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   1 /*
   2  * net/sunrpc/rpc_pipe.c
   3  *
   4  * Userland/kernel interface for rpcauth_gss.
   5  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
   6  * and fs/sysfs/inode.c
   7  *
   8  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
   9  *
  10  */
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/string.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/mount.h>
  16 #include <linux/namei.h>
  17 #include <linux/fsnotify.h>
  18 #include <linux/kernel.h>
  19
  20 #include <asm/ioctls.h>
  21 #include <linux/fs.h>
  22 #include <linux/poll.h>
  23 #include <linux/wait.h>
  24 #include <linux/seq_file.h>
  25
  26 #include <linux/sunrpc/clnt.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/sunrpc/rpc_pipe_fs.h>
  29
  30 static struct vfsmount *rpc_mount __read_mostly;
  31 static int rpc_mount_count;
  32
  33 static struct file_system_type rpc_pipe_fs_type;
  34
  35
  36 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  37
  38 #define RPC_UPCALL_TIMEOUT (30*HZ)
  39
  40 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
  41                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  42 {
  43         struct rpc_pipe_msg *msg;
  44
  45         if (list_empty(head))
  46                 return;
  47         do {
  48                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  49                 list_del(&msg->list);
  50                 msg->errno = err;
  51                 destroy_msg(msg);
  52         } while (!list_empty(head));
  53         wake_up(&rpci->waitq);
  54 }
  55
  56 static void
  57 rpc_timeout_upcall_queue(struct work_struct *work)
  58 {
  59         LIST_HEAD(free_list);
  60         struct rpc_inode *rpci =
  61                 container_of(work, struct rpc_inode, queue_timeout.work);
  62         struct inode *inode = &rpci->vfs_inode;
  63         void (*destroy_msg)(struct rpc_pipe_msg *);
  64
  65         spin_lock(&inode->i_lock);
  66         if (rpci->ops == NULL) {
  67                 spin_unlock(&inode->i_lock);
  68                 return;
  69         }
  70         destroy_msg = rpci->ops->destroy_msg;
  71         if (rpci->nreaders == 0) {
  72                 list_splice_init(&rpci->pipe, &free_list);
  73                 rpci->pipelen = 0;
  74         }
  75         spin_unlock(&inode->i_lock);
  76         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
  77 }
  78
  79 /**
  80  * rpc_queue_upcall
  81  * @inode: inode of upcall pipe on which to queue given message
  82  * @msg: message to queue
  83  *
  84  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
  85  * A userspace process may then later read the upcall by performing a
  86  * read on an open file for this inode.  It is up to the caller to
  87  * initialize the fields of @msg (other than @msg->list) appropriately.
  88  */
  89 int
  90 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  91 {
  92         struct rpc_inode *rpci = RPC_I(inode);
  93         int res = -EPIPE;
  94
  95         spin_lock(&inode->i_lock);
  96         if (rpci->ops == NULL)
  97                 goto out;
  98         if (rpci->nreaders) {
  99                 list_add_tail(&msg->list, &rpci->pipe);
 100                 rpci->pipelen += msg->len;
 101                 res = 0;
 102         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 103                 if (list_empty(&rpci->pipe))
 104                         queue_delayed_work(rpciod_workqueue,
 105                                         &rpci->queue_timeout,
 106                                         RPC_UPCALL_TIMEOUT);
 107                 list_add_tail(&msg->list, &rpci->pipe);
 108                 rpci->pipelen += msg->len;
 109                 res = 0;
 110         }
 111 out:
 112         spin_unlock(&inode->i_lock);
 113         wake_up(&rpci->waitq);
 114         return res;
 115 }
 116 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 117
 118 static inline void
 119 rpc_inode_setowner(struct inode *inode, void *private)
 120 {
 121         RPC_I(inode)->private = private;
 122 }
 123
 124 static void
 125 rpc_close_pipes(struct inode *inode)
 126 {
 127         struct rpc_inode *rpci = RPC_I(inode);
 128         const struct rpc_pipe_ops *ops;
 129         int need_release;
 130
 131         mutex_lock(&inode->i_mutex);
 132         ops = rpci->ops;
