[RFC 18/19] binder: add detailed IOCTL API specifications

Sasha Levin
2025-06-14T13:49:17Z

Add kernel API specifications to the binder driver using the IOCTL
specification framework. This provides detailed documentation and
enables runtime validation of all binder IOCTL interfaces.

Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/android/binder.c | 758 +++++++++++++++++++++++++++++++++++++++
1 file changed, 758 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index c463ca4a8fff8..975f07216724b 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -67,6 +67,8 @@
#include <linux/task_work.h>
#include <linux/sizes.h>
#include <linux/ktime.h>
+#include <linux/ioctl_api_spec.h>
+#include <linux/kernel_api_spec.h>

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

@@ -6930,6 +6932,7 @@ static int transaction_log_show(struct seq_file *m, void *unused)
return 0;
}

+/* Define the actual binder_fops structure */
const struct file_operations binder_fops = {
.owner = THIS_MODULE,
.poll = binder_poll,
@@ -6941,6 +6944,751 @@ const struct file_operations binder_fops = {
.release = binder_release,
};

+/* Define wrapper for KAPI validation */
+#ifdef CONFIG_KAPI_RUNTIME_CHECKS
+static struct file_operations __kapi_wrapped_binder_fops;
+static struct kapi_fops_wrapper __kapi_wrapper_binder_fops;
+
+static void kapi_init_fops_binder_fops(void)
+{
+ if (binder_fops.unlocked_ioctl) {
+ __kapi_wrapped_binder_fops = binder_fops;
+ __kapi_wrapper_binder_fops.real_fops = &binder_fops;
+ __kapi_wrapper_binder_fops.wrapped_fops = &__kapi_wrapped_binder_fops;
+ __kapi_wrapper_binder_fops.real_ioctl = binder_fops.unlocked_ioctl;
+ __kapi_wrapped_binder_fops.unlocked_ioctl = kapi_ioctl_validation_wrapper;
+ kapi_register_wrapper(&__kapi_wrapper_binder_fops);
+ }
+}
+#else
+static inline void kapi_init_fops_binder_fops(void) {}
+#endif
+
+/* IOCTL API Specifications for Binder */
+
+static const struct kapi_ioctl_spec binder_write_read_spec = {
+ .cmd = BINDER_WRITE_READ,
+ .cmd_name = "BINDER_WRITE_READ",
+ .input_size = sizeof(struct binder_write_read),
+ .output_size = sizeof(struct binder_write_read),
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_write_read",
+ KAPI_DESCRIPTION("Perform read/write operations on binder")
+ KAPI_LONG_DESC("Main workhorse of binder IPC. Allows writing commands to "
+ "binder driver and reading responses. Commands are encoded "
+ "in a special protocol format. Both read and write operations "
+ "can be performed in a single ioctl call.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "write_size", "binder_size_t", "Bytes to write")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = SZ_4M, /* Reasonable limit for IPC */
+ KAPI_PARAM_END
+
+ KAPI_PARAM(1, "write_consumed", "binder_size_t", "Bytes consumed by driver")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = SZ_4M,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(2, "write_buffer", "binder_uintptr_t", "User buffer with commands")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN | KAPI_PARAM_USER)
+ .type = KAPI_TYPE_USER_PTR,
+ .size_param_idx = 0,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(3, "read_size", "binder_size_t", "Bytes to read")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = SZ_4M,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(4, "read_consumed", "binder_size_t", "Bytes consumed by driver")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = SZ_4M,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(5, "read_buffer", "binder_uintptr_t", "User buffer for responses")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT | KAPI_PARAM_USER)
+ .type = KAPI_TYPE_USER_PTR,
+ .size_param_idx = 3,
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EFAULT, -EINVAL, -EAGAIN, -EINTR,
+ -ENOMEM, -ECONNREFUSED},
+ .error_count = 6,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EFAULT, "EFAULT", "Failed to copy data to/from user space",
