diff options
| -rw-r--r-- | .gitignore | 1 | ||||
| -rw-r--r-- | Documentation/Makefile | 1 | ||||
| -rw-r--r-- | Documentation/technical/protocol-v2.txt | 170 | ||||
| -rw-r--r-- | Makefile | 2 | ||||
| -rw-r--r-- | builtin.h | 1 | ||||
| -rw-r--r-- | builtin/serve.c | 30 | ||||
| -rw-r--r-- | git.c | 1 | ||||
| -rw-r--r-- | serve.c | 247 | ||||
| -rw-r--r-- | serve.h | 15 | ||||
| -rwxr-xr-x | t/t5701-git-serve.sh | 60 |
10 files changed, 528 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore index 833ef3b0b7..2d0450c262 100644 --- a/.gitignore +++ b/.gitignore @@ -140,6 +140,7 @@ /git-rm /git-send-email /git-send-pack +/git-serve /git-sh-i18n /git-sh-i18n--envsubst /git-sh-setup diff --git a/Documentation/Makefile b/Documentation/Makefile index 4ae9ba5c86..b105775acd 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -77,6 +77,7 @@ TECH_DOCS += technical/pack-heuristics TECH_DOCS += technical/pack-protocol TECH_DOCS += technical/protocol-capabilities TECH_DOCS += technical/protocol-common +TECH_DOCS += technical/protocol-v2 TECH_DOCS += technical/racy-git TECH_DOCS += technical/send-pack-pipeline TECH_DOCS += technical/shallow diff --git a/Documentation/technical/protocol-v2.txt b/Documentation/technical/protocol-v2.txt new file mode 100644 index 0000000000..270b28f364 --- /dev/null +++ b/Documentation/technical/protocol-v2.txt @@ -0,0 +1,170 @@ + Git Wire Protocol, Version 2 +============================== + +This document presents a specification for a version 2 of Git's wire +protocol. Protocol v2 will improve upon v1 in the following ways: + + * Instead of multiple service names, multiple commands will be + supported by a single service + * Easily extendable as capabilities are moved into their own section + of the protocol, no longer being hidden behind a NUL byte and + limited by the size of a pkt-line + * Separate out other information hidden behind NUL bytes (e.g. agent + string as a capability and symrefs can be requested using 'ls-refs') + * Reference advertisement will be omitted unless explicitly requested + * ls-refs command to explicitly request some refs + * Designed with http and stateless-rpc in mind. With clear flush + semantics the http remote helper can simply act as a proxy + +In protocol v2 communication is command oriented. When first contacting a +server a list of capabilities will advertised. Some of these capabilities +will be commands which a client can request be executed. Once a command +has completed, a client can reuse the connection and request that other +commands be executed. + + Packet-Line Framing +--------------------- + +All communication is done using packet-line framing, just as in v1. See +`Documentation/technical/pack-protocol.txt` and +`Documentation/technical/protocol-common.txt` for more information. + +In protocol v2 these special packets will have the following semantics: + + * '0000' Flush Packet (flush-pkt) - indicates the end of a message + * '0001' Delimiter Packet (delim-pkt) - separates sections of a message + + Initial Client Request +------------------------ + +In general a client can request to speak protocol v2 by sending +`version=2` through the respective side-channel for the transport being +used which inevitably sets `GIT_PROTOCOL`. More information can be +found in `pack-protocol.txt` and `http-protocol.txt`. In all cases the +response from the server is the capability advertisement. + + Git Transport +~~~~~~~~~~~~~~~ + +When using the git:// transport, you can request to use protocol v2 by +sending "version=2" as an extra parameter: + + 003egit-upload-pack /project.git\0host=myserver.com\0\0version=2\0 + + SSH and File Transport +~~~~~~~~~~~~~~~~~~~~~~~~ + +When using either the ssh:// or file:// transport, the GIT_PROTOCOL +environment variable must be set explicitly to include "version=2". + + HTTP Transport +~~~~~~~~~~~~~~~~ + +When using the http:// or https:// transport a client makes a "smart" +info/refs request as described in `http-protocol.txt` and requests that +v2 be used by supplying "version=2" in the `Git-Protocol` header. + + C: Git-Protocol: version=2 + C: + C: GET $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0 + +A v2 server would reply: + + S: 200 OK + S: <Some headers> + S: ... + S: + S: 000eversion 2\n + S: <capability-advertisement> + +Subsequent requests are then made directly to the service +`$GIT_URL/git-upload-pack`. (This works the same for git-receive-pack). + + Capability Advertisement +-------------------------- + +A server which decides to communicate (based on a request from a client) +using protocol version 2, notifies the client by sending a version string +in its initial response followed by an advertisement of its capabilities. +Each capability is a key with an optional value. Clients must ignore all +unknown keys. Semantics of unknown values are left to the definition of +each key. Some capabilities will describe commands which can be requested +to be executed by the client. + + capability-advertisement = protocol-version + capability-list + flush-pkt + + protocol-version = PKT-LINE("version 2" LF) + capability-list = *capability + capability = PKT-LINE(key[=value] LF) + + key = 1*(ALPHA | DIGIT | "-_") + value = 1*(ALPHA | DIGIT | " -_.,?