/*
 *  linux/fs/ioctl.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/syscalls.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/capability.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>

#include <asm/ioctls.h>

/* So that the fiemap access checks can't overflow on 32 bit machines. */
#define FIEMAP_MAX_EXTENTS      (UINT_MAX / sizeof(struct fiemap_extent))

/**
 * vfs_ioctl - call filesystem specific ioctl methods
 * @filp:       open file to invoke ioctl method on
 * @cmd:        ioctl command to execute
 * @arg:        command-specific argument for ioctl
 *
 * Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise
 * invokes filesystem specific ->ioctl method.  If neither method exists,
 * returns -ENOTTY.
 *
 * Returns 0 on success, -errno on error.
 */
static long vfs_ioctl(struct file *filp, unsigned int cmd,
                      unsigned long arg)
{
        int error = -ENOTTY;

        if (!filp->f_op)
                goto out;

        if (filp->f_op->unlocked_ioctl) {
                error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
                if (error == -ENOIOCTLCMD)
                        error = -EINVAL;
                goto out;
        } else if (filp->f_op->ioctl) {
                lock_kernel();
                error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,
                                          filp, cmd, arg);
                unlock_kernel();
        }

 out:
        return error;
}

static int ioctl_fibmap(struct file *filp, int __user *p)
{
        struct address_space *mapping = filp->f_mapping;
        int res, block;

        /* do we support this mess? */
        if (!mapping->a_ops->bmap)
                return -EINVAL;
        if (!capable(CAP_SYS_RAWIO))
                return -EPERM;
        res = get_user(block, p);
        if (res)
                return res;
        lock_kernel();
        res = mapping->a_ops->bmap(mapping, block);
        unlock_kernel();
        return put_user(res, p);
}

/**
 * fiemap_fill_next_extent - Fiemap helper function
 * @fieinfo:    Fiemap context passed into ->fiemap
 * @logical:    Extent logical start offset, in bytes
 * @phys:       Extent physical start offset, in bytes
 * @len:        Extent length, in bytes
 * @flags:      FIEMAP_EXTENT flags that describe this extent
 *
 * Called from file system ->fiemap callback. Will populate extent
 * info as passed in via arguments and copy to user memory. On
 * success, extent count on fieinfo is incremented.
 *
 * Returns 0 on success, -errno on error, 1 if this was the last
 * extent that will fit in user array.
 */
#define SET_UNKNOWN_FLAGS       (FIEMAP_EXTENT_DELALLOC)
#define SET_NO_UNMOUNTED_IO_FLAGS       (FIEMAP_EXTENT_DATA_ENCRYPTED)
#define SET_NOT_ALIGNED_FLAGS   (FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE)
int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical,
                            u64 phys, u64 len, u32 flags)
{
        struct fiemap_extent extent;
        struct fiemap_extent *dest = fieinfo->fi_extents_start;

        /* only count the extents */
        if (fieinfo->fi_extents_max == 0) {
                fieinfo->fi_extents_mapped++;
                return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
        }

        if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max)
                return 1;

        if (flags & SET_UNKNOWN_FLAGS)
                flags |= FIEMAP_EXTENT_UNKNOWN;
        if (flags & SET_NO_UNMOUNTED_IO_FLAGS)
                flags |= FIEMAP_EXTENT_ENCODED;
        if (flags & SET_NOT_ALIGNED_FLAGS)
                flags |= FIEMAP_EXTENT_NOT_ALIGNED;

        memset(&extent, 0, sizeof(extent));
        extent.fe_logical = logical;
        extent.fe_physical = phys;
        extent.fe_length = len;
        extent.fe_flags = flags;

        dest += fieinfo->fi_extents_mapped;
        if (copy_to_user(dest, &extent, sizeof(extent)))
                return -EFAULT;

        fieinfo->fi_extents_mapped++;
        if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max)
                return 1;
        return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
}
EXPORT_SYMBOL(fiemap_fill_next_extent);

/**
 * fiemap_check_flags - check validity of requested flags for fiemap
 * @fieinfo:    Fiemap context passed into ->fiemap
 * @fs_flags:   Set of fiemap flags that the file system understands
 *
 * Called from file system ->fiemap callback. This will compute the
 * intersection of valid fiemap flags and those that the fs supports. That
 * value is then compared against the user supplied flags. In case of bad user
 * flags, the invalid values will be written into the fieinfo structure, and
 * -EBADR is returned, which tells ioctl_fiemap() to return those values to
 * userspace. For this reason, a return code of -EBADR should be preserved.
 *
 * Returns 0 on success, -EBADR on bad flags.
 */
int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags)
{
        u32 incompat_flags;

        incompat_flags = fieinfo->fi_flags & ~(FIEMAP_FLAGS_COMPAT & fs_flags);
        if (incompat_flags) {
                fieinfo->fi_flags = incompat_flags;
                return -EBADR;
        }
        return 0;
}
EXPORT_SYMBOL(fiemap_check_flags);

static int fiemap_check_ranges(struct super_block *sb,
                               u64 start, u64 len, u64 *new_len)
{
        *new_len = len;

        if (len == 0)
                return -EINVAL;

        if (start > sb->s_maxbytes)
                return -EFBIG;

