daemon: Allow -r option to run daemon standalone.

This changes several aspects of the daemon.  Currently:

* sysroot will be "" (ie. operate directly on /)
* CHROOT_IN/CHROOT_OUT are disabled
* autosync doesn't try to unmount everything

3 files changed, 31 insertions, 12 deletions

diff --git a/daemon/daemon.h b/daemon/daemon.h
index da991b17..4a686c09 100644
--- a/daemon/daemon.h
+++ b/daemon/daemon.h
@@ -33,6 +33,8 @@
 /*-- in guestfsd.c --*/
 extern int verbose;
 
+extern int autosync_umount;
+
 extern const char *sysroot;
 extern int sysroot_len;
 
@@ -253,17 +255,21 @@ extern void notify_progress (uint64_t position, uint64_t total);
  */
 #define CHROOT_IN				\
   do {						\
-    int __old_errno = errno;			\
-    if (chroot (sysroot) == -1)			\
-      perror ("CHROOT_IN: sysroot");		\
-    errno = __old_errno;			\
+    if (sysroot_len > 0) {                      \
+      int __old_errno = errno;			\
+      if (chroot (sysroot) == -1)               \
+        perror ("CHROOT_IN: sysroot");		\
+      errno = __old_errno;			\
+    }                                           \
   } while (0)
 #define CHROOT_OUT				\
   do {						\
-    int __old_errno = errno;			\
-    if (chroot (".") == -1)			\
-      perror ("CHROOT_OUT: .");			\
-    errno = __old_errno;			\
+    if (sysroot_len > 0) {                      \
+      int __old_errno = errno;			\
+      if (chroot (".") == -1)			\
+        perror ("CHROOT_OUT: .");               \
+      errno = __old_errno;			\
+    }                                           \
   } while (0)
 
 /* Marks functions which are not implemented.
diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index a8b53e73..8e77cba6 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -118,6 +118,9 @@ winsock_init (void)
 const char *sysroot = "/sysroot"; /* No trailing slash. */
 int sysroot_len = 8;
 
+/* If set (the default), do 'umount-all' when performing autosync. */
+int autosync_umount = 1;
+
 /* Not used explicitly, but required by the gnulib 'error' module. */
 const char *program_name = "guestfsd";
 
@@ -125,13 +128,13 @@ static void
 usage (void)
 {
   fprintf (stderr,
-    "guestfsd [-f|--foreground] [-v|--verbose]\n");
+    "guestfsd [-f|--foreground] [-v|--verbose] [-r]\n");
 }
 
 int
 main (int argc, char *argv[])
 {
-  static const char *options = "fv?";
+  static const char *options = "frv?";
   static const struct option long_options[] = {
     { "foreground", 0, 0, 'f' },
     { "help", 0, 0, '?' },
@@ -173,6 +176,15 @@ main (int argc, char *argv[])
       dont_fork = 1;
       break;
 
+      /* The -r flag is used when running standalone.  It changes
+       * several aspects of the daemon.
+       */
+    case 'r':
+      sysroot = "";
+      sysroot_len = 0;
+      autosync_umount = 0;
+      break;
+
     case 'v':
       verbose = 1;
       break;
diff --git a/daemon/sync.c b/daemon/sync.c
index 25c7de89..8f5a461b 100644
--- a/daemon/sync.c
+++ b/daemon/sync.c
@@ -51,9 +51,10 @@ do_sync (void)
 int
 do_internal_autosync (void)
 {
-  int r;
+  int r = 0;
 
-  r = do_umount_all ();
+  if (autosync_umount)
+    r = do_umount_all ();
 
   sync_disks ();