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 = memdup_user(userbuf, count);
 161         if (IS_ERR(temp))
 162                 return PTR_ERR(temp);
 163
 164         mutex_lock(&bb->mutex);
 165
 166         memcpy(bb->buffer, temp, count);
 167
 168         count = flush_write(dentry, bb->buffer, offs, count);
 169         mutex_unlock(&bb->mutex);
 170
 171         if (count > 0)
 172                 *off = offs + count;
 173
 174         return count;
 175 }
 176
 177 static void bin_vma_open(struct vm_area_struct *vma)
 178 {
 179         struct file *file = vma->vm_file;
 180         struct bin_buffer *bb = file->private_data;
 181         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 182
 183         if (!bb->vm_ops || !bb->vm_ops->open)
 184                 return;
 185
 186         if (!sysfs_get_active_two(attr_sd))
 187                 return;
 188
 189         bb->vm_ops->open(vma);
 190
 191         sysfs_put_active_two(attr_sd);
 192 }
 193
 194 static void bin_vma_close(struct vm_area_struct *vma)
 195 {
 196         struct file *file = vma->vm_file;
 197         struct bin_buffer *bb = file->private_data;
 198         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 199
 200         if (!bb->vm_ops || !bb->vm_ops->close)
 201                 return;
 202
 203         if (!sysfs_get_active_two(attr_sd))
 204                 return;
 205
 206         bb->vm_ops->close(vma);
 207
 208         sysfs_put_active_two(attr_sd);
 209 }
 210
 211 static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 212 {
 213         struct file *file = vma->vm_file;
 214         struct bin_buffer *bb = file->private_data;
 215         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 216         int ret;
 217
 218         if (!bb->vm_ops || !bb->vm_ops->fault)
 219                 return VM_FAULT_SIGBUS;
 220
 221         if (!sysfs_get_active_two(attr_sd))
 222                 return VM_FAULT_SIGBUS;
 223
 224         ret = bb->vm_ops->fault(vma, vmf);
 225
 226         sysfs_put_active_two(attr_sd);
 227         return ret;
 228 }
 229
 230 static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 231 {
 232         struct file *file = vma->vm_file;
 233         struct bin_buffer *bb = file->private_data;
 234         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 235         int ret;
 236
 237         if (!bb->vm_ops)
 238                 return VM_FAULT_SIGBUS;
 239
 240         if (!bb->vm_ops->page_mkwrite)
 241                 return 0;
 242
 243         if (!sysfs_get_active_two(attr_sd))
 244                 return VM_FAULT_SIGBUS;
 245
 246         ret = bb->vm_ops->page_mkwrite(vma, vmf);
 247
 248         sysfs_put_active_two(attr_sd);
 249         return ret;
 250 }
 251
 252 static int bin_access(struct vm_area_struct *vma, unsigned long addr,
 253                   void *buf, int len, int write)
 254 {
 255         struct file *file = vma->vm_file;
 256         struct bin_buffer *bb = file->private_data;
 257         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 258         int ret;
 259
 260         if (!bb->vm_ops || !bb->vm_ops->access)
 261                 return -EINVAL;
 262
 263         if (!sysfs_get_active_two(attr_sd))
 264                 return -EINVAL;
 265
 266         ret = bb->vm_ops->access(vma, addr, buf, len, write);
 267
 268         sysfs_put_active_two(attr_sd);
 269         return ret;
 270 }
 271
 272 #ifdef CONFIG_NUMA
 273 static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 274 {
 275         struct file *file = vma->vm_file;
 276         struct bin_buffer *bb = file->private_data;
 277         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 278         int ret;
 279
 280         if (!bb->vm_ops || !bb->vm_ops->set_policy)
 281                 return 0;
 282
 283         if (!sysfs_get_active_two(attr_sd))
 284                 return -EINVAL;
 285
 286         ret = bb->vm_ops->set_policy(vma, new);
 287
 288         sysfs_put_active_two(attr_sd);
 289         return ret;
 290 }
 291
 292 static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
 293                                         unsigned long addr)
 294 {
 295         struct file *file = vma->vm_file;
 296         struct bin_buffer *bb = file->private_data;
 297         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 298         struct mempolicy *pol;
 299
 300         if (!bb->vm_ops || !bb->vm_ops->get_policy)
 301                 return vma->vm_policy;
 302
 303         if (!sysfs_get_active_two(attr_sd))
 304                 return vma->vm_policy;
 305
 306         pol = bb->vm_ops->get_policy(vma, addr);
 307
 308         sysfs_put_active_two(attr_sd);
 309         return pol;
 310 }
 311
 312 static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
 313                         const nodemask_t *to, unsigned long flags)
 314 {
 315         struct file *file = vma->vm_file;
 316         struct bin_buffer *bb = file->private_data;
 317         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 318         int ret;
 319
 320         if (!bb->vm_ops || !bb->vm_ops->migrate)
 321                 return 0;
 322
 323         if (!sysfs_get_active_two(attr_sd))
 324                 return 0;
 325
 326         ret = bb->vm_ops->migrate(vma, from, to, flags);
 327
 328         sysfs_put_active_two(attr_sd);
 329         return ret;
 330 }
 331 #endif
 332
 333 static struct vm_operations_struct bin_vm_ops = {
 334         .open           = bin_vma_open,
 335         .close          = bin_vma_close,
 336         .fault          = bin_fault,
 337         .page_mkwrite   = bin_page_mkwrite,
 338         .access         = bin_access,
 339 #ifdef CONFIG_NUMA
 340         .set_policy     = bin_set_policy,
 341         .get_policy     = bin_get_policy,
 342         .migrate        = bin_migrate,
 343 #endif
 344 };
 345
 346 static int mmap(struct file *file, struct vm_area_struct *vma)
 347 {
 348         struct bin_buffer *bb = file->private_data;
 349         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 350         struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
 351         struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
 352         int rc;
 353
 354         mutex_lock(&bb->mutex);
 355
 356         /* need attr_sd for attr, its parent for kobj */
 357         rc = -ENODEV;
 358         if (!sysfs_get_active_two(attr_sd))
 359                 goto out_unlock;
 360
 361         rc = -EINVAL;
 362         if (!attr->mmap)
 363                 goto out_put;
 364
 365         rc = attr->mmap(kobj, attr, vma);
 366         if (rc)
 367                 goto out_put;
 368
 369         /*
 370          * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
 371          * to satisfy versions of X which crash if the mmap fails: that
 372          * substitutes a new vm_file, and we don't then want bin_vm_ops.
