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 } 125 126 dcbuf = vmemdup_user(buf, nbytes); 127 if (IS_ERR(dcbuf)) { 128 retval = PTR_ERR(dcbuf); 129 goto out; 130 } 131 132 /* what downcall errors does Venus handle ? */ 133 error = coda_downcall(vcp, hdr.opcode, dcbuf, nbytes); 134 135 kvfree(dcbuf); 136 if (error) { 137 pr_warn("%s: coda_downcall error: %d\n", 138 __func__, error); 139 retval = error; 140 goto out; 141 } 142 count = nbytes; 143 goto out; 144 } 145 146 /* Look for the message on the processing queue. */ 147 mutex_lock(&vcp->vc_mutex); 148 list_for_each(lh, &vcp->vc_processing) { 149 tmp = list_entry(lh, struct upc_req , uc_chain); 150 if (tmp->uc_unique == hdr.unique) { 151 req = tmp; 152 list_del(&req->uc_chain); 153 break; 154 } 155 } 156 mutex_unlock(&vcp->vc_mutex); 157 158 if (!req) { 159 pr_warn("%s: msg (%d, %d) not found\n", 160 __func__, hdr.opcode, hdr.unique); 161 retval = -ESRCH; 162 goto out; 163 } 164 165 /* move data into response buffer. */ 166 if (req->uc_outSize < nbytes) { 167 pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n", 168 __func__, req->uc_outSize, (long)nbytes, 169 hdr.opcode, hdr.unique); 170 nbytes = req->uc_outSize; /* don't have more space! */ 171 } 172 if (copy_from_user(req->uc_data, buf, nbytes)) { 173 req->uc_flags |= CODA_REQ_ABORT; 174 wake_up(&req->uc_sleep); 175 retval = -EFAULT; 176 goto out; 177 } 178 179 /* adjust outsize. is this useful ?? */ 180 req->uc_outSize = nbytes; 181 req->uc_flags |= CODA_REQ_WRITE; 182 count = nbytes; 183 184 /* Convert filedescriptor into a file handle */ 185 if (req->uc_opcode == CODA_OPEN_BY_FD) { 186 struct coda_open_by_fd_out *outp = 187 (struct coda_open_by_fd_out *)req->uc_data; 188 if (!outp->oh.result) { 189 outp->fh = fget(outp->fd); 190 if (!outp->fh) 191 return -EBADF; 192 } 193 } 194 195 wake_up(&req->uc_sleep); 196 out: 197 return(count ? count : retval); 198 } 199 200 /* 201 * Read a message from the kernel to Venus 202 */ 203 204 static ssize_t coda_psdev_read(struct file * file, char __user * buf, 205 size_t nbytes, loff_t *off) 206 { 207 DECLARE_WAITQUEUE(wait, current); 208 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 209 struct upc_req *req; 210 ssize_t retval = 0, count = 0; 211 212 if (nbytes == 0) 213 return 0; 214 215 mutex_lock(&vcp->vc_mutex); 216 217 add_wait_queue(&vcp->vc_waitq, &wait); 218 set_current_state(TASK_INTERRUPTIBLE); 219 220 while (list_empty(&vcp->vc_pending)) { 221 if (file->f_flags & O_NONBLOCK) { 222 retval = -EAGAIN; 223 break; 224 } 225 if (signal_pending(current)) { 226 retval = -ERESTARTSYS; 227 break; 228 } 229 mutex_unlock(&vcp->vc_mutex); 230 schedule(); 231 mutex_lock(&vcp->vc_mutex); 232 } 233 234 set_current_state(TASK_RUNNING); 235 remove_wait_queue(&vcp->vc_waitq, &wait); 236 237 if (retval) 238 goto out; 239 240 req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain); 241 list_del(&req->uc_chain); 242 243 /* Move the input args into userspace */ 244 count = req->uc_inSize; 245 if (nbytes < req->uc_inSize) { 246 pr_warn("%s: Venus read %ld bytes of %d in message\n", 247 __func__, (long)nbytes, req->uc_inSize); 248 count = nbytes; 249 } 250 251 if (copy_to_user(buf, req->uc_data, count)) 252 retval = -EFAULT; 253 254 /* If request was not a signal, enqueue and don't free */ 255 if (!(req->uc_flags & CODA_REQ_ASYNC)) { 256 req->uc_flags |= CODA_REQ_READ; 257 list_add_tail(&(req->uc_chain), &vcp->vc_processing); 258 goto out; 259 } 260 261 kvfree(req->uc_data); 262 kfree(req); 263 out: 264 mutex_unlock(&vcp->vc_mutex); 265 return (count ? count : retval); 266 } 267 268 static int coda_psdev_open(struct inode * inode, struct file * file) 269 { 270 struct venus_comm *vcp; 271 int idx, err; 272 273 if (task_active_pid_ns(current) != &init_pid_ns) 274 return -EINVAL; 275 276 if (current_user_ns() != &init_user_ns) 277 return -EINVAL; 278 279 idx = iminor(inode); 280 if (idx < 0 || idx >= MAX_CODADEVS) 281 