Commit Graph

445 Commits

Author SHA1 Message Date
Jacob Vosmaer
55a9651d26 upload-pack.c: increase output buffer size
When serving a fetch, git upload-pack copies data from a git
pack-objects stdout pipe to its stdout. This commit increases the size
of the buffer used for that copying from 8192 to 65515, the maximum
sideband-64k packet size.

Previously, this buffer was allocated on the stack. Because the new
buffer size is nearly 64KB, we switch this to a heap allocation.

On GitLab.com we use GitLab's pack-objects cache which does writes of
65515 bytes. Because of the default 8KB buffer size, propagating these
cache writes requires 8 pipe reads and 8 pipe writes from
git-upload-pack, and 8 pipe reads from Gitaly (our Git RPC service).
If we increase the size of the buffer to the maximum Git packet size,
we need only 1 pipe read and 1 pipe write in git-upload-pack, and 1
pipe read in Gitaly to transfer the same amount of data. In benchmarks
with a pure fetch and 100% cache hit rate workload we are seeing CPU
utilization reductions of over 30%.

Signed-off-by: Jacob Vosmaer <jacob@gitlab.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-15 11:51:18 -08:00
Ævar Arnfjörð Bjarmason
2b7098936c run-command API users: use strvec_pushl(), not argv construction
Change a pattern of hardcoding an "argv" array size, populating it and
assigning to the "argv" member of "struct child_process" to instead
use "strvec_pushl()" to add data to the "args" member.

This implements the same behavior as before in fewer lines of code,
and moves us further towards being able to remove the "argv" member in
a subsequent commit.

Since we've entirely removed the "argv" variable(s) we can be sure
that no potential logic errors of the type discussed in a preceding
commit are being introduced here, i.e. ones where the local "argv" was
being modified after the assignment to "struct child_process"'s
"argv".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-25 22:15:07 -08:00
Junio C Hamano
5331af2352 Merge branch 'ab/serve-cleanup'
Code clean-up around "git serve".

* ab/serve-cleanup:
  upload-pack: document and rename --advertise-refs
  serve.[ch]: remove "serve_options", split up --advertise-refs code
  {upload,receive}-pack tests: add --advertise-refs tests
  serve.c: move version line to advertise_capabilities()
  serve: move transfer.advertiseSID check into session_id_advertise()
  serve.[ch]: don't pass "struct strvec *keys" to commands
  serve: use designated initializers
  transport: use designated initializers
  transport: rename "fetch" in transport_vtable to "fetch_refs"
  serve: mark has_capability() as static
2021-09-20 15:20:43 -07:00
Junio C Hamano
c2509c5407 Merge branch 'jv/pkt-line-batch'
Reduce number of write(2) system calls while sending the
ref advertisement.

* jv/pkt-line-batch:
  upload-pack: use stdio in send_ref callbacks
  pkt-line: add stdio packet write functions
2021-09-20 15:20:41 -07:00
Jacob Vosmaer
70afef5cdf upload-pack: use stdio in send_ref callbacks
In both protocol v0 and v2, upload-pack writes one pktline packet per
advertised ref to stdout. That means one or two write(2) syscalls per
ref. This is problematic if these writes become network sends with
high overhead.

This commit changes both send_ref callbacks to use buffered IO using
stdio.

To give an example of the impact: I set up a single-threaded loop that
calls ls-remote (with HTTP and protocol v2) on a local GitLab
instance, on a repository with 11K refs. When I switch from Git
v2.32.0 to this patch, I see a 40% reduction in CPU time for Git, and
65% for Gitaly (GitLab's Git RPC service).

So using buffered IO not only saves syscalls in upload-pack, it also
saves time in things that consume upload-pack's output.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Jacob Vosmaer <jacob@gitlab.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-01 10:20:39 -07:00
Kim Altintop
3955140653 upload-pack.c: treat want-ref relative to namespace
When 'upload-pack' runs within the context of a git namespace, treat any
'want-ref' lines the client sends as relative to that namespace.

Also check if the wanted ref is hidden via 'hideRefs'. If it is hidden,
respond with an error as if the ref didn't exist.

Helped-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Kim Altintop <kim@eagain.st>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-01 07:54:18 -07:00
Ævar Arnfjörð Bjarmason
f234da8019 serve.[ch]: remove "serve_options", split up --advertise-refs code
The "advertise capabilities" mode of serve.c added in
ed10cb952d (serve: introduce git-serve, 2018-03-15) is only used by
the http-backend.c to call {upload,receive}-pack with the
--advertise-refs parameter. See 42526b478e (Add stateless RPC options
to upload-pack, receive-pack, 2009-10-30).

