1 /* 2 * linux/fs/nfs/callback.c 3 * 4 * Copyright (C) 2004 Trond Myklebust 5 * 6 * NFSv4 callback handling 7 */ 8 9 #include <linux/completion.h> 10 #include <linux/ip.h> 11 #include <linux/module.h> 12 #include <linux/smp_lock.h> 13 #include <linux/sunrpc/svc.h> 14 #include <linux/sunrpc/svcsock.h> 15 #include <linux/nfs_fs.h> 16 #include <linux/mutex.h> 17 #include <linux/freezer.h> 18 19 #include <net/inet_sock.h> 20 21 #include "nfs4_fs.h" 22 #include "callback.h" 23 #include "internal.h" 24 25 #define NFSDBG_FACILITY NFSDBG_CALLBACK 26 27 struct nfs_callback_data { 28 unsigned int users; 29 struct svc_serv *serv; 30 pid_t pid; 31 struct completion started; 32 struct completion stopped; 33 }; 34 35 static struct nfs_callback_data nfs_callback_info; 36 static DEFINE_MUTEX(nfs_callback_mutex); 37 static struct svc_program nfs4_callback_program; 38 39 unsigned int nfs_callback_set_tcpport; 40 unsigned short nfs_callback_tcpport; 41 static const int nfs_set_port_min = 0; 42 static const int nfs_set_port_max = 65535; 43 44 static int param_set_port(const char *val, struct kernel_param *kp) 45 { 46 char *endp; 47 int num = simple_strtol(val, &endp, 0); 48 if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max) 49 return -EINVAL; 50 *((int *)kp->arg) = num; 51 return 0; 52 } 53 54 module_param_call(callback_tcpport, param_set_port, param_get_int, 55 &nfs_callback_set_tcpport, 0644); 56 57 /* 58 * This is the callback kernel thread. 59 */ 60 static void nfs_callback_svc(struct svc_rqst *rqstp) 61 { 62 int err; 63 64 __module_get(THIS_MODULE); 65 lock_kernel(); 66 67 nfs_callback_info.pid = current->pid; 68 daemonize("nfsv4-svc"); 69 /* Process request with signals blocked, but allow SIGKILL. */ 70 allow_signal(SIGKILL); 71 set_freezable(); 72 73 complete(&nfs_callback_info.started); 74 75 for(;;) { 76 if (signalled()) { 77 if (nfs_callback_info.users == 0) 78 break; 79 flush_signals(current); 80 } 81 /* 82 * Listen for a request on the socket 83 */ 84 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT); 85 if (err == -EAGAIN || err == -EINTR) 86 continue; 87 if (err < 0) { 88 printk(KERN_WARNING 89 "%s: terminating on error %d\n", 90 __FUNCTION__, -err); 91 break; 92 } 93 svc_process(rqstp); 94 } 95 96 flush_signals(current); 97 svc_exit_thread(rqstp); 98 nfs_callback_info.pid = 0; 99 complete(&nfs_callback_info.stopped); 100 unlock_kernel(); 101 module_put_and_exit(0); 102 } 103 104 /* 105 * Bring up the server process if it is not already up. 106 */ 107 int nfs_callback_up(void) 108 { 109 struct svc_serv *serv = NULL; 110 int ret = 0; 111 112 lock_kernel(); 113 mutex_lock(&nfs_callback_mutex); 114 if (nfs_callback_info.users++ || nfs_callback_info.pid != 0) 115 goto out; 116 init_completion(&nfs_callback_info.started); 117 init_completion(&nfs_callback_info.stopped); 118 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); 119 ret = -ENOMEM; 120 if (!serv) 121 goto out_err; 122 123 ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport, 124 SVC_SOCK_ANONYMOUS); 125 if (ret <= 0) 126 goto out_err; 127 nfs_callback_tcpport = ret; 128 dprintk("Callback port = 0x%x\n", nfs_callback_tcpport); 129 130 ret = svc_create_thread(nfs_callback_svc, serv); 131 if (ret < 0) 132 goto out_err; 133 nfs_callback_info.serv = serv; 134 wait_for_completion(&nfs_callback_info.started); 135 out: 136 /* 137 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 138 * svc_create_thread increments that. So we need to call svc_destroy 139 * on both success and failure so that the refcount is 1 when the 140 * thread exits. 141 */ 142 if (serv) 143 svc_destroy(serv); 144 mutex_unlock(&nfs_callback_mutex); 145 unlock_kernel(); 146 return ret; 147 out_err: 148 dprintk("Couldn't create callback socket or server thread; err = %d\n", 149 ret); 150 nfs_callback_info.users--; 151 goto out; 152 } 153 154 /* 155 * Kill the server process if it is not already up. 156 */ 157 void nfs_callback_down(void) 158 { 159 lock_kernel(); 160 mutex_lock(&nfs_callback_mutex); 161 nfs_callback_info.users--; 162 do { 163 if (nfs_callback_info.users != 0 || nfs_callback_info.pid == 0) 164 break; 165 if (kill_proc(nfs_callback_info.pid, SIGKILL, 1) < 0) 166 break; 167 } while (wait_for_completion_timeout(&nfs_callback_info.stopped, 5*HZ) == 0); 168 mutex_unlock(&nfs_callback_mutex); 169 unlock_kernel(); 170 } 171 172 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 173 { 174 struct nfs_client *clp; 175 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 176 177 /* Don't talk to strangers */ 178 clp = nfs_find_client(svc_addr(rqstp), 4); 179 if (clp == NULL) 180 return SVC_DROP; 181 182 dprintk("%s: %s NFSv4 callback!\n", __FUNCTION__, 183 svc_print_addr(rqstp, buf, sizeof(buf))); 184 nfs_put_client(clp); 185 186 switch (rqstp->rq_authop->flavour) { 187 case RPC_AUTH_NULL: 188 if (rqstp->rq_proc != CB_NULL) 189 return SVC_DENIED; 190 break; 191 case RPC_AUTH_UNIX: 192 break; 193 case RPC_AUTH_GSS: 194 /* FIXME: RPCSEC_GSS handling? */ 195 default: 196 return SVC_DENIED; 197 } 198 return SVC_OK; 199 } 200 201 /* 202 * Define NFS4 callback program 203 */ 204 static struct svc_version *nfs4_callback_version[] = { 205 [1] = &nfs4_callback_version1, 206 }; 207 208 static struct svc_stat nfs4_callback_stats; 209 210 static struct svc_program nfs4_callback_program = { 211 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 212 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 213 .pg_vers = nfs4_callback_version, /* version table */ 214 .pg_name = "NFSv4 callback", /* service name */ 215 .pg_class = "nfs", /* authentication class */ 216 .pg_stats = &nfs4_callback_stats, 217 .pg_authenticate = nfs_callback_authenticate, 218 }; 219