kernel/linux.git/tools/tracing/rtla/src/utils.h, branch v7.2-rc1

rtla: Parse cmdline using libsubcmd

2026-05-28T11:02:48+00:00

Instead of using getopt_long() directly to parse the command line arguments given to an RTLA tool, use libsubcmd's parse_options(). Utilizing libsubcmd for parsing command line arguments has several benefits: - A help message is automatically generated by libsubcmd from the specification, removing the need of writing it by hand. - Options are sorted into groups based on which part of tracing (CPU, thread, auto-analysis, tuning, histogram) they relate to. - Common parsing patterns for numerical and boolean values now share code, with the target variable being stored in the option array. To avoid duplication of the option parsing logic, RTLA-specific macros defining struct option values are created: - RTLA_OPT_* for options common to all tools - OSNOISE_OPT_* and TIMERLAT_OPT_* for options specific to osnoise/timerlat tools - HIST_OPT_* macros for options specific to histogram-based tools. Individual *_parse_args() functions then construct an array out of these macros that is then passed to libsubcmd's parse_options(). All code specific to command line options parsing is moved out of the individual tool files into a new file, cli.c, which also contains the contents of the rtla.c file. A private header, cli_p.h, is added alongside the public header cli.h, so that unit tests are able to test statically declared option callbacks. Minor changes: - The return value of tool-level help option changes to 129, as this is the value set by libsubcmd; this is reflected in affected test cases. The implementation of help for command-level and tracer-level help is set to 129 as well for consistency, and the change is reflected in exit value documentation. - Related to the above, {rtla,osnoise,timerlat}_usage() are marked __noreturn and exit() is removed from after they are called for cleaner code. - The error messages for invalid argument for options --dma-latency and -E/--entries were corrected, fixing off-by-one in the limits. Note that unsetting options (using --no- syntax) is currently not implemented for options that use custom callbacks. For --irq and --thread, it will never be implemented, as they conflict with already existing --no-irq and --no-thread with a different meaning. Assisted-by: Composer:composer-1.5 Link: https://lore.kernel.org/r/20260528103254.2990068-5-tglozar@redhat.com Signed-off-by: Tomas Glozar

rtla: Add libsubcmd dependency

2026-05-28T11:02:47+00:00

In preparation for migrating RTLA to libsubcmd, build libsubcmd from the appropriate directory next to the RTLA build proper, and link the resulting object to RTLA. libsubcmd uses str_error_r() and strlcpy() at several places. To support these, also link the respective libraries from tools/lib. For completeness, also add tools/include to include path. This will allow other userspace functions and macros shipped with the kernel to be used in RTLA; perf and bpftool, two other users of libsubcmd, already do that. To prevent a name conflict, rename RTLA's run_command() function to run_tool_command(), and replace RTLA's own container_of implementation with the one in tools/include/linux/container_of.h. Assisted-by: Composer:composer-1 Link: https://lore.kernel.org/r/20260528103254.2990068-2-tglozar@redhat.com Signed-off-by: Tomas Glozar

rtla: Add str_has_prefix() helper function

2026-03-11T14:29:50+00:00

Add a str_has_prefix() helper function that tests whether a string starts with a given prefix. This function provides a cleaner interface for prefix matching compared to using strncmp() with strlen() directly. The function returns a boolean value indicating whether the string starts with the specified prefix. This helper will be used in subsequent changes to simplify prefix matching code throughout rtla. Also add the missing string.h include which is needed for the strlen() and strncmp() functions used by str_has_prefix() and the existing strncmp_static() macro. Signed-off-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260309195040.1019085-11-wander@redhat.com Signed-off-by: Tomas Glozar

rtla/actions: Simplify argument parsing

2026-03-10T09:32:37+00:00

The actions_parse() function uses open-coded logic to extract arguments from a string. This includes manual length checks and strncmp() calls, which can be verbose and error-prone. To simplify and improve the robustness of argument parsing, introduce a new extract_arg() helper macro. This macro extracts the value from a "key=value" pair, making the code more concise and readable. Also, introduce STRING_LENGTH() and strncmp_static() macros to perform compile-time calculations of string lengths and safer string comparisons. Refactor actions_parse() to use these new helpers, resulting in cleaner and more maintainable code. Signed-off-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260309195040.1019085-4-wander@redhat.com Signed-off-by: Tomas Glozar

