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feuille/cgi/feuille.cgi.c

169 lines
4.8 KiB
C

/*
* misc/web/feuille.cgi.c
* Auxiliary CGI script that converts an HTTP request to a raw TCP
* one.
*
* Copyright (c) 2022
* Tom MTT. <tom@heimdall.pm>
*
* This file is licensed under the 3-Clause BSD License.
* You should have received a copy of the 3-Clause BSD License
* along with this program. If not, see
* <https://basedwa.re/tmtt/feuille/src/branch/main/LICENSE>.
*/
#include <arpa/inet.h> /* for inet_pton */
#include <errno.h> /* for ERANGE, errno */
#include <netinet/in.h> /* for htons, sockaddr_in, sockaddr_in6 */
#include <stdio.h> /* for printf, NULL, BUFSIZ */
#include <stdlib.h> /* for calloc, free, getenv, exit, strtoll */
#include <string.h> /* for strcmp */
#include <strings.h> /* for bzero */
#include <sys/socket.h> /* for connect, socket, AF_INET, AF_INET6, recv, send */
#include <unistd.h> /* for close, read, STDIN_FILENO */
/* Initialize client socket and connect to feuille */
int initialize_socket(char *address, unsigned short port)
{
int server;
/* initialize socket IPv4 and IPv6 addresses */
struct sockaddr_in server_address_v4;
bzero(&server_address_v4, sizeof(server_address_v4));
struct sockaddr_in6 server_address_v6;
bzero(&server_address_v6, sizeof(server_address_v6));
/* dirty hack to detect and convert IPv4 / IPv6 addresses */
if (inet_pton(AF_INET, address, &server_address_v4.sin_addr) == 1) {
/* set socket family and port */
server_address_v4.sin_family = AF_INET;
server_address_v4.sin_port = htons(port);
/* create socket */
if ((server = socket(AF_INET, SOCK_STREAM, 0)) < 0)
return -1;
/* connect to server */
if (connect(server, (struct sockaddr *)&server_address_v4, sizeof(server_address_v4)) < 0)
return -1;
} else if (inet_pton(AF_INET6, address, &server_address_v6.sin6_addr) == 1) {
/* set socket family and port */
server_address_v6.sin6_family = AF_INET6;
server_address_v6.sin6_port = htons(port);
/* create socket */
if ((server = socket(AF_INET6, SOCK_STREAM, 0)) < 0)
return -1;
/* connect to server */
if (connect(server, (struct sockaddr *)&server_address_v6, sizeof(server_address_v6)) < 0)
return -1;
} else
return -1;
return server;
}
/* CGI helper functions */
void cgi_init()
{
printf("Content-Type: text/plain\r\n");
}
void cgi_error(char *status)
{
printf("Status: %s\r\n", status);
printf("\r\n");
printf("%s\n", status);
}
void cgi_die(char *status)
{
cgi_error(status);
exit(1);
}
void cgi_ok(char *response)
{
printf("Status: 200 OK\r\n");
printf("\r\n");
printf("%s", response);
}
void cgi_redirect(char *url)
{
printf("Status: 301 Moved Permanently\r\n");
printf("Location: %s\r\n", url);
printf("\r\n");
}
/* main function */
int main(void)
{
cgi_init();
/* get method */
char *method;
if ((method = getenv("REQUEST_METHOD")) == NULL || strcmp(method, "POST") != 0)
cgi_die("405 Method Not Allowed");
/* get content length */
char *content_length;
if ((content_length = getenv("CONTENT_LENGTH")) == NULL)
cgi_die("400 Bad Request");
/* convert content length to a long long int */
long long length = strtoll(content_length, NULL, 10);
if (length <= 0 || errno == ERANGE)
cgi_die("400 Bad Request");
/* initialize socket */
int socket;
if ((socket = initialize_socket(ADDR, PORT)) == -1)
cgi_die("500 Internal Server Error");
/* read paste from stdin */
char *request;
if ((request = calloc(length + 1, sizeof(char))) == NULL)
cgi_die("500 Internal Server Error");
read(STDIN_FILENO, request, length);
request[length] = 0;
/* remove `paste=' from request */
char *paste = request;
char *offset;
if ((offset = strstr(request, "=")) != NULL) {
paste = offset + 1;
length -= offset + 1 - request;
}
/* send paste to feuille */
send(socket, paste, length + 1, 0);
shutdown(socket, SHUT_WR);
/* receive response from feuille */
char *response;
if ((response = calloc(BUFSIZ + 1, sizeof(char))) == NULL)
cgi_die("500 Internal Server Error");
if (recv(socket, response, BUFSIZ, 0) > 0) {
if (strstr(response, "http") != NULL)
cgi_redirect(response);
else
cgi_ok(response);
} else
cgi_error("500 Internal Server Error");
/* close socket, free variables and exit */
close(socket);
free(response);
free(request);
return 0;
}