connect: tell server that the client understands v1

Teach the connection logic to tell a serve that it understands protocol
v1.  This is done in 2 different ways for the builtin transports, both
of which ultimately set 'GIT_PROTOCOL' to 'version=1' on the server.

1. git://
A normal request to git-daemon is structured as
"command path/to/repo\0host=..\0" and due to a bug introduced in
49ba83fb6 (Add virtualization support to git-daemon, 2006-09-19) we
aren't able to place any extra arguments (separated by NULs) besides
the host otherwise the parsing of those arguments would enter an
infinite loop.  This bug was fixed in 73bb33a94 (daemon: Strictly
parse the "extra arg" part of the command, 2009-06-04) but a check
was put in place to disallow extra arguments so that new clients
wouldn't trigger this bug in older servers.

In order to get around this limitation git-daemon was taught to
recognize additional request arguments hidden behind a second
NUL byte.  Requests can then be structured like:
"command path/to/repo\0host=..\0\0version=1\0key=value\0".
git-daemon can then parse out the extra arguments and set
'GIT_PROTOCOL' accordingly.

By placing these extra arguments behind a second NUL byte we can
skirt around both the infinite loop bug in 49ba83fb6 (Add
virtualization support to git-daemon, 2006-09-19) as well as the
explicit disallowing of extra arguments introduced in 73bb33a94
(daemon: Strictly parse the "extra arg" part of the command,
2009-06-04) because both of these versions of git-daemon check for a
single NUL byte after the host argument before terminating the
argument parsing.

2. ssh://, file://
Set 'GIT_PROTOCOL' environment variable with the desired protocol
version.  With the file:// transport, 'GIT_PROTOCOL' can be set
explicitly in the locally running git-upload-pack or git-receive-pack
processes.  With the ssh:// transport and OpenSSH compliant ssh
programs, 'GIT_PROTOCOL' can be sent across ssh by using '-o
SendEnv=GIT_PROTOCOL' and having the server whitelist this
environment variable.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/connect.c b/connect.c
index a5e708a618cd71b230437b5c172d8c78bfcfd3b1..b8695a2fa28b5fd9eb9dc4b3e0291b481c57bd6a 100644 (file)
--- a/connect.c
+++ b/connect.c
@@ -871,6 +871,7 @@ struct child_process *git_connect(int fd[2], const char *url,
                printf("Diag: path=%s\n", path ? path : "NULL");
                conn = NULL;
        } else if (protocol == PROTO_GIT) {
                printf("Diag: path=%s\n", path ? path : "NULL");
                conn = NULL;
        } else if (protocol == PROTO_GIT) {

+               struct strbuf request = STRBUF_INIT;

                /*
                 * Set up virtual host information based on where we will
                 * connect, unless the user has overridden us in
                /*
                 * Set up virtual host information based on where we will
                 * connect, unless the user has overridden us in


@@ -898,13 +899,25 @@ struct child_process *git_connect(int fd[2], const char *url,
                 * Note: Do not add any other headers here!  Doing so
                 * will cause older git-daemon servers to crash.
                 */
                 * Note: Do not add any other headers here!  Doing so
                 * will cause older git-daemon servers to crash.
                 */

-               packet_write_fmt(fd[1],
-                            "%s %s%chost=%s%c",
-                            prog, path, 0,
-                            target_host, 0);
+               strbuf_addf(&request,
+                           "%s %s%chost=%s%c",
+                           prog, path, 0,
+                           target_host, 0);
+
+               /* If using a new version put that stuff here after a second null byte */
+               if (get_protocol_version_config() > 0) {
+                       strbuf_addch(&request, '\0');
+                       strbuf_addf(&request, "version=%d%c",
+                                   get_protocol_version_config(), '\0');
+               }
+
+               packet_write(fd[1], request.buf, request.len);
+

                free(target_host);
                free(target_host);

+               strbuf_release(&request);

        } else {
                struct strbuf cmd = STRBUF_INIT;
        } else {
                struct strbuf cmd = STRBUF_INIT;

+               const char *const *var;

 
                conn = xmalloc(sizeof(*conn));
                child_process_init(conn);
 
                conn = xmalloc(sizeof(*conn));
                child_process_init(conn);


@@ -917,7 +930,9 @@ struct child_process *git_connect(int fd[2], const char *url,
                sq_quote_buf(&cmd, path);
 
                /* remove repo-local variables from the environment */
                sq_quote_buf(&cmd, path);
 
                /* remove repo-local variables from the environment */

-               conn->env = local_repo_env;
+               for (var = local_repo_env; *var; var++)
+                       argv_array_push(&conn->env_array, *var);
+

                conn->use_shell = 1;
                conn->in = conn->out = -1;
                if (protocol == PROTO_SSH) {
                conn->use_shell = 1;
                conn->in = conn->out = -1;
                if (protocol == PROTO_SSH) {


@@ -971,6 +986,14 @@ struct child_process *git_connect(int fd[2], const char *url,
                        }
 
