Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2102 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/veristat.c b/tools/testing/selftests/bpf/veristat.c
new file mode 100644
index 0000000000..655095810d
--- /dev/null
+++ b/tools/testing/selftests/bpf/veristat.c
@@ -0,0 +1,2102 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+#define _GNU_SOURCE
+#include <argp.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sched.h>
+#include <pthread.h>
+#include <dirent.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/sysinfo.h>
+#include <sys/stat.h>
+#include <bpf/libbpf.h>
+#include <bpf/btf.h>
+#include <libelf.h>
+#include <gelf.h>
+#include <float.h>
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+#endif
+
+enum stat_id {
+	VERDICT,
+	DURATION,
+	TOTAL_INSNS,
+	TOTAL_STATES,
+	PEAK_STATES,
+	MAX_STATES_PER_INSN,
+	MARK_READ_MAX_LEN,
+
+	FILE_NAME,
+	PROG_NAME,
+
+	ALL_STATS_CNT,
+	NUM_STATS_CNT = FILE_NAME - VERDICT,
+};
+
+/* In comparison mode each stat can specify up to four different values:
+ *   - A side value;
+ *   - B side value;
+ *   - absolute diff value;
+ *   - relative (percentage) diff value.
+ *
+ * When specifying stat specs in comparison mode, user can use one of the
+ * following variant suffixes to specify which exact variant should be used for
+ * ordering or filtering:
+ *   - `_a` for A side value;
+ *   - `_b` for B side value;
+ *   - `_diff` for absolute diff value;
+ *   - `_pct` for relative (percentage) diff value.
+ *
+ * If no variant suffix is provided, then `_b` (control data) is assumed.
+ *
+ * As an example, let's say instructions stat has the following output:
+ *
+ * Insns (A)  Insns (B)  Insns   (DIFF)
+ * ---------  ---------  --------------
+ * 21547      20920       -627 (-2.91%)
+ *
+ * Then:
+ *   - 21547 is A side value (insns_a);
+ *   - 20920 is B side value (insns_b);
+ *   - -627 is absolute diff value (insns_diff);
+ *   - -2.91% is relative diff value (insns_pct).
+ *
+ * For verdict there is no verdict_pct variant.
+ * For file and program name, _a and _b variants are equivalent and there are
+ * no _diff or _pct variants.
+ */
+enum stat_variant {
+	VARIANT_A,
+	VARIANT_B,
+	VARIANT_DIFF,
+	VARIANT_PCT,
+};
+
+struct verif_stats {
+	char *file_name;
+	char *prog_name;
+
+	long stats[NUM_STATS_CNT];
+};
+
+/* joined comparison mode stats */
+struct verif_stats_join {
+	char *file_name;
+	char *prog_name;
+
+	const struct verif_stats *stats_a;
+	const struct verif_stats *stats_b;
+};
+
+struct stat_specs {
+	int spec_cnt;
+	enum stat_id ids[ALL_STATS_CNT];
+	enum stat_variant variants[ALL_STATS_CNT];
+	bool asc[ALL_STATS_CNT];
+	int lens[ALL_STATS_CNT * 3]; /* 3x for comparison mode */
+};
+
+enum resfmt {
+	RESFMT_TABLE,
+	RESFMT_TABLE_CALCLEN, /* fake format to pre-calculate table's column widths */
+	RESFMT_CSV,
+};
+
+enum filter_kind {
+	FILTER_NAME,
+	FILTER_STAT,
+};
+
+enum operator_kind {
+	OP_EQ,		/* == or = */
+	OP_NEQ,		/* != or <> */
+	OP_LT,		/* < */
+	OP_LE,		/* <= */
+	OP_GT,		/* > */
+	OP_GE,		/* >= */
+};
+
+struct filter {
+	enum filter_kind kind;
+	/* FILTER_NAME */
+	char *any_glob;
+	char *file_glob;
+	char *prog_glob;
+	/* FILTER_STAT */
+	enum operator_kind op;
+	int stat_id;
+	enum stat_variant stat_var;
+	long value;
+};
+
+static struct env {
+	char **filenames;
+	int filename_cnt;
+	bool verbose;
+	bool debug;
+	bool quiet;
+	bool force_checkpoints;
+	enum resfmt out_fmt;
+	bool show_version;
+	bool comparison_mode;
+	bool replay_mode;
+
+	int log_level;
+	int log_size;
+	bool log_fixed;
+
+	struct verif_stats *prog_stats;
+	int prog_stat_cnt;
+
+	/* baseline_stats is allocated and used only in comparison mode */
+	struct verif_stats *baseline_stats;
+	int baseline_stat_cnt;
+
+	struct verif_stats_join *join_stats;
+	int join_stat_cnt;
+
+	struct stat_specs output_spec;
+	struct stat_specs sort_spec;
+
+	struct filter *allow_filters;
+	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)
+{
+	if (!env.verbose)
+		return 0;
+	if (level == LIBBPF_DEBUG  && !env.debug)
+		return 0;
+	return vfprintf(stderr, format, args);
+}
+
+#ifndef VERISTAT_VERSION
+#define VERISTAT_VERSION "<kernel>"
+#endif
+
+const char *argp_program_version = "veristat v" VERISTAT_VERSION;
+const char *argp_program_bug_address = "<bpf@vger.kernel.org>";
+const char argp_program_doc[] =
+"veristat    BPF verifier stats collection and comparison tool.\n"
+"\n"
+"USAGE: veristat <obj-file> [<obj-file>...]\n"
+"   OR: veristat -C <baseline.csv> <comparison.csv>\n"
+"   OR: veristat -R <results.csv>\n";
+
+enum {
+	OPT_LOG_FIXED = 1000,
+	OPT_LOG_SIZE = 1001,
+};
+
+static const struct argp_option opts[] = {
+	{ NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help" },
+	{ "version", 'V', NULL, 0, "Print version" },
+	{ "verbose", 'v', NULL, 0, "Verbose mode" },
+	{ "debug", 'd', NULL, 0, "Debug mode (turns on libbpf debug logging)" },
+	{ "log-level", 'l', "LEVEL", 0, "Verifier log level (default 0 for normal mode, 1 for verbose mode)" },
+	{ "log-fixed", OPT_LOG_FIXED, NULL, 0, "Disable verifier log rotation" },
+	{ "log-size", OPT_LOG_SIZE, "BYTES", 0, "Customize verifier log size (default to 16MB)" },
+	{ "test-states", 't', NULL, 0,
+	  "Force frequent BPF verifier state checkpointing (set BPF_F_TEST_STATE_FREQ program flag)" },
+	{ "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." },
+	{ "compare", 'C', NULL, 0, "Comparison mode" },
+	{ "replay", 'R', NULL, 0, "Replay mode" },
+	{ "filter", 'f', "FILTER", 0, "Filter expressions (or @filename for file with expressions)." },
+	{},
+};
+
+static int parse_stats(const char *stats_str, struct stat_specs *specs);
+static int append_filter(struct filter **filters, int *cnt, const char *str);
+static int append_filter_file(const char *path);
+
+static error_t parse_arg(int key, char *arg, struct argp_state *state)
+{
+	void *tmp;
+	int err;
+
+	switch (key) {
+	case 'h':
+		argp_state_help(state, stderr, ARGP_HELP_STD_HELP);
+		break;
+	case 'V':
+		env.show_version = true;
+		break;
+	case 'v':
+		env.verbose = true;
+		break;
+	case 'd':
+		env.debug = true;
+		env.verbose = true;
+		break;
+	case 'q':
+		env.quiet = true;
+		break;
+	case 'e':
+		err = parse_stats(arg, &env.output_spec);
+		if (err)
+			return err;
+		break;
+	case 's':
+		err = parse_stats(arg, &env.sort_spec);
+		if (err)
+			return err;
+		break;
+	case 'o':
+		if (strcmp(arg, "table") == 0) {
+			env.out_fmt = RESFMT_TABLE;
+		} else if (strcmp(arg, "csv") == 0) {
+			env.out_fmt = RESFMT_CSV;
+		} else {
+			fprintf(stderr, "Unrecognized output format '%s'\n", arg);
+			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 OPT_LOG_FIXED:
+		env.log_fixed = true;
+		break;
+	case OPT_LOG_SIZE:
+		errno = 0;
+		env.log_size = strtol(arg, NULL, 10);
+		if (errno) {
+			fprintf(stderr, "invalid log size: %s\n", arg);
+			argp_usage(state);
+		}
+		break;
+	case 't':
+		env.force_checkpoints = true;
+		break;
+	case 'C':
+		env.comparison_mode = true;
+		break;
+	case 'R':
+		env.replay_mode = true;
+		break;
+	case 'f':
+		if (arg[0] == '@')
+			err = append_filter_file(arg + 1);
+		else if (arg[0] == '!')
