Homework & Coursework Questions

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
void error(char *);

void main(int argc, char *argv[])
{
   int sockfd, servlen,n;
   struct sockaddr_un  serv_addr;
   char buffer[82];

   bzero((char *)&serv_addr,sizeof(serv_addr));
   serv_addr.sun_family = AF_UNIX;
   strcpy(serv_addr.sun_path, argv[1]);
   servlen = strlen(serv_addr.sun_path) + 
                 sizeof(serv_addr.sun_family);
   if ((sockfd = socket(AF_UNIX, SOCK_STREAM,0)) < 0)
       error("Creating socket");
   if (connect(sockfd, (struct sockaddr *) 
                         &serv_addr, servlen) < 0)
       error("Connecting");
   printf("Please enter your message: ");
   bzero(buffer,82);
   fgets(buffer,80,stdin);
   write(sockfd,buffer,strlen(buffer));
   n=read(sockfd,buffer,80);
   printf("The return message was\n");
   write(1,buffer,n);   
}

void error(char *msg)
{
    perror(msg);
    exit(0);
}

/* a server in the unix domain.  The pathname of 
   the socket address is passed as an argument */
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
void error(char *);
int main(int argc, char *argv[])
{
   int sockfd, newsockfd, servlen, clilen, n;
   struct sockaddr_un  cli_addr, serv_addr;
   char buf[80];

   if ((sockfd = socket(AF_UNIX,SOCK_STREAM,0)) < 0)
       error("creating socket");
   bzero((char *) &serv_addr, sizeof(serv_addr));
   serv_addr.sun_family = AF_UNIX;
   strcpy(serv_addr.sun_path, argv[1]);
   servlen=strlen(serv_addr.sun_path) + 
                     sizeof(serv_addr.sun_family);
   if(bind(sockfd,(struct sockaddr *)&serv_addr,servlen)<0)
       error("binding socket"); 

   listen(sockfd,5);
   clilen = sizeof(cli_addr);
   newsockfd = accept(
        sockfd,(struct sockaddr *)&cli_addr,&clilen);
   if (newsockfd < 0) 
        error("accepting");
   n=read(newsockfd,buf,80);
   printf("A connection has been established\n");
   write(1,buf,n);
   write(newsockfd,"I got your message\n",19);
}

void error(char *msg)
{
    perror(msg);
    exit(0);
}
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