Re: [PATCH v1 10/10] efivars: use generic UUID library

On Thu, 2016-02-18 at 15:07 +0000, Matt Fleming wrote:

On Wed, 17 Feb, at 02:17:28PM, Andy Shevchenko wrote:

quoted

Instead of opencoding let's use generic UUID library functions
here.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 fs/efivarfs/inode.c | 40 +++-------------------------------------
 1 file changed, 3 insertions(+), 37 deletions(-)

diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index 3381b9d..b579e3a 100644
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c

@@ -11,6 +11,7 @@

 #include <linux/fs.h>
 #include <linux/ctype.h>
 #include <linux/slab.h>
+#include <linux/uuid.h>
 
 #include "internal.h"
 

@@ -44,11 +45,7 @@ struct inode *efivarfs_get_inode(struct

super_block *sb,
  */
 bool efivarfs_valid_name(const char *str, int len)
 {
-	static const char dashes[EFI_VARIABLE_GUID_LEN] = {
-		[8] = 1, [13] = 1, [18] = 1, [23] = 1
-	};
 	const char *s = str + len - EFI_VARIABLE_GUID_LEN;
-	int i;
 
 	/*
 	 * We need a GUID, plus at least one letter for the
variable name,

@@ -66,37 +63,7 @@ bool efivarfs_valid_name(const char *str, int

len)
 	 *
 	 *	12345678-1234-1234-1234-123456789abc
 	 */
-	for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) {
-		if (dashes[i]) {
-			if (*s++ != '-')
-				return false;
-		} else {
-			if (!isxdigit(*s++))
-				return false;
-		}
-	}
-
-	return true;
-}
-
-static void efivarfs_hex_to_guid(const char *str, efi_guid_t
*guid)
-{
-	guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
-	guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
-	guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
-	guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
-	guid->b[4] = hex_to_bin(str[11]) << 4 |
hex_to_bin(str[12]);
-	guid->b[5] = hex_to_bin(str[9]) << 4 |
hex_to_bin(str[10]);
-	guid->b[6] = hex_to_bin(str[16]) << 4 |
hex_to_bin(str[17]);
-	guid->b[7] = hex_to_bin(str[14]) << 4 |
hex_to_bin(str[15]);
-	guid->b[8] = hex_to_bin(str[19]) << 4 |
hex_to_bin(str[20]);
-	guid->b[9] = hex_to_bin(str[21]) << 4 |
hex_to_bin(str[22]);
-	guid->b[10] = hex_to_bin(str[24]) << 4 |
hex_to_bin(str[25]);
-	guid->b[11] = hex_to_bin(str[26]) << 4 |
hex_to_bin(str[27]);
-	guid->b[12] = hex_to_bin(str[28]) << 4 |
hex_to_bin(str[29]);
-	guid->b[13] = hex_to_bin(str[30]) << 4 |
hex_to_bin(str[31]);
-	guid->b[14] = hex_to_bin(str[32]) << 4 |
hex_to_bin(str[33]);
-	guid->b[15] = hex_to_bin(str[34]) << 4 |
hex_to_bin(str[35]);
+	return uuid_is_valid(s);
 }

I think you've confused yourself here. You've inverted the return
value meaning for efivarfs_valid_name().

Normally I would expect this change to be correct but uuid_is_valid()
returns 0 for success, -EINVAL for failure. Either the function is
misnamed or the return value semantics are wrong.

Oops, thanks for noticing this. Right the return value should be
aligned.

-- 
Andy Shevchenko [off-list ref]
Intel Finland Oy

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