Binder进程间通信机制的Service Manager组件响应Service组件的注册过程
在Android系统的Binder进程间通信机制中，Service Manager组件在启动之后，主线程会进入到Binder驱动程序的函数binder_thread_read中等待todo队列有新的工作项需要处理。当有Service组件通过Service Manager注册时，Binder驱动程序将类型为BINDER_WORK_TRANSACTION的工作项添加到Service Manager进程的todo队列中，Service Manger主线程被唤醒，继续执行binder_thread_read函数。
void binder_loop(struct binder_state *bs, binder_handler func)
{
int res;
//binder_write_read结构体bwr用来描述进程间通信过程中所传输的数据
//write表示输入(写入)数据，即从用户空间的进程到内核空间的Binder驱动程序
//read表示输出(读出)数据，即从内核空间的Binder驱动程序返回到用户空间的进程,是进程间通信的结果
struct binder_write_read bwr;
uint32_t readbuf[32];
//"write"是指往Binder驱动程序写入命令协议
bwr.write_size = 0;
bwr.write_consumed = 0;
bwr.write_buffer = 0;
/*Service Manager使用BC_ENTER_LOOPER协议将自己注册到Binder驱动程序中
主动成为一个Binder线程，以便Binder驱动程序将进程间通信请求分发给它处理*/
//将协议代码BC_ENTER_LOOPER写到缓冲区readbuf中
readbuf[0] = BC_ENTER_LOOPER;
//将缓冲区中的协议代码写入到Binder驱动程序中
binder_write(bs, readbuf, sizeof(uint32_t));
for (;;) {
//"read"是指从Binder驱动程序中读出进程间通信请求
bwr.read_size = sizeof(readbuf);
bwr.read_consumed = 0;
bwr.read_buffer = (uintptr_t) readbuf;
//循环使用IO控制命令BINDER_WRITE_READ来检查Binder驱动程序是否有新的进程间通信请求需要处理
res = ioctl(bs->fd, BINDER_WRITE_READ, &bwr);
if (res < 0) {
ALOGE("binder_loop: ioctl failed (%s)\n", strerror(errno));
break;
}
//处理Binder驱动程序发来的进程间通信请求
res = binder_parse(bs, 0, (uintptr_t) readbuf, bwr.read_consumed, func);
if (res == 0) {
ALOGE("binder_loop: unexpected reply?!\n");
break;
}
if (res < 0) {
ALOGE("binder_loop: io error %d %s\n", res, strerror(errno));
break;
}
}
}
static int
binder_thread_read(struct binder_proc *proc, struct binder_thread *thread,
void __user *buffer, int size, signed long *consumed, int non_block)
{
void __user *ptr = buffer + *consumed;
void __user *end = buffer + size;
int ret = 0;
int wait_for_proc_work;
if (*consumed == 0) {
if (put_user(BR_NOOP, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
}
retry:
/*只有当没有在等待其他线程完成另外的事务和没有未处理的事项的时候
才会将wait_for_proc_work置为1*/
wait_for_proc_work = thread->transaction_stack == NULL && list_empty(&thread->todo);
if (thread->return_error != BR_OK && ptr < end) {
if (thread->return_error2 != BR_OK) {
if (put_user(thread->return_error2, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
if (ptr == end)
goto done;
thread->return_error2 = BR_OK;
}
if (put_user(thread->return_error, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
thread->return_error = BR_OK;
goto done;
}
//线程处于空闲状态
thread->looper |= BINDER_LOOPER_STATE_WAITING;
if (wait_for_proc_work)
//当前线程所属进程又多了一个空闲的Binder线程
proc->ready_threads++;
mutex_unlock(&binder_lock);
if (wait_for_proc_work) {
//检查当前线程检查所属进程的todo队列中是否有未处理工作项
if (!(thread->looper & (BINDER_LOOPER_STATE_REGISTERED |
BINDER_LOOPER_STATE_ENTERED))) {
binder_user_error("binder: %d:%d ERROR: Thread waiting "
"for process work before calling BC_REGISTER_"
"LOOPER or BC_ENTER_LOOPER (state %x)\n",
proc->pid, thread->pid, thread->looper);
wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
}
//将当前线程的优先级设为所属进程的优先级
binder_set_nice(proc->default_priority);
if (non_block) {
if (!binder_has_proc_work(proc, thread))
ret = -EAGAIN;
} else
ret = wait_event_interruptible_exclusive(proc->wait, binder_has_proc_work(proc, thread));
} else {
if (non_block) {
if (!binder_has_thread_work(thread))
ret = -EAGAIN;
} else
ret = wait_event_interruptible(thread->wait, binder_has_thread_work(thread));
}
mutex_lock(&binder_lock);
if (wait_for_proc_work)
//减少当前线程所属进程空闲的Binder线程
proc->ready_threads--;
thread->looper &= ~BINDER_LOOPER_STATE_WAITING;
if (ret)
return ret;
while (1) {
//循环处理工作项
uint32_t cmd;
struct binder_transaction_data tr;
struct binder_work *w;
struct binder_transaction *t = NULL;
if (!list_empty(&thread->todo))
//先检查线程线程有无工作项处理
w = list_first_entry(&thread->todo, struct binder_work, entry);
else if (!list_empty(&proc->todo) && wait_for_proc_work)
//再检查线程所属进程有无工作项处理
//假设Binder驱动程序已经将一个类型为BINDER_WORK_TRANSACTION的工作项添加到了Service Manager进程的todo队列中，这里取出工作项保存在binder_work结构体w中
w = list_first_entry(&proc->todo, struct binder_work, entry);
else {
if (ptr - buffer == 4 && !(thread->looper & BINDER_LOOPER_STATE_NEED_RETURN)) /* no data added */
goto retry;
break;
}
if (end - ptr < sizeof(tr) + 4)
break;
switch (w->type) {
case BINDER_WORK_TRANSACTION: {
//将binder_work结构体w转换成binder_transaction结构体
t = container_of(w, struct binder_transaction, work);
} break;
case BINDER_WORK_TRANSACTION_COMPLETE: {
cmd = BR_TRANSACTION_COMPLETE;
//将一个BINDER_WORK_TRANSACTION_COMPLETE返回协议写入到用户空间提供的缓冲区中
if (put_user(cmd, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
binder_stat_br(proc, thread, cmd);
if (binder_debug_mask & BINDER_DEBUG_TRANSACTION_COMPLETE)
printk(KERN_INFO "binder: %d:%d BR_TRANSACTION_COMPLETE\n",
proc->pid, thread->pid);
list_del(&w->entry);
kfree(w);
binder_stats.obj_deleted[BINDER_STAT_TRANSACTION_COMPLETE]++;
} break;
case BINDER_WORK_NODE: {
struct binder_node *node = container_of(w, struct binder_node, work);
uint32_t cmd = BR_NOOP;
const char *cmd_name;
int strong = node->internal_strong_refs || node->local_strong_refs;
int weak = !hlist_empty(&node->refs) || node->local_weak_refs || strong;
if (weak && !node->has_weak_ref) {
cmd = BR_INCREFS;
cmd_name = "BR_INCREFS";
node->has_weak_ref = 1;
node->pending_weak_ref = 1;
