#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/posix_acl.h>
#include "reiserfs.h"
#include <linux/errno.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/slab.h>
#include <linux/posix_acl_xattr.h>
#include "xattr.h"
#include "acl.h"
#include <linux/uaccess.h>

static int __reiserfs_set_acl(struct reiserfs_transaction_handle *th,
                            struct inode *inode, int type,
                            struct posix_acl *acl);


int
reiserfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
        int error, error2;
        struct reiserfs_transaction_handle th;
        size_t jcreate_blocks;
        int size = acl ? posix_acl_xattr_size(acl->a_count) : 0;
        int update_mode = 0;
        umode_t mode = inode->i_mode;

        /*
         * Pessimism: We can't assume that anything from the xattr root up
         * has been created.
         */

        jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
                         reiserfs_xattr_nblocks(inode, size) * 2;

        reiserfs_write_lock(inode->i_sb);
        error = journal_begin(&th, inode->i_sb, jcreate_blocks);
        reiserfs_write_unlock(inode->i_sb);
        if (error == 0) {
                if (type == ACL_TYPE_ACCESS && acl) {
                        error = posix_acl_update_mode(inode, &mode, &acl);
                        if (error)
                                goto unlock;
                        update_mode = 1;
                }
                error = __reiserfs_set_acl(&th, inode, type, acl);
                if (!error && update_mode)
                        inode->i_mode = mode;
unlock:
                reiserfs_write_lock(inode->i_sb);
                error2 = journal_end(&th);
                reiserfs_write_unlock(inode->i_sb);
                if (error2)
                        error = error2;
        }

        return error;
}

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *reiserfs_posix_acl_from_disk(const void *value, size_t size)
{
        const char *end = (char *)value + size;
        int n, count;
        struct posix_acl *acl;

        if (!value)
                return NULL;
        if (size < sizeof(reiserfs_acl_header))
                return ERR_PTR(-EINVAL);
        if (((reiserfs_acl_header *) value)->a_version !=
            cpu_to_le32(REISERFS_ACL_VERSION))
                return ERR_PTR(-EINVAL);
        value = (char *)value + sizeof(reiserfs_acl_header);
        count = reiserfs_acl_count(size);
        if (count < 0)
                return ERR_PTR(-EINVAL);
        if (count == 0)
                return NULL;
        acl = posix_acl_alloc(count, GFP_NOFS);
        if (!acl)
                return ERR_PTR(-ENOMEM);
        for (n = 0; n < count; n++) {
                reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
                if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
                        goto fail;
                acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
                acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
                switch (acl->a_entries[n].e_tag) {
                case ACL_USER_OBJ:
                case ACL_GROUP_OBJ:
                case ACL_MASK:
                case ACL_OTHER:
                        value = (char *)value +
                            sizeof(reiserfs_acl_entry_short);
                        break;

                case ACL_USER:
                        value = (char *)value + sizeof(reiserfs_acl_entry);
                        if ((char *)value > end)
                                goto fail;
                        acl->a_entries[n].e_uid = 
                                make_kuid(&init_user_ns,
                                          le32_to_cpu(entry->e_id));
                        break;
                case ACL_GROUP:
                        value = (char *)value + sizeof(reiserfs_acl_entry);
                        if ((char *)value > end)
                                goto fail;
                        acl->a_entries[n].e_gid =
                                make_kgid(&init_user_ns,
                                          le32_to_cpu(entry->e_id));
                        break;

                default:
                        goto fail;
                }
        }
        if (value != end)
                goto fail;
        return acl;

fail:
        posix_acl_release(acl);
        return ERR_PTR(-EINVAL);
}

/*
 * Convert from in-memory to filesystem representation.
 */
static void *reiserfs_posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
{
        reiserfs_acl_header *ext_acl;
        char *e;
        int n;

        *size = reiserfs_acl_size(acl->a_count);
        ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
                                                  acl->a_count *
                                                  sizeof(reiserfs_acl_entry),
                                                  GFP_NOFS);
        if (!ext_acl)
                return ERR_PTR(-ENOMEM);
        ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
        e = (char *)ext_acl + sizeof(reiserfs_acl_header);
        for (n = 0; n < acl->a_count; n++) {
                const struct posix_acl_entry *acl_e = &acl->a_entries[n];
                reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
                entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
                entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
                switch (acl->a_entries[n].e_tag) {
                case ACL_USER:
                        entry->e_id = cpu_to_le32(
                                from_kuid(&init_user_ns, acl_e->e_uid));
                        e += sizeof(reiserfs_acl_entry);
                        break;
                case ACL_GROUP:
                        entry->e_id = cpu_to_le32(
                                from_kgid(&init_user_ns, acl_e->e_gid));
                        e += sizeof(reiserfs_acl_entry);
                        break;

                case ACL_USER_OBJ:
                case ACL_GROUP_OBJ:
                case ACL_MASK:
                case ACL_OTHER:
                        e += sizeof(reiserfs_acl_entry_short);
                        break;

                default:
                        goto fail;
                }
        }
        return (char *)ext_acl;

fail:
        kfree(ext_acl);
        return ERR_PTR(-EINVAL);
}

/*
 * Inode operation get_posix_acl().
 *
 * inode->i_mutex: down
 * BKL held [before 2.5.x]
 */
struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
{
        char *name, *value;
        struct posix_acl *acl;
        int size;
        int retval;