 133         if (ops != NULL) {
 134                 LIST_HEAD(free_list);
 135                 spin_lock(&inode->i_lock);
 136                 need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
 137                 rpci->nreaders = 0;
 138                 list_splice_init(&rpci->in_upcall, &free_list);
 139                 list_splice_init(&rpci->pipe, &free_list);
 140                 rpci->pipelen = 0;
 141                 rpci->ops = NULL;
 142                 spin_unlock(&inode->i_lock);
 143                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 144                 rpci->nwriters = 0;
 145                 if (need_release && ops->release_pipe)
 146                         ops->release_pipe(inode);
 147                 cancel_delayed_work_sync(&rpci->queue_timeout);
 148         }
 149         rpc_inode_setowner(inode, NULL);
 150         mutex_unlock(&inode->i_mutex);
 151 }
 152
 153 static struct inode *
 154 rpc_alloc_inode(struct super_block *sb)
 155 {
 156         struct rpc_inode *rpci;
 157         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 158         if (!rpci)
 159                 return NULL;
 160         return &rpci->vfs_inode;
 161 }
 162
 163 static void
 164 rpc_destroy_inode(struct inode *inode)
 165 {
 166         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 167 }
 168
 169 static int
 170 rpc_pipe_open(struct inode *inode, struct file *filp)
 171 {
 172         struct rpc_inode *rpci = RPC_I(inode);
 173         int first_open;
 174         int res = -ENXIO;
 175
 176         mutex_lock(&inode->i_mutex);
 177         if (rpci->ops == NULL)
 178                 goto out;
 179         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
 180         if (first_open && rpci->ops->open_pipe) {
 181                 res = rpci->ops->open_pipe(inode);
 182                 if (res)
 183                         goto out;
 184         }
 185         if (filp->f_mode & FMODE_READ)
 186                 rpci->nreaders++;
 187         if (filp->f_mode & FMODE_WRITE)
 188                 rpci->nwriters++;
 189         res = 0;
 190 out:
 191         mutex_unlock(&inode->i_mutex);
 192         return res;
 193 }
 194
 195 static int
 196 rpc_pipe_release(struct inode *inode, struct file *filp)
 197 {
 198         struct rpc_inode *rpci = RPC_I(inode);
 199         struct rpc_pipe_msg *msg;
 200         int last_close;
 201
 202         mutex_lock(&inode->i_mutex);
 203         if (rpci->ops == NULL)
 204                 goto out;
 205         msg = (struct rpc_pipe_msg *)filp->private_data;
 206         if (msg != NULL) {
 207                 spin_lock(&inode->i_lock);
 208                 msg->errno = -EAGAIN;
 209                 list_del(&msg->list);
 210                 spin_unlock(&inode->i_lock);
 211                 rpci->ops->destroy_msg(msg);
 212         }
 213         if (filp->f_mode & FMODE_WRITE)
 214                 rpci->nwriters --;
 215         if (filp->f_mode & FMODE_READ) {
 216                 rpci->nreaders --;
 217                 if (rpci->nreaders == 0) {
 218                         LIST_HEAD(free_list);
 219                         spin_lock(&inode->i_lock);
 220                         list_splice_init(&rpci->pipe, &free_list);
 221                         rpci->pipelen = 0;
 222                         spin_unlock(&inode->i_lock);
 223                         rpc_purge_list(rpci, &free_list,
 224                                         rpci->ops->destroy_msg, -EAGAIN);
 225                 }
 226         }
 227         last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
 228         if (last_close && rpci->ops->release_pipe)
 229                 rpci->ops->release_pipe(inode);
 230 out:
 231         mutex_unlock(&inode->i_mutex);
 232         return 0;
 233 }
 234
 235 static ssize_t
 236 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 237 {
 238         struct inode *inode = filp->f_path.dentry->d_inode;
 239         struct rpc_inode *rpci = RPC_I(inode);
 240         struct rpc_pipe_msg *msg;
 241         int res = 0;
 242
 243         mutex_lock(&inode->i_mutex);
 244         if (rpci->ops == NULL) {
 245                 res = -EPIPE;
 246                 goto out_unlock;
 247         }
 248         msg = filp->private_data;
 249         if (msg == NULL) {
 250                 spin_lock(&inode->i_lock);
 251                 if (!list_empty(&rpci->pipe)) {
