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Subjectkdbus: add name registry implementation
Date
From: Daniel Mack <daniel@zonque.org>

This patch adds the name registry implementation.

Each bus instantiates a name registry to resolve well-known names
into unique connection IDs for message delivery. The registry will
be queried when a message is sent with kdbus_msg.dst_id set to
KDBUS_DST_ID_NAME, or when a registry dump is requested.

It's important to have this registry implemented in the kernel to
implement lookups and take-overs in a race-free way.

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/names.c | 921 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
ipc/kdbus/names.h | 81 +++++
2 files changed, 1002 insertions(+)
create mode 100644 ipc/kdbus/names.c
create mode 100644 ipc/kdbus/names.h

diff --git a/ipc/kdbus/names.c b/ipc/kdbus/names.c
new file mode 100644
index 000000000000..552309bd6716
--- /dev/null
+++ b/ipc/kdbus/names.c
@@ -0,0 +1,921 @@
+/*
+ * 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
+ *
+ * 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/ctype.h>
+#include <linux/fs.h>
+#include <linux/hash.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include "bus.h"
+#include "connection.h"
+#include "endpoint.h"
+#include "item.h"
+#include "names.h"
+#include "notify.h"
+#include "policy.h"
+
+/**
+ * struct kdbus_name_queue_item - a queue item for a name
+ * @conn: The associated connection
+ * @entry: Name entry queuing up for
+ * @entry_entry: List element for the list in @entry
+ * @conn_entry: List element for the list in @conn
+ * @flags: The queuing flags
+ */
+struct kdbus_name_queue_item {
+ struct kdbus_conn *conn;
+ struct kdbus_name_entry *entry;
+ struct list_head entry_entry;
+ struct list_head conn_entry;
+ u64 flags;
+};
+
+static void kdbus_name_entry_free(struct kdbus_name_entry *e)
+{
+ hash_del(&e->hentry);
+ kfree(e->name);
+ kfree(e);
+}
+
+/**
+ * kdbus_name_registry_free() - drop a name reg's reference
+ * @reg: The name registry, may be %NULL
+ *
+ * Cleanup the name registry's internal structures.
+ */
+void kdbus_name_registry_free(struct kdbus_name_registry *reg)
+{
+ struct kdbus_name_entry *e;
+ struct hlist_node *tmp;
+ unsigned int i;
+
+ if (!reg)
+ return;
+
+ hash_for_each_safe(reg->entries_hash, i, tmp, e, hentry)
+ kdbus_name_entry_free(e);
+
+ kfree(reg);
+}
+
+/**
+ * kdbus_name_registry_new() - create a new name registry
+ *
+ * Return: a new kdbus_name_registry on success, ERR_PTR on failure.
+ */
+struct kdbus_name_registry *kdbus_name_registry_new(void)
+{
+ struct kdbus_name_registry *r;
+
+ r = kzalloc(sizeof(*r), GFP_KERNEL);
+ if (!r)
+ return ERR_PTR(-ENOMEM);
+
+ hash_init(r->entries_hash);
+ init_rwsem(&r->rwlock);
+
+ return r;
+}
+
+static struct kdbus_name_entry *
+kdbus_name_lookup(struct kdbus_name_registry *reg, u32 hash, const char *name)
+{
+ struct kdbus_name_entry *e;
+
+ hash_for_each_possible(reg->entries_hash, e, hentry, hash)
+ if (strcmp(e->name, name) == 0)
+ return e;
+
+ return NULL;
+}
+
+static void kdbus_name_queue_item_free(struct kdbus_name_queue_item *q)
+{
+ list_del(&q->entry_entry);
+ list_del(&q->conn_entry);
+ kfree(q);
+}
+
+/*
+ * The caller must hold the lock so we decrement the counter and
+ * delete the entry.
+ *
+ * The caller needs to hold its own reference, so the connection does not go
+ * away while the entry's reference is dropped under lock.
