Blame view
fs/configfs/file.c
15.3 KB
7063fbf22 [PATCH] configfs:... |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 |
/* -*- mode: c; c-basic-offset: 8; -*- * vim: noexpandtab sw=8 ts=8 sts=0: * * file.c - operations for regular (text) files. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. * * Based on sysfs: * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel * * configfs Copyright (C) 2005 Oracle. All rights reserved. */ #include <linux/fs.h> #include <linux/module.h> |
7063fbf22 [PATCH] configfs:... |
29 |
#include <linux/slab.h> |
6d748924b [PATCH] configsfs... |
30 |
#include <linux/mutex.h> |
03607ace8 configfs: impleme... |
31 |
#include <linux/vmalloc.h> |
7063fbf22 [PATCH] configfs:... |
32 |
#include <asm/uaccess.h> |
7063fbf22 [PATCH] configfs:... |
33 34 35 |
#include <linux/configfs.h> #include "configfs_internal.h" |
b23cdde4c configfs: consist... |
36 37 38 39 40 41 42 |
/* * A simple attribute can only be 4096 characters. Why 4k? Because the * original code limited it to PAGE_SIZE. That's a bad idea, though, * because an attribute of 16k on ia64 won't work on x86. So we limit to * 4k, our minimum common page size. */ #define SIMPLE_ATTR_SIZE 4096 |
7063fbf22 [PATCH] configfs:... |
43 44 45 46 47 48 |
struct configfs_buffer { size_t count; loff_t pos; char * page; struct configfs_item_operations * ops; |
6d748924b [PATCH] configsfs... |
49 |
struct mutex mutex; |
7063fbf22 [PATCH] configfs:... |
50 |
int needs_read_fill; |
03607ace8 configfs: impleme... |
51 52 53 54 |
bool read_in_progress; bool write_in_progress; char *bin_buffer; int bin_buffer_size; |
7063fbf22 [PATCH] configfs:... |
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 |
}; /** * fill_read_buffer - allocate and fill buffer from item. * @dentry: dentry pointer. * @buffer: data buffer for file. * * Allocate @buffer->page, if it hasn't been already, then call the * config_item's show() method to fill the buffer with this attribute's * data. * This is called only once, on the file's first read. */ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buffer) { struct configfs_attribute * attr = to_attr(dentry); struct config_item * item = to_item(dentry->d_parent); |
7063fbf22 [PATCH] configfs:... |
72 73 74 75 76 77 78 |
int ret = 0; ssize_t count; if (!buffer->page) buffer->page = (char *) get_zeroed_page(GFP_KERNEL); if (!buffer->page) return -ENOMEM; |
517982229 configfs: remove ... |
79 |
count = attr->show(item, buffer->page); |
870823e62 configfs: add sho... |
80 |
|
b23cdde4c configfs: consist... |
81 |
BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE); |
3dc3afade configfs: don't s... |
82 83 |
if (count >= 0) { buffer->needs_read_fill = 0; |
7063fbf22 [PATCH] configfs:... |
84 |
buffer->count = count; |
3dc3afade configfs: don't s... |
85 |
} else |
7063fbf22 [PATCH] configfs:... |
86 87 88 |
ret = count; return ret; } |
7063fbf22 [PATCH] configfs:... |
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 |
/** * configfs_read_file - read an attribute. * @file: file pointer. * @buf: buffer to fill. * @count: number of bytes to read. * @ppos: starting offset in file. * * Userspace wants to read an attribute file. The attribute descriptor * is in the file's ->d_fsdata. The target item is in the directory's * ->d_fsdata. * * We call fill_read_buffer() to allocate and fill the buffer from the * item's show() method exactly once (if the read is happening from * the beginning of the file). That should fill the entire buffer with * all the data the item has to offer for that attribute. * We then call flush_read_buffer() to copy the buffer to userspace * in the increments specified. */ static ssize_t configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct configfs_buffer * buffer = file->private_data; ssize_t retval = 0; |
6d748924b [PATCH] configsfs... |
113 |
mutex_lock(&buffer->mutex); |
7063fbf22 [PATCH] configfs:... |
114 |
