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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
89a5a90c | 2 | |
11c3a366 TA |
3 | #include <errno.h> |
4 | #include <fcntl.h> | |
5 | #include <stdint.h> | |
6 | #include <stdlib.h> | |
7 | #include <string.h> | |
8 | #include <sys/time.h> | |
89a5a90c LP |
9 | #include <sys/xattr.h> |
10 | ||
b5efdb8a | 11 | #include "alloc-util.h" |
89a5a90c | 12 | #include "fd-util.h" |
11c3a366 | 13 | #include "macro.h" |
4c2e1b39 | 14 | #include "missing.h" |
93cc7779 | 15 | #include "sparse-endian.h" |
15a5e950 | 16 | #include "stdio-util.h" |
1133dea4 | 17 | #include "string-util.h" |
93cc7779 | 18 | #include "time-util.h" |
89a5a90c LP |
19 | #include "xattr-util.h" |
20 | ||
21 | int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink) { | |
22 | char *v; | |
23 | size_t l; | |
24 | ssize_t n; | |
25 | ||
26 | assert(path); | |
27 | assert(name); | |
28 | assert(value); | |
29 | ||
5373172e | 30 | for (l = 100; ; l = (size_t) n + 1 /* extra byte to make sure this remains NUL suffixed */) { |
89a5a90c LP |
31 | v = new0(char, l); |
32 | if (!v) | |
33 | return -ENOMEM; | |
34 | ||
35 | if (allow_symlink) | |
36 | n = lgetxattr(path, name, v, l); | |
37 | else | |
38 | n = getxattr(path, name, v, l); | |
89a5a90c LP |
39 | if (n >= 0 && (size_t) n < l) { |
40 | *value = v; | |
41 | return n; | |
42 | } | |
43 | ||
44 | free(v); | |
45 | ||
46 | if (n < 0 && errno != ERANGE) | |
47 | return -errno; | |
48 | ||
49 | if (allow_symlink) | |
50 | n = lgetxattr(path, name, NULL, 0); | |
51 | else | |
52 | n = getxattr(path, name, NULL, 0); | |
53 | if (n < 0) | |
54 | return -errno; | |
55 | } | |
56 | } | |
57 | ||
58 | int fgetxattr_malloc(int fd, const char *name, char **value) { | |
59 | char *v; | |
60 | size_t l; | |
61 | ssize_t n; | |
62 | ||
63 | assert(fd >= 0); | |
64 | assert(name); | |
65 | assert(value); | |
66 | ||
5373172e | 67 | for (l = 100;; l = (size_t) n + 1 /* extra byte to make sure this remains NUL suffixed */) { |
89a5a90c LP |
68 | v = new0(char, l); |
69 | if (!v) | |
70 | return -ENOMEM; | |
71 | ||
72 | n = fgetxattr(fd, name, v, l); | |
89a5a90c LP |
73 | if (n >= 0 && (size_t) n < l) { |
74 | *value = v; | |
75 | return n; | |
76 | } | |
77 | ||
78 | free(v); | |
79 | ||
80 | if (n < 0 && errno != ERANGE) | |
81 | return -errno; | |
82 | ||
83 | n = fgetxattr(fd, name, NULL, 0); | |
84 | if (n < 0) | |
85 | return -errno; | |
86 | } | |
87 | } | |
88 | ||
e4de6259 ZJS |
89 | int fgetxattrat_fake( |
90 | int dirfd, | |
91 | const char *filename, | |
92 | const char *attribute, | |
93 | void *value, size_t size, | |
94 | int flags, | |
95 | size_t *ret_size) { | |
96 | ||
fbd0b64f | 97 | char fn[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1]; |
89a5a90c LP |
98 | _cleanup_close_ int fd = -1; |
99 | ssize_t l; | |
100 | ||
101 | /* The kernel doesn't have a fgetxattrat() command, hence let's emulate one */ | |
102 | ||
1133dea4 LP |
103 | if (flags & ~(AT_SYMLINK_NOFOLLOW|AT_EMPTY_PATH)) |
104 | return -EINVAL; | |
105 | ||
106 | if (isempty(filename)) { | |
107 | if (!(flags & AT_EMPTY_PATH)) | |
108 | return -EINVAL; | |
89a5a90c | 109 | |
1133dea4 LP |
110 | xsprintf(fn, "/proc/self/fd/%i", dirfd); |
111 | } else { | |
112 | fd = openat(dirfd, filename, O_CLOEXEC|O_PATH|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0)); | |
113 | if (fd < 0) | |
114 | return -errno; | |
115 | ||
116 | xsprintf(fn, "/proc/self/fd/%i", fd); | |
117 | } | |
89a5a90c LP |
118 | |
119 | l = getxattr(fn, attribute, value, size); | |
120 | if (l < 0) | |
121 | return -errno; | |
122 | ||
e4de6259 ZJS |
123 | *ret_size = l; |
124 | return 0; | |
89a5a90c LP |
125 | } |
126 | ||
