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/* Copyright (c) 2003-2004, Roger Dingledine
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2020, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file util_bug.h
*
* \brief Macros to manage assertions, fatal and non-fatal.
*
* Guidelines: All the different kinds of assertion in this file are for
* bug-checking only. Don't write code that can assert based on bad inputs.
*
* We provide two kinds of assertion here: "fatal" and "nonfatal". Use
* nonfatal assertions for any bug you can reasonably recover from -- and
* please, try to recover! Many severe bugs in Tor have been caused by using
* a regular assertion when a nonfatal assertion would have been better.
*
* If you need to check a condition with a nonfatal assertion, AND recover
* from that same condition, consider using the BUG() macro inside a
* conditional. For example:
*
* <code>
* // wrong -- use tor_assert_nonfatal() if you just want an assertion.
* BUG(ptr == NULL);
*
* // okay, but needlessly verbose
* tor_assert_nonfatal(ptr != NULL);
* if (ptr == NULL) { ... }
*
* // this is how we do it:
* if (BUG(ptr == NULL)) { ... }
* </code>
**/
#ifndef TOR_UTIL_BUG_H
#define TOR_UTIL_BUG_H
#include "orconfig.h"
#include "lib/cc/compat_compiler.h"
#include "lib/log/log.h"
#include "lib/testsupport/testsupport.h"
/* Replace assert() with a variant that sends failures to the log before
* calling assert() normally.
*/
#ifdef NDEBUG
/* Nobody should ever want to build with NDEBUG set. 99% of our asserts will
* be outside the critical path anyway, so it's silly to disable bug-checking
* throughout the entire program just because a few asserts are slowing you
* down. Profile, optimize the critical path, and keep debugging on.
*
* And I'm not just saying that because some of our asserts check
* security-critical properties.
*/
#error "Sorry; we don't support building with NDEBUG."
#endif /* defined(NDEBUG) */
#if defined(TOR_UNIT_TESTS) && defined(__GNUC__)
/* We define this GCC macro as a replacement for PREDICT_UNLIKELY() in this
* header, so that in our unit test builds, we'll get compiler warnings about
* stuff like tor_assert(n = 5).
*
* The key here is that (e) is wrapped in exactly one layer of parentheses,
* and then passed right to a conditional. If you do anything else to the
* expression here, or introduce any more parentheses, the compiler won't
* help you.
*
* We only do this for the unit-test build case because it interferes with
* the likely-branch labeling. Note below that in the other case, we define
* these macros to just be synonyms for PREDICT_(UN)LIKELY.
*/
#define ASSERT_PREDICT_UNLIKELY_(e) \
( { \
int tor__assert_tmp_value__; \
if (e) \
tor__assert_tmp_value__ = 1; \
else \
tor__assert_tmp_value__ = 0; \
tor__assert_tmp_value__; \
} )
#define ASSERT_PREDICT_LIKELY_(e) ASSERT_PREDICT_UNLIKELY_(e)
#else /* !(defined(TOR_UNIT_TESTS) && defined(__GNUC__)) */
#define ASSERT_PREDICT_UNLIKELY_(e) PREDICT_UNLIKELY(e)
#define ASSERT_PREDICT_LIKELY_(e) PREDICT_LIKELY(e)
#endif /* defined(TOR_UNIT_TESTS) && defined(__GNUC__) */
/* Sometimes we don't want to use assertions during branch coverage tests; it
* leads to tons of unreached branches which in reality are only assertions we
* didn't hit. */
#if defined(TOR_UNIT_TESTS) && defined(DISABLE_ASSERTS_IN_UNIT_TESTS)
#define tor_assert(a) STMT_BEGIN \
(void)(a); \
STMT_END
#define tor_assertf(a, fmt, ...) STMT_BEGIN \
(void)(a); \
(void)(fmt); \
STMT_END
#else /* !(defined(TOR_UNIT_TESTS) && defined(DISABLE_ASSERTS_IN_UNIT_T...)) */
/** Like assert(3), but send assertion failures to the log as well as to
* stderr. */
#define tor_assert(expr) tor_assertf(expr, NULL)
#define tor_assertf(expr, fmt, ...) STMT_BEGIN \
if (ASSERT_PREDICT_LIKELY_(expr)) { \
} else { \
tor_assertion_failed_(SHORT_FILE__, __LINE__, __func__, #expr, \
fmt, ##__VA_ARGS__); \
tor_abort_(); \
} STMT_END
#endif /* defined(TOR_UNIT_TESTS) && defined(DISABLE_ASSERTS_IN_UNIT_TESTS) */
#define tor_assert_unreached() \
STMT_BEGIN { \
tor_assertion_failed_(SHORT_FILE__, __LINE__, __func__, \
"line should be unreached", NULL); \
tor_abort_(); \
} STMT_END
/* Non-fatal bug assertions. The "unreached" variants mean "this line should
* never be reached." The "once" variants mean "Don't log a warning more than
* once".
