Vfrdtyky

I have this client and server program. I'm trying to add a history command where it displays the last 10 commands when you type "history" in the commandline, but I'm having issues with it where it won't display at all, but I'm not sure why it won't work. After I type "history" it won't display anything and I can't type any commands after which makes me have to re-launch the code be able to type unix commands in. This program works by sending unix commands such as "ls" or "date" and it will send the info from the server back to the client. It may be because my code is a little buggy, but it should still work. Any one can point me in the right direction?

Client:

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/socket.h>

#include <sys/types.h>

#include <netinet/in.h>

#include <arpa/inet.h>



#define BUFFSIZE 2048



char history[10][50];

int historyCounter = 0;



char *encryptedMessage(char command){

    int i = 0;



    while (command[i] != ''){

        command[i] += 5;

        i += 1;

    }



    return command;

}







int main(int argc, char *argv){

    /*Created variables for socket, server address, arguement size, and a buffer*/

    int clientSocket, ret, portnum;

    struct sockaddr_in serverAddr;

    int received = 0;

    unsigned int echolen;

    char buffer[BUFFSIZE];



    /*If there is less than 3 arguments, print out a statement explaining to execute program

    along witjh server ip and port*/

    if(argc < 3){

        fprintf(stderr,"usage %s <server-ip-addr> <server-port>n", argv[0]);

        exit(0);

    }

    /*Convert port number from the commandline using atoi*/

    portnum = atoi(argv[2]);



    /*Create socket, and check if there is an error in the connection*/

    clientSocket = socket(AF_INET, SOCK_STREAM, 0);

    if(clientSocket < 0){

        printf("Error in connection.n");

        exit(1);

    }

    printf("Client Socket is created.n");

    /*Memset server address*/

    memset(&serverAddr, '', sizeof(serverAddr));

    // memset(&buffer, '', sizeof(buffer));

    // serverAddr.sin_family = AF_INET;

    // serverAddr.sin_port = htons(PORT);

    // serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");



    // bzero((char *) &serverAddr, sizeof(serverAddr));



    /*Take ip address from commandline and set it into serverAddr*/

    serverAddr.sin_family = AF_INET;

    if(!inet_aton(argv[1], &serverAddr.sin_addr)){

        fprintf(stderr, "Error invalid server IP addressn");

        exit(1);

    }

    /*Take the port number and set it in the sin_port for connection*/

    serverAddr.sin_port = htons(portnum);

    /*Connect the client to the server, if less than 0, then there is an error in the connection*/

    ret = connect(clientSocket, (struct sockaddr*)&serverAddr, sizeof(serverAddr));

    if(ret < 0){

        printf("Error in connection.n");

        exit(1);

    }

    printf("Connected to server.n");

    /*Initialize argument buffer*/

    char s[100];

    /*In the while loop we take the arguments after we connect and put them in stdin, we insert  at the

    end of s array*/

    while(1){

        int _switch = 0;

        fgets(s, 100, stdin);

        historyCounter++;

        //s[strlen(s)-1]='';

        echolen = strlen(s);

        if(historyCounter < 10){

            for(int i = 0; i < historyCounter; i++){

                strcpy(history[i+1], history[i]);

            }

        }

        strcpy(history[0], s);



        /*  send() from client, if it doesn't equal echolen then show it failed */

        if(strcmp(s,"history") == 0){

            _switch = 1;

            int a = 0;

            int b = 0;



            for (int a = 0; a < historyCounter; a++){

                printf("%d", historyCounter);

                while(history[a][b] != ''){

                    printf("%c", history[a][b]);

                    b++;

                }

                b = 0;

                printf("n");

            }

            printf("n");



        }





        if(_switch == 0){

            if (send(clientSocket, s, echolen, 0) != echolen)

        {

            printf("Failed");

        }



        if(strcmp(s,"quit") == 0) //check if exit is typed

            exit(0);

        fprintf(stdout, "Message from server: ");

        //fprintf(stdin, "%sn", s);

        while (received < echolen)

        {

            ssize_t bytes = 0;

            /* recv() from server, the bytes we receive are from the clientSocket */

            if ((bytes = recv(clientSocket, buffer, echolen, 0)) < 1)

            {

                printf("Failed to get Information");

            }

            received += bytes;

            buffer[bytes] = '';

            /*WE receive the information and print in stdout what's in the buffer*/

            fprintf(stdout, buffer);

        }

        ssize_t bytes = 0;

        /*Place /0 at end of the buffer*/

        do {

            buffer[bytes] = '';

            printf("%sn", buffer);

        } while((bytes = recv(clientSocket, buffer, BUFFSIZE-1, 0))>=BUFFSIZE-1);

        buffer[bytes] = '';

        printf("%sn", buffer);

        printf("n");

        }



        /*Above is essentially printing out the information within the buffer from the recv()*/



    }

}

Server:

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/socket.h>

#include <sys/types.h>

#include <netinet/in.h>

#include <arpa/inet.h>



#define PORT 4444

#define BUFFSIZE 2048

#define MAX 2048

/*Full Credit implementing command argument functions: https://stackoverflow.com/questions/52796610/multiclient-and-server-commandline-argument-issues*/

