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 <stdarg.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <errno.h>
  16
  17 #ifdef HAVE_ERR_H
  18 # include <err.h>
  19 #endif
  20
  21 /*
  22  * Compiler specific stuff
  23  */
  24 #ifndef __GNUC_PREREQ
  25 # if defined __GNUC__ && defined __GNUC_MINOR__
  26 #  define __GNUC_PREREQ(maj, min) \
  27         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
  28 # else
  29 #  define __GNUC_PREREQ(maj, min) 0
  30 # endif
  31 #endif
  32
  33 #ifdef __GNUC__
  34
  35 /* &a[0] degrades to a pointer: a different type from an array */
  36 # define __must_be_array(a) \
  37         UL_BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(__typeof__(a), __typeof__(&a[0])))
  38
  39 # define ignore_result(x) ({ \
  40         __typeof__(x) __dummy __attribute__((__unused__)) = (x); (void) __dummy; \
  41 })
  42
  43 #else /* !__GNUC__ */
  44 # define __must_be_array(a)     0
  45 # define __attribute__(_arg_)
  46 # define ignore_result(x) ((void) (x))
  47 #endif /* !__GNUC__ */
  48
  49 /*
  50  * Function attributes
  51  */
  52 #ifndef __ul_alloc_size
  53 # if __GNUC_PREREQ (4, 3)
  54 #  define __ul_alloc_size(s) __attribute__((alloc_size(s)))
  55 # else
  56 #  define __ul_alloc_size(s)
  57 # endif
  58 #endif
  59
  60 #ifndef __ul_calloc_size
  61 # if __GNUC_PREREQ (4, 3)
  62 #  define __ul_calloc_size(n, s) __attribute__((alloc_size(n, s)))
  63 # else
  64 #  define __ul_calloc_size(n, s)
  65 # endif
  66 #endif
  67
  68 /* Force a compilation error if condition is true, but also produce a
  69  * result (of value 0 and type size_t), so the expression can be used
  70  * e.g. in a structure initializer (or where-ever else comma expressions
  71  * aren't permitted).
  72  */
  73 #define UL_BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
  74 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
  75
  76 #ifndef ARRAY_SIZE
  77 # define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  78 #endif
  79
  80 #ifndef PATH_MAX
  81 # define PATH_MAX 4096
  82 #endif
  83
  84 #ifndef TRUE
  85 # define TRUE 1
  86 #endif
  87
  88 #ifndef FALSE
  89 # define FALSE 0
  90 #endif
  91
  92 #ifndef min
  93 # define min(x, y) ({                           \
  94         __typeof__(x) _min1 = (x);              \
  95         __typeof__(y) _min2 = (y);              \
  96         (void) (&_min1 == &_min2);              \
  97         _min1 < _min2 ? _min1 : _min2; })
  98 #endif
  99
 100 #ifndef max
 101 # define max(x, y) ({                           \
 102         __typeof__(x) _max1 = (x);              \
 103         __typeof__(y) _max2 = (y);              \
 104         (void) (&_max1 == &_max2);              \
 105         _max1 > _max2 ? _max1 : _max2; })
 106 #endif
 107
 108 #ifndef offsetof
 109 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 110 #endif
 111
 112 #ifndef container_of
 113 #define container_of(ptr, type, member) ({                       \
 114         const __typeof__( ((type *)0)->member ) *__mptr = (ptr); \
 115         (type *)( (char *)__mptr - offsetof(type,member) );})
 116 #endif
 117
 118 #ifndef HAVE_PROGRAM_INVOCATION_SHORT_NAME
 119 # ifdef HAVE___PROGNAME
 120 extern char *__progname;
 121 #  define program_invocation_short_name __progname
 122 # else
 123 #  ifdef HAVE_GETEXECNAME
 124 #   define program_invocation_short_name \
 125                 prog_inv_sh_nm_from_file(getexecname(), 0)
 126 #  else
 127 #   define program_invocation_short_name \
 128                 prog_inv_sh_nm_from_file(__FILE__, 1)
 129 #  endif
 130 static char prog_inv_sh_nm_buf[256];
 131 static inline char *
 132 prog_inv_sh_nm_from_file(char *f, char stripext)
 133 {
 134         char *t;
 135
 136         if ((t = strrchr(f, '/')) != NULL)
 137                 t++;
 138         else
 139                 t = f;
 140
 141         strncpy(prog_inv_sh_nm_buf, t, sizeof(prog_inv_sh_nm_buf) - 1);
 142         prog_inv_sh_nm_buf[sizeof(prog_inv_sh_nm_buf) - 1] = '\0';
 143
 144         if (stripext && (t = strrchr(prog_inv_sh_nm_buf, '.')) != NULL)
 145                 *t = '\0';
 146
 147         return prog_inv_sh_nm_buf;
 148 }
 149 # endif
 150 #endif
 151
 152
 153 #ifndef HAVE_ERR_H
 154 static inline void
 155 errmsg(char doexit, int excode, char adderr, const char *fmt, ...)
