fs/sysv/dir.c

/* */
This source file includes following definitions.
sysv_dir_read
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 #include <linux/string.h>
  27 
  28 static int sysv_dir_read(struct inode * inode, struct file * filp, char * buf, int count)
     /*  */
  29 {
  30         return -EISDIR;
  31 }
  32 
  33 static int sysv_readdir(struct inode *, struct file *, void *, filldir_t);
  34 
  35 static struct file_operations sysv_dir_operations = {
  36         NULL,                   /* lseek - default */
  37         sysv_dir_read,          /* read */
  38         NULL,                   /* write - bad */
  39         sysv_readdir,           /* readdir */
  40         NULL,                   /* select - default */
  41         NULL,                   /* ioctl - default */
  42         NULL,                   /* mmap */
  43         NULL,                   /* no special open code */
  44         NULL,                   /* no special release code */
  45         file_fsync              /* default fsync */
  46 };
  47 
  48 /*
  49  * directories can handle most operations...
  50  */
  51 struct inode_operations sysv_dir_inode_operations = {
  52         &sysv_dir_operations,   /* default directory file-ops */
  53         sysv_create,            /* create */
  54         sysv_lookup,            /* lookup */
  55         sysv_link,              /* link */
  56         sysv_unlink,            /* unlink */
  57         sysv_symlink,           /* symlink */
  58         sysv_mkdir,             /* mkdir */
  59         sysv_rmdir,             /* rmdir */
  60         sysv_mknod,             /* mknod */
  61         sysv_rename,            /* rename */
  62         NULL,                   /* readlink */
  63         NULL,                   /* follow_link */
  64         NULL,                   /* bmap */
  65         sysv_truncate,          /* truncate */
  66         NULL                    /* permission */
  67 };
  68 
  69 static int sysv_readdir(struct inode * inode, struct file * filp,
     /*  */
  70         void * dirent, filldir_t filldir)
  71 {
  72         struct super_block * sb;
  73         unsigned int offset,i;
  74         struct buffer_head * bh;
  75         char* bh_data;
  76         struct sysv_dir_entry * de, sde;
  77 
  78         if (!inode || !(sb = inode->i_sb) || !S_ISDIR(inode->i_mode))
  79                 return -EBADF;
  80         if ((unsigned long)(filp->f_pos) % SYSV_DIRSIZE)
  81                 return -EBADF;
  82         while (filp->f_pos < inode->i_size) {
  83                 offset = filp->f_pos & sb->sv_block_size_1;
  84                 bh = sysv_file_bread(inode, filp->f_pos >> sb->sv_block_size_bits, 0);
  85                 if (!bh) {
  86                         filp->f_pos += sb->sv_block_size - offset;
  87                         continue;
  88                 }
  89                 bh_data = bh->b_data;
  90                 while (offset < sb->sv_block_size && filp->f_pos < inode->i_size) {
  91                         de = (struct sysv_dir_entry *) (offset + bh_data);
  92                         if (de->inode) {
  93                                 /* Copy the directory entry first, because the directory
  94                                  * might be modified while we sleep in filldir()...
  95                                  */
  96                                 memcpy(&sde, de, sizeof(struct sysv_dir_entry));
  97 
  98                                 if (sde.inode > inode->i_sb->sv_ninodes)
  99                                         printk("sysv_readdir: Bad inode number on dev 0x%04x, ino %ld, offset 0x%04lx: %d is out of range\n",
 100                                                 inode->i_dev, inode->i_ino, (off_t) filp->f_pos, sde.inode);
 101 
 102                                 i = strnlen(sde.name, SYSV_NAMELEN);
 103                                 if (filldir(dirent, sde.name, i, filp->f_pos, sde.inode) < 0) {
 104                                         brelse(bh);
 105                                         return 0;
 106                                 }
 107                         }
 108                         offset += SYSV_DIRSIZE;
 109                         filp->f_pos += SYSV_DIRSIZE;
 110                 }
 111                 brelse(bh);
 112         }
 113         return 0;
 114 }
/* */
root/fs/sysv/dir.c

DEFINITIONS
