Create multiclient-client.c

multiclient-client.c

@@ -0,0 +1,103 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <netinet/in.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>  //For gethostbyname function
+
+void error(char* msg){
+    perror(msg);
+    exit(1);
+}
+
+int read_image_file(char *file_name, char **buffer, int *sizeof_buffer) {
+    int c, i;
+    int char_read = 0;
+    FILE* fp = fopen(file_name, "rb");
+
+    if (fp == NULL) {
+        fprintf(stderr, "\t Can't open file : %s", file_name);
+        return -1;
+    }
+
+    fseek(fp, 0L, SEEK_END);
+    *sizeof_buffer = ftell(fp);
+    fseek(fp, 0L, SEEK_SET);
+    *buffer = (char *)malloc(*sizeof_buffer);
+    fread(*buffer, *sizeof_buffer, 1, fp);
+    return 0;
+}
+
+int send_to_server(int sockfd, void *buffer, int size) {
+    int n = write(sockfd, buffer, size);    //Write to server
+
+    if (n < 0) {
+        error("\t Error writing to server\n");
+        free(buffer);
+    }
+    return n;
+}
+
+void client_func(void *arg)
+{	
+   	char** argv = (char** )arg; 
+    int sockfd, portno, n;  //File descriptor for Sockets
+    char *buffer = NULL;   //Temporary buffer to read and write data
+    int size_of_file;
+
+    struct sockaddr_in serv_addr;   //Structure to hold Server and Client details
+    struct hostent* server;
+    int len;
+    char reply[1024];
+
+	  server = gethostbyname(argv[1]);
+    portno = atoi(argv[2]);
+
+    sockfd = socket(AF_INET, SOCK_STREAM, 0);   //AF_INET refers to addresses from the internet, IP addresses specifically. SOCK_STREAM to refer TCP(SOCK_DGRAM for UDP), 0 again for TCP
+    if(sockfd<0){
+        error("Socket failed \n");
+    }
+
+
+    if(server == NULL){
+        error("No such host\n");
+    }
+
+    bzero((char*) &serv_addr, sizeof(serv_addr));   //Empty contents of serv_addr
+    serv_addr.sin_family = AF_INET; //Assign IPv4 family to server_address
+    bcopy((char*) server->h_addr, (char*) &serv_addr.sin_addr.s_addr, server->h_length);    //Copy contents of host server address resolved into serv_addr
+    serv_addr.sin_port = htons(portno);
+
+    if(connect(sockfd, (struct sockaddr*) &serv_addr, sizeof(serv_addr))<0) //Connecting to Server
+        error("Connection failed\n");
+
+
+    if (read_image_file("ddt-logo1.png", &buffer, &size_of_file)) {
+        error("\t Reading Image Failed");
+    }
+    //printf("\t Size of file : %d\n", size_of_file);
+    n = send_to_server(sockfd, &size_of_file, sizeof(int)); //Write to server
+    if (n < 0) {
+        error("\t Sending Size Failed");
+    }
+    printf("\t Sending File of size : %d\n",size_of_file);
+    n = send_to_server(sockfd, buffer, size_of_file);   //Write to server
+    if (n < size_of_file) {
+        error("\t Sending Image Failed");
+    }
+
+    len = recv(sockfd, reply, 1024, 0);
+    reply[len] = '\0';
+    printf("%s\n",reply);
+}
+
+int main(int argc, char *argv[]){
+    int i;
+    for (i = 0; i < 2; i++) {
+        client_func(argv);
+        sleep(2);
+    }
+    return 0;
+}