// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/fs/adfs/super.c
 *
 *  Copyright (C) 1997-1999 Russell King
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs_parser.h>
#include <linux/fs_context.h>
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/statfs.h>
#include <linux/user_namespace.h>
#include <linux/blkdev.h>
#include "adfs.h"
#include "dir_f.h"
#include "dir_fplus.h"

#define ADFS_SB_FLAGS SB_NOATIME

#define ADFS_DEFAULT_OWNER_MASK S_IRWXU
#define ADFS_DEFAULT_OTHER_MASK (S_IRWXG | S_IRWXO)

void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        va_start(args, fmt);
        vaf.fmt = fmt;
        vaf.va = &args;

        printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %pV\n",
                sb->s_id, function ? ": " : "",
                function ? function : "", &vaf);

        va_end(args);
}

void adfs_msg(struct super_block *sb, const char *pfx, const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        va_start(args, fmt);
        vaf.fmt = fmt;
        vaf.va = &args;
        printk("%sADFS-fs (%s): %pV\n", pfx, sb->s_id, &vaf);
        va_end(args);
}

static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
{
        unsigned int max_idlen;
        int i;

        /* sector size must be 256, 512 or 1024 bytes */
        if (dr->log2secsize != 8 &&
            dr->log2secsize != 9 &&
            dr->log2secsize != 10)
                return 1;

        /* idlen must be at least log2secsize + 3 */
        if (dr->idlen < dr->log2secsize + 3)
                return 1;

        /* we cannot have such a large disc that we
         * are unable to represent sector offsets in
         * 32 bits.  This works out at 2.0 TB.
         */
        if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
                return 1;

        /*
         * Maximum idlen is limited to 16 bits for new directories by
         * the three-byte storage of an indirect disc address.  For
         * big directories, idlen must be no greater than 19 v2 [1.0]
         */
        max_idlen = dr->format_version ? 19 : 16;
        if (dr->idlen > max_idlen)
                return 1;

        /* reserved bytes should be zero */
        for (i = 0; i < sizeof(dr->unused52); i++)
                if (dr->unused52[i] != 0)
                        return 1;

        return 0;
}

static void adfs_put_super(struct super_block *sb)
{
        struct adfs_sb_info *asb = ADFS_SB(sb);

        adfs_free_map(sb);
        kfree_rcu(asb, rcu);
}

static int adfs_show_options(struct seq_file *seq, struct dentry *root)
{
        struct adfs_sb_info *asb = ADFS_SB(root->d_sb);

        if (!uid_eq(asb->s_uid, GLOBAL_ROOT_UID))
                seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, asb->s_uid));
        if (!gid_eq(asb->s_gid, GLOBAL_ROOT_GID))
                seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, asb->s_gid));
        if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
                seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
        if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
                seq_printf(seq, ",othmask=%o", asb->s_other_mask);
        if (asb->s_ftsuffix != 0)
                seq_printf(seq, ",ftsuffix=%u", asb->s_ftsuffix);

        return 0;
}

enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix};

static const struct fs_parameter_spec adfs_param_spec[] = {
        fsparam_uid     ("uid",         Opt_uid),
        fsparam_gid     ("gid",         Opt_gid),
        fsparam_u32oct  ("ownmask",     Opt_ownmask),
        fsparam_u32oct  ("othmask",     Opt_othmask),
        fsparam_u32     ("ftsuffix",    Opt_ftsuffix),
        {}
};

static int adfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
        struct adfs_sb_info *asb = fc->s_fs_info;
        struct fs_parse_result result;
        int opt;

        opt = fs_parse(fc, adfs_param_spec, param, &result);
        if (opt < 0)
                return opt;

        switch (opt) {
        case Opt_uid:
                asb->s_uid = result.uid;
                break;
        case Opt_gid:
                asb->s_gid = result.gid;
                break;
        case Opt_ownmask:
                asb->s_owner_mask = result.uint_32;
                break;
        case Opt_othmask:
                asb->s_other_mask = result.uint_32;
                break;
        case Opt_ftsuffix:
                asb->s_ftsuffix = result.uint_32;
                break;
        default:
                return -EINVAL;
        }
        return 0;
}

static int adfs_reconfigure(struct fs_context *fc)
{
        struct adfs_sb_info *new_asb = fc->s_fs_info;
        struct adfs_sb_info *asb = ADFS_SB(fc->root->d_sb);

        sync_filesystem(fc->root->d_sb);
        fc->sb_flags |= ADFS_SB_FLAGS;