if (buffer->needs_read_fill) { |
867fa491a [PATCH] configfs:... |
115 |
if ((retval = fill_read_buffer(file->f_path.dentry,buffer))) |
7063fbf22 [PATCH] configfs:... |
116 117 |
goto out; } |
4779efca1 [PATCH] pr_debug:... |
118 119 |
pr_debug("%s: count = %zd, ppos = %lld, buf = %s ", |
8e24eea72 fs: replace remai... |
120 |
__func__, count, *ppos, buffer->page); |
92f4c701a use simple_read_f... |
121 122 |
retval = simple_read_from_buffer(buf, count, ppos, buffer->page, buffer->count); |
7063fbf22 [PATCH] configfs:... |
123 |
out: |
6d748924b [PATCH] configsfs... |
124 |
mutex_unlock(&buffer->mutex); |
7063fbf22 [PATCH] configfs:... |
125 126 |
return retval; } |
03607ace8 configfs: impleme... |
127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 |
/** * configfs_read_bin_file - read a binary attribute. * @file: file pointer. * @buf: buffer to fill. * @count: number of bytes to read. * @ppos: starting offset in file. * * Userspace wants to read a binary attribute file. The attribute * descriptor is in the file's ->d_fsdata. The target item is in the * directory's ->d_fsdata. * * We check whether we need to refill the buffer. If so we will * call the attributes' attr->read() twice. The first time we * will pass a NULL as a buffer pointer, which the attributes' method * will use to return the size of the buffer required. If no error * occurs we will allocate the buffer using vmalloc and call * attr->read() again passing that buffer as an argument. * Then we just copy to user-space using simple_read_from_buffer. */ static ssize_t configfs_read_bin_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct configfs_buffer *buffer = file->private_data; struct dentry *dentry = file->f_path.dentry; struct config_item *item = to_item(dentry->d_parent); struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry); ssize_t retval = 0; ssize_t len = min_t(size_t, count, PAGE_SIZE); mutex_lock(&buffer->mutex); /* we don't support switching read/write modes */ if (buffer->write_in_progress) { retval = -ETXTBSY; goto out; } buffer->read_in_progress = 1; if (buffer->needs_read_fill) { /* perform first read with buf == NULL to get extent */ len = bin_attr->read(item, NULL, 0); if (len <= 0) { retval = len; goto out; } /* do not exceed the maximum value */ if (bin_attr->cb_max_size && len > bin_attr->cb_max_size) { retval = -EFBIG; goto out; } buffer->bin_buffer = vmalloc(len); if (buffer->bin_buffer == NULL) { retval = -ENOMEM; goto out; } buffer->bin_buffer_size = len; /* perform second read to fill buffer */ len = bin_attr->read(item, buffer->bin_buffer, len); if (len < 0) { retval = len; vfree(buffer->bin_buffer); buffer->bin_buffer_size = 0; buffer->bin_buffer = NULL; goto out; } buffer->needs_read_fill = 0; } retval = simple_read_from_buffer(buf, count, ppos, buffer->bin_buffer, buffer->bin_buffer_size); out: mutex_unlock(&buffer->mutex); return retval; } |
7063fbf22 [PATCH] configfs:... |
207 208 209 210 |
/** * fill_write_buffer - copy buffer from userspace. * @buffer: data buffer for file. |
3d0f89bb1 configfs: Add per... |
211 |
* @buf: data from user. |
7063fbf22 [PATCH] configfs:... |
212 213 214 215 216 217 218 219 220 221 222 223 |
* @count: number of bytes in @userbuf. * * Allocate @buffer->page if it hasn't been already, then * copy the user-supplied buffer into it. */ static int fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size_t count) { int error; if (!buffer->page) |
ff05d1c46 configfs: Zero te... |
224 |
buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0); |
7063fbf22 [PATCH] configfs:... |
225 226 |
if (!buffer->page) return -ENOMEM; |
b23cdde4c configfs: consist... |
227 228 |
if (count >= SIMPLE_ATTR_SIZE) count = SIMPLE_ATTR_SIZE - 1; |
7063fbf22 [PATCH] configfs:... |
229 230 |
error = copy_from_user(buffer->page,buf,count); buffer->needs_read_fill = 1; |
ff05d1c46 configfs: Zero te... |
231 232 233 |
