Ok, you have convinced me, as long as the man page and the LTP get fixed.

/Carsten

"Maciej W. Rozycki" wrote:

On Tue, 25 Jun 2002, Carsten Langgaard wrote:

quoted

quoted

Linux platforms do it this way, e.g. Alpha and IA-64.  A SIGSEGV is a
valid response for an invalid address.  Remember you test pipe(3) and not
pipe(2).

I'm not sure that you mean by pipe(2) and pipe(3), but according to my man
page, pipe should return with EFAULT in this case.

 pipe(2) is a syscall, while pipe(3) is a library call (see `man 2 intro'
and `man 3 intro', respectively).  You rarely access syscalls directly --
the system library usually does this for you.  Depending on a system
certain library functions may be trivial syscall wrappers, invoke a number
of syscalls (see e.g. the stat() family) or be implemented entirely in the
userland.

quoted

ERRORS
       EMFILE Too  many  file  descriptors are in use by the pro­
              cess.
       ENFILE The system file table is full.
       EFAULT filedes is not valid.

 Yep, this denotes such an error is possible and under what conditions.  I
don't think it actually mandates it, at least it's not expressed
explicitly.  Anyway, it's valid for i386 and possibly nothing else.  Look
at the system version it refers to -- my version is: "Linux 0.99.11 23
July 1993".

 A brief search of the web for "EFAULT pipe" reveals confirms others agree
with me -- the error is not mandatory (the EFAULT vs SIGSEGV issue was
discussed a few times at least in various contexts -- go search the web).

 I believe a SIGSEGV is saner, too -- this way it's harder for an error
resulting from passing an invalid pointer to remain unnoticed (consider
some code that passes a pointer to read-only memory and fails to check a
result of pipe()).

 If still in doubt, you may try to discuss the LTP result at
[off-list ref].  I don't think anybody wants to rewrite
pipe(2) for all the platforms that handle it our way.

  Maciej

--
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +

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