1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * An implementation of a loadable kernel mode driver providing 4 * multiple kernel/user space bidirectional communications links. 5 * 6 * Author: Alan Cox <alan@lxorguk.ukuu.org.uk> 7 * 8 * Adapted to become the Linux 2.0 Coda pseudo device 9 * Peter Braam <braam@maths.ox.ac.uk> 10 * Michael Callahan <mjc@emmy.smith.edu> 11 * 12 * Changes for Linux 2.1 13 * Copyright (c) 1997 Carnegie-Mellon University 14 */ 15 16 #include <linux/module.h> 17 #include <linux/errno.h> 18 #include <linux/kernel.h> 19 #include <linux/major.h> 20 #include <linux/time.h> 21 #include <linux/sched/signal.h> 22 #include <linux/slab.h> 23 #include <linux/ioport.h> 24 #include <linux/fcntl.h> 25 #include <linux/delay.h> 26 #include <linux/skbuff.h> 27 #include <linux/proc_fs.h> 28 #include <linux/vmalloc.h> 29 #include <linux/fs.h> 30 #include <linux/file.h> 31 #include <linux/poll.h> 32 #include <linux/init.h> 33 #include <linux/list.h> 34 #include <linux/mutex.h> 35 #include <linux/device.h> 36 #include <linux/pid_namespace.h> 37 #include <asm/io.h> 38 #include <linux/uaccess.h> 39 40 #include <linux/coda.h> 41 #include "coda_psdev.h" 42 #include "coda_linux.h" 43 44 #include "coda_int.h" 45 46 /* statistics */ 47 int coda_hard; /* allows signals during upcalls */ 48 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */ 49 50 51 struct venus_comm coda_comms[MAX_CODADEVS]; 52 static struct class *coda_psdev_class; 53 54 /* 55 * Device operations 56 */ 57 58 static __poll_t coda_psdev_poll(struct file *file, poll_table * wait) 59 { 60 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 61 __poll_t mask = EPOLLOUT | EPOLLWRNORM; 62 63 poll_wait(file, &vcp->vc_waitq, wait); 64 mutex_lock(&vcp->vc_mutex); 65 if (!list_empty(&vcp->vc_pending)) 66 mask |= EPOLLIN | EPOLLRDNORM; 67 mutex_unlock(&vcp->vc_mutex); 68 69 return mask; 70 } 71 72 static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg) 73 { 74 unsigned int data; 75 76 switch(cmd) { 77 case CIOC_KERNEL_VERSION: 78 data = CODA_KERNEL_VERSION; 79 return put_user(data, (int __user *) arg); 80 default: 81 return -ENOTTY; 82 } 83 84 return 0; 85 } 86 87 /* 88 * Receive a message written by Venus to the psdev 89 */ 90 91 static ssize_t coda_psdev_write(struct file *file, const char __user *buf, 92 size_t nbytes, loff_t *off) 93 { 94 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 95 struct upc_req *req = NULL; 96 struct upc_req *tmp; 97 struct list_head *lh; 98 struct coda_in_hdr hdr; 99 ssize_t retval = 0, count = 0; 100 int error; 101 102 /* make sure there is enough to copy out the (opcode, unique) values */ 103 if (nbytes < (2 * sizeof(u_int32_t))) 104 return -EINVAL; 105 106 /* Peek at the opcode, uniquefier */ 107 if (copy_from_user(&hdr, buf, 2 * sizeof(u_int32_t))) 108 return -EFAULT; 109 110 if (DOWNCALL(hdr.opcode)) { 111 union outputArgs *dcbuf; 112 int size = sizeof(*dcbuf); 113 114 if ( nbytes < sizeof(struct coda_out_hdr) ) { 115 pr_warn("coda_downcall opc %d uniq %d, not enough!\n", 116 hdr.opcode, hdr.unique); 117 count = nbytes; 118 goto out; 119 } 120 if ( nbytes > size ) { 121 pr_warn("downcall opc %d, uniq %d, too much!", 122 hdr.opcode, hdr.unique); 123 nbytes = size; 124 } 125 dcbuf = kvmalloc(nbytes, GFP_KERNEL); 126 if (!dcbuf) { 127 retval = -ENOMEM; 128 goto out; 129 } 130 if (copy_from_user(dcbuf, buf, nbytes)) { 131 kvfree(dcbuf); 132 retval = -EFAULT; 133 goto out; 134 } 135 136 /* what downcall errors does Venus handle ? */ 137 error = coda_downcall(vcp, hdr.opcode, dcbuf, nbytes); 138 139 kvfree(dcbuf); 140 if (error) { 141 pr_warn("%s: coda_downcall error: %d\n", 142 __func__, error); 143 retval = error; 144 goto out; 145 } 146 count = nbytes; 147 goto out; 148 } 149 150 /* Look for the message on the processing queue. */ 151 mutex_lock(&vcp->vc_mutex); 152 list_for_each(lh, &vcp->vc_processing) { 153 tmp = list_entry(lh, struct upc_req , uc_chain); 154 if (tmp->uc_unique == hdr.unique) { 155 req = tmp; 156 list_del(&req->uc_chain); 157 break; 158 } 159 } 160 mutex_unlock(&vcp->vc_mutex); 161 162 if (!req) { 163 pr_warn("%s: msg (%d, %d) not found\n", 164 __func__, hdr.opcode, hdr.unique); 165 retval = -ESRCH; 166 goto out; 167 } 168 169 /* move data into response buffer. */ 170 if (req->uc_outSize < nbytes) { 171 pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n", 172 __func__, req->uc_outSize, (long)nbytes, 173 hdr.opcode, hdr.unique); 174 nbytes = req->uc_outSize; /* don't have more space! */ 175 } 176 if (copy_from_user(req->uc_data, buf, nbytes)) { 177 req->uc_flags |= CODA_REQ_ABORT; 178 wake_up(&req->uc_sleep); 179 retval = -EFAULT; 180 goto out; 181 } 182 183 /* adjust outsize. is this useful ?? */ 184 req->uc_outSize = nbytes; 185 req->uc_flags |= CODA_REQ_WRITE; 186 count = nbytes; 187 188 /* Convert filedescriptor into a file handle */ 189 if (req->uc_opcode == CODA_OPEN_BY_FD) { 190 struct coda_open_by_fd_out *outp = 191 (struct coda_open_by_fd_out *)req->uc_data; 192 if (!outp->oh.result) { 193 outp->fh = fget(outp->fd); 194 if (!outp->fh) 195 return -EBADF; 196 } 197 } 198 199 wake_up(&req->uc_sleep); 200 out: 201 return(count ? count : retval); 202 } 203 204 /* 205 * Read a message from the kernel to Venus 206 */ 207 208 static ssize_t coda_psdev_read(struct file * file, char __user * buf, 209 size_t nbytes, loff_t *off) 210 { 211 DECLARE_WAITQUEUE(wait, current); 212 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 213 struct upc_req *req; 214 ssize_t retval = 0, count = 0; 215 216 if (nbytes == 0) 217 return 0; 218 219 mutex_lock(&vcp->vc_mutex); 220 221 add_wait_queue(&vcp->vc_waitq, &wait); 222 set_current_state(TASK_INTERRUPTIBLE); 223 224 while (list_empty(&vcp->vc_pending)) { 225 if (file->f_flags & O_NONBLOCK) { 226 retval = -EAGAIN; 227 break; 228 } 229 if (signal_pending(current)) { 230 retval = -ERESTARTSYS; 231 break; 232 } 233 mutex_unlock(&vcp->vc_mutex); 234 schedule(); 235 mutex_lock(&vcp->vc_mutex); 236 } 237 238 set_current_state(TASK_RUNNING); 239 remove_wait_queue(&vcp->vc_waitq, &wait); 240 241 if (retval) 242 goto out; 243 244 req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain); 245 list_del(&req->uc_chain); 246 247 /* Move the input args into userspace */ 248 count = req->uc_inSize; 249 if (nbytes < req->uc_inSize) { 250 pr_warn("%s: Venus read %ld bytes of %d in message\n", 251 __func__, (long)nbytes, req->uc_inSize); 252 count = nbytes; 253 } 254 255 if (copy_to_user(buf, req->uc_data, count)) 256 retval = -EFAULT; 257 258 /* If request was not a signal, enqueue and don't free */ 259 if (!(req->uc_flags & CODA_REQ_ASYNC)) { 260 req->uc_flags |= CODA_REQ_READ; 261 list_add_tail(&(req->uc_chain), &vcp->vc_processing); 262 goto out; 263 } 264 265 kvfree(req->uc_data); 266 kfree(req); 267 out: 268 mutex_unlock(&vcp->vc_mutex); 269 return (count ? count : retval); 270 } 271 272 static int coda_psdev_open(struct inode * inode, struct file * file) 273 { 274 struct venus_comm *vcp; 275 int idx, err; 276 277 if (task_active_pid_ns(current) != &init_pid_ns) 278 return -EINVAL; 279 280 if (current_user_ns() != &init_user_ns) 281 return -EINVAL; 282 283 idx = iminor(inode); 284 if (idx < 0 || idx >= MAX_CODADEVS) 285 return -ENODEV; 286 287 err = -EBUSY; 288 vcp = &coda_comms[idx]; 289 mutex_lock(&vcp->vc_mutex); 290 291 if (!vcp->vc_inuse) { 292 vcp->vc_inuse++; 293 294 INIT_LIST_HEAD(&vcp->vc_pending); 295 INIT_LIST_HEAD(&vcp->vc_processing); 296 init_waitqueue_head(&vcp->vc_waitq); 297 vcp->vc_sb = NULL; 298 vcp->vc_seq = 0; 299 300 file->private_data = vcp; 301 err = 0; 302 } 303 304 mutex_unlock(&vcp->vc_mutex); 305 return err; 306 } 307 308 309 static int coda_psdev_release(struct inode * inode, struct file * file) 310 { 311 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 312 struct upc_req *req, *tmp; 313 314 if (!vcp || !vcp->vc_inuse ) { 315 pr_warn("%s: Not open.