node->local_weak_refs++;
} else if (strong && !node->has_strong_ref) {
cmd = BR_ACQUIRE;
cmd_name = "BR_ACQUIRE";
node->has_strong_ref = 1;
node->pending_strong_ref = 1;
node->local_strong_refs++;
} else if (!strong && node->has_strong_ref) {
cmd = BR_RELEASE;
cmd_name = "BR_RELEASE";
node->has_strong_ref = 0;
} else if (!weak && node->has_weak_ref) {
cmd = BR_DECREFS;
cmd_name = "BR_DECREFS";
node->has_weak_ref = 0;
}
if (cmd != BR_NOOP) {
if (put_user(cmd, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
if (put_user(node->ptr, (void * __user *)ptr))
return -EFAULT;
ptr += sizeof(void *);
if (put_user(node->cookie, (void * __user *)ptr))
return -EFAULT;
ptr += sizeof(void *);
binder_stat_br(proc, thread, cmd);
if (binder_debug_mask & BINDER_DEBUG_USER_REFS)
printk(KERN_INFO "binder: %d:%d %s %d u%p c%p\n",
proc->pid, thread->pid, cmd_name, node->debug_id, node->ptr, node->cookie);
} else {
list_del_init(&w->entry);
if (!weak && !strong) {
if (binder_debug_mask & BINDER_DEBUG_INTERNAL_REFS)
printk(KERN_INFO "binder: %d:%d node %d u%p c%p deleted\n",
proc->pid, thread->pid, node->debug_id, node->ptr, node->cookie);
rb_erase(&node->rb_node, &proc->nodes);
kfree(node);
binder_stats.obj_deleted[BINDER_STAT_NODE]++;
} else {
if (binder_debug_mask & BINDER_DEBUG_INTERNAL_REFS)
printk(KERN_INFO "binder: %d:%d node %d u%p c%p state unchanged\n",
proc->pid, thread->pid, node->debug_id, node->ptr, node->cookie);
}
}
} break;
case BINDER_WORK_DEAD_BINDER:
case BINDER_WORK_DEAD_BINDER_AND_CLEAR:
case BINDER_WORK_CLEAR_DEATH_NOTIFICATION: {
struct binder_ref_death *death = container_of(w, struct binder_ref_death, work);
uint32_t cmd;
if (w->type == BINDER_WORK_CLEAR_DEATH_NOTIFICATION)
cmd = BR_CLEAR_DEATH_NOTIFICATION_DONE;
else
cmd = BR_DEAD_BINDER;
if (put_user(cmd, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
if (put_user(death->cookie, (void * __user *)ptr))
return -EFAULT;
ptr += sizeof(void *);
if (binder_debug_mask & BINDER_DEBUG_DEATH_NOTIFICATION)
printk(KERN_INFO "binder: %d:%d %s %p\n",
proc->pid, thread->pid,
cmd == BR_DEAD_BINDER ?
"BR_DEAD_BINDER" :
"BR_CLEAR_DEATH_NOTIFICATION_DONE",
death->cookie);
if (w->type == BINDER_WORK_CLEAR_DEATH_NOTIFICATION) {
list_del(&w->entry);
kfree(death);
binder_stats.obj_deleted[BINDER_STAT_DEATH]++;
} else
list_move(&w->entry, &proc->delivered_death);
if (cmd == BR_DEAD_BINDER)
goto done; /* DEAD_BINDER notifications can cause transactions */
} break;
}
if (!t)
continue;
BUG_ON(t->buffer == NULL);
if (t->buffer->target_node) {
struct binder_node *target_node = t->buffer->target_node;
tr.target.ptr = target_node->ptr;
tr.cookie = target_node->cookie;
t->saved_priority = task_nice(current);
if (t->priority < target_node->min_priority &&
!(t->flags & TF_ONE_WAY))
binder_set_nice(t->priority);
else if (!(t->flags & TF_ONE_WAY) ||
t->saved_priority > target_node->min_priority)
binder_set_nice(target_node->min_priority);
cmd = BR_TRANSACTION;
} else {
tr.target.ptr = NULL;
tr.cookie = NULL;
cmd = BR_REPLY;
}
tr.code = t->code;
tr.flags = t->flags;
tr.sender_euid = t->sender_euid;
if (t->from) {
struct task_struct *sender = t->from->proc->tsk;
tr.sender_pid = task_tgid_nr_ns(sender, current->nsproxy->pid_ns);
} else {
tr.sender_pid = 0;
}
tr.data_size = t->buffer->data_size;
tr.offsets_size = t->buffer->offsets_size;
tr.data.ptr.buffer = (void *)t->buffer->data + proc->user_buffer_offset;
tr.data.ptr.offsets = tr.data.ptr.buffer + ALIGN(t->buffer->data_size, sizeof(void *));
if (put_user(cmd, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
if (copy_to_user(ptr, &tr, sizeof(tr)))
return -EFAULT;
ptr += sizeof(tr);
binder_stat_br(proc, thread, cmd);
if (binder_debug_mask & BINDER_DEBUG_TRANSACTION)
printk(KERN_INFO "binder: %d:%d %s %d %d:%d, cmd %d"
"size %zd-%zd ptr %p-%p\n",
proc->pid, thread->pid,
(cmd == BR_TRANSACTION) ? "BR_TRANSACTION" : "BR_REPLY",
t->debug_id, t->from ? t->from->proc->pid : 0,
t->from ? t->from->pid : 0, cmd,
t->buffer->data_size, t->buffer->offsets_size,
tr.data.ptr.buffer, tr.data.ptr.offsets);
list_del(&t->work.entry);
t->buffer->allow_user_free = 1;
if (cmd == BR_TRANSACTION && !(t->flags & TF_ONE_WAY)) {
t->to_parent = thread->transaction_stack;
t->to_thread = thread;
thread->transaction_stack = t;
} else {
t->buffer->transaction = NULL;
kfree(t);
binder_stats.obj_deleted[BINDER_STAT_TRANSACTION]++;
}
break;
}
done:
*consumed = ptr - buffer;
if (proc->requested_threads + proc->ready_threads == 0 &&
proc->requested_threads_started < proc->max_threads &&
(thread->looper & (BINDER_LOOPER_STATE_REGISTERED |
BINDER_LOOPER_STATE_ENTERED)) /* the user-space code fails to */
/*spawn a new thread if we leave this out */) {
//请求当前线程所属进程增加一个新的Binder线程来处理进程间通信请求
proc->requested_threads++;
if (binder_debug_mask & BINDER_DEBUG_THREADS)
printk(KERN_INFO "binder: %d:%d BR_SPAWN_LOOPER\n",
proc->pid, thread->pid);
if (put_user(BR_SPAWN_LOOPER, (uint32_t __user *)buffer))
return -EFAULT;
}
return 0;
}
int binder_parse(struct binder_state *bs, struct binder_io *bio,
uintptr_t ptr, size_t size, binder_handler func)
{
int r = 1;
uintptr_t end = ptr + (uintptr_t) size;
while (ptr < end) {
//读出协议命令
uint32_t cmd = *(uint32_t *) ptr;
ptr += sizeof(uint32_t);