*
* The 'BUG' macro checks a boolean condition and logs an error message if it
* is true. Example usage:
* if (BUG(x == NULL))
* return -1;
*/
#ifdef __COVERITY__
#undef BUG
// Coverity defines this in global headers; let's override it. This is a
// magic coverity-only preprocessor thing.
#ifndef COCCI
#nodef BUG(x) (x)
#endif
#endif /* defined(__COVERITY__) */
#if defined(__COVERITY__) || defined(__clang_analyzer__)
// We're running with a static analysis tool: let's treat even nonfatal
// assertion failures as something that we need to avoid.
#define ALL_BUGS_ARE_FATAL
#endif
/** Define ALL_BUGS_ARE_FATAL if you want Tor to crash when any problem comes
* up, so you can get a coredump and track things down. */
#ifdef ALL_BUGS_ARE_FATAL
#define tor_assert_nonfatal_unreached() tor_assert(0)
#define tor_assert_nonfatal(cond) tor_assert((cond))
#define tor_assertf_nonfatal(cond, fmt, ...) \
tor_assertf(cond, fmt, ##__VA_ARGS__)
#define tor_assert_nonfatal_unreached_once() tor_assert(0)
#define tor_assert_nonfatal_once(cond) tor_assert((cond))
#define BUG(cond) \
(ASSERT_PREDICT_UNLIKELY_(cond) ? \
(tor_assertion_failed_(SHORT_FILE__,__LINE__,__func__,"!("#cond")",NULL), \
tor_abort_(), 1) \
: 0)
#ifndef COCCI
#define IF_BUG_ONCE(cond) if (BUG(cond))
#endif
#elif defined(TOR_UNIT_TESTS) && defined(DISABLE_ASSERTS_IN_UNIT_TESTS)
#define tor_assert_nonfatal_unreached() STMT_NIL
#define tor_assert_nonfatal(cond) ((void)(cond))
#define tor_assertf_nonfatal(cond, fmt, ...) STMT_BEGIN \
(void)cond; \
(void)fmt; \
STMT_END
#define tor_assert_nonfatal_unreached_once() STMT_NIL
#define tor_assert_nonfatal_once(cond) ((void)(cond))
#define BUG(cond) (ASSERT_PREDICT_UNLIKELY_(cond) ? 1 : 0)
#ifndef COCCI
#define IF_BUG_ONCE(cond) if (BUG(cond))
#endif
#else /* Normal case, !ALL_BUGS_ARE_FATAL, !DISABLE_ASSERTS_IN_UNIT_TESTS */
#define tor_assert_nonfatal_unreached() STMT_BEGIN \
tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, NULL, 0, NULL); \
STMT_END
#define tor_assert_nonfatal(cond) STMT_BEGIN \
if (ASSERT_PREDICT_LIKELY_(cond)) { \
} else { \
tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 0, NULL);\
} \
STMT_END
#define tor_assertf_nonfatal(cond, fmt, ...) STMT_BEGIN \
if (ASSERT_PREDICT_UNLIKELY_(cond)) { \
} else { \
tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 0, \
fmt, ##__VA_ARGS__); \
} \
STMT_END
#define tor_assert_nonfatal_unreached_once() STMT_BEGIN \
static int warning_logged__ = 0; \
if (!warning_logged__) { \
warning_logged__ = 1; \
tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, NULL, 1, NULL); \
} \
STMT_END
#define tor_assert_nonfatal_once(cond) STMT_BEGIN \
static int warning_logged__ = 0; \
if (ASSERT_PREDICT_LIKELY_(cond)) { \
} else if (!warning_logged__) { \
