/
users.go
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/
users.go
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//
// Copyright © 2016-2017 Ikey Doherty <ikey@solus-project.com>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
package builder
import (
"bufio"
"fmt"
"os"
"path/filepath"
"strconv"
"strings"
)
// A User is an /etc/passwd defined user
type User struct {
Name string // User Name
UID int // User ID
GID int // User primary Group ID
Gecos string // User Gecos (Pretty name)
Home string // User home directory
Shell string // User shell program
}
// A Group is an /etc/group defined user
type Group struct {
Name string // Group Name
ID int // Group ID
Members []string // Names of users in group
}
// Passwd is a simple helper to parse passwd files from a chroot
type Passwd struct {
Users map[string]*User
Groups map[string]*Group
}
// NewPasswd will parse the given path and return a friendly representation
// of those files
func NewPasswd(path string) (*Passwd, error) {
passwdPath := filepath.Join(path, "passwd")
groupPath := filepath.Join(path, "group")
var err error
ret := &Passwd{}
if ret.Users, err = ParseUsers(passwdPath); err != nil {
return nil, err
}
if ret.Groups, err = ParseGroups(groupPath); err != nil {
return nil, err
}
return ret, nil
}
// ParseUsers will attempt to parse a *NIX style passwd file
func ParseUsers(passwd string) (map[string]*User, error) {
fi, err := os.Open(passwd)
if err != nil {
return nil, err
}
defer fi.Close()
ret := make(map[string]*User)
sc := bufio.NewScanner(fi)
for sc.Scan() {
line := sc.Text()
splits := strings.Split(line, ":")
if len(splits) != 7 {
return nil, fmt.Errorf("Invalid number of fields in passwd file: %d", len(splits))
}
user := &User{
Name: strings.TrimSpace(splits[0]),
Gecos: strings.TrimSpace(splits[4]),
Home: strings.TrimSpace(splits[5]),
Shell: strings.TrimSpace(splits[6]),
}
// Parse the uid/gid
if uid, err := strconv.Atoi(strings.TrimSpace(splits[2])); err == nil {
user.UID = uid
} else {
return nil, err
}
if gid, err := strconv.Atoi(strings.TrimSpace(splits[3])); err == nil {
user.GID = gid
} else {
return nil, err
}
// Success
ret[user.Name] = user
}
if err := sc.Err(); err != nil {
return nil, err
}
return ret, nil
}
// ParseGroups will attempt to parse a *NIX style group file
func ParseGroups(grps string) (map[string]*Group, error) {
fi, err := os.Open(grps)
if err != nil {
return nil, err
}
defer fi.Close()
ret := make(map[string]*Group)
sc := bufio.NewScanner(fi)
for sc.Scan() {
line := sc.Text()
splits := strings.Split(line, ":")
if len(splits) != 4 {
return nil, fmt.Errorf("Invalid number of fields in group file: %d", len(splits))
}
group := &Group{
Name: strings.TrimSpace(splits[0]),
}
// So we don't get one empty member situation
membs := strings.TrimSpace(splits[3])
if membs != "" {
group.Members = strings.Split(membs, ",")
}
// Parse the gid
if gid, err := strconv.Atoi(strings.TrimSpace(splits[2])); err == nil {
group.ID = gid
} else {
return nil, err
}
// Success
ret[group.Name] = group
}
if err := sc.Err(); err != nil {
return nil, err
}
return ret, nil
}