Allow qemu binary to be overridden at runtime.

3 files changed, 52 insertions, 5 deletions

diff --git a/src/generator.ml b/src/generator.ml
index 3b08993f..beb36708 100755
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -284,6 +284,32 @@ The first character of C<param> string must be a C<-> (dash).
 
 C<value> can be NULL.");
 
+  ("set_qemu", (RErr, [String "qemu"]), -1, [FishAlias "qemu"],
+   [],
+   "set the qemu binary",
+   "\
+Set the qemu binary that we will use.
+
+The default is chosen when the library was compiled by the
+configure script.
+
+You can also override this by setting the C<LIBGUESTFS_QEMU>
+environment variable.
+
+The string C<qemu> is stashed in the libguestfs handle, so the caller
+must make sure it remains valid for the lifetime of the handle.
+
+Setting C<qemu> to C<NULL> restores the default qemu binary.");
+
+  ("get_qemu", (RConstString "qemu", []), -1, [],
+   [],
+   "get the qemu binary",
+   "\
+Return the current qemu binary.
+
+This is always non-NULL.  If it wasn't set already, then this will
+return the default qemu binary name.");
+
   ("set_path", (RErr, [String "path"]), -1, [FishAlias "path"],
    [],
    "set the search path",
diff --git a/src/guestfs-actions.h b/src/guestfs-actions.h
index ae54d3a3..68184bad 100644
--- a/src/guestfs-actions.h
+++ b/src/guestfs-actions.h
@@ -25,6 +25,8 @@ extern int guestfs_kill_subprocess (guestfs_h *handle);
 extern int guestfs_add_drive (guestfs_h *handle, const char *filename);
 extern int guestfs_add_cdrom (guestfs_h *handle, const char *filename);
 extern int guestfs_config (guestfs_h *handle, const char *qemuparam, const char *qemuvalue);
+extern int guestfs_set_qemu (guestfs_h *handle, const char *qemu);
+extern const char *guestfs_get_qemu (guestfs_h *handle);
 extern int guestfs_set_path (guestfs_h *handle, const char *path);
 extern const char *guestfs_get_path (guestfs_h *handle);
 extern int guestfs_set_autosync (guestfs_h *handle, int autosync);
diff --git a/src/guestfs.c b/src/guestfs.c
index 0bec3b74..1642019a 100644
--- a/src/guestfs.c
+++ b/src/guestfs.c
@@ -156,6 +156,7 @@ struct guestfs_h
   int autosync;
 
   const char *path;
+  const char *qemu;
 
   char *last_error;
 
@@ -217,7 +218,9 @@ guestfs_create (void)
 
   str = getenv ("LIBGUESTFS_PATH");
   g->path = str != NULL ? str : GUESTFS_DEFAULT_PATH;
-  /* XXX We should probably make QEMU configurable as well. */
+
+  str = getenv ("LIBGUESTFS_QEMU");
+  g->qemu = str != NULL ? str : QEMU;
 
   g->main_loop = guestfs_get_default_main_loop ();
 
@@ -511,6 +514,22 @@ guestfs_get_path (guestfs_h *g)
   return g->path;
 }
 
+int
+guestfs_set_qemu (guestfs_h *g, const char *qemu)
+{
+  if (qemu == NULL)
+    g->qemu = QEMU;
+  else
+    g->qemu = qemu;
+  return 0;
+}
+
+const char *
+guestfs_get_qemu (guestfs_h *g)
+{
+  return g->qemu;
+}
+
 /* Add a string to the current command line. */
 static void
 incr_cmdline_size (guestfs_h *g)
@@ -715,7 +734,7 @@ guestfs_launch (guestfs_h *g)
     /* Set up the full command line.  Do this in the subprocess so we
      * don't need to worry about cleaning up.
      */
-    g->cmdline[0] = (char *) QEMU;
+    g->cmdline[0] = (char *) g->qemu;
 
     /* Construct the -net channel parameter for qemu. */
     snprintf (vmchannel, sizeof vmchannel,
@@ -752,7 +771,7 @@ guestfs_launch (guestfs_h *g)
     g->cmdline[g->cmdline_size-1] = NULL;
 
     if (g->verbose) {
-      fprintf (stderr, "%s", QEMU);
+      fprintf (stderr, "%s", g->qemu);
       for (i = 0; g->cmdline[i]; ++i)
 	fprintf (stderr, " %s", g->cmdline[i]);
       fprintf (stderr, "\n");
@@ -775,8 +794,8 @@ guestfs_launch (guestfs_h *g)
     setpgid (0, 0);
 #endif
 
-    execv (QEMU, g->cmdline);	/* Run qemu. */
-    perror (QEMU);
+    execv (g->qemu, g->cmdline); /* Run qemu. */
+    perror (g->qemu);
     _exit (1);
   }