/*      $NetBSD: v7fs_file.c,v 1.7 2022/02/11 10:55:15 hannken Exp $    */

/*-
* Copyright (c) 2011 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by UCHIYAMA Yasushi.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: v7fs_file.c,v 1.7 2022/02/11 10:55:15 hannken Exp $");
#if defined _KERNEL_OPT
#include "opt_v7fs.h"
#endif

#include <sys/param.h>
#ifdef _KERNEL
#include <sys/systm.h>
#else
#include <stdio.h>
#include <string.h>
#include <errno.h>
#endif

#include "v7fs.h"
#include "v7fs_impl.h"
#include "v7fs_endian.h"
#include "v7fs_inode.h"
#include "v7fs_dirent.h"
#include "v7fs_file.h"
#include "v7fs_datablock.h"

#ifdef V7FS_FILE_DEBUG
#define DPRINTF(fmt, args...)   printf("%s: " fmt, __func__, ##args)
#else
#define DPRINTF(fmt, args...)   ((void)0)
#endif

static int lookup_subr(struct v7fs_self *, void *, v7fs_daddr_t, size_t);
static int remove_subr(struct v7fs_self *, void *, v7fs_daddr_t, size_t);

int
v7fs_file_lookup_by_name(struct v7fs_self *fs, struct v7fs_inode *parent_dir,
   const char *name, size_t namelen, v7fs_ino_t *ino)
{
       char filename[V7FS_NAME_MAX + 1];
       int error;

       v7fs_dirent_filename(filename, name, namelen);
       DPRINTF("%s(%.*s) dir=%d\n", filename, (int)namelen, name,
           parent_dir->inode_number);

       struct v7fs_lookup_arg lookup_arg = { .name = filename,
                                             .inode_number = 0 };
       if ((error = v7fs_datablock_foreach(fs, parent_dir, lookup_subr,
                   &lookup_arg)) != V7FS_ITERATOR_BREAK) {
               DPRINTF("not found.\n");
               return ENOENT;
       }

       *ino = lookup_arg.inode_number;
       DPRINTF("done. ino=%d\n", *ino);

       return 0;
}

static int
lookup_subr(struct v7fs_self *fs, void *ctx, v7fs_daddr_t blk, size_t sz)
{
       struct v7fs_lookup_arg *p = (struct v7fs_lookup_arg *)ctx;
       struct v7fs_dirent *dir;
       const char *name = p->name;
       void *buf;
       size_t i, n;
       int ret = 0;

       if (!(buf = scratch_read(fs, blk)))
               return EIO;

       dir = (struct v7fs_dirent *)buf;
       n = sz / sizeof(*dir);
       v7fs_dirent_endian_convert(fs, dir, n);

       for (i = 0; i < n; i++, dir++) {
               if (dir->inode_number < 1) {
                       DPRINTF("*** bad inode #%d ***\n", dir->inode_number);
                       continue;
               }

               if (strncmp((const char *)dir->name, name, V7FS_NAME_MAX) == 0)
               {
                       p->inode_number = dir->inode_number;
                       ret =  V7FS_ITERATOR_BREAK; /* found */
                       break;
               }
       }
       scratch_free(fs, buf);

       return ret;
}

int
v7fs_file_allocate(struct v7fs_self *fs, struct v7fs_inode *parent_dir,
   const char *srcname, size_t srclen, struct v7fs_fileattr *attr,
   v7fs_ino_t *ino)
{
       struct v7fs_inode inode;
       struct v7fs_dirent *dir;
       int error;

       /* Check filename. */
       if (v7fs_file_lookup_by_name(fs, parent_dir, srcname, srclen,
           ino) == 0) {
               DPRINTF("%.*s exists\n", (int)srclen, srcname);
               return EEXIST;
       }

       /* Get new inode. */
       if ((error = v7fs_inode_allocate(fs, ino)))
               return error;