+ "Check buffer pointers are valid user space addresses")
+ KAPI_ERROR(1, -EINVAL, "EINVAL", "Invalid parameters",
+ "Buffer sizes or commands are invalid")
+ KAPI_ERROR(2, -EAGAIN, "EAGAIN", "Try again",
+ "Non-blocking read with no data available")
+ KAPI_ERROR(3, -EINTR, "EINTR", "Interrupted by signal",
+ "Operation interrupted, should be retried")
+ KAPI_ERROR(4, -ENOMEM, "ENOMEM", "Out of memory",
+ "Unable to allocate memory for operation")
+ KAPI_ERROR(5, -ECONNREFUSED, "ECONNREFUSED", "Connection refused",
+ "Process is being destroyed, no further operations allowed")
+
+ .error_count = 6,
+ .param_count = 6,
+ .since_version = "3.0",
+ .notes = "This is the primary interface for binder IPC. Most other "
+ "ioctls are for configuration and management.",
+
+ /* Structure specifications */
+ KAPI_STRUCT_SPEC(0, binder_write_read, "Read/write operation structure")
+ KAPI_STRUCT_SIZE(sizeof(struct binder_write_read), __alignof__(struct binder_write_read))
+ KAPI_STRUCT_FIELD_COUNT(6)
+
+ KAPI_STRUCT_FIELD(0, "write_size", KAPI_TYPE_UINT, "binder_size_t",
+ "Number of bytes to write")
+ KAPI_FIELD_OFFSET(offsetof(struct binder_write_read, write_size))
+ KAPI_FIELD_SIZE(sizeof(binder_size_t))
+ KAPI_STRUCT_FIELD_END
+
+ KAPI_STRUCT_FIELD(1, "write_consumed", KAPI_TYPE_UINT, "binder_size_t",
+ "Number of bytes consumed by driver")
+ KAPI_FIELD_OFFSET(offsetof(struct binder_write_read, write_consumed))
+ KAPI_FIELD_SIZE(sizeof(binder_size_t))
+ KAPI_STRUCT_FIELD_END
+
+ KAPI_STRUCT_FIELD(2, "write_buffer", KAPI_TYPE_PTR, "binder_uintptr_t",
+ "Pointer to write buffer")
+ KAPI_FIELD_OFFSET(offsetof(struct binder_write_read, write_buffer))
+ KAPI_FIELD_SIZE(sizeof(binder_uintptr_t))
+ KAPI_STRUCT_FIELD_END
+
+ KAPI_STRUCT_FIELD(3, "read_size", KAPI_TYPE_UINT, "binder_size_t",
+ "Number of bytes to read")
+ KAPI_FIELD_OFFSET(offsetof(struct binder_write_read, read_size))
+ KAPI_FIELD_SIZE(sizeof(binder_size_t))
+ KAPI_STRUCT_FIELD_END
+
+ KAPI_STRUCT_FIELD(4, "read_consumed", KAPI_TYPE_UINT, "binder_size_t",
+ "Number of bytes consumed by driver")
+ KAPI_FIELD_OFFSET(offsetof(struct binder_write_read, read_consumed))
+ KAPI_FIELD_SIZE(sizeof(binder_size_t))
+ KAPI_STRUCT_FIELD_END
+
+ KAPI_STRUCT_FIELD(5, "read_buffer", KAPI_TYPE_PTR, "binder_uintptr_t",
+ "Pointer to read buffer")
+ KAPI_FIELD_OFFSET(offsetof(struct binder_write_read, read_buffer))
+ KAPI_FIELD_SIZE(sizeof(binder_uintptr_t))
+ KAPI_STRUCT_FIELD_END
+ KAPI_STRUCT_SPEC_END
+
+ KAPI_STRUCT_SPEC_COUNT(1)
+
+ /* Side effects */
+ KAPI_SIDE_EFFECT(0, KAPI_EFFECT_MODIFY_STATE | KAPI_EFFECT_NETWORK,
+ "binder transaction queue",
+ "Enqueues transactions or commands to target process")
+ KAPI_EFFECT_CONDITION("write_size > 0")
+ KAPI_SIDE_EFFECT_END
+
+ KAPI_SIDE_EFFECT(1, KAPI_EFFECT_MODIFY_STATE | KAPI_EFFECT_SCHEDULE,
+ "process state",
+ "May block waiting for incoming transactions")
+ KAPI_EFFECT_CONDITION("read_size > 0 && no data available")
+ KAPI_SIDE_EFFECT_END
+
+ KAPI_SIDE_EFFECT(2, KAPI_EFFECT_RESOURCE_CREATE,
+ "binder nodes/refs",
+ "May create or destroy binder nodes and references")
+ KAPI_EFFECT_CONDITION("specific commands")
+ KAPI_EFFECT_REVERSIBLE
+ KAPI_SIDE_EFFECT_END
+
+ KAPI_SIDE_EFFECT(3, KAPI_EFFECT_SIGNAL_SEND,
+ "target process",
+ "May trigger death notifications to linked processes")
+ KAPI_EFFECT_CONDITION("death notification")
+ KAPI_SIDE_EFFECT_END
+
+ KAPI_SIDE_EFFECT_COUNT(4)
+
+ /* State transitions */
+ KAPI_STATE_TRANS(0, "transaction",
+ "pending in sender", "queued in target",
+ "Transaction moves from sender to target's queue")
+ KAPI_STATE_TRANS_COND("BC_TRANSACTION command")
+ KAPI_STATE_TRANS_END
+
+ KAPI_STATE_TRANS(1, "thread state",
+ "running", "waiting for work",
+ "Thread blocks waiting for incoming transactions")
+ KAPI_STATE_TRANS_COND("read with no work available")
+ KAPI_STATE_TRANS_END
+
+ KAPI_STATE_TRANS(2, "binder ref",
+ "active", "released",
+ "Reference count decremented, may trigger cleanup")
