Golang user.LookupGid函數代碼示例

// LookupGID uses traditional local system files lookup (from libcontainer/user) on a group ID,
// followed by a call to `getent` for supporting host configured non-files passwd and group dbs
func LookupGID(gid int) (user.Group, error) {
	// first try a local system files lookup using existing capabilities
	group, err := user.LookupGid(gid)
	if err == nil {
		return group, nil
	}
	// local files lookup failed; attempt to call `getent` to query configured group dbs
	return getentGroup(fmt.Sprintf("%s %d", "group", gid))
}

func (f *DefFile) Group() (interface{}, error) {
	fi, err := os.Lstat(f.path)
	if err != nil {
		return "", err
	}

	gidS := fmt.Sprint(fi.Sys().(*syscall.Stat_t).Gid)
	gid, err := strconv.Atoi(gidS)
	if err != nil {
		return "", err
	}
	group, err := user.LookupGid(gid)
	if err != nil {
		return "", err
	}

	return group.Name, nil
}

// Parse the remapped root (user namespace) option, which can be one of:
//   username            - valid username from /etc/passwd
//   username:groupname  - valid username; valid groupname from /etc/group
//   uid                 - 32-bit unsigned int valid Linux UID value
//   uid:gid             - uid value; 32-bit unsigned int Linux GID value
//
//  If no groupname is specified, and a username is specified, an attempt
//  will be made to lookup a gid for that username as a groupname
//
//  If names are used, they are verified to exist in passwd/group
func parseRemappedRoot(usergrp string) (string, string, error) {

	var (
		userID, groupID     int
		username, groupname string
	)

	idparts := strings.Split(usergrp, ":")
	if len(idparts) > 2 {
		return "", "", fmt.Errorf("Invalid user/group specification in --userns-remap: %q", usergrp)
	}

	if uid, err := strconv.ParseInt(idparts[0], 10, 32); err == nil {
		// must be a uid; take it as valid
		userID = int(uid)
		luser, err := user.LookupUid(userID)
		if err != nil {
			return "", "", fmt.Errorf("Uid %d has no entry in /etc/passwd: %v", userID, err)
		}
		username = luser.Name
		if len(idparts) == 1 {
			// if the uid was numeric and no gid was specified, take the uid as the gid
			groupID = userID
			lgrp, err := user.LookupGid(groupID)
			if err != nil {
				return "", "", fmt.Errorf("Gid %d has no entry in /etc/group: %v", groupID, err)
			}
			groupname = lgrp.Name
		}
	} else {
		lookupName := idparts[0]
		// special case: if the user specified "default", they want Docker to create or
		// use (after creation) the "dockremap" user/group for root remapping
		if lookupName == defaultIDSpecifier {
			lookupName = defaultRemappedID
		}
		luser, err := user.LookupUser(lookupName)
		if err != nil && idparts[0] != defaultIDSpecifier {
			// error if the name requested isn't the special "dockremap" ID
			return "", "", fmt.Errorf("Error during uid lookup for %q: %v", lookupName, err)
		} else if err != nil {
			// special case-- if the username == "default", then we have been asked
			// to create a new entry pair in /etc/{passwd,group} for which the /etc/sub{uid,gid}
			// ranges will be used for the user and group mappings in user namespaced containers
			_, _, err := idtools.AddNamespaceRangesUser(defaultRemappedID)
			if err == nil {
				return defaultRemappedID, defaultRemappedID, nil
			}
			return "", "", fmt.Errorf("Error during %q user creation: %v", defaultRemappedID, err)
		}
		userID = luser.Uid
		username = luser.Name
		if len(idparts) == 1 {
			// we only have a string username, and no group specified; look up gid from username as group
			group, err := user.LookupGroup(lookupName)
			if err != nil {
				return "", "", fmt.Errorf("Error during gid lookup for %q: %v", lookupName, err)
			}
			groupID = group.Gid
			groupname = group.Name
		}
	}

	if len(idparts) == 2 {
		// groupname or gid is separately specified and must be resolved
		// to a unsigned 32-bit gid
		if gid, err := strconv.ParseInt(idparts[1], 10, 32); err == nil {
			// must be a gid, take it as valid
			groupID = int(gid)
			lgrp, err := user.LookupGid(groupID)
			if err != nil {
				return "", "", fmt.Errorf("Gid %d has no entry in /etc/passwd: %v", groupID, err)
			}
			groupname = lgrp.Name
		} else {
			// not a number; attempt a lookup
			group, err := user.LookupGroup(idparts[1])
			if err != nil {
				return "", "", fmt.Errorf("Error during gid lookup for %q: %v", idparts[1], err)
			}
			groupID = group.Gid
			groupname = idparts[1]
		}
	}
	return username, groupname, nil
}