String&& is just not very practical. Also return const String& when the
returned string is a member variable. The call site is free to make a copy
if he wants, but otherwise we can avoid the retain count churn.
After reading a bunch of POSIX specs, I've learned that a file descriptor
is the number that refers to a file description, not the description itself.
So this patch renames FileDescriptor to FileDescription, and Process now has
FileDescription* file_description(int fd).
Define the multiboot info struct properly so we don't have to grab at byte
offsets in the memory access checker code. Also print kernel command line
in init().
We definitely need to replace m_executable before clearing interrupts, since
otherwise we might call ~Custody() which would make it assert in locking.
Also avoid calling FileDescriptor::metadata() repeatedly and just cache the
result from the first call.
I also added a comment at the point where we've decided to commit to the new
executable and follow through with the swap.
The current working directory is now stored as a custody. Likewise for a
process executable file. This unbreaks /proc/PID/fd which has not been
working since we made the filesystem bigger.
This still needs a bunch of work, for instance when renaming or removing
a file somewhere, we have to update the relevant custody links.
Right now, we allow anything inside a user to raise or lower any other process's
priority. This feels simple enough to me. Linux disallows raising, but
that's annoying in practice.
By moving the sending (and receiving) thread into the BlockedSignal state,
we ensure that the thread doesn't continue executing until the signal
has been dispatched.
This is in preparation for eventually using it in userspace.
LinearAddress.h has not been moved for the time being (as it seems to be
only used by a very small part of the code).
Since we transition to a new PageDirectory on exec(), we need a matching
RangeAllocator to go with the new directory. Instead of juggling this in
Process and MemoryManager, simply attach the RangeAllocator to the
PageDirectory instead.
Fixes#61.
Passing this flag to recv() temporarily puts the file descriptor into
non-blocking mode.
Also implement LocalSocket::recv() as a simple forwarding to read().
select essentially has 3 modes (which is presumably why we're finding it
so hard to get this right in a reliable way :)).
1. NULL timeout -- no timeout on blocking
2. non-NULL timeout that is not zero'd -- timeout on blocking
3. non-NULL but zero timeout -- no blocking at all (immediate poll)
For cases 1 and 2, we want to block the thread. We have a timeout set
only for case 2, though.
Case 3 should not block the thread, and does not have a timeout set.
The scheduler expects m_select_timeout to act as a deadline. That is, it
should contain the time that a task should wake at -- but we were
directly copying the time from userspace, which meant that it always
returned virtually immediately.
At the same time, fix CEventLoop to not rely on the broken select behavior
by subtracting the current time from the time of the nearest timer.
