From e793e45854b0434c3a95305122bf4754e894be55 Mon Sep 17 00:00:00 2001
From: Ruslan Isaev <ubijca16@gmail.com>
Date: Mon, 7 Jul 2025 00:19:35 +0300
Subject: [PATCH] syscalls: continue working on fork syscall

---
 Makefile               |  2 +-
 src/mm/paging.c        | 38 +++++++++++++++++++++++++++++++-------
 src/tasking/syscalls.c |  6 +++++-
 3 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/Makefile b/Makefile
index 85a8344..dd2518b 100644
--- a/Makefile
+++ b/Makefile
@@ -57,7 +57,7 @@ debug:
 	qemu-system-i386 -s -S -kernel katauos.bin -monitor stdio
 
 debug2:
-	qemu-system-i386 -s -S -drive file=boot.iso,media=disk,format=raw -monitor stdio
+	qemu-system-i386 -s -S -drive file=boot.iso,media=disk,format=raw -m 4096M -monitor stdio
 
 test-bochs:
 	bochs -f bochsrc
diff --git a/src/mm/paging.c b/src/mm/paging.c
index 626e5bc..d08b8f9 100644
--- a/src/mm/paging.c
+++ b/src/mm/paging.c
@@ -1,6 +1,8 @@
 #include "../include/paging.h"
 #include <stdint.h>
 #include "../include/string.h"
+#include "../include/kheap.h"
+#include "../include/liballoc.h"
 
 uint32_t *kpage_dir;
 
@@ -123,6 +125,11 @@ uint32_t phys_to_virt(uint32_t phys)
     return phys+0xC0000000;
 }
 
+void* phys_to_virt2(void* phys)
+{
+    return phys+0xC0000000;
+}
+
 uint32_t* create_page_dir()
 {
     void* ppp = alloc_page();
@@ -190,14 +197,19 @@ void destroy_page_dir(uint32_t* page_dir_virt) {
     free_page((void*)virt_to_phys(page_dir_virt));
 }
 
+static void* scratch_src = (void*)0xE1000000;
+static void* scratch_dst = (void*)0xE1001000;
+
 uint32_t* copy_page_dir(uint32_t* page_dir_virt)
 {
     if(page_dir_virt == NULL)
         return 0;
+
+    debug_log("====%X %X\n", scratch_dst, scratch_src);
     
     uint32_t* new_pagedir = create_page_dir();
     
-    for(int i = 0; i < 768; i++)
+    for(int i = 1; i < 768; i++)
     {
         uint32_t pde = page_dir_virt[i];
 
@@ -208,6 +220,7 @@ uint32_t* copy_page_dir(uint32_t* page_dir_virt)
             if(new_page_table == NULL) {
                 return NULL;
             }
+            uint32_t* new_page_table_virt = (uint32_t*)phys_to_virt((uint32_t)new_page_table);
             
             // Get original page table (physical address from PDE)
             uint32_t* orig_page_table = (uint32_t*)phys_to_virt(pde & ~0xFFF);
@@ -225,14 +238,24 @@ uint32_t* copy_page_dir(uint32_t* page_dir_virt)
 
                     void* orig_phys_page = (void*)(pte & ~0xFFF);
 
-                    debug_log("copying %X to %X...", orig_phys_page, new_phys_page);
-                    memcpy(new_phys_page, orig_phys_page, PAGE_SIZE);
-                    debug_log("done\n");
-                    new_page_table[j] = (uint32_t)new_phys_page | (pte & 0xFFF);
+                    map_page(orig_phys_page, scratch_src, PAGE_PRESENT | PAGE_RW);
+                    map_page(new_phys_page, scratch_dst, PAGE_PRESENT | PAGE_RW);
+
+                    //debug_log("copying %X to %X...", orig_phys_page, new_phys_page);
+                    //memcpy(new_phys_page, orig_phys_page, PAGE_SIZE);
+                    //memcpy(new_virt_page, orig_virt_page, PAGE_SIZE);
+
+                    memcpy(scratch_dst, scratch_src, PAGE_SIZE);
+
+                    unmap_page(scratch_dst);
+                    unmap_page(scratch_src);
+
+                    //debug_log("done\n");
+                    new_page_table_virt[j] = (uint32_t)new_phys_page | (pte & 0xFFF);
                 }
                 else
                 {
-                    new_page_table[j] = pte;
+                    new_page_table_virt[j] = pte;
                 }
             }
             
@@ -246,5 +269,6 @@ uint32_t* copy_page_dir(uint32_t* page_dir_virt)
         }
     }
     debug_log("ENDENDENDEND\n");
-    return new_pagedir;
+
+    return new_pagedir - 0xC0000000;
 }
\ No newline at end of file
diff --git a/src/tasking/syscalls.c b/src/tasking/syscalls.c
index 0c9bf87..acf35da 100644
--- a/src/tasking/syscalls.c
+++ b/src/tasking/syscalls.c
@@ -62,7 +62,11 @@ int sys_fork(TrapFrame *tf)
 {
     debug_log("FORKFORKFORKFORK\n");
 
-    uint32_t* new_pd = copy_page_dir(current->pagedir);
+    uint32_t* new_pd = copy_page_dir(current->pagedir) - 0xC0000000;
+    debug_log("got this shit done hehe\n");
+
+    set_page_dir((uint32_t)new_pd - 0xC0000000);
+    while(1){}
 
     Process* child = task_create(0, 0, 3, new_pd);