libblkid-tiny/c.h

   1 /*
   2  * Fundamental C definitions.
   3  */
   4
   5 #ifndef UTIL_LINUX_C_H
   6 #define UTIL_LINUX_C_H
   7
   8 #include <limits.h>
   9 #include <stddef.h>
  10 #include <stdint.h>
  11 #include <stdio.h>
  12 #include <unistd.h>
  13 #include <stdarg.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <errno.h>
  17
  18 #include <assert.h>
  19
  20 #ifdef HAVE_ERR_H
  21 # include <err.h>
  22 #endif
  23
  24 /*
  25  * Compiler-specific stuff
  26  */
  27 #ifndef __GNUC_PREREQ
  28 # if defined __GNUC__ && defined __GNUC_MINOR__
  29 #  define __GNUC_PREREQ(maj, min) \
  30         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
  31 # else
  32 #  define __GNUC_PREREQ(maj, min) 0
  33 # endif
  34 #endif
  35
  36 #ifdef __GNUC__
  37
  38 /* &a[0] degrades to a pointer: a different type from an array */
  39 # define __must_be_array(a) \
  40         UL_BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(__typeof__(a), __typeof__(&a[0])))
  41
  42 # define ignore_result(x) __extension__ ({ \
  43         __typeof__(x) __dummy __attribute__((__unused__)) = (x); (void) __dummy; \
  44 })
  45
  46 #else /* !__GNUC__ */
  47 # define __must_be_array(a)     0
  48 # define __attribute__(_arg_)
  49 # define ignore_result(x) ((void) (x))
  50 #endif /* !__GNUC__ */
  51
  52 /*
  53  * Function attributes
  54  */
  55 #ifndef __ul_alloc_size
  56 # if __GNUC_PREREQ (4, 3)
  57 #  define __ul_alloc_size(s) __attribute__((alloc_size(s), warn_unused_result))
  58 # else
  59 #  define __ul_alloc_size(s)
  60 # endif
  61 #endif
  62
  63 #ifndef __ul_calloc_size
  64 # if __GNUC_PREREQ (4, 3)
  65 #  define __ul_calloc_size(n, s) __attribute__((alloc_size(n, s), warn_unused_result))
  66 # else
  67 #  define __ul_calloc_size(n, s)
  68 # endif
  69 #endif
  70
  71 /*
  72  * Force a compilation error if condition is true, but also produce a
  73  * result (of value 0 and type size_t), so the expression can be used
  74  * e.g. in a structure initializer (or wherever else comma expressions
  75  * aren't permitted).
  76  */
  77 #define UL_BUILD_BUG_ON_ZERO(e) __extension__ (sizeof(struct { int:-!!(e); }))
  78 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
  79
  80 #ifndef ARRAY_SIZE
  81 # define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  82 #endif
  83
  84 #ifndef PATH_MAX
  85 # define PATH_MAX 4096
  86 #endif
  87
  88 #ifndef TRUE
  89 # define TRUE 1
  90 #endif
  91
  92 #ifndef FALSE
  93 # define FALSE 0
  94 #endif
  95
  96 #ifndef min
  97 # define min(x, y) __extension__ ({             \
  98         __typeof__(x) _min1 = (x);              \
  99         __typeof__(y) _min2 = (y);              \
 100         (void) (&_min1 == &_min2);              \
 101         _min1 < _min2 ? _min1 : _min2; })
 102 #endif
 103
 104 #ifndef max
 105 # define max(x, y) __extension__ ({             \
 106         __typeof__(x) _max1 = (x);              \
 107         __typeof__(y) _max2 = (y);              \
 108         (void) (&_max1 == &_max2);              \
 109         _max1 > _max2 ? _max1 : _max2; })
 110 #endif
 111
 112 #ifndef cmp_numbers
 113 # define cmp_numbers(x, y) __extension__ ({     \
 114         __typeof__(x) _a = (x);                 \
 115         __typeof__(y) _b = (y);                 \
 116         (void) (&_a == &_b);                    \
 117         _a == _b ? 0 : _a > _b ? 1 : -1; })
 118 #endif
 119
 120 #ifndef offsetof
 121 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 122 #endif
 123
 124 #ifndef container_of
 125 #define container_of(ptr, type, member) __extension__ ({         \
 126         const __typeof__( ((type *)0)->member ) *__mptr = (ptr); \
 127         (type *)( (char *)__mptr - offsetof(type,member) );})
 128 #endif
 129
 130 #ifndef HAVE_PROGRAM_INVOCATION_SHORT_NAME
