linux/tools/bpf/bpftool/main.c

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2017-2018 Netronome Systems, Inc. */

#include <ctype.h>
#include <errno.h>
#include <getopt.h>
#include <linux/bpf.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <bpf/bpf.h>
#include <bpf/btf.h>
#include <bpf/hashmap.h>
#include <bpf/libbpf.h>

#include "main.h"

#define BATCH_LINE_LEN_MAX 65536
#define BATCH_ARG_NB_MAX 4096

const char *bin_name;
static int last_argc;
static char **last_argv;
static int (*last_do_help)(int argc, char **argv);
json_writer_t *json_wtr;
bool pretty_output;
bool json_output;
bool show_pinned;
bool block_mount;
bool verifier_logs;
bool relaxed_maps;
bool use_loader;
struct btf *base_btf;
struct hashmap *refs_table;

static void __noreturn clean_and_exit(int i)
{
	if (json_output)
		jsonw_destroy(&json_wtr);

	exit(i);
}

void usage(void)
{
	last_do_help(last_argc - 1, last_argv + 1);

	clean_and_exit(-1);
}

static int do_help(int argc, char **argv)
{
	if (json_output) {
		jsonw_null(json_wtr);
		return 0;
	}

	fprintf(stderr,
		"Usage: %s [OPTIONS] OBJECT { COMMAND | help }\n"
		"       %s batch file FILE\n"
		"       %s version\n"
		"\n"
		"       OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter }\n"
		"       " HELP_SPEC_OPTIONS " |\n"
		"                    {-V|--version} }\n"
		"",
		bin_name, bin_name, bin_name);

	return 0;
}

static int do_batch(int argc, char **argv);
static int do_version(int argc, char **argv);

static const struct cmd commands[] = {
	{ "help",	do_help },
	{ "batch",	do_batch },
	{ "prog",	do_prog },
	{ "map",	do_map },
	{ "link",	do_link },
	{ "cgroup",	do_cgroup },
	{ "perf",	do_perf },
	{ "net",	do_net },
	{ "feature",	do_feature },
	{ "btf",	do_btf },
	{ "gen",	do_gen },
	{ "struct_ops",	do_struct_ops },
	{ "iter",	do_iter },
	{ "version",	do_version },
	{ 0 }
};

#ifndef BPFTOOL_VERSION
/* bpftool's major and minor version numbers are aligned on libbpf's. There is
 * an offset of 6 for the version number, because bpftool's version was higher
 * than libbpf's when we adopted this scheme. The patch number remains at 0
 * for now. Set BPFTOOL_VERSION to override.
 */
#define BPFTOOL_MAJOR_VERSION (LIBBPF_MAJOR_VERSION + 6)
#define BPFTOOL_MINOR_VERSION LIBBPF_MINOR_VERSION
#define BPFTOOL_PATCH_VERSION 0
#endif

static void
print_feature(const char *feature, bool state, unsigned int *nb_features)
{
	if (state) {
		printf("%s %s", *nb_features ? "," : "", feature);
		*nb_features = *nb_features + 1;
	}
}

static int do_version(int argc, char **argv)
{
#ifdef HAVE_LIBBFD_SUPPORT
	const bool has_libbfd = true;
#else
	const bool has_libbfd = false;
#endif
#ifdef HAVE_LLVM_SUPPORT
	const bool has_llvm = true;
#else
	const bool has_llvm = false;
#endif
#ifdef BPFTOOL_WITHOUT_SKELETONS
	const bool has_skeletons = false;
#else
	const bool has_skeletons = true;
#endif
	bool bootstrap = false;
	int i;

	for (i = 0; commands[i].cmd; i++) {
		if (!strcmp(commands[i].cmd, "prog")) {
			/* Assume we run a bootstrap version if "bpftool prog"
			 * is not available.
			 */
			bootstrap = !commands[i].func;
			break;
		}
	}

	if (json_output) {
		jsonw_start_object(json_wtr);	/* root object */

		jsonw_name(json_wtr, "version");
#ifdef BPFTOOL_VERSION
		jsonw_printf(json_wtr, "\"%s\"", BPFTOOL_VERSION);
#else
		jsonw_printf(json_wtr, "\"%d.%d.%d\"", BPFTOOL_MAJOR_VERSION,
			     BPFTOOL_MINOR_VERSION, BPFTOOL_PATCH_VERSION);
#endif
		jsonw_name(json_wtr, "libbpf_version");
		jsonw_printf(json_wtr, "\"%u.%u\"",
			     libbpf_major_version(), libbpf_minor_version());

		jsonw_name(json_wtr, "features");
		jsonw_start_object(json_wtr);	/* features */
		jsonw_bool_field(json_wtr, "libbfd", has_libbfd);
		jsonw_bool_field(json_wtr, "llvm", has_llvm);
		jsonw_bool_field(json_wtr, "skeletons", has_skeletons);
		jsonw_bool_field(json_wtr, "bootstrap", bootstrap);
		jsonw_end_object(json_wtr);	/* features */

		jsonw_end_object(json_wtr);	/* root object */
	} else {
		unsigned int nb_features = 0;

