diff options
Diffstat (limited to 'serve.c')
| -rw-r--r-- | serve.c | 306 |
1 files changed, 306 insertions, 0 deletions
@@ -0,0 +1,306 @@ +#include "cache.h" +#include "repository.h" +#include "config.h" +#include "pkt-line.h" +#include "version.h" +#include "strvec.h" +#include "ls-refs.h" +#include "serve.h" +#include "upload-pack.h" + +static int advertise_sid; + +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) + 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. + * 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 strvec *keys, + struct packet_reader *request); +}; + +static struct protocol_capability capabilities[] = { + { "agent", agent_advertise, NULL }, + { "ls-refs", always_advertise, ls_refs }, + { "fetch", upload_pack_advertise, upload_pack_v2 }, + { "server-option", always_advertise, NULL }, + { "object-format", object_format_advertise, NULL }, + { "session-id", session_id_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 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 stateless separator 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, &keys, &reader); + + strvec_clear(&keys); + return 0; +} + +/* Main serve loop for protocol version 2 */ +void serve(struct serve_options *options) +{ + git_config_get_bool("transfer.advertisesid", &advertise_sid); + + 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; + } +} |