Use struct object_id in three fields in struct ref and convert all the
necessary places that use it.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
In addition to matching stripped refs, one can now add hideRefs
patterns that the full (unstripped) ref is matched against. To
distinguish between stripped and full matches, those new patterns
must be prefixed with a circumflex (^).
This commit also removes support for the undocumented and unintended
hideRefs settings ".have" (suppressing all "have" lines) and
"capabilities^{}" (suppressing the capabilities line).
Signed-off-by: Lukas Fleischer <lfleischer@lfos.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To generate "--keep=receive-pack $pid on $host", we write
progressively into a single buffer, which requires keeping
track of how much we've written so far. But since the result
is destined to go into our argv array, we can simply use
argv_array_pushf.
Unfortunately we still have to have a fixed-size buffer for
the gethostname() call, but at least it now doesn't involve
any extra size computation. And as a bonus, we drop an
sprintf and a strcpy call.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before sha1_to_hex_r() existed, a simple way to get hex
sha1 into a buffer was with:
strcpy(buf, sha1_to_hex(sha1));
This isn't wrong (assuming the buf is 41 characters), but it
makes auditing the code base for bad strcpy() calls harder,
as these become false positives.
Let's convert them to sha1_to_hex_r(), and likewise for
some calls to find_unique_abbrev(). While we're here, we'll
double-check that all of the buffers are correctly sized,
and use the more obvious GIT_SHA1_HEXSZ constant.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This strncpy is pointless; we pass the strlen() of the src
string, meaning that it works just like a memcpy. Worse,
though, is that the size has no relation to the destination
buffer, meaning it is a potential overflow. In practice,
it's not. We pass only short constant strings like
"warning: " and "error: ", which are much smaller than the
destination buffer.
We can make this much simpler by just using xsnprintf, which
will check for overflow and return the size for our next
vsnprintf, without us having to run a separate strlen().
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An attempt to delete a ref by pushing into a repositorywhose HEAD
symbolic reference points at an unborn branch that cannot be
created due to ref D/F conflict (e.g. refs/heads/a/b exists, HEAD
points at refs/heads/a) failed.
* jx/do-not-crash-receive-pack-wo-head:
receive-pack: crash when checking with non-exist HEAD
If HEAD of a repository points to a conflict reference, such as:
* There exist a reference named 'refs/heads/jx/feature1', but HEAD
points to 'refs/heads/jx', or
* There exist a reference named 'refs/heads/feature', but HEAD points
to 'refs/heads/feature/bad'.
When we push to delete a reference for this repo, such as:
git push /path/to/bad-head-repo.git :some/good/reference
The git-receive-pack process will crash.
This is because if HEAD points to a conflict reference, the function
`resolve_refdup("HEAD", ...)` does not return a valid reference name,
but a null buffer. Later matching the delete reference against the null
buffer will cause git-receive-pack crash.
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The optional new config option `receive.fsck.skipList` specifies the path
to a file listing the names, i.e. SHA-1s, one per line, of objects that
are to be ignored by `git receive-pack` when `receive.fsckObjects = true`.
This is extremely handy in case of legacy repositories where it would
cause more pain to change incorrect objects than to live with them
(e.g. a duplicate 'author' line in an early commit object).
The intended use case is for server administrators to inspect objects
that are reported by `git push` as being too problematic to enter the
repository, and to add the objects' SHA-1 to a (preferably sorted) file
when the objects are legitimate, i.e. when it is determined that those
problematic objects should be allowed to enter the server.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For example, missing emails in commit and tag objects can be demoted to
mere warnings with
git config receive.fsck.missingemail=warn
The value is actually a comma-separated list.
In case that the same key is listed in multiple receive.fsck.<msg-id>
lines in the config, the latter configuration wins (this can happen for
example when both $HOME/.gitconfig and .git/config contain message type
settings).
As git receive-pack does not actually perform the checks, it hands off
the setting to index-pack or unpack-objects in the form of an optional
argument to the --strict option.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change typedef each_ref_fn to take a "const struct object_id *oid"
parameter instead of "const unsigned char *sha1".
To aid this transition, implement an adapter that can be used to wrap
old-style functions matching the old typedef, which is now called
"each_ref_sha1_fn"), and make such functions callable via the new
interface. This requires the old function and its cb_data to be
wrapped in a "struct each_ref_fn_sha1_adapter", and that object to be
used as the cb_data for an adapter function, each_ref_fn_adapter().