 373          */
 374         if (vma->vm_file != file)
 375                 goto out_put;
 376
 377         rc = -EINVAL;
 378         if (bb->mmapped && bb->vm_ops != vma->vm_ops)
 379                 goto out_put;
 380
 381         rc = 0;
 382         bb->mmapped = 1;
 383         bb->vm_ops = vma->vm_ops;
 384         vma->vm_ops = &bin_vm_ops;
 385 out_put:
 386         sysfs_put_active_two(attr_sd);
 387 out_unlock:
 388         mutex_unlock(&bb->mutex);
 389
 390         return rc;
 391 }
 392
 393 static int open(struct inode * inode, struct file * file)
 394 {
 395         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
 396         struct bin_attribute *attr = attr_sd->s_bin_attr.bin_attr;
 397         struct bin_buffer *bb = NULL;
 398         int error;
 399
 400         /* binary file operations requires both @sd and its parent */
 401         if (!sysfs_get_active_two(attr_sd))
 402                 return -ENODEV;
 403
 404         error = -EACCES;
 405         if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
 406                 goto err_out;
 407         if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
 408                 goto err_out;
 409
 410         error = -ENOMEM;
 411         bb = kzalloc(sizeof(*bb), GFP_KERNEL);
 412         if (!bb)
 413                 goto err_out;
 414
 415         bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
 416         if (!bb->buffer)
 417                 goto err_out;
 418
 419         mutex_init(&bb->mutex);
 420         bb->file = file;
 421         file->private_data = bb;
 422
 423         mutex_lock(&sysfs_bin_lock);
 424         hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers);
 425         mutex_unlock(&sysfs_bin_lock);
 426
 427         /* open succeeded, put active references */
 428         sysfs_put_active_two(attr_sd);
 429         return 0;
 430
 431  err_out:
 432         sysfs_put_active_two(attr_sd);
 433         kfree(bb);
 434         return error;
 435 }
 436
 437 static int release(struct inode * inode, struct file * file)
 438 {
 439         struct bin_buffer *bb = file->private_data;
 440
 441         mutex_lock(&sysfs_bin_lock);
 442         hlist_del(&bb->list);
 443         mutex_unlock(&sysfs_bin_lock);
 444
 445         kfree(bb->buffer);
 446         kfree(bb);
 447         return 0;
 448 }
 449
 450 const struct file_operations bin_fops = {
 451         .read           = read,
 452         .write          = write,
 453         .mmap           = mmap,
 454         .llseek         = generic_file_llseek,
 455         .open           = open,
 456         .release        = release,
 457 };
 458
 459
 460 void unmap_bin_file(struct sysfs_dirent *attr_sd)
 461 {
 462         struct bin_buffer *bb;
 463         struct hlist_node *tmp;
 464
 465         if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR)
 466                 return;
 467
 468         mutex_lock(&sysfs_bin_lock);
 469
 470         hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) {
 471                 struct inode *inode = bb->file->f_path.dentry->d_inode;
 472
 473                 unmap_mapping_range(inode->i_mapping, 0, 0, 1);
 474         }
 475
 476         mutex_unlock(&sysfs_bin_lock);
 477 }
 478
 479 /**
 480  *      sysfs_create_bin_file - create binary file for object.
 481  *      @kobj:  object.
 482  *      @attr:  attribute descriptor.
 483  */
 484
 485 int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 486 {
 487         BUG_ON(!kobj || !kobj->sd || !attr);
 488
 489         return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
 490 }
 491
 492
 493 /**
 494  *      sysfs_remove_bin_file - remove binary file for object.
 495  *      @kobj:  object.
 496  *      @attr:  attribute descriptor.
 497  */
 498
 499 void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 500 {
 501         sysfs_hash_and_remove(kobj->sd, attr->attr.name);
 502 }
 503
 504 EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
 505 EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);