\/{}[]()<>!@#$%^&*+=:;") + + Command Request +----------------- + +After receiving the capability advertisement, a client can then issue a +request to select the command it wants with any particular capabilities +or arguments. There is then an optional section where the client can +provide any command specific parameters or queries. Only a single +command can be requested at a time. + + request = empty-request | command-request + empty-request = flush-pkt + command-request = command + capability-list + [command-args] + flush-pkt + command = PKT-LINE("command=" key LF) + command-args = delim-pkt + *command-specific-arg + + command-specific-args are packet line framed arguments defined by + each individual command. + +The server will then check to ensure that the client's request is +comprised of a valid command as well as valid capabilities which were +advertised. If the request is valid the server will then execute the +command. A server MUST wait till it has received the client's entire +request before issuing a response. The format of the response is +determined by the command being executed, but in all cases a flush-pkt +indicates the end of the response. + +When a command has finished, and the client has received the entire +response from the server, a client can either request that another +command be executed or can terminate the connection. A client may +optionally send an empty request consisting of just a flush-pkt to +indicate that no more requests will be made. + + Capabilities +-------------- + +There are two different types of capabilities: normal capabilities, +which can be used to to convey information or alter the behavior of a +request, and commands, which are the core actions that a client wants to +perform (fetch, push, etc). + +Protocol version 2 is stateless by default. This means that all commands +must only last a single round and be stateless from the perspective of the +server side, unless the client has requested a capability indicating that +state should be maintained by the server. Clients MUST NOT require state +management on the server side in order to function correctly. This +permits simple round-robin load-balancing on the server side, without +needing to worry about state management. + + agent +~~~~~~~ + +The server can advertise the `agent` capability with a value `X` (in the +form `agent=X`) to notify the client that the server is running version +`X`. The client may optionally send its own agent string by including +the `agent` capability with a value `Y` (in the form `agent=Y`) in its +request to the server (but it MUST NOT do so if the server did not +advertise the agent capability). The `X` and `Y` strings may contain any +printable ASCII characters except space (i.e., the byte range 32 < x < +127), and are typically of the form "package/version" (e.g., +"git/1.8.3.1"). The agent strings are purely informative for statistics +and debugging purposes, and MUST NOT be used to programmatically assume +the presence or absence of particular features. @@ -876,6 +876,7 @@ LIB_OBJS += revision.o LIB_OBJS += run-command.o LIB_OBJS += send-pack.o LIB_OBJS += sequencer.o +LIB_OBJS += serve.o LIB_OBJS += server-info.o LIB_OBJS += setup.o LIB_OBJS += sha1-array.o @@ -1009,6 +1010,7 @@ BUILTIN_OBJS += builtin/rev-parse.o BUILTIN_OBJS += builtin/revert.o BUILTIN_OBJS += builtin/rm.o BUILTIN_OBJS += builtin/send-pack.o +BUILTIN_OBJS += builtin/serve.o BUILTIN_OBJS += builtin/shortlog.o BUILTIN_OBJS += builtin/show-branch.o BUILTIN_OBJS += builtin/show-ref.o @@ -215,6 +215,7 @@ extern int cmd_rev_parse(int argc, const char **argv, const char *prefix); extern int cmd_revert(int argc, const char **argv, const char *prefix); extern int cmd_rm(int argc, const char **argv, const char *prefix); extern int cmd_send_pack(int argc, const char **argv, const char *prefix); +extern int cmd_serve(int argc, const char **argv, const char *prefix); extern int cmd_shortlog(int argc, const char **argv, const char *prefix); extern int cmd_show(int argc, const char **argv, const char *prefix); extern int cmd_show_branch(int argc, const char **argv, const char *prefix); diff --git a/builtin/serve.c