mini-os: make frontends and xenbus optional

This adds compile-time logic to disable certain frontends in mini-os:
 - pcifront is disabled by default, enabled for ioemu
 - blkfront, netfront, fbfront, kbdfront, consfront are enabled by default
 - xenbus is required for any frontend, and is enabled by default

If all frontends and xenbus are disabled, mini-os will run without
needing to communicate with xenstore, making it suitable to run the
xenstore daemon. The console frontend is not required for the initial
console, only consoles opened via openpt or ptmx.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/extras/mini-os/lib/sys.c b/extras/mini-os/lib/sys.c
index 2329a78c21..5875797f48 100644
--- a/extras/mini-os/lib/sys.c
+++ b/extras/mini-os/lib/sys.c
@@ -164,6 +164,7 @@ int mkdir(const char *pathname, mode_t mode)
     return -1;
 }
 
+#ifdef CONFIG_CONSFRONT
 int posix_openpt(int flags)
 {
     struct consfront_dev *dev;
@@ -192,6 +193,18 @@ int open_savefile(const char *path, int save)
     printk("fd(%d) = open_savefile\n", dev->fd);
     return(dev->fd);
 }
+#else
+int posix_openpt(int flags)
+{
+	errno = EIO;
+	return -1;
+}
+int open_savefile(const char *path, int save)
+{
+	errno = EIO;
+	return -1;
+}
+#endif
 
 int open(const char *pathname, int flags, ...)
 {
@@ -241,6 +254,7 @@ int read(int fd, void *buf, size_t nbytes)
 	case FTYPE_SOCKET:
 	    return lwip_read(files[fd].socket.fd, buf, nbytes);
 #endif
+#ifdef CONFIG_NETFRONT
 	case FTYPE_TAP: {
 	    ssize_t ret;
 	    ret = netfront_receive(files[fd].tap.dev, buf, nbytes);
@@ -250,6 +264,8 @@ int read(int fd, void *buf, size_t nbytes)
 	    }
 	    return ret;
 	}
+#endif
+#ifdef CONFIG_KBDFRONT
         case FTYPE_KBD: {
             int ret, n;
             n = nbytes / sizeof(union xenkbd_in_event);
@@ -260,6 +276,8 @@ int read(int fd, void *buf, size_t nbytes)
 	    }
 	    return ret * sizeof(union xenkbd_in_event);
         }
+#endif
+#ifdef CONFIG_FBFRONT
         case FTYPE_FB: {
             int ret, n;
             n = nbytes / sizeof(union xenfb_in_event);
@@ -270,6 +288,7 @@ int read(int fd, void *buf, size_t nbytes)
 	    }
 	    return ret * sizeof(union xenfb_in_event);
         }
+#endif
 	default:
 	    break;
     }
@@ -297,9 +316,11 @@ int write(int fd, const void *buf, size_t nbytes)
 	case FTYPE_SOCKET:
 	    return lwip_write(files[fd].socket.fd, (void*) buf, nbytes);
 #endif
+#ifdef CONFIG_NETFRONT
 	case FTYPE_TAP:
 	    netfront_xmit(files[fd].tap.dev, (void*) buf, nbytes);
 	    return nbytes;
+#endif
 	default:
 	    break;
     }
@@ -326,9 +347,11 @@ int close(int fd)
         default:
 	    files[fd].type = FTYPE_NONE;
 	    return 0;
+#ifdef CONFIG_XENBUS
 	case FTYPE_XENBUS:
             xs_daemon_close((void*)(intptr_t) fd);
             return 0;
+#endif
 #ifdef HAVE_LWIP
 	case FTYPE_SOCKET: {
 	    int res = lwip_close(files[fd].socket.fd);
@@ -345,27 +368,37 @@ int close(int fd)
 	case FTYPE_GNTMAP:
 	    minios_gnttab_close_fd(fd);
 	    return 0;
+#ifdef CONFIG_NETFRONT
 	case FTYPE_TAP:
 	    shutdown_netfront(files[fd].tap.dev);
 	    files[fd].type = FTYPE_NONE;
 	    return 0;
+#endif
+#ifdef CONFIG_BLKFRONT
 	case FTYPE_BLK:
             shutdown_blkfront(files[fd].blk.dev);
 	    files[fd].type = FTYPE_NONE;
 	    return 0;
+#endif
+#ifdef CONFIG_KBDFRONT
 	case FTYPE_KBD:
             shutdown_kbdfront(files[fd].kbd.dev);
             files[fd].type = FTYPE_NONE;
             return 0;
+#endif
+#ifdef CONFIG_FBFRONT
 	case FTYPE_FB:
             shutdown_fbfront(files[fd].fb.dev);
             files[fd].type = FTYPE_NONE;
             return 0;
+#endif
+#ifdef CONFIG_CONSFRONT
         case FTYPE_SAVEFILE:
         case FTYPE_CONSOLE:
             fini_console(files[fd].cons.dev);
             files[fd].type = FTYPE_NONE;
             return 0;
+#endif
 	case FTYPE_NONE:
 	    break;
     }
@@ -611,6 +644,7 @@ static int select_poll(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exce
                 n++;
 	    FD_CLR(i, exceptfds);
 	    break;
+#ifdef CONFIG_XENBUS
 	case FTYPE_XENBUS:
 	    if (FD_ISSET(i, readfds)) {
                 if (files[i].xenbus.events)
@@ -621,6 +655,7 @@ static int select_poll(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exce
 	    FD_CLR(i, writefds);
 	    FD_CLR(i, exceptfds);
 	    break;
+#endif
 	case FTYPE_EVTCHN:
 	case FTYPE_TAP:
 	case FTYPE_BLK:
@@ -705,11 +740,19 @@ int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
     fd_set myread, mywrite, myexcept;
     struct thread *thread = get_current();
     s_time_t start = NOW(), stop;
+#ifdef CONFIG_NETFRONT
     DEFINE_WAIT(netfront_w);
+#endif
     DEFINE_WAIT(event_w);
+#ifdef CONFIG_BLKFRONT
     DEFINE_WAIT(blkfront_w);
+#endif
+#ifdef CONFIG_XENBUS
     DEFINE_WAIT(xenbus_watch_w);
+#endif
+#ifdef CONFIG_KBDFRONT
     DEFINE_WAIT(kbdfront_w);
+#endif
     DEFINE_WAIT(console_w);
 
