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Subjectkdbus: add code for notifications and matches
Date
From: Daniel Mack <daniel@zonque.org>

This patch adds code for matches and notifications.

Notifications are broadcast messages generated by the kernel, which
notify subscribes when connections are created or destroyed, when
well-known-names have been claimed, released or changed ownership,
or when reply messages have timed out.

Matches are used to tell the kernel driver which broadcast messages
a connection is interested in. Matches can either be specific on one
of the kernel-generated notification types, or carry a bloom filter
mask to match against a message from userspace. The latter is a way
to pre-filter messages from other connections in order to mitigate
unnecessary wakeups.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
ipc/kdbus/match.c | 524 +++++++++++++++++++++++++++++++++++++++++++++++++++++
ipc/kdbus/match.h | 31 ++++
ipc/kdbus/notify.c | 235 ++++++++++++++++++++++++
ipc/kdbus/notify.h | 29 +++
4 files changed, 819 insertions(+)
create mode 100644 ipc/kdbus/match.c
create mode 100644 ipc/kdbus/match.h
create mode 100644 ipc/kdbus/notify.c
create mode 100644 ipc/kdbus/notify.h

diff --git a/ipc/kdbus/match.c b/ipc/kdbus/match.c
new file mode 100644
index 000000000000..e70ed28eff3f
--- /dev/null
+++ b/ipc/kdbus/match.c
@@ -0,0 +1,524 @@
+/*
+ * Copyright (C) 2013-2014 Kay Sievers
+ * Copyright (C) 2013-2014 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (C) 2013-2014 Daniel Mack <daniel@zonque.org>
+ * Copyright (C) 2013-2014 David Herrmann <dh.herrmann@gmail.com>
+ * Copyright (C) 2013-2014 Linux Foundation
+ * Copyright (C) 2014 Djalal Harouni <tixxdz@opendz.org>
+ *
+ * kdbus is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/fs.h>
+#include <linux/hash.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include "bus.h"
+#include "connection.h"
+#include "endpoint.h"
+#include "item.h"
+#include "match.h"
+#include "message.h"
+
+/**
+ * struct kdbus_match_db - message filters
+ * @entries_list: List of matches
+ * @mdb_rwlock: Match data lock
+ * @entries_count: Number of entries in database
+ */
+struct kdbus_match_db {
+ struct list_head entries_list;
+ struct rw_semaphore mdb_rwlock;
+ unsigned int entries_count;
+};
+
+/**
+ * struct kdbus_match_entry - a match database entry
+ * @cookie: User-supplied cookie to lookup the entry
+ * @list_entry: The list entry element for the db list
+ * @rules_list: The list head for tracking rules of this entry
+ */
+struct kdbus_match_entry {
+ u64 cookie;
+ struct list_head list_entry;
+ struct list_head rules_list;
+};
+
+/**
+ * struct kdbus_bloom_mask - mask to match against filter
+ * @generations: Number of generations carried
+ * @data: Array of bloom bit fields
+ */
+struct kdbus_bloom_mask {
+ u64 generations;
+ u64 *data;
+};
+
+/**
+ * struct kdbus_match_rule - a rule appended to a match entry
+ * @type: An item type to match agains
+ * @bloom_mask: Bloom mask to match a message's filter against, used
+ * with KDBUS_ITEM_BLOOM_MASK
+ * @name: Name to match against, used with KDBUS_ITEM_NAME,
+ * KDBUS_ITEM_NAME_{ADD,REMOVE,CHANGE}
