From cde3702132ae0c91a5a2552fb080de40ceef9aff Mon Sep 17 00:00:00 2001
From: 0x35c <>
Date: Sun, 30 Nov 2025 13:32:24 +0100
Subject: [PATCH] feature: fork() (to be tested)

---
 headers/alloc.h                       |  6 +-
 headers/memory.h                      |  9 +--
 headers/process.h                     |  2 +-
 src/drivers/clock.c                   |  2 +-
 src/kernel.c                          |  9 +--
 src/kpanic.c                          |  2 +-
 src/memory/{virt => user}/allocator.c |  2 +-
 src/memory/{virt => user}/info.c      |  2 +-
 src/memory/{virt => user}/page.c      |  4 +-
 src/memory/{virt => user}/vfree.c     |  4 +-
 src/memory/{virt => user}/vmalloc.c   |  6 +-
 src/memory/{virt => user}/vrealloc.c  |  8 +--
 src/memory/{virt => user}/vsize.c     |  0
 src/multitasking/fork.c               | 85 +++++++++++++++++++++++++--
 src/multitasking/thread.c             |  6 +-
 src/shell/commands/heap_cmd.c         |  2 +-
 16 files changed, 113 insertions(+), 36 deletions(-)
 rename src/memory/{virt => user}/allocator.c (96%)
 rename src/memory/{virt => user}/info.c (98%)
 rename src/memory/{virt => user}/page.c (94%)
 rename src/memory/{virt => user}/vfree.c (97%)
 rename src/memory/{virt => user}/vmalloc.c (96%)
 rename src/memory/{virt => user}/vrealloc.c (89%)
 rename src/memory/{virt => user}/vsize.c (100%)

diff --git a/headers/alloc.h b/headers/alloc.h
index 2a852e4..ac52a06 100644
--- a/headers/alloc.h
+++ b/headers/alloc.h
@@ -75,10 +75,10 @@ int new_vzone(block_type_t type, size_t size);
 int new_kzone(block_type_t type, size_t size);
 /*----------------------------*/
 
-void *vmalloc(size_t size);
-void vfree(void *ptr);
+void *umalloc(size_t size);
+void ufree(void *ptr);
 void *vrealloc(void *ptr, size_t size);
-void show_valloc_mem(void);
+void show_ualloc_mem(void);
 size_t vsize(void *virt_addr);
 void *kmalloc(size_t size);
 void kfree(void *ptr);
diff --git a/headers/memory.h b/headers/memory.h
index 5a4686d..5b81b42 100644
--- a/headers/memory.h
+++ b/headers/memory.h
@@ -29,7 +29,8 @@
 #define PDE_MULTIBOOT   1020
 
 #define GET_PTE(pd_index, pt_index)                                            \
-	((uint32_t *)(VIRT_PT_BASE + ((uint32_t) pd_index) * 4096 + ((uint32_t) pt_index) * 4))
+	((uint32_t *)(VIRT_PT_BASE + ((uint32_t)pd_index) * 4096 +             \
+	              ((uint32_t)pt_index) * 4))
 
 #define PTE2VA(pd_index, pt_index)                                             \
 	((uint32_t *)((((uint32_t)pd_index * 1024) + (uint32_t)pt_index) *     \
@@ -74,6 +75,6 @@ void init_memory(void);
 void *alloc_frame(void);
 int free_frame(void *frame_ptr);
 void *kalloc_pages(size_t nb_pages);
-void *valloc_pages(size_t nb_pages);
-int kfree_pages(void *page_ptr, size_t size);
-int vfree_pages(void *page_ptr, size_t size);
+void *ualloc_pages(size_t nb_pages);
+int kfree_pages(void *page_ptr, size_t nb_pages);
+int ufree_pages(void *page_ptr, size_t nb_pages);
diff --git a/headers/process.h b/headers/process.h
index b2dc0b9..4330783 100644
--- a/headers/process.h
+++ b/headers/process.h
@@ -28,5 +28,5 @@ struct pcb {
 
 void switch_process(struct pcb *next_pcb);
 struct pcb *create_process(uid_t uid);
-// int8_t create_kernel_process(void);
 void remove_process(struct pcb *pcb);
+pid_t fork(void);
diff --git a/src/drivers/clock.c b/src/drivers/clock.c
index 3ba1213..e85ed13 100644
--- a/src/drivers/clock.c
+++ b/src/drivers/clock.c
@@ -40,7 +40,7 @@ static void clock_handler(struct registers *regs)
 {
 	scheduler_counter++;
 	sleep_counter--;
-	if (scheduler_counter % 100 == 0)
+	if (scheduler_counter % 30 == 0)
 		scheduler((uint32_t *)regs);
 }
 
diff --git a/src/kernel.c b/src/kernel.c
index 03b9499..2100145 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -33,9 +33,11 @@
 
 static void uwu(void)
 {
+	pid_t pid = fork();
+	kprintf("pid: %d\n", pid);
 	while (1) {
 		// sleep(1000);
-		kprintf("uwu\n");
+		// kprintf("%d\n", current_pcb->pid);
 	}
 }
 
