1/* 2 * linux/drivers/net/netconsole.c 3 * 4 * Copyright (C) 2001 Ingo Molnar <mingo@redhat.com> 5 * 6 * This file contains the implementation of an IRQ-safe, crash-safe 7 * kernel console implementation that outputs kernel messages to the 8 * network. 9 * 10 * Modification history: 11 * 12 * 2001-09-17 started by Ingo Molnar. 13 * 2003-08-11 2.6 port by Matt Mackall 14 * simplified options 15 * generic card hooks 16 * works non-modular 17 * 2003-09-07 rewritten with netpoll api 18 */ 19 20/**************************************************************** 21 * This program is free software; you can redistribute it and/or modify 22 * it under the terms of the GNU General Public License as published by 23 * the Free Software Foundation; either version 2, or (at your option) 24 * any later version. 25 * 26 * This program is distributed in the hope that it will be useful, 27 * but WITHOUT ANY WARRANTY; without even the implied warranty of 28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 29 * GNU General Public License for more details. 30 * 31 * You should have received a copy of the GNU General Public License 32 * along with this program; if not, write to the Free Software 33 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 34 * 35 ****************************************************************/ 36 37#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 38 39#include <linux/mm.h> 40#include <linux/init.h> 41#include <linux/module.h> 42#include <linux/slab.h> 43#include <linux/console.h> 44#include <linux/moduleparam.h> 45#include <linux/kernel.h> 46#include <linux/string.h> 47#include <linux/netpoll.h> 48#include <linux/inet.h> 49#include <linux/configfs.h> 50 51MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>"); 52MODULE_DESCRIPTION("Console driver for network interfaces"); 53MODULE_LICENSE("GPL"); 54 55#define MAX_PARAM_LENGTH 256 56#define MAX_PRINT_CHUNK 1000 57 58static char config[MAX_PARAM_LENGTH]; 59module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0); 60MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]"); 61 62static bool oops_only = false; 63module_param(oops_only, bool, 0600); 64MODULE_PARM_DESC(oops_only, "Only log oops messages"); 65 66#ifndef MODULE 67static int __init option_setup(char *opt) 68{ 69 strlcpy(config, opt, MAX_PARAM_LENGTH); 70 return 1; 71} 72__setup("netconsole=", option_setup); 73#endif /* MODULE */ 74 75/* Linked list of all configured targets */ 76static LIST_HEAD(target_list); 77 78/* This needs to be a spinlock because write_msg() cannot sleep */ 79static DEFINE_SPINLOCK(target_list_lock); 80 81/** 82 * struct netconsole_target - Represents a configured netconsole target. 83 * @list: Links this target into the target_list. 84 * @item: Links us into the configfs subsystem hierarchy. 85 * @enabled: On / off knob to enable / disable target. 86 * Visible from userspace (read-write). 87 * We maintain a strict 1:1 correspondence between this and 88 * whether the corresponding netpoll is active or inactive. 89 * Also, other parameters of a target may be modified at 90 * runtime only when it is disabled (enabled == 0). 91 * @np: The netpoll structure for this target. 92 * Contains the other userspace visible parameters: 93 * dev_name (read-write) 94 * local_port (read-write) 95 * remote_port (read-write) 96 * local_ip (read-write) 97 * remote_ip (read-write) 98 * local_mac (read-only) 99 * remote_mac (read-write) 100 */ 101struct netconsole_target { 102 struct list_head list; 103#ifdef CONFIG_NETCONSOLE_DYNAMIC 104 struct config_item item; 105#endif 106 int enabled; 107 struct mutex mutex; 108 struct netpoll np; 109}; 110 111#ifdef CONFIG_NETCONSOLE_DYNAMIC 112 113static struct configfs_subsystem netconsole_subsys; 114 115static int __init dynamic_netconsole_init(void) 116{ 117 config_group_init(&netconsole_subsys.su_group); 118 mutex_init(&netconsole_subsys.su_mutex); 119 return configfs_register_subsystem(&netconsole_subsys); 