// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
 * Phillip Lougher <phillip@squashfs.org.uk>
 *
 * inode.c
 */

/*
 * This file implements code to create and read inodes from disk.
 *
 * Inodes in Squashfs are identified by a 48-bit inode which encodes the
 * location of the compressed metadata block containing the inode, and the byte
 * offset into that block where the inode is placed (<block, offset>).
 *
 * To maximise compression there are different inodes for each file type
 * (regular file, directory, device, etc.), the inode contents and length
 * varying with the type.
 *
 * To further maximise compression, two types of regular file inode and
 * directory inode are defined: inodes optimised for frequently occurring
 * regular files and directories, and extended types where extra
 * information has to be stored.
 */

#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/xattr.h>
#include <linux/pagemap.h>

#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "xattr.h"

/*
 * Initialise VFS inode with the base inode information common to all
 * Squashfs inode types.  Sqsh_ino contains the unswapped base inode
 * off disk.
 */
static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
                                struct squashfs_base_inode *sqsh_ino)
{
        uid_t i_uid;
        gid_t i_gid;
        int err;

        inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
        if (inode->i_ino == 0)
                return -EINVAL;

        err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid);
        if (err)
                return err;

        err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &i_gid);
        if (err)
                return err;

        i_uid_write(inode, i_uid);
        i_gid_write(inode, i_gid);
        inode_set_mtime(inode, le32_to_cpu(sqsh_ino->mtime), 0);
        inode_set_atime(inode, inode_get_mtime_sec(inode), 0);
        inode_set_ctime(inode, inode_get_mtime_sec(inode), 0);
        inode->i_mode = le16_to_cpu(sqsh_ino->mode);
        inode->i_size = 0;

        /* File type must not be set at this moment, for it will later be set by the caller. */
        if (inode->i_mode & S_IFMT)
                err = -EIO;

        return err;
}


struct inode *squashfs_iget(struct super_block *sb, long long ino,
                                unsigned int ino_number)
{
        struct inode *inode = iget_locked(sb, ino_number);
        int err;

        TRACE("Entered squashfs_iget\n");

        if (!inode)
                return ERR_PTR(-ENOMEM);
        if (!(inode_state_read_once(inode) & I_NEW))
                return inode;

        err = squashfs_read_inode(inode, ino);
        if (err) {
                iget_failed(inode);
                return ERR_PTR(err);
        }

        unlock_new_inode(inode);
        return inode;
}


/*
 * Initialise VFS inode by reading inode from inode table (compressed
 * metadata).  The format and amount of data read depends on type.
 */
int squashfs_read_inode(struct inode *inode, long long ino)
{
        struct super_block *sb = inode->i_sb;
        struct squashfs_sb_info *msblk = sb->s_fs_info;
        u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
        int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
        union squashfs_inode squashfs_ino;
        struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
        int xattr_id = SQUASHFS_INVALID_XATTR;

        TRACE("Entered squashfs_read_inode\n");

        /*
         * Read inode base common to all inode types.
         */
        err = squashfs_read_metadata(sb, sqshb_ino, &block,
                                &offset, sizeof(*sqshb_ino));
        if (err < 0)
                goto failed_read;

        err = squashfs_new_inode(sb, inode, sqshb_ino);
        if (err)
                goto failed_read;

        block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
        offset = SQUASHFS_INODE_OFFSET(ino);

        type = le16_to_cpu(sqshb_ino->inode_type);
        switch (type) {
        case SQUASHFS_REG_TYPE: {
                unsigned int frag_offset, frag;
                int frag_size;
                u64 frag_blk;
                struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;

                err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
                                                        sizeof(*sqsh_ino));
                if (err < 0)
                        goto failed_read;

                inode->i_size = le32_to_cpu(sqsh_ino->file_size);
                frag = le32_to_cpu(sqsh_ino->fragment);
                if (frag != SQUASHFS_INVALID_FRAG) {
                        /*
                         * the file cannot have a fragment (tailend) and have a
                         * file size a multiple of the block size
                         */
                        if ((inode->i_size & (msblk->block_size - 1)) == 0) {
                                err = -EINVAL;
                                goto failed_read;
                        }
                        frag_offset = le32_to_cpu(sqsh_ino->offset);
                        frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
                        if (frag_size < 0) {
                                err = frag_size;
                                goto failed_read;
                        }
                } else {
                        frag_blk = SQUASHFS_INVALID_BLK;
                        frag_size = 0;
                        frag_offset = 0;
                }

                set_nlink(inode, 1);
                inode->i_fop = &squashfs_file_operations;
                inode->i_mode |= S_IFREG;
                inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
                squashfs_i(inode)->fragment_block = frag_blk;
                squashfs_i(inode)->fragment_size = frag_size;
                squashfs_i(inode)->fragment_offset = frag_offset;
                squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
                squashfs_i(inode)->block_list_start = block;
                squashfs_i(inode)->offset = offset;
                squashfs_i(inode)->parent = 0;
                inode->i_data.a_ops = &squashfs_aops;