 252                         msg = list_entry(rpci->pipe.next,
 253                                         struct rpc_pipe_msg,
 254                                         list);
 255                         list_move(&msg->list, &rpci->in_upcall);
 256                         rpci->pipelen -= msg->len;
 257                         filp->private_data = msg;
 258                         msg->copied = 0;
 259                 }
 260                 spin_unlock(&inode->i_lock);
 261                 if (msg == NULL)
 262                         goto out_unlock;
 263         }
 264         /* NOTE: it is up to the callback to update msg->copied */
 265         res = rpci->ops->upcall(filp, msg, buf, len);
 266         if (res < 0 || msg->len == msg->copied) {
 267                 filp->private_data = NULL;
 268                 spin_lock(&inode->i_lock);
 269                 list_del(&msg->list);
 270                 spin_unlock(&inode->i_lock);
 271                 rpci->ops->destroy_msg(msg);
 272         }
 273 out_unlock:
 274         mutex_unlock(&inode->i_mutex);
 275         return res;
 276 }
 277
 278 static ssize_t
 279 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 280 {
 281         struct inode *inode = filp->f_path.dentry->d_inode;
 282         struct rpc_inode *rpci = RPC_I(inode);
 283         int res;
 284
 285         mutex_lock(&inode->i_mutex);
 286         res = -EPIPE;
 287         if (rpci->ops != NULL)
 288                 res = rpci->ops->downcall(filp, buf, len);
 289         mutex_unlock(&inode->i_mutex);
 290         return res;
 291 }
 292
 293 static unsigned int
 294 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 295 {
 296         struct rpc_inode *rpci;
 297         unsigned int mask = 0;
 298
 299         rpci = RPC_I(filp->f_path.dentry->d_inode);
 300         poll_wait(filp, &rpci->waitq, wait);
 301
 302         mask = POLLOUT | POLLWRNORM;
 303         if (rpci->ops == NULL)
 304                 mask |= POLLERR | POLLHUP;
 305         if (filp->private_data || !list_empty(&rpci->pipe))
 306                 mask |= POLLIN | POLLRDNORM;
 307         return mask;
 308 }
 309
 310 static int
 311 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 312                 unsigned int cmd, unsigned long arg)
 313 {
 314         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 315         int len;
 316
 317         switch (cmd) {
 318         case FIONREAD:
 319                 if (rpci->ops == NULL)
 320                         return -EPIPE;
 321                 len = rpci->pipelen;
 322                 if (filp->private_data) {
 323                         struct rpc_pipe_msg *msg;
 324                         msg = (struct rpc_pipe_msg *)filp->private_data;
 325                         len += msg->len - msg->copied;
 326                 }
 327                 return put_user(len, (int __user *)arg);
 328         default:
 329                 return -EINVAL;
 330         }
 331 }
 332
 333 static const struct file_operations rpc_pipe_fops = {
 334         .owner          = THIS_MODULE,
 335         .llseek         = no_llseek,
 336         .read           = rpc_pipe_read,
 337         .write          = rpc_pipe_write,
 338         .poll           = rpc_pipe_poll,
 339         .ioctl          = rpc_pipe_ioctl,
 340         .open           = rpc_pipe_open,
 341         .release        = rpc_pipe_release,
 342 };
 343
 344 static int
 345 rpc_show_info(struct seq_file *m, void *v)
 346 {
 347         struct rpc_clnt *clnt = m->private;
 348
 349         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 350         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 351                         clnt->cl_prog, clnt->cl_vers);
 352         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 353         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 354         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 355         return 0;
 356 }
 357
 358 static int
 359 rpc_info_open(struct inode *inode, struct file *file)
 360 {
 361         struct rpc_clnt *clnt;
 362         int ret = single_open(file, rpc_show_info, NULL);
 363
 364         if (!ret) {
 365                 struct seq_file *m = file->private_data;
 366                 mutex_lock(&inode->i_mutex);
 367                 clnt = RPC_I(inode)->private;
 368                 if (clnt) {
 369                         kref_get(&clnt->cl_kref);
