diff --git a/arch/um/include/user.h b/arch/um/include/user.h
index 57ee9e26122843869bb185432ef8bb3260ac739a..0f865ef46918190d528f556506ca9439d75da175 100644
--- a/arch/um/include/user.h
+++ b/arch/um/include/user.h
@@ -14,7 +14,9 @@ extern void *um_kmalloc_atomic(int size);
 extern void kfree(void *ptr);
 extern int in_aton(char *str);
 extern int open_gdb_chan(void);
-extern int strlcpy(char *, const char *, int);
+/* These use size_t, however unsigned long is correct on both i386 and x86_64. */
+extern unsigned long strlcpy(char *, const char *, unsigned long);
+extern unsigned long strlcat(char *, const char *, unsigned long);
 extern void *um_vmalloc(int size);
 extern void vfree(void *ptr);
 
diff --git a/arch/um/kernel/umid.c b/arch/um/kernel/umid.c
index 251d277fff2a39fa19a5157a8cae713e182e9982..0b21d59ba0cdcdf3555e2f57fa2f8bd2a254c6b0 100644
--- a/arch/um/kernel/umid.c
+++ b/arch/um/kernel/umid.c
@@ -237,16 +237,13 @@ static int __init make_uml_dir(void)
 		strlcpy(dir, home, sizeof(dir));
 		uml_dir++;
 	}
+	strlcat(dir, uml_dir, sizeof(dir));
 	len = strlen(dir);
-	strncat(dir, uml_dir, sizeof(dir) - len);
-	len = strlen(dir);
-	if((len > 0) && (len < sizeof(dir) - 1) && (dir[len - 1] != '/')){
-		dir[len] = '/';
-		dir[len + 1] = '\0';
-	}
+	if (len > 0 && dir[len - 1] != '/')
+		strlcat(dir, "/", sizeof(dir));
 
 	uml_dir = malloc(strlen(dir) + 1);
-	if(uml_dir == NULL){
+	if (uml_dir == NULL) {
 		printf("make_uml_dir : malloc failed, errno = %d\n", errno);
 		exit(1);
 	}