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// +build linux
/*
** Zabbix
** Copyright (C) 2001-2021 Zabbix SIA
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
**/
package procfs
import (
"bytes"
"errors"
"fmt"
"strconv"
"strings"
"syscall"
)
const (
kB = 1024
mB = kB * 1024
gB = mB * 1024
tB = gB * 1024
)
// GetMemory reads /proc/meminfo file and returns and returns the value in bytes for the
// specific memory type. Returns an error if the value was not found, or if theres is an issue
// with reading the file or parsing the value.
func GetMemory(memType string) (mem uint64, err error) {
meminfo, err := ReadAll("/proc/meminfo")
if err != nil {
return mem, fmt.Errorf("cannot read meminfo file: %s", err.Error())
}
var found bool
mem, found, err = ByteFromProcFileData(meminfo, memType)
if err != nil {
return mem, fmt.Errorf("cannot get the memory amount for %s: %s", memType, err.Error())
}
if !found {
return mem, fmt.Errorf("cannot get the memory amount for %s", memType)
}
return
}
// ReadAll reads all data from a file. Returns an error if there is an issue with reading the file or
// writing the output.
func ReadAll(filename string) (data []byte, err error) {
fd, err := syscall.Open(filename, syscall.O_RDONLY, 0)
if err != nil {
return
}
defer syscall.Close(fd)
var buf bytes.Buffer
b := make([]byte, 2048)
for {
var n int
if n, err = syscall.Read(fd, b); err != nil {
if errors.Is(err, syscall.EINTR) {
continue
}
return
}
if n == 0 {
return buf.Bytes(), nil
}
if _, err = buf.Write(b[:n]); err != nil {
return
}
}
}
// ByteFromProcFileData returns the value in bytes of the provided value name from the provided
// process file data. Returns true if the value is found, and false if it is not or if there is an
// error. Returns an error if the theres is an issue with parsing values.
func ByteFromProcFileData(data []byte, valueName string) (uint64, bool, error) {
for _, line := range strings.Split(string(data), "\n") {
i := strings.Index(line, ":")
if i < 0 || valueName != line[:i] {
continue
}
line = line[i+1:]
if len(line) < 3 {
continue
}
v, err := strconv.ParseUint(strings.TrimSpace(line[:len(line)-2]), 10, 64)
if err != nil {
return 0, false, err
}
switch line[len(line)-2:] {
case "kB":
v *= kB
case "mB":
v *= mB
case "GB":
v *= gB
case "TB":
v *= tB
default:
return 0, false, errors.New("cannot resolve value type")
}
return v, true, nil
}
return 0, false, nil
}
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