Much like the existing in6addr_any global and the IN6ADDR_ANY_INIT
macro, our LibC is also expected to export the in6addr_loopback global
and the IN6ADDR_LOOPBACK_INIT constant.
These were found by the stress-ng port.
This feature was introduced in version 4.17 of the Linux kernel, and
while it's not specified by POSIX, I think it will be a nice addition to
our system.
MAP_FIXED_NOREPLACE provides a less error-prone alternative to
MAP_FIXED: while regular fixed mappings would cause any intersecting
ranges to be unmapped, MAP_FIXED_NOREPLACE returns EEXIST instead. This
ensures that we don't corrupt our process's address space if something
is already at the requested address.
Note that the more portable way to do this is to use regular
MAP_ANONYMOUS, and check afterwards whether the returned address matches
what we wanted. This, however, has a large performance impact on
programs like Wine which try to reserve large portions of the address
space at once, as the non-matching addresses have to be unmapped
separately.
Add the `posix_madvise(..)` LibC implementation that just forwards
to the normal `madvise(..)` implementation.
Also define a few POSIX_MADV_DONTNEED and POSIX_MADV_NORMAL as they
are part of the POSIX API for `posix_madvise(..)`.
This is needed by the `fio` port.
These 2 members are required by POSIX and are also used by some ports.
Zero is a valid value for both of these, so no further work to support
them is required.
The sa_family field in SIOCGIFHWADDR specifies the underlying network
interface's device type, this is hardcoded to generic "Ethernet" right
now, as we don't have a nice way to query it.
Not much to say here, this is an implementation of this call that
accesses the actual limit constant that's used by the VirtualFileSystem
class.
As a side note, this is required for my eventual Qt port.
This fixes at least half of our LibC includes in the kernel. The source
of truth for errno codes and their description strings now lives in
Kernel/API/POSIX/errno.h as an enumeration, which LibC includes.
The advices are almost always exclusive of one another, and while POSIX
does not define madvise, most other unix-like and *BSD systems also only
accept a singular value per call.
This allows userspace to trigger a full (FIXME) flush of a shared file
mapping to disk. We iterate over all the mapped pages in the VMObject
and write them out to the underlying inode, one by one. This is rather
naive, and there's lots of room for improvement.
Note that shared file mappings are currently not possible since mmap()
returns ENOTSUP for PROT_WRITE+MAP_SHARED. That restriction will be
removed in a subsequent commit. :^)
Looking at how these two constants are commonly used in other systems,
we should be able to mimic their behavior using our PT_PEEK constant.
For example, see:
https://man.netbsd.org/NetBSD-6.0.1/i386/ptrace.2