return -ENODEV; 282 283 err = -EBUSY; 284 vcp = &coda_comms[idx]; 285 mutex_lock(&vcp->vc_mutex); 286 287 if (!vcp->vc_inuse) { 288 vcp->vc_inuse++; 289 290 INIT_LIST_HEAD(&vcp->vc_pending); 291 INIT_LIST_HEAD(&vcp->vc_processing); 292 init_waitqueue_head(&vcp->vc_waitq); 293 vcp->vc_sb = NULL; 294 vcp->vc_seq = 0; 295 296 file->private_data = vcp; 297 err = 0; 298 } 299 300 mutex_unlock(&vcp->vc_mutex); 301 return err; 302 } 303 304 305 static int coda_psdev_release(struct inode * inode, struct file * file) 306 { 307 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 308 struct upc_req *req, *tmp; 309 310 if (!vcp || !vcp->vc_inuse ) { 311 pr_warn("%s: Not open.\n", __func__); 312 return -1; 313 } 314 315 mutex_lock(&vcp->vc_mutex); 316 317 /* Wakeup clients so they can return. */ 318 list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) { 319 list_del(&req->uc_chain); 320 321 /* Async requests need to be freed here */ 322 if (req->uc_flags & CODA_REQ_ASYNC) { 323 kvfree(req->uc_data); 324 kfree(req); 325 continue; 326 } 327 req->uc_flags |= CODA_REQ_ABORT; 328 wake_up(&req->uc_sleep); 329 } 330 331 list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) { 332 list_del(&req->uc_chain); 333 334 req->uc_flags |= CODA_REQ_ABORT; 335 wake_up(&req->uc_sleep); 336 } 337 338 file->private_data = NULL; 339 vcp->vc_inuse--; 340 mutex_unlock(&vcp->vc_mutex); 341 return 0; 342 } 343 344 345 static const struct file_operations coda_psdev_fops = { 346 .owner = THIS_MODULE, 347 .read = coda_psdev_read, 348 .write = coda_psdev_write, 349 .poll = coda_psdev_poll, 350 .unlocked_ioctl = coda_psdev_ioctl, 351 .open = coda_psdev_open, 352 .release = coda_psdev_release, 353 .llseek = noop_llseek, 354 }; 355 356 static int __init init_coda_psdev(void) 357 { 358 int i, err = 0; 359 if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) { 360 pr_err("%s: unable to get major %d\n", 361 __func__, CODA_PSDEV_MAJOR); 362 return -EIO; 363 } 364 coda_psdev_class = class_create(THIS_MODULE, "coda"); 365 if (IS_ERR(coda_psdev_class)) { 366 err = PTR_ERR(coda_psdev_class); 367 goto out_chrdev; 368 } 369 for (i = 0; i < MAX_CODADEVS; i++) { 370 mutex_init(&(&coda_comms[i])->vc_mutex); 371 device_create(coda_psdev_class, NULL, 372 MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i); 373 } 374 coda_sysctl_init(); 375 goto out; 376 377 out_chrdev: 378 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 379 out: 380 return err; 381 } 382 383 MODULE_AUTHOR("Jan Harkes, Peter J. Braam"); 384 MODULE_DESCRIPTION("Coda Distributed File System VFS interface"); 385 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR); 386 MODULE_LICENSE("GPL"); 387 MODULE_VERSION("7.2"); 388 389 static int __init init_coda(void) 390 { 391 int status; 392 int i; 393 394 status = coda_init_inodecache(); 395 if (status) 396 goto out2; 397 status = init_coda_psdev(); 398 if ( status ) { 399 pr_warn("Problem (%d) in init_coda_psdev\n", status); 400 goto out1; 401 } 402 403 status = register_filesystem(&coda_fs_type); 404 if (status) { 405 pr_warn("failed to register filesystem!\n"); 406 goto out; 407 } 408 return 0; 409 out: 410 for (i = 0; i < MAX_CODADEVS; i++) 411 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); 412 class_destroy(coda_psdev_class); 413 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 414 coda_sysctl_clean(); 415 out1: 416 coda_destroy_inodecache(); 417 out2: 418 return status; 419 } 420 421 static void __exit exit_coda(void) 422 { 423 int err, i; 424 425 err = unregister_filesystem(&coda_fs_type); 426 if (err != 0) 427 pr_warn("failed to unregister filesystem\n"); 428 for (i = 0; i < MAX_CODADEVS; i++) 429 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); 430 class_destroy(coda_psdev_class); 431 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 432 coda_sysctl_clean(); 433 coda_destroy_inodecache(); 434 } 435 436 module_init(init_coda); 437 module_exit(exit_coda); 438 439