+/* SPDX-License-Identifier: LGPL-2.1+ */
/***
- This file is part of systemd.
-
Copyright 2010 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <fcntl.h>
+//#include <linux/stat.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "macro.h"
+//#include "missing.h"
#include "sparse-endian.h"
#include "stdio-util.h"
+//#include "string-util.h"
#include "time-util.h"
#include "xattr-util.h"
}
#if 0 /// UNNEEDED by elogind
-ssize_t fgetxattrat_fake(int dirfd, const char *filename, const char *attribute, void *value, size_t size, int flags) {
- char fn[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
+int fgetxattrat_fake(
+ int dirfd,
+ const char *filename,
+ const char *attribute,
+ void *value, size_t size,
+ int flags,
+ size_t *ret_size) {
+
+ char fn[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
_cleanup_close_ int fd = -1;
ssize_t l;
/* The kernel doesn't have a fgetxattrat() command, hence let's emulate one */
- fd = openat(dirfd, filename, O_CLOEXEC|O_PATH|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0));
- if (fd < 0)
- return -errno;
+ if (flags & ~(AT_SYMLINK_NOFOLLOW|AT_EMPTY_PATH))
+ return -EINVAL;
- xsprintf(fn, "/proc/self/fd/%i", fd);
+ if (isempty(filename)) {
+ if (!(flags & AT_EMPTY_PATH))
+ return -EINVAL;
+
+ xsprintf(fn, "/proc/self/fd/%i", dirfd);
+ } else {
+ fd = openat(dirfd, filename, O_CLOEXEC|O_PATH|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0));
+ if (fd < 0)
+ return -errno;
+
+ xsprintf(fn, "/proc/self/fd/%i", fd);
+ }
l = getxattr(fn, attribute, value, size);
if (l < 0)
return -errno;
- return l;
+ *ret_size = l;
+ return 0;
}
static int parse_crtime(le64_t le, usec_t *usec) {
assert(usec);
u = le64toh(le);
- if (u == 0 || u == (uint64_t) -1)
+ if (IN_SET(u, 0, (uint64_t) -1))
return -EIO;
*usec = (usec_t) u;
return 0;
}
-int fd_getcrtime(int fd, usec_t *usec) {
+int fd_getcrtime_at(int dirfd, const char *name, usec_t *ret, int flags) {
+ struct_statx sx;
+ usec_t a, b;
le64_t le;
- ssize_t n;
+ size_t n;
+ int r;
+
+ assert(ret);
+
+ if (flags & ~(AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW))
+ return -EINVAL;
+
+ /* So here's the deal: the creation/birth time (crtime/btime) of a file is a relatively newly supported concept
+ * on Linux (or more strictly speaking: a concept that only recently got supported in the API, it was
+ * implemented on various file systems on the lower level since a while, but never was accessible). However, we
+ * needed a concept like that for vaccuuming algorithms and such, hence we emulated it via a user xattr for a
+ * long time. Starting with Linux 4.11 there's statx() which exposes the timestamp to userspace for the first
+ * time, where it is available. Thius function will read it, but it tries to keep some compatibility with older
+ * systems: we try to read both the crtime/btime and the xattr, and then use whatever is older. After all the
+ * concept is useful for determining how "old" a file really is, and hence using the older of the two makes
+ * most sense. */
+
+ if (statx(dirfd, strempty(name), flags|AT_STATX_DONT_SYNC, STATX_BTIME, &sx) >= 0 &&
+ (sx.stx_mask & STATX_BTIME) &&
+ sx.stx_btime.tv_sec != 0)
+ a = (usec_t) sx.stx_btime.tv_sec * USEC_PER_SEC +
+ (usec_t) sx.stx_btime.tv_nsec / NSEC_PER_USEC;
+ else
+ a = USEC_INFINITY;
+
+ r = fgetxattrat_fake(dirfd, name, "user.crtime_usec", &le, sizeof(le), flags, &n);
+ if (r >= 0) {
+ if (n != sizeof(le))
+ r = -EIO;
+ else
+ r = parse_crtime(le, &b);
+ }
+ if (r < 0) {
+ if (a != USEC_INFINITY) {
+ *ret = a;
+ return 0;
+ }
- assert(fd >= 0);
- assert(usec);
+ return r;
+ }
- /* Until Linux gets a real concept of birthtime/creation time,
- * let's fake one with xattrs */
+ if (a != USEC_INFINITY)
+ *ret = MIN(a, b);
+ else
+ *ret = b;
- n = fgetxattr(fd, "user.crtime_usec", &le, sizeof(le));
- if (n < 0)
- return -errno;
- if (n != sizeof(le))
- return -EIO;
-
- return parse_crtime(le, usec);
+ return 0;
}
-int fd_getcrtime_at(int dirfd, const char *name, usec_t *usec, int flags) {
- le64_t le;
- ssize_t n;
-
- n = fgetxattrat_fake(dirfd, name, "user.crtime_usec", &le, sizeof(le), flags);
- if (n < 0)
- return -errno;
- if (n != sizeof(le))
- return -EIO;
-
- return parse_crtime(le, usec);
+int fd_getcrtime(int fd, usec_t *ret) {
+ return fd_getcrtime_at(fd, NULL, ret, AT_EMPTY_PATH);
}
-int path_getcrtime(const char *p, usec_t *usec) {
- le64_t le;
- ssize_t n;
-
- assert(p);
- assert(usec);
-
- n = getxattr(p, "user.crtime_usec", &le, sizeof(le));
- if (n < 0)
- return -errno;
- if (n != sizeof(le))
- return -EIO;
-
- return parse_crtime(le, usec);
+int path_getcrtime(const char *p, usec_t *ret) {
+ return fd_getcrtime_at(AT_FDCWD, p, ret, 0);
}
int fd_setcrtime(int fd, usec_t usec) {
assert(fd >= 0);
- if (usec <= 0)
+ if (IN_SET(usec, 0, USEC_INFINITY))
usec = now(CLOCK_REALTIME);
le = htole64((uint64_t) usec);
~ianmdlvl / elogind.git / blobdiff