+			err = append_filter(&env.deny_filters, &env.deny_filter_cnt, arg + 1);
+		else
+			err = append_filter(&env.allow_filters, &env.allow_filter_cnt, arg);
+		if (err) {
+			fprintf(stderr, "Failed to collect program filter expressions: %d\n", err);
+			return err;
+		}
+		break;
+	case ARGP_KEY_ARG:
+		tmp = realloc(env.filenames, (env.filename_cnt + 1) * sizeof(*env.filenames));
+		if (!tmp)
+			return -ENOMEM;
+		env.filenames = tmp;
+		env.filenames[env.filename_cnt] = strdup(arg);
+		if (!env.filenames[env.filename_cnt])
+			return -ENOMEM;
+		env.filename_cnt++;
+		break;
+	default:
+		return ARGP_ERR_UNKNOWN;
+	}
+	return 0;
+}
+
+static const struct argp argp = {
+	.options = opts,
+	.parser = parse_arg,
+	.doc = argp_program_doc,
+};
+
+
+/* Adapted from perf/util/string.c */
+static bool glob_matches(const char *str, const char *pat)
+{
+	while (*str && *pat && *pat != '*') {
+		if (*str != *pat)
+			return false;
+		str++;
+		pat++;
+	}
+	/* Check wild card */
+	if (*pat == '*') {
+		while (*pat == '*')
+			pat++;
+		if (!*pat) /* Tail wild card matches all */
+			return true;
+		while (*str)
+			if (glob_matches(str++, pat))
+				return true;
+	}
+	return !*str && !*pat;
+}
+
+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_file_prog(const char *filename, const char *prog_name)
+{
+	struct filter *f;
+	int i, allow_cnt = 0;
+
+	for (i = 0; i < env.deny_filter_cnt; i++) {
+		f = &env.deny_filters[i];
+		if (f->kind != FILTER_NAME)
+			continue;
+
+		if (f->any_glob && glob_matches(filename, f->any_glob))
+			return false;
+		if (f->any_glob && prog_name && glob_matches(prog_name, f->any_glob))
+			return false;
+		if (f->file_glob && glob_matches(filename, f->file_glob))
+			return false;
+		if (f->prog_glob && prog_name && glob_matches(prog_name, f->prog_glob))
+			return false;
+	}
+
+	for (i = 0; i < env.allow_filter_cnt; i++) {
+		f = &env.allow_filters[i];
+		if (f->kind != FILTER_NAME)
+			continue;
+
+		allow_cnt++;
+		if (f->any_glob) {
+			if (glob_matches(filename, f->any_glob))
+				return true;
+			/* If we don't know program name yet, any_glob filter
+			 * has to assume that current BPF object file might be
+			 * relevant; we'll check again later on after opening
+			 * BPF object file, at which point program name will
+			 * be known finally.
+			 */
+			if (!prog_name || glob_matches(prog_name, f->any_glob))
+				return true;
+		} else {
+			if (f->file_glob && !glob_matches(filename, f->file_glob))
+				continue;
+			if (f->prog_glob && prog_name && !glob_matches(prog_name, f->prog_glob))
+				continue;
+			return true;
+		}
+	}
+
+	/* if there are no file/prog name allow filters, allow all progs,
+	 * unless they are denied earlier explicitly
+	 */
+	return allow_cnt == 0;
+}
+
+static struct {
+	enum operator_kind op_kind;
+	const char *op_str;
+} operators[] = {
+	/* Order of these definitions matter to avoid situations like '<'
+	 * matching part of what is actually a '<>' operator. That is,
+	 * substrings should go last.
+	 */
+	{ OP_EQ, "==" },
+	{ OP_NEQ, "!=" },
+	{ OP_NEQ, "<>" },
+	{ OP_LE, "<=" },
+	{ OP_LT, "<" },
+	{ OP_GE, ">=" },
+	{ OP_GT, ">" },
+	{ OP_EQ, "=" },
+};
+
+static bool parse_stat_id_var(const char *name, size_t len, int *id, enum stat_variant *var);
+
+static int append_filter(struct filter **filters, int *cnt, const char *str)
+{
+	struct filter *f;
+	void *tmp;
+	const char *p;
+	int i;
+
+	tmp = realloc(*filters, (*cnt + 1) * sizeof(**filters));
+	if (!tmp)
+		return -ENOMEM;
+	*filters = tmp;
+
+	f = &(*filters)[*cnt];
+	memset(f, 0, sizeof(*f));
+
+	/* First, let's check if it's a stats filter of the following form:
+	 * <stat><op><value, where:
+	 *   - <stat> is one of supported numerical stats (verdict is also
+	 *     considered numerical, failure == 0, success == 1);
+	 *   - <op> is comparison operator (see `operators` definitions);
+	 *   - <value> is an integer (or failure/success, or false/true as
+	 *     special aliases for 0 and 1, respectively).
+	 * If the form doesn't match what user provided, we assume file/prog
+	 * glob filter.
+	 */
+	for (i = 0; i < ARRAY_SIZE(operators); i++) {
+		enum stat_variant var;
+		int id;
+		long val;
+		const char *end = str;
+		const char *op_str;
+
+		op_str = operators[i].op_str;
+		p = strstr(str, op_str);
+		if (!p)
+			continue;
+
+		if (!parse_stat_id_var(str, p - str, &id, &var)) {
+			fprintf(stderr, "Unrecognized stat name in '%s'!\n", str);
+			return -EINVAL;
+		}
+		if (id >= FILE_NAME) {
+			fprintf(stderr, "Non-integer stat is specified in '%s'!\n", str);
+			return -EINVAL;
+		}
+
+		p += strlen(op_str);
+
+		if (strcasecmp(p, "true") == 0 ||
+		    strcasecmp(p, "t") == 0 ||
+		    strcasecmp(p, "success") == 0 ||
+		    strcasecmp(p, "succ") == 0 ||
+		    strcasecmp(p, "s") == 0 ||
+		    strcasecmp(p, "match") == 0 ||
+		    strcasecmp(p, "m") == 0) {
+			val = 1;
+		} else if (strcasecmp(p, "false") == 0 ||
+			   strcasecmp(p, "f") == 0 ||
+			   strcasecmp(p, "failure") == 0 ||
+			   strcasecmp(p, "fail") == 0 ||
+			   strcasecmp(p, "mismatch") == 0 ||
+			   strcasecmp(p, "mis") == 0) {
+			val = 0;
+		} else {
+			errno = 0;
+			val = strtol(p, (char **)&end, 10);
+			if (errno || end == p || *end != '\0' ) {
+				fprintf(stderr, "Invalid integer value in '%s'!\n", str);
+				return -EINVAL;
+			}
+		}
+
+		f->kind = FILTER_STAT;
+		f->stat_id = id;
+		f->stat_var = var;
+		f->op = operators[i].op_kind;
+		f->value = val;
+
+		*cnt += 1;
+		return 0;
+	}
+
+	/* File/prog filter can be specified either as '<glob>' or
+	 * '<file-glob>/<prog-glob>'. In the former case <glob> is applied to
+	 * both file and program names. This seems to be way more useful in
+	 * practice. If user needs full control, they can use '/<prog-glob>'
+	 * form to glob just program name, or '<file-glob>/' to glob only file
+	 * name. But usually common <glob> seems to be the most useful and
+	 * ergonomic way.
+	 */
+	f->kind = FILTER_NAME;
+	p = strchr(str, '/');
+	if (!p) {
+		f->any_glob = strdup(str);
+		if (!f->any_glob)
+			return -ENOMEM;
+	} else {
+		if (str != p) {
+			/* non-empty file glob */
+			f->file_glob = strndup(str, p - str);
+			if (!f->file_glob)
+				return -ENOMEM;
+		}
+		if (strlen(p + 1) > 0) {
+			/* non-empty prog glob */
+			f->prog_glob = strdup(p + 1);
+			if (!f->prog_glob) {
+				free(f->file_glob);
+				f->file_glob = NULL;
+				return -ENOMEM;
+			}
+		}
+	}
+
+	*cnt += 1;
+	return 0;
+}
+
+static int append_filter_file(const char *path)
+{
+	char buf[1024];
+	FILE *f;
+	int err = 0;
+
+	f = fopen(path, "r");
+	if (!f) {
+		err = -errno;
+		fprintf(stderr, "Failed to open filters in '%s': %d\n", path, err);
+		return err;
+	}
+
+	while (fscanf(f, " %1023[^\n]\n", buf) == 1) {
+		/* lines starting with # are comments, skip them */
+		if (buf[0] == '\0' || buf[0] == '#')
+			continue;
+		/* lines starting with ! are negative match filters */
+		if (buf[0] == '!')
