111 lines
2.2 KiB
C
111 lines
2.2 KiB
C
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/*
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* linux/fs/sysv/symlink.c
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*
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* minix/symlink.c
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* coh/symlink.c
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* Copyright (C) 1993 Pascal Haible, Bruno Haible
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*
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* sysv/symlink.c
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* Copyright (C) 1993 Bruno Haible
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*
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* SystemV/Coherent symlink handling code
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*/
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#include <asm/segment.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/sysv_fs.h>
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#include <linux/stat.h>
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static int sysv_readlink(struct inode *, char *, int);
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static int sysv_follow_link(struct inode *, struct inode *, int, int, struct inode **);
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/*
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* symlinks can't do much...
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*/
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struct inode_operations sysv_symlink_inode_operations = {
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NULL, /* no file-operations */
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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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sysv_readlink, /* readlink */
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sysv_follow_link, /* 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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static int sysv_follow_link(struct inode * dir, struct inode * inode,
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int flag, int mode, struct inode ** res_inode)
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{
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int error;
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struct buffer_head * bh;
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char * bh_data;
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*res_inode = NULL;
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if (!dir) {
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dir = current->root;
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dir->i_count++;
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}
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if (!inode) {
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iput(dir);
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return -ENOENT;
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}
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if (!S_ISLNK(inode->i_mode)) {
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iput(dir);
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*res_inode = inode;
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return 0;
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}
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if (current->link_count > 5) {
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iput(inode);
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iput(dir);
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return -ELOOP;
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}
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if (!(bh = sysv_file_bread(inode, 0, 0, &bh_data))) { /* is reading 1 block enough ?? */
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iput(inode);
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iput(dir);
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return -EIO;
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}
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iput(inode);
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current->link_count++;
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error = open_namei(bh_data,flag,mode,res_inode,dir);
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current->link_count--;
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brelse(bh);
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return error;
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}
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static int sysv_readlink(struct inode * inode, char * buffer, int buflen)
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{
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struct buffer_head * bh;
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char * bh_data;
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int i;
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char c;
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if (!S_ISLNK(inode->i_mode)) {
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iput(inode);
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return -EINVAL;
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}
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if (buflen > inode->i_sb->sv_block_size_1)
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buflen = inode->i_sb->sv_block_size_1;
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bh = sysv_file_bread(inode, 0, 0, &bh_data);
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iput(inode);
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if (!bh)
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return 0;
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i = 0;
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while (i<buflen && (c = bh_data[i])) {
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i++;
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put_fs_byte(c,buffer++);
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}
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brelse(bh);
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return i;
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}
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