+ KAPI_STATE_TRANS_COND("BC_RELEASE command")
+ KAPI_STATE_TRANS_END
+
+ KAPI_STATE_TRANS_COUNT(3)
+ },
+};
+
+static const struct kapi_ioctl_spec binder_set_max_threads_spec = {
+ .cmd = BINDER_SET_MAX_THREADS,
+ .cmd_name = "BINDER_SET_MAX_THREADS",
+ .input_size = sizeof(__u32),
+ .output_size = 0,
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_set_max_threads",
+ KAPI_DESCRIPTION("Set maximum number of binder threads")
+ KAPI_LONG_DESC("Sets the maximum number of threads that the binder driver "
+ "will request this process to spawn for handling incoming "
+ "transactions. The driver sends BR_SPAWN_LOOPER when it needs "
+ "more threads.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "max_threads", "__u32", "Maximum number of threads")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = INT_MAX,
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EINVAL, -EFAULT},
+ .error_count = 2,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EINVAL, "EINVAL", "Invalid thread count",
+ "Thread count exceeds system limits")
+ KAPI_ERROR(1, -EFAULT, "EFAULT", "Failed to copy from user",
+ "Invalid user pointer provided")
+
+ .error_count = 2,
+ .param_count = 1,
+ .since_version = "3.0",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_set_context_mgr_spec = {
+ .cmd = BINDER_SET_CONTEXT_MGR,
+ .cmd_name = "BINDER_SET_CONTEXT_MGR",
+ .input_size = 0,
+ .output_size = 0,
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_set_context_mgr",
+ KAPI_DESCRIPTION("Become the context manager (handle 0)")
+ KAPI_LONG_DESC("Registers the calling process as the context manager for "
+ "this binder domain. The context manager has special handle 0 "
+ "and typically implements the service manager. Only one process "
+ "per binder domain can be the context manager.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EBUSY, -EPERM, -ENOMEM},
+ .error_count = 3,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EBUSY, "EBUSY", "Context manager already set",
+ "Another process is already the context manager")
+ KAPI_ERROR(1, -EPERM, "EPERM", "Permission denied",
+ "Caller lacks permission or wrong UID")
+ KAPI_ERROR(2, -ENOMEM, "ENOMEM", "Out of memory",
+ "Unable to allocate context manager node")
+
+ .error_count = 3,
+ .param_count = 0,
+ .since_version = "3.0",
+ .notes = "Requires CAP_SYS_NICE or proper SELinux permissions",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_set_context_mgr_ext_spec = {
+ .cmd = BINDER_SET_CONTEXT_MGR_EXT,
+ .cmd_name = "BINDER_SET_CONTEXT_MGR_EXT",
+ .input_size = sizeof(struct flat_binder_object),
+ .output_size = 0,
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_set_context_mgr_ext",
+ KAPI_DESCRIPTION("Become context manager with extended info")
+ KAPI_LONG_DESC("Extended version of BINDER_SET_CONTEXT_MGR that allows "
+ "specifying additional properties of the context manager "
+ "through a flat_binder_object structure.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "object", "struct flat_binder_object", "Context manager properties")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_STRUCT,
+ .size = sizeof(struct flat_binder_object),
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EINVAL, -EFAULT, -EBUSY, -EPERM, -ENOMEM},
+ .error_count = 5,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EINVAL, "EINVAL", "Invalid parameters",
+ "Invalid flat_binder_object structure")
+ KAPI_ERROR(1, -EFAULT, "EFAULT", "Failed to copy from user",
+ "Invalid user pointer provided")
+ KAPI_ERROR(2, -EBUSY, "EBUSY", "Context manager already set",
+ "Another process is already the context manager")
+ KAPI_ERROR(3, -EPERM, "EPERM", "Permission denied",
+ "Caller lacks permission or wrong UID")
+ KAPI_ERROR(4, -ENOMEM, "ENOMEM", "Out of memory",
+ "Unable to allocate context manager node")
+
+ .error_count = 5,
+ .param_count = 1,
+ .since_version = "4.14",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_thread_exit_spec = {