#if TRACE
fprintf(stderr,"%s:\n", cmd_name(cmd));
#endif
switch(cmd) {
case BR_NOOP:
break;
case BR_TRANSACTION_COMPLETE:
break;
case BR_INCREFS:
case BR_ACQUIRE:
case BR_RELEASE:
case BR_DECREFS:
#if TRACE
fprintf(stderr," %p, %p\n", (void *)ptr, (void *)(ptr + sizeof(void *)));
#endif
ptr += sizeof(struct binder_ptr_cookie);
break;
case BR_TRANSACTION: {
//将返回的命令协议读取到一个binder_txn结构体
struct binder_transaction_data *txn = (struct binder_transaction_data *) ptr;
if ((end - ptr) < sizeof(*txn)) {
ALOGE("parse: txn too small!\n");
return -1;
}
binder_dump_txn(txn);
if (func) {
unsigned rdata[256/4];
struct binder_io msg;
struct binder_io reply;
int res;
//初始化binder_io结构体reply
bio_init(&reply, rdata, sizeof(rdata), 4);
//初始化binder_io结构体msg
bio_init_from_txn(&msg, txn);
//func指向Service Manager进程中的函数svcmgr_handle,处理保存在binder_io结构体msg中的BR_TRANSACTION协议,并将结果保存在binder_io及结构体reply中
res = func(bs, txn, &msg, &reply);
//将通信结果binder_io结构体reply返回给Binder驱动程序
binder_send_reply(bs, &reply, txn->data.ptr.buffer, res);
}
ptr += sizeof(*txn);
break;
}
case BR_REPLY: {
struct binder_transaction_data *txn = (struct binder_transaction_data *) ptr;
if ((end - ptr) < sizeof(*txn)) {
ALOGE("parse: reply too small!\n");
return -1;
}
binder_dump_txn(txn);
if (bio) {
bio_init_from_txn(bio, txn);
bio = 0;
} else {
/* todo FREE BUFFER */
}
ptr += sizeof(*txn);
r = 0;
break;
}
case BR_DEAD_BINDER: {
struct binder_death *death = (struct binder_death *)(uintptr_t) *(binder_uintptr_t *)ptr;
ptr += sizeof(binder_uintptr_t);
death->func(bs, death->ptr);
break;
}
case BR_FAILED_REPLY:
r = -1;
break;
case BR_DEAD_REPLY:
r = -1;
break;
default:
ALOGE("parse: OOPS %d\n", cmd);
return -1;
}
}
return r;
}
void bio_init(struct binder_io *bio, void *data,
size_t maxdata, size_t maxoffs)
{
size_t n = maxoffs * sizeof(size_t);
if (n > maxdata) {
bio->flags = BIO_F_OVERFLOW;
bio->data_avail = 0;
bio->offs_avail = 0;
return;
}
bio->data = bio->data0 = (char *) data + n;
bio->offs = bio->offs0 = data;
bio->data_avail = maxdata - n;
bio->offs_avail = maxoffs;
bio->flags = 0;
}
void bio_init_from_txn(struct binder_io *bio, struct binder_transaction_data *txn)
{
bio->data = bio->data0 = (char *)(intptr_t)txn->data.ptr.buffer;
bio->offs = bio->offs0 = (binder_size_t *)(intptr_t)txn->data.ptr.offsets;
bio->data_avail = txn->data_size;
bio->offs_avail = txn->offsets_size / sizeof(size_t);
bio->flags = BIO_F_SHARED;
}
int svcmgr_handler(struct binder_state *bs,
struct binder_transaction_data *txn,
struct binder_io *msg,
struct binder_io *reply)
{
struct svcinfo *si;
uint16_t *s;
size_t len;
uint32_t handle;
uint32_t strict_policy;
int allow_isolated;
//ALOGI("target=%x code=%d pid=%d uid=%d\n",
// txn->target.handle, txn->code, txn->sender_pid, txn->sender_euid);
if (txn->target.handle != svcmgr_handle)
return -1;
if (txn->code == PING_TRANSACTION)
return 0;
// Equivalent to Parcel::enforceInterface(), reading the RPC
// header with the strict mode policy mask and the interface name.
// Note that we ignore the strict_policy and don't propagate it
// further (since we do no outbound RPCs anyway).
strict_policy = bio_get_uint32(msg);
s = bio_get_string16(msg, &len);
if (s == NULL) {
return -1;
}
if ((len != (sizeof(svcmgr_id) / 2)) ||
memcmp(svcmgr_id, s, sizeof(svcmgr_id))) {
fprintf(stderr,"invalid id %s\n", str8(s, len));
return -1;
}
if (sehandle && selinux_status_updated() > 0) {
struct selabel_handle *tmp_sehandle = selinux_android_service_context_handle();
if (tmp_sehandle) {
selabel_close(sehandle);
sehandle = tmp_sehandle;
}
}
switch(txn->code) {
case SVC_MGR_GET_SERVICE:
case SVC_MGR_CHECK_SERVICE:
s = bio_get_string16(msg, &len);
if (s == NULL) {
return -1;
}
handle = do_find_service(bs, s, len, txn->sender_euid, txn->sender_pid);
if (!handle)
break;
bio_put_ref(reply, handle);
return 0;
case SVC_MGR_ADD_SERVICE:
//取出Service组件的名称
s = bio_get_string16(msg, &len);
if (s == NULL) {
return -1;
}
//调用函数bio_get_ref从binder_io结构体msg的数据缓冲区中获得一个Binder引用对象的句柄值，这个Binder引用对象是在Binder驱动程序中创建的，引用了即将要注册的Service组件
handle = bio_get_ref(msg);
allow_isolated = bio_get_uint32(msg) ? 1 : 0;
if (do_add_service(bs, s, len, handle, txn->sender_euid,
allow_isolated, txn->sender_pid))
return -1;
break;
case SVC_MGR_LIST_SERVICES: {
uint32_t n = bio_get_uint32(msg);
if (!svc_can_list(txn->sender_pid)) {
ALOGE("list_service() uid=%d - PERMISSION DENIED\n",
txn->sender_euid);
return -1;
}
si = svclist;
while ((n-- > 0) && si)
si = si->next;
if (si) {
bio_put_string16(reply, si->name);
return 0;
}
return -1;
}
default:
ALOGE("unknown code %d\n", txn->code);
return -1;
}
//成功代码0写入到binder_io结构体reply中，以便返回给请求注册Service组件的进程
bio_put_uint32(reply, 0);
return 0;
}
uint32_t do_find_service(struct binder_state *bs, const uint16_t *s, size_t len, uid_t uid, pid_t spid)
{
struct svcinfo *si;
if (!svc_can_find(s, len, spid)) {
ALOGE("find_service('%s') uid=%d - PERMISSION DENIED\n",
str8(s, len), uid);
return 0;
}
si = find_svc(s, len);
//ALOGI("check_service('%s') handle = %x\n", str8(s, len), si ? si->handle : 0);
if (si && si->handle) {
if (!si->allow_isolated) {
// If this service doesn't allow access from isolated processes,
// then check the uid to see if it is isolated.
