William Kurkian | ea86948 | 2019-04-09 15:16:11 -0400 | [diff] [blame] | 1 | // Copyright 2018 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 | // +build freebsd netbsd |
| 6 | |
| 7 | package unix |
| 8 | |
| 9 | import ( |
| 10 | "strings" |
| 11 | "unsafe" |
| 12 | ) |
| 13 | |
| 14 | // Derive extattr namespace and attribute name |
| 15 | |
| 16 | func xattrnamespace(fullattr string) (ns int, attr string, err error) { |
| 17 | s := strings.IndexByte(fullattr, '.') |
| 18 | if s == -1 { |
| 19 | return -1, "", ENOATTR |
| 20 | } |
| 21 | |
| 22 | namespace := fullattr[0:s] |
| 23 | attr = fullattr[s+1:] |
| 24 | |
| 25 | switch namespace { |
| 26 | case "user": |
| 27 | return EXTATTR_NAMESPACE_USER, attr, nil |
| 28 | case "system": |
| 29 | return EXTATTR_NAMESPACE_SYSTEM, attr, nil |
| 30 | default: |
| 31 | return -1, "", ENOATTR |
| 32 | } |
| 33 | } |
| 34 | |
| 35 | func initxattrdest(dest []byte, idx int) (d unsafe.Pointer) { |
| 36 | if len(dest) > idx { |
| 37 | return unsafe.Pointer(&dest[idx]) |
| 38 | } else { |
| 39 | return unsafe.Pointer(_zero) |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | // FreeBSD and NetBSD implement their own syscalls to handle extended attributes |
| 44 | |
| 45 | func Getxattr(file string, attr string, dest []byte) (sz int, err error) { |
| 46 | d := initxattrdest(dest, 0) |
| 47 | destsize := len(dest) |
| 48 | |
| 49 | nsid, a, err := xattrnamespace(attr) |
| 50 | if err != nil { |
| 51 | return -1, err |
| 52 | } |
| 53 | |
| 54 | return ExtattrGetFile(file, nsid, a, uintptr(d), destsize) |
| 55 | } |
| 56 | |
| 57 | func Fgetxattr(fd int, attr string, dest []byte) (sz int, err error) { |
| 58 | d := initxattrdest(dest, 0) |
| 59 | destsize := len(dest) |
| 60 | |
| 61 | nsid, a, err := xattrnamespace(attr) |
| 62 | if err != nil { |
| 63 | return -1, err |
| 64 | } |
| 65 | |
| 66 | return ExtattrGetFd(fd, nsid, a, uintptr(d), destsize) |
| 67 | } |
| 68 | |
| 69 | func Lgetxattr(link string, attr string, dest []byte) (sz int, err error) { |
| 70 | d := initxattrdest(dest, 0) |
| 71 | destsize := len(dest) |
| 72 | |
| 73 | nsid, a, err := xattrnamespace(attr) |
| 74 | if err != nil { |
| 75 | return -1, err |
| 76 | } |
| 77 | |
| 78 | return ExtattrGetLink(link, nsid, a, uintptr(d), destsize) |
| 79 | } |
| 80 | |
| 81 | // flags are unused on FreeBSD |
| 82 | |
| 83 | func Fsetxattr(fd int, attr string, data []byte, flags int) (err error) { |
| 84 | var d unsafe.Pointer |
| 85 | if len(data) > 0 { |
| 86 | d = unsafe.Pointer(&data[0]) |
| 87 | } |
| 88 | datasiz := len(data) |
| 89 | |
| 90 | nsid, a, err := xattrnamespace(attr) |
| 91 | if err != nil { |
| 92 | return |
| 93 | } |
| 94 | |
| 95 | _, err = ExtattrSetFd(fd, nsid, a, uintptr(d), datasiz) |
| 96 | return |
| 97 | } |
| 98 | |
| 99 | func Setxattr(file string, attr string, data []byte, flags int) (err error) { |
| 100 | var d unsafe.Pointer |
| 101 | if len(data) > 0 { |
| 102 | d = unsafe.Pointer(&data[0]) |
| 103 | } |
| 104 | datasiz := len(data) |
| 105 | |
| 106 | nsid, a, err := xattrnamespace(attr) |
| 107 | if err != nil { |
| 108 | return |
| 109 | } |
| 110 | |
| 111 | _, err = ExtattrSetFile(file, nsid, a, uintptr(d), datasiz) |
| 112 | return |
| 113 | } |
| 114 | |
| 115 | func Lsetxattr(link string, attr string, data []byte, flags int) (err error) { |
| 116 | var d unsafe.Pointer |
| 117 | if len(data) > 0 { |
| 118 | d = unsafe.Pointer(&data[0]) |
| 119 | } |
| 120 | datasiz := len(data) |
| 121 | |
| 122 | nsid, a, err := xattrnamespace(attr) |