+ * @old_id: ID to match against, used with
+ * KDBUS_ITEM_NAME_{ADD,REMOVE,CHANGE},
+ * KDBUS_ITEM_ID_REMOVE
+ * @new_id: ID to match against, used with
+ * KDBUS_ITEM_NAME_{ADD,REMOVE,CHANGE},
+ * KDBUS_ITEM_ID_REMOVE
+ * @src_id: ID to match against, used with KDBUS_ITEM_ID
+ * @rules_entry: Entry in the entry's rules list
+ */
+struct kdbus_match_rule {
+ u64 type;
+ union {
+ struct kdbus_bloom_mask bloom_mask;
+ struct {
+ char *name;
+ u64 old_id;
+ u64 new_id;
+ };
+ u64 src_id;
+ };
+ struct list_head rules_entry;
+};
+
+static void kdbus_match_rule_free(struct kdbus_match_rule *rule)
+{
+ switch (rule->type) {
+ case KDBUS_ITEM_BLOOM_MASK:
+ kfree(rule->bloom_mask.data);
+ break;
+
+ case KDBUS_ITEM_NAME:
+ case KDBUS_ITEM_NAME_ADD:
+ case KDBUS_ITEM_NAME_REMOVE:
+ case KDBUS_ITEM_NAME_CHANGE:
+ kfree(rule->name);
+ break;
+
+ case KDBUS_ITEM_ID:
+ case KDBUS_ITEM_ID_ADD:
+ case KDBUS_ITEM_ID_REMOVE:
+ break;
+
+ default:
+ BUG();
+ }
+
+ list_del(&rule->rules_entry);
+ kfree(rule);
+}
+
+static void kdbus_match_entry_free(struct kdbus_match_entry *entry)
+{
+ struct kdbus_match_rule *r, *tmp;
+
+ list_for_each_entry_safe(r, tmp, &entry->rules_list, rules_entry)
+ kdbus_match_rule_free(r);
+
+ list_del(&entry->list_entry);
+ kfree(entry);
+}
+
+/**
+ * kdbus_match_db_free() - free match db resources
+ * @mdb: The match database
+ */
+void kdbus_match_db_free(struct kdbus_match_db *mdb)
+{
+ struct kdbus_match_entry *entry, *tmp;
+
+ down_write(&mdb->mdb_rwlock);
+ list_for_each_entry_safe(entry, tmp, &mdb->entries_list, list_entry)
+ kdbus_match_entry_free(entry);
+ up_write(&mdb->mdb_rwlock);
+
+ kfree(mdb);
+}
+
+/**
+ * kdbus_match_db_new() - create a new match database
+ *
+ * Return: a new kdbus_match_db on success, ERR_PTR on failure.
+ */
+struct kdbus_match_db *kdbus_match_db_new(void)
+{
+ struct kdbus_match_db *d;
+
+ d = kzalloc(sizeof(*d), GFP_KERNEL);
+ if (!d)
+ return ERR_PTR(-ENOMEM);
+
+ init_rwsem(&d->mdb_rwlock);
+ INIT_LIST_HEAD(&d->entries_list);
+
+ return d;
+}
+
+static bool kdbus_match_bloom(const struct kdbus_bloom_filter *filter,
+ const struct kdbus_bloom_mask *mask,
+ const struct kdbus_conn *conn)
+{
+ size_t n = conn->ep->bus->bloom.size / sizeof(u64);
+ const u64 *m;
+ size_t i;
+
+ /*
+ * The message's filter carries a generation identifier, the
+ * match's mask possibly carries an array of multiple generations
+ * of the mask. Select the mask with the closest match of the
+ * filter's generation.
+ */
+ m = mask->data + (min(filter->generation, mask->generations - 1) * n);
+
+ /*
+ * The message's filter contains the messages properties,
+ * the match's mask contains the properties to look for in the
+ * message. Check the mask bit field against the filter bit field,
+ * if the message possibly carries the properties the connection
+ * has subscribed to.
+ */
+ for (i = 0; i < n; i++)
+ if ((filter->data[i] & m[i]) != m[i])
+ return false;
+
+ return true;
+}
+
+static bool kdbus_match_rules(const struct kdbus_match_entry *entry,
+ struct kdbus_conn *conn_src,
+ struct kdbus_kmsg *kmsg)
+{
+ struct kdbus_match_rule *r;
+
+ /*
+ * Walk all the rules and bail out immediately
+ * if any of them is unsatisfied.
