mirror of
https://github.com/rwinkhart/sys.git
synced 2026-08-29 05:16:30 -04:00
Russ Cox
9a76102bfb
Make all our package sources use Go 1.17 gofmt format (adding //go:build lines). Not strictly necessary but will avoid spurious changes as files are edited. Part of //go:build change (#41184). See https://golang.org/design/draft-gobuild Change-Id: I01667f826428426a39c84717d02efa25fa44553c Reviewed-on: https://go-review.googlesource.com/c/sys/+/294490 TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com> Reviewed-by: Matt Layher <mdlayher@gmail.com> Trust: Josh Bleecher Snyder <josharian@gmail.com> Trust: Russ Cox <rsc@golang.org> Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> Run-TryBot: Russ Cox <rsc@golang.org>
109 lines
2.7 KiB
Go
109 lines
2.7 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build darwin && go1.13
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// +build darwin,go1.13
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package unix
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import (
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"unsafe"
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"golang.org/x/sys/internal/unsafeheader"
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)
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//sys closedir(dir uintptr) (err error)
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//sys readdir_r(dir uintptr, entry *Dirent, result **Dirent) (res Errno)
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func fdopendir(fd int) (dir uintptr, err error) {
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r0, _, e1 := syscall_syscallPtr(funcPC(libc_fdopendir_trampoline), uintptr(fd), 0, 0)
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dir = uintptr(r0)
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if e1 != 0 {
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err = errnoErr(e1)
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}
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return
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}
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func libc_fdopendir_trampoline()
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//go:cgo_import_dynamic libc_fdopendir fdopendir "/usr/lib/libSystem.B.dylib"
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func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) {
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// Simulate Getdirentries using fdopendir/readdir_r/closedir.
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// We store the number of entries to skip in the seek
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// offset of fd. See issue #31368.
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// It's not the full required semantics, but should handle the case
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// of calling Getdirentries or ReadDirent repeatedly.
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// It won't handle assigning the results of lseek to *basep, or handle
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// the directory being edited underfoot.
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skip, err := Seek(fd, 0, 1 /* SEEK_CUR */)
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if err != nil {
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return 0, err
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}
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// We need to duplicate the incoming file descriptor
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// because the caller expects to retain control of it, but
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// fdopendir expects to take control of its argument.
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// Just Dup'ing the file descriptor is not enough, as the
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// result shares underlying state. Use Openat to make a really
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// new file descriptor referring to the same directory.
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fd2, err := Openat(fd, ".", O_RDONLY, 0)
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if err != nil {
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return 0, err
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}
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d, err := fdopendir(fd2)
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if err != nil {
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Close(fd2)
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return 0, err
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}
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defer closedir(d)
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var cnt int64
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for {
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var entry Dirent
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var entryp *Dirent
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e := readdir_r(d, &entry, &entryp)
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if e != 0 {
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return n, errnoErr(e)
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}
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if entryp == nil {
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break
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}
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if skip > 0 {
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skip--
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cnt++
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continue
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}
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reclen := int(entry.Reclen)
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if reclen > len(buf) {
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// Not enough room. Return for now.
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// The counter will let us know where we should start up again.
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// Note: this strategy for suspending in the middle and
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// restarting is O(n^2) in the length of the directory. Oh well.
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break
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}
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// Copy entry into return buffer.
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var s []byte
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hdr := (*unsafeheader.Slice)(unsafe.Pointer(&s))
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hdr.Data = unsafe.Pointer(&entry)
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hdr.Cap = reclen
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hdr.Len = reclen
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copy(buf, s)
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buf = buf[reclen:]
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n += reclen
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cnt++
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}
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// Set the seek offset of the input fd to record
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// how many files we've already returned.
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_, err = Seek(fd, cnt, 0 /* SEEK_SET */)
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if err != nil {
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return n, err
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}
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return n, nil
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}
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