+ */
+static void kdbus_name_entry_remove_owner(struct kdbus_name_entry *e)
+{
+ BUG_ON(!e->conn);
+ BUG_ON(!mutex_is_locked(&e->conn->lock));
+
+ atomic_dec(&e->conn->name_count);
+ list_del(&e->conn_entry);
+ e->conn = kdbus_conn_unref(e->conn);
+}
+
+static void kdbus_name_entry_set_owner(struct kdbus_name_entry *e,
+ struct kdbus_conn *conn)
+{
+ BUG_ON(e->conn);
+ BUG_ON(!mutex_is_locked(&conn->lock));
+
+ e->conn = kdbus_conn_ref(conn);
+ atomic_inc(&conn->name_count);
+ list_add_tail(&e->conn_entry, &e->conn->names_list);
+}
+
+static int kdbus_name_replace_owner(struct kdbus_name_entry *e,
+ struct kdbus_conn *conn, u64 flags)
+{
+ struct kdbus_conn *conn_old = kdbus_conn_ref(e->conn);
+ int ret;
+
+ BUG_ON(conn == conn_old);
+ BUG_ON(!conn_old);
+
+ /* take lock of both connections in a defined order */
+ if (conn < conn_old) {
+ mutex_lock(&conn->lock);
+ mutex_lock_nested(&conn_old->lock, 1);
+ } else {
+ mutex_lock(&conn_old->lock);
+ mutex_lock_nested(&conn->lock, 1);
+ }
+
+ if (!kdbus_conn_active(conn)) {
+ ret = -ECONNRESET;
+ goto exit_unlock;
+ }
+
+ ret = kdbus_notify_name_change(conn->ep->bus, KDBUS_ITEM_NAME_CHANGE,
+ e->conn->id, conn->id,
+ e->flags, flags, e->name);
+ if (ret < 0)
+ goto exit_unlock;
+
+ /* hand over name ownership */
+ kdbus_name_entry_remove_owner(e);
+ kdbus_name_entry_set_owner(e, conn);
+ e->flags = flags;
+
+exit_unlock:
+ mutex_unlock(&conn_old->lock);
+ mutex_unlock(&conn->lock);
+
+ kdbus_conn_unref(conn_old);
+ return ret;
+}
+
+static int kdbus_name_entry_release(struct kdbus_name_entry *e,
+ struct kdbus_bus *bus)
+{
+ struct kdbus_conn *conn;
+
+ /* give it to first active waiter in the queue */
+ while (!list_empty(&e->queue_list)) {
+ struct kdbus_name_queue_item *q;
+ int ret;
+
+ q = list_first_entry(&e->queue_list,
+ struct kdbus_name_queue_item,
+ entry_entry);
+
+ ret = kdbus_name_replace_owner(e, q->conn, q->flags);
+ if (ret < 0)
+ continue;
+
+ kdbus_name_queue_item_free(q);
+ return 0;
+ }
+
+ /* hand it back to an active activator connection */
+ if (e->activator && e->activator != e->conn) {
+ u64 flags = KDBUS_NAME_ACTIVATOR;
+ int ret;
+
+ /*
+ * Move messages still queued in the old connection
+ * and addressed to that name to the new connection.
+ * This allows a race and loss-free name and message
+ * takeover and exit-on-idle services.
+ */
+ ret = kdbus_conn_move_messages(e->activator, e->conn,
+ e->name_id);
+ if (ret < 0)
+ goto exit_release;
+
+ return kdbus_name_replace_owner(e, e->activator, flags);
+ }
+
+exit_release:
+ /* release the name */
+ kdbus_notify_name_change(e->conn->ep->bus, KDBUS_ITEM_NAME_REMOVE,
+ e->conn->id, 0,
+ e->flags, 0, e->name);
+
+ conn = kdbus_conn_ref(e->conn);
+ mutex_lock(&conn->lock);
+ kdbus_name_entry_remove_owner(e);
+ mutex_unlock(&conn->lock);
+ kdbus_conn_unref(conn);
+
+ kdbus_conn_unref(e->activator);
+ kdbus_name_entry_free(e);
+
+ return 0;
+}
+
+static int kdbus_name_release(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn,
+ const char *name)
+{
+ struct kdbus_name_queue_item *q_tmp, *q;
+ struct kdbus_name_entry *e = NULL;
+ u32 hash;
+ int ret = 0;
+
+ hash = kdbus_str_hash(name);
+
+ /* lock order: domain -> bus -> ep -> names -> connection */
+ mutex_lock(&conn->ep->bus->lock);
+ down_write(&reg->rwlock);
+
+ e = kdbus_name_lookup(reg, hash, name);
+ if (!e) {
+ ret = -ESRCH;
+ goto exit_unlock;
+ }
+
+ /* Is the connection already the real owner of the name? */
+ if (e->conn == conn) {
+ ret = kdbus_name_entry_release(e, conn->ep->bus);
+ } else {
+ /*
+ * Otherwise, walk the list of queued entries and search
+ * for items for connection.
