From 7f39a2104532e38d77a66c15fdb9e33e30ee7004 Mon Sep 17 00:00:00 2001 From: Michal Schmidt Date: Mon, 14 Sep 2015 20:32:17 +0200 Subject: basic: make sure argument of ELEMENTSOF is an array Using ELEMENTSOF on a pointer will result in a compilation error. --- src/basic/macro.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/src/basic/macro.h b/src/basic/macro.h index cbc3ca97b8..fd6224e568 100644 --- a/src/basic/macro.h +++ b/src/basic/macro.h @@ -123,8 +123,11 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) { return 1UL << (sizeof(u) * 8 - __builtin_clzl(u - 1UL)); } -#define ELEMENTSOF(x) (sizeof(x)/sizeof((x)[0])) - +#define ELEMENTSOF(x) \ + __extension__ (__builtin_choose_expr( \ + !__builtin_types_compatible_p(typeof(x), typeof(&*(x))), \ + sizeof(x)/sizeof((x)[0]), \ + (void)0)) /* * container_of - cast a member of a structure out to the containing structure * @ptr: the pointer to the member. -- cgit v1.2.3-54-g00ecf From 34c38d2aaa2535cb40d0157b0e4a84e6be72ee9a Mon Sep 17 00:00:00 2001 From: Michal Schmidt Date: Mon, 14 Sep 2015 15:53:36 +0200 Subject: basic: nicer assert messages Make sure the assert expression is not macro-expanded before stringification. This makes several assertion failure messages more readable. As an example: assert(streq("foo", "bar")); I'd rather see this: Assertion 'streq("foo", "bar")' failed at foo.c:5, function main(). Aborting. ...than this, though awesome, incomprehensible truncated mess: Assertion '(__extension__ ({ size_t __s1_len, __s2_len; (__builtin_constant_p (( "foo")) && __builtin_constant_p (("bar")) && (__s1_len = strlen (("foo")), __s2_ len = strlen (("bar")), (!((size_t)(const void *)((("foo")) + 1) - (size_t)(cons t void *)(("foo")) == 1) || __s1_len >= 4) && (!((size_t)(const void *)((("bar") ) + 1) - (size_t)(const void *)(("bar")) == 1) || __s2_len >= 4)) ? __builtin_st rcmp (("foo"), ("bar")) : (__builtin_constant_p (("foo")) && ((size_t)(const voi d *)((("foo")) + 1) - (size_t)(const void *)(("foo")) == 1) && (__s1_len = strle n (("foo")), __s1_len < 4) ? (__builtin_constant_p (("bar")) && ((size_t)(const void *)((("bar")) + 1) - (size_t)(const void *)(("bar")) == 1) ? __builtin_strcm p (("foo"), ("bar")) : (__extension__ ({ const unsigned char *__s2 = (const unsi gned char *) (const char *) (("bar")); int __result = (((const unsigned char *) (const char *) (("foo")))[0] - __s2[0]); if (__s1_len > 0 && __result == 0) { __ result = (((const unsigned char *) (const char *) (("foo")))[1] - __s2[1]); if ( __s1_len > 1 && __result == 0) { __result = (((const unsigned char *) (const cha r *) (("foo")))[2] - __s2[2]); if (__s1_len > 2 && __result == 0) __result = ((( const unsigned char *) (const char *) (("foo")))[3] - __s2[3]); } } __result; }) )) : (__builtin_constant_p (("bar")) && ((size_t)(const void *)((("bar")) + 1) - (size_t)(const void *)(("bar")) == 1) && (__s2_len = strlen (("bar")), __s2_len < 4) ? (__builtin_constant_p (("foo")) && ((size_t)(const void *)((("foo")) + 1 ) - (size_t)(const void *)(("foo")) == 1) ? __builtin_strcmp (("foo"), ("bar")) : (- (__extension__ ({ const unsigned char *__s2 = (const unsigned char *) (cons t char *) (("foo")); int __result = (((const unsigned char *) (const char *) ((" bar")))[0] - __s2[0]); if (__s2_len > 0 && __result == 0) { __result = (((const unsigned char *) (const char *) (("bar")))[1] - __s2[1]); if (__s2_len > 1 && __ result == 0) { __result = (((const unsigned char *) (const char *) (("bar")))[2] - __s2[2]); if (__s2_len > 2 && __result == 0) --- src/basic/macro.h | 20 +++++++++++--------- src/libsystemd/sd-bus/bus-internal.h | 2 +- 2 files changed, 12 insertions(+), 10 deletions(-) diff --git a/src/basic/macro.h b/src/basic/macro.h index fd6224e568..248f7a86dd 100644 --- a/src/basic/macro.h +++ b/src/basic/macro.h @@ -216,18 +216,20 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) { (__x / __y + !!