proxy-command support for git://

Here is an updated patch that first looks for GIT_PROXY_COMMAND
in the environment and then git.proxycommand in the repository's
configuration file.  I have left the calling convention the same
argv[1] is the host and argv[2] is the port.

I've taken the hostname parsing verbatim from git_tcp_connect(),
so it should now support an explicit port number and whatever
that business with the square brackets is.  (Should I move this
to a helper function?)

Regarding internal vs. external hosts, the proxy command can
simply run netcat locally to internal hosts, so perhaps that is
sufficient.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/connect.c b/connect.c
index 73187a1..be88ef0 100644 (file)
--- a/connect.c
+++ b/connect.c
@@ -448,6 +448,73 @@ static int git_tcp_connect(int fd[2], const char *prog, char *host, char *path)
 
 #endif /* NO_IPV6 */
 
+static char *git_proxy_command = NULL;
+
+static int git_proxy_command_options(const char *var, const char *value)
+{
+       if (git_proxy_command == NULL) {
+               if (!strcmp(var, "git.proxycommand")) {
+                       git_proxy_command = xmalloc(strlen(value) + 1);
+                       strcpy(git_proxy_command, value);
+                       return 0;
+               }
+       }
+
+       return git_default_config(var, value);
+}
+
+static int git_use_proxy(void)
+{
+       git_proxy_command = getenv("GIT_PROXY_COMMAND");
+       git_config(git_proxy_command_options);
+       return git_proxy_command != NULL;
+}
+
+static int git_proxy_connect(int fd[2], const char *prog, char *host, char *path)
+{
+       char *port = STR(DEFAULT_GIT_PORT);
+       char *colon, *end;
+       int pipefd[2][2];
+       pid_t pid;
+
+       if (host[0] == '[') {
+               end = strchr(host + 1, ']');
+               if (end) {
+                       *end = 0;
+                       end++;
+                       host++;
+               } else
+                       end = host;
+       } else
+               end = host;
+       colon = strchr(end, ':');
+
+       if (colon) {
+               *colon = 0;
+               port = colon + 1;
+       }
+
+       if (pipe(pipefd[0]) < 0 || pipe(pipefd[1]) < 0)
+               die("unable to create pipe pair for communication");
+       pid = fork();
+       if (!pid) {
+               dup2(pipefd[1][0], 0);
+               dup2(pipefd[0][1], 1);
+               close(pipefd[0][0]);
+               close(pipefd[0][1]);
+               close(pipefd[1][0]);
+               close(pipefd[1][1]);
+               execlp(git_proxy_command, git_proxy_command, host, port, NULL);
+               die("exec failed");
+       }
+       fd[0] = pipefd[0][0];
+       fd[1] = pipefd[1][1];
+       close(pipefd[0][1]);
+       close(pipefd[1][0]);
+       packet_write(fd[1], "%s %s\n", prog, path);
+       return pid;
+}
+
 /*
  * Yeah, yeah, fixme. Need to pass in the heads etc.
  */
@@ -493,8 +560,11 @@ int git_connect(int fd[2], char *url, const char *prog)
                *ptr = '\0';
        }
 
-       if (protocol == PROTO_GIT)
+       if (protocol == PROTO_GIT) {
+               if (git_use_proxy())
+                       return git_proxy_connect(fd, prog, host, path);
                return git_tcp_connect(fd, prog, host, path);
+       }
 
        if (pipe(pipefd[0]) < 0 || pipe(pipefd[1]) < 0)
                die("unable to create pipe pair for communication");