Let's just make cmd_upload_pack() take the two (v2) or three (v2)
parameters the the v2/v1 servicing functions need directly, and pass
those in via the function signature. The logic of whether daemon mode
is implied by the timeout belongs in the v1 function (only used
there).

Once we split up the "advertise v2 refs" from "serve v2 request" it
becomes clear that v2 never cared about those in combination. The only
time it mattered was for v1 to emit its ref advertisement, in that
case we wanted to emit the smart-http-only "no-done" capability.

Since we only do that in the --advertise-refs codepath let's just have
it set "do_done" itself in v1's upload_pack() just before send_ref(),
at that point --advertise-refs and --stateless-rpc in combination are
redundant (the only user is get_info_refs() in http-backend.c), so we
can just pass in --advertise-refs only.

Since we need to touch all the serve() and advertise_capabilities()
codepaths let's rename them to less clever and obvious names, it's
been suggested numerous times, the latest of which is [1]'s suggestion
for protocol_v2_serve_loop(). Let's go with that.

1. https://lore.kernel.org/git/CAFQ2z_NyGb8rju5CKzmo6KhZXD0Dp21u-BbyCb2aNxLEoSPRJw@mail.gmail.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-05 08:59:37 -07:00
Ævar Arnfjörð Bjarmason
28a592e4f4 serve.[ch]: don't pass "struct strvec *keys" to commands
The serve.c API added in ed10cb952d (serve: introduce git-serve,
2018-03-15) was passing in the raw capabilities "keys", but nothing
downstream of it ever used them.

Let's remove that code because it's not needed. If we do end up
needing to pass information about the advertisement in the future
it'll make more sense to have serve.c parse the capabilities keys and
pass the result of its parsing, rather than expecting expecting its
API users to parse the same keys again.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-05 08:59:37 -07:00
Junio C Hamano
644f4a2046 Merge branch 'jt/push-negotiation'
"git push" learns to discover common ancestor with the receiving
end over protocol v2.

* jt/push-negotiation:
  send-pack: support push negotiation
  fetch: teach independent negotiation (no packfile)
  fetch-pack: refactor command and capability write
  fetch-pack: refactor add_haves()
  fetch-pack: refactor process_acks()
2021-05-16 21:05:22 +09:00
Jonathan Tan
9c1e657a8f fetch: teach independent negotiation (no packfile)
Currently, the packfile negotiation step within a Git fetch cannot be
done independent of sending the packfile, even though there is at least
one application wherein this is useful. Therefore, make it possible for
this negotiation step to be done independently. A subsequent commit will
use this for one such application - push negotiation.

This feature is for protocol v2 only. (An implementation for protocol v0
would require a separate implementation in the fetch, transport, and
transport helper code.)

In the protocol, the main hindrance towards independent negotiation is
that the server can unilaterally decide to send the packfile. This is
solved by a "wait-for-done" argument: the server will then wait for the
client to say "done". In practice, the client will never say it; instead
it will cease requests once it is satisfied.

In the client, the main change lies in the transport and transport
helper code. fetch_refs_via_pack() performs everything needed - protocol
version and capability checks, and the negotiation itself.

There are 2 code paths that do not go through fetch_refs_via_pack() that
needed to be individually excluded: the bundle transport (excluded
through requiring smart_options, which the bundle transport doesn't
support) and transport helpers that do not support takeover. If or when
we support independent negotiation for protocol v0, we will need to
modify these 2 code paths to support it. But for now, report failure if
independent negotiation is requested in these cases.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-05 10:41:29 +09:00
Jeff King
45a187cc34 lookup_unknown_object(): take a repository argument
All of the other lookup_foo() functions take a repository argument, but
lookup_unknown_object() was never converted, and it uses the_repository
internally. Let's fix that.

We could leave a wrapper that uses the_repository, but there aren't that
many calls, so we'll just convert them all. I looked briefly at each
site to see if we had a repository struct (besides the_repository) we
could pass, but none of them do (so this conversion to pass
the_repository is a pure noop in each case, though it does take us one
step closer to eventually getting rid of the_repository).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-13 13:18:46 -07:00
Junio C Hamano
8b4701ae4f Merge branch 'ak/corrected-commit-date'
The commit-graph learned to use corrected commit dates instead of
the generation number to help topological revision traversal.