     assert(thread == main_thread);
@@ -727,11 +770,19 @@ int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
     /* Tell people we're going to sleep before looking at what they are
      * saying, hence letting them wake us if events happen between here and
      * schedule() */
+#ifdef CONFIG_NETFRONT
     add_waiter(netfront_w, netfront_queue);
+#endif
     add_waiter(event_w, event_queue);
+#ifdef CONFIG_BLKFRONT
     add_waiter(blkfront_w, blkfront_queue);
+#endif
+#ifdef CONFIG_XENBUS
     add_waiter(xenbus_watch_w, xenbus_watch_queue);
+#endif
+#ifdef CONFIG_KBDFRONT
     add_waiter(kbdfront_w, kbdfront_queue);
+#endif
     add_waiter(console_w, console_queue);
 
     if (readfds)
@@ -814,11 +865,19 @@ int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
     ret = -1;
 
 out:
+#ifdef CONFIG_NETFRONT
     remove_waiter(netfront_w, netfront_queue);
+#endif
     remove_waiter(event_w, event_queue);
+#ifdef CONFIG_BLKFRONT
     remove_waiter(blkfront_w, blkfront_queue);
+#endif
+#ifdef CONFIG_XENBUS
     remove_waiter(xenbus_watch_w, xenbus_watch_queue);
+#endif
+#ifdef CONFIG_KBDFRONT
     remove_waiter(kbdfront_w, kbdfront_queue);
+#endif
     remove_waiter(console_w, console_queue);
     return ret;
 }