This is an enormous diff, but most of it consists of simple,
mechanical changes to the sites that call any of the "for_each_ref"
family of functions. Subsequent to this change, the call sites can be
rewritten one by one to use the new interface.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A replacement for contrib/workdir/git-new-workdir that does not
rely on symbolic links and make sharing of objects and refs safer
by making the borrowee and borrowers aware of each other.
* nd/multiple-work-trees: (41 commits)
prune --worktrees: fix expire vs worktree existence condition
t1501: fix test with split index
t2026: fix broken &&-chain
t2026 needs procondition SANITY
git-checkout.txt: a note about multiple checkout support for submodules
checkout: add --ignore-other-wortrees
checkout: pass whole struct to parse_branchname_arg instead of individual flags
git-common-dir: make "modules/" per-working-directory directory
checkout: do not fail if target is an empty directory
t2025: add a test to make sure grafts is working from a linked checkout
checkout: don't require a work tree when checking out into a new one
git_path(): keep "info/sparse-checkout" per work-tree
count-objects: report unused files in $GIT_DIR/worktrees/...
gc: support prune --worktrees
gc: factor out gc.pruneexpire parsing code
gc: style change -- no SP before closing parenthesis
checkout: clean up half-prepared directories in --to mode
checkout: reject if the branch is already checked out elsewhere
prune: strategies for linked checkouts
checkout: support checking out into a new working directory
...
A push into an unborn branch, with "receive.denyCurrentBranch" set
to "updateInstead", did not check out the working tree as expected.
* jc/update-instead-into-void:
push-to-deploy: allow pushing into an unborn branch and updating it
Setting receive.denycurrentbranch to updateinstead and pushing into
the current branch, when the working tree and the index is truly
clean, is supposed to reset the working tree and the index to match
the tree of the pushed commit. This did not work when pushing into
an unborn branch.
The code that drives push-to-checkout hook needs no change, as the
interface is defined so that hook can decide what to do when the
push is coming to an unborn branch and take an appropriate action
since the beginning.
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead, verify the reference's old value if and only if old_sha1 is
non-NULL.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead, verify the reference's old value if and only if old_sha1 is
non-NULL.
ref_transaction_delete() will get the same treatment in a moment.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Extending the js/push-to-deploy topic, the behaviour of "git push"
when updating the working tree and the index with an update to the
branch that is checked out can be tweaked by push-to-checkout hook.
* jc/push-to-checkout:
receive-pack: support push-to-checkout hook
receive-pack: refactor updateInstead codepath
"git push" has been taught a "--atomic" option that makes push to
update more than one ref an "all-or-none" affair.
* sb/atomic-push:
Document receive.advertiseatomic
t5543-atomic-push.sh: add basic tests for atomic pushes
push.c: add an --atomic argument
send-pack.c: add --atomic command line argument
send-pack: rename ref_update_to_be_sent to check_to_send_update
receive-pack.c: negotiate atomic push support
receive-pack.c: add execute_commands_atomic function
receive-pack.c: move transaction handling in a central place
receive-pack.c: move iterating over all commands outside execute_commands
receive-pack.c: die instead of error in case of possible future bug
receive-pack.c: shorten the execute_commands loop over all commands
When receive.denyCurrentBranch is set to updateInstead, a push that
tries to update the branch that is currently checked out is accepted
only when the index and the working tree exactly matches the
currently checked out commit, in which case the index and the
working tree are updated to match the pushed commit. Otherwise the
push is refused.
This hook can be used to customize this "push-to-deploy" logic. The
hook receives the commit with which the tip of the current branch is
going to be updated, and can decide what kind of local changes are
acceptable and how to update the index and the working tree to match
the updated tip of the current branch.
For example, the hook can simply run `git read-tree -u -m HEAD "$1"`
in order to emulate 'git fetch' that is run in the reverse direction
with `git push`, as the two-tree form of `read-tree -u -m` is
essentially the same as `git checkout` that switches branches while
keeping the local changes in the working tree that do not interfere
with the difference between the branches.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This adds the atomic protocol option to allow
receive-pack to inform the client that it has
atomic push capability.
This commit makes the functionality introduced
in the previous commits go live for the serving
side. The changes in documentation reflect the
protocol capabilities of the server.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This introduces the new function execute_commands_atomic which will use
one atomic transaction for all updates. The default behavior is still
the old non atomic way, one ref at a time. This is to cause as little
disruption as possible to existing clients. It is unknown if there are
client scripts that depend on the old non-atomic behavior so we make it
opt-in for now.