        /* Structure copy newly parsed options */
        *asb = *new_asb;

        return 0;
}

static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_sb;
        struct adfs_sb_info *sbi = ADFS_SB(sb);
        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);

        adfs_map_statfs(sb, buf);

        buf->f_type    = ADFS_SUPER_MAGIC;
        buf->f_namelen = sbi->s_namelen;
        buf->f_bsize   = sb->s_blocksize;
        buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
        buf->f_fsid    = u64_to_fsid(id);

        return 0;
}

static struct kmem_cache *adfs_inode_cachep;

static struct inode *adfs_alloc_inode(struct super_block *sb)
{
        struct adfs_inode_info *ei;
        ei = alloc_inode_sb(sb, adfs_inode_cachep, GFP_KERNEL);
        if (!ei)
                return NULL;
        return &ei->vfs_inode;
}

static void adfs_free_inode(struct inode *inode)
{
        kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
}

static int adfs_drop_inode(struct inode *inode)
{
        /* always drop inodes if we are read-only */
        return !IS_ENABLED(CONFIG_ADFS_FS_RW) || IS_RDONLY(inode);
}

static void init_once(void *foo)
{
        struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;

        inode_init_once(&ei->vfs_inode);
}

static int __init init_inodecache(void)
{
        adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
                                             sizeof(struct adfs_inode_info),
                                             0, (SLAB_RECLAIM_ACCOUNT|
                                                SLAB_ACCOUNT),
                                             init_once);
        if (adfs_inode_cachep == NULL)
                return -ENOMEM;
        return 0;
}

static void destroy_inodecache(void)
{
        /*
         * Make sure all delayed rcu free inodes are flushed before we
         * destroy cache.
         */
        rcu_barrier();
        kmem_cache_destroy(adfs_inode_cachep);
}

static const struct super_operations adfs_sops = {
        .alloc_inode    = adfs_alloc_inode,
        .free_inode     = adfs_free_inode,
        .drop_inode     = adfs_drop_inode,
        .write_inode    = adfs_write_inode,
        .put_super      = adfs_put_super,
        .statfs         = adfs_statfs,
        .show_options   = adfs_show_options,
};

static int adfs_probe(struct super_block *sb, unsigned int offset, int silent,
                      int (*validate)(struct super_block *sb,
                                      struct buffer_head *bh,
                                      struct adfs_discrecord **bhp))
{
        struct adfs_sb_info *asb = ADFS_SB(sb);
        struct adfs_discrecord *dr;
        struct buffer_head *bh;
        unsigned int blocksize = BLOCK_SIZE;
        int ret, try;

        for (try = 0; try < 2; try++) {
                /* try to set the requested block size */
                if (sb->s_blocksize != blocksize &&
                    !sb_set_blocksize(sb, blocksize)) {
                        if (!silent)
                                adfs_msg(sb, KERN_ERR,
                                         "error: unsupported blocksize");
                        return -EINVAL;
                }

                /* read the buffer */
                bh = sb_bread(sb, offset >> sb->s_blocksize_bits);
                if (!bh) {
                        adfs_msg(sb, KERN_ERR,
                                 "error: unable to read block %u, try %d",
                                 offset >> sb->s_blocksize_bits, try);
                        return -EIO;
                }

                /* validate it */
                ret = validate(sb, bh, &dr);
                if (ret) {
                        brelse(bh);
                        return ret;
                }

                /* does the block size match the filesystem block size? */
                blocksize = 1 << dr->log2secsize;
                if (sb->s_blocksize == blocksize) {
                        asb->s_map = adfs_read_map(sb, dr);
                        brelse(bh);
                        return PTR_ERR_OR_ZERO(asb->s_map);
                }

                brelse(bh);
        }

        return -EIO;
}

static int adfs_validate_bblk(struct super_block *sb, struct buffer_head *bh,
                              struct adfs_discrecord **drp)
{
        struct adfs_discrecord *dr;
        unsigned char *b_data;

        b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
        if (adfs_checkbblk(b_data))
                return -EILSEQ;

        /* Do some sanity checks on the ADFS disc record */
        dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
        if (adfs_checkdiscrecord(dr))
                return -EILSEQ;

        *drp = dr;
        return 0;
}

static int adfs_validate_dr0(struct super_block *sb, struct buffer_head *bh,
                              struct adfs_discrecord **drp)
{
        struct adfs_discrecord *dr;

        /* Do some sanity checks on the ADFS disc record */
        dr = (struct adfs_discrecord *)(bh->b_data + 4);
        if (adfs_checkdiscrecord(dr) || dr->nzones_high || dr->nzones != 1)
                return -EILSEQ;

