// SPDX-License-Identifier: GPL-2.0-only
/* binder.c
 *
 * Android IPC Subsystem
 *
 * Copyright (C) 2007-2008 Google, Inc.
 */

/*
 * Locking overview
 *
 * There are 3 main spinlocks which must be acquired in the
 * order shown:
 *
 * 1) proc->outer_lock : protects binder_ref
 *    binder_proc_lock() and binder_proc_unlock() are
 *    used to acq/rel.
 * 2) node->lock : protects most fields of binder_node.
 *    binder_node_lock() and binder_node_unlock() are
 *    used to acq/rel
 * 3) proc->inner_lock : protects the thread and node lists
 *    (proc->threads, proc->waiting_threads, proc->nodes)
 *    and all todo lists associated with the binder_proc
 *    (proc->todo, thread->todo, proc->delivered_death and
 *    node->async_todo), as well as thread->transaction_stack
 *    binder_inner_proc_lock() and binder_inner_proc_unlock()
 *    are used to acq/rel
 *
 * Any lock under procA must never be nested under any lock at the same
 * level or below on procB.
 *
 * Functions that require a lock held on entry indicate which lock
 * in the suffix of the function name:
 *
 * foo_olocked() : requires node->outer_lock
 * foo_nlocked() : requires node->lock
 * foo_ilocked() : requires proc->inner_lock
 * foo_oilocked(): requires proc->outer_lock and proc->inner_lock
 * foo_nilocked(): requires node->lock and proc->inner_lock
 * ...
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/fdtable.h>
#include <linux/file.h>
#include <linux/freezer.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nsproxy.h>
#include <linux/poll.h>
#include <linux/debugfs.h>
#include <linux/rbtree.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/pid_namespace.h>
#include <linux/security.h>
#include <linux/spinlock.h>
#include <linux/ratelimit.h>
#include <linux/syscalls.h>
#include <linux/task_work.h>
#include <linux/sizes.h>

#include <uapi/linux/android/binder.h>

#include <asm/cacheflush.h>

#include "binder_internal.h"
#include "binder_trace.h"

static HLIST_HEAD(binder_deferred_list);
static DEFINE_MUTEX(binder_deferred_lock);

static HLIST_HEAD(binder_devices);
static HLIST_HEAD(binder_procs);
static DEFINE_MUTEX(binder_procs_lock);

static HLIST_HEAD(binder_dead_nodes);
static DEFINE_SPINLOCK(binder_dead_nodes_lock);

static struct dentry *binder_debugfs_dir_entry_root;
static struct dentry *binder_debugfs_dir_entry_proc;
static atomic_t binder_last_id;

static int proc_show(struct seq_file *m, void *unused);
DEFINE_SHOW_ATTRIBUTE(proc);

#define FORBIDDEN_MMAP_FLAGS                (VM_WRITE)

enum {
        BINDER_DEBUG_USER_ERROR             = 1U << 0,
        BINDER_DEBUG_FAILED_TRANSACTION     = 1U << 1,
        BINDER_DEBUG_DEAD_TRANSACTION       = 1U << 2,
        BINDER_DEBUG_OPEN_CLOSE             = 1U << 3,
        BINDER_DEBUG_DEAD_BINDER            = 1U << 4,
        BINDER_DEBUG_DEATH_NOTIFICATION     = 1U << 5,
        BINDER_DEBUG_READ_WRITE             = 1U << 6,
        BINDER_DEBUG_USER_REFS              = 1U << 7,
        BINDER_DEBUG_THREADS                = 1U << 8,
        BINDER_DEBUG_TRANSACTION            = 1U << 9,
        BINDER_DEBUG_TRANSACTION_COMPLETE   = 1U << 10,
        BINDER_DEBUG_FREE_BUFFER            = 1U << 11,
        BINDER_DEBUG_INTERNAL_REFS          = 1U << 12,
        BINDER_DEBUG_PRIORITY_CAP           = 1U << 13,
        BINDER_DEBUG_SPINLOCKS              = 1U << 14,
};
static uint32_t binder_debug_mask = BINDER_DEBUG_USER_ERROR |
        BINDER_DEBUG_FAILED_TRANSACTION | BINDER_DEBUG_DEAD_TRANSACTION;
module_param_named(debug_mask, binder_debug_mask, uint, 0644);

char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
module_param_named(devices, binder_devices_param, charp, 0444);

static DECLARE_WAIT_QUEUE_HEAD(binder_user_error_wait);
static int binder_stop_on_user_error;

static int binder_set_stop_on_user_error(const char *val,
                                         const struct kernel_param *kp)
{
        int ret;

        ret = param_set_int(val, kp);
        if (binder_stop_on_user_error < 2)
                wake_up(&binder_user_error_wait);
        return ret;
}
module_param_call(stop_on_user_error, binder_set_stop_on_user_error,
        param_get_int, &binder_stop_on_user_error, 0644);

#define binder_debug(mask, x...) \
        do { \
                if (binder_debug_mask & mask) \
                        pr_info_ratelimited(x); \
        } while (0)

#define binder_user_error(x...) \
        do { \
                if (binder_debug_mask & BINDER_DEBUG_USER_ERROR) \
                        pr_info_ratelimited(x); \
                if (binder_stop_on_user_error) \
                        binder_stop_on_user_error = 2; \
        } while (0)

#define to_flat_binder_object(hdr) \
        container_of(hdr, struct flat_binder_object, hdr)

#define to_binder_fd_object(hdr) container_of(hdr, struct binder_fd_object, hdr)

#define to_binder_buffer_object(hdr) \
        container_of(hdr, struct binder_buffer_object, hdr)

#define to_binder_fd_array_object(hdr) \
        container_of(hdr, struct binder_fd_array_object, hdr)

static struct binder_stats binder_stats;

static inline void binder_stats_deleted(enum binder_stat_types type)
{
        atomic_inc(&binder_stats.obj_deleted[type]);
}

static inline void binder_stats_created(enum binder_stat_types type)
{
        atomic_inc(&binder_stats.obj_created[type]);
}

struct binder_transaction_log binder_transaction_log;
struct binder_transaction_log binder_transaction_log_failed;

static struct binder_transaction_log_entry *binder_transaction_log_add(
        struct binder_transaction_log *log)
{
        struct binder_transaction_log_entry *e;
        unsigned int cur = atomic_inc_return(&log->cur);

        if (cur >= ARRAY_SIZE(log->entry))
                log->full = true;
        e = &log->entry[cur % ARRAY_SIZE(log->entry)];
        WRITE_ONCE(e->debug_id_done, 0);
        /*
         * write-barrier to synchronize access to e->debug_id_done.
         * We make sure the initialized 0 value is seen before
         * memset() other fields are zeroed by memset.
         */
        smp_wmb();
        memset(e, 0, sizeof(*e));
        return e;
}

enum binder_deferred_state {
        BINDER_DEFERRED_FLUSH        = 0x01,
        BINDER_DEFERRED_RELEASE      = 0x02,
};

enum {
        BINDER_LOOPER_STATE_REGISTERED  = 0x01,
        BINDER_LOOPER_STATE_ENTERED     = 0x02,
        BINDER_LOOPER_STATE_EXITED      = 0x04,
        BINDER_LOOPER_STATE_INVALID     = 0x08,
        BINDER_LOOPER_STATE_WAITING     = 0x10,
        BINDER_LOOPER_STATE_POLL        = 0x20,
};

/**
 * binder_proc_lock() - Acquire outer lock for given binder_proc
 * @proc:         struct binder_proc to acquire
 *
 * Acquires proc->outer_lock. Used to protect binder_ref
 * structures associated with the given proc.
 */
#define binder_proc_lock(proc) _binder_proc_lock(proc, __LINE__)
static void
_binder_proc_lock(struct binder_proc *proc, int line)
        __acquires(&proc->outer_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_lock(&proc->outer_lock);
}

/**
 * binder_proc_unlock() - Release spinlock for given binder_proc
 * @proc:         struct binder_proc to acquire
 *
 * Release lock acquired via binder_proc_lock()
 */
#define binder_proc_unlock(_proc) _binder_proc_unlock(_proc, __LINE__)
static void
_binder_proc_unlock(struct binder_proc *proc, int line)
        __releases(&proc->outer_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_unlock(&proc->outer_lock);
}

/**
 * binder_inner_proc_lock() - Acquire inner lock for given binder_proc
 * @proc:         struct binder_proc to acquire
 *
 * Acquires proc->inner_lock. Used to protect todo lists
 */
#define binder_inner_proc_lock(proc) _binder_inner_proc_lock(proc, __LINE__)
static void
_binder_inner_proc_lock(struct binder_proc *proc, int line)
        __acquires(&proc->inner_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_lock(&proc->inner_lock);
}

/**
 * binder_inner_proc_unlock() - Release inner lock for given binder_proc
 * @proc:         struct binder_proc to acquire
 *
 * Release lock acquired via binder_inner_proc_lock()
 */
#define binder_inner_proc_unlock(proc) _binder_inner_proc_unlock(proc, __LINE__)
static void
_binder_inner_proc_unlock(struct binder_proc *proc, int line)
        __releases(&proc->inner_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_unlock(&proc->inner_lock);
}

/**
 * binder_node_lock() - Acquire spinlock for given binder_node
 * @node:         struct binder_node to acquire
 *
 * Acquires node->lock. Used to protect binder_node fields
 */
#define binder_node_lock(node) _binder_node_lock(node, __LINE__)
static void
_binder_node_lock(struct binder_node *node, int line)
        __acquires(&node->lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_lock(&node->lock);
}

/**
 * binder_node_unlock() - Release spinlock for given binder_proc
 * @node:         struct binder_node to acquire
 *
 * Release lock acquired via binder_node_lock()
 */
#define binder_node_unlock(node) _binder_node_unlock(node, __LINE__)
static void
_binder_node_unlock(struct binder_node *node, int line)
        __releases(&node->lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_unlock(&node->lock);
}

/**
 * binder_node_inner_lock() - Acquire node and inner locks
 * @node:         struct binder_node to acquire
 *
 * Acquires node->lock. If node->proc also acquires
 * proc->inner_lock. Used to protect binder_node fields
 */
#define binder_node_inner_lock(node) _binder_node_inner_lock(node, __LINE__)
static void
_binder_node_inner_lock(struct binder_node *node, int line)
        __acquires(&node->lock) __acquires(&node->proc->inner_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_lock(&node->lock);
        if (node->proc)
                binder_inner_proc_lock(node->proc);
        else
                /* annotation for sparse */
                __acquire(&node->proc->inner_lock);
}

/**
 * binder_node_unlock() - Release node and inner locks
 * @node:         struct binder_node to acquire
 *
 * Release lock acquired via binder_node_lock()
 */
#define binder_node_inner_unlock(node) _binder_node_inner_unlock(node, __LINE__)
static void
_binder_node_inner_unlock(struct binder_node *node, int line)
        __releases(&node->lock) __releases(&node->proc->inner_lock)
{
        struct binder_proc *proc = node->proc;

        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        if (proc)
                binder_inner_proc_unlock(proc);
        else
                /* annotation for sparse */
                __release(&node->proc->inner_lock);
        spin_unlock(&node->lock);
}

static bool binder_worklist_empty_ilocked(struct list_head *list)
{
        return list_empty(list);
}

/**
 * binder_worklist_empty() - Check if no items on the work list
 * @proc:       binder_proc associated with list
 * @list:       list to check
 *
 * Return: true if there are no items on list, else false
 */
static bool binder_worklist_empty(struct binder_proc *proc,
                                  struct list_head *list)
{
        bool ret;

        binder_inner_proc_lock(proc);
        ret = binder_worklist_empty_ilocked(list);
        binder_inner_proc_unlock(proc);
        return ret;
}

/**
 * binder_enqueue_work_ilocked() - Add an item to the work list
 * @work:         struct binder_work to add to list
 * @target_list:  list to add work to
 *
 * Adds the work to the specified list. Asserts that work
 * is not already on a list.
 *
 * Requires the proc->inner_lock to be held.
 */
static void
binder_enqueue_work_ilocked(struct binder_work *work,
                           struct list_head *target_list)
{
        BUG_ON(target_list == NULL);
        BUG_ON(work->entry.next && !list_empty(&work->entry));
        list_add_tail(&work->entry, target_list);
}

