[PATCH v3 04/10] kern/misc: Add a format specifier GUIDs.

[Oliver Steffen]

Extend the printf format specifier for pointers (%p) to accept a suffix
specifier G to print GUIDs: %pG can be used to print grub_guid structs.
This does not interfere with the -Wformat checking of gcc.  Note that
the data type is not checked though (%p accepts void*).
---
 grub-core/kern/misc.c | 86 ++++++++++++++++++++++++++++++++-----------
 1 file changed, 65 insertions(+), 21 deletions(-)

diff --git a/grub-core/kern/misc.c b/grub-core/kern/misc.c
index dfae4f9d7..1a8aff543 100644
--- a/grub-core/kern/misc.c
+++ b/grub-core/kern/misc.c
@@ -24,6 +24,7 @@
 #include <grub/term.h>
 #include <grub/env.h>
 #include <grub/i18n.h>
+#include <grub/types.h>
 
 union printf_arg
 {
@@ -34,7 +35,8 @@ union printf_arg
     {
       INT, LONG, LONGLONG,
       UNSIGNED_INT = 3, UNSIGNED_LONG, UNSIGNED_LONGLONG,
-      STRING
+      STRING,
+      GUID
     } type;
   long long ll;
 };
@@ -772,6 +774,9 @@ parse_printf_arg_fmt (const char *fmt0, struct printf_args 
*args,
       switch (c)
        {
        case 'p':
+         if (*(fmt) == 'G')
+           ++fmt;
+         /* Fall through. */
        case 'x':
        case 'X':
        case 'u':
@@ -885,6 +890,10 @@ parse_printf_arg_fmt (const char *fmt0, struct printf_args 
*args,
            args->ptr[curn].type = UNSIGNED_LONGLONG;
          else
            args->ptr[curn].type = UNSIGNED_INT;
+         if (*(fmt) == 'G') {
+           args->ptr[curn].type = GUID;
+           ++fmt;
+         }
          break;
        case 's':
          args->ptr[curn].type = STRING;
@@ -931,6 +940,12 @@ parse_printf_args (const char *fmt0, struct printf_args 
*args, va_list args_in)
        else
          args->ptr[n].ll = va_arg (args_in, unsigned int);
        break;
+      case GUID:
+       if (sizeof (void *) == sizeof (long long))
+         args->ptr[n].ll = va_arg (args_in, long long);
+       else
+         args->ptr[n].ll = va_arg (args_in, unsigned int);
+       break;
       }
 }
 
@@ -943,6 +958,27 @@ write_char (char *str, grub_size_t *count, grub_size_t 
max_len, unsigned char ch
   (*count)++;
 }
 
+static void
+write_number (char *str, grub_size_t *count, grub_size_t max_len, grub_size_t 
format1,
+            char rightfill, char zerofill, char c, long long value)
+{
+  char tmp[32];
+  const char *p = tmp;
+  grub_size_t len;
+  grub_size_t fill;
+
+  len = grub_lltoa (tmp, c, value) - tmp;
+  fill = len < format1 ? format1 - len : 0;
+  if (! rightfill)
+    while (fill--)
+      write_char (str, count, max_len, zerofill);
+  while (*p)
+    write_char (str, count, max_len, *p++);
+  if (rightfill)
+    while (fill--)
+      write_char (str, count, max_len, zerofill);
+}
+
 static int
 grub_vsnprintf_real (char *str, grub_size_t max_len, const char *fmt0,
                     struct printf_args *args)
@@ -1025,31 +1061,39 @@ grub_vsnprintf_real (char *str, grub_size_t max_len, 
const char *fmt0,
       switch (c)
        {
        case 'p':
-         write_char (str, &count, max_len, '0');
-         write_char (str, &count, max_len, 'x');
-         c = 'x';
+         if (*(fmt) == 'G')
+           {
+             ++fmt;
+             grub_guid_t *guid = (grub_guid_t *) curarg;
+             write_number (str, &count, max_len, 8, 0, '0', 'x', 
grub_le_to_cpu32 (guid->data1));
+             write_char (str, &count, max_len, '-');
+             write_number (str, &count, max_len, 4, 0, '0', 'x', 
grub_le_to_cpu16 (guid->data2));
+             write_char (str, &count, max_len, '-');
+             write_number (str, &count, max_len, 4, 0, '0', 'x', 
grub_le_to_cpu16 (guid->data3));
+             write_char (str, &count, max_len, '-');
+             write_number (str, &count, max_len, 2, 0, '0', 'x', 
guid->data4[0]);
+             write_number (str, &count, max_len, 2, 0, '0', 'x', 
guid->data4[1]);
+             write_char (str, &count, max_len, '-');
+             write_number (str, &count, max_len, 2, 0, '0', 'x', 
guid->data4[2]);
+             write_number (str, &count, max_len, 2, 0, '0', 'x', 
guid->data4[3]);
+             write_number (str, &count, max_len, 2, 0, '0', 'x', 
guid->data4[4]);
+             write_number (str, &count, max_len, 2, 0, '0', 'x', 
guid->data4[5]);
+             write_number (str, &count, max_len, 2, 0, '0', 'x', 
guid->data4[6]);
+             write_number (str, &count, max_len, 2, 0, '0', 'x', 
guid->data4[7]);
+             break;
+           }
+         else
+           {
+             write_char (str, &count, max_len, '0');
+             write_char (str, &count, max_len, 'x');
+             c = 'x';
+           }
          /* Fall through. */
        case 'x':
        case 'X':
        case 'u':
        case 'd':
-         {
-           char tmp[32];
-           const char *p = tmp;
-           grub_size_t len;
-           grub_size_t fill;
-
-           len = grub_lltoa (tmp, c, curarg) - tmp;
-           fill = len < format1 ? format1 - len : 0;
-           if (! rightfill)
-             while (fill--)
-               write_char (str, &count, max_len, zerofill);
-           while (*p)
-             write_char (str, &count, max_len, *p++);
-           if (rightfill)
-             while (fill--)
-               write_char (str, &count, max_len, zerofill);
-         }
+         write_number (str, &count, max_len, format1, rightfill, zerofill, c, 
curarg);
          break;
 
        case 'c':
-- 
2.39.2