#ifdef BPFTOOL_VERSION
		printf("%s v%s\n", bin_name, BPFTOOL_VERSION);
#else
		printf("%s v%d.%d.%d\n", bin_name, BPFTOOL_MAJOR_VERSION,
		       BPFTOOL_MINOR_VERSION, BPFTOOL_PATCH_VERSION);
#endif
		printf("using libbpf %s\n", libbpf_version_string());
		printf("features:");
		print_feature("libbfd", has_libbfd, &nb_features);
		print_feature("llvm", has_llvm, &nb_features);
		print_feature("skeletons", has_skeletons, &nb_features);
		print_feature("bootstrap", bootstrap, &nb_features);
		printf("\n");
	}
	return 0;
}

int cmd_select(const struct cmd *cmds, int argc, char **argv,
	       int (*help)(int argc, char **argv))
{
	unsigned int i;

	last_argc = argc;
	last_argv = argv;
	last_do_help = help;

	if (argc < 1 && cmds[0].func)
		return cmds[0].func(argc, argv);

	for (i = 0; cmds[i].cmd; i++) {
		if (is_prefix(*argv, cmds[i].cmd)) {
			if (!cmds[i].func) {
				p_err("command '%s' is not supported in bootstrap mode",
				      cmds[i].cmd);
				return -1;
			}
			return cmds[i].func(argc - 1, argv + 1);
		}
	}

	help(argc - 1, argv + 1);

	return -1;
}

bool is_prefix(const char *pfx, const char *str)
{
	if (!pfx)
		return false;
	if (strlen(str) < strlen(pfx))
		return false;

	return !memcmp(str, pfx, strlen(pfx));
}

/* Last argument MUST be NULL pointer */
int detect_common_prefix(const char *arg, ...)
{
	unsigned int count = 0;
	const char *ref;
	char msg[256];
	va_list ap;

	snprintf(msg, sizeof(msg), "ambiguous prefix: '%s' could be '", arg);
	va_start(ap, arg);
	while ((ref = va_arg(ap, const char *))) {
		if (!is_prefix(arg, ref))
			continue;
		count++;
		if (count > 1)
			strncat(msg, "' or '", sizeof(msg) - strlen(msg) - 1);
		strncat(msg, ref, sizeof(msg) - strlen(msg) - 1);
	}
	va_end(ap);
	strncat(msg, "'", sizeof(msg) - strlen(msg) - 1);

	if (count >= 2) {
		p_err("%s", msg);
		return -1;
	}

	return 0;
}

void fprint_hex(FILE *f, void *arg, unsigned int n, const char *sep)
{
	unsigned char *data = arg;
	unsigned int i;

	for (i = 0; i < n; i++) {
		const char *pfx = "";

		if (!i)
			/* nothing */;
		else if (!(i % 16))
			fprintf(f, "\n");
		else if (!(i % 8))
			fprintf(f, "  ");
		else
			pfx = sep;

		fprintf(f, "%s%02hhx", i ? pfx : "", data[i]);
	}
}

/* Split command line into argument vector. */
static int make_args(char *line, char *n_argv[], int maxargs, int cmd_nb)
{
	static const char ws[] = " \t\r\n";
	char *cp = line;
	int n_argc = 0;

	while (*cp) {
		/* Skip leading whitespace. */
		cp += strspn(cp, ws);

		if (*cp == '\0')
			break;

		if (n_argc >= (maxargs - 1)) {
			p_err("too many arguments to command %d", cmd_nb);
			return -1;
		}

		/* Word begins with quote. */
		if (*cp == '\'' || *cp == '"') {
			char quote = *cp++;

			n_argv[n_argc++] = cp;
			/* Find ending quote. */
			cp = strchr(cp, quote);
			if (!cp) {
				p_err("unterminated quoted string in command %d",
				      cmd_nb);
				return -1;
			}
		} else {
			n_argv[n_argc++] = cp;

			/* Find end of word. */
			cp += strcspn(cp, ws);
			if (*cp == '\0')
				break;
		}

		/* Separate words. */
		*cp++ = 0;
	}
	n_argv[n_argc] = NULL;

	return n_argc;
}

static int do_batch(int argc, char **argv)
{
	char buf[BATCH_LINE_LEN_MAX], contline[BATCH_LINE_LEN_MAX];
	char *n_argv[BATCH_ARG_NB_MAX];
	unsigned int lines = 0;
	int n_argc;
	FILE *fp;
	char *cp;
	int err = 0;
	int i;

	if (argc < 2) {
		p_err("too few parameters for batch");
		return -1;
	} else if (argc > 2) {
		p_err("too many parameters for batch");
		return -1;
	} else if (!is_prefix(*argv, "file")) {
		p_err("expected 'file', got: %s", *argv);
		return -1;
	}
	NEXT_ARG();

	if (!strcmp(*argv, "-"))
		fp = stdin;
	else
		fp = fopen(*argv, "r");
	if (!fp) {
		p_err("Can't open file (%s): %s", *argv, strerror(errno));
		return -1;
	}