b/builtin/serve.c new file mode 100644 index 0000000000..d3fd240bb3 --- /dev/null +++ b/builtin/serve.c @@ -0,0 +1,30 @@ +#include "cache.h" +#include "builtin.h" +#include "parse-options.h" +#include "serve.h" + +static char const * const serve_usage[] = { + N_("git serve [<options>]"), + NULL +}; + +int cmd_serve(int argc, const char **argv, const char *prefix) +{ + struct serve_options opts = SERVE_OPTIONS_INIT; + + struct option options[] = { + OPT_BOOL(0, "stateless-rpc", &opts.stateless_rpc, + N_("quit after a single request/response exchange")), + OPT_BOOL(0, "advertise-capabilities", &opts.advertise_capabilities, + N_("exit immediately after advertising capabilities")), + OPT_END() + }; + + /* ignore all unknown cmdline switches for now */ + argc = parse_options(argc, argv, prefix, options, serve_usage, + PARSE_OPT_KEEP_DASHDASH | + PARSE_OPT_KEEP_UNKNOWN); + serve(&opts); + + return 0; +} @@ -461,6 +461,7 @@ static struct cmd_struct commands[] = { { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE }, { "rm", cmd_rm, RUN_SETUP }, { "send-pack", cmd_send_pack, RUN_SETUP }, + { "serve", cmd_serve, RUN_SETUP }, { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER }, { "show", cmd_show, RUN_SETUP }, { "show-branch", cmd_show_branch, RUN_SETUP }, diff --git a/serve.c b/serve.c new file mode 100644 index 0000000000..7ddcba9003 --- /dev/null +++ b/serve.c @@ -0,0 +1,247 @@ +#include "cache.h" +#include "repository.h" +#include "config.h" +#include "pkt-line.h" +#include "version.h" +#include "argv-array.h" +#include "serve.h" + +static int agent_advertise(struct repository *r, + struct strbuf *value) +{ + if (value) + strbuf_addstr(value, git_user_agent_sanitized()); + return 1; +} + +struct protocol_capability { + /* + * The name of the capability. The server uses this name when + * advertising this capability, and the client uses this name to + * specify this capability. + */ + const char *name; + + /* + * Function queried to see if a capability should be advertised. + * Optionally a value can be specified by adding it to 'value'. + * If a value is added to 'value', the server will advertise this + * capability as "<name>=<value>" instead of "<name>". + */ + int (*advertise)(struct repository *r, struct strbuf *value); + + /* + * Function called when a client requests the capability as a command. + * The function will be provided the capabilities requested via 'keys' + * as well as a struct packet_reader 'request' which the command should + * use to read the command specific part of the request. Every command + * MUST read until a flush packet is seen before sending a response. + * + * This field should be NULL for capabilities which are not commands. + */ + int (*command)(struct repository *r, + struct argv_array *keys, + struct packet_reader *request); +}; + +static struct protocol_capability capabilities[] = { + { "agent", agent_advertise, NULL }, +}; + +static void advertise_capabilities(void) +{ + struct strbuf capability = STRBUF_INIT; + struct strbuf value = STRBUF_INIT; + int i; + + for (i = 0; i < ARRAY_SIZE(capabilities); i++) { + struct protocol_capability *c = &capabilities[i]; + + if (c->advertise(the_repository, &value)) { + strbuf_addstr(&capability, c->name); + + if (value.len) { + strbuf_addch(&capability, '='); + strbuf_addbuf(&capability, &value); + } + + strbuf_addch(&capability, '\n'); + packet_write(1, capability.buf, capability.len); + } + + strbuf_reset(&capability); + strbuf_reset(&value); + } + + packet_flush(1); + strbuf_release(&capability); + strbuf_release(&value); +} + +static struct protocol_capability *get_capability(const char *key) +{ + int i; + + if (!key) + return NULL; + + for (i = 0; i < ARRAY_SIZE(capabilities); i++) { + struct protocol_capability *c = &capabilities[i]; + const char *out; + if (skip_prefix(key, c->name, &out) && (!*out || *out == '=')) + return c; + } + + return NULL; +} + +static int is_valid_capability(const char *key) +{ + const struct protocol_capability *c = get_capability(key); + + return c && c->advertise(the_repository, NULL); +} + +static int is_command(const char *key, struct protocol_capability **command) +{ + const char *out; + + if (skip_prefix(key, "command=", &out)) { + struct protocol_capability *cmd = get_capability(out); + + if (*command) + die("command '%s' requested after already requesting command '%s'", + out, (*command)->name); + if (!cmd || !cmd->advertise(the_repository, NULL) || !cmd->command) + die("invalid command '%s'", out); + + *command = cmd; + return 1; + } + + return 0; +} + +int has_capability(const struct argv_array *keys, const char *capability, + const char **value) +{ + int i; + for (i = 0; i < keys->argc; i++) { + const char *out; + if (skip_prefix(keys->argv[i], capability, &out) && + (!