[PATCH] Add default binder devices through binderfs when configured

[PATCH] Add default binder devices through binderfs when configured

[Hridya Valsaraju]

If CONFIG_ANDROID_BINDERFS is set, the default binder devices
specified by CONFIG_ANDROID_BINDER_DEVICES are created in each
binderfs instance instead of global devices being created by
the binder driver.

Co-developed-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Hridya Valsaraju <hridya@google.com>
---
 drivers/android/binder.c   |  3 ++-
 drivers/android/binderfs.c | 46 ++++++++++++++++++++++++++++++++++----
 2 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 466b6a7f8ab7..65a99ac26711 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -6279,7 +6279,8 @@ static int __init binder_init(void)
 				    &transaction_log_fops);
 	}
 
-	if (strcmp(binder_devices_param, "") != 0) {
+	if (!IS_ENABLED(CONFIG_ANDROID_BINDERFS) &&
+	    strcmp(binder_devices_param, "") != 0) {
 		/*
 		* Copy the module_parameter string, because we don't want to
 		* tokenize it in-place.
diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index e773f45d19d9..9f5ed50ffd70 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -48,6 +48,10 @@ static dev_t binderfs_dev;
 static DEFINE_MUTEX(binderfs_minors_mutex);
 static DEFINE_IDA(binderfs_minors);
 
+static char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
+module_param_named(devices, binder_devices_param, charp, 0444);
+MODULE_PARM_DESC(devices, "Binder devices to be created by default");
+
 /**
  * binderfs_mount_opts - mount options for binderfs
  * @max: maximum number of allocatable binderfs binder devices
@@ -135,7 +139,6 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
 #else
 	bool use_reserve = true;
 #endif
-
 	/* Reserve new minor number for the new device. */
 	mutex_lock(&binderfs_minors_mutex);
 	if (++info->device_count <= info->mount_opts.max)
@@ -186,8 +189,7 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
 	req->major = MAJOR(binderfs_dev);
 	req->minor = minor;
 
-	ret = copy_to_user(userp, req, sizeof(*req));
-	if (ret) {
+	if (userp && copy_to_user(userp, req, sizeof(*req))) {
 		ret = -EFAULT;
 		goto err;
 	}
@@ -467,6 +469,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
 	int ret;
 	struct binderfs_info *info;
 	struct inode *inode = NULL;
+	struct binderfs_device device_info = { 0 };
+	const char *name;
+	size_t len;
 
 	sb->s_blocksize = PAGE_SIZE;
 	sb->s_blocksize_bits = PAGE_SHIFT;
@@ -521,7 +526,28 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
 	if (!sb->s_root)
 		return -ENOMEM;
 
-	return binderfs_binder_ctl_create(sb);
+	ret = binderfs_binder_ctl_create(sb);
+	if (ret)
+		return ret;
+
+	name = binder_devices_param;
+	for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
+		/*
+		 * init_binderfs() has already checked that the length of
+		 * device_name_entry->name is not greater than device_info.name.
+		 */
+		strscpy(device_info.name, name, len + 1);
+		ret = binderfs_binder_device_create(inode, NULL, &device_info);
+		if (ret)
+			return ret;
+		name += len;
+		if (*name == ',')
+			name++;
+
+	}
+
+	return 0;
+
 }
 
 static struct dentry *binderfs_mount(struct file_system_type *fs_type,
@@ -553,6 +579,18 @@ static struct file_system_type binder_fs_type = {
 int __init init_binderfs(void)
 {
 	int ret;
+	const char *name;
+	size_t len;
+
+	/* Verify that the default binderfs device names are valid. */
+	name = binder_devices_param;
+	for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
+		if (len > BINDERFS_MAX_NAME)
+			return -E2BIG;
+		name += len;
+		if (*name == ',')
+			name++;
+	}
 
 	/* Allocate new major number for binderfs. */
 	ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR,
-- 
2.22.0.770.g0f2c4a37fd-goog

Re: [PATCH] Add default binder devices through binderfs when configured

[Greg Kroah-Hartman]

