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static-destruct: introduce STATIC_ARRAY_DESTRUCTOR_REGISTER()

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This commit is contained in:
Yu Watanabe
2023-05-09 17:53:42 +09:00
parent 555ead8985
commit 9695b0c01b
2 changed files with 85 additions and 10 deletions
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src/basic/static-destruct.h
+46 -4
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@@ -4,6 +4,7 @@
#include "alloc-util.h"
#include "macro.h"
#include "memory-util.h"
/* A framework for registering static variables that shall be freed on shutdown of a process. It's a bit like gcc's
* destructor attribute, but allows us to precisely schedule when we want to free the variables. This is supposed to
@@ -25,9 +26,24 @@
* packed next to each other so that we can enumerate it. */ \
_variable_no_sanitize_address_
typedef struct StaticDestructor {
typedef enum StaticDestructorType {
STATIC_DESTRUCTOR_SIMPLE,
STATIC_DESTRUCTOR_ARRAY,
_STATIC_DESTRUCTOR_TYPE_MAX,
_STATIC_DESTRUCTOR_INVALID = -EINVAL,
} StaticDestructorType;
typedef struct SimpleCleanup {
void *data;
free_func_t destroy;
} SimpleCleanup;
typedef struct StaticDestructor {
StaticDestructorType type;
union {
SimpleCleanup simple;
ArrayCleanup array;
};
} StaticDestructor;
#define STATIC_DESTRUCTOR_REGISTER(variable, func) \
@@ -41,10 +57,25 @@ typedef struct StaticDestructor {
} \
_common_static_destruct_attrs_ \
static const StaticDestructor UNIQ_T(static_destructor_entry, uq) = { \
.data = &(variable), \
.destroy = UNIQ_T(static_destructor_wrapper, uq), \
.type = STATIC_DESTRUCTOR_SIMPLE, \
.simple.data = &(variable), \
.simple.destroy = UNIQ_T(static_destructor_wrapper, uq), \
}
#define STATIC_ARRAY_DESTRUCTOR_REGISTER(a, n, func) \
_STATIC_ARRAY_DESTRUCTOR_REGISTER(UNIQ, a, n, func)
#define _STATIC_ARRAY_DESTRUCTOR_REGISTER(uq, a, n, func) \
/* Type-safety check */ \
_unused_ static void (* UNIQ_T(static_destructor_wrapper, uq))(typeof(a[0]) *x, size_t y) = (func); \
_common_static_destruct_attrs_ \
static const StaticDestructor UNIQ_T(static_destructor_entry, uq) = { \
.type = STATIC_DESTRUCTOR_ARRAY, \
.array.parray = (void**) &(a), \
.array.pn = &(n), \
.array.pfunc = (free_array_func_t) (func), \
};
/* Beginning and end of our section listing the destructors. We define these as weak as we want this to work
* even if no destructors are defined and the section is missing. */
extern const StaticDestructor _weak_ __start_SYSTEMD_STATIC_DESTRUCT[];
@@ -59,5 +90,16 @@ static inline void static_destruct(void) {
for (const StaticDestructor *d = ALIGN_PTR(__start_SYSTEMD_STATIC_DESTRUCT);
d < __stop_SYSTEMD_STATIC_DESTRUCT;
d = ALIGN_PTR(d + 1))
d->destroy(d->data);
switch (d->type) {
case STATIC_DESTRUCTOR_SIMPLE:
d->simple.destroy(d->simple.data);
break;
case STATIC_DESTRUCTOR_ARRAY:
array_cleanup(&d->array);
break;
default:
assert_not_reached();
}
}