uid_t appid = uid % AID_USER;
if (appid >= AID_ISOLATED_START && appid <= AID_ISOLATED_END) {
return 0;
}
}
return si->handle;
} else {
return 0;
}
}
static int svc_can_find(const uint16_t *name, size_t name_len, pid_t spid)
{
const char *perm = "find";
return check_mac_perms_from_lookup(spid, perm, str8(name, name_len)) ? 1 : 0;
}
struct svcinfo *find_svc(const uint16_t *s16, size_t len)
{
struct svcinfo *si;
for (si = svclist; si; si = si->next) {
if ((len == si->len) &&
!memcmp(s16, si->name, len * sizeof(uint16_t))) {
return si;
}
}
return NULL;
}
void binder_send_reply(struct binder_state *bs,
struct binder_io *reply,
binder_uintptr_t buffer_to_free,
int status)
{
struct {
uint32_t cmd_free;
binder_uintptr_t buffer;
uint32_t cmd_reply;
struct binder_transaction_data txn;
} __attribute__((packed)) data;
data.cmd_free = BC_FREE_BUFFER;
data.buffer = buffer_to_free;
data.cmd_reply = BC_REPLY;
data.txn.target.ptr = 0;
data.txn.cookie = 0;
data.txn.code = 0;
if (status) {
data.txn.flags = TF_STATUS_CODE;
data.txn.data_size = sizeof(int);
data.txn.offsets_size = 0;
data.txn.data.ptr.buffer = (uintptr_t)&status;
data.txn.data.ptr.offsets = 0;
} else {
data.txn.flags = 0;
data.txn.data_size = reply->data - reply->data0;
data.txn.offsets_size = ((char*) reply->offs) - ((char*) reply->offs0);
data.txn.data.ptr.buffer = (uintptr_t)reply->data0;
data.txn.data.ptr.offsets = (uintptr_t)reply->offs0;
}
binder_write(bs, &data, sizeof(data));
}
int binder_write(struct binder_state *bs, void *data, size_t len)
{
struct binder_write_read bwr;
int res;
bwr.write_size = len;
bwr.write_consumed = 0;
//将参数data所指向的一块缓冲区作为binder_write_read结构体bwr的输入缓冲区(写入)
bwr.write_buffer = (uintptr_t) data;
//将binder_write_read结构体bwr输出缓冲区(读出)置为空，使当前线程将自己注册到Binder驱动程序之后立刻返回到用户空间，不会在Binder驱动程序中等待Client进程的通信请求
bwr.read_size = 0;
bwr.read_consumed = 0;
bwr.read_buffer = 0;
//调用Binder驱动程序的binder_ioctl将当前线程注册到Binder驱动程序中
res = ioctl(bs->fd, BINDER_WRITE_READ, &bwr);
if (res < 0) {
fprintf(stderr,"binder_write: ioctl failed (%s)\n",
strerror(errno));
}
return res;
}
int
binder_thread_write(struct binder_proc *proc, struct binder_thread *thread,
void __user *buffer, int size, signed long *consumed)
{
uint32_t cmd;
void __user *ptr = buffer + *consumed;
void __user *end = buffer + size;
while (ptr < end && thread->return_error == BR_OK) {
if (get_user(cmd, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
if (_IOC_NR(cmd) < ARRAY_SIZE(binder_stats.bc)) {
binder_stats.bc[_IOC_NR(cmd)]++;
proc->stats.bc[_IOC_NR(cmd)]++;
thread->stats.bc[_IOC_NR(cmd)]++;
}
switch (cmd) {
case BC_INCREFS:
case BC_ACQUIRE:
case BC_RELEASE:
case BC_DECREFS: {
uint32_t target;
struct binder_ref *ref;
const char *debug_string;
if (get_user(target, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
if (target == 0 && binder_context_mgr_node &&
(cmd == BC_INCREFS || cmd == BC_ACQUIRE)) {
ref = binder_get_ref_for_node(proc,
binder_context_mgr_node);
if (ref->desc != target) {
binder_user_error("binder: %d:"
"%d tried to acquire "
"reference to desc 0, "
"got %d instead\n",
proc->pid, thread->pid,
ref->desc);
}
} else
ref = binder_get_ref(proc, target);
if (ref == NULL) {
binder_user_error("binder: %d:%d refcou"
"nt change on invalid ref %d\n",
proc->pid, thread->pid, target);
break;
}
switch (cmd) {
case BC_INCREFS:
debug_string = "IncRefs";
binder_inc_ref(ref, 0, NULL);
break;
case BC_ACQUIRE:
debug_string = "Acquire";
binder_inc_ref(ref, 1, NULL);
break;
case BC_RELEASE:
debug_string = "Release";
binder_dec_ref(ref, 1);
break;
case BC_DECREFS:
default:
debug_string = "DecRefs";
binder_dec_ref(ref, 0);
break;
}
if (binder_debug_mask & BINDER_DEBUG_USER_REFS)
printk(KERN_INFO "binder: %d:%d %s ref %d desc %d s %d w %d for node %d\n",
proc->pid, thread->pid, debug_string, ref->debug_id, ref->desc, ref->strong, ref->weak, ref->node->debug_id);
break;
}
case BC_INCREFS_DONE:
case BC_ACQUIRE_DONE: {
void __user *node_ptr;
void *cookie;
struct binder_node *node;
if (get_user(node_ptr, (void * __user *)ptr))
return -EFAULT;
ptr += sizeof(void *);
if (get_user(cookie, (void * __user *)ptr))
return -EFAULT;
ptr += sizeof(void *);
node = binder_get_node(proc, node_ptr);
if (node == NULL) {
binder_user_error("binder: %d:%d "
"%s u%p no match\n",
proc->pid, thread->pid,
cmd == BC_INCREFS_DONE ?
"BC_INCREFS_DONE" :
"BC_ACQUIRE_DONE",
node_ptr);
break;
}
if (cookie != node->cookie) {
binder_user_error("binder: %d:%d %s u%p node %d"
" cookie mismatch %p != %p\n",
proc->pid, thread->pid,
cmd == BC_INCREFS_DONE ?
