/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ /* * for GET or POST to /magic/save/foo. * add incoming data to foo.data. * send foo.html as reply. * * supports foo.data with "exclusive use" mode to prevent interleaved saves. * thus http://cm.bell-labs.com/magic/save/t?args should access: * -lrw-rw--w- M 21470 ehg web 1533 May 21 18:19 /usr/web/save/t.data * --rw-rw-r-- M 21470 ehg web   73 May 21 18:17 /usr/web/save/t.html*/#include <u.h>#include <libc.h>#include <bio.h>#include "httpd.h"#include "httpsrv.h" enum{	MaxLog		= 24*1024,		/* limit on length of any one log request */	LockSecs	= MaxLog/500,		/* seconds to wait before giving up on opening the data file */}; static intdangerous(char *s){	if(s == nil)		return 1; 	/*	 * This check shouldn't be needed;	 * filename folding is already supposed to have happened.	 * But I'm paranoid.	 */	while(s = strchr(s,'/')){		if(s[1]=='.' && s[2]=='.')			return 1;		s++;	}	return 0;} /* * open a file which might be locked. * if it is, spin until available */intopenLocked(char *file, int mode){	char buf[ERRMAX];	int tries, fd; 	for(tries = 0; tries < LockSecs*2; tries++){		fd = open(file, mode);		if(fd >= 0)			return fd;		errstr(buf, sizeof buf);		if(strstr(buf, "locked") == nil)			break;		sleep(500);	}	return -1;} voidmain(int argc, char **argv){	HConnect *c;	Dir *dir;	Hio *hin, *hout;	char *s, *t, *fn;	int n, nfn, datafd, htmlfd; 	c = init(argc, argv); 	if(dangerous(c->req.uri)){		hfail(c, HSyntax);		exits("failed");	} 	if(hparseheaders(c, HSTIMEOUT) < 0)		exits("failed");	hout = &c->hout;	if(c->head.expectother){		hfail(c, HExpectFail, nil);		exits("failed");	}	if(c->head.expectcont){		hprint(hout, "100 Continue\r\n");		hprint(hout, "\r\n");		hflush(hout);	} 	s = nil;	if(strcmp(c->req.meth, "POST") == 0){		hin = hbodypush(&c->hin, c->head.contlen, c->head.transenc);		if(hin != nil){			alarm(HSTIMEOUT);			s = hreadbuf(hin, hin->pos);			alarm(0);		}		if(s == nil){			hfail(c, HBadReq, nil);			exits("failed");		}		t = strchr(s, '\n');		if(t != nil)			*t = '\0';	}else if(strcmp(c->req.meth, "GET") != 0 && strcmp(c->req.meth, "HEAD") != 0){		hunallowed(c, "GET, HEAD, PUT");		exits("unallowed");	}else		s = c->req.search;	if(s == nil){		hfail(c, HNoData, "save");		exits("failed");	} 	if(strlen(s) > MaxLog)		s[MaxLog] = '\0';	n = snprint(c->xferbuf, HBufSize, "at %ld %s\n", time(0), s);  	nfn = strlen(c->req.uri) + 64;	fn = halloc(c, nfn); 	/*	 * open file descriptors & write log line	 */	snprint(fn, nfn, "/usr/web/save/%s.html", c->req.uri);	htmlfd = open(fn, OREAD);	if(htmlfd < 0 || (dir = dirfstat(htmlfd)) == nil){		hfail(c, HNotFound, c->req.uri);		exits("failed");		return;	} 	snprint(fn, nfn, "/usr/web/save/%s.data", c->req.uri);	datafd = openLocked(fn, OWRITE);	if(datafd < 0){		errstr(c->xferbuf, sizeof c->xferbuf);		if(strstr(c->xferbuf, "locked") != nil)			hfail(c, HTempFail, c->req.uri);		else			hfail(c, HNotFound, c->req.uri);		exits("failed");	}	seek(datafd, 0, 2);	write(datafd, c->xferbuf, n);	close(datafd); 	sendfd(c, htmlfd, dir, hmkcontent(c, "text", "html", nil), nil); 	exits(nil);}