As reported in bug 23675 and shown up in the recently added tests of
different cases of freopen (relevant part of the test currently
conditioned under #if 0 to avoid a failure resulting from this bug),
freopen wrongly forces the stream to unoriented even when a mode with
,ccs= is specified, though such a mode is supposed to result in a
wide-oriented stream. Move the clearing of _mode to before the actual
reopening occurs, so that the main fopen implementation can leave a
wide-oriented stream in the ,ccs= case.
Tested for x86_64.
As reported in bug 32134, freopen does not clear the flags set in
fp->_flags2 by the "e", "m" or "c" mode characters. Clear these so
that they can be set or not as appropriate from the mode string passed
to freopen. The relevant test for "e" in tst-freopen2-main.c is
enabled accordingly; "c" is expected to be covered in a separately
written test (and while tst-freopen2-main.c does include transitions
to and from "m", that's not really a semantic flag intended to result
in behaving in an observably different way).
Tested for x86_64.
freopen is rather minimally tested in libio/tst-freopen and
libio/test-freopen. Add some more thorough tests, covering different
cases for change of mode in particular. The tests are run for both
freopen and freopen64 (given that those functions have two separate
copies of much of the code, so any bug fix directly in the freopen
code would probably need applying in both places).
Note that there are two parts of the tests disabled because of bugs
discovered through running the tests, with bug numbers given in
comments. I expect to address those separately. The tests also don't
cover changes to cancellation ("c" in mode); I think that will better
be handled through a separate test. Also to handle separately:
testing on stdin / stdout / stderr; documenting lack of support for
streams opened with popen / fmemopen / open_memstream / fopencookie;
maybe also a chroot test without /proc; maybe also more thorough tests
for large file handling on 32-bit systems (freopen64).
Tested for x86_64.
