libgo/go/syscall/libcall_bsd.go

   1 // Copyright 2020 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 //go:build darwin || dragonfly || freebsd || netbsd || openbsd
   6 // +build darwin dragonfly freebsd netbsd openbsd
   7
   8 // BSD library calls.
   9
  10 package syscall
  11
  12 import (
  13         "unsafe"
  14 )
  15
  16 //sys   sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error)
  17 //sysctl(mib *_C_int, miblen uintptr, old *byte, oldlen *uintptr, new *byte, newlen uintptr) _C_int
  18
  19 //sysnb raw_ptrace(request int, pid int, addr uintptr, data uintptr) (err Errno)
  20 //ptrace(request _C_int, pid Pid_t, addr *byte, data _C_int) _C_int
  21
  22 //sys   paccept(fd int, rsa *RawSockaddrAny, addrlen *Socklen_t, sigmask *_sigset_t, flags int) (nfd int, err error)
  23 //paccept(s _C_int, rsa *RawSockaddrAny, addrlen *Socklen_t, sigmask *_sigset_t, flags int) _C_int
  24
  25 //sys   Flock(fd int, how int) (err error)
  26 //flock(fd _C_int, how _C_int) _C_int
  27
  28 func ReadDirent(fd int, buf []byte) (n int, err error) {
  29         // Final argument is (basep *uintptr) and the syscall doesn't take nil.
  30         // 64 bits should be enough. (32 bits isn't even on 386). Since the
  31         // actual system call is getdirentries64, 64 is a good guess.
  32         // TODO(rsc): Can we use a single global basep for all calls?
  33         var base = (*uintptr)(unsafe.Pointer(new(uint64)))
  34         return Getdirentries(fd, buf, base)
  35 }
  36
  37 func Accept4(fd, flags int) (nfd int, sa Sockaddr, err error) {
  38         var rsa RawSockaddrAny
  39         var len Socklen_t = SizeofSockaddrAny
  40         nfd, err = paccept(fd, &rsa, &len, nil, flags)
  41         if err != nil {
  42                 return
  43         }
  44         if len > SizeofSockaddrAny {
  45                 panic("RawSockaddrAny too small")
  46         }
  47         sa, err = anyToSockaddr(&rsa)
  48         if err != nil {
  49                 Close(nfd)
  50                 nfd = 0
  51         }
  52         return
  53 }
  54
  55 //sysnb pipe2(p *[2]_C_int, flags int) (err error)
  56 //pipe2(p *[2]_C_int, flags _C_int) _C_int
  57
  58 func Pipe2(p []int, flags int) (err error) {
  59         if len(p) != 2 {
  60                 return EINVAL
  61         }
  62         var pp [2]_C_int
  63         err = pipe2(&pp, flags)
  64         p[0] = int(pp[0])
  65         p[1] = int(pp[1])
  66         return
  67 }
  68
  69 func Sysctl(name string) (value string, err error) {
  70         // Translate name to mib number.
  71         mib, err := nametomib(name)
  72         if err != nil {
  73                 return "", err
  74         }
  75
  76         // Find size.
  77         n := uintptr(0)
  78         if err = sysctl(mib, nil, &n, nil, 0); err != nil {
  79                 return "", err
  80         }
  81         if n == 0 {
  82                 return "", nil
  83         }
  84
  85         // Read into buffer of that size.
  86         buf := make([]byte, n)
  87         if err = sysctl(mib, &buf[0], &n, nil, 0); err != nil {
  88                 return "", err
  89         }
  90
  91         // Throw away terminating NUL.
  92         if n > 0 && buf[n-1] == '\x00' {
  93                 n--
  94         }
  95         return string(buf[0:n]), nil
  96 }
  97
  98 func SysctlUint32(name string) (value uint32, err error) {
  99         // Translate name to mib number.
 100         mib, err := nametomib(name)
 101         if err != nil {
 102                 return 0, err
 103         }
 104
 105         // Read into buffer of that size.
 106         n := uintptr(4)
 107         buf := make([]byte, 4)
 108         if err = sysctl(mib, &buf[0], &n, nil, 0); err != nil {
 109                 return 0, err
 110         }
 111         if n != 4 {
 112                 return 0, EIO
 113         }
 114         return *(*uint32)(unsafe.Pointer(&buf[0])), nil
 115 }