fs/sysv/dir.c

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 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 intsysv_dir_read(struct inode * inode,struct file * filp,char* buf,int count)
 29 {
 30 return-EISDIR;
 31 }
 32
 33 static intsysv_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 intsysv_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 return0;
 106 }
 107 }
 108  offset += SYSV_DIRSIZE;
 109  filp->f_pos += SYSV_DIRSIZE;
 110 }
 111 brelse(bh);
 112 }
 113 return0;
 114 }