diff --git a/include/libc.h b/include/libc.h
index 2eceaea9cb..7b86399fee 100644
--- a/include/libc.h
+++ b/include/libc.h
@@ -137,12 +137,9 @@ extern	void	sysfatal(char*, ...);
 #define	ORDWR	2	/* read and write */
 #define	OEXEC	3	/* execute, == read but check execute permission */
 #define	OTRUNC	16	/* or'ed in (except for exec), truncate file first */
-#define	OCEXEC	32	/* or'ed in, close on exec */
 #define	ORCLOSE	64	/* or'ed in, remove on close */
 #define	ODIRECT	128	/* or'ed in, direct access */
-#define	ONONBLOCK 256	/* or'ed in, non-blocking call */
 #define	OEXCL	0x1000	/* or'ed in, exclusive use (create only) */
-#define	OLOCK	0x2000	/* or'ed in, lock after opening */
 #define	OAPPEND	0x4000	/* or'ed in, append only */
 
 #define	AEXIST	0	/* accessible: exists */
@@ -279,7 +276,6 @@ extern	int	notifyon(char*);
 extern	int	notifyoff(char*);
 extern	int	p9open(char*, int);
 extern	int	fd2path(int, char*, int);
-extern	int	p9pipe(int*);
 extern	long	readn(int, void*, long);
 extern	int	remove(const char*);
 extern	vlong	p9seek(int, vlong, int);
@@ -290,6 +286,18 @@ extern	Waitmsg*	waitnohang(void);
 extern	int	p9waitpid(void);
 extern	ulong	rendezvous(ulong, ulong);
 
+#ifdef __MINGW32__
+extern int fork();
+extern int pread(int fd, void *buf, int n, int off);
+extern int pwrite(int fd, void *buf, int n, int off);
+#define execvp(prog, argv) execvp(prog, (const char**)(argv))
+#define lseek(fd, n, base) _lseeki64(fd, n, base)
+#define mkdir(path, perm) mkdir(path)
+#define pipe(fd) _pipe(fd, 512, O_BINARY)
+#else
+#define O_BINARY 0
+#endif
+
 #ifndef NOPLAN9DEFINES
 #define alarm		p9alarm
 #define	dup		p9dup
@@ -303,7 +311,6 @@ extern	ulong	rendezvous(ulong, ulong);
 #define create		p9create
 #undef open
 #define open		p9open
-#define pipe		p9pipe
 #define	waitfor		p9waitfor
 #endif
 
diff --git a/include/u.h b/include/u.h
index 1b196286eb..6dd55a09c7 100644
--- a/include/u.h
+++ b/include/u.h
@@ -77,6 +77,9 @@ extern "C" {
 #define _NEEDUINT 1
 #define _NEEDULONG 1
 
+#ifdef __MINGW32__
+typedef jmp_buf sigjmp_buf;
+#endif
 typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 
 #if defined(__linux__)
@@ -135,6 +138,7 @@ typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 #	undef _NEEDUSHORT
 #	undef _NEEDUINT
 #	undef _NEEDULONG
+#elif defined(__MINGW32__)
 #else
 	/* No idea what system this is -- try some defaults */
 #	include <pthread.h>
@@ -199,7 +203,7 @@ typedef u64int uint64;
  */
 #if defined(__GNUC__)
 #	undef strcmp	/* causes way too many warnings */
-#	if __GNUC__ >= 4 || (__GNUC__==3 && !defined(__APPLE_CC__))
+#	if __GNUC__ >= 4 || (__GNUC__==3 && !defined(__APPLE_CC__) && !defined(__MINGW32__))
 #		undef AUTOLIB
 #		define AUTOLIB(x) int __p9l_autolib_ ## x __attribute__ ((weak));
 #		undef AUTOFRAMEWORK
diff --git a/lib/codereview/codereview.py b/lib/codereview/codereview.py
index 0be956b614..0d97226b76 100644
--- a/lib/codereview/codereview.py
+++ b/lib/codereview/codereview.py
@@ -403,7 +403,7 @@ def LoadAllCL(ui, repo, web=True):
 # Find repository root.  On error, ui.warn and return None
 def RepoDir(ui, repo):
 	url = repo.url();
-	if not url.startswith('file:/'):
+	if not url.startswith('file:'):
 		ui.warn("repository %s is not in local file system\n" % (url,))
 		return None
 	url = url[5:]
diff --git a/src/lib9/Makefile b/src/lib9/Makefile
index 6f0739d2ce..9038730b1f 100644
--- a/src/lib9/Makefile
+++ b/src/lib9/Makefile
@@ -54,7 +54,6 @@ LIB9OFILES=\
 	_exits.$O\
 	argv0.$O\
 	atoi.$O\
-	await.$O\
 	cleanname.$O\
 	create.$O\
 	dirfstat.$O\
@@ -69,23 +68,32 @@ LIB9OFILES=\
 	exits.$O\
 	getenv.$O\
 	getfields.$O\
-	getuser.$O\
 	getwd.$O\
-	jmp.$O\
 	main.$O\
 	nan.$O\
-	notify.$O\
 	nulldir.$O\
 	open.$O\
-	pipe.$O\
 	readn.$O\
-	rfork.$O\
 	seek.$O\
 	strecpy.$O\
 	sysfatal.$O\
 	time.$O\
 	tokenize.$O\
 
