201 lines
5.1 KiB
C
201 lines
5.1 KiB
C
/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/time.h>
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#include <sys/xattr.h>
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#include "alloc-util.h"
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#include "fd-util.h"
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#include "macro.h"
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#include "sparse-endian.h"
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#include "stdio-util.h"
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#include "time-util.h"
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#include "xattr-util.h"
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int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink) {
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char *v;
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size_t l;
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ssize_t n;
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assert(path);
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assert(name);
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assert(value);
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for (l = 100; ; l = (size_t) n + 1) {
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v = new0(char, l);
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if (!v)
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return -ENOMEM;
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if (allow_symlink)
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n = lgetxattr(path, name, v, l);
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else
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n = getxattr(path, name, v, l);
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if (n >= 0 && (size_t) n < l) {
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*value = v;
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return n;
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}
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free(v);
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if (n < 0 && errno != ERANGE)
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return -errno;
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if (allow_symlink)
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n = lgetxattr(path, name, NULL, 0);
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else
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n = getxattr(path, name, NULL, 0);
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if (n < 0)
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return -errno;
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}
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}
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int fgetxattr_malloc(int fd, const char *name, char **value) {
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char *v;
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size_t l;
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ssize_t n;
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assert(fd >= 0);
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assert(name);
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assert(value);
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for (l = 100; ; l = (size_t) n + 1) {
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v = new0(char, l);
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if (!v)
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return -ENOMEM;
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n = fgetxattr(fd, name, v, l);
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if (n >= 0 && (size_t) n < l) {
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*value = v;
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return n;
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}
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free(v);
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if (n < 0 && errno != ERANGE)
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return -errno;
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n = fgetxattr(fd, name, NULL, 0);
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if (n < 0)
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return -errno;
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}
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}
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ssize_t fgetxattrat_fake(int dirfd, const char *filename, const char *attribute, void *value, size_t size, int flags) {
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char fn[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
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_cleanup_close_ int fd = -1;
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ssize_t l;
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/* The kernel doesn't have a fgetxattrat() command, hence let's emulate one */
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fd = openat(dirfd, filename, O_CLOEXEC|O_PATH|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0));
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if (fd < 0)
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return -errno;
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xsprintf(fn, "/proc/self/fd/%i", fd);
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l = getxattr(fn, attribute, value, size);
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if (l < 0)
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return -errno;
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return l;
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}
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static int parse_crtime(le64_t le, usec_t *usec) {
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uint64_t u;
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assert(usec);
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u = le64toh(le);
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if (IN_SET(u, 0, (uint64_t) -1))
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return -EIO;
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*usec = (usec_t) u;
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return 0;
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}
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int fd_getcrtime(int fd, usec_t *usec) {
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le64_t le;
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ssize_t n;
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assert(fd >= 0);
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assert(usec);
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/* Until Linux gets a real concept of birthtime/creation time,
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* let's fake one with xattrs */
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n = fgetxattr(fd, "user.crtime_usec", &le, sizeof(le));
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if (n < 0)
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return -errno;
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if (n != sizeof(le))
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return -EIO;
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return parse_crtime(le, usec);
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}
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int fd_getcrtime_at(int dirfd, const char *name, usec_t *usec, int flags) {
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le64_t le;
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ssize_t n;
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n = fgetxattrat_fake(dirfd, name, "user.crtime_usec", &le, sizeof(le), flags);
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if (n < 0)
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return -errno;
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if (n != sizeof(le))
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return -EIO;
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return parse_crtime(le, usec);
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}
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int path_getcrtime(const char *p, usec_t *usec) {
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le64_t le;
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ssize_t n;
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assert(p);
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assert(usec);
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n = getxattr(p, "user.crtime_usec", &le, sizeof(le));
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if (n < 0)
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return -errno;
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if (n != sizeof(le))
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return -EIO;
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return parse_crtime(le, usec);
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}
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int fd_setcrtime(int fd, usec_t usec) {
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le64_t le;
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assert(fd >= 0);
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if (usec <= 0)
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usec = now(CLOCK_REALTIME);
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le = htole64((uint64_t) usec);
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if (fsetxattr(fd, "user.crtime_usec", &le, sizeof(le), 0) < 0)
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return -errno;
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return 0;
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}
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