@@ -55,9 +57,8 @@ void kernel_main(multiboot_info_t *mbd, uint32_t magic)
 	load_drivers();
 	terminal_initialize();
 	create_process(1);
-	create_thread(current_pcb, shell_init);
-	create_process(2);
-	create_thread(current_pcb->next, uwu);
+	// create_thread(current_pcb, shell_init);
+	create_thread(current_pcb, uwu);
 	toris();
 	while (true)
 		;
diff --git a/src/kpanic.c b/src/kpanic.c
index a75759f..758924e 100644
--- a/src/kpanic.c
+++ b/src/kpanic.c
@@ -27,7 +27,7 @@ __attribute__((noreturn)) void kpanic(const char *format, ...)
 	kprintf("fault at address: %p\n", faulting_address);
 	// for (int i = 16; i < 32; i++)
 	// 	kprintf("%p\n", page_table1[i]);
-	// show_valloc_mem();
+	// show_ualloc_mem();
 	/* kprintf("\n\n"); */
 	/* print_stack(); */
 	/* kprintf("\n\n"); */
diff --git a/src/memory/virt/allocator.c b/src/memory/user/allocator.c
similarity index 96%
rename from src/memory/virt/allocator.c
rename to src/memory/user/allocator.c
index 18adbfe..fbc16b4 100644
--- a/src/memory/virt/allocator.c
+++ b/src/memory/user/allocator.c
@@ -51,7 +51,7 @@ static void new_block(Zone *zone, uint32_t zone_size)
 int new_vzone(block_type_t type, uint32_t size)
 {
 	// assert(current_task->pid);
-	void *heap = valloc_pages(CEIL(size, PAGE_SIZE));
+	void *heap = ualloc_pages(CEIL(size, PAGE_SIZE));
 	if (heap == NULL) {
 		kprintf(KERN_ERR "error: alloc_pages failed\n");
 		return (-1);
diff --git a/src/memory/virt/info.c b/src/memory/user/info.c
similarity index 98%
rename from src/memory/virt/info.c
rename to src/memory/user/info.c
index 885e87c..ab58498 100644
--- a/src/memory/virt/info.c
+++ b/src/memory/user/info.c
@@ -5,7 +5,7 @@
 // FULL_INFO is to display (or not) both used and unused blocks
 #define FULL_INFO 1
 
-void show_valloc_mem(void)
+void show_ualloc_mem(void)
 {
 	char *const zones_name[3] = {"TINY", "SMALL", "LARGE"};
 	uint32_t total_size = 0;
diff --git a/src/memory/virt/page.c b/src/memory/user/page.c
similarity index 94%
rename from src/memory/virt/page.c
rename to src/memory/user/page.c
index 747148c..1f250db 100644
--- a/src/memory/virt/page.c
+++ b/src/memory/user/page.c
@@ -40,7 +40,7 @@ static uint32_t *find_next_block(size_t nb_pages)
 	return NULL;
 }
 
-void *valloc_pages(size_t nb_pages)
+void *ualloc_pages(size_t nb_pages)
 {
 	uint32_t *start = find_next_block(nb_pages);
 	if (!start)
@@ -60,7 +60,7 @@ void *valloc_pages(size_t nb_pages)
 	return PTE2VA(page_index / 1024, page_index % 1024);
 }
 
