fs/ext/dir.c

/* */
This source file includes following definitions.
ext_dir_read
ext_readdir
   1 /*
   2  *  linux/fs/ext/dir.c
   3  *
   4  *  Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
   5  *
   6  *  from
   7  *
   8  *  linux/fs/minix/dir.c
   9  *
  10  *  Copyright (C) 1991, 1992 Linus Torvalds
  11  *
  12  *  ext directory handling functions
  13  */
  14 
  15 #include <asm/segment.h>
  16 
  17 #include <linux/errno.h>
  18 #include <linux/kernel.h>
  19 #include <linux/fs.h>
  20 #include <linux/ext_fs.h>
  21 #include <linux/stat.h>
  22 
  23 #define NAME_OFFSET(de) ((int) ((de)->d_name - (char *) (de)))
  24 #define ROUND_UP(x) (((x)+3) & ~3)
  25 
  26 static int ext_dir_read(struct inode * inode, struct file * filp, char * buf, int count)
     /*  */
  27 {
  28         return -EISDIR;
  29 }
  30 
  31 static int ext_readdir(struct inode *, struct file *, struct dirent *, int);
  32 
  33 static struct file_operations ext_dir_operations = {
  34         NULL,                   /* lseek - default */
  35         ext_dir_read,           /* read */
  36         NULL,                   /* write - bad */
  37         ext_readdir,            /* readdir */
  38         NULL,                   /* select - default */
  39         NULL,                   /* ioctl - default */
  40         NULL,                   /* mmap */
  41         NULL,                   /* no special open code */
  42         NULL,                   /* no special release code */
  43         file_fsync              /* fsync */
  44 };
  45 
  46 /*
  47  * directories can handle most operations...
  48  */
  49 struct inode_operations ext_dir_inode_operations = {
  50         &ext_dir_operations,    /* default directory file-ops */
  51         ext_create,             /* create */
  52         ext_lookup,             /* lookup */
  53         ext_link,               /* link */
  54         ext_unlink,             /* unlink */
  55         ext_symlink,            /* symlink */
  56         ext_mkdir,              /* mkdir */
  57         ext_rmdir,              /* rmdir */
  58         ext_mknod,              /* mknod */
  59         ext_rename,             /* rename */
  60         NULL,                   /* readlink */
  61         NULL,                   /* follow_link */
  62         NULL,                   /* bmap */
  63         ext_truncate,           /* truncate */
  64         NULL                    /* permission */
  65 };
  66 
  67 static int ext_readdir(struct inode * inode, struct file * filp,
     /*  */
  68         struct dirent * dirent, int count)
  69 {
  70         unsigned int i;
  71         unsigned int ret;
  72         off_t offset;
  73         char c;
  74         struct buffer_head * bh;
  75         struct ext_dir_entry * de;
  76 
  77         if (!inode || !S_ISDIR(inode->i_mode))
  78                 return -EBADF;
  79         if ((filp->f_pos & 7) != 0)
  80                 return -EBADF;
  81         ret = 0;
  82         while (!ret && filp->f_pos < inode->i_size) {
  83                 offset = filp->f_pos & 1023;
  84                 bh = ext_bread(inode,(filp->f_pos)>>BLOCK_SIZE_BITS,0);
  85                 if (!bh) {
  86                         filp->f_pos += 1024-offset;
  87                         continue;
  88                 }
  89                 for (i = 0; i < 1024 && i < offset; ) {
  90                         de = (struct ext_dir_entry *) (bh->b_data + i);
  91                         if (!de->rec_len)
  92                                 break;
  93                         i += de->rec_len;
  94                 }
  95                 offset = i;
  96                 de = (struct ext_dir_entry *) (offset + bh->b_data);
  97                 while (!ret && offset < 1024 && filp->f_pos < inode->i_size) {
  98                         if (de->rec_len < 8 || de->rec_len % 8 != 0 ||
  99                             de->rec_len < de->name_len + 8 ||
 100                             (de->rec_len + (off_t) filp->f_pos - 1) / 1024 > ((off_t) filp->f_pos / 1024)) {
 101                                 printk ("ext_readdir: bad dir entry, skipping\n");
 102                                 printk ("dev=%d, dir=%ld, offset=%ld, rec_len=%d, name_len=%d\n",
 103                                         inode->i_dev, inode->i_ino, offset, de->rec_len, de->name_len);
 104                                 filp->f_pos += 1024-offset;
 105                                 if (filp->f_pos > inode->i_size)
 106                                         filp->f_pos = inode->i_size;
 107                                 continue;
 108                         }
 109                         offset += de->rec_len;
 110                         filp->f_pos += de->rec_len;
 111                         if (de->inode) {
 112                                 for (i = 0; i < de->name_len; i++)
 113                                         if ((c = de->name[i]) != 0)
 114                                                 put_fs_byte(c,i+dirent->d_name);
 115                                         else
 116                                                 break;
 117                                 if (i) {
 118                                         put_fs_long(de->inode,&dirent->d_ino);
 119                                         put_fs_byte(0,i+dirent->d_name);
 120                                         put_fs_word(i,&dirent->d_reclen);
 121                                         ret = ROUND_UP(NAME_OFFSET(dirent)+i+1);
 122                                         break;
 123                                 }
 124                         }
 125                         de = (struct ext_dir_entry *) ((char *) de 
 126                                 + de->rec_len);
 127                 }
 128                 brelse(bh);
 129         }
 130         return ret;
 131 }
/* */
root/fs/ext/dir.c

DEFINITIONS
