| 1 | /* Definitions of macros to access `dev_t' values. |
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| 2 | Copyright (C) 1996-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #ifndef _BITS_SYSMACROS_H |
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| 20 | #define _BITS_SYSMACROS_H 1 |
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| 21 | |
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| 22 | #ifndef _SYS_SYSMACROS_H |
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| 23 | # error "Never include <bits/sysmacros.h> directly; use <sys/sysmacros.h> instead." |
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| 24 | #endif |
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| 25 | |
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| 26 | /* dev_t in glibc is a 64-bit quantity, with 32-bit major and minor numbers. |
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| 27 | Our default encoding is MMMM Mmmm mmmM MMmm, where M is a hex digit of |
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| 28 | the major number and m is a hex digit of the minor number. This is |
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| 29 | downward compatible with legacy systems where dev_t is 16 bits wide, |
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| 30 | encoded as MMmm. It is also downward compatible with the Linux kernel, |
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| 31 | which (as of 2016) uses 32-bit dev_t, encoded as mmmM MMmm. |
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| 32 | |
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| 33 | Systems that use an incompatible encoding for dev_t should override this |
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| 34 | file in the appropriate sysdeps subdirectory. */ |
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| 35 | |
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| 36 | #define __SYSMACROS_DECLARE_MAJOR(DECL_TEMPL) \ |
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| 37 | DECL_TEMPL(unsigned int, major, (__dev_t __dev)) |
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| 38 | |
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| 39 | #define __SYSMACROS_DEFINE_MAJOR(DECL_TEMPL) \ |
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| 40 | __SYSMACROS_DECLARE_MAJOR (DECL_TEMPL) \ |
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| 41 | { \ |
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| 42 | unsigned int __major; \ |
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| 43 | __major = ((__dev & (__dev_t) 0x00000000000fff00u) >> 8); \ |
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| 44 | __major |= ((__dev & (__dev_t) 0xfffff00000000000u) >> 32); \ |
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| 45 | return __major; \ |
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| 46 | } |
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| 47 | |
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| 48 | #define __SYSMACROS_DECLARE_MINOR(DECL_TEMPL) \ |
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| 49 | DECL_TEMPL(unsigned int, minor, (__dev_t __dev)) |
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| 50 | |
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| 51 | #define __SYSMACROS_DEFINE_MINOR(DECL_TEMPL) \ |
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| 52 | __SYSMACROS_DECLARE_MINOR (DECL_TEMPL) \ |
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| 53 | { \ |
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| 54 | unsigned int __minor; \ |
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| 55 | __minor = ((__dev & (__dev_t) 0x00000000000000ffu) >> 0); \ |
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| 56 | __minor |= ((__dev & (__dev_t) 0x00000ffffff00000u) >> 12); \ |
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| 57 | return __minor; \ |
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| 58 | } |
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| 59 | |
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| 60 | #define __SYSMACROS_DECLARE_MAKEDEV(DECL_TEMPL) \ |
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| 61 | DECL_TEMPL(__dev_t, makedev, (unsigned int __major, unsigned int __minor)) |
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| 62 | |
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| 63 | #define __SYSMACROS_DEFINE_MAKEDEV(DECL_TEMPL) \ |
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| 64 | __SYSMACROS_DECLARE_MAKEDEV (DECL_TEMPL) \ |
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| 65 | { \ |
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| 66 | __dev_t __dev; \ |
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| 67 | __dev = (((__dev_t) (__major & 0x00000fffu)) << 8); \ |
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| 68 | __dev |= (((__dev_t) (__major & 0xfffff000u)) << 32); \ |
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| 69 | __dev |= (((__dev_t) (__minor & 0x000000ffu)) << 0); \ |
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| 70 | __dev |= (((__dev_t) (__minor & 0xffffff00u)) << 12); \ |
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| 71 | return __dev; \ |
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| 72 | } |
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| 73 | |
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| 74 | #endif /* bits/sysmacros.h */ |
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| 75 | |
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