xref: /linux/tools/bpf/bpftool/main.c (revision 9e56ff53b4115875667760445b028357848b4748) 
1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2017-2018 Netronome Systems, Inc. */
3 
4 #include <ctype.h>
5 #include <errno.h>
6 #include <getopt.h>
7 #include <linux/bpf.h>
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <string.h>
11 
12 #include <bpf/bpf.h>
13 #include <bpf/btf.h>
14 #include <bpf/hashmap.h>
15 #include <bpf/libbpf.h>
16 
17 #include "main.h"
18 
19 #define BATCH_LINE_LEN_MAX 65536
20 #define BATCH_ARG_NB_MAX 4096
21 
22 const char *bin_name;
23 static int last_argc;
24 static char **last_argv;
25 static int (*last_do_help)(int argc, char **argv);
26 json_writer_t *json_wtr;
27 bool pretty_output;
28 bool json_output;
29 bool show_pinned;
30 bool block_mount;
31 bool verifier_logs;
32 bool relaxed_maps;
33 bool use_loader;
34 struct btf *base_btf;
35 struct hashmap *refs_table;
36 
37 static void __noreturn clean_and_exit(int i)
38 {
39 	if (json_output)
40 		jsonw_destroy(&json_wtr);
41 
42 	exit(i);
43 }
44 
45 void usage(void)
46 {
47 	last_do_help(last_argc - 1, last_argv + 1);
48 
49 	clean_and_exit(-1);
50 }
51 
52 static int do_help(int argc, char **argv)
53 {
54 	if (json_output) {
55 		jsonw_null(json_wtr);
56 		return 0;
57 	}
58 
59 	fprintf(stderr,
60 		"Usage: %s [OPTIONS] OBJECT { COMMAND | help }\n"
61 		"       %s batch file FILE\n"
62 		"       %s version\n"
63 		"\n"
64 		"       OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter }\n"
65 		"       " HELP_SPEC_OPTIONS " |\n"
66 		"                    {-V|--version} }\n"
67 		"",
68 		bin_name, bin_name, bin_name);
69 
70 	return 0;
71 }
72 
73 static int do_batch(int argc, char **argv);
74 static int do_version(int argc, char **argv);
75 
76 static const struct cmd commands[] = {
77 	{ "help",	do_help },
78 	{ "batch",	do_batch },
79 	{ "prog",	do_prog },
80 	{ "map",	do_map },
81 	{ "link",	do_link },
82 	{ "cgroup",	do_cgroup },
83 	{ "perf",	do_perf },
84 	{ "net",	do_net },
85 	{ "feature",	do_feature },
86 	{ "btf",	do_btf },
87 	{ "gen",	do_gen },
88 	{ "struct_ops",	do_struct_ops },
89 	{ "iter",	do_iter },
90 	{ "version",	do_version },
91 	{ 0 }
92 };
93 
94 #ifndef BPFTOOL_VERSION
95 /* bpftool's major and minor version numbers are aligned on libbpf's. There is
96  * an offset of 6 for the version number, because bpftool's version was higher
97  * than libbpf's when we adopted this scheme. The patch number remains at 0
98  * for now. Set BPFTOOL_VERSION to override.
99  */
100 #define BPFTOOL_MAJOR_VERSION (LIBBPF_MAJOR_VERSION + 6)
101 #define BPFTOOL_MINOR_VERSION LIBBPF_MINOR_VERSION
102 #define BPFTOOL_PATCH_VERSION 0
103 #endif
104 
105 static void
106 print_feature(const char *feature, bool state, unsigned int *nb_features)
107 {
108 	if (state) {
109 		printf("%s %s", *nb_features ? "," : "", feature);
110 		*nb_features = *nb_features + 1;
111 	}
112 }
113 
114 static int do_version(int argc, char **argv)
115 {
116 #ifdef HAVE_LIBBFD_SUPPORT
117 	const bool has_libbfd = true;
118 #else
119 	const bool has_libbfd = false;
120 #endif
121 #ifdef HAVE_LLVM_SUPPORT
122 	const bool has_llvm = true;
123 #else
124 	const bool has_llvm = false;
125 #endif
126 #ifdef BPFTOOL_WITHOUT_SKELETONS
127 	const bool has_skeletons = false;
128 #else
129 	const bool has_skeletons = true;
130 #endif
131 	bool bootstrap = false;
132 	int i;
133 
134 	for (i = 0; commands[i].cmd; i++) {
135 		if (!strcmp(commands[i].cmd, "prog")) {
136 			/* Assume we run a bootstrap version if "bpftool prog"
137 			 * is not available.