+			err = append_filter(&env.deny_filters, &env.deny_filter_cnt, buf + 1);
+		else
+			err = append_filter(&env.allow_filters, &env.allow_filter_cnt, buf);
+		if (err)
+			goto cleanup;
+	}
+
+cleanup:
+	fclose(f);
+	return err;
+}
+
+static const struct stat_specs default_output_spec = {
+	.spec_cnt = 7,
+	.ids = {
+		FILE_NAME, PROG_NAME, VERDICT, DURATION,
+		TOTAL_INSNS, TOTAL_STATES, PEAK_STATES,
+	},
+};
+
+static const struct stat_specs default_csv_output_spec = {
+	.spec_cnt = 9,
+	.ids = {
+		FILE_NAME, PROG_NAME, VERDICT, DURATION,
+		TOTAL_INSNS, TOTAL_STATES, PEAK_STATES,
+		MAX_STATES_PER_INSN, MARK_READ_MAX_LEN,
+	},
+};
+
+static const struct stat_specs default_sort_spec = {
+	.spec_cnt = 2,
+	.ids = {
+		FILE_NAME, PROG_NAME,
+	},
+	.asc = { true, true, },
+};
+
+/* sorting for comparison mode to join two data sets */
+static const struct stat_specs join_sort_spec = {
+	.spec_cnt = 2,
+	.ids = {
+		FILE_NAME, PROG_NAME,
+	},
+	.asc = { true, true, },
+};
+
+static struct stat_def {
+	const char *header;
+	const char *names[4];
+	bool asc_by_default;
+	bool left_aligned;
+} stat_defs[] = {
+	[FILE_NAME] = { "File", {"file_name", "filename", "file"}, true /* asc */, true /* left */ },
+	[PROG_NAME] = { "Program", {"prog_name", "progname", "prog"}, true /* asc */, true /* left */ },
+	[VERDICT] = { "Verdict", {"verdict"}, true /* asc: failure, success */, true /* left */ },
+	[DURATION] = { "Duration (us)", {"duration", "dur"}, },
+	[TOTAL_INSNS] = { "Insns", {"total_insns", "insns"}, },
+	[TOTAL_STATES] = { "States", {"total_states", "states"}, },
+	[PEAK_STATES] = { "Peak states", {"peak_states"}, },
+	[MAX_STATES_PER_INSN] = { "Max states per insn", {"max_states_per_insn"}, },
+	[MARK_READ_MAX_LEN] = { "Max mark read length", {"max_mark_read_len", "mark_read"}, },
+};
+
+static bool parse_stat_id_var(const char *name, size_t len, int *id, enum stat_variant *var)
+{
+	static const char *var_sfxs[] = {
+		[VARIANT_A] = "_a",
+		[VARIANT_B] = "_b",
+		[VARIANT_DIFF] = "_diff",
+		[VARIANT_PCT] = "_pct",
+	};
+	int i, j, k;
+
+	for (i = 0; i < ARRAY_SIZE(stat_defs); i++) {
+		struct stat_def *def = &stat_defs[i];
+		size_t alias_len, sfx_len;
+		const char *alias;
+
+		for (j = 0; j < ARRAY_SIZE(stat_defs[i].names); j++) {
+			alias = def->names[j];
+			if (!alias)
+				continue;
+
+			alias_len = strlen(alias);
+			if (strncmp(name, alias, alias_len) != 0)
+				continue;
+
+			if (alias_len == len) {
+				/* If no variant suffix is specified, we
+				 * assume control group (just in case we are
+				 * in comparison mode. Variant is ignored in
+				 * non-comparison mode.
+				 */
+				*var = VARIANT_B;
+				*id = i;
+				return true;
+			}
+
+			for (k = 0; k < ARRAY_SIZE(var_sfxs); k++) {
+				sfx_len = strlen(var_sfxs[k]);
+				if (alias_len + sfx_len != len)
+					continue;
+
+				if (strncmp(name + alias_len, var_sfxs[k], sfx_len) == 0) {
+					*var = (enum stat_variant)k;
+					*id = i;
+					return true;
+				}
+			}
+		}
+	}
+
+	return false;
+}
+
+static bool is_asc_sym(char c)
+{
+	return c == '^';
+}
+
+static bool is_desc_sym(char c)
+{
+	return c == 'v' || c == 'V' || c == '.' || c == '!' || c == '_';
+}
+
+static int parse_stat(const char *stat_name, struct stat_specs *specs)
+{
+	int id;
+	bool has_order = false, is_asc = false;
+	size_t len = strlen(stat_name);
+	enum stat_variant var;
+
+	if (specs->spec_cnt >= ARRAY_SIZE(specs->ids)) {
+		fprintf(stderr, "Can't specify more than %zd stats\n", ARRAY_SIZE(specs->ids));
+		return -E2BIG;
+	}
+
+	if (len > 1 && (is_asc_sym(stat_name[len - 1]) || is_desc_sym(stat_name[len - 1]))) {
+		has_order = true;
+		is_asc = is_asc_sym(stat_name[len - 1]);
+		len -= 1;
+	}
+
+	if (!parse_stat_id_var(stat_name, len, &id, &var)) {
+		fprintf(stderr, "Unrecognized stat name '%s'\n", stat_name);
+		return -ESRCH;
+	}
+
+	specs->ids[specs->spec_cnt] = id;
+	specs->variants[specs->spec_cnt] = var;
+	specs->asc[specs->spec_cnt] = has_order ? is_asc : stat_defs[id].asc_by_default;
+	specs->spec_cnt++;
+
+	return 0;
+}
+
+static int parse_stats(const char *stats_str, struct stat_specs *specs)
+{
+	char *input, *state = NULL, *next;
+	int err;
+
+	input = strdup(stats_str);
+	if (!input)
+		return -ENOMEM;
+
+	while ((next = strtok_r(state ? NULL : input, ",", &state))) {
+		err = parse_stat(next, specs);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static void free_verif_stats(struct verif_stats *stats, size_t stat_cnt)
+{
+	int i;
+
+	if (!stats)
+		return;
+
+	for (i = 0; i < stat_cnt; i++) {
+		free(stats[i].file_name);
+		free(stats[i].prog_name);
+	}
+	free(stats);
+}
+
+static char verif_log_buf[64 * 1024];
+
+#define MAX_PARSED_LOG_LINES 100
+
+static int parse_verif_log(char * const buf, size_t buf_sz, struct verif_stats *s)
+{
+	const char *cur;
+	int pos, lines;
+
+	buf[buf_sz - 1] = '\0';
+
+	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(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],
+				&s->stats[PEAK_STATES],
+				&s->stats[MARK_READ_MAX_LEN]))
+			continue;
+	}
+
+	return 0;
+}
+
+static int guess_prog_type_by_ctx_name(const char *ctx_name,
+				       enum bpf_prog_type *prog_type,
+				       enum bpf_attach_type *attach_type)
+{
+	/* We need to guess program type based on its declared context type.
+	 * This guess can't be perfect as many different program types might
+	 * share the same context type.  So we can only hope to reasonably
+	 * well guess this and get lucky.
+	 *
+	 * Just in case, we support both UAPI-side type names and
+	 * kernel-internal names.
