binder: Support multiple /dev instances

Add a new module parameter 'devices', that can be used to specify the names of the binder device nodes we want to populate in /dev. Each device node has its own context manager, and is therefore logically separated from all the other device nodes. The config option CONFIG_ANDROID_BINDER_DEVICES can be used to set the default value of the parameter. This approach was favored over using IPC namespaces, mostly because we require a single process to be a part of multiple binder contexts, which seemed harder to achieve with namespaces. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Martijn Coenen <maco@google.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Amit Pundir <amit.pundir@linaro.org> Cc: Serban Constantinescu <serban.constantinescu@arm.com> Cc: Dmitry Shmidt <dimitrysh@google.com> Cc: Rom Lemarchand <romlem@google.com> Cc: Android Kernel Team <kernel-team@android.com> Signed-off-by: Martijn Coenen <maco@google.com> [jstultz: minor checkpatch warning fix] Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

binder: Support multiple /dev instances
Add a new module parameter 'devices', that can be used to specify the names of the binder device nodes we want to populate in /dev. Each device node has its own context manager, and is therefore logically separated from all the other device nodes. The config option CONFIG_ANDROID_BINDER_DEVICES can be used to set the default value of the parameter. This approach was favored over using IPC namespaces, mostly because we require a single process to be a part of multiple binder contexts, which seemed harder to achieve with namespaces. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Martijn Coenen <maco@google.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Amit Pundir <amit.pundir@linaro.org> Cc: Serban Constantinescu <serban.constantinescu@arm.com> Cc: Dmitry Shmidt <dimitrysh@google.com> Cc: Rom Lemarchand <romlem@google.com> Cc: Android Kernel Team <kernel-team@android.com> Signed-off-by: Martijn Coenen <maco@google.com> [jstultz: minor checkpatch warning fix] Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Martijn Coenen · Greg Kroah-Hartman
1 parent 14db31814a
Showing 2 changed files with 84 additions and 11 deletions Side-by-side Diff
drivers/android/Kconfig
drivers/android/binder.c
@@ -19,6 +19,18 @@
 	  Android process, using Binder to identify, invoke and pass arguments
 	  between said processes.
  
+config ANDROID_BINDER_DEVICES
+	string "Android Binder devices"
+	depends on ANDROID_BINDER_IPC
+	default "binder"
+	---help---
+	  Default value for the binder.devices parameter.
+
+	  The binder.devices parameter is a comma-separated list of strings
+	  that specifies the names of the binder device nodes that will be
+	  created. Each binder device has its own context manager, and is
+	  therefore logically separated from the other devices.
+
 config ANDROID_BINDER_IPC_32BIT
 	bool
 	depends on !64BIT && ANDROID_BINDER_IPC
@@ -50,6 +50,7 @@
 static DEFINE_MUTEX(binder_deferred_lock);
 static DEFINE_MUTEX(binder_mmap_lock);
  
+static HLIST_HEAD(binder_devices);
 static HLIST_HEAD(binder_procs);
 static HLIST_HEAD(binder_deferred_list);
 static HLIST_HEAD(binder_dead_nodes);
@@ -113,6 +114,9 @@
 static bool binder_debug_no_lock;
 module_param_named(proc_no_lock, binder_debug_no_lock, bool, S_IWUSR | S_IRUGO);
  
+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;
  
@@ -220,9 +224,10 @@
 	const char *name;
 };
  
-static struct binder_context global_context = {
-	.binder_context_mgr_uid = INVALID_UID,
-	.name = "binder",
+struct binder_device {
+	struct hlist_node hlist;
+	struct miscdevice miscdev;
+	struct binder_context context;
 };
  
 struct binder_work {
@@ -3047,6 +3052,7 @@
 static int binder_open(struct inode *nodp, struct file *filp)
 {
 	struct binder_proc *proc;
+	struct binder_device *binder_dev;
  
 	binder_debug(BINDER_DEBUG_OPEN_CLOSE, "binder_open: %d:%d\n",
 		     current->group_leader->pid, current->pid);
  
@@ -3057,10 +3063,12 @@
 	get_task_struct(current);
 	proc->tsk = current;
 	proc->vma_vm_mm = current->mm;
-	proc->context = &global_context;
 	INIT_LIST_HEAD(&proc->todo);
 	init_waitqueue_head(&proc->wait);
 	proc->default_priority = task_nice(current);
+	binder_dev = container_of(filp->private_data, struct binder_device,
+				  miscdev);
+	proc->context = &binder_dev->context;
  
 	binder_lock(__func__);
  
  
  
  
@@ -3767,26 +3775,50 @@
 	.release = binder_release,
 };
  
-static struct miscdevice binder_miscdev = {
-	.minor = MISC_DYNAMIC_MINOR,
-	.name = "binder",
-	.fops = &binder_fops
-};
-
 BINDER_DEBUG_ENTRY(state);
 BINDER_DEBUG_ENTRY(stats);
 BINDER_DEBUG_ENTRY(transactions);
 BINDER_DEBUG_ENTRY(transaction_log);
  