+ */
+
+ /* In case the name belongs to somebody else */
+ ret = -EADDRINUSE;
+
+ list_for_each_entry_safe(q, q_tmp,
+ &e->queue_list,
+ entry_entry) {
+ if (q->conn != conn)
+ continue;
+
+ kdbus_name_queue_item_free(q);
+ ret = 0;
+ break;
+ }
+ }
+
+ /*
+ * Now that the connection has lost a name, purge all cached policy
+ * entries, so upon the next message, TALK access will be checked
+ * against the names the connection actually owns.
+ */
+ if (ret == 0)
+ kdbus_conn_purge_policy_cache(conn);
+
+exit_unlock:
+ up_write(&reg->rwlock);
+ mutex_unlock(&conn->ep->bus->lock);
+
+ return ret;
+}
+
+/**
+ * kdbus_name_remove_by_conn() - remove all name entries of a given connection
+ * @reg: The name registry
+ * @conn: The connection which entries to remove
+ *
+ * This function removes all name entry held by a given connection.
+ */
+void kdbus_name_remove_by_conn(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn)
+{
+ struct kdbus_name_queue_item *q_tmp, *q;
+ struct kdbus_conn *activator = NULL;
+ struct kdbus_name_entry *e_tmp, *e;
+ LIST_HEAD(names_queue_list);
+ LIST_HEAD(names_list);
+
+ /* lock order: domain -> bus -> ep -> names -> conn */
+ mutex_lock(&conn->ep->bus->lock);
+ down_write(&reg->rwlock);
+
+ mutex_lock(&conn->lock);
+ list_splice_init(&conn->names_list, &names_list);
+ list_splice_init(&conn->names_queue_list, &names_queue_list);
+ mutex_unlock(&conn->lock);
+
+ if (kdbus_conn_is_activator(conn)) {
+ activator = conn->activator_of->activator;
+ conn->activator_of->activator = NULL;
+ }
+ list_for_each_entry_safe(q, q_tmp, &names_queue_list, conn_entry)
+ kdbus_name_queue_item_free(q);
+ list_for_each_entry_safe(e, e_tmp, &names_list, conn_entry)
+ kdbus_name_entry_release(e, conn->ep->bus);
+
+ up_write(&reg->rwlock);
+ mutex_unlock(&conn->ep->bus->lock);
+
+ kdbus_conn_unref(activator);
+ kdbus_notify_flush(conn->ep->bus);
+}
+
+/**
+ * kdbus_name_lock() - look up a name in a name registry and lock it
+ * @reg: The name registry
+ * @name: The name to look up
+ *
+ * Search for a name in a given name registry and return it with the
+ * registry-lock held. If the object is not found, the lock is not acquired and
+ * NULL is returned. The caller is responsible of unlocking the name via
+ * kdbus_name_unlock() again. Note that kdbus_name_unlock() can be safely called
+ * with NULL as name. In this case, it's a no-op as nothing was locked.
+ *
+ * The *_lock() + *_unlock() logic is only required for callers that need to
+ * protect their code against concurrent activator/implementor name changes.
+ * Multiple readers can lock names concurrently. However, you may not change
+ * name-ownership while holding a name-lock.
