]>
Commit | Line | Data |
---|---|---|
53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
89a5a90c | 2 | /*** |
89a5a90c | 3 | Copyright 2010 Lennart Poettering |
89a5a90c LP |
4 | ***/ |
5 | ||
11c3a366 TA |
6 | #include <errno.h> |
7 | #include <fcntl.h> | |
4c2e1b39 | 8 | #include <linux/stat.h> |
11c3a366 TA |
9 | #include <stdint.h> |
10 | #include <stdlib.h> | |
11 | #include <string.h> | |
12 | #include <sys/time.h> | |
89a5a90c LP |
13 | #include <sys/xattr.h> |
14 | ||
b5efdb8a | 15 | #include "alloc-util.h" |
89a5a90c | 16 | #include "fd-util.h" |
11c3a366 | 17 | #include "macro.h" |
4c2e1b39 | 18 | #include "missing.h" |
93cc7779 | 19 | #include "sparse-endian.h" |
15a5e950 | 20 | #include "stdio-util.h" |
1133dea4 | 21 | #include "string-util.h" |
93cc7779 | 22 | #include "time-util.h" |
89a5a90c LP |
23 | #include "xattr-util.h" |
24 | ||
25 | int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink) { | |
26 | char *v; | |
27 | size_t l; | |
28 | ssize_t n; | |
29 | ||
30 | assert(path); | |
31 | assert(name); | |
32 | assert(value); | |
33 | ||
34 | for (l = 100; ; l = (size_t) n + 1) { | |
35 | v = new0(char, l); | |
36 | if (!v) | |
37 | return -ENOMEM; | |
38 | ||
39 | if (allow_symlink) | |
40 | n = lgetxattr(path, name, v, l); | |
41 | else | |
42 | n = getxattr(path, name, v, l); | |
43 | ||
44 | if (n >= 0 && (size_t) n < l) { | |
45 | *value = v; | |
46 | return n; | |
47 | } | |
48 | ||
49 | free(v); | |
50 | ||
51 | if (n < 0 && errno != ERANGE) | |
52 | return -errno; | |
53 | ||
54 | if (allow_symlink) | |
55 | n = lgetxattr(path, name, NULL, 0); | |
56 | else | |
57 | n = getxattr(path, name, NULL, 0); | |
58 | if (n < 0) | |
59 | return -errno; | |
60 | } | |
61 | } | |
62 | ||
63 | int fgetxattr_malloc(int fd, const char *name, char **value) { | |
64 | char *v; | |
65 | size_t l; | |
66 | ssize_t n; | |
67 | ||
68 | assert(fd >= 0); | |
69 | assert(name); | |
70 | assert(value); | |
71 | ||
72 | for (l = 100; ; l = (size_t) n + 1) { | |
73 | v = new0(char, l); | |
74 | if (!v) | |
75 | return -ENOMEM; | |
76 | ||
77 | n = fgetxattr(fd, name, v, l); | |
78 | ||
79 | if (n >= 0 && (size_t) n < l) { | |
80 | *value = v; | |
81 | return n; | |
82 | } | |
83 | ||
84 | free(v); | |
85 | ||
86 | if (n < 0 && errno != ERANGE) | |
87 | return -errno; | |
88 | ||
89 | n = fgetxattr(fd, name, NULL, 0); | |
90 | if (n < 0) | |
91 | return -errno; | |
92 | } | |
93 | } | |
94 | ||
e4de6259 ZJS |
95 | int fgetxattrat_fake( |
96 | int dirfd, | |
97 | const char *filename, | |
98 | const char *attribute, | |
99 | void *value, size_t size, | |
100 | int flags, | |
101 | size_t *ret_size) { | |
102 | ||
fbd0b64f | 103 | char fn[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1]; |
89a5a90c LP |
104 | _cleanup_close_ int fd = -1; |
105 | ssize_t l; | |
106 | ||
107 | /* The kernel doesn't have a fgetxattrat() command, hence let's emulate one */ | |
108 | ||
1133dea4 LP |
109 | if (flags & ~(AT_SYMLINK_NOFOLLOW|AT_EMPTY_PATH)) |
110 | return -EINVAL; | |
111 | ||
112 | if (isempty(filename)) { | |
113 | if (!(flags & AT_EMPTY_PATH)) | |
114 | return -EINVAL; | |
89a5a90c | 115 | |
1133dea4 LP |
116 | xsprintf(fn, "/proc/self/fd/%i", dirfd); |
117 | } else { | |
118 | fd = openat(dirfd, filename, O_CLOEXEC|O_PATH|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0)); | |
119 | if (fd < 0) | |
120 | return -errno; | |
121 | ||
122 | xsprintf(fn, "/proc/self/fd/%i", fd); | |
123 | } | |
89a5a90c LP |
124 | |
125 | l = getxattr(fn, attribute, value, size); | |
126 | if (l < 0) | |
127 | return -errno; | |
