diff options
Diffstat (limited to 'lib/kobject_uevent.c')
-rw-r--r-- | lib/kobject_uevent.c | 424 |
1 files changed, 424 insertions, 0 deletions
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c new file mode 100644 index 00000000..6d40244e --- /dev/null +++ b/lib/kobject_uevent.c @@ -0,0 +1,424 @@ +/* + * kernel userspace event delivery + * + * Copyright (C) 2004 Red Hat, Inc. All rights reserved. + * Copyright (C) 2004 Novell, Inc. All rights reserved. + * Copyright (C) 2004 IBM, Inc. All rights reserved. + * + * Licensed under the GNU GPL v2. + * + * Authors: + * Robert Love <rml@novell.com> + * Kay Sievers <kay.sievers@vrfy.org> + * Arjan van de Ven <arjanv@redhat.com> + * Greg Kroah-Hartman <greg@kroah.com> + */ + +#include <linux/spinlock.h> +#include <linux/string.h> +#include <linux/kobject.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/user_namespace.h> +#include <linux/socket.h> +#include <linux/skbuff.h> +#include <linux/netlink.h> +#include <net/sock.h> +#include <net/net_namespace.h> + + +u64 uevent_seqnum; +char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; +#ifdef CONFIG_NET +struct uevent_sock { + struct list_head list; + struct sock *sk; +}; +static LIST_HEAD(uevent_sock_list); +#endif + +/* This lock protects uevent_seqnum and uevent_sock_list */ +static DEFINE_MUTEX(uevent_sock_mutex); + +/* the strings here must match the enum in include/linux/kobject.h */ +static const char *kobject_actions[] = { + [KOBJ_ADD] = "add", + [KOBJ_REMOVE] = "remove", + [KOBJ_CHANGE] = "change", + [KOBJ_MOVE] = "move", + [KOBJ_ONLINE] = "online", + [KOBJ_OFFLINE] = "offline", +}; + +/** + * kobject_action_type - translate action string to numeric type + * + * @buf: buffer containing the action string, newline is ignored + * @len: length of buffer + * @type: pointer to the location to store the action type + * + * Returns 0 if the action string was recognized. + */ +int kobject_action_type(const char *buf, size_t count, + enum kobject_action *type) +{ + enum kobject_action action; + int ret = -EINVAL; + + if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) + count--; + + if (!count) + goto out; + + for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { + if (strncmp(kobject_actions[action], buf, count) != 0) + continue; + if (kobject_actions[action][count] != '\0') + continue; + *type = action; + ret = 0; + break; + } +out: + return ret; +} + +#ifdef CONFIG_NET +static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) +{ + struct kobject *kobj = data; + const struct kobj_ns_type_operations *ops; + + ops = kobj_ns_ops(kobj); + if (ops) { + const void *sock_ns, *ns; + ns = kobj->ktype->namespace(kobj); + sock_ns = ops->netlink_ns(dsk); + return sock_ns != ns; + } + + return 0; +} +#endif + +static int kobj_usermode_filter(struct kobject *kobj) +{ + const struct kobj_ns_type_operations *ops; + + ops = kobj_ns_ops(kobj); + if (ops) { + const void *init_ns, *ns; + ns = kobj->ktype->namespace(kobj); + init_ns = ops->initial_ns(); + return ns != init_ns; + } + + return 0; +} + +/** + * kobject_uevent_env - send an uevent with environmental data + * + * @action: action that is happening + * @kobj: struct kobject that the action is happening to + * @envp_ext: pointer to environmental data + * + * Returns 0 if kobject_uevent_env() is completed with success or the + * corresponding error when it fails. + */ +int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, + char *envp_ext[]) +{ + struct kobj_uevent_env *env; + const char *action_string = kobject_actions[action]; + const char *devpath = NULL; + const char *subsystem; + struct kobject *top_kobj; + struct kset *kset; + const struct kset_uevent_ops *uevent_ops; + int i = 0; + int retval = 0; +#ifdef CONFIG_NET + struct uevent_sock *ue_sk; +#endif + + pr_debug("kobject: '%s' (%p): %s\n", + kobject_name(kobj), kobj, __func__); + + /* search the kset we belong to */ + top_kobj = kobj; + while (!top_kobj->kset && top_kobj->parent) + top_kobj = top_kobj->parent; + + if (!top_kobj->kset) { + pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " + "without kset!