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git/serve.c

322 lines
7.4 KiB

#include "cache.h"
#include "repository.h"
#include "config.h"
#include "pkt-line.h"
#include "version.h"
#include "strvec.h"
#include "ls-refs.h"
#include "protocol-caps.h"
#include "serve.h"
#include "upload-pack.h"
static int advertise_sid = -1;
static int always_advertise(struct repository *r,
struct strbuf *value)
{
return 1;
}
static int agent_advertise(struct repository *r,
struct strbuf *value)
{
if (value)
strbuf_addstr(value, git_user_agent_sanitized());
return 1;
}
static int object_format_advertise(struct repository *r,
struct strbuf *value)
{
if (value)
strbuf_addstr(value, r->hash_algo->name);
return 1;
}
static int session_id_advertise(struct repository *r, struct strbuf *value)
{
if (advertise_sid == -1 &&
git_config_get_bool("transfer.advertisesid", &advertise_sid))
advertise_sid = 0;
if (!advertise_sid)
return 0;
if (value)
strbuf_addstr(value, trace2_session_id());
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.
* Will be provided a struct packet_reader 'request' which it 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 packet_reader *request);
};
static struct protocol_capability capabilities[] = {
{
.name = "agent",
.advertise = agent_advertise,
},
{
.name = "ls-refs",
.advertise = ls_refs_advertise,
.command = ls_refs,
},
{
.name = "fetch",
.advertise = upload_pack_advertise,
.command = upload_pack_v2,
},
{
.name = "server-option",
.advertise = always_advertise,
},
{
.name = "object-format",
.advertise = object_format_advertise,
},
{
.name = "session-id",
.advertise = session_id_advertise,
},
{
.name = "object-info",
.advertise = always_advertise,
.command = cap_object_info,
},
};
void protocol_v2_advertise_capabilities(void)
{
struct strbuf capability = STRBUF_INIT;
struct strbuf value = STRBUF_INIT;
int i;
/* serve by default supports v2 */
packet_write_fmt(1, "version 2\n");
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;
}
static int has_capability(const struct strvec *keys, const char *capability,
const char **value)
{
int i;
for (i = 0; i < keys->nr; i++) {
const char *out;
if (skip_prefix(keys->v[i], capability, &out) &&
(!*out || *out == '=')) {
if (value) {
if (*out == '=')
out++;
*value = out;
}
return 1;
}
}
return 0;
}
static void check_algorithm(struct repository *r, struct strvec *keys)
{
int client = GIT_HASH_SHA1, server = hash_algo_by_ptr(r->hash_algo);
const char *algo_name;
if (has_capability(keys, "object-format", &algo_name)) {
client = hash_algo_by_name(algo_name);
if (client == GIT_HASH_UNKNOWN)
die("unknown object format '%s'", algo_name);
}
if (client != server)
die("mismatched object format: server %s; client %s\n",
r->hash_algo->name, hash_algos[client].name);
}
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 strvec keys = STRVEC_INIT;
struct protocol_capability *command = NULL;
const char *client_sid;
packet_reader_init(&reader, 0, NULL, 0,
PACKET_READ_CHOMP_NEWLINE |
PACKET_READ_GENTLE_ON_EOF |
PACKET_READ_DIE_ON_ERR_PACKET);
/*
* 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_GENTLE_ON_EOF;
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))
strvec_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.nr)
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;
case PACKET_READ_RESPONSE_END:
BUG("unexpected response end packet");
}
}
if (!command)
die("no command requested");
check_algorithm(the_repository, &keys);
if (has_capability(&keys, "session-id", &client_sid))
trace2_data_string("transfer", NULL, "client-sid", client_sid);
command->command(the_repository, &reader);
strvec_clear(&keys);
return 0;
}
void protocol_v2_serve_loop(int stateless_rpc)
{
if (!stateless_rpc)
protocol_v2_advertise_capabilities();
/*
* If stateless-rpc was requested then exit after
* a single request/response exchange
*/
if (stateless_rpc) {
process_request();
} else {
for (;;)
if (process_request())
break;
}
}