A later patch will add the possibility to actually use the functionality
added by this patch. For now use_atomic is always 0.
Inspired-by: Ronnie Sahlberg <sahlberg@google.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This moves all code related to transactions into the
execute_commands_non_atomic function. This includes
beginning and committing the transaction as well as
dealing with the errors which may occur during the
begin and commit phase of a transaction.
No functional changes intended.
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit allows us in a later patch to easily distinguish between
the non atomic way to update the received refs and the atomic way which
is introduced in a later patch.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Discussion on the previous patch revealed we rather want to err on the
safe side. To do so we need to stop receive-pack in case of the possible
future bug when connectivity is not checked on a shallow push.
Also while touching that code we considered that removing the reported
refs may be harmful in some situations. Sound the message more like a
"This Cannot Happen, Please Investigate!" instead of giving advice to
remove refs.
Suggested-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make the main "execute_commands" loop in receive-pack easier to read
by splitting out some steps into helper functions. The new helper
'should_process_cmd' checks if a ref update is unnecessary, whether
due to an error having occurred or for another reason. The helper
'warn_if_skipped_connectivity_check' warns if we have forgotten to
run a connectivity check on a ref which is shallow for the client
which would be a bug.
This will help us to duplicate less code in a later patch when we make
a second copy of the "execute_commands" loop.
No functional change intended.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git push" into a repository with a working tree normally refuses
to modify the branch that is checked out. The command learned to
optionally do an equivalent of "git reset --hard" only when there
is no change to the working tree and the index instead, which would
be useful to "deploy" by pushing into a repository.
* js/push-to-deploy:
t5516: more tests for receive.denyCurrentBranch=updateInstead
receive-pack: add another option for receive.denyCurrentBranch
"git remote update --prune" to drop many refs has been optimized.
* mh/simplify-repack-without-refs:
sort_string_list(): rename to string_list_sort()
prune_remote(): iterate using for_each_string_list_item()
prune_remote(): rename local variable
repack_without_refs(): make the refnames argument a string_list
prune_remote(): sort delete_refs_list references en masse
prune_remote(): initialize both delete_refs lists in a single loop
prune_remote(): exit early if there are no stale references
Keep the "there is nothing to update in a bare repository", "when
the check and update process runs, here are the GIT_DIR and
GIT_WORK_TREE" logic, which will be common regardless of how the
decision to update and the actual update are done, in the original
update_worktree() function, and split out the "working tree and
the index must match the original HEAD exactly" and "use two-way
read-tree to update the working tree" into a new push_to_deploy()
helper function. This will allow customizing the logic more cleanly
and easily.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before the previous commit, get_pathname returns an array of PATH_MAX
length. Even if git_path() and similar functions does not use the
whole array, git_path() caller can, in theory.
After the commit, get_pathname() may return a buffer that has just
enough room for the returned string and git_path() caller should never
write beyond that.
Make git_path(), mkpath() and git_path_submodule() return a const
buffer to make sure callers do not write in it at all.
This could have been part of the previous commit, but the "const"
conversion is too much distraction from the core changes in path.c.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When synchronizing between working directories, it can be handy to update
the current branch via 'push' rather than 'pull', e.g. when pushing a fix
from inside a VM, or when pushing a fix made on a user's machine (where
the developer is not at liberty to install an ssh daemon let alone know
the user's password).
The common workaround – pushing into a temporary branch and then merging
on the other machine – is no longer necessary with this patch.
The new option is:
'updateInstead':
Update the working tree accordingly, but refuse to do so if there
are any uncommitted changes.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The new name is more consistent with the names of other
string_list-related functions.
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Using abs() on long values can cause truncation, so use labs() instead.
Reported by Clang 3.5 (-Wabsolute-value, enabled by -Wall).
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If the asynchronous start of copy_to_sideband() fails, then any
env_array entries added to struct child_process proc by
prepare_push_cert_sha1() are leaked. Call the latter function only
after start_async() succeeded so that the allocated entries are
cleaned up automatically by start_command() or finish_command().
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add managed "env" array to child_process to clarify the lifetime
rules.
* rs/run-command-env-array:
use env_array member of struct child_process
run-command: add env_array, an optional argv_array for env
The API to update refs have been restructured to allow introducing
a true transactional updates later. We would even allow storing
refs in backends other than the traditional filesystem-based one.
