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mm: variable length argument support

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Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly from
the old mm into the new mm.

We create the new mm before the binfmt code runs, and place the new stack at
the very top of the address space.  Once the binfmt code runs and figures out
where the stack should be, we move it downwards.

It is a bit peculiar in that we have one task with two mm's, one of which is
inactive.

[a.p.zijlstra@chello.nl: limit stack size]
Signed-off-by: Ollie Wild <aaw@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Hugh Dickins <hugh@veritas.com>
[bunk@stusta.de: unexport bprm_mm_init]
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ollie Wild
2007-07-19 01:48:16 -07:00
committed by Linus Torvalds
parent bdf4c48af2
commit b6a2fea393
15 changed files with 557 additions and 456 deletions
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65
arch/ia64/ia32/binfmt_elf32.c
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@ -195,62 +195,27 @@ ia64_elf32_init (struct pt_regs *regs)
ia32_load_state(current);
}
/*
* Undo the override of setup_arg_pages() without this ia32_setup_arg_pages()
* will suffer infinite self recursion.
*/
#undef setup_arg_pages
int
ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
{
unsigned long stack_base;
struct vm_area_struct *mpnt;
struct mm_struct *mm = current->mm;
int i, ret;
int ret;
stack_base = IA32_STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE;
mm->arg_start = bprm->p + stack_base;
bprm->p += stack_base;
if (bprm->loader)
bprm->loader += stack_base;
bprm->exec += stack_base;
mpnt = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
if (!mpnt)
return -ENOMEM;
down_write(&current->mm->mmap_sem);
{
mpnt->vm_mm = current->mm;
mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
mpnt->vm_end = IA32_STACK_TOP;
if (executable_stack == EXSTACK_ENABLE_X)
mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
else if (executable_stack == EXSTACK_DISABLE_X)
mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
else
mpnt->vm_flags = VM_STACK_FLAGS;
mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC)?
PAGE_COPY_EXEC: PAGE_COPY;
if ((ret = insert_vm_struct(current->mm, mpnt))) {
up_write(&current->mm->mmap_sem);
kmem_cache_free(vm_area_cachep, mpnt);
return ret;
}
current->mm->stack_vm = current->mm->total_vm = vma_pages(mpnt);
ret = setup_arg_pages(bprm, IA32_STACK_TOP, executable_stack);
if (!ret) {
/*
* Can't do it in ia64_elf32_init(). Needs to be done before
* calls to elf32_map()
*/
current->thread.ppl = ia32_init_pp_list();
}
for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
struct page *page = bprm->page[i];
if (page) {
bprm->page[i] = NULL;
install_arg_page(mpnt, page, stack_base);
}
stack_base += PAGE_SIZE;
}
up_write(&current->mm->mmap_sem);
/* Can't do it in ia64_elf32_init(). Needs to be done before calls to
elf32_map() */
current->thread.ppl = ia32_init_pp_list();
return 0;
return ret;
}
static void