x20090325-1554

1 files changed, 2504 insertions, 0 deletions

diff --git a/emu/Nt/devfs.c b/emu/Nt/devfs.c
new file mode 100644
index 00000000..89d52e83
--- /dev/null
+++ b/emu/Nt/devfs.c
@@ -0,0 +1,2504 @@
+#define UNICODE
+#define Unknown win_Unknown
+#include	<windows.h>
+#include	<winbase.h>
+#undef Unknown
+#undef	Sleep
+#include	"dat.h"
+#include	"fns.h"
+#include	"error.h"
+#include	<lm.h>
+
+/* TODO: try using / in place of \ in path names */
+
+enum
+{
+	MAX_SID		= sizeof(SID) + SID_MAX_SUB_AUTHORITIES*sizeof(DWORD),
+	ACL_ROCK	= sizeof(ACL) + 20*(sizeof(ACCESS_ALLOWED_ACE)+MAX_SID),
+	SD_ROCK		= SECURITY_DESCRIPTOR_MIN_LENGTH + MAX_SID + ACL_ROCK,
+	MAXCOMP		= 128,
+};
+
+typedef struct	User	User;
+typedef struct  Gmem	Gmem;
+typedef	struct	Stat	Stat;
+typedef	struct Fsinfo	Fsinfo;
+typedef	WIN32_FIND_DATA	Fsdir;
+
+#ifndef INVALID_SET_FILE_POINTER
+#define	INVALID_SET_FILE_POINTER	((DWORD)-1)
+#endif
+
+struct Fsinfo
+{
+	int	uid;
+	int	gid;
+	int	mode;
+	int	fd;
+	vlong	offset;
+	QLock	oq;
+	char*	spec;
+	Rune*	srv;
+	Cname*	name;	/* Windows' idea of the file name */
+	ushort	usesec;
+	ushort	checksec;
+	Fsdir*	de;	/* non-nil for saved entry from last dirread at offset */
+};
+#define	FS(c)	((Fsinfo*)(c)->aux)
+
+/*
+ * info about a user or group
+ * there are two ways to specify a user:
+ *	by sid, a unique identifier
+ *	by user and domain names
+ * this structure is used to convert between the two,
+ * as well as figure out which groups a users belongs to.
+ * the user information never gets thrown away,
+ * but the group information gets refreshed with each setid.
+ */
+struct User
+{
+	QLock	lk;		/* locks the gotgroup and group fields */
+	SID	*sid;
+	Rune	*name;
+	Rune	*dom;
+	int	type;		/* the type of sid, ie SidTypeUser, SidTypeAlias, ... */
+	int	gotgroup;	/* tried to add group */
+	Gmem	*group;		/* global and local groups to which this user or group belongs. */
+	User	*next;
+};
+
+struct Gmem
+{
+	User	*user;
+	Gmem	*next;
+};
+
+/*
+ * intermediate stat information
+ */
+struct Stat
+{
+	User	*owner;
+	User	*group;
+	ulong	mode;
+};
+
+/*
+ * some "well-known" sids
+ */
+static	SID	*creatorowner;
+static	SID	*creatorgroup;
+static	SID	*everyone;
+static	SID	*ntignore;
+static	SID	*ntroot;	/* user who is supposed to run emu as a server */
+
+/*
+ * all users we ever see end up in this table
+ * users are never deleted, but we should update
+ * group information for users sometime
+ */
+static struct
+{
+	QLock	lk;
+	User	*u;
+}users;
+
+/*
+ * conversion from inferno permission modes to nt access masks
+ * is this good enough?  this is what nt sets, except for NOMODE
+ */
+#define	NOMODE	(READ_CONTROL|FILE_READ_EA|FILE_READ_ATTRIBUTES)
+#define	RMODE	(READ_CONTROL|SYNCHRONIZE\
+		|FILE_READ_DATA|FILE_READ_EA|FILE_READ_ATTRIBUTES)
+#define	XMODE	(READ_CONTROL|SYNCHRONIZE\
+		|FILE_EXECUTE|FILE_READ_ATTRIBUTES)
+#define	WMODE	(DELETE|READ_CONTROL|SYNCHRONIZE|WRITE_DAC|WRITE_OWNER\
+		|FILE_WRITE_DATA|FILE_APPEND_DATA|FILE_WRITE_EA\
+		|FILE_DELETE_CHILD|FILE_WRITE_ATTRIBUTES)
+
+static	int
+modetomask[] =
+{
+	NOMODE,
+	XMODE,
+	WMODE,
+	WMODE|XMODE,
+	RMODE,
+	RMODE|XMODE,
+	RMODE|WMODE,
+	RMODE|WMODE|XMODE,
+};
+
+extern	DWORD	PlatformId;
+	char    rootdir[MAXROOT] = "\\inferno";
+	Rune	rootname[] = L"inferno-server";
+static	Qid	rootqid;
+static	User	*fsnone;
+static	User	*fsuser;
+static	Rune	*ntsrv;
+static	int	usesec;
+static	int	checksec;
+static	int	isserver;
+static	int	file_share_delete;
+static	uchar	isntfrog[256];
+
+static	void		fsremove(Chan*);
+
+	wchar_t	*widen(char *s);
+	char		*narrowen(wchar_t *ws);
+	int		widebytes(wchar_t *ws);
+
+static char Etoolong[] = "file name too long";
+
+/*
+ * these lan manager functions are not supplied
+ * on windows95, so we have to load the dll by hand
+ */
+static struct {
+	NET_API_STATUS (NET_API_FUNCTION *UserGetLocalGroups)(
+		LPWSTR servername,
+		LPWSTR username,
+		DWORD level,
+		DWORD flags,
+		LPBYTE *bufptr,
+		DWORD prefmaxlen,
+		LPDWORD entriesread,
+		LPDWORD totalentries);
+	NET_API_STATUS (NET_API_FUNCTION *UserGetGroups)(
+		LPWSTR servername,
+		LPWSTR username,
+		DWORD level,
+		LPBYTE *bufptr,
+		DWORD prefmaxlen,
+		LPDWORD entriesread,
+		LPDWORD totalentries);
+	NET_API_STATUS (NET_API_FUNCTION *GetAnyDCName)(
+		LPCWSTR ServerName,
+		LPCWSTR DomainName,
+		LPBYTE *Buffer);
+	NET_API_STATUS (NET_API_FUNCTION *ApiBufferFree)(LPVOID Buffer);
+} net;
+
+extern	int		nth2fd(HANDLE);
+extern	HANDLE		ntfd2h(int);
+static	int		cnisroot(Cname*);
+static	int		fsisroot(Chan*);
+static	int		okelem(char*, int);
+static	int		fsexist(char*, Qid*);
+static	char*	fspath(Cname*, char*, char*, char*);
+static	Cname*	fswalkpath(Cname*, char*, int);
+static	char*	fslastelem(Cname*);
+static	long		fsdirread(Chan*, uchar*, int, vlong);
+static	ulong		fsqidpath(char*);
+static	int		fsomode(int);
+static	int		fsdirset(char*, int, WIN32_FIND_DATA*, char*, Chan*, int isdir);
+static 	int		fsdirsize(WIN32_FIND_DATA*, char*, Chan*);
+static	void		fssettime(char*, long, long);
+static	long		unixtime(FILETIME);
+static	FILETIME	wintime(ulong);
+static	void		secinit(void);
+static	int		secstat(Dir*, char*, Rune*);
+static	int		secsize(char*, Rune*);
+static	void		seccheck(char*, ulong, Rune*);
+static	int		sechasperm(char*, ulong, Rune*);
+static	SECURITY_DESCRIPTOR* secsd(char*, char[SD_ROCK]);
+static	int		secsdhasperm(SECURITY_DESCRIPTOR*, ulong, Rune*);
+static	int		secsdstat(SECURITY_DESCRIPTOR*, Stat*, Rune*);
+static	SECURITY_DESCRIPTOR* secmksd(char[SD_ROCK], Stat*, ACL*, int);
+static	SID		*dupsid(SID*);
+static	int		ismembersid(Rune*, User*, SID*);
+static	int		ismember(User*, User*);
+static	User		*sidtouser(Rune*, SID*);
+static	User		*domnametouser(Rune*, Rune*, Rune*);
+static	User		*nametouser(Rune*, Rune*);
+static	User		*unametouser(Rune*, char*);
+static	void		addgroups(User*, int);
+static	User		*mkuser(SID*, int, Rune*, Rune*);
+static	Rune		*domsrv(Rune *, Rune[MAX_PATH]);
+static	Rune		*filesrv(char*);
+static	int		fsacls(char*);
+static	User		*secuser(void);
+
+	int		runeslen(Rune*);
+	Rune*		runesdup(Rune*);
+	Rune*		utftorunes(Rune*, char*, int);
+	char*		runestoutf(char*, Rune*, int);
+	int		runescmp(Rune*, Rune*);
+
+
+int
+winfilematch(char *path, WIN32_FIND_DATA *data)
+{
+	char *p;
+	wchar_t *wpath;
+	int r;
+
+	p = path+strlen(path);
+	while(p > path && p[-1] != '\\')
+		--p;
+	wpath = widen(p);
+	r = (data->cFileName[0] == '.' && runeslen(data->cFileName) == 1)
+			|| runescmp(data->cFileName, wpath) == 0;
+	free(wpath);
+	return r;
+}
+
+int
+winfileclash(char *path)
+{
+	HANDLE h;
+	WIN32_FIND_DATA data;
+	wchar_t *wpath;
+
+	wpath = widen(path);
+	h = FindFirstFile(wpath, &data);
+	free(wpath);
+	if (h != INVALID_HANDLE_VALUE) {
+		FindClose(h);
+		return !winfilematch(path, &data);
+	}
+	return 0;
+}
+
+
+/*
+ * this gets called to set up the environment when we switch users
