| /* |
| * linux/fs/ext2/symlink.c |
| * |
| * Copyright (C) 1992, 1993 Remy Card (card@masi.ibp.fr) |
| * |
| * from |
| * |
| * linux/fs/minix/symlink.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * ext2 symlink handling code |
| */ |
| |
| #include <asm/segment.h> |
| |
| #include <linux/errno.h> |
| #include <linux/sched.h> |
| #include <linux/fs.h> |
| #include <linux/ext2_fs.h> |
| #include <linux/stat.h> |
| |
| static int ext2_readlink (struct inode *, char *, int); |
| static int ext2_follow_link (struct inode *, struct inode *, int, int, |
| struct inode **); |
| |
| /* |
| * symlinks can't do much... |
| */ |
| struct inode_operations ext2_symlink_inode_operations = { |
| NULL, /* no file-operations */ |
| NULL, /* create */ |
| NULL, /* lookup */ |
| NULL, /* link */ |
| NULL, /* unlink */ |
| NULL, /* symlink */ |
| NULL, /* mkdir */ |
| NULL, /* rmdir */ |
| NULL, /* mknod */ |
| NULL, /* rename */ |
| ext2_readlink, /* readlink */ |
| ext2_follow_link, /* follow_link */ |
| NULL, /* bmap */ |
| NULL, /* truncate */ |
| NULL /* permission */ |
| }; |
| |
| static int ext2_follow_link(struct inode * dir, struct inode * inode, |
| int flag, int mode, struct inode ** res_inode) |
| { |
| int error; |
| struct buffer_head * bh = NULL; |
| char * link; |
| |
| *res_inode = NULL; |
| if (!dir) { |
| dir = current->root; |
| dir->i_count ++; |
| } |
| if (!inode) { |
| iput (dir); |
| return -ENOENT; |
| } |
| if (!S_ISLNK(inode->i_mode)) { |
| iput (dir); |
| *res_inode = inode; |
| return 0; |
| } |
| if (current->link_count > 5) { |
| iput (dir); |
| iput (inode); |
| return -ELOOP; |
| } |
| if (inode->i_blocks) { |
| if (!(bh = ext2_bread (inode, 0, 0, &error))) { |
| iput (dir); |
| iput (inode); |
| return -EIO; |
| } |
| link = bh->b_data; |
| } else |
| link = (char *) inode->u.ext2_i.i_data; |
| current->link_count ++; |
| error = open_namei (link, flag, mode, res_inode, dir); |
| current->link_count --; |
| iput (inode); |
| if (bh) |
| brelse (bh); |
| return error; |
| } |
| |
| static int ext2_readlink (struct inode * inode, char * buffer, int buflen) |
| { |
| struct buffer_head * bh = NULL; |
| char * link; |
| int i, err; |
| char c; |
| |
| if (!S_ISLNK(inode->i_mode)) { |
| iput (inode); |
| return -EINVAL; |
| } |
| if (buflen > inode->i_sb->s_blocksize - 1) |
| buflen = inode->i_sb->s_blocksize - 1; |
| if (inode->i_blocks) { |
| bh = ext2_bread (inode, 0, 0, &err); |
| if (!bh) { |
| iput (inode); |
| return 0; |
| } |
| link = bh->b_data; |
| } |
| else |
| link = (char *) inode->u.ext2_i.i_data; |
| i = 0; |
| while (i < buflen && (c = link[i])) { |
| i ++; |
| put_fs_byte (c, buffer++); |
| } |
| iput (inode); |
| if (bh) |
| brelse (bh); |
| return i; |
| } |