+	 */
+	static struct {
+		const char *uapi_name;
+		const char *kern_name;
+		enum bpf_prog_type prog_type;
+		enum bpf_attach_type attach_type;
+	} ctx_map[] = {
+		/* __sk_buff is most ambiguous, we assume TC program */
+		{ "__sk_buff", "sk_buff", BPF_PROG_TYPE_SCHED_CLS },
+		{ "bpf_sock", "sock", BPF_PROG_TYPE_CGROUP_SOCK, BPF_CGROUP_INET4_POST_BIND },
+		{ "bpf_sock_addr", "bpf_sock_addr_kern",  BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND },
+		{ "bpf_sock_ops", "bpf_sock_ops_kern", BPF_PROG_TYPE_SOCK_OPS, BPF_CGROUP_SOCK_OPS },
+		{ "sk_msg_md", "sk_msg", BPF_PROG_TYPE_SK_MSG, BPF_SK_MSG_VERDICT },
+		{ "bpf_cgroup_dev_ctx", "bpf_cgroup_dev_ctx", BPF_PROG_TYPE_CGROUP_DEVICE, BPF_CGROUP_DEVICE },
+		{ "bpf_sysctl", "bpf_sysctl_kern", BPF_PROG_TYPE_CGROUP_SYSCTL, BPF_CGROUP_SYSCTL },
+		{ "bpf_sockopt", "bpf_sockopt_kern", BPF_PROG_TYPE_CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT },
+		{ "sk_reuseport_md", "sk_reuseport_kern", BPF_PROG_TYPE_SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT_OR_MIGRATE },
+		{ "bpf_sk_lookup", "bpf_sk_lookup_kern", BPF_PROG_TYPE_SK_LOOKUP, BPF_SK_LOOKUP },
+		{ "xdp_md", "xdp_buff", BPF_PROG_TYPE_XDP, BPF_XDP },
+		/* tracing types with no expected attach type */
+		{ "bpf_user_pt_regs_t", "pt_regs", BPF_PROG_TYPE_KPROBE },
+		{ "bpf_perf_event_data", "bpf_perf_event_data_kern", BPF_PROG_TYPE_PERF_EVENT },
+		/* raw_tp programs use u64[] from kernel side, we don't want
+		 * to match on that, probably; so NULL for kern-side type
+		 */
+		{ "bpf_raw_tracepoint_args", NULL, BPF_PROG_TYPE_RAW_TRACEPOINT },
+	};
+	int i;
+
+	if (!ctx_name)
+		return -EINVAL;
+
+	for (i = 0; i < ARRAY_SIZE(ctx_map); i++) {
+		if (strcmp(ctx_map[i].uapi_name, ctx_name) == 0 ||
+		    (ctx_map[i].kern_name && strcmp(ctx_map[i].kern_name, ctx_name) == 0)) {
+			*prog_type = ctx_map[i].prog_type;
+			*attach_type = ctx_map[i].attach_type;
+			return 0;
+		}
+	}
+
+	return -ESRCH;
+}
+
+static void fixup_obj(struct bpf_object *obj, struct bpf_program *prog, const char *filename)
+{
+	struct bpf_map *map;
+
+	bpf_object__for_each_map(map, obj) {
+		/* disable pinning */
+		bpf_map__set_pin_path(map, NULL);
+
+		/* fix up map size, if necessary */
+		switch (bpf_map__type(map)) {
+		case BPF_MAP_TYPE_SK_STORAGE:
+		case BPF_MAP_TYPE_TASK_STORAGE:
+		case BPF_MAP_TYPE_INODE_STORAGE:
+		case BPF_MAP_TYPE_CGROUP_STORAGE:
+			break;
+		default:
+			if (bpf_map__max_entries(map) == 0)
+				bpf_map__set_max_entries(map, 1);
+		}
+	}
+
+	/* SEC(freplace) programs can't be loaded with veristat as is,
+	 * but we can try guessing their target program's expected type by
+	 * looking at the type of program's first argument and substituting
+	 * corresponding program type
+	 */
+	if (bpf_program__type(prog) == BPF_PROG_TYPE_EXT) {
+		const struct btf *btf = bpf_object__btf(obj);
+		const char *prog_name = bpf_program__name(prog);
+		enum bpf_prog_type prog_type;
+		enum bpf_attach_type attach_type;
+		const struct btf_type *t;
+		const char *ctx_name;
+		int id;
+
+		if (!btf)
+			goto skip_freplace_fixup;
+
+		id = btf__find_by_name_kind(btf, prog_name, BTF_KIND_FUNC);
+		t = btf__type_by_id(btf, id);
+		t = btf__type_by_id(btf, t->type);
+		if (!btf_is_func_proto(t) || btf_vlen(t) != 1)
+			goto skip_freplace_fixup;
+
+		/* context argument is a pointer to a struct/typedef */
+		t = btf__type_by_id(btf, btf_params(t)[0].type);
+		while (t && btf_is_mod(t))
+			t = btf__type_by_id(btf, t->type);
+		if (!t || !btf_is_ptr(t))
+			goto skip_freplace_fixup;
+		t = btf__type_by_id(btf, t->type);
+		while (t && btf_is_mod(t))
+			t = btf__type_by_id(btf, t->type);
+		if (!t)
+			goto skip_freplace_fixup;
+
+		ctx_name = btf__name_by_offset(btf, t->name_off);
+
+		if (guess_prog_type_by_ctx_name(ctx_name, &prog_type, &attach_type) == 0) {
+			bpf_program__set_type(prog, prog_type);
+			bpf_program__set_expected_attach_type(prog, attach_type);
+
+			if (!env.quiet) {
+				printf("Using guessed program type '%s' for %s/%s...\n",
+					libbpf_bpf_prog_type_str(prog_type),
+					filename, prog_name);
+			}
+		} else {
+			if (!env.quiet) {
+				printf("Failed to guess program type for freplace program with context type name '%s' for %s/%s. Consider using canonical type names to help veristat...\n",
+					ctx_name, filename, prog_name);
+			}
+		}
+	}
+skip_freplace_fixup:
+	return;
+}
+
+static int process_prog(const char *filename, struct bpf_object *obj, struct bpf_program *prog)
+{
+	const char *prog_name = bpf_program__name(prog);
+	const char *base_filename = basename(filename);
+	char *buf;
+	int buf_sz, log_level;
+	struct verif_stats *stats;
+	int err = 0;
+	void *tmp;
+
+	if (!should_process_file_prog(base_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)
+		return -ENOMEM;
+	env.prog_stats = tmp;
+	stats = &env.prog_stats[env.prog_stat_cnt++];
+	memset(stats, 0, sizeof(*stats));
+
+	if (env.verbose) {
+		buf_sz = env.log_size ? env.log_size : 16 * 1024 * 1024;
+		buf = malloc(buf_sz);
+		if (!buf)
+			return -ENOMEM;
+		/* ensure we always request stats */
+		log_level = env.log_level | 4 | (env.log_fixed ? 8 : 0);
+	} else {
+		buf = verif_log_buf;
+		buf_sz = sizeof(verif_log_buf);
+		/* request only verifier stats */
+		log_level = 4 | (env.log_fixed ? 8 : 0);
+	}
+	verif_log_buf[0] = '\0';
+
+	bpf_program__set_log_buf(prog, buf, buf_sz);
+	bpf_program__set_log_level(prog, log_level);
+
+	/* increase chances of successful BPF object loading */
+	fixup_obj(obj, prog, base_filename);
+
+	if (env.force_checkpoints)
+		bpf_program__set_flags(prog, bpf_program__flags(prog) | BPF_F_TEST_STATE_FREQ);
+
+	err = bpf_object__load(obj);
+	env.progs_processed++;
+
+	stats->file_name = strdup(base_filename);
+	stats->prog_name = strdup(bpf_program__name(prog));
+	stats->stats[VERDICT] = err == 0; /* 1 - success, 0 - failure */
+	parse_verif_log(buf, buf_sz, stats);
+
+	if (env.verbose) {
+		printf("PROCESSING %s/%s, DURATION US: %ld, VERDICT: %s, VERIFIER LOG:\n%s\n",
+		       filename, prog_name, stats->stats[DURATION],
+		       err ? "failure" : "success", buf);
+	}
+
+	if (verif_log_buf != buf)
+		free(buf);
+
+	return 0;
+};
+
+static int process_obj(const char *filename)
+{
+	struct bpf_object *obj = NULL, *tobj;
+	struct bpf_program *prog, *tprog, *lprog;
+	libbpf_print_fn_t old_libbpf_print_fn;
+	LIBBPF_OPTS(bpf_object_open_opts, opts);
+	int err = 0, prog_cnt = 0;
+
+	if (!should_process_file_prog(basename(filename), NULL)) {
+		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;
+	}
+
+	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) {