* ak/corrected-commit-date:
  doc: add corrected commit date info
  commit-reach: use corrected commit dates in paint_down_to_common()
  commit-graph: use generation v2 only if entire chain does
  commit-graph: implement generation data chunk
  commit-graph: implement corrected commit date
  commit-graph: return 64-bit generation number
  commit-graph: add a slab to store topological levels
  t6600-test-reach: generalize *_three_modes
  commit-graph: consolidate fill_commit_graph_info
  revision: parse parent in indegree_walk_step()
  commit-graph: fix regression when computing Bloom filters
2021-02-17 17:21:40 -08:00
Junio C Hamano
60f8121940 Merge branch 'jv/upload-pack-filter-spec-quotefix'
Fix in passing custom args from "git clone" to "upload-pack" on the
other side.

* jv/upload-pack-filter-spec-quotefix:
  t5544: clarify 'hook works with partial clone' test
  upload-pack.c: fix filter spec quoting bug
2021-02-12 14:21:04 -08:00
Jacob Vosmaer
ad5df6b782 upload-pack.c: fix filter spec quoting bug
Fix a bug in upload-pack.c that occurs when you combine partial
clone and uploadpack.packObjectsHook. You can reproduce it as
follows:

    git clone -u 'git -c uploadpack.allowfilter '\
	'-c uploadpack.packobjectshook=env '\
	'upload-pack' --filter=blob:none --no-local \
	src.git dst.git

Be careful with the line endings because this has a long quoted
string as the -u argument.

The error I get when I run this is:

	Cloning into '/tmp/broken'...
	remote: fatal: invalid filter-spec ''blob:none''
	error: git upload-pack: git-pack-objects died with error.
	fatal: git upload-pack: aborting due to possible repository corruption on the remote side.
	remote: aborting due to possible repository corruption on the remote side.
	fatal: early EOF
	fatal: index-pack failed

The problem is caused by unneeded quoting.

This bug was already present in 10ac85c785 (upload-pack: add object
filtering for partial clone, 2017-12-08) when the server side filter
support was introduced.  In fact, in 10ac85c785 this was broken
regardless of uploadpack.packObjectsHook. Then in 0b6069fe0a
(fetch-pack: test support excluding large blobs, 2017-12-08) the
quoting was removed but only behind a conditional that depends on
whether uploadpack.packObjectsHook is set.

Because uploadpack.packObjectsHook is apparently rarely used, nobody
noticed the problematic quoting could still happen.

Remove the conditional quoting and add a test for partial clone in
t5544-pack-objects-hook.

Signed-off-by: Jacob Vosmaer <jacob@gitlab.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-28 09:40:24 -08:00
Jeff King
36a317929b refs: switch peel_ref() to peel_iterated_oid()
The peel_ref() interface is confusing and error-prone:

  - it's typically used by ref iteration callbacks that have both a
    refname and oid. But since they pass only the refname, we may load
    the ref value from the filesystem again. This is inefficient, but
    also means we are open to a race if somebody simultaneously updates
    the ref. E.g., this:

      int some_ref_cb(const char *refname, const struct object_id *oid, ...)
      {
              if (!peel_ref(refname, &peeled))
                      printf("%s peels to %s",
                             oid_to_hex(oid), oid_to_hex(&peeled);
      }

    could print nonsense. It is correct to say "refname peels to..."
    (you may see the "before" value or the "after" value, either of
    which is consistent), but mentioning both oids may be mixing
    before/after values.

    Worse, whether this is possible depends on whether the optimization
    to read from the current iterator value kicks in. So it is actually
    not possible with:

      for_each_ref(some_ref_cb);

    but it _is_ possible with:

      head_ref(some_ref_cb);

    which does not use the iterator mechanism (though in practice, HEAD
    should never peel to anything, so this may not be triggerable).

  - it must take a fully-qualified refname for the read_ref_full() code
    path to work. Yet we routinely pass it partial refnames from
    callbacks to for_each_tag_ref(), etc. This happens to work when
    iterating because there we do not call read_ref_full() at all, and
    only use the passed refname to check if it is the same as the
    iterator. But the requirements for the function parameters are quite
    unclear.

Instead of taking a refname, let's instead take an oid. That fixes both
problems. It's a little funny for a "ref" function not to involve refs
at all. The key thing is that it's optimizing under the hood based on
having access to the ref iterator. So let's change the name to make it
clear why you'd want this function versus just peel_object().

There are two other directions I considered but rejected:

  - we could pass the peel information into the each_ref_fn callback.
    However, we don't know if the caller actually wants it or not. For
    packed-refs, providing it is essentially free. But for loose refs,
    we actually have to peel the object, which would be wasteful in most
    cases. We could likewise pass in a flag to the callback indicating
    whether the peeled information is known, but that complicates those
    callbacks, as they then have to decide whether to manually peel
    themselves. Plus it requires changing the interface of every
    callback, whether they care about peeling or not, and there are many
    of them.

