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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /lib/kobject_uevent.c
Initial import
Diffstat (limited to 'lib/kobject_uevent.c')
-rw-r--r--lib/kobject_uevent.c471
1 files changed, 471 insertions, 0 deletions
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
new file mode 100644
index 000000000..f6c2c1e77
--- /dev/null
+++ b/lib/kobject_uevent.c
@@ -0,0 +1,471 @@
+/*
+ * 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/export.h>
+#include <linux/kmod.h>
+#include <linux/slab.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;
+#ifdef CONFIG_UEVENT_HELPER
+char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
+#endif
+#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, *ksobj;
+ const struct kobj_ns_type_operations *ops;
+
+ ops = kobj_ns_ops(kobj);
+ 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) {
+ const void *sock_ns, *ns;
+ ns = kobj->ktype->namespace(kobj);
+ sock_ns = ops->netlink_ns(dsk);
+ return sock_ns != ns;
+ }
+
+ return 0;
+}
+#endif
+
+#ifdef CONFIG_UEVENT_HELPER
+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;
+}
+
+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\n");
+ 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);
+}
+#endif
+
+/**
+ * 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;
+
+ if (!netlink_has_listeners(uevent_sock, 1))
+ continue;
+
+ /* 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);
+
+#ifdef CONFIG_UEVENT_HELPER
+ /* call uevent_helper, usually only enabled during early boot */
+ if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
+ struct subprocess_info *info;
+
+ 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 = init_uevent_argv(env, subsystem);
+ if (retval)
+ goto exit;
+
+ 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 */
+ }
+ }
+#endif
+
+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;
+ struct netlink_kernel_cfg cfg = {
+ .groups = 1,
+ .flags = NL_CFG_F_NONROOT_RECV,
+ };
+
+ ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
+ if (!ue_sk)
+ return -ENOMEM;
+
+ ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg);
+ 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)
+{
+ return register_pernet_subsys(&uevent_net_ops);
+}
+
+
+postcore_initcall(kobject_uevent_init);
+#endif