+		/* 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
+		 * proceed
+		 */
+		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++;
+	}
+
+	if (prog_cnt == 1) {
+		prog = bpf_object__next_program(obj, NULL);
+		bpf_program__set_autoload(prog, true);
+		process_prog(filename, obj, prog);
+		goto cleanup;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		const char *prog_name = bpf_program__name(prog);
+
+		tobj = bpf_object__open_file(filename, &opts);
+		if (!tobj) {
+			err = -errno;
+			fprintf(stderr, "Failed to open '%s': %d\n", filename, err);
+			goto cleanup;
+		}
+
+		lprog = NULL;
+		bpf_object__for_each_program(tprog, tobj) {
+			const char *tprog_name = bpf_program__name(tprog);
+
+			if (strcmp(prog_name, tprog_name) == 0) {
+				bpf_program__set_autoload(tprog, true);
+				lprog = tprog;
+			} else {
+				bpf_program__set_autoload(tprog, false);
+			}
+		}
+
+		process_prog(filename, tobj, lprog);
+		bpf_object__close(tobj);
+	}
+
+cleanup:
+	bpf_object__close(obj);
+	libbpf_set_print(old_libbpf_print_fn);
+	return err;
+}
+
+static int cmp_stat(const struct verif_stats *s1, const struct verif_stats *s2,
+		    enum stat_id id, bool asc)
+{
+	int cmp = 0;
+
+	switch (id) {
+	case FILE_NAME:
+		cmp = strcmp(s1->file_name, s2->file_name);
+		break;
+	case PROG_NAME:
+		cmp = strcmp(s1->prog_name, s2->prog_name);
+		break;
+	case VERDICT:
+	case DURATION:
+	case TOTAL_INSNS:
+	case TOTAL_STATES:
+	case PEAK_STATES:
+	case MAX_STATES_PER_INSN:
+	case MARK_READ_MAX_LEN: {
+		long v1 = s1->stats[id];
+		long v2 = s2->stats[id];
+
+		if (v1 != v2)
+			cmp = v1 < v2 ? -1 : 1;
+		break;
+	}
+	default:
+		fprintf(stderr, "Unrecognized stat #%d\n", id);
+		exit(1);
+	}
+
+	return asc ? cmp : -cmp;
+}
+
+static int cmp_prog_stats(const void *v1, const void *v2)
+{
+	const struct verif_stats *s1 = v1, *s2 = v2;
+	int i, cmp;
+
+	for (i = 0; i < env.sort_spec.spec_cnt; i++) {
+		cmp = cmp_stat(s1, s2, env.sort_spec.ids[i], env.sort_spec.asc[i]);
+		if (cmp != 0)
+			return cmp;
+	}
+
+	/* always disambiguate with file+prog, which are unique */
+	cmp = strcmp(s1->file_name, s2->file_name);
+	if (cmp != 0)
+		return cmp;
+	return strcmp(s1->prog_name, s2->prog_name);
+}
+
+static void fetch_join_stat_value(const struct verif_stats_join *s,
+				  enum stat_id id, enum stat_variant var,
+				  const char **str_val,
+				  double *num_val)
+{
+	long v1, v2;
+
+	if (id == FILE_NAME) {
+		*str_val = s->file_name;
+		return;
+	}
+	if (id == PROG_NAME) {
+		*str_val = s->prog_name;
+		return;
+	}
+
+	v1 = s->stats_a ? s->stats_a->stats[id] : 0;
+	v2 = s->stats_b ? s->stats_b->stats[id] : 0;
+
+	switch (var) {
+	case VARIANT_A:
+		if (!s->stats_a)
+			*num_val = -DBL_MAX;
+		else
+			*num_val = s->stats_a->stats[id];
+		return;
+	case VARIANT_B:
+		if (!s->stats_b)
+			*num_val = -DBL_MAX;
+		else
+			*num_val = s->stats_b->stats[id];
+		return;
+	case VARIANT_DIFF:
+		if (!s->stats_a || !s->stats_b)
+			*num_val = -DBL_MAX;
+		else if (id == VERDICT)
+			*num_val = v1 == v2 ? 1.0 /* MATCH */ : 0.0 /* MISMATCH */;
+		else
+			*num_val = (double)(v2 - v1);
+		return;
+	case VARIANT_PCT:
+		if (!s->stats_a || !s->stats_b) {
+			*num_val = -DBL_MAX;
+		} else if (v1 == 0) {
+			if (v1 == v2)
+				*num_val = 0.0;
+			else
+				*num_val = v2 < v1 ? -100.0 : 100.0;
+		} else {
+			 *num_val = (v2 - v1) * 100.0 / v1;
+		}
+		return;
+	}
+}
+
+static int cmp_join_stat(const struct verif_stats_join *s1,
+			 const struct verif_stats_join *s2,
+			 enum stat_id id, enum stat_variant var, bool asc)
+{
+	const char *str1 = NULL, *str2 = NULL;
+	double v1, v2;
+	int cmp = 0;
+
+	fetch_join_stat_value(s1, id, var, &str1, &v1);
+	fetch_join_stat_value(s2, id, var, &str2, &v2);
+
+	if (str1)
+		cmp = strcmp(str1, str2);
+	else if (v1 != v2)
+		cmp = v1 < v2 ? -1 : 1;
+
+	return asc ? cmp : -cmp;
+}
+
+static int cmp_join_stats(const void *v1, const void *v2)
+{
+	const struct verif_stats_join *s1 = v1, *s2 = v2;
+	int i, cmp;
+
+	for (i = 0; i < env.sort_spec.spec_cnt; i++) {
+		cmp = cmp_join_stat(s1, s2,
+				    env.sort_spec.ids[i],
+				    env.sort_spec.variants[i],
+				    env.sort_spec.asc[i]);
+		if (cmp != 0)
+			return cmp;
+	}
+
+	/* always disambiguate with file+prog, which are unique */
+	cmp = strcmp(s1->file_name, s2->file_name);
+	if (cmp != 0)
+		return cmp;
+	return strcmp(s1->prog_name, s2->prog_name);
+}
+
+#define HEADER_CHAR '-'
+#define COLUMN_SEP "  "
+
+static void output_header_underlines(void)
+{
+	int i, j, len;
+
+	for (i = 0; i < env.output_spec.spec_cnt; i++) {
+		len = env.output_spec.lens[i];
+
+		printf("%s", i == 0 ? "" : COLUMN_SEP);
+		for (j = 0; j < len; j++)
+			printf("%c", HEADER_CHAR);
+	}
+	printf("\n");
+}
+
+static void output_headers(enum resfmt fmt)
+{
+	const char *fmt_str;
+	int i, len;
+
+	for (i = 0; i < env.output_spec.spec_cnt; i++) {
+		int id = env.output_spec.ids[i];
+		int *max_len = &env.output_spec.lens[i];
+
+		switch (fmt) {
+		case RESFMT_TABLE_CALCLEN:
+			len = snprintf(NULL, 0, "%s", stat_defs[id].header);
+			if (len > *max_len)
+				*max_len = len;
+			break;
+		case RESFMT_TABLE:
+			fmt_str = stat_defs[id].left_aligned ? "%s%-*s" : "%s%*s";
+			printf(fmt_str, i == 0 ? "" : COLUMN_SEP,  *max_len, stat_defs[id].header);
+			if (i == env.output_spec.spec_cnt - 1)
+				printf("\n");
+			break;
+		case RESFMT_CSV:
+			printf("%s%s", i == 0 ? "" : ",", stat_defs[id].names[0]);
+			if (i == env.output_spec.spec_cnt - 1)
+				printf("\n");
+			break;
+		}
+	}
+
+	if (fmt == RESFMT_TABLE)
+		output_header_underlines();
+}
+
+static void prepare_value(const struct verif_stats *s, enum stat_id id,
+			  const char **str, long *val)
+{
+	switch (id) {
+	case FILE_NAME:
+		*str = s ? s->file_name : "N/A";
+		break;
+	case PROG_NAME:
+		*str = s ? s->prog_name : "N/A";
+		break;
+	case VERDICT:
+		if (!s)
+			*str = "N/A";
+		else
+			*str = s->stats[VERDICT] ? "success" : "failure";
+		break;
+	case DURATION:
+	case TOTAL_INSNS:
+	case TOTAL_STATES:
+	case PEAK_STATES:
+	case MAX_STATES_PER_INSN:
+	case MARK_READ_MAX_LEN:
+		*val = s ? s->stats[id] : 0;
+		break;
+	default:
+		fprintf(stderr, "Unrecognized stat #%d\n", id);
+		exit(1);
+	}
+}
+
+static void output_stats(const struct verif_stats *s, enum resfmt fmt, bool last)
+{
+	int i;
+
+	for (i = 0; i < env.output_spec.spec_cnt; i++) {
+		int id = env.output_spec.ids[i];
+		int *max_len = &env.output_spec.lens[i], len;
+		const char *str = NULL;
+		long val = 0;
+
+		prepare_value(s, id, &str, &val);
+
+		switch (fmt) {
+		case RESFMT_TABLE_CALCLEN:
+			if (str)
+				len = snprintf(NULL, 0, "%s", str);