+ .cmd = BINDER_THREAD_EXIT,
+ .cmd_name = "BINDER_THREAD_EXIT",
+ .input_size = 0,
+ .output_size = 0,
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_thread_exit",
+ KAPI_DESCRIPTION("Exit binder thread")
+ KAPI_LONG_DESC("Notifies the binder driver that this thread is exiting. "
+ "The driver will clean up any pending transactions and "
+ "remove the thread from the thread pool.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){},
+ .error_count = 0,
+ KAPI_RETURN_END
+
+ .error_count = 0,
+ .param_count = 0,
+ .since_version = "3.0",
+ .notes = "Should be called before thread termination to ensure clean shutdown",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_version_spec = {
+ .cmd = BINDER_VERSION,
+ .cmd_name = "BINDER_VERSION",
+ .input_size = 0,
+ .output_size = sizeof(struct binder_version),
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_version",
+ KAPI_DESCRIPTION("Get binder protocol version")
+ KAPI_LONG_DESC("Returns the current binder protocol version supported "
+ "by the driver. Used for compatibility checking.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "protocol_version", "__s32", "Binder protocol version")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_INT,
+ .constraint_type = KAPI_CONSTRAINT_ENUM,
+ .enum_values = (const s64[]){BINDER_CURRENT_PROTOCOL_VERSION},
+ .enum_count = 1,
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EINVAL, -EFAULT},
+ .error_count = 2,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EINVAL, "EINVAL", "Invalid version structure",
+ "Invalid user pointer for version structure")
+ KAPI_ERROR(1, -EFAULT, "EFAULT", "Failed to copy to user",
+ "Unable to write version to user space")
+
+ .error_count = 2,
+ .param_count = 1,
+ .since_version = "3.0",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_get_node_info_for_ref_spec = {
+ .cmd = BINDER_GET_NODE_INFO_FOR_REF,
+ .cmd_name = "BINDER_GET_NODE_INFO_FOR_REF",
+ .input_size = sizeof(struct binder_node_info_for_ref),
+ .output_size = sizeof(struct binder_node_info_for_ref),
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_get_node_info_for_ref",
+ KAPI_DESCRIPTION("Get node information for a reference")
+ KAPI_LONG_DESC("Retrieves information about a binder node given its handle. "
+ "Returns the current strong and weak reference counts.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "handle", "__u32", "Binder handle")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_UINT,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(1, "strong_count", "__u32", "Strong reference count")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(2, "weak_count", "__u32", "Weak reference count")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EINVAL, -EFAULT, -ENOENT},
+ .error_count = 3,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EINVAL, "EINVAL", "Invalid parameters",
+ "Reserved fields must be zero")
+ KAPI_ERROR(1, -EFAULT, "EFAULT", "Failed to copy data",
+ "Invalid user pointer provided")
+ KAPI_ERROR(2, -ENOENT, "ENOENT", "Handle not found",
+ "No node exists for the given handle")
+
+ .error_count = 3,
+ .param_count = 3,
+ .since_version = "4.14",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_get_node_debug_info_spec = {
+ .cmd = BINDER_GET_NODE_DEBUG_INFO,
+ .cmd_name = "BINDER_GET_NODE_DEBUG_INFO",
+ .input_size = sizeof(struct binder_node_debug_info),
+ .output_size = sizeof(struct binder_node_debug_info),
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_get_node_debug_info",
+ KAPI_DESCRIPTION("Get debug info for binder nodes")
+ KAPI_LONG_DESC("Iterates through all binder nodes in the process. "
+ "Start with ptr=NULL to get first node, then use "
+ "returned ptr for next call. Returns ptr=0 when done.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "ptr", "binder_uintptr_t", "Node pointer (NULL for first)")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_INOUT)
