musl - Question about musl's time() implementation in time.c

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Message-ID: <CAFJhRnoEifeo0Tr2qfKD031C=9jYZ7oP3zSR9hFUmFp86Og7+Q@mail.gmail.com>
Date: Tue, 7 Jun 2022 15:25:13 +0300
From: Zev Levy Stevenson <zevlevys@...il.com>
To: musl@...ts.openwall.com
Subject: Question about musl's time() implementation in time.c

Hi all,

While running the libc-test test suite on a customized clang+musl build, I
had trouble with some of the tests because of issues with time accuracy.
I can go in detail if needed, but the problem seemed to boil down to the
time() function in musl (in src/time/time.c) using a clock_gettime syscall
(without vdso) instead of using the Linux time syscall that we expected it
to use. Some other libc implementations use this syscall, and indeed after
switching the syscall used in time () the tests passed, seemingly because
the accuracy of the clocks used matched up.
My main question is why musl's implementation doesn't use the time syscall,
I'd be happy to hear if there was a special reason for this.

Thanks, Zev

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