* rs/ref-transaction: (25 commits)
ref_transaction_commit: bail out on failure to remove a ref
lockfile: remove unable_to_lock_error
refs.c: do not permit err == NULL
remote rm/prune: print a message when writing packed-refs fails
for-each-ref: skip and warn about broken ref names
refs.c: allow listing and deleting badly named refs
test: put tests for handling of bad ref names in one place
packed-ref cache: forbid dot-components in refnames
branch -d: simplify by using RESOLVE_REF_READING
branch -d: avoid repeated symref resolution
reflog test: test interaction with detached HEAD
refs.c: change resolve_ref_unsafe reading argument to be a flags field
refs.c: make write_ref_sha1 static
fetch.c: change s_update_ref to use a ref transaction
refs.c: ref_transaction_commit: distinguish name conflicts from other errors
refs.c: pass a list of names to skip to is_refname_available
refs.c: call lock_ref_sha1_basic directly from commit
refs.c: refuse to lock badly named refs in lock_ref_sha1_basic
rename_ref: don't ask read_ref_full where the ref came from
refs.c: pass the ref log message to _create/delete/update instead of _commit
...
Convert users of struct child_process to using the managed env_array for
specifying environment variables instead of supplying an array on the
stack or bringing their own argv_array. This shortens and simplifies
the code and ensures automatically that the allocated memory is freed
after use.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
resolve_ref_unsafe takes a boolean argument for reading (a nonexistent ref
resolves successfully for writing but not for reading). Change this to be
a flags field instead, and pass the new constant RESOLVE_REF_READING when
we want this behaviour.
While at it, swap two of the arguments in the function to put output
arguments at the end. As a nice side effect, this ensures that we can
catch callers that were unaware of the new API so they can be audited.
Give the wrapper functions resolve_refdup and read_ref_full the same
treatment for consistency.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the ref transaction API so that we pass the reflog message to the
create/delete/update functions instead of to ref_transaction_commit.
This allows different reflog messages for each ref update in a multi-ref
transaction.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The lockfile API and its users have been cleaned up.
* mh/lockfile: (38 commits)
lockfile.h: extract new header file for the functions in lockfile.c
hold_locked_index(): move from lockfile.c to read-cache.c
hold_lock_file_for_append(): restore errno before returning
get_locked_file_path(): new function
lockfile.c: rename static functions
lockfile: rename LOCK_NODEREF to LOCK_NO_DEREF
commit_lock_file_to(): refactor a helper out of commit_lock_file()
trim_last_path_component(): replace last_path_elm()
resolve_symlink(): take a strbuf parameter
resolve_symlink(): use a strbuf for internal scratch space
lockfile: change lock_file::filename into a strbuf
commit_lock_file(): use a strbuf to manage temporary space
try_merge_strategy(): use a statically-allocated lock_file object
try_merge_strategy(): remove redundant lock_file allocation
struct lock_file: declare some fields volatile
lockfile: avoid transitory invalid states
git_config_set_multivar_in_file(): avoid call to rollback_lock_file()
dump_marks(): remove a redundant call to rollback_lock_file()
api-lockfile: document edge cases
commit_lock_file(): rollback lock file on failure to rename
...
The argv_array used in unpack() is never freed. Instead of adding
explicit calls to argv_array_clear() use the args member of struct
child_process and let run_command() and friends clean up for us.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow "git push" request to be signed, so that it can be verified and
audited, using the GPG signature of the person who pushed, that the
tips of branches at a public repository really point the commits
the pusher wanted to, without having to "trust" the server.
* jc/push-cert: (24 commits)
receive-pack::hmac_sha1(): copy the entire SHA-1 hash out
signed push: allow stale nonce in stateless mode
signed push: teach smart-HTTP to pass "git push --signed" around
signed push: fortify against replay attacks
signed push: add "pushee" header to push certificate
signed push: remove duplicated protocol info
send-pack: send feature request on push-cert packet
receive-pack: GPG-validate push certificates
push: the beginning of "git push --signed"
pack-protocol doc: typofix for PKT-LINE
gpg-interface: move parse_signature() to where it should be
gpg-interface: move parse_gpg_output() to where it should be
send-pack: clarify that cmds_sent is a boolean
send-pack: refactor inspecting and resetting status and sending commands
send-pack: rename "new_refs" to "need_pack_data"
receive-pack: factor out capability string generation
send-pack: factor out capability string generation
send-pack: always send capabilities
send-pack: refactor decision to send update per ref
send-pack: move REF_STATUS_REJECT_NODELETE logic a bit higher
...