       /* Set initial attribute. */
       memset(&inode, 0, sizeof(inode));
       inode.inode_number = *ino;
       inode.mode = attr->mode;
       inode.uid = attr->uid;
       inode.gid = attr->gid;
       if (attr->ctime)
               inode.ctime = attr->ctime;
       if (attr->mtime)
               inode.mtime = attr->mtime;
       if (attr->atime)
               inode.atime = attr->atime;

       switch (inode.mode & V7FS_IFMT) {
       default:
               DPRINTF("Can't allocate %o type.\n", inode.mode);
               v7fs_inode_deallocate(fs, *ino);
               return EINVAL;
       case V7FS_IFCHR:
               /* FALLTHROUGH */
       case V7FS_IFBLK:
               inode.nlink = 1;
               inode.device = attr->device;
               inode.addr[0] = inode.device;
               break;
       case V7FSBSD_IFFIFO:
               /* FALLTHROUGH */
       case V7FSBSD_IFSOCK:
               /* FALLTHROUGH */
       case V7FSBSD_IFLNK:
               /* FALLTHROUGH */
       case V7FS_IFREG:
               inode.nlink = 1;
               break;
       case V7FS_IFDIR:
               inode.nlink = 2;        /* . + .. */
               if ((error = v7fs_datablock_expand(fs, &inode, sizeof(*dir) * 2
                   ))) {
                       v7fs_inode_deallocate(fs, *ino);
                       return error;
               }
               v7fs_daddr_t blk = inode.addr[0];
               void *buf;
               if (!(buf = scratch_read(fs, blk))) {
                       v7fs_inode_deallocate(fs, *ino);
                       return EIO;
               }
               dir = (struct v7fs_dirent *)buf;
               strcpy(dir[0].name, ".");
               dir[0].inode_number = V7FS_VAL16(fs, *ino);
               strcpy(dir[1].name, "..");
               dir[1].inode_number = V7FS_VAL16(fs, parent_dir->inode_number);
               if (!fs->io.write(fs->io.cookie, buf, blk)) {
                       scratch_free(fs, buf);
                       return EIO;
               }
               scratch_free(fs, buf);
               break;
       }

       v7fs_inode_writeback(fs, &inode);

       /* Link this inode to parent directory. */
       if ((error = v7fs_directory_add_entry(fs, parent_dir, *ino, srcname,
           srclen)))
       {
               DPRINTF("can't add dirent.\n");
               return error;
       }

       return 0;
}

int
v7fs_file_deallocate(struct v7fs_self *fs, struct v7fs_inode *parent_dir,
   const char *name, size_t namelen)
{
       v7fs_ino_t ino;
       struct v7fs_inode inode;
       int error;

       DPRINTF("%.*s\n", (int)namelen, name);
       if ((error = v7fs_file_lookup_by_name(fs, parent_dir, name, namelen,
           &ino))) {
               DPRINTF("no such a file: %s\n", name);
               return error;
       }
       DPRINTF("%.*s->#%d\n", (int)namelen, name, ino);
       if ((error = v7fs_inode_load(fs, &inode, ino)))
               return error;

       if (v7fs_inode_isdir(&inode)) {
               char filename[V7FS_NAME_MAX + 1];
               v7fs_dirent_filename(filename, name, namelen);
               /* Check parent */
               if (strncmp(filename, "..", V7FS_NAME_MAX) == 0) {
                       DPRINTF("can not remove '..'\n");
                       return EINVAL; /* t_vnops rename_dotdot */
               }
               /* Check empty */
               if (v7fs_inode_filesize(&inode) !=
                   sizeof(struct v7fs_dirent) * 2 /*"." + ".."*/) {
                       DPRINTF("directory not empty.\n");
                       return ENOTEMPTY;/* t_vnops dir_noempty, rename_dir(6)*/
               }
               error = v7fs_datablock_size_change(fs, 0, &inode);
               if (error)
                       return error;
               inode.nlink = 0;        /* remove this. */
       } else {
               /* Decrement reference count. */
               --inode.nlink;  /* regular file. */
               DPRINTF("%.*s nlink=%d\n", (int)namelen, name, inode.nlink);
       }


       if ((error = v7fs_directory_remove_entry(fs, parent_dir, name,
           namelen)))
               return error;
       DPRINTF("remove dirent\n");

       v7fs_inode_writeback(fs, &inode);

       return 0;
}

int
v7fs_directory_add_entry(struct v7fs_self *fs, struct v7fs_inode *parent_dir,
   v7fs_ino_t ino, const char *srcname, size_t srclen)
{
       struct v7fs_inode inode;
       struct v7fs_dirent *dir;
       int error = 0;
       v7fs_daddr_t blk;
       void *buf;
       char filename[V7FS_NAME_MAX + 1];

       /* Truncate filename. */
       v7fs_dirent_filename(filename, srcname, srclen);
       DPRINTF("%s(%.*s) %d\n", filename, (int)srclen, srcname, ino);

       /* Target inode */
       if ((error = v7fs_inode_load(fs, &inode, ino)))
               return error;

       /* Expand datablock. */
       if ((error = v7fs_datablock_expand(fs, parent_dir, sizeof(*dir))))
               return error;

