fs/9p/trans_fd.c

   1 /*
   2  * linux/fs/9p/trans_fd.c
   3  *
   4  * File Descriptor Transport Layer
   5  *
   6  *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #include <linux/config.h>
  27 #include <linux/module.h>
  28 #include <linux/net.h>
  29 #include <linux/ipv6.h>
  30 #include <linux/errno.h>
  31 #include <linux/kernel.h>
  32 #include <linux/un.h>
  33 #include <asm/uaccess.h>
  34 #include <linux/inet.h>
  35 #include <linux/idr.h>
  36 #include <linux/file.h>
  37
  38 #include "debug.h"
  39 #include "v9fs.h"
  40 #include "transport.h"
  41
  42 struct v9fs_trans_fd {
  43         struct file *in_file;
  44         struct file *out_file;
  45 };
  46
  47 /**
  48  * v9fs_fd_recv - receive from a socket
  49  * @v9ses: session information
  50  * @v: buffer to receive data into
  51  * @len: size of receive buffer
  52  *
  53  */
  54
  55 static int v9fs_fd_recv(struct v9fs_transport *trans, void *v, int len)
  56 {
  57         struct v9fs_trans_fd *ts = trans ? trans->priv : NULL;
  58
  59         if (!trans || trans->status != Connected || !ts)
  60                 return -EIO;
  61
  62         return kernel_read(ts->in_file, ts->in_file->f_pos, v, len);
  63 }
  64
  65 /**
  66  * v9fs_fd_send - send to a socket
  67  * @v9ses: session information
  68  * @v: buffer to send data from
  69  * @len: size of send buffer
  70  *
  71  */
  72
  73 static int v9fs_fd_send(struct v9fs_transport *trans, void *v, int len)
  74 {
  75         struct v9fs_trans_fd *ts = trans ? trans->priv : NULL;
  76         mm_segment_t oldfs = get_fs();
  77         int ret = 0;
  78
  79         if (!trans || trans->status != Connected || !ts)
  80                 return -EIO;
  81
  82         set_fs(get_ds());
  83         /* The cast to a user pointer is valid due to the set_fs() */
  84         ret = vfs_write(ts->out_file, (void __user *)v, len, &ts->out_file->f_pos);
  85         set_fs(oldfs);
  86
  87         return ret;
  88 }
  89
  90 /**
  91  * v9fs_fd_init - initialize file descriptor transport
  92  * @v9ses: session information
  93  * @addr: address of server to mount
  94  * @data: mount options
  95  *
  96  */
  97
  98 static int
  99 v9fs_fd_init(struct v9fs_session_info *v9ses, const char *addr, char *data)
 100 {
 101         struct v9fs_trans_fd *ts = NULL;
 102         struct v9fs_transport *trans = v9ses->transport;
 103
 104         if((v9ses->wfdno == ~0) || (v9ses->rfdno == ~0)) {
 105                 printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
 106                 return -ENOPROTOOPT;
 107         }
 108
 109         sema_init(&trans->writelock, 1);
 110         sema_init(&trans->readlock, 1);
 111
 112         ts = kmalloc(sizeof(struct v9fs_trans_fd), GFP_KERNEL);
 113
 114         if (!ts)
 115                 return -ENOMEM;
 116
 117         ts->in_file = fget( v9ses->rfdno );
 118         ts->out_file = fget( v9ses->wfdno );
 119
 120         if (!ts->in_file || !ts->out_file) {
 121                 if (ts->in_file)
 122                         fput(ts->in_file);
 123
 124                 if (ts->out_file)
 125                         fput(ts->out_file);
 126
 127                 kfree(ts);
 128                 return -EIO;
 129         }
 130
 131         trans->priv = ts;
 132         trans->status = Connected;
 133
 134         return 0;
 135 }
 136
 137
 138 /**
 139  * v9fs_fd_close - shutdown file descriptor
 140  * @trans: private socket structure
 141  *
 142  */
 143
 144 static void v9fs_fd_close(struct v9fs_transport *trans)
 145 {
 146         struct v9fs_trans_fd *ts;
 147
 148         if (!trans)
 149                 return;
 150
 151         trans->status = Disconnected;
 152         ts = trans->priv;
 153
 154         if (!ts)
 155                 return;
 156
 157         if (ts->in_file)
 158                 fput(ts->in_file);
 159
 160         if (ts->out_file)
 161                 fput(ts->out_file);
 162
 163         kfree(ts);
 164 }
 165
 166 struct v9fs_transport v9fs_trans_fd = {
 167         .init = v9fs_fd_init,
 168         .write = v9fs_fd_send,
 169         .read = v9fs_fd_recv,
 170         .close = v9fs_fd_close,
 171 };
 172