"BC_INCREFS_DONE" : "BC_ACQUIRE_DONE",
node_ptr, node->debug_id,
cookie, node->cookie);
break;
}
if (cmd == BC_ACQUIRE_DONE) {
if (node->pending_strong_ref == 0) {
binder_user_error("binder: %d:%d "
"BC_ACQUIRE_DONE node %d has "
"no pending acquire request\n",
proc->pid, thread->pid,
node->debug_id);
break;
}
node->pending_strong_ref = 0;
} else {
if (node->pending_weak_ref == 0) {
binder_user_error("binder: %d:%d "
"BC_INCREFS_DONE node %d has "
"no pending increfs request\n",
proc->pid, thread->pid,
node->debug_id);
break;
}
node->pending_weak_ref = 0;
}
binder_dec_node(node, cmd == BC_ACQUIRE_DONE, 0);
if (binder_debug_mask & BINDER_DEBUG_USER_REFS)
printk(KERN_INFO "binder: %d:%d %s node %d ls %d lw %d\n",
proc->pid, thread->pid, cmd == BC_INCREFS_DONE ? "BC_INCREFS_DONE" : "BC_ACQUIRE_DONE", node->debug_id, node->local_strong_refs, node->local_weak_refs);
break;
}
case BC_ATTEMPT_ACQUIRE:
printk(KERN_ERR "binder: BC_ATTEMPT_ACQUIRE not supported\n");
return -EINVAL;
case BC_ACQUIRE_RESULT:
printk(KERN_ERR "binder: BC_ACQUIRE_RESULT not supported\n");
return -EINVAL;
case BC_FREE_BUFFER: {
void __user *data_ptr;
struct binder_buffer *buffer;
if (get_user(data_ptr, (void * __user *)ptr))
return -EFAULT;
ptr += sizeof(void *);
buffer = binder_buffer_lookup(proc, data_ptr);
if (buffer == NULL) {
binder_user_error("binder: %d:%d "
"BC_FREE_BUFFER u%p no match\n",
proc->pid, thread->pid, data_ptr);
break;
}
if (!buffer->allow_user_free) {
binder_user_error("binder: %d:%d "
"BC_FREE_BUFFER u%p matched "
"unreturned buffer\n",
proc->pid, thread->pid, data_ptr);
break;
}
if (binder_debug_mask & BINDER_DEBUG_FREE_BUFFER)
printk(KERN_INFO "binder: %d:%d BC_FREE_BUFFER u%p found buffer %d for %s transaction\n",
proc->pid, thread->pid, data_ptr, buffer->debug_id,
buffer->transaction ? "active" : "finished");
if (buffer->transaction) {
buffer->transaction->buffer = NULL;
buffer->transaction = NULL;
}
if (buffer->async_transaction && buffer->target_node) {
BUG_ON(!buffer->target_node->has_async_transaction);
if (list_empty(&buffer->target_node->async_todo))
buffer->target_node->has_async_transaction = 0;
else
list_move_tail(buffer->target_node->async_todo.next, &thread->todo);
}
binder_transaction_buffer_release(proc, buffer, NULL);
binder_free_buf(proc, buffer);
break;
}
case BC_TRANSACTION:
case BC_REPLY: {
struct binder_transaction_data tr;
if (copy_from_user(&tr, ptr, sizeof(tr)))
return -EFAULT;
ptr += sizeof(tr);
binder_transaction(proc, thread, &tr, cmd == BC_REPLY);
break;
}
case BC_REGISTER_LOOPER:
if (binder_debug_mask & BINDER_DEBUG_THREADS)
printk(KERN_INFO "binder: %d:%d BC_REGISTER_LOOPER\n",
proc->pid, thread->pid);
if (thread->looper & BINDER_LOOPER_STATE_ENTERED) {
thread->looper |= BINDER_LOOPER_STATE_INVALID;
binder_user_error("binder: %d:%d ERROR:"
" BC_REGISTER_LOOPER called "
"after BC_ENTER_LOOPER\n",
proc->pid, thread->pid);
} else if (proc->requested_threads == 0) {
thread->looper |= BINDER_LOOPER_STATE_INVALID;
binder_user_error("binder: %d:%d ERROR:"
" BC_REGISTER_LOOPER called "
"without request\n",
proc->pid, thread->pid);
} else {
proc->requested_threads--;
proc->requested_threads_started++;
}
thread->looper |= BINDER_LOOPER_STATE_REGISTERED;
break;
case BC_ENTER_LOOPER:
if (binder_debug_mask & BINDER_DEBUG_THREADS)
printk(KERN_INFO "binder: %d:%d BC_ENTER_LOOPER\n",
proc->pid, thread->pid);
if (thread->looper & BINDER_LOOPER_STATE_REGISTERED) {
thread->looper |= BINDER_LOOPER_STATE_INVALID;
binder_user_error("binder: %d:%d ERROR:"
" BC_ENTER_LOOPER called after "
"BC_REGISTER_LOOPER\n",
proc->pid, thread->pid);
}
//将目标线程thread的姿态置为BINDER_LOOPER_STATE_ENTERED表明该线程是Binder线程可以处理进程间通信请求
thread->looper |= BINDER_LOOPER_STATE_ENTERED;
break;
case BC_EXIT_LOOPER:
if (binder_debug_mask & BINDER_DEBUG_THREADS)
printk(KERN_INFO "binder: %d:%d BC_EXIT_LOOPER\n",
proc->pid, thread->pid);
thread->looper |= BINDER_LOOPER_STATE_EXITED;
break;
case BC_REQUEST_DEATH_NOTIFICATION:
case BC_CLEAR_DEATH_NOTIFICATION: {
uint32_t target;
void __user *cookie;
struct binder_ref *ref;
struct binder_ref_death *death;
if (get_user(target, (uint32_t __user *)ptr))
return -EFAULT;
ptr += sizeof(uint32_t);
if (get_user(cookie, (void __user * __user *)ptr))
return -EFAULT;
ptr += sizeof(void *);
ref = binder_get_ref(proc, target);
if (ref == NULL) {
binder_user_error("binder: %d:%d %s "
"invalid ref %d\n",
proc->pid, thread->pid,
cmd == BC_REQUEST_DEATH_NOTIFICATION ?
"BC_REQUEST_DEATH_NOTIFICATION" :
"BC_CLEAR_DEATH_NOTIFICATION",
target);
break;
}
if (binder_debug_mask & BINDER_DEBUG_DEATH_NOTIFICATION)
printk(KERN_INFO "binder: %d:%d %s %p ref %d desc %d s %d w %d for node %d\n",
proc->pid, thread->pid,
cmd == BC_REQUEST_DEATH_NOTIFICATION ?