 370                         m->private = clnt;
 371                 } else {
 372                         single_release(inode, file);
 373                         ret = -EINVAL;
 374                 }
 375                 mutex_unlock(&inode->i_mutex);
 376         }
 377         return ret;
 378 }
 379
 380 static int
 381 rpc_info_release(struct inode *inode, struct file *file)
 382 {
 383         struct seq_file *m = file->private_data;
 384         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 385
 386         if (clnt)
 387                 rpc_release_client(clnt);
 388         return single_release(inode, file);
 389 }
 390
 391 static const struct file_operations rpc_info_operations = {
 392         .owner          = THIS_MODULE,
 393         .open           = rpc_info_open,
 394         .read           = seq_read,
 395         .llseek         = seq_lseek,
 396         .release        = rpc_info_release,
 397 };
 398
 399
 400 /*
 401  * Description of fs contents.
 402  */
 403 struct rpc_filelist {
 404         const char *name;
 405         const struct file_operations *i_fop;
 406         umode_t mode;
 407 };
 408
 409 struct vfsmount *rpc_get_mount(void)
 410 {
 411         int err;
 412
 413         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 414         if (err != 0)
 415                 return ERR_PTR(err);
 416         return rpc_mount;
 417 }
 418
 419 void rpc_put_mount(void)
 420 {
 421         simple_release_fs(&rpc_mount, &rpc_mount_count);
 422 }
 423
 424 static int rpc_delete_dentry(struct dentry *dentry)
 425 {
 426         return 1;
 427 }
 428
 429 static const struct dentry_operations rpc_dentry_operations = {
 430         .d_delete = rpc_delete_dentry,
 431 };
 432
 433 static struct inode *
 434 rpc_get_inode(struct super_block *sb, umode_t mode)
 435 {
 436         struct inode *inode = new_inode(sb);
 437         if (!inode)
 438                 return NULL;
 439         inode->i_mode = mode;
 440         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 441         switch(mode & S_IFMT) {
 442                 case S_IFDIR:
 443                         inode->i_fop = &simple_dir_operations;
 444                         inode->i_op = &simple_dir_inode_operations;
 445                         inc_nlink(inode);
 446                 default:
 447                         break;
 448         }
 449         return inode;
 450 }
 451
 452 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 453                                umode_t mode,
 454                                const struct file_operations *i_fop,
 455                                void *private)
 456 {
 457         struct inode *inode;
 458
 459         BUG_ON(!d_unhashed(dentry));
 460         inode = rpc_get_inode(dir->i_sb, mode);
 461         if (!inode)
 462                 goto out_err;
 463         inode->i_ino = iunique(dir->i_sb, 100);
 464         if (i_fop)
 465                 inode->i_fop = i_fop;
 466         if (private)
 467                 rpc_inode_setowner(inode, private);
 468         d_add(dentry, inode);
 469         return 0;
 470 out_err:
 471         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 472                         __FILE__, __func__, dentry->d_name.name);
 473         dput(dentry);
 474         return -ENOMEM;
 475 }
 476
 477 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 478                         umode_t mode,
 479                         const struct file_operations *i_fop,
 480                         void *private)
 481 {
 482         int err;
 483
 484         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 485         if (err)
 486                 return err;
 487         fsnotify_create(dir, dentry);
 488         return 0;
 489 }
 490
 491 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 492                        umode_t mode,
 493                        const struct file_operations *i_fop,
 494                        void *private)
 495 {
 496         int err;
 497
 498         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 499         if (err)
 500                 return err;
 501         inc_nlink(dir);
 502         fsnotify_mkdir(dir, dentry);
 503         return 0;
 504 }
 505
 506 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
 507                         umode_t mode,
 508                         const struct file_operations *i_fop,