/* if buf is assumed to contain a string, terminate it by \0, * so e.g. sscanf() can scan the string easily */ buffer->page[count] = 0; |
7063fbf22 [PATCH] configfs:... |
234 235 236 237 238 239 |
return error ? -EFAULT : count; } /** * flush_write_buffer - push buffer to config_item. |
3d0f89bb1 configfs: Add per... |
240 |
* @dentry: dentry to the attribute |
7063fbf22 [PATCH] configfs:... |
241 |
* @buffer: data buffer for file. |
3d0f89bb1 configfs: Add per... |
242 |
* @count: number of bytes |
7063fbf22 [PATCH] configfs:... |
243 244 245 246 247 248 249 250 251 252 253 |
* * Get the correct pointers for the config_item and the attribute we're * dealing with, then call the store() method for the attribute, * passing the buffer that we acquired in fill_write_buffer(). */ static int flush_write_buffer(struct dentry * dentry, struct configfs_buffer * buffer, size_t count) { struct configfs_attribute * attr = to_attr(dentry); struct config_item * item = to_item(dentry->d_parent); |
7063fbf22 [PATCH] configfs:... |
254 |
|
870823e62 configfs: add sho... |
255 |
return attr->store(item, buffer->page, count); |
7063fbf22 [PATCH] configfs:... |
256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 |
} /** * configfs_write_file - write an attribute. * @file: file pointer * @buf: data to write * @count: number of bytes * @ppos: starting offset * * Similar to configfs_read_file(), though working in the opposite direction. * We allocate and fill the data from the user in fill_write_buffer(), * then push it to the config_item in flush_write_buffer(). * There is no easy way for us to know if userspace is only doing a partial * write, so we don't support them. We expect the entire buffer to come * on the first write. * Hint: if you're writing a value, first read the file, modify only the * the value you're changing, then write entire buffer back. */ static ssize_t configfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct configfs_buffer * buffer = file->private_data; |
3d0f89bb1 configfs: Add per... |
280 |
ssize_t len; |
7063fbf22 [PATCH] configfs:... |
281 |
|
6d748924b [PATCH] configsfs... |
282 |
mutex_lock(&buffer->mutex); |
3d0f89bb1 configfs: Add per... |
283 284 |
len = fill_write_buffer(buffer, buf, count); if (len > 0) |
7121064b2 configfs: use cap... |
285 |
len = flush_write_buffer(file->f_path.dentry, buffer, len); |
3d0f89bb1 configfs: Add per... |
286 287 |
if (len > 0) *ppos += len; |
6d748924b [PATCH] configsfs... |
288 |
mutex_unlock(&buffer->mutex); |
3d0f89bb1 configfs: Add per... |
289 |
return len; |
7063fbf22 [PATCH] configfs:... |
290 |
} |
03607ace8 configfs: impleme... |
291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 |
/** * configfs_write_bin_file - write a binary attribute. * @file: file pointer * @buf: data to write * @count: number of bytes * @ppos: starting offset * * Writing to a binary attribute file is similar to a normal read. * We buffer the consecutive writes (binary attribute files do not * support lseek) in a continuously growing buffer, but we don't * commit until the close of the file. */ static ssize_t configfs_write_bin_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct configfs_buffer *buffer = file->private_data; struct dentry *dentry = file->f_path.dentry; struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry); void *tbuf = NULL; ssize_t len; mutex_lock(&buffer->mutex); /* we don't support switching read/write modes */ if (buffer->read_in_progress) { len = -ETXTBSY; goto out; } buffer->write_in_progress = 1; /* buffer grows? */ if (*ppos + count > buffer->bin_buffer_size) { if (bin_attr->cb_max_size && *ppos + count > bin_attr->cb_max_size) { len = -EFBIG; |
42857cf51 configfs: Return ... |
329 |
goto out; |
03607ace8 configfs: impleme... |
330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 |
