diff options
Diffstat (limited to 'acl/acl.go')
| -rw-r--r-- | acl/acl.go | 202 |
1 files changed, 190 insertions, 12 deletions
@@ -1,19 +1,197 @@ // Package acl implements simple ACL manipulation via libacl. package acl -type Perms []Perm +import ( + "errors" + "runtime" + "syscall" + "unsafe" +) -func (ps Perms) String() string { - var s = []byte("---") - for _, p := range ps { - switch p { - case Read: - s[0] = 'r' - case Write: - s[1] = 'w' - case Execute: - s[2] = 'x' +/* +#cgo linux pkg-config: --static libacl + +#include <stdlib.h> +#include <sys/acl.h> +#include <acl/libacl.h> + +static acl_t _go_acl_get_file(const char *path_p, acl_type_t type) { + acl_t acl = acl_get_file(path_p, type); + free((void *)path_p); + return acl; +} + +static int _go_acl_set_file(const char *path_p, acl_type_t type, acl_t acl) { + if (acl_valid(acl) != 0) { + return -1; + } + + int ret = acl_set_file(path_p, type, acl); + free((void *)path_p); + return ret; +} +*/ +import "C" + +func getFile(name string, t C.acl_type_t) (*ACL, error) { + a, err := C._go_acl_get_file(C.CString(name), t) + if errors.Is(err, syscall.ENODATA) { + err = nil + } + + return newACL(a), err +} + +func (acl *ACL) setFile(name string, t C.acl_type_t) error { + _, err := C._go_acl_set_file(C.CString(name), t, acl.acl) + return err +} + +func newACL(a C.acl_t) *ACL { + acl := &ACL{a} + runtime.SetFinalizer(acl, (*ACL).free) + return acl +} + +type ACL struct { + acl C.acl_t +} + +func (acl *ACL) free() { + C.acl_free(unsafe.Pointer(acl.acl)) + + // no need for a finalizer anymore + runtime.SetFinalizer(acl, nil) +} + +const ( + Read = C.ACL_READ + Write = C.ACL_WRITE + Execute = C.ACL_EXECUTE + + TypeDefault = C.ACL_TYPE_DEFAULT + TypeAccess = C.ACL_TYPE_ACCESS + + UndefinedTag = C.ACL_UNDEFINED_TAG + UserObj = C.ACL_USER_OBJ + User = C.ACL_USER + GroupObj = C.ACL_GROUP_OBJ + Group = C.ACL_GROUP + Mask = C.ACL_MASK + Other = C.ACL_OTHER +) + +type ( + Perm C.acl_perm_t +) + +func (acl *ACL) removeEntry(tt C.acl_tag_t, tq int) error { + var e C.acl_entry_t + + // get first entry + if r, err := C.acl_get_entry(acl.acl, C.ACL_FIRST_ENTRY, &e); err != nil { + return err + } else if r == 0 { + // return on acl with no entries + return nil + } + + for { + if r, err := C.acl_get_entry(acl.acl, C.ACL_NEXT_ENTRY, &e); err != nil { + return err + } else if r == 0 { + // return on drained acl + return nil + } + + var ( + q int + t C.acl_tag_t + ) + + // get current entry tag type + if _, err := C.acl_get_tag_type(e, &t); err != nil { + return err + } + + // get current entry qualifier + if rq, err := C.acl_get_qualifier(e); err != nil { + // neither ACL_USER nor ACL_GROUP + if errors.Is(err, syscall.EINVAL) { + continue + } + + return err + } else { + q = *(*int)(rq) + C.acl_free(rq) + } + + // delete on match + if t == tt && q == tq { + _, err := C.acl_delete_entry(acl.acl, e) + return err + } + } +} + +// Update replaces ACL_USER entry with qualifier uid. +func Update(name string, uid int, perms ...Perm) error { + // read acl from file + a, err := getFile(name, TypeAccess) + if err != nil { + return err + } + // free acl on return if get is successful + defer a.free() + + // remove existing entry + if err = a.removeEntry(User, uid); err != nil { + return err + } + + // create new entry if perms are passed + if len(perms) > 0 { + // create new acl entry + var e C.acl_entry_t + if _, err = C.acl_create_entry(&a.acl, &e); err != nil { + return err + } + + // get perm set of new entry + var p C.acl_permset_t + if _, err = C.acl_get_permset(e, &p); err != nil { + return err + } + + // add target perms + for _, perm := range perms { + if _, err = C.acl_add_perm(p, C.acl_perm_t(perm)); err != nil { + return err + } + } + + // set perm set to new entry + if _, err = C.acl_set_permset(e, p); err != nil { + return err + } + + // set user tag to new entry + if _, err = C.acl_set_tag_type(e, User); err != nil { + return err + } + + // set qualifier (uid) to new entry + if _, err = C.acl_set_qualifier(e, unsafe.Pointer(&uid)); err != nil { + return err } } - return string(s) + + // calculate mask after update + if _, err = C.acl_calc_mask(&a.acl); err != nil { + return err + } + + // write acl to file + return a.setFile(name, TypeAccess) } |