/**
 * binder_enqueue_deferred_thread_work_ilocked() - Add deferred thread work
 * @thread:       thread to queue work to
 * @work:         struct binder_work to add to list
 *
 * Adds the work to the todo list of the thread. Doesn't set the process_todo
 * flag, which means that (if it wasn't already set) the thread will go to
 * sleep without handling this work when it calls read.
 *
 * Requires the proc->inner_lock to be held.
 */
static void
binder_enqueue_deferred_thread_work_ilocked(struct binder_thread *thread,
                                            struct binder_work *work)
{
        WARN_ON(!list_empty(&thread->waiting_thread_node));
        binder_enqueue_work_ilocked(work, &thread->todo);
}

/**
 * binder_enqueue_thread_work_ilocked() - Add an item to the thread work list
 * @thread:       thread to queue work to
 * @work:         struct binder_work to add to list
 *
 * Adds the work to the todo list of the thread, and enables processing
 * of the todo queue.
 *
 * Requires the proc->inner_lock to be held.
 */
static void
binder_enqueue_thread_work_ilocked(struct binder_thread *thread,
                                   struct binder_work *work)
{
        WARN_ON(!list_empty(&thread->waiting_thread_node));
        binder_enqueue_work_ilocked(work, &thread->todo);
        thread->process_todo = true;
}

/**
 * binder_enqueue_thread_work() - Add an item to the thread work list
 * @thread:       thread to queue work to
 * @work:         struct binder_work to add to list
 *
 * Adds the work to the todo list of the thread, and enables processing
 * of the todo queue.
 */
static void
binder_enqueue_thread_work(struct binder_thread *thread,
                           struct binder_work *work)
{
        binder_inner_proc_lock(thread->proc);
        binder_enqueue_thread_work_ilocked(thread, work);
        binder_inner_proc_unlock(thread->proc);
}

static void
binder_dequeue_work_ilocked(struct binder_work *work)
{
        list_del_init(&work->entry);
}

/**
 * binder_dequeue_work() - Removes an item from the work list
 * @proc:         binder_proc associated with list
 * @work:         struct binder_work to remove from list
 *
 * Removes the specified work item from whatever list it is on.
 * Can safely be called if work is not on any list.
 */
static void
binder_dequeue_work(struct binder_proc *proc, struct binder_work *work)
{
        binder_inner_proc_lock(proc);
        binder_dequeue_work_ilocked(work);
        binder_inner_proc_unlock(proc);
}

static struct binder_work *binder_dequeue_work_head_ilocked(
                                        struct list_head *list)
{
        struct binder_work *w;

        w = list_first_entry_or_null(list, struct binder_work, entry);
        if (w)
                list_del_init(&w->entry);
        return w;
}

static void
binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer);
static void binder_free_thread(struct binder_thread *thread);
static void binder_free_proc(struct binder_proc *proc);
static void binder_inc_node_tmpref_ilocked(struct binder_node *node);

static bool binder_has_work_ilocked(struct binder_thread *thread,
                                    bool do_proc_work)
{
        return thread->process_todo ||
                thread->looper_need_return ||
                (do_proc_work &&
                 !binder_worklist_empty_ilocked(&thread->proc->todo));
}

static bool binder_has_work(struct binder_thread *thread, bool do_proc_work)
{
        bool has_work;

        binder_inner_proc_lock(thread->proc);
        has_work = binder_has_work_ilocked(thread, do_proc_work);
        binder_inner_proc_unlock(thread->proc);

        return has_work;
}

static bool binder_available_for_proc_work_ilocked(struct binder_thread *thread)
{
        return !thread->transaction_stack &&
                binder_worklist_empty_ilocked(&thread->todo) &&
                (thread->looper & (BINDER_LOOPER_STATE_ENTERED |
                                   BINDER_LOOPER_STATE_REGISTERED));
}

static void binder_wakeup_poll_threads_ilocked(struct binder_proc *proc,
                                               bool sync)
{
        struct rb_node *n;
        struct binder_thread *thread;

        for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n)) {
                thread = rb_entry(n, struct binder_thread, rb_node);
                if (thread->looper & BINDER_LOOPER_STATE_POLL &&
                    binder_available_for_proc_work_ilocked(thread)) {
                        if (sync)
                                wake_up_interruptible_sync(&thread->wait);
                        else
                                wake_up_interruptible(&thread->wait);
                }
        }
}

/**
 * binder_select_thread_ilocked() - selects a thread for doing proc work.
 * @proc:       process to select a thread from
 *
 * Note that calling this function moves the thread off the waiting_threads
 * list, so it can only be woken up by the caller of this function, or a
 * signal. Therefore, callers *should* always wake up the thread this function
 * returns.
 *
 * Return:      If there's a thread currently waiting for process work,
 *              returns that thread. Otherwise returns NULL.
 */
static struct binder_thread *
binder_select_thread_ilocked(struct binder_proc *proc)
{
        struct binder_thread *thread;

        assert_spin_locked(&proc->inner_lock);
        thread = list_first_entry_or_null(&proc->waiting_threads,
                                          struct binder_thread,
                                          waiting_thread_node);

        if (thread)
                list_del_init(&thread->waiting_thread_node);

        return thread;
}

/**
 * binder_wakeup_thread_ilocked() - wakes up a thread for doing proc work.
 * @proc:       process to wake up a thread in
 * @thread:     specific thread to wake-up (may be NULL)
 * @sync:       whether to do a synchronous wake-up
 *
 * This function wakes up a thread in the @proc process.
 * The caller may provide a specific thread to wake-up in
 * the @thread parameter. If @thread is NULL, this function
 * will wake up threads that have called poll().
 *
 * Note that for this function to work as expected, callers
 * should first call binder_select_thread() to find a thread
 * to handle the work (if they don't have a thread already),
 * and pass the result into the @thread parameter.
 */
static void binder_wakeup_thread_ilocked(struct binder_proc *proc,
                                         struct binder_thread *thread,
                                         bool sync)
{
        assert_spin_locked(&proc->inner_lock);

        if (thread) {
                if (sync)
                        wake_up_interruptible_sync(&thread->wait);
                else
                        wake_up_interruptible(&thread->wait);
                return;
        }

        /* Didn't find a thread waiting for proc work; this can happen
         * in two scenarios:
         * 1. All threads are busy handling transactions
         *    In that case, one of those threads should call back into
         *    the kernel driver soon and pick up this work.
         * 2. Threads are using the (e)poll interface, in which case
         *    they may be blocked on the waitqueue without having been
         *    added to waiting_threads. For this case, we just iterate
         *    over all threads not handling transaction work, and
         *    wake them all up. We wake all because we don't know whether
         *    a thread that called into (e)poll is handling non-binder
         *    work currently.
         */
        binder_wakeup_poll_threads_ilocked(proc, sync);
}

static void binder_wakeup_proc_ilocked(struct binder_proc *proc)
{
        struct binder_thread *thread = binder_select_thread_ilocked(proc);

        binder_wakeup_thread_ilocked(proc, thread, /* sync = */false);
}

static void binder_set_nice(long nice)
{
        long min_nice;

        if (can_nice(current, nice)) {
                set_user_nice(current, nice);
                return;
        }
        min_nice = rlimit_to_nice(rlimit(RLIMIT_NICE));
        binder_debug(BINDER_DEBUG_PRIORITY_CAP,
                     "%d: nice value %ld not allowed use %ld instead\n",
                      current->pid, nice, min_nice);
        set_user_nice(current, min_nice);
        if (min_nice <= MAX_NICE)
                return;
        binder_user_error("%d RLIMIT_NICE not set\n", current->pid);
}

static struct binder_node *binder_get_node_ilocked(struct binder_proc *proc,
                                                   binder_uintptr_t ptr)
{
        struct rb_node *n = proc->nodes.rb_node;
        struct binder_node *node;

        assert_spin_locked(&proc->inner_lock);

        while (n) {
                node = rb_entry(n, struct binder_node, rb_node);

                if (ptr < node->ptr)
                        n = n->rb_left;
                else if (ptr > node->ptr)
                        n = n->rb_right;
                else {
                        /*
                         * take an implicit weak reference
                         * to ensure node stays alive until
                         * call to binder_put_node()
                         */
                        binder_inc_node_tmpref_ilocked(node);
                        return node;
                }
        }
        return NULL;
}

static struct binder_node *binder_get_node(struct binder_proc *proc,
                                           binder_uintptr_t ptr)
{
        struct binder_node *node;

        binder_inner_proc_lock(proc);
        node = binder_get_node_ilocked(proc, ptr);
        binder_inner_proc_unlock(proc);
        return node;
}

static struct binder_node *binder_init_node_ilocked(
                                                struct binder_proc *proc,
                                                struct binder_node *new_node,
                                                struct flat_binder_object *fp)
{
        struct rb_node **p = &proc->nodes.rb_node;
        struct rb_node *parent = NULL;
        struct binder_node *node;
        binder_uintptr_t ptr = fp ? fp->binder : 0;
        binder_uintptr_t cookie = fp ? fp->cookie : 0;
        __u32 flags = fp ? fp->flags : 0;

        assert_spin_locked(&proc->inner_lock);

        while (*p) {

                parent = *p;
                node = rb_entry(parent, struct binder_node, rb_node);

                if (ptr < node->ptr)
                        p = &(*p)->rb_left;
                else if (ptr > node->ptr)
                        p = &(*p)->rb_right;
                else {
                        /*
                         * A matching node is already in
                         * the rb tree. Abandon the init
                         * and return it.
                         */
                        binder_inc_node_tmpref_ilocked(node);
                        return node;
                }
        }
        node = new_node;
        binder_stats_created(BINDER_STAT_NODE);
        node->tmp_refs++;
        rb_link_node(&node->rb_node, parent, p);
        rb_insert_color(&node->rb_node, &proc->nodes);
        node->debug_id = atomic_inc_return(&binder_last_id);
        node->proc = proc;
        node->ptr = ptr;
        node->cookie = cookie;
        node->work.type = BINDER_WORK_NODE;
        node->min_priority = flags & FLAT_BINDER_FLAG_PRIORITY_MASK;
        node->accept_fds = !!(flags & FLAT_BINDER_FLAG_ACCEPTS_FDS);
        node->txn_security_ctx = !!(flags & FLAT_BINDER_FLAG_TXN_SECURITY_CTX);
        spin_lock_init(&node->lock);
        INIT_LIST_HEAD(&node->work.entry);
        INIT_LIST_HEAD(&node->async_todo);
        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                     "%d:%d node %d u%016llx c%016llx created\n",
                     proc->pid, current->pid, node->debug_id,
                     (u64)node->ptr, (u64)node->cookie);

        return node;
}

static struct binder_node *binder_new_node(struct binder_proc *proc,
                                           struct flat_binder_object *fp)
{
        struct binder_node *node;
        struct binder_node *new_node = kzalloc(sizeof(*node), GFP_KERNEL);

        if (!new_node)
                return NULL;
        binder_inner_proc_lock(proc);
        node = binder_init_node_ilocked(proc, new_node, fp);
        binder_inner_proc_unlock(proc);
        if (node != new_node)
                /*
                 * The node was already added by another thread
                 */
                kfree(new_node);

        return node;
}

static void binder_free_node(struct binder_node *node)
{
        kfree(node);
        binder_stats_deleted(BINDER_STAT_NODE);
}

static int binder_inc_node_nilocked(struct binder_node *node, int strong,
                                    int internal,
                                    struct list_head *target_list)
{
        struct binder_proc *proc = node->proc;

        assert_spin_locked(&node->lock);
        if (proc)
                assert_spin_locked(&proc->inner_lock);
        if (strong) {
                if (internal) {
                        if (target_list == NULL &&
                            node->internal_strong_refs == 0 &&
                            !(node->proc &&
                              node == node->proc->context->binder_context_mgr_node &&
                              node->has_strong_ref)) {
                                pr_err("invalid inc strong node for %d\n",
                                        node->debug_id);
                                return -EINVAL;
                        }
                        node->internal_strong_refs++;
                } else
                        node->local_strong_refs++;
                if (!node->has_strong_ref && target_list) {
                        struct binder_thread *thread = container_of(target_list,
                                                    struct binder_thread, todo);
                        binder_dequeue_work_ilocked(&node->work);
                        BUG_ON(&thread->todo != target_list);
                        binder_enqueue_deferred_thread_work_ilocked(thread,
                                                                   &node->work);
                }
        } else {
                if (!internal)
                        node->local_weak_refs++;
                if (!node->has_weak_ref && list_empty(&node->work.entry)) {
                        if (target_list == NULL) {
                                pr_err("invalid inc weak node for %d\n",
                                        node->debug_id);
                                return -EINVAL;
                        }
                        /*
                         * See comment above
                         */
                        binder_enqueue_work_ilocked(&node->work, target_list);
                }
        }
        return 0;
}

