From def95c73567dfacb22900cd0c4f01caff39e4c9e Mon Sep 17 00:00:00 2001 From: Martijn Coenen Date: Fri, 3 Feb 2017 14:40:52 -0800 Subject: binder: Add support for file-descriptor arrays This patch introduces a new binder_fd_array object, that allows us to support one or more file descriptors embedded in a buffer that is scatter-gathered. Cc: Greg Kroah-Hartman Cc: Martijn Coenen Cc: Arve Hjønnevåg Cc: Amit Pundir Cc: Serban Constantinescu Cc: Dmitry Shmidt Cc: Rom Lemarchand Cc: Android Kernel Team Signed-off-by: Martijn Coenen Signed-off-by: John Stultz Signed-off-by: Greg Kroah-Hartman --- include/uapi/linux/android/binder.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include/uapi/linux/android') diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h index f3ef6e2634ba..51f891fb1b18 100644 --- a/include/uapi/linux/android/binder.h +++ b/include/uapi/linux/android/binder.h @@ -33,6 +33,7 @@ enum { BINDER_TYPE_HANDLE = B_PACK_CHARS('s', 'h', '*', B_TYPE_LARGE), BINDER_TYPE_WEAK_HANDLE = B_PACK_CHARS('w', 'h', '*', B_TYPE_LARGE), BINDER_TYPE_FD = B_PACK_CHARS('f', 'd', '*', B_TYPE_LARGE), + BINDER_TYPE_FDA = B_PACK_CHARS('f', 'd', 'a', B_TYPE_LARGE), BINDER_TYPE_PTR = B_PACK_CHARS('p', 't', '*', B_TYPE_LARGE), }; @@ -129,6 +130,33 @@ enum { BINDER_BUFFER_FLAG_HAS_PARENT = 0x01, }; +/* struct binder_fd_array_object - object describing an array of fds in a buffer + * @hdr: common header structure + * @num_fds: number of file descriptors in the buffer + * @parent: index in offset array to buffer holding the fd array + * @parent_offset: start offset of fd array in the buffer + * + * A binder_fd_array object represents an array of file + * descriptors embedded in a binder_buffer_object. It is + * different from a regular binder_buffer_object because it + * describes a list of file descriptors to fix up, not an opaque + * blob of memory, and hence the kernel needs to treat it differently. + * + * An example of how this would be used is with Android's + * native_handle_t object, which is a struct with a list of integers + * and a list of file descriptors. The native_handle_t struct itself + * will be represented by a struct binder_buffer_objct, whereas the + * embedded list of file descriptors is represented by a + * struct binder_fd_array_object with that binder_buffer_object as + * a parent. + */ +struct binder_fd_array_object { + struct binder_object_header hdr; + binder_size_t num_fds; + binder_size_t parent; + binder_size_t parent_offset; +}; + /* * On 64-bit platforms where user code may run in 32-bits the driver must * translate the buffer (and local binder) addresses appropriately. -- cgit v1.2.3-55-g7522