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Ernesto A. Fernández
d4797823ea
The driver is much closer to being usable, so I might start getting subtler bug reports soon. To make them easier to handle, put error messages all over the place. I should have done this from the beginning, but I guess I didn't fully understand the need back then. From now my general policy will be to use apfs_warn() for user errors or unsupported features; apfs_err() for things that are probably corruption or io errors; and apfs_alert() for things that are most likely bugs. These last two should be rare, so the same error/alert will be thrown by several layers in the callstack to provide as much information as possible. Be careful and don't flood the console on normal situations. Also, make messages with a log level lower than warning output their function name and line number, which I think will help debugging more than the actual messages. Signed-off-by: Ernesto A. Fernández <ernesto@corellium.com>
81 lines
1.9 KiB
C
81 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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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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/**
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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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struct apfs_nxsb_info *nxi = APFS_NXI(sb);
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char *target = NULL;
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int err;
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int size;
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down_read(&nxi->nx_big_sem);
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if (!dentry) {
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err = -ECHILD;
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goto fail;
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}
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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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apfs_err(sb, "symlink size read failed");
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err = size;
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goto fail;
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}
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target = kmalloc(size, GFP_KERNEL);
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if (!target) {
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err = -ENOMEM;
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goto fail;
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}
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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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apfs_err(sb, "symlink read failed");
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err = 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_err(sb, "bad link target in inode 0x%llx", apfs_ino(inode));
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err = -EFSCORRUPTED;
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goto fail;
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}
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up_read(&nxi->nx_big_sem);
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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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up_read(&nxi->nx_big_sem);
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return ERR_PTR(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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.update_time = apfs_update_time,
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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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