ssh: introduce a 'simple' ssh variant
When using the 'ssh' transport, the '-o' option is used to specify an environment variable which should be set on the remote end. This allows git to send additional information when contacting the server, requesting the use of a different protocol version via the 'GIT_PROTOCOL' environment variable like so: "-o SendEnv=GIT_PROTOCOL". Unfortunately not all ssh variants support the sending of environment variables to the remote end. To account for this, only use the '-o' option for ssh variants which are OpenSSH compliant. This is done by checking that the basename of the ssh command is 'ssh' or the ssh variant is overridden to be 'ssh' (via the ssh.variant config). Other options like '-p' and '-P', which are used to specify a specific port to use, or '-4' and '-6', which are used to indicate that IPV4 or IPV6 addresses should be used, may also not be supported by all ssh variants. Currently if an ssh command's basename wasn't 'plink' or 'tortoiseplink' git assumes that the command is an OpenSSH variant. Since user configured ssh commands may not be OpenSSH compliant, tighten this constraint and assume a variant of 'simple' if the basename of the command doesn't match the variants known to git. The new ssh variant 'simple' will only have the host and command to execute ([username@]host command) passed as parameters to the ssh command. Update the Documentation to better reflect the command-line options sent to ssh commands based on their variant. Reported-by: Jeffrey Yasskin <jyasskin@google.com> 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
94b8ae5aca41538cf78918663f8b8294f6dcaa21
5 files changed
+111
-61
Documentation/config.txt
+23
-4
@@ -2084,12 +2084,31 @@ ssh.variant::
2084
Depending on the value of the environment variables `GIT_SSH` or
2085
`GIT_SSH_COMMAND`, or the config setting `core.sshCommand`, Git
2086
auto-detects whether to adjust its command-line parameters for use
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- with plink or tortoiseplink, as opposed to the default (OpenSSH).
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+ with ssh (OpenSSH), plink or tortoiseplink, as opposed to the default
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+ (simple).
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+
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The config variable `ssh.variant` can be set to override this auto-detection;
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-valid values are `ssh`, `plink`, `putty` or `tortoiseplink`. Any other value
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-will be treated as normal ssh. This setting can be overridden via the
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-environment variable `GIT_SSH_VARIANT`.
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+valid values are `ssh`, `simple`, `plink`, `putty` or `tortoiseplink`. Any
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+other value will be treated as normal ssh. This setting can be overridden via
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+the environment variable `GIT_SSH_VARIANT`.
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++
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+The current command-line parameters used for each variant are as
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+follows:
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++
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+--
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+
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+* `ssh` - [-p port] [-4] [-6] [-o option] [username@]host command
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+
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+* `simple` - [username@]host command
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+
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+* `plink` or `putty` - [-P port] [-4] [-6] [username@]host command
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+
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+* `tortoiseplink` - [-P port] [-4] [-6] -batch [username@]host command
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+
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+--
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++
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+Except for the `simple` variant, command-line parameters are likely to
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+change as git gains new features.
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2113
i18n.commitEncoding::
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Character encoding the commit messages are stored in; Git itself
Documentation/git.txt
+4
-5
@@ -518,11 +518,10 @@ other
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If either of these environment variables is set then 'git fetch'
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and 'git push' will use the specified command instead of 'ssh'
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when they need to connect to a remote system.
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- The command will be given exactly two or four arguments: the
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- 'username@host' (or just 'host') from the URL and the shell
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- command to execute on that remote system, optionally preceded by
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- `-p` (literally) and the 'port' from the URL when it specifies
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- something other than the default SSH port.
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+ The command-line parameters passed to the configured command are
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+ determined by the ssh variant. See `ssh.variant` option in
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+ linkgit:git-config[1] for details.
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+
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+
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`$GIT_SSH_COMMAND` takes precedence over `$GIT_SSH`, and is interpreted
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by the shell, which allows additional arguments to be included.
