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netconsole.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* linux/drivers/net/netconsole.c
*
* Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
*
* This file contains the implementation of an IRQ-safe, crash-safe
* kernel console implementation that outputs kernel messages to the
* network.
*
* Modification history:
*
* 2001-09-17 started by Ingo Molnar.
* 2003-08-11 2.6 port by Matt Mackall
* simplified options
* generic card hooks
* works non-modular
* 2003-09-07 rewritten with netpoll api
*/
/****************************************************************
*
****************************************************************/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/console.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/netpoll.h>
#include <linux/inet.h>
#include <linux/configfs.h>
#include <linux/etherdevice.h>
#include <linux/utsname.h>
MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
MODULE_DESCRIPTION("Console driver for network interfaces");
MODULE_LICENSE("GPL");
#define MAX_PARAM_LENGTH 256
#define MAX_USERDATA_ENTRY_LENGTH 256
#define MAX_USERDATA_VALUE_LENGTH 200
/* The number 3 comes from userdata entry format characters (' ', '=', '\n') */
#define MAX_USERDATA_NAME_LENGTH (MAX_USERDATA_ENTRY_LENGTH - \
MAX_USERDATA_VALUE_LENGTH - 3)
#define MAX_USERDATA_ITEMS 16
#define MAX_PRINT_CHUNK 1000
static char config[MAX_PARAM_LENGTH];
module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
static bool oops_only;
module_param(oops_only, bool, 0600);
MODULE_PARM_DESC(oops_only, "Only log oops messages");
#define NETCONSOLE_PARAM_TARGET_PREFIX "cmdline"
#ifndef MODULE
static int __init option_setup(char *opt)
{
strscpy(config, opt, MAX_PARAM_LENGTH);
return 1;
}
__setup("netconsole=", option_setup);
#endif /* MODULE */
/* Linked list of all configured targets */
static LIST_HEAD(target_list);
/* This needs to be a spinlock because write_msg() cannot sleep */
static DEFINE_SPINLOCK(target_list_lock);
/*
* Console driver for extended netconsoles. Registered on the first use to
* avoid unnecessarily enabling ext message formatting.
*/
static struct console netconsole_ext;
/**
* struct netconsole_target - Represents a configured netconsole target.
* @list: Links this target into the target_list.
* @group: Links us into the configfs subsystem hierarchy.
* @userdata_group: Links to the userdata configfs hierarchy
* @userdata_complete: Cached, formatted string of append
* @userdata_length: String length of userdata_complete
* @enabled: On / off knob to enable / disable target.
* Visible from userspace (read-write).
* We maintain a strict 1:1 correspondence between this and
* whether the corresponding netpoll is active or inactive.
* Also, other parameters of a target may be modified at
* runtime only when it is disabled (enabled == 0).
* @extended: Denotes whether console is extended or not.
* @release: Denotes whether kernel release version should be prepended
* to the message. Depends on extended console.
* @np: The netpoll structure for this target.
* Contains the other userspace visible parameters:
* dev_name (read-write)
* local_port (read-write)
* remote_port (read-write)
* local_ip (read-write)
* remote_ip (read-write)
* local_mac (read-only)
* remote_mac (read-write)
*/
struct netconsole_target {
struct list_head list;
#ifdef CONFIG_NETCONSOLE_DYNAMIC
struct config_group group;
struct config_group userdata_group;
char userdata_complete[MAX_USERDATA_ENTRY_LENGTH * MAX_USERDATA_ITEMS];
size_t userdata_length;
#endif
bool enabled;
bool extended;
bool release;
struct netpoll np;
};
#ifdef CONFIG_NETCONSOLE_DYNAMIC
static struct configfs_subsystem netconsole_subsys;
static DEFINE_MUTEX(dynamic_netconsole_mutex);
static int __init dynamic_netconsole_init(void)
{
config_group_init(&netconsole_subsys.su_group);
mutex_init(&netconsole_subsys.su_mutex);
return configfs_register_subsystem(&netconsole_subsys);
}
static void __exit dynamic_netconsole_exit(void)
{
configfs_unregister_subsystem(&netconsole_subsys);
}
/*
* Targets that were created by parsing the boot/module option string
* do not exist in the configfs hierarchy (and have NULL names) and will
* never go away, so make these a no-op for them.
