Adding upstream version 1:2.39.2.upstream/1%2.39.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 329 insertions, 0 deletions

diff --git a/serve.c b/serve.c
new file mode 100644
index 0000000..733347f
--- /dev/null
+++ b/serve.c
@@ -0,0 +1,329 @@
+#include "cache.h"
+#include "repository.h"
+#include "config.h"
+#include "pkt-line.h"
+#include "version.h"
+#include "ls-refs.h"
+#include "protocol-caps.h"
+#include "serve.h"
+#include "upload-pack.h"
+
+static int advertise_sid = -1;
+static int client_hash_algo = GIT_HASH_SHA1;
+
+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 void object_format_receive(struct repository *r,
+				  const char *algo_name)
+{
+	if (!algo_name)
+		die("object-format capability requires an argument");
+
+	client_hash_algo = hash_algo_by_name(algo_name);
+	if (client_hash_algo == GIT_HASH_UNKNOWN)
+		die("unknown object format '%s'", algo_name);
+}
+
+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;
+}
+
+static void session_id_receive(struct repository *r,
+			       const char *client_sid)
+{
+	if (!client_sid)
+		client_sid = "";
+	trace2_data_string("transfer", NULL, "client-sid", client_sid);
+}
+
+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);
+
+	/*
+	 * Function called when a client requests the capability as a
+	 * non-command. This may be NULL if the capability does nothing.
+	 *
+	 * For a capability of the form "foo=bar", the value string points to
+	 * the content after the "=" (i.e., "bar"). For simple capabilities
+	 * (just "foo"), it is NULL.
+	 */
+	void (*receive)(struct repository *r, const char *value);
+};
+
+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,
+		.receive = object_format_receive,
+	},
+	{
+		.name = "session-id",
+		.advertise = session_id_advertise,
+		.receive = session_id_receive,
+	},
+	{
+		.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, const char **value)
+{
+	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))
+			continue;
+		if (!*out) {
+			*value = NULL;
+			return c;
+		}
+		if (*out++ == '=') {
+			*value = out;
+			return c;
+		}
+	}
+
+	return NULL;
+}
+
+static int receive_client_capability(const char *key)
+{
+	const char *value;
+	const struct protocol_capability *c = get_capability(key, &value);
+
+	if (!c || c->command || !c->advertise(the_repository, NULL))
+		return 0;
+
+	if (c->receive)
+		c->receive(the_repository, value);
+	return 1;
+}
+
+static int parse_command(const char *key, struct protocol_capability **command)
+{
+	const char *out;
+
+	if (skip_prefix(key, "command=", &out)) {
+		const char *value;
+		struct protocol_capability *cmd = get_capability(out, &value);
+
+		if (*command)
+			die("command '%s' requested after already requesting command '%s'",
+			    out, (*command)->name);
+		if (!cmd || !cmd->advertise(the_repository, NULL) || !cmd->command || value)
+			die("invalid command '%s'", out);
+
+		*command = cmd;
+		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;
+	int seen_capability_or_command = 0;
+	struct protocol_capability *command = NULL;
+
+	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:
+			if (parse_command(reader.line, &command) ||
+			    receive_client_capability(reader.line))
+				seen_capability_or_command = 1;
+			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 (!seen_capability_or_command)
+				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");
+
+	if (client_hash_algo != hash_algo_by_ptr(the_repository->hash_algo))
+		die("mismatched object format: server %s; client %s\n",
+		    the_repository->hash_algo->name,
+		    hash_algos[client_hash_algo].name);
+
+	command->command(the_repository, &reader);
+
+	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;
+	}
+}