connect.c
+61
-47
@@ -776,37 +776,44 @@ static const char *get_ssh_command(void)
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return NULL;
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}
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-static int override_ssh_variant(int *port_option, int *needs_batch)
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+enum ssh_variant {
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+ VARIANT_SIMPLE,
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+ VARIANT_SSH,
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+ VARIANT_PLINK,
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+ VARIANT_PUTTY,
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+ VARIANT_TORTOISEPLINK,
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+};
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+
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+static int override_ssh_variant(enum ssh_variant *ssh_variant)
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{
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- char *variant;
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+ const char *variant = getenv("GIT_SSH_VARIANT");
790
783
- variant = xstrdup_or_null(getenv("GIT_SSH_VARIANT"));
784
- if (!variant &&
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- git_config_get_string("ssh.variant", &variant))
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+ if (!variant && git_config_get_string_const("ssh.variant", &variant))
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return 0;
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788
- if (!strcmp(variant, "plink") || !strcmp(variant, "putty")) {
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- *port_option = 'P';
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- *needs_batch = 0;
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- } else if (!strcmp(variant, "tortoiseplink")) {
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- *port_option = 'P';
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- *needs_batch = 1;
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- } else {
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- *port_option = 'p';
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- *needs_batch = 0;
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- }
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- free(variant);
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+ if (!strcmp(variant, "plink"))
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+ *ssh_variant = VARIANT_PLINK;
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+ else if (!strcmp(variant, "putty"))
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+ *ssh_variant = VARIANT_PUTTY;
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+ else if (!strcmp(variant, "tortoiseplink"))
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+ *ssh_variant = VARIANT_TORTOISEPLINK;
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+ else if (!strcmp(variant, "simple"))
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+ *ssh_variant = VARIANT_SIMPLE;
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+ else
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+ *ssh_variant = VARIANT_SSH;
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+
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return 1;
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}
807
802
-static void handle_ssh_variant(const char *ssh_command, int is_cmdline,
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- int *port_option, int *needs_batch)
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+static enum ssh_variant determine_ssh_variant(const char *ssh_command,
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+ int is_cmdline)
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{
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+ enum ssh_variant ssh_variant = VARIANT_SIMPLE;
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const char *variant;
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char *p = NULL;
814
808
- if (override_ssh_variant(port_option, needs_batch))
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- return;
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+ if (override_ssh_variant(&ssh_variant))
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+ return ssh_variant;
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if (!is_cmdline) {
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p = xstrdup(ssh_command);
@@ -825,19 +832,22 @@ static void handle_ssh_variant(const char *ssh_command, int is_cmdline,
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free(ssh_argv);
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} else {
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free(p);
828
- return;
835
+ return ssh_variant;
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}
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}
838
832
- if (!strcasecmp(variant, "plink") ||
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- !strcasecmp(variant, "plink.exe"))
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- *port_option = 'P';
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+ if (!strcasecmp(variant, "ssh") ||
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+ !strcasecmp(variant, "ssh.exe"))
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+ ssh_variant = VARIANT_SSH;
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+ else if (!strcasecmp(variant, "plink") ||
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+ !strcasecmp(variant, "plink.exe"))
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+ ssh_variant = VARIANT_PLINK;
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else if (!strcasecmp(variant, "tortoiseplink") ||
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- !strcasecmp(variant, "tortoiseplink.exe")) {
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- *port_option = 'P';
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- *needs_batch = 1;
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- }
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+ !strcasecmp(variant, "tortoiseplink.exe"))
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+ ssh_variant = VARIANT_TORTOISEPLINK;
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+
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free(p);
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+ return ssh_variant;
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}
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/*
@@ -937,8 +947,7 @@ struct child_process *git_connect(int fd[2], const char *url,
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conn->in = conn->out = -1;
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if (protocol == PROTO_SSH) {
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const char *ssh;
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- int needs_batch = 0;
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- int port_option = 'p';
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+ enum ssh_variant variant;
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char *ssh_host = hostandport;