  - we could make a function to return the peeled value of the current
    iterated ref (computing it if necessary), and BUG() otherwise. I.e.:

      int peel_current_iterated_ref(struct object_id *out);

    Each of the current callers is an each_ref_fn callback, so they'd
    mostly be happy. But:

      - we use those callbacks with functions like head_ref(), which do
        not use the iteration code. So we'd need to handle the fallback
        case there, anyway.

      - it's possible that a caller would want to call into generic code
        that sometimes is used during iteration and sometimes not. This
        encapsulates the logic to do the fast thing when possible, and
        fallback when necessary.

The implementation is mostly obvious, but I want to call out a few
things in the patch:

  - the test-tool coverage for peel_ref() is now meaningless, as it all
    collapses to a single peel_object() call (arguably they were pretty
    uninteresting before; the tricky part of that function is the
    fast-path we see during iteration, but these calls didn't trigger
    that). I've just dropped it entirely, though note that some other
    tests relied on the tags we created; I've moved that creation to the
    tests where it matters.

  - we no longer need to take a ref_store parameter, since we'd never
    look up a ref now. We do still rely on a global "current iterator"
    variable which _could_ be kept per-ref-store. But in practice this
    is only useful if there are multiple recursive iterations, at which
    point the more appropriate solution is probably a stack of
    iterators. No caller used the actual ref-store parameter anyway
    (they all call the wrapper that passes the_repository).

  - the original only kicked in the optimization when the "refname"
    pointer matched (i.e., not string comparison). We do likewise with
    the "oid" parameter here, but fall back to doing an actual oideq()
    call. This in theory lets us kick in the optimization more often,
    though in practice no current caller cares. It should never be
    wrong, though (peeling is a property of an object, so two refs
    pointing to the same object would peel identically).

  - the original took care not to touch the peeled out-parameter unless
    we found something to put in it. But no caller cares about this, and
    anyway, it is enforced by peel_object() itself (and even in the
    optimized iterator case, that's where we eventually end up). We can
    shorten the code and avoid an extra copy by just passing the
    out-parameter through the stack.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-21 15:51:31 -08:00
Abhishek Kumar
d7f92784c6 commit-graph: return 64-bit generation number
In a preparatory step for introducing corrected commit dates, let's
return timestamp_t values from commit_graph_generation(), use
timestamp_t for local variables and define GENERATION_NUMBER_INFINITY
as (2 ^ 63 - 1) instead.

We rename GENERATION_NUMBER_MAX to GENERATION_NUMBER_V1_MAX to
represent the largest topological level we can store in the commit data
chunk.

With corrected commit dates implemented, we will have two such *_MAX
variables to denote the largest offset and largest topological level
that can be stored.

Signed-off-by: Abhishek Kumar <abhishekkumar8222@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-18 16:21:18 -08:00
Junio C Hamano
21127fa982 Merge branch 'tb/partial-clone-filters-fix'
Fix potential server side resource deallocation issues when
responding to a partial clone request.

* tb/partial-clone-filters-fix:
  upload-pack.c: don't free allowed_filters util pointers
  builtin/clone.c: don't ignore transport_fetch_refs() errors
2020-12-17 15:06:40 -08:00
Junio C Hamano
3c9f0df16a Merge branch 'jk/multi-line-indent-style-fix'
Style fix.

* jk/multi-line-indent-style-fix:
  style: indent multiline "if" conditions to align
2020-12-14 10:21:38 -08:00
Junio C Hamano
a5e74b4baa Merge branch 'jk/check-config-parsing-error-in-upload-pack'
Tighten error checking in the codepath that responds to "git fetch".

* jk/check-config-parsing-error-in-upload-pack:
  upload-pack: propagate return value from object filter config callback
2020-12-14 10:21:37 -08:00
Junio C Hamano
01b8886a62 Merge branch 'js/trace2-session-id'
The transport layer was taught to optionally exchange the session
ID assigned by the trace2 subsystem during fetch/push transactions.

* js/trace2-session-id:
  receive-pack: log received client session ID
  send-pack: advertise session ID in capabilities
  upload-pack, serve: log received client session ID
  fetch-pack: advertise session ID in capabilities
  transport: log received server session ID
  serve: advertise session ID in v2 capabilities
  receive-pack: advertise session ID in v0 capabilities
  upload-pack: advertise session ID in v0 capabilities
  trace2: add a public function for getting the SID
  docs: new transfer.advertiseSID option
  docs: new capability to advertise session IDs
2020-12-08 15:11:20 -08:00
Taylor Blau
8d133f500a upload-pack.c: don't free allowed_filters util pointers
To keep track of which object filters are allowed or not, 'git
upload-pack' stores the name of each filter in a string_list, and sets
it ->util pointer to be either 0 or 1, indicating whether it is banned
or allowed.