127 | static int parse_crtime(le64_t le, usec_t *usec) { | |
128 | uint64_t u; | |
129 | ||
130 | assert(usec); | |
131 | ||
132 | u = le64toh(le); | |
4c701096 | 133 | if (IN_SET(u, 0, (uint64_t) -1)) |
89a5a90c LP |
134 | return -EIO; |
135 | ||
136 | *usec = (usec_t) u; | |
137 | return 0; | |
138 | } | |
139 | ||
4c2e1b39 | 140 | int fd_getcrtime_at(int dirfd, const char *name, usec_t *ret, int flags) { |
08995a6b ZJS |
141 | struct_statx sx |
142 | #if HAS_FEATURE_MEMORY_SANITIZER | |
143 | = {} | |
144 | # warning "Explicitly initializing struct statx, to work around msan limitation. Please remove as soon as msan has been updated to not require this." | |
145 | #endif | |
146 | ; | |
4c2e1b39 | 147 | usec_t a, b; |
89a5a90c | 148 | le64_t le; |
e4de6259 | 149 | size_t n; |
4c2e1b39 | 150 | int r; |
89a5a90c | 151 | |
4c2e1b39 | 152 | assert(ret); |
89a5a90c | 153 | |
4c2e1b39 LP |
154 | if (flags & ~(AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW)) |
155 | return -EINVAL; | |
89a5a90c | 156 | |
4c2e1b39 LP |
157 | /* So here's the deal: the creation/birth time (crtime/btime) of a file is a relatively newly supported concept |
158 | * on Linux (or more strictly speaking: a concept that only recently got supported in the API, it was | |
159 | * implemented on various file systems on the lower level since a while, but never was accessible). However, we | |
160 | * needed a concept like that for vaccuuming algorithms and such, hence we emulated it via a user xattr for a | |
161 | * long time. Starting with Linux 4.11 there's statx() which exposes the timestamp to userspace for the first | |
162 | * time, where it is available. Thius function will read it, but it tries to keep some compatibility with older | |
163 | * systems: we try to read both the crtime/btime and the xattr, and then use whatever is older. After all the | |
164 | * concept is useful for determining how "old" a file really is, and hence using the older of the two makes | |
165 | * most sense. */ | |
166 | ||
167 | if (statx(dirfd, strempty(name), flags|AT_STATX_DONT_SYNC, STATX_BTIME, &sx) >= 0 && | |
168 | (sx.stx_mask & STATX_BTIME) && | |
169 | sx.stx_btime.tv_sec != 0) | |
170 | a = (usec_t) sx.stx_btime.tv_sec * USEC_PER_SEC + | |
171 | (usec_t) sx.stx_btime.tv_nsec / NSEC_PER_USEC; | |
172 | else | |
173 | a = USEC_INFINITY; | |
89a5a90c | 174 | |
e4de6259 ZJS |
175 | r = fgetxattrat_fake(dirfd, name, "user.crtime_usec", &le, sizeof(le), flags, &n); |
176 | if (r >= 0) { | |
177 | if (n != sizeof(le)) | |
178 | r = -EIO; | |
179 | else | |
180 | r = parse_crtime(le, &b); | |
181 | } | |
4c2e1b39 LP |
182 | if (r < 0) { |
183 | if (a != USEC_INFINITY) { | |
184 | *ret = a; | |
185 | return 0; | |
186 | } | |
89a5a90c | 187 | |
4c2e1b39 LP |
188 | return r; |
189 | } | |
89a5a90c | 190 | |
4c2e1b39 LP |
191 | if (a != USEC_INFINITY) |
192 | *ret = MIN(a, b); | |
193 | else | |
194 | *ret = b; | |
89a5a90c | 195 | |
4c2e1b39 LP |
196 | return 0; |
197 | } | |
89a5a90c | 198 | |
4c2e1b39 LP |
199 | int fd_getcrtime(int fd, usec_t *ret) { |
200 | return fd_getcrtime_at(fd, NULL, ret, AT_EMPTY_PATH); | |
201 | } | |
89a5a90c | 202 | |
4c2e1b39 LP |
203 | int path_getcrtime(const char *p, usec_t *ret) { |
204 | return fd_getcrtime_at(AT_FDCWD, p, ret, 0); | |
89a5a90c LP |
205 | } |
206 | ||
207 | int fd_setcrtime(int fd, usec_t usec) { | |
208 | le64_t le; | |
209 | ||
210 | assert(fd >= 0); | |
211 | ||
4c2e1b39 | 212 | if (IN_SET(usec, 0, USEC_INFINITY)) |
89a5a90c LP |
213 | usec = now(CLOCK_REALTIME); |
214 | ||
215 | le = htole64((uint64_t) usec); | |
216 | if (fsetxattr(fd, "user.crtime_usec", &le, sizeof(le), 0) < 0) | |
217 | return -errno; | |
218 | ||
219 | return 0; | |
220 | } |