+ */
+void
+setid(char *name, int owner)
+{
+	User *u;
+
+	if(owner && !iseve())
+		return;
+
+	kstrdup(&up->env->user, name);
+
+	if(!usesec)
+		return;
+
+	u = unametouser(ntsrv, up->env->user);
+	if(u == nil)
+		u = fsnone;
+	else {
+		qlock(&u->lk);
+		addgroups(u, 1);
+		qunlock(&u->lk);
+	}
+	if(u == nil)
+		panic("setid: user nil\n");
+
+	up->env->ui = u;
+}
+
+static void
+fsfree(Chan *c)
+{
+	cnameclose(FS(c)->name);
+	if(FS(c)->de != nil)
+		free(FS(c)->de);
+	free(FS(c));
+}
+
+void
+fsinit(void)
+{
+	int n, isvol;
+	ulong attr;
+	char *p, tmp[MAXROOT];
+	wchar_t *wp, *wpath, *last;
+	wchar_t wrootdir[MAXROOT];
+
+	isntfrog['/'] = 1;
+	isntfrog['\\'] = 1;
+	isntfrog[':'] = 1;
+	isntfrog['*'] = 1;
+	isntfrog['?'] = 1;
+	isntfrog['"'] = 1;
+	isntfrog['<'] = 1;
+	isntfrog['>'] = 1;
+
+	/*
+	 * vet the root
+	 */
+	strcpy(tmp, rootdir);
+	for(p = tmp; *p; p++)
+		if(*p == '/')
+			*p = '\\';
+	if(tmp[0] != 0 && tmp[1] == ':') {
+		if(tmp[2] == 0) {
+			tmp[2] = '\\';
+			tmp[3] = 0;
+		}
+		else if(tmp[2] != '\\') {
+			/* don't allow c:foo - only c:\foo */
+			panic("illegal root pathX");
+		}
+	}
+	wrootdir[0] = '\0';
+	wpath = widen(tmp);
+	for(wp = wpath; *wp; wp++) {
+		if(*wp < 32 || (*wp < 256 && isntfrog[*wp] && *wp != '\\' && *wp != ':'))
+			panic("illegal root path");
+	}
+	n = GetFullPathName(wpath, MAXROOT, wrootdir, &last);
+	free(wpath);	
+	runestoutf(rootdir, wrootdir, MAXROOT);
+	if(n >= MAXROOT || n == 0)
+		panic("illegal root path");
+
+	/* get rid of trailing \ */
+	while(rootdir[n-1] == '\\') {
+		if(n <= 2) {
+			panic("illegal root path");
+		}
+		rootdir[--n] = '\0';
+	}
+
+	isvol = 0;
+	if(rootdir[1] == ':' && rootdir[2] == '\0')
+		isvol = 1;
+	else if(rootdir[0] == '\\' && rootdir[1] == '\\') {
+		p = strchr(&rootdir[2], '\\');
+		if(p == nil)
+			panic("inferno root can't be a server");
+		isvol = strchr(p+1, '\\') == nil;
+	}
+
+	if(strchr(rootdir, '\\') == nil)
+		strcat(rootdir, "\\.");
+	attr = GetFileAttributes(wrootdir);
+	if(attr == 0xFFFFFFFF)
+		panic("root path '%s' does not exist", narrowen(wrootdir));
+	rootqid.path = fsqidpath(rootdir);
+	if(attr & FILE_ATTRIBUTE_DIRECTORY)
+		rootqid.type |= QTDIR;
+	rootdir[n] = '\0';
+
+	rootqid.vers = time(0);
+
+	/*
+	 * set up for nt file security checking
+	 */
+	ntsrv = filesrv(rootdir);
+	usesec = PlatformId == VER_PLATFORM_WIN32_NT; 	/* true for NT and 2000 */
+	if(usesec){
+		file_share_delete = FILE_SHARE_DELETE;	/* sensible handling of shared files by delete and rename */
+		secinit();
+		if(!fsacls(rootdir))
+			usesec = 0;
+	}
+	checksec = usesec && isserver;
+}
+
+Chan*
+fsattach(char *spec)
+{
+	Chan *c;
+	static int devno;
+	static Lock l;
+	char *drive = (char *)spec;
+
+	if (!emptystr(drive) && (drive[1] != ':' || drive[2] != '\0'))
+		error(Ebadspec);
+
+	c = devattach('U', spec);
+	lock(&l);
+	c->dev = devno++;
+	unlock(&l);
+	c->qid = rootqid;
+	c->aux = smalloc(sizeof(Fsinfo));
+	FS(c)->srv = ntsrv;
+	if(!emptystr(spec)) {
+		char *s = smalloc(strlen(spec)+1);
+		strcpy(s, spec);
+		FS(c)->spec = s;
+		FS(c)->srv = filesrv(spec);
+		if(usesec)
+			FS(c)->usesec = fsacls(spec);
+		FS(c)->checksec = FS(c)->usesec && isserver;
+		c->qid.path = fsqidpath(spec);
+		c->qid.type = QTDIR;
+		c->qid.vers = 0;
+	}else{
+		FS(c)->usesec = usesec;
+		FS(c)->checksec = checksec;
+	}
+	FS(c)->name = newcname("/");
+	return c;
+}
+
+Walkqid*
+fswalk(Chan *c, Chan *nc, char **name, int nname)
+{
+	int j, alloc;
+	Walkqid *wq;
+	char path[MAX_PATH], *p;
+	Cname *ph;
+	Cname *current, *next;
+
+	if(nname > 0)
+		isdir(c);
+
+	alloc = 0;
+	current = nil;
+	wq = smalloc(sizeof(Walkqid)+(nname-1)*sizeof(Qid));
+	if(waserror()){
+		if(alloc && wq->clone != nil)
+			cclose(wq->clone);
+		cnameclose(current);
+		free(wq);
+		return nil;
+	}
+	if(nc == nil){
+		nc = devclone(c);
+		nc->type = 0;
+		alloc = 1;
+	}
+	wq->clone = nc;
+	current = FS(c)->name;
+	if(current != nil)
+		incref(&current->r);
+	for(j = 0; j < nname; j++){
+		if(!(nc->qid.type&QTDIR)){
+			if(j==0)
+				error(Enotdir);
+			break;
+		}
+		if(!okelem(name[j], 0)){
+			if(j == 0)
+				error(Efilename);
+			break;
+		}
+		p = fspath(current, name[j], path, FS(c)->spec);
+		if(FS(c)->checksec) {
+			*p = '\0';
+			if(!sechasperm(path, XMODE, FS(c)->srv)){
+				if(j == 0)
+					error(Eperm);
+				break;
+			}
+			*p = '\\';
+		}
+
+		if(strcmp(name[j], "..") == 0) {
+			if(fsisroot(c))
+				nc->qid = rootqid;
+			else{
+				ph = fswalkpath(current, "..", 1);
+				if(cnisroot(ph)){
+					nc->qid = rootqid;
+					current = ph;
+					if(current != nil)
+						incref(&current->r);
+				}
+				else {
+					fspath(ph, 0, path, FS(c)->spec);
+					if(!fsexist(path, &nc->qid)){
+						cnameclose(ph);
+						if(j == 0)
+							error(Enonexist);
+						break;
+					}
+				}
+				next = fswalkpath(current, name[j], 1);
+				cnameclose(current);
+				current = next;
+				cnameclose(ph);
+			}
+		}
+		else{
+			if(!fsexist(path, &nc->qid)){
+				if(j == 0)
+					error(Enonexist);
+				break;
+			}
+			next = fswalkpath(current, name[j], 1);
+			cnameclose(current);
+			current = next;
+		}
+		wq->qid[wq->nqid++] = nc->qid;
+	}
+	poperror();
+	if(wq->nqid < nname){
+		cnameclose(current);
+		if(alloc)
+			cclose(wq->clone);
+		wq->clone = nil;
+	}else if(wq->clone){
+		nc->aux = smalloc(sizeof(Fsinfo));
+		nc->type = c->type;
+		FS(nc)->spec = FS(c)->spec;
+		FS(nc)->srv = FS(c)->srv;
+		FS(nc)->name = current;
+		FS(nc)->usesec = FS(c)->usesec;
+		FS(nc)->checksec = FS(c)->checksec;
+	}
+	return wq;
+}
+
+Chan*
+fsopen(Chan *c, int mode)
+{
+	HANDLE h;
+	int m, isdir, aflag, cflag;
+	char path[MAX_PATH];
+	wchar_t *wpath;
+
+	isdir = c->qid.type & QTDIR;
+	if(isdir && mode != OREAD)
+		error(Eperm);
+	fspath(FS(c)->name, 0, path, FS(c)->spec);
+
+	if(FS(c)->checksec) {
+		switch(mode & (OTRUNC|3)) {
+		case OREAD:
+			seccheck(path, RMODE, FS(c)->srv);
+			break;
+		case OWRITE:
+		case OWRITE|OTRUNC:
+			seccheck(path, WMODE, FS(c)->srv);
+			break;
+		case ORDWR:
+		case ORDWR|OTRUNC:
+		case OREAD|OTRUNC:
+			seccheck(path, RMODE|WMODE, FS(c)->srv);
+			break;
+		case OEXEC:
+			seccheck(path, XMODE, FS(c)->srv);
+			break;
+		default:
+			error(Ebadarg);
+		}
+	}
+
+	c->mode = openmode(mode);
+	if(isdir)
+		FS(c)->fd = nth2fd(INVALID_HANDLE_VALUE);
+	else {
+		m = fsomode(mode & 3);
+		cflag = OPEN_EXISTING;
+		if(mode & OTRUNC)
+			cflag = TRUNCATE_EXISTING;
+		aflag = FILE_FLAG_RANDOM_ACCESS;
+		if(mode & ORCLOSE)
+			aflag |= FILE_FLAG_DELETE_ON_CLOSE;
+		if (winfileclash(path))
+			error(Eexist);
+		wpath = widen(path);
+		h = CreateFile(wpath, m, FILE_SHARE_READ|FILE_SHARE_WRITE|file_share_delete, 0, cflag, aflag, 0);
+		free(wpath);
+		if(h == INVALID_HANDLE_VALUE)
+			oserror();
+		FS(c)->fd = nth2fd(h);
+	}
+
+	c->offset = 0;
+	FS(c)->offset = 0;
+	c->flag |= COPEN;
+	return c;
+}
+
+void