Later on, we attempt to clear that list, but we incorrectly ask for the
util pointers to be free()'d, too. This behavior (introduced back in
6dd3456a8c (upload-pack.c: allow banning certain object filter(s),
2020-08-03)) leads to an invalid free, and causes us to crash.

In order to trigger this, one needs to fetch from a server that (a) has
at least one object filter allowed, and (b) issue a fetch that contains
a subset of the allowed filters (i.e., we cannot ask for a banned
filter, since this causes us to die() before we hit the bogus
string_list_clear()).

In that case, whatever banned filters exist will cause a noop free()
(since those ->util pointers are set to 0), but the first allowed filter
we try to free will crash us.

We never noticed this in the tests because we didn't have an example of
setting 'uploadPackFilter' configuration variables and then following up
with a valid fetch. The first new 'git clone' prevents further
regression here. For good measure on top, add a test which checks the
same behavior at a tree depth greater than 0.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-03 12:42:33 -08:00
Jeff King
08e9df2395 style: indent multiline "if" conditions to align
Commit 6dc905d974 (config: split repo scope to local and worktree,
2020-02-10) made some "if" statements multiline, but didn't indent the
second lines in our usual way.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-03 10:32:32 -08:00
Jeff King
d43a21bdbb upload-pack: propagate return value from object filter config callback
If we encounter an error in parse_filter_object_config(), we'll complain
to stderr but won't actually propagate the return value up the stack.
This is unlike most of our config callbacks, which return the error to
git_config() so it can die (this includes the call just below us to
parse_hide_refs_config(), which can also produce errors).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-03 10:25:13 -08:00
Junio C Hamano
f3a112a75e Merge branch 'jk/stop-pack-objects-when-fetch-is-killed'
"git fetch" that is killed may leave a pack-objects process behind,
still computing to find a good compression, wasting cycles.  This
has been corrected.

* jk/stop-pack-objects-when-fetch-is-killed:
  upload-pack: kill pack-objects helper on signal or exit
2020-12-03 00:18:07 -08:00
Jeff King
309a4028e7 upload-pack: kill pack-objects helper on signal or exit
We spawn an external pack-objects process to actually send objects to
the remote side. If we are killed by a signal during this process, then
pack-objects may continue to run. As soon as it starts producing output
for the pack, it will see a failure writing to upload-pack and exit
itself. But before then, it may do significant work traversing the
object graph, compressing deltas, etc, which will all be pointless. So
let's make sure to kill as soon as we know that the caller will not read
the result.

There's no test here, since it's inherently racy, but here's an easy
reproduction is on a large-ish repo like linux.git:

  - make sure you don't have pack bitmaps (since they make the enumerating
    phase go quickly). For linux.git it takes ~30s or so to walk the
    whole graph on my machine.

  - run "git clone --no-local -q . dst"; the "-q" is important because
    if pack-objects is writing progress to upload-pack (to get
    multiplexed over the sideband to the client), then it will notice
    pretty quickly the failure to write to stderr

  - kill the client-side clone process in another terminal (don't use
    ^C, as that will send SIGINT to all of the processes)

  - run "ps au | grep git" or similar to observe upload-pack dying
    within 5 seconds (it will send a keepalive that will notice the
    client has gone away)

  - but you'll still see pack-objects consuming 100% CPU (and 1GB+ of
    RAM) during the traversal and delta compression phases. It will exit
    as soon as it starts to write the pack (when it will notice that
    upload-pack went away).

With this patch, pack-objects exits as soon as upload-pack does.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-01 12:05:58 -08:00
Josh Steadmon
829594677c upload-pack, serve: log received client session ID
When upload-pack (protocol v0/v1) or a protocol v2 server receives a
session-id capability from a client, log the received session ID via a
trace2 data event.

Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-11 18:26:53 -08:00
Josh Steadmon
791e1adf22 upload-pack: advertise session ID in v0 capabilities
When transfer.advertiseSID is true, advertise upload-pack's session ID
via the new session-id capability.

Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-11 18:26:52 -08:00
Daniel Duvall
fb3d1a083f upload-pack: allow stateless client EOF just prior to haves
During stateless packfile negotiation where a depth is given, stateless
RPC clients (e.g. git-remote-curl) will send multiple upload-pack
requests with the first containing only the
wants/shallows/deepens/filters and the subsequent containing haves/done.

When upload-pack handles such requests, entering get_common_commits
without checking whether the client has hung up can result in unexpected
EOF during the negotiation loop and a die() with message "fatal: the
remote end hung up unexpectedly".

