Several test_progs tests already capture libbpf log in order to check for some expected output, e.g bpf_tcp_ca.c, kfunc_dynptr_param.c, log_buf.c and a few others. This commit provides a, hopefully, simple API to capture libbpf log w/o necessity to define new print callback in each test: /* Creates a global memstream capturing INFO and WARN level output * passed to libbpf_print_fn. * Returns 0 on success, negative value on failure. * On failure the description is printed using PRINT_FAIL and * current test case is marked as fail. */ int start_libbpf_log_capture(void) /* Destroys global memstream created by start_libbpf_log_capture(). * Returns a pointer to captured data which has to be freed. * Returned buffer is null terminated. */ char *stop_libbpf_log_capture(void) The intended usage is as follows: if (start_libbpf_log_capture()) return; use_libbpf(); char *log = stop_libbpf_log_capture(); ASSERT_HAS_SUBSTR(log, "... expected ...", "expected some message"); free(log); As a safety measure, free(start_libbpf_log_capture()) is invoked in the epilogue of the test_progs.c:run_one_test(). Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240306104529.6453-6-eddyz87@gmail.com
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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