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GENFS(9) Kernel Developer's Manual GENFS(9)

genfs — genfs routines

#include <miscfs/genfs/genfs.h>

int
genfs_can_access(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid, mode_t acc_mode, kauth_cred_t cred);

int
genfs_can_chflags(kauth_cred_t cred, enum vtype type, uid_t owner_uid, bool changing_sysflags);

int
genfs_can_chmod(enum vtype type, kauth_cred_t cred, uid_t cur_uid, gid_t cur_gid, mode_t new_mode);

int
genfs_can_chown(kauth_cred_t cred, uid_t cur_uid, gid_t cur_gid, uid_t new_uid, gid_t new_gid);

int
genfs_can_chtimes(vnode_t *vp, u_int vaflags, uid_t owner_uid, kauth_cred_t cred);

int
genfs_can_extattr(kauth_cred_t cred, int access_mode, vnode_t *vp, const char *attr);

int
genfs_can_sticky(kauth_cred_t cred, uid_t dir_uid, uid_t file_uid);

The functions documented here are general routines for internal use in file systems to implement common policies for performing various operations. The developer must understand that these routines implement no system-wide policies and only take into account the object being accessed and the nominal values of the credentials accessing it.

In other words, these functions are not meant to be called directly. They are intended to be used in kauth(9) vnode scope authorization calls, for providing the fall-back file system decision.

As a rule of thumb, code that looks like this is wrong:

error = genfs_can_foo(...); /* WRONG */

While code that looks like this is right:

error = kauth_authorize_vnode(..., genfs_can_foo(...));

(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid, mode_t acc_mode, kauth_cred_t cred)
Implements file access checking based on traditional Unix permissions.
(kauth_cred_t cred, enum vtype type, uid_t owner_uid, bool changing_sysflags)
Implements chflags(2) policy.
(enum vtype type, kauth_cred_t cred, uid_t cur_uid, gid_t cur_gid, mode_t new_mode)
Implements chmod(2) policy.
(kauth_cred_t cred, uid_t cur_uid, gid_t cur_gid, uid_t new_uid, gid_t new_gid)
Implements chown(2) policy.
(vnode_t *vp, u_int vaflags, uid_t owner_uid, kauth_cred_t cred)
Implements utimes(2) policy.
(kauth_cred_t cred, int access_mode, vnode_t *vp, const char *attr)
Implements extended attributes access policy.
(kauth_cred_t cred, uid_t dir_uid, uid_t file_uid)
Implements rename and delete policy from sticky directories.

kauth(9)

Elad Efrat <elad@NetBSD.org> wrote this manual page.

March 1, 2012 NetBSD-9.2