#include "logfsos.h"#include "logfs.h"#include "local.h" char *logfsserveropen(LogfsServer *server, u32int fid, uchar mode, Qid *qid){	Fid *f;	Entry *e;	ulong modemask; 	if(server->trace > 1)		print("logfsserveropen(%ud, %d)\n",  fid, mode);	f = logfsfidmapfindentry(server->fidmap, fid);	if(f == nil)		return logfsebadfid;	if(f->openmode >= 0)		return logfsefidopen;	e = f->entry;	SET(modemask);	switch(mode & 3) {	case OEXEC:		modemask = DMEXEC;		break;	case OREAD:		modemask = DMREAD;		break;	case OWRITE:		modemask = DMWRITE;		break;	case ORDWR:		modemask = DMWRITE | DMREAD;		break;	}	if(e->qid.type & QTDIR) {		if((modemask & DMWRITE) != 0 || (mode & (ORCLOSE | OTRUNC)) != 0)			return Eperm;	}	else {		if(mode & OTRUNC)			modemask |= DMWRITE;		if((mode & ORCLOSE) != 0 && !logfsuserpermcheck(server, e->parent, f, DMWRITE))			return Eperm;	}	if(!logfsuserpermcheck(server, e, f, modemask))		return Eperm;	if((e->qid.type & QTDIR) == 0 && (mode & OTRUNC) != 0 && (e->perm & DMAPPEND) == 0 && e->u.file.length != 0) {		LogMessage s;		char *errmsg;		s.type = LogfsLogTtrunc;		s.path = e->qid.path;		s.u.trunc.mtime = logfsnow();		s.u.trunc.cvers = e->u.file.cvers + 1;		s.u.trunc.muid = logfsisfindidfromname(server->is, f->uname);		errmsg = logfslog(server, 1, &s);		if(errmsg)			return errmsg;		e->muid = s.u.trunc.muid;		e->mtime = s.u.trunc.mtime;		e->qid.vers++;		e->u.file.cvers = s.u.trunc.cvers;		/*		 * zap all data and extents		 */		logfsextentlistwalk(e->u.file.extent, logfsunconditionallymarkfreeanddirty, server);		logfsextentlistreset(e->u.file.extent);		e->u.file.length = 0;	}	f->openmode = mode;	*qid = e->qid;	return nil;}