-int vfree_pages(void *page_ptr, size_t nb_pages)
+int ufree_pages(void *page_ptr, size_t nb_pages)
 {
 	const uint32_t page_addr = (uint32_t)page_ptr;
 	if (page_addr % PAGE_SIZE) {
diff --git a/src/memory/virt/vfree.c b/src/memory/user/vfree.c
similarity index 97%
rename from src/memory/virt/vfree.c
rename to src/memory/user/vfree.c
index 36bff8c..848ba2b 100644
--- a/src/memory/virt/vfree.c
+++ b/src/memory/user/vfree.c
@@ -47,7 +47,7 @@ static int unmap_zone(Zone *zone)
 	if (right)
 		right->prev = left;
 unmap:
-	err = vfree_pages((void *)zone, zone->size);
+	err = ufree_pages((void *)zone, zone->size);
 	if (err)
 		kprintf(KERN_ERR "error: munmap failed\n");
 	return (err);
@@ -94,7 +94,7 @@ static int add_available(Block *available, Block *merged)
  * newly merged block
  * Finally, we add the block to the list of available blocks
  */
-void vfree(void *ptr)
+void ufree(void *ptr)
 {
 	if (ptr == NULL)
 		return;
diff --git a/src/memory/virt/vmalloc.c b/src/memory/user/vmalloc.c
similarity index 96%
rename from src/memory/virt/vmalloc.c
rename to src/memory/user/vmalloc.c
index 0cc2661..b75b5d1 100644
--- a/src/memory/virt/vmalloc.c
+++ b/src/memory/user/vmalloc.c
@@ -33,7 +33,7 @@ static Block *find_block(Zone *head, uint32_t size)
  * After the allocation, this will become
  * ... -> [5] -> [new] -> [6] -> ...
  *
- * For an example of [5].size = 32 and requiring a vmalloc of 10
+ * For an example of [5].size = 32 and requiring a umalloc of 10
  * Let's say the metadata takes a size of 2:
  * ... -> [metadata][data][remaining size] -> [6]
  *            ^        ^         ^
@@ -126,12 +126,12 @@ static void save_block(Zone *head, Block *block, Zone *zone)
  *
  * ptr: returns the aligned pointer of the block (after the metadata)
  */
-void *vmalloc(uint32_t size)
+void *umalloc(uint32_t size)
 {
 	void *ptr = NULL;
 
 	if (size == 0) {
-		kprintf(KERN_WARNING "vmalloc: can't vmalloc(0)\n");
+		kprintf(KERN_WARNING "umalloc: can't umalloc(0)\n");
 		return NULL;
 	}
 
diff --git a/src/memory/virt/vrealloc.c b/src/memory/user/vrealloc.c
similarity index 89%
rename from src/memory/virt/vrealloc.c
rename to src/memory/user/vrealloc.c
index 026115d..d55d98b 100644
--- a/src/memory/virt/vrealloc.c
+++ b/src/memory/user/vrealloc.c
@@ -2,9 +2,9 @@
 #include "string.h"
 #include <stdint.h>
 
-// Prototype for kfree and vmalloc
+// Prototype for kfree and umalloc
 void kfree(void *ptr);
-void *vmalloc(uint32_t size);
+void *umalloc(uint32_t size);
 
 /*
  * ptr: block to resize (undefined behavior if invalid)
@@ -28,10 +28,10 @@ void *vrealloc(void *ptr, uint32_t size)
 		block->sub_size = size;
 		return (ptr);
 	}
-	new_ptr = vmalloc(size);
+	new_ptr = umalloc(size);
 	if (new_ptr == NULL)
 		return NULL;
 	memmove(new_ptr, ptr, block->size);
-	vfree(ptr);
+	ufree(ptr);
 	return (new_ptr);
 }
diff --git a/src/memory/virt/vsize.c b/src/memory/user/vsize.c
similarity index 100%
rename from src/memory/virt/vsize.c
rename to src/memory/user/vsize.c
diff --git a/src/multitasking/fork.c b/src/multitasking/fork.c
index 17acd0f..1c453b0 100644
--- a/src/multitasking/fork.c
+++ b/src/multitasking/fork.c
@@ -6,7 +6,7 @@
 
 static struct tcb *thread_clone(struct tcb *thread)
 {
-	struct tcb *new_tcb = vmalloc(sizeof(struct tcb));
+	struct tcb *new_tcb = umalloc(sizeof(struct tcb));
 	if (!new_tcb)
 		return NULL;
 	new_tcb->tid = thread->tid;
@@ -19,20 +19,95 @@ static struct tcb *thread_clone(struct tcb *thread)
 	return new_tcb;
 }
 