static int binder_inc_node(struct binder_node *node, int strong, int internal,
                           struct list_head *target_list)
{
        int ret;

        binder_node_inner_lock(node);
        ret = binder_inc_node_nilocked(node, strong, internal, target_list);
        binder_node_inner_unlock(node);

        return ret;
}

static bool binder_dec_node_nilocked(struct binder_node *node,
                                     int strong, int internal)
{
        struct binder_proc *proc = node->proc;

        assert_spin_locked(&node->lock);
        if (proc)
                assert_spin_locked(&proc->inner_lock);
        if (strong) {
                if (internal)
                        node->internal_strong_refs--;
                else
                        node->local_strong_refs--;
                if (node->local_strong_refs || node->internal_strong_refs)
                        return false;
        } else {
                if (!internal)
                        node->local_weak_refs--;
                if (node->local_weak_refs || node->tmp_refs ||
                                !hlist_empty(&node->refs))
                        return false;
        }

        if (proc && (node->has_strong_ref || node->has_weak_ref)) {
                if (list_empty(&node->work.entry)) {
                        binder_enqueue_work_ilocked(&node->work, &proc->todo);
                        binder_wakeup_proc_ilocked(proc);
                }
        } else {
                if (hlist_empty(&node->refs) && !node->local_strong_refs &&
                    !node->local_weak_refs && !node->tmp_refs) {
                        if (proc) {
                                binder_dequeue_work_ilocked(&node->work);
                                rb_erase(&node->rb_node, &proc->nodes);
                                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                             "refless node %d deleted\n",
                                             node->debug_id);
                        } else {
                                BUG_ON(!list_empty(&node->work.entry));
                                spin_lock(&binder_dead_nodes_lock);
                                /*
                                 * tmp_refs could have changed so
                                 * check it again
                                 */
                                if (node->tmp_refs) {
                                        spin_unlock(&binder_dead_nodes_lock);
                                        return false;
                                }
                                hlist_del(&node->dead_node);
                                spin_unlock(&binder_dead_nodes_lock);
                                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                             "dead node %d deleted\n",
                                             node->debug_id);
                        }
                        return true;
                }
        }
        return false;
}

static void binder_dec_node(struct binder_node *node, int strong, int internal)
{
        bool free_node;

        binder_node_inner_lock(node);
        free_node = binder_dec_node_nilocked(node, strong, internal);
        binder_node_inner_unlock(node);
        if (free_node)
                binder_free_node(node);
}

static void binder_inc_node_tmpref_ilocked(struct binder_node *node)
{
        /*
         * No call to binder_inc_node() is needed since we
         * don't need to inform userspace of any changes to
         * tmp_refs
         */
        node->tmp_refs++;
}

/**
 * binder_inc_node_tmpref() - take a temporary reference on node
 * @node:       node to reference
 *
 * Take reference on node to prevent the node from being freed
 * while referenced only by a local variable. The inner lock is
 * needed to serialize with the node work on the queue (which
 * isn't needed after the node is dead). If the node is dead
 * (node->proc is NULL), use binder_dead_nodes_lock to protect
 * node->tmp_refs against dead-node-only cases where the node
 * lock cannot be acquired (eg traversing the dead node list to
 * print nodes)
 */
static void binder_inc_node_tmpref(struct binder_node *node)
{
        binder_node_lock(node);
        if (node->proc)
                binder_inner_proc_lock(node->proc);
        else
                spin_lock(&binder_dead_nodes_lock);
        binder_inc_node_tmpref_ilocked(node);
        if (node->proc)
                binder_inner_proc_unlock(node->proc);
        else
                spin_unlock(&binder_dead_nodes_lock);
        binder_node_unlock(node);
}

/**
 * binder_dec_node_tmpref() - remove a temporary reference on node
 * @node:       node to reference
 *
 * Release temporary reference on node taken via binder_inc_node_tmpref()
 */
static void binder_dec_node_tmpref(struct binder_node *node)
{
        bool free_node;

        binder_node_inner_lock(node);
        if (!node->proc)
                spin_lock(&binder_dead_nodes_lock);
        else
                __acquire(&binder_dead_nodes_lock);
        node->tmp_refs--;
        BUG_ON(node->tmp_refs < 0);
        if (!node->proc)
                spin_unlock(&binder_dead_nodes_lock);
        else
                __release(&binder_dead_nodes_lock);
        /*
         * Call binder_dec_node() to check if all refcounts are 0
         * and cleanup is needed. Calling with strong=0 and internal=1
         * causes no actual reference to be released in binder_dec_node().
         * If that changes, a change is needed here too.
         */
        free_node = binder_dec_node_nilocked(node, 0, 1);
        binder_node_inner_unlock(node);
        if (free_node)
                binder_free_node(node);
}

static void binder_put_node(struct binder_node *node)
{
        binder_dec_node_tmpref(node);
}

static struct binder_ref *binder_get_ref_olocked(struct binder_proc *proc,
                                                 u32 desc, bool need_strong_ref)
{
        struct rb_node *n = proc->refs_by_desc.rb_node;
        struct binder_ref *ref;

        while (n) {
                ref = rb_entry(n, struct binder_ref, rb_node_desc);

                if (desc < ref->data.desc) {
                        n = n->rb_left;
                } else if (desc > ref->data.desc) {
                        n = n->rb_right;
                } else if (need_strong_ref && !ref->data.strong) {
                        binder_user_error("tried to use weak ref as strong ref\n");
                        return NULL;
                } else {
                        return ref;
                }
        }
        return NULL;
}

/**
 * binder_get_ref_for_node_olocked() - get the ref associated with given node
 * @proc:       binder_proc that owns the ref
 * @node:       binder_node of target
 * @new_ref:    newly allocated binder_ref to be initialized or %NULL
 *
 * Look up the ref for the given node and return it if it exists
 *
 * If it doesn't exist and the caller provides a newly allocated
 * ref, initialize the fields of the newly allocated ref and insert
 * into the given proc rb_trees and node refs list.
 *
 * Return:      the ref for node. It is possible that another thread
 *              allocated/initialized the ref first in which case the
 *              returned ref would be different than the passed-in

 *              new_ref. new_ref must be kfree'd by the caller in
 *              this case.
 */
static struct binder_ref *binder_get_ref_for_node_olocked(
                                        struct binder_proc *proc,
                                        struct binder_node *node,
                                        struct binder_ref *new_ref)
{
        struct binder_context *context = proc->context;
        struct rb_node **p = &proc->refs_by_node.rb_node;
        struct rb_node *parent = NULL;
        struct binder_ref *ref;
        struct rb_node *n;

        while (*p) {
                parent = *p;
                ref = rb_entry(parent, struct binder_ref, rb_node_node);

                if (node < ref->node)
                        p = &(*p)->rb_left;
                else if (node > ref->node)
                        p = &(*p)->rb_right;
                else
                        return ref;
        }
        if (!new_ref)
                return NULL;

        binder_stats_created(BINDER_STAT_REF);
        new_ref->data.debug_id = atomic_inc_return(&binder_last_id);
        new_ref->proc = proc;
        new_ref->node = node;
        rb_link_node(&new_ref->rb_node_node, parent, p);
        rb_insert_color(&new_ref->rb_node_node, &proc->refs_by_node);

        new_ref->data.desc = (node == context->binder_context_mgr_node) ? 0 : 1;
        for (n = rb_first(&proc->refs_by_desc); n != NULL; n = rb_next(n)) {
                ref = rb_entry(n, struct binder_ref, rb_node_desc);
                if (ref->data.desc > new_ref->data.desc)
                        break;
                new_ref->data.desc = ref->data.desc + 1;
        }

        p = &proc->refs_by_desc.rb_node;
        while (*p) {
                parent = *p;
                ref = rb_entry(parent, struct binder_ref, rb_node_desc);

                if (new_ref->data.desc < ref->data.desc)
                        p = &(*p)->rb_left;
                else if (new_ref->data.desc > ref->data.desc)
                        p = &(*p)->rb_right;
                else
                        BUG();
        }
        rb_link_node(&new_ref->rb_node_desc, parent, p);
        rb_insert_color(&new_ref->rb_node_desc, &proc->refs_by_desc);

        binder_node_lock(node);
        hlist_add_head(&new_ref->node_entry, &node->refs);

        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                     "%d new ref %d desc %d for node %d\n",
                      proc->pid, new_ref->data.debug_id, new_ref->data.desc,
                      node->debug_id);
        binder_node_unlock(node);
        return new_ref;
}

static void binder_cleanup_ref_olocked(struct binder_ref *ref)
{
        bool delete_node = false;

        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                     "%d delete ref %d desc %d for node %d\n",
                      ref->proc->pid, ref->data.debug_id, ref->data.desc,
                      ref->node->debug_id);

        rb_erase(&ref->rb_node_desc, &ref->proc->refs_by_desc);
        rb_erase(&ref->rb_node_node, &ref->proc->refs_by_node);

        binder_node_inner_lock(ref->node);
        if (ref->data.strong)
                binder_dec_node_nilocked(ref->node, 1, 1);

        hlist_del(&ref->node_entry);
        delete_node = binder_dec_node_nilocked(ref->node, 0, 1);
        binder_node_inner_unlock(ref->node);
        /*
         * Clear ref->node unless we want the caller to free the node
         */
        if (!delete_node) {
                /*
                 * The caller uses ref->node to determine
                 * whether the node needs to be freed. Clear
                 * it since the node is still alive.
                 */
                ref->node = NULL;
        }

        if (ref->death) {
                binder_debug(BINDER_DEBUG_DEAD_BINDER,
                             "%d delete ref %d desc %d has death notification\n",
                              ref->proc->pid, ref->data.debug_id,
                              ref->data.desc);
                binder_dequeue_work(ref->proc, &ref->death->work);
                binder_stats_deleted(BINDER_STAT_DEATH);
        }
        binder_stats_deleted(BINDER_STAT_REF);
}

/**
 * binder_inc_ref_olocked() - increment the ref for given handle
 * @ref:         ref to be incremented
 * @strong:      if true, strong increment, else weak
 * @target_list: list to queue node work on
 *
 * Increment the ref. @ref->proc->outer_lock must be held on entry
 *
 * Return: 0, if successful, else errno
 */
static int binder_inc_ref_olocked(struct binder_ref *ref, int strong,
                                  struct list_head *target_list)
{
        int ret;

        if (strong) {
                if (ref->data.strong == 0) {
                        ret = binder_inc_node(ref->node, 1, 1, target_list);
                        if (ret)
                                return ret;
                }
                ref->data.strong++;
        } else {
                if (ref->data.weak == 0) {
                        ret = binder_inc_node(ref->node, 0, 1, target_list);
                        if (ret)
                                return ret;
                }
                ref->data.weak++;
        }
        return 0;
}

/**
 * binder_dec_ref() - dec the ref for given handle
 * @ref:        ref to be decremented
 * @strong:     if true, strong decrement, else weak
 *
 * Decrement the ref.
 *
 * Return: true if ref is cleaned up and ready to be freed
 */
static bool binder_dec_ref_olocked(struct binder_ref *ref, int strong)
{
        if (strong) {
                if (ref->data.strong == 0) {
                        binder_user_error("%d invalid dec strong, ref %d desc %d s %d w %d\n",
                                          ref->proc->pid, ref->data.debug_id,
                                          ref->data.desc, ref->data.strong,
                                          ref->data.weak);
                        return false;
                }
                ref->data.strong--;
                if (ref->data.strong == 0)
                        binder_dec_node(ref->node, strong, 1);
        } else {
                if (ref->data.weak == 0) {
                        binder_user_error("%d invalid dec weak, ref %d desc %d s %d w %d\n",
                                          ref->proc->pid, ref->data.debug_id,
                                          ref->data.desc, ref->data.strong,
                                          ref->data.weak);
                        return false;
                }
                ref->data.weak--;
        }
        if (ref->data.strong == 0 && ref->data.weak == 0) {
                binder_cleanup_ref_olocked(ref);
                return true;
        }
        return false;
}