        /*
         * Shrink request scope to what the fs can actually handle.
         */
        if ((len > sb->s_maxbytes) ||
            (sb->s_maxbytes - len) < start)
                *new_len = sb->s_maxbytes - start;

        return 0;
}

static int ioctl_fiemap(struct file *filp, unsigned long arg)
{
        struct fiemap fiemap;
        struct fiemap_extent_info fieinfo = { 0, };
        struct inode *inode = filp->f_path.dentry->d_inode;
        struct super_block *sb = inode->i_sb;
        u64 len;
        int error;

        if (!inode->i_op->fiemap)
                return -EOPNOTSUPP;

        if (copy_from_user(&fiemap, (struct fiemap __user *)arg,
                           sizeof(struct fiemap)))
                return -EFAULT;

        if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS)
                return -EINVAL;

        error = fiemap_check_ranges(sb, fiemap.fm_start, fiemap.fm_length,
                                    &len);
        if (error)
                return error;

        fieinfo.fi_flags = fiemap.fm_flags;
        fieinfo.fi_extents_max = fiemap.fm_extent_count;
        fieinfo.fi_extents_start = (struct fiemap_extent *)(arg + sizeof(fiemap));

        if (fiemap.fm_extent_count != 0 &&
            !access_ok(VERIFY_WRITE, fieinfo.fi_extents_start,
                       fieinfo.fi_extents_max * sizeof(struct fiemap_extent)))
                return -EFAULT;

        if (fieinfo.fi_flags & FIEMAP_FLAG_SYNC)
                filemap_write_and_wait(inode->i_mapping);

        error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start, len);
        fiemap.fm_flags = fieinfo.fi_flags;
        fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped;
        if (copy_to_user((char *)arg, &fiemap, sizeof(fiemap)))
                error = -EFAULT;

        return error;
}

#ifdef CONFIG_BLOCK

#define blk_to_logical(inode, blk) (blk << (inode)->i_blkbits)
#define logical_to_blk(inode, offset) (offset >> (inode)->i_blkbits);

/*
 * @inode - the inode to map
 * @arg - the pointer to userspace where we copy everything to
 * @get_block - the fs's get_block function
 *
 * This does FIEMAP for block based inodes.  Basically it will just loop
 * through get_block until we hit the number of extents we want to map, or we
 * go past the end of the file and hit a hole.
 *
 * If it is possible to have data blocks beyond a hole past @inode->i_size, then
 * please do not use this function, it will stop at the first unmapped block
 * beyond i_size
 */
int generic_block_fiemap(struct inode *inode,
                         struct fiemap_extent_info *fieinfo, u64 start,
                         u64 len, get_block_t *get_block)
{
        struct buffer_head tmp;
        unsigned int start_blk;
        long long length = 0, map_len = 0;
        u64 logical = 0, phys = 0, size = 0;
        u32 flags = FIEMAP_EXTENT_MERGED;
        int ret = 0;

        if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC)))
                return ret;

        start_blk = logical_to_blk(inode, start);

        /* guard against change */
        mutex_lock(&inode->i_mutex);

        length = (long long)min_t(u64, len, i_size_read(inode));
        map_len = length;

        do {
                /*
                 * we set b_size to the total size we want so it will map as
                 * many contiguous blocks as possible at once
                 */
                memset(&tmp, 0, sizeof(struct buffer_head));
                tmp.b_size = map_len;

                ret = get_block(inode, start_blk, &tmp, 0);
                if (ret)
                        break;

                /* HOLE */
                if (!buffer_mapped(&tmp)) {
                        /*
                         * first hole after going past the EOF, this is our
                         * last extent
                         */
                        if (length <= 0) {
                                flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST;
                                ret = fiemap_fill_next_extent(fieinfo, logical,
                                                              phys, size,
                                                              flags);
                                break;
                        }

                        length -= blk_to_logical(inode, 1);

                        /* if we have holes up to/past EOF then we're done */
                        if (length <= 0)
                                break;

                        start_blk++;
                } else {
                        if (length <= 0 && size) {
                                ret = fiemap_fill_next_extent(fieinfo, logical,
                                                              phys, size,
                                                              flags);
                                if (ret)
                                        break;
                        }

