From c446378817e4d215ffd69f452f846fc5278f7943 Mon Sep 17 00:00:00 2001
From: cflip <cflip@cflip.net>
Date: Sun, 9 Jul 2023 11:57:13 -0600
Subject: Gracefully shut down server when interrupted with Ctrl+C

---
 cfws.c | 16 ++++++++++++++--
 net.c  | 16 ++++++++++++----
 net.h  |  2 +-
 3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/cfws.c b/cfws.c
index f280fe4..2e8eb32 100644
--- a/cfws.c
+++ b/cfws.c
@@ -11,14 +11,24 @@
 
 #define CFWS_DEFAULT_PORT 8080
 
+static int serverfd;
+
 static void handle_request(const struct http_request *, int);
 
+static void handle_sigint(int signum)
+{
+	(void)signum;
+	shutdown(serverfd, SHUT_RDWR);
+}
+
 int main(int argc, char *argv[])
 {
 	int port = CFWS_DEFAULT_PORT;
-	int serverfd, clientfd;
+	int clientfd;
 	struct http_request request;
 
+	signal(SIGINT, handle_sigint);
+
 	/* Prevent the program from quitting if it attempts to write to a closed
 	 * socket. */
 	signal(SIGPIPE, SIG_IGN);
@@ -30,7 +40,9 @@ int main(int argc, char *argv[])
 	printf("Serving a directory at localhost:%d\n", port);
 
 	while (1) {
-		request = net_next_request(serverfd, &clientfd);
+		int rc = net_next_request(serverfd, &clientfd, &request);
+		if (rc != 0)
+			break;
 
 		handle_request(&request, clientfd);
 
diff --git a/net.c b/net.c
index 84d713b..438abcb 100644
--- a/net.c
+++ b/net.c
@@ -1,6 +1,7 @@
 #include "net.h"
 
 #include <arpa/inet.h>
+#include <errno.h>
 #include <netdb.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -50,19 +51,26 @@ int net_init_server(int port)
 	return sockfd;
 }
 
-struct http_request net_next_request(int serverfd, int *clientfd)
+int net_next_request(int serverfd, int *clientfd, struct http_request *req)
 {
 	int connfd;
 	char readbuf[CFWS_NET_MAXREAD];
-	struct http_request req;
 
 	connfd = accept(serverfd, NULL, NULL);
+	if (connfd == -1) {
+		/* EINVAL most likely indicates that the server socket was
+		 * closed due to the user pressing Ctrl+C. */
+		if (errno == EINVAL)
+			return 1;
+		perror("cfws: accept");
+		return -1;
+	}
 
 	/* Read and parse the HTTP request */
 	memset(readbuf, 0, CFWS_NET_MAXREAD);
 	read(connfd, readbuf, CFWS_NET_MAXREAD - 1);
-	req = http_parse_request(readbuf);
+	*req = http_parse_request(readbuf);
 
 	*clientfd = connfd;
-	return req;
+	return 0;
 }
diff --git a/net.h b/net.h
index 92f61c4..481f520 100644
--- a/net.h
+++ b/net.h
@@ -7,6 +7,6 @@
 #include "http.h"
 
 int net_init_server(int);
-struct http_request net_next_request(int serverfd, int *clientfd);
+int net_next_request(int serverfd, int *clientfd, struct http_request *);
 
 #endif
-- 
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