// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/hpfs/dir.c
 *
 *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
 *
 *  directory VFS functions
 */

#include <linux/slab.h>
#include "hpfs_fn.h"

static int hpfs_dir_release(struct inode *inode, struct file *filp)
{
        hpfs_lock(inode->i_sb);
        hpfs_del_pos(inode, &filp->f_pos);
        /*hpfs_write_if_changed(inode);*/
        hpfs_unlock(inode->i_sb);
        return 0;
}

/* This is slow, but it's not used often */

static loff_t hpfs_dir_lseek(struct file *filp, loff_t off, int whence)
{
        loff_t new_off = off + (whence == 1 ? filp->f_pos : 0);
        loff_t pos;
        struct quad_buffer_head qbh;
        struct inode *i = file_inode(filp);
        struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
        struct super_block *s = i->i_sb;

        /* Somebody else will have to figure out what to do here */
        if (whence == SEEK_DATA || whence == SEEK_HOLE)
                return -EINVAL;

        inode_lock(i);
        hpfs_lock(s);

        /*pr_info("dir lseek\n");*/
        if (new_off == 0 || new_off == 1 || new_off == 11 || new_off == 12 || new_off == 13) goto ok;
        pos = ((loff_t) hpfs_de_as_down_as_possible(s, hpfs_inode->i_dno) << 4) + 1;
        while (pos != new_off) {
                if (map_pos_dirent(i, &pos, &qbh)) hpfs_brelse4(&qbh);
                else goto fail;
                if (pos == 12) goto fail;
        }
        if (unlikely(hpfs_add_pos(i, &filp->f_pos) < 0)) {
                hpfs_unlock(s);
                inode_unlock(i);
                return -ENOMEM;
        }
ok:
        filp->f_pos = new_off;
        hpfs_unlock(s);
        inode_unlock(i);
        return new_off;
fail:
        /*pr_warn("illegal lseek: %016llx\n", new_off);*/
        hpfs_unlock(s);
        inode_unlock(i);
        return -ESPIPE;
}

static int hpfs_readdir(struct file *file, struct dir_context *ctx)
{
        struct inode *inode = file_inode(file);
        struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
        struct quad_buffer_head qbh;
        struct hpfs_dirent *de;
        int lc;
        loff_t next_pos;
        unsigned char *tempname;
        int c1, c2 = 0;
        int ret = 0;

        hpfs_lock(inode->i_sb);

        if (hpfs_sb(inode->i_sb)->sb_chk) {
                if (hpfs_chk_sectors(inode->i_sb, inode->i_ino, 1, "dir_fnode")) {
                        ret = -EFSERROR;
                        goto out;
                }
                if (hpfs_chk_sectors(inode->i_sb, hpfs_inode->i_dno, 4, "dir_dnode")) {
                        ret = -EFSERROR;
                        goto out;
                }
        }
        if (hpfs_sb(inode->i_sb)->sb_chk >= 2) {
                struct buffer_head *bh;
                struct fnode *fno;
                int e = 0;
                if (!(fno = hpfs_map_fnode(inode->i_sb, inode->i_ino, &bh))) {
                        ret = -EIOERROR;
                        goto out;
                }
                if (!fnode_is_dir(fno)) {
                        e = 1;
                        hpfs_error(inode->i_sb, "not a directory, fnode %08lx",
                                        (unsigned long)inode->i_ino);
                }
                if (hpfs_inode->i_dno != le32_to_cpu(fno->u.external[0].disk_secno)) {
                        e = 1;
                        hpfs_error(inode->i_sb, "corrupted inode: i_dno == %08x, fnode -> dnode == %08x", hpfs_inode->i_dno, le32_to_cpu(fno->u.external[0].disk_secno));
                }
                brelse(bh);
                if (e) {
                        ret = -EFSERROR;
                        goto out;
                }
        }
        lc = hpfs_sb(inode->i_sb)->sb_lowercase;
        if (ctx->pos == 12) { /* diff -r requires this (note, that diff -r */
                ctx->pos = 13; /* also fails on msdos filesystem in 2.0) */
                goto out;
        }
        if (ctx->pos == 13) {
                ret = -ENOENT;
                goto out;
        }
        