*/
static void netconsole_target_get(struct netconsole_target *nt)
{
if (config_item_name(&nt->group.cg_item))
config_group_get(&nt->group);
}
static void netconsole_target_put(struct netconsole_target *nt)
{
if (config_item_name(&nt->group.cg_item))
config_group_put(&nt->group);
}
#else /* !CONFIG_NETCONSOLE_DYNAMIC */
static int __init dynamic_netconsole_init(void)
{
return 0;
}
static void __exit dynamic_netconsole_exit(void)
{
}
/*
* No danger of targets going away from under us when dynamic
* reconfigurability is off.
*/
static void netconsole_target_get(struct netconsole_target *nt)
{
}
static void netconsole_target_put(struct netconsole_target *nt)
{
}
static void populate_configfs_item(struct netconsole_target *nt,
int cmdline_count)
{
}
#endif /* CONFIG_NETCONSOLE_DYNAMIC */
/* Allocate and initialize with defaults.
* Note that these targets get their config_item fields zeroed-out.
*/
static struct netconsole_target *alloc_and_init(void)
{
struct netconsole_target *nt;
nt = kzalloc(sizeof(*nt), GFP_KERNEL);
if (!nt)
return nt;
if (IS_ENABLED(CONFIG_NETCONSOLE_EXTENDED_LOG))
nt->extended = true;
if (IS_ENABLED(CONFIG_NETCONSOLE_PREPEND_RELEASE))
nt->release = true;
nt->np.name = "netconsole";
strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
nt->np.local_port = 6665;
nt->np.remote_port = 6666;
eth_broadcast_addr(nt->np.remote_mac);
return nt;
}
#ifdef CONFIG_NETCONSOLE_DYNAMIC
/*
* Our subsystem hierarchy is:
*
* /sys/kernel/config/netconsole/
* |
* <target>/
* | enabled
* | release
* | dev_name
* | local_port
* | remote_port
* | local_ip
* | remote_ip
* | local_mac
* | remote_mac
* | userdata/
* | <key>/
* | value
* | ...
* |
* <target>/...
*/
static struct netconsole_target *to_target(struct config_item *item)
{
struct config_group *cfg_group;
cfg_group = to_config_group(item);
if (!cfg_group)
return NULL;
return container_of(to_config_group(item),
struct netconsole_target, group);
}
/* Get rid of possible trailing newline, returning the new length */
static void trim_newline(char *s, size_t maxlen)
{
size_t len;
len = strnlen(s, maxlen);
if (s[len - 1] == '\n')
s[len - 1] = '\0';
}
/*
* Attribute operations for netconsole_target.
*/
static ssize_t enabled_show(struct config_item *item, char *buf)
{
return sysfs_emit(buf, "%d\n", to_target(item)->enabled);
}
static ssize_t extended_show(struct config_item *item, char *buf)
{
return sysfs_emit(buf, "%d\n", to_target(item)->extended);
}
static ssize_t release_show(struct config_item *item, char *buf)
{
return sysfs_emit(buf, "%d\n", to_target(item)->release);
}
static ssize_t dev_name_show(struct config_item *item, char *buf)
{
return sysfs_emit(buf, "%s\n", to_target(item)->np.dev_name);
}
static ssize_t local_port_show(struct config_item *item, char *buf)
{
return sysfs_emit(buf, "%d\n", to_target(item)->np.local_port);
}
static ssize_t remote_port_show(struct config_item *item, char *buf)
{
return sysfs_emit(buf, "%d\n", to_target(item)->np.remote_port);
}
static ssize_t local_ip_show(struct config_item *item, char *buf)
{
struct netconsole_target *nt = to_target(item);
if (nt->np.ipv6)
return sysfs_emit(buf, "%pI6c\n", &nt->np.local_ip.in6);
else
return sysfs_emit(buf, "%pI4\n", &nt->np.local_ip);
}
static ssize_t remote_ip_show(struct config_item *item, char *buf)
{
struct netconsole_target *nt = to_target(item);
if (nt->np.ipv6)
return sysfs_emit(buf, "%pI6c\n", &nt->np.remote_ip.in6);
else
return sysfs_emit(buf, "%pI4\n", &nt->np.remote_ip);
}
static ssize_t local_mac_show(struct config_item *item, char *buf)
{
struct net_device *dev = to_target(item)->np.dev;
static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
return sysfs_emit(buf, "%pM\n", dev ? dev->dev_addr : bcast);
}
static ssize_t remote_mac_show(struct config_item *item, char *buf)
{
return sysfs_emit(buf, "%pM\n", to_target(item)->np.remote_mac);
}
/*
* This one is special -- targets created through the configfs interface
* are not enabled (and the corresponding netpoll activated) by default.
