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lib/kobject_uevent.c
11.4 KB
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/* * 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> |
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#include <linux/string.h> #include <linux/kobject.h> |
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#include <linux/export.h> #include <linux/kmod.h> |
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#include <linux/slab.h> |
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#include <linux/user_namespace.h> |
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#include <linux/socket.h> #include <linux/skbuff.h> #include <linux/netlink.h> |
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#include <net/sock.h> |
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#include <net/net_namespace.h> |
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u64 uevent_seqnum; |
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#ifdef CONFIG_UEVENT_HELPER |
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char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; |
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#endif |
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#ifdef CONFIG_NET struct uevent_sock { struct list_head list; struct sock *sk; }; static LIST_HEAD(uevent_sock_list); |
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#endif |
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/* This lock protects uevent_seqnum and uevent_sock_list */ static DEFINE_MUTEX(uevent_sock_mutex); |
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/* 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; |
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if (count && (buf[count-1] == ' ' || buf[count-1] == '\0')) |
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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; } |
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#ifdef CONFIG_NET |
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static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) { |
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struct kobject *kobj = data, *ksobj; |
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const struct kobj_ns_type_operations *ops; ops = kobj_ns_ops(kobj); |
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if (!ops && kobj->kset) { ksobj = &kobj->kset->kobj; if (ksobj->parent != NULL) ops = kobj_ns_ops(ksobj->parent); } if (ops && ops->netlink_ns && kobj->ktype->namespace) { |
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const void *sock_ns, *ns; ns = kobj->ktype->namespace(kobj); sock_ns = ops->netlink_ns(dsk); return sock_ns != ns; } return 0; } |
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#endif |
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#ifdef CONFIG_UEVENT_HELPER |
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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; } |
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static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) { int len; len = strlcpy(&env->buf[env->buflen], subsystem, sizeof(env->buf) - env->buflen); if (len >= (sizeof(env->buf) - env->buflen)) { WARN(1, KERN_ERR "init_uevent_argv: buffer size too small "); return -ENOMEM; } env->argv[0] = uevent_helper; env->argv[1] = &env->buf[env->buflen]; env->argv[2] = NULL; env->buflen += len + 1; return 0; } static void cleanup_uevent_env(struct subprocess_info *info) { kfree(info->data); } |
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#endif |
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/** |
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* kobject_uevent_env - send an uevent with environmental data |
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* |
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* @action: action that is happening |
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* @kobj: struct kobject that the action is happening to |
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* @envp_ext: pointer to environmental data |
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* |
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* Returns 0 if kobject_uevent_env() is completed with success or the |
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* corresponding error when it fails. |
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*/ |
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int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, |
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char *envp_ext[]) |
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{ |
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struct kobj_uevent_env *env; const char *action_string = kobject_actions[action]; |
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const char *devpath = NULL; const char *subsystem; struct kobject *top_kobj; struct kset *kset; |
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const struct kset_uevent_ops *uevent_ops; |
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int i = 0; |
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int retval = 0; |
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#ifdef CONFIG_NET struct uevent_sock *ue_sk; #endif |
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pr_debug("kobject: '%s' (%p): %s ", |
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kobject_name(kobj), kobj, __func__); |
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/* search the kset we belong to */ top_kobj = kobj; |
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while (!top_kobj->kset && top_kobj->parent) |
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top_kobj = top_kobj->parent; |
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if (!top_kobj->kset) { |
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pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " "without kset! ", kobject_name(kobj), kobj, |
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__func__); |
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return -EINVAL; } |
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kset = top_kobj->kset; |
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uevent_ops = kset->uevent_ops; |
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/* 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! ", kobject_name(kobj), kobj, __func__); return 0; } |
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/* skip the event, if the filter returns zero. */ |
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if (uevent_ops && uevent_ops->filter) |
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if (!uevent_ops->filter(kset, kobj)) { |
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pr_debug("kobject: '%s' (%p): %s: filter function " "caused the event to drop! ", |
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kobject_name(kobj), kobj, __func__); |
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return 0; } |
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/* originating subsystem */ if (uevent_ops && uevent_ops->name) subsystem = uevent_ops->name(kset, kobj); else subsystem = kobject_name(&kset->kobj); if (!subsystem) { |
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pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " "event to drop! ", kobject_name(kobj), kobj, |
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__func__); |
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return 0; } |
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/* environment buffer */ env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); if (!env) |
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return -ENOMEM; |
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/* complete object path */ devpath = kobject_get_path(kobj, GFP_KERNEL); |
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if (!devpath) { retval = -ENOENT; |
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goto exit; |
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} |
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/* default keys */ |
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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++) { |
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retval = add_uevent_var(env, "%s", envp_ext[i]); |
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if (retval) goto exit; } } |
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/* let the kset specific function add its stuff */ |
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if (uevent_ops && uevent_ops->uevent) { |
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retval = uevent_ops->uevent(kset, kobj, env); |
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if (retval) { |
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pr_debug("kobject: '%s' (%p): %s: uevent() returned " "%d ", kobject_name(kobj), kobj, |
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__func__, retval); |
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goto exit; } } |
