1 /* 2 * An implementation of a loadable kernel mode driver providing 3 * multiple kernel/user space bidirectional communications links. 4 * 5 * Author: Alan Cox <alan@lxorguk.ukuu.org.uk> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * Adapted to become the Linux 2.0 Coda pseudo device 13 * Peter Braam <braam@maths.ox.ac.uk> 14 * Michael Callahan <mjc@emmy.smith.edu> 15 * 16 * Changes for Linux 2.1 17 * Copyright (c) 1997 Carnegie-Mellon University 18 */ 19 20 #include <linux/module.h> 21 #include <linux/errno.h> 22 #include <linux/kernel.h> 23 #include <linux/major.h> 24 #include <linux/time.h> 25 #include <linux/sched/signal.h> 26 #include <linux/slab.h> 27 #include <linux/ioport.h> 28 #include <linux/fcntl.h> 29 #include <linux/delay.h> 30 #include <linux/skbuff.h> 31 #include <linux/proc_fs.h> 32 #include <linux/vmalloc.h> 33 #include <linux/fs.h> 34 #include <linux/file.h> 35 #include <linux/poll.h> 36 #include <linux/init.h> 37 #include <linux/list.h> 38 #include <linux/mutex.h> 39 #include <linux/device.h> 40 #include <linux/pid_namespace.h> 41 #include <asm/io.h> 42 #include <linux/poll.h> 43 #include <linux/uaccess.h> 44 45 #include <linux/coda.h> 46 #include <linux/coda_psdev.h> 47 48 #include "coda_linux.h" 49 50 #include "coda_int.h" 51 52 /* statistics */ 53 int coda_hard; /* allows signals during upcalls */ 54 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */ 55 56 57 struct venus_comm coda_comms[MAX_CODADEVS]; 58 static struct class *coda_psdev_class; 59 60 /* 61 * Device operations 62 */ 63 64 static __poll_t coda_psdev_poll(struct file *file, poll_table * wait) 65 { 66 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 67 __poll_t mask = EPOLLOUT | EPOLLWRNORM; 68 69 poll_wait(file, &vcp->vc_waitq, wait); 70 mutex_lock(&vcp->vc_mutex); 71 if (!list_empty(&vcp->vc_pending)) 72 mask |= EPOLLIN | EPOLLRDNORM; 73 mutex_unlock(&vcp->vc_mutex); 74 75 return mask; 76 } 77 78 static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg) 79 { 80 unsigned int data; 81 82 switch(cmd) { 83 case CIOC_KERNEL_VERSION: 84 data = CODA_KERNEL_VERSION; 85 return put_user(data, (int __user *) arg); 86 default: 87 return -ENOTTY; 88 } 89 90 return 0; 91 } 92 93 /* 94 * Receive a message written by Venus to the psdev 95 */ 96 97 static ssize_t coda_psdev_write(struct file *file, const char __user *buf, 98 size_t nbytes, loff_t *off) 99 { 100 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 101 struct upc_req *req = NULL; 102 struct upc_req *tmp; 103 struct list_head *lh; 104 struct coda_in_hdr hdr; 105 ssize_t retval = 0, count = 0; 106 int error; 107 108 /* Peek at the opcode, uniquefier */ 109 if (copy_from_user(&hdr, buf, 2 * sizeof(u_long))) 110 return -EFAULT; 111 112 if (DOWNCALL(hdr.opcode)) { 113 union outputArgs *dcbuf; 114 int size = sizeof(*dcbuf); 115 116 if ( nbytes < sizeof(struct coda_out_hdr) ) { 117 pr_warn("coda_downcall opc %d uniq %d, not enough!\n", 118 hdr.opcode, hdr.unique); 119 count = nbytes; 120 goto out; 121 } 122 if ( nbytes > size ) { 123 pr_warn("downcall opc %d, uniq %d, too much!", 124 hdr.opcode, hdr.unique); 125 nbytes = size; 126 } 127 CODA_ALLOC(dcbuf, union outputArgs *, nbytes); 128 if (copy_from_user(dcbuf, buf, nbytes)) { 129 CODA_FREE(dcbuf, nbytes); 130 retval = -EFAULT; 131 goto out; 132 } 133 134 /* what downcall errors does Venus handle ? */ 135 error = coda_downcall(vcp, hdr.opcode, dcbuf); 136 137 CODA_FREE(dcbuf, nbytes); 138 if (error) { 139 pr_warn("%s: coda_downcall error: %d\n", 140 __func__, error); 141 retval = error; 142 goto out; 143 } 144 count = nbytes; 145 goto out; 146 } 147 148 /* Look for the message on the processing queue. */ 149 