fs/sysfs/bin.c

   1 /*
   2  * fs/sysfs/bin.c - sysfs binary file implementation
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Matthew Wilcox
   6  * Copyright (c) 2004 Silicon Graphics, Inc.
   7  * Copyright (c) 2007 SUSE Linux Products GmbH
   8  * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
   9  *
  10  * This file is released under the GPLv2.
  11  *
  12  * Please see Documentation/filesystems/sysfs.txt for more information.
  13  */
  14
  15 #undef DEBUG
  16
  17 #include <linux/errno.h>
  18 #include <linux/fs.h>
  19 #include <linux/kernel.h>
  20 #include <linux/kobject.h>
  21 #include <linux/module.h>
  22 #include <linux/slab.h>
  23 #include <linux/mutex.h>
  24 #include <linux/mm.h>
  25
  26 #include <asm/uaccess.h>
  27
  28 #include "sysfs.h"
  29
  30 /*
  31  * There's one bin_buffer for each open file.
  32  *
  33  * filp->private_data points to bin_buffer and
  34  * sysfs_dirent->s_bin_attr.buffers points to a the bin_buffer s
  35  * sysfs_dirent->s_bin_attr.buffers is protected by sysfs_bin_lock
  36  */
  37 static DEFINE_MUTEX(sysfs_bin_lock);
  38
  39 struct bin_buffer {
  40         struct mutex                    mutex;
  41         void                            *buffer;
  42         int                             mmapped;
  43         struct vm_operations_struct     *vm_ops;
  44         struct file                     *file;
  45         struct hlist_node               list;
  46 };
  47
  48 static int
  49 fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count)
  50 {
  51         struct sysfs_dirent *attr_sd = dentry->d_fsdata;
  52         struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
  53         struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
  54         int rc;
  55
  56         /* need attr_sd for attr, its parent for kobj */
  57         if (!sysfs_get_active_two(attr_sd))
  58                 return -ENODEV;
  59
  60         rc = -EIO;
  61         if (attr->read)
  62                 rc = attr->read(kobj, attr, buffer, off, count);
  63
  64         sysfs_put_active_two(attr_sd);
  65
  66         return rc;
  67 }
  68
  69 static ssize_t
  70 read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off)
  71 {
  72         struct bin_buffer *bb = file->private_data;
  73         struct dentry *dentry = file->f_path.dentry;
  74         int size = dentry->d_inode->i_size;
  75         loff_t offs = *off;
  76         int count = min_t(size_t, bytes, PAGE_SIZE);
  77         char *temp;
  78
  79         if (!bytes)
  80                 return 0;
  81
  82         if (size) {
  83                 if (offs > size)
  84                         return 0;
  85                 if (offs + count > size)
  86                         count = size - offs;
  87         }
  88
  89         temp = kmalloc(count, GFP_KERNEL);
  90         if (!temp)
  91                 return -ENOMEM;
  92
  93         mutex_lock(&bb->mutex);
  94
  95         count = fill_read(dentry, bb->buffer, offs, count);
  96         if (count < 0) {
  97                 mutex_unlock(&bb->mutex);
  98                 goto out_free;
  99         }
 100
 101         memcpy(temp, bb->buffer, count);
 102
 103         mutex_unlock(&bb->mutex);
 104
 105         if (copy_to_user(userbuf, temp, count)) {
 106                 count = -EFAULT;
 107                 goto out_free;
 108         }
 109
 110         pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);
 111
 112         *off = offs + count;
 113
 114  out_free:
 115         kfree(temp);
 116         return count;
 117 }
 118
 119 static int
 120 flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count)
 121 {
 122         struct sysfs_dirent *attr_sd = dentry->d_fsdata;
 123         struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
 124         struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
 125         int rc;
 126
 127         /* need attr_sd for attr, its parent for kobj */
 128         if (!sysfs_get_active_two(attr_sd))
 129                 return -ENODEV;
 130
 131         rc = -EIO;
 132         if (attr->write)
 133                 rc = attr->write(kobj, attr, buffer, offset, count);
 134
 135         sysfs_put_active_two(attr_sd);
 136
 137         return rc;
 138 }
 139
 140 static ssize_t write(struct file *file, const char __user *userbuf,
 141                      size_t bytes, loff_t *off)
 142 {
 143         struct bin_buffer *bb = file->private_data;
 144         struct dentry *dentry = file->f_path.dentry;
 145         int size = dentry->d_inode->i_size;
 146         loff_t offs = *off;
 147         int count = min_t(size_t, bytes, PAGE_SIZE);
 148         char *temp;
 149
 150         if (!bytes)
 151                 return 0;
 152
 153         if (size) {
 154                 if (offs > size)
 155                         return 0;
 156                 if (offs + count > size)
 157                         count = size - offs;
 158         }
 159
 160         temp = kmalloc(count, GFP_KERNEL);
 161         if (!temp)
 162                 return -ENOMEM;
 163
 164         if (copy_from_user(temp, userbuf, count)) {
 165                 count = -EFAULT;
 166                 goto out_free;
 167         }
 168
 169         mutex_lock(&bb->mutex);
 170
 171         memcpy(bb->buffer, temp, count);
 172
 173         count = flush_write(dentry, bb->buffer, offs, count);
 174         mutex_unlock(&bb->mutex);
 175
 176         if (count > 0)
 177                 *off = offs + count;
 178
 179 out_free:
 180         kfree(temp);
 181         return count;
 182 }
 183
 184 static void bin_vma_open(struct vm_area_struct *vma)
 185 {
 186         struct file *file = vma->vm_file;
 187         struct bin_buffer *bb = file->private_data;
 188         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 189
 190         if (!bb->vm_ops || !bb->vm_ops->open)
 191                 return;
 192
 193         if (!sysfs_get_active_two(attr_sd))
 194                 return;
 195
