From 81757c235ff8e112b4baabdd1ff23409426e9c98 Mon Sep 17 00:00:00 2001
From: Philip Wittamore <philip@wittamore.com>
Date: Sun, 8 Jun 2025 22:00:43 +0200
Subject: update

---
 src/signal-handler.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 src/signal-handler.c

(limited to 'src/signal-handler.c')

diff --git a/src/signal-handler.c b/src/signal-handler.c
new file mode 100644
index 0000000..d816dcd
--- /dev/null
+++ b/src/signal-handler.c
@@ -0,0 +1,124 @@
+#include "signal-handler.h"
+
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/signalfd.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "block.h"
+#include "main.h"
+#include "timer.h"
+
+typedef struct signalfd_siginfo signal_info;
+
+signal_handler signal_handler_new(
+    block *const blocks, const unsigned short block_count,
+    const signal_refresh_callback refresh_callback,
+    const signal_timer_callback timer_callback) {
+    signal_handler handler = {
+        .refresh_callback = refresh_callback,
+        .timer_callback = timer_callback,
+
+        .blocks = blocks,
+        .block_count = block_count,
+    };
+
+    return handler;
+}
+
+int signal_handler_init(signal_handler *const handler) {
+    signal_set set;
+    (void)sigemptyset(&set);
+
+    // Handle user-generated signal for refreshing the status.
+    (void)sigaddset(&set, REFRESH_SIGNAL);
+
+    // Handle SIGALRM generated by the timer.
+    (void)sigaddset(&set, TIMER_SIGNAL);
+
+    // Handle termination signals.
+    (void)sigaddset(&set, SIGINT);
+    (void)sigaddset(&set, SIGTERM);
+
+    for (unsigned short i = 0; i < handler->block_count; ++i) {
+        const block *const block = &handler->blocks[i];
+        if (block->signal > 0) {
+            if (sigaddset(&set, SIGRTMIN + block->signal) != 0) {
+                (void)fprintf(
+                    stderr,
+                    "error: invalid or unsupported signal specified for "
+                    "\"%s\" block\n",
+                    block->command);
+                return 1;
+            }
+        }
+    }
+
+    // Create a signal file descriptor for epoll to watch.
+    handler->fd = signalfd(-1, &set, 0);
+    if (handler->fd == -1) {
+        (void)fprintf(stderr,
+                      "error: could not create file descriptor for signals\n");
+        return 1;
+    }
+
+    // Block all realtime and handled signals.
+    for (int i = SIGRTMIN; i <= SIGRTMAX; ++i) {
+        (void)sigaddset(&set, i);
+    }
+    (void)sigprocmask(SIG_BLOCK, &set, NULL);
+
+    return 0;
+}
+
+int signal_handler_deinit(signal_handler *const handler) {
+    if (close(handler->fd) != 0) {
+        (void)fprintf(stderr,
+                      "error: could not close signal file descriptor\n");
+        return 1;
+    }
+
+    return 0;
+}
+
+int signal_handler_process(signal_handler *const handler, timer *const timer) {
+    signal_info info;
+    const ssize_t bytes_read = read(handler->fd, &info, sizeof(info));
+    if (bytes_read == -1) {
+        (void)fprintf(stderr, "error: could not read info of incoming signal");
+        return 1;
+    }
+
+    const int signal = (int)info.ssi_signo;
+    switch (signal) {
+        case TIMER_SIGNAL:
+            if (handler->timer_callback(handler->blocks, handler->block_count,
+                                        timer) != 0) {
+                return 1;
+            }
+            return 0;
+        case REFRESH_SIGNAL:
+            if (handler->refresh_callback(handler->blocks,
+                                          handler->block_count) != 0) {
+                return 1;
+            }
+            return 0;
+        case SIGTERM:
+            // fall through
+        case SIGINT:
+            return 1;
+    }
+
+    for (unsigned short i = 0; i < handler->block_count; ++i) {
+        block *const block = &handler->blocks[i];
+        if (block->signal == signal - SIGRTMIN) {
+            const uint8_t button = (uint8_t)info.ssi_int;
+            block_execute(block, button);
+            break;
+        }
+    }
+
+    return 0;
+}
-- 
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