+ .type = KAPI_TYPE_PTR,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(1, "cookie", "binder_uintptr_t", "Node cookie value")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(2, "has_strong_ref", "__u32", "Has strong references")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = 1,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(3, "has_weak_ref", "__u32", "Has weak references")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = 1,
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EFAULT, -EINVAL},
+ .error_count = 2,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EFAULT, "EFAULT", "Failed to copy data",
+ "Invalid user pointer provided")
+ KAPI_ERROR(1, -EINVAL, "EINVAL", "Invalid node pointer",
+ "Provided ptr is not a valid node")
+
+ .error_count = 2,
+ .param_count = 4,
+ .since_version = "4.14",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_freeze_spec = {
+ .cmd = BINDER_FREEZE,
+ .cmd_name = "BINDER_FREEZE",
+ .input_size = sizeof(struct binder_freeze_info),
+ .output_size = 0,
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_freeze",
+ KAPI_DESCRIPTION("Freeze or unfreeze a binder process")
+ KAPI_LONG_DESC("Controls whether a process can receive binder transactions. "
+ "When frozen, new transactions are blocked. Can wait for "
+ "existing transactions to complete with timeout.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "pid", "__u32", "Process ID to freeze/unfreeze")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 1,
+ .max_value = PID_MAX_LIMIT,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(1, "enable", "__u32", "1 to freeze, 0 to unfreeze")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = 1,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(2, "timeout_ms", "__u32", "Timeout in milliseconds (0 = no wait)")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = 60000, /* 1 minute max */
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EINVAL, -EAGAIN, -EFAULT, -ENOMEM},
+ .error_count = 4,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EINVAL, "EINVAL", "Invalid process",
+ "Process not found or invalid parameters")
+ KAPI_ERROR(1, -EAGAIN, "EAGAIN", "Timeout waiting for transactions",
+ "Existing transactions did not complete within timeout")
+ KAPI_ERROR(2, -EFAULT, "EFAULT", "Failed to copy from user",
+ "Invalid user pointer provided")
+ KAPI_ERROR(3, -ENOMEM, "ENOMEM", "Out of memory",
+ "Unable to allocate memory for freeze operation")
+
+ .error_count = 4,
+ .param_count = 3,
+ .since_version = "5.9",
+ .notes = "Requires appropriate permissions to freeze other processes",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_get_frozen_info_spec = {
+ .cmd = BINDER_GET_FROZEN_INFO,
+ .cmd_name = "BINDER_GET_FROZEN_INFO",
+ .input_size = sizeof(struct binder_frozen_status_info),
+ .output_size = sizeof(struct binder_frozen_status_info),
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_get_frozen_info",
+ KAPI_DESCRIPTION("Get frozen status of a process")
+ KAPI_LONG_DESC("Queries whether a process is frozen and if it has "
+ "received transactions while frozen. Useful for "
+ "debugging frozen process issues.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "pid", "__u32", "Process ID to query")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 1,
+ .max_value = PID_MAX_LIMIT,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(1, "sync_recv", "__u32", "Sync transactions received while frozen")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ .constraints = "Bit 0: received after frozen, Bit 1: pending during freeze",
+ KAPI_PARAM_END
+
+ KAPI_PARAM(2, "async_recv", "__u32", "Async transactions received while frozen")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EINVAL, -EFAULT},
+ .error_count = 2,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EINVAL, "EINVAL", "Process not found",
+ "No binder process found with given PID")
+ KAPI_ERROR(1, -EFAULT, "EFAULT", "Failed to copy data",
