smaps.go

package main

import (
	"bufio"
	"flag"
	"fmt"
	"log"
	"os"
	"sort"
	"strconv"
	"strings"
)

func main() {
	flag.Parse()
	if err := run(); err != nil {
		log.Fatal(err)
	}
}

func run() error {
	pid, err := strconv.Atoi(flag.Arg(0))
	if err != nil {
		return err
	}
	smaps, err := getMaps(pid)
	if err != nil {
		return err
	}
	sorted := keys(smaps)
	for _, k := range sorted {
		fmt.Printf("%s %d\n", k, smaps[k])
	}
	return nil
}

func getMaps(pid int) (map[string]int, error) {
	f, err := os.Open(fmt.Sprintf("/proc/%d/smaps", pid))
	if err != nil {
		return nil, err
	}
	defer f.Close()
	var (
		smaps = make(map[string]int)
		s     = bufio.NewScanner(f)
	)
	for s.Scan() {
		var (
			fields = strings.Fields(s.Text())
			name   = fields[0]
		)
		if len(fields) < 2 {
			continue
		}
		n, err := strconv.Atoi(fields[1])
		if err != nil {
			continue
		}
		smaps[name] += n
	}
	if err := s.Err(); err != nil {
		return nil, err
	}
	return smaps, nil
}

func keys(smaps map[string]int) []string {
	var o []string
	for k := range smaps {
		o = append(o, k)
	}
	sort.Strings(o)
	return o
}