 196         bb->vm_ops->open(vma);
 197
 198         sysfs_put_active_two(attr_sd);
 199 }
 200
 201 static void bin_vma_close(struct vm_area_struct *vma)
 202 {
 203         struct file *file = vma->vm_file;
 204         struct bin_buffer *bb = file->private_data;
 205         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 206
 207         if (!bb->vm_ops || !bb->vm_ops->close)
 208                 return;
 209
 210         if (!sysfs_get_active_two(attr_sd))
 211                 return;
 212
 213         bb->vm_ops->close(vma);
 214
 215         sysfs_put_active_two(attr_sd);
 216 }
 217
 218 static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 219 {
 220         struct file *file = vma->vm_file;
 221         struct bin_buffer *bb = file->private_data;
 222         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 223         int ret;
 224
 225         if (!bb->vm_ops || !bb->vm_ops->fault)
 226                 return VM_FAULT_SIGBUS;
 227
 228         if (!sysfs_get_active_two(attr_sd))
 229                 return VM_FAULT_SIGBUS;
 230
 231         ret = bb->vm_ops->fault(vma, vmf);
 232
 233         sysfs_put_active_two(attr_sd);
 234         return ret;
 235 }
 236
 237 static int bin_page_mkwrite(struct vm_area_struct *vma, struct page *page)
 238 {
 239         struct file *file = vma->vm_file;
 240         struct bin_buffer *bb = file->private_data;
 241         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 242         int ret;
 243
 244         if (!bb->vm_ops)
 245                 return -EINVAL;
 246
 247         if (!bb->vm_ops->page_mkwrite)
 248                 return 0;
 249
 250         if (!sysfs_get_active_two(attr_sd))
 251                 return -EINVAL;
 252
 253         ret = bb->vm_ops->page_mkwrite(vma, page);
 254
 255         sysfs_put_active_two(attr_sd);
 256         return ret;
 257 }
 258
 259 static int bin_access(struct vm_area_struct *vma, unsigned long addr,
 260                   void *buf, int len, int write)
 261 {
 262         struct file *file = vma->vm_file;
 263         struct bin_buffer *bb = file->private_data;
 264         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 265         int ret;
 266
 267         if (!bb->vm_ops || !bb->vm_ops->access)
 268                 return -EINVAL;
 269
 270         if (!sysfs_get_active_two(attr_sd))
 271                 return -EINVAL;
 272
 273         ret = bb->vm_ops->access(vma, addr, buf, len, write);
 274
 275         sysfs_put_active_two(attr_sd);
 276         return ret;
 277 }
 278
 279 #ifdef CONFIG_NUMA
 280 static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 281 {
 282         struct file *file = vma->vm_file;
 283         struct bin_buffer *bb = file->private_data;
 284         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 285         int ret;
 286
 287         if (!bb->vm_ops || !bb->vm_ops->set_policy)
 288                 return 0;
 289
 290         if (!sysfs_get_active_two(attr_sd))
 291                 return -EINVAL;
 292
 293         ret = bb->vm_ops->set_policy(vma, new);
 294
 295         sysfs_put_active_two(attr_sd);
 296         return ret;
 297 }
 298
 299 static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
 300                                         unsigned long addr)
 301 {
 302         struct file *file = vma->vm_file;
 303         struct bin_buffer *bb = file->private_data;
 304         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 305         struct mempolicy *pol;
 306
 307         if (!bb->vm_ops || !bb->vm_ops->get_policy)
 308                 return vma->vm_policy;
 309
 310         if (!sysfs_get_active_two(attr_sd))
 311                 return vma->vm_policy;
 312
 313         pol = bb->vm_ops->get_policy(vma, addr);
 314
 315         sysfs_put_active_two(attr_sd);
 316         return pol;
 317 }
 318
 319 static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
 320                         const nodemask_t *to, unsigned long flags)
 321 {
 322         struct file *file = vma->vm_file;
 323         struct bin_buffer *bb = file->private_data;
 324         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 325         int ret;
 326
 327         if (!bb->vm_ops || !bb->vm_ops->migrate)
 328                 return 0;
 329
 330         if (!sysfs_get_active_two(attr_sd))
 331                 return 0;
 332
 333         ret = bb->vm_ops->migrate(vma, from, to, flags);
 334
 335         sysfs_put_active_two(attr_sd);
 336         return ret;
 337 }
 338 #endif
 339
 340 static struct vm_operations_struct bin_vm_ops = {
 341         .open           = bin_vma_open,
 342         .close          = bin_vma_close,
 343         .fault          = bin_fault,
 344         .page_mkwrite   = bin_page_mkwrite,
 345         .access         = bin_access,
 346 #ifdef CONFIG_NUMA
 347         .set_policy     = bin_set_policy,
 348         .get_policy     = bin_get_policy,
 349         .migrate        = bin_migrate,
 350 #endif
 351 };
 352
 353 static int mmap(struct file *file, struct vm_area_struct *vma)
 354 {
 355         struct bin_buffer *bb = file->private_data;
 356         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 357         struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
 358         struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
 359         int rc;
 360
 361         mutex_lock(&bb->mutex);
 362
 363         /* need attr_sd for attr, its parent for kobj */
 364         rc = -ENODEV;
 365         if (!sysfs_get_active_two(attr_sd))
 366                 goto out_unlock;
 367
 368         rc = -EINVAL;
 369         if (!attr->mmap)
 370                 goto out_put;
 371
 372         rc = attr->mmap(kobj, attr, vma);
 373         if (rc)
 374                 goto out_put;
 375
 376         /*
 377          * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
 378          * to satisfy versions of X which crash if the mmap fails: that
 379          * substitutes a new vm_file, and we don't then want bin_vm_ops.