* The user is expected to set the desired parameters first (which
* would enable him to dynamically add new netpoll targets for new
* network interfaces as and when they come up).
*/
static ssize_t enabled_store(struct config_item *item,
const char *buf, size_t count)
{
struct netconsole_target *nt = to_target(item);
unsigned long flags;
bool enabled;
int err;
mutex_lock(&dynamic_netconsole_mutex);
err = kstrtobool(buf, &enabled);
if (err)
goto out_unlock;
err = -EINVAL;
if (enabled == nt->enabled) {
pr_info("network logging has already %s\n",
nt->enabled ? "started" : "stopped");
goto out_unlock;
}
if (enabled) { /* true */
if (nt->release && !nt->extended) {
pr_err("Not enabling netconsole. Release feature requires extended log message");
goto out_unlock;
}
if (nt->extended && !console_is_registered(&netconsole_ext))
register_console(&netconsole_ext);
/*
* Skip netpoll_parse_options() -- all the attributes are
* already configured via configfs. Just print them out.
*/
netpoll_print_options(&nt->np);
err = netpoll_setup(&nt->np);
if (err)
goto out_unlock;
nt->enabled = true;
pr_info("network logging started\n");
} else { /* false */
/* We need to disable the netconsole before cleaning it up
* otherwise we might end up in write_msg() with
* nt->np.dev == NULL and nt->enabled == true
*/
spin_lock_irqsave(&target_list_lock, flags);
nt->enabled = false;
spin_unlock_irqrestore(&target_list_lock, flags);
netpoll_cleanup(&nt->np);
}
mutex_unlock(&dynamic_netconsole_mutex);
return strnlen(buf, count);
out_unlock:
mutex_unlock(&dynamic_netconsole_mutex);
return err;
}
static ssize_t release_store(struct config_item *item, const char *buf,
size_t count)
{
struct netconsole_target *nt = to_target(item);
bool release;
int err;
mutex_lock(&dynamic_netconsole_mutex);
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->group.cg_item));
err = -EINVAL;
goto out_unlock;
}
err = kstrtobool(buf, &release);
if (err)
goto out_unlock;
nt->release = release;
mutex_unlock(&dynamic_netconsole_mutex);
return strnlen(buf, count);
out_unlock:
mutex_unlock(&dynamic_netconsole_mutex);
return err;
}
static ssize_t extended_store(struct config_item *item, const char *buf,
size_t count)
{
struct netconsole_target *nt = to_target(item);
bool extended;
int err;
mutex_lock(&dynamic_netconsole_mutex);
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->group.cg_item));
err = -EINVAL;
goto out_unlock;
}
err = kstrtobool(buf, &extended);
if (err)
goto out_unlock;
nt->extended = extended;
mutex_unlock(&dynamic_netconsole_mutex);
return strnlen(buf, count);
out_unlock:
mutex_unlock(&dynamic_netconsole_mutex);
return err;
}
static ssize_t dev_name_store(struct config_item *item, const char *buf,
size_t count)
{
struct netconsole_target *nt = to_target(item);
mutex_lock(&dynamic_netconsole_mutex);
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->group.cg_item));
mutex_unlock(&dynamic_netconsole_mutex);
return -EINVAL;
}
strscpy(nt->np.dev_name, buf, IFNAMSIZ);
trim_newline(nt->np.dev_name, IFNAMSIZ);
mutex_unlock(&dynamic_netconsole_mutex);
return strnlen(buf, count);
}
static ssize_t local_port_store(struct config_item *item, const char *buf,
size_t count)
{
struct netconsole_target *nt = to_target(item);
int rv = -EINVAL;
mutex_lock(&dynamic_netconsole_mutex);
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->group.cg_item));
goto out_unlock;
}
rv = kstrtou16(buf, 10, &nt->np.local_port);
if (rv < 0)
goto out_unlock;
mutex_unlock(&dynamic_netconsole_mutex);
return strnlen(buf, count);
out_unlock:
mutex_unlock(&dynamic_netconsole_mutex);
return rv;
}
static ssize_t remote_port_store(struct config_item *item,