"BC_REQUEST_DEATH_NOTIFICATION" :
"BC_CLEAR_DEATH_NOTIFICATION",
cookie, ref->debug_id, ref->desc,
ref->strong, ref->weak, ref->node->debug_id);
if (cmd == BC_REQUEST_DEATH_NOTIFICATION) {
if (ref->death) {
binder_user_error("binder: %d:%"
"d BC_REQUEST_DEATH_NOTI"
"FICATION death notific"
"ation already set\n",
proc->pid, thread->pid);
break;
}
death = kzalloc(sizeof(*death), GFP_KERNEL);
if (death == NULL) {
thread->return_error = BR_ERROR;
if (binder_debug_mask & BINDER_DEBUG_FAILED_TRANSACTION)
printk(KERN_INFO "binder: %d:%d "
"BC_REQUEST_DEATH_NOTIFICATION failed\n",
proc->pid, thread->pid);
break;
}
binder_stats.obj_created[BINDER_STAT_DEATH]++;
INIT_LIST_HEAD(&death->work.entry);
death->cookie = cookie;
ref->death = death;
if (ref->node->proc == NULL) {
ref->death->work.type = BINDER_WORK_DEAD_BINDER;
if (thread->looper & (BINDER_LOOPER_STATE_REGISTERED | BINDER_LOOPER_STATE_ENTERED)) {
list_add_tail(&ref->death->work.entry, &thread->todo);
} else {
list_add_tail(&ref->death->work.entry, &proc->todo);
wake_up_interruptible(&proc->wait);
}
}
} else {
if (ref->death == NULL) {
binder_user_error("binder: %d:%"
"d BC_CLEAR_DEATH_NOTIFI"
"CATION death notificat"
"ion not active\n",
proc->pid, thread->pid);
break;
}
death = ref->death;
if (death->cookie != cookie) {
binder_user_error("binder: %d:%"
"d BC_CLEAR_DEATH_NOTIFI"
"CATION death notificat"
"ion cookie mismatch "
"%p != %p\n",
proc->pid, thread->pid,
death->cookie, cookie);
break;
}
ref->death = NULL;
if (list_empty(&death->work.entry)) {
death->work.type = BINDER_WORK_CLEAR_DEATH_NOTIFICATION;
if (thread->looper & (BINDER_LOOPER_STATE_REGISTERED | BINDER_LOOPER_STATE_ENTERED)) {
list_add_tail(&death->work.entry, &thread->todo);
} else {
list_add_tail(&death->work.entry, &proc->todo);
wake_up_interruptible(&proc->wait);
}
} else {
BUG_ON(death->work.type != BINDER_WORK_DEAD_BINDER);
death->work.type = BINDER_WORK_DEAD_BINDER_AND_CLEAR;
}
}
} break;
case BC_DEAD_BINDER_DONE: {
struct binder_work *w;
void __user *cookie;
struct binder_ref_death *death = NULL;
if (get_user(cookie, (void __user * __user *)ptr))
return -EFAULT;
ptr += sizeof(void *);
list_for_each_entry(w, &proc->delivered_death, entry) {
struct binder_ref_death *tmp_death = container_of(w, struct binder_ref_death, work);
if (tmp_death->cookie == cookie) {
death = tmp_death;
break;
}
}
if (binder_debug_mask & BINDER_DEBUG_DEAD_BINDER)
printk(KERN_INFO "binder: %d:%d BC_DEAD_BINDER_DONE %p found %p\n",
proc->pid, thread->pid, cookie, death);
if (death == NULL) {
binder_user_error("binder: %d:%d BC_DEAD"
"_BINDER_DONE %p not found\n",
proc->pid, thread->pid, cookie);
break;
}
list_del_init(&death->work.entry);
if (death->work.type == BINDER_WORK_DEAD_BINDER_AND_CLEAR) {
death->work.type = BINDER_WORK_CLEAR_DEATH_NOTIFICATION;
if (thread->looper & (BINDER_LOOPER_STATE_REGISTERED | BINDER_LOOPER_STATE_ENTERED)) {
list_add_tail(&death->work.entry, &thread->todo);
} else {
list_add_tail(&death->work.entry, &proc->todo);
wake_up_interruptible(&proc->wait);
}
}
} break;
default:
printk(KERN_ERR "binder: %d:%d unknown command %d\n", proc->pid, thread->pid, cmd);
return -EINVAL;
}
*consumed = ptr - buffer;
}
return 0;
}
static void
binder_transaction(struct binder_proc *proc, struct binder_thread *thread,
struct binder_transaction_data *tr, int reply)
{
struct binder_transaction *t;
struct binder_work *tcomplete;
size_t *offp, *off_end;
struct binder_proc *target_proc;
struct binder_thread *target_thread = NULL;
struct binder_node *target_node = NULL;
struct list_head *target_list;
wait_queue_head_t *target_wait;
struct binder_transaction *in_reply_to = NULL;
struct binder_transaction_log_entry *e;
uint32_t return_error;
e = binder_transaction_log_add(&binder_transaction_log);
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;
if (reply) {
//处理BC_REPLY命令协议
in_reply_to = thread->transaction_stack;
if (in_reply_to == NULL) {
binder_user_error("binder: %d:%d got reply transaction "
"with no transaction stack\n",
proc->pid, thread->pid);
return_error = BR_FAILED_REPLY;
goto err_empty_call_stack;
}
binder_set_nice(in_reply_to->saved_priority);
if (in_reply_to->to_thread != thread) {
binder_user_error("binder: %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);
return_error = BR_FAILED_REPLY;
in_reply_to = NULL;
goto err_bad_call_stack;
}
thread->transaction_stack = in_reply_to->to_parent;
target_thread = in_reply_to->from;
if (target_thread == NULL) {
return_error = BR_DEAD_REPLY;
goto err_dead_binder;
}
if (target_thread->transaction_stack != in_reply_to) {
binder_user_error("binder: %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);
return_error = BR_FAILED_REPLY;
in_reply_to = NULL;
target_thread = NULL;
goto err_dead_binder;
}
target_proc = target_thread->proc;
} else {
//处理BC_TRANSACTION命令协议
if (tr->target.handle) {
struct binder_ref *ref;
ref = binder_get_ref(proc, tr->target.handle);
if (ref == NULL) {
binder_user_error("binder: %d:%d got "
"transaction to invalid handle\n",
proc->pid, thread->pid);
return_error = BR_FAILED_REPLY;
goto err_invalid_target_handle;
}
target_node = ref->node;
} else {
//因为程序Main_mediaserver给驱动程序发送BC_TRANSACTION命令协议的目的是要将Service组件MediaPlayerService注册到Service Manager?
