441 lines
9.7 KiB
C
441 lines
9.7 KiB
C
![]() |
/*
|
||
|
* linux/fs/9p/mux.c
|
||
|
*
|
||
|
* Protocol Multiplexer
|
||
|
*
|
||
|
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
|
||
|
* Copyright (C) 2004 by Latchesar Ionkov <lucho@ionkov.net>
|
||
|
*
|
||
|
* This program is free software; you can redistribute it and/or modify
|
||
|
* it under the terms of the GNU General Public License as published by
|
||
|
* the Free Software Foundation; either version 2 of the License, or
|
||
|
* (at your option) any later version.
|
||
|
*
|
||
|
* This program is distributed in the hope that it will be useful,
|
||
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
* GNU General Public License for more details.
|
||
|
*
|
||
|
* You should have received a copy of the GNU General Public License
|
||
|
* along with this program; if not, write to:
|
||
|
* Free Software Foundation
|
||
|
* 51 Franklin Street, Fifth Floor
|
||
|
* Boston, MA 02111-1301 USA
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
#include <linux/config.h>
|
||
|
#include <linux/module.h>
|
||
|
#include <linux/errno.h>
|
||
|
#include <linux/fs.h>
|
||
|
#include <linux/kthread.h>
|
||
|
#include <linux/idr.h>
|
||
|
|
||
|
#include "debug.h"
|
||
|
#include "v9fs.h"
|
||
|
#include "9p.h"
|
||
|
#include "transport.h"
|
||
|
#include "conv.h"
|
||
|
#include "mux.h"
|
||
|
|
||
|
/**
|
||
|
* dprintcond - print condition of session info
|
||
|
* @v9ses: session info structure
|
||
|
* @req: RPC request structure
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
static inline int
|
||
|
dprintcond(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
|
||
|
{
|
||
|
dprintk(DEBUG_MUX, "condition: %d, %p\n", v9ses->transport->status,
|
||
|
req->rcall);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* xread - force read of a certain number of bytes
|
||
|
* @v9ses: session info structure
|
||
|
* @ptr: pointer to buffer
|
||
|
* @sz: number of bytes to read
|
||
|
*
|
||
|
* Chuck Cranor CS-533 project1
|
||
|
*/
|
||
|
|
||
|
static int xread(struct v9fs_session_info *v9ses, void *ptr, unsigned long sz)
|
||
|
{
|
||
|
int rd = 0;
|
||
|
int ret = 0;
|
||
|
while (rd < sz) {
|
||
|
ret = v9ses->transport->read(v9ses->transport, ptr, sz - rd);
|
||
|
if (ret <= 0) {
|
||
|
dprintk(DEBUG_ERROR, "xread errno %d\n", ret);
|
||
|
return ret;
|
||
|
}
|
||
|
rd += ret;
|
||
|
ptr += ret;
|
||
|
}
|
||
|
return (rd);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* read_message - read a full 9P2000 fcall packet
|
||
|
* @v9ses: session info structure
|
||
|
* @rcall: fcall structure to read into
|
||
|
* @rcalllen: size of fcall buffer
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
static int
|
||
|
read_message(struct v9fs_session_info *v9ses,
|
||
|
struct v9fs_fcall *rcall, int rcalllen)
|
||
|
{
|
||
|
unsigned char buf[4];
|
||
|
void *data;
|
||
|
int size = 0;
|
||
|
int res = 0;
|
||
|
|
||
|
res = xread(v9ses, buf, sizeof(buf));
|
||
|
if (res < 0) {
|
||
|
dprintk(DEBUG_ERROR,
|
||
|
"Reading of count field failed returned: %d\n", res);
|
||
|
return res;
|
||
|
}
|
||
|
|
||
|
if (res < 4) {
|
||
|
dprintk(DEBUG_ERROR,
|
||
|
"Reading of count field failed returned: %d\n", res);
|
||
|
return -EIO;
|
||
|
}
|
||
|
|
||
|
size = buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
|
||
|
dprintk(DEBUG_MUX, "got a packet count: %d\n", size);
|
||
|
|
||
|
/* adjust for the four bytes of size */
|
||
|
size -= 4;
|
||
|
|
||
|
if (size > v9ses->maxdata) {
|
||
|
dprintk(DEBUG_ERROR, "packet too big: %d\n", size);
|
||
|
return -E2BIG;
|
||
|
}
|
||
|
|
||
|
data = kmalloc(size, GFP_KERNEL);
|
||
|
if (!data) {
|
||
|
eprintk(KERN_WARNING, "out of memory\n");
|
||
|
return -ENOMEM;
|
||
|
}
|
||
|
|
||
|
res = xread(v9ses, data, size);
|
||
|
if (res < size) {
|
||
|
dprintk(DEBUG_ERROR, "Reading of fcall failed returned: %d\n",
|
||
|
res);
|
||
|
kfree(data);
|
||
|
return res;
|
||
|
}
|
||
|
|
||
|
/* we now have an in-memory string that is the reply.
