153 lines
4.0 KiB
Go
153 lines
4.0 KiB
Go
// Package aghos contains utilities for functions requiring system calls and
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// other OS-specific APIs. OS-specific network handling should go to aghnet
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// instead.
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package aghos
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import (
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"bufio"
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"fmt"
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"io"
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"io/fs"
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"os"
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"os/exec"
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"path"
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"runtime"
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"slices"
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"strconv"
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"strings"
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"github.com/AdguardTeam/golibs/errors"
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"github.com/AdguardTeam/golibs/log"
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)
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// Default file, binary, and directory permissions.
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const (
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DefaultPermDir fs.FileMode = 0o700
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DefaultPermExe fs.FileMode = 0o700
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DefaultPermFile fs.FileMode = 0o600
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)
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// Unsupported is a helper that returns a wrapped [errors.ErrUnsupported].
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func Unsupported(op string) (err error) {
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return fmt.Errorf("%s: not supported on %s: %w", op, runtime.GOOS, errors.ErrUnsupported)
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}
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// SetRlimit sets user-specified limit of how many fd's we can use.
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//
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// See https://github.com/AdguardTeam/AdGuardHome/internal/issues/659.
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func SetRlimit(val uint64) (err error) {
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return setRlimit(val)
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}
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// HaveAdminRights checks if the current user has root (administrator) rights.
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func HaveAdminRights() (bool, error) {
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return haveAdminRights()
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}
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// MaxCmdOutputSize is the maximum length of performed shell command output in
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// bytes.
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const MaxCmdOutputSize = 64 * 1024
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// RunCommand runs shell command.
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func RunCommand(command string, arguments ...string) (code int, output []byte, err error) {
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cmd := exec.Command(command, arguments...)
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out, err := cmd.Output()
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out = out[:min(len(out), MaxCmdOutputSize)]
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if err != nil {
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if eerr := new(exec.ExitError); errors.As(err, &eerr) {
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return eerr.ExitCode(), eerr.Stderr, nil
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}
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return 1, nil, fmt.Errorf("command %q failed: %w: %s", command, err, out)
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}
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return cmd.ProcessState.ExitCode(), out, nil
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}
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// PIDByCommand searches for process named command and returns its PID ignoring
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// the PIDs from except. If no processes found, the error returned.
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func PIDByCommand(command string, except ...int) (pid int, err error) {
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// Don't use -C flag here since it's a feature of linux's ps
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// implementation. Use POSIX-compatible flags instead.
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//
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// See https://github.com/AdguardTeam/AdGuardHome/issues/3457.
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cmd := exec.Command("ps", "-A", "-o", "pid=", "-o", "comm=")
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var stdout io.ReadCloser
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if stdout, err = cmd.StdoutPipe(); err != nil {
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return 0, fmt.Errorf("getting the command's stdout pipe: %w", err)
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}
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if err = cmd.Start(); err != nil {
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return 0, fmt.Errorf("start command executing: %w", err)
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}
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var instNum int
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pid, instNum, err = parsePSOutput(stdout, command, except)
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if err != nil {
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return 0, err
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}
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if err = cmd.Wait(); err != nil {
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return 0, fmt.Errorf("executing the command: %w", err)
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}
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switch instNum {
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case 0:
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// TODO(e.burkov): Use constant error.
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return 0, fmt.Errorf("no %s instances found", command)
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case 1:
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// Go on.
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default:
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log.Info("warning: %d %s instances found", instNum, command)
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}
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if code := cmd.ProcessState.ExitCode(); code != 0 {
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return 0, fmt.Errorf("ps finished with code %d", code)
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}
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return pid, nil
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}
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// parsePSOutput scans the output of ps searching the largest PID of the process
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// associated with cmdName ignoring PIDs from ignore. A valid line from r
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// should look like these:
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//
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// 123 ./example-cmd
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// 1230 some/base/path/example-cmd
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// 3210 example-cmd
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func parsePSOutput(r io.Reader, cmdName string, ignore []int) (largest, instNum int, err error) {
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s := bufio.NewScanner(r)
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for s.Scan() {
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fields := strings.Fields(s.Text())
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if len(fields) != 2 || path.Base(fields[1]) != cmdName {
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continue
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}
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cur, aerr := strconv.Atoi(fields[0])
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if aerr != nil || cur < 0 || slices.Contains(ignore, cur) {
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continue
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}
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instNum++
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largest = max(largest, cur)
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}
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if err = s.Err(); err != nil {
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return 0, 0, fmt.Errorf("scanning stdout: %w", err)
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}
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return largest, instNum, nil
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}
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// IsOpenWrt returns true if host OS is OpenWrt.
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func IsOpenWrt() (ok bool) {
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return isOpenWrt()
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}
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// SendShutdownSignal sends the shutdown signal to the channel.
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func SendShutdownSignal(c chan<- os.Signal) {
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sendShutdownSignal(c)
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}
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