examples

commit 44dc0f57e75e875fc0907b5e0afd6d936ca682d1
parent 78e7d57d4b5f79651731d3a16ecf4e5a37b9d70b
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Wed, 10 Aug 2022 16:49:54 +0100

epoll: Generalize event-loop example

Diffstat:
A
src/epoll.c
 | 
101
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
D
src/timerfd.c
 | 
82
-------------------------------------------------------------------------------

2 files changed, 101 insertions(+), 82 deletions(-)
diff --git a/src/epoll.c b/src/epoll.c
@@ -0,0 +1,101 @@
+#include <sys/epoll.h>
+#include <sys/timerfd.h>
+#include <sys/signalfd.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <err.h>
+#include <errno.h>
+
+static int timer, signals, event_queue;
+
+static void check_err(char const* msg)
+{
+	if (errno)
+		err(1, msg);
+}
+
+static void stdin_event(void)
+{
+	char buf[64];
+	int n = read(STDIN_FILENO, buf, sizeof buf - 1);
+
+	if (n <= 0)
+	{
+		puts("Stdin closed.");
+		exit(0);
+	}
+	for (int i = 0; i < n; ++i)
+		if (iscntrl(buf[i]))
+			buf[i] = '.';
+	buf[n] = '\0';
+
+	printf("Stdin: '%s'\n", buf);
+}
+
+static void timerfd_event(void)
+{
+	static uint64_t ticks;
+	uint64_t new_ticks;
+	read(timer, &new_ticks, sizeof new_ticks);
+	ticks += new_ticks;
+	printf("Tick: +%lu %lu\n", new_ticks, ticks);
+}
+
+static void signalfd_event(void)
+{
+	struct signalfd_siginfo buf;
+	read(signals, &buf, sizeof buf);
+	check_err("read");
+	printf("Signal: %s\n", strsignal(buf.ssi_signo));
+}
+
+static void add_epollin(int fd, void(*cb)())
+{
+	epoll_ctl(event_queue, EPOLL_CTL_ADD, fd, &(struct epoll_event){
+               .events = EPOLLIN,
+               .data.ptr = cb,
+        });
+	check_err("epoll_ctl");
+}
+
+int main()
+{
+	timer = timerfd_create(CLOCK_MONOTONIC, 0);
+	check_err("timerfd_create");
+	timerfd_settime(timer, 0, &(struct itimerspec){
+               .it_interval = {1, 0},  /* Interval for periodic timer */
+               .it_value = {1, 0},     /* Initial expiration */
+        }, NULL);
+	check_err("timerfd_settime");
+
+	sigset_t sigset;
+	sigemptyset(&sigset);
+	check_err("sigemptyset");
+	sigaddset(&sigset, SIGINT);
+	check_err("sigaddset");
+	sigprocmask(SIG_SETMASK, &sigset, NULL);
+	check_err("sigprocmask");
+	signals = signalfd(-1, &sigset, 0);
+	check_err("signalfd");
+
+	event_queue = epoll_create1(0);
+	check_err("epoll_create2");
+	add_epollin(STDIN_FILENO, stdin_event);
+	add_epollin(timer, timerfd_event);
+	add_epollin(signals, signalfd_event);
+
+	for (;;)
+	{
+		struct epoll_event events[8];
+		int n_events = epoll_wait(event_queue, events, sizeof events / sizeof *events, -1);
+		check_err("epoll_wait");
+
+		for (int i = 0; i < n_events; ++i)
+			((void(*)(void))events[i].data.ptr)();
+	}
+}
diff --git a/src/timerfd.c b/src/timerfd.c
@@ -1,82 +0,0 @@
-#include <sys/epoll.h>
-#include <sys/timerfd.h>
-#include <unistd.h>
-#include <stdio.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <ctype.h>
-
-static int timer, event_queue;
-
-static void succeed_or_die(int n, char const* msg)
-{
-	if (n >= 0)
-		return;
-
-	perror(msg);
-	exit(1);
-}
-
-static void stdin_event(void)
-{
-	char buf[64];
-	int n = read(STDIN_FILENO, buf, sizeof buf - 1);
-
-	if (n <= 0)
-	{
-		puts("Stdin closed.");
-		exit(0);
-	}
-	for (int i = 0; i < n; ++i)
-		if (iscntrl(buf[i]))
-			buf[i] = '.';
-	buf[n] = '\0';
-
-	printf("Stdin: '%s'\n", buf);
-}
-
-static void timerfd_event(void)
-{
-	static uint64_t ticks;
-	uint64_t new_ticks;
-	read(timer, &new_ticks, sizeof new_ticks);
-	ticks += new_ticks;
-	printf("Tick +%lu %lu\n", new_ticks, ticks);
-}
-
-int main()
-{
-	timer = timerfd_create(CLOCK_MONOTONIC, 0);
-	succeed_or_die(timer, "timerfd_create");
-
-	int res = timerfd_settime(timer, 0, &(struct itimerspec){
-               .it_interval = {1, 0},  /* Interval for periodic timer */
-               .it_value = {1, 0},     /* Initial expiration */
-        }, NULL);
-	succeed_or_die(res, "timerfd_settime");
-
-	event_queue = epoll_create1(0);
-	succeed_or_die(event_queue, "epoll_create2");
-
-	res = epoll_ctl(event_queue, EPOLL_CTL_ADD, STDIN_FILENO, &(struct epoll_event){
-               .events = EPOLLIN,
-               .data.ptr = stdin_event,
-        });
-	succeed_or_die(res, "epoll_ctl");
-
-	res = epoll_ctl(event_queue, EPOLL_CTL_ADD, timer, &(struct epoll_event){
-               .events = EPOLLIN,
-               .data.ptr = timerfd_event,
-        });
-	succeed_or_die(res, "epoll_ctl");
-
-	for (;;)
-	{
-		struct epoll_event events[8];
-		int n_events = epoll_wait(event_queue, events, sizeof events / sizeof *events, -1);
-		succeed_or_die(n_events, "epoll_wait");
-
-		for (int i = 0; i < n_events; ++i)
-			((void(*)(void))events[i].data.ptr)();
-	}
-}