2 * The UCW Library -- Miscellaneous Functions
4 * (c) 1997--2009 Martin Mares <mj@ucw.cz>
5 * (c) 2005 Tomas Valla <tom@ucw.cz>
6 * (c) 2006 Robert Spalek <robert@ucw.cz>
7 * (c) 2007 Pavel Charvat <pchar@ucw.cz>
9 * This software may be freely distributed and used according to the terms
10 * of the GNU Lesser General Public License.
16 #include <ucw/config.h>
19 /*** === Macros for handling structures, offsets and alignment ***/
21 #define CHECK_PTR_TYPE(x, type) ((x)-(type)(x) + (type)(x)) /** Check that a pointer @x is of type @type. Fail compilation if not. **/
22 #define PTR_TO(s, i) &((s*)0)->i /** Return OFFSETOF() in form of a pointer. **/
23 #define OFFSETOF(s, i) ((uns)offsetof(s, i)) /** Offset of item @i from the start of structure @s **/
24 #define SKIP_BACK(s, i, p) ((s *)((char *)p - OFFSETOF(s, i))) /** Given a pointer @p to item @i of structure @s, return a pointer to the start of the struct. **/
26 /** Align an integer @s to the nearest higher multiple of @a (which should be a power of two) **/
27 #define ALIGN_TO(s, a) (((s)+a-1)&~(a-1))
29 /** Align a pointer @p to the nearest higher multiple of @s. **/
30 #define ALIGN_PTR(p, s) ((uintptr_t)(p) % (s) ? (typeof(p))((uintptr_t)(p) + (s) - (uintptr_t)(p) % (s)) : (p))
32 #define UNALIGNED_PART(ptr, type) (((uintptr_t) (ptr)) % sizeof(type))
34 /*** === Other utility macros ***/
36 #define MIN(a,b) (((a)<(b))?(a):(b)) /** Minimum of two numbers **/
37 #define MAX(a,b) (((a)>(b))?(a):(b)) /** Maximum of two numbers **/
38 #define CLAMP(x,min,max) ({ int _t=x; (_t < min) ? min : (_t > max) ? max : _t; }) /** Clip a number @x to interval [@min,@max] **/
39 #define ABS(x) ((x) < 0 ? -(x) : (x)) /** Absolute value **/
40 #define ARRAY_SIZE(a) (sizeof(a)/sizeof(*(a))) /** The number of elements of an array **/
41 #define STRINGIFY(x) #x /** Convert macro parameter to a string **/
42 #define STRINGIFY_EXPANDED(x) STRINGIFY(x) /** Convert an expanded macro parameter to a string **/
43 #define GLUE(x,y) x##y /** Glue two tokens together **/
44 #define GLUE_(x,y) x##_##y /** Glue two tokens together, separating them by an underscore **/
46 #define COMPARE(x,y) do { if ((x)<(y)) return -1; if ((x)>(y)) return 1; } while(0) /** Numeric comparison function for qsort() **/
47 #define REV_COMPARE(x,y) COMPARE(y,x) /** Reverse numeric comparison **/
48 #define COMPARE_LT(x,y) do { if ((x)<(y)) return 1; if ((x)>(y)) return 0; } while(0)
49 #define COMPARE_GT(x,y) COMPARE_LT(y,x)
51 #define ROL(x, bits) (((x) << (bits)) | ((uns)(x) >> (sizeof(uns)*8 - (bits)))) /** Bitwise rotation of an unsigned int to the left **/
52 #define ROR(x, bits) (((uns)(x) >> (bits)) | ((x) << (sizeof(uns)*8 - (bits)))) /** Bitwise rotation of an unsigned int to the right **/
54 /*** === Shortcuts for GCC Extensions ***/
59 #define NONRET __attribute__((noreturn)) /** Function does not return **/
60 #define UNUSED __attribute__((unused)) /** Variable/parameter is knowingly unused **/
61 #define CONSTRUCTOR __attribute__((constructor)) /** Call function upon start of program **/
62 #define CONSTRUCTOR_WITH_PRIORITY(p) __attribute__((constructor(p))) /** Define constructor with a given priority **/
63 #define PACKED __attribute__((packed)) /** Structure should be packed **/
64 #define CONST __attribute__((const)) /** Function depends only on arguments **/
65 #define PURE __attribute__((pure)) /** Function depends only on arguments and global vars **/
66 #define FORMAT_CHECK(x,y,z) __attribute__((format(x,y,z))) /** Checking of printf-like format strings **/
67 #define likely(x) __builtin_expect((x),1) /** Use `if (likely(@x))` if @x is almost always true **/
68 #define unlikely(x) __builtin_expect((x),0) /** Use `if (unlikely(@x))` to hint that @x is almost always false **/
70 #if __GNUC__ >= 4 || __GNUC__ == 3 && __GNUC_MINOR__ >= 3
71 #define ALWAYS_INLINE inline __attribute__((always_inline)) /** Forcibly inline **/
72 #define NO_INLINE __attribute__((noinline)) /** Forcibly uninline **/
74 #define ALWAYS_INLINE inline
78 #define LIKE_MALLOC __attribute__((malloc)) /** Function returns a "new" pointer **/
79 #define SENTINEL_CHECK __attribute__((sentinel)) /** The last argument must be NULL **/
82 #define SENTINEL_CHECK
86 #error This program requires the GNU C compiler.