/**
 * binder_get_node_from_ref() - get the node from the given proc/desc
 * @proc:       proc containing the ref
 * @desc:       the handle associated with the ref
 * @need_strong_ref: if true, only return node if ref is strong
 * @rdata:      the id/refcount data for the ref
 *
 * Given a proc and ref handle, return the associated binder_node
 *
 * Return: a binder_node or NULL if not found or not strong when strong required
 */
static struct binder_node *binder_get_node_from_ref(
                struct binder_proc *proc,
                u32 desc, bool need_strong_ref,
                struct binder_ref_data *rdata)
{
        struct binder_node *node;
        struct binder_ref *ref;

        binder_proc_lock(proc);
        ref = binder_get_ref_olocked(proc, desc, need_strong_ref);
        if (!ref)
                goto err_no_ref;
        node = ref->node;
        /*
         * Take an implicit reference on the node to ensure
         * it stays alive until the call to binder_put_node()
         */
        binder_inc_node_tmpref(node);
        if (rdata)
                *rdata = ref->data;
        binder_proc_unlock(proc);

        return node;

err_no_ref:
        binder_proc_unlock(proc);
        return NULL;
}

/**
 * binder_free_ref() - free the binder_ref
 * @ref:        ref to free
 *
 * Free the binder_ref. Free the binder_node indicated by ref->node
 * (if non-NULL) and the binder_ref_death indicated by ref->death.
 */
static void binder_free_ref(struct binder_ref *ref)
{
        if (ref->node)
                binder_free_node(ref->node);
        kfree(ref->death);
        kfree(ref);
}

/**
 * binder_update_ref_for_handle() - inc/dec the ref for given handle
 * @proc:       proc containing the ref
 * @desc:       the handle associated with the ref
 * @increment:  true=inc reference, false=dec reference
 * @strong:     true=strong reference, false=weak reference
 * @rdata:      the id/refcount data for the ref
 *
 * Given a proc and ref handle, increment or decrement the ref
 * according to "increment" arg.
 *
 * Return: 0 if successful, else errno
 */
static int binder_update_ref_for_handle(struct binder_proc *proc,
                uint32_t desc, bool increment, bool strong,
                struct binder_ref_data *rdata)
{
        int ret = 0;
        struct binder_ref *ref;
        bool delete_ref = false;

        binder_proc_lock(proc);
        ref = binder_get_ref_olocked(proc, desc, strong);
        if (!ref) {
                ret = -EINVAL;
                goto err_no_ref;
        }
        if (increment)
                ret = binder_inc_ref_olocked(ref, strong, NULL);
        else
                delete_ref = binder_dec_ref_olocked(ref, strong);

        if (rdata)
                *rdata = ref->data;
        binder_proc_unlock(proc);

        if (delete_ref)
                binder_free_ref(ref);
        return ret;

err_no_ref:
        binder_proc_unlock(proc);
        return ret;
}

/**
 * binder_dec_ref_for_handle() - dec the ref for given handle
 * @proc:       proc containing the ref
 * @desc:       the handle associated with the ref
 * @strong:     true=strong reference, false=weak reference
 * @rdata:      the id/refcount data for the ref
 *
 * Just calls binder_update_ref_for_handle() to decrement the ref.
 *
 * Return: 0 if successful, else errno
 */
static int binder_dec_ref_for_handle(struct binder_proc *proc,
                uint32_t desc, bool strong, struct binder_ref_data *rdata)
{
        return binder_update_ref_for_handle(proc, desc, false, strong, rdata);
}


/**
 * binder_inc_ref_for_node() - increment the ref for given proc/node
 * @proc:        proc containing the ref
 * @node:        target node
 * @strong:      true=strong reference, false=weak reference
 * @target_list: worklist to use if node is incremented
 * @rdata:       the id/refcount data for the ref
 *
 * Given a proc and node, increment the ref. Create the ref if it
 * doesn't already exist
 *
 * Return: 0 if successful, else errno
 */
static int binder_inc_ref_for_node(struct binder_proc *proc,
                        struct binder_node *node,
                        bool strong,
                        struct list_head *target_list,
                        struct binder_ref_data *rdata)
{
        struct binder_ref *ref;
        struct binder_ref *new_ref = NULL;
        int ret = 0;

        binder_proc_lock(proc);
        ref = binder_get_ref_for_node_olocked(proc, node, NULL);
        if (!ref) {
                binder_proc_unlock(proc);
                new_ref = kzalloc(sizeof(*ref), GFP_KERNEL);
                if (!new_ref)
                        return -ENOMEM;
                binder_proc_lock(proc);
                ref = binder_get_ref_for_node_olocked(proc, node, new_ref);
        }
        ret = binder_inc_ref_olocked(ref, strong, target_list);
        *rdata = ref->data;
        binder_proc_unlock(proc);
        if (new_ref && ref != new_ref)
                /*
                 * Another thread created the ref first so
                 * free the one we allocated
                 */
                kfree(new_ref);
        return ret;
}

static void binder_pop_transaction_ilocked(struct binder_thread *target_thread,
                                           struct binder_transaction *t)
{
        BUG_ON(!target_thread);
        assert_spin_locked(&target_thread->proc->inner_lock);
        BUG_ON(target_thread->transaction_stack != t);
        BUG_ON(target_thread->transaction_stack->from != target_thread);
        target_thread->transaction_stack =
                target_thread->transaction_stack->from_parent;
        t->from = NULL;
}

/**
 * binder_thread_dec_tmpref() - decrement thread->tmp_ref
 * @thread:     thread to decrement
 *
 * A thread needs to be kept alive while being used to create or
 * handle a transaction. binder_get_txn_from() is used to safely
 * extract t->from from a binder_transaction and keep the thread
 * indicated by t->from from being freed. When done with that
 * binder_thread, this function is called to decrement the
 * tmp_ref and free if appropriate (thread has been released
 * and no transaction being processed by the driver)
 */
static void binder_thread_dec_tmpref(struct binder_thread *thread)
{
        /*
         * atomic is used to protect the counter value while
         * it cannot reach zero or thread->is_dead is false
         */
        binder_inner_proc_lock(thread->proc);
        atomic_dec(&thread->tmp_ref);
        if (thread->is_dead && !atomic_read(&thread->tmp_ref)) {
                binder_inner_proc_unlock(thread->proc);
                binder_free_thread(thread);
                return;
        }
        binder_inner_proc_unlock(thread->proc);
}

/**
 * binder_proc_dec_tmpref() - decrement proc->tmp_ref
 * @proc:       proc to decrement
 *
 * A binder_proc needs to be kept alive while being used to create or
 * handle a transaction. proc->tmp_ref is incremented when
 * creating a new transaction or the binder_proc is currently in-use
 * by threads that are being released. When done with the binder_proc,
 * this function is called to decrement the counter and free the
 * proc if appropriate (proc has been released, all threads have
 * been released and not currenly in-use to process a transaction).
 */
static void binder_proc_dec_tmpref(struct binder_proc *proc)
{
        binder_inner_proc_lock(proc);
        proc->tmp_ref--;
        if (proc->is_dead && RB_EMPTY_ROOT(&proc->threads) &&
                        !proc->tmp_ref) {
                binder_inner_proc_unlock(proc);
                binder_free_proc(proc);
                return;
        }
        binder_inner_proc_unlock(proc);
}

/**
 * binder_get_txn_from() - safely extract the "from" thread in transaction
 * @t:  binder transaction for t->from
 *
 * Atomically return the "from" thread and increment the tmp_ref
 * count for the thread to ensure it stays alive until
 * binder_thread_dec_tmpref() is called.
 *
 * Return: the value of t->from
 */
static struct binder_thread *binder_get_txn_from(
                struct binder_transaction *t)
{
        struct binder_thread *from;

        spin_lock(&t->lock);
        from = t->from;
        if (from)
                atomic_inc(&from->tmp_ref);
        spin_unlock(&t->lock);
        return from;
}

/**
 * binder_get_txn_from_and_acq_inner() - get t->from and acquire inner lock
 * @t:  binder transaction for t->from
 *
 * Same as binder_get_txn_from() except it also acquires the proc->inner_lock
 * to guarantee that the thread cannot be released while operating on it.
 * The caller must call binder_inner_proc_unlock() to release the inner lock
 * as well as call binder_dec_thread_txn() to release the reference.
 *
 * Return: the value of t->from
 */
static struct binder_thread *binder_get_txn_from_and_acq_inner(
                struct binder_transaction *t)
        __acquires(&t->from->proc->inner_lock)
{
        struct binder_thread *from;

        from = binder_get_txn_from(t);
        if (!from) {
                __acquire(&from->proc->inner_lock);
                return NULL;
        }
        binder_inner_proc_lock(from->proc);
        if (t->from) {
                BUG_ON(from != t->from);
                return from;
        }
        binder_inner_proc_unlock(from->proc);
        __acquire(&from->proc->inner_lock);
        binder_thread_dec_tmpref(from);
        return NULL;
}

/**
 * binder_free_txn_fixups() - free unprocessed fd fixups
 * @t:  binder transaction for t->from
 *
 * If the transaction is being torn down prior to being
 * processed by the target process, free all of the
 * fd fixups and fput the file structs. It is safe to
 * call this function after the fixups have been
 * processed -- in that case, the list will be empty.
 */
static void binder_free_txn_fixups(struct binder_transaction *t)
{
        struct binder_txn_fd_fixup *fixup, *tmp;

        list_for_each_entry_safe(fixup, tmp, &t->fd_fixups, fixup_entry) {
                fput(fixup->file);
                list_del(&fixup->fixup_entry);
                kfree(fixup);
        }
}

static void binder_txn_latency_free(struct binder_transaction *t)
{
        int from_proc, from_thread, to_proc, to_thread;

        spin_lock(&t->lock);
        from_proc = t->from ? t->from->proc->pid : 0;
        from_thread = t->from ? t->from->pid : 0;
        to_proc = t->to_proc ? t->to_proc->pid : 0;
        to_thread = t->to_thread ? t->to_thread->pid : 0;
        spin_unlock(&t->lock);

        trace_binder_txn_latency_free(t, from_proc, from_thread, to_proc, to_thread);
}

static void binder_free_transaction(struct binder_transaction *t)
{
        struct binder_proc *target_proc = t->to_proc;

        if (target_proc) {
                binder_inner_proc_lock(target_proc);
                target_proc->outstanding_txns--;
                if (target_proc->outstanding_txns < 0)
                        pr_warn("%s: Unexpected outstanding_txns %d\n",
                                __func__, target_proc->outstanding_txns);
                if (!target_proc->outstanding_txns && target_proc->is_frozen)
                        wake_up_interruptible_all(&target_proc->freeze_wait);
                if (t->buffer)
                        t->buffer->transaction = NULL;
                binder_inner_proc_unlock(target_proc);
        }
        if (trace_binder_txn_latency_free_enabled())
                binder_txn_latency_free(t);
        /*
         * If the transaction has no target_proc, then
         * t->buffer->transaction has already been cleared.
         */
        binder_free_txn_fixups(t);
        kfree(t);
        binder_stats_deleted(BINDER_STAT_TRANSACTION);
}

static void binder_send_failed_reply(struct binder_transaction *t,
                                     uint32_t error_code)
{
        struct binder_thread *target_thread;
        struct binder_transaction *next;

        BUG_ON(t->flags & TF_ONE_WAY);
        while (1) {
                target_thread = binder_get_txn_from_and_acq_inner(t);
                if (target_thread) {
                        binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                                     "send failed reply for transaction %d to %d:%d\n",
                                      t->debug_id,
                                      target_thread->proc->pid,
                                      target_thread->pid);

                        binder_pop_transaction_ilocked(target_thread, t);
                        if (target_thread->reply_error.cmd == BR_OK) {
                                target_thread->reply_error.cmd = error_code;
                                binder_enqueue_thread_work_ilocked(
                                        target_thread,
                                        &target_thread->reply_error.work);
                                wake_up_interruptible(&target_thread->wait);
                        } else {
                                /*
                                 * Cannot get here for normal operation, but
                                 * we can if multiple synchronous transactions
                                 * are sent without blocking for responses.
                                 * Just ignore the 2nd error in this case.
                                 */
                                pr_warn("Unexpected reply error: %u\n",
                                        target_thread->reply_error.cmd);
                        }
                        binder_inner_proc_unlock(target_thread->proc);
                        binder_thread_dec_tmpref(target_thread);
                        binder_free_transaction(t);
                        return;
                }
                __release(&target_thread->proc->inner_lock);
                next = t->from_parent;

                binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                             "send failed reply for transaction %d, target dead\n",
                             t->debug_id);

                binder_free_transaction(t);
                if (next == NULL) {
                        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                                     "reply failed, no target thread at root\n");
                        return;
                }
                t = next;
                binder_debug(BINDER_DEBUG_DEAD_BINDER,
                             "reply failed, no target thread -- retry %d\n",
                              t->debug_id);
        }
}