 509                         void *private,
 510                         const struct rpc_pipe_ops *ops,
 511                         int flags)
 512 {
 513         struct rpc_inode *rpci;
 514         int err;
 515
 516         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 517         if (err)
 518                 return err;
 519         rpci = RPC_I(dentry->d_inode);
 520         rpci->nkern_readwriters = 1;
 521         rpci->private = private;
 522         rpci->flags = flags;
 523         rpci->ops = ops;
 524         fsnotify_create(dir, dentry);
 525         return 0;
 526 }
 527
 528 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 529 {
 530         int ret;
 531
 532         dget(dentry);
 533         ret = simple_rmdir(dir, dentry);
 534         d_delete(dentry);
 535         dput(dentry);
 536         return ret;
 537 }
 538
 539 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 540 {
 541         int ret;
 542
 543         dget(dentry);
 544         ret = simple_unlink(dir, dentry);
 545         d_delete(dentry);
 546         dput(dentry);
 547         return ret;
 548 }
 549
 550 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 551 {
 552         struct inode *inode = dentry->d_inode;
 553         struct rpc_inode *rpci = RPC_I(inode);
 554
 555         rpci->nkern_readwriters--;
 556         if (rpci->nkern_readwriters != 0)
 557                 return 0;
 558         rpc_close_pipes(inode);
 559         return __rpc_unlink(dir, dentry);
 560 }
 561
 562 static struct dentry *__rpc_lookup_create(struct dentry *parent,
 563                                           struct qstr *name)
 564 {
 565         struct dentry *dentry;
 566
 567         dentry = d_lookup(parent, name);
 568         if (!dentry) {
 569                 dentry = d_alloc(parent, name);
 570                 if (!dentry) {
 571                         dentry = ERR_PTR(-ENOMEM);
 572                         goto out_err;
 573                 }
 574         }
 575         if (!dentry->d_inode)
 576                 dentry->d_op = &rpc_dentry_operations;
 577 out_err:
 578         return dentry;
 579 }
 580
 581 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 582                                           struct qstr *name)
 583 {
 584         struct dentry *dentry;
 585
 586         dentry = __rpc_lookup_create(parent, name);
 587         if (dentry->d_inode == NULL)
 588                 return dentry;
 589         dput(dentry);
 590         return ERR_PTR(-EEXIST);
 591 }
 592
 593 /*
 594  * FIXME: This probably has races.
 595  */
 596 static void __rpc_depopulate(struct dentry *parent,
 597                              const struct rpc_filelist *files,
 598                              int start, int eof)
 599 {
 600         struct inode *dir = parent->d_inode;
 601         struct dentry *dentry;
 602         struct qstr name;
 603         int i;
 604
 605         for (i = start; i < eof; i++) {
 606                 name.name = files[i].name;
 607                 name.len = strlen(files[i].name);
 608                 name.hash = full_name_hash(name.name, name.len);
 609                 dentry = d_lookup(parent, &name);
 610
 611                 if (dentry == NULL)
 612                         continue;
 613                 if (dentry->d_inode == NULL)
 614                         goto next;
 615                 switch (dentry->d_inode->i_mode & S_IFMT) {
 616                         default:
 617                                 BUG();
 618                         case S_IFREG:
 619                                 __rpc_unlink(dir, dentry);
 620                                 break;
 621                         case S_IFDIR:
 622                                 __rpc_rmdir(dir, dentry);
 623                 }
 624 next:
 625                 dput(dentry);
 626         }
 627 }
 628
 629 static void rpc_depopulate(struct dentry *parent,
 630                            const struct rpc_filelist *files,
 631                            int start, int eof)
 632 {
 633         struct inode *dir = parent->d_inode;
 634
 635         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 636         __rpc_depopulate(parent, files, start, eof);
 637         mutex_unlock(&dir->i_mutex);
 638 }
 639
 640 static int rpc_populate(struct dentry *parent,
 641                         const struct rpc_filelist *files,
