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Added copy_vma() function.

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Sorting out return_from_fork() and kernel stack setup for the child.
This commit is contained in:
Bahadir Balban
2008-08-21 12:18:38 +03:00
parent 69db3a04c0
commit dada3e0b2c
5 changed files with 114 additions and 427 deletions
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76
tasks/mm0/src/clone.c
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@@ -7,42 +7,52 @@
#include <vm_area.h>
#include <task.h>
/*
* Copy all vmas from the given task and populate each with
* links to every object that the original vma is linked to.
* Note, that we don't copy vm objects but just the links to
* them, because vm objects are not per-process data.
*/
int copy_vmas(struct tcb *to, struct tcb *from)
{
struct vm_area *vma, new;
struct vm_area *vma, new_vma;
struct vm_obj_link *vmo_link, *new_link;
list_for_each_entry(vma, from->vm_area_list, list) {
/* Create a new vma */
new = vma_new(vma->pfn_start, vma->pfn_end - vma->pfn_start,
vma->flags, vma->file_offset);
new_vma = vma_new(vma->pfn_start, vma->pfn_end - vma->pfn_start,
vma->flags, vma->file_offset);
/*
* Populate it with links to every object that the original
* vma is linked to. Note, that we don't copy vm objects but
* just the links to them, because vm objects are not
* per-process data.
*/
/* Get the first object on the vma */
BUG_ON(list_empty(&vma->vm_obj_list));
vmo_link = list_entry(vma->vm_obj_list.next,
struct vm_obj_link, list);
do {
/* Create a new link */
new_link = vm_objlink_create();
/* Get the first object, either original file or a shadow */
if (!(vmo_link = vma_next_link(&vma->vm_obj_list, &vma->vm_obj_list))) {
printf("%s:%s: No vm object in vma!\n",
__TASKNAME__, __FUNCTION__);
BUG();
}
/* Create a new link */
new_link = vm_objlink_create();
/* Copy all fields from original link.
* E.g. if ori
/* Copy object field from original link. */
new_link->obj = vmo_link->obj;
/* Add the new link to vma in object order */
list_add_tail(&new_link->list, &new_vma->vm_obj_list);
/* Continue traversing links, doing the same copying */
} while((vmo_link = vma_next_link(&vmo_link->list,
&vma->vm_obj_list)));
/* All link copying is finished, now add the new vma to task */
list_add_tail(&vma_new->list, &to->vm_area_list);
}
return 0;
}
int copy_tcb(struct tcb *to, struct tcb *from)
{
/* Copy program segments, file descriptors, vm areas */
/* Copy program segment boundary information */
to->start = from->start;
to->end = from->end;
to->text_start = from->text_start;
@@ -62,8 +72,6 @@ int copy_tcb(struct tcb *to, struct tcb *from)
to->map_start = from->map_start;
to->map_end = from->map_end;
/* UTCB ??? */
BUG();
/* Copy all vm areas */
copy_vmas(to, from);
@@ -75,8 +83,8 @@ int copy_tcb(struct tcb *to, struct tcb *from)
int do_fork(struct tcb *parent)
{
struct task_ids ids = { .tid = TASK_ID_INVALID, .spid = parent->spid };
struct tcb *child;
struct task_ids ids = { .tid = TASK_ID_INVALID, .spid = TASK_ID_INVALID };
/*
* Allocate and copy parent pgd + all pmds to child.
@@ -95,20 +103,30 @@ int do_fork(struct tcb *parent)
/* Make all shadows in this task read-only */
vm_freeze_shadows(parent);
/* Create a new L4 thread with parent's page tables copied */
ids.spid = parent->spid;
/*
* Create a new L4 thread with parent's page tables
* kernel stack and kernel-side tcb copied
*/
child = task_create(&ids, THREAD_CREATE_COPYSPACE);
/* Copy parent tcb to child */
copy_tcb(child, parent);
/* FIXME: Need to copy parent register values to child ??? */
/* Create new utcb for child since it can't use its parent's */
child->utcb = utcb_vaddr_new();
/* Create the utcb shared memory segment available for child to shmat() */
if (IS_ERR(shm = shm_new((key_t)child->utcb, __pfn(DEFAULT_UTCB_SIZE)))) {
l4_ipc_return((int)shm);
return 0;
}
/* FIXME: We should munmap() parent's utcb page from child */
/* Notify fs0 about forked process */
vfs_send_fork(parent, child);
/* Start forked child */
l4_thread_start(child);
/* Start forked child. FIXME: Return ipc to child as well ??? */
l4_thread_control(THREAD_START, child);
/* Return back to parent */
l4_ipc_return(0);