+ */
+
+ list_for_each_entry(r, &entry->rules_list, rules_entry) {
+ if (conn_src == NULL) {
+ /* kernel notifications */
+
+ if (kmsg->notify_type != r->type)
+ return false;
+
+ switch (r->type) {
+ case KDBUS_ITEM_ID_ADD:
+ if (r->new_id != KDBUS_MATCH_ID_ANY &&
+ r->new_id != kmsg->notify_new_id)
+ return false;
+
+ break;
+
+ case KDBUS_ITEM_ID_REMOVE:
+ if (r->old_id != KDBUS_MATCH_ID_ANY &&
+ r->old_id != kmsg->notify_old_id)
+ return false;
+
+ break;
+
+ case KDBUS_ITEM_NAME_ADD:
+ case KDBUS_ITEM_NAME_CHANGE:
+ case KDBUS_ITEM_NAME_REMOVE:
+ if ((r->old_id != KDBUS_MATCH_ID_ANY &&
+ r->old_id != kmsg->notify_old_id) ||
+ (r->new_id != KDBUS_MATCH_ID_ANY &&
+ r->new_id != kmsg->notify_new_id) ||
+ (r->name && kmsg->notify_name &&
+ strcmp(r->name, kmsg->notify_name) != 0))
+ return false;
+
+ break;
+
+ default:
+ return false;
+ }
+ } else {
+ /* messages from userspace */
+
+ switch (r->type) {
+ case KDBUS_ITEM_BLOOM_MASK:
+ if (!kdbus_match_bloom(kmsg->bloom_filter,
+ &r->bloom_mask,
+ conn_src))
+ return false;
+ break;
+
+ case KDBUS_ITEM_ID:
+ if (r->src_id != conn_src->id &&
+ r->src_id != KDBUS_MATCH_ID_ANY)
+ return false;
+
+ break;
+
+ case KDBUS_ITEM_NAME:
+ if (!kdbus_conn_has_name(conn_src, r->name))
+ return false;
+
+ break;
+
+ default:
+ return false;
+ }
+ }
+ }
+
+ return true;
+}
+
+/**
+ * kdbus_match_db_match_kmsg() - match a kmsg object agains the database entries
+ * @mdb: The match database
+ * @conn_src: The connection object originating the message
+ * @kmsg: The kmsg to perform the match on
+ *
+ * This function will walk through all the database entries previously uploaded
+ * with kdbus_match_db_add(). As soon as any of them has an all-satisfied rule
+ * set, this function will return true.
+ *
+ * Return: true if there was a matching database entry, false otherwise.
+ */
+bool kdbus_match_db_match_kmsg(struct kdbus_match_db *mdb,
+ struct kdbus_conn *conn_src,
+ struct kdbus_kmsg *kmsg)
+{
+ struct kdbus_match_entry *entry;
+ bool matched = false;
+
+ down_read(&mdb->mdb_rwlock);
+ list_for_each_entry(entry, &mdb->entries_list, list_entry) {
+ matched = kdbus_match_rules(entry, conn_src, kmsg);
+ if (matched)
+ break;
+ }
+ up_read(&mdb->mdb_rwlock);
+
+ return matched;
+}
+
+static int kdbus_match_db_remove_unlocked(struct kdbus_match_db *mdb,
+ uint64_t cookie)
+{
+ struct kdbus_match_entry *entry, *tmp;
+ bool found = false;
+
+ list_for_each_entry_safe(entry, tmp, &mdb->entries_list, list_entry)
+ if (entry->cookie == cookie) {
+ kdbus_match_entry_free(entry);
+ --mdb->entries_count;
+ found = true;
+ }
+
+ return found ? 0 : -ENOENT;
+}
+
+/**
+ * kdbus_match_db_add() - add an entry to the match database
+ * @conn: The connection that was used in the ioctl call
+ * @cmd: The command as provided by the ioctl call
+ *
+ * This function is used in the context of the KDBUS_CMD_MATCH_ADD ioctl
+ * interface.
+ *
+ * One call to this function (or one ioctl(KDBUS_CMD_MATCH_ADD), respectively,
+ * adds one new database entry with n rules attached to it. Each rule is
+ * described with an kdbus_item, and an entry is considered matching if all
+ * its rules are satisfied.
+ *
+ * The items attached to a kdbus_cmd_match struct have the following mapping:
+ *
+ * KDBUS_ITEM_BLOOM_MASK: A bloom mask
+ * KDBUS_ITEM_NAME: A connection's source name
+ * KDBUS_ITEM_ID: A connection ID
+ * KDBUS_ITEM_NAME_ADD:
+ * KDBUS_ITEM_NAME_REMOVE:
+ * KDBUS_ITEM_NAME_CHANGE: Well-known name changes, carry
+ * kdbus_notify_name_change
+ * KDBUS_ITEM_ID_ADD:
+ * KDBUS_ITEM_ID_REMOVE: Connection ID changes, carry
+ * kdbus_notify_id_change
+ *
+ * For kdbus_notify_{id,name}_change structs, only the ID and name fields
+ * are looked at at when adding an entry. The flags are unused.