120} 121 122static void __exit dynamic_netconsole_exit(void) 123{ 124 configfs_unregister_subsystem(&netconsole_subsys); 125} 126 127/* 128 * Targets that were created by parsing the boot/module option string 129 * do not exist in the configfs hierarchy (and have NULL names) and will 130 * never go away, so make these a no-op for them. 131 */ 132static void netconsole_target_get(struct netconsole_target *nt) 133{ 134 if (config_item_name(&nt->item)) 135 config_item_get(&nt->item); 136} 137 138static void netconsole_target_put(struct netconsole_target *nt) 139{ 140 if (config_item_name(&nt->item)) 141 config_item_put(&nt->item); 142} 143 144#else /* !CONFIG_NETCONSOLE_DYNAMIC */ 145 146static int __init dynamic_netconsole_init(void) 147{ 148 return 0; 149} 150 151static void __exit dynamic_netconsole_exit(void) 152{ 153} 154 155/* 156 * No danger of targets going away from under us when dynamic 157 * reconfigurability is off. 158 */ 159static void netconsole_target_get(struct netconsole_target *nt) 160{ 161} 162 163static void netconsole_target_put(struct netconsole_target *nt) 164{ 165} 166 167#endif /* CONFIG_NETCONSOLE_DYNAMIC */ 168 169/* Allocate new target (from boot/module param) and setup netpoll for it */ 170static struct netconsole_target *alloc_param_target(char *target_config) 171{ 172 int err = -ENOMEM; 173 struct netconsole_target *nt; 174 175 /* 176 * Allocate and initialize with defaults. 177 * Note that these targets get their config_item fields zeroed-out. 178 */ 179 nt = kzalloc(sizeof(*nt), GFP_KERNEL); 180 if (!nt) 181 goto fail; 182 183 nt->np.name = "netconsole"; 184 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ); 185 nt->np.local_port = 6665; 186 nt->np.remote_port = 6666; 187 mutex_init(&nt->mutex); 188 memset(nt->np.remote_mac, 0xff, ETH_ALEN); 189 190 /* Parse parameters and setup netpoll */ 191 err = netpoll_parse_options(&nt->np, target_config); 192 if (err) 193 goto fail; 194 195 err = netpoll_setup(&nt->np); 196 if (err) 197 goto fail; 198 199 nt->enabled = 1; 200 201 return nt; 202 203fail: 204 kfree(nt); 205 return ERR_PTR(err); 206} 207 208/* Cleanup netpoll for given target (from boot/module param) and free it */ 209static void free_param_target(struct netconsole_target *nt) 210{ 211 netpoll_cleanup(&nt->np); 212 kfree(nt); 213} 214 215#ifdef CONFIG_NETCONSOLE_DYNAMIC 216 217/* 218 * Our subsystem hierarchy is: 219 * 220 * /sys/kernel/config/netconsole/ 221 * | 222 * <target>/ 223 * | enabled 224 * | dev_name 225 * | local_port 226 * | remote_port 227 * | local_ip 228 * | remote_ip 229 * | local_mac 230 * | remote_mac 231 * | 232 * <target>/... 233 */ 234 235struct netconsole_target_attr { 236 struct configfs_attribute attr; 237 ssize_t (*show)(struct netconsole_target *nt, 238 char *buf); 239 ssize_t (*store)(struct netconsole_target *nt, 240 const char *buf, 241 size_t count); 242}; 243 244static struct netconsole_target *to_target(struct config_item *item) 245{ 246 return item ? 247 container_of(item, struct netconsole_target, item) : 248 NULL; 249} 250 251/* 252 * Attribute operations for netconsole_target. 253 */ 254 255static ssize_t show_enabled(struct netconsole_target *nt, char *buf) 256{ 257 return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled); 258} 259 260static ssize_t show_dev_name(struct netconsole_target *nt, char *buf) 261{ 262 return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name); 263} 264 265static ssize_t show_local_port(struct netconsole_target *nt, char *buf) 266{ 267 return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port); 268} 269 270static ssize_t show_remote_port(struct netconsole_target *nt, char *buf) 271{ 272 return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port); 273} 274 275static ssize_t show_local_ip(struct netconsole_target *nt, char *buf) 276{ 277 if (nt->np.ipv6) 278 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6); 279 else 280 