From 9edd65c48ee75751327c6ee6d42a7009e726d667 Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Thu, 10 Nov 2022 15:14:10 +0200
Subject: initial implementation of process copying

+ Not actually working (at least fully), need to continue debugging when
  I have time.
---
 common/vmem.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

(limited to 'common/vmem.c')

diff --git a/common/vmem.c b/common/vmem.c
index 73bc672..42b4adf 100644
--- a/common/vmem.c
+++ b/common/vmem.c
@@ -8,6 +8,7 @@
 
 #include <apos/mem_regions.h>
 #include <apos/assert.h>
+#include <apos/string.h>
 #include <apos/debug.h>
 #include <apos/bits.h>
 #include <apos/vmem.h>
@@ -18,6 +19,20 @@ stat_t init_uvmem(struct tcb *t, vm_t base, vm_t top)
 	return init_region(&t->sp_r, base, top);
 }
 
+static stat_t __clone_mapped_region(struct tcb *d, struct tcb *s, struct mem_region *m)
+{
+	size_t size = 0;
+	vm_t va = alloc_fixed_region(&d->sp_r, m->start, m->end - m->start,
+			&size, m->flags);
+
+	catastrophic_assert(va == m->start);
+
+	if (copy_allocd_region(d->proc.vmem, va, size, m->flags, s))
+		return ERR_MISC;
+
+	return OK;
+}
+
 /**
  * Convenience function for freeing mapped regions.
  *
@@ -70,6 +85,21 @@ stat_t destroy_uvmem(struct tcb *t)
 	return destroy_region(&t->sp_r);
 }
 
+stat_t clone_mem_regions(struct tcb *d, struct tcb *s)
+{
+	/** @todo implement some way to only iterate used regions, this loops
+	 * through all regions which is likely a slight bit slower. */
+	struct mem_region *m = find_first_region(&s->sp_r);
+	while (m) {
+		if (is_region_used(m))
+			__clone_mapped_region(d, s, m);
+
+		m = m->next;
+	}
+
+	return OK;
+}
+
 vm_t alloc_uvmem(struct tcb *t, size_t size, vmflags_t flags)
 {
 	/* t exists and is the process tcb of the current process */
@@ -189,6 +219,34 @@ stat_t alloc_shared_wrapper(struct vmem *b, pm_t *offset, vm_t vaddr,
 	return (ret == INFO_SEFF) ? OK : ret;
 }
 
+stat_t copy_allocd_wrapper(struct vmem *b, pm_t *offset, vm_t vaddr,
+		vmflags_t flags, enum mm_order order, void *data)
+{
+	struct vmem *s = (struct vmem *)data;
+
+	pm_t paddr = 0;
+	enum mm_order v_order = 0;
+	stat_vpage(s, vaddr, &paddr, &v_order, 0);
+	/** @todo what if we could combine multiple pages into one in the new
+	 * process? */
+	if (order > v_order)
+		return INFO_TRGN;
+
+	pm_t new_page = alloc_page(order);
+	if (!new_page)
+		return INFO_TRGN;
+
+	map_vpage(b, new_page, vaddr, flags, order);
+	memcpy((void *)new_page, (void *)(paddr + *offset), order_size(order));
+
+	if (v_order > order)
+		*offset += order_size(order);
+	else
+		*offset = 0;
+
+	return OK;
+}
+
 stat_t free_uvmem_wrapper(struct vmem *b, pm_t *offset, vm_t vaddr,
                           vmflags_t flags, enum mm_order order, void *data)
 {
-- 
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