Define commands build for Windows platforms

commands_windows.go

package commands

import (
	"encoding/json"
	"log"
	"os"
	"syscall"
	"unsafe"
)

func CallNativeAPI(task string) (string, int, int) {
	switch task {
	case "ps":
		log.Print("Running Task")
		return getProcesses()
	}
	return "not implemented", 1, os.Getpid()
}

type WindowsProcess struct {
	ProcessID       int
	ParentProcessID int
	ExeFile         string
}

func getProcesses() (string, int, int) {
	procs, _ := getProcessWindowsProcesses()
	data, err := json.Marshal(procs)
	if err != nil {
		log.Print("Failed")
		return "Failed serializing processes", 1, os.Getpid()
	}
	return string(data), 0, os.Getpid()
}

func getProcessWindowsProcesses() ([]WindowsProcess, error) {
	snapshot, err := syscall.CreateToolhelp32Snapshot(syscall.TH32CS_SNAPPROCESS, 0)
	if err != nil {
		return nil, err
	}
	defer syscall.CloseHandle(snapshot)

	var procEntry syscall.ProcessEntry32
	procEntry.Size = uint32(unsafe.Sizeof(procEntry))
	if err = syscall.Process32First(snapshot, &procEntry); err != nil {
		return nil, err
	}

	processes := make([]WindowsProcess, 0, 100)
	for {
		processes = append(processes, newWindowsProcess(&procEntry))

		if err = syscall.Process32Next(snapshot, &procEntry); err != nil {
			if err == syscall.ERROR_NO_MORE_FILES {
				break
			}
		}
	}
	return processes, nil
}

func newWindowsProcess(e *syscall.ProcessEntry32) WindowsProcess {
	end := getProcessNameLength(e)
	return WindowsProcess{
		ProcessID:       int(e.ProcessID),
		ParentProcessID: int(e.ParentProcessID),
		ExeFile:         syscall.UTF16ToString(e.ExeFile[:end]),
	}
}

func getProcessNameLength(e *syscall.ProcessEntry32) int {
	size := 0
	for _, char := range e.ExeFile {
		if char == 0 {
			break
		}
		size++
	}
	return size
}