1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/seq_file.c 4 * 5 * helper functions for making synthetic files from sequences of records. 6 * initial implementation -- AV, Oct 2001. 7 */ 8 9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 11 #include <linux/cache.h> 12 #include <linux/fs.h> 13 #include <linux/export.h> 14 #include <linux/seq_file.h> 15 #include <linux/vmalloc.h> 16 #include <linux/slab.h> 17 #include <linux/cred.h> 18 #include <linux/mm.h> 19 #include <linux/printk.h> 20 #include <linux/string_helpers.h> 21 22 #include <linux/uaccess.h> 23 #include <asm/page.h> 24 25 static struct kmem_cache *seq_file_cache __ro_after_init; 26 27 static void seq_set_overflow(struct seq_file *m) 28 { 29 m->count = m->size; 30 } 31 32 static void *seq_buf_alloc(unsigned long size) 33 { 34 return kvmalloc(size, GFP_KERNEL_ACCOUNT); 35 } 36 37 /** 38 * seq_open - initialize sequential file 39 * @file: file we initialize 40 * @op: method table describing the sequence 41 * 42 * seq_open() sets @file, associating it with a sequence described 43 * by @op. @op->start() sets the iterator up and returns the first 44 * element of sequence. @op->stop() shuts it down. @op->next() 45 * returns the next element of sequence. @op->show() prints element 46 * into the buffer. In case of error ->start() and ->next() return 47 * ERR_PTR(error). In the end of sequence they return %NULL. ->show() 48 * returns 0 in case of success and negative number in case of error. 49 * Returning SEQ_SKIP means "discard this element and move on". 50 * Note: seq_open() will allocate a struct seq_file and store its 51 * pointer in @file->private_data. This pointer should not be modified. 52 */ 53 int seq_open(struct file *file, const struct seq_operations *op) 54 { 55 struct seq_file *p; 56 57 WARN_ON(file->private_data); 58 59 p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL); 60 if (!p) 61 return -ENOMEM; 62 63 file->private_data = p; 64 65 mutex_init(&p->lock); 66 p->op = op; 67 68 // No refcounting: the lifetime of 'p' is constrained 69 // to the lifetime of the file. 70 p->file = file; 71 72 /* 73 * seq_files support lseek() and pread(). They do not implement 74 * write() at all, but we clear FMODE_PWRITE here for historical 75 * reasons. 76 * 77 * If a client of seq_files a) implements file.write() and b) wishes to 78 * support pwrite() then that client will need to implement its own 79 * file.open() which calls seq_open() and then sets FMODE_PWRITE. 80 */ 81 file->f_mode &= ~FMODE_PWRITE; 82 return 0; 83 } 84 EXPORT_SYMBOL(seq_open); 85 86 static int traverse(struct seq_file *m, loff_t offset) 87 { 88 loff_t pos = 0; 89 int error = 0; 90 void *p; 91 92 m->index = 0; 93 m->count = m->from = 0; 94 if (!offset) 95 return 0; 96 97 if (!m->buf) { 98 m->buf = seq_buf_alloc(m->size = PAGE_SIZE); 99 if (!m->buf) 100 return -ENOMEM; 101 } 102 p = m->op->start(m, &m->index); 103 while (p) { 104 error = PTR_ERR(p); 105 if (IS_ERR(p)) 106 break; 107 error = m->op->show(m, p); 108 if (error < 0) 109 break; 110 if (unlikely(error)) { 111 error = 0; 112 m->count = 0; 113 } 114 if (seq_has_overflowed(m)) 115 goto Eoverflow; 116 p = m->op->next(m, p, &m->index); 117 if (pos + m->count > offset) { 118 m->from = offset - pos; 119 m->count -= m->from; 120 break; 121 } 122 pos += m->count; 123 m->count = 0; 124 if (pos == offset) 125 break; 126 } 127 m->op->stop(m, p); 128 return error; 129 130 Eoverflow: 131 m->op->stop(m, p); 132 kvfree(m->buf); 133 m->count = 0; 134 m->buf = seq_buf_alloc(m->size <<= 1); 135 return !m->buf ? -ENOMEM : -EAGAIN; 136 } 137 138 /** 139 * seq_read - ->read() method for sequential files. 