+static void free_pts(void)
+{
+	for (size_t i = USER_PT_END / 2; PD[i]; i++) {
+		uint32_t *pt = PTE2VA(1023, i);
+		for (size_t j = 0; j < 1024; j++)
+			if (pt[j])
+				ufree_pages(PTE2VA(i, j), 1);
+		ufree_pages(pt, 1);
+	}
+}
+
+static int copy_pt(uint32_t *pt_src, uint32_t *pt_dest, size_t pd_index)
+{
+	for (size_t i = 0; i < 1024; i++) {
+		if (pt_src[i]) {
+			pt_dest[i] = (uint32_t)alloc_frame() | INIT_FLAGS;
+			if (pt_dest[i] == INIT_FLAGS) {
+				for (size_t j = 0; j < i; j++)
+					free_frame(
+					    (void *)(pt_dest[j] & PAGE_MASK));
+				return -1;
+			}
+			void *src_page = PTE2VA(pd_index, i);
+			void *dest_page = PTE2VA(pd_index + USER_PT_END / 2, i);
+			memcpy(dest_page, src_page, PAGE_SIZE);
+		}
+	}
+	return 0;
+}
+
+static int deep_copy(struct pcb *new_pcb)
+{
+	if (PD[USER_PT_END / 2])
+		return -2;
+	size_t i;
+	for (i = USER_PT_START; PD[i]; i++) {
+		void *new_pt = alloc_frame();
+		if (!new_pt) {
+			free_pts();
+			return -1;
+		}
+		if (!copy_pt(PTE2VA(1023, i), new_pt, i)) {
+			free_pts();
+			return -1;
+		}
+		new_pcb->heap[i] = (uint32_t)new_pt | INIT_FLAGS;
+	}
+	bzero(PD + USER_PT_END / 2, i * sizeof(uint32_t));
+	return 0;
+}
+
 pid_t fork(void)
 {
 	struct pcb *new_pcb = create_process(current_pcb->uid);
 	if (!new_pcb)
 		return -1;
-	struct list *new_node = vmalloc(sizeof(struct list));
+	struct list *new_node = kmalloc(sizeof(struct list));
 	if (!new_node) {
 		remove_process(new_pcb);
 		return -1;
 	}
 	new_pcb->daddy = current_pcb;
 	lst_add_back(&new_pcb->children, new_node);
-	// loop on threads clone
-	thread_clone(current_pcb->thread_list->content);
 
-	return new_pcb->pid;
+	if (deep_copy(new_pcb) < 0)
+		goto error;
+	struct list *e;
+	struct list *prev = NULL;
+	for (struct list *it = current_pcb->thread_list; it; it = it->next) {
+		e = kmalloc(sizeof(struct list));
+		if (!e)
+			goto error;
+		if (prev)
+			prev->next = e;
+		else
+			new_pcb->thread_list = e;
+		struct tcb *new_content = kmalloc(sizeof(struct tcb));
+		if (!new_content) {
+			kfree(e);
+			goto error;
+		}
+		memcpy(it->content, new_content, sizeof(struct tcb));
+		new_content->process = new_pcb;
+		e->next = NULL;
+		prev = e;
+	}
+
+	return current_pcb == new_pcb ? 0 : new_pcb->pid;
+error:
+	remove_process(new_pcb);
+	return -1;
 }
diff --git a/src/multitasking/thread.c b/src/multitasking/thread.c
index 6647cec..a7afba3 100644
--- a/src/multitasking/thread.c
+++ b/src/multitasking/thread.c
@@ -18,9 +18,9 @@ struct tcb *create_thread(struct pcb *process, void (*entry)(void))
 
 	memcpy(PD, process->heap,
 	       (USER_PT_END - USER_PT_START) * sizeof(uint32_t));
-	new_tcb->esp0 = valloc_pages(CEIL(STACK_SIZE, PAGE_SIZE));
+	new_tcb->esp0 = ualloc_pages(CEIL(STACK_SIZE, PAGE_SIZE));
 	if (!new_tcb->esp0) {
-		vfree(new_tcb);
+		ufree(new_tcb);
 		return NULL;
 	}
 	memcpy(process->heap, PD,
@@ -54,7 +54,7 @@ struct tcb *create_thread(struct pcb *process, void (*entry)(void))
 	struct list *new_node = kmalloc(sizeof(struct list));
 	if (!new_node) {
 		kfree_pages(new_tcb->esp0, STACK_SIZE);
-		vfree(new_tcb);
+		ufree(new_tcb);
 		return NULL;
 	}
 	new_node->content = new_tcb;
diff --git a/src/shell/commands/heap_cmd.c b/src/shell/commands/heap_cmd.c
index 14a7c61..5e09577 100644
--- a/src/shell/commands/heap_cmd.c
+++ b/src/shell/commands/heap_cmd.c
@@ -5,5 +5,5 @@
 void heap_cmd(char *arg)
 {
 	(void)arg;
-	show_valloc_mem();
+	show_ualloc_mem();
 }