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|
package continuity
import (
"bufio"
"fmt"
"io"
"os"
"strconv"
"strings"
)
// TODO(stevvooe): This needs a lot of work before we can call it useful.
type groupIndex struct {
byName map[string]*group
byGID map[int]*group
}
func getGroupIndex() (*groupIndex, error) {
f, err := os.Open("/etc/group")
if err != nil {
return nil, err
}
defer f.Close()
groups, err := parseGroups(f)
if err != nil {
return nil, err
}
return newGroupIndex(groups), nil
}
func newGroupIndex(groups []group) *groupIndex {
gi := &groupIndex{
byName: make(map[string]*group),
byGID: make(map[int]*group),
}
for i, group := range groups {
gi.byGID[group.gid] = &groups[i]
gi.byName[group.name] = &groups[i]
}
return gi
}
type group struct {
name string
gid int
members []string
}
func getGroupName(gid int) (string, error) {
f, err := os.Open("/etc/group")
if err != nil {
return "", err
}
defer f.Close()
groups, err := parseGroups(f)
if err != nil {
return "", err
}
for _, group := range groups {
if group.gid == gid {
return group.name, nil
}
}
return "", fmt.Errorf("no group for gid")
}
// parseGroups parses an /etc/group file for group names, ids and membership.
// This is unix specific.
func parseGroups(rd io.Reader) ([]group, error) {
var groups []group
scanner := bufio.NewScanner(rd)
for scanner.Scan() {
if strings.HasPrefix(scanner.Text(), "#") {
continue // skip comment
}
parts := strings.SplitN(scanner.Text(), ":", 4)
if len(parts) != 4 {
return nil, fmt.Errorf("bad entry: %q", scanner.Text())
}
name, _, sgid, smembers := parts[0], parts[1], parts[2], parts[3]
gid, err := strconv.Atoi(sgid)
if err != nil {
return nil, fmt.Errorf("bad gid: %q", gid)
}
members := strings.Split(smembers, ",")
groups = append(groups, group{
name: name,
gid: gid,
members: members,
})
}
if scanner.Err() != nil {
return nil, scanner.Err()
}
return groups, nil
}
|