140 * @file: the file to read from 141 * @buf: the buffer to read to 142 * @size: the maximum number of bytes to read 143 * @ppos: the current position in the file 144 * 145 * Ready-made ->f_op->read() 146 */ 147 ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) 148 { 149 struct seq_file *m = file->private_data; 150 size_t copied = 0; 151 size_t n; 152 void *p; 153 int err = 0; 154 155 mutex_lock(&m->lock); 156 157 /* 158 * if request is to read from zero offset, reset iterator to first 159 * record as it might have been already advanced by previous requests 160 */ 161 if (*ppos == 0) { 162 m->index = 0; 163 m->count = 0; 164 } 165 166 /* Don't assume *ppos is where we left it */ 167 if (unlikely(*ppos != m->read_pos)) { 168 while ((err = traverse(m, *ppos)) == -EAGAIN) 169 ; 170 if (err) { 171 /* With prejudice... */ 172 m->read_pos = 0; 173 m->index = 0; 174 m->count = 0; 175 goto Done; 176 } else { 177 m->read_pos = *ppos; 178 } 179 } 180 181 /* grab buffer if we didn't have one */ 182 if (!m->buf) { 183 m->buf = seq_buf_alloc(m->size = PAGE_SIZE); 184 if (!m->buf) 185 goto Enomem; 186 } 187 /* if not empty - flush it first */ 188 if (m->count) { 189 n = min(m->count, size); 190 err = copy_to_user(buf, m->buf + m->from, n); 191 if (err) 192 goto Efault; 193 m->count -= n; 194 m->from += n; 195 size -= n; 196 buf += n; 197 copied += n; 198 if (!size) 199 goto Done; 200 } 201 /* we need at least one record in buffer */ 202 m->from = 0; 203 p = m->op->start(m, &m->index); 204 while (1) { 205 err = PTR_ERR(p); 206 if (!p || IS_ERR(p)) 207 break; 208 err = m->op->show(m, p); 209 if (err < 0) 210 break; 211 if (unlikely(err)) 212 m->count = 0; 213 if (unlikely(!m->count)) { 214 p = m->op->next(m, p, &m->index); 215 continue; 216 } 217 if (m->count < m->size) 218 goto Fill; 219 m->op->stop(m, p); 220 kvfree(m->buf); 221 m->count = 0; 222 m->buf = seq_buf_alloc(m->size <<= 1); 223 if (!m->buf) 224 goto Enomem; 225 p = m->op->start(m, &m->index); 226 } 227 m->op->stop(m, p); 228 m->count = 0; 229 goto Done; 230 Fill: 231 /* they want more? let's try to get some more */ 232 while (1) { 233 size_t offs = m->count; 234 loff_t pos = m->index; 235 236 p = m->op->next(m, p, &m->index); 237 if (pos == m->index) { 238 pr_info_ratelimited("buggy .next function %ps did not update position index\n", 239 m->op->next); 240 m->index++; 241 } 242 if (!p || IS_ERR(p)) { 243 err = PTR_ERR(p); 244 break; 245 } 246 if (m->count >= size) 247 break; 248 err = m->op->show(m, p); 249 if (seq_has_overflowed(m) || err) { 250 m->count = offs; 251 if (likely(err <= 0)) 252 break; 253 } 254 } 255 m->op->stop(m, p); 256 n = min(m->count, size); 257 err = copy_to_user(buf, m->buf, n); 258 if (err) 259 goto Efault; 260 copied += n; 261 m->count -= n; 262 m->from = n; 263 Done: 264 if (!copied) 265 copied = err; 266 else { 267 *ppos += copied; 268 m->read_pos += copied; 269 } 270 mutex_unlock(&m->lock); 271 return copied; 272 Enomem: 273 err = -ENOMEM; 274 goto Done; 275 Efault: 276 err = -EFAULT; 277 goto Done; 278 } 279 EXPORT_SYMBOL(seq_read); 280 281 /** 282 * seq_lseek - ->llseek() method for sequential files. 