| GENFS_CAN_ACCESS(9) | Kernel Developer's Manual | GENFS_CAN_ACCESS(9) | 
genfs_can_access —
#include <miscfs/genfs/genfs.h>
int
  
  genfs_can_access(vnode_t *vp,
    kauth_cred_t cred, uid_t
    file_uid, gid_t file_gid, mode_t
    file_mode, struct acl *acl,
    accmode_t accmode);
This call is intended to support implementations of
    VOP_ACCESS(9), which will
    use their own access methods to retrieve the vnode properties, and then
    invoke vaccess() in order to perform the actual
    check. Implementations of
    VOP_ACCESS(9) may choose
    to implement additional security mechanisms whose results will be composed
    with the return value.
The algorithm used by genfs_can_access()
    selects a component of the file permission bits based on comparing the
    passed credential, file owner, and file group. If the credential's effective
    UID matches the file owner, then the owner component of the permission bits
    is selected. If the UID does not match, then the credential's effective GID,
    followed by additional groups, are compared with the file group—if
    there is a match, then the group component of the permission bits is
    selected. If neither the credential UID or GIDs match the passed file owner
    and group, then the other component of the permission bits is selected.
Once appropriate protections are selected for the current credential, the requested access mode, in combination with the vnode type, will be compared with the discretionary rights available for the credential. If the rights granted by discretionary protections are insufficient, then super-user privilege, if available for the credential, will also be considered.
genfs_can_access() will return 0 on success, or a
  non-zero error value on failure.
vaccess() were written by Robert
  Watson.
| January 17, 2022 | NetBSD 10.0 |