaction with process lifecycle and scheduler

  • Wire signal delivery into context switch path

Revision History

v2.0

Updated for v0.28: reflected actual state (infrastructure files exist but core delivery is incomplete)

v1.0

Initial signal subsystem summary