| 1 | /** @file
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| 2 | *
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| 3 | * vboxsf -- VirtualBox Guest Additions for Linux:
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| 4 | * Operations for symbolic links.
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| 5 | */
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| 6 |
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| 7 | /*
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| 8 | * Copyright (C) 2010-2017 Oracle Corporation
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| 9 | *
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| 10 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 11 | * available from http://www.virtualbox.org. This file is free software;
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| 12 | * you can redistribute it and/or modify it under the terms of the GNU
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| 13 | * General Public License (GPL) as published by the Free Software
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| 14 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 15 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 16 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 17 | */
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| 18 |
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| 19 | #include "vfsmod.h"
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| 20 |
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| 21 | #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
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| 22 |
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| 23 | #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 5, 0)
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| 24 | #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)
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| 25 | static const char *sf_follow_link(struct dentry *dentry, void **cookie)
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| 26 | #else
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| 27 | static void *sf_follow_link(struct dentry *dentry, struct nameidata *nd)
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| 28 | #endif
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| 29 | {
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| 30 | struct inode *inode = dentry->d_inode;
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| 31 | struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
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| 32 | struct sf_inode_info *sf_i = GET_INODE_INFO(inode);
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| 33 | int error = -ENOMEM;
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| 34 | char *path = (char *)get_zeroed_page(GFP_KERNEL);
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| 35 | int rc;
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| 36 |
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| 37 | if (path) {
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| 38 | error = 0;
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| 39 | rc = VbglR0SfReadLink(&client_handle, &sf_g->map, sf_i->path,
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| 40 | PATH_MAX, path);
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| 41 | if (RT_FAILURE(rc)) {
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| 42 | LogFunc(("VbglR0SfReadLink failed, caller=%s, rc=%Rrc\n", __func__, rc));
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| 43 | free_page((unsigned long)path);
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| 44 | error = -EPROTO;
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| 45 | }
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| 46 | }
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| 47 | #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)
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| 48 | return error ? ERR_PTR(error) : (*cookie = path);
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| 49 | #else
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| 50 | nd_set_link(nd, error ? ERR_PTR(error) : path);
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| 51 | return NULL;
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| 52 | #endif
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| 53 | }
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| 54 |
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| 55 | #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)
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| 56 | static void sf_put_link(struct dentry *dentry, struct nameidata *nd,
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| 57 | void *cookie)
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| 58 | {
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| 59 | char *page = nd_get_link(nd);
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| 60 | if (!IS_ERR(page))
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| 61 | free_page((unsigned long)page);
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| 62 | }
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| 63 | #endif
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| 64 |
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| 65 | #else /* LINUX_VERSION_CODE >= KERNEL_VERSION(4, 5, 0) */
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| 66 | static const char *sf_get_link(struct dentry *dentry, struct inode *inode,
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| 67 | struct delayed_call *done)
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| 68 | {
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| 69 | struct sf_glob_info *sf_g = GET_GLOB_INFO(inode->i_sb);
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| 70 | struct sf_inode_info *sf_i = GET_INODE_INFO(inode);
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| 71 | char *path;
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| 72 | int rc;
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| 73 |
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| 74 | if (!dentry)
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| 75 | return ERR_PTR(-ECHILD);
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| 76 | path = kzalloc(PAGE_SIZE, GFP_KERNEL);
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| 77 | if (!path)
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| 78 | return ERR_PTR(-ENOMEM);
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| 79 | rc = VbglR0SfReadLink(&client_handle, &sf_g->map, sf_i->path, PATH_MAX,
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| 80 | path);
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| 81 | if (RT_FAILURE(rc)) {
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| 82 | LogFunc(("VbglR0SfReadLink failed, caller=%s, rc=%Rrc\n",
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| 83 | __func__, rc));
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| 84 | kfree(path);
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| 85 | return ERR_PTR(-EPROTO);
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| 86 | }
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| 87 | set_delayed_call(done, kfree_link, path);
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| 88 | return path;
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| 89 | }
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| 90 | #endif /* LINUX_VERSION_CODE < KERNEL_VERSION(4, 5, 0) */
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| 91 |
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| 92 | struct inode_operations sf_lnk_iops = {
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| 93 | #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0)
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| 94 | .readlink = generic_readlink,
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| 95 | #endif
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| 96 | #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 5, 0)
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| 97 | .get_link = sf_get_link
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| 98 | #elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)
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| 99 | .follow_link = sf_follow_link,
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| 100 | .put_link = free_page_put_link,
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| 101 | #else
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| 102 | .follow_link = sf_follow_link,
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| 103 | .put_link = sf_put_link
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| 104 | #endif
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| 105 | };
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| 106 |
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| 107 | #endif /* LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0) */
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