Move the interface declaration for the functions in lockfile.c from
cache.h to a new file, lockfile.h. Add #includes where necessary (and
remove some redundant includes of cache.h by files that already
include builtin.h).
Move the documentation of the lock_file state diagram from lockfile.c
to the new header file.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
pre- and post-receive hooks are no longer required to read all
their inputs.
* jc/ignore-sigpipe-while-running-hooks:
receive-pack: allow hooks to ignore its standard input stream
clang gives the following warning:
builtin/receive-pack.c:327:35: error: sizeof on array function
parameter will return size of 'unsigned char *' instead of 'unsigned
char [20]' [-Werror,-Wsizeof-array-argument]
git_SHA1_Update(&ctx, out, sizeof(out));
^
builtin/receive-pack.c:292:37: note: declared here
static void hmac_sha1(unsigned char out[20],
^
Signed-off-by: Brian Gernhardt <brian@gernhardtsoftware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When operating with the stateless RPC mode, we will receive a nonce
issued by another instance of us that advertised our capability and
refs some time ago. Update the logic to check received nonce to
detect this case, compute how much time has passed since the nonce
was issued and report the status with a new environment variable
GIT_PUSH_CERT_NONCE_SLOP to the hooks.
GIT_PUSH_CERT_NONCE_STATUS will report "SLOP" in such a case. The
hooks are free to decide how large a slop it is willing to accept.
Strictly speaking, the "nonce" is not really a "nonce" anymore in
the stateless RPC mode, as it will happily take any "nonce" issued
by it (which is protected by HMAC and its secret key) as long as it
is fresh enough. The degree of this security degradation, relative
to the native protocol, is about the same as the "we make sure that
the 'git push' decided to update our refs with new objects based on
the freshest observation of our refs by making sure the values they
claim the original value of the refs they ask us to update exactly
match the current state" security is loosened to accomodate the
stateless RPC mode in the existing code without this series, so
there is no need for those who are already using smart HTTP to push
to their repositories to be alarmed any more than they already are.
In addition, the server operator can set receive.certnonceslop
configuration variable to specify how stale a nonce can be (in
seconds). When this variable is set, and if the nonce received in
the certificate that passes the HMAC check was less than that many
seconds old, hooks are given "OK" in GIT_PUSH_CERT_NONCE_STATUS
(instead of "SLOP") and the received nonce value is given in
GIT_PUSH_CERT_NONCE, which makes it easier for a simple-minded
hook to check if the certificate we received is recent enough.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In order to prevent a valid push certificate for pushing into an
repository from getting replayed in a different push operation, send
a nonce string from the receive-pack process and have the signer
include it in the push certificate. The receiving end uses an HMAC
hash of the path to the repository it serves and the current time
stamp, hashed with a secret seed (the secret seed does not have to
be per-repository but can be defined in /etc/gitconfig) to generate
the nonce, in order to ensure that a random third party cannot forge
a nonce that looks like it originated from it.
The original nonce is exported as GIT_PUSH_CERT_NONCE for the hooks
to examine and match against the value on the "nonce" header in the
certificate to notice a replay, but returned "nonce" header in the
push certificate is examined by receive-pack and the result is
exported as GIT_PUSH_CERT_NONCE_STATUS, whose value would be "OK"
if the nonce recorded in the certificate matches what we expect, so
that the hooks can more easily check.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The pre-receive and post-receive hooks were designed to be an
improvement over old style update and post-update hooks, which take
the update information on their command line and are limited by the
command line length limit. The same information is fed from the
standard input to pre/post-receive hooks instead to lift this
limitation. It has been mandatory for these new style hooks to
consume the update information fully from the standard input stream.
Otherwise, they would risk killing the receive-pack process via
SIGPIPE.
If a hook does not want to look at all the information, it is easy
to send its standard input to /dev/null (perhaps a niche use of hook
might need to know only the fact that a push was made, without
having to know what objects have been pushed to update which refs),
and this has already been done by existing hooks that are written
carefully.
However, because there is no good way to consistently fail hooks
that do not consume the input fully (a small push may result in a
short update record that may fit within the pipe buffer, to which
the receive-pack process may manage to write before the hook has a
chance to exit without reading anything, which will not result in a
death-by-SIGPIPE of receive-pack), it can lead to a hard to diagnose
"once in a blue moon" phantom failure.
Lift this "hooks must consume their input fully" mandate. A mandate
that is not enforced strictly is not helping us to catch mistakes in
hooks. If a hook has a good reason to decide the outcome of its
operation without reading the information we feed it, let it do so
as it pleases.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