+fscreate(Chan *c, char *name, int mode, ulong perm)
+{
+	Stat st;
+	HANDLE h;
+	int m, aflag;
+	SECURITY_ATTRIBUTES sa;
+	SECURITY_DESCRIPTOR *sd;
+	BY_HANDLE_FILE_INFORMATION hi;
+	char *p, path[MAX_PATH], sdrock[SD_ROCK];
+	wchar_t *wpath;
+	ACL *acl;
+
+	if(!okelem(name, 1))
+		error(Efilename);
+
+	m = fsomode(mode & 3);
+	p = fspath(FS(c)->name, name, path, FS(c)->spec);
+	acl = (ACL*)smalloc(ACL_ROCK);
+	sd = nil;
+	if(FS(c)->usesec) {
+		*p = '\0';
+		sd = secsd(path, sdrock);
+		*p = '\\';
+		if(sd == nil){
+			free(acl);
+			oserror();
+		}
+		if(FS(c)->checksec && !secsdhasperm(sd, WMODE, FS(c)->srv)
+		|| !secsdstat(sd, &st, FS(c)->srv)){
+			if(sd != (void*)sdrock)
+				free(sd);
+			free(acl);
+			error(Eperm);
+		}
+		if(sd != (void*)sdrock)
+			free(sd);
+		if(perm & DMDIR)
+			st.mode = (perm & ~0777) | (st.mode & perm & 0777);
+		else
+			st.mode = (perm & ~0666) | (st.mode & perm & 0666);
+		st.owner = up->env->ui;
+		if(!isserver)
+			st.owner = fsuser;
+		sd = secmksd(sdrock, &st, acl, perm & DMDIR);
+		if(sd == nil){
+			free(acl);
+			oserror();
+		}
+	}
+	sa.nLength = sizeof(sa);
+	sa.lpSecurityDescriptor = sd;
+	sa.bInheritHandle = 0;
+
+	if(perm & DMDIR) {
+		if(mode != OREAD) {
+			free(acl);
+			error(Eisdir);
+		}
+		wpath = widen(path);
+		if(!CreateDirectory(wpath, &sa) || !fsexist(path, &c->qid)) {
+			free(wpath);
+			free(acl);
+			oserror();
+		}
+		free(wpath);
+		FS(c)->fd = nth2fd(INVALID_HANDLE_VALUE);
+	}
+	else {
+		aflag = 0;
+		if(mode & ORCLOSE)
+			aflag = FILE_FLAG_DELETE_ON_CLOSE;
+		if (winfileclash(path))
+			error(Eexist);
+		wpath = widen(path);
+		h = CreateFile(wpath, m, FILE_SHARE_READ|FILE_SHARE_WRITE|file_share_delete, &sa, CREATE_ALWAYS, aflag, 0);
+		free(wpath);
+		if(h == INVALID_HANDLE_VALUE) {
+			free(acl);
+			oserror();
+		}
+		FS(c)->fd = nth2fd(h);
+		c->qid.path = fsqidpath(path);
+		c->qid.type = 0;
+		c->qid.vers = 0;
+		if(GetFileInformationByHandle(h, &hi))
+			c->qid.vers = unixtime(hi.ftLastWriteTime);
+	}
+
+	c->mode = openmode(mode);
+	c->offset = 0;
+	FS(c)->offset = 0;
+	c->flag |= COPEN;
+	FS(c)->name = fswalkpath(FS(c)->name, name, 0);
+	free(acl);
+}
+
+void
+fsclose(Chan *c)
+{
+	HANDLE h;
+
+	if(c->flag & COPEN){
+		h = ntfd2h(FS(c)->fd);
+		if(h != INVALID_HANDLE_VALUE){
+			if(c->qid.type & QTDIR)
+				FindClose(h);
+			else
+				CloseHandle(h);
+		}
+	}
+	if(c->flag & CRCLOSE){
+		if(!waserror()){
+			fsremove(c);
+			poperror();
+		}
+		return;
+	}
+	fsfree(c);
+}
+
+/*
+ * 64-bit seeks, using SetFilePointer because SetFilePointerEx
+ * is not supported by NT
+ */
+static void
+fslseek(HANDLE h, vlong offset)
+{
+	LONG hi;
+
+	if(offset <= 0x7fffffff){
+		if(SetFilePointer(h, (LONG)offset, NULL, FILE_BEGIN) == INVALID_SET_FILE_POINTER)
+			oserror();
+	}else{
+		hi = offset>>32;
+		if(SetFilePointer(h, (LONG)offset, &hi, FILE_BEGIN) == INVALID_SET_FILE_POINTER &&
+		   GetLastError() != NO_ERROR)
+			oserror();
+	}
+}
+
+long
+fsread(Chan *c, void *va, long n, vlong offset)
+{
+	DWORD n2;
+	HANDLE h;
+
+	qlock(&FS(c)->oq);
+	if(waserror()){
+		qunlock(&FS(c)->oq);
+		nexterror();
+	}
+	if(c->qid.type & QTDIR) {
+		n2 = fsdirread(c, va, n, offset);
+	}
+	else {
+		h = ntfd2h(FS(c)->fd);
+		if(FS(c)->offset != offset){
+			fslseek(h, offset);
+			FS(c)->offset = offset;
+		}
+		if(!ReadFile(h, va, n, &n2, NULL))
+			oserror();
+		FS(c)->offset += n2;
+	}
+	qunlock(&FS(c)->oq);
+	poperror();
+	return n2;
+}
+
+long
+fswrite(Chan *c, void *va, long n, vlong offset)
+{
+	DWORD n2;
+	HANDLE h;
+
+	qlock(&FS(c)->oq);
+	if(waserror()){
+		qunlock(&FS(c)->oq);
+		nexterror();
+	}
+	h = ntfd2h(FS(c)->fd);
+	if(FS(c)->offset != offset){
+		fslseek(h, offset);
+		FS(c)->offset = offset;
+	}
+	if(!WriteFile(h, va, n, &n2, NULL))
+		oserror();
+	FS(c)->offset += n2;
+	qunlock(&FS(c)->oq);
+	poperror();
+	return n2;
+}
+
+int
+fsstat(Chan *c, uchar *buf, int n)
+{
+	WIN32_FIND_DATA data;
+	char path[MAX_PATH];
+	wchar_t *wpath;
+
+	/*
+	 * have to fake up a data for volumes like
+	 * c: and \\server\share since you can't FindFirstFile them
+	 */
+	if(fsisroot(c)){
+		strcpy(path, rootdir);
+		if(strchr(path, '\\') == nil)
+			strcat(path, "\\.");
+		wpath = widen(path);
+		data.dwFileAttributes = GetFileAttributes(wpath);
+		free(wpath);
+		if(data.dwFileAttributes == 0xffffffff)
+			oserror();
+		data.ftCreationTime =
+		data.ftLastAccessTime =
+		data.ftLastWriteTime = wintime(time(0));
+		data.nFileSizeHigh = 0;
+		data.nFileSizeLow = 0;
+		utftorunes(data.cFileName, ".", MAX_PATH);
+	} else {
+		HANDLE h = INVALID_HANDLE_VALUE;
+
+		fspath(FS(c)->name, 0, path, FS(c)->spec);
+		if (c->flag & COPEN)
+			h = ntfd2h(FS(c)->fd);
+
+		if (h != INVALID_HANDLE_VALUE) {
+			BY_HANDLE_FILE_INFORMATION fi;
+			if (c->mode & OWRITE)
+				FlushFileBuffers(h);
+			if (!GetFileInformationByHandle(h, &fi))
+				oserror();
+			data.dwFileAttributes = fi.dwFileAttributes;
+			data.ftCreationTime = fi.ftCreationTime;
+			data.ftLastAccessTime = fi.ftLastAccessTime;
+			data.ftLastWriteTime = fi.ftLastWriteTime;;
+			data.nFileSizeHigh = fi.nFileSizeHigh;
+			data.nFileSizeLow = fi.nFileSizeLow;
+		} else {
+			wpath = widen(path);
+			h = FindFirstFile(wpath, &data);
+			free(wpath);
+			if(h == INVALID_HANDLE_VALUE)
+				oserror();
+			if (!winfilematch(path, &data)) {
+				FindClose(h);
+				error(Enonexist);
+			}
+			FindClose(h);
+		}
+		utftorunes(data.cFileName, fslastelem(FS(c)->name), MAX_PATH);
+	}
+
+	return fsdirset(buf, n, &data, path, c, 0);
+}
+
+int
+fswstat(Chan *c, uchar *buf, int n)
+{
+	int wsd;
+	Dir dir;
+	Stat st;
+	Cname * volatile ph;
+	HANDLE h;
+	ulong attr;
+	User *ou, *gu;
+	WIN32_FIND_DATA data;
+	SECURITY_DESCRIPTOR *sd;
+	char *last, sdrock[SD_ROCK], path[MAX_PATH], newpath[MAX_PATH], strs[4*256];
+	wchar_t wspath[MAX_PATH], wsnewpath[MAX_PATH];
+	wchar_t *wpath;
+	int nmatch;
+
+	n = convM2D(buf, n, &dir, strs);
+	if(n == 0)
+		error(Eshortstat);
+
+	last = fspath(FS(c)->name, 0, path, FS(c)->spec);
+	utftorunes(wspath, path, MAX_PATH);
+
+	if(fsisroot(c)){
+		if(dir.atime != ~0)
+			data.ftLastAccessTime = wintime(dir.atime);
+		if(dir.mtime != ~0)
+			data.ftLastWriteTime = wintime(dir.mtime);
+		utftorunes(data.cFileName, ".", MAX_PATH);
+	}else{
+		h = FindFirstFile(wspath, &data);
+		if(h == INVALID_HANDLE_VALUE)
+			oserror();
+		if (!winfilematch(path, &data)) {
+			FindClose(h);
+			error(Enonexist);
+		}
+		FindClose(h);
+	}
+
+	wsd = 0;
+	ou = nil;
+	gu = nil;
+	if(FS(c)->usesec) {
+		if(FS(c)->checksec && up->env->ui == fsnone)
+			error(Eperm);
+
+		/*
+		 * find new owner and group
+		 */
+		if(!emptystr(dir.uid)){
+			ou = unametouser(FS(c)->srv, dir.uid);
+			if(ou == nil)
+				oserror();
+		}
+		if(!emptystr(dir.gid)){
+			gu = unametouser(FS(c)->srv, dir.gid);
+			if(gu == nil){
+				if(strcmp(dir.gid, "unknown") != 0
+				&& strcmp(dir.gid, "deleted") != 0)
