When a zig compiler without LLVM extensions is satisfactory, this
greatly simplified build-from-source process can be used.
This could be useful for users who only want to contribute to the
standard library, for example.
This reverts commit 547481c31c8a538a7badbdce66d81820177ce87f.
There is a comment that did not get addressed with this patch, and the
required test cases are not added.
Reopens#17798.
Addresses a comment in #17779 pointing out the inability to fetch the
upstream BoringSSL sources over Git. The reason for this is because the
Git server used in this case did not include the optional (but
recommended) LF terminator for textual pkt-line data. This commit
adjusts handling of textual pkt-line data so that it works both with and
without the optional trailing LF.
This change fixes some division-by-zero bugs introduced by the optimized
ring buffer read/write functions in d8c067966.
There are edge cases where decompression can use a length zero ring
buffer as the size of the ring buffer used is exactly the the window
size specified by a Zstandard frame, and this can be zero. Switching
away from loops to mem copies means that we need to ensure ring buffers
do not have length zero ring when attempting to read/write from them.
`send_zc` tries to avoid making intermediate copies of data. Zerocopy execution
is not guaranteed and may fall back to copying.
The flags field of the first struct io_uring_cqe may likely contain
IORING_CQE_F_MORE , which means that there will be a second completion event /
notification for the request, with the user_data field set to the same value.
The user must not modify the data buffer until the notification is posted. The
first cqe follows the usual rules and so its res field will contain the number
of bytes sent or a negative error code. The notification's res field will be set
to zero and the flags field will contain IORING_CQE_F_NOTIF. The two step model
is needed because the kernel may hold on to buffers for a long time, e.g.
waiting for a TCP ACK, and having a separate cqe for request completions allows
userspace to push more data without extra delays. Note, notifications are only
responsible for controlling the lifetime of the buffers, and as such don't mean
anything about whether the data has atually been sent out or received by the
other end. Even errored requests may generate a notification, and the user must
check for IORING_CQE_F_MORE rather than relying on the result.
Available since kernel 6.0.
References:
https://man7.org/linux/man-pages/man3/io_uring_prep_send_zc.3.htmlhttps://man7.org/linux/man-pages/man2/io_uring_enter.2.html
Boundary symbols have a special name prefix:
* section$start$segname$sectname
* section$stop$segname$sectname
* segment$start$segname
* segment$stop$segname
and will resolve to either start or end of the respective
section/segment if found.
If not found, we return an error stating we couldn't find the
requested section/segment rather than silently failing and resolving
the address to 0 which seems to be the case with Apple's ld64.
