i386/linux/linux-0.99/fs/msdos/dir.c

   1 /*
   2  *  linux/fs/msdos/dir.c
   3  *
   4  *  Written 1992,1993 by Werner Almesberger
   5  *
   6  *  MS-DOS directory handling functions
   7  */
   8
   9 #include <asm/segment.h>
  10
  11 #include <linux/fs.h>
  12 #include <linux/msdos_fs.h>
  13 #include <linux/errno.h>
  14 #include <linux/stat.h>
  15
  16
  17 static int msdos_dir_read(struct inode * inode,struct file * filp, char * buf,int count)
  18 {
  19         return -EISDIR;
  20 }
  21
  22 static int msdos_readdir(struct inode *inode,struct file *filp,
  23     struct dirent *dirent,int count);
  24
  25
  26 static struct file_operations msdos_dir_operations = {
  27         NULL,                   /* lseek - default */
  28         msdos_dir_read,         /* read */
  29         NULL,                   /* write - bad */
  30         msdos_readdir,          /* readdir */
  31         NULL,                   /* select - default */
  32         NULL,                   /* ioctl - default */
  33         NULL,                   /* mmap */
  34         NULL,                   /* no special open code */
  35         NULL,                   /* no special release code */
  36         file_fsync              /* fsync */
  37 };
  38
  39 struct inode_operations msdos_dir_inode_operations = {
  40         &msdos_dir_operations,  /* default directory file-ops */
  41         msdos_create,           /* create */
  42         msdos_lookup,           /* lookup */
  43         NULL,                   /* link */
  44         msdos_unlink,           /* unlink */
  45         NULL,                   /* symlink */
  46         msdos_mkdir,            /* mkdir */
  47         msdos_rmdir,            /* rmdir */
  48         NULL,                   /* mknod */
  49         msdos_rename,           /* rename */
  50         NULL,                   /* readlink */
  51         NULL,                   /* follow_link */
  52         msdos_bmap,             /* bmap */
  53         NULL,                   /* truncate */
  54         NULL                    /* permission */
  55 };
  56
  57 static int msdos_readdir(struct inode *inode,struct file *filp,
  58     struct dirent *dirent,int count)
  59 {
  60         int ino,i,i2,last;
  61         char c,*walk;
  62         struct buffer_head *bh;
  63         struct msdos_dir_entry *de;
  64
  65         if (!inode || !S_ISDIR(inode->i_mode)) return -EBADF;
  66         if (inode->i_ino == MSDOS_ROOT_INO) {
  67 /* Fake . and .. for the root directory. */
  68                 if (filp->f_pos == 2) filp->f_pos = 0;
  69                 else if (filp->f_pos < 2) {
  70                                 walk = filp->f_pos++ ? ".." : ".";
  71                                 for (i = 0; *walk; walk++)
  72                                         put_fs_byte(*walk,dirent->d_name+i++);
  73                                 put_fs_long(MSDOS_ROOT_INO,&dirent->d_ino);
  74                                 put_fs_byte(0,dirent->d_name+i);
  75                                 put_fs_word(i,&dirent->d_reclen);
  76                                 return i;
  77                         }
  78         }
  79         if (filp->f_pos & (sizeof(struct msdos_dir_entry)-1)) return -ENOENT;
  80         bh = NULL;
  81         while ((ino = msdos_get_entry(inode,&filp->f_pos,&bh,&de)) > -1) {
  82                 if (!IS_FREE(de->name) && !(de->attr & ATTR_VOLUME)) {
  83                         for (i = last = 0; i < 8; i++) {
  84                                 if (!(c = de->name[i])) break;
  85                                 if (c >= 'A' && c <= 'Z') c += 32;
  86                                 if (c != ' ') last = i+1;
  87                                 put_fs_byte(c,i+dirent->d_name);
  88                         }
  89                         i = last;
  90                         put_fs_byte('.',i+dirent->d_name);
  91                         i++;
  92                         for (i2 = 0; i2 < 3; i2++) {
  93                                 if (!(c = de->ext[i2])) break;
  94                                 if (c >= 'A' && c <= 'Z') c += 32;
  95                                 if (c != ' ') last = i+1;
  96                                 put_fs_byte(c,i+dirent->d_name);
  97                                 i++;
  98                         }
  99                         if ((i = last) != 0) {
 100                                 if (!strcmp(de->name,MSDOS_DOT))
 101                                         ino = inode->i_ino;
 102                                 else if (!strcmp(de->name,MSDOS_DOTDOT))
 103                                                 ino = msdos_parent_ino(inode,0);
 104                                 put_fs_long(ino,&dirent->d_ino);
 105                                 put_fs_byte(0,i+dirent->d_name);
 106                                 put_fs_word(i,&dirent->d_reclen);
 107                                 brelse(bh);
 108                                 return i;
 109                         }
 110                 }
 111         }
 112         if (bh) brelse(bh);
 113         return 0;
 114 }