Real world effects include:

 - A client speaking to git-http-backend via a server that doesn't check
   the exit codes of CGIs (e.g. mod_cgi) doesn't know and doesn't care
   about the fatal. It continues to process the response body as normal.

 - A client speaking to a server that does check the exit code and
   returns an errant HTTP status as a result will fail with the message
   "error: RPC failed; HTTP 500 curl 22 The requested URL returned error:
   500."

 - Admins running servers that surface the failure must workaround it by
   patching code that handles execution of git-http-backend to ignore exit
   codes or take other heuristic approaches.

 - Admins may have to deal with "hung up unexpectedly" log spam related
   to the failures even in cases where the exit code isn't surfaced as an
   HTTP server-side error status.

To avoid these EOF related fatals, have upload-pack gently peek for an
EOF between the sending of shallow/unshallow lines (followed by flush)
and the reading of client haves. If the client has hung up at this
point, exit normally.

Signed-off-by: Daniel Duvall <dan@mutual.io>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-30 21:18:10 -07:00
Junio C Hamano
d8488b9e86 Merge branch 'rs/more-buffered-io'
Use more buffered I/O where we used to call many small write(2)s.

* rs/more-buffered-io:
  upload-pack: use buffered I/O to talk to rev-list
  midx: use buffered I/O to talk to pack-objects
  connected: use buffered I/O to talk to rev-list
2020-08-24 14:54:31 -07:00
Junio C Hamano
f577d305c7 Merge branch 'rs/upload-pack-sigchain-fix'
Code clean-up.

* rs/upload-pack-sigchain-fix:
  upload-pack: remove superfluous sigchain_pop() call
2020-08-19 16:14:45 -07:00
René Scharfe
a698d67b08 upload-pack: use buffered I/O to talk to rev-list
Like f0bca72dc7 (send-pack: use buffered I/O to talk to pack-objects,
2016-06-08), significantly reduce the number of system calls and
simplify the code for sending object IDs to rev-list by using stdio's
buffering.

Take care to handle errors immediately to get the correct error code,
and to flush the buffer explicitly before closing the stream in order to
catch any write errors for these last bytes.

Helped-by: Chris Torek <chris.torek@gmail.com>
Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-17 10:29:39 -07:00
Junio C Hamano
73a9255166 Merge branch 'tb/upload-pack-filters'
The component to respond to "git fetch" request is made more
configurable to selectively allow or reject object filtering
specification used for partial cloning.

* tb/upload-pack-filters:
  t5616: use test_i18ngrep for upload-pack errors
  upload-pack.c: introduce 'uploadpackfilter.tree.maxDepth'
  upload-pack.c: allow banning certain object filter(s)
  list_objects_filter_options: introduce 'list_object_filter_config_name'
2020-08-11 18:04:13 -07:00
René Scharfe
e767963ab6 upload-pack: remove superfluous sigchain_pop() call
2997178ee6 (upload-pack: split check_unreachable() in two, prep for
get_reachable_list(), 2016-06-12) moved most code of has_unreachable()
into the new function do_reachable_revlist().  The latter takes care to
ignore SIGPIPE during its operations, and restores the original signal
handler before returning.

However, a sigchain_pop(SIGPIPE) call remained in the error handling
code of has_unreachable(), which does nothing because the stack is
empty after do_reachable_revlist() cleaned up after itself.  Remove it.

Signed-off-by: René Scharfe <l.s.r@web.de>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-11 14:01:18 -07:00
Junio C Hamano
46b225f153 Merge branch 'jk/strvec'
The argv_array API is useful for not just managing argv but any
"vector" (NULL-terminated array) of strings, and has seen adoption
to a certain degree.  It has been renamed to "strvec" to reduce the
barrier to adoption.

* jk/strvec:
  strvec: rename struct fields
  strvec: drop argv_array compatibility layer
  strvec: update documention to avoid argv_array
  strvec: fix indentation in renamed calls
  strvec: convert remaining callers away from argv_array name
  strvec: convert more callers away from argv_array name
  strvec: convert builtin/ callers away from argv_array name
  quote: rename sq_dequote_to_argv_array to mention strvec
  strvec: rename files from argv-array to strvec
  argv-array: rename to strvec
  argv-array: use size_t for count and alloc
2020-08-10 10:23:57 -07:00
Taylor Blau
5b01a4e8ff upload-pack.c: introduce 'uploadpackfilter.tree.maxDepth'
In b79cf959b2 (upload-pack.c: allow banning certain object filter(s),
2020-02-26), we introduced functionality to disallow certain object
filters from being chosen from within 'git upload-pack'. Traditionally,
administrators use this functionality to disallow filters that are known
to perform slowly, for e.g., those that do not have bitmap-level
filtering.