|
||
|
* deserialize it. There is very little to go wrong at this point
|
||
|
* save for v9fs_alloc errors.
|
||
|
*/
|
||
|
res = v9fs_deserialize_fcall(v9ses, size, data, v9ses->maxdata,
|
||
|
rcall, rcalllen);
|
||
|
|
||
|
kfree(data);
|
||
|
|
||
|
if (res < 0)
|
||
|
return res;
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* v9fs_recv - receive an RPC response for a particular tag
|
||
|
* @v9ses: session info structure
|
||
|
* @req: RPC request structure
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
static int v9fs_recv(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
|
||
|
{
|
||
|
int ret = 0;
|
||
|
|
||
|
dprintk(DEBUG_MUX, "waiting for response: %d\n", req->tcall->tag);
|
||
|
ret = wait_event_interruptible(v9ses->read_wait,
|
||
|
((v9ses->transport->status != Connected) ||
|
||
|
(req->rcall != 0) || dprintcond(v9ses, req)));
|
||
|
|
||
|
dprintk(DEBUG_MUX, "got it: rcall %p\n", req->rcall);
|
||
|
if (v9ses->transport->status == Disconnected)
|
||
|
return -ECONNRESET;
|
||
|
|
||
|
if (ret == 0) {
|
||
|
spin_lock(&v9ses->muxlock);
|
||
|
list_del(&req->next);
|
||
|
spin_unlock(&v9ses->muxlock);
|
||
|
}
|
||
|
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* v9fs_send - send a 9P request
|
||
|
* @v9ses: session info structure
|
||
|
* @req: RPC request to send
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
static int v9fs_send(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
|
||
|
{
|
||
|
int ret = -1;
|
||
|
void *data = NULL;
|
||
|
struct v9fs_fcall *tcall = req->tcall;
|
||
|
|
||
|
data = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
|
||
|
if (!data)
|
||
|
return -ENOMEM;
|
||
|
|
||
|
tcall->size = 0; /* enforce size recalculation */
|
||
|
ret =
|
||
|
v9fs_serialize_fcall(v9ses, tcall, data,
|
||
|
v9ses->maxdata + V9FS_IOHDRSZ);
|
||
|
if (ret < 0)
|
||
|
goto free_data;
|
||
|
|
||
|
spin_lock(&v9ses->muxlock);
|
||
|
list_add(&req->next, &v9ses->mux_fcalls);
|
||
|
spin_unlock(&v9ses->muxlock);
|
||
|
|
||
|
dprintk(DEBUG_MUX, "sending message: tag %d size %d\n", tcall->tag,
|
||
|
tcall->size);
|
||
|
ret = v9ses->transport->write(v9ses->transport, data, tcall->size);
|
||
|
|
||
|
if (ret != tcall->size) {
|
||
|
spin_lock(&v9ses->muxlock);
|
||
|
list_del(&req->next);
|
||
|
kfree(req->rcall);
|
||
|
|
||
|
spin_unlock(&v9ses->muxlock);
|
||
|
if (ret >= 0)
|
||
|
ret = -EREMOTEIO;
|
||
|
} else
|
||
|
ret = 0;
|
||
|
|
||
|
free_data:
|
||
|
kfree(data);
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* v9fs_mux_rpc - send a request, receive a response
|
||
|
* @v9ses: session info structure
|
||
|
* @tcall: fcall to send
|
||
|
* @rcall: buffer to place response into
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
long
|
||
|
v9fs_mux_rpc(struct v9fs_session_info *v9ses, struct v9fs_fcall *tcall,