        switch (type) {
        case ACL_TYPE_ACCESS:
                name = XATTR_NAME_POSIX_ACL_ACCESS;
                break;
        case ACL_TYPE_DEFAULT:
                name = XATTR_NAME_POSIX_ACL_DEFAULT;
                break;
        default:
                BUG();
        }

        size = reiserfs_xattr_get(inode, name, NULL, 0);
        if (size < 0) {
                if (size == -ENODATA || size == -ENOSYS)
                        return NULL;
                return ERR_PTR(size);
        }

        value = kmalloc(size, GFP_NOFS);
        if (!value)
                return ERR_PTR(-ENOMEM);

        retval = reiserfs_xattr_get(inode, name, value, size);
        if (retval == -ENODATA || retval == -ENOSYS) {
                /*
                 * This shouldn't actually happen as it should have
                 * been caught above.. but just in case
                 */
                acl = NULL;
        } else if (retval < 0) {
                acl = ERR_PTR(retval);
        } else {
                acl = reiserfs_posix_acl_from_disk(value, retval);
        }

        kfree(value);
        return acl;
}

/*
 * Inode operation set_posix_acl().
 *
 * inode->i_mutex: down
 * BKL held [before 2.5.x]
 */
static int
__reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
                 int type, struct posix_acl *acl)
{
        char *name;
        void *value = NULL;
        size_t size = 0;
        int error;

        switch (type) {
        case ACL_TYPE_ACCESS:
                name = XATTR_NAME_POSIX_ACL_ACCESS;
                break;
        case ACL_TYPE_DEFAULT:
                name = XATTR_NAME_POSIX_ACL_DEFAULT;
                if (!S_ISDIR(inode->i_mode))
                        return acl ? -EACCES : 0;
                break;
        default:
                return -EINVAL;
        }

        if (acl) {
                value = reiserfs_posix_acl_to_disk(acl, &size);
                if (IS_ERR(value))
                        return (int)PTR_ERR(value);
        }

        error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);

        /*
         * Ensure that the inode gets dirtied if we're only using
         * the mode bits and an old ACL didn't exist. We don't need
         * to check if the inode is hashed here since we won't get
         * called by reiserfs_inherit_default_acl().
         */
        if (error == -ENODATA) {
                error = 0;
                if (type == ACL_TYPE_ACCESS) {
                        inode->i_ctime = current_time(inode);
                        mark_inode_dirty(inode);
                }
        }

        kfree(value);

        if (!error)
                set_cached_acl(inode, type, acl);

        return error;
}

/*
 * dir->i_mutex: locked,
 * inode is new and not released into the wild yet
 */
int
reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
                             struct inode *dir, struct dentry *dentry,
                             struct inode *inode)
{
        struct posix_acl *default_acl, *acl;
        int err = 0;

        /* ACLs only get applied to files and directories */
        if (S_ISLNK(inode->i_mode))
                return 0;

        /*
         * ACLs can only be used on "new" objects, so if it's an old object
         * there is nothing to inherit from
         */
        if (get_inode_sd_version(dir) == STAT_DATA_V1)
                goto apply_umask;

        /*
         * Don't apply ACLs to objects in the .reiserfs_priv tree.. This
         * would be useless since permissions are ignored, and a pain because
         * it introduces locking cycles
         */
        if (IS_PRIVATE(dir)) {
                inode->i_flags |= S_PRIVATE;
                goto apply_umask;
        }

        err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
        if (err)
                return err;

        if (default_acl) {
                err = __reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
                                         default_acl);
                posix_acl_release(default_acl);
        }
        if (acl) {
                if (!err)
                        err = __reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS,
                                                 acl);
                posix_acl_release(acl);
        }

        return err;

apply_umask:
        /* no ACL, apply umask */
        inode->i_mode &= ~current_umask();
        return err;
}

/* This is used to cache the default acl before a new object is created.
 * The biggest reason for this is to get an idea of how many blocks will
 * actually be required for the create operation if we must inherit an ACL.
 * An ACL write can add up to 3 object creations and an additional file write
 * so we'd prefer not to reserve that many blocks in the journal if we can.
 * It also has the advantage of not loading the ACL with a transaction open,
 * this may seem silly, but if the owner of the directory is doing the
 * creation, the ACL may not be loaded since the permissions wouldn't require
 * it.
 * We return the number of blocks required for the transaction.
 */
int reiserfs_cache_default_acl(struct inode *inode)
{
        struct posix_acl *acl;
        int nblocks = 0;

        if (IS_PRIVATE(inode))
                return 0;

        acl = get_acl(inode, ACL_TYPE_DEFAULT);

        if (acl && !IS_ERR(acl)) {
                int size = reiserfs_acl_size(acl->a_count);

                /* Other xattrs can be created during inode creation. We don't
                 * want to claim too many blocks, so we check to see if we
                 * we need to create the tree to the xattrs, and then we
                 * just want two files. */
                nblocks = reiserfs_xattr_jcreate_nblocks(inode);
                nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);

                REISERFS_I(inode)->i_flags |= i_has_xattr_dir;

                /* We need to account for writes + bitmaps for two files */
                nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
                posix_acl_release(acl);
        }

        return nblocks;
}

/*
 * Called under i_mutex
 */
int reiserfs_acl_chmod(struct inode *inode)
{
        if (IS_PRIVATE(inode))
                return 0;
        if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
            !reiserfs_posixacl(inode->i_sb))
                return 0;

        return posix_acl_chmod(inode, inode->i_mode);
}