SeaWeb/cmd/server.c

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <openssl/ssl.h>
#include <errno.h>
#include <wait.h>

// Local Includes
#include "httpStruct.h"
#include "socketHelp.h"
#include "returnRequest.h"
#include "server.h"
#include "utils.h"
#include "requestHandlers.h"

#define WEB_ROOT "/var/www/html/"
//#define WEB_ROOT "content/"
#define BUFF_READ 1024

static int verbose_flag = 0;
bool enableHTTPS = 0;
char *WEB_ROOT_DIR = NULL;

static int timeout = 0;

/*
 * Used to print debug messages to the screen
 * when the --verbose flag is passed
 */
int printDebug(char message[]) {
	if (verbose_flag == 1) {
		printf("[Debug] %s\n", message);
	}
	return 0;
}

/*
 * This function handles incoming requests and stores
 * the parsed data into the HTTPRequest struct passed
 * into the function. If any errors are encountered
 * during this process a negative number will be returned
 */
int parseHTTPRequest(unsigned char *buffer, struct HTTPRequest *r) {
	char temp[1]; // Used to check newlines
	char *token = calloc(8, sizeof(char));
	int line = 0;
	int contentCheck = 0;
	unsigned char *checkLine = calloc(1000, sizeof(unsigned char));
	size_t checkLineLen = 0;
	unsigned char *logLine = malloc(sizeof(unsigned char));
	char * varCheck;

	// Creating empty requestBody
	// Setting values to 0 helps if variable is not
	// set and determining that later on in handling
	r->requestBody = malloc(sizeof(char));
	r->requestBodyLen = 0;
	r->requestVars = malloc(sizeof(char));
	memset(r->requestBody, 0, sizeof(char));
	memset(r->requestVars, 0, sizeof(char));

	for (int i = 0; i <= strlen((char *)buffer); i++) {
		temp[0] = buffer[i];
		// Checking for newline character OR end of string
		if (((!strcmp(temp, "\n")) && (i != 0)) || (i == strlen((char *)buffer))) {
			// Config Check
			if (line == 0) { // Grabbing first line for type parsing
				logLine = calloc(strlen((char *)checkLine), sizeof(char));
				strcpy((char *)logLine, (char *)checkLine);
				token = strtok((char *)checkLine, " ");
				// HTTP Request Type
				if ((!strcmp(token, "GET")) || (!strcmp(token, "POST")) ||
						(!strcmp(token, "PUT")) || (!strcmp(token, "DELETE")) ||
						(!strcmp(token, "CONNECT")) || (!strcmp(token, "HEAD"))) {
					// Grabbing HTTP Request Type
					r->requestType = malloc(strlen(token));
					strcpy(r->requestType, token);
					// Grabbing HTTP Request Dir
					token = strtok(NULL, " ");
					varCheck = strchr(token, '?');
					if (varCheck != NULL) {
						*varCheck = ' ';
					}
					sscanf(token, "%ms %ms", &r->requestDir, &r->requestVars);
					// Grabbing HTTP Request Version
					token = strtok(NULL, "");
					token[strlen(token) - 1] = '\0'; // Fixing version end char
					r->requestVersion = malloc(strlen(token));
					strcpy(r->requestVersion, token);
				} else { // First line contains unsupported request
					free(logLine);
					free(checkLine);
					return 2;
				}
				// Log Request
				PrintLog(logLine);
			} else { // Gather information on >first line
				if (contentCheck) { // Once content check is set to one everything after is part of the body
					printf("Check Line: %s\n", checkLine);
					r->requestBody = realloc(r->requestBody,
							(checkLineLen + r->requestBodyLen + 2));
					strcat((char *)r->requestBody, (char *)checkLine);
					// Adding newline to requestBody
					strcat((char *)r->requestBody, "\n");
					r->requestBodyLen += checkLineLen + 2;
					printf("Size: %zu\nCheck Size: %zu\n", r->requestBodyLen, checkLineLen);
					printf("Req:\n%s\n", r->requestBody);
				} else { // Information parsing !content
					if (strlen((char *)checkLine) == 1) { // Looking for blank empty line to end header info
						contentCheck = 1;
					}
					token = strtok((char *)checkLine, ":");
					// Host Check
					if (!strcmp(token, "Host")) {
						token = strtok(NULL, "");
						r->requestHost = malloc(strlen(token));
						strcpy(r->requestHost, token);
					} else if (!strcmp(token, "Content-Type")) {
						token = strtok(NULL, ":");
						r->requestConType = malloc(strlen(token));
						strcpy(r->requestConType, token);
					} else if (!strcmp(token, "Content-Length")) {
						token = strtok(NULL, ":");
						if (token == NULL) {
							printDebug("Content-length parsing error");
							return -1;
						}
						r->requestConLen = malloc(strlen(token));
						strcpy(r->requestConLen, token);
					}
				}
			}
			if (strlen((char *)checkLine) > 0) {
				// Clear checkLine
				memset(checkLine,0,strlen((char *)checkLine));
				checkLineLen = 0;
			}
			line++;
		} else {
			// Appending char to checkLine
			strcat((char *)checkLine, temp);
			checkLineLen++;
		}
	}

