From 949c43436e1c229e50a802e15a43642f85fff365 Mon Sep 17 00:00:00 2001
From: Alex Kotov <kotovalexarian@gmail.com>
Date: Tue, 11 Jan 2022 14:10:16 +0500
Subject: [PATCH] Fix struct KernAux_Multiboot2_Tag_BootCmdLine

---
 include/kernaux/multiboot2.h | 5 +++--
 src/multiboot2/helpers.c     | 2 +-
 src/multiboot2/is_valid.c    | 2 +-
 src/multiboot2/print.c       | 4 +++-
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/kernaux/multiboot2.h b/include/kernaux/multiboot2.h
index bebc2b5..3dca995 100644
--- a/include/kernaux/multiboot2.h
+++ b/include/kernaux/multiboot2.h
@@ -5,10 +5,13 @@
 extern "C" {
 #endif
 
+#include <stdint.h>
 #include <stdbool.h>
 
 #define KERNAUX_MULTIBOOT2_MAGIC 0x36d76289
 
+#define KERNAUX_MULTIBOOT2_TAG_DATA(tag) (((uint8_t*)(tag)) + sizeof(*(tag)))
+
 /****************
  * Common types *
  ****************/
@@ -67,8 +70,6 @@ struct KernAux_Multiboot2_Tag_BootCmdLine {
     // type = 1
     // size = ?
     struct KernAux_Multiboot2_TagBase base;
-
-    char cmdline[];
 }
 __attribute__((packed));
 
diff --git a/src/multiboot2/helpers.c b/src/multiboot2/helpers.c
index ec88fe9..df753ec 100644
--- a/src/multiboot2/helpers.c
+++ b/src/multiboot2/helpers.c
@@ -63,5 +63,5 @@ const char *KernAux_Multiboot2_boot_cmd_line(
 
     if (!tag) return NULL;
 
-    return tag->cmdline;
+    return (char*)KERNAUX_MULTIBOOT2_TAG_DATA(tag);
 }
diff --git a/src/multiboot2/is_valid.c b/src/multiboot2/is_valid.c
index 7caebf1..e2d418f 100644
--- a/src/multiboot2/is_valid.c
+++ b/src/multiboot2/is_valid.c
@@ -162,7 +162,7 @@ bool KernAux_Multiboot2_Tag_BootCmdLine_is_valid(
     size_t index = 1;
 
     for (
-        const char *ptr = tag->cmdline;
+        const char *ptr = (char*)KERNAUX_MULTIBOOT2_TAG_DATA(tag);
         *ptr && index < tag->base.size;
         ++ptr
     ) {
diff --git a/src/multiboot2/print.c b/src/multiboot2/print.c
index d1abe3e..c000681 100644
--- a/src/multiboot2/print.c
+++ b/src/multiboot2/print.c
@@ -120,7 +120,9 @@ void KernAux_Multiboot2_TagBase_print(
     case KERNAUX_MULTIBOOT2_TAGTYPE_BOOT_CMD_LINE:
         printf(
             "  cmdline: %s\n",
-            ((struct KernAux_Multiboot2_Tag_BootCmdLine*)tag_base)->cmdline
+            KERNAUX_MULTIBOOT2_TAG_DATA(
+                (struct KernAux_Multiboot2_Tag_BootCmdLine*)tag_base
+            )
         );
         break;
     case KERNAUX_MULTIBOOT2_TAGTYPE_BOOT_LOADER_NAME: