On Thu, May 21, 2026 at 04:18:27PM +0200, Tomas Glozar wrote: > [ CC to linux-perf-users for the libsubcmd code changes ] > > rtla currently uses its own implementation that uses getopt_long() to > parse command-line arguments. > > Migrate rtla to use libsubcmd for command line argument parsing, > similarly to what is already done by other tools like perf, bpftool, > and objtool. Among other benefits, this allows help messages to be > generated automatically rather than having to be typed out manually > for each tool. > > libsubcmd is extended with a flag to parse optarg from separate > argument if a new flag is turned on. Without the flag, the old behavior > is preserved. That keeps the parsing working for tools that use > positional arguments, and allows RTLA to keep its flexible syntax for -C > and -t options and their long variants, --cgroup and --trace-output. > Another flag is added to disable automatic definition of --no-xy for > every option --xy and vice versa, which overlaps for RTLA's --irq and > --thread options. > > The new implementation is moved into a separate file, cli.c, together > with a tiny header counterpart, cli.h. This helps separate the parsing > logic, which has little in common with the rest of RTLA, in a separate > module. Another new file, cli_p.h, is used as a private header to contain > macros and static function declarations that are also used by unit tests > next to cli.c, but should not be imported from elsewhere. > > Macros to generate struct option array fields for libsubcmd's > parse_args() are used to preserve the consolidation of argument parsing > code across different RTLA tools. Kernel and user threads are, as > an exception, treated as common, although they are currently implemented > for timerlat only, in line with earlier consolidation changes. > > The test suite is expanded to include two levels of unit tests, one testing > the already existing tool_parse_args() functions, one tests option callbacks, > which are a new level of the CLI parser added in this patchset. This helps > to verify that no regressions are caused by this refactoring. > > I expect more improvements to the code being possible in the future, > like creating macros for option groups to further deduplicate the code, > reducing the amount of extra code in the _parse_args() functions, or > implementing support for unsetting options (which is currently only > supported for those that do not use a custom callback). > > v2 changes: > - Two unit test suites are added to cover regressions, after several > options were broken by the v1. The test suites cover all parsing > issues reported in the v1 as well as those found during additional > testing. > - Return value of all paths that print help, including those that > are handled in RTLA, are set to libsubcmd's help exit code of 129. > Previously, only the tool help returned 129. While some other tools > (e.g. bpftool) do that, RTLA unifies those for consistency. The return > value is also added to the corresponding section in documentation. > - Incorrect parsing of --no-irq and --no-thread is fixed using a newly > added libsubcmd option flag. > - Incorrect parsing of -n and -u timerlat options (which erroneously > required an argument in v1) is fixed. > - A now stale declaration of removed function common_parse_options() > is removed from common.h. > - Segmentation fault on abbreviated --help (e.g. --he) is fixed. > - Incorrect formatting of OPT_END macro (spurious tab) is fixed. > - All opt_* callbacks now reject unimplemented unset (--no-) correctly. > - opt_trigger_cb() and opt_filter_cb() now take only the required events > field, not the whole params structure. > - Spurious opt_osnoise_threshold_cb() which is actually just a wrapper for > opt_llong_callback() is removed. > - Old off-by-one typo is fixed in --dma-latency and -E/--entries error > messages, to make it consistent with the newly added unit tests. > - Fix a bug in Makefile that defined LIBSUBCMD_INCLUDES as -I... and then > used it as a target name: define it as the path only, and then add -I$(...) > to CFLAGS, as this is the only include path that is generated during the build > itself. > > v1: > https://lore.kernel.org/linux-trace-kernel/[email protected]/T > > Tomas Glozar (6): > rtla: Add libsubcmd dependency > tools subcmd: support optarg as separate argument > tools subcmd: allow parsing distinct --opt and --no-opt > rtla: Parse cmdline using libsubcmd > rtla/tests: Add unit tests for _parse_args() functions > rtla/tests: Add unit tests for CLI option callbacks
Reviewed-by: Wander Lairson Costa <[email protected]>
