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         oldfs = get_fs();
  84         set_fs(get_ds());
  85         /* The cast to a user pointer is valid due to the set_fs() */
  86         ret = vfs_write(ts->out_file, (void __user *)v, len, &ts->out_file->f_pos);
  87         set_fs(oldfs);
  88
  89         return ret;
  90 }
  91
  92 /**
  93  * v9fs_fd_init - initialize file descriptor transport
  94  * @v9ses: session information
  95  * @addr: address of server to mount
  96  * @data: mount options
  97  *
  98  */
  99
 100 static int
 101 v9fs_fd_init(struct v9fs_session_info *v9ses, const char *addr, char *data)
 102 {
 103         struct v9fs_trans_fd *ts = NULL;
 104         struct v9fs_transport *trans = v9ses->transport;
 105
 106         if((v9ses->wfdno == ~0) || (v9ses->rfdno == ~0)) {
 107                 printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
 108                 return -ENOPROTOOPT;
 109         }
 110
 111         ts = kmalloc(sizeof(struct v9fs_trans_fd), GFP_KERNEL);
 112
 113         if (!ts)
 114                 return -ENOMEM;
 115
 116         ts->in_file = fget( v9ses->rfdno );
 117         ts->out_file = fget( v9ses->wfdno );
 118
 119         if (!ts->in_file || !ts->out_file) {
 120                 if (ts->in_file)
 121                         fput(ts->in_file);
 122
 123                 if (ts->out_file)
 124                         fput(ts->out_file);
 125
 126                 kfree(ts);
 127                 return -EIO;
 128         }
 129
 130         trans->priv = ts;
 131         trans->status = Connected;
 132
 133         return 0;
 134 }
 135
 136
 137 /**
 138  * v9fs_fd_close - shutdown file descriptor
 139  * @trans: private socket structure
 140  *
 141  */
 142
 143 static void v9fs_fd_close(struct v9fs_transport *trans)
 144 {
 145         struct v9fs_trans_fd *ts;
 146
 147         if (!trans)
 148                 return;
 149
 150         ts = xchg(&trans->priv, NULL);
 151
 152         if (!ts)
 153                 return;
 154
 155         trans->status = Disconnected;
 156         if (ts->in_file)
 157                 fput(ts->in_file);
 158
 159         if (ts->out_file)
 160                 fput(ts->out_file);
 161
 162         kfree(ts);
 163 }
 164
 165 static unsigned int
 166 v9fs_fd_poll(struct v9fs_transport *trans, struct poll_table_struct *pt)
 167 {
 168         int ret, n;
 169         struct v9fs_trans_fd *ts;
 170         mm_segment_t oldfs;
 171
 172         if (!trans)
 173                 return -EIO;
 174
 175         ts = trans->priv;
 176         if (trans->status != Connected || !ts)
 177                 return -EIO;
 178
 179         oldfs = get_fs();
 180         set_fs(get_ds());
 181
 182         if (!ts->in_file->f_op || !ts->in_file->f_op->poll) {
 183                 ret = -EIO;
 184                 goto end;
 185         }
 186
 187         ret = ts->in_file->f_op->poll(ts->in_file, pt);
 188
 189         if (ts->out_file != ts->in_file) {
 190                 if (!ts->out_file->f_op || !ts->out_file->f_op->poll) {
 191                         ret = -EIO;
 192                         goto end;
 193                 }
 194
 195                 n = ts->out_file->f_op->poll(ts->out_file, pt);
 196
 197                 ret &= ~POLLOUT;
 198                 n &= ~POLLIN;
 199
 200                 ret |= n;
 201         }
 202
 203 end:
 204         set_fs(oldfs);
 205         return ret;
 206 }
 207
 208
 209 struct v9fs_transport v9fs_trans_fd = {
 210         .init = v9fs_fd_init,
 211         .write = v9fs_fd_send,
 212         .read = v9fs_fd_recv,
 213         .close = v9fs_fd_close,
 214         .poll = v9fs_fd_poll,
 215 };
 216