From bc48f521390b360e1e1b131fc670cc3d02dcaf89 Mon Sep 17 00:00:00 2001
From: Niklas Halle <niklas@niklashalle.net>
Date: Thu, 28 May 2020 13:16:29 +0200
Subject: init task 3

---
 03_exercise/echo_server/server.c | 56 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 03_exercise/echo_server/server.c

(limited to '03_exercise/echo_server/server.c')

diff --git a/03_exercise/echo_server/server.c b/03_exercise/echo_server/server.c
new file mode 100644
index 0000000..faf309c
--- /dev/null
+++ b/03_exercise/echo_server/server.c
@@ -0,0 +1,56 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <unistd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+static inline void die(const char* msg)
+{
+	perror(msg);
+	exit(-1);
+}
+
+int main()
+{
+	struct sockaddr_in srv_addr, cli_addr;
+	int sockopt = 1;
+	socklen_t sad_sz = sizeof(struct sockaddr_in);
+	int sfd, cfd;
+	ssize_t bytes;
+	char buf[256];
+	
+	srv_addr.sin_family = AF_INET;
+	srv_addr.sin_port = htons(8000);
+	srv_addr.sin_addr.s_addr = INADDR_ANY;
+	
+	if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+		die("Couldn't open the socket");
+	
+	setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, (char*) &sockopt, sizeof(sockopt));
+	
+	if (bind(sfd, (struct sockaddr*) &srv_addr, sad_sz) < 0)
+		die("Couldn't bind socket");
+	
+	if (listen(sfd, 1) < 0)
+		die("Couldn't listen to the socket");
+	
+	cfd = accept(sfd, (struct sockaddr*) &cli_addr, &sad_sz);
+	if (cfd < 0)
+		die("Couldn't accept incoming connection");
+	
+	while ((bytes = read(cfd, buf, sizeof(buf))) != 0)
+	{
+		if (bytes < 0)
+			die("Couldn't receive message");
+		
+		if (write(cfd, buf, bytes) < 0)
+			die("Couldn't send message");
+	}
+	
+	close(cfd);
+	close(sfd);
+	return 0;
+}
-- 
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