//所以在binder_transaction_data结构体tr中，目标Binder对象是一个Binder引用对象，句柄值为0
//所以下面这句语句将目标Binder实体对象target_node指向了一个引用了Service Manager的Binder实体对象binder_context_mgr_node
//binder_context_mgr_node是在Service Manager启动的时候创建的
target_node = binder_context_mgr_node;
if (target_node == NULL) {
return_error = BR_DEAD_REPLY;
goto err_no_context_mgr_node;
}
}
e->to_node = target_node->debug_id;
//找到目标进程
target_proc = target_node->proc;
if (target_proc == NULL) {
return_error = BR_DEAD_REPLY;
goto err_dead_binder;
}
if (!(tr->flags & TF_ONE_WAY) && thread->transaction_stack) {
struct binder_transaction *tmp;
tmp = thread->transaction_stack;
if (tmp->to_thread != thread) {
binder_user_error("binder: %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);
return_error = BR_FAILED_REPLY;
goto err_bad_call_stack;
}
while (tmp) {
if (tmp->from && tmp->from->proc == target_proc)
//找到目标线程
target_thread = tmp->from;
tmp = tmp->from_parent;
}
}
}
if (target_thread) {
e->to_thread = target_thread->pid;
target_list = &target_thread->todo;
target_wait = &target_thread->wait;
} else {
target_list = &target_proc->todo;
target_wait = &target_proc->wait;
}
e->to_proc = target_proc->pid;
/* TODO: reuse incoming transaction for reply */
//分配一个binder_transaction结构体t
t = kzalloc(sizeof(*t), GFP_KERNEL);
if (t == NULL) {
return_error = BR_FAILED_REPLY;
goto err_alloc_t_failed;
}
binder_stats.obj_created[BINDER_STAT_TRANSACTION]++;
//分配一个binder_work结构体tcomplete
tcomplete = kzalloc(sizeof(*tcomplete), GFP_KERNEL);
if (tcomplete == NULL) {
return_error = BR_FAILED_REPLY;
goto err_alloc_tcomplete_failed;
}
binder_stats.obj_created[BINDER_STAT_TRANSACTION_COMPLETE]++;
t->debug_id = ++binder_last_id;
e->debug_id = t->debug_id;
if (binder_debug_mask & BINDER_DEBUG_TRANSACTION) {
if (reply)
printk(KERN_INFO "binder: %d:%d BC_REPLY %d -> %d:%d, "
"data %p-%p size %zd-%zd\n",
proc->pid, thread->pid, t->debug_id,
target_proc->pid, target_thread->pid,
tr->data.ptr.buffer, tr->data.ptr.offsets,
tr->data_size, tr->offsets_size);
else
printk(KERN_INFO "binder: %d:%d BC_TRANSACTION %d -> "
"%d - node %d, data %p-%p size %zd-%zd\n",
proc->pid, thread->pid, t->debug_id,
target_proc->pid, target_node->debug_id,
tr->data.ptr.buffer, tr->data.ptr.offsets,
tr->data_size, tr->offsets_size);
}
if (!reply && !(tr->flags & TF_ONE_WAY))
t->from = thread;
else
t->from = NULL;
t->sender_euid = proc->tsk->cred->euid;
t->to_proc = target_proc;
t->to_thread = target_thread;
t->code = tr->code;
t->flags = tr->flags;
t->priority = task_nice(current);
t->buffer = binder_alloc_buf(target_proc, tr->data_size,
tr->offsets_size, !reply && (t->flags & TF_ONE_WAY));
if (t->buffer == NULL) {
return_error = BR_FAILED_REPLY;
goto err_binder_alloc_buf_failed;
}
t->buffer->allow_user_free = 0;
t->buffer->debug_id = t->debug_id;
t->buffer->transaction = t;
t->buffer->target_node = target_node;
if (target_node)
binder_inc_node(target_node, 1, 0, NULL);
offp = (size_t *)(t->buffer->data + ALIGN(tr->data_size, sizeof(void *)));
if (copy_from_user(t->buffer->data, tr->data.ptr.buffer, tr->data_size)) {
binder_user_error("binder: %d:%d got transaction with invalid "
"data ptr\n", proc->pid, thread->pid);
return_error = BR_FAILED_REPLY;
goto err_copy_data_failed;
}
if (copy_from_user(offp, tr->data.ptr.offsets, tr->offsets_size)) {
binder_user_error("binder: %d:%d got transaction with invalid "
"offsets ptr\n", proc->pid, thread->pid);
return_error = BR_FAILED_REPLY;
goto err_copy_data_failed;
}
if (!IS_ALIGNED(tr->offsets_size, sizeof(size_t))) {
binder_user_error("binder: %d:%d got transaction with "
"invalid offsets size, %zd\n",
proc->pid, thread->pid, tr->offsets_size);
return_error = BR_FAILED_REPLY;
goto err_bad_offset;
}
off_end = (void *)offp + tr->offsets_size;
for (; offp < off_end; offp++) {
struct flat_binder_object *fp;
if (*offp > t->buffer->data_size - sizeof(*fp) ||
t->buffer->data_size < sizeof(*fp) ||
!IS_ALIGNED(*offp, sizeof(void *))) {
binder_user_error("binder: %d:%d got transaction with "
"invalid offset, %zd\n",
proc->pid, thread->pid, *offp);
return_error = BR_FAILED_REPLY;
goto err_bad_offset;
}
fp = (struct flat_binder_object *)(t->buffer->data + *offp);
switch (fp->type) {
case BINDER_TYPE_BINDER:
case BINDER_TYPE_WEAK_BINDER: {
struct binder_ref *ref;
struct binder_node *node = binder_get_node(proc, fp->binder);
if (node == NULL) {
//创建一个新的Binder实体对象node
node = binder_new_node(proc, fp->binder, fp->cookie);
if (node == NULL) {
return_error = BR_FAILED_REPLY;
goto err_binder_new_node_failed;
}
node->min_priority = fp->flags & FLAT_BINDER_FLAG_PRIORITY_MASK;
node->accept_fds = !!(fp->flags & FLAT_BINDER_FLAG_ACCEPTS_FDS);
}
if (fp->cookie != node->cookie) {
binder_user_error("binder: %d:%d sending u%p "
"node %d, cookie mismatch %p != %p\n",
proc->pid, thread->pid,
fp->binder, node->debug_id,
fp->cookie, node->cookie);
goto err_binder_get_ref_for_node_failed;
}
//在目标进程即Service Manager进程创建一个Binder引用对象来引用Service组件即MediaPlayerService组件
ref = binder_get_ref_for_node(target_proc, node);
if (ref == NULL) {
return_error = BR_FAILED_REPLY;
goto err_binder_get_ref_for_node_failed;
}
if (fp->type == BINDER_TYPE_BINDER)
fp->type = BINDER_TYPE_HANDLE;
else
fp->type = BINDER_TYPE_WEAK_HANDLE;
fp->handle = ref->desc;
