consul/vendor/github.com/opencontainers/runc/libcontainer/user/lookup.go

111 lines
3.1 KiB
Go

package user
import (
"errors"
"syscall"
)
var (
// The current operating system does not provide the required data for user lookups.
ErrUnsupported = errors.New("user lookup: operating system does not provide passwd-formatted data")
// No matching entries found in file.
ErrNoPasswdEntries = errors.New("no matching entries in passwd file")
ErrNoGroupEntries = errors.New("no matching entries in group file")
)
func lookupUser(filter func(u User) bool) (User, error) {
// Get operating system-specific passwd reader-closer.
passwd, err := GetPasswd()
if err != nil {
return User{}, err
}
defer passwd.Close()
// Get the users.
users, err := ParsePasswdFilter(passwd, filter)
if err != nil {
return User{}, err
}
// No user entries found.
if len(users) == 0 {
return User{}, ErrNoPasswdEntries
}
// Assume the first entry is the "correct" one.
return users[0], nil
}
// CurrentUser looks up the current user by their user id in /etc/passwd. If the
// user cannot be found (or there is no /etc/passwd file on the filesystem),
// then CurrentUser returns an error.
func CurrentUser() (User, error) {
return LookupUid(syscall.Getuid())
}
// LookupUser looks up a user by their username in /etc/passwd. If the user
// cannot be found (or there is no /etc/passwd file on the filesystem), then
// LookupUser returns an error.
func LookupUser(username string) (User, error) {
return lookupUser(func(u User) bool {
return u.Name == username
})
}
// LookupUid looks up a user by their user id in /etc/passwd. If the user cannot
// be found (or there is no /etc/passwd file on the filesystem), then LookupId
// returns an error.
func LookupUid(uid int) (User, error) {
return lookupUser(func(u User) bool {
return u.Uid == uid
})
}
func lookupGroup(filter func(g Group) bool) (Group, error) {
// Get operating system-specific group reader-closer.
group, err := GetGroup()
if err != nil {
return Group{}, err
}
defer group.Close()
// Get the users.
groups, err := ParseGroupFilter(group, filter)
if err != nil {
return Group{}, err
}
// No user entries found.
if len(groups) == 0 {
return Group{}, ErrNoGroupEntries
}
// Assume the first entry is the "correct" one.
return groups[0], nil
}
// CurrentGroup looks up the current user's group by their primary group id's
// entry in /etc/passwd. If the group cannot be found (or there is no
// /etc/group file on the filesystem), then CurrentGroup returns an error.
func CurrentGroup() (Group, error) {
return LookupGid(syscall.Getgid())
}
// LookupGroup looks up a group by its name in /etc/group. If the group cannot
// be found (or there is no /etc/group file on the filesystem), then LookupGroup
// returns an error.
func LookupGroup(groupname string) (Group, error) {
return lookupGroup(func(g Group) bool {
return g.Name == groupname
})
}
// LookupGid looks up a group by its group id in /etc/group. If the group cannot
// be found (or there is no /etc/group file on the filesystem), then LookupGid
// returns an error.
func LookupGid(gid int) (Group, error) {
return lookupGroup(func(g Group) bool {
return g.Gid == gid
})
}