283 * @file: the file in question 284 * @offset: new position 285 * @whence: 0 for absolute, 1 for relative position 286 * 287 * Ready-made ->f_op->llseek() 288 */ 289 loff_t seq_lseek(struct file *file, loff_t offset, int whence) 290 { 291 struct seq_file *m = file->private_data; 292 loff_t retval = -EINVAL; 293 294 mutex_lock(&m->lock); 295 switch (whence) { 296 case SEEK_CUR: 297 offset += file->f_pos; 298 /* fall through */ 299 case SEEK_SET: 300 if (offset < 0) 301 break; 302 retval = offset; 303 if (offset != m->read_pos) { 304 while ((retval = traverse(m, offset)) == -EAGAIN) 305 ; 306 if (retval) { 307 /* with extreme prejudice... */ 308 file->f_pos = 0; 309 m->read_pos = 0; 310 m->index = 0; 311 m->count = 0; 312 } else { 313 m->read_pos = offset; 314 retval = file->f_pos = offset; 315 } 316 } else { 317 file->f_pos = offset; 318 } 319 } 320 mutex_unlock(&m->lock); 321 return retval; 322 } 323 EXPORT_SYMBOL(seq_lseek); 324 325 /** 326 * seq_release - free the structures associated with sequential file. 327 * @file: file in question 328 * @inode: its inode 329 * 330 * Frees the structures associated with sequential file; can be used 331 * as ->f_op->release() if you don't have private data to destroy. 332 */ 333 int seq_release(struct inode *inode, struct file *file) 334 { 335 struct seq_file *m = file->private_data; 336 kvfree(m->buf); 337 kmem_cache_free(seq_file_cache, m); 338 return 0; 339 } 340 EXPORT_SYMBOL(seq_release); 341 342 /** 343 * seq_escape - print string into buffer, escaping some characters 344 * @m: target buffer 345 * @s: string 346 * @esc: set of characters that need escaping 347 * 348 * Puts string into buffer, replacing each occurrence of character from 349 * @esc with usual octal escape. 350 * Use seq_has_overflowed() to check for errors. 351 */ 352 void seq_escape(struct seq_file *m, const char *s, const char *esc) 353 { 354 char *buf; 355 size_t size = seq_get_buf(m, &buf); 356 int ret; 357 358 ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc); 359 seq_commit(m, ret < size ? ret : -1); 360 } 361 EXPORT_SYMBOL(seq_escape); 362 363 void seq_escape_mem_ascii(struct seq_file *m, const char *src, size_t isz) 364 { 365 char *buf; 366 size_t size = seq_get_buf(m, &buf); 367 int ret; 368 369 ret = string_escape_mem_ascii(src, isz, buf, size); 370 seq_commit(m, ret < size ? ret : -1); 371 } 372 EXPORT_SYMBOL(seq_escape_mem_ascii); 373 374 void seq_vprintf(struct seq_file *m, const char *f, va_list args) 375 { 376 int len; 377 378 if (m->count < m->size) { 379 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args); 380 if (m->count + len < m->size) { 381 m->count += len; 382 return; 383 } 384 } 385 seq_set_overflow(m); 386 } 387 EXPORT_SYMBOL(seq_vprintf); 388 389 void seq_printf(struct seq_file *m, const char *f, ...) 390 { 391 va_list args; 392 393 va_start(args, f); 394 seq_vprintf(m, f, args); 395 va_end(args); 396 } 397 EXPORT_SYMBOL(seq_printf); 398 399 /** 400 * mangle_path - mangle and copy path to buffer beginning 401 * @s: buffer start 402 * @p: beginning of path in above buffer 403 * @esc: set of characters that need escaping 404 * 405 * Copy the path from @p to @s, replacing each occurrence of character from 406 * @esc with usual octal escape. 407 * Returns pointer past last written character in @s, or NULL in case of 408 * failure. 