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/*
* linux/fs/proc/mem.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <asm/page.h>
#include <asm/segment.h>
#include <asm/io.h>
/*
* mem_write isn't really a good idea right now. It needs
* to check a lot more: if the process we try to write to
* dies in the middle right now, mem_write will overwrite
* kernel memory.. This disables it altogether.
*/
#define mem_write NULL
static int mem_read(struct inode * inode, struct file * file,char * buf, int count)
{
unsigned long addr, pid, cr3;
char *tmp;
unsigned long pte, page;
int i;
if (count < 0)
return -EINVAL;
pid = inode->i_ino;
pid >>= 16;
cr3 = 0;
for (i = 1 ; i < NR_TASKS ; i++)
if (task[i] && task[i]->pid == pid) {
cr3 = task[i]->tss.cr3;
break;
}
if (!cr3)
return -EACCES;
addr = file->f_pos;
tmp = buf;
while (count > 0) {
if (current->signal & ~current->blocked)
break;
pte = *PAGE_DIR_OFFSET(cr3,addr);
if (!(pte & PAGE_PRESENT))
break;
pte &= PAGE_MASK;
pte += PAGE_PTR(addr);
page = *(unsigned long *) pte;
if (!(page & 1))
break;
page &= PAGE_MASK;
page += addr & ~PAGE_MASK;
i = PAGE_SIZE-(addr & ~PAGE_MASK);
if (i > count)
i = count;
memcpy_tofs(tmp,(void *) page,i);
addr += i;
tmp += i;
count -= i;
}
file->f_pos = addr;
return tmp-buf;
}
#ifndef mem_write
static int mem_write(struct inode * inode, struct file * file,char * buf, int count)
{
unsigned long addr, pid, cr3;
char *tmp;
unsigned long pte, page;
int i;
if (count < 0)
return -EINVAL;
addr = file->f_pos;
pid = inode->i_ino;
pid >>= 16;
cr3 = 0;
for (i = 1 ; i < NR_TASKS ; i++)
if (task[i] && task[i]->pid == pid) {
cr3 = task[i]->tss.cr3;
break;
}
if (!cr3)
return -EACCES;
tmp = buf;
while (count > 0) {
if (current->signal & ~current->blocked)
break;
pte = *PAGE_DIR_OFFSET(cr3,addr);
if (!(pte & PAGE_PRESENT))
break;
pte &= PAGE_MASK;
pte += PAGE_PTR(addr);
page = *(unsigned long *) pte;
if (!(page & PAGE_PRESENT))
break;
if (!(page & 2)) {
do_wp_page(0,addr,current,0);
continue;
}
page &= PAGE_MASK;
page += addr & ~PAGE_MASK;
i = PAGE_SIZE-(addr & ~PAGE_MASK);
if (i > count)
i = count;
memcpy_fromfs((void *) page,tmp,i);
addr += i;
tmp += i;
count -= i;
}
file->f_pos = addr;
if (tmp != buf)
return tmp-buf;
if (current->signal & ~current->blocked)
return -ERESTARTSYS;
return 0;
}
#endif
static int mem_lseek(struct inode * inode, struct file * file, off_t offset, int orig)
{
switch (orig) {
case 0:
file->f_pos = offset;
return file->f_pos;
case 1:
file->f_pos += offset;
return file->f_pos;
default:
return -EINVAL;
}
}
int
mem_mmap(struct inode * inode, struct file * file,
struct vm_area_struct * vma)
{
unsigned long *src_table, *dest_table, stmp, dtmp, cr3;
struct vm_area_struct *src_vma = 0;
int i;
/* Get the source's task information */
cr3 = 0;
for (i = 1 ; i < NR_TASKS ; i++)
if (task[i] && task[i]->pid == (inode->i_ino >> 16)) {
cr3 = task[i]->tss.cr3;
src_vma = task[i]->mm->mmap;
break;
}
if (!cr3)
return -EACCES;
/* Ensure that we have a valid source area. (Has to be mmap'ed and
have valid page information.) We can't map shared memory at the
moment because working out the vm_area_struct & nattach stuff isn't
worth it. */
stmp = vma->vm_offset;
while (stmp < vma->vm_offset + (vma->vm_end - vma->vm_start)) {
while (src_vma && stmp > src_vma->vm_end)
src_vma = src_vma->vm_next;
if (!src_vma || (src_vma->vm_flags & VM_SHM))
return -EINVAL;
src_table = PAGE_DIR_OFFSET(cr3, stmp);
if (!*src_table)
return -EINVAL;
src_table = (unsigned long *)((*src_table & PAGE_MASK) + PAGE_PTR(stmp));
if (!*src_table)
return -EINVAL;
if (stmp < src_vma->vm_start) {
if (!(src_vma->vm_flags & VM_GROWSDOWN))
return -EINVAL;
if (src_vma->vm_end - stmp > current->rlim[RLIMIT_STACK].rlim_cur)
return -EINVAL;
}
stmp += PAGE_SIZE;
}
src_vma = task[i]->mm->mmap;
stmp = vma->vm_offset;
dtmp = vma->vm_start;
while (dtmp < vma->vm_end) {
while (src_vma && stmp > src_vma->vm_end)
src_vma = src_vma->vm_next;
src_table = PAGE_DIR_OFFSET(cr3, stmp);
src_table = (unsigned long *)((*src_table & PAGE_MASK) + PAGE_PTR(stmp));
dest_table = PAGE_DIR_OFFSET(current->tss.cr3, dtmp);
if (!*dest_table) {
*dest_table = get_free_page(GFP_KERNEL);
if (!*dest_table) { oom(current); *dest_table=BAD_PAGE; }
else *dest_table |= PAGE_TABLE;
}
dest_table = (unsigned long *)((*dest_table & PAGE_MASK) + PAGE_PTR(dtmp));
if (!(*src_table & PAGE_PRESENT))
do_no_page(src_vma, stmp, PAGE_PRESENT);
if ((vma->vm_flags & VM_WRITE) && !(*src_table & PAGE_RW))
do_wp_page(src_vma, stmp, PAGE_RW | PAGE_PRESENT);
*src_table |= PAGE_DIRTY;
*dest_table = *src_table;
mem_map[MAP_NR(*src_table)]++;
stmp += PAGE_SIZE;
dtmp += PAGE_SIZE;
}
invalidate();
return 0;
}
static struct file_operations proc_mem_operations = {
mem_lseek,
mem_read,
mem_write,
NULL, /* mem_readdir */
NULL, /* mem_select */
NULL, /* mem_ioctl */
mem_mmap, /* mmap */
NULL, /* no special open code */
NULL, /* no special release code */
NULL /* can't fsync */
};
struct inode_operations proc_mem_inode_operations = {
&proc_mem_operations, /* default base directory file-ops */
NULL, /* create */
NULL, /* lookup */
NULL, /* link */
NULL, /* unlink */
NULL, /* symlink */
NULL, /* mkdir */
NULL, /* rmdir */
NULL, /* mknod */
NULL, /* rename */
NULL, /* readlink */
NULL, /* follow_link */
NULL, /* bmap */
NULL, /* truncate */
NULL /* permission */
};
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