Remove driver functions based on adjtime() and switch to the new timex
driver. The kernel allows the timex frequency to be set in the full
range of int32_t, which gives a maximum frequency of 32768 ppm. Round
the limit to 32500 ppm.
- a feature test macro is needed to get msg_control in struct msghdr
- variables must not be named sun to avoid conflict with a macro
- res_init() needs -lresolv
- configure tests for IPv6 and getaddrinfo need -lsocket -lnsl
- pid_t is defined as long and needs to be cast for %d format
Check if the C compiler works to get a useful error message when it
doesn't or it's missing. If the CC environment variable is not set, try
gcc and then cc.
Switch from the SunOS adjtime() based driver to the timex driver.
There is no FreeBSD-specific code, so call SYS_Timex_Initialise()
and SYS_Timex_Finalise() directly from sys.c.
Remove the driver functions based on adjtime() and switch to the new
timex driver, which is based on ntp_adjtime(). This allows chronyd to
control the kernel frequency, adjust the offset with sub-microsecond
accuracy, and set the kernel leap and sync status. A drawback is that
the maximum slew rate is now limited by the 500 ppm maximum frequency
offset, while adjtime() on NetBSD slewed by up to 5000 ppm.
Remove functions that are included in the new timex driver. Keep only
functions that have extended functionality, i.e. read and set the
frequency using the timex tick field and apply step offset with
ADJ_SETOFFSET.
Merge the code from wrap_adjtimex.c that is still needed with
sys_linux.c and remove the file.
The Linux secure computing (seccomp) facility allows a process to
install a filter in the kernel that will allow only specific system
calls to be made. The process is killed when trying to make other system
calls. This is useful to reduce the kernel attack surface and possibly
prevent kernel exploits when the process is compromised.
Use the libseccomp library to add rules and load the filter into the
kernel. Keep a list of system calls that are always allowed after
chronyd is initialized. Restrict arguments that may be passed to the
socket(), setsockopt(), fcntl(), and ioctl() system calls. Arguments
to socketcall(), which is used on some architectures as a multiplexer
instead of separate socket system calls, are not restricted for now.
The mailonchange directive is not allowed as it calls sendmail.
Calls made by the libraries that chronyd is using have to be covered
too. It's difficult to determine which system calls they need as it may
change after an upgrade and it may depend on their configuration (e.g.
resolver in libc). There are also differences between architectures. It
can all break very easily and is therefore disabled by default. It can
be enabled with the new -F option.
This is based on a patch from Andrew Griffiths <agriffit@redhat.com>.
On NetBSD programs with write access to /dev/clockctl can adjust or set
the system clock without the root privileges. Add a function to drop the
privileges and check if the process has write access to the device to
get a more descriptive error message when the chrony uid/gid doesn't
match the owner of the device.
NTP timestamps use only 32 bits to count seconds and the current NTP era
ends in 2036. Add support for converting NTP timestamps from other NTP
eras on systems with 64-bit time_t.
The earliest assumed NTP time is set by the configure script (by default
to 50 years before the date of the build) and earlier NTP timestamps
underflow to the following NTP era.
Strip all slewing code (adjtime(), freq locked nano PLL, fast tick
slewing) from the Linux driver and use the new generic frequency only
slewing instead. The advantages include stable clock control with very
short update intervals, good control of the slewing frequency, cheap
cooking of raw time stamps and unlimited frequency offset.
Run getaddrinfo()/gethostbyname() in separate thread to avoid blocking.
Only one resolving thread is running at one time, so this should work
also on systems where the functions are not thread-safe.
Add new DEBUG_LOG macro for debug messages. The messages are enabled
when compiled with --enable-debug and they are printed when the -d
option is used twice.
Implement a driver which allows using PTP hardware clock (PHC) as a
reference clock. It uses the PTP_SYS_OFFSET ioctl or clock_gettime()
to measure the offset between the PTP clock and the system clock. Ten
readings are made for every driver poll and the fastest one is returned.
As PHCs are typically kept in TAI instead of UTC, it's necessary to set
the TAI/UTC offset manually by the offset option. This could be improved
by obtaining the offset automatically from the right/UTC timezone.