                        argv_array_push(&conn->args, ssh);
                        }
 
                        argv_array_push(&conn->args, ssh);

+
+                       if (get_protocol_version_config() > 0) {
+                               argv_array_push(&conn->args, "-o");
+                               argv_array_push(&conn->args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
+                               argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
+                                                get_protocol_version_config());
+                       }
+

                        if (flags & CONNECT_IPV4)
                                argv_array_push(&conn->args, "-4");
                        else if (flags & CONNECT_IPV6)
                        if (flags & CONNECT_IPV4)
                                argv_array_push(&conn->args, "-4");
                        else if (flags & CONNECT_IPV6)


@@ -985,6 +1008,10 @@ struct child_process *git_connect(int fd[2], const char *url,
                        argv_array_push(&conn->args, ssh_host);
                } else {
                        transport_check_allowed("file");
                        argv_array_push(&conn->args, ssh_host);
                } else {
                        transport_check_allowed("file");

+                       if (get_protocol_version_config() > 0) {
+                               argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
+                                                get_protocol_version_config());
+                       }

                }
                argv_array_push(&conn->args, cmd.buf);
 
                }
                argv_array_push(&conn->args, cmd.buf);
 

diff --git a/t/t5700-protocol-v1.sh b/t/t5700-protocol-v1.sh
new file mode 100755 (executable)
index 0000000..6551932
--- /dev/null
+++ b/t/t5700-protocol-v1.sh
@@ -0,0 +1,223 @@
+#!/bin/sh
+
+test_description='test git wire-protocol transition'
+
+TEST_NO_CREATE_REPO=1
+
+. ./test-lib.sh
+
+# Test protocol v1 with 'git://' transport
+#
+. "$TEST_DIRECTORY"/lib-git-daemon.sh
+start_git_daemon --export-all --enable=receive-pack
+daemon_parent=$GIT_DAEMON_DOCUMENT_ROOT_PATH/parent
+
+test_expect_success 'create repo to be served by git-daemon' '
+       git init "$daemon_parent" &&
+       test_commit -C "$daemon_parent" one
+'
+
+test_expect_success 'clone with git:// using protocol v1' '
+       GIT_TRACE_PACKET=1 git -c protocol.version=1 \
+               clone "$GIT_DAEMON_URL/parent" daemon_child 2>log &&
+
+       git -C daemon_child log -1 --format=%s >actual &&
+       git -C "$daemon_parent" log -1 --format=%s >expect &&
+       test_cmp expect actual &&
+
+       # Client requested to use protocol v1
+       grep "clone> .*\\\0\\\0version=1\\\0$" log &&
+       # Server responded using protocol v1
+       grep "clone< version 1" log
+'
+
+test_expect_success 'fetch with git:// using protocol v1' '
+       test_commit -C "$daemon_parent" two &&
+
+       GIT_TRACE_PACKET=1 git -C daemon_child -c protocol.version=1 \
+               fetch 2>log &&
+
+       git -C daemon_child log -1 --format=%s origin/master >actual &&
+       git -C "$daemon_parent" log -1 --format=%s >expect &&
+       test_cmp expect actual &&
+
+       # Client requested to use protocol v1
+       grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
+       # Server responded using protocol v1
+       grep "fetch< version 1" log
+'
+
+test_expect_success 'pull with git:// using protocol v1' '
+       GIT_TRACE_PACKET=1 git -C daemon_child -c protocol.version=1 \
+               pull 2>log &&
+
+       git -C daemon_child log -1 --format=%s >actual &&
+       git -C "$daemon_parent" log -1 --format=%s >expect &&
+       test_cmp expect actual &&
+
+       # Client requested to use protocol v1
+       grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
+       # Server responded using protocol v1
+       grep "fetch< version 1" log
+'
+
+test_expect_success 'push with git:// using protocol v1' '
+       test_commit -C daemon_child three &&
+
+       # Push to another branch, as the target repository has the
+       # master branch checked out and we cannot push into it.
+       GIT_TRACE_PACKET=1 git -C daemon_child -c protocol.version=1 \
+               push origin HEAD:client_branch 2>log &&
+
+       git -C daemon_child log -1 --format=%s >actual &&
+       git -C "$daemon_parent" log -1 --format=%s client_branch >expect &&
+       test_cmp expect actual &&
+
+       # Client requested to use protocol v1
+       grep "push> .*\\\0\\\0version=1\\\0$" log &&
+       # Server responded using protocol v1
+       grep "push< version 1" log
+'
+
+stop_git_daemon
+
+# Test protocol v1 with 'file://' transport
