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|
package acl
import (
"fmt"
"os"
"sort"
"strings"
)
type Perm uint
const (
PermR = 4
PermW = 2
PermX = 1
)
func (p Perm) String() string {
s := []byte{'r', 'w', 'x'}
if p&PermR == 0 {
s[0] = '-'
}
if p&PermW == 0 {
s[1] = '-'
}
if p&PermX == 0 {
s[2] = '-'
}
return string(s)
}
type QualifiedPerms map[string]Perm
func (a QualifiedPerms) Equals(b QualifiedPerms) bool {
if len(a) != len(b) {
return false
}
for k, va := range a {
if vb, ok := b[k]; !ok || vb != va {
return false
}
}
return true
}
type ACL struct {
User, Group, Other, Mask QualifiedPerms
}
func (acl *ACL) Init() {
acl.User = make(QualifiedPerms)
acl.Group = make(QualifiedPerms)
acl.Other = make(QualifiedPerms)
acl.Mask = make(QualifiedPerms)
}
func ACLFromUnixPerms(perms os.FileMode) (acl ACL) {
perms &= os.ModePerm
acl.User = QualifiedPerms{"": Perm(7 & (perms >> 6))}
acl.Group = QualifiedPerms{"": Perm(7 & (perms >> 3))}
acl.Other = QualifiedPerms{"": Perm(7 & perms)}
return acl
}
func (acl ACL) ToUnixPerms() (m os.FileMode) {
if p, ok := acl.User[""]; ok {
m |= os.FileMode(p << 6)
}
if p, ok := acl.Group[""]; ok {
m |= os.FileMode(p << 3)
}
if p, ok := acl.Other[""]; ok {
m |= os.FileMode(p)
}
return
}
func stringifyAclCategory(parts []string, t string, perms QualifiedPerms) []string {
keys := make([]string, 0, len(perms))
for k := range perms {
keys = append(keys, k)
}
sort.Strings(keys)
for _, k := range keys {
parts = append(parts, t+":"+k+":"+perms[k].String())
}
return parts
}
func (acl ACL) String() string {
parts := []string{}
parts = stringifyAclCategory(parts, "u", acl.User)
parts = stringifyAclCategory(parts, "g", acl.Group)
parts = stringifyAclCategory(parts, "o", acl.Other)
parts = stringifyAclCategory(parts, "m", acl.Mask)
return strings.Join(parts, ",")
}
// ParseACL parses a POSIX ACL. Only the short text form is supported
func ParseACL(s string) (ACL, error) {
acl := ACL{}
acl.Init()
entries := strings.Split(s, ",")
for i, entry := range entries {
entry = strings.TrimSpace(entry)
parts := strings.Split(entry, ":")
if len(parts) != 3 {
return acl, fmt.Errorf("invalid acl: Entry #%d has more or less than 3 ':' separated parts", i+1)
}
var perms *QualifiedPerms = nil
switch parts[0] {
case "u", "user":
perms = &acl.User
case "g", "group":
perms = &acl.Group
case "o", "other":
perms = &acl.Other
case "m", "mask":
perms = &acl.Mask
default:
return acl, fmt.Errorf("invalid acl: Entry #%d has unknown tag \"%s\"", i+1, parts[0])
}
perm := Perm(0)
if strings.Contains(parts[2], "r") {
perm |= PermR
}
if strings.Contains(parts[2], "w") {
perm |= PermW
}
if strings.Contains(parts[2], "x") {
perm |= PermX
}
(*perms)[parts[1]] = perm
}
return acl, nil
}
func (a ACL) Equals(b ACL) bool {
return a.User.Equals(b.User) &&
a.Group.Equals(b.Group) &&
a.Other.Equals(b.Other) &&
a.Mask.Equals(b.Mask)
}
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