129 lines
2.5 KiB
C
129 lines
2.5 KiB
C
/*
|
|
* linux/fs/proc/link.c
|
|
*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
*
|
|
* /proc link-file handling code
|
|
*/
|
|
|
|
#include <asm/segment.h>
|
|
|
|
#include <linux/errno.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/minix_fs.h>
|
|
#include <linux/stat.h>
|
|
|
|
static int proc_readlink(struct inode *, char *, int);
|
|
static int proc_follow_link(struct inode *, struct inode *, int, int, struct inode **);
|
|
|
|
/*
|
|
* links can't do much...
|
|
*/
|
|
struct inode_operations proc_link_inode_operations = {
|
|
NULL, /* no file-operations */
|
|
NULL, /* create */
|
|
NULL, /* lookup */
|
|
NULL, /* link */
|
|
NULL, /* unlink */
|
|
NULL, /* symlink */
|
|
NULL, /* mkdir */
|
|
NULL, /* rmdir */
|
|
NULL, /* mknod */
|
|
NULL, /* rename */
|
|
proc_readlink, /* readlink */
|
|
proc_follow_link, /* follow_link */
|
|
NULL, /* bmap */
|
|
NULL, /* truncate */
|
|
NULL /* permission */
|
|
};
|
|
|
|
static int proc_follow_link(struct inode * dir, struct inode * inode,
|
|
int flag, int mode, struct inode ** res_inode)
|
|
{
|
|
unsigned int pid, ino;
|
|
struct task_struct * p;
|
|
int i;
|
|
|
|
*res_inode = NULL;
|
|
if (dir)
|
|
iput(dir);
|
|
if (!inode)
|
|
return -ENOENT;
|
|
if (!permission(inode, MAY_EXEC)) {
|
|
iput(inode);
|
|
return -EACCES;
|
|
}
|
|
ino = inode->i_ino;
|
|
pid = ino >> 16;
|
|
ino &= 0x0000ffff;
|
|
iput(inode);
|
|
for (i = 0 ; i < NR_TASKS ; i++)
|
|
if ((p = task[i]) && p->pid == pid)
|
|
break;
|
|
if (i >= NR_TASKS)
|
|
return -ENOENT;
|
|
inode = NULL;
|
|
switch (ino) {
|
|
case 4:
|
|
inode = p->pwd;
|
|
break;
|
|
case 5:
|
|
inode = p->root;
|
|
break;
|
|
case 6:
|
|
inode = p->executable;
|
|
break;
|
|
default:
|
|
switch (ino >> 8) {
|
|
case 1:
|
|
ino &= 0xff;
|
|
if (ino < NR_OPEN && p->filp[ino])
|
|
inode = p->filp[ino]->f_inode;
|
|
break;
|
|
case 2:
|
|
ino &= 0xff;
|
|
{ int j = ino;
|
|
struct vm_area_struct * mpnt;
|
|
for(mpnt = p->mmap; mpnt && j >= 0;
|
|
mpnt = mpnt->vm_next){
|
|
if(mpnt->vm_inode) {
|
|
if(j == 0) {
|
|
inode = mpnt->vm_inode;
|
|
break;
|
|
};
|
|
j--;
|
|
}
|
|
}
|
|
};
|
|
}
|
|
}
|
|
if (!inode)
|
|
return -ENOENT;
|
|
*res_inode = inode;
|
|
inode->i_count++;
|
|
return 0;
|
|
}
|
|
|
|
static int proc_readlink(struct inode * inode, char * buffer, int buflen)
|
|
{
|
|
int i;
|
|
unsigned int dev,ino;
|
|
char buf[64];
|
|
|
|
i = proc_follow_link(NULL, inode, 0, 0, &inode);
|
|
if (i)
|
|
return i;
|
|
if (!inode)
|
|
return -EIO;
|
|
dev = inode->i_dev;
|
|
ino = inode->i_ino;
|
|
iput(inode);
|
|
i = sprintf(buf,"[%04x]:%u", dev, ino);
|
|
if (buflen > i)
|
|
buflen = i;
|
|
i = 0;
|
|
while (i < buflen)
|
|
put_fs_byte(buf[i++],buffer++);
|
|
return i;
|
|
}
|