                TRACE("File inode %x:%x, start_block %llx, block_list_start "
                        "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
                        offset, squashfs_i(inode)->start, block, offset);
                break;
        }
        case SQUASHFS_LREG_TYPE: {
                unsigned int frag_offset, frag;
                int frag_size;
                u64 frag_blk;
                struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;

                err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
                                                        sizeof(*sqsh_ino));
                if (err < 0)
                        goto failed_read;

                inode->i_size = le64_to_cpu(sqsh_ino->file_size);
                if (inode->i_size < 0) {
                        err = -EINVAL;
                        goto failed_read;
                }
                frag = le32_to_cpu(sqsh_ino->fragment);
                if (frag != SQUASHFS_INVALID_FRAG) {
                        /*
                         * the file cannot have a fragment (tailend) and have a
                         * file size a multiple of the block size
                         */
                        if ((inode->i_size & (msblk->block_size - 1)) == 0) {
                                err = -EINVAL;
                                goto failed_read;
                        }
                        frag_offset = le32_to_cpu(sqsh_ino->offset);
                        frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
                        if (frag_size < 0) {
                                err = frag_size;
                                goto failed_read;
                        }
                } else {
                        frag_blk = SQUASHFS_INVALID_BLK;
                        frag_size = 0;
                        frag_offset = 0;
                }

                xattr_id = le32_to_cpu(sqsh_ino->xattr);
                set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
                inode->i_op = &squashfs_inode_ops;
                inode->i_fop = &squashfs_file_operations;
                inode->i_mode |= S_IFREG;
                inode->i_blocks = (inode->i_size -
                                le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;

                squashfs_i(inode)->fragment_block = frag_blk;
                squashfs_i(inode)->fragment_size = frag_size;
                squashfs_i(inode)->fragment_offset = frag_offset;
                squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
                squashfs_i(inode)->block_list_start = block;
                squashfs_i(inode)->offset = offset;
                squashfs_i(inode)->parent = 0;
                inode->i_data.a_ops = &squashfs_aops;

                TRACE("File inode %x:%x, start_block %llx, block_list_start "
                        "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
                        offset, squashfs_i(inode)->start, block, offset);
                break;
        }
        case SQUASHFS_DIR_TYPE: {
                struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;

                err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
                                sizeof(*sqsh_ino));
                if (err < 0)
                        goto failed_read;

                set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
                inode->i_size = le16_to_cpu(sqsh_ino->file_size);
                inode->i_op = &squashfs_dir_inode_ops;
                inode->i_fop = &squashfs_dir_ops;
                inode->i_mode |= S_IFDIR;
                squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
                squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
                squashfs_i(inode)->dir_idx_cnt = 0;
                squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);

                TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
                                SQUASHFS_INODE_BLK(ino), offset,
                                squashfs_i(inode)->start,
                                le16_to_cpu(sqsh_ino->offset));
                break;
        }
        case SQUASHFS_LDIR_TYPE: {
                struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;

                err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
                                sizeof(*sqsh_ino));
                if (err < 0)
                        goto failed_read;

                xattr_id = le32_to_cpu(sqsh_ino->xattr);
                set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
                inode->i_size = le32_to_cpu(sqsh_ino->file_size);
                inode->i_op = &squashfs_dir_inode_ops;
                inode->i_fop = &squashfs_dir_ops;
                inode->i_mode |= S_IFDIR;
                squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
                squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
                squashfs_i(inode)->dir_idx_start = block;
                squashfs_i(inode)->dir_idx_offset = offset;
                squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
                squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);

