xref: /linux/tools/bpf/bpftool/gen.c (revision 41fb0cf1bced59c1fe178cf6cc9f716b5da9e40e)
1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2019 Facebook */
3 
4 #ifndef _GNU_SOURCE
5 #define _GNU_SOURCE
6 #endif
7 #include <ctype.h>
8 #include <errno.h>
9 #include <fcntl.h>
10 #include <linux/err.h>
11 #include <stdbool.h>
12 #include <stdio.h>
13 #include <string.h>
14 #include <unistd.h>
15 #include <bpf/bpf.h>
16 #include <bpf/libbpf.h>
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <sys/mman.h>
20 #include <bpf/btf.h>
21 
22 #include "json_writer.h"
23 #include "main.h"
24 
25 #define MAX_OBJ_NAME_LEN 64
26 
27 static void sanitize_identifier(char *name)
28 {
29 	int i;
30 
31 	for (i = 0; name[i]; i++)
32 		if (!isalnum(name[i]) && name[i] != '_')
33 			name[i] = '_';
34 }
35 
36 static bool str_has_prefix(const char *str, const char *prefix)
37 {
38 	return strncmp(str, prefix, strlen(prefix)) == 0;
39 }
40 
41 static bool str_has_suffix(const char *str, const char *suffix)
42 {
43 	size_t i, n1 = strlen(str), n2 = strlen(suffix);
44 
45 	if (n1 < n2)
46 		return false;
47 
48 	for (i = 0; i < n2; i++) {
49 		if (str[n1 - i - 1] != suffix[n2 - i - 1])
50 			return false;
51 	}
52 
53 	return true;
54 }
55 
56 static void get_obj_name(char *name, const char *file)
57 {
58 	/* Using basename() GNU version which doesn't modify arg. */
59 	strncpy(name, basename(file), MAX_OBJ_NAME_LEN - 1);
60 	name[MAX_OBJ_NAME_LEN - 1] = '\0';
61 	if (str_has_suffix(name, ".o"))
62 		name[strlen(name) - 2] = '\0';
63 	sanitize_identifier(name);
64 }
65 
66 static void get_header_guard(char *guard, const char *obj_name)
67 {
68 	int i;
69 
70 	sprintf(guard, "__%s_SKEL_H__", obj_name);
71 	for (i = 0; guard[i]; i++)
72 		guard[i] = toupper(guard[i]);
73 }
74 
75 static bool get_map_ident(const struct bpf_map *map, char *buf, size_t buf_sz)
76 {
77 	static const char *sfxs[] = { ".data", ".rodata", ".bss", ".kconfig" };
78 	const char *name = bpf_map__name(map);
79 	int i, n;
80 
81 	if (!bpf_map__is_internal(map)) {
82 		snprintf(buf, buf_sz, "%s", name);
83 		return true;
84 	}
85 
86 	for  (i = 0, n = ARRAY_SIZE(sfxs); i < n; i++) {
87 		const char *sfx = sfxs[i], *p;
88 
89 		p = strstr(name, sfx);
90 		if (p) {
91 			snprintf(buf, buf_sz, "%s", p + 1);
92 			sanitize_identifier(buf);
93 			return true;
94 		}
95 	}
96 
97 	return false;
98 }
99 
100 static bool get_datasec_ident(const char *sec_name, char *buf, size_t buf_sz)
101 {
102 	static const char *pfxs[] = { ".data", ".rodata", ".bss", ".kconfig" };
103 	int i, n;
104 
105 	for  (i = 0, n = ARRAY_SIZE(pfxs); i < n; i++) {
106 		const char *pfx = pfxs[i];
107 
108 		if (str_has_prefix(sec_name, pfx)) {
109 			snprintf(buf, buf_sz, "%s", sec_name + 1);
110 			sanitize_identifier(buf);
111 			return true;
112 		}
113 	}
114 
115 	return false;
116 }
117 
118 static void codegen_btf_dump_printf(void *ctx, const char *fmt, va_list args)
119 {
120 	vprintf(fmt, args);
121 }
122 
123 static int codegen_datasec_def(struct bpf_object *obj,
124 			       struct btf *btf,
125 			       struct btf_dump *d,
126 			       const struct btf_type *sec,
127 			       const char *obj_name)
128 {
129 	const char *sec_name = btf__name_by_offset(btf, sec->name_off);
130 	const struct btf_var_secinfo *sec_var = btf_var_secinfos(sec);
131 	int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec);
132 	char var_ident[256], sec_ident[256];
133 	bool strip_mods = false;
134 
135 	if (!get_datasec_ident(sec_name, sec_ident, sizeof(sec_ident)))
136 		return 0;
137 
138 	if (strcmp(sec_name, ".kconfig") != 0)
139 		strip_mods = true;
140 
141 	printf("	struct %s__%s {\n", obj_name, sec_ident);
142 	for (i = 0; i < vlen; i++, sec_var++) {
143 		const struct btf_type *var = btf__type_by_id(btf, sec_var->type);
144 		const char *var_name = btf__name_by_offset(btf, var->name_off);
145 		DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
146 			.field_name = var_ident,
147 			.indent_level = 2,
148 			.strip_mods = strip_mods,
149 		);
150 		int need_off = sec_var->offset, align_off, align;
151 		__u32 var_type_id = var->type;
152 
153 		/* static variables are not exposed through BPF skeleton */
154 		if (btf_var(var)->linkage == BTF_VAR_STATIC)
155 			continue;
156 
157 		if (off > need_off) {
158 			p_err("Something is wrong for %s's variable #%d: need offset %d, already at %d.\n",
159 			      sec_name, i, need_off, off);
160 			return -EINVAL;
161 		}
162 
163 		align = btf__align_of(btf, var->type);
164 		if (align <= 0) {
165 			p_err("Failed to determine alignment of variable '%s': %d",
166 			      var_name, align);
167 			return -EINVAL;
168 		}
169 		/* Assume 32-bit architectures when generating data section
170 		 * struct memory layout. Given bpftool can't know which target
171 		 * host architecture it's emitting skeleton for, we need to be
172 		 * conservative and assume 32-bit one to ensure enough padding
173 		 * bytes are generated for pointer and long types. This will
174 		 * still work correctly for 64-bit architectures, because in
175 		 * the worst case we'll generate unnecessary padding field,
176 		 * which on 64-bit architectures is not strictly necessary and
177 		 * would be handled by natural 8-byte alignment. But it still
178 		 * will be a correct memory layout, based on recorded offsets
179 		 * in BTF.
180 		 */
181 		if (align > 4)
182 			align = 4;
183 
184 		align_off = (off + align - 1) / align * align;
185 		if (align_off != need_off) {
186 			printf("\t\tchar __pad%d[%d];\n",
187 			       pad_cnt, need_off - off);
188 			pad_cnt++;
189 		}
190 
191 		/* sanitize variable name, e.g., for static vars inside
192 		 * a function, it's name is '<function name>.<variable name>',
193 		 * which we'll turn into a '<function name>_<variable name>'
194 		 */
195 		var_ident[0] = '\0';
196 		strncat(var_ident, var_name, sizeof(var_ident) - 1);
197 		sanitize_identifier(var_ident);
198 
199 		printf("\t\t");
200 		err = btf_dump__emit_type_decl(d, var_type_id, &opts);
201 		if (err)
202 			return err;
203 		printf(";\n");
204 
205 		off = sec_var->offset + sec_var->size;
206 	}
207 	printf("	} *%s;\n", sec_ident);
208 	return 0;
209 }
210 
211 static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
212 {
213 	struct btf *btf = bpf_object__btf(obj);
214 	int n = btf__type_cnt(btf);
215 	struct btf_dump *d;
216 	struct bpf_map *map;
217 	const struct btf_type *sec;
218 	char sec_ident[256], map_ident[256];
219 	int i, err = 0;
220 
221 	d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL);
222 	err = libbpf_get_error(d);
223 	if (err)
224 		return err;
225 
226 	bpf_object__for_each_map(map, obj) {
227 		/* only generate definitions for memory-mapped internal maps */
228 		if (!bpf_map__is_internal(map))
229 			continue;
230 		if (!(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
231 			continue;
232 
233 		if (!get_map_ident(map, map_ident, sizeof(map_ident)))
234 			continue;
235 
236 		sec = NULL;
237 		for (i = 1; i < n; i++) {
238 			const struct btf_type *t = btf__type_by_id(btf, i);
239 			const char *name;
240 
241 			if (!btf_is_datasec(t))
242 				continue;
243 
244 			name = btf__str_by_offset(btf, t->name_off);
245 			if (!get_datasec_ident(name, sec_ident, sizeof(sec_ident)))
246 				continue;
247 
248 			if (strcmp(sec_ident, map_ident) == 0) {
249 				sec = t;
250 				break;
251 			}
252 		}
253 
254 		/* In some cases (e.g., sections like .rodata.cst16 containing
255 		 * compiler allocated string constants only) there will be
256 		 * special internal maps with no corresponding DATASEC BTF
257 		 * type. In such case, generate empty structs for each such
258 		 * map. It will still be memory-mapped and its contents
259 		 * accessible from user-space through BPF skeleton.
260 		 */
261 		if (!sec) {
262 			printf("	struct %s__%s {\n", obj_name, map_ident);
263 			printf("	} *%s;\n", map_ident);
264 		} else {
265 			err = codegen_datasec_def(obj, btf, d, sec, obj_name);
266 			if (err)
267 				goto out;
268 		}
269 	}
270 
271 
272 out:
273 	btf_dump__free(d);
274 	return err;
275 }
276 
277 static void codegen(const char *template, ...)
278 {
279 	const char *src, *end;
280 	int skip_tabs = 0, n;
281 	char *s, *dst;
282 	va_list args;
283 	char c;
284 
285 	n = strlen(template);
286 	s = malloc(n + 1);
287 	if (!s)
288 		exit(-1);
289 	src = template;
290 	dst = s;
291 
292 	/* find out "baseline" indentation to skip */
293 	while ((c = *src++)) {
294 		if (c == '\t') {
295 			skip_tabs++;
296 		} else if (c == '\n') {
297 			break;
298 		} else {
299 			p_err("unrecognized character at pos %td in template '%s': '%c'",
300 			      src - template - 1, template, c);
301 			free(s);
302 			exit(-1);
303 		}
304 	}
305 
306 	while (*src) {
307 		/* skip baseline indentation tabs */
308 		for (n = skip_tabs; n > 0; n--, src++) {
309 			if (*src != '\t') {
310 				p_err("not enough tabs at pos %td in template '%s'",
311 				      src - template - 1, template);
312 				free(s);
313 				exit(-1);
314 			}
315 		}
316 		/* trim trailing whitespace */
317 		end = strchrnul(src, '\n');
318 		for (n = end - src; n > 0 && isspace(src[n - 1]); n--)
319 			;
320 		memcpy(dst, src, n);
321 		dst += n;
322 		if (*end)
323 			*dst++ = '\n';
324 		src = *end ? end + 1 : end;
325 	}
326 	*dst++ = '\0';
327 
328 	/* print out using adjusted template */
329 	va_start(args, template);
330 	n = vprintf(s, args);
331 	va_end(args);
332 
333 	free(s);
334 }
335 
336 static void print_hex(const char *data, int data_sz)
337 {
338 	int i, len;
339 
340 	for (i = 0, len = 0; i < data_sz; i++) {
341 		int w = data[i] ? 4 : 2;
342 
343 		len += w;
344 		if (len > 78) {
345 			printf("\\\n");
346 			len = w;
347 		}
348 		if (!data[i])
349 			printf("\\0");
350 		else
351 			printf("\\x%02x", (unsigned char)data[i]);
352 	}
353 }
354 
355 static size_t bpf_map_mmap_sz(const struct bpf_map *map)
356 {
357 	long page_sz = sysconf(_SC_PAGE_SIZE);
358 	size_t map_sz;
359 
360 	map_sz = (size_t)roundup(bpf_map__value_size(map), 8) * bpf_map__max_entries(map);
361 	map_sz = roundup(map_sz, page_sz);
362 	return map_sz;
363 }
364 
365 static void codegen_attach_detach(struct bpf_object *obj, const char *obj_name)
366 {
367 	struct bpf_program *prog;
368 
369 	bpf_object__for_each_program(prog, obj) {
370 		const char *tp_name;
371 
372 		codegen("\
373 			\n\
374 			\n\
375 			static inline int					    \n\
376 			%1$s__%2$s__attach(struct %1$s *skel)			    \n\
377 			{							    \n\
378 				int prog_fd = skel->progs.%2$s.prog_fd;		    \n\
379 			", obj_name, bpf_program__name(prog));
380 
381 		switch (bpf_program__get_type(prog)) {
382 		case BPF_PROG_TYPE_RAW_TRACEPOINT:
383 			tp_name = strchr(bpf_program__section_name(prog), '/') + 1;
384 			printf("\tint fd = bpf_raw_tracepoint_open(\"%s\", prog_fd);\n", tp_name);
385 			break;
386 		case BPF_PROG_TYPE_TRACING:
387 			printf("\tint fd = bpf_raw_tracepoint_open(NULL, prog_fd);\n");
