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