138 			 */
139 			bootstrap = !commands[i].func;
140 			break;
141 		}
142 	}
143 
144 	if (json_output) {
145 		jsonw_start_object(json_wtr);	/* root object */
146 
147 		jsonw_name(json_wtr, "version");
148 #ifdef BPFTOOL_VERSION
149 		jsonw_printf(json_wtr, "\"%s\"", BPFTOOL_VERSION);
150 #else
151 		jsonw_printf(json_wtr, "\"%d.%d.%d\"", BPFTOOL_MAJOR_VERSION,
152 			     BPFTOOL_MINOR_VERSION, BPFTOOL_PATCH_VERSION);
153 #endif
154 		jsonw_name(json_wtr, "libbpf_version");
155 		jsonw_printf(json_wtr, "\"%d.%d\"",
156 			     libbpf_major_version(), libbpf_minor_version());
157 
158 		jsonw_name(json_wtr, "features");
159 		jsonw_start_object(json_wtr);	/* features */
160 		jsonw_bool_field(json_wtr, "libbfd", has_libbfd);
161 		jsonw_bool_field(json_wtr, "llvm", has_llvm);
162 		jsonw_bool_field(json_wtr, "skeletons", has_skeletons);
163 		jsonw_bool_field(json_wtr, "bootstrap", bootstrap);
164 		jsonw_end_object(json_wtr);	/* features */
165 
166 		jsonw_end_object(json_wtr);	/* root object */
167 	} else {
168 		unsigned int nb_features = 0;
169 
170 #ifdef BPFTOOL_VERSION
171 		printf("%s v%s\n", bin_name, BPFTOOL_VERSION);
172 #else
173 		printf("%s v%d.%d.%d\n", bin_name, BPFTOOL_MAJOR_VERSION,
174 		       BPFTOOL_MINOR_VERSION, BPFTOOL_PATCH_VERSION);
175 #endif
176 		printf("using libbpf %s\n", libbpf_version_string());
177 		printf("features:");
178 		print_feature("libbfd", has_libbfd, &nb_features);
179 		print_feature("llvm", has_llvm, &nb_features);
180 		print_feature("skeletons", has_skeletons, &nb_features);
181 		print_feature("bootstrap", bootstrap, &nb_features);
182 		printf("\n");
183 	}
184 	return 0;
185 }
186 
187 int cmd_select(const struct cmd *cmds, int argc, char **argv,
188 	       int (*help)(int argc, char **argv))
189 {
190 	unsigned int i;
191 
192 	last_argc = argc;
193 	last_argv = argv;
194 	last_do_help = help;
195 
196 	if (argc < 1 && cmds[0].func)
197 		return cmds[0].func(argc, argv);
198 
199 	for (i = 0; cmds[i].cmd; i++) {
200 		if (is_prefix(*argv, cmds[i].cmd)) {
201 			if (!cmds[i].func) {
202 				p_err("command '%s' is not supported in bootstrap mode",
203 				      cmds[i].cmd);
204 				return -1;
205 			}
206 			return cmds[i].func(argc - 1, argv + 1);
207 		}
208 	}
209 
210 	help(argc - 1, argv + 1);
211 
212 	return -1;
213 }
214 
215 bool is_prefix(const char *pfx, const char *str)
216 {
217 	if (!pfx)
218 		return false;
219 	if (strlen(str) < strlen(pfx))
220 		return false;
221 
222 	return !memcmp(str, pfx, strlen(pfx));
223 }
224 
225 /* Last argument MUST be NULL pointer */
226 int detect_common_prefix(const char *arg, ...)
