pstree

README

pstree

pstree is a simple minded package to retrieve the process tree from a given PID.

Installation

sh> go get codeberg.org/sbinet/pstree

Documentation

Documentation is available on godoc:

https://godoc.org/codeberg.org/sbinet/pstree

Example

package main

import (
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"

	"codeberg.org/sbinet/pstree"
)

func main() {
	pid, err := strconv.Atoi(os.Args[1])
	if err != nil {
		log.Fatalf("could not retrieve pid: %v\n", err)
	}
	tree, err := pstree.New()
	if err != nil {
		log.Fatalf("error: %v\n", err)
	}

	fmt.Printf("tree[%d]: %v\n", pid, tree.Procs[pid])
	display(pid, tree, 1)
}

func display(pid int, tree *pstree.Tree, indent int) {
	str := strings.Repeat("  ", indent)
	for _, cid := range tree.Procs[pid].Children {
		proc := tree.Procs[cid]
		fmt.Printf("%s%#v\n", str, proc)
		display(cid, tree, indent+1)
	}
}

Documentation

Overview

Package pstree provides an API to retrieve the process tree from procfs.

Index

• type Process
• type ProcessStat
• type Tree
  • func New() (*Tree, error)

Types

type Process

type Process struct {
	Name     string      `json:"name"`
	Stat     ProcessStat `json:"stat"`
	Children []int       `json:"children"`
}

Process stores information about a UNIX process.

type ProcessStat

type ProcessStat struct {
	PID       int    `json:"pid"`       // process ID
	Comm      string `json:"comm"`      // filename of the executable in parentheses
	State     byte   `json:"state"`     // process state
	Ppid      int    `json:"ppid"`      // pid of the parent process
	Pgrp      int    `json:"pgrp"`      // process group ID of the process
	Session   int    `json:"session"`   // session ID of the process
	TTY       int    `json:"tty"`       // controlling terminal of the process
	Tpgid     int    `json:"tpgid"`     // ID of foreground process group
	Flags     uint32 `json:"flags"`     // kernel flags word of the process
	Minflt    uint64 `json:"minflt"`    // number of minor faults the process has made which have not required loading a memory page from disk
	Cminflt   uint64 `json:"cminflt"`   // number of minor faults the process's waited-for children have made
	Majflt    uint64 `json:"majflt"`    // number of major faults the process has made which have required loading a memory page from disk
	Cmajflt   uint64 `json:"cmajflt"`   // number of major faults the process's waited-for children have made
	Utime     uint64 `json:"utime"`     // user time in clock ticks
	Stime     uint64 `json:"stime"`     // system time in clock ticks
	Cutime    int64  `json:"cutime"`    // children user time in clock ticks
	Cstime    int64  `json:"cstime"`    // children system time in clock ticks
	Priority  int64  `json:"priority"`  // priority
	Nice      int64  `json:"nice"`      // the nice value
	Nthreads  int64  `json:"nthreads"`  // number of threads in this process
	Itrealval int64  `json:"itrealval"` // time in jiffies before next SIGALRM is sent to the process due to an interval timer
	Starttime int64  `json:"starttime"` // time the process started after system boot in clock ticks
	Vsize     uint64 `json:"vsize"`     // virtual memory size in bytes
	RSS       int64  `json:"rss"`       // resident set size: number of pages the process has in real memory

	Environ string `json:"environ"` // environment for the process
	Cwd     string `json:"cwd"`     // current working directory for the process
	Cmdline string `json:"cmdline"` // complete command line for the process
}

ProcessStat contains process information. see: http://man7.org/linux/man-pages/man5/proc.5.html

type Tree

type Tree struct {
	Procs map[int]Process `json:"procs"`
}

Tree is a tree of processes.

func New

func New() (*Tree, error)

New returns the whole system process tree.