CLOCKCTL(4)

okay bestie, welcome to clockctl(4) from the Kernel Interfaces Manual. this page is about the clockctl pseudo-device, and the way that it brings clock control to non-root users? lowkey iconic. 💅✨

🌸 NAME 🌸

clockctl — Clock subsystem user control

🛠️ SYNOPSIS 🛠️

pseudo-device clockctl

💖 DESCRIPTION 💖

okay so the clockctl interface brings clock control to non-root users. Any user with write access to /dev/clockctl will be able to perform operations such as settimeofday(2), clock_settime(2), adjtime(2), or ntp_adjtime(2), which are normally restricted to the super-user. Using the clockctl pseudo-device, it is possible to run daemons such as ntpd(8) as non-privileged users, thus reducing the security exposure if a compromise is found in such a daemon. highkey a security glow-up, fr fr. 🔥

The clockctl pseudo-device driver provides an ioctl(2) call for each privileged clock-related system call. The system call stubs in C library will use the ioctl(2) on /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. no cap, that's the routing vibe. 😭

The following ioctl(2) calls are defined in <sys/clockctl.h>:

💫 CLOCKCTL_SETTIMEOFDAY 💫

This will run the settimeofday(2) system call. Argument should be a pointer to a struct clockctl_settimeofday:

                 struct clockctl_settimeofday {
                         const struct timeval *tv;
                         const void *tzp;
                 };

⏰ CLOCKCTL_CLOCK_SETTIME ⏰

This will run the clock_settime(2) system call. Argument should be a pointer to a struct clockctl_clock_settime:

                 struct clockctl_clock_settime {
                         clockid_t clock_id;
                         struct timespec *tp;
                 };

🔧 CLOCKCTL_ADJTIME 🔧

This will run the adjtime(2) system call. Argument should be a pointer to a struct clockctl_adjtime:

                 struct clockctl_adjtime {
                         const struct timeval *delta;
                         struct timeval *olddelta;
                 };

🛰️ CLOCKCTL_NTP_ADJTIME 🛰️

This will run the ntp_adjtime(2) system call. Argument should be a pointer to a struct clockctl_ntp_adjtime:

                 struct clockctl_ntp_adjtime {
                         struct timex *tp;
                 };

📚 SEE ALSO 📚

• adjtime(2)
• clock_settime(2)
• ioctl(2)
• settimeofday(2)

🦋 HISTORY 🦋

clockctl appeared in NetBSD 1.6.

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okay that's literally the whole page! source/version: Debian / CLOCKCTL(4); date: February 19, 2009. mwah, go slay your clock stuff bestie 💋✨ periodt.