binder: Add default binder devices through binderfs when configured
Currently, since each binderfs instance needs its own
private binder devices, every time a binderfs instance is
mounted, all the default binder devices need to be created
via the BINDER_CTL_ADD IOCTL. This patch aims to
add a solution to automatically create the default binder
devices for each binderfs instance that gets mounted.
To achieve this goal, when 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>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Link: https://lore.kernel.org/r/20190808222727.132744-2-hridya@google.com
Link: https://lore.kernel.org/r/20190904110704.8606-2-christian.brauner@ubuntu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index d8307cc..55c5adb 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -186,8 +186,7 @@ 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 +466,9 @@ 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 +523,22 @@ 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, ",")) {
+ 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,