This Multi-threaded web server takes advantage of the posix thread library to enable it it serve multiple files at the same time. Compile using gcc and run on a linux server.
// Multi-Threaded web server using posix pthreads
// BK Turley 2011
//this simple web server is capible of serving simple html, jpg, gif & text files
//----- Include files ---------------------------------------------------------
#include <stdio.h> // for printf()
#include <stdlib.h> // for exit()
#include <string.h> // for strcpy(),strerror() and strlen()
#include <fcntl.h> // for file i/o constants
#include <sys/stat.h> // for file i/o constants
#include <errno.h>
/* FOR BSD UNIX/LINUX ---------------------------------------------------- */
#include <sys/types.h> //
#include <netinet/in.h> //
#include <sys/socket.h> // for socket system calls
#include <arpa/inet.h> // for socket system calls (bind)
#include <sched.h>
#include <pthread.h> /* P-thread implementation */
#include <signal.h> /* for signal */
#include <semaphore.h> /* for p-thread semaphores */
/* ------------------------------------------------------------------------ */
//----- HTTP response messages ----------------------------------------------
#define OK_IMAGE "HTTP/1.0 200 OKnContent-Type:image/gifnn"
#define OK_TEXT "HTTP/1.0 200 OKnContent-Type:text/htmlnn"
#define NOTOK_404 "HTTP/1.0 404 Not FoundnContent-Type:text/htmlnn"
#define MESS_404 "<html><body><h1>FILE NOT FOUND</h1></body></html>"
//----- Defines -------------------------------------------------------------
#define BUF_SIZE 1024 // buffer size in bytes
#define PORT_NUM 6110 // Port number for a Web server (TCP 5080)
#define PEND_CONNECTIONS 100 // pending connections to hold
#define TRUE 1
#define FALSE 0
#define NTHREADS 5 /* Number of child threads */
#define NUM_LOOPS 10 /* Number of local loops */
#define SCHED_INTVL 5 /* thread scheduling interval */
#define HIGHPRIORITY 10
/* global variables ---------------------------------------------------- */
sem_t thread_sem[NTHREADS];
int next_thread;
int can_run;
int i_stopped[NTHREADS];
unsigned int client_s; // Client socket descriptor
/* Child thread implementation ----------------------------------------- */
void *my_thread(void * arg)
{
unsigned int myClient_s; //copy socket
/* other local variables ------------------------------------------------ */
char in_buf[BUF_SIZE]; // Input buffer for GET resquest
char out_buf[BUF_SIZE]; // Output buffer for HTML response
char *file_name; // File name
unsigned int fh; // File handle (file descriptor)
unsigned int buf_len; // Buffer length for file reads
unsigned int retcode; // Return code
myClient_s = *(unsigned int *)arg; // copy the socket
/* receive the first HTTP request (HTTP GET) ------- */
retcode = recv(client_s, in_buf, BUF_SIZE, 0);
/* if receive error --- */
if (retcode < 0)
{ printf("recv error detected ...n"); }
/* if HTTP command successfully received --- */
else
{
/* Parse out the filename from the GET request --- */
strtok(in_buf, " ");
file_name = strtok(NULL, " ");
//test for high priority file
if(0 == strcmp(&file_name[1],"test_00.jpg")){
int diditwork = pthread_setschedprio(pthread_self(), HIGHPRIORITY);
if(!diditwork)
printf("priority wasn't increased correctly ...n");
else{
printf("High priority thread created ...n");
}
}
/* Open the requested file (start at 2nd char to get rid of leading "") */
fh = open(&file_name[1], O_RDONLY, S_IREAD | S_IWRITE);
/* Generate and send the response (404 if could not open the file) */
if (fh == -1)
{
printf("File %s not found - sending an HTTP 404 n", &file_name[1]);
strcpy(out_buf, NOTOK_404);
send(client_s, out_buf, strlen(out_buf), 0);
strcpy(out_buf, MESS_404);
send(client_s, out_buf, strlen(out_buf), 0);
}
else
{
printf("File %s is being sent n", &file_name[1]);
if ((strstr(file_name, ".jpg") != NULL)||(strstr(file_name, ".gif") != NULL))
{ strcpy(out_buf, OK_IMAGE); }
else
{ strcpy(out_buf, OK_TEXT); }
send(client_s, out_buf, strlen(out_buf), 0);
buf_len = 1;
while (buf_len > 0)
{
buf_len = read(fh, out_buf, BUF_SIZE);
if (buf_len > 0)
{
send(client_s, out_buf, buf_len, 0);
//printf("%d bytes transferred ..n", buf_len);
}
}
close(fh); // close the file
close(client_s); // close the client connection
pthread_exit(NULL);
}
}
}
//===== Main program ========================================================
int main(void)
{
/* local variables for socket connection -------------------------------- */
unsigned int server_s; // Server socket descriptor
struct sockaddr_in server_addr; // Server Internet address
//unsigned int client_s; // Client socket descriptor
struct sockaddr_in client_addr; // Client Internet address
struct in_addr client_ip_addr; // Client IP address
int addr_len; // Internet address length
unsigned int ids; // holds thread args
pthread_attr_t attr; // pthread attributes
pthread_t threads; // Thread ID (used by OS)
/* create a new socket -------------------------------------------------- */
server_s = socket(AF_INET, SOCK_STREAM, 0);
/* fill-in address information, and then bind it ------------------------ */
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT_NUM);
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
bind(server_s, (struct sockaddr *)&server_addr, sizeof(server_addr));
/* Listen for connections and then accept ------------------------------- */
listen(server_s, PEND_CONNECTIONS);
/* the web server main loop ============================================= */
pthread_attr_init(&attr);
while(TRUE)
{
printf("my server is ready ...n");
/* wait for the next client to arrive -------------- */
addr_len = sizeof(client_addr);
client_s = accept(server_s, (struct sockaddr *)&client_addr, &addr_len);
printf("a new client arrives ...n");
if (client_s == FALSE)
{
printf("ERROR - Unable to create socket n");
exit(FALSE);
}
else
{
/* Create a child thread --------------------------------------- */
ids = client_s;
pthread_create ( /* Create a child thread */
&threads, /* Thread ID (system assigned) */
&attr, /* Default thread attributes */
my_thread, /* Thread routine */
ids); /* Arguments to be passed */
}
}
/* To make sure this "main" returns an integer --- */
close (server_s); // close the primary socket
return (TRUE); // return code from "main"
}