388 			break;
389 		default:
390 			printf("\tint fd = ((void)prog_fd, 0); /* auto-attach not supported */\n");
391 			break;
392 		}
393 		codegen("\
394 			\n\
395 										    \n\
396 				if (fd > 0)					    \n\
397 					skel->links.%1$s_fd = fd;		    \n\
398 				return fd;					    \n\
399 			}							    \n\
400 			", bpf_program__name(prog));
401 	}
402 
403 	codegen("\
404 		\n\
405 									    \n\
406 		static inline int					    \n\
407 		%1$s__attach(struct %1$s *skel)				    \n\
408 		{							    \n\
409 			int ret = 0;					    \n\
410 									    \n\
411 		", obj_name);
412 
413 	bpf_object__for_each_program(prog, obj) {
414 		codegen("\
415 			\n\
416 				ret = ret < 0 ? ret : %1$s__%2$s__attach(skel);   \n\
417 			", obj_name, bpf_program__name(prog));
418 	}
419 
420 	codegen("\
421 		\n\
422 			return ret < 0 ? ret : 0;			    \n\
423 		}							    \n\
424 									    \n\
425 		static inline void					    \n\
426 		%1$s__detach(struct %1$s *skel)				    \n\
427 		{							    \n\
428 		", obj_name);
429 
430 	bpf_object__for_each_program(prog, obj) {
431 		codegen("\
432 			\n\
433 				skel_closenz(skel->links.%1$s_fd);	    \n\
434 			", bpf_program__name(prog));
435 	}
436 
437 	codegen("\
438 		\n\
439 		}							    \n\
440 		");
441 }
442 
443 static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
444 {
445 	struct bpf_program *prog;
446 	struct bpf_map *map;
447 	char ident[256];
448 
449 	codegen("\
450 		\n\
451 		static void						    \n\
452 		%1$s__destroy(struct %1$s *skel)			    \n\
453 		{							    \n\
454 			if (!skel)					    \n\
455 				return;					    \n\
456 			%1$s__detach(skel);				    \n\
457 		",
458 		obj_name);
459 
460 	bpf_object__for_each_program(prog, obj) {
461 		codegen("\
462 			\n\
463 				skel_closenz(skel->progs.%1$s.prog_fd);	    \n\
464 			", bpf_program__name(prog));
465 	}
466 
467 	bpf_object__for_each_map(map, obj) {
468 		if (!get_map_ident(map, ident, sizeof(ident)))
469 			continue;
470 		if (bpf_map__is_internal(map) &&
471 		    (bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
472 			printf("\tmunmap(skel->%1$s, %2$zd);\n",
473 			       ident, bpf_map_mmap_sz(map));
474 		codegen("\
475 			\n\
476 				skel_closenz(skel->maps.%1$s.map_fd);	    \n\
477 			", ident);
478 	}
479 	codegen("\
480 		\n\
481 			free(skel);					    \n\
482 		}							    \n\
483 		",
484 		obj_name);
485 }
486 
487 static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *header_guard)
488 {
489 	struct bpf_object_load_attr load_attr = {};
490 	DECLARE_LIBBPF_OPTS(gen_loader_opts, opts);
491 	struct bpf_map *map;
492 	char ident[256];
493 	int err = 0;
494 
495 	err = bpf_object__gen_loader(obj, &opts);
496 	if (err)
497 		return err;
498 
499 	load_attr.obj = obj;
500 	if (verifier_logs)
501 		/* log_level1 + log_level2 + stats, but not stable UAPI */
502 		load_attr.log_level = 1 + 2 + 4;
503 
504 	err = bpf_object__load_xattr(&load_attr);
505 	if (err) {
506 		p_err("failed to load object file");
507 		goto out;
508 	}
509 	/* If there was no error during load then gen_loader_opts
510 	 * are populated with the loader program.
