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util: add type checking to CONTAINER_OF

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Add a SAME_TYPE checking macro and use it to add type validation to
CONTAINER_OF. This is inspired by the Linux container_of implementation.

The check is inhibited when using C++ as __builtin_types_compatible_p is
not available there.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
This commit is contained in:
Fabio Baltieri
2023-08-27 23:20:34 +01:00
committed by Carles Cufí
parent 48c56cebaa
commit 9c5dafed95
1 changed files with 27 additions and 2 deletions
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29
include/zephyr/sys/util.h
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@@ -15,6 +15,7 @@
#define ZEPHYR_INCLUDE_SYS_UTIL_H_
#include <zephyr/sys/util_macro.h>
#include <zephyr/toolchain/common.h>
/* needs to be outside _ASMLANGUAGE so 'true' and 'false' can turn
* into '1' and '0' for asm or linker scripts
@@ -201,6 +202,27 @@ extern "C" {
(POINTER_TO_UINT(ptr) - POINTER_TO_UINT(array)) / sizeof((array)[0]); \
})
/**
* @brief Validate if two entities have a compatible type
*
* @param a the first entity to be compared
* @param a the second entity to be compared
* @return 1 if the two elements are compatible, 0 if they are not
*/
#define SAME_TYPE(a, b) __builtin_types_compatible_p(__typeof__(a), __typeof__(b))
/**
* @brief Validate CONTAINER_OF parameters, only applies to C mode.
*/
#ifndef __cplusplus
#define CONTAINER_OF_VALIDATE(ptr, type, field) \
BUILD_ASSERT(SAME_TYPE(*(ptr), ((type *)0)->field) || \
SAME_TYPE(*(ptr), void), \
"pointer type mismatch in CONTAINER_OF");
#else
#define CONTAINER_OF_VALIDATE(ptr, type, field)
#endif
/**
* @brief Get a pointer to a structure containing the element
*
@@ -222,8 +244,11 @@ extern "C" {
* @param field the name of the field within the struct @p ptr points to
* @return a pointer to the structure that contains @p ptr
*/
#define CONTAINER_OF(ptr, type, field) \
((type *)(((char *)(ptr)) - offsetof(type, field)))
#define CONTAINER_OF(ptr, type, field) \
({ \
CONTAINER_OF_VALIDATE(ptr, type, field) \
((type *)(((char *)(ptr)) - offsetof(type, field))); \
})
/**
* @brief Value of @p x rounded up to the next multiple of @p align.