tailscale/util/pidowner/pidowner_linux.go
Brad Fitzpatrick 01185e436f types/result, util/lineiter: add package for a result type, use it
This adds a new generic result type (motivated by golang/go#70084) to
try it out, and uses it in the new lineutil package (replacing the old
lineread package), changing that package to return iterators:
sometimes over []byte (when the input is all in memory), but sometimes
iterators over results of []byte, if errors might happen at runtime.

Updates #12912
Updates golang/go#70084

Change-Id: Iacdc1070e661b5fb163907b1e8b07ac7d51d3f83
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2024-11-05 10:27:52 -08:00

37 lines
700 B
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package pidowner
import (
"fmt"
"os"
"strings"
"tailscale.com/util/lineiter"
)
func ownerOfPID(pid int) (userID string, err error) {
file := fmt.Sprintf("/proc/%d/status", pid)
for lr := range lineiter.File(file) {
line, err := lr.Value()
if err != nil {
if os.IsNotExist(err) {
return "", ErrProcessNotFound
}
return "", err
}
if len(line) < 4 || string(line[:4]) != "Uid:" {
continue
}
f := strings.Fields(string(line))
if len(f) >= 2 {
userID = f[1] // real userid
}
}
if userID == "" {
return "", fmt.Errorf("missing Uid line in %s", file)
}
return userID, nil
}