511 	 */
512 
513 	/* finish generating 'struct skel' */
514 	codegen("\
515 		\n\
516 		};							    \n\
517 		", obj_name);
518 
519 
520 	codegen_attach_detach(obj, obj_name);
521 
522 	codegen_destroy(obj, obj_name);
523 
524 	codegen("\
525 		\n\
526 		static inline struct %1$s *				    \n\
527 		%1$s__open(void)					    \n\
528 		{							    \n\
529 			struct %1$s *skel;				    \n\
530 									    \n\
531 			skel = calloc(sizeof(*skel), 1);		    \n\
532 			if (!skel)					    \n\
533 				goto cleanup;				    \n\
534 			skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
535 		",
536 		obj_name, opts.data_sz);
537 	bpf_object__for_each_map(map, obj) {
538 		const void *mmap_data = NULL;
539 		size_t mmap_size = 0;
540 
541 		if (!get_map_ident(map, ident, sizeof(ident)))
542 			continue;
543 
544 		if (!bpf_map__is_internal(map) ||
545 		    !(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
546 			continue;
547 
548 		codegen("\
549 			\n\
550 				skel->%1$s =					 \n\
551 					mmap(NULL, %2$zd, PROT_READ | PROT_WRITE,\n\
552 					     MAP_SHARED | MAP_ANONYMOUS, -1, 0); \n\
553 				if (skel->%1$s == (void *) -1)			 \n\
554 					goto cleanup;				 \n\
555 				memcpy(skel->%1$s, (void *)\"\\			 \n\
556 			", ident, bpf_map_mmap_sz(map));
557 		mmap_data = bpf_map__initial_value(map, &mmap_size);
558 		print_hex(mmap_data, mmap_size);
559 		printf("\", %2$zd);\n"
560 		       "\tskel->maps.%1$s.initial_value = (__u64)(long)skel->%1$s;\n",
561 		       ident, mmap_size);
562 	}
563 	codegen("\
564 		\n\
565 			return skel;					    \n\
566 		cleanup:						    \n\
567 			%1$s__destroy(skel);				    \n\
568 			return NULL;					    \n\
569 		}							    \n\
570 									    \n\
571 		static inline int					    \n\
572 		%1$s__load(struct %1$s *skel)				    \n\
573 		{							    \n\
574 			struct bpf_load_and_run_opts opts = {};		    \n\
575 			int err;					    \n\
576 									    \n\
577 			opts.ctx = (struct bpf_loader_ctx *)skel;	    \n\
578 			opts.data_sz = %2$d;				    \n\
579 			opts.data = (void *)\"\\			    \n\
580 		",
581 		obj_name, opts.data_sz);
582 	print_hex(opts.data, opts.data_sz);
583 	codegen("\
584 		\n\
585 		\";							    \n\
586 		");
587 
588 	codegen("\
589 		\n\
590 			opts.insns_sz = %d;				    \n\
591 			opts.insns = (void *)\"\\			    \n\
592 		",
593 		opts.insns_sz);
594 	print_hex(opts.insns, opts.insns_sz);
595 	codegen("\
596 		\n\
597 		\";							    \n\
598 			err = bpf_load_and_run(&opts);			    \n\
599 			if (err < 0)					    \n\
600 				return err;				    \n\
601 		", obj_name);
602 	bpf_object__for_each_map(map, obj) {
603 		const char *mmap_flags;
604 
605 		if (!get_map_ident(map, ident, sizeof(ident)))
606 			continue;
607 
608 		if (!bpf_map__is_internal(map) ||
609 		    !(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
610 			continue;
611 
612 		if (bpf_map__def(map)->map_flags & BPF_F_RDONLY_PROG)
613 			mmap_flags = "PROT_READ";
614 		else
615 			mmap_flags = "PROT_READ | PROT_WRITE";
616 
617 		printf("\tskel->%1$s =\n"
618 		       "\t\tmmap(skel->%1$s, %2$zd, %3$s, MAP_SHARED | MAP_FIXED,\n"
619 		       "\t\t\tskel->maps.%1$s.map_fd, 0);\n",
620 		       ident, bpf_map_mmap_sz(map), mmap_flags);
621 	}
622 	codegen("\
623 		\n\
624 			return 0;					    \n\
625 		}							    \n\
626 									    \n\
627 		static inline struct %1$s *				    \n\
628 		%1$s__open_and_load(void)				    \n\
629 		{							    \n\
