171 lines
3.4 KiB
C
171 lines
3.4 KiB
C
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/*
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* linux/fs/proc/mem.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <asm/segment.h>
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#include <asm/io.h>
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/*
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* mem_write isn't really a good idea right now. It needs
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* to check a lot more: if the process we try to write to
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* dies in the middle right now, mem_write will overwrite
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* kernel memory.. This disables it altogether.
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*/
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#define mem_write NULL
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static int mem_read(struct inode * inode, struct file * file,char * buf, int count)
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{
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unsigned long addr, pid, cr3;
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char *tmp;
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unsigned long pte, page;
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int i;
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if (count < 0)
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return -EINVAL;
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pid = inode->i_ino;
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pid >>= 16;
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cr3 = 0;
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for (i = 1 ; i < NR_TASKS ; i++)
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if (task[i] && task[i]->pid == pid) {
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cr3 = task[i]->tss.cr3;
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break;
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}
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if (!cr3)
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return -EACCES;
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addr = file->f_pos;
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tmp = buf;
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while (count > 0) {
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if (current->signal & ~current->blocked)
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break;
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pte = *PAGE_DIR_OFFSET(cr3,addr);
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if (!(pte & PAGE_PRESENT))
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break;
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pte &= PAGE_MASK;
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pte += PAGE_PTR(addr);
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page = *(unsigned long *) pte;
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if (!(page & 1))
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break;
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page &= PAGE_MASK;
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page += addr & ~PAGE_MASK;
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i = PAGE_SIZE-(addr & ~PAGE_MASK);
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if (i > count)
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i = count;
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memcpy_tofs(tmp,(void *) page,i);
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addr += i;
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tmp += i;
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count -= i;
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}
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file->f_pos = addr;
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return tmp-buf;
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}
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#ifndef mem_write
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static int mem_write(struct inode * inode, struct file * file,char * buf, int count)
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{
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unsigned long addr, pid, cr3;
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char *tmp;
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unsigned long pte, page;
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int i;
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if (count < 0)
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return -EINVAL;
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addr = file->f_pos;
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pid = inode->i_ino;
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pid >>= 16;
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cr3 = 0;
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for (i = 1 ; i < NR_TASKS ; i++)
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if (task[i] && task[i]->pid == pid) {
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cr3 = task[i]->tss.cr3;
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break;
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}
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if (!cr3)
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return -EACCES;
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tmp = buf;
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while (count > 0) {
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if (current->signal & ~current->blocked)
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break;
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pte = *PAGE_DIR_OFFSET(cr3,addr);
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if (!(pte & PAGE_PRESENT))
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break;
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pte &= PAGE_MASK;
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pte += PAGE_PTR(addr);
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page = *(unsigned long *) pte;
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if (!(page & PAGE_PRESENT))
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break;
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if (!(page & 2)) {
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do_wp_page(0,addr,current,0);
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continue;
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}
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page &= PAGE_MASK;
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page += addr & ~PAGE_MASK;
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i = PAGE_SIZE-(addr & ~PAGE_MASK);
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if (i > count)
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i = count;
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memcpy_fromfs((void *) page,tmp,i);
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addr += i;
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tmp += i;
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count -= i;
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}
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file->f_pos = addr;
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if (tmp != buf)
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return tmp-buf;
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if (current->signal & ~current->blocked)
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return -ERESTARTSYS;
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return 0;
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}
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#endif
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static int mem_lseek(struct inode * inode, struct file * file, off_t offset, int orig)
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{
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switch (orig) {
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case 0:
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file->f_pos = offset;
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return file->f_pos;
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case 1:
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file->f_pos += offset;
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return file->f_pos;
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default:
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return -EINVAL;
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}
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}
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static struct file_operations proc_mem_operations = {
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mem_lseek,
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mem_read,
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mem_write,
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NULL, /* mem_readdir */
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NULL, /* mem_select */
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NULL, /* mem_ioctl */
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NULL, /* mmap */
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NULL, /* no special open code */
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NULL, /* no special release code */
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NULL /* can't fsync */
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};
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struct inode_operations proc_mem_inode_operations = {
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&proc_mem_operations, /* default base directory file-ops */
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NULL, /* create */
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NULL, /* lookup */
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NULL, /* link */
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NULL, /* unlink */
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NULL, /* symlink */
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NULL, /* mkdir */
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NULL, /* rmdir */
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NULL, /* mknod */
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NULL, /* rename */
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NULL, /* readlink */
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NULL, /* follow_link */
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NULL, /* bmap */
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NULL, /* truncate */
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NULL /* permission */
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};
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