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip); 281} 282 283static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf) 284{ 285 if (nt->np.ipv6) 286 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6); 287 else 288 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip); 289} 290 291static ssize_t show_local_mac(struct netconsole_target *nt, char *buf) 292{ 293 struct net_device *dev = nt->np.dev; 294 static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; 295 296 return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast); 297} 298 299static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf) 300{ 301 return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac); 302} 303 304/* 305 * This one is special -- targets created through the configfs interface 306 * are not enabled (and the corresponding netpoll activated) by default. 307 * The user is expected to set the desired parameters first (which 308 * would enable him to dynamically add new netpoll targets for new 309 * network interfaces as and when they come up). 310 */ 311static ssize_t store_enabled(struct netconsole_target *nt, 312 const char *buf, 313 size_t count) 314{ 315 unsigned long flags; 316 int enabled; 317 int err; 318 319 err = kstrtoint(buf, 10, &enabled); 320 if (err < 0) 321 return err; 322 if (enabled < 0 || enabled > 1) 323 return -EINVAL; 324 if (enabled == nt->enabled) { 325 pr_info("network logging has already %s\n", 326 nt->enabled ? "started" : "stopped"); 327 return -EINVAL; 328 } 329 330 if (enabled) { /* 1 */ 331 /* 332 * Skip netpoll_parse_options() -- all the attributes are 333 * already configured via configfs. Just print them out. 334 */ 335 netpoll_print_options(&nt->np); 336 337 err = netpoll_setup(&nt->np); 338 if (err) 339 return err; 340 341 pr_info("netconsole: network logging started\n"); 342 } else { /* 0 */ 343 /* We need to disable the netconsole before cleaning it up 344 * otherwise we might end up in write_msg() with 345 * nt->np.dev == NULL and nt->enabled == 1 346 */ 347 spin_lock_irqsave(&target_list_lock, flags); 348 nt->enabled = 0; 349 spin_unlock_irqrestore(&target_list_lock, flags); 350 netpoll_cleanup(&nt->np); 351 } 352 353 nt->enabled = enabled; 354 355 return strnlen(buf, count); 356} 357 358static ssize_t store_dev_name(struct netconsole_target *nt, 359 const char *buf, 360 size_t count) 361{ 362 size_t len; 363 364 if (nt->enabled) { 365 pr_err("target (%s) is enabled, disable to update parameters\n", 366 config_item_name(&nt->item)); 367 return -EINVAL; 368 } 369 370 strlcpy(nt->np.dev_name, buf, IFNAMSIZ); 371 372 /* Get rid of possible trailing newline from echo(1) */ 373 len = strnlen(nt->np.dev_name, IFNAMSIZ); 374 if (nt->np.dev_name[len - 1] == '\n') 375 nt->np.dev_name[len - 1] = '\0'; 376 377 return strnlen(buf, count); 378} 379 380static ssize_t store_local_port(struct netconsole_target *nt, 381 const char *buf, 382 size_t count) 383{ 384 int rv; 385 386 if (nt->enabled) { 387 pr_err("target (%s) is enabled, disable to update parameters\n", 388 config_item_name(&nt->item)); 389 return -EINVAL; 390 } 391 392 rv = kstrtou16(buf, 10, &nt->np.local_port); 393 if (rv < 0) 394 return rv; 395 return strnlen(buf, count); 396} 397 398static ssize_t store_remote_port(struct netconsole_target *nt, 399 const char *buf, 400 size_t count) 401{ 402 int rv; 403 404 if (nt->enabled) { 405 pr_err("target (%s) is enabled, disable to update parameters\n", 406 config_item_name(&nt->item)); 407 return -EINVAL; 408 } 409 410 rv = kstrtou16(buf, 10, &nt->np.remote_port); 411 if (rv < 0) 412 return rv; 413 return strnlen(buf, count); 414} 415 416static ssize_t store_local_ip(struct netconsole_target *nt, 417 const char *buf, 418 size_t count) 419{ 420 if (nt->enabled) { 421 pr_err("target (%s) is enabled, disable to update parameters\n", 422 config_item_name(&nt->item)); 423 return -EINVAL; 424 } 425 426 if (strnchr(buf, count, ':')) { 427 const char *end; 428 