 642                         int start, int eof,
 643                         void *private)
 644 {
 645         struct inode *dir = parent->d_inode;
 646         struct dentry *dentry;
 647         int i, err;
 648
 649         mutex_lock(&dir->i_mutex);
 650         for (i = start; i < eof; i++) {
 651                 struct qstr q;
 652
 653                 q.name = files[i].name;
 654                 q.len = strlen(files[i].name);
 655                 q.hash = full_name_hash(q.name, q.len);
 656                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 657                 err = PTR_ERR(dentry);
 658                 if (IS_ERR(dentry))
 659                         goto out_bad;
 660                 switch (files[i].mode & S_IFMT) {
 661                         default:
 662                                 BUG();
 663                         case S_IFREG:
 664                                 err = __rpc_create(dir, dentry,
 665                                                 files[i].mode,
 666                                                 files[i].i_fop,
 667                                                 private);
 668                                 break;
 669                         case S_IFDIR:
 670                                 err = __rpc_mkdir(dir, dentry,
 671                                                 files[i].mode,
 672                                                 NULL,
 673                                                 private);
 674                 }
 675                 if (err != 0)
 676                         goto out_bad;
 677         }
 678         mutex_unlock(&dir->i_mutex);
 679         return 0;
 680 out_bad:
 681         __rpc_depopulate(parent, files, start, eof);
 682         mutex_unlock(&dir->i_mutex);
 683         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 684                         __FILE__, __func__, parent->d_name.name);
 685         return err;
 686 }
 687
 688 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 689                 struct qstr *name, umode_t mode, void *private,
 690                 int (*populate)(struct dentry *, void *), void *args_populate)
 691 {
 692         struct dentry *dentry;
 693         struct inode *dir = parent->d_inode;
 694         int error;
 695
 696         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 697         dentry = __rpc_lookup_create_exclusive(parent, name);
 698         if (IS_ERR(dentry))
 699                 goto out;
 700         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 701         if (error != 0)
 702                 goto out_err;
 703         if (populate != NULL) {
 704                 error = populate(dentry, args_populate);
 705                 if (error)
 706                         goto err_rmdir;
 707         }
 708 out:
 709         mutex_unlock(&dir->i_mutex);
 710         return dentry;
 711 err_rmdir:
 712         __rpc_rmdir(dir, dentry);
 713 out_err:
 714         dentry = ERR_PTR(error);
 715         goto out;
 716 }
 717
 718 static int rpc_rmdir_depopulate(struct dentry *dentry,
 719                 void (*depopulate)(struct dentry *))
 720 {
 721         struct dentry *parent;
 722         struct inode *dir;
 723         int error;
 724
 725         parent = dget_parent(dentry);
 726         dir = parent->d_inode;
 727         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 728         if (depopulate != NULL)
 729                 depopulate(dentry);
 730         error = __rpc_rmdir(dir, dentry);
 731         mutex_unlock(&dir->i_mutex);
 732         dput(parent);
 733         return error;
 734 }
 735
 736 /**
 737  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 738  * @parent: dentry of directory to create new "pipe" in
 739  * @name: name of pipe
 740  * @private: private data to associate with the pipe, for the caller's use
 741  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 742  *      release_pipe, open_pipe, and destroy_msg.
 743  * @flags: rpc_inode flags
 744  *
 745  * Data is made available for userspace to read by calls to
 746  * rpc_queue_upcall().  The actual reads will result in calls to
 747  * @ops->upcall, which will be called with the file pointer,
 748  * message, and userspace buffer to copy to.
 749  *
 750  * Writes can come at any time, and do not necessarily have to be
 751  * responses to upcalls.  They will result in calls to @msg->downcall.
