Implement device name translation. Remove device name hacks in tests.

2 files changed, 57 insertions, 7 deletions

diff --git a/daemon/daemon.h b/daemon/daemon.h
index 8ad7b7c7..c3b91209 100644
--- a/daemon/daemon.h
+++ b/daemon/daemon.h
@@ -22,8 +22,6 @@
 #include <stdarg.h>
 #include <errno.h>
 #include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 
 #include <rpc/types.h>
 #include <rpc/xdr.h>
@@ -51,6 +49,8 @@ extern char **split_lines (char *str);
 
 extern int shell_quote (char *out, int len, const char *in);
 
+extern int device_name_translation (char *device, const char *func);
+
 extern int verbose;
 
 /*-- in proto.c --*/
@@ -120,20 +120,21 @@ extern void reply (xdrproc_t xdrp, char *ret);
     }									\
   } while (0)
 
-/* Helper for functions that need an argument ("path") that is a device.
+/* All functions that need an argument that is a device or partition name
+ * must call this macro.  It checks that the device exists and does
+ * device name translation (described in the guestfs(3) manpage).
+ * Note that the "path" argument may be modified.
+ *
  * NB. Cannot be used for FileIn functions.
  */
 #define IS_DEVICE(path,errcode)						\
   do {									\
-    struct stat statbuf;						\
     if (strncmp ((path), "/dev/", 5) != 0) {				\
       reply_with_error ("%s: %s: expecting a device name", __func__, (path)); \
       return (errcode);							\
     }									\
-    if (stat ((path), &statbuf) == -1) {				\
-      reply_with_perror ("%s: %s", __func__, (path));			\
+    if (device_name_translation ((path), __func__) == -1)		\
       return (errcode);							\
-    }									\
   } while (0)
 
 /* Helper for functions which need either an absolute path in the
diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index 1d740545..2e83b9fa 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -32,6 +32,8 @@
 #include <sys/select.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <ctype.h>
 #include <signal.h>
 
@@ -685,3 +687,50 @@ shell_quote (char *out, int len, const char *in)
 
   return outlen;
 }
+
+/* Perform device name translation.  Don't call this directly -
+ * use the IS_DEVICE macro.
+ *
+ * See guestfs(3) for the algorithm.
+ *
+ * We have to open the device and test for ENXIO, because
+ * the device nodes themselves will exist in the appliance.
+ */
+int
+device_name_translation (char *device, const char *func)
+{
+  int fd;
+
+  fd = open (device, O_RDONLY);
+  if (fd >= 0) {
+    close (fd);
+    return 0;
+  }
+
+  if (errno != ENXIO) {
+  error:
+    reply_with_perror ("%s: %s", func, device);
+    return -1;
+  }
+
+  /* If the name begins with "/dev/sd" then try the alternatives. */
+  if (strncmp (device, "/dev/sd", 7) != 0)
+    goto error;
+
+  device[5] = 'h';		/* /dev/hd (old IDE driver) */
+  fd = open (device, O_RDONLY);
+  if (fd >= 0) {
+    close (fd);
+    return 0;
+  }
+
+  device[5] = 'v';		/* /dev/vd (for virtio devices) */
+  fd = open (device, O_RDONLY);
+  if (fd >= 0) {
+    close (fd);
+    return 0;
+  }
+
+  device[5] = 's';		/* Restore original device name. */
+  goto error;
+}