} tbuf = vmalloc(*ppos + count); if (tbuf == NULL) { len = -ENOMEM; goto out; } /* copy old contents */ if (buffer->bin_buffer) { memcpy(tbuf, buffer->bin_buffer, buffer->bin_buffer_size); vfree(buffer->bin_buffer); } /* clear the new area */ memset(tbuf + buffer->bin_buffer_size, 0, *ppos + count - buffer->bin_buffer_size); buffer->bin_buffer = tbuf; buffer->bin_buffer_size = *ppos + count; } len = simple_write_to_buffer(buffer->bin_buffer, buffer->bin_buffer_size, ppos, buf, count); |
03607ace8 configfs: impleme... |
354 355 356 357 358 359 |
out: mutex_unlock(&buffer->mutex); return len; } static int check_perm(struct inode * inode, struct file * file, int type) |
7063fbf22 [PATCH] configfs:... |
360 |
{ |
867fa491a [PATCH] configfs:... |
361 362 |
struct config_item *item = configfs_get_config_item(file->f_path.dentry->d_parent); struct configfs_attribute * attr = to_attr(file->f_path.dentry); |
03607ace8 configfs: impleme... |
363 |
struct configfs_bin_attribute *bin_attr = NULL; |
7063fbf22 [PATCH] configfs:... |
364 365 366 367 368 369 |
struct configfs_buffer * buffer; struct configfs_item_operations * ops = NULL; int error = 0; if (!item || !attr) goto Einval; |
03607ace8 configfs: impleme... |
370 371 |
if (type & CONFIGFS_ITEM_BIN_ATTR) bin_attr = to_bin_attr(file->f_path.dentry); |
7063fbf22 [PATCH] configfs:... |
372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 |
/* Grab the module reference for this attribute if we have one */ if (!try_module_get(attr->ca_owner)) { error = -ENODEV; goto Done; } if (item->ci_type) ops = item->ci_type->ct_item_ops; else goto Eaccess; /* File needs write support. * The inode's perms must say it's ok, * and we must have a store method. */ if (file->f_mode & FMODE_WRITE) { |
03607ace8 configfs: impleme... |
388 389 390 391 |
if (!(inode->i_mode & S_IWUGO)) goto Eaccess; if ((type & CONFIGFS_ITEM_ATTR) && !attr->store) |
7063fbf22 [PATCH] configfs:... |
392 |
goto Eaccess; |
03607ace8 configfs: impleme... |
393 394 |
if ((type & CONFIGFS_ITEM_BIN_ATTR) && !bin_attr->write) goto Eaccess; |
7063fbf22 [PATCH] configfs:... |
395 396 397 398 399 400 401 |
} /* File needs read support. * The inode's perms must say it's ok, and we there * must be a show method for it. */ if (file->f_mode & FMODE_READ) { |
03607ace8 configfs: impleme... |
402 403 404 405 406 407 408 |
if (!(inode->i_mode & S_IRUGO)) goto Eaccess; if ((type & CONFIGFS_ITEM_ATTR) && !attr->show) goto Eaccess; if ((type & CONFIGFS_ITEM_BIN_ATTR) && !bin_attr->read) |
7063fbf22 [PATCH] configfs:... |
409 410 411 412 413 414 |
goto Eaccess; } /* No error? Great, allocate a buffer for the file, and store it * it in file->private_data for easy access. */ |
f8314dc60 [PATCH] fs: Conve... |
415 |
buffer = kzalloc(sizeof(struct configfs_buffer),GFP_KERNEL); |
559c9ac39 configfs: handle ... |
416 |
if (!buffer) { |
7063fbf22 [PATCH] configfs:... |
417 |
error = -ENOMEM; |
559c9ac39 configfs: handle ... |
418 419 |
goto Enomem; } |
6d748924b [PATCH] configsfs... |
420 |
mutex_init(&buffer->mutex); |
559c9ac39 configfs: handle ... |
421 |
buffer->needs_read_fill = 1; |
03607ace8 configfs: impleme... |
422 423 |
buffer->read_in_progress = 0; buffer->write_in_progress = 0; |
559c9ac39 configfs: handle ... |
424 425 |
buffer->ops = ops; file->private_data = buffer; |
7063fbf22 [PATCH] configfs:... |
426 427 428 429 430 431 432 |
goto Done; Einval: error = -EINVAL; goto Done; Eaccess: error = -EACCES; |
559c9ac39 configfs: handle ... |
433 |
Enomem: |
7063fbf22 [PATCH] configfs:... |
434 435 436 437 438 439 |
module_put(attr->ca_owner); Done: if (error && item) config_item_put(item); return error; } |
03607ace8 configfs: impleme... |
440 |
static int configfs_release(struct inode *inode, struct file *filp) |
7063fbf22 [PATCH] configfs:... |
441 |
{ |
867fa491a [PATCH] configfs:... |
442 443 |
struct config_item * item = to_item(filp->f_path.dentry->d_parent); struct configfs_attribute * attr = to_attr(filp->f_path.dentry); |
7063fbf22 [PATCH] configfs:... |
444 445 446 447 448 449 450 451 452 453 454 |
