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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <sys/xattr.h> | |
23 | ||
24 | #include "fd-util.h" | |
25 | #include "sparse-endian.h" | |
26 | #include "util.h" | |
27 | #include "xattr-util.h" | |
28 | ||
29 | int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink) { | |
30 | char *v; | |
31 | size_t l; | |
32 | ssize_t n; | |
33 | ||
34 | assert(path); | |
35 | assert(name); | |
36 | assert(value); | |
37 | ||
38 | for (l = 100; ; l = (size_t) n + 1) { | |
39 | v = new0(char, l); | |
40 | if (!v) | |
41 | return -ENOMEM; | |
42 | ||
43 | if (allow_symlink) | |
44 | n = lgetxattr(path, name, v, l); | |
45 | else | |
46 | n = getxattr(path, name, v, l); | |
47 | ||
48 | if (n >= 0 && (size_t) n < l) { | |
49 | *value = v; | |
50 | return n; | |
51 | } | |
52 | ||
53 | free(v); | |
54 | ||
55 | if (n < 0 && errno != ERANGE) | |
56 | return -errno; | |
57 | ||
58 | if (allow_symlink) | |
59 | n = lgetxattr(path, name, NULL, 0); | |
60 | else | |
61 | n = getxattr(path, name, NULL, 0); | |
62 | if (n < 0) | |
63 | return -errno; | |
64 | } | |
65 | } | |
66 | ||
67 | int fgetxattr_malloc(int fd, const char *name, char **value) { | |
68 | char *v; | |
69 | size_t l; | |
70 | ssize_t n; | |
71 | ||
72 | assert(fd >= 0); | |
73 | assert(name); | |
74 | assert(value); | |
75 | ||
76 | for (l = 100; ; l = (size_t) n + 1) { | |
77 | v = new0(char, l); | |
78 | if (!v) | |
79 | return -ENOMEM; | |
80 | ||
81 | n = fgetxattr(fd, name, v, l); | |
82 | ||
83 | if (n >= 0 && (size_t) n < l) { | |
84 | *value = v; | |
85 | return n; | |
86 | } | |
87 | ||
88 | free(v); | |
89 | ||
90 | if (n < 0 && errno != ERANGE) | |
91 | return -errno; | |
92 | ||
93 | n = fgetxattr(fd, name, NULL, 0); | |
94 | if (n < 0) | |
95 | return -errno; | |
96 | } | |
97 | } | |
98 | ||
99 | ssize_t fgetxattrat_fake(int dirfd, const char *filename, const char *attribute, void *value, size_t size, int flags) { | |
100 | char fn[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1]; | |
101 | _cleanup_close_ int fd = -1; | |
102 | ssize_t l; | |
103 | ||
104 | /* The kernel doesn't have a fgetxattrat() command, hence let's emulate one */ | |
105 | ||
106 | fd = openat(dirfd, filename, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_PATH|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0)); | |
107 | if (fd < 0) | |
108 | return -errno; | |
109 | ||
110 | xsprintf(fn, "/proc/self/fd/%i", fd); | |
111 | ||
112 | l = getxattr(fn, attribute, value, size); | |
113 | if (l < 0) | |
114 | return -errno; | |
115 | ||
116 | return l; | |
117 | } | |
118 | ||
119 | static int parse_crtime(le64_t le, usec_t *usec) { | |
120 | uint64_t u; | |
121 | ||
122 | assert(usec); | |
123 | ||
124 | u = le64toh(le); | |
125 | if (u == 0 || u == (uint64_t) -1) | |
126 | return -EIO; | |
127 | ||
128 | *usec = (usec_t) u; | |
129 | return 0; | |
130 | } | |
131 | ||
132 | int fd_getcrtime(int fd, usec_t *usec) { | |
133 | le64_t le; | |
134 | ssize_t n; | |
135 | ||
136 | assert(fd >= 0); | |
137 | assert(usec); | |
138 | ||
139 | /* Until Linux gets a real concept of birthtime/creation time, | |
140 | * let's fake one with xattrs */ | |
141 | ||
142 | n = fgetxattr(fd, "user.crtime_usec", &le, sizeof(le)); | |
143 | if (n < 0) | |
144 | return -errno; | |
145 | if (n != sizeof(le)) | |
146 | return -EIO; | |
147 | ||
148 | return parse_crtime(le, usec); | |
149 | } | |
150 | ||
151 | int fd_getcrtime_at(int dirfd, const char *name, usec_t *usec, int flags) { | |
152 | le64_t le; | |
153 | ssize_t n; | |
154 | ||
155 | n = fgetxattrat_fake(dirfd, name, "user.crtime_usec", &le, sizeof(le), flags); | |
156 | if (n < 0) | |
157 | return -errno; | |
158 | if (n != sizeof(le)) | |
159 | return -EIO; | |
160 | ||
161 | return parse_crtime(le, usec); | |
162 | } | |
163 | ||
164 | int path_getcrtime(const char *p, usec_t *usec) { | |
165 | le64_t le; | |
166 | ssize_t n; | |
167 | ||
168 | assert(p); | |
169 | assert(usec); | |
170 | ||
171 | n = getxattr(p, "user.crtime_usec", &le, sizeof(le)); | |
172 | if (n < 0) | |
173 | return -errno; | |
174 | if (n != sizeof(le)) | |
175 | return -EIO; | |
176 | ||
177 | return parse_crtime(le, usec); | |
178 | } | |
179 | ||
180 | int fd_setcrtime(int fd, usec_t usec) { | |
181 | le64_t le; | |
182 | ||
183 | assert(fd >= 0); | |
184 | ||
185 | if (usec <= 0) | |
186 | usec = now(CLOCK_REALTIME); | |
187 | ||
188 | le = htole64((uint64_t) usec); | |
189 | if (fsetxattr(fd, "user.crtime_usec", &le, sizeof(le), 0) < 0) | |
190 | return -errno; | |
191 | ||
192 | return 0; | |
193 | } |