compat.h

   1 /*
   2  * Copyright (c) 2021-2022 Sergey Sushilin <sergeysushilin@protonmail.com>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifndef _COMPAT_H
  18 #define _COMPAT_H 1
  19
  20 #include <stdarg.h>
  21 #include <sys/types.h>
  22
  23 #include "attributes.h"
  24
  25 #if !defined(va_copy)
  26 # if defined(__va_copy)
  27 #  define va_copy(d, s) __va_copy(d, s)
  28 # else
  29 #  define va_copy(d, s) memcpy(&(d), &(s), sizeof(va_list))
  30 # endif
  31 #endif /* !defined(va_copy) */
  32
  33 #if !defined(GLOBAL_PATH)
  34 # define GLOBAL_PATH "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
  35 #endif
  36
  37 #if !defined(UID_MAX)
  38 # define UID_MAX 65535
  39 #endif /* UID_MAX */
  40 #if !defined(GID_MAX)
  41 # define GID_MAX 65535
  42 #endif /* GID_MAX */
  43
  44 #if !defined(ROOT_UID)
  45 # if defined(__TANDEM)
  46 #  define ROOT_UID 65535
  47 # else
  48 #  define ROOT_UID 0
  49 # endif
  50 #endif /* ROOT_UID */
  51
  52 #if !defined(PATH_MAX)
  53 # if defined(MAX_PATH)
  54 #  define PATH_MAX MAX_PATH
  55 # elif defined(MAXPATHLEN)
  56 #  define PATH_MAX MAXPATHLEN
  57 # else
  58 #  define PATH_MAX 4096
  59 # endif
  60 #endif /* PATH_MAX */
  61
  62 #if !defined(NGROUPS_MAX)
  63 # define NGROUPS_MAX 65535
  64 #endif /* NGROUPS_MAX */
  65
  66 #if !defined(LINE_MAX)
  67 # define LINE_MAX 4096
  68 #endif /* LINE_MAX */
  69
  70 #if !defined(_PW_NAME_LEN)
  71 # define _PW_NAME_LEN 32
  72 #endif /* _PW_NAME_LEN */
  73
  74 #if !defined(SAFE_PATH)
  75 # define SAFE_PATH "/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin"
  76 #endif /* SAFE_PATH */
  77
  78 #if __STDC_VERSION__ >= 199901L
  79 # include <stdbool.h>
  80 #else
  81 # undef _Bool
  82 # undef bool
  83 # undef true
  84 # undef false
  85 /* For the sake of symbolic names in gdb, define true and false as
  86    enum constants, not only as macros.
  87    It is tempting to write
  88    typedef enum { false = 0, true = 1 } _Bool;
  89    so that gdb prints values of type 'bool' symbolically.  */
  90 typedef enum { _False = 0, _True = 1 } __bool;
  91 # define _Bool __bool
  92 # define bool  _Bool
  93 # define true  _True
  94 # define false _False
  95 #endif /* __STDC_VERSION__ >= 199901L */
  96
  97 #if __STDC_VERSION__ < 199901L
  98 # if __GNUC__ >= 2 || defined(__clang__) || defined(__TINYC__) || defined(__PCC__)
  99 #  define inline __inline__
 100 # else
 101 #  define inline /* Nothing.  */
 102 # endif
 103 #endif
 104
 105 /*
 106  * GCC 2.95 provides `__restrict' as an extension to C90 to support the
 107  * C99-specific `restrict' type qualifier.  We happen to use `__restrict' as
 108  * a way to define the `restrict' type qualifier without disturbing older
 109  * software that is unaware of C99 keywords.