On Thu, Aug 01, 2019 at 03:35:56PM -0700, Hridya Valsaraju wrote:
> If CONFIG_ANDROID_BINDERFS is set, the default binder devices
> specified by CONFIG_ANDROID_BINDER_DEVICES are created in each
> binderfs instance instead of global devices being created by
> the binder driver.
> 
> Co-developed-by: Christian Brauner <christian.brauner@ubuntu.com>
> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
> Signed-off-by: Hridya Valsaraju <hridya@google.com>
> ---
>  drivers/android/binder.c   |  3 ++-
>  drivers/android/binderfs.c | 46 ++++++++++++++++++++++++++++++++++----
>  2 files changed, 44 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 466b6a7f8ab7..65a99ac26711 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -6279,7 +6279,8 @@ static int __init binder_init(void)
>  				    &transaction_log_fops);
>  	}
>  
> -	if (strcmp(binder_devices_param, "") != 0) {
> +	if (!IS_ENABLED(CONFIG_ANDROID_BINDERFS) &&
> +	    strcmp(binder_devices_param, "") != 0) {
>  		/*
>  		* Copy the module_parameter string, because we don't want to
>  		* tokenize it in-place.
> diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
> index e773f45d19d9..9f5ed50ffd70 100644
> --- a/drivers/android/binderfs.c
> +++ b/drivers/android/binderfs.c
> @@ -48,6 +48,10 @@ static dev_t binderfs_dev;
>  static DEFINE_MUTEX(binderfs_minors_mutex);
>  static DEFINE_IDA(binderfs_minors);
>  
> +static char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
> +module_param_named(devices, binder_devices_param, charp, 0444);
> +MODULE_PARM_DESC(devices, "Binder devices to be created by default");
> +

Why are you creating a module parameter?  That was not in your changelog
:(



>  /**
>   * binderfs_mount_opts - mount options for binderfs
>   * @max: maximum number of allocatable binderfs binder devices
> @@ -135,7 +139,6 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
>  #else
>  	bool use_reserve = true;
>  #endif
> -
>  	/* Reserve new minor number for the new device. */
>  	mutex_lock(&binderfs_minors_mutex);
>  	if (++info->device_count <= info->mount_opts.max)
> @@ -186,8 +189,7 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
>  	req->major = MAJOR(binderfs_dev);
>  	req->minor = minor;
>  
> -	ret = copy_to_user(userp, req, sizeof(*req));
> -	if (ret) {
> +	if (userp && copy_to_user(userp, req, sizeof(*req))) {
>  		ret = -EFAULT;
>  		goto err;
>  	}
> @@ -467,6 +469,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
>  	int ret;
>  	struct binderfs_info *info;
>  	struct inode *inode = NULL;
> +	struct binderfs_device device_info = { 0 };
> +	const char *name;
> +	size_t len;
>  
>  	sb->s_blocksize = PAGE_SIZE;
>  	sb->s_blocksize_bits = PAGE_SHIFT;
> @@ -521,7 +526,28 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
>  	if (!sb->s_root)
>  		return -ENOMEM;
>  
> -	return binderfs_binder_ctl_create(sb);
> +	ret = binderfs_binder_ctl_create(sb);
> +	if (ret)
> +		return ret;
> +
> +	name = binder_devices_param;
> +	for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> +		/*
> +		 * init_binderfs() has already checked that the length of
> +		 * device_name_entry->name is not greater than device_info.name.
> +		 */
> +		strscpy(device_info.name, name, len + 1);
> +		ret = binderfs_binder_device_create(inode, NULL, &device_info);
> +		if (ret)
> +			return ret;
> +		name += len;
> +		if (*name == ',')
> +			name++;
> +
> +	}
> +
> +	return 0;
> +
>  }
>  
>  static struct dentry *binderfs_mount(struct file_system_type *fs_type,
> @@ -553,6 +579,18 @@ static struct file_system_type binder_fs_type = {
>  int __init init_binderfs(void)
>  {
>  	int ret;
> +	const char *name;
> +	size_t len;
> +
> +	/* Verify that the default binderfs device names are valid. */
> +	name = binder_devices_param;
> +	for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> +		if (len > BINDERFS_MAX_NAME)
> +			return -E2BIG;
> +		name += len;
> +		if (*name == ',')
> +			name++;
> +	}

This verification should be a separate patch, right?