In the past, the '--filter=tree:<n>' was one such filter that does not
have bitmap-level filtering support, and so was likely to be banned by
administrators.

However, in the previous couple of commits, we introduced bitmap-level
filtering for the case when 'n' is equal to '0', i.e., as if we had a
'--filter=tree:none' choice.

While it would be sufficient to simply write

  $ git config uploadpackfilter.tree.allow true

(since it would allow all values of 'n'), we would like to be able to
allow this filter for certain values of 'n', i.e., those no greater than
some pre-specified maximum.

In order to do this, introduce a new configuration key, as follows:

  $ git config uploadpackfilter.tree.maxDepth <m>

where '<m>' specifies the maximum allowed value of 'n' in the filter
'tree:n'. Administrators who wish to allow for only the value '0' can
write:

  $ git config uploadpackfilter.tree.allow true
  $ git config uploadpackfilter.tree.maxDepth 0

which allows '--filter=tree:0', but no other values.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-03 18:03:46 -07:00
Taylor Blau
6dd3456a8c upload-pack.c: allow banning certain object filter(s)
Git clients may ask the server for a partial set of objects, where the
set of objects being requested is refined by one or more object filters.
Server administrators can configure 'git upload-pack' to allow or ban
these filters by setting the 'uploadpack.allowFilter' variable to
'true' or 'false', respectively.

However, administrators using bitmaps may wish to allow certain kinds of
object filters, but ban others. Specifically, they may wish to allow
object filters that can be optimized by the use of bitmaps, while
rejecting other object filters which aren't and represent a perceived
performance degradation (as well as an increased load factor on the
server).

Allow configuring 'git upload-pack' to support object filters on a
case-by-case basis by introducing two new configuration variables:

  - 'uploadpackfilter.allow'
  - 'uploadpackfilter.<kind>.allow'

where '<kind>' may be one of 'blobNone', 'blobLimit', 'tree', and so on.

Setting the second configuration variable for any valid value of
'<kind>' explicitly allows or disallows restricting that kind of object
filter.

If a client requests the object filter <kind> and the respective
configuration value is not set, 'git upload-pack' will default to the
value of 'uploadpackfilter.allow', which itself defaults to 'true' to
maintain backwards compatibility. Note that this differs from
'uploadpack.allowfilter', which controls whether or not the 'filter'
capability is advertised.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-03 18:03:41 -07:00
Jeff King
d70a9eb611 strvec: rename struct fields
The "argc" and "argv" names made sense when the struct was argv_array,
but now they're just confusing. Let's rename them to "nr" (which we use
for counts elsewhere) and "v" (which is rather terse, but reads well
when combined with typical variable names like "args.v").

Note that we have to update all of the callers immediately. Playing
tricks with the preprocessor is hard here, because we wouldn't want to
rewrite unrelated tokens.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30 19:18:06 -07:00
Jeff King
f6d8942b1f strvec: fix indentation in renamed calls
Code which split an argv_array call across multiple lines, like:

  argv_array_pushl(&args, "one argument",
                   "another argument", "and more",
		   NULL);

was recently mechanically renamed to use strvec, which results in
mis-matched indentation like:

  strvec_pushl(&args, "one argument",
                   "another argument", "and more",
		   NULL);

Let's fix these up to align the arguments with the opening paren. I did
this manually by sifting through the results of:

  git jump grep 'strvec_.*,$'

and liberally applying my editor's auto-format. Most of the changes are
of the form shown above, though I also normalized a few that had
originally used a single-tab indentation (rather than our usual style of
aligning with the open paren). I also rewrapped a couple of obvious
cases (e.g., where previously too-long lines became short enough to fit
on one), but I wasn't aggressive about it. In cases broken to three or
more lines, the grouping of arguments is sometimes meaningful, and it
wasn't worth my time or reviewer time to ponder each case individually.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:18 -07:00
Jeff King
c972bf4cf5 strvec: convert remaining callers away from argv_array name
We eventually want to drop the argv_array name and just use strvec
consistently. There's no particular reason we have to do it all at once,
or care about interactions between converted and unconverted bits.
Because of our preprocessor compat layer, the names are interchangeable
to the compiler (so even a definition and declaration using different
names is OK).

This patch converts all of the remaining files, as the resulting diff is
reasonably sized.