+			else
+				len = snprintf(NULL, 0, "%ld", val);
+			if (len > *max_len)
+				*max_len = len;
+			break;
+		case RESFMT_TABLE:
+			if (str)
+				printf("%s%-*s", i == 0 ? "" : COLUMN_SEP, *max_len, str);
+			else
+				printf("%s%*ld", i == 0 ? "" : COLUMN_SEP,  *max_len, val);
+			if (i == env.output_spec.spec_cnt - 1)
+				printf("\n");
+			break;
+		case RESFMT_CSV:
+			if (str)
+				printf("%s%s", i == 0 ? "" : ",", str);
+			else
+				printf("%s%ld", i == 0 ? "" : ",", val);
+			if (i == env.output_spec.spec_cnt - 1)
+				printf("\n");
+			break;
+		}
+	}
+
+	if (last && fmt == RESFMT_TABLE) {
+		output_header_underlines();
+		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);
+	}
+}
+
+static int parse_stat_value(const char *str, enum stat_id id, struct verif_stats *st)
+{
+	switch (id) {
+	case FILE_NAME:
+		st->file_name = strdup(str);
+		if (!st->file_name)
+			return -ENOMEM;
+		break;
+	case PROG_NAME:
+		st->prog_name = strdup(str);
+		if (!st->prog_name)
+			return -ENOMEM;
+		break;
+	case VERDICT:
+		if (strcmp(str, "success") == 0) {
+			st->stats[VERDICT] = true;
+		} else if (strcmp(str, "failure") == 0) {
+			st->stats[VERDICT] = false;
+		} else {
+			fprintf(stderr, "Unrecognized verification verdict '%s'\n", str);
+			return -EINVAL;
+		}
+		break;
+	case DURATION:
+	case TOTAL_INSNS:
+	case TOTAL_STATES:
+	case PEAK_STATES:
+	case MAX_STATES_PER_INSN:
+	case MARK_READ_MAX_LEN: {
+		long val;
+		int err, n;
+
+		if (sscanf(str, "%ld %n", &val, &n) != 1 || n != strlen(str)) {
+			err = -errno;
+			fprintf(stderr, "Failed to parse '%s' as integer\n", str);
+			return err;
+		}
+
+		st->stats[id] = val;
+		break;
+	}
+	default:
+		fprintf(stderr, "Unrecognized stat #%d\n", id);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int parse_stats_csv(const char *filename, struct stat_specs *specs,
+			   struct verif_stats **statsp, int *stat_cntp)
+{
+	char line[4096];
+	FILE *f;
+	int err = 0;
+	bool header = true;
+
+	f = fopen(filename, "r");
+	if (!f) {
+		err = -errno;
+		fprintf(stderr, "Failed to open '%s': %d\n", filename, err);
+		return err;
+	}
+
+	*stat_cntp = 0;
+
+	while (fgets(line, sizeof(line), f)) {
+		char *input = line, *state = NULL, *next;
+		struct verif_stats *st = NULL;
+		int col = 0;
+
+		if (!header) {
+			void *tmp;
+
+			tmp = realloc(*statsp, (*stat_cntp + 1) * sizeof(**statsp));
+			if (!tmp) {
+				err = -ENOMEM;
+				goto cleanup;
+			}
+			*statsp = tmp;
+
+			st = &(*statsp)[*stat_cntp];
+			memset(st, 0, sizeof(*st));
+
+			*stat_cntp += 1;
+		}
+
+		while ((next = strtok_r(state ? NULL : input, ",\n", &state))) {
+			if (header) {
+				/* for the first line, set up spec stats */
+				err = parse_stat(next, specs);
+				if (err)
+					goto cleanup;
+				continue;
+			}
+
+			/* for all other lines, parse values based on spec */
+			if (col >= specs->spec_cnt) {
+				fprintf(stderr, "Found extraneous column #%d in row #%d of '%s'\n",
+					col, *stat_cntp, filename);
+				err = -EINVAL;
+				goto cleanup;
+			}
+			err = parse_stat_value(next, specs->ids[col], st);
+			if (err)
+				goto cleanup;
+			col++;
+		}
+
+		if (header) {
+			header = false;
+			continue;
+		}
+
+		if (col < specs->spec_cnt) {
+			fprintf(stderr, "Not enough columns in row #%d in '%s'\n",
+				*stat_cntp, filename);
+			err = -EINVAL;
+			goto cleanup;
+		}
+
+		if (!st->file_name || !st->prog_name) {
+			fprintf(stderr, "Row #%d in '%s' is missing file and/or program name\n",
+				*stat_cntp, filename);
+			err = -EINVAL;
+			goto cleanup;
+		}
+
+		/* in comparison mode we can only check filters after we
+		 * parsed entire line; if row should be ignored we pretend we
+		 * never parsed it
+		 */
+		if (!should_process_file_prog(st->file_name, st->prog_name)) {
+			free(st->file_name);
+			free(st->prog_name);
+			*stat_cntp -= 1;
+		}
+	}
+
+	if (!feof(f)) {
+		err = -errno;
+		fprintf(stderr, "Failed I/O for '%s': %d\n", filename, err);
+	}
+
+cleanup:
+	fclose(f);
+	return err;
+}
+
+/* empty/zero stats for mismatched rows */
+static const struct verif_stats fallback_stats = { .file_name = "", .prog_name = "" };
+
+static bool is_key_stat(enum stat_id id)
+{
+	return id == FILE_NAME || id == PROG_NAME;
+}
+
+static void output_comp_header_underlines(void)
+{
+	int i, j, k;
+
+	for (i = 0; i < env.output_spec.spec_cnt; i++) {
+		int id = env.output_spec.ids[i];
+		int max_j = is_key_stat(id) ? 1 : 3;
+
+		for (j = 0; j < max_j; j++) {
+			int len = env.output_spec.lens[3 * i + j];
+
+			printf("%s", i + j == 0 ? "" : COLUMN_SEP);
+
+			for (k = 0; k < len; k++)
+				printf("%c", HEADER_CHAR);
+		}
+	}
+	printf("\n");
+}
+
+static void output_comp_headers(enum resfmt fmt)
+{
+	static const char *table_sfxs[3] = {" (A)", " (B)", " (DIFF)"};
+	static const char *name_sfxs[3] = {"_base", "_comp", "_diff"};
+	int i, j, len;
+
+	for (i = 0; i < env.output_spec.spec_cnt; i++) {
+		int id = env.output_spec.ids[i];
+		/* key stats don't have A/B/DIFF columns, they are common for both data sets */
+		int max_j = is_key_stat(id) ? 1 : 3;
+
+		for (j = 0; j < max_j; j++) {
+			int *max_len = &env.output_spec.lens[3 * i + j];
+			bool last = (i == env.output_spec.spec_cnt - 1) && (j == max_j - 1);
+			const char *sfx;
+
+			switch (fmt) {
+			case RESFMT_TABLE_CALCLEN:
+				sfx = is_key_stat(id) ? "" : table_sfxs[j];
+				len = snprintf(NULL, 0, "%s%s", stat_defs[id].header, sfx);
+				if (len > *max_len)
+					*max_len = len;
+				break;
+			case RESFMT_TABLE:
+				sfx = is_key_stat(id) ? "" : table_sfxs[j];
+				printf("%s%-*s%s", i + j == 0 ? "" : COLUMN_SEP,
+				       *max_len - (int)strlen(sfx), stat_defs[id].header, sfx);
+				if (last)
+					printf("\n");
+				break;
+			case RESFMT_CSV:
+				sfx = is_key_stat(id) ? "" : name_sfxs[j];
+				printf("%s%s%s", i + j == 0 ? "" : ",", stat_defs[id].names[0], sfx);
+				if (last)
+					printf("\n");
+				break;
+			}
+		}
+	}
+
+	if (fmt == RESFMT_TABLE)
+		output_comp_header_underlines();
+}
+
+static void output_comp_stats(const struct verif_stats_join *join_stats,
+			      enum resfmt fmt, bool last)
+{
+	const struct verif_stats *base = join_stats->stats_a;
+	const struct verif_stats *comp = join_stats->stats_b;
+	char base_buf[1024] = {}, comp_buf[1024] = {}, diff_buf[1024] = {};
+	int i;
+
+	for (i = 0; i < env.output_spec.spec_cnt; i++) {
+		int id = env.output_spec.ids[i], len;
+		int *max_len_base = &env.output_spec.lens[3 * i + 0];
+		int *max_len_comp = &env.output_spec.lens[3 * i + 1];
+		int *max_len_diff = &env.output_spec.lens[3 * i + 2];
+		const char *base_str = NULL, *comp_str = NULL;
