Gid uint64
Members []string
}
+
+// Go does not support slices in map keys; therefore, use this separate struct
type GroupKey struct {
Name string
Passwd string
Gid uint64
- Members string
+ Members string // "," separated
}
func toKey(g Group) GroupKey {
}
// ParseGroups parses a file in the format of /etc/group and returns all
-// entries as Group structs.
+// entries as slice of Group structs.
func ParseGroups(r io.Reader) ([]Group, error) {
var res []Group
- s := bufio.NewScanner(r)
- for s.Scan() {
- t := s.Text()
+ s := bufio.NewReader(r)
+ for {
+ t, err := s.ReadString('\n')
+ if err != nil {
+ if err == io.EOF {
+ break
+ }
+ return nil, err
+ }
x := strings.Split(t, ":")
if len(x) != 4 {
return nil, errors.Wrapf(err, "invalid gid in line %q", t)
}
+ // ReadString() contains the delimiter
+ x[3] = strings.TrimSuffix(x[3], "\n")
+
var members []string
// No members must result in empty slice, not slice with the
// empty string
Members: members,
})
}
- err := s.Err()
- if err != nil {
- return nil, err
- }
return res, nil
}
-func SerializeGroup(g Group) []byte {
+func SerializeGroup(g Group) ([]byte, error) {
le := binary.LittleEndian
// Concatenate all (NUL-terminated) strings and store the offsets
offPasswd := uint16(data.Len())
data.Write([]byte(g.Passwd))
data.WriteByte(0)
- // Padding to align the following uint16
- if data.Len()%2 != 0 {
- data.WriteByte(0)
- }
+ alignBufferTo(&data, 2) // align the following uint16
offMemOff := uint16(data.Len())
// Offsets for group members
offMem := offMemOff + 2*uint16(len(mems_off))
res.Write(data.Bytes())
// We must pad each entry so that all uint64 at the beginning of the
// struct are 8 byte aligned
- l := res.Len()
- if l%8 != 0 {
- for i := 0; i < 8-l%8; i++ {
- res.WriteByte(0)
- }
- }
+ alignBufferTo(&res, 8)
- return res.Bytes()
+ return res.Bytes(), nil
}
func SerializeGroups(w io.Writer, grs []Group) error {
for _, g := range grs {
// TODO: warn about duplicate entries
offsets[toKey(g)] = uint64(data.Len())
- data.Write(SerializeGroup(g))
+ x, err := SerializeGroup(g)
+ if err != nil {
+ return err
+ }
+ data.Write(x)
}
// Copy to prevent sorting from modifying the argument