1 | /* Support for *xattr interfaces on GNU/Hurd. |
2 | Copyright (C) 2006-2022 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 | <https://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 (s1: name, s2: "gnu." , n: 4)) |
39 | return EOPNOTSUPP; |
40 | name += 4; |
41 | |
42 | if (!strcmp (s1: name, s2: "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 (dest: value, src: &st.st_author, n: sizeof st.st_author); |
55 | } |
56 | *size = sizeof st.st_author; |
57 | return 0; |
58 | } |
59 | |
60 | if (!strcmp (s1: name, s2: "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 (addr: buf, len: bufsz); |
71 | return -ERANGE; |
72 | } |
73 | if (buf != value && bufsz > 0) |
74 | { |
75 | if (value != NULL) |
76 | memcpy (dest: value, src: buf, n: bufsz); |
77 | __munmap (addr: buf, len: 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 (s1: name, s2: "gnu." , n: 4)) |
91 | return EOPNOTSUPP; |
92 | name += 4; |
93 | |
94 | if (!strcmp (s1: name, s2: "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 (dest: &id, src: value, n: 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 (s1: name, s2: "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 (addr: buf, len: 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 | } |
201 | |