+					oserror();
+				gu = ou;
+			}
+		}
+
+		/*
+		 * find old stat info
+		 */
+		sd = secsd(path, sdrock);
+		if(sd == nil || !secsdstat(sd, &st, FS(c)->srv)){
+			if(sd != nil && sd != (void*)sdrock)
+				free(sd);
+			oserror();
+		}
+		if(sd != (void*)sdrock)
+			free(sd);
+
+		/*
+		 * permission rules:
+		 * if none, can't do anything
+		 * chown => no way
+		 * chgrp => current owner or group, and in new group
+		 * mode/time => owner or in either group
+		 * rename => write in parent
+		 */
+		if(ou == nil)
+			ou = st.owner;
+		if(FS(c)->checksec && st.owner != ou)
+			error(Eperm);
+
+		if(gu == nil)
+			gu = st.group;
+		if(st.group != gu){
+			if(FS(c)->checksec
+			&&(!ismember(up->env->ui, ou) && !ismember(up->env->ui, gu)
+			|| !ismember(up->env->ui, st.group)))
+				error(Eperm);
+			wsd = 1;
+		}
+
+		if(dir.atime != ~0 && unixtime(data.ftLastAccessTime) != dir.atime
+		|| dir.mtime != ~0 && unixtime(data.ftLastWriteTime) != dir.mtime
+		|| dir.mode != ~0 && st.mode != dir.mode){
+			if(FS(c)->checksec
+			&& !ismember(up->env->ui, ou)
+			&& !ismember(up->env->ui, gu)
+			&& !ismember(up->env->ui, st.group))
+				error(Eperm);
+			if(dir.mode != ~0 && st.mode != dir.mode)
+				wsd = 1;
+		}
+	}
+	wpath = widen(dir.name);
+	nmatch = runescmp(wpath, data.cFileName);
+	free(wpath);
+	if(!emptystr(dir.name) && nmatch != 0){
+		if(!okelem(dir.name, 1))
+			error(Efilename);
+		ph = fswalkpath(FS(c)->name, "..", 1);
+		if(waserror()){
+			cnameclose(ph);
+			nexterror();
+		}
+		ph = fswalkpath(ph, dir.name, 0);
+		fspath(ph, 0, newpath, FS(c)->spec);
+		utftorunes(wsnewpath, newpath, MAX_PATH);
+		if(GetFileAttributes(wpath) != 0xffffffff && !winfileclash(newpath))
+			error("file already exists");
+		if(fsisroot(c))
+			error(Eperm);
+		if(FS(c)->checksec){
+			*last = '\0';
+			seccheck(path, WMODE, FS(c)->srv);
+			*last = '\\';
+		}
+		poperror();
+		cnameclose(ph);
+	}
+
+	if(dir.atime != ~0 && unixtime(data.ftLastAccessTime) != dir.atime
+	|| dir.mtime != ~0 && unixtime(data.ftLastWriteTime) != dir.mtime)
+		fssettime(path, dir.atime, dir.mtime);
+
+	attr = data.dwFileAttributes;
+	if(dir.mode & 0222)
+		attr &= ~FILE_ATTRIBUTE_READONLY;
+	else
+		attr |= FILE_ATTRIBUTE_READONLY;
+	if(!fsisroot(c)
+	&& attr != data.dwFileAttributes
+	&& (attr & FILE_ATTRIBUTE_READONLY))
+		SetFileAttributes(wspath, attr);
+	if(FS(c)->usesec && wsd){
+		ACL *acl = (ACL *) smalloc(ACL_ROCK);
+		st.owner = ou;
+		st.group = gu;
+		if(dir.mode != ~0)
+			st.mode = dir.mode;
+		sd = secmksd(sdrock, &st, acl, data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY);
+		if(sd == nil || !SetFileSecurity(wspath, DACL_SECURITY_INFORMATION, sd)){
+			free(acl);
+			oserror();
+		}
+		free(acl);
+	}
+
+	if(!fsisroot(c)
+	&& attr != data.dwFileAttributes
+	&& !(attr & FILE_ATTRIBUTE_READONLY))
+		SetFileAttributes(wspath, attr);
+
+	/* do last so path is valid throughout */
+	wpath = widen(dir.name);
+	nmatch = runescmp(wpath, data.cFileName);
+	free(wpath);
+	if(!emptystr(dir.name) && nmatch != 0) {
+		ph = fswalkpath(FS(c)->name, "..", 1);
+		if(waserror()){
+			cnameclose(ph);
+			nexterror();
+		}
+		ph = fswalkpath(ph, dir.name, 0);
+		fspath(ph, 0, newpath, FS(c)->spec);
+		utftorunes(wsnewpath, newpath, MAX_PATH);
+		/*
+		 * can't rename if it is open: if this process has it open, close it temporarily.
+		 */
+		if(!file_share_delete && c->flag & COPEN){
+			h = ntfd2h(FS(c)->fd);
+			if(h != INVALID_HANDLE_VALUE)
+				CloseHandle(h);	/* woe betide it if ORCLOSE */
+			FS(c)->fd = nth2fd(INVALID_HANDLE_VALUE);
+		}
+		if(!MoveFile(wspath, wsnewpath)) {
+			oserror();
+		} else if(!file_share_delete && c->flag & COPEN) {
+			int	aflag;
+			SECURITY_ATTRIBUTES sa;
+			
+			/* The move succeeded, so open new file to maintain handle */
+			sa.nLength = sizeof(sa);
+			sa.lpSecurityDescriptor = sd;
+			sa.bInheritHandle = 0;
+			if(c->flag & CRCLOSE)
+				aflag = FILE_FLAG_DELETE_ON_CLOSE;
+			h = CreateFile(wsnewpath, fsomode(c->mode & 0x3), FILE_SHARE_READ|FILE_SHARE_WRITE|file_share_delete, &sa, OPEN_EXISTING, aflag, 0);
+			if(h == INVALID_HANDLE_VALUE)
+				oserror();
+			FS(c)->fd = nth2fd(h);
+		}
+		cnameclose(FS(c)->name);
+		poperror();
+		FS(c)->name = ph;
+	}
+	return n;
+}
+
+static void
+fsremove(Chan *c)
+{
+	int n;
+	char *p, path[MAX_PATH];
+	wchar_t wspath[MAX_PATH];
+
+	if(waserror()){
+		fsfree(c);
+		nexterror();
+	}
+	if(fsisroot(c))
+		error(Eperm);
+	p = fspath(FS(c)->name, 0, path, FS(c)->spec);
+	utftorunes(wspath, path, MAX_PATH);
+	if(FS(c)->checksec){
+		*p = '\0';
+		seccheck(path, WMODE, FS(c)->srv);
+		*p = '\\';
+	}
+	if(c->qid.type & QTDIR)
+		n = RemoveDirectory(wspath);
+	else
+		n = DeleteFile(wspath);
+	if (!n) {
+		ulong attr, mode;
+		SECURITY_DESCRIPTOR *sd = nil;
+		char sdrock[SD_ROCK];
+		Stat st;
+		int secok;
+		attr = GetFileAttributes(wspath);
+		if(attr != 0xFFFFFFFF) {
+			if (FS(c)->usesec) {
+				sd = secsd(path, sdrock);
+				secok = (sd != nil) && secsdstat(sd, &st, FS(c)->srv);
+				if (secok) {
+					ACL *acl = (ACL *) smalloc(ACL_ROCK);
+					mode = st.mode;
+					st.mode |= 0660;
+					sd = secmksd(sdrock, &st, acl, attr & FILE_ATTRIBUTE_DIRECTORY);
+					if(sd != nil) {
+						SetFileSecurity(wspath, DACL_SECURITY_INFORMATION, sd);
+					}
+					free(acl);
+					if(sd != nil && sd != (void*)sdrock)
+						free(sd);
+					sd = nil;
+				}
+			}
+			SetFileAttributes(wspath, FILE_ATTRIBUTE_NORMAL);
+			if(c->qid.type & QTDIR)
+				n = RemoveDirectory(wspath);
+			else
+				n = DeleteFile(wspath);
+			if (!n) {
+				if (FS(c)->usesec && secok) {
+					ACL *acl = (ACL *) smalloc(ACL_ROCK);
+					st.mode =  mode;
+					sd = secmksd(sdrock, &st, acl, attr & FILE_ATTRIBUTE_DIRECTORY);
+					if(sd != nil) {
+						SetFileSecurity(wspath, DACL_SECURITY_INFORMATION, sd);
+					}
+					free(acl);
+				}
+				SetFileAttributes(wspath, attr);
+				if(sd != nil && sd != (void*)sdrock)
+					free(sd);
+			}
+		}
+	}
+	if(!n)
+		oserror();
+	poperror();
+	fsfree(c);
+}
+
+/*
+ * check elem for illegal characters /\:*?"<>
+ * ... and relatives are also disallowed,
+ * since they specify grandparents, which we
+ * are not prepared to handle
+ */
+static int
+okelem(char *elem, int nodots)
+{
+	int c, dots;
+
+	dots = 0;
+	while((c = *(uchar*)elem) != 0){
+		if(isntfrog[c])
+			return 0;
+		if(c == '.' && dots >= 0)
+			dots++;
+		else
+			dots = -1;
+		elem++;
+	}
+	if(nodots)
+		return dots <= 0;
+	return dots <= 2;
+}
+
+static int
+cnisroot(Cname *c)
+{
+	return strcmp(c->s, "/") == 0;
+}
+
+static int
+fsisroot(Chan *c)
+{
+	return strcmp(FS(c)->name->s, "/") == 0;
+}
+
+static char*
+fspath(Cname *c, char *ext, char *path, char *spec)
+{
+	char *p, *last, *rootd;
+	int extlen = 0;
+
+	rootd = spec != nil ? spec : rootdir;
+	if(ext)
+		extlen = strlen(ext) + 1;
+	if(strlen(rootd) + extlen >= MAX_PATH)
+		error(Etoolong);
