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// SPDX-License-Identifier: BSD-3-Clause
//go:build freebsd || openbsd || netbsd
package mem
import (
"context"
"fmt"
"strconv"
"strings"
)
const swapCommand = "swapctl"
// swapctl column indexes
const (
nameCol = 0
totalKiBCol = 1
usedKiBCol = 2
)
func SwapDevices() ([]*SwapDevice, error) {
return SwapDevicesWithContext(context.Background())
}
func SwapDevicesWithContext(ctx context.Context) ([]*SwapDevice, error) {
output, err := invoke.CommandWithContext(ctx, swapCommand, "-lk")
if err != nil {
return nil, fmt.Errorf("could not execute %q: %w", swapCommand, err)
}
return parseSwapctlOutput(string(output))
}
func parseSwapctlOutput(output string) ([]*SwapDevice, error) {
lines := strings.Split(output, "\n")
if len(lines) == 0 {
return nil, fmt.Errorf("could not parse output of %q: no lines in %q", swapCommand, output)
}
// Check header headerFields are as expected.
header := lines[0]
header = strings.ToLower(header)
header = strings.ReplaceAll(header, ":", "")
headerFields := strings.Fields(header)
if len(headerFields) < usedKiBCol {
return nil, fmt.Errorf("couldn't parse %q: too few fields in header %q", swapCommand, header)
}
if headerFields[nameCol] != "device" {
return nil, fmt.Errorf("couldn't parse %q: expected %q to be %q", swapCommand, headerFields[nameCol], "device")
}
if headerFields[totalKiBCol] != "1kb-blocks" && headerFields[totalKiBCol] != "1k-blocks" {
return nil, fmt.Errorf("couldn't parse %q: expected %q to be %q", swapCommand, headerFields[totalKiBCol], "1kb-blocks")
}
if headerFields[usedKiBCol] != "used" {
return nil, fmt.Errorf("couldn't parse %q: expected %q to be %q", swapCommand, headerFields[usedKiBCol], "used")
}
var swapDevices []*SwapDevice
for _, line := range lines[1:] {
if line == "" {
continue // the terminal line is typically empty
}
fields := strings.Fields(line)
if len(fields) < usedKiBCol {
return nil, fmt.Errorf("couldn't parse %q: too few fields", swapCommand)
}
totalKiB, err := strconv.ParseUint(fields[totalKiBCol], 10, 64)
if err != nil {
return nil, fmt.Errorf("couldn't parse 'Size' column in %q: %w", swapCommand, err)
}
usedKiB, err := strconv.ParseUint(fields[usedKiBCol], 10, 64)
if err != nil {
return nil, fmt.Errorf("couldn't parse 'Used' column in %q: %w", swapCommand, err)
}
swapDevices = append(swapDevices, &SwapDevice{
Name: fields[nameCol],
UsedBytes: usedKiB * 1024,
FreeBytes: (totalKiB - usedKiB) * 1024,
})
}
return swapDevices, nil
}
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