                        logical = blk_to_logical(inode, start_blk);
                        phys = blk_to_logical(inode, tmp.b_blocknr);
                        size = tmp.b_size;
                        flags = FIEMAP_EXTENT_MERGED;

                        length -= tmp.b_size;
                        start_blk += logical_to_blk(inode, size);

                        /*
                         * if we are past the EOF we need to loop again to see
                         * if there is a hole so we can mark this extent as the
                         * last one, and if not keep mapping things until we
                         * find a hole, or we run out of slots in the extent
                         * array
                         */
                        if (length <= 0)
                                continue;

                        ret = fiemap_fill_next_extent(fieinfo, logical, phys,
                                                      size, flags);
                        if (ret)
                                break;
                }
                cond_resched();
        } while (1);

        mutex_unlock(&inode->i_mutex);

        /* if ret is 1 then we just hit the end of the extent array */
        if (ret == 1)
                ret = 0;

        return ret;
}
EXPORT_SYMBOL(generic_block_fiemap);

#endif  /*  CONFIG_BLOCK  */

static int file_ioctl(struct file *filp, unsigned int cmd,
                unsigned long arg)
{
        struct inode *inode = filp->f_path.dentry->d_inode;
        int __user *p = (int __user *)arg;

        switch (cmd) {
        case FIBMAP:
                return ioctl_fibmap(filp, p);
        case FS_IOC_FIEMAP:
                return ioctl_fiemap(filp, arg);
        case FIGETBSZ:
                return put_user(inode->i_sb->s_blocksize, p);
        case FIONREAD:
                return put_user(i_size_read(inode) - filp->f_pos, p);
        }

        return vfs_ioctl(filp, cmd, arg);
}

static int ioctl_fionbio(struct file *filp, int __user *argp)
{
        unsigned int flag;
        int on, error;

        error = get_user(on, argp);
        if (error)
                return error;
        flag = O_NONBLOCK;
#ifdef __sparc__
        /* SunOS compatibility item. */
        if (O_NONBLOCK != O_NDELAY)
                flag |= O_NDELAY;
#endif
        if (on)
                filp->f_flags |= flag;
        else
                filp->f_flags &= ~flag;
        return error;
}

static int ioctl_fioasync(unsigned int fd, struct file *filp,
                          int __user *argp)
{
        unsigned int flag;
        int on, error;

        error = get_user(on, argp);
        if (error)
                return error;
        flag = on ? FASYNC : 0;

        /* Did FASYNC state change ? */
        if ((flag ^ filp->f_flags) & FASYNC) {
                if (filp->f_op && filp->f_op->fasync)
                        error = filp->f_op->fasync(fd, filp, on);
                else
                        error = -ENOTTY;
        }
        if (error)
                return error;

        if (on)
                filp->f_flags |= FASYNC;
        else
                filp->f_flags &= ~FASYNC;
        return error;
}

/*
 * When you add any new common ioctls to the switches above and below
 * please update compat_sys_ioctl() too.
 *
 * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
 * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
 */
int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
             unsigned long arg)
{
        int error = 0;
        int __user *argp = (int __user *)arg;

        switch (cmd) {
        case FIOCLEX:
                set_close_on_exec(fd, 1);
                break;

        case FIONCLEX:
                set_close_on_exec(fd, 0);
                break;

        case FIONBIO:
                /* BKL needed to avoid races tweaking f_flags */
                lock_kernel();
                error = ioctl_fionbio(filp, argp);
                unlock_kernel();
                break;

        case FIOASYNC:
                /* BKL needed to avoid races tweaking f_flags */
                lock_kernel();
                error = ioctl_fioasync(fd, filp, argp);
                unlock_kernel();
                break;

        case FIOQSIZE:
                if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) ||
                    S_ISREG(filp->f_path.dentry->d_inode->i_mode) ||
                    S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) {
                        loff_t res =
                                inode_get_bytes(filp->f_path.dentry->d_inode);
                        error = copy_to_user((loff_t __user *)arg, &res,
                                             sizeof(res)) ? -EFAULT : 0;
                } else
                        error = -ENOTTY;
                break;
        default:
                if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
                        error = file_ioctl(filp, cmd, arg);
                else
                        error = vfs_ioctl(filp, cmd, arg);
                break;
        }
        return error;
}

SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
{
        struct file *filp;
        int error = -EBADF;
        int fput_needed;

        filp = fget_light(fd, &fput_needed);
        if (!filp)
                goto out;

        error = security_file_ioctl(filp, cmd, arg);
        if (error)
                goto out_fput;

        error = do_vfs_ioctl(filp, fd, cmd, arg);
 out_fput:
        fput_light(filp, fput_needed);
 out:
        return error;
}