vendor/github.com/fsouza/go-dockerclient/external/github.com/opencontainers/runc/libcontainer/user/lookup.go

   1 package user
   2
   3 import (
   4         "errors"
   5         "fmt"
   6         "syscall"
   7 )
   8
   9 var (
  10         // The current operating system does not provide the required data for user lookups.
  11         ErrUnsupported = errors.New("user lookup: operating system does not provide passwd-formatted data")
  12 )
  13
  14 func lookupUser(filter func(u User) bool) (User, error) {
  15         // Get operating system-specific passwd reader-closer.
  16         passwd, err := GetPasswd()
  17         if err != nil {
  18                 return User{}, err
  19         }
  20         defer passwd.Close()
  21
  22         // Get the users.
  23         users, err := ParsePasswdFilter(passwd, filter)
  24         if err != nil {
  25                 return User{}, err
  26         }
  27
  28         // No user entries found.
  29         if len(users) == 0 {
  30                 return User{}, fmt.Errorf("no matching entries in passwd file")
  31         }
  32
  33         // Assume the first entry is the "correct" one.
  34         return users[0], nil
  35 }
  36
  37 // CurrentUser looks up the current user by their user id in /etc/passwd. If the
  38 // user cannot be found (or there is no /etc/passwd file on the filesystem),
  39 // then CurrentUser returns an error.
  40 func CurrentUser() (User, error) {
  41         return LookupUid(syscall.Getuid())
  42 }
  43
  44 // LookupUser looks up a user by their username in /etc/passwd. If the user
  45 // cannot be found (or there is no /etc/passwd file on the filesystem), then
  46 // LookupUser returns an error.
  47 func LookupUser(username string) (User, error) {
  48         return lookupUser(func(u User) bool {
  49                 return u.Name == username
  50         })
  51 }
  52
  53 // LookupUid looks up a user by their user id in /etc/passwd. If the user cannot
  54 // be found (or there is no /etc/passwd file on the filesystem), then LookupId
  55 // returns an error.
  56 func LookupUid(uid int) (User, error) {
  57         return lookupUser(func(u User) bool {
  58                 return u.Uid == uid
  59         })
  60 }
  61
  62 func lookupGroup(filter func(g Group) bool) (Group, error) {
  63         // Get operating system-specific group reader-closer.
  64         group, err := GetGroup()
  65         if err != nil {
  66                 return Group{}, err
  67         }
  68         defer group.Close()
  69
  70         // Get the users.
  71         groups, err := ParseGroupFilter(group, filter)
  72         if err != nil {
  73                 return Group{}, err
  74         }
  75
  76         // No user entries found.
  77         if len(groups) == 0 {
  78                 return Group{}, fmt.Errorf("no matching entries in group file")
  79         }
  80
  81         // Assume the first entry is the "correct" one.
  82         return groups[0], nil
  83 }
  84
  85 // CurrentGroup looks up the current user's group by their primary group id's
  86 // entry in /etc/passwd. If the group cannot be found (or there is no
  87 // /etc/group file on the filesystem), then CurrentGroup returns an error.
  88 func CurrentGroup() (Group, error) {
  89         return LookupGid(syscall.Getgid())
  90 }
  91
  92 // LookupGroup looks up a group by its name in /etc/group. If the group cannot
  93 // be found (or there is no /etc/group file on the filesystem), then LookupGroup
  94 // returns an error.
  95 func LookupGroup(groupname string) (Group, error) {
  96         return lookupGroup(func(g Group) bool {
  97                 return g.Name == groupname
  98         })
  99 }
 100
 101 // LookupGid looks up a group by its group id in /etc/group. If the group cannot
 102 // be found (or there is no /etc/group file on the filesystem), then LookupGid
 103 // returns an error.
 104 func LookupGid(gid int) (Group, error) {
 105         return lookupGroup(func(g Group) bool {
 106                 return g.Gid == gid
 107         })
 108 }