 110  */
 111 #if __STDC_VERSION__ < 199901L
 112 # if __GNUC__ >= 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95)
 113 #  define restrict __restrict
 114 # else
 115 #  define restrict /* Nothing.  */
 116 # endif
 117 #endif
 118
 119 #if !defined(HOST_NAME_MAX)
 120 # if defined(_POSIX_HOST_NAME_MAX)
 121 #  define HOST_NAME_MAX _POSIX_HOST_NAME_MAX
 122 # else
 123 #  define HOST_NAME_MAX 512
 124 # endif
 125 #endif
 126
 127 extern size_t full_read(int fd, void *buf, size_t len)
 128         __nonnull((2)) __warn_unused_result;
 129 extern size_t full_write(int fd, void const *buf, size_t len)
 130         __nonnull((2)) __warn_unused_result;
 131
 132 #if !defined(__NetBSD__)
 133 extern void closefrom(int lowfd);
 134 #endif
 135
 136 #if !defined(_GNU_SOURCE)
 137 extern int execvpe(char const *restrict file,
 138                    char *const *restrict argv,
 139                    char *const *restrict envp);
 140 #endif
 141
 142 extern char const *__progname;
 143
 144 extern void setprogname(char const *progname) __nonnull((1));
 145 extern char const *getprogname(void) __warn_unused_result;
 146
 147 #if !defined(__NetBSD__)
 148 extern void *reallocarray(void *pointer, size_t count, size_t size);
 149 #endif
 150
 151 extern int setresuid(uid_t ruid, uid_t euid, uid_t suid);
 152 extern int setresuid(gid_t rgid, gid_t egid, gid_t sgid);
 153
 154 extern size_t strlcpy(char *restrict dst, char const *restrict src, size_t dsize) __nonnull((1, 2));
 155 extern size_t strlcat(char *restrict dst, char const *restrict src, size_t dsize) __nonnull((1, 2));
 156
 157 #if !defined(__FreeBSD__)
 158 extern long long int strtonum(char const *restrict numstr,
 159                               long long int minval, long long int maxval,
 160                               char const *restrict *restrict errstrp)
 161         __nonnull((1)) __warn_unused_result;
 162 #endif
 163 extern unsigned long long int strtounum(char const *restrict numstr,
 164                                         unsigned long long int maxval,
 165                                         char const *restrict *restrict errstrp)
 166         __nonnull((1)) __warn_unused_result;
 167
 168 extern void vwarnc(int code, char const *fmt, va_list ap) __format_printf(2, 0);
 169 extern void warnc(int code, char const *fmt, ...) __format_printf(2, 3);
 170
 171 extern void verrc(int eval, int code, char const *fmt, va_list ap) __format_printf(3, 0) __noreturn;
 172 extern void errc(int eval, int code, char const *fmt, ...) __format_printf(3, 4) __noreturn;
 173
 174 extern char *strchrnul(char const *string, int character) __pure __nonnull((1)) __warn_unused_result;
 175
 176 #if (!defined(__GNUC__) || __GNUC__ < 5) \
 177   && (!defined(__clang_major__) \
 178    || (__clang_major__ < 3 || __clang_major__ == 3 && __clang_minor__ < 8)) \
 179   || defined(__ICC)
 180 #include <limits.h>
 181 /* https://stackoverflow.com/a/1815371 */
 182 static inline __nonnull((3)) __warn_unused_result __const bool __builtin_mul_overflow(size_t a, size_t b, size_t *c)
 183 {
 184 # define HALF_SIZE_BIT  (sizeof(size_t) * CHAR_BIT / 2)
 185 # define HI(x)          (x >> HALF_SIZE_BIT)
 186 # define LO(x)          (x & ((1 << HALF_SIZE_BIT) - 1))
 187         size_t s0, s1, s2, s3, x, result, carry;
 188
 189         x = LO(a) * LO(b);
 190         s0 = LO(x);
 191
 192         x = HI(a) * LO(b) + HI(x);
 193         s1 = LO(x);
 194         s2 = HI(x);
 195
 196         x = s1 + LO(a) * HI(b);
 197         s1 = LO(x);
 198
 199         x = s2 + HI(a) * HI(b) + HI(x);
 200         s2 = LO(x);
 201         s3 = HI(x);
 202
 203         result = (s1 << HALF_SIZE_BIT) | s0;
 204         carry = (s3 << HALF_SIZE_BIT) | s2;
 205
 206         *c = result;
 207         return (carry != 0);
 208 }
 209 #endif
 210
 211 #define BARF_IF_FAIL(e) (sizeof(char [1 - 2 * ((e) ? 0 : 1)]) - 1)
 212
 213 #if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1)) \
 214         || defined(__clang__) || defined(__PCC__) || defined(__TINYC__)
 215 # define is_same_type(a, b) __builtin_types_compatible_p(__typeof__(a), \
 216                                                          __typeof__(b))
 217 #else
 218 # define is_same_type(a, b) 0 /* (sizeof(a) == sizeof(b)) */
 219 #endif
 220
 221 #define countof(a) \
 222         (sizeof(a) / sizeof((a)[0]) \
 223          + BARF_IF_FAIL(!is_same_type((a), &(a)[0])))
 224 #define endof(a) \
 225         (&(a)[countof(a)])
 226
 227 #endif /* _COMPAT_H */