409 */ 410 char *mangle_path(char *s, const char *p, const char *esc) 411 { 412 while (s <= p) { 413 char c = *p++; 414 if (!c) { 415 return s; 416 } else if (!strchr(esc, c)) { 417 *s++ = c; 418 } else if (s + 4 > p) { 419 break; 420 } else { 421 *s++ = '\\'; 422 *s++ = '0' + ((c & 0300) >> 6); 423 *s++ = '0' + ((c & 070) >> 3); 424 *s++ = '0' + (c & 07); 425 } 426 } 427 return NULL; 428 } 429 EXPORT_SYMBOL(mangle_path); 430 431 /** 432 * seq_path - seq_file interface to print a pathname 433 * @m: the seq_file handle 434 * @path: the struct path to print 435 * @esc: set of characters to escape in the output 436 * 437 * return the absolute path of 'path', as represented by the 438 * dentry / mnt pair in the path parameter. 439 */ 440 int seq_path(struct seq_file *m, const struct path *path, const char *esc) 441 { 442 char *buf; 443 size_t size = seq_get_buf(m, &buf); 444 int res = -1; 445 446 if (size) { 447 char *p = d_path(path, buf, size); 448 if (!IS_ERR(p)) { 449 char *end = mangle_path(buf, p, esc); 450 if (end) 451 res = end - buf; 452 } 453 } 454 seq_commit(m, res); 455 456 return res; 457 } 458 EXPORT_SYMBOL(seq_path); 459 460 /** 461 * seq_file_path - seq_file interface to print a pathname of a file 462 * @m: the seq_file handle 463 * @file: the struct file to print 464 * @esc: set of characters to escape in the output 465 * 466 * return the absolute path to the file. 467 */ 468 int seq_file_path(struct seq_file *m, struct file *file, const char *esc) 469 { 470 return seq_path(m, &file->f_path, esc); 471 } 472 EXPORT_SYMBOL(seq_file_path); 473 474 /* 475 * Same as seq_path, but relative to supplied root. 476 */ 477 int seq_path_root(struct seq_file *m, const struct path *path, 478 const struct path *root, const char *esc) 479 { 480 char *buf; 481 size_t size = seq_get_buf(m, &buf); 482 int res = -ENAMETOOLONG; 483 484 if (size) { 485 char *p; 486 487 p = __d_path(path, root, buf, size); 488 if (!p) 489 return SEQ_SKIP; 490 res = PTR_ERR(p); 491 if (!IS_ERR(p)) { 492 char *end = mangle_path(buf, p, esc); 493 if (end) 494 res = end - buf; 495 else 496 res = -ENAMETOOLONG; 497 } 498 } 499 seq_commit(m, res); 500 501 return res < 0 && res != -ENAMETOOLONG ? res : 0; 502 } 503 504 /* 505 * returns the path of the 'dentry' from the root of its filesystem. 506 */ 507 int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc) 508 { 509 char *buf; 510 size_t size = seq_get_buf(m, &buf); 511 int res = -1; 512 513 if (size) { 514 char *p = dentry_path(dentry, buf, size); 515 if (!IS_ERR(p)) { 516 char *end = mangle_path(buf, p, esc); 517 if (end) 518 res = end - buf; 519 } 520 } 521 seq_commit(m, res); 522 523 return res; 524 } 525 EXPORT_SYMBOL(seq_dentry); 526 527 static void *single_start(struct seq_file *p, loff_t *pos) 528 { 529 return NULL + (*pos == 0); 530 } 531 532 static void *single_next(struct seq_file *p, void *v, loff_t *pos) 533 { 534 ++*pos; 535 return NULL; 536 } 537 538 static void single_stop(struct seq_file *p, void *v) 539 { 540 } 541 542 int single_open(struct file *file, int (*show)(struct seq_file *, void *), 543 void *data) 544 { 545 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL_ACCOUNT); 546 int res = -ENOMEM; 547 548 if (op) { 549 op->start = single_start; 550 op->next = single_next; 551 op->stop = single_stop; 552 op->show = show; 553 res = seq_open(file, op); 554 if (!res) 555 ((struct seq_file *)file->private_data)->private = data; 556 else 557 kfree(op); 