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/* * 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; |
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mutex_lock(&uevent_sock_mutex); |
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/* we will send an event, so request a new sequence number */ |
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retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum); if (retval) { mutex_unlock(&uevent_sock_mutex); |
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goto exit; |
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} |
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#if defined(CONFIG_NET) |
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/* send netlink message */ |
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list_for_each_entry(ue_sk, &uevent_sock_list, list) { struct sock *uevent_sock = ue_sk->sk; |
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struct sk_buff *skb; size_t len; |
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if (!netlink_has_listeners(uevent_sock, 1)) continue; |
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/* allocate message with the maximum possible size */ len = strlen(action_string) + strlen(devpath) + 2; |
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skb = alloc_skb(len + env->buflen, GFP_KERNEL); |
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if (skb) { |
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char *scratch; |
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/* add header */ scratch = skb_put(skb, len); sprintf(scratch, "%s@%s", action_string, devpath); /* copy keys to our continuous event payload buffer */ |
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for (i = 0; i < env->envp_idx; i++) { len = strlen(env->envp[i]) + 1; |
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scratch = skb_put(skb, len); |
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strcpy(scratch, env->envp[i]); |
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} NETLINK_CB(skb).dst_group = 1; |
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retval = netlink_broadcast_filtered(uevent_sock, skb, 0, 1, GFP_KERNEL, kobj_bcast_filter, kobj); |
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/* ENOBUFS should be handled in userspace */ |
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if (retval == -ENOBUFS || retval == -ESRCH) |
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retval = 0; |
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} else retval = -ENOMEM; |
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} |
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#endif |
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mutex_unlock(&uevent_sock_mutex); |
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#ifdef CONFIG_UEVENT_HELPER |
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/* call uevent_helper, usually only enabled during early boot */ |
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if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { |
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struct subprocess_info *info; |
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retval = add_uevent_var(env, "HOME=/"); if (retval) goto exit; |
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retval = add_uevent_var(env, "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); |
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if (retval) goto exit; |
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retval = init_uevent_argv(env, subsystem); if (retval) goto exit; |
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retval = -ENOMEM; info = call_usermodehelper_setup(env->argv[0], env->argv, env->envp, GFP_KERNEL, NULL, cleanup_uevent_env, env); if (info) { retval = call_usermodehelper_exec(info, UMH_NO_WAIT); env = NULL; /* freed by cleanup_uevent_env */ } |
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} |
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#endif |
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exit: |
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kfree(devpath); |
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kfree(env); |
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return retval; |
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} |
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EXPORT_SYMBOL_GPL(kobject_uevent_env); /** |
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* kobject_uevent - notify userspace by sending an uevent |
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* |
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* @action: action that is happening |
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* @kobj: struct kobject that the action is happening to |
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* * Returns 0 if kobject_uevent() is completed with success or the * corresponding error when it fails. |
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*/ |
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int kobject_uevent(struct kobject *kobj, enum kobject_action action) |
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{ |
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return kobject_uevent_env(kobj, action, NULL); |
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} |
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EXPORT_SYMBOL_GPL(kobject_uevent); |
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/** |
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* add_uevent_var - add key value string to the environment buffer * @env: environment buffer structure * @format: printf format for the key=value pair |
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* * Returns 0 if environment variable was added successfully or -ENOMEM * if no space was available. */ |
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int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) |
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{ va_list args; |
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int len; |
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if (env->envp_idx >= ARRAY_SIZE(env->envp)) { |
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WARN(1, KERN_ERR "add_uevent_var: too many keys "); |
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return -ENOMEM; |
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} |
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va_start(args, format); |
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len = vsnprintf(&env->buf[env->buflen], sizeof(env->buf) - env->buflen, format, args); |
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va_end(args); |
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if (len >= (sizeof(env->buf) - env->buflen)) { |
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WARN(1, KERN_ERR "add_uevent_var: buffer size too small "); |
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return -ENOMEM; |
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} |
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env->envp[env->envp_idx++] = &env->buf[env->buflen]; env->buflen += len + 1; |
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return 0; } |
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EXPORT_SYMBOL_GPL(add_uevent_var); |
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#if defined(CONFIG_NET) |
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static int uevent_net_init(struct net *net) |
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{ |
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struct uevent_sock *ue_sk; |
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struct netlink_kernel_cfg cfg = { .groups = 1, |
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.flags = NL_CFG_F_NONROOT_RECV, |
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}; |
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ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); if (!ue_sk) return -ENOMEM; |
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ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg); |
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if (!ue_sk->sk) { |
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printk(KERN_ERR "kobject_uevent: unable to create netlink socket! "); |
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kfree(ue_sk); |
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return -ENODEV; } |
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mutex_lock(&uevent_sock_mutex); list_add_tail(&ue_sk->list, &uevent_sock_list); mutex_unlock(&uevent_sock_mutex); |
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return 0; } |
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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) { |
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return register_pernet_subsys(&uevent_net_ops); } |
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postcore_initcall(kobject_uevent_init); |
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#endif |