Some distros provide SHA1 collision-detect code as a shared library.
It's the same code as we have in git tree (but may be with a different
init default for hash), and git can link with it as well; at least, it
may make maintenance easier, according to our security guys.
This patch allows user to build git linking with the external sha1dc
library instead of the built-in code. User needs to define
DC_SHA1_EXTERNAL explicitly. As default without it, the built-in
sha1dc code is used like before.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The plumbing code between sha1dc and git is defined in
sha1dc_git.[ch], but these aren't compiled / included directly but
only via the indirect inclusion from sha1dc code. This is slightly
confusing when you try to trace the build flow.
This patch brings the following changes for simplification:
- Make sha1dc_git.c stand-alone and build from Makefile
- sha1dc_git.h is the common header to include further sha1.h
depending on the build condition
- Move comments for plumbing codes from the header to definitions
This is also meant as a preliminary work for further plumbing with
external sha1dc shlib.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update sha1dc from the latest version by the upstream
maintainer[1].
This version includes a commit of mine which allows for replacing the
local modifications done to the upstream files in git.git with macro
definitions to monkeypatch it in place.
It also brings in a change[2] upstream made for the breakage 2.13.0
introduced on SPARC and other platforms that forbid unaligned
access[3].
This means that the code customizations done since the initial import
in commit 28dc98e343 ("sha1dc: add collision-detecting sha1
implementation", 2017-03-16) can be done purely via Makefile
definitions and by including the content of our own sha1dc_git.[ch] in
sha1dc/sha1.c via a macro.
1. cc465543b3
2. 33a694a9ee
3. "Git 2.13.0 segfaults on Solaris SPARC due to DC_SHA1=YesPlease
being on by default"
(https://public-inbox.org/git/CACBZZX6nmKK8af0-UpjCKWV4R+hV-uk2xWXVA5U+_UQ3VXU03g@mail.gmail.com/)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
