diff options
Diffstat (limited to 'Documentation/technical/pack-protocol.txt')
| -rw-r--r-- | Documentation/technical/pack-protocol.txt | 121 |
1 files changed, 88 insertions, 33 deletions
diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt index b898e97988..c6977bbc5a 100644 --- a/Documentation/technical/pack-protocol.txt +++ b/Documentation/technical/pack-protocol.txt @@ -1,11 +1,11 @@ Packfile transfer protocols =========================== -Git supports transferring data in packfiles over the ssh://, git:// and +Git supports transferring data in packfiles over the ssh://, git://, http:// and file:// transports. There exist two sets of protocols, one for pushing data from a client to a server and another for fetching data from a -server to a client. All three transports (ssh, git, file) use the same -protocol to transfer data. +server to a client. The three transports (ssh, git, file) use the same +protocol to transfer data. http is documented in http-protocol.txt. The processes invoked in the canonical Git implementation are 'upload-pack' on the server side and 'fetch-pack' on the client side for fetching data; @@ -14,6 +14,14 @@ data. The protocol functions to have a server tell a client what is currently on the server, then for the two to negotiate the smallest amount of data to send in order to fully update one or the other. +pkt-line Format +--------------- + +The descriptions below build on the pkt-line format described in +protocol-common.txt. When the grammar indicate `PKT-LINE(...)`, unless +otherwise noted the usual pkt-line LF rules apply: the sender SHOULD +include a LF, but the receiver MUST NOT complain if it is not present. + Transports ---------- There are three transports over which the packfile protocol is @@ -143,9 +151,6 @@ with the object name that each reference currently points to. 003fe92df48743b7bc7d26bcaabfddde0a1e20cae47c refs/tags/v1.0^{} 0000 -Server SHOULD terminate each non-flush line using LF ("\n") terminator; -client MUST NOT complain if there is no terminator. - The returned response is a pkt-line stream describing each ref and its current value. The stream MUST be sorted by name according to the C locale ordering. @@ -161,18 +166,21 @@ MUST peel the ref if it's an annotated tag. ---- advertised-refs = (no-refs / list-of-refs) + *shallow flush-pkt no-refs = PKT-LINE(zero-id SP "capabilities^{}" - NUL capability-list LF) + NUL capability-list) list-of-refs = first-ref *other-ref first-ref = PKT-LINE(obj-id SP refname - NUL capability-list LF) + NUL capability-list) other-ref = PKT-LINE(other-tip / other-peeled) - other-tip = obj-id SP refname LF - other-peeled = obj-id SP refname "^{}" LF + other-tip = obj-id SP refname + other-peeled = obj-id SP refname "^{}" + + shallow = PKT-LINE("shallow" SP obj-id) capability-list = capability *(SP capability) capability = 1*(LC_ALPHA / DIGIT / "-" / "_") @@ -209,12 +217,12 @@ out of what the server said it could do with the first 'want' line. want-list = first-want *additional-want - shallow-line = PKT_LINE("shallow" SP obj-id) + shallow-line = PKT-LINE("shallow" SP obj-id) - depth-request = PKT_LINE("deepen" SP depth) + depth-request = PKT-LINE("deepen" SP depth) - first-want = PKT-LINE("want" SP obj-id SP capability-list LF) - additional-want = PKT-LINE("want" SP obj-id LF) + first-want = PKT-LINE("want" SP obj-id SP capability-list) + additional-want = PKT-LINE("want" SP obj-id) depth = 1*DIGIT ---- @@ -234,10 +242,10 @@ The client now sends the maximum commit history depth it wants for this transaction, which is the number of commits it wants from the tip of the history, if any, as a 'deepen' line. A depth of 0 is the same as not making a depth request. The client does not want to receive -any commits beyond this depth, nor objects needed only to complete -those commits. Commits whose parents are not received as a result are -defined as shallow and marked as such in the server. This information -is sent back to the client in the next step. +any commits beyond this depth, nor does it want objects needed only to +complete those commits. Commits whose parents are not received as a +result are defined as shallow and marked as such in the server. This +information is sent back to the client in the next step. Once all the 'want's and 'shallow's (and optional 'deepen') are transferred, clients MUST send a flush-pkt, to tell the server side @@ -281,7 +289,7 @@ so that there is always a block of 32 "in-flight on the wire" at a time. compute-end have-list = *have-line - have-line = PKT-LINE("have" SP obj-id LF) + have-line = PKT-LINE("have" SP obj-id) compute-end = flush-pkt / PKT-LINE("done") ---- @@ -335,7 +343,8 @@ during a prior round. This helps to ensure that at least one common ancestor is found before we give up entirely. Once the 'done' line is read from the client, the server will either -send a final 'ACK obj-id' or it will send a 'NAK'. The server only sends +send a final 'ACK obj-id' or it will send a 'NAK'. 