But the real issue here is I have no idea _why_ you are wanting this
patch.  The changelog text says _what_ you are doing only, which isn't
ok.

Please provide more information as to why this is needed, what problem
it is solving, and break this up into a patch series and resend.

thanks,

greg k-h

Re: [PATCH] Add default binder devices through binderfs when configured

[Christian Brauner]

On Fri, Aug 02, 2019 at 08:18:38AM +0200, Greg Kroah-Hartman wrote:
> On Thu, Aug 01, 2019 at 03:35:56PM -0700, Hridya Valsaraju wrote:
> > If CONFIG_ANDROID_BINDERFS is set, the default binder devices
> > specified by CONFIG_ANDROID_BINDER_DEVICES are created in each
> > binderfs instance instead of global devices being created by
> > the binder driver.
> > 
> > Co-developed-by: Christian Brauner <christian.brauner@ubuntu.com>
> > Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
> > Signed-off-by: Hridya Valsaraju <hridya@google.com>
> > ---
> >  drivers/android/binder.c   |  3 ++-
> >  drivers/android/binderfs.c | 46 ++++++++++++++++++++++++++++++++++----
> >  2 files changed, 44 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> > index 466b6a7f8ab7..65a99ac26711 100644
> > --- a/drivers/android/binder.c
> > +++ b/drivers/android/binder.c
> > @@ -6279,7 +6279,8 @@ static int __init binder_init(void)
> >  				    &transaction_log_fops);
> >  	}
> >  
> > -	if (strcmp(binder_devices_param, "") != 0) {
> > +	if (!IS_ENABLED(CONFIG_ANDROID_BINDERFS) &&
> > +	    strcmp(binder_devices_param, "") != 0) {
> >  		/*
> >  		* Copy the module_parameter string, because we don't want to
> >  		* tokenize it in-place.
> > diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
> > index e773f45d19d9..9f5ed50ffd70 100644
> > --- a/drivers/android/binderfs.c
> > +++ b/drivers/android/binderfs.c
> > @@ -48,6 +48,10 @@ static dev_t binderfs_dev;
> >  static DEFINE_MUTEX(binderfs_minors_mutex);
> >  static DEFINE_IDA(binderfs_minors);
> >  
> > +static char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
> > +module_param_named(devices, binder_devices_param, charp, 0444);
> > +MODULE_PARM_DESC(devices, "Binder devices to be created by default");
> > +
> 
> Why are you creating a module parameter?  That was not in your changelog
> :(

Yeah, you don't need an additional module parameter. You can just move

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

from binder.c to binder_internal.h and expose it to binder.c and
binderfs.c this way. This will work just fine since binderfs.c doesn't
modify the parameter and binder.c makes a copy of it before doing so.