warning_logged__ = 1; \
tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 1, NULL);\
} \
STMT_END
#define BUG(cond) \
(ASSERT_PREDICT_UNLIKELY_(cond) ? \
(tor_bug_occurred_(SHORT_FILE__,__LINE__,__func__,"!("#cond")",0,NULL),1) \
: 0)
#ifndef COCCI
#ifdef __GNUC__
#define IF_BUG_ONCE__(cond,var) \
if (( { \
static int var = 0; \
int bool_result = !!(cond); \
if (bool_result && !var) { \
var = 1; \
tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, \
("!("#cond")"), 1, NULL); \
} \
bool_result; } ))
#else /* !defined(__GNUC__) */
#define IF_BUG_ONCE__(cond,var) \
static int var = 0; \
if ((cond) ? \
(var ? 1 : \
(var=1, \
tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, \
("!("#cond")"), 1, NULL), \
1)) \
: 0)
#endif /* defined(__GNUC__) */
#endif /* !defined(COCCI) */
#define IF_BUG_ONCE_VARNAME_(a) \
warning_logged_on_ ## a ## __
#define IF_BUG_ONCE_VARNAME__(a) \
IF_BUG_ONCE_VARNAME_(a)
/** This macro behaves as 'if (BUG(x))', except that it only logs its
* warning once, no matter how many times it triggers.
*/
#define IF_BUG_ONCE(cond) \
IF_BUG_ONCE__(ASSERT_PREDICT_UNLIKELY_(cond), \
IF_BUG_ONCE_VARNAME__(__LINE__))
#endif /* defined(ALL_BUGS_ARE_FATAL) || ... */
/**
* Use this macro after a nonfatal assertion, and before a case statement
* where you would want to fall through.
*/
#ifdef ALL_BUGS_ARE_FATAL
#define FALLTHROUGH_UNLESS_ALL_BUGS_ARE_FATAL \
abort()
#else
#define FALLTHROUGH_UNLESS_ALL_BUGS_ARE_FATAL FALLTHROUGH
#endif
/** In older code, we used tor_fragile_assert() to mark optional failure
* points. At these points, we could make some debug builds fail.
* (But release builds would continue.)
*
* To get the same behaviour in recent tor versions, define
* ALL_BUGS_ARE_FATAL, and use any non-fatal assertion or *BUG() macro.
*/
#define tor_fragile_assert() tor_assert_nonfatal_unreached_once()
void tor_assertion_failed_(const char *fname, unsigned int line,
const char *func, const char *expr,
const char *fmt, ...)
CHECK_PRINTF(5,6);
void tor_bug_occurred_(const char *fname, unsigned int line,
const char *func, const char *expr,
int once, const char *fmt, ...)
CHECK_PRINTF(6,7);
void tor_abort_(void) ATTR_NORETURN;
#ifdef _WIN32
#define SHORT_FILE__ (tor_fix_source_file(__FILE__))
const char *tor_fix_source_file(const char *fname);
#else
#define SHORT_FILE__ (__FILE__)
#define tor_fix_source_file(s) (s)
#endif /* defined(_WIN32) */
#ifdef TOR_UNIT_TESTS
void tor_capture_bugs_(int n);
void tor_end_capture_bugs_(void);
const struct smartlist_t *tor_get_captured_bug_log_(void);
void tor_set_failed_assertion_callback(void (*fn)(void));
#endif /* defined(TOR_UNIT_TESTS) */
#endif /* !defined(TOR_UTIL_BUG_H) */
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