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         }
 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