https://toorun.dev/tags/systems-programming/Recent content in systems-programming on toorun.devHugo -- gohugo.ioen-usSat, 25 Jul 2026 11:00:00 +0000https://toorun.dev/posts/linux-signals-ctrl-c-handler-sigint-sigalrm-sigusr1/Sat, 25 Jul 2026 11:00:00 +0000https://toorun.dev/posts/linux-signals-ctrl-c-handler-sigint-sigalrm-sigusr1/Linux Signals: Custom Ctrl+C Handler (Short Practical Guide) In Linux/embedded Linux, signals are useful for lightweight control events. Typical use: stop, reload, notify, timeout. This example shows: Custom Ctrl+C (SIGINT) behavior Sending SIGUSR1 to another process Using SIGALRM as a timeout Full short example #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #define W(msg) write(STDOUT_FILENO, msg, sizeof(msg) - 1) static volatile sig_atomic_t running = 1; static volatile sig_atomic_t got_usr1 = 0; static volatile sig_atomic_t child_pid = -1; static void on_sigint(int sig) { (void)sig; W("\nSIGINT: Ctrl+C caught.https://toorun.dev/posts/linux-ipc-embedded-linux-practical-guide/Sat, 25 Jul 2026 10:00:00 +0000https://toorun.dev/posts/linux-ipc-embedded-linux-practical-guide/Linux IPC in Embedded Systems (Short Practical Guide) IPC (Inter-Process Communication) lets processes exchange data and signals. In embedded Linux, IPC choice affects latency, memory use, complexity, and reliability. Quick selection Stream logs or simple producer->consumer: pipe / FIFO Request/response between local services: Unix domain socket Structured async messages with priorities: POSIX message queue High-throughput low-latency data path: shared memory + semaphore/mutex Simple notifications/events: signal or eventfd 1) Pipe/FIFO Best for Simple one-way byte stream Shell-like pipelines or parent-child communication Pros Very simple API Low overhead Cons Byte stream only (no message boundaries) Multi-writer design becomes messy // parent writes, child reads int fd[2]; pipe(fd); if (fork() == 0) { close(fd[1]); char buf[64] = {0}; read(fd[0], buf, sizeof(buf)); printf("child got: %s\n", buf); _exit(0); } close(fd[0]); write(fd[1], "hello", 5); 2) Unix Domain Socket (AF_UNIX) Best for Local client/server daemons Need bidirectional communication and framing Pros Faster than TCP loopback for local IPC Supports stream or datagram modes Can pass file descriptors (SCM_RIGHTS) Cons More setup than pipes Protocol framing is your responsibility // server side (minimal) int s = socket(AF_UNIX, SOCK_STREAM, 0); struct sockaddr_un addr = {.