128 | ||
e4de6259 ZJS |
129 | *ret_size = l; |
130 | return 0; | |
89a5a90c LP |
131 | } |
132 | ||
133 | static int parse_crtime(le64_t le, usec_t *usec) { | |
134 | uint64_t u; | |
135 | ||
136 | assert(usec); | |
137 | ||
138 | u = le64toh(le); | |
4c701096 | 139 | if (IN_SET(u, 0, (uint64_t) -1)) |
89a5a90c LP |
140 | return -EIO; |
141 | ||
142 | *usec = (usec_t) u; | |
143 | return 0; | |
144 | } | |
145 | ||
4c2e1b39 | 146 | int fd_getcrtime_at(int dirfd, const char *name, usec_t *ret, int flags) { |
5187dd2c | 147 | struct_statx sx; |
4c2e1b39 | 148 | usec_t a, b; |
89a5a90c | 149 | le64_t le; |
e4de6259 | 150 | size_t n; |
4c2e1b39 | 151 | int r; |
89a5a90c | 152 | |
4c2e1b39 | 153 | assert(ret); |
89a5a90c | 154 | |
4c2e1b39 LP |
155 | if (flags & ~(AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW)) |
156 | return -EINVAL; | |
89a5a90c | 157 | |
4c2e1b39 LP |
158 | /* So here's the deal: the creation/birth time (crtime/btime) of a file is a relatively newly supported concept |
159 | * on Linux (or more strictly speaking: a concept that only recently got supported in the API, it was | |
160 | * implemented on various file systems on the lower level since a while, but never was accessible). However, we | |
161 | * needed a concept like that for vaccuuming algorithms and such, hence we emulated it via a user xattr for a | |
162 | * long time. Starting with Linux 4.11 there's statx() which exposes the timestamp to userspace for the first | |
163 | * time, where it is available. Thius function will read it, but it tries to keep some compatibility with older | |
164 | * systems: we try to read both the crtime/btime and the xattr, and then use whatever is older. After all the | |
165 | * concept is useful for determining how "old" a file really is, and hence using the older of the two makes | |
166 | * most sense. */ | |
167 | ||
168 | if (statx(dirfd, strempty(name), flags|AT_STATX_DONT_SYNC, STATX_BTIME, &sx) >= 0 && | |
169 | (sx.stx_mask & STATX_BTIME) && | |
170 | sx.stx_btime.tv_sec != 0) | |
171 | a = (usec_t) sx.stx_btime.tv_sec * USEC_PER_SEC + | |
172 | (usec_t) sx.stx_btime.tv_nsec / NSEC_PER_USEC; | |
173 | else | |
174 | a = USEC_INFINITY; | |
89a5a90c | 175 | |
e4de6259 ZJS |
176 | r = fgetxattrat_fake(dirfd, name, "user.crtime_usec", &le, sizeof(le), flags, &n); |
177 | if (r >= 0) { | |
178 | if (n != sizeof(le)) | |
179 | r = -EIO; | |
180 | else | |
181 | r = parse_crtime(le, &b); | |
182 | } | |
4c2e1b39 LP |
183 | if (r < 0) { |
184 | if (a != USEC_INFINITY) { | |
185 | *ret = a; | |
186 | return 0; | |
187 | } | |
89a5a90c | 188 | |
4c2e1b39 LP |
189 | return r; |
190 | } | |
89a5a90c | 191 | |
4c2e1b39 LP |
192 | if (a != USEC_INFINITY) |
193 | *ret = MIN(a, b); | |
194 | else | |
195 | *ret = b; | |
89a5a90c | 196 | |
4c2e1b39 LP |
197 | return 0; |
198 | } | |
89a5a90c | 199 | |
4c2e1b39 LP |
200 | int fd_getcrtime(int fd, usec_t *ret) { |
201 | return fd_getcrtime_at(fd, NULL, ret, AT_EMPTY_PATH); | |
202 | } | |
89a5a90c | 203 | |
4c2e1b39 LP |
204 | int path_getcrtime(const char *p, usec_t *ret) { |
205 | return fd_getcrtime_at(AT_FDCWD, p, ret, 0); | |
89a5a90c LP |
206 | } |
207 | ||
208 | int fd_setcrtime(int fd, usec_t usec) { | |
209 | le64_t le; | |
210 | ||
211 | assert(fd >= 0); | |
212 | ||
4c2e1b39 | 213 | if (IN_SET(usec, 0, USEC_INFINITY)) |
89a5a90c LP |
214 | usec = now(CLOCK_REALTIME); |
215 | ||
216 | le = htole64((uint64_t) usec); | |
217 | if (fsetxattr(fd, "user.crtime_usec", &le, sizeof(le), 0) < 0) | |
218 | return -errno; | |
219 | ||
220 | return 0; | |
221 | } |