Open System Services Programmer's Guide

OSS ACLs and NFS Clients
OSS ACLs are not supported by the OSS Network File System (NFS) for J06.08 and earlier J-series
RVUs, H06.19 and earlier H-series RVUs, or G-series RVUs. Any attempt by NFS clients to access
OSS objects protected by OSS ACLs that contain optional ACL entries is denied.
OSS ACLs are supported by the OSS NFS for J06.09 and later J-series RVUs and H06.20 and
later H-series RVUs as follows:
• Access by the OSS Network File System (NFS) to OSS objects protected by OSS ACLs that
contain optional ACL entries can be allowed, depending upon the NFSPERMMAP attribute
value for the fileset that contains the object.
• The NFSPERMMAP attribute value selects the algorithm used to map the OSS ACL permissions
for the object to the standard permissions (rwxrwxrwx) expected for the object by NFS V2
clients.
• The default value for the NFSPERMMAP attribute, DISABLED, specifies that any attempt by
NFS clients to access OSS objects protected by OSS ACLs that contain optional ACL entries
is denied. This behavior matches the behavior for J06.08 and earlier J-series RVUs, H06.19
and earlier H-series RVUs, and G-series RVUs.
For a detailed description of OSS ACLs, including examples, see the acl(5) reference page
either online or in the Miscellaneous Topics section of the Open System Services System Calls
Reference Manual. For information about the NFSPERMMAP attribute, see the Open System Services
Management and Operations Guide. For more information about OSS NFS file system security,
see the Overview of NFS for Open System Services and the Open System Services NFS Management
and Operations Guide.
Accessible Files
All OSS source and text files are odd-unstructured files. Files in the /G directory that are used as
OSS source or text files are Guardian file type 180. Files in the OSS environment are Guardian
file type 100 regardless of content. These files permit reading and writing of both even and odd
byte counts and positioning to both even and odd byte addresses. Unstructured files do not have
a built-in record structure.
Only odd-unstructured files can be read and written in the OSS environment. EDIT files (file type
101) are unstructured but not odd-unstructured, and they can be opened only for reading in the
OSS environment. All other Guardian files are inaccessible from the OSS file system but can be
accessed through Guardian file-system procedures.
On H-series RVUs prior to H06.06 and on G-series RVUs prior to G06.29, OSS files had a size
limit of approximately 2 GB (GB), and an underlying Guardian file of Format 1 (the file format
was normally not visible to customer applications). For J-series RVUs, H06.06 and later RVUs, and
G06.29 and later G-series RVUs, OSS files larger than approximately 2 GB are supported, and
can have an underlying Guardian file of either Format 1 or Format 2 (see “Accessing OSS Files
Larger Than 2 GB” (page 78)).
Using the ANSISTREAMS Pragma (Guardian C Program)
The ANSISTREAMS pragma in a Guardian C program causes your application’s standard input
(stdin), standard output (stdout), and standard error (stderr) files to be opened as
odd-unstructured disk files with no line length limit. Without this pragma these files are opened as
EDIT files with a line length limit of 239 characters. The ANSISTREAMS pragma enables your
programs to comply with the ISO/ANSI C standard, which requires that the C compiler support
lines containing at least 254 characters including the terminating newline character.
If the SYSTYPE OSS pragma is set (the default setting for the c89 and c99 utilities), you do not
need to specify the ANSISTREAMS pragma because it is set automatically.
For further information about the ANSISTREAMS pragma, refer to the C/C++ Programmer’s Guide.
64 Managing Files