+ifeq ($(GOOS),mingw)
+LIB9OFILES+=\
+	win32.$O\
+
+else
+LIB9OFILES+=\
+	await.$O\
+	getuser.$O\
+	jmp.$O\
+	notify.$O\
+	rfork.$O\
+
+endif
+
 OFILES=\
 	$(LIB9OFILES)\
 	$(FMTOFILES)\
diff --git a/src/lib9/_p9dir.c b/src/lib9/_p9dir.c
index ededa0a92e..58c0822a4d 100644
--- a/src/lib9/_p9dir.c
+++ b/src/lib9/_p9dir.c
@@ -29,20 +29,6 @@ THE SOFTWARE.
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <dirent.h>
-#include <pwd.h>
-#include <grp.h>
-
-/*
- * No need for a real disk size function here:
- * the Go build isn't looking at raw disk devices,
- * so this avoids portability problems.
- */
-#define  _HAVEDISKSIZE
-static vlong
-disksize(int fd, int x)
-{
-	return 0;
-}
 
 /*
  * Caching the last group and passwd looked up is
@@ -55,9 +41,6 @@ _p9dir(struct stat *lst, struct stat *st, char *name, Dir *d, char **str, char *
 {
 	char *s;
 	char tmp[20];
-	static struct group *g;
-	static struct passwd *p;
-	static int gid, uid;
 	int sz, fd;
 
 	fd = -1;
@@ -88,11 +71,8 @@ _p9dir(struct stat *lst, struct stat *st, char *name, Dir *d, char **str, char *
 	sz += strlen(s)+1;
 
 	/* user */
-	if(p == nil || st->st_uid != uid || p->pw_uid != uid){
-		snprint(tmp, sizeof tmp, "%d", (int)st->st_uid);
-		s = tmp;
-	}else
-		s = p->pw_name;
+	snprint(tmp, sizeof tmp, "%d", (int)st->st_uid);
+	s = tmp;
 	sz += strlen(s)+1;
 	if(d){
 		if(*str+strlen(s)+1 > estr)
@@ -105,11 +85,8 @@ _p9dir(struct stat *lst, struct stat *st, char *name, Dir *d, char **str, char *
 	}
 