558 } 559 return res; 560 } 561 EXPORT_SYMBOL(single_open); 562 563 int single_open_size(struct file *file, int (*show)(struct seq_file *, void *), 564 void *data, size_t size) 565 { 566 char *buf = seq_buf_alloc(size); 567 int ret; 568 if (!buf) 569 return -ENOMEM; 570 ret = single_open(file, show, data); 571 if (ret) { 572 kvfree(buf); 573 return ret; 574 } 575 ((struct seq_file *)file->private_data)->buf = buf; 576 ((struct seq_file *)file->private_data)->size = size; 577 return 0; 578 } 579 EXPORT_SYMBOL(single_open_size); 580 581 int single_release(struct inode *inode, struct file *file) 582 { 583 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op; 584 int res = seq_release(inode, file); 585 kfree(op); 586 return res; 587 } 588 EXPORT_SYMBOL(single_release); 589 590 int seq_release_private(struct inode *inode, struct file *file) 591 { 592 struct seq_file *seq = file->private_data; 593 594 kfree(seq->private); 595 seq->private = NULL; 596 return seq_release(inode, file); 597 } 598 EXPORT_SYMBOL(seq_release_private); 599 600 void *__seq_open_private(struct file *f, const struct seq_operations *ops, 601 int psize) 602 { 603 int rc; 604 void *private; 605 struct seq_file *seq; 606 607 private = kzalloc(psize, GFP_KERNEL_ACCOUNT); 608 if (private == NULL) 609 goto out; 610 611 rc = seq_open(f, ops); 612 if (rc < 0) 613 goto out_free; 614 615 seq = f->private_data; 616 seq->private = private; 617 return private; 618 619 out_free: 620 kfree(private); 621 out: 622 return NULL; 623 } 624 EXPORT_SYMBOL(__seq_open_private); 625 626 int seq_open_private(struct file *filp, const struct seq_operations *ops, 627 int psize) 628 { 629 return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM; 630 } 631 EXPORT_SYMBOL(seq_open_private); 632 633 void seq_putc(struct seq_file *m, char c) 634 { 635 if (m->count >= m->size) 636 return; 637 638 m->buf[m->count++] = c; 639 } 640 EXPORT_SYMBOL(seq_putc); 641 642 void seq_puts(struct seq_file *m, const char *s) 643 { 644 int len = strlen(s); 645 646 if (m->count + len >= m->size) { 647 seq_set_overflow(m); 648 return; 649 } 650 memcpy(m->buf + m->count, s, len); 651 m->count += len; 652 } 653 EXPORT_SYMBOL(seq_puts); 654 655 /** 656 * A helper routine for putting decimal numbers without rich format of printf(). 657 * only 'unsigned long long' is supported. 658 * @m: seq_file identifying the buffer to which data should be written 659 * @delimiter: a string which is printed before the number 660 * @num: the number 661 * @width: a minimum field width 662 * 663 * This routine will put strlen(delimiter) + number into seq_filed. 664 * This routine is very quick when you show lots of numbers. 665 * In usual cases, it will be better to use seq_printf(). It's easier to read. 666 */ 667 void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter, 668 unsigned long long num, unsigned int width) 669 { 670 int len; 671 672 if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */ 673 goto overflow; 674 675 if (delimiter && delimiter[0]) { 676 if (delimiter[1] == 0) 677 seq_putc(m, delimiter[0]); 678 else 679 seq_puts(m, delimiter); 680 } 681 682 if (!width) 683 width = 1; 684 685 if (m->count + width >= m->size) 686 goto overflow; 687 688 len = num_to_str(m->buf + m->count, m->size - m->count, num, width); 689 if (!len) 690 goto overflow; 691 692 m->count += len; 693 return; 694 695 overflow: 696 seq_set_overflow(m); 