+	strcpy(path, rootd);
+	if(cnisroot(c)){
+		if(ext) {
+			strcat(path, "\\");
+			strcat(path, ext);
+		}
+	}else{
+		if(*c->s != '/') {
+			if(strlen(path) + 1 >= MAX_PATH)
+				error(Etoolong);
+			strcat(path, "\\");
+		}
+		if(strlen(path) + strlen(c->s) + extlen >= MAX_PATH)
+			error(Etoolong);
+		strcat(path, c->s);
+		if(ext){
+			strcat(path, "\\");
+			strcat(path, ext);
+		}
+	}
+	last = path;
+	for(p = path; *p != '\0'; p++){
+		if(*p == '/' || *p == '\\'){
+			*p = '\\';
+			last = p;
+		}
+	}
+	return last;
+}
+
+extern void cleancname(Cname*);
+
+static Cname *
+fswalkpath(Cname *c, char *name, int dup)
+{
+	if(dup)
+		c = newcname(c->s);
+	c = addelem(c, name);
+	if(isdotdot(name))
+		cleancname(c);
+	return c;
+}
+
+static char *
+fslastelem(Cname *c)
+{
+	char *p;
+
+	p = c->s + c->len;
+	while(p > c->s && p[-1] != '/')
+		p--;
+	return p;
+}
+
+static int
+fsdirbadentry(WIN32_FIND_DATA *data)
+{
+	wchar_t *s;
+
+	s = data->cFileName;
+	if(s[0] == 0)
+		return 1;
+	if(s[0] == '.' && (s[1] == 0 || s[1] == '.' && s[2] == 0))
+		return 1;
+
+	return 0;
+}
+
+static Fsdir*
+fsdirent(Chan *c, char *path, Fsdir *data)
+{
+	wchar_t *wpath;
+	HANDLE h;
+
+	h = ntfd2h(FS(c)->fd);
+	if(data == nil)
+		data = smalloc(sizeof(*data));
+	if(FS(c)->offset == 0){
+		if(h != INVALID_HANDLE_VALUE)
+			FindClose(h);
+		wpath = widen(path);
+		h = FindFirstFile(wpath, data);
+		free(wpath);
+		FS(c)->fd = nth2fd(h);
+		if(h == INVALID_HANDLE_VALUE){
+			free(data);
+			return nil;
+		}
+		if(!fsdirbadentry(data))
+			return data;
+	}
+	do{
+		if(!FindNextFile(h, data)){
+			free(data);
+			return nil;
+		}
+	}while(fsdirbadentry(data));
+	return data;
+}
+
+static long
+fsdirread(Chan *c, uchar *va, int count, vlong offset)
+{
+	int i, r;
+	char path[MAX_PATH], *p;
+	Fsdir *de;
+	vlong o;
+
+	if(count == 0 || offset < 0)
+		return 0;
+	p = fspath(FS(c)->name, "*.*", path, FS(c)->spec);
+	p++;
+	de = nil;
+	if(FS(c)->offset != offset){
+		de = FS(c)->de;
+		if(FS(c)->de != nil){
+			free(FS(c)->de);
+			FS(c)->de = nil;
+		}
+		FS(c)->offset = 0;
+		for(o = 0; o < offset;){
+			de = fsdirent(c, path, de);
+			if(de == nil){
+				FS(c)->offset = o;
+				return 0;
+			}
+			runestoutf(p, de->cFileName, &path[MAX_PATH]-p);
+			path[MAX_PATH-1] = '\0';
+			o += fsdirsize(de, path, c);
+		}
+		FS(c)->offset = offset;
+	}
+	for(i = 0; i < count;){
+		if(FS(c)->de != nil){	/* left over from previous read at offset */
+			de = FS(c)->de;
+			FS(c)->de = nil;
+		}else{
+			de = fsdirent(c, path, de);
+			if(de == nil)
+				break;
+		}
+		runestoutf(p, de->cFileName, &path[MAX_PATH]-p);
+		path[MAX_PATH-1] = '\0';
+		r = fsdirset(va+i, count-i, de, path, c, 1);
+		if(r <= 0){
+			/* won't fit; save for next read at this offset */
+			FS(c)->de = de;
+			break;
+		}
+		i += r;
+		FS(c)->offset += r;
+	}
+	return i;
+}
+
+static ulong
+fsqidpath(char *p)
+{
+	ulong h;
+	int c;
+
+	h = 0;
+	while(*p != '\0'){
+		/* force case insensitive file names */
+		c = *p++;
+		if(c >= 'A' && c <= 'Z')
+			c += 'a'-'A';
+		h = h * 19 ^ c;
+	}
+	return h;
+}
+
+/* TO DO: substitute fixed, made-up (unlikely) names for these */
+static char* devf[] = { "aux", "com1", "com2", "lpt1", "nul", "prn", nil };
+
+static int
+devfile(char *p)
+{
+	char *s, *t, *u, **ss;
+
+	if((u = strrchr(p, '\\')) != nil)
+		u++;
+	else if((u = strrchr(p, '/')) != nil)
+		u++;
+	else
+		u = p;
+	for(ss = devf; *ss != nil; ss++){
+		for(s = *ss, t = u; *s != '\0' && *t != '\0' && *t != '.'; s++, t++)
+			if(*s != *t && *s != *t+'a'-'A')
+				break;
+		if(*s == '\0' && (*t == '\0' || *t == '.'))
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * there are other ways to figure out
+ * the attributes and times for a file.
+ * perhaps they are faster
+ */
+static int
+fsexist(char *p, Qid *q)
+{
+	HANDLE h;
+	WIN32_FIND_DATA data;
+	wchar_t *wpath;
+
+	if(devfile(p))
+		return 0;
+	wpath = widen(p);
+	h = FindFirstFile(wpath, &data);
+	free(wpath);
+	if(h == INVALID_HANDLE_VALUE)
+		return 0;
+			if (!winfilematch(p, &data)) {
+				FindClose(h);
+				return 0;
+			}
+	FindClose(h);
+
+	q->path = fsqidpath(p);
+	q->type = 0;
+
+	if(data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+		q->type |= QTDIR;
+
+	q->vers = unixtime(data.ftLastWriteTime);
+
+	return 1;
+}
+
+static int
+fsdirset(char *edir, int n, WIN32_FIND_DATA *data, char *path, Chan *c, int isdir)
+{
+	Dir dir;
+	static char neveryone[] = "Everyone";
+
+	dir.name = narrowen(data->cFileName);
+	dir.muid = nil;
+	dir.qid.path = fsqidpath(path);
+	dir.qid.vers = 0;
+	dir.qid.type = 0;
+	dir.mode = 0;
+	dir.atime = unixtime(data->ftLastAccessTime);
+	dir.mtime = unixtime(data->ftLastWriteTime);
+	dir.qid.vers = dir.mtime;
+	dir.length = ((uvlong)data->nFileSizeHigh<<32) | ((uvlong)data->nFileSizeLow & ~((uvlong)0xFFFFFFFF<<32));
+	dir.type = 'U';
+	dir.dev = c->dev;
+
+	if(!FS(c)->usesec){
+		/* no NT security so make something up */
+		dir.uid = neveryone;
+		dir.gid = neveryone;
+		dir.mode = 0777;
+	}else if(!secstat(&dir, path, FS(c)->srv))
+		oserror();
+
+	if(data->dwFileAttributes & FILE_ATTRIBUTE_READONLY)
+		dir.mode &= ~0222;
+	if(data->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY){
+		dir.qid.type |= QTDIR;
+		dir.mode |= DMDIR;
+		dir.length = 0;
+	}
+
+	if(isdir && sizeD2M(&dir) > n)
+		n = -1;
+	else 
+		n = convD2M(&dir, edir, n);
+	if(dir.uid != neveryone)
+		free(dir.uid);
+	if(dir.gid != neveryone)
+		free(dir.gid);
+	free(dir.name);
+	return n;
+}
+
+static int
+fsdirsize(WIN32_FIND_DATA *data, char *path, Chan *c)
+{
+	int i, n;
+
+	n = widebytes(data->cFileName);
+	if(!FS(c)->usesec)
+		n += 8+8;
+	else{
+		i = secsize(path, FS(c)->srv);
+		if(i < 0)
+			oserror();
+		n += i;
+	}
+	return STATFIXLEN+n;
+}
+
+static void
+fssettime(char *path, long at, long mt)
+{
+	HANDLE h;
+	FILETIME atime, mtime;
+	wchar_t *wpath;
+
+	wpath = widen(path);
+	h = CreateFile(wpath, GENERIC_WRITE,
+		0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
+	free(wpath);
+	if(h == INVALID_HANDLE_VALUE)
+		return;
+	mtime = wintime(mt);
+	atime = wintime(at);
+	if(!SetFileTime(h, 0, &atime, &mtime)){
+		CloseHandle(h);
+		oserror();
+	}
+	CloseHandle(h);
+}
+
+static int
+fsomode(int m)
+{
+	switch(m & 0x3) {
+	case OREAD:
+	case OEXEC:
+		return GENERIC_READ;
+	case OWRITE:
+		return GENERIC_WRITE;
+	case ORDWR:
+		return GENERIC_READ|GENERIC_WRITE;
+	}
+	error(Ebadarg);
+	return 0;
+}
+
+static long
+unixtime(FILETIME ft)
+{
+	vlong t;
+
+	t = (vlong)ft.dwLowDateTime + ((vlong)ft.dwHighDateTime<<32);
+	t -= (vlong)10000000*134774*24*60*60;
+
+	return (long)(t/10000000);
+}
+
+static FILETIME
+wintime(ulong t)
+{
+	FILETIME ft;
+	vlong vt;
+
+	vt = (vlong)t*10000000+(vlong)10000000*134774*24*60*60;
+
+	ft.dwLowDateTime = vt;
+	ft.dwHighDateTime = vt>>32;
+
+	return ft;
+}
+
+/*
+ * the sec routines manage file permissions for nt.
