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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation 51 franklin street fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 23 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.458548087@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
224 lines
5.2 KiB
C
224 lines
5.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
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* Phillip Lougher <phillip@squashfs.org.uk>
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*
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* dir.c
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*/
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/*
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* This file implements code to read directories from disk.
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*
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* See namei.c for a description of directory organisation on disk.
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*/
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#include <linux/fs.h>
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#include <linux/vfs.h>
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#include <linux/slab.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "squashfs_fs_i.h"
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#include "squashfs.h"
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static const unsigned char squashfs_filetype_table[] = {
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DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_FIFO, DT_SOCK
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};
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/*
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* Lookup offset (f_pos) in the directory index, returning the
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* metadata block containing it.
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*
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* If we get an error reading the index then return the part of the index
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* (if any) we have managed to read - the index isn't essential, just
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* quicker.
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*/
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static int get_dir_index_using_offset(struct super_block *sb,
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u64 *next_block, int *next_offset, u64 index_start, int index_offset,
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int i_count, u64 f_pos)
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{
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struct squashfs_sb_info *msblk = sb->s_fs_info;
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int err, i, index, length = 0;
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unsigned int size;
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struct squashfs_dir_index dir_index;
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TRACE("Entered get_dir_index_using_offset, i_count %d, f_pos %lld\n",
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i_count, f_pos);
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/*
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* Translate from external f_pos to the internal f_pos. This
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* is offset by 3 because we invent "." and ".." entries which are
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* not actually stored in the directory.
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*/
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if (f_pos <= 3)
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return f_pos;
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f_pos -= 3;
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for (i = 0; i < i_count; i++) {
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err = squashfs_read_metadata(sb, &dir_index, &index_start,
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&index_offset, sizeof(dir_index));
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if (err < 0)
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break;
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index = le32_to_cpu(dir_index.index);
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if (index > f_pos)
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/*
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* Found the index we're looking for.
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*/
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break;
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size = le32_to_cpu(dir_index.size) + 1;
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/* size should never be larger than SQUASHFS_NAME_LEN */
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if (size > SQUASHFS_NAME_LEN)
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break;
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err = squashfs_read_metadata(sb, NULL, &index_start,
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&index_offset, size);
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if (err < 0)
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break;
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length = index;
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*next_block = le32_to_cpu(dir_index.start_block) +
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msblk->directory_table;
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}
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*next_offset = (length + *next_offset) % SQUASHFS_METADATA_SIZE;
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/*
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* Translate back from internal f_pos to external f_pos.
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*/
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return length + 3;
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}
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static int squashfs_readdir(struct file *file, struct dir_context *ctx)
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{
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struct inode *inode = file_inode(file);
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struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
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u64 block = squashfs_i(inode)->start + msblk->directory_table;
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int offset = squashfs_i(inode)->offset, length, err;
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unsigned int inode_number, dir_count, size, type;
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struct squashfs_dir_header dirh;
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struct squashfs_dir_entry *dire;
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TRACE("Entered squashfs_readdir [%llx:%x]\n", block, offset);
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dire = kmalloc(sizeof(*dire) + SQUASHFS_NAME_LEN + 1, GFP_KERNEL);
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if (dire == NULL) {
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ERROR("Failed to allocate squashfs_dir_entry\n");
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goto finish;
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}
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/*
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* Return "." and ".." entries as the first two filenames in the
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* directory. To maximise compression these two entries are not
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* stored in the directory, and so we invent them here.
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*
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* It also means that the external f_pos is offset by 3 from the
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* on-disk directory f_pos.
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*/
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while (ctx->pos < 3) {
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char *name;
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int i_ino;
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if (ctx->pos == 0) {
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name = ".";
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size = 1;
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i_ino = inode->i_ino;
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} else {
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name = "..";
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size = 2;
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i_ino = squashfs_i(inode)->parent;
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}
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if (!dir_emit(ctx, name, size, i_ino,
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squashfs_filetype_table[1]))
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goto finish;
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ctx->pos += size;
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}
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length = get_dir_index_using_offset(inode->i_sb, &block, &offset,
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squashfs_i(inode)->dir_idx_start,
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squashfs_i(inode)->dir_idx_offset,
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squashfs_i(inode)->dir_idx_cnt,
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ctx->pos);
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while (length < i_size_read(inode)) {
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/*
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* Read directory header
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*/
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err = squashfs_read_metadata(inode->i_sb, &dirh, &block,
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&offset, sizeof(dirh));
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if (err < 0)
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goto failed_read;
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length += sizeof(dirh);
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dir_count = le32_to_cpu(dirh.count) + 1;
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if (dir_count > SQUASHFS_DIR_COUNT)
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goto failed_read;
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while (dir_count--) {
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/*
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* Read directory entry.
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*/
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err = squashfs_read_metadata(inode->i_sb, dire, &block,
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&offset, sizeof(*dire));
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if (err < 0)
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goto failed_read;
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size = le16_to_cpu(dire->size) + 1;
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/* size should never be larger than SQUASHFS_NAME_LEN */
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if (size > SQUASHFS_NAME_LEN)
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goto failed_read;
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err = squashfs_read_metadata(inode->i_sb, dire->name,
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&block, &offset, size);
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if (err < 0)
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goto failed_read;
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length += sizeof(*dire) + size;
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if (ctx->pos >= length)
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continue;
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dire->name[size] = '\0';
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inode_number = le32_to_cpu(dirh.inode_number) +
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((short) le16_to_cpu(dire->inode_number));
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type = le16_to_cpu(dire->type);
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if (type > SQUASHFS_MAX_DIR_TYPE)
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goto failed_read;
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if (!dir_emit(ctx, dire->name, size,
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inode_number,
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squashfs_filetype_table[type]))
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goto finish;
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ctx->pos = length;
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}
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}
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finish:
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kfree(dire);
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return 0;
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failed_read:
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ERROR("Unable to read directory block [%llx:%x]\n", block, offset);
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kfree(dire);
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return 0;
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}
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const struct file_operations squashfs_dir_ops = {
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.read = generic_read_dir,
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.iterate_shared = squashfs_readdir,
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.llseek = generic_file_llseek,
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};
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