+ "Invalid user pointer provided")
+
+ .error_count = 2,
+ .param_count = 3,
+ .since_version = "5.9",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_enable_oneway_spam_detection_spec = {
+ .cmd = BINDER_ENABLE_ONEWAY_SPAM_DETECTION,
+ .cmd_name = "BINDER_ENABLE_ONEWAY_SPAM_DETECTION",
+ .input_size = sizeof(__u32),
+ .output_size = 0,
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_enable_oneway_spam_detection",
+ KAPI_DESCRIPTION("Enable/disable oneway spam detection")
+ KAPI_LONG_DESC("Controls whether the driver monitors for excessive "
+ "oneway transactions that might indicate spam or abuse. "
+ "When enabled, BR_ONEWAY_SPAM_SUSPECT is sent when threshold exceeded.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "enable", "__u32", "1 to enable, 0 to disable")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
+ .type = KAPI_TYPE_UINT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = 0,
+ .max_value = 1,
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EFAULT},
+ .error_count = 1,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EFAULT, "EFAULT", "Failed to copy from user",
+ "Invalid user pointer provided")
+
+ .error_count = 1,
+ .param_count = 1,
+ .since_version = "5.13",
+ },
+};
+
+static const struct kapi_ioctl_spec binder_get_extended_error_spec = {
+ .cmd = BINDER_GET_EXTENDED_ERROR,
+ .cmd_name = "BINDER_GET_EXTENDED_ERROR",
+ .input_size = 0,
+ .output_size = sizeof(struct binder_extended_error),
+ .file_ops_name = "binder_fops",
+ .api_spec = {
+ .name = "binder_get_extended_error",
+ KAPI_DESCRIPTION("Get extended error information")
+ KAPI_LONG_DESC("Retrieves detailed error information from the last "
+ "failed binder operation on this thread. Clears the "
+ "error after reading.")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+ /* Parameters */
+ KAPI_PARAM(0, "id", "__u32", "Error identifier")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(1, "command", "__u32", "Binder command that failed")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_UINT,
+ KAPI_PARAM_END
+
+ KAPI_PARAM(2, "param", "__s32", "Error parameter (negative errno)")
+ KAPI_PARAM_FLAGS(KAPI_PARAM_OUT)
+ .type = KAPI_TYPE_INT,
+ .constraint_type = KAPI_CONSTRAINT_RANGE,
+ .min_value = -MAX_ERRNO,
+ .max_value = 0,
+ KAPI_PARAM_END
+
+ /* Return value */
+ KAPI_RETURN("int", "0 on success, negative errno on failure")
+ .type = KAPI_TYPE_INT,
+ .check_type = KAPI_RETURN_ERROR_CHECK,
+ .error_values = (const s64[]){-EFAULT},
+ .error_count = 1,
+ KAPI_RETURN_END
+
+ /* Errors */
+ KAPI_ERROR(0, -EFAULT, "EFAULT", "Failed to copy to user",
+ "Invalid user pointer provided")
+
+ .error_count = 1,
+ .param_count = 3,
+ .since_version = "5.16",
+ .notes = "Error is cleared after reading, subsequent calls return BR_OK",
+ },
+};
+
+/* Register all binder IOCTL specifications */
+KAPI_IOCTL_SPEC_DRIVER("binder", {
+ &binder_write_read_spec,
+ &binder_set_max_threads_spec,
+ &binder_set_context_mgr_spec,
+ &binder_set_context_mgr_ext_spec,
+ &binder_thread_exit_spec,
+ &binder_version_spec,
+ &binder_get_node_info_for_ref_spec,
+ &binder_get_node_debug_info_spec,
+ &binder_freeze_spec,
+ &binder_get_frozen_info_spec,
+ &binder_enable_oneway_spam_detection_spec,
+ &binder_get_extended_error_spec,
+})
+
DEFINE_SHOW_ATTRIBUTE(state);
DEFINE_SHOW_ATTRIBUTE(state_hashed);
DEFINE_SHOW_ATTRIBUTE(stats);
@@ -7050,6 +7798,13 @@ static int __init binder_init(void)
if (ret)
return ret;

+ /* Initialize the wrapped file_operations */
+ kapi_init_fops_binder_fops();
+
+ ret = kapi_ioctl_specs_init();
+ if (ret)
+ goto err_kapi_init;
+
atomic_set(&binder_transaction_log.cur, ~0U);
atomic_set(&binder_transaction_log_failed.cur, ~0U);

@@ -7102,6 +7857,9 @@ static int __init binder_init(void)

err_alloc_device_names_failed:
debugfs_remove_recursive(binder_debugfs_dir_entry_root);
+ kapi_ioctl_specs_exit();
+
+err_kapi_init:
binder_alloc_shrinker_exit();

return ret;
--
2.39.5