/* binder.c * * Android IPC Subsystem * * Copyright (C) 2007-2008 Google, Inc. * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * */ /* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "binder_alloc.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; #define BINDER_DEBUG_ENTRY(name) \ static int binder_##name##_open(struct inode *inode, struct file *file) \ { \ return single_open(file, binder_##name##_show, inode->i_private); \ } \ \ static const struct file_operations binder_##name##_fops = { \ .owner = THIS_MODULE, \ .open = binder_##name##_open, \ .read = seq_read, \ .llseek = seq_lseek, \ .release = single_release, \ } static int binder_proc_show(struct seq_file *m, void *unused); BINDER_DEBUG_ENTRY(proc); /* This is only defined in include/asm-arm/sizes.h */ #ifndef SZ_1K #define SZ_1K 0x400 #endif #ifndef SZ_4M #define SZ_4M 0x400000 #endif #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); static 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(x); \ } while (0) #define binder_user_error(x...) \ do { \ if (binder_debug_mask & BINDER_DEBUG_USER_ERROR) \ pr_info(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) enum binder_stat_types { BINDER_STAT_PROC, BINDER_STAT_THREAD, BINDER_STAT_NODE, BINDER_STAT_REF, BINDER_STAT_DEATH, BINDER_STAT_TRANSACTION, BINDER_STAT_TRANSACTION_COMPLETE, BINDER_STAT_COUNT }; struct binder_stats { atomic_t br[_IOC_NR(BR_FAILED_REPLY) + 1]; atomic_t bc[_IOC_NR(BC_REPLY_SG) + 1]; atomic_t obj_created[BINDER_STAT_COUNT]; atomic_t obj_deleted[BINDER_STAT_COUNT]; }; 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_entry { int debug_id; int debug_id_done; int call_type; int from_proc; int from_thread; int target_handle; int to_proc; int to_thread; int to_node; int data_size; int offsets_size; int return_error_line; uint32_t return_error; uint32_t return_error_param; const char *context_name; }; struct binder_transaction_log { atomic_t cur; bool full; struct binder_transaction_log_entry entry[32]; }; static struct binder_transaction_log binder_transaction_log; static 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; } struct binder_context { struct binder_node *binder_context_mgr_node; struct mutex context_mgr_node_lock; kuid_t binder_context_mgr_uid; const char *name; }; struct binder_device { struct hlist_node hlist; struct miscdevice miscdev; struct binder_context context; }; /** * struct binder_work - work enqueued on a worklist * @entry: node enqueued on list * @type: type of work to be performed * * There are separate work lists for proc, thread, and node (async). */ struct binder_work { struct list_head entry; enum { BINDER_WORK_TRANSACTION = 1, BINDER_WORK_TRANSACTION_COMPLETE, BINDER_WORK_RETURN_ERROR, BINDER_WORK_NODE, BINDER_WORK_DEAD_BINDER, BINDER_WORK_DEAD_BINDER_AND_CLEAR, BINDER_WORK_CLEAR_DEATH_NOTIFICATION, } type; }; struct binder_error { struct binder_work work; uint32_t cmd; }; /** * struct binder_node - binder node bookkeeping * @debug_id: unique ID for debugging * (invariant after initialized) * @lock: lock for node fields * @work: worklist element for node work * (protected by @proc->inner_lock) * @rb_node: element for proc->nodes tree * (protected by @proc->inner_lock) * @dead_node: element for binder_dead_nodes list * (protected by binder_dead_nodes_lock) * @proc: binder_proc that owns this node * (invariant after initialized) * @refs: list of references on this node * (protected by @lock) * @internal_strong_refs: used to take strong references when * initiating a transaction * (protected by @proc->inner_lock if @proc * and by @lock) * @local_weak_refs: weak user refs from local process * (protected by @proc->inner_lock if @proc * and by @lock) * @local_strong_refs: strong user refs from local process * (protected by @proc->inner_lock if @proc * and by @lock) * @tmp_refs: temporary kernel refs * (protected by @proc->inner_lock while @proc * is valid, and by binder_dead_nodes_lock * if @proc is NULL. During inc/dec and node release * it is also protected by @lock to provide safety * as the node dies and @proc becomes NULL) * @ptr: userspace pointer for node * (invariant, no lock needed) * @cookie: userspace cookie for node * (invariant, no lock needed) * @has_strong_ref: userspace notified of strong ref * (protected by @proc->inner_lock if @proc * and by @lock) * @pending_strong_ref: userspace has acked notification of strong ref * (protected by @proc->inner_lock if @proc * and by @lock) * @has_weak_ref: userspace notified of weak ref * (protected by @proc->inner_lock if @proc * and by @lock) * @pending_weak_ref: userspace has acked notification of weak ref * (protected by @proc->inner_lock if @proc * and by @lock) * @has_async_transaction: async transaction to node in progress * (protected by @lock) * @accept_fds: file descriptor