|
||
|
struct v9fs_fcall **rcall)
|
||
|
{
|
||
|
int tid = -1;
|
||
|
struct v9fs_fcall *fcall = NULL;
|
||
|
struct v9fs_rpcreq req;
|
||
|
int ret = -1;
|
||
|
|
||
|
if (!v9ses)
|
||
|
return -EINVAL;
|
||
|
|
||
|
if (rcall)
|
||
|
*rcall = NULL;
|
||
|
|
||
|
if (tcall->id != TVERSION) {
|
||
|
tid = v9fs_get_idpool(&v9ses->tidpool);
|
||
|
if (tid < 0)
|
||
|
return -ENOMEM;
|
||
|
}
|
||
|
|
||
|
tcall->tag = tid;
|
||
|
|
||
|
req.tcall = tcall;
|
||
|
req.rcall = NULL;
|
||
|
|
||
|
ret = v9fs_send(v9ses, &req);
|
||
|
|
||
|
if (ret < 0) {
|
||
|
if (tcall->id != TVERSION)
|
||
|
v9fs_put_idpool(tid, &v9ses->tidpool);
|
||
|
dprintk(DEBUG_MUX, "error %d\n", ret);
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
ret = v9fs_recv(v9ses, &req);
|
||
|
|
||
|
fcall = req.rcall;
|
||
|
|
||
|
dprintk(DEBUG_MUX, "received: tag=%x, ret=%d\n", tcall->tag, ret);
|
||
|
if (ret == -ERESTARTSYS) {
|
||
|
if (v9ses->transport->status != Disconnected
|
||
|
&& tcall->id != TFLUSH) {
|
||
|
unsigned long flags;
|
||
|
|
||
|
dprintk(DEBUG_MUX, "flushing the tag: %d\n",
|
||
|
tcall->tag);
|
||
|
clear_thread_flag(TIF_SIGPENDING);
|
||
|
v9fs_t_flush(v9ses, tcall->tag);
|
||
|
spin_lock_irqsave(¤t->sighand->siglock, flags);
|
||
|
recalc_sigpending();
|
||
|
spin_unlock_irqrestore(¤t->sighand->siglock,
|
||
|
flags);
|
||
|
dprintk(DEBUG_MUX, "flushing done\n");
|
||
|
}
|
||
|
|
||
|
goto release_req;
|
||
|
} else if (ret < 0)
|
||
|
goto release_req;
|
||
|
|
||
|
if (!fcall)
|
||
|
ret = -EIO;
|
||
|
else {
|
||
|
if (fcall->id == RERROR) {
|
||
|
ret = v9fs_errstr2errno(fcall->params.rerror.error);
|
||
|
if (ret == 0) { /* string match failed */
|
||
|
if (fcall->params.rerror.errno)
|
||
|
ret = -(fcall->params.rerror.errno);
|
||
|
else
|
||
|
ret = -ESERVERFAULT;
|
||
|
}
|
||
|
} else if (fcall->id != tcall->id + 1) {
|
||
|
dprintk(DEBUG_ERROR,
|
||
|
"fcall mismatch: expected %d, got %d\n",
|
||
|
tcall->id + 1, fcall->id);
|
||
|
ret = -EIO;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
release_req:
|
||
|
if (tcall->id != TVERSION)
|
||
|
v9fs_put_idpool(tid, &v9ses->tidpool);
|
||
|
if (rcall)
|
||
|
*rcall = fcall;
|
||
|
else
|
||
|
kfree(fcall);
|
||
|
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* v9fs_recvproc - kproc to handle demultiplexing responses
|
||
|
* @data: session info structure
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
static int v9fs_recvproc(void *data)
|
||
|
{
|
||
|
struct v9fs_session_info *v9ses = (struct v9fs_session_info *)data;
|
||
|
struct v9fs_fcall *rcall = NULL;
|
||
|
struct v9fs_rpcreq *rptr;
|
||
|
struct v9fs_rpcreq *req;
|
||
|
struct v9fs_rpcreq *rreq;
|
||
|
int err = 0;
|
||
|
|
||
|
allow_signal(SIGKILL);
|
||
|
set_current_state(TASK_INTERRUPTIBLE);
|
