ENDRUN(4)

💖 ENDRUN(4) 💖

okay so bestie, welcome to the ENDRUN(4) page from the Kernel Interfaces Manual — it's all about the EndRun Technologies native time-of-day message timedelta sensor, and we're gonna make it make sense. ✨

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🌸 NAME 🌸

endrun — the EndRun Technologies native time-of-day message timedelta sensor. literally the whole main-character job of this thing.

🦋 SYNOPSIS 🦋

pseudo-device endrun [count]

💅 DESCRIPTION 💅

so this line discipline? it's the social butterfly that interfaces serial EndRun Technologies devices. no cap. 🫶

the line discipline is enabled by this exact sequence:

#include <sys/ioctl.h>
int ldisc = ENDRUNDISC, fildes; ...
ioctl(fildes, TIOCSETD, &ldisc);

the byte stream is unaltered by the line discipline — she does not touch the data, she just minds her business and maintains a timedelta sensor using the EndRun data. the timedelta sensor will appear as endrun* in the list of sensors, and the delta (in nanoseconds) between the received time information and the local time can be accessed through the sysctl(8) interface. iykyk. 💖

⭐ SENSOR STATES ⭐

the quality of the timedelta is reported as the sensor status, and here's the vibe check:

• OK — the time information is valid. the timedelta is safe to use for applications like ntpd(8). slay. ✅
• WARN — the attached receiver has been indicating a warning condition for at least the last ten minutes. the timedelta should be used with care. lowkey be careful bestie. ⚠️
• CRITICAL — tty timestamping has been turned on but there is no PPS signal present, or the receiver indicated a warning condition for at least the last twenty minutes. check your hardware. like fr fr check it. 🚨

and there's a second sensor whose status is used to report the status of the device itself using the Time Figure Of Merit (TFOM) character:

• OK — the clock is synchronized. TFOM is 6-8. iconic. 👑
• WARN — the clock is synchronized and the time error is greater than 10ms, or the clock is in the unsynchronized state. TFOM is 9. 😬
• CRITICAL — the TFOM is invalid. 💀

🌈 SEE ALSO 🌈

• tty(4)
• ldattach(8)
• ntpd(8)
• sysctl(8)

🎀 HISTORY 🎀

the endrun interface first appeared in OpenBSD 4.6. periodt. 💖

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xoxo, this page is from Debian, dated January 15, 2015, and it's ENDRUN(4) — bye bestie! 💅✨