                TRACE("Long directory inode %x:%x, start_block %llx, offset "
                                "%x\n", SQUASHFS_INODE_BLK(ino), offset,
                                squashfs_i(inode)->start,
                                le16_to_cpu(sqsh_ino->offset));
                break;
        }
        case SQUASHFS_SYMLINK_TYPE:
        case SQUASHFS_LSYMLINK_TYPE: {
                struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;

                err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
                                sizeof(*sqsh_ino));
                if (err < 0)
                        goto failed_read;

                inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
                if (inode->i_size > PAGE_SIZE) {
                        ERROR("Corrupted symlink\n");
                        return -EINVAL;
                }

                set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
                inode->i_op = &squashfs_symlink_inode_ops;
                inode_nohighmem(inode);
                inode->i_data.a_ops = &squashfs_symlink_aops;
                inode->i_mode |= S_IFLNK;
                squashfs_i(inode)->start = block;
                squashfs_i(inode)->offset = offset;
                squashfs_i(inode)->parent = 0;

                if (type == SQUASHFS_LSYMLINK_TYPE) {
                        __le32 xattr;

                        err = squashfs_read_metadata(sb, NULL, &block,
                                                &offset, inode->i_size);
                        if (err < 0)
                                goto failed_read;
                        err = squashfs_read_metadata(sb, &xattr, &block,
                                                &offset, sizeof(xattr));
                        if (err < 0)
                                goto failed_read;
                        xattr_id = le32_to_cpu(xattr);
                }

                TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
                                "%x\n", SQUASHFS_INODE_BLK(ino), offset,
                                block, offset);
                break;
        }
        case SQUASHFS_BLKDEV_TYPE:
        case SQUASHFS_CHRDEV_TYPE: {
                struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
                unsigned int rdev;

                err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
                                sizeof(*sqsh_ino));
                if (err < 0)
                        goto failed_read;

                if (type == SQUASHFS_CHRDEV_TYPE)
                        inode->i_mode |= S_IFCHR;
                else
                        inode->i_mode |= S_IFBLK;
                set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
                rdev = le32_to_cpu(sqsh_ino->rdev);
                init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
                squashfs_i(inode)->parent = 0;

                TRACE("Device inode %x:%x, rdev %x\n",
                                SQUASHFS_INODE_BLK(ino), offset, rdev);
                break;
        }
        case SQUASHFS_LBLKDEV_TYPE:
        case SQUASHFS_LCHRDEV_TYPE: {
                struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
                unsigned int rdev;

                err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
                                sizeof(*sqsh_ino));
                if (err < 0)
                        goto failed_read;

                if (type == SQUASHFS_LCHRDEV_TYPE)
                        inode->i_mode |= S_IFCHR;
                else
                        inode->i_mode |= S_IFBLK;
                xattr_id = le32_to_cpu(sqsh_ino->xattr);
                inode->i_op = &squashfs_inode_ops;
                set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
                rdev = le32_to_cpu(sqsh_ino->rdev);
                init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
                squashfs_i(inode)->parent = 0;

                TRACE("Device inode %x:%x, rdev %x\n",
                                SQUASHFS_INODE_BLK(ino), offset, rdev);
                break;
        }
        case SQUASHFS_FIFO_TYPE:
        case SQUASHFS_SOCKET_TYPE: {
                struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;

                err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
                                sizeof(*sqsh_ino));
                if (err < 0)
                        goto failed_read;

                if (type == SQUASHFS_FIFO_TYPE)
                        inode->i_mode |= S_IFIFO;
                else
                        inode->i_mode |= S_IFSOCK;
                set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
                init_special_inode(inode, inode->i_mode, 0);
                squashfs_i(inode)->parent = 0;
                break;
        }
        case SQUASHFS_LFIFO_TYPE:
        case SQUASHFS_LSOCKET_TYPE: {
                struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;

                err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
                                sizeof(*sqsh_ino));
                if (err < 0)
                        goto failed_read;

                if (type == SQUASHFS_LFIFO_TYPE)
                        inode->i_mode |= S_IFIFO;
                else
                        inode->i_mode |= S_IFSOCK;
                xattr_id = le32_to_cpu(sqsh_ino->xattr);
                inode->i_op = &squashfs_inode_ops;
                set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
                init_special_inode(inode, inode->i_mode, 0);
                squashfs_i(inode)->parent = 0;
                break;
        }
        default:
                ERROR("Unknown inode type %d in squashfs_iget!\n", type);
                return -EINVAL;
        }

        if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
                err = squashfs_xattr_lookup(sb, xattr_id,
                                        &squashfs_i(inode)->xattr_count,
                                        &squashfs_i(inode)->xattr_size,
                                        &squashfs_i(inode)->xattr);
                if (err < 0)
                        goto failed_read;
                inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
                                + 1;
        } else
                squashfs_i(inode)->xattr_count = 0;

        return 0;

failed_read:
        ERROR("Unable to read inode 0x%llx\n", ino);
        return err;
}


const struct inode_operations squashfs_inode_ops = {
        .listxattr = squashfs_listxattr
};