Teach remote-curl the 'stateless-connect' command which is used to
establish a stateless connection with servers which support protocol
version 2. This allows remote-curl to act as a proxy, allowing the git
client to communicate natively with a remote end, simply using
remote-curl as a pass through to convert requests to http.
Signed-off-by: Brandon Williams <bmw...@google.com>
---
remote-curl.c | 207 ++++++++++++++++++++++++++++++++++++++++-
t/t5702-protocol-v2.sh | 45 +++++++++
2 files changed, 251 insertions(+), 1 deletion(-)
diff --git a/remote-curl.c b/remote-curl.c
index 66a53f74bb..87f5b77b29 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -188,7 +188,12 @@ static struct ref *parse_git_refs(struct discovery *heads,
int for_push)
heads->version = discover_version(&reader);
switch (heads->version) {
case protocol_v2:
- die("support for protocol v2 not implemented yet");
+ /*
+ * Do nothing. This isn't a list of refs but rather a
+ * capability advertisement. Client would have run
+ * 'stateless-connect' so we'll dump this capability listing
+ * and let them request the refs themselves.
+ */
break;
case protocol_v1:
case protocol_v0:
@@ -1085,6 +1090,202 @@ static void parse_push(struct strbuf *buf)
free(specs);
}
+/*
+ * Used to represent the state of a connection to an HTTP server when
+ * communicating using git's wire-protocol version 2.
+ */
+struct proxy_state {
+ char *service_name;
+ char *service_url;
+ struct curl_slist *headers;
+ struct strbuf request_buffer;
+ int in;
+ int out;
+ struct packet_reader reader;
+ size_t pos;
+ int seen_flush;
+};
+
+static void proxy_state_init(struct proxy_state *p, const char *service_name,
+ enum protocol_version version)
+{
+ struct strbuf buf = STRBUF_INIT;
+
+ memset(p, 0, sizeof(*p));
+ p->service_name = xstrdup(service_name);
+
+ p->in = 0;
+ p->out = 1;
+ strbuf_init(&p->request_buffer, 0);
+
+ strbuf_addf(&buf, "%s%s", url.buf, p->service_name);
+ p->service_url = strbuf_detach(&buf, NULL);
+
+ p->headers = http_copy_default_headers();
+
+ strbuf_addf(&buf, "Content-Type: application/x-%s-request",
p->service_name);
+ p->headers = curl_slist_append(p->headers, buf.buf);
+ strbuf_reset(&buf);
+
+ strbuf_addf(&buf, "Accept: application/x-%s-result", p->service_name);
+ p->headers = curl_slist_append(p->headers, buf.buf);
+ strbuf_reset(&buf);
+
+ p->headers = curl_slist_append(p->headers, "Transfer-Encoding:
chunked");
+
+ /* Add the Git-Protocol header */
+ if (get_protocol_http_header(version, &buf))
+ p->headers = curl_slist_append(p->headers, buf.buf);
+
+ packet_reader_init(&p->reader, p->in, NULL, 0,
+ PACKET_READ_GENTLE_ON_EOF);
+
+ strbuf_release(&buf);
+}
+
+static void proxy_state_clear(struct proxy_state *p)
+{
+ free(p->service_name);
+ free(p->service_url);
+ curl_slist_free_all(p->headers);
+ strbuf_release(&p->request_buffer);
+}
+
+/*
+ * CURLOPT_READFUNCTION callback function.
+ * Attempts to copy over a single packet-line at a time into the
+ * curl provided buffer.
