c code for a server that creates a log file

[Nosia]

hello everyone
i am trying to write a c code for a server that recieve msgs from a client and put that msg in a log file dedicated for that client along with the msg reception time and client IP addrs.......
The log file must be created if it doesn't already exist.....
here is a code that i wnat to customize and it already opens a communication channel between server and client......
here is my code:

#include "stdio.h"
#include "stdlib.h"
#include "sys/socket.h"
#include "sys/types.h"
#include "netinet/in.h"
#include "error.h"
#include "strings.h"
#include "unistd.h"
#include "arpa/inet.h"

#define ERROR    -1
#define MAX_CLIENTS    4
#define MAX_DATA    1024


main(int argc, char **argv)
{
    struct sockaddr_in server;
    struct sockaddr_in client;
    int sock;
    int new,i;
    int sockaddr_len = sizeof(struct sockaddr_in);
    int data_len;
    char data[MAX_DATA];
    char temp[MAX_DATA];
    
    
    if((sock = socket(AF_INET, SOCK_STREAM, 0)) == ERROR)
    {
        perror("server socket: ");
        exit(-1);
    }
        
    server.sin_family = AF_INET;
    server.sin_port = htons(atoi(argv[1]));
    server.sin_addr.s_addr = INADDR_ANY;
    bzero(&server.sin_zero, 8);
            
    if((bind(sock, (struct sockaddr *)&server, sockaddr_len)) == ERROR)
    {
        perror("bind : ");
        exit(-1);
    }
    
    if((listen(sock, MAX_CLIENTS)) == ERROR)
    {
        perror("listen");
        exit(-1);
    }
    printf("\nThe TCPServer Waiting for client on port %d\n",ntohs(server.sin_port));
        fflush(stdout);
    
    while(1) // Better signal handling required
    {
        if((new = accept(sock, (struct sockaddr *)&client, &sockaddr_len)) == ERROR)
        {
            perror("accept");
            exit(-1);
        }
        
        printf("New Client connected from port no %d and IP %s\n", ntohs(client.sin_port), inet_ntoa(client.sin_addr));

        data_len = 1;
    
                
        while(data_len)
        {
            data_len = recv(new, data, MAX_DATA, 0);
            printf("\nRecieved mesg from client: %s", data);
            
            for( i = 0; data[ i ]; i++)
            {
                if(data[i]=='a' || data[i]=='e' || data[i]=='i' ||data[i]=='o' || data[i]=='u' )
                    data[ i ] = toupper( data[ i ] );
                else
                data[ i ] = data[ i ] ;
                
            }    
            
            if(data_len)
            {
                
                send(new, data, data_len, 0);
                data[data_len] = '\0';
                printf("\nSent mesg to client: %s", data);
            }
            
        }

        printf("Client disconnected\n");
        
        close(new);
        
    }

    close(sock);

        
}

[johny10151981]

What is the problem?

[Nosia]

the problem is that this code only recieve msg from client and set vowel letters to upper case.....i want it to recieve msg and put it in a log file along with the client IP address and time of msg reception...
tanks for care....

[Banfa]

Well you know how to use printf it is a small step from printf to fprintf, fopen, fclose (and other file handling functions).

Are you really saying you know how to open a socket but not how to open a file?

[Nosia]

thanks Banfa i know how to open a socket but i tried hard to open a file using fopen and fclose and it compiled successfully but when executed it gives an error of "core dumped" type.......
that is why am asking for help.......


thanks...

[Nosia]

#include "stdio.h"
#include "stdlib.h"
#include "sys/socket.h"
#include "sys/types.h"
#include "netinet/in.h"
#include "error.h"
#include "strings.h"
#include "unistd.h"
#include "arpa/inet.h"
#include <fcntl.h>
#include <unistd.h>





#define ERROR -1
#define MAX_CLIENTS 4
#define MAX_DATA 1024
#define true 1

main(int argc, char **argv)
{
struct sockaddr_in server;
struct sockaddr_in client;
int sock;
int new,i,fd;
int sockaddr_len = sizeof(struct sockaddr_in);
int data_len;
char data[MAX_DATA];
char temp[MAX_DATA];


if((sock = socket(AF_INET, SOCK_STREAM, 0)) == ERROR)
{
perror("server socket: ");
exit(-1);
}

server.sin_fami ly = AF_INET;
server.sin_port = htons(atoi(argv[1]));
server.sin_addr .s_addr = INADDR_ANY;
bzero(&server.s in_zero, 8);

if((bind(sock, (struct sockaddr *)&server, sockaddr_len)) == ERROR)
{
perror("bind : ");
exit(-1);
}

if((listen(sock , MAX_CLIENTS)) == ERROR)
{
perror("listen" );
exit(-1);
}
printf("\nThe TCPServer Waiting for client on port %d\n",ntohs(ser ver.sin_port));
fflush(stdout);


fd=open("test.l og",O_WRONLY | O_APPEND | O_CREAT,0644);
if (!fd)
{
perror("file not open \n");
return -1;
}
while(1) // Better signal handling required
{
if((new = accept(sock, (struct sockaddr *)&client, &sockaddr_le n)) == ERROR)
{
perror("accept" );
exit(-1);
}

printf("New Client connected from port no %d and IP %s\n", ntohs(client.si n_port), inet_ntoa(clien t.sin_addr));

data_len = 1;


while(data_len)
{
data_len = recv(new, data, MAX_DATA, 0);
printf("\nRecie ved mesg from client: %s", data);

for( i = 0; data[ i ]; i++)
{

write(fd,data,M AX_DATA);
bzero(&data,MAX _DATA);

}

}

printf("Client disconnected\n" );

close(new);

}
close(fd);
close(sock);


}



here is the customized code but when executed it gives an error of type "core dumped"



help please..

[donbock]

data_len = recv(new, data, MAX_DATA, 0);
printf("\nRecieved mesg from client: %s", data);

Are you confident that the received data is a null-terminated string?

for( i = 0; data[ i ]; i++)
{
   write(fd,data,MAX_DATA);
   bzero(&data,MAX_DATA);
}

This code iterates for each non-null character in data[], but each time it writes the entire array to the log file (regardless of how many bytes were actually received) and fills the data array with zeroes.

[Nosia]

yes that is right and i solved the problem by taking out the for loop and use sprintf function......
thank you donbock.....