        *drp = dr;
        return 0;
}

static int adfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
        struct adfs_discrecord *dr;
        struct object_info root_obj;
        struct adfs_sb_info *asb = sb->s_fs_info;
        struct inode *root;
        int ret = -EINVAL;
        int silent = fc->sb_flags & SB_SILENT;

        sb->s_flags |= ADFS_SB_FLAGS;

        sb->s_fs_info = asb;
        sb->s_magic = ADFS_SUPER_MAGIC;
        sb->s_time_gran = 10000000;

        /* Try to probe the filesystem boot block */
        ret = adfs_probe(sb, ADFS_DISCRECORD, 1, adfs_validate_bblk);
        if (ret == -EILSEQ)
                ret = adfs_probe(sb, 0, silent, adfs_validate_dr0);
        if (ret == -EILSEQ) {
                if (!silent)
                        adfs_msg(sb, KERN_ERR,
                                 "error: can't find an ADFS filesystem on dev %s.",
                                 sb->s_id);
                ret = -EINVAL;
        }
        if (ret)
                goto error;

        /* set up enough so that we can read an inode */
        sb->s_op = &adfs_sops;

        dr = adfs_map_discrecord(asb->s_map);

        root_obj.parent_id = root_obj.indaddr = le32_to_cpu(dr->root);
        root_obj.name_len  = 0;
        /* Set root object date as 01 Jan 1987 00:00:00 */
        root_obj.loadaddr  = 0xfff0003f;
        root_obj.execaddr  = 0xec22c000;
        root_obj.size      = ADFS_NEWDIR_SIZE;
        root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
                             ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;

        /*
         * If this is a F+ disk with variable length directories,
         * get the root_size from the disc record.
         */
        if (dr->format_version) {
                root_obj.size = le32_to_cpu(dr->root_size);
                asb->s_dir     = &adfs_fplus_dir_ops;
                asb->s_namelen = ADFS_FPLUS_NAME_LEN;
        } else {
                asb->s_dir     = &adfs_f_dir_ops;
                asb->s_namelen = ADFS_F_NAME_LEN;
        }
        /*
         * ,xyz hex filetype suffix may be added by driver
         * to files that have valid RISC OS filetype
         */
        if (asb->s_ftsuffix)
                asb->s_namelen += 4;

        set_default_d_op(sb, &adfs_dentry_operations);
        root = adfs_iget(sb, &root_obj);
        sb->s_root = d_make_root(root);
        if (!sb->s_root) {
                adfs_free_map(sb);
                adfs_error(sb, "get root inode failed\n");
                ret = -EIO;
                goto error;
        }
        return 0;

error:
        sb->s_fs_info = NULL;
        kfree(asb);
        return ret;
}

static int adfs_get_tree(struct fs_context *fc)
{
        return get_tree_bdev(fc, adfs_fill_super);
}

static void adfs_free_fc(struct fs_context *fc)
{
        struct adfs_context *asb = fc->s_fs_info;

        kfree(asb);
}

static const struct fs_context_operations adfs_context_ops = {
        .parse_param    = adfs_parse_param,
        .get_tree       = adfs_get_tree,
        .reconfigure    = adfs_reconfigure,
        .free           = adfs_free_fc,
};

static int adfs_init_fs_context(struct fs_context *fc)
{
        struct adfs_sb_info *asb;

        asb = kzalloc_obj(struct adfs_sb_info);
        if (!asb)
                return -ENOMEM;

        if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
                struct super_block *sb = fc->root->d_sb;
                struct adfs_sb_info *old_asb = ADFS_SB(sb);

                /* structure copy existing options before parsing */
                *asb = *old_asb;
        } else {
                /* set default options */
                asb->s_uid = GLOBAL_ROOT_UID;
                asb->s_gid = GLOBAL_ROOT_GID;
                asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
                asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
                asb->s_ftsuffix = 0;
        }

        fc->ops = &adfs_context_ops;
        fc->s_fs_info = asb;

        return 0;
}

static struct file_system_type adfs_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "adfs",
        .kill_sb        = kill_block_super,
        .fs_flags       = FS_REQUIRES_DEV,
        .init_fs_context = adfs_init_fs_context,
        .parameters     = adfs_param_spec,
};
MODULE_ALIAS_FS("adfs");

static int __init init_adfs_fs(void)
{
        int err = init_inodecache();
        if (err)
                goto out1;
        err = register_filesystem(&adfs_fs_type);
        if (err)
                goto out;
        return 0;
out:
        destroy_inodecache();
out1:
        return err;
}

static void __exit exit_adfs_fs(void)
{
        unregister_filesystem(&adfs_fs_type);
        destroy_inodecache();
}

module_init(init_adfs_fs)
module_exit(exit_adfs_fs)
MODULE_DESCRIPTION("Acorn Disc Filing System");
MODULE_LICENSE("GPL");