OpenSSH has the nice feature that it sets the IP TOS value of its
connection depending on usage. When used in interactive mode, it
is set to Minimize-Delay, and other wise to Maximize-Throughput. Its
usage by Git is best served by Maximize-Throughput, for obvious
reasons.
However, it seems to use a DWIM heuristic for detecting interactive
mode. The current implementation enters interactive mode if either
a PTY is allocated or X11 forwarding is enabled, and even though Git
SSH:ing does not allocate a PTY, X11 forwarding is often turned on
by default.
This patch allows the Git config file to specify the SSH command to
use and its parameters in a rather flexible manner. It should also be
enough to configure Git to use other SSH implementations than OpenSSH.
Signed-off-by: Fredrik Tolf <fredrik@xxxxxxxxxxxxx>
---
I'm following my previous SSH patch up with this one, which should at
least solve the problems discussed, and probably some more. If anything,
it might be considered a bit overkill for the problem at hand.
I assume it might have to be documented as well, if people approve of it.
connect.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 117 insertions(+), 13 deletions(-)
diff --git a/connect.c b/connect.c
index 574f42f..46379fa 100644
--- a/connect.c
+++ b/connect.c
@@ -474,6 +474,114 @@ char *get_port(char *host)
return NULL;
}
+static char *git_ssh_command;
+static struct {
+ char *name;
+ char *exp;
+} ssh_templates[] = {
+ {"openssh", "ssh -xT %P-p %p %h"},
+ {"plink", "plink %P-P %p %h"},
+ {NULL, NULL}
+};
+
+static int git_ssh_command_options(const char *var, const char *value, void *cb)
+{
+ int i;
+
+ if(!strcmp(var, "core.sshcommand")) {
+ if(git_ssh_command)
+ return 0;
+ if(!value)
+ return config_error_nonbool(var);
+ if(strchr(value, ' ')) {
+ git_ssh_command = xstrdup(value);
+ } else {
+ for(i = 0; ssh_templates[i].name; i++) {
+ if(!strcmp(ssh_templates[i].name, value)) {
+ git_ssh_command = xstrdup(ssh_templates[i].exp);
+ break;
+ }
+ }
+ if(git_ssh_command == NULL)
+ git_ssh_command = xstrdup(value);
+ }
+ }
+
+ return git_default_config(var, value, cb);
+}
+
+static char *ssh_arg_subst(char *arg, const char *host, const char *port)
+{
+ if(!strncmp(arg, "%P", 2)) {
+ if(!port)
+ return NULL;
+ return xstrdup(arg + 2);
+ } else if(!strcmp(arg, "%p")) {
+ if(!port)
+ return NULL;
+ return xstrdup(port);
+ } else if(!strcmp(arg, "%h")) {
+ return xstrdup(host);
+ }
+ return arg;
+}
+
+static const char **setup_ssh_command(const char *host, const char *port, int extra_args)
+{
+ char **argv;
+ char *tok, *buf;
+ int i, sz;
+
+ if((buf = getenv("GIT_SSH")) != NULL) {
+ if(port) {
+ argv = xcalloc(5 + extra_args, sizeof(*argv));
+ argv[0] = xstrdup(buf);
+ argv[1] = xstrdup("-p");
+ argv[2] = xstrdup(port);
+ argv[3] = xstrdup(host);
+ } else {
+ argv = xcalloc(3 + extra_args, sizeof(*argv));
+ argv[0] = xstrdup(buf);
+ argv[1] = xstrdup(host);
+ }
+ return (const char **)argv;
+ }
+
+ git_config(git_ssh_command_options, NULL);
+ if(git_ssh_command == NULL)
+ buf = xstrdup(ssh_templates[0].exp);
+ else
+ buf = xstrdup(git_ssh_command);
+
+ argv = xmalloc((sz = 5) * sizeof(*argv));
+ for(i = 0, tok = strtok(buf, " "); tok != NULL; tok = strtok(NULL, " ")) {
+ argv[i++] = xstrdup(tok);
+ if(sz - i < 1)
+ argv = xrealloc(argv, (sz += 5) * sizeof(*argv));
+ }
+ argv[i] = NULL;
+ argv = xrealloc(argv, ((sz = i) + extra_args + 1) * sizeof(*argv));
+ free(buf);
+
+ for(i = 0; i < sz;) {
+ buf = ssh_arg_subst(argv[i], host, port);
+ if(buf == argv[i]) {
+ i++;
+ continue;
+ } else if(buf == NULL) {
+ free(argv[i]);
+ memmove(argv + i, argv + i + 1, sizeof(*argv) * (sz-- - i));
+ continue;
+ } else {
+ free(argv[i]);
+ argv[i] = buf;
+ i++;
+ }
+ }
+
+ return (const char **)argv;
+}
+
static struct child_process no_fork;
/*
@@ -596,19 +704,12 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
die("command line too long");
conn->in = conn->out = -1;
- conn->argv = arg = xcalloc(6, sizeof(*arg));
if (protocol == PROTO_SSH) {
- const char *ssh = getenv("GIT_SSH");
- if (!ssh) ssh = "ssh";
-
- *arg++ = ssh;
- if (port) {
- *arg++ = "-p";
- *arg++ = port;
- }
- *arg++ = host;
+ conn->argv = setup_ssh_command(host, port, 1);
+ for(arg = conn->argv; *arg; arg++);
}
else {
+ conn->argv = arg = xcalloc(6, sizeof(*arg));
/* remove these from the environment */
const char *env[] = {
ALTERNATE_DB_ENVIRONMENT,
@@ -620,10 +721,10 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
NULL
};
conn->env = env;
- *arg++ = "sh";
- *arg++ = "-c";
+ *arg++ = xstrdup("sh");
+ *arg++ = xstrdup("-c");
}
- *arg++ = cmd.buf;
+ *arg++ = xstrdup(cmd.buf);
*arg = NULL;
if (start_command(conn))
@@ -640,11 +741,14 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
int finish_connect(struct child_process *conn)
{
+ const char **argp;
int code;
if (!conn || conn == &no_fork)
return 0;
code = finish_command(conn);
+ for(argp = conn->argv; *argp; argp++)
+ free((void *)*argp);
free(conn->argv);
free(conn);
return code;
--
1.5.6.2
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