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) { 429 if (*end && *end != '\n') { 430 pr_err("invalid IPv6 address at: <%c>\n", *end); 431 return -EINVAL; 432 } 433 nt->np.ipv6 = true; 434 } else 435 return -EINVAL; 436 } else { 437 if (!nt->np.ipv6) { 438 nt->np.local_ip.ip = in_aton(buf); 439 } else 440 return -EINVAL; 441 } 442 443 return strnlen(buf, count); 444} 445 446static ssize_t store_remote_ip(struct netconsole_target *nt, 447 const char *buf, 448 size_t count) 449{ 450 if (nt->enabled) { 451 pr_err("target (%s) is enabled, disable to update parameters\n", 452 config_item_name(&nt->item)); 453 return -EINVAL; 454 } 455 456 if (strnchr(buf, count, ':')) { 457 const char *end; 458 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) { 459 if (*end && *end != '\n') { 460 pr_err("invalid IPv6 address at: <%c>\n", *end); 461 return -EINVAL; 462 } 463 nt->np.ipv6 = true; 464 } else 465 return -EINVAL; 466 } else { 467 if (!nt->np.ipv6) { 468 nt->np.remote_ip.ip = in_aton(buf); 469 } else 470 return -EINVAL; 471 } 472 473 return strnlen(buf, count); 474} 475 476static ssize_t store_remote_mac(struct netconsole_target *nt, 477 const char *buf, 478 size_t count) 479{ 480 u8 remote_mac[ETH_ALEN]; 481 482 if (nt->enabled) { 483 pr_err("target (%s) is enabled, disable to update parameters\n", 484 config_item_name(&nt->item)); 485 return -EINVAL; 486 } 487 488 if (!mac_pton(buf, remote_mac)) 489 return -EINVAL; 490 if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n') 491 return -EINVAL; 492 memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN); 493 494 return strnlen(buf, count); 495} 496 497/* 498 * Attribute definitions for netconsole_target. 499 */ 500 501#define NETCONSOLE_TARGET_ATTR_RO(_name) \ 502static struct netconsole_target_attr netconsole_target_##_name = \ 503 __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL) 504 505#define NETCONSOLE_TARGET_ATTR_RW(_name) \ 506static struct netconsole_target_attr netconsole_target_##_name = \ 507 __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name) 508 509NETCONSOLE_TARGET_ATTR_RW(enabled); 510NETCONSOLE_TARGET_ATTR_RW(dev_name); 511NETCONSOLE_TARGET_ATTR_RW(local_port); 512NETCONSOLE_TARGET_ATTR_RW(remote_port); 513NETCONSOLE_TARGET_ATTR_RW(local_ip); 514NETCONSOLE_TARGET_ATTR_RW(remote_ip); 515NETCONSOLE_TARGET_ATTR_RO(local_mac); 516NETCONSOLE_TARGET_ATTR_RW(remote_mac); 517 518static struct configfs_attribute *netconsole_target_attrs[] = { 519 &netconsole_target_enabled.attr, 520 &netconsole_target_dev_name.attr, 521 &netconsole_target_local_port.attr, 522 &netconsole_target_remote_port.attr, 523 &netconsole_target_local_ip.attr, 524 &netconsole_target_remote_ip.attr, 525 &netconsole_target_local_mac.attr, 526 &netconsole_target_remote_mac.attr, 527 NULL, 528}; 529 530/* 531 * Item operations and type for netconsole_target. 532 */ 533 534static void netconsole_target_release(struct config_item *item) 535{ 536 kfree(to_target(item)); 537} 538 539static ssize_t netconsole_target_attr_show(struct config_item *item, 540 struct configfs_attribute *attr, 541 char *buf) 542{ 543 ssize_t ret = -EINVAL; 544 struct netconsole_target *nt = to_target(item); 545 struct netconsole_target_attr *na = 546 container_of(attr, struct netconsole_target_attr, attr); 547 548 if (na->show) 549 ret = na->show(nt, buf); 550 551 return ret; 552} 553 554static ssize_t netconsole_target_attr_store(struct config_item *item, 555 struct configfs_attribute *attr, 556 const char *buf, 557 size_t count) 558{ 559 ssize_t ret = -EINVAL; 560 struct netconsole_target *nt = to_target(item); 561 struct netconsole_target_attr *na = 562 container_of(attr, struct netconsole_target_attr, attr); 563 564 mutex_lock(&nt->mutex); 565 if (na->store) 566 ret = na->store(nt, buf, count); 567 mutex_unlock(&nt->mutex); 568 569 return ret; 570} 571 572static struct configfs_item_operations netconsole_target_item_ops = { 573 .release = netconsole_target_release, 574 .show_attribute = netconsole_target_attr_show, 575 .store_attribute = netconsole_target_attr_store, 576}; 577 578static struct config_item_type netconsole_target_type = { 579 .ct_attrs = netconsole_target_attrs, 580 .ct_item_ops = &netconsole_target_item_ops, 581 .ct_owner = THIS_MODULE, 582}; 583 584/* 585 * Group operations and type for netconsole_subsys. 