+ *
+ * Also note that KDBUS_ITEM_BLOOM_MASK, KDBUS_ITEM_NAME and KDBUS_ITEM_ID
+ * are used to match messages from userspace, while the others apply to
+ * kernel-generated notifications.
+ *
+ * Return: 0 on success, negative errno on failure
+ */
+int kdbus_match_db_add(struct kdbus_conn *conn,
+ struct kdbus_cmd_match *cmd)
+{
+ struct kdbus_match_entry *entry = NULL;
+ struct kdbus_match_db *mdb = conn->match_db;
+ struct kdbus_item *item;
+ int ret = 0;
+
+ lockdep_assert_held(conn);
+
+ entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry)
+ return -ENOMEM;
+
+ entry->cookie = cmd->cookie;
+ INIT_LIST_HEAD(&entry->list_entry);
+ INIT_LIST_HEAD(&entry->rules_list);
+
+ KDBUS_ITEMS_FOREACH(item, cmd->items, KDBUS_ITEMS_SIZE(cmd, items)) {
+ struct kdbus_match_rule *rule;
+ size_t size = item->size - offsetof(struct kdbus_item, data);
+
+ rule = kzalloc(sizeof(*rule), GFP_KERNEL);
+ if (!rule) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ switch (item->type) {
+ /* First matches for userspace messages */
+ case KDBUS_ITEM_BLOOM_MASK: {
+ u64 bsize = conn->ep->bus->bloom.size;
+ u64 generations;
+ u64 remainder;
+
+ generations = div64_u64_rem(size, bsize, &remainder);
+ if (size < bsize || remainder > 0) {
+ ret = -EDOM;
+ break;
+ }
+
+ rule->bloom_mask.data = kmemdup(item->data,
+ size, GFP_KERNEL);
+ if (!rule->bloom_mask.data) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ /* we get an array of n generations of bloom masks */
+ rule->bloom_mask.generations = generations;
+
+ break;
+ }
+
+ case KDBUS_ITEM_NAME:
+ /*
+ * Do not allow wildcard for now, since we
+ * must validate the wildcard first
+ */
+ if (!kdbus_name_is_valid(item->str, false)) {
+ ret = -EINVAL;
+ break;
+ }
+
+ rule->name = kstrdup(item->str, GFP_KERNEL);
+ if (!rule->name)
+ ret = -ENOMEM;
+
+ break;
+
+ case KDBUS_ITEM_ID:
+ rule->src_id = item->id;
+ break;
+
+ /* Now matches for kernel messages */
+ case KDBUS_ITEM_NAME_ADD:
+ case KDBUS_ITEM_NAME_REMOVE:
+ case KDBUS_ITEM_NAME_CHANGE: {
+ rule->old_id = item->name_change.old_id.id;
+ rule->new_id = item->name_change.new_id.id;
+
+ if (size > sizeof(struct kdbus_notify_name_change)) {
+ rule->name = kstrdup(item->name_change.name,
+ GFP_KERNEL);
+ if (!rule->name)
+ ret = -ENOMEM;
+ }
+
+ break;
+ }
+
+ case KDBUS_ITEM_ID_ADD:
+ case KDBUS_ITEM_ID_REMOVE:
+ if (item->type == KDBUS_ITEM_ID_ADD)
+ rule->new_id = item->id_change.id;
+ else
+ rule->old_id = item->id_change.id;
+
+ break;
+
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ if (ret < 0) {
+ kfree(rule);
+ break;
+ }
+
+ rule->type = item->type;
+
+ list_add_tail(&rule->rules_entry, &entry->rules_list);
+ }
+
+ down_write(&mdb->mdb_rwlock);
+
+ /* Remove any entry that has the same cookie as the current one. */
+ if (cmd->flags & KDBUS_MATCH_REPLACE)
+ kdbus_match_db_remove_unlocked(mdb, entry->cookie);
+
+ /*
+ * If the above removal caught any entry, there will be room for the
+ * new one.
