Most systems (Linux, OpenBSD) adjust 0.5 ms per second, or 0.5 us per
1 ms tick. That is, the clock is sped up or slowed down by at most
0.05%. This means adjusting the clock by 1 s takes 2000 s, and the
clock an be adjusted by at most 1.8 s per hour.
FreeBSD adjusts 5 ms per second if the remaining time adjustment is
>= 1 s (0.5%) , else it adjusts by 0.5 ms as well. This allows adjusting
by (almost) 18 s per hour.
Since Serenity OS can lose more than 22 s per hour (#3429), this
picks an adjustment rate up to 1% for now. This allows us to
adjust up to 36s per hour, which should be sufficient to adjust
the clock fast enough to keep up with how much time the clock
currently loses. Once we have a fancier NTP implementation that can
adjust tick rate in addition to offset, we can think about reducing
this.
adjtime is a bit old-school and most current POSIX-y OSs instead
implement adjtimex/ntp_adjtime, but a) we have to start somewhere
b) ntp_adjtime() is a fairly gnarly API. OpenBSD's adjfreq looks
like it might provide similar functionality with a nicer API. But
before worrying about all this, it's probably a good idea to get
to a place where the kernel APIs are (barely) good enough so that
we can write an ntp service, and once we have that we should write
a way to automatically evaluate how well it keeps the time adjusted,
and only then should we add improvements ot the adjustment mechanism.
When SO_TIMESTAMP is set as an option on a SOCK_DGRAM socket, then
recvmsg() will return a SCM_TIMESTAMP control message that
contains a struct timeval with the system time that was current
when the socket was received.
The implementation only supports a single iovec for now.
Some might say having more than one iovec is the main point of
recvmsg() and sendmsg(), but I'm interested in the control message
bits.
This adds a new header <sys/internals.h>, which provides access to LibC internals.
This is in the interest of type-checking LibC itself, as well as enabling less-hacky
access for uses like LinkDemo.
And, of course, this progresses LibC towards building cleanly with -Wmissing-declarations.
These new syscalls allow you to send and receive file descriptors over
a local domain socket. This will enable various privilege separation
techniques and other good stuff. :^)
pselect() is similar() to select(), but it takes its timeout
as timespec instead of as timeval, and it takes an additional
sigmask parameter.
Change the sys$select parameters to match pselect() and implement
select() in terms of pselect().
And rewrite the timeval functions as inline functions.
Also add the non-standard but fairly common and useful
TIMEVAL_TO_TIMESPEC / TIMESPEC_TO_TIMEVAL functions.
This fixes terminal UI resizing in the vim port. The problem was that
vim had "#ifdef TIOCGWINSZ" around the code that figures out the size
of the terminal.
Since all of our ioctl() requests were enum values, this code was not
compiled into vim at all. This patch fixes that. :^)
.. and make travis run it.
I renamed check-license-headers.sh to check-style.sh and expanded it so
that it now also checks for the presence of "#pragma once" in .h files.
It also checks the presence of a (single) blank line above and below the
"#pragma once" line.
I also added "#pragma once" to all the files that need it: even the ones
we are not check.
I also added/removed blank lines in order to make the script not fail.
I also ran clang-format on the files I modified.
While the compiler provides __SIZE_TYPE__ for declaring size_t,
there's unfortunately no __SSIZE_TYPE__ for ssize_t.
However, we can trick the preprocessor into doing what we want anyway
by doing "#define unsigned signed" before using __SIZE_TYPE__ again.
In f4302b58fb, the kernel-side syscalls (e.g Process::sys$getsockname)
were updated to use SC_get{sock,peer}name_params, but the libc
functions were not updated.
The syscall wrapper for ptrace needs to return the peeked value when
using PT_PEEK.
Because of this, the user has to check errno to detect an error in
PT_PEEK.
This commit changes the actual syscall's interface (only for PT_PEEK) to
allow the syscall wrapper to detect an error and change errno.
PT_SETTREGS sets the regsiters of the traced thread. It can only be
used when the tracee is stopped.
Also, refactor ptrace.
The implementation was getting long and cluttered the alraedy large
Process.cpp file.
This commit moves the bulk of the implementation to Kernel/Ptrace.cpp,
and factors out peek & poke to separate methods of the Process class.
PT_POKE writes a single word to the tracee's address space.
Some caveats:
- If the user requests to write to an address in a read-only region, we
temporarily change the page's protections to allow it.
- If the user requests to write to a region that's backed by a
SharedInodeVMObject, we replace the vmobject with a PrivateIndoeVMObject.
This patch adds a way for a socket to ask to be routed through a
specific interface.
Currently, this option only applies to sending, however, it should also
apply to receiving...somehow :^)
This commit adds a basic implementation of
the ptrace syscall, which allows one process
(the tracer) to control another process (the tracee).
While a process is being traced, it is stopped whenever a signal is
received (other than SIGCONT).
The tracer can start tracing another thread with PT_ATTACH,
which causes the tracee to stop.
From there, the tracer can use PT_CONTINUE
to continue the execution of the tracee,
or use other request codes (which haven't been implemented yet)
to modify the state of the tracee.
Additional request codes are PT_SYSCALL, which causes the tracee to
continue exection but stop at the next entry or exit from a syscall,
and PT_GETREGS which fethces the last saved register set of the tracee
(can be used to inspect syscall arguments and return value).
A special request code is PT_TRACE_ME, which is issued by the tracee
and causes it to stop when it calls execve and wait for the
tracer to attach.
A new IP address or a new network mask can be specified in the command
line arguments of ifconfig to replace the old values of a given network
adapter. Additionally, more information is being printed for each adapter.
Calling shutdown prevents further reads and/or writes on a socket.
We should do a few more things based on the type of socket, but this
initial implementation just puts the basic mechanism in place.
Work towards #428.
sys$waitid() takes an explicit description of whether it's waiting for a single
process with the given PID, all of the children, a group, etc., and returns its
info as a siginfo_t.
It also doesn't automatically imply WEXITED, which clears up the confusion in
the kernel.
