1 /* SPDX-License-Identifier: LGPL-2.1+ */
5 //#include <linux/stat.h>
10 #include <sys/xattr.h>
12 #include "alloc-util.h"
15 //#include "missing.h"
16 #include "sparse-endian.h"
17 #include "stdio-util.h"
18 //#include "string-util.h"
19 #include "time-util.h"
20 #include "xattr-util.h"
22 int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink) {
31 for (l = 100; ; l = (size_t) n + 1) {
37 n = lgetxattr(path, name, v, l);
39 n = getxattr(path, name, v, l);
41 if (n >= 0 && (size_t) n < l) {
48 if (n < 0 && errno != ERANGE)
52 n = lgetxattr(path, name, NULL, 0);
54 n = getxattr(path, name, NULL, 0);
60 int fgetxattr_malloc(int fd, const char *name, char **value) {
69 for (l = 100; ; l = (size_t) n + 1) {
74 n = fgetxattr(fd, name, v, l);
76 if (n >= 0 && (size_t) n < l) {
83 if (n < 0 && errno != ERANGE)
86 n = fgetxattr(fd, name, NULL, 0);
92 #if 0 /// UNNEEDED by elogind
96 const char *attribute,
97 void *value, size_t size,
101 char fn[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
102 _cleanup_close_ int fd = -1;
105 /* The kernel doesn't have a fgetxattrat() command, hence let's emulate one */
107 if (flags & ~(AT_SYMLINK_NOFOLLOW|AT_EMPTY_PATH))
110 if (isempty(filename)) {
111 if (!(flags & AT_EMPTY_PATH))
114 xsprintf(fn, "/proc/self/fd/%i", dirfd);
116 fd = openat(dirfd, filename, O_CLOEXEC|O_PATH|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0));
120 xsprintf(fn, "/proc/self/fd/%i", fd);
123 l = getxattr(fn, attribute, value, size);
131 static int parse_crtime(le64_t le, usec_t *usec) {
137 if (IN_SET(u, 0, (uint64_t) -1))
144 int fd_getcrtime_at(int dirfd, const char *name, usec_t *ret, int flags) {
153 if (flags & ~(AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW))
156 /* So here's the deal: the creation/birth time (crtime/btime) of a file is a relatively newly supported concept
157 * on Linux (or more strictly speaking: a concept that only recently got supported in the API, it was
158 * implemented on various file systems on the lower level since a while, but never was accessible). However, we
159 * needed a concept like that for vaccuuming algorithms and such, hence we emulated it via a user xattr for a
160 * long time. Starting with Linux 4.11 there's statx() which exposes the timestamp to userspace for the first
161 * time, where it is available. Thius function will read it, but it tries to keep some compatibility with older
162 * systems: we try to read both the crtime/btime and the xattr, and then use whatever is older. After all the
163 * concept is useful for determining how "old" a file really is, and hence using the older of the two makes
166 if (statx(dirfd, strempty(name), flags|AT_STATX_DONT_SYNC, STATX_BTIME, &sx) >= 0 &&
167 (sx.stx_mask & STATX_BTIME) &&
168 sx.stx_btime.tv_sec != 0)
169 a = (usec_t) sx.stx_btime.tv_sec * USEC_PER_SEC +
170 (usec_t) sx.stx_btime.tv_nsec / NSEC_PER_USEC;
174 r = fgetxattrat_fake(dirfd, name, "user.crtime_usec", &le, sizeof(le), flags, &n);
179 r = parse_crtime(le, &b);
182 if (a != USEC_INFINITY) {
190 if (a != USEC_INFINITY)
198 int fd_getcrtime(int fd, usec_t *ret) {
199 return fd_getcrtime_at(fd, NULL, ret, AT_EMPTY_PATH);
202 int path_getcrtime(const char *p, usec_t *ret) {
203 return fd_getcrtime_at(AT_FDCWD, p, ret, 0);
206 int fd_setcrtime(int fd, usec_t usec) {
211 if (IN_SET(usec, 0, USEC_INFINITY))
212 usec = now(CLOCK_REALTIME);
214 le = htole64((uint64_t) usec);
215 if (fsetxattr(fd, "user.crtime_usec", &le, sizeof(le), 0) < 0)