xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame^] | 1 | /* Support for *xattr interfaces on GNU/Hurd. |
| 2 | Copyright (C) 2006-2016 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; if not, see |
| 17 | <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #include <hurd.h> |
| 20 | #include <hurd/xattr.h> |
| 21 | #include <string.h> |
| 22 | #include <sys/mman.h> |
| 23 | |
| 24 | /* Right now we support only a fixed set of xattr names for Hurd features. |
| 25 | There are no RPC interfaces for free-form xattr names and values. |
| 26 | |
| 27 | Name Value encoding |
| 28 | ---- ----- -------- |
| 29 | gnu.author empty if st_author==st_uid |
| 30 | uid_t giving st_author value |
| 31 | gnu.translator empty if no passive translator |
| 32 | translator and arguments: "/hurd/foo\0arg1\0arg2\0" |
| 33 | */ |
| 34 | |
| 35 | error_t |
| 36 | _hurd_xattr_get (io_t port, const char *name, void *value, size_t *size) |
| 37 | { |
| 38 | if (strncmp (name, "gnu.", 4)) |
| 39 | return EOPNOTSUPP; |
| 40 | name += 4; |
| 41 | |
| 42 | if (!strcmp (name, "author")) |
| 43 | { |
| 44 | struct stat64 st; |
| 45 | error_t err = __io_stat (port, &st); |
| 46 | if (err) |
| 47 | return err; |
| 48 | if (st.st_author == st.st_uid) |
| 49 | *size = 0; |
| 50 | else if (value) |
| 51 | { |
| 52 | if (*size < sizeof st.st_author) |
| 53 | return ERANGE; |
| 54 | memcpy (value, &st.st_author, sizeof st.st_author); |
| 55 | } |
| 56 | *size = sizeof st.st_author; |
| 57 | return 0; |
| 58 | } |
| 59 | |
| 60 | if (!strcmp (name, "translator")) |
| 61 | { |
| 62 | char *buf = value; |
| 63 | size_t bufsz = value ? *size : 0; |
| 64 | error_t err = __file_get_translator (port, &buf, &bufsz); |
| 65 | if (err) |
| 66 | return err; |
| 67 | if (value != NULL && *size < bufsz) |
| 68 | { |
| 69 | if (buf != value) |
| 70 | munmap (buf, bufsz); |
| 71 | return -ERANGE; |
| 72 | } |
| 73 | if (buf != value && bufsz > 0) |
| 74 | { |
| 75 | if (value != NULL) |
| 76 | memcpy (value, buf, bufsz); |
| 77 | munmap (buf, bufsz); |
| 78 | } |
| 79 | *size = bufsz; |
| 80 | return 0; |
| 81 | } |
| 82 | |
| 83 | return EOPNOTSUPP; |
| 84 | } |
| 85 | |
| 86 | error_t |
| 87 | _hurd_xattr_set (io_t port, const char *name, const void *value, size_t size, |
| 88 | int flags) |
| 89 | { |
| 90 | if (strncmp (name, "gnu.", 4)) |
| 91 | return EOPNOTSUPP; |
| 92 | name += 4; |
| 93 | |
| 94 | if (!strcmp (name, "author")) |
| 95 | switch (size) |
| 96 | { |
| 97 | default: |
| 98 | return EINVAL; |
| 99 | case 0: /* "Clear" author by setting to st_uid. */ |
| 100 | { |
| 101 | struct stat64 st; |
| 102 | error_t err = __io_stat (port, &st); |
| 103 | if (err) |
| 104 | return err; |
| 105 | if (st.st_author == st.st_uid) |
| 106 | { |
| 107 | /* Nothing to do. */ |
| 108 | if (flags & XATTR_REPLACE) |
| 109 | return ENODATA; |
| 110 | return 0; |
| 111 | } |
| 112 | if (flags & XATTR_CREATE) |
| 113 | return EEXIST; |
| 114 | return __file_chauthor (port, st.st_uid); |
| 115 | } |
| 116 | case sizeof (uid_t): /* Set the author. */ |
| 117 | { |
| 118 | uid_t id; |
| 119 | memcpy (&id, value, sizeof id); |
| 120 | if (flags & (XATTR_CREATE|XATTR_REPLACE)) |
| 121 | { |
| 122 | struct stat64 st; |
| 123 | error_t err = __io_stat (port, &st); |
| 124 | if (err) |
| 125 | return err; |
| 126 | if (st.st_author == st.st_uid) |
| 127 | { |
| 128 | if (flags & XATTR_REPLACE) |
| 129 | return ENODATA; |
| 130 | } |
| 131 | else if (flags & XATTR_CREATE) |
| 132 | return EEXIST; |
| 133 | if (st.st_author == id) |
| 134 | /* Nothing to do. */ |
| 135 | return 0; |
| 136 | } |
| 137 | return __file_chauthor (port, id); |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | if (!strcmp (name, "translator")) |
| 142 | { |
| 143 | if (flags & XATTR_REPLACE) |
| 144 | { |
| 145 | /* Must make sure it's already there. */ |
| 146 | char *buf = NULL; |
| 147 | size_t bufsz = 0; |
| 148 | error_t err = __file_get_translator (port, &buf, &bufsz); |
| 149 | if (err) |
| 150 | return err; |
| 151 | if (bufsz > 0) |
| 152 | { |
| 153 | munmap (buf, bufsz); |
| 154 | return ENODATA; |
| 155 | } |
| 156 | } |
| 157 | return __file_set_translator (port, |
| 158 | FS_TRANS_SET | ((flags & XATTR_CREATE) |
| 159 | ? FS_TRANS_EXCL : 0), 0, 0, |
| 160 | value, size, |
| 161 | MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND); |
| 162 | } |
| 163 | |
| 164 | return EOPNOTSUPP; |
| 165 | } |
| 166 | |
| 167 | error_t |
| 168 | _hurd_xattr_remove (io_t port, const char *name) |
| 169 | { |
| 170 | return _hurd_xattr_set (port, name, NULL, 0, XATTR_REPLACE); |
| 171 | } |
| 172 | |
| 173 | error_t |
| 174 | _hurd_xattr_list (io_t port, void *buffer, size_t *size) |
| 175 | { |
| 176 | size_t total = 0; |
| 177 | char *bufp = buffer; |
| 178 | inline void add (const char *name, size_t len) |
| 179 | { |
| 180 | total += len; |
| 181 | if (bufp != NULL && total <= *size) |
| 182 | bufp = __mempcpy (bufp, name, len); |
| 183 | } |
| 184 | #define add(s) add (s, sizeof s) |
| 185 | |
| 186 | struct stat64 st; |
| 187 | error_t err = __io_stat (port, &st); |
| 188 | if (err) |
| 189 | return err; |
| 190 | |
| 191 | if (st.st_author != st.st_uid) |
| 192 | add ("gnu.author"); |
| 193 | if (st.st_mode & S_IPTRANS) |
| 194 | add ("gnu.translator"); |
| 195 | |
| 196 | if (buffer != NULL && total > *size) |
| 197 | return ERANGE; |
| 198 | *size = total; |
| 199 | return 0; |
| 200 | } |