root/fs/xiafs/dir.c

/* [previous][next][first][last][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. xiafs_dir_read
  2. xiafs_readdir

   1 /*
   2  *  linux/fs/xiafs/dir.c
   3  *  
   4  *  Copyright (C) Q. Frank Xia, 1993.
   5  *  
   6  *  Based on Linus' minix/dir.c
   7  *  Copyright (C) Linus Torvalds, 1991, 1992.
   8  *
   9  *  This software may be redistributed per Linux Copyright.
  10  */
  11 
  12 #ifdef MODULE
  13 #include <linux/module.h>
  14 #endif
  15 
  16 #include <asm/segment.h>
  17 #include <linux/sched.h>
  18 #include <linux/errno.h>
  19 #include <linux/kernel.h>
  20 #include <linux/fs.h>
  21 #include <linux/xia_fs.h>
  22 #include <linux/stat.h>
  23 
  24 #include "xiafs_mac.h"
  25 
  26 #define NAME_OFFSET(de) ((int) ((de)->d_name - (char *) (de)))
  27 #define ROUND_UP(x) (((x)+3) & ~3)
  28 
  29 static int xiafs_dir_read(struct inode *, struct file *, char *, int);
  30 static int xiafs_readdir(struct inode *, struct file *, struct dirent *, int);
  31 
  32 static struct file_operations xiafs_dir_operations = {
  33     NULL,               /* lseek - default */
  34     xiafs_dir_read,     /* read */
  35     NULL,               /* write - bad */
  36     xiafs_readdir,      /* readdir */
  37     NULL,               /* select - default */
  38     NULL,               /* ioctl - default */
  39     NULL,               /* mmap */
  40     NULL,               /* no special open code */
  41     NULL,               /* no special release code */
  42     file_fsync          /* default fsync */
  43 };
  44 
  45 /*
  46  * directories can handle most operations...
  47  */
  48 struct inode_operations xiafs_dir_inode_operations = {
  49     &xiafs_dir_operations,      /* default directory file-ops */
  50     xiafs_create,                       /* create */
  51     xiafs_lookup,                       /* lookup */
  52     xiafs_link,                 /* link */
  53     xiafs_unlink,                       /* unlink */
  54     xiafs_symlink,              /* symlink */
  55     xiafs_mkdir,                        /* mkdir */
  56     xiafs_rmdir,                        /* rmdir */
  57     xiafs_mknod,                        /* mknod */
  58     xiafs_rename,                       /* rename */
  59     NULL,                       /* readlink */
  60     NULL,                       /* follow_link */
  61     NULL,                       /* bmap */
  62     xiafs_truncate,             /* truncate */
  63     NULL                        /* permission */
  64 };
  65 
  66 static int xiafs_dir_read(struct inode * inode, 
     /* [previous][next][first][last][top][bottom][index][help] */
  67                         struct file * filp, char * buf, int count)
  68 {
  69   return -EISDIR;
  70 }
  71 
  72 static int xiafs_readdir(struct inode * inode, 
     /* [previous][next][first][last][top][bottom][index][help] */
  73                        struct file * filp, struct dirent * dirent, int count)
  74 {
  75     u_int offset, i,ret;
  76     struct buffer_head * bh;
  77     struct xiafs_direct * de;
  78 
  79     if (!inode || !inode->i_sb || !S_ISDIR(inode->i_mode))
  80         return -EBADF;
  81     if (inode->i_size & (XIAFS_ZSIZE(inode->i_sb) - 1) )
  82         return -EBADF;
  83     ret = 0;
  84     while (!ret && filp->f_pos < inode->i_size) {
  85         offset = filp->f_pos & (XIAFS_ZSIZE(inode->i_sb) - 1);
  86         bh = xiafs_bread(inode, filp->f_pos >> XIAFS_ZSIZE_BITS(inode->i_sb),0);
  87         if (!bh) {
  88             filp->f_pos += XIAFS_ZSIZE(inode->i_sb)-offset;
  89             continue;
  90         }
  91         for (i = 0; i < XIAFS_ZSIZE(inode->i_sb) && i < offset; ) {
  92             de = (struct xiafs_direct *) (bh->b_data + i);
  93             if (!de->d_rec_len)
  94                 break;
  95             i += de->d_rec_len;
  96         }
  97         offset = i;
  98         de = (struct xiafs_direct *) (offset + bh->b_data);
  99         
 100         while (!ret && offset < XIAFS_ZSIZE(inode->i_sb) && filp->f_pos < inode->i_size) {
 101             if (de->d_ino > inode->i_sb->u.xiafs_sb.s_ninodes ||
 102                 de->d_rec_len < 12 || 
 103                 (char *)de+de->d_rec_len > XIAFS_ZSIZE(inode->i_sb)+bh->b_data ||
 104                 de->d_name_len < 1 || de->d_name_len + 8 > de->d_rec_len ||
 105                 de->d_name_len > _XIAFS_NAME_LEN ||
 106                 de->d_name[de->d_name_len] ) {
 107                 printk("XIA-FS: bad directory entry (%s %d)\n", WHERE_ERR);
 108                 brelse(bh);
 109                 return 0;
 110             }  
 111             offset += de->d_rec_len;
 112             filp->f_pos += de->d_rec_len;
 113             if (de->d_ino) {
 114                 for (i = 0; i < de->d_name_len ; i++)
 115                     put_fs_byte(de->d_name[i],i+dirent->d_name);
 116                 put_fs_byte(0,i+dirent->d_name);
 117                 put_fs_long(de->d_ino,&dirent->d_ino);
 118                 put_fs_word(i,&dirent->d_reclen);
 119                 if (!IS_RDONLY (inode)) {
 120                     inode->i_atime=CURRENT_TIME;                    
 121                     inode->i_dirt=1;
 122                 }
 123                 ret = ROUND_UP(NAME_OFFSET(dirent)+i+1);
 124                 break;
 125             }
 126             de = (struct xiafs_direct *) (offset + bh->b_data);
 127         }
 128         brelse(bh);
 129         if (offset > XIAFS_ZSIZE(inode->i_sb)) {
 130             printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
 131             return 0;
 132         }
 133     }
 134     if (!IS_RDONLY (inode)) {
 135         inode->i_atime=CURRENT_TIME;                
 136         inode->i_dirt=1;
 137     }
 138     return ret;
 139 }

/* [previous][next][first][last][top][bottom][index][help] */