/**
 * binder_cleanup_transaction() - cleans up undelivered transaction
 * @t:          transaction that needs to be cleaned up
 * @reason:     reason the transaction wasn't delivered
 * @error_code: error to return to caller (if synchronous call)
 */
static void binder_cleanup_transaction(struct binder_transaction *t,
                                       const char *reason,
                                       uint32_t error_code)
{
        if (t->buffer->target_node && !(t->flags & TF_ONE_WAY)) {
                binder_send_failed_reply(t, error_code);
        } else {
                binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                        "undelivered transaction %d, %s\n",
                        t->debug_id, reason);
                binder_free_transaction(t);
        }
}

/**
 * binder_get_object() - gets object and checks for valid metadata
 * @proc:       binder_proc owning the buffer
 * @buffer:     binder_buffer that we're parsing.
 * @offset:     offset in the @buffer at which to validate an object.
 * @object:     struct binder_object to read into
 *
 * Return:      If there's a valid metadata object at @offset in @buffer, the
 *              size of that object. Otherwise, it returns zero. The object
 *              is read into the struct binder_object pointed to by @object.
 */
static size_t binder_get_object(struct binder_proc *proc,
                                struct binder_buffer *buffer,
                                unsigned long offset,
                                struct binder_object *object)
{
        size_t read_size;
        struct binder_object_header *hdr;
        size_t object_size = 0;

        read_size = min_t(size_t, sizeof(*object), buffer->data_size - offset);
        if (offset > buffer->data_size || read_size < sizeof(*hdr) ||
            binder_alloc_copy_from_buffer(&proc->alloc, object, buffer,
                                          offset, read_size))
                return 0;

        /* Ok, now see if we read a complete object. */
        hdr = &object->hdr;
        switch (hdr->type) {
        case BINDER_TYPE_BINDER:
        case BINDER_TYPE_WEAK_BINDER:
        case BINDER_TYPE_HANDLE:
        case BINDER_TYPE_WEAK_HANDLE:
                object_size = sizeof(struct flat_binder_object);
                break;
        case BINDER_TYPE_FD:
                object_size = sizeof(struct binder_fd_object);
                break;
        case BINDER_TYPE_PTR:
                object_size = sizeof(struct binder_buffer_object);
                break;
        case BINDER_TYPE_FDA:
                object_size = sizeof(struct binder_fd_array_object);
                break;
        default:
                return 0;
        }
        if (offset <= buffer->data_size - object_size &&
            buffer->data_size >= object_size)
                return object_size;
        else
                return 0;
}

/**
 * binder_validate_ptr() - validates binder_buffer_object in a binder_buffer.
 * @proc:       binder_proc owning the buffer
 * @b:          binder_buffer containing the object
 * @object:     struct binder_object to read into
 * @index:      index in offset array at which the binder_buffer_object is
 *              located
 * @start_offset: points to the start of the offset array
 * @object_offsetp: offset of @object read from @b
 * @num_valid:  the number of valid offsets in the offset array
 *
 * Return:      If @index is within the valid range of the offset array
 *              described by @start and @num_valid, and if there's a valid
 *              binder_buffer_object at the offset found in index @index
 *              of the offset array, that object is returned. Otherwise,
 *              %NULL is returned.
 *              Note that the offset found in index @index itself is not
 *              verified; this function assumes that @num_valid elements
 *              from @start were previously verified to have valid offsets.
 *              If @object_offsetp is non-NULL, then the offset within
 *              @b is written to it.
 */
static struct binder_buffer_object *binder_validate_ptr(
                                                struct binder_proc *proc,
                                                struct binder_buffer *b,
                                                struct binder_object *object,
                                                binder_size_t index,
                                                binder_size_t start_offset,
                                                binder_size_t *object_offsetp,
                                                binder_size_t num_valid)
{
        size_t object_size;
        binder_size_t object_offset;
        unsigned long buffer_offset;

        if (index >= num_valid)
                return NULL;

        buffer_offset = start_offset + sizeof(binder_size_t) * index;
        if (binder_alloc_copy_from_buffer(&proc->alloc, &object_offset,
                                          b, buffer_offset,
                                          sizeof(object_offset)))
                return NULL;
        object_size = binder_get_object(proc, b, object_offset, object);
        if (!object_size || object->hdr.type != BINDER_TYPE_PTR)
                return NULL;
        if (object_offsetp)
                *object_offsetp = object_offset;

        return &object->bbo;
}

/**
 * binder_validate_fixup() - validates pointer/fd fixups happen in order.
 * @proc:               binder_proc owning the buffer
 * @b:                  transaction buffer
 * @objects_start_offset: offset to start of objects buffer
 * @buffer_obj_offset:  offset to binder_buffer_object in which to fix up
 * @fixup_offset:       start offset in @buffer to fix up
 * @last_obj_offset:    offset to last binder_buffer_object that we fixed
 * @last_min_offset:    minimum fixup offset in object at @last_obj_offset
 *
 * Return:              %true if a fixup in buffer @buffer at offset @offset is
 *                      allowed.
 *
 * For safety reasons, we only allow fixups inside a buffer to happen
 * at increasing offsets; additionally, we only allow fixup on the last
 * buffer object that was verified, or one of its parents.
 *
 * Example of what is allowed:
 *
 * A
 *   B (parent = A, offset = 0)
 *   C (parent = A, offset = 16)
 *     D (parent = C, offset = 0)
 *   E (parent = A, offset = 32) // min_offset is 16 (C.parent_offset)
 *
 * Examples of what is not allowed:
 *
 * Decreasing offsets within the same parent:
 * A
 *   C (parent = A, offset = 16)
 *   B (parent = A, offset = 0) // decreasing offset within A
 *
 * Referring to a parent that wasn't the last object or any of its parents:
 * A
 *   B (parent = A, offset = 0)
 *   C (parent = A, offset = 0)
 *   C (parent = A, offset = 16)
 *     D (parent = B, offset = 0) // B is not A or any of A's parents
 */
static bool binder_validate_fixup(struct binder_proc *proc,
                                  struct binder_buffer *b,
                                  binder_size_t objects_start_offset,
                                  binder_size_t buffer_obj_offset,
                                  binder_size_t fixup_offset,
                                  binder_size_t last_obj_offset,
                                  binder_size_t last_min_offset)
{
        if (!last_obj_offset) {
                /* Nothing to fix up in */
                return false;
        }

        while (last_obj_offset != buffer_obj_offset) {
                unsigned long buffer_offset;
                struct binder_object last_object;
                struct binder_buffer_object *last_bbo;
                size_t object_size = binder_get_object(proc, b, last_obj_offset,
                                                       &last_object);
                if (object_size != sizeof(*last_bbo))
                        return false;

                last_bbo = &last_object.bbo;
                /*
                 * Safe to retrieve the parent of last_obj, since it
                 * was already previously verified by the driver.
                 */
                if ((last_bbo->flags & BINDER_BUFFER_FLAG_HAS_PARENT) == 0)
                        return false;
                last_min_offset = last_bbo->parent_offset + sizeof(uintptr_t);
                buffer_offset = objects_start_offset +
                        sizeof(binder_size_t) * last_bbo->parent;
                if (binder_alloc_copy_from_buffer(&proc->alloc,
                                                  &last_obj_offset,
                                                  b, buffer_offset,
                                                  sizeof(last_obj_offset)))
                        return false;
        }
        return (fixup_offset >= last_min_offset);
}

/**
 * struct binder_task_work_cb - for deferred close
 *
 * @twork:                callback_head for task work
 * @fd:                   fd to close
 *
 * Structure to pass task work to be handled after
 * returning from binder_ioctl() via task_work_add().
 */
struct binder_task_work_cb {
        struct callback_head twork;
        struct file *file;
};

/**
 * binder_do_fd_close() - close list of file descriptors
 * @twork:      callback head for task work
 *
 * It is not safe to call ksys_close() during the binder_ioctl()
 * function if there is a chance that binder's own file descriptor
 * might be closed. This is to meet the requirements for using
 * fdget() (see comments for __fget_light()). Therefore use
 * task_work_add() to schedule the close operation once we have
 * returned from binder_ioctl(). This function is a callback
 * for that mechanism and does the actual ksys_close() on the
 * given file descriptor.
 */
static void binder_do_fd_close(struct callback_head *twork)
{
        struct binder_task_work_cb *twcb = container_of(twork,
                        struct binder_task_work_cb, twork);

        fput(twcb->file);
        kfree(twcb);
}

/**
 * binder_deferred_fd_close() - schedule a close for the given file-descriptor
 * @fd:         file-descriptor to close
 *
 * See comments in binder_do_fd_close(). This function is used to schedule
 * a file-descriptor to be closed after returning from binder_ioctl().
 */
static void binder_deferred_fd_close(int fd)
{
        struct binder_task_work_cb *twcb;

        twcb = kzalloc(sizeof(*twcb), GFP_KERNEL);
        if (!twcb)
                return;
        init_task_work(&twcb->twork, binder_do_fd_close);
        close_fd_get_file(fd, &twcb->file);
        if (twcb->file) {
                filp_close(twcb->file, current->files);
                task_work_add(current, &twcb->twork, TWA_RESUME);
        } else {
                kfree(twcb);
        }
}

static void binder_transaction_buffer_release(struct binder_proc *proc,
                                              struct binder_buffer *buffer,
                                              binder_size_t failed_at,
                                              bool is_failure)
{
        int debug_id = buffer->debug_id;
        binder_size_t off_start_offset, buffer_offset, off_end_offset;

        binder_debug(BINDER_DEBUG_TRANSACTION,
                     "%d buffer release %d, size %zd-%zd, failed at %llx\n",
                     proc->pid, buffer->debug_id,
                     buffer->data_size, buffer->offsets_size,
                     (unsigned long long)failed_at);

        if (buffer->target_node)
                binder_dec_node(buffer->target_node, 1, 0);

        off_start_offset = ALIGN(buffer->data_size, sizeof(void *));
        off_end_offset = is_failure ? failed_at :
                                off_start_offset + buffer->offsets_size;
        for (buffer_offset = off_start_offset; buffer_offset < off_end_offset;
             buffer_offset += sizeof(binder_size_t)) {
                struct binder_object_header *hdr;
                size_t object_size = 0;
                struct binder_object object;
                binder_size_t object_offset;

                if (!binder_alloc_copy_from_buffer(&proc->alloc, &object_offset,
                                                   buffer, buffer_offset,
                                                   sizeof(object_offset)))
                        object_size = binder_get_object(proc, buffer,
                                                        object_offset, &object);
                if (object_size == 0) {
                        pr_err("transaction release %d bad object at offset %lld, size %zd\n",
                               debug_id, (u64)object_offset, buffer->data_size);
                        continue;
                }
                hdr = &object.hdr;
                switch (hdr->type) {
                case BINDER_TYPE_BINDER:
                case BINDER_TYPE_WEAK_BINDER: {
                        struct flat_binder_object *fp;
                        struct binder_node *node;

                        fp = to_flat_binder_object(hdr);
                        node = binder_get_node(proc, fp->binder);
                        if (node == NULL) {
                                pr_err("transaction release %d bad node %016llx\n",
                                       debug_id, (u64)fp->binder);
                                break;
                        }
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "        node %d u%016llx\n",
                                     node->debug_id, (u64)node->ptr);
                        binder_dec_node(node, hdr->type == BINDER_TYPE_BINDER,
                                        0);
                        binder_put_node(node);
                } break;
                case BINDER_TYPE_HANDLE:
                case BINDER_TYPE_WEAK_HANDLE: {
                        struct flat_binder_object *fp;
                        struct binder_ref_data rdata;
                        int ret;

                        fp = to_flat_binder_object(hdr);
                        ret = binder_dec_ref_for_handle(proc, fp->handle,
                                hdr->type == BINDER_TYPE_HANDLE, &rdata);

