fs/sysv/dir.c

/* */
This source file includes following definitions.
sysv_dir_read
sysv_readdir1
sysv_readdir
   1 /*
   2  *  linux/fs/sysv/dir.c
   3  *
   4  *  minix/dir.c
   5  *  Copyright (C) 1991, 1992  Linus Torvalds
   6  *
   7  *  coh/dir.c
   8  *  Copyright (C) 1993  Pascal Haible, Bruno Haible
   9  *
  10  *  sysv/dir.c
  11  *  Copyright (C) 1993  Bruno Haible
  12  *
  13  *  SystemV/Coherent directory handling functions
  14  */
  15 
  16 #ifdef MODULE
  17 #include <linux/module.h>
  18 #endif
  19 
  20 #include <asm/segment.h>
  21 
  22 #include <linux/errno.h>
  23 #include <linux/fs.h>
  24 #include <linux/sysv_fs.h>
  25 #include <linux/stat.h>
  26 
  27 #define NAME_OFFSET(de) ((int) ((de)->d_name - (char *) (de)))
  28 #define ROUND_UP(x) (((x)+3) & ~3)
  29 
  30 static int sysv_dir_read(struct inode * inode, struct file * filp, char * buf, int count)
     /*  */
  31 {
  32         return -EISDIR;
  33 }
  34 
  35 static int sysv_readdir(struct inode *, struct file *, struct dirent *, int);
  36 
  37 static struct file_operations sysv_dir_operations = {
  38         NULL,                   /* lseek - default */
  39         sysv_dir_read,          /* read */
  40         NULL,                   /* write - bad */
  41         sysv_readdir,           /* readdir */
  42         NULL,                   /* select - default */
  43         NULL,                   /* ioctl - default */
  44         NULL,                   /* mmap */
  45         NULL,                   /* no special open code */
  46         NULL,                   /* no special release code */
  47         file_fsync              /* default fsync */
  48 };
  49 
  50 /*
  51  * directories can handle most operations...
  52  */
  53 struct inode_operations sysv_dir_inode_operations = {
  54         &sysv_dir_operations,   /* default directory file-ops */
  55         sysv_create,            /* create */
  56         sysv_lookup,            /* lookup */
  57         sysv_link,              /* link */
  58         sysv_unlink,            /* unlink */
  59         sysv_symlink,           /* symlink */
  60         sysv_mkdir,             /* mkdir */
  61         sysv_rmdir,             /* rmdir */
  62         sysv_mknod,             /* mknod */
  63         sysv_rename,            /* rename */
  64         NULL,                   /* readlink */
  65         NULL,                   /* follow_link */
  66         NULL,                   /* bmap */
  67         sysv_truncate,          /* truncate */
  68         NULL                    /* permission */
  69 };
  70 
  71 static int sysv_readdir1 (struct inode * inode, struct file * filp,
     /*  */
  72         struct dirent * dirent)
  73 {
  74         struct super_block * sb;
  75         unsigned int offset,i;
  76         char c;
  77         struct buffer_head * bh;
  78         char* bh_data;
  79         struct sysv_dir_entry * de;
  80 
  81         if (!inode || !(sb = inode->i_sb) || !S_ISDIR(inode->i_mode))
  82                 return -EBADF;
  83         if ((unsigned long)(filp->f_pos) % SYSV_DIRSIZE)
  84                 return -EBADF;
  85         while (filp->f_pos < inode->i_size) {
  86                 offset = filp->f_pos & sb->sv_block_size_1;
  87                 bh = sysv_file_bread(inode, filp->f_pos >> sb->sv_block_size_bits, 0);
  88                 if (!bh) {
  89                         filp->f_pos += sb->sv_block_size - offset;
  90                         continue;
  91                 }
  92                 bh_data = bh->b_data;
  93                 while (offset < sb->sv_block_size && filp->f_pos < inode->i_size) {
  94                         de = (struct sysv_dir_entry *) (offset + bh_data);
  95                         offset += SYSV_DIRSIZE;
  96                         filp->f_pos += SYSV_DIRSIZE;
  97                         if (de->inode) {
  98                                 struct sysv_dir_entry sde;
  99 
 100                                 /* Copy the directory entry first, because the directory
 101                                  * might be modified while we sleep in put_fs_byte...
 102                                  */
 103                                 memcpy(&sde, de, sizeof(struct sysv_dir_entry));
 104 
 105                                 for (i = 0; i < SYSV_NAMELEN; i++)
 106                                         if ((c = sde.name[i]) != 0)
 107                                                 put_fs_byte(c,i+dirent->d_name);
 108                                         else
 109                                                 break;
 110                                 if (i) {
 111                                         if (sde.inode > inode->i_sb->sv_ninodes)
 112                                                 printk("sysv_readdir: Bad inode number on dev 0x%04x, ino %ld, offset 0x%04lx: %d is out of range\n",
 113                                                         inode->i_dev, inode->i_ino, (off_t) filp->f_pos - SYSV_DIRSIZE, sde.inode);
 114                                         put_fs_long(sde.inode,&dirent->d_ino);
 115                                         put_fs_byte(0,i+dirent->d_name);
 116                                         put_fs_word(i,&dirent->d_reclen);
 117                                         brelse(bh);
 118                                         return ROUND_UP(NAME_OFFSET(dirent)+i+1);
 119                                 }
 120                         }
 121                 }
 122                 brelse(bh);
 123         }
 124         return 0;
 125 }
 126 
 127 static int sysv_readdir(struct inode * inode, struct file * filp,
     /*  */
 128         struct dirent * dirent, int count)
 129 {
 130         int retval, stored;
 131 
 132         /* compatibility */
 133         if (count==1)
 134                 return sysv_readdir1(inode,filp,dirent);
 135 
 136         stored = 0;
 137         while (count >= sizeof(struct dirent)) {
 138                 retval = sysv_readdir1(inode,filp,dirent);
 139                 if (retval < 0)
 140                         return retval;
 141                 if (!retval)
 142                         return stored;
 143                 dirent = (struct dirent *)((char *) dirent + retval);
 144                 stored += retval;
 145                 count -= retval;
 146         }
 147         return stored;
 148 }
/* */
root/fs/sysv/dir.c

DEFINITIONS
