fs/coda/psdev.c

   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                         if (!outp->fh)
 193                                 return -EBADF;
 194                 }
 195         }
 196
 197         wake_up(&req->uc_sleep);
 198 out:
 199         return(count ? count : retval);
 200 }
 201
 202 /*
 203  *      Read a message from the kernel to Venus
 204  */
 205
 206 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
 207                                size_t nbytes, loff_t *off)
 208 {
 209         DECLARE_WAITQUEUE(wait, current);
 210         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 211         struct upc_req *req;
 212         ssize_t retval = 0, count = 0;
 213
 214         if (nbytes == 0)
 215                 return 0;
 216
 217         mutex_lock(&vcp->vc_mutex);
 218
 219         add_wait_queue(&vcp->vc_waitq, &wait);
 220         set_current_state(TASK_INTERRUPTIBLE);
 221
 222         while (list_empty(&vcp->vc_pending)) {
 223                 if (file->f_flags & O_NONBLOCK) {
 224                         retval = -EAGAIN;
 225                         break;
 226                 }
 227                 if (signal_pending(current)) {
 228                         retval = -ERESTARTSYS;
 229                         break;
 230                 }
 231                 mutex_unlock(&vcp->vc_mutex);
 232                 schedule();
 233                 mutex_lock(&vcp->vc_mutex);
 234         }
 235
 236         set_current_state(TASK_RUNNING);
 237         remove_wait_queue(&vcp->vc_waitq, &wait);
 238
 239         if (retval)
 240                 goto out;
 241
 242         req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
 243         list_del(&req->uc_chain);
 244
 245         /* Move the input args into userspace */
 246         count = req->uc_inSize;
 247         if (nbytes < req->uc_inSize) {
 248                 pr_warn("%s: Venus read %ld bytes of %d in message\n",
 249                         __func__, (long)nbytes, req->uc_inSize);
 250                 count = nbytes;
 251         }
 252
 253         if (copy_to_user(buf, req->uc_data, count))
 254                 retval = -EFAULT;
 255
 256         /* If request was not a signal, enqueue and don't free */
 257         if (!(req->uc_flags & CODA_REQ_ASYNC)) {
 258                 req->uc_flags |= CODA_REQ_READ;
 259                 list_add_tail(&(req->uc_chain), &vcp->vc_processing);
 260                 goto out;
 261         }
 262
 263         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 264         kfree(req);
 265 out:
 266         mutex_unlock(&vcp->vc_mutex);
 267         return (count ? count : retval);
 268 }
 269
 270 static int coda_psdev_open(struct inode * inode, struct file * file)
 271 {
 272         struct venus_comm *vcp;
 273         int idx, err;
 274
 275         if (task_active_pid_ns(current) != &init_pid_ns)
 276                 return -EINVAL;
 277
 278         if (current_user_ns() != &init_user_ns)
 279                 return -EINVAL;
 280
 281         idx = iminor(inode);
 282         if (idx < 0 || idx >= MAX_CODADEVS)
 283                 return -ENODEV;
 284
 285         err = -EBUSY;
 286         vcp = &coda_comms[idx];
 287         mutex_lock(&vcp->vc_mutex);
 288
 289         if (!vcp->vc_inuse) {
 290                 vcp->vc_inuse++;
 291
 292                 INIT_LIST_HEAD(&vcp->vc_pending);
 293                 INIT_LIST_HEAD(&vcp->vc_processing);
 294                 init_waitqueue_head(&vcp->vc_waitq);
 295                 vcp->vc_sb = NULL;
 296                 vcp->vc_seq = 0;
 297
 298                 file->private_data = vcp;
 299                 err = 0;
 300         }
 301
 302         mutex_unlock(&vcp->vc_mutex);
 303         return err;
 304 }
 305
 306
 307 static int coda_psdev_release(struct inode * inode, struct file * file)
 308 {
 309         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 310         struct upc_req *req, *tmp;
 311
 312         if (!vcp || !vcp->vc_inuse ) {
 313                 pr_warn("%s: Not open.\n", __func__);
 314                 return -1;
 315         }
 316
 317         mutex_lock(&vcp->vc_mutex);
 318
 319         /* Wakeup clients so they can return. */