                        if (ret) {
                                pr_err("transaction release %d bad handle %d, ret = %d\n",
                                 debug_id, fp->handle, ret);
                                break;
                        }
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "        ref %d desc %d\n",
                                     rdata.debug_id, rdata.desc);
                } break;

                case BINDER_TYPE_FD: {
                        /*
                         * No need to close the file here since user-space
                         * closes it for for successfully delivered
                         * transactions. For transactions that weren't
                         * delivered, the new fd was never allocated so
                         * there is no need to close and the fput on the
                         * file is done when the transaction is torn
                         * down.
                         */
                } break;
                case BINDER_TYPE_PTR:
                        /*
                         * Nothing to do here, this will get cleaned up when the
                         * transaction buffer gets freed
                         */
                        break;
                case BINDER_TYPE_FDA: {
                        struct binder_fd_array_object *fda;
                        struct binder_buffer_object *parent;
                        struct binder_object ptr_object;
                        binder_size_t fda_offset;
                        size_t fd_index;
                        binder_size_t fd_buf_size;
                        binder_size_t num_valid;

                        if (proc->tsk != current->group_leader) {
                                /*
                                 * Nothing to do if running in sender context
                                 * The fd fixups have not been applied so no
                                 * fds need to be closed.
                                 */
                                continue;
                        }

                        num_valid = (buffer_offset - off_start_offset) /
                                                sizeof(binder_size_t);
                        fda = to_binder_fd_array_object(hdr);
                        parent = binder_validate_ptr(proc, buffer, &ptr_object,
                                                     fda->parent,
                                                     off_start_offset,
                                                     NULL,
                                                     num_valid);
                        if (!parent) {
                                pr_err("transaction release %d bad parent offset\n",
                                       debug_id);
                                continue;
                        }
                        fd_buf_size = sizeof(u32) * fda->num_fds;
                        if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
                                pr_err("transaction release %d invalid number of fds (%lld)\n",
                                       debug_id, (u64)fda->num_fds);
                                continue;
                        }
                        if (fd_buf_size > parent->length ||
                            fda->parent_offset > parent->length - fd_buf_size) {
                                /* No space for all file descriptors here. */
                                pr_err("transaction release %d not enough space for %lld fds in buffer\n",
                                       debug_id, (u64)fda->num_fds);
                                continue;
                        }
                        /*
                         * the source data for binder_buffer_object is visible
                         * to user-space and the @buffer element is the user
                         * pointer to the buffer_object containing the fd_array.
                         * Convert the address to an offset relative to
                         * the base of the transaction buffer.
                         */
                        fda_offset =

                            (parent->buffer - (uintptr_t)buffer->user_data) +
                            fda->parent_offset;
                        for (fd_index = 0; fd_index < fda->num_fds;
                             fd_index++) {
                                u32 fd;
                                int err;
                                binder_size_t offset = fda_offset +
                                        fd_index * sizeof(fd);

                                err = binder_alloc_copy_from_buffer(
                                                &proc->alloc, &fd, buffer,
                                                offset, sizeof(fd));
                                WARN_ON(err);
                                if (!err)
                                        binder_deferred_fd_close(fd);
                        }
                } break;
                default:
                        pr_err("transaction release %d bad object type %x\n",
                                debug_id, hdr->type);
                        break;
                }
        }
}

static int binder_translate_binder(struct flat_binder_object *fp,
                                   struct binder_transaction *t,
                                   struct binder_thread *thread)
{
        struct binder_node *node;
        struct binder_proc *proc = thread->proc;
        struct binder_proc *target_proc = t->to_proc;
        struct binder_ref_data rdata;
        int ret = 0;

        node = binder_get_node(proc, fp->binder);
        if (!node) {
                node = binder_new_node(proc, fp);
                if (!node)
                        return -ENOMEM;
        }
        if (fp->cookie != node->cookie) {
                binder_user_error("%d:%d sending u%016llx node %d, cookie mismatch %016llx != %016llx\n",
                                  proc->pid, thread->pid, (u64)fp->binder,
                                  node->debug_id, (u64)fp->cookie,
                                  (u64)node->cookie);
                ret = -EINVAL;
                goto done;
        }
        if (security_binder_transfer_binder(proc->tsk, target_proc->tsk)) {
                ret = -EPERM;
                goto done;
        }

        ret = binder_inc_ref_for_node(target_proc, node,
                        fp->hdr.type == BINDER_TYPE_BINDER,
                        &thread->todo, &rdata);
        if (ret)
                goto done;

        if (fp->hdr.type == BINDER_TYPE_BINDER)
                fp->hdr.type = BINDER_TYPE_HANDLE;
        else
                fp->hdr.type = BINDER_TYPE_WEAK_HANDLE;
        fp->binder = 0;
        fp->handle = rdata.desc;
        fp->cookie = 0;

        trace_binder_transaction_node_to_ref(t, node, &rdata);
        binder_debug(BINDER_DEBUG_TRANSACTION,
                     "        node %d u%016llx -> ref %d desc %d\n",
                     node->debug_id, (u64)node->ptr,
                     rdata.debug_id, rdata.desc);
done:
        binder_put_node(node);
        return ret;
}

static int binder_translate_handle(struct flat_binder_object *fp,
                                   struct binder_transaction *t,
                                   struct binder_thread *thread)
{
        struct binder_proc *proc = thread->proc;
        struct binder_proc *target_proc = t->to_proc;
        struct binder_node *node;
        struct binder_ref_data src_rdata;
        int ret = 0;

        node = binder_get_node_from_ref(proc, fp->handle,
                        fp->hdr.type == BINDER_TYPE_HANDLE, &src_rdata);
        if (!node) {
                binder_user_error("%d:%d got transaction with invalid handle, %d\n",
                                  proc->pid, thread->pid, fp->handle);
                return -EINVAL;
        }
        if (security_binder_transfer_binder(proc->tsk, target_proc->tsk)) {
                ret = -EPERM;
                goto done;
        }

        binder_node_lock(node);
        if (node->proc == target_proc) {
                if (fp->hdr.type == BINDER_TYPE_HANDLE)
                        fp->hdr.type = BINDER_TYPE_BINDER;
                else
                        fp->hdr.type = BINDER_TYPE_WEAK_BINDER;
                fp->binder = node->ptr;
                fp->cookie = node->cookie;
                if (node->proc)
                        binder_inner_proc_lock(node->proc);
                else
                        __acquire(&node->proc->inner_lock);
                binder_inc_node_nilocked(node,
                                         fp->hdr.type == BINDER_TYPE_BINDER,
                                         0, NULL);
                if (node->proc)
                        binder_inner_proc_unlock(node->proc);
                else
                        __release(&node->proc->inner_lock);
                trace_binder_transaction_ref_to_node(t, node, &src_rdata);
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "        ref %d desc %d -> node %d u%016llx\n",
                             src_rdata.debug_id, src_rdata.desc, node->debug_id,
                             (u64)node->ptr);
                binder_node_unlock(node);
        } else {
                struct binder_ref_data dest_rdata;

                binder_node_unlock(node);
                ret = binder_inc_ref_for_node(target_proc, node,
                                fp->hdr.type == BINDER_TYPE_HANDLE,
                                NULL, &dest_rdata);
                if (ret)
                        goto done;

                fp->binder = 0;
                fp->handle = dest_rdata.desc;
                fp->cookie = 0;
                trace_binder_transaction_ref_to_ref(t, node, &src_rdata,
                                                    &dest_rdata);
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "        ref %d desc %d -> ref %d desc %d (node %d)\n",
                             src_rdata.debug_id, src_rdata.desc,
                             dest_rdata.debug_id, dest_rdata.desc,
                             node->debug_id);
        }
done:
        binder_put_node(node);
        return ret;
}

static int binder_translate_fd(u32 fd, binder_size_t fd_offset,
                               struct binder_transaction *t,
                               struct binder_thread *thread,
                               struct binder_transaction *in_reply_to)
{
        struct binder_proc *proc = thread->proc;
        struct binder_proc *target_proc = t->to_proc;
        struct binder_txn_fd_fixup *fixup;
        struct file *file;
        int ret = 0;
        bool target_allows_fd;

        if (in_reply_to)
                target_allows_fd = !!(in_reply_to->flags & TF_ACCEPT_FDS);
        else
                target_allows_fd = t->buffer->target_node->accept_fds;
        if (!target_allows_fd) {
                binder_user_error("%d:%d got %s with fd, %d, but target does not allow fds\n",
                                  proc->pid, thread->pid,
                                  in_reply_to ? "reply" : "transaction",
                                  fd);
                ret = -EPERM;
                goto err_fd_not_accepted;
        }

        file = fget(fd);
        if (!file) {
                binder_user_error("%d:%d got transaction with invalid fd, %d\n",
                                  proc->pid, thread->pid, fd);
                ret = -EBADF;
                goto err_fget;
        }
        ret = security_binder_transfer_file(proc->tsk, target_proc->tsk, file);
        if (ret < 0) {
                ret = -EPERM;
                goto err_security;
        }

        /*
         * Add fixup record for this transaction. The allocation
         * of the fd in the target needs to be done from a
         * target thread.
         */
        fixup = kzalloc(sizeof(*fixup), GFP_KERNEL);
        if (!fixup) {
                ret = -ENOMEM;
                goto err_alloc;
        }
        fixup->file = file;
        fixup->offset = fd_offset;
        trace_binder_transaction_fd_send(t, fd, fixup->offset);
        list_add_tail(&fixup->fixup_entry, &t->fd_fixups);

        return ret;

err_alloc:
err_security:
        fput(file);
err_fget:
err_fd_not_accepted:
        return ret;
}

static int binder_translate_fd_array(struct binder_fd_array_object *fda,
                                     struct binder_buffer_object *parent,
                                     struct binder_transaction *t,
                                     struct binder_thread *thread,
                                     struct binder_transaction *in_reply_to)
{
        binder_size_t fdi, fd_buf_size;
        binder_size_t fda_offset;
        struct binder_proc *proc = thread->proc;
        struct binder_proc *target_proc = t->to_proc;

        fd_buf_size = sizeof(u32) * fda->num_fds;
        if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
                binder_user_error("%d:%d got transaction with invalid number of fds (%lld)\n",
                                  proc->pid, thread->pid, (u64)fda->num_fds);
                return -EINVAL;
        }
        if (fd_buf_size > parent->length ||
            fda->parent_offset > parent->length - fd_buf_size) {
                /* No space for all file descriptors here. */
                binder_user_error("%d:%d not enough space to store %lld fds in buffer\n",
                                  proc->pid, thread->pid, (u64)fda->num_fds);
                return -EINVAL;
        }
        /*
         * the source data for binder_buffer_object is visible
         * to user-space and the @buffer element is the user
         * pointer to the buffer_object containing the fd_array.
         * Convert the address to an offset relative to
         * the base of the transaction buffer.
         */
        fda_offset = (parent->buffer - (uintptr_t)t->buffer->user_data) +
                fda->parent_offset;
        if (!IS_ALIGNED((unsigned long)fda_offset, sizeof(u32))) {
                binder_user_error("%d:%d parent offset not aligned correctly.\n",
                                  proc->pid, thread->pid);
                return -EINVAL;
        }
        for (fdi = 0; fdi < fda->num_fds; fdi++) {
                u32 fd;
                int ret;
                binder_size_t offset = fda_offset + fdi * sizeof(fd);

                ret = binder_alloc_copy_from_buffer(&target_proc->alloc,
                                                    &fd, t->buffer,
                                                    offset, sizeof(fd));
                if (!ret)
                        ret = binder_translate_fd(fd, offset, t, thread,
                                                  in_reply_to);
                if (ret < 0)
                        return ret;
        }
        return 0;
}

static int binder_fixup_parent(struct binder_transaction *t,
                               struct binder_thread *thread,
                               struct binder_buffer_object *bp,
                               binder_size_t off_start_offset,
                               binder_size_t num_valid,
                               binder_size_t last_fixup_obj_off,
                               binder_size_t last_fixup_min_off)
{
        struct binder_buffer_object *parent;
        struct binder_buffer *b = t->buffer;
        struct binder_proc *proc = thread->proc;
        struct binder_proc *target_proc = t->to_proc;
        struct binder_object object;
        binder_size_t buffer_offset;
        binder_size_t parent_offset;

        if (!(bp->flags & BINDER_BUFFER_FLAG_HAS_PARENT))
                return 0;