586 */ 587 588static struct config_item *make_netconsole_target(struct config_group *group, 589 const char *name) 590{ 591 unsigned long flags; 592 struct netconsole_target *nt; 593 594 /* 595 * Allocate and initialize with defaults. 596 * Target is disabled at creation (enabled == 0). 597 */ 598 nt = kzalloc(sizeof(*nt), GFP_KERNEL); 599 if (!nt) 600 return ERR_PTR(-ENOMEM); 601 602 nt->np.name = "netconsole"; 603 strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ); 604 nt->np.local_port = 6665; 605 nt->np.remote_port = 6666; 606 mutex_init(&nt->mutex); 607 memset(nt->np.remote_mac, 0xff, ETH_ALEN); 608 609 /* Initialize the config_item member */ 610 config_item_init_type_name(&nt->item, name, &netconsole_target_type); 611 612 /* Adding, but it is disabled */ 613 spin_lock_irqsave(&target_list_lock, flags); 614 list_add(&nt->list, &target_list); 615 spin_unlock_irqrestore(&target_list_lock, flags); 616 617 return &nt->item; 618} 619 620static void drop_netconsole_target(struct config_group *group, 621 struct config_item *item) 622{ 623 unsigned long flags; 624 struct netconsole_target *nt = to_target(item); 625 626 spin_lock_irqsave(&target_list_lock, flags); 627 list_del(&nt->list); 628 spin_unlock_irqrestore(&target_list_lock, flags); 629 630 /* 631 * The target may have never been enabled, or was manually disabled 632 * before being removed so netpoll may have already been cleaned up. 633 */ 634 if (nt->enabled) 635 netpoll_cleanup(&nt->np); 636 637 config_item_put(&nt->item); 638} 639 640static struct configfs_group_operations netconsole_subsys_group_ops = { 641 .make_item = make_netconsole_target, 642 .drop_item = drop_netconsole_target, 643}; 644 645static struct config_item_type netconsole_subsys_type = { 646 .ct_group_ops = &netconsole_subsys_group_ops, 647 .ct_owner = THIS_MODULE, 648}; 649 650/* The netconsole configfs subsystem */ 651static struct configfs_subsystem netconsole_subsys = { 652 .su_group = { 653 .cg_item = { 654 .ci_namebuf = "netconsole", 655 .ci_type = &netconsole_subsys_type, 656 }, 657 }, 658}; 659 660#endif /* CONFIG_NETCONSOLE_DYNAMIC */ 661 662/* Handle network interface device notifications */ 663static int netconsole_netdev_event(struct notifier_block *this, 664 unsigned long event, void *ptr) 665{ 666 unsigned long flags; 667 struct netconsole_target *nt; 668 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 669 bool stopped = false; 670 671 if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER || 672 event == NETDEV_RELEASE || event == NETDEV_JOIN)) 673 goto done; 674 675 spin_lock_irqsave(&target_list_lock, flags); 676restart: 677 list_for_each_entry(nt, &target_list, list) { 678 netconsole_target_get(nt); 679 if (nt->np.dev == dev) { 680 switch (event) { 681 case NETDEV_CHANGENAME: 682 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ); 683 break; 684 case NETDEV_RELEASE: 685 case NETDEV_JOIN: 686 case NETDEV_UNREGISTER: 687 /* rtnl_lock already held 688 * we might sleep in __netpoll_cleanup() 689 */ 690 spin_unlock_irqrestore(&target_list_lock, flags); 691 692 __netpoll_cleanup(&nt->np); 693 694 spin_lock_irqsave(&target_list_lock, flags); 695 dev_put(nt->np.dev); 696 nt->np.dev = NULL; 697 nt->enabled = 0; 698 stopped = true; 699 netconsole_target_put(nt); 700 goto restart; 701 } 702 } 703 netconsole_target_put(nt); 704 } 705 spin_unlock_irqrestore(&target_list_lock, flags); 706 if (stopped) { 707 const char *msg = "had an event"; 708 switch (event) { 709 case NETDEV_UNREGISTER: 710 msg = "unregistered"; 711 break; 712 case NETDEV_RELEASE: 