+		long base_val = 0, comp_val = 0, diff_val = 0;
+
+		prepare_value(base, id, &base_str, &base_val);
+		prepare_value(comp, id, &comp_str, &comp_val);
+
+		/* normalize all the outputs to be in string buffers for simplicity */
+		if (is_key_stat(id)) {
+			/* key stats (file and program name) are always strings */
+			if (base)
+				snprintf(base_buf, sizeof(base_buf), "%s", base_str);
+			else
+				snprintf(base_buf, sizeof(base_buf), "%s", comp_str);
+		} else if (base_str) {
+			snprintf(base_buf, sizeof(base_buf), "%s", base_str);
+			snprintf(comp_buf, sizeof(comp_buf), "%s", comp_str);
+			if (!base || !comp)
+				snprintf(diff_buf, sizeof(diff_buf), "%s", "N/A");
+			else if (strcmp(base_str, comp_str) == 0)
+				snprintf(diff_buf, sizeof(diff_buf), "%s", "MATCH");
+			else
+				snprintf(diff_buf, sizeof(diff_buf), "%s", "MISMATCH");
+		} else {
+			double p = 0.0;
+
+			if (base)
+				snprintf(base_buf, sizeof(base_buf), "%ld", base_val);
+			else
+				snprintf(base_buf, sizeof(base_buf), "%s", "N/A");
+			if (comp)
+				snprintf(comp_buf, sizeof(comp_buf), "%ld", comp_val);
+			else
+				snprintf(comp_buf, sizeof(comp_buf), "%s", "N/A");
+
+			diff_val = comp_val - base_val;
+			if (!base || !comp) {
+				snprintf(diff_buf, sizeof(diff_buf), "%s", "N/A");
+			} else {
+				if (base_val == 0) {
+					if (comp_val == base_val)
+						p = 0.0; /* avoid +0 (+100%) case */
+					else
+						p = comp_val < base_val ? -100.0 : 100.0;
+				} else {
+					 p = diff_val * 100.0 / base_val;
+				}
+				snprintf(diff_buf, sizeof(diff_buf), "%+ld (%+.2lf%%)", diff_val, p);
+			}
+		}
+
+		switch (fmt) {
+		case RESFMT_TABLE_CALCLEN:
+			len = strlen(base_buf);
+			if (len > *max_len_base)
+				*max_len_base = len;
+			if (!is_key_stat(id)) {
+				len = strlen(comp_buf);
+				if (len > *max_len_comp)
+					*max_len_comp = len;
+				len = strlen(diff_buf);
+				if (len > *max_len_diff)
+					*max_len_diff = len;
+			}
+			break;
+		case RESFMT_TABLE: {
+			/* string outputs are left-aligned, number outputs are right-aligned */
+			const char *fmt = base_str ? "%s%-*s" : "%s%*s";
+
+			printf(fmt, i == 0 ? "" : COLUMN_SEP, *max_len_base, base_buf);
+			if (!is_key_stat(id)) {
+				printf(fmt, COLUMN_SEP, *max_len_comp, comp_buf);
+				printf(fmt, COLUMN_SEP, *max_len_diff, diff_buf);
+			}
+			if (i == env.output_spec.spec_cnt - 1)
+				printf("\n");
+			break;
+		}
+		case RESFMT_CSV:
+			printf("%s%s", i == 0 ? "" : ",", base_buf);
+			if (!is_key_stat(id)) {
+				printf("%s%s", i == 0 ? "" : ",", comp_buf);
+				printf("%s%s", i == 0 ? "" : ",", diff_buf);
+			}
+			if (i == env.output_spec.spec_cnt - 1)
+				printf("\n");
+			break;
+		}
+	}
+
+	if (last && fmt == RESFMT_TABLE)
+		output_comp_header_underlines();
+}
+
+static int cmp_stats_key(const struct verif_stats *base, const struct verif_stats *comp)
+{
+	int r;
+
+	r = strcmp(base->file_name, comp->file_name);
+	if (r != 0)
+		return r;
+	return strcmp(base->prog_name, comp->prog_name);
+}
+
+static bool is_join_stat_filter_matched(struct filter *f, const struct verif_stats_join *stats)
+{
+	static const double eps = 1e-9;
+	const char *str = NULL;
+	double value = 0.0;
+
+	fetch_join_stat_value(stats, f->stat_id, f->stat_var, &str, &value);
+
+	switch (f->op) {
+	case OP_EQ: return value > f->value - eps && value < f->value + eps;
+	case OP_NEQ: return value < f->value - eps || value > f->value + eps;
+	case OP_LT: return value < f->value - eps;
+	case OP_LE: return value <= f->value + eps;
+	case OP_GT: return value > f->value + eps;
+	case OP_GE: return value >= f->value - eps;
+	}
+
+	fprintf(stderr, "BUG: unknown filter op %d!\n", f->op);
+	return false;
+}
+
+static bool should_output_join_stats(const struct verif_stats_join *stats)
+{
+	struct filter *f;
+	int i, allow_cnt = 0;
+
+	for (i = 0; i < env.deny_filter_cnt; i++) {
+		f = &env.deny_filters[i];
+		if (f->kind != FILTER_STAT)
+			continue;
+
+		if (is_join_stat_filter_matched(f, stats))
+			return false;
+	}
+
+	for (i = 0; i < env.allow_filter_cnt; i++) {
+		f = &env.allow_filters[i];
+		if (f->kind != FILTER_STAT)
+			continue;
+		allow_cnt++;
+
+		if (is_join_stat_filter_matched(f, stats))
+			return true;
+	}
+
+	/* if there are no stat allowed filters, pass everything through */
+	return allow_cnt == 0;
+}
+
+static int handle_comparison_mode(void)
+{
+	struct stat_specs base_specs = {}, comp_specs = {};
+	struct stat_specs tmp_sort_spec;
+	enum resfmt cur_fmt;
+	int err, i, j, last_idx;
+
+	if (env.filename_cnt != 2) {
+		fprintf(stderr, "Comparison mode expects exactly two input CSV files!\n\n");
+		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
+		return -EINVAL;
+	}
+
+	err = parse_stats_csv(env.filenames[0], &base_specs,
+			      &env.baseline_stats, &env.baseline_stat_cnt);
+	if (err) {
+		fprintf(stderr, "Failed to parse stats from '%s': %d\n", env.filenames[0], err);
+		return err;
+	}
+	err = parse_stats_csv(env.filenames[1], &comp_specs,
+			      &env.prog_stats, &env.prog_stat_cnt);
+	if (err) {
+		fprintf(stderr, "Failed to parse stats from '%s': %d\n", env.filenames[1], err);
+		return err;
+	}
+
+	/* To keep it simple we validate that the set and order of stats in
+	 * both CSVs are exactly the same. This can be lifted with a bit more
+	 * pre-processing later.
+	 */
+	if (base_specs.spec_cnt != comp_specs.spec_cnt) {
+		fprintf(stderr, "Number of stats in '%s' and '%s' differs (%d != %d)!\n",
+			env.filenames[0], env.filenames[1],
+			base_specs.spec_cnt, comp_specs.spec_cnt);
+		return -EINVAL;
+	}
+	for (i = 0; i < base_specs.spec_cnt; i++) {
+		if (base_specs.ids[i] != comp_specs.ids[i]) {
+			fprintf(stderr, "Stats composition differs between '%s' and '%s' (%s != %s)!\n",
+				env.filenames[0], env.filenames[1],
+				stat_defs[base_specs.ids[i]].names[0],
+				stat_defs[comp_specs.ids[i]].names[0]);
+			return -EINVAL;
+		}
+	}
+
+	/* Replace user-specified sorting spec with file+prog sorting rule to
+	 * be able to join two datasets correctly. Once we are done, we will
+	 * restore the original sort spec.
+	 */
+	tmp_sort_spec = env.sort_spec;
+	env.sort_spec = join_sort_spec;
+	qsort(env.prog_stats, env.prog_stat_cnt, sizeof(*env.prog_stats), cmp_prog_stats);
+	qsort(env.baseline_stats, env.baseline_stat_cnt, sizeof(*env.baseline_stats), cmp_prog_stats);
+	env.sort_spec = tmp_sort_spec;
+
+	/* Join two datasets together. If baseline and comparison datasets
+	 * have different subset of rows (we match by 'object + prog' as
+	 * a unique key) then assume empty/missing/zero value for rows that
+	 * are missing in the opposite data set.