        parent = binder_validate_ptr(target_proc, b, &object, bp->parent,
                                     off_start_offset, &parent_offset,
                                     num_valid);
        if (!parent) {
                binder_user_error("%d:%d got transaction with invalid parent offset or type\n",
                                  proc->pid, thread->pid);
                return -EINVAL;
        }

        if (!binder_validate_fixup(target_proc, b, off_start_offset,
                                   parent_offset, bp->parent_offset,
                                   last_fixup_obj_off,
                                   last_fixup_min_off)) {
                binder_user_error("%d:%d got transaction with out-of-order buffer fixup\n",
                                  proc->pid, thread->pid);
                return -EINVAL;
        }

        if (parent->length < sizeof(binder_uintptr_t) ||
            bp->parent_offset > parent->length - sizeof(binder_uintptr_t)) {
                /* No space for a pointer here! */
                binder_user_error("%d:%d got transaction with invalid parent offset\n",
                                  proc->pid, thread->pid);
                return -EINVAL;
        }
        buffer_offset = bp->parent_offset +
                        (uintptr_t)parent->buffer - (uintptr_t)b->user_data;
        if (binder_alloc_copy_to_buffer(&target_proc->alloc, b, buffer_offset,
                                        &bp->buffer, sizeof(bp->buffer))) {
                binder_user_error("%d:%d got transaction with invalid parent offset\n",
                                  proc->pid, thread->pid);
                return -EINVAL;
        }

        return 0;
}

/**
 * binder_proc_transaction() - sends a transaction to a process and wakes it up
 * @t:          transaction to send
 * @proc:       process to send the transaction to
 * @thread:     thread in @proc to send the transaction to (may be NULL)
 *
 * This function queues a transaction to the specified process. It will try
 * to find a thread in the target process to handle the transaction and
 * wake it up. If no thread is found, the work is queued to the proc
 * waitqueue.
 *
 * If the @thread parameter is not NULL, the transaction is always queued
 * to the waitlist of that specific thread.
 *
 * Return:      0 if the transaction was successfully queued
 *              BR_DEAD_REPLY if the target process or thread is dead
 *              BR_FROZEN_REPLY if the target process or thread is frozen
 */
static int binder_proc_transaction(struct binder_transaction *t,
                                    struct binder_proc *proc,
                                    struct binder_thread *thread)
{
        struct binder_node *node = t->buffer->target_node;
        bool oneway = !!(t->flags & TF_ONE_WAY);
        bool pending_async = false;

        BUG_ON(!node);
        binder_node_lock(node);
        if (oneway) {
                BUG_ON(thread);
                if (node->has_async_transaction)
                        pending_async = true;
                else
                        node->has_async_transaction = true;
        }

        binder_inner_proc_lock(proc);
        if (proc->is_frozen) {
                proc->sync_recv |= !oneway;
                proc->async_recv |= oneway;
        }

        if ((proc->is_frozen && !oneway) || proc->is_dead ||
                        (thread && thread->is_dead)) {
                binder_inner_proc_unlock(proc);
                binder_node_unlock(node);
                return proc->is_frozen ? BR_FROZEN_REPLY : BR_DEAD_REPLY;
        }

        if (!thread && !pending_async)
                thread = binder_select_thread_ilocked(proc);

        if (thread)
                binder_enqueue_thread_work_ilocked(thread, &t->work);
        else if (!pending_async)
                binder_enqueue_work_ilocked(&t->work, &proc->todo);
        else
                binder_enqueue_work_ilocked(&t->work, &node->async_todo);

        if (!pending_async)
                binder_wakeup_thread_ilocked(proc, thread, !oneway /* sync */);

        proc->outstanding_txns++;
        binder_inner_proc_unlock(proc);
        binder_node_unlock(node);

        return 0;
}

/**
 * binder_get_node_refs_for_txn() - Get required refs on node for txn
 * @node:         struct binder_node for which to get refs
 * @proc:         returns @node->proc if valid
 * @error:        if no @proc then returns BR_DEAD_REPLY
 *
 * User-space normally keeps the node alive when creating a transaction
 * since it has a reference to the target. The local strong ref keeps it
 * alive if the sending process dies before the target process processes
 * the transaction. If the source process is malicious or has a reference
 * counting bug, relying on the local strong ref can fail.
 *
 * Since user-space can cause the local strong ref to go away, we also take
 * a tmpref on the node to ensure it survives while we are constructing
 * the transaction. We also need a tmpref on the proc while we are
 * constructing the transaction, so we take that here as well.
 *
 * Return: The target_node with refs taken or NULL if no @node->proc is NULL.
 * Also sets @proc if valid. If the @node->proc is NULL indicating that the
 * target proc has died, @error is set to BR_DEAD_REPLY
 */
static struct binder_node *binder_get_node_refs_for_txn(
                struct binder_node *node,
                struct binder_proc **procp,
                uint32_t *error)
{
        struct binder_node *target_node = NULL;

        binder_node_inner_lock(node);
        if (node->proc) {
                target_node = node;
                binder_inc_node_nilocked(node, 1, 0, NULL);
                binder_inc_node_tmpref_ilocked(node);
                node->proc->tmp_ref++;
                *procp = node->proc;
        } else
                *error = BR_DEAD_REPLY;
        binder_node_inner_unlock(node);

        return target_node;
}

static void binder_transaction(struct binder_proc *proc,
                               struct binder_thread *thread,
                               struct binder_transaction_data *tr, int reply,
                               binder_size_t extra_buffers_size)
{
        int ret;
        struct binder_transaction *t;
        struct binder_work *w;
        struct binder_work *tcomplete;
        binder_size_t buffer_offset = 0;
        binder_size_t off_start_offset, off_end_offset;
        binder_size_t off_min;
        binder_size_t sg_buf_offset, sg_buf_end_offset;
        struct binder_proc *target_proc = NULL;
        struct binder_thread *target_thread = NULL;
        struct binder_node *target_node = NULL;
        struct binder_transaction *in_reply_to = NULL;
        struct binder_transaction_log_entry *e;
        uint32_t return_error = 0;
        uint32_t return_error_param = 0;
        uint32_t return_error_line = 0;
        binder_size_t last_fixup_obj_off = 0;
        binder_size_t last_fixup_min_off = 0;
        struct binder_context *context = proc->context;
        int t_debug_id = atomic_inc_return(&binder_last_id);
        char *secctx = NULL;
        u32 secctx_sz = 0;

        e = binder_transaction_log_add(&binder_transaction_log);
        e->debug_id = t_debug_id;
        e->call_type = reply ? 2 : !!(tr->flags & TF_ONE_WAY);
        e->from_proc = proc->pid;
        e->from_thread = thread->pid;
        e->target_handle = tr->target.handle;
        e->data_size = tr->data_size;
        e->offsets_size = tr->offsets_size;
        strscpy(e->context_name, proc->context->name, BINDERFS_MAX_NAME);

        if (reply) {
                binder_inner_proc_lock(proc);
                in_reply_to = thread->transaction_stack;
                if (in_reply_to == NULL) {
                        binder_inner_proc_unlock(proc);
                        binder_user_error("%d:%d got reply transaction with no transaction stack\n",
                                          proc->pid, thread->pid);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPROTO;
                        return_error_line = __LINE__;
                        goto err_empty_call_stack;
                }
                if (in_reply_to->to_thread != thread) {
                        spin_lock(&in_reply_to->lock);
                        binder_user_error("%d:%d got reply transaction with bad transaction stack, transaction %d has target %d:%d\n",
                                proc->pid, thread->pid, in_reply_to->debug_id,
                                in_reply_to->to_proc ?
                                in_reply_to->to_proc->pid : 0,
                                in_reply_to->to_thread ?
                                in_reply_to->to_thread->pid : 0);
                        spin_unlock(&in_reply_to->lock);
                        binder_inner_proc_unlock(proc);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPROTO;
                        return_error_line = __LINE__;
                        in_reply_to = NULL;
                        goto err_bad_call_stack;
                }
                thread->transaction_stack = in_reply_to->to_parent;
                binder_inner_proc_unlock(proc);
                binder_set_nice(in_reply_to->saved_priority);
                target_thread = binder_get_txn_from_and_acq_inner(in_reply_to);
                if (target_thread == NULL) {
                        /* annotation for sparse */
                        __release(&target_thread->proc->inner_lock);
                        return_error = BR_DEAD_REPLY;
                        return_error_line = __LINE__;
                        goto err_dead_binder;
                }
                if (target_thread->transaction_stack != in_reply_to) {
                        binder_user_error("%d:%d got reply transaction with bad target transaction stack %d, expected %d\n",
                                proc->pid, thread->pid,
                                target_thread->transaction_stack ?
                                target_thread->transaction_stack->debug_id : 0,
                                in_reply_to->debug_id);
                        binder_inner_proc_unlock(target_thread->proc);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPROTO;
                        return_error_line = __LINE__;
                        in_reply_to = NULL;
                        target_thread = NULL;
                        goto err_dead_binder;
                }
                target_proc = target_thread->proc;
                target_proc->tmp_ref++;
                binder_inner_proc_unlock(target_thread->proc);
        } else {
                if (tr->target.handle) {
                        struct binder_ref *ref;

                        /*
                         * There must already be a strong ref
                         * on this node. If so, do a strong
                         * increment on the node to ensure it
                         * stays alive until the transaction is
                         * done.
                         */
                        binder_proc_lock(proc);
                        ref = binder_get_ref_olocked(proc, tr->target.handle,
                                                     true);
                        if (ref) {
                                target_node = binder_get_node_refs_for_txn(
                                                ref->node, &target_proc,
                                                &return_error);
                        } else {
                                binder_user_error("%d:%d got transaction to invalid handle\n",
                                                  proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                        }
                        binder_proc_unlock(proc);
                } else {
                        mutex_lock(&context->context_mgr_node_lock);
                        target_node = context->binder_context_mgr_node;
                        if (target_node)
                                target_node = binder_get_node_refs_for_txn(
                                                target_node, &target_proc,
                                                &return_error);
                        else
                                return_error = BR_DEAD_REPLY;
                        mutex_unlock(&context->context_mgr_node_lock);
                        if (target_node && target_proc->pid == proc->pid) {
                                binder_user_error("%d:%d got transaction to context manager from process owning it\n",
                                                  proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EINVAL;
                                return_error_line = __LINE__;
                                goto err_invalid_target_handle;
                        }
                }
                if (!target_node) {
                        /*
                         * return_error is set above
                         */
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_dead_binder;
                }
                e->to_node = target_node->debug_id;
                if (WARN_ON(proc == target_proc)) {
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_invalid_target_handle;
                }
                if (security_binder_transaction(proc->tsk,
                                                target_proc->tsk) < 0) {
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPERM;
                        return_error_line = __LINE__;
                        goto err_invalid_target_handle;
                }
                binder_inner_proc_lock(proc);

                w = list_first_entry_or_null(&thread->todo,
                                             struct binder_work, entry);
                if (!(tr->flags & TF_ONE_WAY) && w &&
                    w->type == BINDER_WORK_TRANSACTION) {
                        /*
                         * Do not allow new outgoing transaction from a
                         * thread that has a transaction at the head of
                         * its todo list. Only need to check the head
                         * because binder_select_thread_ilocked picks a
                         * thread from proc->waiting_threads to enqueue
                         * the transaction, and nothing is queued to the
                         * todo list while the thread is on waiting_threads.
                         */
                        binder_user_error("%d:%d new transaction not allowed when there is a transaction on thread todo\n",
                                          proc->pid, thread->pid);
                        binder_inner_proc_unlock(proc);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPROTO;
                        return_error_line = __LINE__;
                        goto err_bad_todo_list;
                }

                if (!(tr->flags & TF_ONE_WAY) && thread->transaction_stack) {
                        struct binder_transaction *tmp;

                        tmp = thread->transaction_stack;
                        if (tmp->to_thread != thread) {
                                spin_lock(&tmp->lock);
                                binder_user_error("%d:%d got new transaction with bad transaction stack, transaction %d has target %d:%d\n",
                                        proc->pid, thread->pid, tmp->debug_id,
                                        tmp->to_proc ? tmp->to_proc->pid : 0,
                                        tmp->to_thread ?
                                        tmp->to_thread->pid : 0);
                                spin_unlock(&tmp->lock);
                                binder_inner_proc_unlock(proc);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EPROTO;
                                return_error_line = __LINE__;
                                goto err_bad_call_stack;
                        }
                        while (tmp) {
                                struct binder_thread *from;