+static int __init init_binder_device(const char *name)
+{
+	int ret;
+	struct binder_device *binder_device;
+
+	binder_device = kzalloc(sizeof(*binder_device), GFP_KERNEL);
+	if (!binder_device)
+		return -ENOMEM;
+
+	binder_device->miscdev.fops = &binder_fops;
+	binder_device->miscdev.minor = MISC_DYNAMIC_MINOR;
+	binder_device->miscdev.name = name;
+
+	binder_device->context.binder_context_mgr_uid = INVALID_UID;
+	binder_device->context.name = name;
+
+	ret = misc_register(&binder_device->miscdev);
+	if (ret < 0) {
+		kfree(binder_device);
+		return ret;
+	}
+
+	hlist_add_head(&binder_device->hlist, &binder_devices);
+
+	return ret;
+}
+
 static int __init binder_init(void)
 {
 	int ret;
+	char *device_name, *device_names;
+	struct binder_device *device;
+	struct hlist_node *tmp;
  
 	binder_debugfs_dir_entry_root = debugfs_create_dir("binder", NULL);
 	if (binder_debugfs_dir_entry_root)
 		binder_debugfs_dir_entry_proc = debugfs_create_dir("proc",
 						 binder_debugfs_dir_entry_root);
-	ret = misc_register(&binder_miscdev);
+
 	if (binder_debugfs_dir_entry_root) {
 		debugfs_create_file("state",
 				    S_IRUGO,
@@ -3814,6 +3846,35 @@
 				    &binder_transaction_log_failed,
 				    &binder_transaction_log_fops);
 	}
+
+	/*
+	 * Copy the module_parameter string, because we don't want to
+	 * tokenize it in-place.
+	 */
+	device_names = kzalloc(strlen(binder_devices_param) + 1, GFP_KERNEL);
+	if (!device_names) {
+		ret = -ENOMEM;
+		goto err_alloc_device_names_failed;
+	}
+	strcpy(device_names, binder_devices_param);
+
+	while ((device_name = strsep(&device_names, ","))) {
+		ret = init_binder_device(device_name);
+		if (ret)
+			goto err_init_binder_device_failed;
+	}
+
+	return ret;
+
+err_init_binder_device_failed:
+	hlist_for_each_entry_safe(device, tmp, &binder_devices, hlist) {
+		misc_deregister(&device->miscdev);
+		hlist_del(&device->hlist);
+		kfree(device);
+	}
+err_alloc_device_names_failed:
+	debugfs_remove_recursive(binder_debugfs_dir_entry_root);
+
 	return ret;
 }
...	...	@@ -19,6 +19,18 @@
19	19	Android process, using Binder to identify, invoke and pass arguments
20	20	between said processes.
21	21
	22	+config ANDROID_BINDER_DEVICES
	23	+ string "Android Binder devices"
	24	+ depends on ANDROID_BINDER_IPC
	25	+ default "binder"
	26	+ ---help---
	27	+ Default value for the binder.devices parameter.
	28	+
	29	+ The binder.devices parameter is a comma-separated list of strings
	30	+ that specifies the names of the binder device nodes that will be
	31	+ created. Each binder device has its own context manager, and is
	32	+ therefore logically separated from the other devices.
	33	+
22	34	config ANDROID_BINDER_IPC_32BIT
23	35	bool
24	36	depends on !64BIT && ANDROID_BINDER_IPC
...	...	@@ -50,6 +50,7 @@
50	50	static DEFINE_MUTEX(binder_deferred_lock);
51	51	static DEFINE_MUTEX(binder_mmap_lock);
52	52
	53	+static HLIST_HEAD(binder_devices);
53	54	static HLIST_HEAD(binder_procs);
54	55	static HLIST_HEAD(binder_deferred_list);
55	56	static HLIST_HEAD(binder_dead_nodes);
...	...	@@ -113,6 +114,9 @@
113	114	static bool binder_debug_no_lock;
114	115	module_param_named(proc_no_lock, binder_debug_no_lock, bool, S_IWUSR \| S_IRUGO);
115	116
	117	+static char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
	118	+module_param_named(devices, binder_devices_param, charp, 0444);
	119	+
116	120	static DECLARE_WAIT_QUEUE_HEAD(binder_user_error_wait);
117	121	static int binder_stop_on_user_error;
118	122
...	...	@@ -220,9 +224,10 @@
220	224	const char *name;
221	225	};
222	226
223		-static struct binder_context global_context = {
224		- .binder_context_mgr_uid = INVALID_UID,
225		- .name = "binder",
	227	+struct binder_device {
	228	+ struct hlist_node hlist;
	229	+ struct miscdevice miscdev;
	230	+ struct binder_context context;
226	231	};
227	232
