1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ 2 #ifndef __LIBPERF_INTERNAL_RC_CHECK_H 3 #define __LIBPERF_INTERNAL_RC_CHECK_H 4 5 #include <stdlib.h> 6 #include <linux/zalloc.h> 7 8 /* 9 * Enable reference count checking implicitly with leak checking, which is 10 * integrated into address sanitizer. 11 */ 12 #if defined(__SANITIZE_ADDRESS__) || defined(LEAK_SANITIZER) || defined(ADDRESS_SANITIZER) 13 #define REFCNT_CHECKING 1 14 #elif defined(__has_feature) 15 #if __has_feature(address_sanitizer) || __has_feature(leak_sanitizer) 16 #define REFCNT_CHECKING 1 17 #endif 18 #endif 19 20 /* 21 * Shared reference count checking macros. 22 * 23 * Reference count checking is an approach to sanitizing the use of reference 24 * counted structs. It leverages address and leak sanitizers to make sure gets 25 * are paired with a put. Reference count checking adds a malloc-ed layer of 26 * indirection on a get, and frees it on a put. A missed put will be reported as 27 * a memory leak. A double put will be reported as a double free. Accessing 28 * after a put will cause a use-after-free and/or a segfault. 29 */ 30 31 #ifndef REFCNT_CHECKING 32 /* Replaces "struct foo" so that the pointer may be interposed. */ 33 #define DECLARE_RC_STRUCT(struct_name) \ 34 struct struct_name 35 36 /* Declare a reference counted struct variable. */ 37 #define RC_STRUCT(struct_name) struct struct_name 38 39 /* 40 * Interpose the indirection. Result will hold the indirection and object is the 41 * reference counted struct. 42 */ 43 #define ADD_RC_CHK(result, object) (result = object, object) 44 45 /* Strip the indirection layer. */ 46 #define RC_CHK_ACCESS(object) object 47 48 /* Frees the object and the indirection layer. */ 49 #define RC_CHK_FREE(object) free(object) 50 51 /* A get operation adding the indirection layer. */ 52 #define RC_CHK_GET(result, object) ADD_RC_CHK(result, object) 53 54 /* A put operation removing the indirection layer. */ 55 #define RC_CHK_PUT(object) {} 56 57 /* Pointer equality when the indirection may or may not be there. */ 58 #define RC_CHK_EQUAL(object1, object2) (object1 == object2) 59 60 #else 61 62 /* Replaces "struct foo" so that the pointer may be interposed. */ 63 #define DECLARE_RC_STRUCT(struct_name) \ 64 struct original_##struct_name; \ 65 struct struct_name { \ 66 struct original_##struct_name *orig; \ 67 }; \ 68 struct original_##struct_name 69 70 /* Declare a reference counted struct variable. */ 71 #define RC_STRUCT(struct_name) struct original_##struct_name 72 73 /* 74 * Interpose the indirection. Result will hold the indirection and object is the 75 * reference counted struct. 76 */ 77 #define ADD_RC_CHK(result, object) \ 78 ( \ 79 object ? (result = malloc(sizeof(*result)), \ 80 result ? (result->orig = object, result) \ 81 : (result = NULL, NULL)) \ 82 : (result = NULL, NULL) \ 83 ) 84 85 /* Strip the indirection layer. */ 86 #define RC_CHK_ACCESS(object) object->orig 87 88 /* Frees the object and the indirection layer. */ 89 #define RC_CHK_FREE(object) \ 90 do { \ 91 zfree(&object->orig); \ 92 free(object); \ 93 } while(0) 94 95 /* A get operation adding the indirection layer. */ 96 #define RC_CHK_GET(result, object) ADD_RC_CHK(result, (object ? object->orig : NULL)) 97 98 /* A put operation removing the indirection layer. */ 99 #define RC_CHK_PUT(object) \ 100 do { \ 101 if (object) { \ 102 object->orig = NULL; \ 103 free(object); \ 104 } \ 105 } while(0) 106 107 /* Pointer equality when the indirection may or may not be there. */ 108 #define RC_CHK_EQUAL(object1, object2) (object1 == object2 || \ 109 (object1 && object2 && object1->orig == object2->orig)) 110 111 #endif 112 113 #endif /* __LIBPERF_INTERNAL_RC_CHECK_H */ 114