+ */
+ if (++mdb->entries_count > KDBUS_MATCH_MAX) {
+ --mdb->entries_count;
+ ret = -EMFILE;
+ }
+
+ if (ret == 0)
+ list_add_tail(&entry->list_entry, &mdb->entries_list);
+ else
+ kdbus_match_entry_free(entry);
+
+ up_write(&mdb->mdb_rwlock);
+
+ return ret;
+}
+
+/**
+ * kdbus_match_db_remove() - remove an entry from the match database
+ * @conn: The connection that was used in the ioctl call
+ * @cmd: Pointer to the match data structure
+ *
+ * This function is used in the context of the KDBUS_CMD_MATCH_REMOVE
+ * ioctl interface.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int kdbus_match_db_remove(struct kdbus_conn *conn,
+ struct kdbus_cmd_match *cmd)
+{
+ struct kdbus_match_db *mdb = conn->match_db;
+ int ret;
+
+ lockdep_assert_held(conn);
+
+ down_write(&mdb->mdb_rwlock);
+ ret = kdbus_match_db_remove_unlocked(mdb, cmd->cookie);
+ up_write(&mdb->mdb_rwlock);
+
+ return ret;
+}
diff --git a/ipc/kdbus/match.h b/ipc/kdbus/match.h
new file mode 100644
index 000000000000..16b982ce607d
--- /dev/null
+++ b/ipc/kdbus/match.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2013-2014 Kay Sievers
+ * Copyright (C) 2013-2014 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (C) 2013-2014 Daniel Mack <daniel@zonque.org>
+ * Copyright (C) 2013-2014 David Herrmann <dh.herrmann@gmail.com>
+ * Copyright (C) 2013-2014 Linux Foundation
+ *
+ * kdbus is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ */
+
+#ifndef __KDBUS_MATCH_H
+#define __KDBUS_MATCH_H
+
+struct kdbus_conn;
+struct kdbus_kmsg;
+struct kdbus_match_db;
+
+struct kdbus_match_db *kdbus_match_db_new(void);
+void kdbus_match_db_free(struct kdbus_match_db *db);
+int kdbus_match_db_add(struct kdbus_conn *conn,
+ struct kdbus_cmd_match *cmd);
+int kdbus_match_db_remove(struct kdbus_conn *conn,
+ struct kdbus_cmd_match *cmd);
+bool kdbus_match_db_match_kmsg(struct kdbus_match_db *db,
+ struct kdbus_conn *conn_src,
+ struct kdbus_kmsg *kmsg);
+
+#endif
diff --git a/ipc/kdbus/notify.c b/ipc/kdbus/notify.c
new file mode 100644
index 000000000000..e212ec11927c
--- /dev/null
+++ b/ipc/kdbus/notify.c
@@ -0,0 +1,235 @@
+/*
+ * Copyright (C) 2013-2014 Kay Sievers
+ * Copyright (C) 2013-2014 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (C) 2013-2014 Daniel Mack <daniel@zonque.org>
+ * Copyright (C) 2013-2014 David Herrmann <dh.herrmann@gmail.com>
+ * Copyright (C) 2013-2014 Linux Foundation
+ *
+ * kdbus is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include "bus.h"
+#include "connection.h"
+#include "domain.h"
+#include "endpoint.h"
+#include "item.h"
+#include "message.h"
+#include "notify.h"
+
+static int kdbus_notify_reply(struct kdbus_bus *bus, u64 id,
+ u64 cookie, u64 msg_type)
+{
+ struct kdbus_kmsg *kmsg = NULL;
+
+ BUG_ON(id == 0);
+
+ kmsg = kdbus_kmsg_new(0);
+ if (IS_ERR(kmsg))
+ return PTR_ERR(kmsg);
+
+ /*
+ * a kernel-generated notification can only contain one
+ * struct kdbus_item, so make a shortcut here for
+ * faster lookup in the match db.
+ */
+ kmsg->notify_type = msg_type;
+ kmsg->msg.dst_id = id;
+ kmsg->msg.src_id = KDBUS_SRC_ID_KERNEL;
+ kmsg->msg.payload_type = KDBUS_PAYLOAD_KERNEL;
+ kmsg->msg.cookie_reply = cookie;
+ kmsg->msg.items[0].type = msg_type;
+
+ spin_lock(&bus->notify_lock);
+ list_add_tail(&kmsg->notify_entry, &bus->notify_list);
+ spin_unlock(&bus->notify_lock);
+ return 0;
+}
+
+/**
+ * kdbus_notify_reply_timeout() - queue a timeout reply
+ * @bus: Bus which queues the messages
+ * @id: The destination's connection ID
+ * @cookie: The cookie to set in the reply.
