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| 1 | +// Copyright 2024 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 | +package unix |
| 6 | + |
| 7 | +import ( |
| 8 | + "runtime" |
| 9 | + "sync" |
| 10 | + "syscall" |
| 11 | + "unsafe" |
| 12 | +) |
| 13 | + |
| 14 | +//go:linkname procUname libc_uname |
| 15 | + |
| 16 | +var procUname uintptr |
| 17 | + |
| 18 | +// utsname represents the fields of a struct utsname defined in <sys/utsname.h>. |
| 19 | +type utsname struct { |
| 20 | + Sysname [257]byte |
| 21 | + Nodename [257]byte |
| 22 | + Release [257]byte |
| 23 | + Version [257]byte |
| 24 | + Machine [257]byte |
| 25 | +} |
| 26 | + |
| 27 | +// KernelVersion returns major and minor kernel version numbers |
| 28 | +// parsed from the syscall.Uname's Version field, or (0, 0) if the |
| 29 | +// version can't be obtained or parsed. |
| 30 | +func KernelVersion() (major int, minor int) { |
| 31 | + var un utsname |
| 32 | + _, _, errno := rawSyscall6(uintptr(unsafe.Pointer(&procUname)), 1, uintptr(unsafe.Pointer(&un)), 0, 0, 0, 0, 0) |
| 33 | + if errno != 0 { |
| 34 | + return 0, 0 |
| 35 | + } |
| 36 | + |
| 37 | + // The version string is in the form "<version>.<update>.<sru>.<build>.<reserved>" |
| 38 | + // on Solaris: https://blogs.oracle.com/solaris/post/whats-in-a-uname- |
| 39 | + // Therefore, we use the Version field on Solaris when available. |
| 40 | + ver := un.Version[:] |
| 41 | + if runtime.GOOS == "illumos" { |
| 42 | + // Illumos distributions use different formats without a parsable |
| 43 | + // and unified pattern for the Version field while Release level |
| 44 | + // string is guaranteed to be in x.y or x.y.z format regardless of |
| 45 | + // whether the kernel is Solaris or illumos. |
| 46 | + ver = un.Release[:] |
| 47 | + } |
| 48 | + |
| 49 | + parseNext := func() (n int) { |
| 50 | + for i, c := range ver { |
| 51 | + if c == '.' { |
| 52 | + ver = ver[i+1:] |
| 53 | + return |
| 54 | + } |
| 55 | + if '0' <= c && c <= '9' { |
| 56 | + n = n*10 + int(c-'0') |
| 57 | + } |
| 58 | + } |
| 59 | + ver = nil |
| 60 | + return |
| 61 | + } |
| 62 | + |
| 63 | + major = parseNext() |
| 64 | + minor = parseNext() |
| 65 | + |
| 66 | + return |
| 67 | +} |
| 68 | + |
| 69 | +// SupportSockNonblockCloexec tests if SOCK_NONBLOCK and SOCK_CLOEXEC are supported |
| 70 | +// for socket() system call, returns true if affirmative. |
| 71 | +var SupportSockNonblockCloexec = sync.OnceValue(func() bool { |
| 72 | + // First test if socket() supports SOCK_NONBLOCK and SOCK_CLOEXEC directly. |
| 73 | + s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, 0) |
| 74 | + if err == nil { |
| 75 | + syscall.Close(s) |
| 76 | + return true |
| 77 | + } |
| 78 | + if err != syscall.EPROTONOSUPPORT && err != syscall.EINVAL { |
| 79 | + // Something wrong with socket(), fall back to checking the kernel version. |
| 80 | + major, minor := KernelVersion() |
| 81 | + if runtime.GOOS == "illumos" { |
| 82 | + return major > 5 || (major == 5 && minor >= 11) // minimal requirement is SunOS 5.11 |
| 83 | + } |
| 84 | + return major > 11 || (major == 11 && minor >= 4) |
| 85 | + } |
| 86 | + return false |
| 87 | +}) |
| 88 | + |
| 89 | +// SupportAccept4 tests whether accept4 system call is available. |
| 90 | +var SupportAccept4 = sync.OnceValue(func() bool { |
| 91 | + for { |
| 92 | + // Test if the accept4() is available. |
| 93 | + _, _, err := syscall.Accept4(0, syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC) |
| 94 | + if err == syscall.EINTR { |
| 95 | + continue |
| 96 | + } |
| 97 | + return err != syscall.ENOSYS |
| 98 | + } |
| 99 | +}) |
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