697 } 698 699 void seq_put_decimal_ull(struct seq_file *m, const char *delimiter, 700 unsigned long long num) 701 { 702 return seq_put_decimal_ull_width(m, delimiter, num, 0); 703 } 704 EXPORT_SYMBOL(seq_put_decimal_ull); 705 706 /** 707 * seq_put_hex_ll - put a number in hexadecimal notation 708 * @m: seq_file identifying the buffer to which data should be written 709 * @delimiter: a string which is printed before the number 710 * @v: the number 711 * @width: a minimum field width 712 * 713 * seq_put_hex_ll(m, "", v, 8) is equal to seq_printf(m, "%08llx", v) 714 * 715 * This routine is very quick when you show lots of numbers. 716 * In usual cases, it will be better to use seq_printf(). It's easier to read. 717 */ 718 void seq_put_hex_ll(struct seq_file *m, const char *delimiter, 719 unsigned long long v, unsigned int width) 720 { 721 unsigned int len; 722 int i; 723 724 if (delimiter && delimiter[0]) { 725 if (delimiter[1] == 0) 726 seq_putc(m, delimiter[0]); 727 else 728 seq_puts(m, delimiter); 729 } 730 731 /* If x is 0, the result of __builtin_clzll is undefined */ 732 if (v == 0) 733 len = 1; 734 else 735 len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4; 736 737 if (len < width) 738 len = width; 739 740 if (m->count + len > m->size) { 741 seq_set_overflow(m); 742 return; 743 } 744 745 for (i = len - 1; i >= 0; i--) { 746 m->buf[m->count + i] = hex_asc[0xf & v]; 747 v = v >> 4; 748 } 749 m->count += len; 750 } 751 752 void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num) 753 { 754 int len; 755 756 if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */ 757 goto overflow; 758 759 if (delimiter && delimiter[0]) { 760 if (delimiter[1] == 0) 761 seq_putc(m, delimiter[0]); 762 else 763 seq_puts(m, delimiter); 764 } 765 766 if (m->count + 2 >= m->size) 767 goto overflow; 768 769 if (num < 0) { 770 m->buf[m->count++] = '-'; 771 num = -num; 772 } 773 774 if (num < 10) { 775 m->buf[m->count++] = num + '0'; 776 return; 777 } 778 779 len = num_to_str(m->buf + m->count, m->size - m->count, num, 0); 780 if (!len) 781 goto overflow; 782 783 m->count += len; 784 return; 785 786 overflow: 787 seq_set_overflow(m); 788 } 789 EXPORT_SYMBOL(seq_put_decimal_ll); 790 791 /** 792 * seq_write - write arbitrary data to buffer 793 * @seq: seq_file identifying the buffer to which data should be written 794 * @data: data address 795 * @len: number of bytes 796 * 797 * Return 0 on success, non-zero otherwise. 798 */ 799 int seq_write(struct seq_file *seq, const void *data, size_t len) 800 { 801 if (seq->count + len < seq->size) { 802 memcpy(seq->buf + seq->count, data, len); 803 seq->count += len; 804 return 0; 805 } 806 seq_set_overflow(seq); 807 return -1; 808 } 809 EXPORT_SYMBOL(seq_write); 810 811 /** 812 * seq_pad - write padding spaces to buffer 813 * @m: seq_file identifying the buffer to which data should be written 814 * @c: the byte to append after padding if non-zero 815 */ 816 void seq_pad(struct seq_file *m, char c) 817 { 818 int size = m->pad_until - m->count; 819 if (size > 0) { 820 if (size + m->count > m->size) { 821 seq_set_overflow(m); 822 return; 823 } 824 memset(m->buf + m->count, ' ', size); 825 m->count += size; 826 } 827 if (c) 828 seq_putc(m, c); 829 } 830 EXPORT_SYMBOL(seq_pad); 831 832 /* A complete analogue of print_hex_dump() */ 833 void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type, 834 int