+ *
+ * Return: NULL if name is unknown, otherwise return a pointer to the name
+ * entry with the name-lock held (reader lock only).
+ */
+struct kdbus_name_entry *kdbus_name_lock(struct kdbus_name_registry *reg,
+ const char *name)
+{
+ struct kdbus_name_entry *e = NULL;
+ u32 hash = kdbus_str_hash(name);
+
+ down_read(&reg->rwlock);
+ e = kdbus_name_lookup(reg, hash, name);
+ if (e)
+ return e;
+ up_read(&reg->rwlock);
+
+ return NULL;
+}
+
+/**
+ * kdbus_name_unlock() - unlock one name in a name registry
+ * @reg: The name registry
+ * @entry: The locked name entry or NULL
+ *
+ * This is the unlock-counterpart of kdbus_name_lock(). It unlocks a name that
+ * was previously successfully locked. You can safely pass NULL as entry and
+ * this will become a no-op. Therefore, it's safe to always call this on the
+ * return-value of kdbus_name_lock().
+ *
+ * Return: This always returns NULL.
+ */
+struct kdbus_name_entry *kdbus_name_unlock(struct kdbus_name_registry *reg,
+ struct kdbus_name_entry *entry)
+{
+ if (entry) {
+ BUG_ON(!rwsem_is_locked(&reg->rwlock));
+ up_read(&reg->rwlock);
+ }
+
+ return NULL;
+}
+
+static int kdbus_name_queue_conn(struct kdbus_conn *conn, u64 flags,
+ struct kdbus_name_entry *e)
+{
+ struct kdbus_name_queue_item *q;
+
+ q = kzalloc(sizeof(*q), GFP_KERNEL);
+ if (!q)
+ return -ENOMEM;
+
+ q->conn = conn;
+ q->flags = flags;
+ q->entry = e;
+
+ list_add_tail(&q->entry_entry, &e->queue_list);
+ list_add_tail(&q->conn_entry, &conn->names_queue_list);
+
+ return 0;
+}
+
+/**
+ * kdbus_name_is_valid() - check if a name is valid
+ * @p: The name to check
+ * @allow_wildcard: Whether or not to allow a wildcard name
+ *
+ * A name is valid if all of the following criterias are met:
+ *
+ * - The name has two or more elements separated by a period ('.') character.
+ * - All elements must contain at least one character.
+ * - Each element must only contain the ASCII characters "[A-Z][a-z][0-9]_-"
+ * and must not begin with a digit.
+ * - The name must not exceed KDBUS_NAME_MAX_LEN.
+ * - If @allow_wildcard is true, the name may end on '.*'
+ */
+bool kdbus_name_is_valid(const char *p, bool allow_wildcard)
+{
+ bool dot, found_dot = false;
+ const char *q;
+
+ for (dot = true, q = p; *q; q++) {
+ if (*q == '.') {
+ if (dot)
+ return false;
+
+ found_dot = true;
+ dot = true;
+ } else {
+ bool good;
+
+ good = isalpha(*q) || (!dot && isdigit(*q)) ||
+ *q == '_' || *q == '-' ||
+ (allow_wildcard && dot &&
+ *q == '*' && *(q + 1) == '\0');
+
+ if (!good)
+ return false;
+
+ dot = false;
+ }
+ }
+
+ if (q - p > KDBUS_NAME_MAX_LEN)
+ return false;
+
+ if (dot)
+ return false;
+
+ if (!found_dot)
+ return false;
+
+ return true;
+}
+
+/**
+ * kdbus_name_acquire() - acquire a name
+ * @reg: The name registry
+ * @conn: The connection to pin this entry to
+ * @name: The name to acquire
+ * @flags: Acquisition flags (KDBUS_NAME_*)
+ *
+ * Callers must ensure that @conn is either a privileged bus user or has
+ * sufficient privileges in the policy-db to own the well-known name @name.
+ *
+ * Return: 0 success, negative error number on failure.