/*setup() function take the input bugger and the arguments and tokenizes the arguments into the inputBuffer*/

void setup(char inputBuffer, char *args, int *background){

    const char s[4] = " tn";

    char *token;

    token = strtok(inputBuffer, s);

    int i = 0;

    while(token != NULL){

        args[i] = token;

        i++;

        token = strtok(NULL, s);

    }

    args[i] = NULL;

}

/*HandleClient() function take the socket, grabs the data from the client from the buffer*/

void HandleClient(int sock){

    char buffer[BUFFSIZE];

    int received = -1;

    char data[MAX];

    memset(data, 0, MAX);

    /*recv grabs info from the buffer*/

    while(1){

        data[0] = '';

        if((received = recv(sock, buffer, BUFFSIZE, 0)) < 0){

            printf("Error");

        }



        buffer[received] = '';



        strcat(data, buffer);

        if(strcmp(data, "exit") == 0){

            exit(0);

        }

        /*Put data into an arg array and pipe*/

        puts(data);

        char *args[100];

        setup(data, args, 0);

        int pipefd[2], length;



        if(pipe(pipefd)){

            printf("failed to create pipe");

        }

        /*Fork a child*/

        pid_t pid = fork();

        char path[MAX];



        if(pid==0)

        {

            close(pipefd[0]); // close the readonly side of the pipe

            //close(1); // close the original stdout

            dup2(pipefd[1],1); // duplicate pipfd[1] to stdout

            dup2(pipefd[1], fileno(stderr));

            //close(pipefd[0]); // close the readonly side of the pipe

            close(pipefd[1]); // close the original write side of the pipe

            printf("before execvp");

            execvp(args[0],args); // finally execute the command

            // exit(0);

        }

        else

            if(pid>0)

            {

                close(pipefd[1]);

                memset(path,'',MAX);

                while(length=read(pipefd[0],path,MAX-1)){

                    //printf("Data read so far %sn", path);

                    if(send(sock,path,strlen(path),0) != strlen(path) ){

                        printf("Failed");

                    }

                    fflush(NULL);

                    //printf("Data sent so far %sn", path);

                memset(path,0,MAX);

                }

                close(pipefd[0]);



                //exit(1); removed so server will not terminate

            }

            else

            {

                printf("Error !n");

                exit(0);//

            }



    }

}



char *decryptedMessage(char command){

    int i = 0;



    while (command[i] != ''){

        command[i] -= 5;

        i += 1;

    }



    return command;

}





int main(){

    /*Create all the sock, server address, and pid variables*/

    int sockfd, ret;

    struct sockaddr_in serverAddr;



    int newSocket;

    struct sockaddr_in newAddr;



    socklen_t addr_size;



    char buffer[1024];

    pid_t childpid;

    /*Create a socket*/

    sockfd = socket(AF_INET, SOCK_STREAM, 0);

    if(sockfd < 0){

        printf("Error in connection.n");

        exit(1);

    }

    printf("Server Socket is created.n");

    /*Memset the serverAddr, and put the ip and port number into the serverAddr structure*/

    memset(&serverAddr, '', sizeof(serverAddr));

    serverAddr.sin_family = AF_INET;

    serverAddr.sin_port = htons(PORT);

    serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");



    //printf("IP address is: %sn", inet_ntoa(client_addr.sin_addr));

    //printf("port is: %dn", (int) ntohs(client_addr.sin_port));



    /*Bind to the port*/

    ret = bind(sockfd, (struct sockaddr*)&serverAddr, sizeof(serverAddr));

    if(ret < 0){

        printf("Error in binding");

        exit(1);

    }

    printf("Bind to port %dn", 4444);



    if(listen(sockfd, 10) == 0){

        printf("Listening....n"); //Listening to accept connections

    }else{

        printf("Error in binding.n");

    }



    while(1){

        newSocket = accept(sockfd, (struct sockaddr*) &newAddr, &addr_size); //accept the socket and server address

        if(newSocket < 0){

            exit(1);

        }

        printf("Connection accepted from %s:%dn", inet_ntoa(newAddr.sin_addr), ntohs(newAddr.sin_port));



        //Take the buffer from the server and send it back to the client through the socket

        if((childpid = fork()) == 0){

            close(sockfd);



            while(1){

                recv(newSocket, buffer, 1024, 0); //recv() get the buffer and set the size 1024

                if(strcmp(buffer, "quit") == 0){

                    printf("Disconnected from %s:%dn", inet_ntoa(newAddr.sin_addr), ntohs(newAddr.sin_port));

                    break;

                }else{

                    printf("Client: %sn", buffer);

                    send(newSocket, buffer, strlen(buffer), 0); //sending info back to the client

                    bzero(buffer, sizeof(buffer));

                }

                HandleClient(newSocket);

            }

        }

    }





    close(newSocket);

    return 0;

}

fgets() reads until newline but also copies that newline at the end of input buffer. In strcmp() for history command it can fail. Pls check man page of fgets().