'obj-id' is the object +name of the last commit determined to be common. The server only sends ACK after 'done' if there is at least one common base and multi_ack or multi_ack_detailed is enabled. The server always sends NAK after 'done' if there is no common base found. @@ -344,10 +353,10 @@ Then the server will start sending its packfile data. ---- server-response = *ack_multi ack / nak - ack_multi = PKT-LINE("ACK" SP obj-id ack_status LF) + ack_multi = PKT-LINE("ACK" SP obj-id ack_status) ack_status = "continue" / "common" / "ready" - ack = PKT-LINE("ACK SP obj-id LF) - nak = PKT-LINE("NAK" LF) + ack = PKT-LINE("ACK" SP obj-id) + nak = PKT-LINE("NAK") ---- A simple clone may look like this (with no 'have' lines): @@ -461,10 +470,12 @@ contain all the objects that the server will need to complete the new references. ---- - update-request = command-list [pack-file] + update-request = *shallow ( command-list | push-cert ) [packfile] - command-list = PKT-LINE(command NUL capability-list LF) - *PKT-LINE(command LF) + shallow = PKT-LINE("shallow" SP obj-id) + + command-list = PKT-LINE(command NUL capability-list) + *PKT-LINE(command) flush-pkt command = create / delete / update @@ -475,17 +486,32 @@ references. old-id = obj-id new-id = obj-id - pack-file = "PACK" 28*(OCTET) + push-cert = PKT-LINE("push-cert" NUL capability-list LF) + PKT-LINE("certificate version 0.1" LF) + PKT-LINE("pusher" SP ident LF) + PKT-LINE("pushee" SP url LF) + PKT-LINE("nonce" SP nonce LF) + PKT-LINE(LF) + *PKT-LINE(command LF) + *PKT-LINE(gpg-signature-lines LF) + PKT-LINE("push-cert-end" LF) + + packfile = "PACK" 28*(OCTET) ---- If the receiving end does not support delete-refs, the sending end MUST NOT ask for delete command. -The pack-file MUST NOT be sent if the only command used is 'delete'. +If the receiving end does not support push-cert, the sending end +MUST NOT send a push-cert command. When a push-cert command is +sent, command-list MUST NOT be sent; the commands recorded in the +push certificate is used instead. + +The packfile MUST NOT be sent if the only command used is 'delete'. -A pack-file MUST be sent if either create or update command is used, +A packfile MUST be sent if either create or update command is used, even if the server already has all the necessary objects. In this -case the client MUST send an empty pack-file. The only time this +case the client MUST send an empty packfile. The only time this is likely to happen is if the client is creating a new branch or a tag that points to an existing obj-id. @@ -495,6 +521,35 @@ was being processed (the obj-id is still the same as the old-id), and it will run any update hooks to make sure that the update is acceptable. If all of that is fine, the server will then update the references. +Push Certificate +---------------- + +A push certificate begins with a set of header lines. After the +header and an empty line, the protocol commands follow, one per +line. Note that the the trailing LF in push-cert PKT-LINEs is _not_ +optional; it must be present. + +Currently, the following header fields are defined: + +`pusher` ident:: + Identify the GPG key in "Human Readable Name <email@address>" + format. + +`pushee` url:: + The repository URL (anonymized, if the URL contains + authentication material) the user who ran `git push` + intended to push into. + +`nonce` nonce:: + The 'nonce' string the receiving repository asked the + pushing user to include in the certificate, to prevent + replay attacks. + +The GPG signature lines are a detached signature for the contents +recorded in the push certificate before the signature block begins. +The detached signature is used to certify that the commands were +given by the pusher, who must be the signer. + Report Status ------------- @@ -511,12 +566,12 @@ update was successful, or 'ng [refname] [error]' if the update was not. 1*(command-status) flush-pkt - unpack-status = PKT-LINE("unpack" SP unpack-result LF) + unpack-status = PKT-LINE("unpack" SP unpack-result) unpack-result = "ok" / error-msg command-status = command-ok / command-fail - command-ok = PKT-LINE("ok" SP refname LF) - command-fail = PKT-LINE("ng" SP refname SP error-msg LF) + command-ok = PKT-LINE("ok" SP refname) + command-fail = PKT-LINE("ng" SP refname SP error-msg) error-msg = 1*(OCTECT) ; where not "ok" ---- |