+ */
+int kdbus_name_acquire(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn,
+ const char *name, u64 *flags)
+{
+ struct kdbus_name_entry *e = NULL;
+ u32 hash;
+ int ret = 0;
+
+ /* lock order: domain -> bus -> ep -> names -> conn */
+ mutex_lock(&conn->ep->bus->lock);
+ down_write(&reg->rwlock);
+
+ hash = kdbus_str_hash(name);
+ e = kdbus_name_lookup(reg, hash, name);
+ if (e) {
+ /* connection already owns that name */
+ if (e->conn == conn) {
+ ret = -EALREADY;
+ goto exit_unlock;
+ }
+
+ if (kdbus_conn_is_activator(conn)) {
+ /* An activator can only own a single name */
+ if (conn->activator_of) {
+ if (conn->activator_of == e)
+ ret = -EALREADY;
+ else
+ ret = -EINVAL;
+ } else if (!e->activator && !conn->activator_of) {
+ /*
+ * Activator registers for name that is
+ * already owned
+ */
+ e->activator = kdbus_conn_ref(conn);
+ conn->activator_of = e;
+ }
+
+ goto exit_unlock;
+ }
+
+ /* take over the name of an activator connection */
+ if (e->flags & KDBUS_NAME_ACTIVATOR) {
+ /*
+ * Take over the messages queued in the activator
+ * connection, the activator itself never reads them.
+ */
+ ret = kdbus_conn_move_messages(conn, e->activator, 0);
+ if (ret < 0)
+ goto exit_unlock;
+
+ ret = kdbus_name_replace_owner(e, conn, *flags);
+ goto exit_unlock;
+ }
+
+ /* take over the name if both parties agree */
+ if ((*flags & KDBUS_NAME_REPLACE_EXISTING) &&
+ (e->flags & KDBUS_NAME_ALLOW_REPLACEMENT)) {
+ /*
+ * Move name back to the queue, in case we take it away
+ * from a connection which asked for queuing.
+ */
+ if (e->flags & KDBUS_NAME_QUEUE) {
+ ret = kdbus_name_queue_conn(e->conn,
+ e->flags, e);
+ if (ret < 0)
+ goto exit_unlock;
+ }
+
+ ret = kdbus_name_replace_owner(e, conn, *flags);
+ goto exit_unlock;
+ }
+
+ /* add it to the queue waiting for the name */
+ if (*flags & KDBUS_NAME_QUEUE) {
+ ret = kdbus_name_queue_conn(conn, *flags, e);
+
+ /* tell the caller that we queued it */
+ *flags |= KDBUS_NAME_IN_QUEUE;
+
+ goto exit_unlock;
+ }
+
+ /* the name is busy, return a failure */
+ ret = -EEXIST;
+ goto exit_unlock;
+ } else {
+ /* An activator can only own a single name */
+ if (kdbus_conn_is_activator(conn) &&
+ conn->activator_of) {
+ ret = -EINVAL;
+ goto exit_unlock;
+ }
+ }
+
+ /* new name entry */
+ e = kzalloc(sizeof(*e), GFP_KERNEL);
+ if (!e) {
+ ret = -ENOMEM;
+ goto exit_unlock;
+ }
+
+ e->name = kstrdup(name, GFP_KERNEL);
+ if (!e->name) {
+ kfree(e);
+ ret = -ENOMEM;
+ goto exit_unlock;
+ }
+
+ if (kdbus_conn_is_activator(conn)) {
+ e->activator = kdbus_conn_ref(conn);
+ conn->activator_of = e;
+ }
+
+ e->flags = *flags;
+ INIT_LIST_HEAD(&e->queue_list);
+ e->name_id = ++reg->name_seq_last;
+
+ mutex_lock(&conn->lock);
+ if (!kdbus_conn_active(conn)) {
+ mutex_unlock(&conn->lock);
+ kfree(e);
+ ret = -ECONNRESET;
+ goto exit_unlock;
+ }
+ hash_add(reg->entries_hash, &e->hentry, hash);
+ kdbus_name_entry_set_owner(e, conn);
+ mutex_unlock(&conn->lock);
+
+ kdbus_notify_name_change(e->conn->ep->bus, KDBUS_ITEM_NAME_ADD,
+ 0, e->conn->id,
+ 0, e->flags, e->name);
+
+exit_unlock:
+ up_write(&reg->rwlock);
+ mutex_unlock(&conn->ep->bus->lock);
+ kdbus_notify_flush(conn->ep->bus);
+ return ret;
+}
+
+/**
+ * kdbus_cmd_name_acquire() - acquire a name from a ioctl command buffer
+ * @reg: The name registry
+ * @conn: The connection to pin this entry to
+ * @cmd: The command as passed in by the ioctl
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int kdbus_cmd_name_acquire(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn,
+ struct kdbus_cmd_name *cmd)
+{
+ const char *name;
+ int ret;
+
+ name = kdbus_items_get_str(cmd->items, KDBUS_ITEMS_SIZE(cmd, items),
+ KDBUS_ITEM_NAME);
+ if (IS_ERR(name))
+ return -EINVAL;
+
+ if (!kdbus_name_is_valid(name, false))
+ return -EINVAL;
+
+ /*
+ * Do atomic_inc_return here to reserve our slot, then decrement
+ * it before returning.
