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