 	/* group */
-	if(g == nil || st->st_gid != gid || g->gr_gid != gid){
-		snprint(tmp, sizeof tmp, "%d", (int)st->st_gid);
-		s = tmp;
-	}else
-		s = g->gr_name;
+	snprint(tmp, sizeof tmp, "%d", (int)st->st_gid);
+	s = tmp;
 	sz += strlen(s)+1;
 	if(d){
 		if(*str + strlen(s)+1 > estr)
@@ -141,12 +118,16 @@ _p9dir(struct stat *lst, struct stat *st, char *name, Dir *d, char **str, char *
 			d->mode |= DMDIR;
 			d->qid.type = QTDIR;
 		}
+#ifdef S_ISLNK
 		if(S_ISLNK(lst->st_mode))	/* yes, lst not st */
 			d->mode |= DMSYMLINK;
+#endif
 		if(S_ISFIFO(st->st_mode))
 			d->mode |= DMNAMEDPIPE;
+#ifdef S_ISSOCK
 		if(S_ISSOCK(st->st_mode))
 			d->mode |= DMSOCKET;
+#endif
 		if(S_ISBLK(st->st_mode)){
 			d->mode |= DMDEVICE;
 			d->qid.path = ('b'<<16)|st->st_rdev;
@@ -156,12 +137,10 @@ _p9dir(struct stat *lst, struct stat *st, char *name, Dir *d, char **str, char *
 			d->qid.path = ('c'<<16)|st->st_rdev;
 		}
 		/* fetch real size for disks */
-#ifdef _HAVEDISKSIZE
 		if(S_ISBLK(st->st_mode) && (fd = open(name, O_RDONLY)) >= 0){
-			d->length = disksize(fd, major(st->st_dev));
+			d->length = 0;
 			close(fd);
 		}
-#endif
 #if defined(DIOCGMEDIASIZE)
 		if(isdisk(st)){
 			int fd;
diff --git a/src/lib9/create.c b/src/lib9/create.c
index 8e5cbc360c..59845ba91f 100644
--- a/src/lib9/create.c
+++ b/src/lib9/create.c
@@ -37,14 +37,11 @@ THE SOFTWARE.
 int
 p9create(char *path, int mode, ulong perm)
 {
-	int fd, cexec, umode, rclose, lock, rdwr;
-	struct flock fl;
+	int fd, umode, rclose, rdwr;
 
 	rdwr = mode&3;
-	lock = mode&OLOCK;
-	cexec = mode&OCEXEC;
 	rclose = mode&ORCLOSE;
-	mode &= ~(ORCLOSE|OCEXEC|OLOCK);
+	mode &= ~ORCLOSE;
 
 	/* XXX should get mode mask right? */
 	fd = -1;
@@ -75,23 +72,11 @@ p9create(char *path, int mode, ulong perm)
 			werrstr("unsupported mode in create");
 			goto out;
 		}
+		umode |= O_BINARY;
 		fd = open(path, umode, perm);
 	}
 out:
 	if(fd >= 0){
-		if(lock){
-			fl.l_type = (rdwr==OREAD) ? F_RDLCK : F_WRLCK;
-			fl.l_whence = SEEK_SET;
-			fl.l_start = 0;
-			fl.l_len = 0;
-			if(fcntl(fd, F_SETLK, &fl) < 0){
-				close(fd);
-				werrstr("lock: %r");
-				return -1;
-			}
-		}
-		if(cexec)
-			fcntl(fd, F_SETFL, FD_CLOEXEC);
 		if(rclose)
 			remove(path);
 	}
diff --git a/src/lib9/dirfwstat.c b/src/lib9/dirfwstat.c
index 657a98df03..15f1c12520 100644
--- a/src/lib9/dirfwstat.c
+++ b/src/lib9/dirfwstat.c
@@ -61,10 +61,12 @@ dirfwstat(int fd, Dir *dir)
 	struct timeval tv[2];
 
 	ret = 0;
+#ifndef __MINGW32__
 	if(~dir->mode != 0){
 		if(fchmod(fd, dir->mode) < 0)
 			ret = -1;
 	}
+#endif
 	if(~dir->mtime != 0){
 		tv[0].tv_sec = dir->mtime;
 		tv[0].tv_usec = 0;
diff --git a/src/lib9/dirstat.c b/src/lib9/dirstat.c
index 5cb6790bcf..6c476753b0 100644
--- a/src/lib9/dirstat.c
+++ b/src/lib9/dirstat.c
@@ -39,11 +39,17 @@ dirstat(char *file)
 	Dir *d;
 	char *str;
 
