+#define SMACK_FLOOR_LABEL "_"
+#define SMACK_STAR_LABEL "*"
+
+bool mac_smack_use(void) {
+#ifdef HAVE_SMACK
+ static int cached_use = -1;
+
+ if (cached_use < 0)
+ cached_use = access("/sys/fs/smackfs/", F_OK) >= 0;
+
+ return cached_use;
+#else
+ return false;
+#endif
+}
+
+int mac_smack_apply(const char *path, const char *label) {
+ int r = 0;
+
+ assert(path);
+
+#ifdef HAVE_SMACK
+ if (!mac_smack_use())
+ return 0;
+
+ if (label)
+ r = lsetxattr(path, "security.SMACK64", label, strlen(label), 0);
+ else
+ r = lremovexattr(path, "security.SMACK64");
+ if (r < 0)
+ return -errno;
+#endif
+
+ return r;
+}
+
+int mac_smack_apply_fd(int fd, const char *label) {
+ int r = 0;
+
+ assert(fd >= 0);
+
+#ifdef HAVE_SMACK
+ if (!mac_smack_use())
+ return 0;
+
+ if (label)
+ r = fsetxattr(fd, "security.SMACK64", label, strlen(label), 0);
+ else
+ r = fremovexattr(fd, "security.SMACK64");
+ if (r < 0)
+ return -errno;
+#endif
+
+ return r;
+}
+
+int mac_smack_apply_ip_out_fd(int fd, const char *label) {
+ int r = 0;
+
+ assert(fd >= 0);
+
+#ifdef HAVE_SMACK
+ if (!mac_smack_use())
+ return 0;
+
+ if (label)
+ r = fsetxattr(fd, "security.SMACK64IPOUT", label, strlen(label), 0);
+ else
+ r = fremovexattr(fd, "security.SMACK64IPOUT");
+ if (r < 0)
+ return -errno;
+#endif
+
+ return r;
+}
+
+int mac_smack_apply_ip_in_fd(int fd, const char *label) {
+ int r = 0;
+
+ assert(fd >= 0);
+
+#ifdef HAVE_SMACK
+ if (!mac_smack_use())
+ return 0;
+
+ if (label)
+ r = fsetxattr(fd, "security.SMACK64IPIN", label, strlen(label), 0);
+ else
+ r = fremovexattr(fd, "security.SMACK64IPIN");
+ if (r < 0)
+ return -errno;
+#endif
+
+ return r;
+}
+
+int mac_smack_apply_pid(pid_t pid, const char *label) {
+
+#ifdef HAVE_SMACK
+ const char *p;
+#endif
+ int r = 0;
+
+ assert(label);
+
+#ifdef HAVE_SMACK
+ if (!mac_smack_use())
+ return 0;
+
+ p = procfs_file_alloca(pid, "attr/current");
+ r = write_string_file(p, label);
+ if (r < 0)
+ return r;
+#endif
+
+ return r;
+}
+
+int mac_smack_fix(const char *path, bool ignore_enoent, bool ignore_erofs) {
+
+#ifdef HAVE_SMACK
+ struct stat st;
+#endif
+ int r = 0;
+
+ assert(path);
+
+#ifdef HAVE_SMACK
+ if (!mac_smack_use())
+ return 0;
+
+ /*
+ * Path must be in /dev and must exist
+ */
+ if (!path_startswith(path, "/dev"))
+ return 0;
+
+ r = lstat(path, &st);
+ if (r >= 0) {
+ const char *label;
+
+ /*
+ * Label directories and character devices "*".
+ * Label symlinks "_".
+ * Don't change anything else.
+ */
+
+ if (S_ISDIR(st.st_mode))
+ label = SMACK_STAR_LABEL;
+ else if (S_ISLNK(st.st_mode))
+ label = SMACK_FLOOR_LABEL;
+ else if (S_ISCHR(st.st_mode))
+ label = SMACK_STAR_LABEL;
+ else
+ return 0;
+
+ r = lsetxattr(path, "security.SMACK64", label, strlen(label), 0);
+
+ /* If the FS doesn't support labels, then exit without warning */
+ if (r < 0 && errno == EOPNOTSUPP)
+ return 0;
+ }