sock_inet

socket_inet/Makefile

@@ -0,0 +1,19 @@
+CC ?= gcc
+CFLAGS ?= -Wall -g
+
+all: server.elf client.elf
+
+server.elf: server.c
+client.elf: client.c
+
+%.elf: %.c
+	@echo CC $@
+	@$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+test: all
+	bash test.sh
+
+clean:
+	rm -f *.elf *.o
+
+.PHONY: test clean

socket_inet/client.c

@@ -0,0 +1,54 @@
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#define MAX  80
+#define PORT 8080
+
+void func(int sockfd) {
+    char buff[MAX];
+
+    for (;;) {
+        char *msg = "Ping\n";
+        write(sockfd, msg, sizeof(buff));
+
+        bzero(buff, sizeof(buff));
+        read(sockfd, buff, sizeof(buff));
+
+        printf("From Server : %s", buff);
+        if ((strncmp(buff, "exit", 4)) == 0) {
+            printf("Client Exit...\n");
+            break;
+        }
+
+        exit(0);
+    }
+}
+
+int main() {
+    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (sockfd == -1) {
+        printf("socket creation failed...\n");
+        exit(0);
+    }
+    printf("Socket successfully created..\n");
+
+    struct sockaddr_in servaddr;
+    bzero(&servaddr, sizeof(servaddr));
+    servaddr.sin_family = AF_INET;
+    servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
+    servaddr.sin_port = htons(PORT);
+
+    if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0) {
+        printf("connection with the server failed...\n");
+        exit(0);
+    }
+
+    func(sockfd);
+    close(sockfd);
+}

socket_inet/server.c

@@ -0,0 +1,73 @@
+#include <netdb.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define MAX  80
+#define PORT 8080
+
+void func(int connfd) {
+    char buff[MAX];
+
+    for (;;) {
+        bzero(buff, MAX);
+
+        ssize_t recv_n = recv(connfd, buff, sizeof(buff), 0);
+        if (recv_n >= MAX) {
+            /* Likely more data, realloc */
+        }
+
+        buff[recv_n - 1] = '\0';
+        printf("From client: %s\n", buff);
+        bzero(buff, MAX);
+
+        char *msg = "Hello!\n";
+        send(connfd, msg, strlen(msg), 0);
+
+        if (strncmp("exit", buff, 4) == 0) {
+            printf("Server Exit...\n");
+            break;
+        }
+    }
+}
+
+int main() {
+    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (sockfd == -1) {
+        printf("socket creation failed...\n");
+        exit(0);
+    }
+
+    struct sockaddr_in servaddr;
+    bzero(&servaddr, sizeof(servaddr));
+
+    servaddr.sin_family = AF_INET;
+    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
+    servaddr.sin_port = htons(PORT);
+
+    if ((bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr))) != 0) {
+        printf("socket bind failed...\n");
+        exit(0);
+    }
+
+    if ((listen(sockfd, 5)) != 0) {
+        printf("Listen failed...\n");
+        exit(0);
+    }
+
+    struct sockaddr_in cli;
+    socklen_t          len = sizeof(cli);
+
+    int connfd = accept(sockfd, (struct sockaddr *)&cli, &len);
+    if (connfd < 0) {
+        printf("server accept failed...\n");
+        exit(0);
+    }
+
+    func(connfd);
+    close(sockfd);
+}

socket_inet/socket.c

@@ -0,0 +1,73 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#define SOCKET_PATH "/tmp/demosocket"
+#define BUF_SIZE    128
+
+int main(void) {
+    int                server_fd, client_fd;
+    struct sockaddr_un addr;
+    char               buf[BUF_SIZE];
+
+    // Clean up any leftover socket file
+    unlink(SOCKET_PATH);
+
+    // Create socket
+    server_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (server_fd == -1) {
+        perror("socket");
+        exit(EXIT_FAILURE);
+    }
+
+    // Zero out and set up the address structure
+    memset(&addr, 0, sizeof(addr));
+    addr.sun_family = AF_UNIX;
+    strncpy(addr.sun_path, SOCKET_PATH, sizeof(addr.sun_path) - 1);
+
+    // Bind the socket to the path
+    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+        perror("bind");
+        close(server_fd);
+        exit(EXIT_FAILURE);
+    }
+
+    // Listen for a connection
+    if (listen(server_fd, 1) == -1) {
+        perror("listen");
+        close(server_fd);
+        exit(EXIT_FAILURE);
+    }
+
+    printf("Server listening on %s...\n", SOCKET_PATH);
+
+    // Accept a connection
+    client_fd = accept(server_fd, NULL, NULL);
+    if (client_fd == -1) {
+        perror("accept");
+        close(server_fd);
+        exit(EXIT_FAILURE);
+    }
+
+    // Receive a message
+    ssize_t received = recv(client_fd, buf, BUF_SIZE - 1, 0);
+    if (received > 0) {
+        buf[received] = '\0';
+        printf("Received: %s", buf);
+
+        // Send a reply
+        const char *reply = "Got your message!\n";
+        send(client_fd, reply, strlen(reply), 0);
+    } else {
+        perror("recv");
+    }
+
+    // Clean up
+    close(client_fd);
+    close(server_fd);
+    unlink(SOCKET_PATH);
+    return 0;
+}

socket_inet/test.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+SOCKET_PATH="/tmp/demosocket"
+
+# Cleanup function to be run on exit
+cleanup() {
+    echo "Cleaning up..."
+    if [[ -n "$SERVER_PID" ]]; then
+        kill "$SERVER_PID" 2>/dev/null || true
+        wait "$SERVER_PID" 2>/dev/null || true
+    fi
+    rm -f "$SOCKET_PATH"
+}
+
+# Trap EXIT to ensure cleanup runs
+trap cleanup EXIT
+
+echo "Starting server..."
+./server.elf &
+SERVER_PID=$!
+
+# Wait briefly for the server to start
+sleep 0.2
+
+echo "Running client..."
+./client.elf