Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 1 | // Copyright 2019 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 | |
khenaidoo | 7d3c558 | 2021-08-11 18:09:44 -0400 | [diff] [blame] | 5 | //go:build darwin && go1.13 |
Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 6 | // +build darwin,go1.13 |
| 7 | |
| 8 | package unix |
| 9 | |
Andrea Campanella | aec20bd | 2021-02-25 12:41:34 +0100 | [diff] [blame] | 10 | import ( |
| 11 | "unsafe" |
| 12 | |
| 13 | "golang.org/x/sys/internal/unsafeheader" |
| 14 | ) |
Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 15 | |
| 16 | //sys closedir(dir uintptr) (err error) |
| 17 | //sys readdir_r(dir uintptr, entry *Dirent, result **Dirent) (res Errno) |
| 18 | |
| 19 | func fdopendir(fd int) (dir uintptr, err error) { |
khenaidoo | 7d3c558 | 2021-08-11 18:09:44 -0400 | [diff] [blame] | 20 | r0, _, e1 := syscall_syscallPtr(libc_fdopendir_trampoline_addr, uintptr(fd), 0, 0) |
Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 21 | dir = uintptr(r0) |
| 22 | if e1 != 0 { |
| 23 | err = errnoErr(e1) |
| 24 | } |
| 25 | return |
| 26 | } |
| 27 | |
khenaidoo | 7d3c558 | 2021-08-11 18:09:44 -0400 | [diff] [blame] | 28 | var libc_fdopendir_trampoline_addr uintptr |
Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 29 | |
Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 30 | //go:cgo_import_dynamic libc_fdopendir fdopendir "/usr/lib/libSystem.B.dylib" |
| 31 | |
| 32 | func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) { |
| 33 | // Simulate Getdirentries using fdopendir/readdir_r/closedir. |
| 34 | // We store the number of entries to skip in the seek |
| 35 | // offset of fd. See issue #31368. |
| 36 | // It's not the full required semantics, but should handle the case |
| 37 | // of calling Getdirentries or ReadDirent repeatedly. |
| 38 | // It won't handle assigning the results of lseek to *basep, or handle |
| 39 | // the directory being edited underfoot. |
| 40 | skip, err := Seek(fd, 0, 1 /* SEEK_CUR */) |
| 41 | if err != nil { |
| 42 | return 0, err |
| 43 | } |
| 44 | |
| 45 | // We need to duplicate the incoming file descriptor |
| 46 | // because the caller expects to retain control of it, but |
| 47 | // fdopendir expects to take control of its argument. |
| 48 | // Just Dup'ing the file descriptor is not enough, as the |
| 49 | // result shares underlying state. Use Openat to make a really |
| 50 | // new file descriptor referring to the same directory. |
| 51 | fd2, err := Openat(fd, ".", O_RDONLY, 0) |
| 52 | if err != nil { |
| 53 | return 0, err |
| 54 | } |
| 55 | d, err := fdopendir(fd2) |
| 56 | if err != nil { |
| 57 | Close(fd2) |
| 58 | return 0, err |
| 59 | } |
| 60 | defer closedir(d) |
| 61 | |
| 62 | var cnt int64 |
| 63 | for { |
| 64 | var entry Dirent |
| 65 | var entryp *Dirent |
| 66 | e := readdir_r(d, &entry, &entryp) |
| 67 | if e != 0 { |
| 68 | return n, errnoErr(e) |
| 69 | } |
| 70 | if entryp == nil { |
| 71 | break |
| 72 | } |
| 73 | if skip > 0 { |
| 74 | skip-- |
| 75 | cnt++ |
| 76 | continue |
| 77 | } |
Andrea Campanella | aec20bd | 2021-02-25 12:41:34 +0100 | [diff] [blame] | 78 | |
Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 79 | reclen := int(entry.Reclen) |
| 80 | if reclen > len(buf) { |
| 81 | // Not enough room. Return for now. |
| 82 | // The counter will let us know where we should start up again. |
| 83 | // Note: this strategy for suspending in the middle and |
| 84 | // restarting is O(n^2) in the length of the directory. Oh well. |
| 85 | break |
| 86 | } |
Andrea Campanella | aec20bd | 2021-02-25 12:41:34 +0100 | [diff] [blame] | 87 | |
Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 88 | // Copy entry into return buffer. |
Andrea Campanella | aec20bd | 2021-02-25 12:41:34 +0100 | [diff] [blame] | 89 | var s []byte |
| 90 | hdr := (*unsafeheader.Slice)(unsafe.Pointer(&s)) |
| 91 | hdr.Data = unsafe.Pointer(&entry) |
| 92 | hdr.Cap = reclen |
| 93 | hdr.Len = reclen |
| 94 | copy(buf, s) |
| 95 | |
Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 96 | buf = buf[reclen:] |
| 97 | n += reclen |
| 98 | cnt++ |
| 99 | } |
| 100 | // Set the seek offset of the input fd to record |
| 101 | // how many files we've already returned. |
| 102 | _, err = Seek(fd, cnt, 0 /* SEEK_SET */) |
| 103 | if err != nil { |
| 104 | return n, err |
| 105 | } |
| 106 | |
| 107 | return n, nil |
| 108 | } |