* better

[mascara-docs.git] / i386 / linux-2.3.21 / fs / udf / file.c

/*
 * file.c
 *
 * PURPOSE
 *  File handling routines for the OSTA-UDF(tm) filesystem.
 *
 * CONTACTS
 *  E-mail regarding any portion of the Linux UDF file system should be
 *  directed to the development team mailing list (run by majordomo):
 *    linux_udf@hootie.lvld.hp.com
 *
 * COPYRIGHT
 *  This file is distributed under the terms of the GNU General Public
 *  License (GPL). Copies of the GPL can be obtained from:
 *    ftp://prep.ai.mit.edu/pub/gnu/GPL
 *  Each contributing author retains all rights to their own work.
 *
 *  (C) 1998-1999 Dave Boynton
 *  (C) 1998-1999 Ben Fennema
 *  (C) 1999 Stelias Computing Inc
 *
 * HISTORY
 *
 *  10/02/98 dgb  Attempt to integrate into udf.o
 *  10/07/98      Switched to using generic_readpage, etc., like isofs
 *                And it works!
 *  12/06/98 blf  Added udf_file_read. uses generic_file_read for all cases but
 *                ICB_FLAG_AD_IN_ICB.
 *  04/06/99      64 bit file handling on 32 bit systems taken from ext2 file.c
 *  05/12/99      Preliminary file write support
 */

#include "udfdecl.h"
#include <linux/fs.h>
#include <linux/udf_fs.h>
#include <asm/uaccess.h>
#include <linux/kernel.h>
#include <linux/string.h> /* memset */
#include <linux/errno.h>
#include <linux/locks.h>

#include "udf_i.h"
#include "udf_sb.h"

#define NBUF    32

typedef void * poll_table; 

static long long udf_file_llseek(struct file *, long long, int);
static ssize_t udf_file_read_adinicb (struct file *, char *, size_t, loff_t *);
static ssize_t udf_file_write (struct file *, const char *, size_t, loff_t *);
#if BITS_PER_LONG < 64
static int udf_open_file(struct inode *, struct file *);
#endif
static int udf_release_file(struct inode *, struct file *);

static struct file_operations udf_file_operations = {
        udf_file_llseek,        /* llseek */
        generic_file_read,      /* read */
        udf_file_write,         /* write */
        NULL,                           /* readdir */
        NULL,                           /* poll */
        udf_ioctl,                      /* ioctl */
        generic_file_mmap,      /* mmap */
#if BITS_PER_LONG == 64
        NULL,                           /* open */
#else
        udf_open_file,          /* open */
#endif
        NULL,                           /* flush */
        udf_release_file,       /* release */
        udf_sync_file,          /* fsync */
        NULL,                           /* fasync */
        NULL,                           /* check_media_change */
        NULL,                           /* revalidate */
        NULL                            /* lock */
};

struct inode_operations udf_file_inode_operations = {
        &udf_file_operations,
        NULL,                                   /* create */
        NULL,                                   /* lookup */
        NULL,                                   /* link */
        NULL,                                   /* unlink */
        NULL,                                   /* symlink */
        NULL,                                   /* mkdir */
        NULL,                                   /* rmdir */
        NULL,                                   /* mknod */
        NULL,                                   /* rename */
        NULL,                                   /* readlink */
        NULL,                                   /* follow_link */
        udf_get_block,                  /* get_block */
        block_read_full_page,   /* readpage */
        block_write_full_page,  /* writepage */
        block_flushpage,                /* flushpage */
#ifdef CONFIG_UDF_RW
        udf_truncate,                   /* truncate */
#else
        NULL,                                   /* truncate */
#endif
        NULL,                                   /* permission */
        NULL,                                   /* smap */
        NULL                                    /* revalidate */
};

static struct file_operations udf_file_operations_adinicb = {
        udf_file_llseek,        /* llseek */
        udf_file_read_adinicb,/* read */
        udf_file_write,         /* write */
        NULL,                           /* readdir */
        NULL,                           /* poll */
        udf_ioctl,                      /* ioctl */
        NULL,                           /* mmap */
        NULL,                           /* open */
        NULL,                           /* flush */
        udf_release_file,       /* release */
        udf_sync_file,          /* fsync */
        NULL,                           /* fasync */
        NULL,                           /* check_media_change */
        NULL,                           /* revalidate */
        NULL                            /* lock */
};

struct inode_operations udf_file_inode_operations_adinicb = {
        &udf_file_operations_adinicb,
        NULL,                                   /* create */
        NULL,                                   /* lookup */
        NULL,                                   /* link */
        NULL,                                   /* unlink */
        NULL,                                   /* symlink */
        NULL,                                   /* mkdir */
        NULL,                                   /* rmdir */
        NULL,                                   /* mknod */
        NULL,                                   /* rename */
        NULL,                                   /* readlink */
        NULL,                                   /* follow_link */
        udf_get_block,                  /* get_block */
        block_read_full_page,   /* readpage */
        block_write_full_page,  /* writepage */
        block_flushpage,                /* flushpage */
#ifdef CONFIG_UDF_RW
        udf_truncate,                   /* truncate */
#else
        NULL,                                   /* truncate */
#endif
        NULL,                                   /* permission */
        NULL,                                   /* smap */
        NULL                                    /* revalidate */
};

