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.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 <asm/poll.h> 43 #include <asm/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 unsigned int coda_psdev_poll(struct file *file, poll_table * wait) 65 { 66 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 67 unsigned int mask = POLLOUT | POLLWRNORM; 68 69 poll_wait(file, &vcp->vc_waitq, wait); 70 mutex_lock(&vcp->vc_mutex); 71 if (!list_empty(&vcp->vc_pending)) 72 mask |= POLLIN | POLLRDNORM; 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 printk("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 printk("Coda: 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 printk("psdev_write: coda_downcall error: %d\n", error); 140 retval = error; 141 goto out; 142 } 143 count = nbytes; 144 goto out; 145 } 146 147 /* Look for the message on the processing queue. */ 148 mutex_lock(&vcp->vc_mutex); 149 list_for_each(lh, &vcp->vc_processing) { 150 tmp = list_entry(lh, struct upc_req , uc_chain); 151 if (tmp->uc_unique == hdr.unique) { 152 req = tmp; 153 list_del(&req->uc_chain); 154 break; 155 } 156 } 157 mutex_unlock(&vcp->vc_mutex); 158 159 if (!req) { 160 printk("psdev_write: msg (%d, %d) not found\n", 161 hdr.opcode, hdr.unique); 162 retval = -ESRCH; 163 goto out; 164 } 165 166 /* move data into response buffer. */ 167 if (req->uc_outSize < nbytes) { 168 printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n", 169 req->uc_outSize, (long)nbytes, 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 } 191 192 wake_up(&req->uc_sleep); 193 out: 194 return(count ? count : retval); 195 } 196 197 /* 198 * Read a message from the kernel to Venus 199 */ 200 201 static ssize_t coda_psdev_read(struct file * file, char __user * buf, 202 size_t nbytes, loff_t *off) 203 { 204 DECLARE_WAITQUEUE(wait, current); 205 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 206 struct upc_req *req; 207 ssize_t retval = 0, count = 0; 208 209 if (nbytes == 0) 210 return 0; 211 212 mutex_lock(&vcp->vc_mutex); 213 214 add_wait_queue(&vcp->vc_waitq, &wait); 215 set_current_state(TASK_INTERRUPTIBLE); 216 217 while (list_empty(&vcp->vc_pending)) { 218 if (file->f_flags & O_NONBLOCK) { 219 retval = -EAGAIN; 220 break; 221 } 222 if (signal_pending(current)) { 223 retval = -ERESTARTSYS; 224 break; 225 } 226 mutex_unlock(&vcp->vc_mutex); 227 schedule(); 228 mutex_lock(&vcp->vc_mutex); 229 } 230 231 set_current_state(TASK_RUNNING); 232 remove_wait_queue(&vcp->vc_waitq, &wait); 233 234 if (retval) 235 goto out; 236 237 req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain); 238 list_del(&req->uc_chain); 239 240 /* Move the input args into userspace */ 241 count = req->uc_inSize; 242 if (nbytes < req->uc_inSize) { 243 printk ("psdev_read: Venus read %ld bytes of %d in message\n", 244 (long)nbytes, req->uc_inSize); 245 count = nbytes; 246 } 247 248 if (copy_to_user(buf, req->uc_data, count)) 249 retval = -EFAULT; 250 251 /* If request was not a signal, enqueue and don't free */ 252 if (!(req->uc_flags & CODA_REQ_ASYNC)) { 253 req->uc_flags |= CODA_REQ_READ; 254 list_add_tail(&(req->uc_chain), &vcp->vc_processing); 255 goto out; 256 } 257 258 CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr)); 259 kfree(req); 260 out: 261 mutex_unlock(&vcp->vc_mutex); 262 return (count ? count : retval); 263 } 264 265 static int coda_psdev_open(struct inode * inode, struct file * file) 266 { 267 struct venus_comm *vcp; 268 int idx, err; 269 270 if (task_active_pid_ns(current) != &init_pid_ns) 271 return -EINVAL; 272 273 if (current_user_ns() != &init_user_ns) 274 return -EINVAL; 275 276 idx = iminor(inode); 277 if (idx < 0 || idx >= MAX_CODADEVS) 278 return -ENODEV; 279 280 err = -EBUSY; 281 vcp = &coda_comms[idx]; 282 mutex_lock(&vcp->vc_mutex); 283 284 if (!vcp->vc_inuse) { 285 vcp->vc_inuse++; 286 287 INIT_LIST_HEAD(&vcp->vc_pending); 288 INIT_LIST_HEAD(&vcp->vc_processing); 289 init_waitqueue_head(&vcp->vc_waitq); 290 vcp->vc_sb = NULL; 291 vcp->vc_seq = 0; 292 293 file->private_data = vcp; 294 err = 0; 295 } 296 297 mutex_unlock(&vcp->vc_mutex); 298 return err; 299 } 300 301 302 static int coda_psdev_release(struct inode * inode, struct file * file) 303 { 304 struct venus_comm *vcp = (struct venus_comm *) file->private_data; 305 struct upc_req *req, *tmp; 306 307 if (!vcp || !vcp->vc_inuse ) { 308 printk("psdev_release: Not open.