Copyright (c) 2001 The NetBSD Foundation, Inc.
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.Dd October 20, 2001 .Dt CLOCKCTL 4 .Os .Sh NAME .Nm clockctl .Nd Clock subsystem user control .Sh SYNOPSIS .Cd pseudo-device clockctl .Sh DESCRIPTION The .Nm interface brings clock control to non-root users. Any user with write access to
a /dev/clockctl will be able to perform operations such as .Xr settimeofday 2 , .Xr clock_settime 2 , .Xr adjtime 2 , or .Xr ntp_adjtime 2 , which are normally restricted to the super-user. Using the .Nm pseudo-device, it is possible to run daemons such as .Xr ntpd 8 as non-privileged users, thus reducing the security exposure if a compromise is found in such a daemon.
p The .Nm pseudo-device driver provides an .Xr ioctl 2 call for each privileged clock-related system call. The system call stubs in C library will use the .Xr ioctl 2 on
a /dev/clockctl if the special file is present and accessible, or will revert to the plain super-user-restricted system call if the special file is not accessible.
p The following .Xr ioctl 2 calls are defined in .Aq Pa sys/clockctl.h : l -tag -width CLOCKCTL t Dv CLOCKCTL_SETTIMEOFDAY This will run the .Xr settimeofday 2 system call. Argument should be a pointer to a .Va struct clockctl_settimeofday_args : d -literal struct clockctl_settimeofday_args { struct timeval tv; struct timezone tzp; }; .Ed t Dv CLOCKCTL_CLOCK_SETTIME This will run the .Xr clock_settime 2 system call. Argument should be a pointer to a .Va struct clockctl_clock_settime_args : d -literal struct clockctl_clock_settime_args { clockid_t clock_id; struct timespec tp; }; .Ed t Dv CLOCKCTL_ADJTIME This will run the .Xr adjtime 2 system call. Argument should be a pointer to a .Va struct clockctl_adjtime_args : d -literal struct clockctl_adjtime_args { struct timeval delta; struct timeval olddelta; }; .Ed t Dv CLOCKCTL_NTP_ADJTIME This will run the .Xr ntp_adjtime 2 system call. Argument should be a pointer to a .Va struct clockctl_ntp_adjtime_args : d -literal struct clockctl_ntp_adjtime_args { struct timex tp; }; .Ed .El .Sh SEE ALSO .Xr adjtime 2 , .Xr clock_settime 2 , .Xr ioctl 2 , .Xr settimeofday 2 .Sh HISTORY .Nm appeared in .Nx 1.6 .