Advanced · Module 6 · Lesson 3 of 10
Signal Architecture and Delivery with sigaction
Intercept asynchronous software interrupts with sigaction, inspect kernel signal delivery frames, configure SA_RESTART and SA_SIGINFO, and eliminate signal race conditions.
By the end you can
- Configure reliable signal handlers using the POSIX sigaction interface
- Trace kernel signal frame injection, user-stack redirection, and sigreturn restoration
- Prevent unintended EINTR errors during blocking I/O using the SA_RESTART flag
- Extract sender identity and fault addresses using SA_SIGINFO and siginfo_t
Builds on Process Synchronization: wait, waitpid, and Zombie Reaping.
01 · A question first
Why did early Unix implementations of signal() reset handlers back to default behavior immediately upon invocation, leaving programs vulnerable to sudden death on rapid interrupts? And how does the kernel redirect your CPU registers to execute a signal handler without a thread switch?
Make a guess before you read on.
02 · The idea
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What's inside
- Start with the problem
- How the idea works
- Why it is correct
- What it costs
- Pitfalls and variations
- Where it is used
03 · Practice
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