1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 Copyright 2010 Lennart Poettering
8 //#include <linux/stat.h>
13 #include <sys/xattr.h>
15 #include "alloc-util.h"
18 //#include "missing.h"
19 #include "sparse-endian.h"
20 #include "stdio-util.h"
21 //#include "string-util.h"
22 #include "time-util.h"
23 #include "xattr-util.h"
25 int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink) {
34 for (l = 100; ; l = (size_t) n + 1) {
40 n = lgetxattr(path, name, v, l);
42 n = getxattr(path, name, v, l);
44 if (n >= 0 && (size_t) n < l) {
51 if (n < 0 && errno != ERANGE)
55 n = lgetxattr(path, name, NULL, 0);
57 n = getxattr(path, name, NULL, 0);
63 int fgetxattr_malloc(int fd, const char *name, char **value) {
72 for (l = 100; ; l = (size_t) n + 1) {
77 n = fgetxattr(fd, name, v, l);
79 if (n >= 0 && (size_t) n < l) {
86 if (n < 0 && errno != ERANGE)
89 n = fgetxattr(fd, name, NULL, 0);
95 #if 0 /// UNNEEDED by elogind
99 const char *attribute,
100 void *value, size_t size,
104 char fn[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
105 _cleanup_close_ int fd = -1;
108 /* The kernel doesn't have a fgetxattrat() command, hence let's emulate one */
110 if (flags & ~(AT_SYMLINK_NOFOLLOW|AT_EMPTY_PATH))
113 if (isempty(filename)) {
114 if (!(flags & AT_EMPTY_PATH))
117 xsprintf(fn, "/proc/self/fd/%i", dirfd);
119 fd = openat(dirfd, filename, O_CLOEXEC|O_PATH|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0));
123 xsprintf(fn, "/proc/self/fd/%i", fd);
126 l = getxattr(fn, attribute, value, size);
134 static int parse_crtime(le64_t le, usec_t *usec) {
140 if (IN_SET(u, 0, (uint64_t) -1))
147 int fd_getcrtime_at(int dirfd, const char *name, usec_t *ret, int flags) {
156 if (flags & ~(AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW))
159 /* So here's the deal: the creation/birth time (crtime/btime) of a file is a relatively newly supported concept
160 * on Linux (or more strictly speaking: a concept that only recently got supported in the API, it was
161 * implemented on various file systems on the lower level since a while, but never was accessible). However, we
162 * needed a concept like that for vaccuuming algorithms and such, hence we emulated it via a user xattr for a
163 * long time. Starting with Linux 4.11 there's statx() which exposes the timestamp to userspace for the first
164 * time, where it is available. Thius function will read it, but it tries to keep some compatibility with older
165 * systems: we try to read both the crtime/btime and the xattr, and then use whatever is older. After all the
166 * concept is useful for determining how "old" a file really is, and hence using the older of the two makes
169 if (statx(dirfd, strempty(name), flags|AT_STATX_DONT_SYNC, STATX_BTIME, &sx) >= 0 &&
170 (sx.stx_mask & STATX_BTIME) &&
171 sx.stx_btime.tv_sec != 0)
172 a = (usec_t) sx.stx_btime.tv_sec * USEC_PER_SEC +
173 (usec_t) sx.stx_btime.tv_nsec / NSEC_PER_USEC;
177 r = fgetxattrat_fake(dirfd, name, "user.crtime_usec", &le, sizeof(le), flags, &n);
182 r = parse_crtime(le, &b);
185 if (a != USEC_INFINITY) {
193 if (a != USEC_INFINITY)
201 int fd_getcrtime(int fd, usec_t *ret) {
202 return fd_getcrtime_at(fd, NULL, ret, AT_EMPTY_PATH);
205 int path_getcrtime(const char *p, usec_t *ret) {
206 return fd_getcrtime_at(AT_FDCWD, p, ret, 0);
209 int fd_setcrtime(int fd, usec_t usec) {
214 if (IN_SET(usec, 0, USEC_INFINITY))
215 usec = now(CLOCK_REALTIME);
217 le = htole64((uint64_t) usec);
218 if (fsetxattr(fd, "user.crtime_usec", &le, sizeof(le), 0) < 0)