tailscale/util/pidowner/pidowner_linux.go
Will Norris 71029cea2d all: update copyright and license headers
This updates all source files to use a new standard header for copyright
and license declaration.  Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.

This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.

Updates #6865

Signed-off-by: Will Norris <will@tailscale.com>
2023-01-27 15:36:29 -08:00

37 lines
687 B
Go

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