operations supported for node * (invariant after initialized) * @min_priority: minimum scheduling priority * (invariant after initialized) * @async_todo: list of async work items * (protected by @proc->inner_lock) * * Bookkeeping structure for binder nodes. */ struct binder_node { int debug_id; spinlock_t lock; struct binder_work work; union { struct rb_node rb_node; struct hlist_node dead_node; }; struct binder_proc *proc; struct hlist_head refs; int internal_strong_refs; int local_weak_refs; int local_strong_refs; int tmp_refs; binder_uintptr_t ptr; binder_uintptr_t cookie; struct { /* * bitfield elements protected by * proc inner_lock */ u8 has_strong_ref:1; u8 pending_strong_ref:1; u8 has_weak_ref:1; u8 pending_weak_ref:1; }; struct { /* * invariant after initialization */ u8 accept_fds:1; u8 min_priority; }; bool has_async_transaction; struct list_head async_todo; }; struct binder_ref_death { /** * @work: worklist element for death notifications * (protected by inner_lock of the proc that * this ref belongs to) */ struct binder_work work; binder_uintptr_t cookie; }; /** * struct binder_ref_data - binder_ref counts and id * @debug_id: unique ID for the ref * @desc: unique userspace handle for ref * @strong: strong ref count (debugging only if not locked) * @weak: weak ref count (debugging only if not locked) * * Structure to hold ref count and ref id information. Since * the actual ref can only be accessed with a lock, this structure * is used to return information about the ref to callers of * ref inc/dec functions. */ struct binder_ref_data { int debug_id; uint32_t desc; int strong; int weak; }; /** * struct binder_ref - struct to track references on nodes * @data: binder_ref_data containing id, handle, and current refcounts * @rb_node_desc: node for lookup by @data.desc in proc's rb_tree * @rb_node_node: node for lookup by @node in proc's rb_tree * @node_entry: list entry for node->refs list in target node * (protected by @node->lock) * @proc: binder_proc containing ref * @node: binder_node of target node. When cleaning up a * ref for deletion in binder_cleanup_ref, a non-NULL * @node indicates the node must be freed * @death: pointer to death notification (ref_death) if requested * (protected by @node->lock) * * Structure to track references from procA to target node (on procB). This * structure is unsafe to access without holding @proc->outer_lock. */ struct binder_ref { /* Lookups needed: */ /* node + proc => ref (transaction) */ /* desc + proc => ref (transaction, inc/dec ref) */ /* node => refs + procs (proc exit) */ struct binder_ref_data data; struct rb_node rb_node_desc; struct rb_node rb_node_node; struct hlist_node node_entry; struct binder_proc *proc; struct binder_node *node; struct binder_ref_death *death; }; enum binder_deferred_state { BINDER_DEFERRED_PUT_FILES = 0x01, BINDER_DEFERRED_FLUSH = 0x02, BINDER_DEFERRED_RELEASE = 0x04, }; /** * struct binder_proc - binder process bookkeeping * @proc_node: element for binder_procs list * @threads: rbtree of binder_threads in this proc * (protected by @inner_lock) * @nodes: rbtree of binder nodes associated with * this proc ordered by node->ptr * (protected by @inner_lock) * @refs_by_desc: rbtree of refs ordered by ref->desc * (protected by @outer_lock) * @refs_by_node: rbtree of refs ordered by ref->node * (protected by @outer_lock) * @waiting_threads: threads currently waiting for proc work * (protected by @inner_lock) * @pid PID of group_leader of process * (invariant after initialized) * @tsk task_struct for group_leader of process * (invariant after initialized) * @files files_struct for process * (protected by @files_lock) * @files_lock mutex to protect @files * @deferred_work_node: element for binder_deferred_list * (protected by binder_deferred_lock) * @deferred_work: bitmap of deferred work to perform * (protected by binder_deferred_lock) * @is_dead: process is dead and awaiting free * when outstanding transactions are cleaned up * (protected by @inner_lock) * @todo: list of work for this process * (protected by @inner_lock) * @stats: per-process binder statistics * (atomics, no lock needed) * @delivered_death: list of delivered death notification * (protected by @inner_lock) * @max_threads: cap on number of binder threads * (protected by @inner_lock) * @requested_threads: number of binder threads requested but not * yet started. In current implementation, can * only be 0 or 1. * (protected by @inner_lock) * @requested_threads_started: number binder threads started * (protected by @inner_lock) * @tmp_ref: temporary reference to indicate proc is in use * (protected by @inner_lock) * @default_priority: default scheduler priority * (invariant after initialized) * @debugfs_entry: debugfs node * @alloc: binder allocator bookkeeping * @context: binder_context for this proc * (invariant after initialized) * @inner_lock: can nest under outer_lock and/or node lock * @outer_lock: no nesting under innor or node lock * Lock order: 1) outer, 2) node, 3) inner * * Bookkeeping structure for binder processes */ struct binder_proc { struct hlist_node proc_node; struct rb_root threads; struct rb_root nodes; struct rb_root refs_by_desc; struct rb_root refs_by_node; struct list_head waiting_threads; int pid; struct task_struct *tsk; struct files_struct *files; struct mutex files_lock; struct hlist_node deferred_work_node; int deferred_work; bool is_dead; struct list_head todo; struct binder_stats stats; struct list_head delivered_death; int max_threads; int requested_threads; int requested_threads_started; int tmp_ref; long default_priority; struct dentry *debugfs_entry; struct binder_alloc alloc; struct binder_context *context; spinlock_t inner_lock; spinlock_t outer_lock; }; 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, }; /** * struct binder_thread - binder thread bookkeeping * @proc: binder process for this thread * (invariant after initialization) * @rb_node: element for proc->threads rbtree * (protected by @proc->inner_lock) * @waiting_thread_node: element for @proc->waiting_threads list * (protected by @proc->inner_lock) * @pid: PID for this thread * (invariant after initialization) * @looper: bitmap of looping state * (only accessed by this thread) * @looper_needs_return: looping thread needs to exit driver * (no lock needed) * @transaction_stack: stack of in-progress transactions for this thread * (protected by @proc->inner_lock) * @todo: list of work to do for this thread * (protected by @proc->inner_lock) * @process_todo: whether work in @todo should be processed * (protected by @proc->inner_lock) * @return_error: transaction errors reported by this thread * (only accessed by this thread) * @reply_error: transaction errors reported by target thread * (protected by @proc->inner_lock) * @wait: wait queue for thread work * @stats: per-thread statistics * (atomics, no lock needed) * @tmp_ref: temporary reference to indicate thread is in use * (atomic since @proc->inner_lock cannot * always be acquired) * @is_dead: thread is dead and awaiting free * when outstanding transactions are cleaned up * (protected by @proc->inner_lock) * * Bookkeeping structure for binder threads. */ struct binder_thread { struct binder_proc *proc; struct rb_node rb_node; struct list_head waiting_thread_node; int pid; int looper; /* only modified by this thread */ bool looper_need_return; /* can be written by other thread */ struct binder_transaction *transaction_stack; struct list_head todo; bool process_todo; struct binder_error return_error; struct binder_error reply_error; wait_queue_head_t wait; struct binder_stats stats; atomic_t tmp_ref; bool is_dead; }; struct binder_transaction { int debug_id; struct binder_work work; struct binder_thread *from; struct binder_transaction *from_parent; struct binder_proc *to_proc; struct binder_thread *to_thread; struct binder_transaction *to_parent; unsigned need_reply:1; /* unsigned is_dead:1; */ /* not used at the moment */ struct binder_buffer *buffer; unsigned int code; unsigned int flags; long priority; long saved_priority; kuid_t sender_euid; /** * @lock: protects @from, @to_proc, and @to_thread * * @from, @to_proc, and @to_thread can be set to NULL * during thread teardown */ spinlock_t lock; }; /** * 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) { 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) { 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) { 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) { 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) { 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) { 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) { binder_debug(BINDER_DEBUG_SPINLOCKS, "%s: line=%d\n", __func__, line); spin_lock(&node->lock); if (node->proc) binder_inner_proc_lock(node->proc); } /** * 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) { struct binder_proc *proc = node->proc; binder_debug(BINDER_DEBUG_SPINLOCKS, "%s: line=%d\n", __func__, line); if (proc) binder_inner_proc_unlock(proc); 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) { 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) { 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; } /** * binder_dequeue_work_head() - Dequeues the item at head of list * @proc: binder_proc associated with list * @list: list to dequeue head * * Removes the head of the list if there are items on the list * * Return: pointer dequeued binder_work, NULL if list was empty */ static struct binder_work *binder_dequeue_work_head( struct binder_proc *proc, struct list_head *list) { struct binder_work *w; binder_inner_proc_lock(proc); w = binder_dequeue_work_head_ilocked(list); binder_inner_proc_unlock(proc); 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 int task_get_unused_fd_flags(struct binder_proc *proc, int flags) { unsigned long rlim_cur; unsigned long irqs; int ret; mutex_lock(&proc->files_lock); if (proc->files == NULL) { ret = -ESRCH; goto err; } if (!lock_task_sighand(proc->tsk, &irqs)) { ret = -EMFILE; goto err; } rlim_cur = task_rlimit(proc->tsk, RLIMIT_NOFILE); unlock_task_sighand(proc->tsk, &irqs); ret = __alloc_fd(proc->files, 0, rlim_cur, flags); err: mutex_unlock(&proc->files_lock); return ret; } /* * copied from fd_install */ static void task_fd_install( struct binder_proc *proc, unsigned int fd, struct file *file) { mutex_lock(&proc->files_lock); if (proc->files) __fd_install(proc->files, fd, file); mutex_unlock(&proc->files_lock); } /* * copied from sys_close */ static long task_close_fd(struct binder_proc *proc, unsigned int fd) { int retval; mutex_lock(&proc->files_lock); if (proc->files == NULL) { retval = -ESRCH; goto err; } retval = __close_fd(proc->files, fd); /* can't restart close syscall because file table entry was cleared */ if (unlikely(retval == -ERESTARTSYS || retval == -ERESTARTNOINTR || retval == -ERESTARTNOHAND || retval == -ERESTART_RESTARTBLOCK)) retval = -EINTR; err: mutex_unlock(&proc->files_lock); return retval; } 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); 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) { binder_dequeue_work_ilocked(&node->work); /* * Note: this function is the only place where we queue * directly to a thread->todo without using the * corresponding binder_enqueue_thread_work() helper * functions; in this case it's ok to not set the * process_todo flag, since we know this node work will * always be followed by other work that starts queue * processing: in case of synchronous transactions, a * BR_REPLY or BR_ERROR; in case of oneway * transactions, a BR_TRANSACTION_COMPLETE. */ binder_enqueue_work_ilocked(&node->work, target_list); } } 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); node->tmp_refs--; BUG_ON(node->tmp_refs < 0); if (!node->proc) spin_unlock(&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) { struct binder_thread *from; from = binder_get_txn_from(t); if (!from) return NULL; binder_inner_proc_lock(from->proc); if (t->from) { BUG_ON(from != t->from); return from; } binder_inner_proc_unlock(from->proc); binder_thread_dec_tmpref(from); return NULL; } static void binder_free_transaction(struct binder_transaction *t) { if (t->buffer) t->buffer->transaction = NULL; 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; } 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_validate_object() - checks for a valid metadata object in a buffer. * @buffer: binder_buffer that we're parsing. * @offset: offset in the buffer at which to validate an object. * * Return: If there's a valid metadata object at @offset in @buffer, the * size of that object. Otherwise, it returns zero. */ static size_t binder_validate_object(struct binder_buffer *buffer, u64 offset) { /* Check if we can read a header first */ struct binder_object_header *hdr; size_t object_size = 0; if (buffer->data_size < sizeof(*hdr) || offset > buffer->data_size - sizeof(*hdr) || !IS_ALIGNED(offset, sizeof(u32))) return 0; /* Ok, now see if we can read a complete object. */ hdr = (struct binder_object_header *)(buffer->data + offset); 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. * @b: binder_buffer containing the object * @index: index in offset array at which the binder_buffer_object is * located * @start: points to the start of the offset array * @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. */ static struct binder_buffer_object *binder_validate_ptr(struct binder_buffer *b, binder_size_t index, binder_size_t *start, binder_size_t num_valid) { struct binder_buffer_object *buffer_obj; binder_size_t *offp; if (index >= num_valid) return NULL; offp = start + index; buffer_obj = (struct binder_buffer_object *)(b->data + *offp); if (buffer_obj->hdr.type != BINDER_TYPE_PTR) return NULL; return buffer_obj; } /** * binder_validate_fixup() - validates pointer/fd fixups happen in order. * @b: transaction buffer * @objects_start start of objects buffer * @buffer: binder_buffer_object in which to fix up * @offset: start offset in @buffer to fix up * @last_obj: last binder_buffer_object that we fixed up in * @last_min_offset: minimum fixup offset in @last_obj * * 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_buffer *b, binder_size_t *objects_start, struct binder_buffer_object *buffer, binder_size_t fixup_offset, struct binder_buffer_object *last_obj, binder_size_t last_min_offset) { if (!last_obj) { /* Nothing to fix up in */ return false; } while (last_obj != buffer) { /*