/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (c) 2024 Paulo Alcantara <pc@manguebit.com>
 */

#ifndef _CIFS_REPARSE_H
#define _CIFS_REPARSE_H

#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/uidgid.h>
#include "fs_context.h"
#include "cifsglob.h"
#include "../common/smbfsctl.h"

#define REPARSE_SYM_PATH_MAX 4060

/*
 * Used only by cifs.ko to ignore reparse points from files when client or
 * server doesn't support FSCTL_GET_REPARSE_POINT.
 */
#define IO_REPARSE_TAG_INTERNAL ((__u32)~0U)

static inline dev_t reparse_mkdev(void *ptr)
{
        u64 v = le64_to_cpu(*(__le64 *)ptr);

        return MKDEV(v & 0xffffffff, v >> 32);
}

static inline kuid_t wsl_make_kuid(struct cifs_sb_info *cifs_sb,
                                   void *ptr)
{
        u32 uid = le32_to_cpu(*(__le32 *)ptr);

        if (cifs_sb_flags(cifs_sb) & CIFS_MOUNT_OVERR_UID)
                return cifs_sb->ctx->linux_uid;
        return make_kuid(current_user_ns(), uid);
}

static inline kgid_t wsl_make_kgid(struct cifs_sb_info *cifs_sb,
                                   void *ptr)
{
        u32 gid = le32_to_cpu(*(__le32 *)ptr);

        if (cifs_sb_flags(cifs_sb) & CIFS_MOUNT_OVERR_GID)
                return cifs_sb->ctx->linux_gid;
        return make_kgid(current_user_ns(), gid);
}

static inline u64 reparse_mode_nfs_type(mode_t mode)
{
        switch (mode & S_IFMT) {
        case S_IFLNK: return NFS_SPECFILE_LNK;
        case S_IFBLK: return NFS_SPECFILE_BLK;
        case S_IFCHR: return NFS_SPECFILE_CHR;
        case S_IFIFO: return NFS_SPECFILE_FIFO;
        case S_IFSOCK: return NFS_SPECFILE_SOCK;
        }
        return 0;
}

static inline u32 reparse_mode_wsl_tag(mode_t mode)
{
        switch (mode & S_IFMT) {
        case S_IFLNK: return IO_REPARSE_TAG_LX_SYMLINK;
        case S_IFBLK: return IO_REPARSE_TAG_LX_BLK;
        case S_IFCHR: return IO_REPARSE_TAG_LX_CHR;
        case S_IFIFO: return IO_REPARSE_TAG_LX_FIFO;
        case S_IFSOCK: return IO_REPARSE_TAG_AF_UNIX;
        }
        return 0;
}

/*
 * Match a reparse point inode if reparse tag and ctime haven't changed.
 *
 * Windows Server updates ctime of reparse points when their data have changed.
 * The server doesn't allow changing reparse tags from existing reparse points,
 * though it's worth checking.
 */
static inline bool reparse_inode_match(struct inode *inode,
                                       struct cifs_fattr *fattr)
{
        struct cifsInodeInfo *cinode = CIFS_I(inode);
        struct timespec64 ctime = inode_get_ctime(inode);

        /*
         * Do not match reparse tags when client or server doesn't support
         * FSCTL_GET_REPARSE_POINT.  @fattr->cf_cifstag should contain correct
         * reparse tag from query dir response but the client won't be able to
         * read the reparse point data anyway.  This spares us a revalidation.
         */
        if (cinode->reparse_tag != IO_REPARSE_TAG_INTERNAL &&
            cinode->reparse_tag != fattr->cf_cifstag)
                return false;
        return (cinode->cifsAttrs & ATTR_REPARSE_POINT) &&
                timespec64_equal(&ctime, &fattr->cf_ctime);
}

static inline bool cifs_open_data_reparse(struct cifs_open_info_data *data)
{
        u32 attrs;
        bool ret;

        if (data->contains_posix_file_info) {
                struct smb311_posix_qinfo *fi = &data->posix_fi;

                attrs = le32_to_cpu(fi->DosAttributes);
                if (data->reparse_point) {
                        attrs |= ATTR_REPARSE_POINT;
                        fi->DosAttributes = cpu_to_le32(attrs);
                }

        } else {
                struct smb2_file_all_info *fi = &data->fi;

                attrs = le32_to_cpu(fi->Attributes);
                if (data->reparse_point) {
                        attrs |= ATTR_REPARSE_POINT;
                        fi->Attributes = cpu_to_le32(attrs);
                }
        }

        ret = attrs & ATTR_REPARSE_POINT;

        return ret;
}

bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
                                 struct cifs_fattr *fattr,
                                 struct cifs_open_info_data *data);
int create_reparse_symlink(const unsigned int xid, struct inode *inode,
                           struct dentry *dentry, struct cifs_tcon *tcon,
                           const char *full_path, const char *symname);
int mknod_reparse(unsigned int xid, struct inode *inode, struct dentry *dentry,
                  struct cifs_tcon *tcon, const char *full_path, umode_t mode,
                  dev_t dev);
struct reparse_data_buffer *smb2_get_reparse_point_buffer(const struct kvec *rsp_iov,
                                                          u32 *plen);

#endif /* _CIFS_REPARSE_H */