On Jun 8,  8:36am, Glenn Cole wrote:
 
> So...what are the implications of using rm? Anything serious? Is this the
> only case where rm may work when :PURGE fails?
>
 
Here are some quotes from the MPE/iX 5.0 Communicator, Chapter 5 "Managing a
5.0
POSIX HP 3000 System":
 
"The rules for purging files need to be understood since MPE now supports
directories and the POSIX unlink() function, which is invoked by the
Shell's rm command.  The MPE PURGE command still FOPENs the target file
and then removes it via FCLOSE(,4).  All security rules apply such that
if the file is already opened, is being STOREd, is allocated, the user
lacks write access, etc., it will not be purged.  If the file has a
lockword then the lockword must be supplied with the filename or it will
be prompted for.  Because PURGE calls FOPEN, individual file access rules
must be obeyed before the file can be deleted, regardless of the access
permissions of the file's parent directory.  PURGE is the most secure way
to delete a file and, even though it accepts POSIX pathnames, it will not
remove directories."
 
"The POSIX unlink() function, and hence the Shell's rm command, are
somewhere in between PURGE and PURGEDIR[ACCT/GROUP] in terms of file
security.  Since unlink() does not open the target object, the object's
individual access rules are ignored and thus unlink() is potentially less
restrictive than PURGE. Also, since the file is not opened, it cannot be
protected by a lockword or unlink() will fail--there is no lockword
prompting."
 
"To unlink a file requires TD access to the entire pathname and DD access
to the file's parent directory, or the equivalent if the file's parent is
an MPE group (see the article "MPE/iX File Access and Security
Enhancements" in this chapter of the Communicator).  Lockworded,
privileged or protected files cannot be unlinked."
 
[Note: TD means Traverse Directory entries, means you have the ability to pass
 through a directory node knowing its name.  DD means Delete Directory entries,
 means you can delete entries in this directory (entries correspond to the
 files and directory names immediately under this directory).]
 
"This implication of PURGE versus rm versus PURGEDIR to system managers is
that PURGE is the preferred way to delete a file.  If that fails then use
the Shell's rm command.  Rm can also to delete directories via the -r
option.  Both PURGE and rm accept wildcards." ...snip...
 
Hope this helps some,
Jeff Vance, MPE Lab
 
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