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const char *port = NULL;
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transport_check_allowed("ssh");
@@ -965,10 +974,9 @@ struct child_process *git_connect(int fd[2], const char *url,
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die("strange hostname '%s' blocked", ssh_host);
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ssh = get_ssh_command();
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- if (ssh)
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- handle_ssh_variant(ssh, 1, &port_option,
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- &needs_batch);
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- else {
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+ if (ssh) {
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+ variant = determine_ssh_variant(ssh, 1);
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+ } else {
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/*
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* GIT_SSH is the no-shell version of
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* GIT_SSH_COMMAND (and must remain so for
@@ -979,32 +987,38 @@ struct child_process *git_connect(int fd[2], const char *url,
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ssh = getenv("GIT_SSH");
988
if (!ssh)
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ssh = "ssh";
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- else
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- handle_ssh_variant(ssh, 0,
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- &port_option,
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- &needs_batch);
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+ variant = determine_ssh_variant(ssh, 0);
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}
992
993
argv_array_push(&conn->args, ssh);
994
990
- if (get_protocol_version_config() > 0) {
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+ if (variant == VARIANT_SSH &&
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+ 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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}
1002
997
- if (flags & CONNECT_IPV4)
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- argv_array_push(&conn->args, "-4");
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- else if (flags & CONNECT_IPV6)
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- argv_array_push(&conn->args, "-6");
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- if (needs_batch)
1003
+ if (variant != VARIANT_SIMPLE) {
1004
+ if (flags & CONNECT_IPV4)
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+ argv_array_push(&conn->args, "-4");
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+ else if (flags & CONNECT_IPV6)
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+ argv_array_push(&conn->args, "-6");
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+ }
1009
+
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+ if (variant == VARIANT_TORTOISEPLINK)
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argv_array_push(&conn->args, "-batch");
1003
- if (port) {
1004
- argv_array_pushf(&conn->args,
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- "-%c", port_option);
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+
1013
+ if (port && variant != VARIANT_SIMPLE) {
1014
+ if (variant == VARIANT_SSH)
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+ argv_array_push(&conn->args, "-p");
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+ else
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+ argv_array_push(&conn->args, "-P");
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+
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argv_array_push(&conn->args, port);
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}
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+
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argv_array_push(&conn->args, ssh_host);
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} else {
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transport_check_allowed("file");
t/t5601-clone.sh
+21
-5
@@ -309,8 +309,8 @@ test_expect_success 'clone checking out a tag' '
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setup_ssh_wrapper () {
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test_expect_success 'setup ssh wrapper' '
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cp "$GIT_BUILD_DIR/t/helper/test-fake-ssh$X" \
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- "$TRASH_DIRECTORY/ssh-wrapper$X" &&
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- GIT_SSH="$TRASH_DIRECTORY/ssh-wrapper$X" &&
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+ "$TRASH_DIRECTORY/ssh$X" &&
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+ GIT_SSH="$TRASH_DIRECTORY/ssh$X" &&
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export GIT_SSH &&
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export TRASH_DIRECTORY &&
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>"$TRASH_DIRECTORY"/ssh-output
@@ -318,7 +318,7 @@ setup_ssh_wrapper () {
318
}
319
320
copy_ssh_wrapper_as () {
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- cp "$TRASH_DIRECTORY/ssh-wrapper$X" "${1%$X}$X" &&
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+ cp "$TRASH_DIRECTORY/ssh$X" "${1%$X}$X" &&
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GIT_SSH="${1%$X}$X" &&
323
export GIT_SSH
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}
@@ -362,10 +362,26 @@ test_expect_success 'bracketed hostnames are still ssh' '
362
expect_ssh "-p 123" myhost src
363
'
364
365
-test_expect_success 'uplink is not treated as putty' '
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+test_expect_success 'OpenSSH variant passes -4' '
366
+ git clone -4 "[myhost:123]:src" ssh-ipv4-clone &&
367
+ expect_ssh "-4 -p 123" myhost src
368
+'
369
+
370
+test_expect_success 'variant can be overriden' '
371
+ git -c ssh.variant=simple clone -4 "[myhost:123]:src" ssh-simple-clone &&
372
+ expect_ssh myhost src
373
+'
374
+
375
+test_expect_success 'simple is treated as simple' '
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+ copy_ssh_wrapper_as "$TRASH_DIRECTORY/simple" &&
377
+ git clone -4 "[myhost:123]:src" ssh-bracket-clone-simple &&
378
+ expect_ssh myhost src
379
+'
380
+
381
+test_expect_success 'uplink is treated as simple' '
382
copy_ssh_wrapper_as "$TRASH_DIRECTORY/uplink" &&
383
git clone "[myhost:123]:src" ssh-bracket-clone-uplink &&
368
- expect_ssh "-p 123" myhost src
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+ expect_ssh myhost src
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'
386
387
test_expect_success 'plink is treated specially (as putty)' '
t/t5700-protocol-v1.sh
+2
@@ -147,6 +147,8 @@ test_expect_success 'push with file:// using protocol v1' '
147
test_expect_success 'setup ssh wrapper' '
148
GIT_SSH="$GIT_BUILD_DIR/t/helper/test-fake-ssh" &&
149
export GIT_SSH &&
150
+ GIT_SSH_VARIANT=ssh &&
151
+ export GIT_SSH_VARIANT &&
152
export TRASH_DIRECTORY &&
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>"$TRASH_DIRECTORY"/ssh-output
154
'