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-rw-r--r--src/basic/xattr-util.c195
1 files changed, 195 insertions, 0 deletions
diff --git a/src/basic/xattr-util.c b/src/basic/xattr-util.c
new file mode 100644
index 0000000000..6abdaedc3e
--- /dev/null
+++ b/src/basic/xattr-util.c
@@ -0,0 +1,195 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ 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 <sys/xattr.h>
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "sparse-endian.h"
+#include "stdio-util.h"
+#include "util.h"
+#include "xattr-util.h"
+
+int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink) {
+ char *v;
+ size_t l;
+ ssize_t n;
+
+ assert(path);
+ assert(name);
+ assert(value);
+
+ for (l = 100; ; l = (size_t) n + 1) {
+ v = new0(char, l);
+ if (!v)
+ return -ENOMEM;
+
+ if (allow_symlink)
+ n = lgetxattr(path, name, v, l);
+ else
+ n = getxattr(path, name, v, l);
+
+ if (n >= 0 && (size_t) n < l) {
+ *value = v;
+ return n;
+ }
+
+ free(v);
+
+ if (n < 0 && errno != ERANGE)
+ return -errno;
+
+ if (allow_symlink)
+ n = lgetxattr(path, name, NULL, 0);
+ else
+ n = getxattr(path, name, NULL, 0);
+ if (n < 0)
+ return -errno;
+ }
+}
+
+int fgetxattr_malloc(int fd, const char *name, char **value) {
+ char *v;
+ size_t l;
+ ssize_t n;
+
+ assert(fd >= 0);
+ assert(name);
+ assert(value);
+
+ for (l = 100; ; l = (size_t) n + 1) {
+ v = new0(char, l);
+ if (!v)
+ return -ENOMEM;
+
+ n = fgetxattr(fd, name, v, l);
+
+ if (n >= 0 && (size_t) n < l) {
+ *value = v;
+ return n;
+ }
+
+ free(v);
+
+ if (n < 0 && errno != ERANGE)
+ return -errno;
+
+ n = fgetxattr(fd, name, NULL, 0);
+ if (n < 0)
+ return -errno;
+ }
+}
+
+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];
+ _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_RDONLY|O_CLOEXEC|O_NOCTTY|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;
+}
+
+static int parse_crtime(le64_t le, usec_t *usec) {
+ uint64_t u;
+
+ assert(usec);
+
+ u = le64toh(le);
+ if (u == 0 || u == (uint64_t) -1)
+ return -EIO;
+
+ *usec = (usec_t) u;
+ return 0;
+}
+
+int fd_getcrtime(int fd, usec_t *usec) {
+ le64_t le;
+ ssize_t n;
+
+ assert(fd >= 0);
+ assert(usec);
+
+ /* Until Linux gets a real concept of birthtime/creation time,
+ * let's fake one with xattrs */
+
+ 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);
+}
+
+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 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 fd_setcrtime(int fd, usec_t usec) {
+ le64_t le;
+
+ assert(fd >= 0);
+
+ if (usec <= 0)
+ usec = now(CLOCK_REALTIME);
+
+ le = htole64((uint64_t) usec);
+ if (fsetxattr(fd, "user.crtime_usec", &le, sizeof(le), 0) < 0)
+ return -errno;
+
+ return 0;
+}