[PATCH] test-genzeros: avoid raw write(2)
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Feb 16, 2023, 02:56 UTC
- Message-ID
- <xmqqo7putj1t.fsf_-_@gitster.g>
- In-Reply-To
- <xmqqwn4itmb1.fsf@gitster.g>
This test helper feeds 256kB of data at once to a single invocation of the write(2) system call, which may be too much for some platforms.
Call our xwrite() wrapper that knows to honor MAX_IO_SIZE limit and cope with short writes due to EINTR instead, and die a bit more loudly by calling die_errno() when xwrite() indicates an error.
Reported-by: Randall S. Becker <rsbecker@nexbridge.com> Helped-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com> ---
Junio C Hamano <gitster@pobox.com> writes:
> Jeff King <peff@peff.net> writes:
>
>> So yeah, this seems like an obvious good fix. Using write_or_die() might
>> be even better, as it would report errors rather than quietly returning
>> non-zero.
>
> Maybe. Let me cook up a version with a proposed log message. I ended up avoiding write_or_die() primarily because there is
nothing "Git" about this helper, which is a poor-man's emulation
of "dd if=/dev/zero". It felt a bit too much to pull cache.h in
as dependency for it.t/helper/test-genzeros.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/t/helper/test-genzeros.c b/t/helper/test-genzeros.c index 8ca988d621..47af843b68 100644 --- a/t/helper/test-genzeros.c +++ b/t/helper/test-genzeros.c @@ -17,15 +17,16 @@ int cmd__genzeros(int argc, const char **argv) /* Writing out individual NUL bytes is slow... */ while (count < 0) - if (write(1, zeros, ARRAY_SIZE(zeros)) < 0) - return -1; + if (xwrite(1, zeros, ARRAY_SIZE(zeros)) < 0) + die_errno("write error"); while (count > 0) { - n = write(1, zeros, count < ARRAY_SIZE(zeros) ? - count : ARRAY_SIZE(zeros)); + n = xwrite(1, zeros, + count < ARRAY_SIZE(zeros) + ? count : ARRAY_SIZE(zeros)); if (n < 0) - return -1; + die_errno("write error"); count -= n; }
-- 2.39.2-501-gd9d677b2d8