rtla: Exit on memory allocation failures during initialization

2026-03-10T09:32:37+00:00

Most memory allocations in rtla happen during early initialization before any resources are acquired that would require cleanup. In these cases, propagating allocation errors just adds complexity without any benefit. There's nothing to clean up, and the program must exit anyway. This patch introduces fatal allocation wrappers (calloc_fatal, reallocarray_fatal, strdup_fatal) that call fatal() on allocation failure. These wrappers simplify the code by eliminating unnecessary error propagation paths. The patch converts early allocations to use these wrappers in actions_init() and related action functions, osnoise_context_alloc() and osnoise_init_tool(), trace_instance_init() and trace event functions, and parameter structure allocations in main functions. This simplifies the code while maintaining the same behavior: immediate exit on allocation failure during initialization. Allocations that require cleanup, such as those in histogram allocation functions with goto cleanup paths, are left unchanged and continue to return errors. Signed-off-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260309195040.1019085-2-wander@redhat.com Signed-off-by: Tomas Glozar

rtla/timerlat: Add --stack-format option

2026-03-04T14:51:56+00:00

In the current implementation, the auto-analysis code for printing the stack captured in the tracefs buffer of the aa instance stops at the first encountered address that cannot be resolved into a function symbol. This is not always the desired behavior on all platforms; sometimes, there might be resolvable entries after unresolvable ones, and sometimes, the user might want to inspect the raw pointers for the unresolvable entries. Add a new option, --stack-format, with three values: - truncate: stop at first unresolvable entry. This is the current behavior, and is kept as the default. - skip: skip unresolvable entries, but do not stop on them. - full: print all entries, including unresolvable ones. To make this work, the "size" field of the stack entry is now also read and used as the maximum number of entries to print, capped at 64, since that is the fixed length of the "caller" field. Link: https://lore.kernel.org/r/20260119115222.744150-1-tglozar@redhat.com Signed-off-by: Tomas Glozar

rtla: Use standard exit codes for result enum

2026-01-07T14:57:55+00:00

The result enum defines custom values for PASSED, ERROR, and FAILED. These values correspond to standard exit codes EXIT_SUCCESS and EXIT_FAILURE. Update the enum to use the standard macros EXIT_SUCCESS and EXIT_FAILURE to improve readability and adherence to standard C practices. The FAILED value is implicitly assigned EXIT_FAILURE + 1, so there is no need to assign an explicit value. Signed-off-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260106133655.249887-9-wander@redhat.com Signed-off-by: Tomas Glozar

rtla: Replace atoi() with a robust strtoi()

2026-01-07T14:57:55+00:00

The atoi() function does not perform error checking, which can lead to undefined behavior when parsing invalid or out-of-range strings. This can cause issues when parsing user-provided numerical inputs, such as signal numbers, PIDs, or CPU lists. To address this, introduce a new strtoi() helper function that safely converts a string to an integer. This function validates the input and checks for overflows, returning a negative value on failure. Replace all calls to atoi() with the new strtoi() function and add proper error handling to make the parsing more robust and prevent potential issues. Signed-off-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260106133655.249887-5-wander@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Remove unused function declarations

2026-01-06T09:11:59+00:00

Historically four function declarations remain orphaned or duplicated. Remove them to keep the source clean. Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20251012071133.290225-1-costa.shul@redhat.com Signed-off-by: Tomas Glozar

rtla: Fix -C/--cgroup interface

2025-11-21T09:30:27+00:00

Currently, user can only specify cgroup to the tracer's thread the following ways: `-C[cgroup]` `-C[=cgroup]` `--cgroup[=cgroup]` If user tries to specify cgroup as `-C [cgroup]` or `--cgroup [cgroup]`, the parser silently fails and rtla's cgroup is used for the tracer threads. To make interface more user-friendly, allow user to specify cgroup in the aforementioned way, i.e. `-C [cgroup]` and `--cgroup [cgroup]`. Refactor identical logic between -t/--trace and -C/--cgroup into a common function. Change documentation to reflect this user interface change. Fixes: a957cbc02531 ("rtla: Add -C cgroup support") Signed-off-by: Ivan Pravdin Reviewed-by: Tomas Glozar Link: https://lore.kernel.org/r/16132f1565cf5142b5fbd179975be370b529ced7.1762186418.git.ipravdin.official@gmail.com [ use capital letter in subject, as required by tracing subsystem ] Signed-off-by: Tomas Glozar