fs/sysv/symlink.c

/* */
This source file includes following definitions.
sysv_follow_link
sysv_readlink
   1 /*
   2  *  linux/fs/sysv/symlink.c
   3  *
   4  *  minix/symlink.c
   5  *  Copyright (C) 1991, 1992  Linus Torvalds
   6  *
   7  *  coh/symlink.c
   8  *  Copyright (C) 1993  Pascal Haible, Bruno Haible
   9  *
  10  *  sysv/symlink.c
  11  *  Copyright (C) 1993  Bruno Haible
  12  *
  13  *  SystemV/Coherent symlink handling code
  14  */
  15 
  16 #include <linux/errno.h>
  17 #include <linux/sched.h>
  18 #include <linux/sysv_fs.h>
  19 #include <linux/stat.h>
  20 
  21 #include <asm/segment.h>
  22 
  23 static int sysv_readlink(struct inode *, char *, int);
  24 static int sysv_follow_link(struct inode *, struct inode *, int, int, struct inode **);
  25 
  26 /*
  27  * symlinks can't do much...
  28  */
  29 struct inode_operations sysv_symlink_inode_operations = {
  30         NULL,                   /* no file-operations */
  31         NULL,                   /* create */
  32         NULL,                   /* lookup */
  33         NULL,                   /* link */
  34         NULL,                   /* unlink */
  35         NULL,                   /* symlink */
  36         NULL,                   /* mkdir */
  37         NULL,                   /* rmdir */
  38         NULL,                   /* mknod */
  39         NULL,                   /* rename */
  40         sysv_readlink,          /* readlink */
  41         sysv_follow_link,       /* follow_link */
  42         NULL,                   /* readpage */
  43         NULL,                   /* writepage */
  44         NULL,                   /* bmap */
  45         NULL,                   /* truncate */
  46         NULL                    /* permission */
  47 };
  48 
  49 static int sysv_follow_link(struct inode * dir, struct inode * inode,
     /*  */
  50         int flag, int mode, struct inode ** res_inode)
  51 {
  52         int error;
  53         struct buffer_head * bh;
  54 
  55         *res_inode = NULL;
  56         if (!dir) {
  57                 dir = current->fs->root;
  58                 dir->i_count++;
  59         }
  60         if (!inode) {
  61                 iput(dir);
  62                 return -ENOENT;
  63         }
  64         if (!S_ISLNK(inode->i_mode)) {
  65                 iput(dir);
  66                 *res_inode = inode;
  67                 return 0;
  68         }
  69         if (current->link_count > 5) {
  70                 iput(inode);
  71                 iput(dir);
  72                 return -ELOOP;
  73         }
  74         if (!(bh = sysv_file_bread(inode, 0, 0))) { /* is reading 1 block enough ?? */
  75                 iput(inode);
  76                 iput(dir);
  77                 return -EIO;
  78         }
  79         iput(inode);
  80         current->link_count++;
  81         error = open_namei(bh->b_data,flag,mode,res_inode,dir);
  82         current->link_count--;
  83         brelse(bh);
  84         return error;
  85 }
  86 
  87 static int sysv_readlink(struct inode * inode, char * buffer, int buflen)
     /*  */
  88 {
  89         struct buffer_head * bh;
  90         char * bh_data;
  91         int i;
  92         char c;
  93 
  94         if (!S_ISLNK(inode->i_mode)) {
  95                 iput(inode);
  96                 return -EINVAL;
  97         }
  98         if (buflen > inode->i_sb->sv_block_size_1)
  99                 buflen = inode->i_sb->sv_block_size_1;
 100         bh = sysv_file_bread(inode, 0, 0);
 101         iput(inode);
 102         if (!bh)
 103                 return 0;
 104         bh_data = bh->b_data;
 105         i = 0;
 106         while (i<buflen && (c = bh_data[i])) {
 107                 i++;
 108                 put_user(c,buffer++);
 109         }
 110         brelse(bh);
 111         return i;
 112 }
/* */
root/fs/sysv/symlink.c

DEFINITIONS
