| /* |
| * 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; |
| 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; |
| } |