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 Latchesar Ionkov <lucho@ionkov.net>
   7  *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2 of the License, or
  12  *  (at your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to:
  21  *  Free Software Foundation
  22  *  51 Franklin Street, Fifth Floor
  23  *  Boston, MA  02111-1301  USA
  24  *
  25  */
  26
  27 #include <linux/config.h>
  28 #include <linux/module.h>
  29 #include <linux/net.h>
  30 #include <linux/ipv6.h>
  31 #include <linux/errno.h>
  32 #include <linux/kernel.h>
  33 #include <linux/un.h>
  34 #include <asm/uaccess.h>
  35 #include <linux/inet.h>
  36 #include <linux/idr.h>
  37 #include <linux/file.h>
  38
  39 #include "debug.h"
  40 #include "v9fs.h"
  41 #include "transport.h"
  42
  43 struct v9fs_trans_fd {
  44         struct file *in_file;
  45         struct file *out_file;
  46 };
  47
  48 /**
  49  * v9fs_fd_recv - receive from a socket
  50  * @v9ses: session information
  51  * @v: buffer to receive data into
  52  * @len: size of receive buffer
  53  *
  54  */
  55
  56 static int v9fs_fd_recv(struct v9fs_transport *trans, void *v, int len)
  57 {
  58         struct v9fs_trans_fd *ts = trans ? trans->priv : NULL;
  59
  60         if (!trans || trans->status != Connected || !ts)
  61                 return -EIO;
  62
  63         return kernel_read(ts->in_file, ts->in_file->f_pos, v, len);
  64 }
  65
  66 /**
  67  * v9fs_fd_send - send to a socket
  68  * @v9ses: session information
  69  * @v: buffer to send data from
  70  * @len: size of send buffer
  71  *
  72  */
  73
  74 static int v9fs_fd_send(struct v9fs_transport *trans, void *v, int len)
  75 {
  76         struct v9fs_trans_fd *ts = trans ? trans->priv : NULL;
  77         mm_segment_t oldfs = get_fs();
  78         int ret = 0;
  79
  80         if (!trans || trans->status != Connected || !ts)
  81                 return -EIO;
  82
  83         set_fs(get_ds());
  84         /* The cast to a user pointer is valid due to the set_fs() */
  85         ret = vfs_write(ts->out_file, (void __user *)v, len, &ts->out_file->f_pos);
  86         set_fs(oldfs);
  87
  88         return ret;
  89 }
  90
  91 /**
  92  * v9fs_fd_init - initialize file descriptor transport
  93  * @v9ses: session information
  94  * @addr: address of server to mount
  95  * @data: mount options
  96  *
  97  */
  98
  99 static int
 100 v9fs_fd_init(struct v9fs_session_info *v9ses, const char *addr, char *data)
 101 {
 102         struct v9fs_trans_fd *ts = NULL;
 103         struct v9fs_transport *trans = v9ses->transport;
 104
 105         if((v9ses->wfdno == ~0) || (v9ses->rfdno == ~0)) {
 106                 printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
 107                 return -ENOPROTOOPT;
 108         }
 109
 110         ts = kmalloc(sizeof(struct v9fs_trans_fd), GFP_KERNEL);
 111
 112         if (!ts)
 113                 return -ENOMEM;
 114
 115         ts->in_file = fget( v9ses->rfdno );
 116         ts->out_file = fget( v9ses->wfdno );
 117
 118         if (!ts->in_file || !ts->out_file) {
 119                 if (ts->in_file)
 120                         fput(ts->in_file);
 121
 122                 if (ts->out_file)
 123                         fput(ts->out_file);
 124
 125                 kfree(ts);
 126                 return -EIO;
 127         }
 128
 129         trans->priv = ts;
 130         trans->status = Connected;
 131
 132         return 0;
 133 }
 134
 135
 136 /**
 137  * v9fs_fd_close - shutdown file descriptor
 138  * @trans: private socket structure
 139  *
 140  */
 141
 142 static void v9fs_fd_close(struct v9fs_transport *trans)
 143 {
 144         struct v9fs_trans_fd *ts;
 145
 146         if (!trans)
 147                 return;
 148
 149         ts = xchg(&trans->priv, NULL);
 150
 151         if (!ts)
 152                 return;
 153
 154         trans->status = Disconnected;
 155         if (ts->in_file)
 156                 fput(ts->in_file);
 157
 158         if (ts->out_file)
 159                 fput(ts->out_file);
 160
 161         kfree(ts);
 162 }
 163
 164 static unsigned int
 165 v9fs_fd_poll(struct v9fs_transport *trans, struct poll_table_struct *pt)
 166 {
 167         int ret, n;
 168         struct v9fs_trans_fd *ts;
 169         mm_segment_t oldfs;
 170
 171         if (!trans)
 172                 return -EIO;
 173
 174         ts = trans->priv;
 175         if (trans->status != Connected || !ts)
 176                 return -EIO;
 177
 178         oldfs = get_fs();
 179         set_fs(get_ds());
 180
 181         if (!ts->in_file->f_op || !ts->in_file->f_op->poll) {
 182                 ret = -EIO;
 183                 goto end;
 184         }
 185
 186         ret = ts->in_file->f_op->poll(ts->in_file, pt);
 187
 188         if (ts->out_file != ts->in_file) {
 189                 if (!ts->out_file->f_op || !ts->out_file->f_op->poll) {
 190                         ret = -EIO;
 191                         goto end;
 192                 }
 193
 194                 n = ts->out_file->f_op->poll(ts->out_file, pt);
 195
 196                 ret &= ~POLLOUT;
 197                 n &= ~POLLIN;
 198
 199                 ret |= n;
 200         }
 201
 202 end:
 203         set_fs(oldfs);
 204         return ret;
 205 }
 206
 207
 208 struct v9fs_transport v9fs_trans_fd = {
 209         .init = v9fs_fd_init,
 210         .write = v9fs_fd_send,
 211         .read = v9fs_fd_recv,
 212         .close = v9fs_fd_close,
 213         .poll = v9fs_fd_poll,
 214 };
 215