struct module * owner = attr->ca_owner; struct configfs_buffer * buffer = filp->private_data; if (item) config_item_put(item); /* After this point, attr should not be accessed. */ module_put(owner); if (buffer) { if (buffer->page) free_page((unsigned long)buffer->page); |
6d748924b [PATCH] configsfs... |
455 |
mutex_destroy(&buffer->mutex); |
7063fbf22 [PATCH] configfs:... |
456 457 458 459 |
kfree(buffer); } return 0; } |
03607ace8 configfs: impleme... |
460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 |
static int configfs_open_file(struct inode *inode, struct file *filp) { return check_perm(inode, filp, CONFIGFS_ITEM_ATTR); } static int configfs_open_bin_file(struct inode *inode, struct file *filp) { return check_perm(inode, filp, CONFIGFS_ITEM_BIN_ATTR); } static int configfs_release_bin_file(struct inode *inode, struct file *filp) { struct configfs_buffer *buffer = filp->private_data; struct dentry *dentry = filp->f_path.dentry; struct config_item *item = to_item(dentry->d_parent); struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry); ssize_t len = 0; int ret; buffer->read_in_progress = 0; if (buffer->write_in_progress) { buffer->write_in_progress = 0; len = bin_attr->write(item, buffer->bin_buffer, buffer->bin_buffer_size); /* vfree on NULL is safe */ vfree(buffer->bin_buffer); buffer->bin_buffer = NULL; buffer->bin_buffer_size = 0; buffer->needs_read_fill = 1; } ret = configfs_release(inode, filp); if (len < 0) return len; return ret; } |
4b6f5d20b [PATCH] Make most... |
499 |
const struct file_operations configfs_file_operations = { |
7063fbf22 [PATCH] configfs:... |
500 501 502 503 504 505 |
.read = configfs_read_file, .write = configfs_write_file, .llseek = generic_file_llseek, .open = configfs_open_file, .release = configfs_release, }; |
03607ace8 configfs: impleme... |
506 507 508 509 510 511 512 |
const struct file_operations configfs_bin_file_operations = { .read = configfs_read_bin_file, .write = configfs_write_bin_file, .llseek = NULL, /* bin file is not seekable */ .open = configfs_open_bin_file, .release = configfs_release_bin_file, }; |
7063fbf22 [PATCH] configfs:... |
513 514 515 516 517 518 519 520 |
/** * configfs_create_file - create an attribute file for an item. * @item: item we're creating for. * @attr: atrribute descriptor. */ int configfs_create_file(struct config_item * item, const struct configfs_attribute * attr) { |
28444a2bd configfs_add_file... |
521 522 523 524 |
struct dentry *dir = item->ci_dentry; struct configfs_dirent *parent_sd = dir->d_fsdata; umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG; int error = 0; |
7063fbf22 [PATCH] configfs:... |
525 |
|
5955102c9 wrappers for ->i_... |
526 |
inode_lock_nested(d_inode(dir), I_MUTEX_NORMAL); |
28444a2bd configfs_add_file... |
527 528 |
error = configfs_make_dirent(parent_sd, NULL, (void *) attr, mode, CONFIGFS_ITEM_ATTR); |
5955102c9 wrappers for ->i_... |
529 |
inode_unlock(d_inode(dir)); |
28444a2bd configfs_add_file... |
530 531 |
return error; |
7063fbf22 [PATCH] configfs:... |
532 |
} |
03607ace8 configfs: impleme... |
533 534 535 536 537 538 539 540 541 542 543 544 545 |
/** * configfs_create_bin_file - create a binary attribute file for an item. * @item: item we're creating for. * @attr: atrribute descriptor. */ int configfs_create_bin_file(struct config_item *item, const struct configfs_bin_attribute *bin_attr) { struct dentry *dir = item->ci_dentry; struct configfs_dirent *parent_sd = dir->d_fsdata; umode_t mode = (bin_attr->cb_attr.ca_mode & S_IALLUGO) | S_IFREG; int error = 0; |
5955102c9 wrappers for ->i_... |
546 |
inode_lock_nested(dir->d_inode, I_MUTEX_NORMAL); |
03607ace8 configfs: impleme... |
547 548 |
error = configfs_make_dirent(parent_sd, NULL, (void *) bin_attr, mode, CONFIGFS_ITEM_BIN_ATTR); |
5955102c9 wrappers for ->i_... |
549 |
inode_unlock(dir->d_inode); |
03607ace8 configfs: impleme... |
550 551 552 |
return error; } |