	// Return error if request type is not set
	if (strlen(r->requestType) == 0) {
		free(logLine);
		free(checkLine);
		return -1;
	}

	free(logLine);
	free(checkLine);
	return 0;
}

/*
 * This function is the entry point for all new requests; this
 * function will always return 0 regardless of outcome
 */
int handleRequest(unsigned char buffer[], int socket, SSL *ssl) {
	struct HTTPRequest r; // Holds relevant HTTP request information
	r.requestConLen = malloc(sizeof(char));
	r.requestConType = NULL;
	int checkerr = 0;

	// Grabbing relevant information out of request
	checkerr = parseHTTPRequest(buffer, &r);
	if (checkerr != 0) { // Checking for HTTP parsing error
		printDebug("Error parsing...");
		if (checkerr == -1) {
			printDebug("Error reading request, returning empty 500");
			return500Request(socket, ssl);
		} else {
			printDebug("Error parsing, returning 501");
			return501Request(socket, ssl);
		}
	} else {
		checkerr = checkHTTPVersion(r.requestVersion);
		if (checkerr != 0) {
			return505Request(socket, ssl);
		} else {
			if (!strcmp(r.requestType, "GET")) {
				handleGetRequest(socket, &r, ssl);
			} else if (!strcmp(r.requestType, "POST")) {
				handlePOSTRequest(socket, &r, ssl);
			} else if (!strcmp(r.requestType, "PUT")) {
				handlePUTRequest(socket, &r, ssl);
			} else if (!strcmp(r.requestType, "DELETE")) {
				handleDELETERequest(socket, &r, ssl);
			} else if (!strcmp(r.requestType, "CONNECT")) {
				return200Request(socket, NULL, ssl);
			} else if (!strcmp(r.requestType, "HEAD")) {
				return200Request(socket, NULL, ssl);
			} else {
				return500Request(socket, ssl);
			}
		}
	}

	free(r.requestConLen);
	return 0;
}

/*
 * This function is used as a signal to kill child processes that
 * are triggered by the corresponding alarm
 */
void timeoutChild(int sig) {
	timeout = 1;
}

int main(int argc, char **argv) {
	struct sockaddr_in address;
	int server_fd, new_socket;
	int port = 0; // Define what port server listens on
	int checkerr = 0; // Used for error checking
	int addrlen = sizeof(address);

	char *certFile = malloc(sizeof(char));
	char *privKeyFile = malloc(sizeof(char));
	certFile[0] = '\0';
	privKeyFile[0] = '\0';

	uint32_t listenAddrNum = -1;
	char *listenAddr = malloc(sizeof(char));
	listenAddr[0] = '\0';

	SSL_CTX *ctx = NULL;

	size_t bufSize = BUFF_READ;
	unsigned char *buffer = calloc(bufSize, sizeof(unsigned char));

	// Copy WEB_ROOT into extern value
	WEB_ROOT_DIR = malloc(strlen(WEB_ROOT));
	strcpy(WEB_ROOT_DIR, WEB_ROOT);

	// Setting up options
	static const struct option long_options[] = {
		{"help", no_argument, NULL, 'h'},
		{"port", required_argument, NULL, 'p'},
		{"listen", required_argument, NULL, 'l'},
		{"cert", required_argument, NULL, 'c'},
		{"privkey", required_argument, NULL, 'k'},
		{"verbose", no_argument, &verbose_flag, 1},
		{0, 0, 0, 0}
	};

	// Define help message
	const char* usage =
		"Usage: seaweb [options]\n\n"
		"  -h --help\t\t\tShows this message\n"
		"  -p --port\t\t\tStarts webserver on passed port\n"
		"  -l --listen\t\t\tDefines what addr to listen on (default 0.0.0.0)\n"
		"  -c --cert\t\t\tPath to certificate\n"
		"  -k --privkey\t\t\tPath to private key\n"
		"\n"
		"\n"
		"  --verbose\t\t\tPrints debug messages\n"
		"\n";