The conversion was done purely mechanically with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe '
    s/ARGV_ARRAY/STRVEC/g;
    s/argv_array/strvec/g;
  '

We'll deal with any indentation/style fallouts separately.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:18 -07:00
Jeff King
dbbcd44fb4 strvec: rename files from argv-array to strvec
This requires updating #include lines across the code-base, but that's
all fairly mechanical, and was done with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe 's/argv-array.h/strvec.h/'

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:17 -07:00
Jonathan Tan
77aa0941ce upload-pack: do not lazy-fetch "have" objects
When upload-pack receives a request containing "have" hashes, it (among
other things) checks if the served repository has the corresponding
objects. However, it does not do so with the
OBJECT_INFO_SKIP_FETCH_OBJECT flag, so if serving a partial clone, a
lazy fetch will be triggered first.

This was discovered at $DAYJOB when a user fetched from a partial clone
(into another partial clone - although this would also happen if the
repo to be fetched into is not a partial clone).

Therefore, whenever "have" hashes are checked for existence, pass the
OBJECT_INFO_SKIP_FETCH_OBJECT flag. Also add the OBJECT_INFO_QUICK flag
to improve performance, as it is typical that such objects do not exist
in the serving repo, and the consequences of a false negative are minor
(usually, a slightly larger pack sent).

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-16 14:07:19 -07:00
Junio C Hamano
12210859da Merge branch 'bc/sha-256-part-2'
SHA-256 migration work continues.

* bc/sha-256-part-2: (44 commits)
  remote-testgit: adapt for object-format
  bundle: detect hash algorithm when reading refs
  t5300: pass --object-format to git index-pack
  t5704: send object-format capability with SHA-256
  t5703: use object-format serve option
  t5702: offer an object-format capability in the test
  t/helper: initialize the repository for test-sha1-array
  remote-curl: avoid truncating refs with ls-remote
  t1050: pass algorithm to index-pack when outside repo
  builtin/index-pack: add option to specify hash algorithm
  remote-curl: detect algorithm for dumb HTTP by size
  builtin/ls-remote: initialize repository based on fetch
  t5500: make hash independent
  serve: advertise object-format capability for protocol v2
  connect: parse v2 refs with correct hash algorithm
  connect: pass full packet reader when parsing v2 refs
  Documentation/technical: document object-format for protocol v2
  t1302: expect repo format version 1 for SHA-256
  builtin/show-index: provide options to determine hash algo
  t5302: modernize test formatting
  ...
2020-07-06 22:09:13 -07:00
Junio C Hamano
34e849b05a Merge branch 'jt/cdn-offload'
The "fetch/clone" protocol has been updated to allow the server to
instruct the clients to grab pre-packaged packfile(s) in addition
to the packed object data coming over the wire.

* jt/cdn-offload:
  upload-pack: fix a sparse '0 as NULL pointer' warning
  upload-pack: send part of packfile response as uri
  fetch-pack: support more than one pack lockfile
  upload-pack: refactor reading of pack-objects out
  Documentation: add Packfile URIs design doc
  Documentation: order protocol v2 sections
  http-fetch: support fetching packfiles by URL
  http-fetch: refactor into function
  http: refactor finish_http_pack_request()
  http: use --stdin when indexing dumb HTTP pack
2020-06-25 12:27:47 -07:00
Ramsay Jones
cae2ee1055 upload-pack: fix a sparse '0 as NULL pointer' warning
Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-17 13:22:40 -07:00
Christian Couder
ea2c6e6083 upload-pack: refactor common code into do_got_oid()
As 'upload-pack.c' is now using 'struct upload_pack_data'
thoroughly, let's refactor some common code into a new
do_got_oid() function.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-11 13:35:35 -07:00
Christian Couder
f01c7916b8 upload-pack: move oldest_have to upload_pack_data
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the 'oldest_have' static variable
into this struct.

It is used by both protocol v0 and protocol v2 code.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-11 13:35:35 -07:00
Christian Couder
460ed0d4b4 upload-pack: pass upload_pack_data to got_oid()
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's pass that struct to got_oid(), so that
this function can use all the fields of the struct.

This will be used in followup commits to move a static variable
into 'upload_pack_data'.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-11 13:35:35 -07:00
Christian Couder
0866734820 upload-pack: pass upload_pack_data to ok_to_give_up()
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's pass that struct to ok_to_give_up(), so
that this function can use all the fields of the struct.

This will be used in followup commits to move a static variable
into 'upload_pack_data'.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-11 13:35:35 -07:00
Christian Couder
6fbbc4374f upload-pack: pass upload_pack_data to send_acks()
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's pass that struct to send_acks(), so
that this function can use all the fields of the struct.

This will be used in followup commits to move a static variable
into 'upload_pack_data'.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-11 13:35:35 -07:00
Christian Couder
8dcf22785f upload-pack: pass upload_pack_data to process_haves()
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's pass that struct to process_haves(), so
that this function can use all the fields of the struct.

This will be used in followup commits to move a static variable
into 'upload_pack_data'.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-11 13:35:35 -07:00