/*
 * Make sure the offset never goes beyond the 32-bit mark..
 */
static long long udf_file_llseek(struct file * file, long long offset, int origin)
{
        struct inode * inode = file->f_dentry->d_inode;

        switch (origin)
        {
                case 2:
                {
                        offset += inode->i_size;
                        break;
                }
                case 1:
                {
                        offset += file->f_pos;
                        break;
                }
        }
#if BITS_PER_LONG < 64
        if (((unsigned long long) offset >> 32) != 0)
        {
                return -EINVAL;
        }
#endif
        if (offset != file->f_pos)
        {
                file->f_pos = offset;
                file->f_reada = 0;
                file->f_version = ++event;
        }
        return offset;
}

static inline void remove_suid(struct inode * inode)
{
        unsigned int mode;

        /* set S_IGID if S_IXGRP is set, and always set S_ISUID */
        mode = (inode->i_mode & S_IXGRP)*(S_ISGID/S_IXGRP) | S_ISUID;

        /* was any of the uid bits set? */
        mode &= inode->i_mode;
        if (mode && !capable(CAP_FSETID))
        {
                inode->i_mode &= ~mode;
                mark_inode_dirty(inode);
        }
}

static ssize_t udf_file_write(struct file * file, const char * buf,
        size_t count, loff_t *ppos)
{
        ssize_t retval;
        struct inode *inode = file->f_dentry->d_inode;
        remove_suid(inode);

        if (UDF_I_ALLOCTYPE(inode) == ICB_FLAG_AD_IN_ICB)
        {
                int i, err;
                struct buffer_head *bh;

                if ((bh = udf_expand_adinicb(inode, &i, 0, &err)))
                        udf_release_data(bh);
        }

        retval = generic_file_write(file, buf, count, ppos, block_write_partial_page);

        if (retval > 0)
        {
                inode->i_ctime = inode->i_mtime = CURRENT_TIME;
                UDF_I_UCTIME(inode) = UDF_I_UMTIME(inode) = CURRENT_UTIME;
        }
        mark_inode_dirty(inode);
        return retval;
}

/*
 * udf_file_read
 *
 * PURPOSE
 *      Read from an open file.
 *
 * DESCRIPTION
 *      Optional - sys_read() will return -EINVAL if this routine is not
 *      available.
 *
 *      Refer to sys_read() in fs/read_write.c
 *      sys_read() -> .
 *
 *      Note that you can use generic_file_read() instead, which requires that
 *      udf_readpage() be available, but you can use generic_readpage(), which
 *      requires that udf_block_map() be available. Reading will then be done by
 *      memory-mapping the file a page at a time. This is not suitable for
 *      devices that don't handle read-ahead [example: CD-R/RW that may have
 *      blank sectors that shouldn't be read].
 *
 *      Refer to generic_file_read() in mm/filemap.c and to generic_readpage()
 *      in fs/buffer.c
 *
 *      Block devices can use block_read() instead. Refer to fs/block_dev.c
 *
 * PRE-CONDITIONS
 *      inode                   Pointer to inode to read from (never NULL).
 *      filp                    Pointer to file to read from (never NULL).
 *      buf                     Point to read buffer (validated).
 *      bufsize                 Size of read buffer.
 *
 * POST-CONDITIONS
 *      <return>                Bytes read (>=0) or an error code (<0) that
 *                              sys_read() will return.
 *
 * HISTORY
 *      July 1, 1997 - Andrew E. Mileski
 *      Written, tested, and released.
 */
static ssize_t udf_file_read_adinicb(struct file * filp, char * buf,
        size_t bufsize, loff_t * loff)
{
        struct inode *inode = filp->f_dentry->d_inode;
        Uint32 size, left, pos, block;
        struct buffer_head *bh = NULL;

        size = inode->i_size;
        if (*loff > size)
                left = 0;
        else
                left = size - *loff;
        if (left > bufsize)
                left = bufsize;

        if (left <= 0)
                return 0;