+ * nt files have an associated security descriptor,
+ * which has in it an owner, a group,
+ * and a discretionary acces control list, or acl,
+ * which specifies the permissions for the file.
+ *
+ * the strategy for mapping between inferno owner,
+ * group, other, and mode and nt file security is:
+ *
+ *	inferno owner == nt file owner
+ *	inferno other == nt Everyone
+ *	inferno group == first non-owner,
+ *			non-Everyone user given in the acl,
+ *			or the owner if there is no such user.
+ * we examine the entire acl when check for permissions,
+ * but only report a subset.
+ *
+ * when we write an acl, we also give all permissions to
+ * the special user rootname, who is supposed to run emu in server mode.
+ */
+static void
+secinit(void)
+{
+	HMODULE lib;
+	HANDLE token;
+	TOKEN_PRIVILEGES *priv;
+	char privrock[sizeof(TOKEN_PRIVILEGES) + 1*sizeof(LUID_AND_ATTRIBUTES)];
+	SID_IDENTIFIER_AUTHORITY id = SECURITY_CREATOR_SID_AUTHORITY;
+	SID_IDENTIFIER_AUTHORITY wid = SECURITY_WORLD_SID_AUTHORITY;
+	SID_IDENTIFIER_AUTHORITY ntid = SECURITY_NT_AUTHORITY;
+
+	lib = LoadLibraryA("netapi32");
+	if(lib == 0) {
+		usesec = 0;
+		return;
+	}
+
+	net.UserGetGroups = (void*)GetProcAddress(lib, "NetUserGetGroups");
+	if(net.UserGetGroups == 0)
+		panic("bad netapi32 library");
+	net.UserGetLocalGroups = (void*)GetProcAddress(lib, "NetUserGetLocalGroups");
+	if(net.UserGetLocalGroups == 0)
+		panic("bad netapi32 library");
+	net.GetAnyDCName = (void*)GetProcAddress(lib, "NetGetAnyDCName");
+	if(net.GetAnyDCName == 0)
+		panic("bad netapi32 library");
+	net.ApiBufferFree = (void*)GetProcAddress(lib, "NetApiBufferFree");
+	if(net.ApiBufferFree == 0)
+		panic("bad netapi32 library");
+
+	if(!AllocateAndInitializeSid(&id, 1,
+		SECURITY_CREATOR_OWNER_RID,
+		1, 2, 3, 4, 5, 6, 7, &creatorowner)
+	|| !AllocateAndInitializeSid(&id, 1,
+		SECURITY_CREATOR_GROUP_RID,
+		1, 2, 3, 4, 5, 6, 7, &creatorgroup)
+	|| !AllocateAndInitializeSid(&wid, 1,
+		SECURITY_WORLD_RID,
+		1, 2, 3, 4, 5, 6, 7, &everyone)
+	|| !AllocateAndInitializeSid(&ntid, 1,
+		0,
+		1, 2, 3, 4, 5, 6, 7, &ntignore))
+		panic("can't initialize well-known sids");
+
+	fsnone = sidtouser(ntsrv, everyone);
+	if(fsnone == nil)
+		panic("can't make none user");
+
+	/*
+	 * see if we are running as the emu server user
+	 * if so, set up SE_RESTORE_NAME privilege,
+	 * which allows setting the owner field in a security descriptor.
+	 * other interesting privileges are SE_TAKE_OWNERSHIP_NAME,
+	 * which enables changing the ownership of a file to yourself
+	 * regardless of the permissions on the file, SE_BACKUP_NAME,
+	 * which enables reading any files regardless of permission,
+	 * and SE_CHANGE_NOTIFY_NAME, which enables walking through
+	 * directories without X permission.
+	 * SE_RESTORE_NAME and SE_BACKUP_NAME together allow writing
+	 * and reading any file data, regardless of permission,
+	 * if the file is opened with FILE_BACKUP_SEMANTICS.
+	 */
+	isserver = 0;
+	fsuser = secuser();
+	if(fsuser == nil)
+		fsuser = fsnone;
+	else if(runescmp(fsuser->name, rootname) == 0
+	     && OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES, &token)){
+		priv = (TOKEN_PRIVILEGES*)privrock;
+		priv->PrivilegeCount = 1;
+		priv->Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
+		if(LookupPrivilegeValue(NULL, SE_RESTORE_NAME, &priv->Privileges[0].Luid)
+		&& AdjustTokenPrivileges(token, 0, priv, 0, NULL, NULL))
+			isserver = 1;
+		CloseHandle(token);
+	}
+}
+
+/*
+ * get the User for the executing process
+ */
+static User*
+secuser(void)
+{
+	DWORD need;
+	HANDLE token;
+	TOKEN_USER *tu;
+	char turock[sizeof(TOKEN_USER) + MAX_SID];
+
+	if(!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &token))
+		return nil;
+
+	tu = (TOKEN_USER*)turock;
+	if(!GetTokenInformation(token, TokenUser, tu, sizeof(turock), &need)){
+		CloseHandle(token);
+		return nil;
+	}
+	CloseHandle(token);
+	return sidtouser(nil, tu->User.Sid);
+}
+
+static int
+secstat(Dir *dir, char *file, Rune *srv)
+{
+	int ok, n;
+	Stat st;
+	char sdrock[SD_ROCK];
+	SECURITY_DESCRIPTOR *sd;
+
+	sd = secsd(file, sdrock);
+	if(sd == nil){
+		int e = GetLastError();
+		if(e == ERROR_ACCESS_DENIED || e == ERROR_SHARING_VIOLATION){
+			dir->uid = strdup("unknown");
+			dir->gid = strdup("unknown");
+			if(dir->uid == nil || dir->gid == nil){
+				free(dir->uid);
+				error(Enomem);	/* will change to use kstrdup */
+			}
+			dir->mode = 0;
+			return 1;
+		}
+		return 0;
+	}
+	ok = secsdstat(sd, &st, srv);
+	if(sd != (void*)sdrock)
+		free(sd);
+	if(ok){
+		dir->mode = st.mode;
+		n = runenlen(st.owner->name, runeslen(st.owner->name));
+		dir->uid = smalloc(n+1);
+		runestoutf(dir->uid, st.owner->name, n+1);
+		n = runenlen(st.group->name, runeslen(st.group->name));
+		dir->gid = smalloc(n+1);
+		runestoutf(dir->gid, st.group->name, n+1);
+	}
+	return ok;
+}
+
+static int
+secsize(char *file, Rune *srv)
+{
+	int ok;
+	Stat st;
+	char sdrock[SD_ROCK];
+	SECURITY_DESCRIPTOR *sd;
+
+	sd = secsd(file, sdrock);
+	if(sd == nil){
+		int e = GetLastError();
+		if(e == ERROR_ACCESS_DENIED || e == ERROR_SHARING_VIOLATION)
+			return 7+7;
+		return -1;
+	}
+	ok = secsdstat(sd, &st, srv);
+	if(sd != (void*)sdrock)
+		free(sd);
+	if(ok)
+		return runenlen(st.owner->name, runeslen(st.owner->name))+runenlen(st.group->name, runeslen(st.group->name));
+	return -1;
+}
+
+/*
+ * verify that u had access to file
+ */
+static void
+seccheck(char *file, ulong access, Rune *srv)
+{
+	if(!sechasperm(file, access, srv))
+		error(Eperm);
+}
+
+static int
+sechasperm(char *file, ulong access, Rune *srv)
+{
+	int ok;
+	char sdrock[SD_ROCK];
+	SECURITY_DESCRIPTOR *sd;
+
+	/*
+	 * only really needs dacl info
+	 */
+	sd = secsd(file, sdrock);
+	if(sd == nil)
+		return 0;
+	ok = secsdhasperm(sd, access, srv);
+	if(sd != (void*)sdrock)
+		free(sd);
+	return ok;
+}
+
+static SECURITY_DESCRIPTOR*
+secsd(char *file, char sdrock[SD_ROCK])
+{
+	DWORD need;
+	SECURITY_DESCRIPTOR *sd;
+	char *path, pathrock[6];
+	wchar_t *wpath;
+
+	path = file;
+	if(path[0] != '\0' && path[1] == ':' && path[2] == '\0'){
+		path = pathrock;
+		strcpy(path, "?:\\.");
+		path[0] = file[0];
+	}
+	sd = (SECURITY_DESCRIPTOR*)sdrock;
+	need = 0;
+	wpath = widen(path);
+	if(GetFileSecurity(wpath, OWNER_SECURITY_INFORMATION|DACL_SECURITY_INFORMATION, sd, SD_ROCK, &need)) {
+		free(wpath);
+		return sd;
+	}
+	 if(GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
+		free(wpath);
+		return nil;
+	}
+	sd = malloc(need);
+	if(sd == nil) {
+		free(wpath);
+		error(Enomem);
+	}
+	if(GetFileSecurity(wpath, OWNER_SECURITY_INFORMATION|DACL_SECURITY_INFORMATION, sd, need, &need)) {
+		free(wpath);
+		return sd;
+	}
+	free(wpath);
+	free(sd);
+	return nil;
+}
+
+static int