+ */
+static size_t proxy_in(char *buffer, size_t eltsize,
+ size_t nmemb, void *userdata)
+{
+ size_t max;
+ struct proxy_state *p = userdata;
+ size_t avail = p->request_buffer.len - p->pos;
+
+
+ if (eltsize != 1)
+ BUG("curl read callback called with size = %"PRIuMAX" != 1",
+ (uintmax_t)eltsize);
+ max = nmemb;
+
+ if (!avail) {
+ if (p->seen_flush) {
+ p->seen_flush = 0;
+ return 0;
+ }
+
+ strbuf_reset(&p->request_buffer);
+ switch (packet_reader_read(&p->reader)) {
+ case PACKET_READ_EOF:
+ die("unexpected EOF when reading from parent process");
+ case PACKET_READ_NORMAL:
+ packet_buf_write_len(&p->request_buffer, p->reader.line,
+ p->reader.pktlen);
+ break;
+ case PACKET_READ_DELIM:
+ packet_buf_delim(&p->request_buffer);
+ break;
+ case PACKET_READ_FLUSH:
+ packet_buf_flush(&p->request_buffer);
+ p->seen_flush = 1;
+ break;
+ }
+ p->pos = 0;
+ avail = p->request_buffer.len;
+ }
+
+ if (max < avail)
+ avail = max;
+ memcpy(buffer, p->request_buffer.buf + p->pos, avail);
+ p->pos += avail;
+ return avail;
+}
+
+static size_t proxy_out(char *buffer, size_t eltsize,
+ size_t nmemb, void *userdata)
+{
+ size_t size;
+ struct proxy_state *p = userdata;
+
+ if (eltsize != 1)
+ BUG("curl read callback called with size = %"PRIuMAX" != 1",
+ (uintmax_t)eltsize);
+ size = nmemb;
+
+ write_or_die(p->out, buffer, size);
+ return size;
+}
+
+/* Issues a request to the HTTP server configured in `p` */
+static int proxy_request(struct proxy_state *p)
+{
+ struct active_request_slot *slot;
+
+ slot = get_active_slot();
+
+ curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
+ curl_easy_setopt(slot->curl, CURLOPT_POST, 1);
+ curl_easy_setopt(slot->curl, CURLOPT_URL, p->service_url);
+ curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, p->headers);
+
+ /* Setup function to read request from client */
+ curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, proxy_in);
+ curl_easy_setopt(slot->curl, CURLOPT_READDATA, p);
+
+ /* Setup function to write server response to client */
+ curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, proxy_out);
+ curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, p);
+
+ if (run_slot(slot, NULL) != HTTP_OK)
+ return -1;
+
+ return 0;
+}
+
+static int stateless_connect(const char *service_name)
+{
+ struct discovery *discover;
+ struct proxy_state p;
+
+ /*
+ * Run the info/refs request and see if the server supports protocol
+ * v2. If and only if the server supports v2 can we successfully
+ * establish a stateless connection, otherwise we need to tell the
+ * client to fallback to using other transport helper functions to
+ * complete their request.
+ */
+ discover = discover_refs(service_name, 0);
+ if (discover->version != protocol_v2) {
+ printf("fallback\n");
+ fflush(stdout);
+ return -1;
+ } else {
+ /* Stateless Connection established */
+ printf("\n");
+ fflush(stdout);
+ }
+
+ proxy_state_init(&p, service_name, discover->version);
+
+ /*
+ * Dump the capability listing that we got from the server earlier
+ * during the info/refs request.
+ */
+ write_or_die(p.out, discover->buf, discover->len);
+
+ /* Peek the next packet line. Until we see EOF keep sending POSTs */
+ while (packet_reader_peek(&p.reader) != PACKET_READ_EOF) {
+ if (proxy_request(&p)) {
+ /* We would have an err here */
+ break;
+ }
+ }
+
+ proxy_state_clear(&p);
+ return 0;
+}
+
int cmd_main(int argc, const char **argv)
{
struct strbuf buf = STRBUF_INIT;
@@ -1153,12 +1354,16 @@ int cmd_main(int argc, const char **argv)
fflush(stdout);
} else if (!strcmp(buf.buf, "capabilities")) {
+ printf("stateless-connect\n");
printf("fetch\n");
printf("option\n");
printf("push\n");
printf("check-connectivity\n");
printf("\n");
fflush(stdout);
+ } else if (skip_prefix(buf.buf, "stateless-connect ", &arg)) {
+ if (!stateless_connect(arg))
+ break;
} else {
error("remote-curl: unknown command '%s' from git",
buf.buf);
return 1;
diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
index e3a7c09d4a..124063c2c4 100755
--- a/t/t5702-protocol-v2.sh
+++ b/t/t5702-protocol-v2.sh
@@ -201,4 +201,49 @@ test_expect_success 'ref advertisment is filtered during
fetch using protocol v2
! grep "refs/tags/three" log
'
+# Test protocol v2 with 'http://' transport
+#
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success 'create repo to be served by http:// transport' '
+ git init "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" &&
+ git -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" config http.receivepack
true &&
+ test_commit -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" one
+'
+
+test_expect_success 'clone with http:// using protocol v2' '
+ test_when_finished "rm -f log" &&
+
+ GIT_TRACE_PACKET="$(pwd)/log" GIT_TRACE_CURL="$(pwd)/log" git -c
protocol.version=2 \
+ clone "$HTTPD_URL/smart/http_parent" http_child &&
+
+ git -C http_child log -1 --format=%s >actual &&
+ git -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" log -1 --format=%s
>expect &&
+ test_cmp expect actual &&
+
+ # Client requested to use protocol v2
+ grep "Git-Protocol: version=2" log &&
+ # Server responded using protocol v2
+ grep "git< version 2" log
+'
+
+test_expect_success 'fetch with http:// using protocol v2' '
+ test_when_finished "rm -f log" &&
+
+ test_commit -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" two &&
+
+ GIT_TRACE_PACKET="$(pwd)/log" git -C http_child -c protocol.version=2 \
+ fetch &&
+
+ git -C http_child log -1 --format=%s origin/master >actual &&
+ git -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" log -1 --format=%s
>expect &&
+ test_cmp expect actual &&
+
+ # Server responded using protocol v2
+ grep "git< version 2" log
+'
+
+stop_httpd
+
test_done
--
2.16.2.804.g6dcf76e118-goog