 752  *
 753  * The @private argument passed here will be available to all these methods
 754  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 755  */
 756 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 757                           void *private, const struct rpc_pipe_ops *ops,
 758                           int flags)
 759 {
 760         struct dentry *dentry;
 761         struct inode *dir = parent->d_inode;
 762         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 763         struct qstr q;
 764         int err;
 765
 766         if (ops->upcall == NULL)
 767                 umode &= ~S_IRUGO;
 768         if (ops->downcall == NULL)
 769                 umode &= ~S_IWUGO;
 770
 771         q.name = name;
 772         q.len = strlen(name);
 773         q.hash = full_name_hash(q.name, q.len),
 774
 775         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 776         dentry = __rpc_lookup_create(parent, &q);
 777         if (IS_ERR(dentry))
 778                 goto out;
 779         if (dentry->d_inode) {
 780                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 781                 if (rpci->private != private ||
 782                                 rpci->ops != ops ||
 783                                 rpci->flags != flags) {
 784                         dput (dentry);
 785                         err = -EBUSY;
 786                         goto out_err;
 787                 }
 788                 rpci->nkern_readwriters++;
 789                 goto out;
 790         }
 791
 792         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 793                            private, ops, flags);
 794         if (err)
 795                 goto out_err;
 796 out:
 797         mutex_unlock(&dir->i_mutex);
 798         return dentry;
 799 out_err:
 800         dentry = ERR_PTR(err);
 801         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 802                         __FILE__, __func__, parent->d_name.name, name,
 803                         err);
 804         goto out;
 805 }
 806 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 807
 808 /**
 809  * rpc_unlink - remove a pipe
 810  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 811  *
 812  * After this call, lookups will no longer find the pipe, and any
 813  * attempts to read or write using preexisting opens of the pipe will
 814  * return -EPIPE.
 815  */
 816 int
 817 rpc_unlink(struct dentry *dentry)
 818 {
 819         struct dentry *parent;
 820         struct inode *dir;
 821         int error = 0;
 822
 823         parent = dget_parent(dentry);
 824         dir = parent->d_inode;
 825         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 826         error = __rpc_rmpipe(dir, dentry);
 827         mutex_unlock(&dir->i_mutex);
 828         dput(parent);
 829         return error;
 830 }
 831 EXPORT_SYMBOL_GPL(rpc_unlink);
 832
 833 enum {
 834         RPCAUTH_info,
 835         RPCAUTH_EOF
 836 };
 837
 838 static const struct rpc_filelist authfiles[] = {
 839         [RPCAUTH_info] = {
 840                 .name = "info",
 841                 .i_fop = &rpc_info_operations,
 842                 .mode = S_IFREG | S_IRUSR,
 843         },
 844 };
 845
 846 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 847 {
 848         return rpc_populate(dentry,
 849                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 850                             private);
 851 }
 852
 853 static void rpc_clntdir_depopulate(struct dentry *dentry)
 854 {
 855         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 856 }
 857
 858 /**
 859  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 860  * @path: path from the rpc_pipefs root to the new directory
 861  * @rpc_client: rpc client to associate with this directory
 862  *
 863  * This creates a directory at the given @path associated with
 864  * @rpc_clnt, which will contain a file named "info" with some basic
 865  * information about the client, together with any "pipes" that may
 866  * later be created using rpc_mkpipe().
 867  */
 868 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 869                                    struct qstr *name,
 870                                    struct rpc_clnt *rpc_client)
 871 {
 872         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 873                         rpc_clntdir_populate, rpc_client);
 874 }
 875
 876 /**
 877  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 878  * @dentry: directory to remove
 879  */
 880 int rpc_remove_client_dir(struct dentry *dentry)
 881 {
 882         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 883 }
 884
 885 /*
 886  * populate the filesystem
 887  */
 888 static struct super_operations s_ops = {
 889         .alloc_inode    = rpc_alloc_inode,
 890         .destroy_inode  = rpc_destroy_inode,
 891         .statfs         = simple_statfs,
 892 };
 893
 894 #define RPCAUTH_GSSMAGIC 0x67596969
 895
 896 /*
 897  * We have a single directory with 1 node in it.