const char *buf, size_t count)
{
struct netconsole_target *nt = to_target(item);
int rv = -EINVAL;
mutex_lock(&dynamic_netconsole_mutex);
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->group.cg_item));
goto out_unlock;
}
rv = kstrtou16(buf, 10, &nt->np.remote_port);
if (rv < 0)
goto out_unlock;
mutex_unlock(&dynamic_netconsole_mutex);
return strnlen(buf, count);
out_unlock:
mutex_unlock(&dynamic_netconsole_mutex);
return rv;
}
static ssize_t local_ip_store(struct config_item *item, const char *buf,
size_t count)
{
struct netconsole_target *nt = to_target(item);
mutex_lock(&dynamic_netconsole_mutex);
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->group.cg_item));
goto out_unlock;
}
if (strnchr(buf, count, ':')) {
const char *end;
if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
if (*end && *end != '\n') {
pr_err("invalid IPv6 address at: <%c>\n", *end);
goto out_unlock;
}
nt->np.ipv6 = true;
} else
goto out_unlock;
} else {
if (!nt->np.ipv6)
nt->np.local_ip.ip = in_aton(buf);
else
goto out_unlock;
}
mutex_unlock(&dynamic_netconsole_mutex);
return strnlen(buf, count);
out_unlock:
mutex_unlock(&dynamic_netconsole_mutex);
return -EINVAL;
}
static ssize_t remote_ip_store(struct config_item *item, const char *buf,
size_t count)
{
struct netconsole_target *nt = to_target(item);
mutex_lock(&dynamic_netconsole_mutex);
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->group.cg_item));
goto out_unlock;
}
if (strnchr(buf, count, ':')) {
const char *end;
if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
if (*end && *end != '\n') {
pr_err("invalid IPv6 address at: <%c>\n", *end);
goto out_unlock;
}
nt->np.ipv6 = true;
} else
goto out_unlock;
} else {
if (!nt->np.ipv6)
nt->np.remote_ip.ip = in_aton(buf);
else
goto out_unlock;
}
mutex_unlock(&dynamic_netconsole_mutex);
return strnlen(buf, count);
out_unlock:
mutex_unlock(&dynamic_netconsole_mutex);
return -EINVAL;
}
static ssize_t remote_mac_store(struct config_item *item, const char *buf,
size_t count)
{
struct netconsole_target *nt = to_target(item);
u8 remote_mac[ETH_ALEN];
mutex_lock(&dynamic_netconsole_mutex);
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->group.cg_item));
goto out_unlock;
}
if (!mac_pton(buf, remote_mac))
goto out_unlock;
if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
goto out_unlock;
memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
mutex_unlock(&dynamic_netconsole_mutex);
return strnlen(buf, count);
out_unlock:
mutex_unlock(&dynamic_netconsole_mutex);
return -EINVAL;
}
struct userdatum {
struct config_item item;
char value[MAX_USERDATA_VALUE_LENGTH];
};
static struct userdatum *to_userdatum(struct config_item *item)
{
return container_of(item, struct userdatum, item);
}
struct userdata {
struct config_group group;
};
static struct userdata *to_userdata(struct config_item *item)
{
return container_of(to_config_group(item), struct userdata, group);
}
static struct netconsole_target *userdata_to_target(struct userdata *ud)
{
struct config_group *netconsole_group;
netconsole_group = to_config_group(ud->group.cg_item.ci_parent);
return to_target(&netconsole_group->cg_item);
}
static ssize_t userdatum_value_show(struct config_item *item, char *buf)
{
return sysfs_emit(buf, "%s\n", &(to_userdatum(item)->value[0]));
}
static void update_userdata(struct netconsole_target *nt)
{
int complete_idx = 0, child_count = 0;
struct list_head *entry;
/* Clear the current string in case the last userdatum was deleted */
nt->userdata_length = 0;
nt->userdata_complete[0] = 0;
list_for_each(entry, &nt->userdata_group.cg_children) {
struct userdatum *udm_item;