+secsdstat(SECURITY_DESCRIPTOR *sd, Stat *st, Rune *srv)
+{
+	ACL *acl;
+	BOOL hasacl, b;
+	ACE_HEADER *aceh;
+	User *owner, *group;
+	SID *sid, *osid, *gsid;
+	ACCESS_ALLOWED_ACE *ace;
+	int i, allow, deny, *p, m;
+	ACL_SIZE_INFORMATION size;
+
+	st->mode = 0;
+
+	osid = nil;
+	gsid = nil;
+	if(!GetSecurityDescriptorOwner(sd, &osid, &b)
+	|| !GetSecurityDescriptorDacl(sd, &hasacl, &acl, &b))
+		return 0;
+
+	if(acl == 0)
+		size.AceCount = 0;
+	else if(!GetAclInformation(acl, &size, sizeof(size), AclSizeInformation))
+		return 0;
+
+	/*
+	 * first pass through acl finds group
+	 */
+	for(i = 0; i < size.AceCount; i++){
+		if(!GetAce(acl, i, &aceh))
+			continue;
+		if(aceh->AceFlags & INHERIT_ONLY_ACE)
+			continue;
+
+		if(aceh->AceType != ACCESS_ALLOWED_ACE_TYPE
+		&& aceh->AceType != ACCESS_DENIED_ACE_TYPE)
+			continue;
+
+		ace = (ACCESS_ALLOWED_ACE*)aceh;
+		sid = (SID*)&ace->SidStart;
+		if(EqualSid(sid, creatorowner) || EqualSid(sid, creatorgroup))
+			continue;
+
+		if(EqualSid(sid, everyone))
+			;
+		else if(EqualSid(sid, osid))
+			;
+		else if(EqualPrefixSid(sid, ntignore))
+			continue;		/* boring nt accounts */
+		else{
+			gsid = sid;
+			break;
+		}
+	}
+	if(gsid == nil)
+		gsid = osid;
+
+	owner = sidtouser(srv, osid);
+	if(owner == nil)
+		return 0;
+	group = sidtouser(srv, gsid);
+	if(group == nil)
+		return 0;
+
+	/* no acl means full access */
+	allow = 0;
+	if(acl == 0)
+		allow = 0777;
+	deny = 0;
+	for(i = 0; i < size.AceCount; i++){
+		if(!GetAce(acl, i, &aceh))
+			continue;
+		if(aceh->AceFlags & INHERIT_ONLY_ACE)
+			continue;
+
+		if(aceh->AceType == ACCESS_ALLOWED_ACE_TYPE)
+			p = &allow;
+		else if(aceh->AceType == ACCESS_DENIED_ACE_TYPE)
+			p = &deny;
+		else
+			continue;
+
+		ace = (ACCESS_ALLOWED_ACE*)aceh;
+		sid = (SID*)&ace->SidStart;
+		if(EqualSid(sid, creatorowner) || EqualSid(sid, creatorgroup))
+			continue;
+
+		m = 0;
+		if(ace->Mask & FILE_EXECUTE)
+			m |= 1;
+		if(ace->Mask & FILE_WRITE_DATA)
+			m |= 2;
+		if(ace->Mask & FILE_READ_DATA)
+			m |= 4;
+
+		if(ismembersid(srv, owner, sid))
+			*p |= (m << 6) & ~(allow|deny) & 0700;
+		if(ismembersid(srv, group, sid))
+			*p |= (m << 3) & ~(allow|deny) & 0070;
+		if(EqualSid(everyone, sid))
+			*p |= m & ~(allow|deny) & 0007;
+	}
+
+	st->mode = allow & ~deny;
+	st->owner = owner;
+	st->group = group;
+	return 1;
+}
+
+static int
+secsdhasperm(SECURITY_DESCRIPTOR *sd, ulong access, Rune *srv)
+{
+	User *u;
+	ACL *acl;
+	BOOL hasacl, b;
+	ACE_HEADER *aceh;
+	SID *sid, *osid, *gsid;
+	int i, allow, deny, *p, m;
+	ACCESS_ALLOWED_ACE *ace;
+	ACL_SIZE_INFORMATION size;
+
+	u = up->env->ui;
+	allow = 0;
+	deny = 0;
+	osid = nil;
+	gsid = nil;
+	if(!GetSecurityDescriptorDacl(sd, &hasacl, &acl, &b))
+		return 0;
+
+	/* no acl means full access */
+	if(acl == 0)
+		return 1;
+	if(!GetAclInformation(acl, &size, sizeof(size), AclSizeInformation))
+		return 0;
+	for(i = 0; i < size.AceCount; i++){
+		if(!GetAce(acl, i, &aceh))
+			continue;
+		if(aceh->AceFlags & INHERIT_ONLY_ACE)
+			continue;
+
+		if(aceh->AceType == ACCESS_ALLOWED_ACE_TYPE)
+			p = &allow;
+		else if(aceh->AceType == ACCESS_DENIED_ACE_TYPE)
+			p = &deny;
+		else
+			continue;
+
+		ace = (ACCESS_ALLOWED_ACE*)aceh;
+		sid = (SID*)&ace->SidStart;
+		if(EqualSid(sid, creatorowner) || EqualSid(sid, creatorgroup))
+			continue;
+
+		m = ace->Mask;
+
+		if(ismembersid(srv, u, sid))
+			*p |= m & ~(allow|deny);
+	}
+
+	allow &= ~deny;
+
+	return (allow & access) == access;
+}
+
+static SECURITY_DESCRIPTOR*
+secmksd(char *sdrock, Stat *st, ACL *dacl, int isdir)
+{
+	int m;
+
+	ulong mode;
+	ACE_HEADER *aceh;
+	SECURITY_DESCRIPTOR *sd;
+
+	sd = (SECURITY_DESCRIPTOR*)sdrock;
+	if(!InitializeAcl(dacl, ACL_ROCK, ACL_REVISION))
+		return nil;
+
+	mode = st->mode;
+	if(st->owner == st->group){
+		mode |= (mode >> 3) & 0070;
+		mode |= (mode << 3) & 0700;
+	}
+
+
+	m = modetomask[(mode>>6) & 7];
+	if(!AddAccessAllowedAce(dacl, ACL_REVISION, m, st->owner->sid))
+		return nil;
+
+	if(isdir && !AddAccessAllowedAce(dacl, ACL_REVISION, m, creatorowner))
+		return nil;
+
+	m = modetomask[(mode>>3) & 7];
+	if(!AddAccessAllowedAce(dacl, ACL_REVISION, m, st->group->sid))
+		return nil;
+
+	m = modetomask[(mode>>0) & 7];
+	if(!AddAccessAllowedAce(dacl, ACL_REVISION, m, everyone))
+		return nil;
+
+	if(isdir){
+		/* hack to add inherit flags */
+		if(!GetAce(dacl, 1, &aceh))
+			return nil;
+		aceh->AceFlags |= OBJECT_INHERIT_ACE|CONTAINER_INHERIT_ACE;
+		if(!GetAce(dacl, 2, &aceh))
+			return nil;
+		aceh->AceFlags |= OBJECT_INHERIT_ACE|CONTAINER_INHERIT_ACE;
+		if(!GetAce(dacl, 3, &aceh))
+			return nil;
+		aceh->AceFlags |= OBJECT_INHERIT_ACE|CONTAINER_INHERIT_ACE;
+	}
+
+	/*
+	 * allow server user to access any file
+	 */
+	if(isserver){
+		if(!AddAccessAllowedAce(dacl, ACL_REVISION, RMODE|WMODE|XMODE, fsuser->sid))
+			return nil;
+		if(isdir){
+			if(!GetAce(dacl, 4, &aceh))
+				return nil;
+			aceh->AceFlags |= OBJECT_INHERIT_ACE|CONTAINER_INHERIT_ACE;
+		}
+	}
+
+	if(!InitializeSecurityDescriptor(sd, SECURITY_DESCRIPTOR_REVISION))
+		return nil;
+	if(!SetSecurityDescriptorDacl(sd, 1, dacl, 0))
+		return nil;
+//	if(isserver && !SetSecurityDescriptorOwner(sd, st->owner->sid, 0))
+//		return nil;
+	return sd;
+}
+
+/*
+ * the user manipulation routines
+ * just make it easier to deal with user identities
+ */
+static User*
+sidtouser(Rune *srv, SID *s)
+{
+	SID_NAME_USE type;
+	Rune aname[100], dname[100];
+	DWORD naname, ndname;
+	User *u;
+
+	qlock(&users.lk);
+	for(u = users.u; u != 0; u = u->next)
+		if(EqualSid(s, u->sid))
+			break;
+	qunlock(&users.lk);
+
+	if(u != 0)
+		return u;
+
+	naname = sizeof(aname);
+	ndname = sizeof(dname);
+
+	if(!LookupAccountSidW(srv, s, aname, &naname, dname, &ndname, &type))
+		return mkuser(s, SidTypeUnknown, L"unknown", L"unknown");
+	return mkuser(s, type, aname, dname);
+}
+
+static User*
+domnametouser(Rune *srv, Rune *name, Rune *dom)
+{
+	User *u;
+
+	qlock(&users.lk);
+	for(u = users.u; u != 0; u = u->next)
+		if(runescmp(name, u->name) == 0 && runescmp(dom, u->dom) == 0)
+			break;
+	qunlock(&users.lk);
+	if(u == 0)
+		u = nametouser(srv, name);
+	return u;
+}
+
+static User*
+nametouser(Rune *srv, Rune *name)
+{
+	char sidrock[MAX_SID];
+	SID *sid;
+	SID_NAME_USE type;
+	Rune dom[MAX_PATH];
+	DWORD nsid, ndom;
+
+	sid = (SID*)sidrock;
+	nsid = sizeof(sidrock);
+	ndom = sizeof(dom);
+	if(!LookupAccountNameW(srv, name, sid, &nsid, dom, &ndom, &type))
+		return nil;
+
+	return mkuser(sid, type, name, dom);
+}
+
+/*
+ * this mapping could be cached
+ */
+static User*
+unametouser(Rune *srv, char *name)
+{
+	Rune rname[MAX_PATH];
+
+	utftorunes(rname, name, MAX_PATH);
+	return nametouser(srv, rname);
+}
+
+/*
+ * make a user structure and add it to the global cache.