92 * === Basic logging functions (see <<log:,Logging>> and <ucw/log.h> for more)
95 enum log_levels { /** The available log levels to pass to msg() and friends. **/
96 L_DEBUG=0, // 'D' - Debugging
97 L_INFO, // 'I' - Informational
98 L_WARN, // 'W' - Warning
99 L_ERROR, // 'E' - Error, but non-critical
100 L_INFO_R, // 'i' - An alternative set of levels for messages caused by remote events
101 L_WARN_R, // 'w' (e.g., a packet received via network)
103 L_FATAL, // '!' - Fatal error
107 #define LOG_LEVEL_NAMES P(DEBUG) P(INFO) P(WARN) P(ERROR) P(INFO_R) P(WARN_R) P(ERROR_R) P(FATAL)
109 // Return the letter associated with a given severity level
110 #define LS_LEVEL_LETTER(level) ("DIWEiwe!###"[( level )])
112 #define L_SIGHANDLER 0x80000000 /** Avoid operations that are unsafe in signal handlers **/
113 #define L_LOGGER_ERR 0x40000000 /** Used internally to avoid infinite reporting of logging errors **/
116 * This is the basic printf-like function for logging a message.
117 * The @flags contain the log level and possibly other flag bits (like `L_SIGHANDLER`).
119 void msg(uns flags, const char *fmt, ...) FORMAT_CHECK(printf,2,3);
120 void vmsg(uns flags, const char *fmt, va_list args); /** A vararg version of msg(). **/
121 void die(const char *, ...) NONRET FORMAT_CHECK(printf,1,2); /** Log a fatal error message and exit the program. **/
122 void vdie(const char *fmt, va_list args) NONRET; /** va_list version of die() **/
124 extern char *log_title; /** An optional log message title. Set to program name by log_init(). **/
125 extern int log_pid; /** An optional PID printed in each log message. Set to 0 if it shouldn't be logged. **/
126 extern void (*log_die_hook)(void); /** An optional function called just before die() exists. **/
128 void log_init(const char *argv0); /** Set @log_title to the program name extracted from @argv[0]. **/
129 void log_fork(void); /** Call after fork() to update @log_pid. **/
130 void log_file(const char *name); /** Establish logging to the named file. Also redirect stderr there. **/
132 void assert_failed(const char *assertion, const char *file, int line) NONRET;
133 void assert_failed_noinfo(void) NONRET;
137 * Check an assertion. If the condition @x is false, stop the program with a fatal error.
138 * Assertion checks are compiled only when `DEBUG_ASSERTS` is defined.
140 #define ASSERT(x) ({ if (unlikely(!(x))) assert_failed(#x, __FILE__, __LINE__); 1; })
142 #define ASSERT(x) ({ if (__builtin_constant_p(x) && !(x)) assert_failed_noinfo(); 1; })
145 #define COMPILE_ASSERT(name,x) typedef char _COMPILE_ASSERT_##name[!!(x)-1]
148 #define DBG(x,y...) msg(L_DEBUG, x,##y) /** If `LOCAL_DEBUG` is defined before including <ucw/lib.h>, log a debug message. Otherwise do nothing. **/
150 #define DBG(x,y...) do { } while(0)
155 * Sometimes, we may want to check that a pointer points to a valid memory
156 * location before we start using it for anything more complicated. This
157 * macro checks pointer validity by reading the byte it points to.
159 #define ASSERT_READABLE(ptr) ({ volatile char *__p = (ptr); *__p; })
160 /** Like the previous macro, but it checks writeability, too. **/
161 #define ASSERT_WRITEABLE(ptr) ({ volatile char *__p = (ptr); *__p = *__p; })
163 #define ASSERT_READABLE(ptr) do { } while(0)
164 #define ASSERT_WRITEABLE(ptr) do { } while(0)
167 /*** === Memory allocation ***/
170 * Unfortunately, several libraries we might want to link to define
171 * their own xmalloc and we don't want to interfere with them, hence
174 #define xmalloc ucw_xmalloc
175 #define xrealloc ucw_xrealloc
176 #define xfree ucw_xfree
178 void *xmalloc(size_t) LIKE_MALLOC; /** Allocate memory and die() if there is none. **/
179 void *xrealloc(void *, size_t); /** Reallocate memory and die() if there is none. **/
180 void xfree(void *); /** Free memory allocated by xmalloc() or xrealloc(). **/
182 void *xmalloc_zero(size_t) LIKE_MALLOC; /** Allocate memory and fill it by zeroes. **/
183 char *xstrdup(const char *) LIKE_MALLOC; /** Make a xmalloc()'ed copy of a string. Returns NULL for NULL string. **/
187 void *page_alloc(u64 len) LIKE_MALLOC; // Internal: allocates a multiple of CPU_PAGE_SIZE bytes with mmap
188 void *page_alloc_zero(u64 len) LIKE_MALLOC;
189 void page_free(void *start, u64 len);
190 void *page_realloc(void *start, u64 old_len, u64 new_len);
192 void *big_alloc(u64 len) LIKE_MALLOC; /** Allocate a large memory block in the most efficient way available. **/
193 void *big_alloc_zero(u64 len) LIKE_MALLOC; /** Allocate and clear a large memory block. **/
194 void big_free(void *start, u64 len); /** Free block allocated by @big_alloc() or @big_alloc_zero(). **/
196 /*** === Random numbers (random.c) ***/
198 uns random_u32(void); /** Return a pseudorandom 32-bit number. **/
199 uns random_max(uns max); /** Return a pseudorandom 32-bit number in range [0,@max). **/
200 u64 random_u64(void); /** Return a pseudorandom 64-bit number. **/
201 u64 random_max_u64(u64 max); /** Return a pseudorandom 64-bit number in range [0,@max). **/