Mapping the BS2000 standard attributes
The table below shows how the BS2000 standard attributes are mapped to the access rights in POSIX:
BS2000 attributes | POSIX standard ACL | |||||||||
user | group | others | ||||||||
ACCESS | USER-ACCESS | r | w | x | r | w | x | r | w | x |
*READ | *OWNER-ONLY | x | - | x | - | - | - | - | - | - |
*READ | *ALL-USERS/*SPECIAL | x | - | x | x | - | x | x | - | x |
*WRITE | *OWNER-ONLY | x | x | x | - | - | - | - | - | - |
*WRITE | *ALL-USERS/*SPECIAL | x | x | x | x | x | x | x | x | x |
The rights defined with ACCESS and USER-ACCESS are mapped to POSIX access rights for a file only if no Basic Access Control List (BACL) is defined for it.
The following attributes of files and library elements are not mapped to the bs2fs file system:
EXEC-PASSWORD, READ-PASSWORD, WRITE-PASSWORD (file or library element)
EXPIRATION-DATE (file)
GUARD (file or library element)If one of these protection attributes is set for a file or an element, an access attempt can be rejected with EACCES even if the status information supplied seems to permit access.
CODED-CHARACTER-SET (file or library element)
If this attribute is not *NONE, *STD or EDF03IRV, the result of processing in a bs2fs file system can differ from the result of the same processing in BS2000 (for example with the same C program): e.g. different collating sequence, different representation on the screen, etc.
STATE=*IN-HOLD (library element)
If this attribute is set, an access attempt is rejected with EACCES, even though the status information supplied does not enable you to recognize this.
ACCESS-METHOD (library element)
In the case of elements with SOURCE-ATTRIBUTE=*KEEP, this attribute can be adopted by a corresponding file. However, it is ignored in the bs2fs file system. If such an element is copied or moved to a file, processing this file can yield different results from processing the original element.
ISAM key
ISAM keys from BS2000 files are not visible when access takes place via a bs2fs file system. If an ISAM file in a bs2fs file system is copied to another existing ISAM file which is overwritten in the process, the records of the two files then generally have different ISAM keys.
ISAM key (library element)
ISAM keys from an ISAM file which was transferred to a library element using SOURCE-ATTRIBUTE=*KEEP are a component part of the records concerned.
STORAGE-FORM=*DELTA (library element)
Library elements with this attribute (delta elements) can only be read in a bs2fs file system.
Record format B (library element)
Library elements with records with format B can only be edited if they are of type L or of a type derived from this type. Attempts to access elements of a different type are rejected with EMODE.
Record type other than 1 (library element)
Record types with format A and a record type other than 1 are not visible when reading takes place.
In the case of an update (O_RDWR or O_APPEND) and when renaming within the same library and the same type or between types with the same basic type, they are retained provided the source is not open in write mode when renaming takes place.
They are not transferred when a library element is copied or moved into a file or another library or when it is renamed as a type with a different basic type or when a source which is open in write mode is renamed.
BACL attributes
When new bs2fs files and library elements are created and when attributes are modified with chmod, the BACL attributes in BS2000 are enabled. When the BACL is enabled, modifications made using /MODIFY-FILE-ATTRIBUTES are no longer evaluated for USER-ACCESS or ACCESS.
Systems without SECOS:
The BACL group rights of the BS2000 file and the group rights mapped in the bs2fs file system can be modified on systems on which SECOS is not active, but they are not evaluated when files are accessed. Only the user rights and the rights for OTHER count. This behavior is identical in the case of both BS2000 and bs2fs accesses.
Systems with SECOS, *UNIVERSAL group:
On systems on which SECOS is active but no SECOS groups have been configured and assigned, all IDs are members of the *UNIVERSAL group. This has the following consequences:
In the case of file accesses in native BS2000, only the user rights and the rights for GROUP are evaluated, but not the rights for OTHER.
In the case of accesses in the bs2fs file system, the POSIX group and the rights for OTHER play a role:
If the protection attribute
-rw-r----- (0640)is set, read access by another ID is rejected if the ID does not also belong to the same POSIX group. If this is not the case, read permission for OTHER is required to permit access in read mode (0644).If the ID belongs to the same POSIX group, only read permission for GROUP is required.