Imported Upstream version 2011.04.13upstream/2011.04.13

1 files changed, 127 insertions, 0 deletions

diff --git a/src/pkg/os/exec_posix.go b/src/pkg/os/exec_posix.go
new file mode 100644
index 000000000..9102dc0a4
--- /dev/null
+++ b/src/pkg/os/exec_posix.go
@@ -0,0 +1,127 @@
+// 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 "syscall"
+
+// StartProcess starts a new process with the program, arguments and attributes
+// specified by name, argv and attr.
+func StartProcess(name string, argv []string, attr *ProcAttr) (p *Process, err Error) {
+	sysattr := &syscall.ProcAttr{
+		Dir: attr.Dir,
+		Env: attr.Env,
+	}
+	if sysattr.Env == nil {
+		sysattr.Env = Environ()
+	}
+	// Create array of integer (system) fds.
+	intfd := make([]int, len(attr.Files))
+	for i, f := range attr.Files {
+		if f == nil {
+			intfd[i] = -1
+		} else {
+			intfd[i] = f.Fd()
+		}
+	}
+	sysattr.Files = intfd
+
+	pid, h, e := syscall.StartProcess(name, argv, sysattr)
+	if iserror(e) {
+		return nil, &PathError{"fork/exec", name, Errno(e)}
+	}
+	return newProcess(pid, h), nil
+}
+
+// Exec replaces the current process with an execution of the
+// named binary, with arguments argv and environment envv.
+// If successful, Exec never returns.  If it fails, it returns an Error.
+// StartProcess is almost always a better way to execute a program.
+func Exec(name string, argv []string, envv []string) Error {
+	if envv == nil {
+		envv = Environ()
+	}
+	e := syscall.Exec(name, argv, envv)
+	if iserror(e) {
+		return &PathError{"exec", name, Errno(e)}
+	}
+	return nil
+}
+
+// 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 Rusage struct,
+// since syscall one might have different field types across
+// different OS.
+
+// Waitmsg stores the information about an exited process as reported by Wait.
+type Waitmsg struct {
+	Pid                int             // The process's id.
+	syscall.WaitStatus                 // System-dependent status info.
+	Rusage             *syscall.Rusage // System-dependent resource usage info.
+}
+
+// Wait waits for process pid to exit or stop, and then returns a
+// Waitmsg describing its status and an Error, if any. The options
+// (WNOHANG etc.) affect the behavior of the Wait call.
+// Wait is equivalent to calling FindProcess and then Wait
+// and Release on the result.
+func Wait(pid int, options int) (w *Waitmsg, err Error) {
+	p, e := FindProcess(pid)
+	if e != nil {
+		return nil, e
+	}
+	defer p.Release()
+	return p.Wait(options)
+}
+
+// Convert i to decimal string.
+func itod(i int) string {
+	if i == 0 {
+		return "0"
+	}
+
+	u := uint64(i)
+	if i < 0 {
+		u = -u
+	}
+
+	// Assemble decimal in reverse order.
+	var b [32]byte
+	bp := len(b)
+	for ; u > 0; u /= 10 {
+		bp--
+		b[bp] = byte(u%10) + '0'
+	}
+
+	if i < 0 {
+		bp--
+		b[bp] = '-'
+	}
+
+	return string(b[bp:])
+}
+
+func (w Waitmsg) String() string {
+	// TODO(austin) Use signal names when possible?
+	res := ""
+	switch {
+	case w.Exited():
+		res = "exit status " + itod(w.ExitStatus())
+	case w.Signaled():
+		res = "signal " + itod(w.Signal())
+	case w.Stopped():
+		res = "stop signal " + itod(w.StopSignal())
+		if w.StopSignal() == syscall.SIGTRAP && w.TrapCause() != 0 {
+			res += " (trap " + itod(w.TrapCause()) + ")"
+		}
+	case w.Continued():
+		res = "continued"
+	}
+	if w.CoreDump() {
+		res += " (core dumped)"
+	}
+	return res
+}