       /* Read last entry. */
       if (!(blk = v7fs_datablock_last(fs, parent_dir,
           v7fs_inode_filesize(parent_dir))))
               return EIO;

       /* Load dirent block. This vnode(parent dir) is locked by VFS layer. */
       if (!(buf = scratch_read(fs, blk)))
               return EIO;

       size_t sz = v7fs_inode_filesize(parent_dir);
       sz = V7FS_RESIDUE_BSIZE(sz);    /* last block payload. */
       int n = sz / sizeof(*dir) - 1;
       /* Add dirent. */
       dir = (struct v7fs_dirent *)buf;
       dir[n].inode_number = V7FS_VAL16(fs, ino);
       memcpy((char *)dir[n].name, filename, V7FS_NAME_MAX);
       /* Write back datablock */
       if (!fs->io.write(fs->io.cookie, buf, blk))
               error = EIO;
       scratch_free(fs, buf);

       if (v7fs_inode_isdir(&inode)) {
               parent_dir->nlink++;
               v7fs_inode_writeback(fs, parent_dir);
       }

       DPRINTF("done. (dirent size=%dbyte)\n", parent_dir->filesize);

       return error;
}

int
v7fs_directory_remove_entry(struct v7fs_self *fs, struct v7fs_inode *parent_dir,
   const char *name, size_t namelen)
{
       struct v7fs_inode inode;
       char filename[V7FS_NAME_MAX + 1];
       int error;
       struct v7fs_dirent lastdirent;
       v7fs_daddr_t lastblk;
       size_t sz, lastsz;
       v7fs_off_t pos;
       void *buf;

       v7fs_dirent_filename(filename, name, namelen);

       /* Setup replaced entry. */
       sz = parent_dir->filesize;
       lastblk = v7fs_datablock_last(fs, parent_dir,
           v7fs_inode_filesize(parent_dir));
       lastsz = V7FS_RESIDUE_BSIZE(sz);
       pos = lastsz - sizeof(lastdirent);

       if (!(buf = scratch_read(fs, lastblk)))
               return EIO;
       lastdirent = *((struct v7fs_dirent *)((uint8_t *)buf + pos));
       scratch_free(fs, buf);
       DPRINTF("last dirent=%d %s pos=%d\n",
           V7FS_VAL16(fs, lastdirent.inode_number), lastdirent.name, pos);

       struct v7fs_lookup_arg lookup_arg =
           { .name = filename, .replace = &lastdirent/*disk endian */ };
       /* Search entry that removed. replace it to last dirent. */
       if ((error = v7fs_datablock_foreach(fs, parent_dir, remove_subr,
           &lookup_arg)) != V7FS_ITERATOR_BREAK)
               return ENOENT;

       /* Contract dirent entries. */
       v7fs_datablock_contract(fs, parent_dir, sizeof(lastdirent));
       DPRINTF("done. (dirent size=%dbyte)\n", parent_dir->filesize);

       /* Target inode */
       if ((error = v7fs_inode_load(fs, &inode, lookup_arg.inode_number)))
               return error;

       if (v7fs_inode_isdir(&inode)) {
               parent_dir->nlink--;
               v7fs_inode_writeback(fs, parent_dir);
       }

       return 0;
}

static int
remove_subr(struct v7fs_self *fs, void *ctx, v7fs_daddr_t blk, size_t sz)
{
       struct v7fs_lookup_arg *p = (struct v7fs_lookup_arg *)ctx;
       struct v7fs_dirent *dir;
       void *buf;
       size_t i;
       int ret = 0;

       DPRINTF("match start blk=%x\n", blk);
       if (!(buf = scratch_read(fs, blk)))
               return EIO;

       dir = (struct v7fs_dirent *)buf;

       for (i = 0; i < sz / sizeof(*dir); i++, dir++) {
               DPRINTF("%d\n", V7FS_VAL16(fs, dir->inode_number));
               if (strncmp(p->name,
                       (const char *)dir->name, V7FS_NAME_MAX) == 0) {
                       p->inode_number = V7FS_VAL16(fs, dir->inode_number);
                       /* Replace to last dirent. */
                       *dir = *(p->replace); /* disk endian */
                       /* Write back. */
                       if (!fs->io.write(fs->io.cookie, buf, blk))
                               ret = EIO;
                       else
                               ret = V7FS_ITERATOR_BREAK;
                       break;
               }
       }
       scratch_free(fs, buf);

       return ret;
}

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