+	 */
+	i = j = 0;
+	while (i < env.baseline_stat_cnt || j < env.prog_stat_cnt) {
+		const struct verif_stats *base, *comp;
+		struct verif_stats_join *join;
+		void *tmp;
+		int r;
+
+		base = i < env.baseline_stat_cnt ? &env.baseline_stats[i] : &fallback_stats;
+		comp = j < env.prog_stat_cnt ? &env.prog_stats[j] : &fallback_stats;
+
+		if (!base->file_name || !base->prog_name) {
+			fprintf(stderr, "Entry #%d in '%s' doesn't have file and/or program name specified!\n",
+				i, env.filenames[0]);
+			return -EINVAL;
+		}
+		if (!comp->file_name || !comp->prog_name) {
+			fprintf(stderr, "Entry #%d in '%s' doesn't have file and/or program name specified!\n",
+				j, env.filenames[1]);
+			return -EINVAL;
+		}
+
+		tmp = realloc(env.join_stats, (env.join_stat_cnt + 1) * sizeof(*env.join_stats));
+		if (!tmp)
+			return -ENOMEM;
+		env.join_stats = tmp;
+
+		join = &env.join_stats[env.join_stat_cnt];
+		memset(join, 0, sizeof(*join));
+
+		r = cmp_stats_key(base, comp);
+		if (r == 0) {
+			join->file_name = base->file_name;
+			join->prog_name = base->prog_name;
+			join->stats_a = base;
+			join->stats_b = comp;
+			i++;
+			j++;
+		} else if (base != &fallback_stats && (comp == &fallback_stats || r < 0)) {
+			join->file_name = base->file_name;
+			join->prog_name = base->prog_name;
+			join->stats_a = base;
+			join->stats_b = NULL;
+			i++;
+		} else if (comp != &fallback_stats && (base == &fallback_stats || r > 0)) {
+			join->file_name = comp->file_name;
+			join->prog_name = comp->prog_name;
+			join->stats_a = NULL;
+			join->stats_b = comp;
+			j++;
+		} else {
+			fprintf(stderr, "%s:%d: should never reach here i=%i, j=%i",
+				__FILE__, __LINE__, i, j);
+			return -EINVAL;
+		}
+		env.join_stat_cnt += 1;
+	}
+
+	/* now sort joined results accorsing to sort spec */
+	qsort(env.join_stats, env.join_stat_cnt, sizeof(*env.join_stats), cmp_join_stats);
+
+	/* for human-readable table output we need to do extra pass to
+	 * calculate column widths, so we substitute current output format
+	 * with RESFMT_TABLE_CALCLEN and later revert it back to RESFMT_TABLE
+	 * and do everything again.
+	 */
+	if (env.out_fmt == RESFMT_TABLE)
+		cur_fmt = RESFMT_TABLE_CALCLEN;
+	else
+		cur_fmt = env.out_fmt;
+
+one_more_time:
+	output_comp_headers(cur_fmt);
+
+	last_idx = -1;
+	for (i = 0; i < env.join_stat_cnt; i++) {
+		const struct verif_stats_join *join = &env.join_stats[i];
+
+		if (!should_output_join_stats(join))
+			continue;
+
+		if (cur_fmt == RESFMT_TABLE_CALCLEN)
+			last_idx = i;
+
+		output_comp_stats(join, cur_fmt, i == last_idx);
+	}
+
+	if (cur_fmt == RESFMT_TABLE_CALCLEN) {
+		cur_fmt = RESFMT_TABLE;
+		goto one_more_time; /* ... this time with feeling */
+	}
+
+	return 0;
+}
+
+static bool is_stat_filter_matched(struct filter *f, const struct verif_stats *stats)
+{
+	long value = stats->stats[f->stat_id];
+
+	switch (f->op) {
+	case OP_EQ: return value == f->value;
+	case OP_NEQ: return value != f->value;
+	case OP_LT: return value < f->value;
+	case OP_LE: return value <= f->value;
+	case OP_GT: return value > f->value;
+	case OP_GE: return value >= f->value;
+	}
+
+	fprintf(stderr, "BUG: unknown filter op %d!\n", f->op);
+	return false;
+}
+
+static bool should_output_stats(const struct verif_stats *stats)
+{
+	struct filter *f;
+	int i, allow_cnt = 0;
+
+	for (i = 0; i < env.deny_filter_cnt; i++) {
+		f = &env.deny_filters[i];
+		if (f->kind != FILTER_STAT)
+			continue;
+
+		if (is_stat_filter_matched(f, stats))
+			return false;
+	}
+
+	for (i = 0; i < env.allow_filter_cnt; i++) {
+		f = &env.allow_filters[i];
+		if (f->kind != FILTER_STAT)
+			continue;
+		allow_cnt++;
+
+		if (is_stat_filter_matched(f, stats))
+			return true;
+	}
+
+	/* if there are no stat allowed filters, pass everything through */
+	return allow_cnt == 0;
+}
+
+static void output_prog_stats(void)
+{
+	const struct verif_stats *stats;
+	int i, last_stat_idx = 0;
+
+	if (env.out_fmt == RESFMT_TABLE) {
+		/* calculate column widths */
+		output_headers(RESFMT_TABLE_CALCLEN);
+		for (i = 0; i < env.prog_stat_cnt; i++) {
+			stats = &env.prog_stats[i];
+			if (!should_output_stats(stats))
+				continue;
+			output_stats(stats, RESFMT_TABLE_CALCLEN, false);
+			last_stat_idx = i;
+		}
+	}
+
+	/* actually output the table */
+	output_headers(env.out_fmt);
+	for (i = 0; i < env.prog_stat_cnt; i++) {
+		stats = &env.prog_stats[i];
+		if (!should_output_stats(stats))
+			continue;
+		output_stats(stats, env.out_fmt, i == last_stat_idx);
+	}
+}
+
+static int handle_verif_mode(void)
+{
+	int i, err;
+
+	if (env.filename_cnt == 0) {
+		fprintf(stderr, "Please provide path to BPF object file!\n\n");
+		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < env.filename_cnt; i++) {
+		err = process_obj(env.filenames[i]);
+		if (err) {
+			fprintf(stderr, "Failed to process '%s': %d\n", env.filenames[i], err);
+			return err;
+		}
+	}
+
+	qsort(env.prog_stats, env.prog_stat_cnt, sizeof(*env.prog_stats), cmp_prog_stats);
+
+	output_prog_stats();
+
+	return 0;
+}
+
+static int handle_replay_mode(void)
+{
+	struct stat_specs specs = {};
+	int err;
+
+	if (env.filename_cnt != 1) {
+		fprintf(stderr, "Replay mode expects exactly one input CSV file!\n\n");
+		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
+		return -EINVAL;
+	}
+
+	err = parse_stats_csv(env.filenames[0], &specs,
+			      &env.prog_stats, &env.prog_stat_cnt);
+	if (err) {
+		fprintf(stderr, "Failed to parse stats from '%s': %d\n", env.filenames[0], err);
+		return err;
+	}
+
+	qsort(env.prog_stats, env.prog_stat_cnt, sizeof(*env.prog_stats), cmp_prog_stats);
+
+	output_prog_stats();
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	int err = 0, i;
+
+	if (argp_parse(&argp, argc, argv, 0, NULL, NULL))
+		return 1;
+
+	if (env.show_version) {
+		printf("%s\n", argp_program_version);
+		return 0;
+	}
+
+	if (env.verbose && env.quiet) {
+		fprintf(stderr, "Verbose and quiet modes are incompatible, please specify just one or neither!\n\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) {
+		if (env.out_fmt == RESFMT_CSV)
+			env.output_spec = default_csv_output_spec;
+		else
+			env.output_spec = default_output_spec;
+	}
+	if (env.sort_spec.spec_cnt == 0)
+		env.sort_spec = default_sort_spec;
+
+	if (env.comparison_mode && env.replay_mode) {
+		fprintf(stderr, "Can't specify replay and comparison mode at the same time!\n\n");
+		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
+		return 1;
+	}
+
+	if (env.comparison_mode)
+		err = handle_comparison_mode();
+	else if (env.replay_mode)
+		err = handle_replay_mode();
+	else
+		err = handle_verif_mode();
+
+	free_verif_stats(env.prog_stats, env.prog_stat_cnt);
+	free_verif_stats(env.baseline_stats, env.baseline_stat_cnt);
+	free(env.join_stats);
+	for (i = 0; i < env.filename_cnt; i++)
+		free(env.filenames[i]);
+	free(env.filenames);
+	for (i = 0; i < env.allow_filter_cnt; i++) {
+		free(env.allow_filters[i].any_glob);
+		free(env.allow_filters[i].file_glob);
+		free(env.allow_filters[i].prog_glob);
+	}
+	free(env.allow_filters);
+	for (i = 0; i < env.deny_filter_cnt; i++) {
+		free(env.deny_filters[i].any_glob);
+		free(env.deny_filters[i].file_glob);
+		free(env.deny_filters[i].prog_glob);
+	}
+	free(env.deny_filters);
+	return -err;
+}