\n"); 309 return -1; 310 } 311 312 mutex_lock(&vcp->vc_mutex); 313 314 /* Wakeup clients so they can return. */ 315 list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) { 316 list_del(&req->uc_chain); 317 318 /* Async requests need to be freed here */ 319 if (req->uc_flags & CODA_REQ_ASYNC) { 320 CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr)); 321 kfree(req); 322 continue; 323 } 324 req->uc_flags |= CODA_REQ_ABORT; 325 wake_up(&req->uc_sleep); 326 } 327 328 list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) { 329 list_del(&req->uc_chain); 330 331 req->uc_flags |= CODA_REQ_ABORT; 332 wake_up(&req->uc_sleep); 333 } 334 335 file->private_data = NULL; 336 vcp->vc_inuse--; 337 mutex_unlock(&vcp->vc_mutex); 338 return 0; 339 } 340 341 342 static const struct file_operations coda_psdev_fops = { 343 .owner = THIS_MODULE, 344 .read = coda_psdev_read, 345 .write = coda_psdev_write, 346 .poll = coda_psdev_poll, 347 .unlocked_ioctl = coda_psdev_ioctl, 348 .open = coda_psdev_open, 349 .release = coda_psdev_release, 350 .llseek = noop_llseek, 351 }; 352 353 static int init_coda_psdev(void) 354 { 355 int i, err = 0; 356 if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) { 357 printk(KERN_ERR "coda_psdev: unable to get major %d\n", 358 CODA_PSDEV_MAJOR); 359 return -EIO; 360 } 361 coda_psdev_class = class_create(THIS_MODULE, "coda"); 362 if (IS_ERR(coda_psdev_class)) { 363 err = PTR_ERR(coda_psdev_class); 364 goto out_chrdev; 365 } 366 for (i = 0; i < MAX_CODADEVS; i++) { 367 mutex_init(&(&coda_comms[i])->vc_mutex); 368 device_create(coda_psdev_class, NULL, 369 MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i); 370 } 371 coda_sysctl_init(); 372 goto out; 373 374 out_chrdev: 375 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 376 out: 377 return err; 378 } 379 380 MODULE_AUTHOR("Jan Harkes, Peter J. Braam"); 381 MODULE_DESCRIPTION("Coda Distributed File System VFS interface"); 382 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR); 383 MODULE_LICENSE("GPL"); 384 MODULE_VERSION("6.6"); 385 386 static int __init init_coda(void) 387 { 388 int status; 389 int i; 390 391 status = coda_init_inodecache(); 392 if (status) 393 goto out2; 394 status = init_coda_psdev(); 395 if ( status ) { 396 printk("Problem (%d) in init_coda_psdev\n", status); 397 goto out1; 398 } 399 400 status = register_filesystem(&coda_fs_type); 401 if (status) { 402 printk("coda: failed to register filesystem!\n"); 403 goto out; 404 } 405 return 0; 406 out: 407 for (i = 0; i < MAX_CODADEVS; i++) 408 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); 409 class_destroy(coda_psdev_class); 410 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 411 coda_sysctl_clean(); 412 out1: 413 coda_destroy_inodecache(); 414 out2: 415 return status; 416 } 417 418 static void __exit exit_coda(void) 419 { 420 int err, i; 421 422 err = unregister_filesystem(&coda_fs_type); 423 if ( err != 0 ) { 424 printk("coda: failed to unregister filesystem\n"); 425 } 426 for (i = 0; i < MAX_CODADEVS; i++) 427 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); 428 class_destroy(coda_psdev_class); 429 unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); 430 coda_sysctl_clean(); 431 coda_destroy_inodecache(); 432 } 433 434 module_init(init_coda); 435 module_exit(exit_coda); 436 437