rowsize, int groupsize, const void *buf, size_t len, 835 bool ascii) 836 { 837 const u8 *ptr = buf; 838 int i, linelen, remaining = len; 839 char *buffer; 840 size_t size; 841 int ret; 842 843 if (rowsize != 16 && rowsize != 32) 844 rowsize = 16; 845 846 for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) { 847 linelen = min(remaining, rowsize); 848 remaining -= rowsize; 849 850 switch (prefix_type) { 851 case DUMP_PREFIX_ADDRESS: 852 seq_printf(m, "%s%p: ", prefix_str, ptr + i); 853 break; 854 case DUMP_PREFIX_OFFSET: 855 seq_printf(m, "%s%.8x: ", prefix_str, i); 856 break; 857 default: 858 seq_printf(m, "%s", prefix_str); 859 break; 860 } 861 862 size = seq_get_buf(m, &buffer); 863 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize, 864 buffer, size, ascii); 865 seq_commit(m, ret < size ? ret : -1); 866 867 seq_putc(m, '\n'); 868 } 869 } 870 EXPORT_SYMBOL(seq_hex_dump); 871 872 struct list_head *seq_list_start(struct list_head *head, loff_t pos) 873 { 874 struct list_head *lh; 875 876 list_for_each(lh, head) 877 if (pos-- == 0) 878 return lh; 879 880 return NULL; 881 } 882 EXPORT_SYMBOL(seq_list_start); 883 884 struct list_head *seq_list_start_head(struct list_head *head, loff_t pos) 885 { 886 if (!pos) 887 return head; 888 889 return seq_list_start(head, pos - 1); 890 } 891 EXPORT_SYMBOL(seq_list_start_head); 892 893 struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos) 894 { 895 struct list_head *lh; 896 897 lh = ((struct list_head *)v)->next; 898 ++*ppos; 899 return lh == head ? NULL : lh; 900 } 901 EXPORT_SYMBOL(seq_list_next); 902 903 /** 904 * seq_hlist_start - start an iteration of a hlist 905 * @head: the head of the hlist 906 * @pos: the start position of the sequence 907 * 908 * Called at seq_file->op->start(). 909 */ 910 struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos) 911 { 912 struct hlist_node *node; 913 914 hlist_for_each(node, head) 915 if (pos-- == 0) 916 return node; 917 return NULL; 918 } 919 EXPORT_SYMBOL(seq_hlist_start); 920 921 /** 922 * seq_hlist_start_head - start an iteration of a hlist 923 * @head: the head of the hlist 924 * @pos: the start position of the sequence 925 * 926 * Called at seq_file->op->start(). Call this function if you want to 927 * print a header at the top of the output. 928 */ 929 struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos) 930 { 931 if (!pos) 932 return SEQ_START_TOKEN; 933 934 return seq_hlist_start(head, pos - 1); 935 } 936 EXPORT_SYMBOL(seq_hlist_start_head); 937 938 /** 939 * seq_hlist_next - move to the next position of the hlist 940 * @v: the current iterator 941 * @head: the head of the hlist 942 * @ppos: the current position 943 * 944 * Called at seq_file->op->next(). 945 */ 946 struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head, 947 loff_t *ppos) 948 { 949 struct hlist_node *node = v; 950 951 ++*ppos; 952 if (v == SEQ_START_TOKEN) 953 return head->first; 954 else 955 return node->next; 956 } 957 EXPORT_SYMBOL(seq_hlist_next); 958 959 /** 960 * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU 961 * @head: the head of the hlist 962 * @pos: the start position of the sequence 963 * 964 * Called at seq_file->op->start(). 965 * 966 * This list-traversal primitive may safely run concurrently with 967 * the _rcu list-mutation primitives such as hlist_add_head_rcu() 968 * as long as the traversal is guarded by rcu_read_lock(). 