add os.ForkExec, os.Exec, os.Wait, exec.OpenCmd.

as thread-safe as possible, given the surrounding system.
add stub RWLock implementation.

R=r
DELTA=852  (834 added, 6 deleted, 12 changed)
OCL=25046
CL=25053

1 files changed, 70 insertions, 0 deletions

diff --git a/src/lib/os/exec.go b/src/lib/os/exec.go
new file mode 100644
index 000000000..0ce51773c
--- /dev/null
+++ b/src/lib/os/exec.go
@@ -0,0 +1,70 @@
+// 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.
+
+package os
+
+import (
+	"os";
+	"syscall";
+)
+
+func ForkExec(argv0 string, argv []string, envv []string, fd []*FD)
+	(pid int, err *Error)
+{
+	// Create array of integer (system) fds.
+	intfd := make([]int64, len(fd));
+	for i, f := range(fd) {
+		if f == nil {
+			intfd[i] = -1;
+		} else {
+			intfd[i] = f.Fd();
+		}
+	}
+
+	p, e := syscall.ForkExec(argv0, argv, envv, intfd);
+	return int(p), ErrnoToError(e);
+}
+
+func Exec(argv0 string, argv []string, envv []string) *Error {
+	e := syscall.Exec(argv0, argv, envv);
+	return ErrnoToError(e);
+}
+
+// TODO(rsc): Should os implement its own syscall.WaitStatus
+// wrapper with the methods, or is exposing the underlying one enough?
+//
+// TODO(rsc): Certainly need to have os.Rusage struct,
+// since syscall one might have different field types across
+// different OS.
+
+type Waitmsg struct {
+	Pid int;
+	syscall.WaitStatus;
+	Rusage *syscall.Rusage;
+}
+
+const (
+	WNOHANG = syscall.WNOHANG;
+	WSTOPPED = syscall.WSTOPPED;
+	WRUSAGE = 1<<60;
+)
+
+func Wait(pid int, options uint64) (w *Waitmsg, err *Error) {
+	var status syscall.WaitStatus;
+	var rusage *syscall.Rusage;
+	if options & WRUSAGE != 0 {
+		rusage = new(syscall.Rusage);
+		options ^= WRUSAGE;
+	}
+	pid1, e := syscall.Wait4(int64(pid), &status, int64(options), rusage);
+	if e != 0 {
+		return nil, ErrnoToError(e);
+	}
+	w = new(Waitmsg);
+	w.Pid = pid;
+	w.WaitStatus = status;
+	w.Rusage = rusage;
+	return w, nil;
+}
+