                                spin_lock(&tmp->lock);
                                from = tmp->from;
                                if (from && from->proc == target_proc) {
                                        atomic_inc(&from->tmp_ref);
                                        target_thread = from;
                                        spin_unlock(&tmp->lock);
                                        break;
                                }
                                spin_unlock(&tmp->lock);
                                tmp = tmp->from_parent;
                        }
                }
                binder_inner_proc_unlock(proc);
        }
        if (target_thread)
                e->to_thread = target_thread->pid;
        e->to_proc = target_proc->pid;

        /* TODO: reuse incoming transaction for reply */
        t = kzalloc(sizeof(*t), GFP_KERNEL);
        if (t == NULL) {
                return_error = BR_FAILED_REPLY;
                return_error_param = -ENOMEM;
                return_error_line = __LINE__;
                goto err_alloc_t_failed;
        }
        INIT_LIST_HEAD(&t->fd_fixups);
        binder_stats_created(BINDER_STAT_TRANSACTION);
        spin_lock_init(&t->lock);

        tcomplete = kzalloc(sizeof(*tcomplete), GFP_KERNEL);
        if (tcomplete == NULL) {
                return_error = BR_FAILED_REPLY;
                return_error_param = -ENOMEM;
                return_error_line = __LINE__;
                goto err_alloc_tcomplete_failed;
        }
        binder_stats_created(BINDER_STAT_TRANSACTION_COMPLETE);

        t->debug_id = t_debug_id;

        if (reply)
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "%d:%d BC_REPLY %d -> %d:%d, data %016llx-%016llx size %lld-%lld-%lld\n",
                             proc->pid, thread->pid, t->debug_id,
                             target_proc->pid, target_thread->pid,
                             (u64)tr->data.ptr.buffer,
                             (u64)tr->data.ptr.offsets,
                             (u64)tr->data_size, (u64)tr->offsets_size,
                             (u64)extra_buffers_size);
        else
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "%d:%d BC_TRANSACTION %d -> %d - node %d, data %016llx-%016llx size %lld-%lld-%lld\n",
                             proc->pid, thread->pid, t->debug_id,
                             target_proc->pid, target_node->debug_id,
                             (u64)tr->data.ptr.buffer,
                             (u64)tr->data.ptr.offsets,
                             (u64)tr->data_size, (u64)tr->offsets_size,
                             (u64)extra_buffers_size);

        if (!reply && !(tr->flags & TF_ONE_WAY))
                t->from = thread;
        else
                t->from = NULL;
        t->sender_euid = task_euid(proc->tsk);
        t->to_proc = target_proc;
        t->to_thread = target_thread;
        t->code = tr->code;
        t->flags = tr->flags;
        t->priority = task_nice(current);

        if (target_node && target_node->txn_security_ctx) {
                u32 secid;
                size_t added_size;

                /*
                 * Arguably this should be the task's subjective LSM secid but
                 * we can't reliably access the subjective creds of a task
                 * other than our own so we must use the objective creds, which
                 * are safe to access.  The downside is that if a task is
                 * temporarily overriding it's creds it will not be reflected
                 * here; however, it isn't clear that binder would handle that
                 * case well anyway.
                 */
                security_task_getsecid_obj(proc->tsk, &secid);
                ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
                if (ret) {
                        return_error = BR_FAILED_REPLY;
                        return_error_param = ret;
                        return_error_line = __LINE__;
                        goto err_get_secctx_failed;
                }
                added_size = ALIGN(secctx_sz, sizeof(u64));
                extra_buffers_size += added_size;
                if (extra_buffers_size < added_size) {
                        /* integer overflow of extra_buffers_size */
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_bad_extra_size;
                }
        }

        trace_binder_transaction(reply, t, target_node);

        t->buffer = binder_alloc_new_buf(&target_proc->alloc, tr->data_size,
                tr->offsets_size, extra_buffers_size,
                !reply && (t->flags & TF_ONE_WAY), current->tgid);
        if (IS_ERR(t->buffer)) {
                /*
                 * -ESRCH indicates VMA cleared. The target is dying.
                 */
                return_error_param = PTR_ERR(t->buffer);
                return_error = return_error_param == -ESRCH ?
                        BR_DEAD_REPLY : BR_FAILED_REPLY;
                return_error_line = __LINE__;
                t->buffer = NULL;
                goto err_binder_alloc_buf_failed;
        }
        if (secctx) {
                int err;
                size_t buf_offset = ALIGN(tr->data_size, sizeof(void *)) +
                                    ALIGN(tr->offsets_size, sizeof(void *)) +
                                    ALIGN(extra_buffers_size, sizeof(void *)) -
                                    ALIGN(secctx_sz, sizeof(u64));

                t->security_ctx = (uintptr_t)t->buffer->user_data + buf_offset;
                err = binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                  t->buffer, buf_offset,
                                                  secctx, secctx_sz);
                if (err) {
                        t->security_ctx = 0;
                        WARN_ON(1);
                }
                security_release_secctx(secctx, secctx_sz);
                secctx = NULL;
        }
        t->buffer->debug_id = t->debug_id;
        t->buffer->transaction = t;
        t->buffer->target_node = target_node;
        t->buffer->clear_on_free = !!(t->flags & TF_CLEAR_BUF);
        trace_binder_transaction_alloc_buf(t->buffer);

        if (binder_alloc_copy_user_to_buffer(
                                &target_proc->alloc,
                                t->buffer, 0,
                                (const void __user *)
                                        (uintptr_t)tr->data.ptr.buffer,
                                tr->data_size)) {
                binder_user_error("%d:%d got transaction with invalid data ptr\n",
                                proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                return_error_param = -EFAULT;
                return_error_line = __LINE__;
                goto err_copy_data_failed;
        }
        if (binder_alloc_copy_user_to_buffer(
                                &target_proc->alloc,
                                t->buffer,
                                ALIGN(tr->data_size, sizeof(void *)),
                                (const void __user *)
                                        (uintptr_t)tr->data.ptr.offsets,
                                tr->offsets_size)) {
                binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
                                proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                return_error_param = -EFAULT;
                return_error_line = __LINE__;
                goto err_copy_data_failed;
        }
        if (!IS_ALIGNED(tr->offsets_size, sizeof(binder_size_t))) {
                binder_user_error("%d:%d got transaction with invalid offsets size, %lld\n",
                                proc->pid, thread->pid, (u64)tr->offsets_size);
                return_error = BR_FAILED_REPLY;
                return_error_param = -EINVAL;
                return_error_line = __LINE__;
                goto err_bad_offset;
        }
        if (!IS_ALIGNED(extra_buffers_size, sizeof(u64))) {
                binder_user_error("%d:%d got transaction with unaligned buffers size, %lld\n",
                                  proc->pid, thread->pid,
                                  (u64)extra_buffers_size);
                return_error = BR_FAILED_REPLY;
                return_error_param = -EINVAL;
                return_error_line = __LINE__;
                goto err_bad_offset;
        }
        off_start_offset = ALIGN(tr->data_size, sizeof(void *));
        buffer_offset = off_start_offset;
        off_end_offset = off_start_offset + tr->offsets_size;
        sg_buf_offset = ALIGN(off_end_offset, sizeof(void *));
        sg_buf_end_offset = sg_buf_offset + extra_buffers_size -
                ALIGN(secctx_sz, sizeof(u64));
        off_min = 0;
        for (buffer_offset = off_start_offset; buffer_offset < off_end_offset;
             buffer_offset += sizeof(binder_size_t)) {
                struct binder_object_header *hdr;
                size_t object_size;
                struct binder_object object;
                binder_size_t object_offset;

                if (binder_alloc_copy_from_buffer(&target_proc->alloc,
                                                  &object_offset,
                                                  t->buffer,
                                                  buffer_offset,
                                                  sizeof(object_offset))) {
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_bad_offset;
                }
                object_size = binder_get_object(target_proc, t->buffer,
                                                object_offset, &object);
                if (object_size == 0 || object_offset < off_min) {
                        binder_user_error("%d:%d got transaction with invalid offset (%lld, min %lld max %lld) or object.\n",
                                          proc->pid, thread->pid,
                                          (u64)object_offset,
                                          (u64)off_min,
                                          (u64)t->buffer->data_size);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_bad_offset;
                }

                hdr = &object.hdr;
                off_min = object_offset + object_size;
                switch (hdr->type) {
                case BINDER_TYPE_BINDER:
                case BINDER_TYPE_WEAK_BINDER: {
                        struct flat_binder_object *fp;

                        fp = to_flat_binder_object(hdr);
                        ret = binder_translate_binder(fp, t, thread);

                        if (ret < 0 ||
                            binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                        t->buffer,
                                                        object_offset,
                                                        fp, sizeof(*fp))) {
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                } break;
                case BINDER_TYPE_HANDLE:
                case BINDER_TYPE_WEAK_HANDLE: {
                        struct flat_binder_object *fp;

                        fp = to_flat_binder_object(hdr);
                        ret = binder_translate_handle(fp, t, thread);
                        if (ret < 0 ||
                            binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                        t->buffer,
                                                        object_offset,
                                                        fp, sizeof(*fp))) {
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                } break;

                case BINDER_TYPE_FD: {
                        struct binder_fd_object *fp = to_binder_fd_object(hdr);
                        binder_size_t fd_offset = object_offset +
                                (uintptr_t)&fp->fd - (uintptr_t)fp;
                        int ret = binder_translate_fd(fp->fd, fd_offset, t,
                                                      thread, in_reply_to);

                        fp->pad_binder = 0;
                        if (ret < 0 ||
                            binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                        t->buffer,
                                                        object_offset,
                                                        fp, sizeof(*fp))) {
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                } break;
                case BINDER_TYPE_FDA: {
                        struct binder_object ptr_object;
                        binder_size_t parent_offset;
                        struct binder_fd_array_object *fda =
                                to_binder_fd_array_object(hdr);
                        size_t num_valid = (buffer_offset - off_start_offset) /
                                                sizeof(binder_size_t);
                        struct binder_buffer_object *parent =
                                binder_validate_ptr(target_proc, t->buffer,
                                                    &ptr_object, fda->parent,
                                                    off_start_offset,
                                                    &parent_offset,
                                                    num_valid);
                        if (!parent) {
                                binder_user_error("%d:%d got transaction with invalid parent offset or type\n",
                                                  proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EINVAL;
                                return_error_line = __LINE__;
                                goto err_bad_parent;
                        }
                        if (!binder_validate_fixup(target_proc, t->buffer,
                                                   off_start_offset,
                                                   parent_offset,
                                                   fda->parent_offset,
                                                   last_fixup_obj_off,
                                                   last_fixup_min_off)) {
                                binder_user_error("%d:%d got transaction with out-of-order buffer fixup\n",
                                                  proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EINVAL;
                                return_error_line = __LINE__;
                                goto err_bad_parent;
                        }
                        ret = binder_translate_fd_array(fda, parent, t, thread,
                                                        in_reply_to);
                        if (ret < 0) {
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                        last_fixup_obj_off = parent_offset;
                        last_fixup_min_off =
                                fda->parent_offset + sizeof(u32) * fda->num_fds;
                } break;
                case BINDER_TYPE_PTR: {
                        struct binder_buffer_object *bp =
                                to_binder_buffer_object(hdr);
                        size_t buf_left = sg_buf_end_offset - sg_buf_offset;
                        size_t num_valid;

                        if (bp->length > buf_left) {
                                binder_user_error("%d:%d got transaction with too large buffer\n",
                                                  proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EINVAL;
                                return_error_line = __LINE__;
                                goto err_bad_offset;
                        }
                        if (binder_alloc_copy_user_to_buffer(
                                                &target_proc->alloc,
                                                t->buffer,
                                                sg_buf_offset,
                                                (const void __user *)
                                                        (uintptr_t)bp->buffer,
                                                bp->length)) {
                                binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
                                                  proc->pid, thread->pid);
                                return_error_param = -EFAULT;
                                return_error = BR_FAILED_REPLY;
                                return_error_line = __LINE__;
                                goto err_copy_data_failed;
                        }
                        /* Fixup buffer pointer to target proc address space */
                        bp->buffer = (uintptr_t)
                                t->buffer->user_data + sg_buf_offset;