        while (1) {
                again:
                /* This won't work when cycle is longer than number of dirents
                   accepted by filldir, but what can I do?
                   maybe killall -9 ls helps */
                if (hpfs_sb(inode->i_sb)->sb_chk)
                        if (hpfs_stop_cycles(inode->i_sb, ctx->pos, &c1, &c2, "hpfs_readdir")) {
                                ret = -EFSERROR;
                                goto out;
                        }
                if (ctx->pos == 12)
                        goto out;
                if (ctx->pos == 3 || ctx->pos == 4 || ctx->pos == 5) {
                        pr_err("pos==%d\n", (int)ctx->pos);
                        goto out;
                }
                if (ctx->pos == 0) {
                        if (!dir_emit_dot(file, ctx))
                                goto out;
                        ctx->pos = 11;
                }
                if (ctx->pos == 11) {
                        if (!dir_emit(ctx, "..", 2, hpfs_inode->i_parent_dir, DT_DIR))
                                goto out;
                        ctx->pos = 1;
                }
                if (ctx->pos == 1) {
                        ret = hpfs_add_pos(inode, &file->f_pos);
                        if (unlikely(ret < 0))
                                goto out;
                        ctx->pos = ((loff_t) hpfs_de_as_down_as_possible(inode->i_sb, hpfs_inode->i_dno) << 4) + 1;
                }
                next_pos = ctx->pos;
                if (!(de = map_pos_dirent(inode, &next_pos, &qbh))) {
                        ctx->pos = next_pos;
                        ret = -EIOERROR;
                        goto out;
                }
                if (de->first || de->last) {
                        if (hpfs_sb(inode->i_sb)->sb_chk) {
                                if (de->first && !de->last && (de->namelen != 2
                                    || de ->name[0] != 1 || de->name[1] != 1))
                                        hpfs_error(inode->i_sb, "hpfs_readdir: bad ^A^A entry; pos = %08lx", (unsigned long)ctx->pos);
                                if (de->last && (de->namelen != 1 || de ->name[0] != 255))
                                        hpfs_error(inode->i_sb, "hpfs_readdir: bad \\377 entry; pos = %08lx", (unsigned long)ctx->pos);
                        }
                        hpfs_brelse4(&qbh);
                        ctx->pos = next_pos;
                        goto again;
                }
                tempname = hpfs_translate_name(inode->i_sb, de->name, de->namelen, lc, de->not_8x3);
                if (!dir_emit(ctx, tempname, de->namelen, le32_to_cpu(de->fnode), DT_UNKNOWN)) {
                        if (tempname != de->name) kfree(tempname);
                        hpfs_brelse4(&qbh);
                        goto out;
                }
                ctx->pos = next_pos;
                if (tempname != de->name) kfree(tempname);
                hpfs_brelse4(&qbh);
        }
out:
        hpfs_unlock(inode->i_sb);
        return ret;
}

/*
 * lookup.  Search the specified directory for the specified name, set
 * *result to the corresponding inode.
 *
 * lookup uses the inode number to tell read_inode whether it is reading
 * the inode of a directory or a file -- file ino's are odd, directory
 * ino's are even.  read_inode avoids i/o for file inodes; everything
 * needed is up here in the directory.  (And file fnodes are out in
 * the boondocks.)
 *
 *    - M.P.: this is over, sometimes we've got to read file's fnode for eas
 *            inode numbers are just fnode sector numbers; iget lock is used
 *            to tell read_inode to read fnode or not.
 */

struct dentry *hpfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
        const unsigned char *name = dentry->d_name.name;
        unsigned len = dentry->d_name.len;
        struct quad_buffer_head qbh;
        struct hpfs_dirent *de;
        ino_t ino;
        int err;
        struct inode *result = NULL;
        struct hpfs_inode_info *hpfs_result;

        hpfs_lock(dir->i_sb);
        if ((err = hpfs_chk_name(name, &len))) {
                if (err == -ENAMETOOLONG) {
                        hpfs_unlock(dir->i_sb);
                        return ERR_PTR(-ENAMETOOLONG);
                }
                goto end_add;
        }