+ */
+ if (atomic_inc_return(&conn->name_count) > KDBUS_CONN_MAX_NAMES) {
+ ret = -E2BIG;
+ goto out_dec;
+ }
+
+ ret = kdbus_ep_policy_check_own_access(conn->ep, conn, name);
+ if (ret < 0)
+ goto out_dec;
+
+ ret = kdbus_name_acquire(reg, conn, name, &cmd->flags);
+ kdbus_notify_flush(conn->ep->bus);
+
+out_dec:
+ /* Decrement the previous allocated slot */
+ atomic_dec(&conn->name_count);
+ return ret;
+}
+
+/**
+ * kdbus_cmd_name_release() - release a name entry from a ioctl command buffer
+ * @reg: The name registry
+ * @conn: The connection that holds the name
+ * @cmd: The command as passed in by the ioctl
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int kdbus_cmd_name_release(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn,
+ const struct kdbus_cmd_name *cmd)
+{
+ int ret;
+ const char *name;
+
+ name = kdbus_items_get_str(cmd->items, KDBUS_ITEMS_SIZE(cmd, items),
+ KDBUS_ITEM_NAME);
+ if (IS_ERR(name))
+ return -EINVAL;
+
+ if (!kdbus_name_is_valid(name, false))
+ return -EINVAL;
+
+ ret = kdbus_ep_policy_check_see_access(conn->ep, conn, name);
+ if (ret < 0)
+ return ret;
+
+ ret = kdbus_name_release(reg, conn, name);
+
+ kdbus_notify_flush(conn->ep->bus);
+ return ret;
+}
+
+static int kdbus_name_list_write(struct kdbus_conn *conn,
+ struct kdbus_conn *c,
+ struct kdbus_pool_slice *slice,
+ size_t *pos,
+ struct kdbus_name_entry *e,
+ bool write)
+{
+ const size_t len = sizeof(struct kdbus_name_info);
+ size_t p = *pos;
+ size_t name_item_size = 0;
+
+ if (e) {
+ name_item_size = offsetof(struct kdbus_item, name.name) +
+ KDBUS_ALIGN8(strlen(e->name) + 1);
+
+ if (kdbus_ep_policy_check_see_access_unlocked(conn->ep, conn,
+ e->name) < 0)
+ return 0;
+ }
+
+ if (write) {
+ int ret;
+ struct kdbus_name_info info = {
+ .size = len,
+ .owner_id = c->id,
+ .conn_flags = c->flags,
+ };
+
+ info.size += name_item_size;
+
+ /* write record */
+ ret = kdbus_pool_slice_copy(slice, p, &info, len);
+ if (ret < 0)
+ return ret;
+ p += len;
+
+ /* append name */
+ if (e) {
+ /* fake the header of a kdbus_name item */
+ struct {
+ __u64 size;
+ __u64 type;
+ __u64 flags;
+ } h;
+ size_t nlen;
+
+ h.size = name_item_size;
+ h.type = KDBUS_ITEM_OWNED_NAME;
+ h.flags = e->flags;
+
+ ret = kdbus_pool_slice_copy(slice, p, &h, sizeof(h));
+ if (ret < 0)
+ return ret;
+
+ p += sizeof(h);
+
+ nlen = name_item_size - sizeof(h);
+ ret = kdbus_pool_slice_copy(slice, p, e->name, nlen);
+ if (ret < 0)
+ return ret;
+
+ p += nlen;
+ }
+ } else {
+ p += len + name_item_size;
+ }
+
+ *pos = p;
+ return 0;
+}
+
+static int kdbus_name_list_all(struct kdbus_conn *conn, u64 flags,
+ struct kdbus_pool_slice *slice,
+ size_t *pos, bool write)
+{
+ struct kdbus_conn *c;
+ size_t p = *pos;
+ int ret, i;
+
+ hash_for_each(conn->ep->bus->conn_hash, i, c, hentry) {
