Add first cut at "git protocol" connect logic.

Useful for pulling stuff off a dedicated server.  Instead of connecting
with ssh or just starting a local pipeline, we connect over TCP to the
other side and try to see if there's a git server listening.

Of course, since I haven't written the git server yet, that will never
happen.  But the server really just needs to listen on a port, and
execute a "git-upload-pack" when somebody connects.

(It should read one packet-line, which should be of the format

	"git-upload-pack directoryname\n"

and eventually we migth have other commands the server might accept).

diff --git a/cache.h b/cache.h
index 1376700..a42ce7e 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -41,6 +41,16 @@
 #endif
 
 /*
+ * Intensive research over the course of many years has shown that
+ * port 9418 is totally unused by anything else. Or
+ *
+ *     Your search - "port 9418" - did not match any documents.
+ *
+ * as www.google.com puts it.
+ */
+#define DEFAULT_GIT_PORT 9418
+
+/*
  * Environment variables transition.
  * We accept older names for now but warn.
  */

diff --git a/connect.c b/connect.c
index b508be3..f01b547 100644 (file)
--- a/connect.c
+++ b/connect.c
@@ -2,6 +2,10 @@
 #include "pkt-line.h"
 #include "quote.h"
 #include <sys/wait.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
 
 int get_ack(int fd, unsigned char *result_sha1)
 {
@@ -42,25 +46,100 @@ int path_match(const char *path, int nr, char **match)
        return 0;
 }
 
+enum protocol {
+       PROTO_LOCAL = 1,
+       PROTO_SSH,
+       PROTO_GIT,
+};
+
+static enum protocol get_protocol(const char *name)
+{
+       if (!strcmp(name, "ssh"))
+               return PROTO_SSH;
+       if (!strcmp(name, "git"))
+               return PROTO_GIT;
+       die("I don't handle protocol '%s'", name);
+}
+
+static void lookup_host(const char *host, struct sockaddr *in)
+{
+       struct addrinfo *res;
+       int ret;
+
+       ret = getaddrinfo(host, NULL, NULL, &res);
+       if (ret)
+               die("Unable to look up %s (%s)", host, gai_strerror(ret));
+       *in = *res->ai_addr;
+       freeaddrinfo(res);
+}
+
+static int git_tcp_connect(int fd[2], const char *prog, char *host, char *path)
+{
+       struct sockaddr addr;
+       int port = DEFAULT_GIT_PORT, sockfd;
+       char *colon;
+
+       colon = strchr(host, ':');
+       if (colon) {
+               char *end;
+               unsigned long n = strtoul(colon+1, &end, 0);
+               if (colon[1] && !*end) {
+                       *colon = 0;
+                       port = n;
+               }
+       }
+
+       lookup_host(host, &addr);
+       ((struct sockaddr_in *)&addr)->sin_port = htons(port);
+
+       sockfd = socket(PF_INET, SOCK_STREAM, IPPROTO_IP);
+       if (sockfd < 0)
+               die("unable to create socket (%s)", strerror(errno));
+       if (connect(sockfd, (void *)&addr, sizeof(addr)) < 0)
+               die("unable to connect (%s)", strerror(errno));
+       fd[0] = sockfd;
+       fd[1] = sockfd;
+       packet_write(sockfd, "%s %s\n", prog, path);
+       return 0;
+}
+
 /*
  * Yeah, yeah, fixme. Need to pass in the heads etc.
  */
 int git_connect(int fd[2], char *url, const char *prog)
 {
        char command[1024];
-       const char *host, *path;
+       char *host, *path;
        char *colon;
        int pipefd[2][2];
        pid_t pid;
+       enum protocol protocol;
 
        host = NULL;
        path = url;
        colon = strchr(url, ':');
+       protocol = PROTO_LOCAL;
        if (colon) {
                *colon = 0;
                host = url;
                path = colon+1;
+               protocol = PROTO_SSH;
+               if (!memcmp(path, "//", 2)) {
+                       char *slash = strchr(path + 2, '/');
+                       if (slash) {
+                               int nr = slash - path - 2;
+                               memmove(path, path+2, nr);
+                               path[nr] = 0;
+                               protocol = get_protocol(url);
+                               host = path;
+                               path = slash;
+                       }
+               }
        }
+
+       if (protocol == PROTO_GIT)
+               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");
        pid = fork();
@@ -73,7 +152,7 @@ int git_connect(int fd[2], char *url, const char *prog)
                close(pipefd[0][1]);
                close(pipefd[1][0]);
                close(pipefd[1][1]);
-               if (host)
+               if (protocol == PROTO_SSH)
                        execlp("ssh", "ssh", host, command, NULL);
                else
                        execlp("sh", "sh", "-c", command, NULL);