binder_inc_ref(ref, fp->type == BINDER_TYPE_HANDLE, &thread->todo);
if (binder_debug_mask & BINDER_DEBUG_TRANSACTION)
printk(KERN_INFO " node %d u%p -> ref %d desc %d\n",
node->debug_id, node->ptr, ref->debug_id, ref->desc);
} break;
case BINDER_TYPE_HANDLE:
case BINDER_TYPE_WEAK_HANDLE: {
struct binder_ref *ref = binder_get_ref(proc, fp->handle);
if (ref == NULL) {
binder_user_error("binder: %d:%d got "
"transaction with invalid "
"handle, %ld\n", proc->pid,
thread->pid, fp->handle);
return_error = BR_FAILED_REPLY;
goto err_binder_get_ref_failed;
}
if (ref->node->proc == target_proc) {
if (fp->type == BINDER_TYPE_HANDLE)
fp->type = BINDER_TYPE_BINDER;
else
fp->type = BINDER_TYPE_WEAK_BINDER;
fp->binder = ref->node->ptr;
fp->cookie = ref->node->cookie;
binder_inc_node(ref->node, fp->type == BINDER_TYPE_BINDER, 0, NULL);
if (binder_debug_mask & BINDER_DEBUG_TRANSACTION)
printk(KERN_INFO " ref %d desc %d -> node %d u%p\n",
ref->debug_id, ref->desc, ref->node->debug_id, ref->node->ptr);
} else {
struct binder_ref *new_ref;
new_ref = binder_get_ref_for_node(target_proc, ref->node);
if (new_ref == NULL) {
return_error = BR_FAILED_REPLY;
goto err_binder_get_ref_for_node_failed;
}
fp->handle = new_ref->desc;
binder_inc_ref(new_ref, fp->type == BINDER_TYPE_HANDLE, NULL);
if (binder_debug_mask & BINDER_DEBUG_TRANSACTION)
printk(KERN_INFO " ref %d desc %d -> ref %d desc %d (node %d)\n",
ref->debug_id, ref->desc, new_ref->debug_id, new_ref->desc, ref->node->debug_id);
}
} break;
case BINDER_TYPE_FD: {
int target_fd;
struct file *file;
if (reply) {
if (!(in_reply_to->flags & TF_ACCEPT_FDS)) {
binder_user_error("binder: %d:%d got reply with fd, %ld, but target does not allow fds\n",
proc->pid, thread->pid, fp->handle);
return_error = BR_FAILED_REPLY;
goto err_fd_not_allowed;
}
} else if (!target_node->accept_fds) {
binder_user_error("binder: %d:%d got transaction with fd, %ld, but target does not allow fds\n",
proc->pid, thread->pid, fp->handle);
return_error = BR_FAILED_REPLY;
goto err_fd_not_allowed;
}
file = fget(fp->handle);
if (file == NULL) {
binder_user_error("binder: %d:%d got transaction with invalid fd, %ld\n",
proc->pid, thread->pid, fp->handle);
return_error = BR_FAILED_REPLY;
goto err_fget_failed;
}
target_fd = task_get_unused_fd_flags(target_proc, O_CLOEXEC);
if (target_fd < 0) {
fput(file);
return_error = BR_FAILED_REPLY;
goto err_get_unused_fd_failed;
}
task_fd_install(target_proc, target_fd, file);
if (binder_debug_mask & BINDER_DEBUG_TRANSACTION)
printk(KERN_INFO " fd %ld -> %d\n", fp->handle, target_fd);
/* TODO: fput? */
fp->handle = target_fd;
} break;
default:
binder_user_error("binder: %d:%d got transactio"
"n with invalid object type, %lx\n",
proc->pid, thread->pid, fp->type);
return_error = BR_FAILED_REPLY;
goto err_bad_object_type;
}
}
if (reply) {
BUG_ON(t->buffer->async_transaction != 0);
binder_pop_transaction(target_thread, in_reply_to);
} else if (!(t->flags & TF_ONE_WAY)) {
BUG_ON(t->buffer->async_transaction != 0);
t->need_reply = 1;
t->from_parent = thread->transaction_stack;
thread->transaction_stack = t;
} else {
BUG_ON(target_node == NULL);
BUG_ON(t->buffer->async_transaction != 1);
if (target_node->has_async_transaction) {
target_list = &target_node->async_todo;
target_wait = NULL;
} else
target_node->has_async_transaction = 1;
}
//将binder_transaction结构体t封装成类型为BINDER_WORK_TRANSACTION的工作项添加到目标进程的todo队列中
t->work.type = BINDER_WORK_TRANSACTION;
list_add_tail(&t->work.entry, target_list);
//将binder_work结构体tcomplete封装成类型为BINDER_WORK_TRANSACTION_COMPLETE的工作项添加到源进程的todo队列中
tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE;
list_add_tail(&tcomplete->entry, &thread->todo);
if (target_wait)
//唤醒目标进程处理事件
wake_up_interruptible(target_wait);
//程序执行到这里，源线程和目标线程会并发去执行各自todo队列中的工作项
return;
err_get_unused_fd_failed:
err_fget_failed:
err_fd_not_allowed:
err_binder_get_ref_for_node_failed:
err_binder_get_ref_failed:
err_binder_new_node_failed:
err_bad_object_type:
err_bad_offset:
err_copy_data_failed:
binder_transaction_buffer_release(target_proc, t->buffer, offp);
t->buffer->transaction = NULL;
binder_free_buf(target_proc, t->buffer);
err_binder_alloc_buf_failed:
kfree(tcomplete);
binder_stats.obj_deleted[BINDER_STAT_TRANSACTION_COMPLETE]++;
err_alloc_tcomplete_failed:
kfree(t);
binder_stats.obj_deleted[BINDER_STAT_TRANSACTION]++;
err_alloc_t_failed:
err_bad_call_stack:
err_empty_call_stack:
err_dead_binder:
err_invalid_target_handle:
err_no_context_mgr_node:
if (binder_debug_mask & BINDER_DEBUG_FAILED_TRANSACTION)
printk(KERN_INFO "binder: %d:%d transaction failed %d, size"
"%zd-%zd\n",
proc->pid, thread->pid, return_error,
tr->data_size, tr->offsets_size);
{
struct binder_transaction_log_entry *fe;
fe = binder_transaction_log_add(&binder_transaction_log_failed);
*fe = *e;
}
BUG_ON(thread->return_error != BR_OK);
if (in_reply_to) {
thread->return_error = BR_TRANSACTION_COMPLETE;
binder_send_failed_reply(in_reply_to, return_error);
} else
thread->return_error = return_error;
}
static void
binder_pop_transaction(
struct binder_thread *target_thread, struct binder_transaction *t)
{
if (target_thread) {
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;
}
t->need_reply = 0;
if (t->buffer)
t->buffer->transaction = NULL;
kfree(t);
binder_stats.obj_deleted[BINDER_STAT_TRANSACTION]++;
}