+#ifdef __MINGW32__
+	if(stat(file, &st) < 0)
+		return nil;
+	lst = st;
+#else
 	if(lstat(file, &lst) < 0)
 		return nil;
 	st = lst;
 	if((lst.st_mode&S_IFMT) == S_IFLNK)
 		stat(file, &st);
+#endif
 
 	nstr = _p9dir(&lst, &st, file, nil, nil, nil);
 	d = malloc(sizeof(Dir)+nstr);
diff --git a/src/lib9/open.c b/src/lib9/open.c
index 1fa3c1bc73..4ac81ba5fa 100644
--- a/src/lib9/open.c
+++ b/src/lib9/open.c
@@ -35,16 +35,13 @@ THE SOFTWARE.
 int
 p9open(char *name, int mode)
 {
-	int cexec, rclose;
-	int fd, umode, lock, rdwr;
-	struct flock fl;
+	int rclose;
+	int fd, umode, rdwr;
 
 	rdwr = mode&3;
 	umode = rdwr;
-	cexec = mode&OCEXEC;
 	rclose = mode&ORCLOSE;
-	lock = mode&OLOCK;
-	mode &= ~(3|OCEXEC|ORCLOSE|OLOCK);
+	mode &= ~(3|ORCLOSE);
 	if(mode&OTRUNC){
 		umode |= O_TRUNC;
 		mode ^= OTRUNC;
@@ -53,10 +50,6 @@ p9open(char *name, int mode)
 		umode |= O_DIRECT;
 		mode ^= ODIRECT;
 	}
-	if(mode&ONONBLOCK){
-		umode |= O_NONBLOCK;
-		mode ^= ONONBLOCK;
-	}
 	if(mode&OAPPEND){
 		umode |= O_APPEND;
 		mode ^= OAPPEND;
@@ -65,21 +58,9 @@ p9open(char *name, int mode)
 		werrstr("mode 0x%x not supported", mode);
 		return -1;
 	}
+	umode |= O_BINARY;
 	fd = open(name, umode);
 	if(fd >= 0){
-		if(lock){
-			fl.l_type = (rdwr==OREAD) ? F_RDLCK : F_WRLCK;
-			fl.l_whence = SEEK_SET;
-			fl.l_start = 0;
-			fl.l_len = 0;
-			if(fcntl(fd, F_SETLK, &fl) < 0){
-				close(fd);
-				werrstr("lock: %r");
-				return -1;
-			}
-		}
-		if(cexec)
-			fcntl(fd, F_SETFL, FD_CLOEXEC);
 		if(rclose)
 			remove(name);
 	}
diff --git a/src/lib9/pipe.c b/src/lib9/pipe.c
deleted file mode 100644
index 0a7d073901..0000000000
--- a/src/lib9/pipe.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
-Plan 9 from User Space src/lib9/getenv.c
-http://code.swtch.com/plan9port/src/tip/src/lib9/getenv.c
-
-Copyright 2001-2007 Russ Cox.  All Rights Reserved.
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
-*/
-#include <u.h>
-#define NOPLAN9DEFINES
-#include <libc.h>
-#include <sys/socket.h>
-
-/*
- * We use socketpair to get a two-way pipe.
- * The pipe still doesn't preserve message boundaries.
- * Worse, it cannot be reopened via /dev/fd/NNN on Linux.
- */
-int
-p9pipe(int fd[2])
-{
-	return socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
-}
diff --git a/src/lib9/time.c b/src/lib9/time.c
index ab1b905608..720dd702eb 100644
--- a/src/lib9/time.c
+++ b/src/lib9/time.c
@@ -25,13 +25,18 @@ THE SOFTWARE.
 #include <u.h>
 #include <sys/time.h>
 #include <time.h>
+#ifndef __MINGW32__
 #include <sys/resource.h>
+#endif
 #define NOPLAN9DEFINES
 #include <libc.h>
 
 long
 p9times(long *t)
 {
+#ifdef __MINGW32__
+	memset(t, 0, 4*sizeof(long));
+#else
 	struct rusage ru, cru;
 
 	if(getrusage(0, &ru) < 0 || getrusage(-1, &cru) < 0)
@@ -41,6 +46,7 @@ p9times(long *t)
 	t[1] = ru.ru_stime.tv_sec*1000 + ru.ru_stime.tv_usec/1000;
 	t[2] = cru.ru_utime.tv_sec*1000 + cru.ru_utime.tv_usec/1000;
 	t[3] = cru.ru_stime.tv_sec*1000 + cru.ru_stime.tv_usec/1000;
+#endif
 
