unix++

[G. Ewing]

A few more wild ideas:

* The basis element for name lookups should be

	fd2 = lookup(fd1,pathname_element)

  sort of like the Mac vrefnum/filename concept. Build your own namei()!
  Have fun inventing brave new pathname syntaxes! (Want your system
  to look like MS-DOS? No problem! Edit stdfs.c and relink! :-)

with a standard descriptor STDROOT. (chroot vanishes! Security problem?)

* Someone pointed out #! as an analog of the Mac "creator" concept. But
  the Mac gets by without imposing any conditions on the file contents.
  Perhaps each inode should contain a "creator" link to a file to be
  executed. While we're at it, let's have the kernel open the original
  file on some standard descriptor, to avoid the security problems
  presently associated with setuid #!-files.

* Think of a descriptor has having an "effective mode". Currently this
  includes r and w. Recent proposals would add x to this set. How about
  adding the file's owner and group, and the setuid and setgid bits?
  Then invent a new standard descriptor to hold the "last file executed",
  which inherits these attributes. And now - fsetuid(fd)!!! (Sets the
  process's euid to that of the descriptor, provided it has setuid
  access.) Similarly fsetgid(fd). Combine this with the above
  "creator" mechanism and some interesting possibilities might result.
  Not sure what, yet, need to think hard about this one!

These are just random ideas so far - I may try to come up with a proposal
for a "basis set" of syscalls using these ideas.

Greg Ewing				Internet: greg at cantuar.uucp
Spearnet: greg at nz.ac.cantuar		Telecom: +64 3 667 001 x8357
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Post:	  Computer Science Dept, Univ. of Canterbury, Christchurch, New Zealand
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