#ifdef PLAN9#include <u.h>#include <libc.h>#include <ctype.h>#else#include <stdio.h>#include <string.h>#include <stdlib.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>#include "linux.h"#endif #include "dat.h"#include "fns.h" intparse(char *buf, Request *req){	static int first_header = 1; // interesting	char      *endptr;	int        len; 	if (first_header) {		if (!strncmp(buf, "GET ", 4)) {			req->method = GET;			buf += 4;		} else {			req->method = UNSUPPORTED;			req->status = 501;		} 		while (*buf && isspace(*buf))			buf++; 		endptr = strchr(buf, ' ');		if (endptr == 0)			len = strlen(buf);		else			len = endptr - buf;		if (!len) {			req->status = 400;			return -1;		} 		req->resource = calloc(len+1, sizeof(char));		strncpy(req->resource, buf, len); 		if (strstr(buf, "HTTP/"))			req->type = FULL;		else			req->type = SIMPLE; 		first_header = 0;		return 0;	}	return 0;} voidreqinit(Request *req){	req->status = 200;} voidinitresourcepath(){	resourcepath = calloc(MaxLineLen, sizeof(char));} intopenresource(Request *req){	cleanURL(req->resource);	strcat(resourcepath, root);	strcat(resourcepath, req->resource);	return open(resourcepath, OREAD);} voidoutputheaders(int fd, Request *req){	char buf[100];	sprint(buf, "HTTP/1.0 %d OK\r\r", req->status);	writeline(fd, buf, strlen(buf)); 	writeline(fd, "Server: httpbench\r\n", strlen("Server: httpbench\r\n"));	writeline(fd, "Content-Type: text/html\r\n", 25);	writeline(fd, "\r\n", 2);} intsendresource(int conn, int resource){    char c[1024];    int  i;     while ( (i = read(resource, c, 1024)) ) {	if ( i < 0 )	    exits("Error reading from file.");	if ( write(conn, c, i) < 1 )	    exits("Error sending file.");    }     return 0;} intsenderror(int conn, Request* reqinfo){        char buffer[100];     sprint(buffer, "<HTML>\n<HEAD>\n<TITLE>Server Error %d</TITLE>\n"	            "</HEAD>\n\n", reqinfo->status);    writeline(conn, buffer, strlen(buffer));     sprint(buffer, "<BODY>\n<H1>Server Error %d</H1>\n", reqinfo->status);    writeline(conn, buffer, strlen(buffer));     sprint(buffer, "<P>The request could not be completed.</P>\n"	            "</BODY>\n</HTML>\n");    writeline(conn, buffer, strlen(buffer));     return 0; } voidhandler(int fd){	char buffer[MaxLineLen] = {0};	Request req;	int rfd; // resource fd 	reqinit(&req); 	alarm(TIMEOUT);	do {		readline(fd, buffer, MaxLineLen - 1);		trim(buffer);		if (buffer[0] == '\0')			break;		if (parse(buffer, &req))			break;	} while (req.type != SIMPLE);	alarm(0);	rfd = openresource(&req); // make sure the resource exists	if (rfd < 0)		req.status = 404;	if (req.type == FULL)		outputheaders(fd, &req); 	if (req.status == 200) {		if (sendresource(fd, rfd))			exits("something bad happened while sending the resource\n");	} else {		senderror(fd, &req);	}	close(fd);	exits(0);}