+#
+test_expect_success 'create repo to be served by file:// transport' '
+       git init file_parent &&
+       test_commit -C file_parent one
+'
+
+test_expect_success 'clone with file:// using protocol v1' '
+       GIT_TRACE_PACKET=1 git -c protocol.version=1 \
+               clone "file://$(pwd)/file_parent" file_child 2>log &&
+
+       git -C file_child log -1 --format=%s >actual &&
+       git -C file_parent log -1 --format=%s >expect &&
+       test_cmp expect actual &&
+
+       # Server responded using protocol v1
+       grep "clone< version 1" log
+'
+
+test_expect_success 'fetch with file:// using protocol v1' '
+       test_commit -C file_parent two &&
+
+       GIT_TRACE_PACKET=1 git -C file_child -c protocol.version=1 \
+               fetch 2>log &&
+
+       git -C file_child log -1 --format=%s origin/master >actual &&
+       git -C file_parent log -1 --format=%s >expect &&
+       test_cmp expect actual &&
+
+       # Server responded using protocol v1
+       grep "fetch< version 1" log
+'
+
+test_expect_success 'pull with file:// using protocol v1' '
+       GIT_TRACE_PACKET=1 git -C file_child -c protocol.version=1 \
+               pull 2>log &&
+
+       git -C file_child log -1 --format=%s >actual &&
+       git -C file_parent log -1 --format=%s >expect &&
+       test_cmp expect actual &&
+
+       # Server responded using protocol v1
+       grep "fetch< version 1" log
+'
+
+test_expect_success 'push with file:// using protocol v1' '
+       test_commit -C file_child three &&
+
+       # Push to another branch, as the target repository has the
+       # master branch checked out and we cannot push into it.
+       GIT_TRACE_PACKET=1 git -C file_child -c protocol.version=1 \
+               push origin HEAD:client_branch 2>log &&
+
+       git -C file_child log -1 --format=%s >actual &&
+       git -C file_parent log -1 --format=%s client_branch >expect &&
+       test_cmp expect actual &&
+
+       # Server responded using protocol v1
+       grep "push< version 1" log
+'
+
+# Test protocol v1 with 'ssh://' transport
+#
+test_expect_success 'setup ssh wrapper' '
+       GIT_SSH="$GIT_BUILD_DIR/t/helper/test-fake-ssh" &&
+       export GIT_SSH &&
+       export TRASH_DIRECTORY &&
+       >"$TRASH_DIRECTORY"/ssh-output
+'
+
+expect_ssh () {
+       test_when_finished '(cd "$TRASH_DIRECTORY" && rm -f ssh-expect && >ssh-output)' &&
+       echo "ssh: -o SendEnv=GIT_PROTOCOL myhost $1 '$PWD/ssh_parent'" >"$TRASH_DIRECTORY/ssh-expect" &&
+       (cd "$TRASH_DIRECTORY" && test_cmp ssh-expect ssh-output)
+}
+
+test_expect_success 'create repo to be served by ssh:// transport' '
+       git init ssh_parent &&
+       test_commit -C ssh_parent one
+'
+
+test_expect_success 'clone with ssh:// using protocol v1' '
+       GIT_TRACE_PACKET=1 git -c protocol.version=1 \
+               clone "ssh://myhost:$(pwd)/ssh_parent" ssh_child 2>log &&
+       expect_ssh git-upload-pack &&
+
+       git -C ssh_child log -1 --format=%s >actual &&
+       git -C ssh_parent log -1 --format=%s >expect &&
+       test_cmp expect actual &&
+
+       # Server responded using protocol v1
+       grep "clone< version 1" log
+'
+
+test_expect_success 'fetch with ssh:// using protocol v1' '
+       test_commit -C ssh_parent two &&
+
+       GIT_TRACE_PACKET=1 git -C ssh_child -c protocol.version=1 \
+               fetch 2>log &&
+       expect_ssh git-upload-pack &&
+
+       git -C ssh_child log -1 --format=%s origin/master >actual &&
+       git -C ssh_parent log -1 --format=%s >expect &&
+       test_cmp expect actual &&
+
+       # Server responded using protocol v1
+       grep "fetch< version 1" log
+'
+
+test_expect_success 'pull with ssh:// using protocol v1' '
+       GIT_TRACE_PACKET=1 git -C ssh_child -c protocol.version=1 \
+               pull 2>log &&
+       expect_ssh git-upload-pack &&
+
+       git -C ssh_child log -1 --format=%s >actual &&
+       git -C ssh_parent log -1 --format=%s >expect &&
+       test_cmp expect actual &&
+
+       # Server responded using protocol v1
+       grep "fetch< version 1" log
+'
+
+test_expect_success 'push with ssh:// using protocol v1' '
+       test_commit -C ssh_child three &&
+
+       # Push to another branch, as the target repository has the
+       # master branch checked out and we cannot push into it.
+       GIT_TRACE_PACKET=1 git -C ssh_child -c protocol.version=1 \
+               push origin HEAD:client_branch 2>log &&
+       expect_ssh git-receive-pack &&
+
+       git -C ssh_child log -1 --format=%s >actual &&
+       git -C ssh_parent log -1 --format=%s client_branch >expect &&
+       test_cmp expect actual &&
+
+       # Server responded using protocol v1
+       grep "push< version 1" log
+'
+
+test_done