rspreload: Make socket_fallback() call more generic

socket_fallback is used to switch from an rsocket to a normal
socket in the case of failures.  Rename the call and make it
more generic, so that it can switch between an rsocket and
a normal socket in either direction.  This will be used to
support fork().

Signed-off-by: Sean Hefty <sean.hefty@intel.com>

diff --git a/src/preload.c b/src/preload.c
index 2750b301b60daf1c7b35ae60be2007b0cc346318..69597e05af1c55eba9aa92b42ddaf59377492f63 100644 (file)
--- a/src/preload.c
+++ b/src/preload.c
@@ -300,6 +300,68 @@ err:
        return ret;
 }
 
+/*
+ * Convert between an rsocket and a normal socket.  The new socket should have the
+ * same settings and bindings as the current socket.  We currently only handle
+ * setting a few of the more common values.
+ */
+static int
+transpose_socket(int index, int *fd, enum fd_type new_type,
+       int (*socket_new)(int domain, int type, int protocol),
+       int (*shutdown_old)(int socket, int how),
+       int (*close_old)(int socket),
+       int (*getsockname_old)(int socket, struct sockaddr *addr,
+                              socklen_t *addrlen),
+       int (*getsockopt_old)(int socket, int level, int optname,
+                             void *optval, socklen_t *optlen),
+       int (*setsockopt_new)(int socket, int level, int optname,
+                             const void *optval, socklen_t optlen),
+       int (*fcntl_old)(int socket, int cmd, ... /* arg */),
+       int (*fcntl_new)(int socket, int cmd, ... /* arg */))
+{
+       socklen_t len = 0;
+       int new_fd, param, ret;
+
+       ret = getsockname_old(*fd, NULL, &len);
+       if (ret)
+               return ret;
+
+       param = (len == sizeof(struct sockaddr_in6)) ? PF_INET6 : PF_INET;
+       new_fd = socket_new(param, SOCK_STREAM, 0);
+       if (new_fd < 0)
+               return new_fd;
+
+       ret = fcntl_old(*fd, F_GETFL);
+       if (ret > 0)
+               ret = fcntl_new(new_fd, F_SETFL, ret);
+       if (ret)
+               goto err;
+
+       len = sizeof param;
+       ret = getsockopt_old(*fd, SOL_SOCKET, SO_REUSEADDR, &param, &len);
+       if (param && !ret)
+               ret = setsockopt_new(new_fd, SOL_SOCKET, SO_REUSEADDR, &param, len);
+       if (ret)
+               goto err;
+
+       len = sizeof param;
+       ret = getsockopt_old(*fd, IPPROTO_TCP, TCP_NODELAY, &param, &len);
+       if (param && !ret)
+               ret = setsockopt_new(new_fd, IPPROTO_TCP, TCP_NODELAY, &param, len);
+       if (ret)
+               goto err;
+
+       shutdown_old(*fd, SHUT_RDWR);
+       close_old(*fd);
+       fd_store(socket, new_fd, new_type);
+       *fd = new_fd;
+       return 0;
+
+err:
+       real_close(new_fd);
+       return ret;
+}
+
 /*
  * Use defaults on failure.
  */