+ bool added = false;
+
+ /* skip activators */
+ if (!(flags & KDBUS_NAME_LIST_ACTIVATORS) &&
+ kdbus_conn_is_activator(c))
+ continue;
+
+ /* all names the connection owns */
+ if (flags & (KDBUS_NAME_LIST_NAMES |
+ KDBUS_NAME_LIST_ACTIVATORS)) {
+ struct kdbus_name_entry *e;
+
+ mutex_lock(&c->lock);
+ list_for_each_entry(e, &c->names_list, conn_entry) {
+ struct kdbus_conn *a = e->activator;
+
+ if ((flags & KDBUS_NAME_LIST_ACTIVATORS) &&
+ a && a != c) {
+ ret = kdbus_name_list_write(conn, a,
+ slice, &p, e, write);
+ if (ret < 0) {
+ mutex_unlock(&c->lock);
+ return ret;
+ }
+
+ added = true;
+ }
+
+ if (flags & KDBUS_NAME_LIST_NAMES ||
+ kdbus_conn_is_activator(c)) {
+ ret = kdbus_name_list_write(conn, c,
+ slice, &p, e, write);
+ if (ret < 0) {
+ mutex_unlock(&c->lock);
+ return ret;
+ }
+
+ added = true;
+ }
+ }
+ mutex_unlock(&c->lock);
+ }
+
+ /* queue of names the connection is currently waiting for */
+ if (flags & KDBUS_NAME_LIST_QUEUED) {
+ struct kdbus_name_queue_item *q;
+
+ mutex_lock(&c->lock);
+ list_for_each_entry(q, &c->names_queue_list,
+ conn_entry) {
+ ret = kdbus_name_list_write(conn, c,
+ slice, &p, q->entry, write);
+ if (ret < 0) {
+ mutex_unlock(&c->lock);
+ return ret;
+ }
+
+ added = true;
+ }
+ mutex_unlock(&c->lock);
+ }
+
+ /* nothing added so far, just add the unique ID */
+ if (!added && flags & KDBUS_NAME_LIST_UNIQUE) {
+ ret = kdbus_name_list_write(conn, c,
+ slice, &p, NULL, write);
+ if (ret < 0)
+ return ret;
+ }
+ }
+
+ *pos = p;
+ return 0;
+}
+
+/**
+ * kdbus_cmd_name_list() - list names of a connection
+ * @reg: The name registry
+ * @conn: The connection holding the name entries
+ * @cmd: The command as passed in by the ioctl
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int kdbus_cmd_name_list(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn,
+ struct kdbus_cmd_name_list *cmd)
+{
+ struct kdbus_policy_db *policy_db;
+ struct kdbus_name_list list = {};
+ struct kdbus_pool_slice *slice;
+ size_t pos;
+ int ret;
+
+ policy_db = &conn->ep->policy_db;
+
+ /* lock order: domain -> bus -> ep -> names -> conn */
+ down_read(&reg->rwlock);
+ down_read(&conn->ep->bus->conn_rwlock);
+ down_read(&policy_db->entries_rwlock);
+
+ /* size of header + records */
+ pos = sizeof(struct kdbus_name_list);
+ ret = kdbus_name_list_all(conn, cmd->flags, NULL, &pos, false);
+ if (ret < 0)
+ goto exit_unlock;
+
+ slice = kdbus_pool_slice_alloc(conn->pool, pos);
+ if (IS_ERR(slice)) {
+ ret = PTR_ERR(slice);
+ goto exit_unlock;
+ }
+
+ /* copy the header, specifying the overall size */
+ list.size = pos;
+ ret = kdbus_pool_slice_copy(slice, 0, &list, sizeof(list));
+ if (ret < 0)
+ goto exit_pool_free;
+
+ /* copy the records */
+ pos = sizeof(struct kdbus_name_list);
