golang syscall_darwin.1_13 代码
文件路径：/src/cmd/vendor/golang.org/x/sys/unix/syscall_darwin.1_13.go
/ Copyright 2019 The Go Authors. All rights reserved.
/ Use of this source code is governed by a BSD-style
/ license that can be found in the LICENSE file.
/go:build darwin && go1.13
/ +build darwin,go1.13
package unix
import (
"unsafe"
"golang.org/x/sys/internal/unsafeheader"
)
/sys closedir(dir uintptr) (err error)
/sys readdir_r(dir uintptr, entry *Dirent, result **Dirent) (res Errno)
func fdopendir(fd int) (dir uintptr, err error) {
r0, _, e1 := syscall_syscallPtr(libc_fdopendir_trampoline_addr, uintptr(fd), 0, 0)
dir = uintptr(r0)
if e1 != 0 {
err = errnoErr(e1)
}
return
}
var libc_fdopendir_trampoline_addr uintptr
/go:cgo_import_dynamic libc_fdopendir fdopendir "/usr/lib/libSystem.B.dylib"
func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) {
/ Simulate Getdirentries using fdopendir/readdir_r/closedir.
/ We store the number of entries to skip in the seek
/ offset of fd. See issue #31368.
/ It's not the full required semantics, but should handle the case
/ of calling Getdirentries or ReadDirent repeatedly.
/ It won't handle assigning the results of lseek to *basep, or handle
/ the directory being edited underfoot.
skip, err := Seek(fd, 0, 1 /* SEEK_CUR */)
if err != nil {
return 0, err
}
/ We need to duplicate the incoming file descriptor
/ because the caller expects to retain control of it, but
/ fdopendir expects to take control of its argument.
/ Just Dup'ing the file descriptor is not enough, as the
/ result shares underlying state. Use Openat to make a really
/ new file descriptor referring to the same directory.
fd2, err := Openat(fd, ".", O_RDONLY, 0)
if err != nil {
return 0, err
}
d, err := fdopendir(fd2)
if err != nil {
Close(fd2)
return 0, err
}
defer closedir(d)
var cnt int64
for {
var entry Dirent
var entryp *Dirent
e := readdir_r(d, &entry, &entryp)
if e != 0 {
return n, errnoErr(e)
}
if entryp == nil {
break
}
if skip > 0 {
skip--
cnt++
continue
}
reclen := int(entry.Reclen)
if reclen > len(buf) {
/ Not enough room. Return for now.
/ The counter will let us know where we should start up again.
/ Note: this strategy for suspending in the middle and
/ restarting is O(n^2) in the length of the directory. Oh well.
break
}
/ Copy entry into return buffer.
var s []byte
hdr := (*unsafeheader.Slice)(unsafe.Pointer(&s))
hdr.Data = unsafe.Pointer(&entry)
hdr.Cap = reclen
hdr.Len = reclen
copy(buf, s)
buf = buf[reclen:]
n += reclen
cnt++
}
/ Set the seek offset of the input fd to record
/ how many files we've already returned.
_, err = Seek(fd, cnt, 0 /* SEEK_SET */)
if err != nil {
return n, err
}
return n, nil
}