// 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 ( "runtime" "sync" "sync/atomic" "syscall" "time" ) // Process stores the information about a process created by StartProcess. type Process struct { Pid int handle uintptr // handle is accessed atomically on Windows isdone uint32 // process has been successfully waited on, non zero if true sigMu sync.RWMutex // avoid race between wait and signal } func newProcess(pid int, handle uintptr) *Process { p := &Process{Pid: pid, handle: handle} runtime.SetFinalizer(p, (*Process).Release) return p } func (p *Process) setDone() { atomic.StoreUint32(&p.isdone, 1) } func (p *Process) done() bool { return atomic.LoadUint32(&p.isdone) > 0 } // ProcAttr holds the attributes that will be applied to a new process // started by StartProcess. type ProcAttr struct { // If Dir is non-empty, the child changes into the directory before // creating the process. Dir string // If Env is non-nil, it gives the environment variables for the // new process in the form returned by Environ. // If it is nil, the result of Environ will be used. Env []string // Files specifies the open files inherited by the new process. The // first three entries correspond to standard input, standard output, and // standard error. An implementation may support additional entries, // depending on the underlying operating system. A nil entry corresponds // to that file being closed when the process starts. Files []*File // Operating system-specific process creation attributes. // Note that setting this field means that your program // may not execute properly or even compile on some // operating systems. Sys *syscall.SysProcAttr } // A Signal represents an operating system signal. // The usual underlying implementation is operating system-dependent: // on Unix it is syscall.Signal. type Signal interface { String() string Signal() // to distinguish from other Stringers } // Getpid returns the process id of the caller. func Getpid() int { return syscall.Getpid() } // Getppid returns the process id of the caller's parent. func Getppid() int { return syscall.Getppid() } // FindProcess looks for a running process by its pid. // // The Process it returns can be used to obtain information // about the underlying operating system process. // // On Unix systems, FindProcess always succeeds and returns a Process // for the given pid, regardless of whether the process exists. func FindProcess(pid int) (*Process, error) { return findProcess(pid) } // StartProcess starts a new process with the program, arguments and attributes // specified by name, argv and attr. // // StartProcess is a low-level interface. The os/exec package provides // higher-level interfaces. // // If there is an error, it will be of type *PathError. func StartProcess(name string, argv []string, attr *ProcAttr) (*Process, error) { return startProcess(name, argv, attr) } // Release releases any resources associated with the Process p, // rendering it unusable in the future. // Release only needs to be called if Wait is not. func (p *Process) Release() error { return p.release() } // Kill causes the Process to exit immediately. func (p *Process) Kill() error { return p.kill() } // Wait waits for the Process to exit, and then returns a // ProcessState describing its status and an error, if any. // Wait releases any resources associated with the Process. // On most operating systems, the Process must be a child // of the current process or an error will be returned. func (p *Process) Wait() (*ProcessState, error) { return p.wait() } // Signal sends a signal to the Process. // Sending Interrupt on Windows is not implemented. func (p *Process) Signal(sig Signal) error { return p.signal(sig) } // UserTime returns the user CPU time of the exited process and its children. func (p *ProcessState) UserTime() time.Duration { return p.userTime() } // SystemTime returns the system CPU time of the exited process and its children. func (p *ProcessState) SystemTime() time.Duration { return p.systemTime() } // Exited reports whether the program has exited. func (p *ProcessState) Exited() bool { return p.exited() } // Success reports whether the program exited successfully, // such as with exit status 0 on Unix. func (p *ProcessState) Success() bool { return p.success() } // Sys returns system-dependent exit information about // the process. Convert it to the appropriate underlying // type, such as syscall.WaitStatus on Unix, to access its contents. func (p *ProcessState) Sys() interface{} { return p.sys() } // SysUsage returns system-dependent resource usage information about // the exited process. Convert it to the appropriate underlying // type, such as *syscall.Rusage on Unix, to access its contents. // (On Unix, *syscall.Rusage matches struct rusage as defined in the // getrusage(2) manual page.) func (p *ProcessState) SysUsage() interface{} { return p.sysUsage() }