Fixed MTP to work with TWRP

lib/kobject_uevent.c

@@ -0,0 +1,472 @@
+/*
+ * 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/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;
+#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