Server reading a command line argument passed to the client - c

Question

I want to pass an argument to the client, send it to the server, then print it there, currently I am getting no output.
Current codes:
Client:
#include <stdio.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include<errno.h>
#define PORT 8080
int main(int argc, char const *argv[])
{
int sock = 0, valread;
struct sockaddr_in serv_addr;
char buffer[1024] = {0};
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
printf("\n Socket creation error \n");
return -1;
}
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(PORT);
if(inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr)<=0)
{
printf("Invalid address \n");
return -1;
}
if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
{
printf("Connection Failed \n");
return -1;
}
int i;
if(argc>=2){
for(i=0; i<argc; i++) {
if(write( sock, argv[i], 1 + strlen( argv[i] ))<0)
{
printf("Error in write() ! %s\n", strerror(errno));
return -1;
}
}
}
return 0;
}
Server:
#include <unistd.h>
#include <stdio.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <string.h>
#include<errno.h>
#define PORT 8080
int main(int argc, char const *argv[])
{
int server_fd, new_socket, valread;
struct sockaddr_in address;
int opt = 1;
int addrlen = sizeof(address);
char buffer[1024] = {0};
char *hello = "Hello from server";
if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0)
{
perror("socket failed");
exit(EXIT_FAILURE);
}
if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR , &opt, sizeof(opt)))
{
perror("setsockopt");
exit(EXIT_FAILURE);
}
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons( PORT );
if (bind(server_fd, (struct sockaddr *)&address,
sizeof(address))<0)
{
perror("bind failed");
exit(EXIT_FAILURE);
}
if (listen(server_fd, 3) < 0)
{
perror("listen");
exit(EXIT_FAILURE);
}
if ((new_socket = accept(server_fd, (struct sockaddr *)&address,
(socklen_t*)&addrlen))<0)
{
perror("accept");
exit(EXIT_FAILURE);
}
valread = read(new_socket , buffer, 1024);
puts("The client sent the value: ");
int* valuerec=(int *)buffer;
int val2=*valuerec;
return 0;
}
Currently I am getting no number as an output, how can I do fix this? Ultimately my goal would be to send and receive multiple arguments but for now I am only sending one.

Answer 1

the following proposed code:
cleanly compiles
performs the desired server functionality
properly checks for errors
properly handles errors
uses an appropriate signature for function: main()
does not include header files those contents are not used
uses meaningful names rather than 'magic' numbers
uses appropriate horizontal spacing for readability
properly NUL terminates the input buffer
note the function: atoi() does not indicate when an error occurs, so suggest using strtol() instead
properly cleared the struct address before setting some of the fields
and now the proposed code:
#include <unistd.h>
#include <stdio.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#define PORT 8080
#define MAX_BUFFER_LEN 1025
int main( void )
{
int server_fd, new_socket;
struct sockaddr_in address;
if ( ( server_fd = socket( AF_INET, SOCK_STREAM, 0 ) ) < 0 )
{
perror( "socket failed" );
exit( EXIT_FAILURE );
}
int opt = 1;
if ( setsockopt( server_fd, SOL_SOCKET, SO_REUSEADDR , &opt, sizeof(opt) ) )
{
perror("setsockopt failed" );
exit( EXIT_FAILURE );
}
memset( &address, 0, sizeof( address ) );
address.sin_family = AF_INET;
address.sin_addr.s_addr = htonl( INADDR_ANY );
address.sin_port = htons( PORT );
socklen_t addrlen = sizeof( address );
if ( bind( server_fd, (struct sockaddr *)&address, addrlen ) < 0 )
{
perror( "bind failed" );
exit( EXIT_FAILURE );
}
if ( listen( server_fd, 3 ) < 0 )
{
perror( "listen failed" );
exit( EXIT_FAILURE );
}
if (( new_socket = accept(server_fd, (struct sockaddr *)&address,
(socklen_t*)&addrlen ) ) < 0 )
{
perror( "accept failed" );
exit( EXIT_FAILURE );
}
ssize_t valread;
char buffer[ MAX_BUFFER_LEN ] = { 0 };
if( ( valread = read( new_socket, buffer, MAX_BUFFER_LEN -1 ) ) > 0 )
{ // then read successful
buffer[ valread ] = '\0';
int value = atoi( buffer );
printf( "The client sent the string: %s, which began with integer value: %d\n", buffer, value );
}
else if( ! valread )
{
puts( "client hungup" );
}
else
{
perror( "read failed" );
}
return 0;
}