630 			struct %1$s *skel;				    \n\
631 									    \n\
632 			skel = %1$s__open();				    \n\
633 			if (!skel)					    \n\
634 				return NULL;				    \n\
635 			if (%1$s__load(skel)) {				    \n\
636 				%1$s__destroy(skel);			    \n\
637 				return NULL;				    \n\
638 			}						    \n\
639 			return skel;					    \n\
640 		}							    \n\
641 		", obj_name);
642 
643 	codegen("\
644 		\n\
645 									    \n\
646 		#endif /* %s */						    \n\
647 		",
648 		header_guard);
649 	err = 0;
650 out:
651 	return err;
652 }
653 
654 static int do_skeleton(int argc, char **argv)
655 {
656 	char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
657 	size_t i, map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz;
658 	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
659 	char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data;
660 	struct bpf_object *obj = NULL;
661 	const char *file;
662 	char ident[256];
663 	struct bpf_program *prog;
664 	int fd, err = -1;
665 	struct bpf_map *map;
666 	struct btf *btf;
667 	struct stat st;
668 
669 	if (!REQ_ARGS(1)) {
670 		usage();
671 		return -1;
672 	}
673 	file = GET_ARG();
674 
675 	while (argc) {
676 		if (!REQ_ARGS(2))
677 			return -1;
678 
679 		if (is_prefix(*argv, "name")) {
680 			NEXT_ARG();
681 
682 			if (obj_name[0] != '\0') {
683 				p_err("object name already specified");
684 				return -1;
685 			}
686 
687 			strncpy(obj_name, *argv, MAX_OBJ_NAME_LEN - 1);
688 			obj_name[MAX_OBJ_NAME_LEN - 1] = '\0';
689 		} else {
690 			p_err("unknown arg %s", *argv);
691 			return -1;
692 		}
693 
694 		NEXT_ARG();
695 	}
696 
697 	if (argc) {
698 		p_err("extra unknown arguments");
699 		return -1;
700 	}
701 
702 	if (stat(file, &st)) {
703 		p_err("failed to stat() %s: %s", file, strerror(errno));
704 		return -1;
705 	}
706 	file_sz = st.st_size;
707 	mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE));
708 	fd = open(file, O_RDONLY);
709 	if (fd < 0) {
710 		p_err("failed to open() %s: %s", file, strerror(errno));
711 		return -1;
712 	}
713 	obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0);
714 	if (obj_data == MAP_FAILED) {
715 		obj_data = NULL;
716 		p_err("failed to mmap() %s: %s", file, strerror(errno));
717 		goto out;
718 	}
719 	if (obj_name[0] == '\0')
720 		get_obj_name(obj_name, file);
721 	opts.object_name = obj_name;
722 	obj = bpf_object__open_mem(obj_data, file_sz, &opts);
723 	err = libbpf_get_error(obj);
724 	if (err) {
725 		char err_buf[256];
726 
727 		libbpf_strerror(err, err_buf, sizeof(err_buf));
728 		p_err("failed to open BPF object file: %s", err_buf);
729 		obj = NULL;
730 		goto out;
731 	}
732 
733 	bpf_object__for_each_map(map, obj) {
734 		if (!get_map_ident(map, ident, sizeof(ident))) {
735 			p_err("ignoring unrecognized internal map '%s'...",
736 			      bpf_map__name(map));
737 			continue;
738 		}
739 		map_cnt++;
740 	}
741 	bpf_object__for_each_program(prog, obj) {
742 		prog_cnt++;
743 	}
744 
745 	get_header_guard(header_guard, obj_name);
746 	if (use_loader) {
747 		codegen("\
748 		\n\
749 		/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */   \n\
750 		/* THIS FILE IS AUTOGENERATED! */			    \n\
751 		#ifndef %2$s						    \n\
752 		#define %2$s						    \n\
753 									    \n\
754 		#include <stdlib.h>					    \n\
755 		#include <bpf/bpf.h>					    \n\
756 		#include <bpf/skel_internal.h>				    \n\
757 									    \n\
