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Ernesto A. Fernández
50dba078e8
Starting with kernel version 4.10, a NULL value for the ->readlink() method defaults to generic_readlink(), or to a similar codepath. For older kernels this field must be set explicitly, otherwise the readlink syscall will fail. Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
71 lines
1.7 KiB
C
71 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/apfs/symlink.c
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*
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* Copyright (C) 2018 Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
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*/
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include "apfs.h"
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#include "message.h"
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#include "xattr.h"
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/**
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* apfs_get_link - Follow a symbolic link
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* @dentry: dentry for the link
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* @inode: inode for the link
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* @done: delayed call to free the returned buffer after use
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*
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* Returns a pointer to a buffer containing the target path, or an appropriate
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* error pointer in case of failure.
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*/
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static const char *apfs_get_link(struct dentry *dentry, struct inode *inode,
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struct delayed_call *done)
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{
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struct super_block *sb = inode->i_sb;
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char *target, *err;
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int size;
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if (!dentry)
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return ERR_PTR(-ECHILD);
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size = apfs_xattr_get(inode, APFS_XATTR_NAME_SYMLINK,
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NULL /* buffer */, 0 /* size */);
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if (size < 0) /* TODO: return a better error code */
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return ERR_PTR(size);
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target = kmalloc(size, GFP_KERNEL);
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if (!target)
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return ERR_PTR(-ENOMEM);
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size = apfs_xattr_get(inode, APFS_XATTR_NAME_SYMLINK, target, size);
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if (size < 0) {
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err = ERR_PTR(size);
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goto fail;
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}
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if (size == 0 || *(target + size - 1) != 0) {
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/* Target path must be NULL-terminated */
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apfs_alert(sb, "bad link target in inode 0x%llx",
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(unsigned long long) inode->i_ino);
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err = ERR_PTR(-EFSCORRUPTED);
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goto fail;
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}
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set_delayed_call(done, kfree_link, target);
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return target;
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fail:
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kfree(target);
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return err;
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}
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const struct inode_operations apfs_symlink_inode_operations = {
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.get_link = apfs_get_link,
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.getattr = apfs_getattr,
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.listxattr = apfs_listxattr,
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#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0) /* Now this is the default */
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.readlink = generic_readlink,
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#endif
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};
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