PAL.C.T MINI SHELL
/*
* The kernel's access_process_vm is not exported in kernel.org kernels, although
* some distros export it on some architectures. To workaround this inconsistency,
* we copied and pasted it here. Fortunately, everything it calls is exported.
*/
#include <linux/pagemap.h>
#include <asm/cacheflush.h>
static int
__access_process_vm_ (struct task_struct *tsk, unsigned long addr, void *buf,
int len, int write,
void (*writer) (struct vm_area_struct * vma,
struct page * page, unsigned long vaddr,
void *dst, void *src, int len),
void (*reader) (struct vm_area_struct * vma,
struct page * page, unsigned long vaddr,
void *dst, void *src, int len))
{
struct mm_struct *mm;
struct vm_area_struct *vma;
struct page *page;
void *old_buf = buf;
mm = get_task_mm (tsk);
if (!mm)
return 0;
down_read (&mm->mmap_sem);
/* ignore errors, just check how much was successfully transferred */
while (len)
{
int bytes, ret, offset;
void *maddr;
ret = get_user_pages (tsk, mm, addr, 1, write, 1, &page, &vma);
if (ret <= 0)
break;
bytes = len;
offset = addr & (PAGE_SIZE - 1);
if (bytes > PAGE_SIZE - offset)
bytes = PAGE_SIZE - offset;
maddr = kmap (page);
if (write)
{
writer (vma, page, addr, maddr + offset, buf, bytes);
set_page_dirty_lock (page);
}
else
{
reader (vma, page, addr, buf, maddr + offset, bytes);
}
kunmap (page);
page_cache_release (page);
len -= bytes;
buf += bytes;
addr += bytes;
}
up_read (&mm->mmap_sem);
mmput (mm);
return buf - old_buf;
}
static void
copy_to_user_page_ (struct vm_area_struct *vma, struct page *page,
unsigned long vaddr, void *dst, void *src, int len)
{
copy_to_user_page (vma, page, vaddr, dst, src, len);
}
static void
copy_from_user_page_ (struct vm_area_struct *vma, struct page *page,
unsigned long vaddr, void *dst, void *src, int len)
{
copy_from_user_page (vma, page, vaddr, dst, src, len);
}
static int
__access_process_vm (struct task_struct *tsk, unsigned long addr, void *buf,
int len, int write)
{
return __access_process_vm_ (tsk, addr, buf, len, write, copy_to_user_page_,
copy_from_user_page_);
}
/* This simpler version does not flush the caches. */
static void
copy_to_user_page_noflush (struct vm_area_struct *vma, struct page *page,
unsigned long vaddr, void *dst, void *src, int len)
{
memcpy (dst, src, len);
}
static void
copy_from_user_page_noflush (struct vm_area_struct *vma, struct page *page,
unsigned long vaddr, void *dst, void *src,
int len)
{
memcpy (dst, src, len);
}
static int
__access_process_vm_noflush (struct task_struct *tsk, unsigned long addr,
void *buf, int len, int write)
{
return __access_process_vm_ (tsk, addr, buf, len, write,
copy_to_user_page_noflush,
copy_from_user_page_noflush);
}
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