> 
> 
> 
> >  /**
> >   * binderfs_mount_opts - mount options for binderfs
> >   * @max: maximum number of allocatable binderfs binder devices
> > @@ -135,7 +139,6 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
> >  #else
> >  	bool use_reserve = true;
> >  #endif
> > -
> >  	/* Reserve new minor number for the new device. */
> >  	mutex_lock(&binderfs_minors_mutex);
> >  	if (++info->device_count <= info->mount_opts.max)
> > @@ -186,8 +189,7 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
> >  	req->major = MAJOR(binderfs_dev);
> >  	req->minor = minor;
> >  
> > -	ret = copy_to_user(userp, req, sizeof(*req));
> > -	if (ret) {
> > +	if (userp && copy_to_user(userp, req, sizeof(*req))) {
> >  		ret = -EFAULT;
> >  		goto err;
> >  	}
> > @@ -467,6 +469,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> >  	int ret;
> >  	struct binderfs_info *info;
> >  	struct inode *inode = NULL;
> > +	struct binderfs_device device_info = { 0 };
> > +	const char *name;
> > +	size_t len;
> >  
> >  	sb->s_blocksize = PAGE_SIZE;
> >  	sb->s_blocksize_bits = PAGE_SHIFT;
> > @@ -521,7 +526,28 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> >  	if (!sb->s_root)
> >  		return -ENOMEM;
> >  
> > -	return binderfs_binder_ctl_create(sb);
> > +	ret = binderfs_binder_ctl_create(sb);
> > +	if (ret)
> > +		return ret;
> > +
> > +	name = binder_devices_param;
> > +	for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> > +		/*
> > +		 * init_binderfs() has already checked that the length of
> > +		 * device_name_entry->name is not greater than device_info.name.
> > +		 */
> > +		strscpy(device_info.name, name, len + 1);
> > +		ret = binderfs_binder_device_create(inode, NULL, &device_info);
> > +		if (ret)
> > +			return ret;
> > +		name += len;
> > +		if (*name == ',')
> > +			name++;
> > +
> > +	}
> > +
> > +	return 0;
> > +
> >  }
> >  
> >  static struct dentry *binderfs_mount(struct file_system_type *fs_type,
> > @@ -553,6 +579,18 @@ static struct file_system_type binder_fs_type = {
> >  int __init init_binderfs(void)
> >  {
> >  	int ret;
> > +	const char *name;
> > +	size_t len;
> > +
> > +	/* Verify that the default binderfs device names are valid. */
> > +	name = binder_devices_param;
> > +	for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> > +		if (len > BINDERFS_MAX_NAME)
> > +			return -E2BIG;
> > +		name += len;
> > +		if (*name == ',')
> > +			name++;
> > +	}
> 
> This verification should be a separate patch, right?
> 
> But the real issue here is I have no idea _why_ you are wanting this
> patch.  The changelog text says _what_ you are doing only, which isn't
> ok.
> 
> Please provide more information as to why this is needed, what problem
> it is solving, and break this up into a patch series and resend.
> 
> thanks,
> 
> greg k-h

Re: [PATCH] Add default binder devices through binderfs when configured

[Hridya Valsaraju]