+ */
+static User*
+mkuser(SID *sid, int type, Rune *name, Rune *dom)
+{
+	User *u;
+
+	qlock(&users.lk);
+	for(u = users.u; u != 0; u = u->next){
+		if(EqualSid(sid, u->sid)){
+			qunlock(&users.lk);
+			return u;
+		}
+	}
+
+	switch(type) {
+	default:
+		break;
+	case SidTypeDeletedAccount:
+		name = L"deleted";
+		break;
+	case SidTypeInvalid:
+		name = L"invalid";
+		break;
+	case SidTypeUnknown:
+		name = L"unknown";
+		break;
+	}
+
+	u = malloc(sizeof(User));
+	if(u == nil){
+		qunlock(&users.lk);
+		return 0;
+	}
+	u->next = nil;
+	u->group = nil;
+	u->sid = dupsid(sid);
+	u->type = type;
+	u->name = nil;
+	if(name != nil)
+		u->name = runesdup(name);
+	u->dom = nil;
+	if(dom != nil)
+		u->dom = runesdup(dom);
+
+	u->next = users.u;
+	users.u = u;
+
+	qunlock(&users.lk);
+	return u;
+}
+
+/*
+ * check if u is a member of gsid,
+ * which might be a group.
+ */
+static int
+ismembersid(Rune *srv, User *u, SID *gsid)
+{
+	User *g;
+
+	if(EqualSid(u->sid, gsid))
+		return 1;
+
+	g = sidtouser(srv, gsid);
+	if(g == 0)
+		return 0;
+	return ismember(u, g);
+}
+
+static int
+ismember(User *u, User *g)
+{
+	Gmem *grps;
+
+	if(EqualSid(u->sid, g->sid))
+		return 1;
+
+	if(EqualSid(g->sid, everyone))
+		return 1;
+
+	qlock(&u->lk);
+	addgroups(u, 0);
+	for(grps = u->group; grps != 0; grps = grps->next){
+		if(EqualSid(grps->user->sid, g->sid)){
+			qunlock(&u->lk);
+			return 1;
+		}
+	}
+	qunlock(&u->lk);
+	return 0;
+}
+
+/*
+ * find out what groups a user belongs to.
+ * if force, throw out the old info and do it again.
+ *
+ * note that a global group is also know as a group,
+ * and a local group is also know as an alias.
+ * global groups can only contain users.
+ * local groups can contain global groups or users.
+ * this code finds all global groups to which a user belongs,
+ * and all the local groups to which the user or a global group
+ * containing the user belongs.
+ */
+static void
+addgroups(User *u, int force)
+{
+	LOCALGROUP_USERS_INFO_0 *loc;
+	GROUP_USERS_INFO_0 *grp;
+	DWORD i, n, rem;
+	User *gu;
+	Gmem *g, *next;
+	Rune *srv, srvrock[MAX_PATH];
+
+	if(force){
+		u->gotgroup = 0;
+		for(g = u->group; g != nil; g = next){
+			next = g->next;
+			free(g);
+		}
+		u->group = nil;
+	}
+	if(u->gotgroup)
+		return;
+	u->gotgroup = 1;
+
+	n = 0;
+	srv = domsrv(u->dom, srvrock);
+	i = net.UserGetGroups(srv, u->name, 0,
+		(BYTE**)&grp, MAX_PREFERRED_LENGTH, &n, &rem);
+	if(i == NERR_Success || i == ERROR_MORE_DATA){
+		for(i = 0; i < n; i++){
+			gu = domnametouser(srv, grp[i].grui0_name, u->dom);
+			if(gu == 0)
+				continue;
+			g = malloc(sizeof(Gmem));
+			if(g == nil)
+				error(Enomem);
+			g->user = gu;
+			g->next = u->group;
+			u->group = g;
+		}
+		net.ApiBufferFree(grp);
+	}
+
+	n = 0;
+	i = net.UserGetLocalGroups(srv, u->name, 0, LG_INCLUDE_INDIRECT,
+		(BYTE**)&loc, MAX_PREFERRED_LENGTH, &n, &rem);
+	if(i == NERR_Success || i == ERROR_MORE_DATA){
+		for(i = 0; i < n; i++){
+			gu = domnametouser(srv, loc[i].lgrui0_name, u->dom);
+			if(gu == NULL)
+				continue;
+			g = malloc(sizeof(Gmem));
+			if(g == nil)
+				error(Enomem);
+			g->user = gu;
+			g->next = u->group;
+			u->group = g;
+		}
+		net.ApiBufferFree(loc);
+	}
+}
+
+static SID*
+dupsid(SID *sid)
+{
+	SID *nsid;
+	int n;
+
+	n = GetLengthSid(sid);
+	nsid = malloc(n);
+	if(nsid == nil || !CopySid(n, nsid, sid))
+		panic("can't copy sid");
+	return nsid;
+}
+
+/*
+ * return the name of the server machine for file
+ */
+static Rune*
+filesrv(char *file)
+{
+	int n;
+	Rune *srv;
+	char *p, uni[MAX_PATH], mfile[MAX_PATH];
+	wchar_t vol[3];
+
+	strcpy(mfile, file);
+	/* assume file is a fully qualified name - X: or \\server */
+	if(file[1] == ':') {
+		vol[0] = file[0];
+		vol[1] = file[1];
+		vol[2] = 0;
+		if(GetDriveType(vol) != DRIVE_REMOTE)
+			return 0;
+		n = sizeof(uni);
+		if(WNetGetUniversalName(vol, UNIVERSAL_NAME_INFO_LEVEL, uni, &n) != NO_ERROR)
+			return nil;
+		runestoutf(mfile, ((UNIVERSAL_NAME_INFO*)uni)->lpUniversalName, MAX_PATH);
+		file = mfile;
+	}
+	file += 2;
+	p = strchr(file, '\\');
+	if(p == 0)
+		n = strlen(file);
+	else
+		n = p - file;
+	if(n >= MAX_PATH)
+		n = MAX_PATH-1;
+
+	memmove(uni, file, n);
+	uni[n] = '\0';
+
+	srv = malloc((n + 1) * sizeof(Rune));
+	if(srv == nil)
+		panic("filesrv: no memory");
+	utftorunes(srv, uni, n+1);
+	return srv;
+}
+
+/*
+ * does the file system support acls?
+ */
+static int
+fsacls(char *file)
+{
+	char *p;
+	DWORD flags;
+	char path[MAX_PATH];
+	wchar_t wpath[MAX_PATH];
+
+	/* assume file is a fully qualified name - X: or \\server */
+	if(file[1] == ':') {
+		path[0] = file[0];
+		path[1] = file[1];
+		path[2] = '\\';
+		path[3] = 0;
+	} else {
+		strcpy(path, file);
+		p = strchr(path+2, '\\');
+		if(p == 0)
+			return 0;
+		p = strchr(p+1, '\\');
+		if(p == 0)
+			strcat(path, "\\");
+		else
+			p[1] = 0;
+	}
+	utftorunes(wpath, path, MAX_PATH);
+	if(!GetVolumeInformation(wpath, NULL, 0, NULL, NULL, &flags, NULL, 0))
+		return 0;
+
+	return flags & FS_PERSISTENT_ACLS;
+}
+
+/*
+ * given a domain, find out the server to ask about its users.
+ * we just ask the local machine to do the translation,
+ * so it might fail sometimes.  in those cases, we don't
+ * trust the domain anyway, and vice versa, so it's not
+ * clear what benifit we would gain by getting the answer "right".
+ */
+static Rune*
+domsrv(Rune *dom, Rune srv[MAX_PATH])
+{
+	Rune *psrv;
+	int n, r;
+
+	if(dom[0] == 0)
+		return nil;
+
+	r = net.GetAnyDCName(NULL, dom, (LPBYTE*)&psrv);
+	if(r == NERR_Success) {
+		n = runeslen(psrv);
+		if(n >= MAX_PATH)
+			n = MAX_PATH-1;
+		memmove(srv, psrv, n*sizeof(Rune));
+		srv[n] = 0;
+		net.ApiBufferFree(psrv);
+		return srv;
+	}
+
+	return nil;
+}
+
+Rune*
+runesdup(Rune *r)
+{
+	int n;
+	Rune *s;
+
+	n = runeslen(r) + 1;
+	s = malloc(n * sizeof(Rune));
+	if(s == nil)
+		error(Enomem);
+	memmove(s, r, n * sizeof(Rune));
+	return s;
+}
+
+int
+runeslen(Rune *r)
+{
+	int n;
+
+	n = 0;
+	while(*r++ != 0)
+		n++;
+	return n;
+}
+
+char*
+runestoutf(char *p, Rune *r, int nc)
+{
+	char *op, *ep;
+	int n, c;
+
+	op = p;
+	ep = p + nc;
+	while(c = *r++) {
+		n = 1;
+		if(c >= Runeself)
+			n = runelen(c);
+		if(p + n >= ep)
+			break;
+		if(c < Runeself)
+			*p++ = c;
+		else
+			p += runetochar(p, r-1);
+	}
+	*p = '\0';
+	return op;
+}
+
+Rune*
+utftorunes(Rune *r, char *p, int nc)
+{
+	Rune *or, *er;
+
+	or = r;
+	er = r + nc;
+	while(*p != '\0' && r + 1 < er)
+		p += chartorune(r++, p);
+	*r = '\0';
+	return or;
+}
+
+int
+runescmp(Rune *s1, Rune *s2)
+{
+	Rune r1, r2;
+
+	for(;;) {
+		r1 = *s1++;
+		r2 = *s2++;
+		if(r1 != r2) {
+			if(r1 > r2)
+				return 1;
+			return -1;
+		}
+		if(r1 == 0)
+			return 0;
+	}
+}
+
+Dev fsdevtab = {
+	'U',
+	"fs",
+
+	fsinit,
+	fsattach,
+	fswalk,
+	fsstat,
+	fsopen,
+	fscreate,
+	fsclose,
+	fsread,
+	devbread,
+	fswrite,
+	devbwrite,
+	fsremove,
+	fswstat
+};