 	/* BUG */
 	return t[0]+t[1]+t[2]+t[3];
diff --git a/src/lib9/win32.c b/src/lib9/win32.c
new file mode 100644
index 0000000000..90753bb8d2
--- /dev/null
+++ b/src/lib9/win32.c
@@ -0,0 +1,26 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include <u.h>
+#include <libc.h>
+
+int fork()
+{
+	return -1;
+}
+
+int p9rfork(int flags)
+{
+	return -1;
+}
+
+Waitmsg *p9wait()
+{
+	return 0;
+}
+
+int p9waitpid()
+{
+	return -1;
+}
diff --git a/src/libbio/binit.c b/src/libbio/binit.c
index 6eb7776a85..a7ade5081f 100644
--- a/src/libbio/binit.c
+++ b/src/libbio/binit.c
@@ -87,7 +87,7 @@ Binits(Biobuf *bp, int f, int mode, unsigned char *p, int size)
 	p += Bungetsize;	/* make room for Bungets */
 	size -= Bungetsize;
 
-	switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
+	switch(mode&~(ORCLOSE|OTRUNC)) {
 	default:
 		fprint(2, "Bopen: unknown mode %d\n", mode);
 		return Beof;
@@ -142,7 +142,7 @@ Bopen(char *name, int mode)
 	Biobuf *bp;
 	int f;
 
-	switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
+	switch(mode&~(ORCLOSE|OTRUNC)) {
 	default:
 		fprint(2, "Bopen: unknown mode %d\n", mode);
 		return 0;
@@ -154,7 +154,7 @@ Bopen(char *name, int mode)
 		break;
 
 	case OWRITE:
-		f = creat(name, 0666);
+		f = create(name, OWRITE|OTRUNC, 0666);
 		if(f < 0)
 			return 0;
 	}
diff --git a/src/libbio/bseek.c b/src/libbio/bseek.c
index ee3ba77148..be00ab1a7d 100644
--- a/src/libbio/bseek.c
+++ b/src/libbio/bseek.c
@@ -33,10 +33,12 @@ Bseek(Biobuf *bp, vlong offset, int base)
 	vlong n, d;
 	int bufsz;
 
+#ifndef __MINGW32__
 	if(sizeof(offset) != sizeof(off_t)) {
 		fprint(2, "Bseek: libbio compiled with %d-byte offset\n", sizeof(off_t));
 		abort();
 	}
+#endif
 
 	switch(bp->state) {
 	default:
diff --git a/src/libmach/Makefile b/src/libmach/Makefile
index f1be126d27..69d52c288c 100644
--- a/src/libmach/Makefile
+++ b/src/libmach/Makefile
@@ -47,8 +47,13 @@ OFILES=\
 	5obj.$O\
 	6obj.$O\
 	8obj.$O\
+
+ifneq ($(GOOS),mingw)
+OFILES+=\
 	$(shell uname | tr A-Z a-z).$O\
 
+endif
+
 HFILES=../../include/mach.h elf.h macho.h obj.h
 
 install: $(LIB)
diff --git a/src/make.bash b/src/make.bash
index 5807dbe4e9..c3e7c6c257 100755
--- a/src/make.bash
+++ b/src/make.bash
@@ -31,10 +31,10 @@ amd64 | 386 | arm)
 esac
 
 case "$GOOS" in
-darwin | freebsd | linux | nacl)
+darwin | freebsd | linux | mingw | nacl)
 	;;
 *)
-	echo '$GOOS is set to <'$GOOS'>, must be darwin, freebsd, linux, or nacl' 1>&2
+	echo '$GOOS is set to <'$GOOS'>, must be darwin, freebsd, linux, mingw, or nacl' 1>&2
 	exit 1
 esac