 131 # ifdef HAVE___PROGNAME
 132 extern char *__progname;
 133 #  define program_invocation_short_name __progname
 134 # else
 135 #  ifdef HAVE_GETEXECNAME
 136 #   define program_invocation_short_name \
 137                 prog_inv_sh_nm_from_file(getexecname(), 0)
 138 #  else
 139 #   define program_invocation_short_name \
 140                 prog_inv_sh_nm_from_file(__FILE__, 1)
 141 #  endif
 142 static char prog_inv_sh_nm_buf[256];
 143 static inline char *
 144 prog_inv_sh_nm_from_file(char *f, char stripext)
 145 {
 146         char *t;
 147
 148         if ((t = strrchr(f, '/')) != NULL)
 149                 t++;
 150         else
 151                 t = f;
 152
 153         strncpy(prog_inv_sh_nm_buf, t, sizeof(prog_inv_sh_nm_buf) - 1);
 154         prog_inv_sh_nm_buf[sizeof(prog_inv_sh_nm_buf) - 1] = '\0';
 155
 156         if (stripext && (t = strrchr(prog_inv_sh_nm_buf, '.')) != NULL)
 157                 *t = '\0';
 158
 159         return prog_inv_sh_nm_buf;
 160 }
 161 # endif
 162 #endif
 163
 164
 165 #ifndef HAVE_ERR_H
 166 static inline void
 167 errmsg(char doexit, int excode, char adderr, const char *fmt, ...)
 168 {
 169         fprintf(stderr, "%s: ", program_invocation_short_name);
 170         if (fmt != NULL) {
 171                 va_list argp;
 172                 va_start(argp, fmt);
 173                 vfprintf(stderr, fmt, argp);
 174                 va_end(argp);
 175                 if (adderr)
 176                         fprintf(stderr, ": ");
 177         }
 178         if (adderr)
 179                 fprintf(stderr, "%m");
 180         fprintf(stderr, "\n");
 181         if (doexit)
 182                 exit(excode);
 183 }
 184
 185 #ifndef HAVE_ERR
 186 # define err(E, FMT...) errmsg(1, E, 1, FMT)
 187 #endif
 188
 189 #ifndef HAVE_ERRX
 190 # define errx(E, FMT...) errmsg(1, E, 0, FMT)
 191 #endif
 192
 193 #ifndef HAVE_WARN
 194 # define warn(FMT...) errmsg(0, 0, 1, FMT)
 195 #endif
 196
 197 #ifndef HAVE_WARNX
 198 # define warnx(FMT...) errmsg(0, 0, 0, FMT)
 199 #endif
 200 #endif /* !HAVE_ERR_H */
 201
 202
 203 static inline __attribute__((const)) int is_power_of_2(unsigned long num)
 204 {
 205         return (num != 0 && ((num & (num - 1)) == 0));
 206 }
 207
 208 #ifndef HAVE_LOFF_T
 209 typedef int64_t loff_t;
 210 #endif
 211
 212 #if !defined(HAVE_DIRFD) && (!defined(HAVE_DECL_DIRFD) || HAVE_DECL_DIRFD == 0) && defined(HAVE_DIR_DD_FD)
 213 #include <sys/types.h>
 214 #include <dirent.h>
 215 static inline int dirfd(DIR *d)
 216 {
 217         return d->dd_fd;
 218 }
 219 #endif
 220
 221 /*
 222  * Fallback defines for old versions of glibc
 223  */
 224 #include <fcntl.h>
 225
 226 #ifdef O_CLOEXEC
 227 #define UL_CLOEXECSTR   "e"
 228 #else
 229 #define UL_CLOEXECSTR   ""
 230 #endif
 231
 232 #ifndef O_CLOEXEC
 233 #define O_CLOEXEC 0
 234 #endif
 235
 236 #ifdef __FreeBSD_kernel__
 237 #ifndef F_DUPFD_CLOEXEC
 238 #define F_DUPFD_CLOEXEC 17      /* Like F_DUPFD, but FD_CLOEXEC is set */
 239 #endif
 240 #endif
 241
 242
 243 #ifndef AI_ADDRCONFIG
 244 #define AI_ADDRCONFIG 0x0020
 245 #endif
 246
 247 #ifndef IUTF8
 248 #define IUTF8 0040000
 249 #endif
 250
 251 #if 0
 252 /*
 253  * MAXHOSTNAMELEN replacement
 254  */
 255 static inline size_t get_hostname_max(void)
 256 {
 257         long len = sysconf(_SC_HOST_NAME_MAX);
 258
 259         if (0 < len)
 260                 return len;
 261
 262 #ifdef MAXHOSTNAMELEN
 263         return MAXHOSTNAMELEN;
 264 #elif HOST_NAME_MAX
 265         return HOST_NAME_MAX;
 266 #endif
 267         return 64;
 268 }
 269
 270 /*
 271  * The usleep function was marked obsolete in POSIX.1-2001 and was removed
 272  * in POSIX.1-2008.  It was replaced with nanosleep() that provides more
 273  * advantages (like no interaction with signals and other timer functions).
