|
 |
e28c09 |
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
|
|
|
e28c09 |
From: Peter Jones <pjones@redhat.com>
|
|
|
e28c09 |
Date: Mon, 21 Mar 2022 16:06:10 -0400
|
|
|
e28c09 |
Subject: [PATCH] misc: Make grub_min() and grub_max() more resilient.
|
|
|
e28c09 |
|
|
|
e28c09 |
grub_min(a,b) and grub_max(a,b) use a relatively naive implementation
|
|
|
e28c09 |
which leads to several problems:
|
|
|
e28c09 |
- they evaluate their parameters more than once
|
|
|
e28c09 |
- the naive way to address this, to declare temporary variables in a
|
|
|
e28c09 |
statement-expression, isn't resilient against nested uses, because
|
|
|
e28c09 |
MIN(a,MIN(b,c)) results in the temporary variables being declared in
|
|
|
e28c09 |
two nested scopes, which may result in a build warning depending on
|
|
|
e28c09 |
your build options.
|
|
|
e28c09 |
|
|
|
e28c09 |
This patch changes our implementation to use a statement-expression
|
|
|
e28c09 |
inside a helper macro, and creates the symbols for the temporary
|
|
|
e28c09 |
variables with __COUNTER__ (A GNU C cpp extension) and token pasting to
|
|
|
e28c09 |
create uniquely named internal variables.
|
|
|
e28c09 |
|
|
|
e28c09 |
Signed-off-by: Peter Jones <pjones@redhat.com>
|
|
|
e28c09 |
(cherry picked from commit 2d6800450fa731d7b3ef9893986806e88e819eb6)
|
|
|
e28c09 |
---
|
|
|
e28c09 |
grub-core/loader/multiboot_elfxx.c | 4 +---
|
|
|
e28c09 |
include/grub/misc.h | 25 +++++++++++++++++++++++--
|
|
|
e28c09 |
2 files changed, 24 insertions(+), 5 deletions(-)
|
|
|
e28c09 |
|
|
|
e28c09 |
diff --git a/grub-core/loader/multiboot_elfxx.c b/grub-core/loader/multiboot_elfxx.c
|
|
|
e28c09 |
index f2318e0d16..87f6e31aa6 100644
|
|
|
e28c09 |
--- a/grub-core/loader/multiboot_elfxx.c
|
|
|
e28c09 |
+++ b/grub-core/loader/multiboot_elfxx.c
|
|
|
e28c09 |
@@ -35,9 +35,7 @@
|
|
|
e28c09 |
#endif
|
|
|
e28c09 |
|
|
|
e28c09 |
#include <grub/i386/relocator.h>
|
|
|
e28c09 |
-
|
|
|
e28c09 |
-#define CONCAT(a,b) CONCAT_(a, b)
|
|
|
e28c09 |
-#define CONCAT_(a,b) a ## b
|
|
|
e28c09 |
+#include <grub/misc.h>
|
|
|
e28c09 |
|
|
|
e28c09 |
#pragma GCC diagnostic ignored "-Wcast-align"
|
|
|
e28c09 |
|
|
|
e28c09 |
diff --git a/include/grub/misc.h b/include/grub/misc.h
|
|
|
e28c09 |
index 6c4aa85ac5..cf84aec1db 100644
|
|
|
e28c09 |
--- a/include/grub/misc.h
|
|
|
e28c09 |
+++ b/include/grub/misc.h
|
|
|
e28c09 |
@@ -35,6 +35,14 @@
|
|
|
e28c09 |
#define ARRAY_SIZE(array) (sizeof (array) / sizeof (array[0]))
|
|
|
e28c09 |
#define COMPILE_TIME_ASSERT(cond) switch (0) { case 1: case !(cond): ; }
|
|
|
e28c09 |
|
|
|
e28c09 |
+#ifndef CONCAT_
|
|
|
e28c09 |
+#define CONCAT_(a, b) a ## b
|
|
|
e28c09 |
+#endif
|
|
|
e28c09 |
+
|
|
|
e28c09 |
+#ifndef CONCAT
|
|
|
e28c09 |
+#define CONCAT(a, b) CONCAT_(a, b)
|
|
|
e28c09 |
+#endif
|
|
|
e28c09 |
+
|
|
|
e28c09 |
#define grub_dprintf(condition, ...) grub_real_dprintf(GRUB_FILE, __LINE__, condition, __VA_ARGS__)
|
|
|
e28c09 |
|
|
|
e28c09 |
void *EXPORT_FUNC(grub_memmove) (void *dest, const void *src, grub_size_t n);
|
|
|
e28c09 |
@@ -498,8 +506,21 @@ void EXPORT_FUNC(grub_real_boot_time) (const char *file,
|
|
|
e28c09 |
#define grub_boot_time(...)
|
|
|
e28c09 |
#endif
|
|
|
e28c09 |
|
|
|
e28c09 |
-#define grub_max(a, b) (((a) > (b)) ? (a) : (b))
|
|
|
e28c09 |
-#define grub_min(a, b) (((a) < (b)) ? (a) : (b))
|
|
|
e28c09 |
+#define _grub_min(a, b, _a, _b) \
|
|
|
e28c09 |
+ ({ typeof (a) _a = (a); \
|
|
|
e28c09 |
+ typeof (b) _b = (b); \
|
|
|
e28c09 |
+ _a < _b ? _a : _b; })
|
|
|
e28c09 |
+#define grub_min(a, b) _grub_min(a, b, \
|
|
|
e28c09 |
+ CONCAT(_a_,__COUNTER__), \
|
|
|
e28c09 |
+ CONCAT(_b_,__COUNTER__))
|
|
|
e28c09 |
+
|
|
|
e28c09 |
+#define _grub_max(a, b, _a, _b) \
|
|
|
e28c09 |
+ ({ typeof (a) _a = (a); \
|
|
|
e28c09 |
+ typeof (b) _b = (b); \
|
|
|
e28c09 |
+ _a > _b ? _a : _b; })
|
|
|
e28c09 |
+#define grub_max(a, b) _grub_max(a, b, \
|
|
|
e28c09 |
+ CONCAT(_a_,__COUNTER__), \
|
|
|
e28c09 |
+ CONCAT(_b_,__COUNTER__))
|
|
|
e28c09 |
|
|
|
e28c09 |
#define grub_log2ull(n) (GRUB_TYPE_BITS (grub_uint64_t) - __builtin_clzll (n) - 1)
|
|
|
e28c09 |
|