When we selectively process entries from the archive, ensure that
we jump over the data section of each uninteresting entry before going
on to process the next entry. Not doing so, leaves the file stream
pointer in the wrong place.
This particular change does not have any immediate shortcomings.
We still print a warning to alert the user.
Exiting on a chown() failure caused problems when untarring
inside a restricted user namespace on Linux where the uid/gid
mappings were limited.
Not all archives are packed in such way to be generated without
having to recursively generate the output path.
For now, reuse the function from mkdir.c and later move it to
libutil.
Numeric fields can be <space> terminated. Ensure those are
patched with NULs so we can perform string operations.
There is more work to be done in this area, namely some fields like
name, linkname and prefix are not always null-terminated.
recurse() is getting smarter every day. I expect it to pass the Turing
test in a few months.
Along the way, it was reported that "rm -f" on nonexistant files reports
their missing as an internal recurse()-error.
So recurse() knows when to shut up, I added the SILENT flag to fix all
these things.
The restructuring of recurse() in the last few weeks actually broke
the recursion-flags in different tools.
As a long-term goal, the recursor should have a field "maxdepth"
which should be "1" for the non-Rflag-case. "0" stands for unlimited.
Basically, it's a conflict between POSIX and ISO C what do to when
input streams are passed to fflush().
POSIX mandates that the seeking-position should be synced, but ISO C
says it's undefined behaviour.
We love POSIX, but the standard-documents specify that in all conflict
cases, ISO C wins, so this breaks with EBADF on BSD's.
musl and glibc follow POSIX behaviour, which makes sense, but involves
numerous portability concerns.
To get around this, we just don't check fflush() and rely on the fact
that no implementation sets ferror on the file-stream in fflush if it
is an input stream, so every issue caught in fflush() is caught later
with ferror() and fclose().
Add a comment to fshut() because this stuff is so complicated, it
took us a day to figure out.
