// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/ext4/symlink.c
 *
 * Only fast symlinks left here - the rest is done by generic code. AV, 1999
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/symlink.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  ext4 symlink handling code
 */

#include <linux/fs.h>
#include <linux/namei.h>
#include "ext4.h"
#include "xattr.h"

static const char *ext4_encrypted_get_link(struct dentry *dentry,
                                           struct inode *inode,
                                           struct delayed_call *done)
{
        struct buffer_head *bh = NULL;
        const void *caddr;
        unsigned int max_size;
        const char *paddr;

        if (!dentry)
                return ERR_PTR(-ECHILD);

        if (ext4_inode_is_fast_symlink(inode)) {
                caddr = EXT4_I(inode)->i_data;
                max_size = sizeof(EXT4_I(inode)->i_data);
        } else {
                bh = ext4_bread(NULL, inode, 0, 0);
                if (IS_ERR(bh))
                        return ERR_CAST(bh);
                if (!bh) {
                        EXT4_ERROR_INODE(inode, "bad symlink.");
                        return ERR_PTR(-EFSCORRUPTED);
                }
                caddr = bh->b_data;
                max_size = inode->i_sb->s_blocksize;
        }

        paddr = fscrypt_get_symlink(inode, caddr, max_size, done);
        brelse(bh);
        return paddr;
}

static int ext4_encrypted_symlink_getattr(struct mnt_idmap *idmap,
                                          const struct path *path,
                                          struct kstat *stat, u32 request_mask,
                                          unsigned int query_flags)
{
        ext4_getattr(idmap, path, stat, request_mask, query_flags);

        return fscrypt_symlink_getattr(path, stat);
}

static void ext4_free_link(void *bh)
{
        brelse(bh);
}

static const char *ext4_get_link(struct dentry *dentry, struct inode *inode,
                                 struct delayed_call *callback)
{
        struct buffer_head *bh;
        char *inline_link;

        /*
         * Create a new inlined symlink is not supported, just provide a
         * method to read the leftovers.
         */
        if (ext4_has_inline_data(inode)) {
                if (!dentry)
                        return ERR_PTR(-ECHILD);

                inline_link = ext4_read_inline_link(inode);
                if (!IS_ERR(inline_link))
                        set_delayed_call(callback, kfree_link, inline_link);
                return inline_link;
        }

        if (!dentry) {
                bh = ext4_getblk(NULL, inode, 0, EXT4_GET_BLOCKS_CACHED_NOWAIT);
                if (IS_ERR(bh) || !bh)
                        return ERR_PTR(-ECHILD);
                if (!ext4_buffer_uptodate(bh)) {
                        brelse(bh);
                        return ERR_PTR(-ECHILD);
                }
        } else {
                bh = ext4_bread(NULL, inode, 0, 0);
                if (IS_ERR(bh))
                        return ERR_CAST(bh);
                if (!bh) {
                        EXT4_ERROR_INODE(inode, "bad symlink.");
                        return ERR_PTR(-EFSCORRUPTED);
                }
        }

        set_delayed_call(callback, ext4_free_link, bh);
        nd_terminate_link(bh->b_data, inode->i_size,
                          inode->i_sb->s_blocksize - 1);
        return bh->b_data;
}

const struct inode_operations ext4_encrypted_symlink_inode_operations = {
        .get_link       = ext4_encrypted_get_link,
        .setattr        = ext4_setattr,
        .getattr        = ext4_encrypted_symlink_getattr,
        .listxattr      = ext4_listxattr,
};

const struct inode_operations ext4_symlink_inode_operations = {
        .get_link       = ext4_get_link,
        .setattr        = ext4_setattr,
        .getattr        = ext4_getattr,
        .listxattr      = ext4_listxattr,
};

const struct inode_operations ext4_fast_symlink_inode_operations = {
        .get_link       = simple_get_link,
        .setattr        = ext4_setattr,
        .getattr        = ext4_getattr,
        .listxattr      = ext4_listxattr,
};