228	233	struct binder_work {
...	...	@@ -3047,6 +3052,7 @@
3047	3052	static int binder_open(struct inode nodp, struct file filp)
3048	3053	{
3049	3054	struct binder_proc *proc;
	3055	+ struct binder_device *binder_dev;
3050	3056
3051	3057	binder_debug(BINDER_DEBUG_OPEN_CLOSE, "binder_open: %d:%d\n",
3052	3058	current->group_leader->pid, current->pid);
3053	3059
...	...	@@ -3057,10 +3063,12 @@
3057	3063	get_task_struct(current);
3058	3064	proc->tsk = current;
3059	3065	proc->vma_vm_mm = current->mm;
3060		- proc->context = &global_context;
3061	3066	INIT_LIST_HEAD(&proc->todo);
3062	3067	init_waitqueue_head(&proc->wait);
3063	3068	proc->default_priority = task_nice(current);
	3069	+ binder_dev = container_of(filp->private_data, struct binder_device,
	3070	+ miscdev);
	3071	+ proc->context = &binder_dev->context;
3064	3072
3065	3073	binder_lock(__func__);
3066	3074
3067	3075
3068	3076
3069	3077
...	...	@@ -3767,26 +3775,50 @@
3767	3775	.release = binder_release,
3768	3776	};
3769	3777
3770		-static struct miscdevice binder_miscdev = {
3771		- .minor = MISC_DYNAMIC_MINOR,
3772		- .name = "binder",
3773		- .fops = &binder_fops
3774		-};
3775		-
3776	3778	BINDER_DEBUG_ENTRY(state);
3777	3779	BINDER_DEBUG_ENTRY(stats);
3778	3780	BINDER_DEBUG_ENTRY(transactions);
3779	3781	BINDER_DEBUG_ENTRY(transaction_log);
3780	3782
	3783	+static int __init init_binder_device(const char *name)
	3784	+{
	3785	+ int ret;
	3786	+ struct binder_device *binder_device;
	3787	+
	3788	+ binder_device = kzalloc(sizeof(*binder_device), GFP_KERNEL);
	3789	+ if (!binder_device)
	3790	+ return -ENOMEM;
	3791	+
	3792	+ binder_device->miscdev.fops = &binder_fops;
	3793	+ binder_device->miscdev.minor = MISC_DYNAMIC_MINOR;
	3794	+ binder_device->miscdev.name = name;
	3795	+
	3796	+ binder_device->context.binder_context_mgr_uid = INVALID_UID;
	3797	+ binder_device->context.name = name;
	3798	+
	3799	+ ret = misc_register(&binder_device->miscdev);
	3800	+ if (ret < 0) {
	3801	+ kfree(binder_device);
	3802	+ return ret;
	3803	+ }
	3804	+
	3805	+ hlist_add_head(&binder_device->hlist, &binder_devices);
	3806	+
	3807	+ return ret;
	3808	+}
	3809	+
3781	3810	static int __init binder_init(void)
3782	3811	{
3783	3812	int ret;
	3813	+ char device_name, device_names;
	3814	+ struct binder_device *device;
	3815	+ struct hlist_node *tmp;
3784	3816
3785	3817	binder_debugfs_dir_entry_root = debugfs_create_dir("binder", NULL);
3786	3818	if (binder_debugfs_dir_entry_root)
3787	3819	binder_debugfs_dir_entry_proc = debugfs_create_dir("proc",
3788	3820	binder_debugfs_dir_entry_root);
3789		- ret = misc_register(&binder_miscdev);
	3821	+
3790	3822	if (binder_debugfs_dir_entry_root) {
3791	3823	debugfs_create_file("state",
3792	3824	S_IRUGO,
...	...	@@ -3814,6 +3846,35 @@
3814	3846	&binder_transaction_log_failed,
3815	3847	&binder_transaction_log_fops);
3816	3848	}
	3849	+
	3850	+ /*
	3851	+ * Copy the module_parameter string, because we don't want to
	3852	+ * tokenize it in-place.
	3853	+ */
	3854	+ device_names = kzalloc(strlen(binder_devices_param) + 1, GFP_KERNEL);
	3855	+ if (!device_names) {
	3856	+ ret = -ENOMEM;
	3857	+ goto err_alloc_device_names_failed;
	3858	+ }
	3859	+ strcpy(device_names, binder_devices_param);
	3860	+
	3861	+ while ((device_name = strsep(&device_names, ","))) {
	3862	+ ret = init_binder_device(device_name);
	3863	+ if (ret)
	3864	+ goto err_init_binder_device_failed;
	3865	+ }
	3866	+
	3867	+ return ret;
	3868	+
	3869	+err_init_binder_device_failed:
	3870	+ hlist_for_each_entry_safe(device, tmp, &binder_devices, hlist) {
	3871	+ misc_deregister(&device->miscdev);
	3872	+ hlist_del(&device->hlist);
	3873	+ kfree(device);
	3874	+ }
	3875	+err_alloc_device_names_failed:
	3876	+ debugfs_remove_recursive(binder_debugfs_dir_entry_root);
	3877	+
3817	3878	return ret;
3818	3879	}
3819	3880