 156 {
 157         fprintf(stderr, "%s: ", program_invocation_short_name);
 158         if (fmt != NULL) {
 159                 va_list argp;
 160                 va_start(argp, fmt);
 161                 vfprintf(stderr, fmt, argp);
 162                 va_end(argp);
 163                 if (adderr)
 164                         fprintf(stderr, ": ");
 165         }
 166         if (adderr)
 167                 fprintf(stderr, "%m");
 168         fprintf(stderr, "\n");
 169         if (doexit)
 170                 exit(excode);
 171 }
 172
 173 #ifndef HAVE_ERR
 174 # define err(E, FMT...) errmsg(1, E, 1, FMT)
 175 #endif
 176
 177 #ifndef HAVE_ERRX
 178 # define errx(E, FMT...) errmsg(1, E, 0, FMT)
 179 #endif
 180
 181 #ifndef HAVE_WARN
 182 # define warn(FMT...) errmsg(0, 0, 1, FMT)
 183 #endif
 184
 185 #ifndef HAVE_WARNX
 186 # define warnx(FMT...) errmsg(0, 0, 0, FMT)
 187 #endif
 188 #endif /* !HAVE_ERR_H */
 189
 190
 191 static inline __attribute__((const)) int is_power_of_2(unsigned long num)
 192 {
 193         return (num != 0 && ((num & (num - 1)) == 0));
 194 }
 195
 196 #ifndef HAVE_LOFF_T
 197 typedef int64_t loff_t;
 198 #endif
 199
 200 #if !defined(HAVE_DIRFD) && (!defined(HAVE_DECL_DIRFD) || HAVE_DECL_DIRFD == 0) && defined(HAVE_DIR_DD_FD)
 201 #include <sys/types.h>
 202 #include <dirent.h>
 203 static inline int dirfd(DIR *d)
 204 {
 205         return d->dd_fd;
 206 }
 207 #endif
 208
 209 /*
 210  * Fallback defines for old versions of glibc
 211  */
 212 #include <fcntl.h>
 213 #ifndef O_CLOEXEC
 214 #define O_CLOEXEC 0
 215 #endif
 216
 217 #ifndef AI_ADDRCONFIG
 218 #define AI_ADDRCONFIG 0x0020
 219 #endif
 220
 221 #ifndef IUTF8
 222 #define IUTF8 0040000
 223 #endif
 224
 225 /*
 226  * Constant strings for usage() functions. For more info see
 227  * Documentation/howto-usage-function.txt and sys-utils/arch.c
 228  */
 229 #define USAGE_HEADER     _("\nUsage:\n")
 230 #define USAGE_OPTIONS    _("\nOptions:\n")
 231 #define USAGE_SEPARATOR  _("\n")
 232 #define USAGE_HELP       _(" -h, --help     display this help and exit\n")
 233 #define USAGE_VERSION    _(" -V, --version  output version information and exit\n")
 234 #define USAGE_MAN_TAIL(_man)   _("\nFor more details see %s.\n"), _man
 235
 236 #define UTIL_LINUX_VERSION _("%s from %s\n"), program_invocation_short_name, PACKAGE_STRING
 237
 238 /*
 239  * scanf modifiers for "strings allocation"
 240  */
 241 #ifdef HAVE_SCANF_MS_MODIFIER
 242 #define UL_SCNsA        "%ms"
 243 #elif defined(HAVE_SCANF_AS_MODIFIER)
 244 #define UL_SCNsA        "%as"
 245 #endif
 246
 247 #endif /* UTIL_LINUX_C_H */