mutex_lock(&vcp->vc_mutex); 150 list_for_each(lh, &vcp->vc_processing) { 151 tmp = list_entry(lh, struct upc_req , uc_chain); 152 if (tmp->uc_unique == hdr.unique) { 153 req = tmp; 154 list_del(&req->uc_chain); 155 break; 156 } 157 } 158 mutex_unlock(&vcp->vc_mutex); 159 160 if (!req) { 161 pr_warn("%s: msg (%d, %d) not found\n", 162 __func__, hdr.opcode, hdr.unique); 163 retval = -ESRCH; 164 goto out; 165 } 166 167 /* move data into response buffer. */ 168 if (req->uc_outSize < nbytes) { 169 pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n", 170 __func__, req->uc_outSize, (long)nbytes, 171 hdr.opcode, hdr.unique); 172 nbytes = req->uc_outSize; /* don't have more space! */ 173 } 174 if (copy_from_user(req->uc_data, buf, nbytes)) { 175 req->uc_flags |= CODA_REQ_ABORT; 176 wake_up(&req->uc_sleep); 177 retval = -EFAULT; 178 goto out; 179 } 180 181 /* adjust outsize. is this useful ?? */ 182 req->uc_outSize = nbytes; 183 req->uc_flags |= CODA_REQ_WRITE; 184 count = nbytes; 185 186 /* Convert filedescriptor into a file handle */ 187 if (req->uc_opcode == CODA_OPEN_BY_FD) { 188 struct coda_open_by_fd_out *outp = 189 (struct coda_open_by_fd_out *)req->uc_data; 190 if (!outp->oh.result) 191 outp->fh = fget(outp->fd); 192 } 193 194 wake_up(&req->uc_sleep); 195 out: 196 return(count ? count : retval); 197 } 198 199 /* 200 * Read a message from the kernel to Venus 201 */ 202 203 static ssize_t coda_psdev_read(struct file * file, char __user * buf, 204 size_t nbytes, loff_t *off) 205 { 206 DECLARE_WAITQUEUE(wait, current); 207 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 208 struct upc_req *req; 209 ssize_t retval = 0, count = 0; 210 211 if (nbytes == 0) 212 return 0; 213 214 mutex_lock(&vcp->vc_mutex); 215 216 add_wait_queue(&vcp->vc_waitq, &wait); 217 set_current_state(TASK_INTERRUPTIBLE); 218 219 while (list_empty(&vcp->vc_pending)) { 220 if (file->f_flags & O_NONBLOCK) { 221 retval = -EAGAIN; 222 break; 223 } 224 if (signal_pending(current)) { 225 retval = -ERESTARTSYS; 226 break; 227 } 228 mutex_unlock(&vcp->vc_mutex); 229 schedule(); 230 mutex_lock(&vcp->vc_mutex); 231 } 232 233 set_current_state(TASK_RUNNING); 234 remove_wait_queue(&vcp->vc_waitq, &wait); 235 236 if (retval) 237 goto out; 238 239 req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain); 240 list_del(&req->uc_chain); 241 242 /* Move the input args into userspace */ 243 count = req->uc_inSize; 244 if (nbytes < req->uc_inSize) { 245 pr_warn("%s: Venus read %ld bytes of %d in message\n", 246 __func__, (long)nbytes, req->uc_inSize); 247 count = nbytes; 248 } 249 250 if (copy_to_user(buf, req->uc_data, count)) 251 retval = -EFAULT; 252 253 /* If request was not a signal, enqueue and don't free */ 254 if (!(req->uc_flags & CODA_REQ_ASYNC)) { 255 req->uc_flags |= CODA_REQ_READ; 256 list_add_tail(&(req->uc_chain), &vcp->vc_processing); 257 goto out; 258 } 259 260 CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr)); 261 kfree(req); 262 out: 263 mutex_unlock(&vcp->vc_mutex); 264 return (count ? count : retval); 265 } 266 267 static int coda_psdev_open(struct inode * inode, struct file * file) 268 { 269 struct venus_comm *vcp; 270 int idx, err; 271 272 if (task_active_pid_ns(current) != &init_pid_ns) 273 return -EINVAL; 274 275 if (current_user_ns() != &init_user_ns) 276 return -EINVAL; 277 278 idx = iminor(inode); 279 if (idx < 0 || idx >= MAX_CODADEVS) 280 return -ENODEV; 281 282 err = -EBUSY; 283 vcp = &coda_comms[idx]; 284 mutex_lock(&vcp->vc_mutex); 285 286 if (!vcp->vc_inuse) { 287 vcp->vc_inuse++; 288 289 INIT_LIST_HEAD(&vcp->vc_pending); 290 INIT_LIST_HEAD(&vcp->vc_processing); 291 init_waitqueue_head(&vcp->vc_waitq); 292 vcp->vc_sb = NULL; 293 vcp->vc_seq = 0; 294 295 file->private_data = vcp; 296 err = 0; 297 } 298 299 mutex_unlock(&vcp->vc_mutex); 300 return err; 301 } 302 303 304 static int coda_psdev_release(struct inode * inode, struct file * file) 305 { 306 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 307 struct upc_req *req, *tmp; 308 309 if (!vcp || !vcp->vc_inuse ) { 310 pr_warn("%s: Not open.