\n", __func__); 316 return -1; 317 } 318 319 mutex_lock(&vcp->vc_mutex); 320 321 /* Wakeup clients so they can return. */ 322 list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) { 323 list_del(&req->uc_chain); 324 325 /* Async requests need to be freed here */ 326 if (req->uc_flags & CODA_REQ_ASYNC) { 327 kvfree(req->uc_data); 328 kfree(req); 329 continue; 330 } 331 req->uc_flags |= CODA_REQ_ABORT; 332 wake_up(&req->uc_sleep); 333 } 334 335 list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) { 336 list_del(&req->uc_chain); 337 338 req->uc_flags |= CODA_REQ_ABORT; 339 wake_up(&req->uc_sleep); 340 } 341 342 file->private_data = NULL; 343 vcp->vc_inuse--; 344 mutex_unlock(&vcp->vc_mutex); 345 return 0; 346 } 347 348 349 static const struct file_operations coda_psdev_fops = { 350 .owner = THIS_MODULE, 351 .read = coda_psdev_read, 352 .write = coda_psdev_write, 353 .poll = coda_psdev_poll, 354 .unlocked_ioctl = coda_psdev_ioctl, 355 .open = coda_psdev_open, 356 .release = coda_psdev_release, 357 .llseek = noop_llseek, 358 }; 359 360 static int __init init_coda_psdev(void) 361 { 362 int i, err = 0; 363 if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) { 364 pr_err("%s: unable to get major %d\n", 365 __func__, CODA_PSDEV_MAJOR); 366 return -EIO; 367 } 368 coda_psdev_class = class_create(THIS_MODULE, "coda"); 369 if (IS_ERR(coda_psdev_class)) { 370 err = PTR_ERR(coda_psdev_class); 371 goto out_chrdev; 372 } 373 for (i = 0; i < MAX_CODADEVS; i++) { 374 mutex_init(&(&coda_comms[i])->vc_mutex); 375 device_create(coda_psdev_class, NULL, 376 MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i); 377 } 378 coda_sysctl_init(); 379 goto out; 380 381 out_chrdev: 382 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 383 out: 384 return err; 385 } 386 387 MODULE_AUTHOR("Jan Harkes, Peter J. Braam"); 388 MODULE_DESCRIPTION("Coda Distributed File System VFS interface"); 389 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR); 390 MODULE_LICENSE("GPL"); 391 MODULE_VERSION("7.0"); 392 393 static int __init init_coda(void) 394 { 395 int status; 396 int i; 397 398 status = coda_init_inodecache(); 399 if (status) 400 goto out2; 401 status = init_coda_psdev(); 402 if ( status ) { 403 pr_warn("Problem (%d) in init_coda_psdev\n", status); 404 goto out1; 405 } 406 407 status = register_filesystem(&coda_fs_type); 408 if (status) { 409 pr_warn("failed to register filesystem!\n"); 410 goto out; 411 } 412 return 0; 413 out: 414 for (i = 0; i < MAX_CODADEVS; i++) 415 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); 416 class_destroy(coda_psdev_class); 417 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 418 coda_sysctl_clean(); 419 out1: 420 coda_destroy_inodecache(); 421 out2: 422 return status; 423 } 424 425 static void __exit exit_coda(void) 426 { 427 int err, i; 428 429 err = unregister_filesystem(&coda_fs_type); 430 if (err != 0) 431 pr_warn("failed to unregister filesystem\n"); 432 for (i = 0; i < MAX_CODADEVS; i++) 433 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); 434 class_destroy(coda_psdev_class); 435 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 436 coda_sysctl_clean(); 437 coda_destroy_inodecache(); 438 } 439 440 module_init(init_coda); 441 module_exit(exit_coda); 442 443