 274  */
 275 #include <time.h>
 276
 277 static inline int xusleep(useconds_t usec)
 278 {
 279 #ifdef HAVE_NANOSLEEP
 280         struct timespec waittime = {
 281                 .tv_sec   =  usec / 1000000L,
 282                 .tv_nsec  = (usec % 1000000L) * 1000
 283         };
 284         return nanosleep(&waittime, NULL);
 285 #elif defined(HAVE_USLEEP)
 286         return usleep(usec);
 287 #else
 288 # error "System with usleep() or nanosleep() required!"
 289 #endif
 290 }
 291 #endif
 292
 293 /*
 294  * Constant strings for usage() functions. For more info see
 295  * Documentation/howto-usage-function.txt and disk-utils/delpart.c
 296  */
 297 #define USAGE_HEADER     _("\nUsage:\n")
 298 #define USAGE_OPTIONS    _("\nOptions:\n")
 299 #define USAGE_SEPARATOR    "\n"
 300 #define USAGE_HELP       _(" -h, --help     display this help and exit\n")
 301 #define USAGE_VERSION    _(" -V, --version  output version information and exit\n")
 302 #define USAGE_MAN_TAIL(_man)   _("\nFor more details see %s.\n"), _man
 303
 304 #define UTIL_LINUX_VERSION _("%s from %s\n"), program_invocation_short_name, PACKAGE_STRING
 305
 306 /*
 307  * scanf modifiers for "strings allocation"
 308  */
 309 #ifdef HAVE_SCANF_MS_MODIFIER
 310 #define UL_SCNsA        "%ms"
 311 #elif defined(HAVE_SCANF_AS_MODIFIER)
 312 #define UL_SCNsA        "%as"
 313 #endif
 314
 315 /*
 316  * seek stuff
 317  */
 318 #ifndef SEEK_DATA
 319 # define SEEK_DATA      3
 320 #endif
 321 #ifndef SEEK_HOLE
 322 # define SEEK_HOLE      4
 323 #endif
 324
 325
 326 /*
 327  * Macros to convert #define'itions to strings, for example
 328  * #define XYXXY 42
 329  * printf ("%s=%s\n", stringify(XYXXY), stringify_value(XYXXY));
 330  */
 331 #define stringify_value(s) stringify(s)
 332 #define stringify(s) #s
 333
 334 /*
 335  * UL_ASAN_BLACKLIST is a macro to tell AddressSanitizer (a compile-time
 336  * instrumentation shipped with Clang and GCC) to not instrument the
 337  * annotated function.  Furthermore, it will prevent the compiler from
 338  * inlining the function because inlining currently breaks the blacklisting
 339  * mechanism of AddressSanitizer.
 340  */
 341 #if defined(__has_feature)
 342 # if __has_feature(address_sanitizer)
 343 #  define UL_ASAN_BLACKLIST __attribute__((noinline)) __attribute__((no_sanitize_memory)) __attribute__((no_sanitize_address))
 344 # else
 345 #  define UL_ASAN_BLACKLIST     /* nothing */
 346 # endif
 347 #else
 348 # define UL_ASAN_BLACKLIST      /* nothing */
 349 #endif
 350
 351 #endif /* UTIL_LINUX_C_H */