        pos = *loff + UDF_I_EXT0OFFS(inode);
        block = udf_block_map(inode, 0);
        if (!(bh = udf_tread(inode->i_sb,
                udf_get_lb_pblock(inode->i_sb, UDF_I_LOCATION(inode), 0),
                inode->i_sb->s_blocksize)))
        {
                return 0;
        }
        if (!copy_to_user(buf, bh->b_data + pos, left))
                *loff += left;
        else
                return -EFAULT;

        return left;
}

/*
 * udf_ioctl
 *
 * PURPOSE
 *      Issue an ioctl.
 *
 * DESCRIPTION
 *      Optional - sys_ioctl() will return -ENOTTY if this routine is not
 *      available, and the ioctl cannot be handled without filesystem help.
 *
 *      sys_ioctl() handles these ioctls that apply only to regular files:
 *              FIBMAP [requires udf_block_map()], FIGETBSZ, FIONREAD
 *      These ioctls are also handled by sys_ioctl():
 *              FIOCLEX, FIONCLEX, FIONBIO, FIOASYNC
 *      All other ioctls are passed to the filesystem.
 *
 *      Refer to sys_ioctl() in fs/ioctl.c
 *      sys_ioctl() -> .
 *
 * PRE-CONDITIONS
 *      inode                   Pointer to inode that ioctl was issued on.
 *      filp                    Pointer to file that ioctl was issued on.
 *      cmd                     The ioctl command.
 *      arg                     The ioctl argument [can be interpreted as a
 *                              user-space pointer if desired].
 *
 * POST-CONDITIONS
 *      <return>                Success (>=0) or an error code (<=0) that
 *                              sys_ioctl() will return.
 *
 * HISTORY
 *      July 1, 1997 - Andrew E. Mileski
 *      Written, tested, and released.
 */
int udf_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
        unsigned long arg)
{
        int result=-1;
        int size;
        struct buffer_head *bh = NULL;
        struct FileEntry *fe;
        Uint16 ident;

        if ( permission(inode, MAY_READ) != 0 )
        {
                udf_debug("no permission to access inode %lu\n",
                                                inode->i_ino);
                return -EPERM;
        }

        if ( !arg )
        {
                udf_debug("invalid argument to udf_ioctl\n");
                return -EINVAL;
        }

        /* first, do ioctls that don't need to udf_read */
        switch (cmd)
        {
                case UDF_GETVOLIDENT:
                        if ( (result == verify_area(VERIFY_WRITE, (char *)arg, 32)) == 0)
                                result = copy_to_user((char *)arg, UDF_SB_VOLIDENT(inode->i_sb), 32);
                        return result;

        }

        /* ok, we need to read the inode */
        bh = udf_read_ptagged(inode->i_sb, UDF_I_LOCATION(inode), 0, &ident);

        if (!bh || ident != TID_FILE_ENTRY)
        {
                udf_debug("bread failed (ino=%ld) or ident (%d) != TID_FILE_ENTRY",
                        inode->i_ino, ident);
                return -EFAULT;
        }

        fe = (struct FileEntry *)bh->b_data;
        size = le32_to_cpu(fe->lengthExtendedAttr);

        switch (cmd) 
        {
                case UDF_GETEASIZE:
                        if ( (result = verify_area(VERIFY_WRITE, (char *)arg, 4)) == 0) 
                                result= put_user(size, (int *)arg);
                        break;

                case UDF_GETEABLOCK:
                        if ( (result = verify_area(VERIFY_WRITE, (char *)arg, size)) == 0) 
                                result= copy_to_user((char *)arg, fe->extendedAttr, size);
                        break;

                default:
                        udf_debug("ino=%ld, cmd=%d\n", inode->i_ino, cmd);
                        break;
        }

        udf_release_data(bh);
        return result;
}

/*
 * udf_release_file
 *
 * PURPOSE
 *  Called when all references to the file are closed
 *
 * DESCRIPTION
 *  Discard prealloced blocks
 *
 * HISTORY
 *
 */
static int udf_release_file(struct inode * inode, struct file * filp)
{
        if (filp->f_mode & FMODE_WRITE)
                udf_discard_prealloc(inode);
        return 0;
}

#if BITS_PER_LONG < 64
/*
 * udf_open_file
 *
 * PURPOSE
 *  Called when an inode is about to be open.
 *
 * DESCRIPTION
 *  Use this to disallow opening RW large files on 32 bit systems.
 *
 * HISTORY
 *
 */
static int udf_open_file(struct inode * inode, struct file * filp)
{
        if (inode->i_size == (Uint32)-1 && (filp->f_mode & FMODE_WRITE))
                return -EFBIG;
        return 0;
}
#endif