227 {
228 	unsigned int count = 0;
229 	const char *ref;
230 	char msg[256];
231 	va_list ap;
232 
233 	snprintf(msg, sizeof(msg), "ambiguous prefix: '%s' could be '", arg);
234 	va_start(ap, arg);
235 	while ((ref = va_arg(ap, const char *))) {
236 		if (!is_prefix(arg, ref))
237 			continue;
238 		count++;
239 		if (count > 1)
240 			strncat(msg, "' or '", sizeof(msg) - strlen(msg) - 1);
241 		strncat(msg, ref, sizeof(msg) - strlen(msg) - 1);
242 	}
243 	va_end(ap);
244 	strncat(msg, "'", sizeof(msg) - strlen(msg) - 1);
245 
246 	if (count >= 2) {
247 		p_err("%s", msg);
248 		return -1;
249 	}
250 
251 	return 0;
252 }
253 
254 void fprint_hex(FILE *f, void *arg, unsigned int n, const char *sep)
255 {
256 	unsigned char *data = arg;
257 	unsigned int i;
258 
259 	for (i = 0; i < n; i++) {
260 		const char *pfx = "";
261 
262 		if (!i)
263 			/* nothing */;
264 		else if (!(i % 16))
265 			fprintf(f, "\n");
266 		else if (!(i % 8))
267 			fprintf(f, "  ");
268 		else
269 			pfx = sep;
270 
271 		fprintf(f, "%s%02hhx", i ? pfx : "", data[i]);
272 	}
273 }
274 
275 /* Split command line into argument vector. */
276 static int make_args(char *line, char *n_argv[], int maxargs, int cmd_nb)
277 {
278 	static const char ws[] = " \t\r\n";
279 	char *cp = line;
280 	int n_argc = 0;
281 
282 	while (*cp) {
283 		/* Skip leading whitespace. */
284 		cp += strspn(cp, ws);
285 
286 		if (*cp == '\0')
287 			break;
288 
289 		if (n_argc >= (maxargs - 1)) {
290 			p_err("too many arguments to command %d", cmd_nb);
291 			return -1;
292 		}
293 
294 		/* Word begins with quote. */
295 		if (*cp == '\'' || *cp == '"') {
296 			char quote = *cp++;
297 
298 			n_argv[n_argc++] = cp;
299 			/* Find ending quote. */
300 			cp = strchr(cp, quote);
301 			if (!cp) {
302 				p_err("unterminated quoted string in command %d",
303 				      cmd_nb);
304 				return -1;
305 			}
306 		} else {
307 			n_argv[n_argc++] = cp;
308 
309 			/* Find end of word. */
310 			cp += strcspn(cp, ws);
311 			if (*cp == '\0')
312 				break;
313 		}
314 
315 		/* Separate words. */
316 		*cp++ = 0;
317 	}
318 	n_argv[n_argc] = NULL;
319 
320 	return n_argc;
321 }
322 
323 static int do_batch(int argc, char **argv)
324 {
325 	char buf[BATCH_LINE_LEN_MAX], contline[BATCH_LINE_LEN_MAX];
326 	char *n_argv[BATCH_ARG_NB_MAX];
327 	unsigned int lines = 0;
328 	int n_argc;
329 	FILE *fp;
330 	char *cp;
331 	int err = 0;
332 	int i;
333 
334 	if (argc < 2) {
335 		p_err("too few parameters for batch");
336 		return -1;
337 	} else if (argc > 2) {
338 		p_err("too many parameters for batch");
339 		return -1;
340 	} else if (!is_prefix(*argv, "file")) {
341 		p_err("expected 'file', got: %s", *argv);
342 		return -1;
343 	}
344 	NEXT_ARG();
345 
346 	if (!strcmp(*argv, "-"))
347 		fp = stdin;
348 	else
349 		fp = fopen(*argv, "r");
350 	if (!fp) {
351 		p_err("Can't open file (%s): %s", *argv, strerror(errno));
352 		return -1;
353 	}
354 
355 	if (json_output)
356 		jsonw_start_array(json_wtr);
357 	while (fgets(buf, sizeof(buf), fp)) {
358 		cp = strchr(buf, '#');
359 		if (cp)
360 			*cp = '\0';
361 
362 		if (strlen(buf) == sizeof(buf) - 1) {
363 			errno = E2BIG;
364 			break;
365 		}
366 
367 		/* Append continuation lines if any (coming after a line ending
368 		 * with '\' in the batch file).