struct config_item *item;
if (child_count >= MAX_USERDATA_ITEMS)
break;
child_count++;
item = container_of(entry, struct config_item, ci_entry);
udm_item = to_userdatum(item);
/* Skip userdata with no value set */
if (strnlen(udm_item->value, MAX_USERDATA_VALUE_LENGTH) == 0)
continue;
/* This doesn't overflow userdata_complete since it will write
* one entry length (1/MAX_USERDATA_ITEMS long), entry count is
* checked to not exceed MAX items with child_count above
*/
complete_idx += scnprintf(&nt->userdata_complete[complete_idx],
MAX_USERDATA_ENTRY_LENGTH, " %s=%s\n",
item->ci_name, udm_item->value);
}
nt->userdata_length = strnlen(nt->userdata_complete,
sizeof(nt->userdata_complete));
}
static ssize_t userdatum_value_store(struct config_item *item, const char *buf,
size_t count)
{
struct userdatum *udm = to_userdatum(item);
struct netconsole_target *nt;
struct userdata *ud;
int ret;
if (count > MAX_USERDATA_VALUE_LENGTH)
return -EMSGSIZE;
mutex_lock(&dynamic_netconsole_mutex);
ret = strscpy(udm->value, buf, sizeof(udm->value));
if (ret < 0)
goto out_unlock;
trim_newline(udm->value, sizeof(udm->value));
ud = to_userdata(item->ci_parent);
nt = userdata_to_target(ud);
update_userdata(nt);
mutex_unlock(&dynamic_netconsole_mutex);
return count;
out_unlock:
mutex_unlock(&dynamic_netconsole_mutex);
return ret;
}
CONFIGFS_ATTR(userdatum_, value);
static struct configfs_attribute *userdatum_attrs[] = {
&userdatum_attr_value,
NULL,
};
static void userdatum_release(struct config_item *item)
{
kfree(to_userdatum(item));
}
static struct configfs_item_operations userdatum_ops = {
.release = userdatum_release,
};
static const struct config_item_type userdatum_type = {
.ct_item_ops = &userdatum_ops,
.ct_attrs = userdatum_attrs,
.ct_owner = THIS_MODULE,
};
static struct config_item *userdatum_make_item(struct config_group *group,
const char *name)
{
struct netconsole_target *nt;
struct userdatum *udm;
struct userdata *ud;
size_t child_count;
if (strlen(name) > MAX_USERDATA_NAME_LENGTH)
return ERR_PTR(-ENAMETOOLONG);
ud = to_userdata(&group->cg_item);
nt = userdata_to_target(ud);
child_count = list_count_nodes(&nt->userdata_group.cg_children);
if (child_count >= MAX_USERDATA_ITEMS)
return ERR_PTR(-ENOSPC);
udm = kzalloc(sizeof(*udm), GFP_KERNEL);
if (!udm)
return ERR_PTR(-ENOMEM);
config_item_init_type_name(&udm->item, name, &userdatum_type);
return &udm->item;
}
static void userdatum_drop(struct config_group *group, struct config_item *item)
{
struct netconsole_target *nt;
struct userdata *ud;
ud = to_userdata(&group->cg_item);
nt = userdata_to_target(ud);
mutex_lock(&dynamic_netconsole_mutex);
update_userdata(nt);
config_item_put(item);
mutex_unlock(&dynamic_netconsole_mutex);
}
static struct configfs_attribute *userdata_attrs[] = {
NULL,
};
static struct configfs_group_operations userdata_ops = {
.make_item = userdatum_make_item,
.drop_item = userdatum_drop,
};
static struct config_item_type userdata_type = {
.ct_item_ops = &userdatum_ops,
.ct_group_ops = &userdata_ops,
.ct_attrs = userdata_attrs,
.ct_owner = THIS_MODULE,
};
CONFIGFS_ATTR(, enabled);
CONFIGFS_ATTR(, extended);
CONFIGFS_ATTR(, dev_name);
CONFIGFS_ATTR(, local_port);
CONFIGFS_ATTR(, remote_port);
CONFIGFS_ATTR(, local_ip);
CONFIGFS_ATTR(, remote_ip);
CONFIGFS_ATTR_RO(, local_mac);
CONFIGFS_ATTR(, remote_mac);
CONFIGFS_ATTR(, release);
static struct configfs_attribute *netconsole_target_attrs[] = {
&attr_enabled,
&attr_extended,
&attr_release,
&attr_dev_name,
&attr_local_port,
&attr_remote_port,
&attr_local_ip,
&attr_remote_ip,
&attr_local_mac,
&attr_remote_mac,
NULL,
};
/*
* Item operations and type for netconsole_target.
