libdarwin/h/string.h

   1 /*
   2  * Copyright (c) 2018 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*!
  25  * @header
  26  * Non-standard, Darwin-specific additions to the string(3) family of APIs.
  27  */
  28 #ifndef __DARWIN_STRING_H
  29 #define __DARWIN_STRING_H
  30
  31 #include <os/base.h>
  32 #include <os/api.h>
  33 #include <sys/cdefs.h>
  34
  35 __BEGIN_DECLS;
  36
  37 /*!
  38  * @typedef os_flag_t
  39  * A type describing a flag's human-readable name.
  40  *
  41  * @property ohf_flag
  42  * The flag value.
  43  *
  44  * @property ohf_human
  45  * The human-readable, string representation of the flag value.
  46  */
  47 DARWIN_API_AVAILABLE_20170407
  48 typedef struct _os_flag {
  49         const uint64_t ohf_flag;
  50         const char *const ohf_human_flag;
  51 } os_flag_t;
  52
  53 /*!
  54  * @define OS_FLAGSET_COUNT
  55  * The maximum number of flags that a flagset can represent.
  56  */
  57 #define OS_FLAGSET_COUNT (sizeof(uint64_t) * BYTE_SIZE)
  58
  59 /*!
  60  * @typedef os_flagset_t
  61  * A type describing an array of human flags. Can accommodate up to 64 flags.
  62  */
  63 DARWIN_API_AVAILABLE_20170407
  64 typedef os_flag_t os_flagset_t[OS_FLAGSET_COUNT];
  65
  66 /*!
  67  * @macro os_flag_init
  68  * Initializer for a {@link os_flag_t} structure which stringifies the
  69  * flag value.
  70  *
  71  * @param __flag
  72  * The name of the flag to initialize.
  73  */
  74 #define os_flag_init(__flag) { \
  75         .ohf_flag = __flag, \
  76         .ohf_human_flag = #__flag, \
  77 }
  78
  79 /*!
  80  * @function strerror_np
  81  * Returns a human-readable string for the given {@link errno_t} or
  82  * POSIX error code.
  83  *
  84  * @param code
  85  * The error code for which to obtain the string.
  86  *
  87  * @result
  88  * A human-readable string describing the error condition. If a POSIX error code
  89  * is given, this is equivalent to a call to strerror(3).
  90  */
  91 DARWIN_API_AVAILABLE_20170407
  92 OS_EXPORT OS_WARN_RESULT OS_PURE
  93 const char *
  94 strerror_np(int code);
  95
  96 /*!
  97  * @function symerror_np
  98  * Returns the token name of the given {@link errno_t} or POSIX error
  99  * code.
 100  *
 101  * @param code
 102  * The error code for which to obtain the token string.
 103  *
 104  * @result
 105  * The string describing the error token. For example, if code 2 is passed, the
 106  * string "EPERM" is returned.
 107  */
 108 DARWIN_API_AVAILABLE_20170407
 109 OS_EXPORT OS_WARN_RESULT OS_PURE
 110 const char *
 111 symerror_np(int code);
 112
 113 /*!
 114  * @function symexit_np
 115  * Returns the token name of the given sysexits(3) code.
 116  *
 117  * @param code
 118  * The sysexits(3) code for which to obtain the token string.
 119  *
 120  * @result
 121  * The string describing the exit code. For example, if 64 is passed, the string
 122  * "EX_USAGE" is returned. If the code is unrecognized, "EX_UNAVAILABLE" is
 123  * returned, which is more or less documented in sysexits(3) as the ¯\_(ツ)_/¯
 124  * exit code.
 125  */
 126 DARWIN_API_AVAILABLE_20170407
 127 OS_EXPORT OS_WARN_RESULT OS_PURE
 128 const char *
 129 symexit_np(int code);
 130
 131 /*!
 132  * @function os_flagset_copy_string
 133  * Returns a human-readable representation of the flags set for a given word.
 134  *
 135  * @param flagset
 136  * The human flagset which describes how to interpret the {@link flags}
 137  * parameter.
 138  *
 139  * @param flags
 140  * The flags to interpret.
 141  *
 142  * @result
 143  * The human-readable representation of all flags set in the {@link flags}
 144  * parameter, separated by the pipe character. The caller is responsible for
 145  * calling free(3) on this object when it is no longer needed.
 146  *
 147  * @discussion
 148  * This API is to be used in combination with {@link os_flag_init} to make
 149  * printing the contents of flags fields simple. For example, this code can
 150  * easily print a human-readable representation of the bits set in a Mach
 151  * message header:
 152  *
 153  *     static const os_flagset_t _mach_msgh_bits = {
 154  *          os_flag_init(MACH_MSGH_BITS_COMPLEX),
 155  *          os_flag_init(MACH_MSGH_BITS_RAISEIMP),
 156  *          os_flag_init(MACH_MSGH_BITS_IMPHOLDASRT),
 157  *    };
 158  *
 159  *    char *flags_string = os_flagset_copy_string(&_mach_msgh_bits,
 160  *            hdr->msgh_bits);
 161  *
 162  * For a message header with the MACH_MSGH_BITS_COMPLEX and
 163  * MACH_MSGH_BITS_RAISEIMP bits set, this will return the string
 164  *
 165  *     MACH_MSGH_BITS_COMPLEX|MACH_MSGH_BITS_RAISEIMP
 166  */
 167 DARWIN_API_AVAILABLE_20170407
 168 OS_EXPORT OS_WARN_RESULT OS_MALLOC
 169 char *
 170 os_flagset_copy_string(const os_flagset_t flagset, uint64_t flags);
 171
 172 __END_DECLS;
 173
 174 #endif // __DARWIN_STRING_H