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 <[email protected]> Signed-off-by: Christian Brauner <[email protected]> Signed-off-by: Hridya Valsaraju <[email protected]> --- 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