*/
static void netconsole_target_release(struct config_item *item)
{
kfree(to_target(item));
}
static struct configfs_item_operations netconsole_target_item_ops = {
.release = netconsole_target_release,
};
static const struct config_item_type netconsole_target_type = {
.ct_attrs = netconsole_target_attrs,
.ct_item_ops = &netconsole_target_item_ops,
.ct_owner = THIS_MODULE,
};
static void init_target_config_group(struct netconsole_target *nt,
const char *name)
{
config_group_init_type_name(&nt->group, name, &netconsole_target_type);
config_group_init_type_name(&nt->userdata_group, "userdata",
&userdata_type);
configfs_add_default_group(&nt->userdata_group, &nt->group);
}
static struct netconsole_target *find_cmdline_target(const char *name)
{
struct netconsole_target *nt, *ret = NULL;
unsigned long flags;
spin_lock_irqsave(&target_list_lock, flags);
list_for_each_entry(nt, &target_list, list) {
if (!strcmp(nt->group.cg_item.ci_name, name)) {
ret = nt;
break;
}
}
spin_unlock_irqrestore(&target_list_lock, flags);
return ret;
}
/*
* Group operations and type for netconsole_subsys.
*/
static struct config_group *make_netconsole_target(struct config_group *group,
const char *name)
{
struct netconsole_target *nt;
unsigned long flags;
/* Checking if a target by this name was created at boot time. If so,
* attach a configfs entry to that target. This enables dynamic
* control.
*/
if (!strncmp(name, NETCONSOLE_PARAM_TARGET_PREFIX,
strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) {
nt = find_cmdline_target(name);
if (nt) {
init_target_config_group(nt, name);
return &nt->group;
}
}
nt = alloc_and_init();
if (!nt)
return ERR_PTR(-ENOMEM);
/* Initialize the config_group member */
init_target_config_group(nt, name);
/* Adding, but it is disabled */
spin_lock_irqsave(&target_list_lock, flags);
list_add(&nt->list, &target_list);
spin_unlock_irqrestore(&target_list_lock, flags);
return &nt->group;
}
static void drop_netconsole_target(struct config_group *group,
struct config_item *item)
{
unsigned long flags;
struct netconsole_target *nt = to_target(item);
spin_lock_irqsave(&target_list_lock, flags);
list_del(&nt->list);
spin_unlock_irqrestore(&target_list_lock, flags);
/*
* The target may have never been enabled, or was manually disabled
* before being removed so netpoll may have already been cleaned up.
*/
if (nt->enabled)
netpoll_cleanup(&nt->np);
config_item_put(&nt->group.cg_item);
}
static struct configfs_group_operations netconsole_subsys_group_ops = {
.make_group = make_netconsole_target,
.drop_item = drop_netconsole_target,
};
static const struct config_item_type netconsole_subsys_type = {
.ct_group_ops = &netconsole_subsys_group_ops,
.ct_owner = THIS_MODULE,
};
/* The netconsole configfs subsystem */
static struct configfs_subsystem netconsole_subsys = {
.su_group = {
.cg_item = {
.ci_namebuf = "netconsole",
.ci_type = &netconsole_subsys_type,
},
},
};
static void populate_configfs_item(struct netconsole_target *nt,
int cmdline_count)
{
char target_name[16];
snprintf(target_name, sizeof(target_name), "%s%d",
NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count);
init_target_config_group(nt, target_name);
}
#endif /* CONFIG_NETCONSOLE_DYNAMIC */
/* Handle network interface device notifications */
static int netconsole_netdev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
unsigned long flags;
struct netconsole_target *nt;
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
bool stopped = false;
if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
event == NETDEV_RELEASE || event == NETDEV_JOIN))
goto done;
spin_lock_irqsave(&target_list_lock, flags);
restart:
list_for_each_entry(nt, &target_list, list) {
netconsole_target_get(nt);
if (nt->np.dev == dev) {
switch (event) {
case NETDEV_CHANGENAME:
strscpy(nt->np.dev_name, dev->name, IFNAMSIZ);
break;
case NETDEV_RELEASE:
case NETDEV_JOIN:
case NETDEV_UNREGISTER:
/* rtnl_lock already held
* we might sleep in __netpoll_cleanup()
*/
nt->enabled = false;
spin_unlock_irqrestore(&target_list_lock, flags);
__netpoll_cleanup(&nt->np);
spin_lock_irqsave(&target_list_lock, flags);
netdev_put(nt->np.dev, &nt->np.dev_tracker);
nt->np.dev = NULL;
stopped = true;
netconsole_target_put(nt);
goto restart;
}
}
netconsole_target_put(nt);
}
spin_unlock_irqrestore(&target_list_lock, flags);
if (stopped) {
const char *msg = "had an event";
switch (event) {
case NETDEV_UNREGISTER:
msg = "unregistered";
break;
case NETDEV_RELEASE:
msg = "released slaves";