        /*
         * '.' and '..' will never be passed here.
         */

        de = map_dirent(dir, hpfs_i(dir)->i_dno, name, len, NULL, &qbh);

        /*
         * This is not really a bailout, just means file not found.
         */

        if (!de) goto end;

        /*
         * Get inode number, what we're after.
         */

        ino = le32_to_cpu(de->fnode);

        /*
         * Go find or make an inode.
         */

        result = iget_locked(dir->i_sb, ino);
        if (!result) {
                hpfs_error(dir->i_sb, "hpfs_lookup: can't get inode");
                result = ERR_PTR(-ENOMEM);
                goto bail1;
        }
        if (inode_state_read_once(result) & I_NEW) {
                hpfs_init_inode(result);
                if (de->directory)
                        hpfs_read_inode(result);
                else if (le32_to_cpu(de->ea_size) && hpfs_sb(dir->i_sb)->sb_eas)
                        hpfs_read_inode(result);
                else {
                        result->i_mode |= S_IFREG;
                        result->i_mode &= ~0111;
                        result->i_op = &hpfs_file_iops;
                        result->i_fop = &hpfs_file_ops;
                        set_nlink(result, 1);
                }
                unlock_new_inode(result);
        }
        hpfs_result = hpfs_i(result);
        if (!de->directory) hpfs_result->i_parent_dir = dir->i_ino;

        if (de->has_acl || de->has_xtd_perm) if (!sb_rdonly(dir->i_sb)) {
                hpfs_error(result->i_sb, "ACLs or XPERM found. This is probably HPFS386. This driver doesn't support it now. Send me some info on these structures");
                iput(result);
                result = ERR_PTR(-EINVAL);
                goto bail1;
        }

        /*
         * Fill in the info from the directory if this is a newly created
         * inode.
         */

        if (!inode_get_ctime_sec(result)) {
                time64_t csec = local_to_gmt(dir->i_sb, le32_to_cpu(de->creation_date));

                inode_set_ctime(result, csec ? csec : 1, 0);
                inode_set_mtime(result,
                                local_to_gmt(dir->i_sb, le32_to_cpu(de->write_date)),
                                0);
                inode_set_atime(result,
                                local_to_gmt(dir->i_sb, le32_to_cpu(de->read_date)),
                                0);
                hpfs_result->i_ea_size = le32_to_cpu(de->ea_size);
                if (!hpfs_result->i_ea_mode && de->read_only)
                        result->i_mode &= ~0222;
                if (!de->directory) {
                        if (result->i_size == -1) {
                                result->i_size = le32_to_cpu(de->file_size);
                                result->i_data.a_ops = &hpfs_aops;
                                hpfs_i(result)->mmu_private = result->i_size;
                        /*
                         * i_blocks should count the fnode and any anodes.
                         * We count 1 for the fnode and don't bother about
                         * anodes -- the disk heads are on the directory band
                         * and we want them to stay there.
                         */
                                result->i_blocks = 1 + ((result->i_size + 511) >> 9);
                        }
                }
        }

bail1:
        hpfs_brelse4(&qbh);

        /*
         * Made it.
         */

end:
end_add:
        hpfs_unlock(dir->i_sb);
        return d_splice_alias(result, dentry);
}

const struct file_operations hpfs_dir_ops =
{
        .llseek         = hpfs_dir_lseek,
        .read           = generic_read_dir,
        .iterate_shared = hpfs_readdir,
        .release        = hpfs_dir_release,
        .fsync          = hpfs_file_fsync,
        .unlocked_ioctl = hpfs_ioctl,
        .compat_ioctl   = compat_ptr_ioctl,
};