On Fri, Aug 2, 2019 at 8:06 AM Christian Brauner <christian@brauner.io> wrote:
>
> On Fri, Aug 02, 2019 at 08:18:38AM +0200, Greg Kroah-Hartman wrote:
> > On Thu, Aug 01, 2019 at 03:35:56PM -0700, Hridya Valsaraju wrote:
> > > If CONFIG_ANDROID_BINDERFS is set, the default binder devices
> > > specified by CONFIG_ANDROID_BINDER_DEVICES are created in each
> > > binderfs instance instead of global devices being created by
> > > the binder driver.
> > >
> > > Co-developed-by: Christian Brauner <christian.brauner@ubuntu.com>
> > > Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
> > > Signed-off-by: Hridya Valsaraju <hridya@google.com>
> > > ---
> > >  drivers/android/binder.c   |  3 ++-
> > >  drivers/android/binderfs.c | 46 ++++++++++++++++++++++++++++++++++----
> > >  2 files changed, 44 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> > > index 466b6a7f8ab7..65a99ac26711 100644
> > > --- a/drivers/android/binder.c
> > > +++ b/drivers/android/binder.c
> > > @@ -6279,7 +6279,8 @@ static int __init binder_init(void)
> > >                                 &transaction_log_fops);
> > >     }
> > >
> > > -   if (strcmp(binder_devices_param, "") != 0) {
> > > +   if (!IS_ENABLED(CONFIG_ANDROID_BINDERFS) &&
> > > +       strcmp(binder_devices_param, "") != 0) {
> > >             /*
> > >             * Copy the module_parameter string, because we don't want to
> > >             * tokenize it in-place.
> > > diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
> > > index e773f45d19d9..9f5ed50ffd70 100644
> > > --- a/drivers/android/binderfs.c
> > > +++ b/drivers/android/binderfs.c
> > > @@ -48,6 +48,10 @@ static dev_t binderfs_dev;
> > >  static DEFINE_MUTEX(binderfs_minors_mutex);
> > >  static DEFINE_IDA(binderfs_minors);
> > >
> > > +static char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
> > > +module_param_named(devices, binder_devices_param, charp, 0444);
> > > +MODULE_PARM_DESC(devices, "Binder devices to be created by default");
> > > +
> >
> > Why are you creating a module parameter?  That was not in your changelog
> > :(
>
> Yeah, you don't need an additional module parameter. You can just move
>
> static char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
> module_param_named(devices, binder_devices_param, charp, 0444);
>
> from binder.c to binder_internal.h and expose it to binder.c and
> binderfs.c this way. This will work just fine since binderfs.c doesn't
> modify the parameter and binder.c makes a copy of it before doing so.
>
> >
> >
> >
> > >  /**
> > >   * binderfs_mount_opts - mount options for binderfs
> > >   * @max: maximum number of allocatable binderfs binder devices
> > > @@ -135,7 +139,6 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
> > >  #else
> > >     bool use_reserve = true;
> > >  #endif
> > > -
> > >     /* Reserve new minor number for the new device. */
> > >     mutex_lock(&binderfs_minors_mutex);
> > >     if (++info->device_count <= info->mount_opts.max)
> > > @@ -186,8 +189,7 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
> > >     req->major = MAJOR(binderfs_dev);
> > >     req->minor = minor;
> > >
> > > -   ret = copy_to_user(userp, req, sizeof(*req));
> > > -   if (ret) {
> > > +   if (userp && copy_to_user(userp, req, sizeof(*req))) {
> > >             ret = -EFAULT;
> > >             goto err;
> > >     }
> > > @@ -467,6 +469,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> > >     int ret;
> > >     struct binderfs_info *info;
> > >     struct inode *inode = NULL;
> > > +   struct binderfs_device device_info = { 0 };
> > > +   const char *name;
> > > +   size_t len;
> > >
> > >     sb->s_blocksize = PAGE_SIZE;
> > >     sb->s_blocksize_bits = PAGE_SHIFT;
> > > @@ -521,7 +526,28 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> > >     if (!sb->s_root)
> > >             return -ENOMEM;
> > >
> > > -   return binderfs_binder_ctl_create(sb);
> > > +   ret = binderfs_binder_ctl_create(sb);
> > > +   if (ret)
> > > +           return ret;
> > > +
> > > +   name = binder_devices_param;
> > > +   for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> > > +           /*
> > > +            * init_binderfs() has already checked that the length of
> > > +            * device_name_entry->name is not greater than device_info.name.
> > > +            */
> > > +           strscpy(device_info.name, name, len + 1);
> > > +           ret = binderfs_binder_device_create(inode, NULL, &device_info);
> > > +           if (ret)
> > > +                   return ret;
> > > +           name += len;
> > > +           if (*name == ',')
> > > +                   name++;
> > > +
> > > +   }
> > > +
> > > +   return 0;
> > > +
> > >  }
> > >
> > >  static struct dentry *binderfs_mount(struct file_system_type *fs_type,
> > > @@ -553,6 +579,18 @@ static struct file_system_type binder_fs_type = {
> > >  int __init init_binderfs(void)
> > >  {
> > >     int ret;
> > > +   const char *name;
> > > +   size_t len;
> > > +
> > > +   /* Verify that the default binderfs device names are valid. */
> > > +   name = binder_devices_param;
> > > +   for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> > > +           if (len > BINDERFS_MAX_NAME)
> > > +                   return -E2BIG;
> > > +           name += len;
> > > +           if (*name == ',')
> > > +                   name++;
> > > +   }
> >
> > This verification should be a separate patch, right?
> >
> > But the real issue here is I have no idea _why_ you are wanting this
> > patch.  The changelog text says _what_ you are doing only, which isn't
> > ok.
> >
> > Please provide more information as to why this is needed, what problem
> > it is solving, and break this up into a patch series and resend.

Thank you Greg and Christian, I will address all issues in v2 and resend.

> >
> > thanks,
> >
> > greg k-h
>
> --
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>