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// SPDX-License-Identifier: GPL-2.0
/*
* KUnit function redirection (static stubbing) API.
*
* Copyright (C) 2022, Google LLC.
* Author: David Gow <davidgow@google.com>
*/
#include <kunit/test.h>
#include <kunit/static_stub.h>
#include "hooks-impl.h"
/* Context for a static stub. This is stored in the resource data. */
struct kunit_static_stub_ctx {
void *real_fn_addr;
void *replacement_addr;
};
static void __kunit_static_stub_resource_free(struct kunit_resource *res)
{
kfree(res->data);
}
/* Matching function for kunit_find_resource(). match_data is real_fn_addr. */
static bool __kunit_static_stub_resource_match(struct kunit *test,
struct kunit_resource *res,
void *match_real_fn_addr)
{
/* This pointer is only valid if res is a static stub resource. */
struct kunit_static_stub_ctx *ctx = res->data;
/* Make sure the resource is a static stub resource. */
if (res->free != &__kunit_static_stub_resource_free)
return false;
return ctx->real_fn_addr == match_real_fn_addr;
}
/* Hook to return the address of the replacement function. */
void *__kunit_get_static_stub_address_impl(struct kunit *test, void *real_fn_addr)
{
struct kunit_resource *res;
struct kunit_static_stub_ctx *ctx;
void *replacement_addr;
res = kunit_find_resource(test,
__kunit_static_stub_resource_match,
real_fn_addr);
if (!res)
return NULL;
ctx = res->data;
replacement_addr = ctx->replacement_addr;
kunit_put_resource(res);
return replacement_addr;
}
void kunit_deactivate_static_stub(struct kunit *test, void *real_fn_addr)
{
struct kunit_resource *res;
KUNIT_ASSERT_PTR_NE_MSG(test, real_fn_addr, NULL,
"Tried to deactivate a NULL stub.");
/* Look up the existing stub for this function. */
res = kunit_find_resource(test,
__kunit_static_stub_resource_match,
real_fn_addr);
/* Error out if the stub doesn't exist. */
KUNIT_ASSERT_PTR_NE_MSG(test, res, NULL,
"Tried to deactivate a nonexistent stub.");
/* Free the stub. We 'put' twice, as we got a reference
* from kunit_find_resource()
*/
kunit_remove_resource(test, res);
kunit_put_resource(res);
}
EXPORT_SYMBOL_GPL(kunit_deactivate_static_stub);
/* Helper function for kunit_activate_static_stub(). The macro does
* typechecking, so use it instead.
*/
void __kunit_activate_static_stub(struct kunit *test,
void *real_fn_addr,
void *replacement_addr)
{
struct kunit_static_stub_ctx *ctx;
struct kunit_resource *res;
KUNIT_ASSERT_PTR_NE_MSG(test, real_fn_addr, NULL,
"Tried to activate a stub for function NULL");
/* If the replacement address is NULL, deactivate the stub. */
if (!replacement_addr) {
kunit_deactivate_static_stub(test, replacement_addr);
return;
}
/* Look up any existing stubs for this function, and replace them. */
res = kunit_find_resource(test,
__kunit_static_stub_resource_match,
real_fn_addr);
if (res) {
ctx = res->data;
ctx->replacement_addr = replacement_addr;
/* We got an extra reference from find_resource(), so put it. */
kunit_put_resource(res);
} else {
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
ctx->real_fn_addr = real_fn_addr;
ctx->replacement_addr = replacement_addr;
res = kunit_alloc_resource(test, NULL,
&__kunit_static_stub_resource_free,
GFP_KERNEL, ctx);
}
}
EXPORT_SYMBOL_GPL(__kunit_activate_static_stub);
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