 380          */
 381         if (vma->vm_file != file)
 382                 goto out_put;
 383
 384         rc = -EINVAL;
 385         if (bb->mmapped && bb->vm_ops != vma->vm_ops)
 386                 goto out_put;
 387
 388         rc = 0;
 389         bb->mmapped = 1;
 390         bb->vm_ops = vma->vm_ops;
 391         vma->vm_ops = &bin_vm_ops;
 392 out_put:
 393         sysfs_put_active_two(attr_sd);
 394 out_unlock:
 395         mutex_unlock(&bb->mutex);
 396
 397         return rc;
 398 }
 399
 400 static int open(struct inode * inode, struct file * file)
 401 {
 402         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 403         struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
 404         struct bin_buffer *bb = NULL;
 405         int error;
 406
 407         /* binary file operations requires both @sd and its parent */
 408         if (!sysfs_get_active_two(attr_sd))
 409                 return -ENODEV;
 410
 411         error = -EACCES;
 412         if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
 413                 goto err_out;
 414         if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
 415                 goto err_out;
 416
 417         error = -ENOMEM;
 418         bb = kzalloc(sizeof(*bb), GFP_KERNEL);
 419         if (!bb)
 420                 goto err_out;
 421
 422         bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
 423         if (!bb->buffer)
 424                 goto err_out;
 425
 426         mutex_init(&bb->mutex);
 427         bb->file = file;
 428         file->private_data = bb;
 429
 430         mutex_lock(&sysfs_bin_lock);
 431         hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers);
 432         mutex_unlock(&sysfs_bin_lock);
 433
 434         /* open succeeded, put active references */
 435         sysfs_put_active_two(attr_sd);
 436         return 0;
 437
 438  err_out:
 439         sysfs_put_active_two(attr_sd);
 440         kfree(bb);
 441         return error;
 442 }
 443
 444 static int release(struct inode * inode, struct file * file)
 445 {
 446         struct bin_buffer *bb = file->private_data;
 447
 448         mutex_lock(&sysfs_bin_lock);
 449         hlist_del(&bb->list);
 450         mutex_unlock(&sysfs_bin_lock);
 451
 452         kfree(bb->buffer);
 453         kfree(bb);
 454         return 0;
 455 }
 456
 457 const struct file_operations bin_fops = {
 458         .read           = read,
 459         .write          = write,
 460         .mmap           = mmap,
 461         .llseek         = generic_file_llseek,
 462         .open           = open,
 463         .release        = release,
 464 };
 465
 466
 467 void unmap_bin_file(struct sysfs_dirent *attr_sd)
 468 {
 469         struct bin_buffer *bb;
 470         struct hlist_node *tmp;
 471
 472         if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR)
 473                 return;
 474
 475         mutex_lock(&sysfs_bin_lock);
 476
 477         hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) {
 478                 struct inode *inode = bb->file->f_path.dentry->d_inode;
 479
 480                 unmap_mapping_range(inode->i_mapping, 0, 0, 1);
 481         }
 482
 483         mutex_unlock(&sysfs_bin_lock);
 484 }
 485
 486 /**
 487  *      sysfs_create_bin_file - create binary file for object.
 488  *      @kobj:  object.
 489  *      @attr:  attribute descriptor.
 490  */
 491
 492 int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 493 {
 494         BUG_ON(!kobj || !kobj->sd || !attr);
 495
 496         return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
 497 }
 498
 499
 500 /**
 501  *      sysfs_remove_bin_file - remove binary file for object.
 502  *      @kobj:  object.
 503  *      @attr:  attribute descriptor.
 504  */
 505
 506 void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 507 {
 508         sysfs_hash_and_remove(kobj->sd, attr->attr.name);
 509 }
 510
 511 EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
 512 EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);