Allow /dev/null to be added multiple times.

Change the test for duplicate drives so that you're allowed to
add /dev/null multiple times.  This corresponds to traditional
usage.

This amends commit be47b66c3033105a2b880dbc10bfc2b163b7eafe.

2 files changed, 11 insertions, 30 deletions

diff --git a/src/launch.c b/src/launch.c
index 986c459a..e47eda9a 100644
--- a/src/launch.c
+++ b/src/launch.c
@@ -297,6 +297,7 @@ guestfs__add_drive_opts (guestfs_h *g, const char *filename,
   char *name;
   char *abs_path = NULL;
   int use_cache_off;
+  int check_duplicate;
 
   if (check_path(g, filename) == -1)
     return -1;
@@ -336,10 +337,16 @@ guestfs__add_drive_opts (guestfs_h *g, const char *filename,
     }
   }
 
+  /* Make the path canonical, so we can check if the user is trying to
+   * add the same path twice.  Allow /dev/null to be added multiple
+   * times, in accordance with traditional usage.
+   */
   abs_path = realpath (filename, NULL);
+  check_duplicate = STRNEQ (abs_path, "/dev/null");
+
   struct drive **i = &(g->drives);
   while (*i != NULL) {
-    if (STREQ((*i)->path, abs_path)) {
+    if (check_duplicate && STREQ((*i)->path, abs_path)) {
       error (g, _("drive %s can't be added twice"), abs_path);
       goto err_out;
     }
diff --git a/tests/c-api/test-add-drive-opts.c b/tests/c-api/test-add-drive-opts.c
index 0494450e..897c6fac 100644
--- a/tests/c-api/test-add-drive-opts.c
+++ b/tests/c-api/test-add-drive-opts.c
@@ -30,28 +30,6 @@ main (int argc, char *argv[])
 {
   guestfs_h *g;
   int r;
-  FILE *fp;
-
-  fp = fopen ("test1.img", "w");
-  if (fp == NULL) {
-    perror ("test1.img");
-    exit (EXIT_FAILURE);
-  }
-  fclose (fp);
-
-  fp = fopen ("test2.img", "w");
-  if (fp == NULL) {
-    perror ("test2.img");
-    exit (EXIT_FAILURE);
-  }
-  fclose (fp);
-
-  fp = fopen ("test3.img", "w");
-  if (fp == NULL) {
-    perror ("test3.img");
-    exit (EXIT_FAILURE);
-  }
-  fclose (fp);
 
   g = guestfs_create ();
   if (g == NULL) {
@@ -59,15 +37,15 @@ main (int argc, char *argv[])
     exit (EXIT_FAILURE);
   }
 
-  r = guestfs_add_drive_opts (g, "test1.img", -1);
+  r = guestfs_add_drive_opts (g, "/dev/null", -1);
   if (r == -1)
     exit (EXIT_FAILURE);
-  r = guestfs_add_drive_opts (g, "test2.img",
+  r = guestfs_add_drive_opts (g, "/dev/null",
                               GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
                               -1);
   if (r == -1)
     exit (EXIT_FAILURE);
-  r = guestfs_add_drive_opts (g, "test3.img",
+  r = guestfs_add_drive_opts (g, "/dev/null",
                               GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
                               GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
                               -1);
@@ -76,9 +54,5 @@ main (int argc, char *argv[])
 
   guestfs_close (g);
 
-  unlink ("test1.img");
-  unlink ("test2.img");
-  unlink ("test3.img");
-
   exit (EXIT_SUCCESS);
 }