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>
Brandon Williams committed
Oct 16, 2017 at 10:55 UTC
0c2f0d27038f2aa98082d8af35c53b2ec7e9ad92
2 files changed
+255
-5
connect.c
+32
-5
@@ -871,6 +871,7 @@ struct child_process *git_connect(int fd[2], const char *url,
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printf("Diag: path=%s\n", path ? path : "NULL");
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conn = NULL;
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} else if (protocol == PROTO_GIT) {
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+ struct strbuf request = STRBUF_INIT;
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/*
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* Set up virtual host information based on where we will
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* connect, unless the user has overridden us in
@@ -898,13 +899,25 @@ struct child_process *git_connect(int fd[2], const char *url,
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* Note: Do not add any other headers here! Doing so
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* will cause older git-daemon servers to crash.
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*/
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- packet_write_fmt(fd[1],
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- "%s %s%chost=%s%c",
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- prog, path, 0,
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- target_host, 0);
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+ strbuf_addf(&request,
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+ "%s %s%chost=%s%c",
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+ prog, path, 0,
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+ target_host, 0);
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+
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+ /* If using a new version put that stuff here after a second null byte */
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+ if (get_protocol_version_config() > 0) {
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+ strbuf_addch(&request, '\0');
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+ strbuf_addf(&request, "version=%d%c",
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+ get_protocol_version_config(), '\0');
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+ }
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+
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+ packet_write(fd[1], request.buf, request.len);
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+
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free(target_host);
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+ strbuf_release(&request);
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} else {
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struct strbuf cmd = STRBUF_INIT;
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+ const char *const *var;
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conn = xmalloc(sizeof(*conn));
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child_process_init(conn);
@@ -917,7 +930,9 @@ struct child_process *git_connect(int fd[2], const char *url,
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sq_quote_buf(&cmd, path);
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/* remove repo-local variables from the environment */
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- conn->env = local_repo_env;
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+ for (var = local_repo_env; *var; var++)
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+ argv_array_push(&conn->env_array, *var);
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+
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conn->use_shell = 1;
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conn->in = conn->out = -1;
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if (protocol == PROTO_SSH) {
@@ -971,6 +986,14 @@ struct child_process *git_connect(int fd[2], const char *url,
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}
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argv_array_push(&conn->args, ssh);
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+
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+ if (get_protocol_version_config() > 0) {
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+ argv_array_push(&conn->args, "-o");
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+ argv_array_push(&conn->args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
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+ argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
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+ get_protocol_version_config());
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+ }
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+
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if (flags & CONNECT_IPV4)
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argv_array_push(&conn->args, "-4");
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else if (flags & CONNECT_IPV6)
@@ -985,6 +1008,10 @@ struct child_process *git_connect(int fd[2], const char *url,
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argv_array_push(&conn->args, ssh_host);
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} else {
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transport_check_allowed("file");
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+ if (get_protocol_version_config() > 0) {
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+ argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
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+ get_protocol_version_config());
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+ }
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}
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argv_array_push(&conn->args, cmd.buf);
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t/t5700-protocol-v1.sh
new
+223
@@ -0,0 +1,223 @@
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+#!/bin/sh
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+
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+test_description='test git wire-protocol transition'
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+
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+TEST_NO_CREATE_REPO=1
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+
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+. ./test-lib.sh
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+
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+# Test protocol v1 with 'git://' transport
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+#
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+. "$TEST_DIRECTORY"/lib-git-daemon.sh
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+start_git_daemon --export-all --enable=receive-pack
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+daemon_parent=$GIT_DAEMON_DOCUMENT_ROOT_PATH/parent
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+
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+test_expect_success 'create repo to be served by git-daemon' '
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+ git init "$daemon_parent" &&
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+ test_commit -C "$daemon_parent" one
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+'
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+
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+test_expect_success 'clone with git:// using protocol v1' '
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+ GIT_TRACE_PACKET=1 git -c protocol.version=1 \
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+ clone "$GIT_DAEMON_URL/parent" daemon_child 2>log &&
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+
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+ git -C daemon_child log -1 --format=%s >actual &&
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+ git -C "$daemon_parent" log -1 --format=%s >expect &&
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+ test_cmp expect actual &&
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+
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+ # Client requested to use protocol v1
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+ grep "clone> .*\\\0\\\0version=1\\\0$" log &&
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+ # Server responded using protocol v1