| 123 | if err != nil { |
| 124 | return |
| 125 | } |
| 126 | |
| 127 | _, err = ExtattrSetLink(link, nsid, a, uintptr(d), datasiz) |
| 128 | return |
| 129 | } |
| 130 | |
| 131 | func Removexattr(file string, attr string) (err error) { |
| 132 | nsid, a, err := xattrnamespace(attr) |
| 133 | if err != nil { |
| 134 | return |
| 135 | } |
| 136 | |
| 137 | err = ExtattrDeleteFile(file, nsid, a) |
| 138 | return |
| 139 | } |
| 140 | |
| 141 | func Fremovexattr(fd int, attr string) (err error) { |
| 142 | nsid, a, err := xattrnamespace(attr) |
| 143 | if err != nil { |
| 144 | return |
| 145 | } |
| 146 | |
| 147 | err = ExtattrDeleteFd(fd, nsid, a) |
| 148 | return |
| 149 | } |
| 150 | |
| 151 | func Lremovexattr(link string, attr string) (err error) { |
| 152 | nsid, a, err := xattrnamespace(attr) |
| 153 | if err != nil { |
| 154 | return |
| 155 | } |
| 156 | |
| 157 | err = ExtattrDeleteLink(link, nsid, a) |
| 158 | return |
| 159 | } |
| 160 | |
| 161 | func Listxattr(file string, dest []byte) (sz int, err error) { |
| 162 | d := initxattrdest(dest, 0) |
| 163 | destsiz := len(dest) |
| 164 | |
| 165 | // FreeBSD won't allow you to list xattrs from multiple namespaces |
| 166 | s := 0 |
| 167 | for _, nsid := range [...]int{EXTATTR_NAMESPACE_USER, EXTATTR_NAMESPACE_SYSTEM} { |
| 168 | stmp, e := ExtattrListFile(file, nsid, uintptr(d), destsiz) |
| 169 | |
| 170 | /* Errors accessing system attrs are ignored so that |
| 171 | * we can implement the Linux-like behavior of omitting errors that |
| 172 | * we don't have read permissions on |
| 173 | * |
| 174 | * Linux will still error if we ask for user attributes on a file that |
| 175 | * we don't have read permissions on, so don't ignore those errors |
| 176 | */ |
| 177 | if e != nil && e == EPERM && nsid != EXTATTR_NAMESPACE_USER { |
| 178 | continue |
| 179 | } else if e != nil { |
| 180 | return s, e |
| 181 | } |
| 182 | |
| 183 | s += stmp |
| 184 | destsiz -= s |
| 185 | if destsiz < 0 { |
| 186 | destsiz = 0 |
| 187 | } |
| 188 | d = initxattrdest(dest, s) |
| 189 | } |
| 190 | |
| 191 | return s, nil |
| 192 | } |
| 193 | |
| 194 | func Flistxattr(fd int, dest []byte) (sz int, err error) { |
| 195 | d := initxattrdest(dest, 0) |
| 196 | destsiz := len(dest) |
| 197 | |
| 198 | s := 0 |
| 199 | for _, nsid := range [...]int{EXTATTR_NAMESPACE_USER, EXTATTR_NAMESPACE_SYSTEM} { |
| 200 | stmp, e := ExtattrListFd(fd, nsid, uintptr(d), destsiz) |
| 201 | if e != nil && e == EPERM && nsid != EXTATTR_NAMESPACE_USER { |
| 202 | continue |
| 203 | } else if e != nil { |
| 204 | return s, e |
| 205 | } |
| 206 | |
| 207 | s += stmp |
| 208 | destsiz -= s |
| 209 | if destsiz < 0 { |
| 210 | destsiz = 0 |
| 211 | } |
| 212 | d = initxattrdest(dest, s) |
| 213 | } |
| 214 | |
| 215 | return s, nil |
| 216 | } |
| 217 | |
| 218 | func Llistxattr(link string, dest []byte) (sz int, err error) { |
| 219 | d := initxattrdest(dest, 0) |
| 220 | destsiz := len(dest) |
| 221 | |
| 222 | s := 0 |
| 223 | for _, nsid := range [...]int{EXTATTR_NAMESPACE_USER, EXTATTR_NAMESPACE_SYSTEM} { |
| 224 | stmp, e := ExtattrListLink(link, nsid, uintptr(d), destsiz) |
| 225 | if e != nil && e == EPERM && nsid != EXTATTR_NAMESPACE_USER { |
| 226 | continue |
| 227 | } else if e != nil { |
| 228 | return s, e |
| 229 | } |
| 230 | |
| 231 | s += stmp |
| 232 | destsiz -= s |
| 233 | if destsiz < 0 { |
| 234 | destsiz = 0 |
| 235 | } |
| 236 | d = initxattrdest(dest, s) |
| 237 | } |
| 238 | |
| 239 | return s, nil |
| 240 | } |