 898  */
 899 enum {
 900         RPCAUTH_lockd,
 901         RPCAUTH_mount,
 902         RPCAUTH_nfs,
 903         RPCAUTH_portmap,
 904         RPCAUTH_statd,
 905         RPCAUTH_nfsd4_cb,
 906         RPCAUTH_RootEOF
 907 };
 908
 909 static const struct rpc_filelist files[] = {
 910         [RPCAUTH_lockd] = {
 911                 .name = "lockd",
 912                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 913         },
 914         [RPCAUTH_mount] = {
 915                 .name = "mount",
 916                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 917         },
 918         [RPCAUTH_nfs] = {
 919                 .name = "nfs",
 920                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 921         },
 922         [RPCAUTH_portmap] = {
 923                 .name = "portmap",
 924                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 925         },
 926         [RPCAUTH_statd] = {
 927                 .name = "statd",
 928                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 929         },
 930         [RPCAUTH_nfsd4_cb] = {
 931                 .name = "nfsd4_cb",
 932                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 933         },
 934 };
 935
 936 static int
 937 rpc_fill_super(struct super_block *sb, void *data, int silent)
 938 {
 939         struct inode *inode;
 940         struct dentry *root;
 941
 942         sb->s_blocksize = PAGE_CACHE_SIZE;
 943         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 944         sb->s_magic = RPCAUTH_GSSMAGIC;
 945         sb->s_op = &s_ops;
 946         sb->s_time_gran = 1;
 947
 948         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 949         if (!inode)
 950                 return -ENOMEM;
 951         root = d_alloc_root(inode);
 952         if (!root) {
 953                 iput(inode);
 954                 return -ENOMEM;
 955         }
 956         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
 957                 goto out;
 958         sb->s_root = root;
 959         return 0;
 960 out:
 961         d_genocide(root);
 962         dput(root);
 963         return -ENOMEM;
 964 }
 965
 966 static int
 967 rpc_get_sb(struct file_system_type *fs_type,
 968                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 969 {
 970         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
 971 }
 972
 973 static struct file_system_type rpc_pipe_fs_type = {
 974         .owner          = THIS_MODULE,
 975         .name           = "rpc_pipefs",
 976         .get_sb         = rpc_get_sb,
 977         .kill_sb        = kill_litter_super,
 978 };
 979
 980 static void
 981 init_once(void *foo)
 982 {
 983         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 984
 985         inode_init_once(&rpci->vfs_inode);
 986         rpci->private = NULL;
 987         rpci->nreaders = 0;
 988         rpci->nwriters = 0;
 989         INIT_LIST_HEAD(&rpci->in_upcall);
 990         INIT_LIST_HEAD(&rpci->in_downcall);
 991         INIT_LIST_HEAD(&rpci->pipe);
 992         rpci->pipelen = 0;
 993         init_waitqueue_head(&rpci->waitq);
 994         INIT_DELAYED_WORK(&rpci->queue_timeout,
 995                             rpc_timeout_upcall_queue);
 996         rpci->ops = NULL;
 997 }
 998
 999 int register_rpc_pipefs(void)
1000 {
1001         int err;
1002
1003         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1004                                 sizeof(struct rpc_inode),
1005                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1006                                                 SLAB_MEM_SPREAD),
1007                                 init_once);
1008         if (!rpc_inode_cachep)
1009                 return -ENOMEM;
1010         err = register_filesystem(&rpc_pipe_fs_type);
1011         if (err) {
1012                 kmem_cache_destroy(rpc_inode_cachep);
1013                 return err;
1014         }
1015
1016         return 0;
1017 }
1018
1019 void unregister_rpc_pipefs(void)
1020 {
1021         kmem_cache_destroy(rpc_inode_cachep);
1022         unregister_filesystem(&rpc_pipe_fs_type);
1023 }