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+ grep "clone< version 1" log
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+'
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+
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+test_expect_success 'fetch with git:// using protocol v1' '
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+ test_commit -C "$daemon_parent" two &&
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+
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+ GIT_TRACE_PACKET=1 git -C daemon_child -c protocol.version=1 \
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+ fetch 2>log &&
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+
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+ git -C daemon_child log -1 --format=%s origin/master >actual &&
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+ git -C "$daemon_parent" log -1 --format=%s >expect &&
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+ test_cmp expect actual &&
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+
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+ # Client requested to use protocol v1
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+ grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
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+ # Server responded using protocol v1
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+ grep "fetch< version 1" log
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+'
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+
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+test_expect_success 'pull with git:// using protocol v1' '
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+ GIT_TRACE_PACKET=1 git -C daemon_child -c protocol.version=1 \
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+ pull 2>log &&
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+
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+ git -C daemon_child log -1 --format=%s >actual &&
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+ git -C "$daemon_parent" log -1 --format=%s >expect &&
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+ test_cmp expect actual &&
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+
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+ # Client requested to use protocol v1
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+ grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
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+ # Server responded using protocol v1
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+ grep "fetch< version 1" log
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+'
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+
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+test_expect_success 'push with git:// using protocol v1' '
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+ test_commit -C daemon_child three &&
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+
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+ # Push to another branch, as the target repository has the
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+ # master branch checked out and we cannot push into it.
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+ GIT_TRACE_PACKET=1 git -C daemon_child -c protocol.version=1 \
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+ push origin HEAD:client_branch 2>log &&
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+
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+ git -C daemon_child log -1 --format=%s >actual &&
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+ git -C "$daemon_parent" log -1 --format=%s client_branch >expect &&
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+ test_cmp expect actual &&
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+
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+ # Client requested to use protocol v1
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+ grep "push> .*\\\0\\\0version=1\\\0$" log &&
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+ # Server responded using protocol v1
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+ grep "push< version 1" log
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+'
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+
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+stop_git_daemon
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+
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+# Test protocol v1 with 'file://' transport
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+#
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+test_expect_success 'create repo to be served by file:// transport' '
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+ git init file_parent &&
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+ test_commit -C file_parent one
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+'
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+
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+test_expect_success 'clone with file:// using protocol v1' '
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+ GIT_TRACE_PACKET=1 git -c protocol.version=1 \
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+ clone "file://$(pwd)/file_parent" file_child 2>log &&
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+
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+ git -C file_child log -1 --format=%s >actual &&
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+ git -C file_parent log -1 --format=%s >expect &&
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+ test_cmp expect actual &&
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+
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+ # Server responded using protocol v1
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+ grep "clone< version 1" log
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+'
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+
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+test_expect_success 'fetch with file:// using protocol v1' '
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+ test_commit -C file_parent two &&
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+
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+ GIT_TRACE_PACKET=1 git -C file_child -c protocol.version=1 \
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+ fetch 2>log &&
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+
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+ git -C file_child log -1 --format=%s origin/master >actual &&
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+ git -C file_parent log -1 --format=%s >expect &&
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+ test_cmp expect actual &&
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+
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+ # Server responded using protocol v1
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+ grep "fetch< version 1" log
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+'
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+
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+test_expect_success 'pull with file:// using protocol v1' '
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+ GIT_TRACE_PACKET=1 git -C file_child -c protocol.version=1 \
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+ pull 2>log &&
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+
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+ git -C file_child log -1 --format=%s >actual &&
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+ git -C file_parent log -1 --format=%s >expect &&
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+ test_cmp expect actual &&
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+
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+ # Server responded using protocol v1
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+ grep "fetch< version 1" log
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+'
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+
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+test_expect_success 'push with file:// using protocol v1' '
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+ test_commit -C file_child three &&
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+
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+ # Push to another branch, as the target repository has the
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+ # master branch checked out and we cannot push into it.