713 msg = "released slaves"; 714 break; 715 case NETDEV_JOIN: 716 msg = "is joining a master device"; 717 break; 718 } 719 pr_info("network logging stopped on interface %s as it %s\n", 720 dev->name, msg); 721 } 722 723done: 724 return NOTIFY_DONE; 725} 726 727static struct notifier_block netconsole_netdev_notifier = { 728 .notifier_call = netconsole_netdev_event, 729}; 730 731static void write_msg(struct console *con, const char *msg, unsigned int len) 732{ 733 int frag, left; 734 unsigned long flags; 735 struct netconsole_target *nt; 736 const char *tmp; 737 738 if (oops_only && !oops_in_progress) 739 return; 740 /* Avoid taking lock and disabling interrupts unnecessarily */ 741 if (list_empty(&target_list)) 742 return; 743 744 spin_lock_irqsave(&target_list_lock, flags); 745 list_for_each_entry(nt, &target_list, list) { 746 netconsole_target_get(nt); 747 if (nt->enabled && netif_running(nt->np.dev)) { 748 /* 749 * We nest this inside the for-each-target loop above 750 * so that we're able to get as much logging out to 751 * at least one target if we die inside here, instead 752 * of unnecessarily keeping all targets in lock-step. 753 */ 754 tmp = msg; 755 for (left = len; left;) { 756 frag = min(left, MAX_PRINT_CHUNK); 757 netpoll_send_udp(&nt->np, tmp, frag); 758 tmp += frag; 759 left -= frag; 760 } 761 } 762 netconsole_target_put(nt); 763 } 764 spin_unlock_irqrestore(&target_list_lock, flags); 765} 766 767static struct console netconsole = { 768 .name = "netcon", 769 .flags = CON_ENABLED, 770 .write = write_msg, 771}; 772 773static int __init init_netconsole(void) 774{ 775 int err; 776 struct netconsole_target *nt, *tmp; 777 unsigned long flags; 778 char *target_config; 779 char *input = config; 780 781 if (strnlen(input, MAX_PARAM_LENGTH)) { 782 while ((target_config = strsep(&input, ";"))) { 783 nt = alloc_param_target(target_config); 784 if (IS_ERR(nt)) { 785 err = PTR_ERR(nt); 786 goto fail; 787 } 788 /* Dump existing printks when we register */ 789 netconsole.flags |= CON_PRINTBUFFER; 790 791 spin_lock_irqsave(&target_list_lock, flags); 792 list_add(&nt->list, &target_list); 793 spin_unlock_irqrestore(&target_list_lock, flags); 794 } 795 } 796 797 err = register_netdevice_notifier(&netconsole_netdev_notifier); 798 if (err) 799 goto fail; 800 801 err = dynamic_netconsole_init(); 802 if (err) 803 goto undonotifier; 804 805 register_console(&netconsole); 806 pr_info("network logging started\n"); 807 808 return err; 809 810undonotifier: 811 unregister_netdevice_notifier(&netconsole_netdev_notifier); 812 813fail: 814 pr_err("cleaning up\n"); 815 816 /* 817 * Remove all targets and destroy them (only targets created 818 * from the boot/module option exist here). Skipping the list 819 * lock is safe here, and netpoll_cleanup() will sleep. 820 */ 821 list_for_each_entry_safe(nt, tmp, &target_list, list) { 822 list_del(&nt->list); 823 free_param_target(nt); 824 } 825 826 return err; 827} 828 829static void __exit cleanup_netconsole(void) 830{ 831 struct netconsole_target *nt, *tmp; 832 833 unregister_console(&netconsole); 834 dynamic_netconsole_exit(); 835 unregister_netdevice_notifier(&netconsole_netdev_notifier); 836 837 /* 838 * Targets created via configfs pin references on our module 839 * and would first be rmdir(2)'ed from userspace. We reach 840 * here only when they are already destroyed, and only those 841 * created from the boot/module option are left, so remove and 842 * destroy them. Skipping the list lock is safe here, and 843 * netpoll_cleanup() will sleep. 844 */ 845 list_for_each_entry_safe(nt, tmp, &target_list, list) { 846 list_del(&nt->list); 847 free_param_target(nt); 848 } 849} 850 851/* 852 * Use late_initcall to ensure netconsole is 853 * initialized after network device driver if built-in. 854 * 855 * late_initcall() and module_init() are identical if built as module. 856 */ 857late_initcall(init_netconsole); 858module_exit(cleanup_netconsole); 859