This repository has been archived on 2024-07-05. You can view files and clone it, but cannot push or open issues or pull requests.
Infinitum/httpd.c
2024-01-16 13:37:59 +01:00

231 lines
5.1 KiB
C

#include "httpd.h"
#include <arpa/inet.h>
#include <ctype.h>
#include <netdb.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <unistd.h>
#define MAX_CONNECTIONS 1000
#define BUF_SIZE 65535
#define QUEUE_SIZE 1000000
static int listenfd;
int *clients;
static void start_server(const char *);
static void respond(int);
static char *buf;
// Client request
char *method, // "GET" or "POST"
*uri, // "/index.html" things before '?'
*qs, // "a=1&b=2" things after '?'
*prot, // "HTTP/1.1"
*payload; // for POST
int payload_size;
void serve_forever(const char *PORT) {
struct sockaddr_in clientaddr;
socklen_t addrlen;
int slot = 0;
printf("Server started %shttp://127.0.0.1:%s%s\n", "\033[92m", PORT,
"\033[0m");
// create shared memory for client slot array
clients = mmap(NULL, sizeof(*clients) * MAX_CONNECTIONS,
PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0);
// Setting all elements to -1: signifies there is no client connected
int i;
for (i = 0; i < MAX_CONNECTIONS; i++)
clients[i] = -1;
start_server(PORT);
// Ignore SIGCHLD to avoid zombie threads
signal(SIGCHLD, SIG_IGN);
// ACCEPT connections
while (1) {
addrlen = sizeof(clientaddr);
clients[slot] = accept(listenfd, (struct sockaddr *)&clientaddr, &addrlen);
if (clients[slot] < 0) {
perror("accept() error");
exit(1);
} else {
if (fork() == 0) {
close(listenfd);
respond(slot);
close(clients[slot]);
clients[slot] = -1;
exit(0);
} else {
close(clients[slot]);
}
}
while (clients[slot] != -1)
slot = (slot + 1) % MAX_CONNECTIONS;
}
}
// start server
void start_server(const char *port) {
struct addrinfo hints, *res, *p;
// getaddrinfo for host
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;
if (getaddrinfo(NULL, port, &hints, &res) != 0) {
perror("getaddrinfo() error");
exit(1);
}
// socket and bind
for (p = res; p != NULL; p = p->ai_next) {
int option = 1;
listenfd = socket(p->ai_family, p->ai_socktype, 0);
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
if (listenfd == -1)
continue;
if (bind(listenfd, p->ai_addr, p->ai_addrlen) == 0)
break;
}
if (p == NULL) {
perror("socket() or bind()");
exit(1);
}
freeaddrinfo(res);
// listen for incoming connections
if (listen(listenfd, QUEUE_SIZE) != 0) {
perror("listen() error");
exit(1);
}
}
// get request header by name
char *request_header(const char *name) {
header_t *h = reqhdr;
while (h->name) {
if (strcmp(h->name, name) == 0)
return h->value;
h++;
}
return NULL;
}
// get all request headers
header_t *request_headers(void) { return reqhdr; }
// Handle escape characters (%xx)
static void uri_unescape(char *uri) {
char chr = 0;
char *src = uri;
char *dst = uri;
// Skip inital non encoded character
while (*src && !isspace((int)(*src)) && (*src != '%'))
src++;
// Replace encoded characters with corresponding code.
dst = src;
while (*src && !isspace((int)(*src))) {
if (*src == '+')
chr = ' ';
else if ((*src == '%') && src[1] && src[2]) {
src++;
chr = ((*src & 0x0F) + 9 * (*src > '9')) * 16;
src++;
chr += ((*src & 0x0F) + 9 * (*src > '9'));
} else
chr = *src;
*dst++ = chr;
src++;
}
*dst = '\0';
}
// client connection
void respond(int slot) {
int rcvd;
buf = malloc(BUF_SIZE);
rcvd = recv(clients[slot], buf, BUF_SIZE, 0);
if (rcvd < 0) // receive error
fprintf(stderr, ("recv() error\n"));
else if (rcvd == 0) // receive socket closed
fprintf(stderr, "Client disconnected upexpectedly.\n");
else // message received
{
buf[rcvd] = '\0';
method = strtok(buf, " \t\r\n");
uri = strtok(NULL, " \t");
prot = strtok(NULL, " \t\r\n");
uri_unescape(uri);
fprintf(stderr, "\x1b[32m + [%s] %s\x1b[0m\n", method, uri);
qs = strchr(uri, '?');
if (qs)
*qs++ = '\0'; // split URI
else
qs = uri - 1; // use an empty string
header_t *h = reqhdr;
char *t, *t2;
while (h < reqhdr + 16) {
char *key, *val;
key = strtok(NULL, "\r\n: \t");
if (!key)
break;
val = strtok(NULL, "\r\n");
while (*val && *val == ' ')
val++;
h->name = key;
h->value = val;
h++;
fprintf(stderr, "[H] %s: %s\n", key, val);
t = val + 1 + strlen(val);
if (t[1] == '\r' && t[2] == '\n')
break;
}
t = strtok(NULL, "\r\n");
t2 = request_header("Content-Length"); // and the related header if there is
payload = t;
payload_size = t2 ? atol(t2) : (rcvd - (t - buf));
// bind clientfd to stdout, making it easier to write
int clientfd = clients[slot];
dup2(clientfd, STDOUT_FILENO);
close(clientfd);
// call router
route();
// tidy up
fflush(stdout);
shutdown(STDOUT_FILENO, SHUT_WR);
close(STDOUT_FILENO);
}
free(buf);
}