369 		 */
370 		while ((cp = strstr(buf, "\\\n")) != NULL) {
371 			if (!fgets(contline, sizeof(contline), fp) ||
372 			    strlen(contline) == 0) {
373 				p_err("missing continuation line on command %d",
374 				      lines);
375 				err = -1;
376 				goto err_close;
377 			}
378 
379 			cp = strchr(contline, '#');
380 			if (cp)
381 				*cp = '\0';
382 
383 			if (strlen(buf) + strlen(contline) + 1 > sizeof(buf)) {
384 				p_err("command %d is too long", lines);
385 				err = -1;
386 				goto err_close;
387 			}
388 			buf[strlen(buf) - 2] = '\0';
389 			strcat(buf, contline);
390 		}
391 
392 		n_argc = make_args(buf, n_argv, BATCH_ARG_NB_MAX, lines);
393 		if (!n_argc)
394 			continue;
395 		if (n_argc < 0) {
396 			err = n_argc;
397 			goto err_close;
398 		}
399 
400 		if (json_output) {
401 			jsonw_start_object(json_wtr);
402 			jsonw_name(json_wtr, "command");
403 			jsonw_start_array(json_wtr);
404 			for (i = 0; i < n_argc; i++)
405 				jsonw_string(json_wtr, n_argv[i]);
406 			jsonw_end_array(json_wtr);
407 			jsonw_name(json_wtr, "output");
408 		}
409 
410 		err = cmd_select(commands, n_argc, n_argv, do_help);
411 
412 		if (json_output)
413 			jsonw_end_object(json_wtr);
414 
415 		if (err)
416 			goto err_close;
417 
418 		lines++;
419 	}
420 
421 	if (errno && errno != ENOENT) {
422 		p_err("reading batch file failed: %s", strerror(errno));
423 		err = -1;
424 	} else {
425 		if (!json_output)
426 			printf("processed %d commands\n", lines);
427 	}
428 err_close:
429 	if (fp != stdin)
430 		fclose(fp);
431 
432 	if (json_output)
433 		jsonw_end_array(json_wtr);
434 
435 	return err;
436 }
437 
438 int main(int argc, char **argv)
439 {
440 	static const struct option options[] = {
441 		{ "json",	no_argument,	NULL,	'j' },
442 		{ "help",	no_argument,	NULL,	'h' },
443 		{ "pretty",	no_argument,	NULL,	'p' },
444 		{ "version",	no_argument,	NULL,	'V' },
445 		{ "bpffs",	no_argument,	NULL,	'f' },
446 		{ "mapcompat",	no_argument,	NULL,	'm' },
447 		{ "nomount",	no_argument,	NULL,	'n' },
448 		{ "debug",	no_argument,	NULL,	'd' },
449 		{ "use-loader",	no_argument,	NULL,	'L' },
450 		{ "base-btf",	required_argument, NULL, 'B' },
451 		{ 0 }
452 	};
453 	bool version_requested = false;
454 	int opt, ret;
455 
456 	setlinebuf(stdout);
457 
458 #ifdef USE_LIBCAP
459 	/* Libcap < 2.63 hooks before main() to compute the number of
460 	 * capabilities of the running kernel, and doing so it calls prctl()
461 	 * which may fail and set errno to non-zero.
462 	 * Let's reset errno to make sure this does not interfere with the
463 	 * batch mode.
464 	 */
465 	errno = 0;
466 #endif
467 
468 	last_do_help = do_help;
469 	pretty_output = false;
470 	json_output = false;
471 	show_pinned = false;
472 	block_mount = false;
473 	bin_name = "bpftool";
474 
475 	opterr = 0;
476 	while ((opt = getopt_long(argc, argv, "VhpjfLmndB:l",
477 				  options, NULL)) >= 0) {
478 		switch (opt) {
479 		case 'V':
480 			version_requested = true;
481 			break;
482 		case 'h':
483 			return do_help(argc, argv);
484 		case 'p':
485 			pretty_output = true;
486 			/* fall through */
487 		case 'j':
488 			if (!json_output) {
489 				json_wtr = jsonw_new(stdout);
490 				if (!json_wtr) {
491 					p_err("failed to create JSON writer");
492 					return -1;
493 				}
494 				json_output = true;
495 			}
496 			jsonw_pretty(json_wtr, pretty_output);
497 			break;
498 		case 'f':
499 			show_pinned = true;
500 			break;
501 		case 'm':
502 			relaxed_maps = true;
503 			break;
504 		case 'n':
505 			block_mount = true;
506 			break;
507 		case 'd':
508 			libbpf_set_print(print_all_levels);
509 			verifier_logs = true;
510 			break;
511 		case 'B':
512 			base_btf = btf__parse(optarg, NULL);
513 			if (!base_btf) {
514 				p_err("failed to parse base BTF at '%s': %d\n",
515 				      optarg, -errno);
516 				return -1;
517 			}
518 			break;
519 		case 'L':
520 			use_loader = true;
521 			break;
522 		default:
523 			p_err("unrecognized option '%s'", argv[optind - 1]);
524 			if (json_output)
525 				clean_and_exit(-1);
526 			else
527 				usage();
528 		}
529 	}
530 
531 	argc -= optind;
532 	argv += optind;
533 	if (argc < 0)
534 		usage();
535 
536 	if (version_requested)
537 		return do_version(argc, argv);
538 
539 	ret = cmd_select(commands, argc, argv, do_help);
540 
541 	if (json_output)
542 		jsonw_destroy(&json_wtr);
543 
544 	btf__free(base_btf);
545 
546 	return ret;
547 }
548