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| author | Christian Mauderer <Christian.Mauderer@embedded-brains.de> | 2016-07-06 16:06:54 +0200 |
|---|---|---|
| committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2016-08-03 14:13:19 +0200 |
| commit | c3a8e6bb86efa492f6fdc513ec4e7f7f31ff26f3 (patch) | |
| tree | 8631599fe1272e198d88b46e86fe90cb3dc7bd46 | |
| parent | testsuite/pf01: Test pfctl and pf. (diff) | |
| download | rtems-libbsd-c3a8e6bb86efa492f6fdc513ec4e7f7f31ff26f3.tar.bz2 | |
libbsd.txt: Add guide for user space tools.
| -rw-r--r-- | libbsd.txt | 30 |
1 files changed, 30 insertions, 0 deletions
@@ -579,6 +579,36 @@ Generating into /home/joel/newbsd/git/libbsd-8.2 The script may also be used to generate a diff in either forward or reverse direction. +== Porting of user space utilities + +The theory behind the described method is to put all BSS and initialized data +objects into a named section. This section then will be saved before the code is +executed and restored after it has finished. This method limits to a single +threaded execution of the application but minimizes the necessary changes to the +original FreeBSD code. + +. Import and commit the unchanged source files like described above. +. Add the files to the libbsd.py and build them. +. Use nm on the generated object files to find out which objects are initialized + (either in BSS -- type b or B -- or in the initialized data segment -- type d + or D). An example call could look like follows: + `arm-rtems4.12-nm build/arm-rtems4.12-xilinx_zynq_a9_qemu/freebsd/contrib/pf/pfctl/pfctl.c.10.o | grep ' [DdbB] '` +. Check the sources for everything that can be made const. This type of patches + should go back to the upstream FreeBSD sources. +. Check the sources for every global variable that can be made static. This type + of patches should go back to the upstream FreeBSD sources. +. Move static variables out of functions. This patches should also go upstream. +. Create one `xxx-data.h` file per c module. This header should contain + declarations for the remaining initialized objects matching the original + declarations but adding a section attribute. The section name has to match the + name of the RTEMS_LINKER_RWSET defined further below. For an example look at + `freebsd/contrib/pf/pfctl/pfctl-data.h`. +. Include the header files at the end of the corresponding c files. +. Add a rtems_bsd_command_xxx wrapper function to the c file containing the main + function. For an example look at `rtems_bsd_command_pfctl(...)` in + `freebsd/contrib/pf/pfctl/pfctl.c`. +. Create one compilable commit. + == Initialization of the BSD Library The initialization of the BSD library is based on the FreeBSD SYSINIT(9) |