969 */ 970 struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head, 971 loff_t pos) 972 { 973 struct hlist_node *node; 974 975 __hlist_for_each_rcu(node, head) 976 if (pos-- == 0) 977 return node; 978 return NULL; 979 } 980 EXPORT_SYMBOL(seq_hlist_start_rcu); 981 982 /** 983 * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU 984 * @head: the head of the hlist 985 * @pos: the start position of the sequence 986 * 987 * Called at seq_file->op->start(). Call this function if you want to 988 * print a header at the top of the output. 989 * 990 * This list-traversal primitive may safely run concurrently with 991 * the _rcu list-mutation primitives such as hlist_add_head_rcu() 992 * as long as the traversal is guarded by rcu_read_lock(). 993 */ 994 struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head, 995 loff_t pos) 996 { 997 if (!pos) 998 return SEQ_START_TOKEN; 999 1000 return seq_hlist_start_rcu(head, pos - 1); 1001 } 1002 EXPORT_SYMBOL(seq_hlist_start_head_rcu); 1003 1004 /** 1005 * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU 1006 * @v: the current iterator 1007 * @head: the head of the hlist 1008 * @ppos: the current position 1009 * 1010 * Called at seq_file->op->next(). 1011 * 1012 * This list-traversal primitive may safely run concurrently with 1013 * the _rcu list-mutation primitives such as hlist_add_head_rcu() 1014 * as long as the traversal is guarded by rcu_read_lock(). 1015 */ 1016 struct hlist_node *seq_hlist_next_rcu(void *v, 1017 struct hlist_head *head, 1018 loff_t *ppos) 1019 { 1020 struct hlist_node *node = v; 1021 1022 ++*ppos; 1023 if (v == SEQ_START_TOKEN) 1024 return rcu_dereference(head->first); 1025 else 1026 return rcu_dereference(node->next); 1027 } 1028 EXPORT_SYMBOL(seq_hlist_next_rcu); 1029 1030 /** 1031 * seq_hlist_start_precpu - start an iteration of a percpu hlist array 1032 * @head: pointer to percpu array of struct hlist_heads 1033 * @cpu: pointer to cpu "cursor" 1034 * @pos: start position of sequence 1035 * 1036 * Called at seq_file->op->start(). 1037 */ 1038 struct hlist_node * 1039 seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos) 1040 { 1041 struct hlist_node *node; 1042 1043 for_each_possible_cpu(*cpu) { 1044 hlist_for_each(node, per_cpu_ptr(head, *cpu)) { 1045 if (pos-- == 0) 1046 return node; 1047 } 1048 } 1049 return NULL; 1050 } 1051 EXPORT_SYMBOL(seq_hlist_start_percpu); 1052 1053 /** 1054 * seq_hlist_next_percpu - move to the next position of the percpu hlist array 1055 * @v: pointer to current hlist_node 1056 * @head: pointer to percpu array of struct hlist_heads 1057 * @cpu: pointer to cpu "cursor" 1058 * @pos: start position of sequence 1059 * 1060 * Called at seq_file->op->next(). 1061 */ 1062 struct hlist_node * 1063 seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, 1064 int *cpu, loff_t *pos) 1065 { 1066 struct hlist_node *node = v; 1067 1068 ++*pos; 1069 1070 if (node->next) 1071 return node->next; 1072 1073 for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids; 1074 *cpu = cpumask_next(*cpu, cpu_possible_mask)) { 1075 struct hlist_head *bucket = per_cpu_ptr(head, *cpu); 1076 1077 if (!hlist_empty(bucket)) 1078 return bucket->first; 1079 } 1080 return NULL; 1081 } 1082 EXPORT_SYMBOL(seq_hlist_next_percpu); 1083 1084 void __init seq_file_init(void) 1085 { 1086 seq_file_cache = KMEM_CACHE(seq_file, SLAB_ACCOUNT|SLAB_PANIC); 1087 } 1088