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/*
* linux/fs/nfs/callback.c
*
* Copyright (C) 2004 Trond Myklebust
*
* NFSv4 callback handling
*/
#include <linux/completion.h>
#include <linux/ip.h>
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/nfs_fs.h>
#include <linux/mutex.h>
#include <linux/freezer.h>
#include <net/inet_sock.h>
#include "nfs4_fs.h"
#include "callback.h"
#include "internal.h"
#define NFSDBG_FACILITY NFSDBG_CALLBACK
struct nfs_callback_data {
unsigned int users;
struct svc_serv *serv;
pid_t pid;
struct completion started;
struct completion stopped;
};
static struct nfs_callback_data nfs_callback_info;
static DEFINE_MUTEX(nfs_callback_mutex);
static struct svc_program nfs4_callback_program;
unsigned int nfs_callback_set_tcpport;
unsigned short nfs_callback_tcpport;
static const int nfs_set_port_min = 0;
static const int nfs_set_port_max = 65535;
static int param_set_port(const char *val, struct kernel_param *kp)
{
char *endp;
int num = simple_strtol(val, &endp, 0);
if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
return -EINVAL;
*((int *)kp->arg) = num;
return 0;
}
module_param_call(callback_tcpport, param_set_port, param_get_int,
&nfs_callback_set_tcpport, 0644);
/*
* This is the callback kernel thread.
*/
static void nfs_callback_svc(struct svc_rqst *rqstp)
{
int err;
__module_get(THIS_MODULE);
lock_kernel();
nfs_callback_info.pid = current->pid;
daemonize("nfsv4-svc");
/* Process request with signals blocked, but allow SIGKILL. */
allow_signal(SIGKILL);
set_freezable();
complete(&nfs_callback_info.started);
for(;;) {
if (signalled()) {
if (nfs_callback_info.users == 0)
break;
flush_signals(current);
}
/*
* Listen for a request on the socket
*/
err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
if (err == -EAGAIN || err == -EINTR)
continue;
if (err < 0) {
printk(KERN_WARNING
"%s: terminating on error %d\n",
__FUNCTION__, -err);
break;
}
svc_process(rqstp);
}
svc_exit_thread(rqstp);
nfs_callback_info.pid = 0;
complete(&nfs_callback_info.stopped);
unlock_kernel();
module_put_and_exit(0);
}
/*
* Bring up the server process if it is not already up.
*/
int nfs_callback_up(void)
{
struct svc_serv *serv = NULL;
int ret = 0;
lock_kernel();
mutex_lock(&nfs_callback_mutex);
if (nfs_callback_info.users++ || nfs_callback_info.pid != 0)
goto out;
init_completion(&nfs_callback_info.started);
init_completion(&nfs_callback_info.stopped);
serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
ret = -ENOMEM;
if (!serv)
goto out_err;
ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport,
SVC_SOCK_ANONYMOUS);
if (ret <= 0)
goto out_err;
nfs_callback_tcpport = ret;
dprintk("Callback port = 0x%x\n", nfs_callback_tcpport);
ret = svc_create_thread(nfs_callback_svc, serv);
if (ret < 0)
goto out_err;
nfs_callback_info.serv = serv;
wait_for_completion(&nfs_callback_info.started);
out:
/*
* svc_create creates the svc_serv with sv_nrthreads == 1, and then
* svc_create_thread increments that. So we need to call svc_destroy
* on both success and failure so that the refcount is 1 when the
* thread exits.
*/
if (serv)
svc_destroy(serv);
mutex_unlock(&nfs_callback_mutex);
unlock_kernel();
return ret;
out_err:
dprintk("Couldn't create callback socket or server thread; err = %d\n",
ret);
nfs_callback_info.users--;
goto out;
}
/*
* Kill the server process if it is not already up.
*/
void nfs_callback_down(void)
{
lock_kernel();
mutex_lock(&nfs_callback_mutex);
nfs_callback_info.users--;
do {
if (nfs_callback_info.users != 0 || nfs_callback_info.pid == 0)
break;
if (kill_proc(nfs_callback_info.pid, SIGKILL, 1) < 0)
break;
} while (wait_for_completion_timeout(&nfs_callback_info.stopped, 5*HZ) == 0);
mutex_unlock(&nfs_callback_mutex);
unlock_kernel();
}
static int nfs_callback_authenticate(struct svc_rqst *rqstp)
{
struct nfs_client *clp;
char buf[RPC_MAX_ADDRBUFLEN];
/* Don't talk to strangers */
clp = nfs_find_client(svc_addr(rqstp), 4);
if (clp == NULL)
return SVC_DROP;
dprintk("%s: %s NFSv4 callback!\n", __FUNCTION__,
svc_print_addr(rqstp, buf, sizeof(buf)));
nfs_put_client(clp);
switch (rqstp->rq_authop->flavour) {
case RPC_AUTH_NULL:
if (rqstp->rq_proc != CB_NULL)
return SVC_DENIED;
break;
case RPC_AUTH_UNIX:
break;
case RPC_AUTH_GSS:
/* FIXME: RPCSEC_GSS handling? */
default:
return SVC_DENIED;
}
return SVC_OK;
}
/*
* Define NFS4 callback program
*/
static struct svc_version *nfs4_callback_version[] = {
[1] = &nfs4_callback_version1,
};
static struct svc_stat nfs4_callback_stats;
static struct svc_program nfs4_callback_program = {
.pg_prog = NFS4_CALLBACK, /* RPC service number */
.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
.pg_vers = nfs4_callback_version, /* version table */
.pg_name = "NFSv4 callback", /* service name */
.pg_class = "nfs", /* authentication class */
.pg_stats = &nfs4_callback_stats,
.pg_authenticate = nfs_callback_authenticate,
};
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