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// +build linux
package ps
import (
"fmt"
"io"
"io/ioutil"
"os"
"strconv"
"strings"
)
// UnixProcess is an implementation of Process that contains Unix-specific
// fields and information.
type UnixProcess struct {
pid int
ppid int
state rune
pgrp int
sid int
binary string
}
func (p *UnixProcess) Pid() int {
return p.pid
}
func (p *UnixProcess) PPid() int {
return p.ppid
}
func (p *UnixProcess) Executable() string {
return p.binary
}
// Refresh reloads all the data associated with this process.
func (p *UnixProcess) Refresh() error {
statPath := fmt.Sprintf("/proc/%d/stat", p.pid)
dataBytes, err := ioutil.ReadFile(statPath)
if err != nil {
return err
}
// First, parse out the image name
data := string(dataBytes)
binStart := strings.IndexRune(data, '(') + 1
binEnd := strings.IndexRune(data[binStart:], ')')
p.binary = data[binStart : binStart+binEnd]
// Move past the image name and start parsing the rest
data = data[binStart+binEnd+2:]
_, err = fmt.Sscanf(data,
"%c %d %d %d",
&p.state,
&p.ppid,
&p.pgrp,
&p.sid)
return err
}
func findProcess(pid int) (Process, error) {
dir := fmt.Sprintf("/proc/%d", pid)
_, err := os.Stat(dir)
if err != nil {
if os.IsNotExist(err) {
return nil, nil
}
return nil, err
}
return newUnixProcess(pid)
}
func processes() ([]Process, error) {
d, err := os.Open("/proc")
if err != nil {
return nil, err
}
defer d.Close()
results := make([]Process, 0, 50)
for {
fis, err := d.Readdir(10)
if err == io.EOF {
break
}
if err != nil {
return nil, err
}
for _, fi := range fis {
// We only care about directories, since all pids are dirs
if !fi.IsDir() {
continue
}
// We only care if the name starts with a numeric
name := fi.Name()
if name[0] < '0' || name[0] > '9' {
continue
}
// From this point forward, any errors we just ignore, because
// it might simply be that the process doesn't exist anymore.
pid, err := strconv.ParseInt(name, 10, 0)
if err != nil {
continue
}
p, err := newUnixProcess(int(pid))
if err != nil {
continue
}
results = append(results, p)
}
}
return results, nil
}
func newUnixProcess(pid int) (*UnixProcess, error) {
p := &UnixProcess{pid: pid}
return p, p.Refresh()
}
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