*out || *out == '=')) { + if (value) { + if (*out == '=') + out++; + *value = out; + } + return 1; + } + } + + return 0; +} + +enum request_state { + PROCESS_REQUEST_KEYS, + PROCESS_REQUEST_DONE, +}; + +static int process_request(void) +{ + enum request_state state = PROCESS_REQUEST_KEYS; + struct packet_reader reader; + struct argv_array keys = ARGV_ARRAY_INIT; + struct protocol_capability *command = NULL; + + packet_reader_init(&reader, 0, NULL, 0, + PACKET_READ_CHOMP_NEWLINE | + PACKET_READ_GENTLE_ON_EOF); + + /* + * Check to see if the client closed their end before sending another + * request. If so we can terminate the connection. + */ + if (packet_reader_peek(&reader) == PACKET_READ_EOF) + return 1; + reader.options = PACKET_READ_CHOMP_NEWLINE; + + while (state != PROCESS_REQUEST_DONE) { + switch (packet_reader_peek(&reader)) { + case PACKET_READ_EOF: + BUG("Should have already died when seeing EOF"); + case PACKET_READ_NORMAL: + /* collect request; a sequence of keys and values */ + if (is_command(reader.line, &command) || + is_valid_capability(reader.line)) + argv_array_push(&keys, reader.line); + else + die("unknown capability '%s'", reader.line); + + /* Consume the peeked line */ + packet_reader_read(&reader); + break; + case PACKET_READ_FLUSH: + /* + * If no command and no keys were given then the client + * wanted to terminate the connection. + */ + if (!keys.argc) + return 1; + + /* + * The flush packet isn't consume here like it is in + * the other parts of this switch statement. This is + * so that the command can read the flush packet and + * see the end of the request in the same way it would + * if command specific arguments were provided after a + * delim packet. + */ + state = PROCESS_REQUEST_DONE; + break; + case PACKET_READ_DELIM: + /* Consume the peeked line */ + packet_reader_read(&reader); + + state = PROCESS_REQUEST_DONE; + break; + } + } + + if (!command) + die("no command requested"); + + command->command(the_repository, &keys, &reader); + + argv_array_clear(&keys); + return 0; +} + +/* Main serve loop for protocol version 2 */ +void serve(struct serve_options *options) +{ + if (options->advertise_capabilities || !options->stateless_rpc) { + /* serve by default supports v2 */ + packet_write_fmt(1, "version 2\n"); + + advertise_capabilities(); + /* + * If only the list of capabilities was requested exit + * immediately after advertising capabilities + */ + if (options->advertise_capabilities) + return; + } + + /* + * If stateless-rpc was requested then exit after + * a single request/response exchange + */ + if (options->stateless_rpc) { + process_request(); + } else { + for (;;) + if (process_request()) + break; + } +} diff --git a/serve.h b/serve.h new file mode 100644 index 0000000000..fe65ba9f46 --- /dev/null +++ b/serve.h @@ -0,0 +1,15 @@ +#ifndef SERVE_H +#define SERVE_H + +struct argv_array; +extern int has_capability(const struct argv_array *keys, const char *capability, + const char **value); + +struct serve_options { + unsigned advertise_capabilities; + unsigned stateless_rpc; +}; +#define SERVE_OPTIONS_INIT { 0 } +extern void serve(struct serve_options *options); + +#endif /* SERVE_H */ diff --git a/t/t5701-git-serve.sh b/t/t5701-git-serve.sh new file mode 100755 index 0000000000..affbad097d --- /dev/null +++ b/t/t5701-git-serve.sh @@ -0,0 +1,60 @@ +#!/bin/sh + +test_description='test git-serve and server commands' + +. ./test-lib.sh + +test_expect_success 'test capability advertisement' ' + cat >expect <<-EOF && + version 2 + agent=git/$(git version | cut -d" " -f3) + 0000 + EOF + + git serve --advertise-capabilities >out && + test-pkt-line unpack <out >actual && + test_cmp actual expect +' + +test_expect_success 'stateless-rpc flag does not list capabilities' ' + # Empty request + test-pkt-line pack >in <<-EOF && + 0000 + EOF + git serve --stateless-rpc >out <in && + test_must_be_empty out && + + # EOF + git serve --stateless-rpc >out && + test_must_be_empty out +' + +test_expect_success 'request invalid capability' ' + test-pkt-line pack >in <<-EOF && + foobar + 0000 + EOF + test_must_fail git serve --stateless-rpc 2>err <in && + test_i18ngrep "unknown capability" err +' + +test_expect_success 'request with no command' ' + test-pkt-line pack >in <<-EOF && + agent=git/test + 0000 + EOF + test_must_fail git serve --stateless-rpc 2>err <in && + test_i18ngrep "no command requested" err +' + +test_expect_success 'request invalid command' ' + test-pkt-line pack >in <<-EOF && + command=foo + agent=git/test + 0000 + EOF + test_must_fail git serve --stateless-rpc 2>err <in && + test_i18ngrep "invalid command" err +' + +test_done |