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Merge branch 'veristat: further usability improvements'
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Andrii Nakryiko says:

====================

A small patch set adding few usability improvements and features making
veristat a more convenient tool to be used for work on BPF verifier:

  - patch #2 speeds up and makes stats parsing from BPF verifier log more
    robust;

  - patch #3 makes veristat less strict about input object files; veristat
    will ignore non-BPF ELF files;

  - patch #4 adds progress log, by default, so that user doing
    mass-verification is aware that veristat is not stuck;

  - patch #5 allows to tune requested BPF verifier log level, which makes
    veristat a simplest way to get BPF verifier log, especially successfully
    verified ones.

v1->v2:
  - don't emit progress in non-table mode, as it breaks CSV output.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Alexei Starovoitov committed Sep 24, 2022
2 parents dbdea9b + e310efc commit 230bf13
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Showing 2 changed files with 118 additions and 19 deletions.
1 change: 1 addition & 0 deletions tools/testing/selftests/bpf/.gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@ test_cpp
/runqslower
/bench
/veristat
/sign-file
*.ko
*.tmp
xskxceiver
Expand Down
136 changes: 117 additions & 19 deletions tools/testing/selftests/bpf/veristat.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -61,6 +63,8 @@ static struct env {
char **filenames;
int filename_cnt;
bool verbose;
bool quiet;
int log_level;
enum resfmt out_fmt;
bool comparison_mode;

Expand All @@ -78,6 +82,11 @@ 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)
Expand All @@ -100,6 +109,8 @@ const char argp_program_doc[] =
static const struct argp_option opts[] = {
{ NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help" },
{ "verbose", 'v', NULL, 0, "Verbose mode" },
{ "log-level", 'l', "LEVEL", 0, "Verifier log level (default 0 for normal mode, 1 for verbose mode)" },
{ "quiet", 'q', NULL, 0, "Quiet mode" },
{ "emit", 'e', "SPEC", 0, "Specify stats to be emitted" },
{ "sort", 's', "SPEC", 0, "Specify sort order" },
{ "output-format", 'o', "FMT", 0, "Result output format (table, csv), default is table." },
Expand All @@ -124,6 +135,9 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
case 'v':
env.verbose = true;
break;
case 'q':
env.quiet = true;
break;
case 'e':
err = parse_stats(arg, &env.output_spec);
if (err)
Expand All @@ -144,6 +158,14 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
return -EINVAL;
}
break;
case 'l':
errno = 0;
env.log_level = strtol(arg, NULL, 10);
if (errno) {
fprintf(stderr, "invalid log level: %s\n", arg);
argp_usage(state);
}
break;
case 'C':
env.comparison_mode = true;
break;
Expand Down Expand Up @@ -226,8 +248,41 @@ 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) {
Expand Down Expand Up @@ -303,7 +358,7 @@ 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;
}

Expand Down Expand Up @@ -419,19 +474,30 @@ static void free_verif_stats(struct verif_stats *stats, size_t stat_cnt)

static char verif_log_buf[64 * 1024];

static int parse_verif_log(const char *buf, size_t buf_sz, struct verif_stats *s)
#define MAX_PARSED_LOG_LINES 100

static int parse_verif_log(char * const buf, size_t buf_sz, struct verif_stats *s)
{
const char *next;
int pos;
const char *cur;
int pos, lines;

for (pos = 0; buf[0]; buf = next) {
if (buf[0] == '\n')
buf++;
next = strchrnul(&buf[pos], '\n');
buf[buf_sz - 1] = '\0';

if (1 == sscanf(buf, "verification time %ld usec\n", &s->stats[DURATION]))
for (pos = strlen(buf) - 1, lines = 0; pos >= 0 && lines < MAX_PARSED_LOG_LINES; lines++) {
/* find previous endline or otherwise take the start of log buf */
for (cur = &buf[pos]; cur > buf && cur[0] != '\n'; cur--, pos--) {
}
/* next time start from end of previous line (or pos goes to <0) */
pos--;
/* if we found endline, point right after endline symbol;
* otherwise, stay at the beginning of log buf
*/
if (cur[0] == '\n')
cur++;

if (1 == sscanf(cur, "verification time %ld usec\n", &s->stats[DURATION]))
continue;
if (6 == sscanf(buf, "processed %ld insns (limit %*d) max_states_per_insn %ld total_states %ld peak_states %ld mark_read %ld",
if (6 == sscanf(cur, "processed %ld insns (limit %*d) max_states_per_insn %ld total_states %ld peak_states %ld mark_read %ld",
&s->stats[TOTAL_INSNS],
&s->stats[MAX_STATES_PER_INSN],
&s->stats[TOTAL_STATES],
Expand All @@ -452,8 +518,10 @@ 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)
Expand All @@ -468,14 +536,15 @@ static int process_prog(const char *filename, struct bpf_object *obj, struct bpf
if (!buf)
return -ENOMEM;
bpf_program__set_log_buf(prog, buf, buf_sz);
bpf_program__set_log_level(prog, 1 | 4); /* stats + log */
bpf_program__set_log_level(prog, env.log_level | 4); /* stats + log */
} else {
bpf_program__set_log_buf(prog, buf, buf_sz);
bpf_program__set_log_level(prog, 4); /* only verifier stats */
}
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));
Expand All @@ -502,18 +571,39 @@ 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);
if (!env.quiet && env.out_fmt == RESFMT_TABLE)
printf("Processing '%s'...\n", basename(filename));

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++;
}
Expand Down Expand Up @@ -721,8 +811,8 @@ 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);
}
}

Expand Down Expand Up @@ -1195,6 +1285,14 @@ int main(int argc, char **argv)
if (argp_parse(&argp, argc, argv, 0, NULL, NULL))
return 1;

if (env.verbose && env.quiet) {
fprintf(stderr, "Verbose and quiet modes are incompatible, please specify just one or neither!\n");
argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
return 1;
}
if (env.verbose && env.log_level == 0)
env.log_level = 1;

if (env.output_spec.spec_cnt == 0)
env.output_spec = default_output_spec;
if (env.sort_spec.spec_cnt == 0)
Expand Down

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