 320         list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
 321                 list_del(&req->uc_chain);
 322
 323                 /* Async requests need to be freed here */
 324                 if (req->uc_flags & CODA_REQ_ASYNC) {
 325                         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 326                         kfree(req);
 327                         continue;
 328                 }
 329                 req->uc_flags |= CODA_REQ_ABORT;
 330                 wake_up(&req->uc_sleep);
 331         }
 332
 333         list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
 334                 list_del(&req->uc_chain);
 335
 336                 req->uc_flags |= CODA_REQ_ABORT;
 337                 wake_up(&req->uc_sleep);
 338         }
 339
 340         file->private_data = NULL;
 341         vcp->vc_inuse--;
 342         mutex_unlock(&vcp->vc_mutex);
 343         return 0;
 344 }
 345
 346
 347 static const struct file_operations coda_psdev_fops = {
 348         .owner          = THIS_MODULE,
 349         .read           = coda_psdev_read,
 350         .write          = coda_psdev_write,
 351         .poll           = coda_psdev_poll,
 352         .unlocked_ioctl = coda_psdev_ioctl,
 353         .open           = coda_psdev_open,
 354         .release        = coda_psdev_release,
 355         .llseek         = noop_llseek,
 356 };
 357
 358 static int init_coda_psdev(void)
 359 {
 360         int i, err = 0;
 361         if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
 362                 pr_err("%s: unable to get major %d\n",
 363                        __func__, CODA_PSDEV_MAJOR);
 364               return -EIO;
 365         }
 366         coda_psdev_class = class_create(THIS_MODULE, "coda");
 367         if (IS_ERR(coda_psdev_class)) {
 368                 err = PTR_ERR(coda_psdev_class);
 369                 goto out_chrdev;
 370         }
 371         for (i = 0; i < MAX_CODADEVS; i++) {
 372                 mutex_init(&(&coda_comms[i])->vc_mutex);
 373                 device_create(coda_psdev_class, NULL,
 374                               MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
 375         }
 376         coda_sysctl_init();
 377         goto out;
 378
 379 out_chrdev:
 380         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 381 out:
 382         return err;
 383 }
 384
 385 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
 386 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
 387 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
 388 MODULE_LICENSE("GPL");
 389 MODULE_VERSION("6.6");
 390
 391 static int __init init_coda(void)
 392 {
 393         int status;
 394         int i;
 395
 396         status = coda_init_inodecache();
 397         if (status)
 398                 goto out2;
 399         status = init_coda_psdev();
 400         if ( status ) {
 401                 pr_warn("Problem (%d) in init_coda_psdev\n", status);
 402                 goto out1;
 403         }
 404
 405         status = register_filesystem(&coda_fs_type);
 406         if (status) {
 407                 pr_warn("failed to register filesystem!\n");
 408                 goto out;
 409         }
 410         return 0;
 411 out:
 412         for (i = 0; i < MAX_CODADEVS; i++)
 413                 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 414         class_destroy(coda_psdev_class);
 415         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 416         coda_sysctl_clean();
 417 out1:
 418         coda_destroy_inodecache();
 419 out2:
 420         return status;
 421 }
 422
 423 static void __exit exit_coda(void)
 424 {
 425         int err, i;
 426
 427         err = unregister_filesystem(&coda_fs_type);
 428         if (err != 0)
 429                 pr_warn("failed to unregister filesystem\n");
 430         for (i = 0; i < MAX_CODADEVS; i++)
 431                 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 432         class_destroy(coda_psdev_class);
 433         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 434         coda_sysctl_clean();
 435         coda_destroy_inodecache();
 436 }
 437
 438 module_init(init_coda);
 439 module_exit(exit_coda);
 440