1Android kernel headers
2======================
3
4This project contains the original kernel headers that are used to generate
5Bionic's "cleaned-up" user-land headers.
6
7They are mostly covered by the GPLv2 + exception, and thus cannot be
8distributed as part of the platform itself.  The cleaned up headers do not
9contain copyrightable information and are distributed with bionic.
10
11Importing modified kernel headers files is done using scripts found in bionic.
12
13Note that if you're actually just trying to expose device-specific headers
14to build your device drivers, you shouldn't modify bionic. Instead
15use `TARGET_DEVICE_KERNEL_HEADERS` and friends described in
16[config.mk](https://android.googlesource.com/platform/build/+/master/core/config.mk#186).
17
18Regenerating the bionic headers
19-------------------------------
20The uapi directory contains the original kernel UAPI (userspace API) headers
21that are used to generate Bionic's "cleaned-up" user-land headers. The script
22`bionic/libc/kernel/tools/generate_uapi_headers.sh` automatically imports the
23headers from an android kernel repository.
24
25Running the script:
26```
27generate_uapi_headers.sh --download-kernel
28```
29
30In order to run the script, you must have properly initialized the build
31environment using the lunch command. The script will automatically retrieve
32an android kernel, generate all include files, and then copy the headers to
33this directory.
34
35Manually modified headers
36-------------------------
37The `modified/scsi` directory contains a set of manually updated headers.
38The scsi kernel headers were never properly made to into uapi versions,
39so this directory contains the unmodified scsi headers that are imported
40into bionic. The generation script will indicate if these files have
41changed and require another manual update.
42
43The files from the scsi directory will be copied into bionic after
44being processed as is, unless there exists a file of the same name in
45`../modified/scsi`. Any files found in the modified directory completely
46replace the ones in the scsi directory.
47