util-lib: split xattr-related calls into xattr-util.[ch]

1 files changed, 193 insertions, 0 deletions

diff --git a/src/basic/xattr-util.c b/src/basic/xattr-util.c
new file mode 100644
index 0000000000..35fd1c1616
--- /dev/null
+++ b/src/basic/xattr-util.c
@@ -0,0 +1,193 @@
+/*-*- 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 "fd-util.h"
+#include "sparse-endian.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;
+}