	// Parsing options
	int c;
	while (1) {
		int option_index = 0;
		c = getopt_long(argc, argv, "hp:l:c:k:", long_options, &option_index);
		if(c == -1) { // Break if no more options are present to parse
			break;
		}
		switch(c) {
			case 'h':
				printf("%s", usage);
				exit(EXIT_SUCCESS);
			case 'p':
				sscanf(optarg, "%d", &port);
				break;
			case 'l':
				listenAddr = calloc(strlen(optarg), sizeof(char));
				strcpy(listenAddr, optarg);
				listenAddrNum = addr2sin_addr(listenAddr);
				if (listenAddrNum == -1) {
					exit(EXIT_FAILURE);
				}
				break;
			case 'c':
				certFile = calloc(strlen(optarg), sizeof(char));
				strcpy(certFile, optarg);
				printf("Cert: %s\n", certFile);
				break;
			case 'k':
				privKeyFile = calloc(strlen(optarg), sizeof(char));
				strcpy(privKeyFile, optarg);
				printf("Priv: %s\n", privKeyFile);
				break;
		}
	}

	// Argument checks
	if (port == 0) { // Setting default port if none is passed
		port = 8080;
	}
	if (!((strlen(certFile) > 0) == (strlen(privKeyFile) > 0))) { // XNOR of string lengths
		// Checking what flag was not passed
		if (strlen(certFile)) { // Privkey not passed
			printf("If certificate file is specified, a private key files needs to be specified\n");
		} else if (strlen(privKeyFile)) { // Cert not passed
			printf("If privkey file is specified, a certificate files needs to be specified\n");
		}
		printf("Exiting...\n");
		exit(EXIT_FAILURE);
	} else if ( (strlen(certFile) > 0) && (strlen(privKeyFile) > 0) ) { // Enabling HTTPS
			enableHTTPS = 1;
	}

	if ( enableHTTPS == 1 ) { // Open secure socket
		printf("Opening secure socket on port: %d\n", port);
		checkerr = createSecureSocket(port, &server_fd, &address, &addrlen, listenAddrNum,
				&ctx, certFile, privKeyFile);
		if ( ctx == NULL ) {
			printf("Error creating ctx\n");
		}
	} else { // Open socket
		printf("Opening socket on port: %d\n", port);
		checkerr = createSocket(port, &server_fd, &address, &addrlen, listenAddrNum);
	}

	if (checkerr != 0) {
		perror("Error creating socket");
		exit(EXIT_FAILURE);
	}

	// Handle incoming requests
	while(1) {
		if ((new_socket = accept(server_fd, (struct sockaddr *)&address,
					(socklen_t *)&addrlen))<0) {
			perror("Accept connection error");
			exit(EXIT_FAILURE);
		}
		// Forking process
		pid_t pid;
		pid = fork();

		if (pid == 0) { // Child process handles sessions
			pid_t pid2;
			pid2 = fork();

			if (pid2 == 0) { // Child child process reads requests and handles return
				bufSize = BUFF_READ;
				if ( enableHTTPS ) {
					size_t buffCont = 1;
					SSL *ssl;
					ssl = SSL_new(ctx);
					SSL_set_fd(ssl, new_socket);
					SSL_accept(ssl);
					do {
					buffCont = SSL_read(ssl, buffer, BUFF_READ);
					if (strlen((char *)buffer) == bufSize) {
						bufSize *= 2;
						buffer = realloc(buffer, bufSize);
					}
					} while(buffCont == 0);
					if (strlen((char *)buffer) != 0) {
						handleRequest(buffer, new_socket, ssl);
						free(buffer);
					} else {
						printDebug("Error reading from socket");
					}
				} else {
					size_t buffCont = 1;
					do {
					buffCont = read(new_socket, buffer, BUFF_READ);
					if (strlen((char *)buffer) == bufSize) {
						bufSize *= 2;
						buffer = realloc(buffer, bufSize);
					}
					} while(buffCont == 0);

					handleRequest(buffer, new_socket, NULL);
					free(buffer);
				}
				exit(EXIT_SUCCESS);
			} else if (pid2 < 0) {
				printDebug("Error forking supervisor...");
			} else { // Parent process waits to see if child timeout is triggered
				int status;
				signal(SIGALRM, timeoutChild);
				alarm(2);
				pause();
				if (timeout) {
					status = waitpid(pid, NULL, WNOHANG);
					if (status == 0) { // If status is not 0 kill child process
						printDebug("Killing child");
						kill(pid2, 9);
						wait(NULL);
					}
				}
				exit(EXIT_SUCCESS);
			}
			close(new_socket);
		} else if (pid < 0) {
			printDebug("Error forking...");
		} else { // Ignore exit status of spawned child (proc is not a zombie)
			signal(SIGCHLD, SIG_IGN);
			close(new_socket);
			continue;
		}
	}
	free(privKeyFile);
	free(certFile);
	free(listenAddr);
	free(buffer);
	free(WEB_ROOT_DIR);
	close(server_fd);
	exit(EXIT_SUCCESS);
}