+ *
+ * Queues a message that has a KDBUS_ITEM_REPLY_TIMEOUT item attached.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int kdbus_notify_reply_timeout(struct kdbus_bus *bus, u64 id, u64 cookie)
+{
+ return kdbus_notify_reply(bus, id, cookie, KDBUS_ITEM_REPLY_TIMEOUT);
+}
+
+/**
+ * kdbus_notify_reply_dead() - queue a 'dead' reply
+ * @bus: Bus which queues the messages
+ * @id: The destination's connection ID
+ * @cookie: The cookie to set in the reply.
+ *
+ * Queues a message that has a KDBUS_ITEM_REPLY_DEAD item attached.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int kdbus_notify_reply_dead(struct kdbus_bus *bus, u64 id, u64 cookie)
+{
+ return kdbus_notify_reply(bus, id, cookie, KDBUS_ITEM_REPLY_DEAD);
+}
+
+/**
+ * kdbus_notify_name_change() - queue a notification about a name owner change
+ * @bus: Bus which queues the messages
+ * @type: The type if the notification; KDBUS_ITEM_NAME_ADD,
+ * KDBUS_ITEM_NAME_CHANGE or KDBUS_ITEM_NAME_REMOVE
+ * @old_id: The id of the connection that used to own the name
+ * @new_id: The id of the new owner connection
+ * @old_flags: The flags to pass in the KDBUS_ITEM flags field for
+ * the old owner
+ * @new_flags: The flags to pass in the KDBUS_ITEM flags field for
+ * the new owner
+ * @name: The name that was removed or assigned to a new owner
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int kdbus_notify_name_change(struct kdbus_bus *bus, u64 type,
+ u64 old_id, u64 new_id,
+ u64 old_flags, u64 new_flags,
+ const char *name)
+{
+ struct kdbus_kmsg *kmsg = NULL;
+ size_t name_len, extra_size;
+
+ name_len = strlen(name) + 1;
+ extra_size = sizeof(struct kdbus_notify_name_change) + name_len;
+ kmsg = kdbus_kmsg_new(extra_size);
+ if (IS_ERR(kmsg))
+ return PTR_ERR(kmsg);
+
+ kmsg->msg.dst_id = KDBUS_DST_ID_BROADCAST;
+ kmsg->msg.src_id = KDBUS_SRC_ID_KERNEL;
+ kmsg->msg.payload_type = KDBUS_PAYLOAD_KERNEL;
+ kmsg->notify_type = type;
+ kmsg->notify_old_id = old_id;
+ kmsg->notify_new_id = new_id;
+ kmsg->msg.items[0].type = type;
+ kmsg->msg.items[0].name_change.old_id.id = old_id;
+ kmsg->msg.items[0].name_change.old_id.flags = old_flags;
+ kmsg->msg.items[0].name_change.new_id.id = new_id;
+ kmsg->msg.items[0].name_change.new_id.flags = new_flags;
+ memcpy(kmsg->msg.items[0].name_change.name, name, name_len);
+ kmsg->notify_name = kmsg->msg.items[0].name_change.name;
+
+ spin_lock(&bus->notify_lock);
+ list_add_tail(&kmsg->notify_entry, &bus->notify_list);
+ spin_unlock(&bus->notify_lock);
+ return 0;
+}
+
+/**
+ * kdbus_notify_id_change() - queue a notification about a unique ID change
+ * @bus: Bus which queues the messages
+ * @type: The type if the notification; KDBUS_ITEM_ID_ADD or
+ * KDBUS_ITEM_ID_REMOVE
+ * @id: The id of the connection that was added or removed
+ * @flags: The flags to pass in the KDBUS_ITEM flags field
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int kdbus_notify_id_change(struct kdbus_bus *bus, u64 type, u64 id, u64 flags)
+{
+ struct kdbus_kmsg *kmsg = NULL;
+
+ kmsg = kdbus_kmsg_new(sizeof(struct kdbus_notify_id_change));
+ if (IS_ERR(kmsg))
+ return PTR_ERR(kmsg);
+
+ kmsg->msg.dst_id = KDBUS_DST_ID_BROADCAST;
+ kmsg->msg.src_id = KDBUS_SRC_ID_KERNEL;
+ kmsg->msg.payload_type = KDBUS_PAYLOAD_KERNEL;
+ kmsg->notify_type = type;
+
+ switch (type) {
+ case KDBUS_ITEM_ID_ADD:
+ kmsg->notify_new_id = id;
+ break;
+
+ case KDBUS_ITEM_ID_REMOVE:
+ kmsg->notify_old_id = id;
+ break;
+
+ default:
+ BUG();
+ }
+
+ kmsg->msg.items[0].type = type;
+ kmsg->msg.items[0].id_change.id = id;
+ kmsg->msg.items[0].id_change.flags = flags;
+
+ spin_lock(&bus->notify_lock);
+ list_add_tail(&kmsg->notify_entry, &bus->notify_list);
+ spin_unlock(&bus->notify_lock);
+ return 0;
+}
+
+/**
+ * kdbus_notify_flush() - send a list of collected messages
+ * @bus: Bus which queues the messages
+ *
+ * The list is empty after sending the messages.
