[PATCH v4 2/7] cryptodisk: Refactor to discard have_it global

[Glenn Washburn]

The global "have_it" was never used by the crypto-backends, but was used to
determine if a crypto-backend successfully mounted a cryptodisk with a given
uuid. This is not needed however, because grub_device_iterate() will return
1 if and only if grub_cryptodisk_scan_device() returns 1. And
grub_cryptodisk_scan_device() will now only return 1 if a search_uuid has
been specified and a cryptodisk was successfully setup by a crypto-backend.

With this change grub_device_iterate() will return 1 when a crypto device is
successfully decrypted or when the source device has already been
successfully opened. Prior to this change, trying to mount an already
successfully opened device would trigger an error with the message "no such
cryptodisk found", which is at best misleading. The mount should silently
succeed in this case, which is what happens with this patch.

Signed-off-by: Glenn Washburn <development@efficientek.com>
---
 grub-core/disk/cryptodisk.c | 29 ++++++++++++++++++-----------
 include/grub/err.h          |  1 +
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
index 90f82b2d3..9224105ac 100644
--- a/grub-core/disk/cryptodisk.c
+++ b/grub-core/disk/cryptodisk.c
@@ -983,7 +983,7 @@ grub_util_cryptodisk_get_uuid (grub_disk_t disk)
 
 #endif
 
-static int check_boot, have_it;
+static int check_boot;
 static char *search_uuid;
 
 static void
@@ -1005,7 +1005,12 @@ grub_cryptodisk_scan_device_real (const char *name, 
grub_disk_t source)
   dev = grub_cryptodisk_get_by_source_disk (source);
 
   if (dev)
-    return GRUB_ERR_NONE;
+    {
+      if (grub_strcasecmp (search_uuid, dev->uuid) == 0)
+       return GRUB_ERR_NONE;
+      else
+       return GRUB_ERR_EXISTS;
+    }
 
   FOR_CRYPTODISK_DEVS (cr)
   {
@@ -1024,11 +1029,9 @@ grub_cryptodisk_scan_device_real (const char *name, 
grub_disk_t source)
 
     grub_cryptodisk_insert (dev, name, source);
 
-    have_it = 1;
-
     return GRUB_ERR_NONE;
   }
-  return GRUB_ERR_NONE;
+  return grub_error (GRUB_ERR_BAD_MODULE, "no cryptodisk module can handle 
this device");
 }
 
 #ifdef GRUB_UTIL
@@ -1096,10 +1099,14 @@ grub_cryptodisk_scan_device (const char *name,
   err = grub_cryptodisk_scan_device_real (name, source);
 
   grub_disk_close (source);
-  
-  if (err)
+
+  /*
+   * Do not print error when err is GRUB_ERR_BAD_MODULE to avoid many unhelpful
+   * error messages.
+   */
+  if (err != GRUB_ERR_NONE && err != GRUB_ERR_EXISTS && err != 
GRUB_ERR_BAD_MODULE)
     grub_print_error ();
-  return have_it && search_uuid ? 1 : 0;
+  return (err == GRUB_ERR_NONE && search_uuid != NULL);
 }
 
 static grub_err_t
@@ -1110,9 +1117,9 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int 
argc, char **args)
   if (argc < 1 && !state[1].set && !state[2].set)
     return grub_error (GRUB_ERR_BAD_ARGUMENT, "device name required");
 
-  have_it = 0;
   if (state[0].set)
     {
+      int found_uuid;
       grub_cryptodisk_t dev;
 
       dev = grub_cryptodisk_get_by_uuid (args[0]);
@@ -1125,10 +1132,10 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int 
argc, char **args)
 
       check_boot = state[2].set;
       search_uuid = args[0];
-      grub_device_iterate (&grub_cryptodisk_scan_device, NULL);
+      found_uuid = grub_device_iterate (&grub_cryptodisk_scan_device, NULL);
       search_uuid = NULL;
 
-      if (!have_it)
+      if (!found_uuid)
        return grub_error (GRUB_ERR_BAD_ARGUMENT, "no such cryptodisk found");
       return GRUB_ERR_NONE;
     }
diff --git a/include/grub/err.h b/include/grub/err.h
index b08d5d0de..55219cdcc 100644
--- a/include/grub/err.h
+++ b/include/grub/err.h
@@ -57,6 +57,7 @@ typedef enum
     GRUB_ERR_MENU,
     GRUB_ERR_TIMEOUT,
     GRUB_ERR_IO,
+    GRUB_ERR_EXISTS,
     GRUB_ERR_ACCESS_DENIED,
     GRUB_ERR_EXTRACTOR,
     GRUB_ERR_NET_BAD_ADDRESS,
-- 
2.27.0