||
|
complete(&v9ses->proccmpl);
|
||
|
while (!kthread_should_stop() && err >= 0) {
|
||
|
req = rptr = rreq = NULL;
|
||
|
|
||
|
rcall = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
|
||
|
if (!rcall) {
|
||
|
eprintk(KERN_ERR, "no memory for buffers\n");
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
err = read_message(v9ses, rcall, v9ses->maxdata + V9FS_IOHDRSZ);
|
||
|
if (err < 0) {
|
||
|
kfree(rcall);
|
||
|
break;
|
||
|
}
|
||
|
spin_lock(&v9ses->muxlock);
|
||
|
list_for_each_entry_safe(rreq, rptr, &v9ses->mux_fcalls, next) {
|
||
|
if (rreq->tcall->tag == rcall->tag) {
|
||
|
req = rreq;
|
||
|
req->rcall = rcall;
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if (req && (req->tcall->id == TFLUSH)) {
|
||
|
struct v9fs_rpcreq *treq = NULL;
|
||
|
list_for_each_entry_safe(treq, rptr, &v9ses->mux_fcalls, next) {
|
||
|
if (treq->tcall->tag ==
|
||
|
req->tcall->params.tflush.oldtag) {
|
||
|
list_del(&rptr->next);
|
||
|
kfree(treq->rcall);
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
spin_unlock(&v9ses->muxlock);
|
||
|
|
||
|
if (!req) {
|
||
|
dprintk(DEBUG_ERROR,
|
||
|
"unexpected response: id %d tag %d\n",
|
||
|
rcall->id, rcall->tag);
|
||
|
|
||
|
kfree(rcall);
|
||
|
}
|
||
|
|
||
|
wake_up_all(&v9ses->read_wait);
|
||
|
set_current_state(TASK_INTERRUPTIBLE);
|
||
|
}
|
||
|
|
||
|
/* Inform all pending processes about the failure */
|
||
|
wake_up_all(&v9ses->read_wait);
|
||
|
|
||
|
if (signal_pending(current))
|
||
|
complete(&v9ses->proccmpl);
|
||
|
|
||
|
dprintk(DEBUG_MUX, "recvproc: end\n");
|
||
|
v9ses->recvproc = NULL;
|
||
|
|
||
|
return err >= 0;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* v9fs_mux_init - initialize multiplexer (spawn kproc)
|
||
|
* @v9ses: session info structure
|
||
|
* @dev_name: mount device information (to create unique kproc)
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
int v9fs_mux_init(struct v9fs_session_info *v9ses, const char *dev_name)
|
||
|
{
|
||
|
char procname[60];
|
||
|
|
||
|
strncpy(procname, dev_name, sizeof(procname));
|
||
|
procname[sizeof(procname) - 1] = 0;
|
||
|
|
||
|
init_waitqueue_head(&v9ses->read_wait);
|
||
|
init_completion(&v9ses->fcread);
|
||
|
init_completion(&v9ses->proccmpl);
|
||
|
spin_lock_init(&v9ses->muxlock);
|
||
|
INIT_LIST_HEAD(&v9ses->mux_fcalls);
|
||
|
v9ses->recvproc = NULL;
|
||
|
v9ses->curfcall = NULL;
|
||
|
|
||
|
v9ses->recvproc = kthread_create(v9fs_recvproc, v9ses,
|
||
|
"v9fs_recvproc %s", procname);
|
||
|
|
||
|
if (IS_ERR(v9ses->recvproc)) {
|
||
|
eprintk(KERN_ERR, "cannot create receiving thread\n");
|
||
|
v9fs_session_close(v9ses);
|
||
|
return -ECONNABORTED;
|
||
|
}
|
||
|
|
||
|
wake_up_process(v9ses->recvproc);
|
||
|
wait_for_completion(&v9ses->proccmpl);
|
||
|
|
||
|
return 0;
|
||
|
}
|