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perfsonar / owamp

A tool for performing one-way or two-way active measurements
Apache License 2.0
72 stars 31 forks source link

Use adjtimex when ntp_adjtime is not available #81

Closed WorldofJARcraft closed 1 year ago

WorldofJARcraft commented 1 year ago

This is a proposal to solve the same problem as the one addressed by #64 in a backward-compatible way. I have updated configure.ac to check for both ntp_adjtime and adjtimex. If both are found or adjtimex is not found, it uses ntp_adjtime (the current behavior). If only adjtimex is found, it uses adjtimex (workaround for musl, uClibc, etc.). If none are found, compilation behaves as if the sys/timex.h header did not exist and does not use ntp.

mfeit-internet2 commented 1 year ago

Looks sane. I take it you've built and successfully tested this on an adjtimex-only system? (I'll give it a run on regular Linux.)

WorldofJARcraft commented 1 year ago

I did a compile test on the latest release of Alpine Linux, which uses musl libc and has adjtimex but no ntp_adjtime. I also ran owping and owampd using the adjtimex interface and got similar times to what I expected. adjtimex the Linux-specific alternative to ntp_adjtime, and according to its documentation, it behaves exactly the same as ntp_adjtime. The only difference is that the names of the constants allowed for the modes field are different, but that field is set to 0 by memset in time.c. I can run more tests, e.g. with and without ntp synchronization, if you want.