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+ GIT_TRACE_PACKET=1 git -C file_child -c protocol.version=1 \
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+ push origin HEAD:client_branch 2>log &&
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+
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+ git -C file_child log -1 --format=%s >actual &&
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+ git -C file_parent log -1 --format=%s client_branch >expect &&
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+ test_cmp expect actual &&
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+
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+ # Server responded using protocol v1
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+ grep "push< version 1" log
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+'
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+
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+# Test protocol v1 with 'ssh://' transport
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+#
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+test_expect_success 'setup ssh wrapper' '
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+ GIT_SSH="$GIT_BUILD_DIR/t/helper/test-fake-ssh" &&
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+ export GIT_SSH &&
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+ export TRASH_DIRECTORY &&
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+ >"$TRASH_DIRECTORY"/ssh-output
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+'
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+
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+expect_ssh () {
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+ test_when_finished '(cd "$TRASH_DIRECTORY" && rm -f ssh-expect && >ssh-output)' &&
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+ echo "ssh: -o SendEnv=GIT_PROTOCOL myhost $1 '$PWD/ssh_parent'" >"$TRASH_DIRECTORY/ssh-expect" &&
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+ (cd "$TRASH_DIRECTORY" && test_cmp ssh-expect ssh-output)
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+}
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+
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+test_expect_success 'create repo to be served by ssh:// transport' '
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+ git init ssh_parent &&
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+ test_commit -C ssh_parent one
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+'
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+
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+test_expect_success 'clone with ssh:// using protocol v1' '
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+ GIT_TRACE_PACKET=1 git -c protocol.version=1 \
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+ clone "ssh://myhost:$(pwd)/ssh_parent" ssh_child 2>log &&
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+ expect_ssh git-upload-pack &&
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+
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+ git -C ssh_child log -1 --format=%s >actual &&
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+ git -C ssh_parent log -1 --format=%s >expect &&
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+ test_cmp expect actual &&
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+
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+ # Server responded using protocol v1
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+ grep "clone< version 1" log
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+'
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+
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+test_expect_success 'fetch with ssh:// using protocol v1' '
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+ test_commit -C ssh_parent two &&
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+
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+ GIT_TRACE_PACKET=1 git -C ssh_child -c protocol.version=1 \
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+ fetch 2>log &&
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+ expect_ssh git-upload-pack &&
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+
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+ git -C ssh_child log -1 --format=%s origin/master >actual &&
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+ git -C ssh_parent log -1 --format=%s >expect &&
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+ test_cmp expect actual &&
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+
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+ # Server responded using protocol v1
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+ grep "fetch< version 1" log
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+'
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+
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+test_expect_success 'pull with ssh:// using protocol v1' '
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+ GIT_TRACE_PACKET=1 git -C ssh_child -c protocol.version=1 \
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+ pull 2>log &&
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+ expect_ssh git-upload-pack &&
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+
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+ git -C ssh_child log -1 --format=%s >actual &&
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+ git -C ssh_parent log -1 --format=%s >expect &&
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+ test_cmp expect actual &&
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+
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+ # Server responded using protocol v1
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+ grep "fetch< version 1" log
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+'
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+
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+test_expect_success 'push with ssh:// using protocol v1' '
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+ test_commit -C ssh_child three &&
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+
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+ # Push to another branch, as the target repository has the
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+ # master branch checked out and we cannot push into it.
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+ GIT_TRACE_PACKET=1 git -C ssh_child -c protocol.version=1 \
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+ push origin HEAD:client_branch 2>log &&
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+ expect_ssh git-receive-pack &&
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+
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+ git -C ssh_child log -1 --format=%s >actual &&
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+ git -C ssh_parent log -1 --format=%s client_branch >expect &&
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+ test_cmp expect actual &&
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+
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+ # Server responded using protocol v1
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+ grep "push< version 1" log
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+'
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+
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+test_done