(__x % __y)); \ }) -#define assert_se(expr) \ +#define assert_message_se(expr, message) \ do { \ if (_unlikely_(!(expr))) \ - log_assert_failed(#expr, __FILE__, __LINE__, __PRETTY_FUNCTION__); \ - } while (false) \ + log_assert_failed(message, __FILE__, __LINE__, __PRETTY_FUNCTION__); \ + } while (false) + +#define assert_se(expr) assert_message_se(expr, #expr) /* We override the glibc assert() here. */ #undef assert #ifdef NDEBUG #define assert(expr) do {} while(false) #else -#define assert(expr) assert_se(expr) +#define assert(expr) assert_message_se(expr, #expr) #endif #define assert_not_reached(t) \ @@ -252,19 +254,19 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) { REENABLE_WARNING #endif -#define assert_log(expr) ((_likely_(expr)) \ - ? (true) \ - : (log_assert_failed_return(#expr, __FILE__, __LINE__, __PRETTY_FUNCTION__), false)) +#define assert_log(expr, message) ((_likely_(expr)) \ + ? (true) \ + : (log_assert_failed_return(message, __FILE__, __LINE__, __PRETTY_FUNCTION__), false)) #define assert_return(expr, r) \ do { \ - if (!assert_log(expr)) \ + if (!assert_log(expr, #expr)) \ return (r); \ } while (false) #define assert_return_errno(expr, r, err) \ do { \ - if (!assert_log(expr)) { \ + if (!assert_log(expr, #expr)) { \ errno = err; \ return (r); \ } \ diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h index 7af61a9433..e399701beb 100644 --- a/src/libsystemd/sd-bus/bus-internal.h +++ b/src/libsystemd/sd-bus/bus-internal.h @@ -396,6 +396,6 @@ int bus_maybe_reply_error(sd_bus_message *m, int r, sd_bus_error *error); #define bus_assert_return(expr, r, error) \ do { \ - if (!assert_log(expr)) \ + if (!assert_log(expr, #expr)) \ return sd_bus_error_set_errno(error, r); \ } while (false) -- cgit v1.2.3-54-g00ecf From a8b626100b88b50c6c73fccf81b278d64e7e25a2 Mon Sep 17 00:00:00 2001 From: Michal Schmidt Date: Mon, 14 Sep 2015 15:53:47 +0200 Subject: basic: nicer xsprintf and xstrftime assert messages It's nicer if the assertion failure message from a bad use of xsprintf actually mentions xsprintf instead of the expression the macro is implemented as. The assert_message_se macro was added in the previous commit as an internal helper, but it can also be used for customizing assertion failure messages like in this case. Example: char buf[10]; xsprintf(buf, "This is a %s message.\n", "long"); Before: Assertion '(size_t) snprintf(buf, ELEMENTSOF(buf), "This is a %s message.\n", "long") < ELEMENTSOF(buf)' failed at foo.c:6, function main(). Aborting. After: Assertion 'xsprintf: buf[] must be big enough' failed at foo.c:6, function main(). Aborting. --- src/basic/time-util.h | 4 +++- src/basic/util.h | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/src/basic/time-util.h b/src/basic/time-util.h index de881e8fe1..1af01541fc 100644 --- a/src/basic/time-util.h +++ b/src/basic/time-util.h @@ -112,6 +112,8 @@ bool timezone_is_valid(const char *name); clockid_t clock_boottime_or_monotonic(void); -#define xstrftime(buf, fmt, tm) assert_se(strftime(buf, ELEMENTSOF(buf), fmt, tm) > 0) +#define xstrftime(buf, fmt, tm) \ + assert_message_se(strftime(buf, ELEMENTSOF(buf), fmt, tm) > 0, \ + "xstrftime: " #buf "[] must be big enough") int get_timezone(char **timezone); diff --git a/src/basic/util.h b/src/basic/util.h index c7dff9a86d..8abaa740b2 100644 --- a/src/basic/util.h +++ b/src/basic/util.h @@ -374,7 +374,9 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(cpu_set_t*, CPU_FREE); cpu_set_t* cpu_set_malloc(unsigned *ncpus); -#define xsprintf(buf, fmt, ...) assert_se((size_t) snprintf(buf, ELEMENTSOF(buf), fmt, __VA_ARGS__) < ELEMENTSOF(buf)) +#define xsprintf(buf, fmt, ...) \ + assert_message_se((size_t) snprintf(buf, ELEMENTSOF(buf), fmt, __VA_ARGS__) < ELEMENTSOF(buf), \ + "xsprintf: " #buf "[] must be big enough") int files_same(const char *filea, const char *fileb); -- cgit v1.2.3-54-g00ecf