\n", kobject_name(kobj), kobj, + __func__); + return -EINVAL; + } + + kset = top_kobj->kset; + uevent_ops = kset->uevent_ops; + + /* skip the event, if uevent_suppress is set*/ + if (kobj->uevent_suppress) { + pr_debug("kobject: '%s' (%p): %s: uevent_suppress " + "caused the event to drop!\n", + kobject_name(kobj), kobj, __func__); + return 0; + } + /* skip the event, if the filter returns zero. */ + if (uevent_ops && uevent_ops->filter) + if (!uevent_ops->filter(kset, kobj)) { + pr_debug("kobject: '%s' (%p): %s: filter function " + "caused the event to drop!\n", + kobject_name(kobj), kobj, __func__); + return 0; + } + + /* originating subsystem */ + if (uevent_ops && uevent_ops->name) + subsystem = uevent_ops->name(kset, kobj); + else + subsystem = kobject_name(&kset->kobj); + if (!subsystem) { + pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " + "event to drop!\n", kobject_name(kobj), kobj, + __func__); + return 0; + } + + /* environment buffer */ + env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); + if (!env) + return -ENOMEM; + + /* complete object path */ + devpath = kobject_get_path(kobj, GFP_KERNEL); + if (!devpath) { + retval = -ENOENT; + goto exit; + } + + /* default keys */ + retval = add_uevent_var(env, "ACTION=%s", action_string); + if (retval) + goto exit; + retval = add_uevent_var(env, "DEVPATH=%s", devpath); + if (retval) + goto exit; + retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); + if (retval) + goto exit; + + /* keys passed in from the caller */ + if (envp_ext) { + for (i = 0; envp_ext[i]; i++) { + retval = add_uevent_var(env, "%s", envp_ext[i]); + if (retval) + goto exit; + } + } + + /* let the kset specific function add its stuff */ + if (uevent_ops && uevent_ops->uevent) { + retval = uevent_ops->uevent(kset, kobj, env); + if (retval) { + pr_debug("kobject: '%s' (%p): %s: uevent() returned " + "%d\n", kobject_name(kobj), kobj, + __func__, retval); + goto exit; + } + } + + /* + * Mark "add" and "remove" events in the object to ensure proper + * events to userspace during automatic cleanup. If the object did + * send an "add" event, "remove" will automatically generated by + * the core, if not already done by the caller. + */ + if (action == KOBJ_ADD) + kobj->state_add_uevent_sent = 1; + else if (action == KOBJ_REMOVE) + kobj->state_remove_uevent_sent = 1; + + mutex_lock(&uevent_sock_mutex); + /* we will send an event, so request a new sequence number */ + retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum); + if (retval) { + mutex_unlock(&uevent_sock_mutex); + goto exit; + } + +#if defined(CONFIG_NET) + /* send netlink message */ + list_for_each_entry(ue_sk, &uevent_sock_list, list) { + struct sock *uevent_sock = ue_sk->sk; + struct sk_buff *skb; + size_t len; + + /* allocate message with the maximum possible size */ + len = strlen(action_string) + strlen(devpath) + 2; + skb = alloc_skb(len + env->buflen, GFP_KERNEL); + if (skb) { + char *scratch; + + /* add header */ + scratch = skb_put(skb, len); + sprintf(scratch, "%s@%s", action_string, devpath); + + /* copy keys to our continuous event payload buffer */ + for (i = 0; i < env->envp_idx; i++) { + len = strlen(env->envp[i]) + 1; + scratch = skb_put(skb, len); + strcpy(scratch, env->envp[i]); + } + + NETLINK_CB(skb).dst_group = 1; + retval = netlink_broadcast_filtered(uevent_sock, skb, + 0, 1, GFP_KERNEL, + kobj_bcast_filter, + kobj); + /* ENOBUFS should be handled in userspace */ + if (retval == -ENOBUFS || retval == -ESRCH) + retval = 0; + } else + retval = -ENOMEM; + } +#endif + mutex_unlock(&uevent_sock_mutex); + + /* call uevent_helper, usually only enabled during early boot */ + if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { + char *argv [3]; + + argv [0] = uevent_helper; + argv [1] = (char *)subsystem; + argv [2] = NULL; + retval = add_uevent_var(env, "HOME=/"); + if (retval) + goto exit; + retval = add_uevent_var(env, + "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); + if (retval) + goto exit; + + retval = call_usermodehelper(argv[0], argv, + env->envp, UMH_WAIT_EXEC); + } + +exit: + kfree(devpath); + kfree(env); + return retval; +} +EXPORT_SYMBOL_GPL(kobject_uevent_env); + +/** + * kobject_uevent - notify userspace by sending an uevent + * + * @action: action that is happening + * @kobj: struct kobject that the action is happening to + * + * Returns 0 if kobject_uevent() is completed with success or the + * corresponding error when it fails. + */ +int kobject_uevent(struct kobject *kobj, enum kobject_action action) +{ + return kobject_uevent_env(kobj, action, NULL); +} +EXPORT_SYMBOL_GPL(kobject_uevent); + +/** + * add_uevent_var - add key value string to the environment buffer + * @env: environment buffer structure + * @format: printf format for the key=value pair + * + * Returns 0 if environment variable was added successfully or -ENOMEM + * if no space was available. + */ +int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) +{ + va_list args; + int len; + + if (env->envp_idx >= ARRAY_SIZE(env->envp)) { + WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); + return -ENOMEM; + } + + va_start(args, format); + len = vsnprintf(&env->buf[env->buflen], + sizeof(env->buf) - env->buflen, + format, args); + va_end(args); + + if (len >= (sizeof(env->buf) - env->buflen)) { + WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); + return -ENOMEM; + } + + env->envp[env->envp_idx++] = &env->buf[env->buflen]; + env->buflen += len + 1; + return 0; +} +EXPORT_SYMBOL_GPL(add_uevent_var); + +#if defined(CONFIG_NET) +static int uevent_net_init(struct net *net) +{ + struct uevent_sock *ue_sk; + + ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); + if (!ue_sk) + return -ENOMEM; + + ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, + 1, NULL, NULL, THIS_MODULE); + if (!ue_sk->sk) { + printk(KERN_ERR + "kobject_uevent: unable to create netlink socket!\n"); + kfree(ue_sk); + return -ENODEV; + } + mutex_lock(&uevent_sock_mutex); + list_add_tail(&ue_sk->list, &uevent_sock_list); + mutex_unlock(&uevent_sock_mutex); + return 0; +} + +static void uevent_net_exit(struct net *net) +{ + struct uevent_sock *ue_sk; + + mutex_lock(&uevent_sock_mutex); + list_for_each_entry(ue_sk, &uevent_sock_list, list) { + if (sock_net(ue_sk->sk) == net) + goto found; + } + mutex_unlock(&uevent_sock_mutex); + return; + +found: + list_del(&ue_sk->list); + mutex_unlock(&uevent_sock_mutex); + + netlink_kernel_release(ue_sk->sk); + kfree(ue_sk); +} + +static struct pernet_operations uevent_net_ops = { + .init = uevent_net_init, + .exit = uevent_net_exit, +}; + +static int __init kobject_uevent_init(void) +{ + netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV); + return register_pernet_subsys(&uevent_net_ops); +} + + +postcore_initcall(kobject_uevent_init); +#endif |