Commit 518fee8b authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

selftests/bpf: make veristat skip non-BPF and failing-to-open BPF objects 



Make veristat ignore non-BPF object files. This allows simpler
mass-verification (e.g., `sudo ./veristat *.bpf.o` in selftests/bpf
directory). Note that `sudo ./veristat *.o` would also work, but with
selftests's multiple copies of BPF object files (.bpf.o and
.bpf.linked{1,2,3}.o) it's 4x slower.

Also, given some of BPF object files could be incomplete in the sense
that they are meant to be statically linked into final BPF object file
(like linked_maps, linked_funcs, linked_vars), note such instances in
stderr, but proceed anyways. This seems like a better trade off between
completely silently ignoring BPF object file and aborting
mass-verification altogether.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220923175913.3272430-4-andrii@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c2488d70

tools/testing/selftests/bpf/veristat.c

+70 −8
Original line number Diff line number Diff line
@@ -15,6 +15,8 @@ 
#include <sys/sysinfo.h>

#include <sys/stat.h>

#include <bpf/libbpf.h>

#include <libelf.h>

#include <gelf.h>



enum stat_id {

	VERDICT,
@@ -78,6 +80,11 @@ static struct env { 
	struct filter *deny_filters;

	int allow_filter_cnt;

	int deny_filter_cnt;



	int files_processed;

	int files_skipped;

	int progs_processed;

	int progs_skipped;

} env;



static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args)
@@ -226,8 +233,41 @@ static bool should_process_file(const char *filename) 
	return false;

}



static bool should_process_prog(const char *filename, const char *prog_name)

static bool is_bpf_obj_file(const char *path) {

	Elf64_Ehdr *ehdr;

	int fd, err = -EINVAL;

	Elf *elf = NULL;



	fd = open(path, O_RDONLY | O_CLOEXEC);

	if (fd < 0)

		return true; /* we'll fail later and propagate error */



	/* ensure libelf is initialized */

	(void)elf_version(EV_CURRENT);



	elf = elf_begin(fd, ELF_C_READ, NULL);

	if (!elf)

		goto cleanup;



	if (elf_kind(elf) != ELF_K_ELF || gelf_getclass(elf) != ELFCLASS64)

		goto cleanup;



	ehdr = elf64_getehdr(elf);

	/* Old LLVM set e_machine to EM_NONE */

	if (!ehdr || ehdr->e_type != ET_REL || (ehdr->e_machine && ehdr->e_machine != EM_BPF))

		goto cleanup;



	err = 0;

cleanup:

	if (elf)

		elf_end(elf);

	close(fd);

	return err == 0;

}



static bool should_process_prog(const char *path, const char *prog_name)

{

	const char *filename = basename(path);

	int i;



	if (env.deny_filter_cnt > 0) {
@@ -303,7 +343,7 @@ static int append_filter_file(const char *path) 
	f = fopen(path, "r");

	if (!f) {

		err = -errno;

		fprintf(stderr, "Failed to open '%s': %d\n", path, err);

		fprintf(stderr, "Failed to open filters in '%s': %d\n", path, err);

		return err;

	}
@@ -463,8 +503,10 @@ static int process_prog(const char *filename, struct bpf_object *obj, struct bpf 
	int err = 0;

	void *tmp;



	if (!should_process_prog(basename(filename), bpf_program__name(prog)))

	if (!should_process_prog(filename, bpf_program__name(prog))) {

		env.progs_skipped++;

		return 0;

	}



	tmp = realloc(env.prog_stats, (env.prog_stat_cnt + 1) * sizeof(*env.prog_stats));

	if (!tmp)
@@ -487,6 +529,7 @@ static int process_prog(const char *filename, struct bpf_object *obj, struct bpf 
	verif_log_buf[0] = '\0';



	err = bpf_object__load(obj);

	env.progs_processed++;



	stats->file_name = strdup(basename(filename));

	stats->prog_name = strdup(bpf_program__name(prog));
@@ -513,18 +556,37 @@ static int process_obj(const char *filename) 
	LIBBPF_OPTS(bpf_object_open_opts, opts);

	int err = 0, prog_cnt = 0;



	if (!should_process_file(basename(filename)))

	if (!should_process_file(basename(filename))) {

		if (env.verbose)

			printf("Skipping '%s' due to filters...\n", filename);

		env.files_skipped++;

		return 0;

	}

	if (!is_bpf_obj_file(filename)) {

		if (env.verbose)

			printf("Skipping '%s' as it's not a BPF object file...\n", filename);

		env.files_skipped++;

		return 0;

	}



	old_libbpf_print_fn = libbpf_set_print(libbpf_print_fn);



	obj = bpf_object__open_file(filename, &opts);

	if (!obj) {

		err = -errno;

		fprintf(stderr, "Failed to open '%s': %d\n", filename, err);

		/* if libbpf can't open BPF object file, it could be because

		 * that BPF object file is incomplete and has to be statically

		 * linked into a final BPF object file; instead of bailing

		 * out, report it into stderr, mark it as skipped, and

		 * proceeed

		 */

		fprintf(stderr, "Failed to open '%s': %d\n", filename, -errno);

		env.files_skipped++;

		err = 0;

		goto cleanup;

	}



	env.files_processed++;



	bpf_object__for_each_program(prog, obj) {

		prog_cnt++;

	}
@@ -732,8 +794,8 @@ static void output_stats(const struct verif_stats *s, enum resfmt fmt, bool last 


	if (last && fmt == RESFMT_TABLE) {

		output_header_underlines();

		printf("Done. Processed %d object files, %d programs.\n",

		       env.filename_cnt, env.prog_stat_cnt);

		printf("Done. Processed %d files, %d programs. Skipped %d files, %d programs.\n",

		       env.files_processed, env.files_skipped, env.progs_processed, env.progs_skipped);

	}

}