+ ret = kdbus_name_list_all(conn, cmd->flags, slice, &pos, true);
+ if (ret < 0)
+ goto exit_pool_free;
+
+ cmd->offset = kdbus_pool_slice_offset(slice);
+ kdbus_pool_slice_flush(slice);
+ kdbus_pool_slice_make_public(slice);
+
+exit_pool_free:
+ if (ret < 0)
+ kdbus_pool_slice_free(slice);
+exit_unlock:
+ up_read(&policy_db->entries_rwlock);
+ up_read(&conn->ep->bus->conn_rwlock);
+ up_read(&reg->rwlock);
+ return ret;
+}
diff --git a/ipc/kdbus/names.h b/ipc/kdbus/names.h
new file mode 100644
index 000000000000..a4d732a38782
--- /dev/null
+++ b/ipc/kdbus/names.h
@@ -0,0 +1,81 @@
+/*
+ * 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_NAMES_H
+#define __KDBUS_NAMES_H
+
+#include <linux/hashtable.h>
+#include <linux/rwsem.h>
+
+/**
+ * struct kdbus_name_registry - names registered for a bus
+ * @entries_hash: Map of entries
+ * @lock: Registry data lock
+ * @name_seq_last: Last used sequence number to assign to a name entry
+ */
+struct kdbus_name_registry {
+ DECLARE_HASHTABLE(entries_hash, 8);
+ struct rw_semaphore rwlock;
+ u64 name_seq_last;
+};
+
+/**
+ * struct kdbus_name_entry - well-know name entry
+ * @name: The well-known name
+ * @name_id: Sequence number of name entry to be able to uniquely
+ * identify a name over its registration lifetime
+ * @flags: KDBUS_NAME_* flags
+ * @queue_list: List of queued waiters for the well-known name
+ * @conn_entry: Entry in connection
+ * @hentry: Entry in registry map
+ * @conn: Connection owning the name
+ * @activator: Connection of the activator queuing incoming messages
+ */
+struct kdbus_name_entry {
+ char *name;
+ u64 name_id;
+ u64 flags;
+ struct list_head queue_list;
+ struct list_head conn_entry;
+ struct hlist_node hentry;
+ struct kdbus_conn *conn;
+ struct kdbus_conn *activator;
+};
+
+struct kdbus_name_registry *kdbus_name_registry_new(void);
+void kdbus_name_registry_free(struct kdbus_name_registry *reg);
+
+int kdbus_name_acquire(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn,
+ const char *name, u64 *flags);
+int kdbus_cmd_name_acquire(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn,
+ struct kdbus_cmd_name *cmd);
+int kdbus_cmd_name_release(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn,
+ const struct kdbus_cmd_name *cmd);
+int kdbus_cmd_name_list(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn,
+ struct kdbus_cmd_name_list *cmd);
+
+struct kdbus_name_entry *kdbus_name_lock(struct kdbus_name_registry *reg,
+ const char *name);
+struct kdbus_name_entry *kdbus_name_unlock(struct kdbus_name_registry *reg,
+ struct kdbus_name_entry *entry);
+
+void kdbus_name_remove_by_conn(struct kdbus_name_registry *reg,
+ struct kdbus_conn *conn);
+
+bool kdbus_name_is_valid(const char *p, bool allow_wildcard);
+
+#endif
--
2.1.3


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