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package sys
import (
"errors"
"fmt"
"log"
"os"
"os/exec"
"strconv"
"sync"
"hakurei.app/container"
"hakurei.app/hst"
"hakurei.app/internal"
"hakurei.app/internal/hlog"
)
// Hsu caches responses from cmd/hsu.
type Hsu struct {
idOnce sync.Once
idErr error
id int
}
var ErrHsuAccess = errors.New("current user is not in the hsurc file")
func (h *Hsu) Uid(identity int) (int, error) {
h.idOnce.Do(func() {
h.id = -1
hsuPath := internal.MustHsuPath()
cmd := exec.Command(hsuPath)
cmd.Path = hsuPath
cmd.Stderr = os.Stderr // pass through fatal messages
cmd.Env = make([]string, 0)
cmd.Dir = container.FHSRoot
var (
p []byte
exitError *exec.ExitError
)
const step = "obtain uid from hsu"
if p, h.idErr = cmd.Output(); h.idErr == nil {
h.id, h.idErr = strconv.Atoi(string(p))
if h.idErr != nil {
h.idErr = &hst.AppError{Step: step, Err: h.idErr, Msg: "invalid uid string from hsu"}
}
} else if errors.As(h.idErr, &exitError) && exitError != nil && exitError.ExitCode() == 1 {
// hsu prints an error message in this case
h.idErr = &hst.AppError{Step: step, Err: ErrHsuAccess}
} else if os.IsNotExist(h.idErr) {
h.idErr = &hst.AppError{Step: step, Err: os.ErrNotExist,
Msg: fmt.Sprintf("the setuid helper is missing: %s", hsuPath)}
}
})
uid := -1
if h.id >= 0 {
uid = 1000000 + h.id*10000 + identity
}
return uid, h.idErr
}
// MustUid calls [State.Uid] and terminates on error.
func MustUid(s State, identity int) int {
uid, err := s.Uid(identity)
if err == nil {
return uid
}
const fallback = "cannot obtain uid from setuid wrapper:"
if errors.Is(err, ErrHsuAccess) {
hlog.Verbose("*"+fallback, err)
os.Exit(1)
return -0xdeadbeef
} else if m, ok := container.GetErrorMessage(err); ok {
log.Fatal(m)
return -0xdeadbeef
} else {
log.Fatalln(fallback, err)
return -0xdeadbeef
}
}
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