	if (json_output)
		jsonw_start_array(json_wtr);
	while (fgets(buf, sizeof(buf), fp)) {
		cp = strchr(buf, '#');
		if (cp)
			*cp = '\0';

		if (strlen(buf) == sizeof(buf) - 1) {
			errno = E2BIG;
			break;
		}

		/* Append continuation lines if any (coming after a line ending
		 * with '\' in the batch file).
		 */
		while ((cp = strstr(buf, "\\\n")) != NULL) {
			if (!fgets(contline, sizeof(contline), fp) ||
			    strlen(contline) == 0) {
				p_err("missing continuation line on command %u",
				      lines);
				err = -1;
				goto err_close;
			}

			cp = strchr(contline, '#');
			if (cp)
				*cp = '\0';

			if (strlen(buf) + strlen(contline) + 1 > sizeof(buf)) {
				p_err("command %u is too long", lines);
				err = -1;
				goto err_close;
			}
			buf[strlen(buf) - 2] = '\0';
			strcat(buf, contline);
		}

		n_argc = make_args(buf, n_argv, BATCH_ARG_NB_MAX, lines);
		if (!n_argc)
			continue;
		if (n_argc < 0) {
			err = n_argc;
			goto err_close;
		}

		if (json_output) {
			jsonw_start_object(json_wtr);
			jsonw_name(json_wtr, "command");
			jsonw_start_array(json_wtr);
			for (i = 0; i < n_argc; i++)
				jsonw_string(json_wtr, n_argv[i]);
			jsonw_end_array(json_wtr);
			jsonw_name(json_wtr, "output");
		}

		err = cmd_select(commands, n_argc, n_argv, do_help);

		if (json_output)
			jsonw_end_object(json_wtr);

		if (err)
			goto err_close;

		lines++;
	}

	if (errno && errno != ENOENT) {
		p_err("reading batch file failed: %s", strerror(errno));
		err = -1;
	} else {
		if (!json_output)
			printf("processed %u commands\n", lines);
	}
err_close:
	if (fp != stdin)
		fclose(fp);

	if (json_output)
		jsonw_end_array(json_wtr);

	return err;
}

int main(int argc, char **argv)
{
	static const struct option options[] = {
		{ "json",	no_argument,	NULL,	'j' },
		{ "help",	no_argument,	NULL,	'h' },
		{ "pretty",	no_argument,	NULL,	'p' },
		{ "version",	no_argument,	NULL,	'V' },
		{ "bpffs",	no_argument,	NULL,	'f' },
		{ "mapcompat",	no_argument,	NULL,	'm' },
		{ "nomount",	no_argument,	NULL,	'n' },
		{ "debug",	no_argument,	NULL,	'd' },
		{ "use-loader",	no_argument,	NULL,	'L' },
		{ "base-btf",	required_argument, NULL, 'B' },
		{ 0 }
	};
	bool version_requested = false;
	int opt, ret;

	setlinebuf(stdout);

#ifdef USE_LIBCAP
	/* Libcap < 2.63 hooks before main() to compute the number of
	 * capabilities of the running kernel, and doing so it calls prctl()
	 * which may fail and set errno to non-zero.
	 * Let's reset errno to make sure this does not interfere with the
	 * batch mode.
	 */
	errno = 0;
#endif

	last_do_help = do_help;
	pretty_output = false;
	json_output = false;
	show_pinned = false;
	block_mount = false;
	bin_name = "bpftool";

	opterr = 0;
	while ((opt = getopt_long(argc, argv, "VhpjfLmndB:l",
				  options, NULL)) >= 0) {
		switch (opt) {
		case 'V':
			version_requested = true;
			break;
		case 'h':
			return do_help(argc, argv);
		case 'p':
			pretty_output = true;
			/* fall through */
		case 'j':
			if (!json_output) {
				json_wtr = jsonw_new(stdout);
				if (!json_wtr) {
					p_err("failed to create JSON writer");
					return -1;
				}
				json_output = true;
			}
			jsonw_pretty(json_wtr, pretty_output);
			break;
		case 'f':
			show_pinned = true;
			break;
		case 'm':
			relaxed_maps = true;
			break;
		case 'n':
			block_mount = true;
			break;
		case 'd':
			libbpf_set_print(print_all_levels);
			verifier_logs = true;
			break;
		case 'B':
			base_btf = btf__parse(optarg, NULL);
			if (!base_btf) {
				p_err("failed to parse base BTF at '%s': %d\n",
				      optarg, -errno);
				return -1;
			}
			break;
		case 'L':
			use_loader = true;
			break;
		default:
			p_err("unrecognized option '%s'", argv[optind - 1]);
			if (json_output)
				clean_and_exit(-1);
			else
				usage();
		}
	}

	argc -= optind;
	argv += optind;
	if (argc < 0)
		usage();

	if (version_requested)
		return do_version(argc, argv);

	ret = cmd_select(commands, argc, argv, do_help);

	if (json_output)
		jsonw_destroy(&json_wtr);

	btf__free(base_btf);

	return ret;
}