\n", __func__); 311 return -1; 312 } 313 314 mutex_lock(&vcp->vc_mutex); 315 316 /* Wakeup clients so they can return. */ 317 list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) { 318 list_del(&req->uc_chain); 319 320 /* Async requests need to be freed here */ 321 if (req->uc_flags & CODA_REQ_ASYNC) { 322 CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr)); 323 kfree(req); 324 continue; 325 } 326 req->uc_flags |= CODA_REQ_ABORT; 327 wake_up(&req->uc_sleep); 328 } 329 330 list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) { 331 list_del(&req->uc_chain); 332 333 req->uc_flags |= CODA_REQ_ABORT; 334 wake_up(&req->uc_sleep); 335 } 336 337 file->private_data = NULL; 338 vcp->vc_inuse--; 339 mutex_unlock(&vcp->vc_mutex); 340 return 0; 341 } 342 343 344 static const struct file_operations coda_psdev_fops = { 345 .owner = THIS_MODULE, 346 .read = coda_psdev_read, 347 .write = coda_psdev_write, 348 .poll = coda_psdev_poll, 349 .unlocked_ioctl = coda_psdev_ioctl, 350 .open = coda_psdev_open, 351 .release = coda_psdev_release, 352 .llseek = noop_llseek, 353 }; 354 355 static int init_coda_psdev(void) 356 { 357 int i, err = 0; 358 if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) { 359 pr_err("%s: unable to get major %d\n", 360 __func__, CODA_PSDEV_MAJOR); 361 return -EIO; 362 } 363 coda_psdev_class = class_create(THIS_MODULE, "coda"); 364 if (IS_ERR(coda_psdev_class)) { 365 err = PTR_ERR(coda_psdev_class); 366 goto out_chrdev; 367 } 368 for (i = 0; i < MAX_CODADEVS; i++) { 369 mutex_init(&(&coda_comms[i])->vc_mutex); 370 device_create(coda_psdev_class, NULL, 371 MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i); 372 } 373 coda_sysctl_init(); 374 goto out; 375 376 out_chrdev: 377 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 378 out: 379 return err; 380 } 381 382 MODULE_AUTHOR("Jan Harkes, Peter J. Braam"); 383 MODULE_DESCRIPTION("Coda Distributed File System VFS interface"); 384 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR); 385 MODULE_LICENSE("GPL"); 386 MODULE_VERSION("6.6"); 387 388 static int __init init_coda(void) 389 { 390 int status; 391 int i; 392 393 status = coda_init_inodecache(); 394 if (status) 395 goto out2; 396 status = init_coda_psdev(); 397 if ( status ) { 398 pr_warn("Problem (%d) in init_coda_psdev\n", status); 399 goto out1; 400 } 401 402 status = register_filesystem(&coda_fs_type); 403 if (status) { 404 pr_warn("failed to register filesystem!\n"); 405 goto out; 406 } 407 return 0; 408 out: 409 for (i = 0; i < MAX_CODADEVS; i++) 410 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); 411 class_destroy(coda_psdev_class); 412 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 413 coda_sysctl_clean(); 414 out1: 415 coda_destroy_inodecache(); 416 out2: 417 return status; 418 } 419 420 static void __exit exit_coda(void) 421 { 422 int err, i; 423 424 err = unregister_filesystem(&coda_fs_type); 425 if (err != 0) 426 pr_warn("failed to unregister filesystem\n"); 427 for (i = 0; i < MAX_CODADEVS; i++) 428 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); 429 class_destroy(coda_psdev_class); 430 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 431 coda_sysctl_clean(); 432 coda_destroy_inodecache(); 433 } 434 435 module_init(init_coda); 436 module_exit(exit_coda); 437 438