mirror of
https://github.com/libguestfs/libguestfs.git
synced 2026-03-21 22:53:37 +00:00
796ce74f31
Instead of generating the p2v kernel config using the OCaml generator, create a Perl script to do this job, mostly at build time. This is done to rely less on the generator for p2v, and because the generation of these sources is quick enough that it can be done at build time (instead of shipping the generated sources in dist tarballs). The generate-p2v-config.pl mimics what generator/p2v_config.ml -- namings, and general structure are kept close to that for comparison. The two C sources are created at build time by the script; however, the p2v-config.h header is generated at configure time: this is done because p2v-config.h is included by p2v.h (another header), which in turn is included by all the p2v C sources -- automake is not able to properly resolve the dependency, and thus it would not be generated properly.
This program generates a large amount of code and documentation for all the daemon actions. To add a new action there are only two files you need to change, 'actions_*.ml' to describe the interface, and daemon/<somefile>.c to write the implementation. After editing these files, build it (make -C generator) to regenerate all the output files. 'make' will rerun this automatically when necessary. IMPORTANT: This program should NOT print any warnings at compile time or run time. If it prints warnings, you should treat them as errors. OCaml tips: (1) In emacs, install tuareg-mode to display and format OCaml code correctly. 'vim' comes with a good OCaml editing mode by default. (2) Read the resources at http://ocaml.org/learn/ (3) A module called 'Foo' is defined in one or two files called 'foo.mli' and 'foo.ml' (NB: lowercase first letter). The *.mli file, if present, defines the public interface for the module. The *.ml file is the implementation. If the *.mli file is missing then everything is exported. Some notable files in this directory: actions_*.ml The libguestfs API. proc_nr.ml Procedure numbers associated with each API. structs.ml Structures returned by the API. c.ml Generate C API. <lang>.ml Generate bindings for <lang>. main.ml The main generator program. Note about long descriptions: When referring to another action, use the format C<guestfs_other> (ie. the full name of the C function). This will be replaced as appropriate in other language bindings. Apart from that, long descriptions are just perldoc paragraphs. Note about extending functions: In general you cannot change the name, number of required arguments or type of required arguments of a function, since this would break backwards compatibility. You may add another optional argument, *if* the function has >= 1 optional arguments already. Add it at the end of the list. You may add optional arguments to a function that doesn't have any. However you *must* set the once_had_no_optargs flag to true, so that the relevant backwards compatibility bindings can be added.