diff options
Diffstat (limited to 'vendor/golang.org/x/sys/unix/dev_linux.go')
| -rw-r--r-- | vendor/golang.org/x/sys/unix/dev_linux.go | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/vendor/golang.org/x/sys/unix/dev_linux.go b/vendor/golang.org/x/sys/unix/dev_linux.go new file mode 100644 index 0000000..d165d6f --- /dev/null +++ b/vendor/golang.org/x/sys/unix/dev_linux.go | |||
| @@ -0,0 +1,42 @@ | |||
| 1 | // Copyright 2017 The Go Authors. All rights reserved. | ||
| 2 | // Use of this source code is governed by a BSD-style | ||
| 3 | // license that can be found in the LICENSE file. | ||
| 4 | |||
| 5 | // Functions to access/create device major and minor numbers matching the | ||
| 6 | // encoding used by the Linux kernel and glibc. | ||
| 7 | // | ||
| 8 | // The information below is extracted and adapted from bits/sysmacros.h in the | ||
| 9 | // glibc sources: | ||
| 10 | // | ||
| 11 | // dev_t in glibc is 64-bit, with 32-bit major and minor numbers. glibc's | ||
| 12 | // default encoding is MMMM Mmmm mmmM MMmm, where M is a hex digit of the major | ||
| 13 | // number and m is a hex digit of the minor number. This is backward compatible | ||
| 14 | // with legacy systems where dev_t is 16 bits wide, encoded as MMmm. It is also | ||
| 15 | // backward compatible with the Linux kernel, which for some architectures uses | ||
| 16 | // 32-bit dev_t, encoded as mmmM MMmm. | ||
| 17 | |||
| 18 | package unix | ||
| 19 | |||
| 20 | // Major returns the major component of a Linux device number. | ||
| 21 | func Major(dev uint64) uint32 { | ||
| 22 | major := uint32((dev & 0x00000000000fff00) >> 8) | ||
| 23 | major |= uint32((dev & 0xfffff00000000000) >> 32) | ||
| 24 | return major | ||
| 25 | } | ||
| 26 | |||
| 27 | // Minor returns the minor component of a Linux device number. | ||
| 28 | func Minor(dev uint64) uint32 { | ||
| 29 | minor := uint32((dev & 0x00000000000000ff) >> 0) | ||
| 30 | minor |= uint32((dev & 0x00000ffffff00000) >> 12) | ||
| 31 | return minor | ||
| 32 | } | ||
| 33 | |||
| 34 | // Mkdev returns a Linux device number generated from the given major and minor | ||
| 35 | // components. | ||
| 36 | func Mkdev(major, minor uint32) uint64 { | ||
| 37 | dev := (uint64(major) & 0x00000fff) << 8 | ||
| 38 | dev |= (uint64(major) & 0xfffff000) << 32 | ||
| 39 | dev |= (uint64(minor) & 0x000000ff) << 0 | ||
| 40 | dev |= (uint64(minor) & 0xffffff00) << 12 | ||
| 41 | return dev | ||
| 42 | } | ||