+ */
+void kdbus_notify_flush(struct kdbus_bus *bus)
+{
+ LIST_HEAD(notify_list);
+ struct kdbus_kmsg *kmsg, *tmp;
+
+ mutex_lock(&bus->notify_flush_lock);
+
+ spin_lock(&bus->notify_lock);
+ list_splice_init(&bus->notify_list, &notify_list);
+ spin_unlock(&bus->notify_lock);
+
+ list_for_each_entry_safe(kmsg, tmp, &notify_list, notify_entry) {
+ kmsg->seq = atomic64_inc_return(&bus->domain->msg_seq_last);
+
+ if (kmsg->msg.dst_id != KDBUS_DST_ID_BROADCAST) {
+ struct kdbus_conn *conn;
+
+ conn = kdbus_bus_find_conn_by_id(bus, kmsg->msg.dst_id);
+ if (conn) {
+ kdbus_conn_entry_insert(NULL, conn, kmsg, NULL);
+ kdbus_conn_unref(conn);
+ }
+ } else {
+ kdbus_bus_broadcast(bus, NULL, kmsg);
+ }
+
+ list_del(&kmsg->notify_entry);
+ kdbus_kmsg_free(kmsg);
+ }
+
+ mutex_unlock(&bus->notify_flush_lock);
+}
+
+/**
+ * kdbus_notify_free() - free a list of collected messages
+ * @bus: Bus which queues the messages
+ */
+void kdbus_notify_free(struct kdbus_bus *bus)
+{
+ struct kdbus_kmsg *kmsg, *tmp;
+
+ list_for_each_entry_safe(kmsg, tmp, &bus->notify_list, notify_entry) {
+ list_del(&kmsg->notify_entry);
+ kdbus_kmsg_free(kmsg);
+ }
+}
diff --git a/ipc/kdbus/notify.h b/ipc/kdbus/notify.h
new file mode 100644
index 000000000000..95d3711e49f3
--- /dev/null
+++ b/ipc/kdbus/notify.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2013-2014 Kay Sievers
+ * Copyright (C) 2013-2014 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (C) 2013-2014 Daniel Mack <daniel@zonque.org>
+ * Copyright (C) 2013-2014 David Herrmann <dh.herrmann@gmail.com>
+ * Copyright (C) 2013-2014 Linux Foundation
+ *
+ * kdbus is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ */
+
+#ifndef __KDBUS_NOTIFY_H
+#define __KDBUS_NOTIFY_H
+
+struct kdbus_bus;
+
+int kdbus_notify_id_change(struct kdbus_bus *bus, u64 type, u64 id, u64 flags);
+int kdbus_notify_reply_timeout(struct kdbus_bus *bus, u64 id, u64 cookie);
+int kdbus_notify_reply_dead(struct kdbus_bus *bus, u64 id, u64 cookie);
+int kdbus_notify_name_change(struct kdbus_bus *bus, u64 type,
+ u64 old_id, u64 new_id,
+ u64 old_flags, u64 new_flags,
+ const char *name);
+void kdbus_notify_flush(struct kdbus_bus *bus);
+void kdbus_notify_free(struct kdbus_bus *bus);
+
+#endif
--
2.1.3


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