758 		struct %1$s {						    \n\
759 			struct bpf_loader_ctx ctx;			    \n\
760 		",
761 		obj_name, header_guard
762 		);
763 	} else {
764 		codegen("\
765 		\n\
766 		/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */   \n\
767 									    \n\
768 		/* THIS FILE IS AUTOGENERATED! */			    \n\
769 		#ifndef %2$s						    \n\
770 		#define %2$s						    \n\
771 									    \n\
772 		#include <errno.h>					    \n\
773 		#include <stdlib.h>					    \n\
774 		#include <bpf/libbpf.h>					    \n\
775 									    \n\
776 		struct %1$s {						    \n\
777 			struct bpf_object_skeleton *skeleton;		    \n\
778 			struct bpf_object *obj;				    \n\
779 		",
780 		obj_name, header_guard
781 		);
782 	}
783 
784 	if (map_cnt) {
785 		printf("\tstruct {\n");
786 		bpf_object__for_each_map(map, obj) {
787 			if (!get_map_ident(map, ident, sizeof(ident)))
788 				continue;
789 			if (use_loader)
790 				printf("\t\tstruct bpf_map_desc %s;\n", ident);
791 			else
792 				printf("\t\tstruct bpf_map *%s;\n", ident);
793 		}
794 		printf("\t} maps;\n");
795 	}
796 
797 	if (prog_cnt) {
798 		printf("\tstruct {\n");
799 		bpf_object__for_each_program(prog, obj) {
800 			if (use_loader)
801 				printf("\t\tstruct bpf_prog_desc %s;\n",
802 				       bpf_program__name(prog));
803 			else
804 				printf("\t\tstruct bpf_program *%s;\n",
805 				       bpf_program__name(prog));
806 		}
807 		printf("\t} progs;\n");
808 		printf("\tstruct {\n");
809 		bpf_object__for_each_program(prog, obj) {
810 			if (use_loader)
811 				printf("\t\tint %s_fd;\n",
812 				       bpf_program__name(prog));
813 			else
814 				printf("\t\tstruct bpf_link *%s;\n",
815 				       bpf_program__name(prog));
816 		}
817 		printf("\t} links;\n");
818 	}
819 
820 	btf = bpf_object__btf(obj);
821 	if (btf) {
822 		err = codegen_datasecs(obj, obj_name);
823 		if (err)
824 			goto out;
825 	}
826 	if (use_loader) {
827 		err = gen_trace(obj, obj_name, header_guard);
828 		goto out;
829 	}
830 
831 	codegen("\
832 		\n\
833 		};							    \n\
834 									    \n\
835 		static void						    \n\
836 		%1$s__destroy(struct %1$s *obj)				    \n\
837 		{							    \n\
838 			if (!obj)					    \n\
839 				return;					    \n\
840 			if (obj->skeleton)				    \n\
841 				bpf_object__destroy_skeleton(obj->skeleton);\n\
842 			free(obj);					    \n\
843 		}							    \n\
844 									    \n\
845 		static inline int					    \n\
846 		%1$s__create_skeleton(struct %1$s *obj);		    \n\
847 									    \n\
848 		static inline struct %1$s *				    \n\
849 		%1$s__open_opts(const struct bpf_object_open_opts *opts)    \n\
850 		{							    \n\
851 			struct %1$s *obj;				    \n\
852 			int err;					    \n\
853 									    \n\
854 			obj = (struct %1$s *)calloc(1, sizeof(*obj));	    \n\
855 			if (!obj) {					    \n\
856 				errno = ENOMEM;				    \n\
857 				return NULL;				    \n\
858 			}						    \n\
859 									    \n\
860 			err = %1$s__create_skeleton(obj);		    \n\
861 			if (err)					    \n\
862 				goto err_out;				    \n\
863 									    \n\
864 			err = bpf_object__open_skeleton(obj->skeleton, opts);\n\
865 			if (err)					    \n\
866 				goto err_out;				    \n\
867 									    \n\
868 			return obj;					    \n\
869 		err_out:						    \n\
870 			%1$s__destroy(obj);				    \n\
871 			errno = -err;					    \n\
872 			return NULL;					    \n\
873 		}							    \n\
874 									    \n\
875 		static inline struct %1$s *				    \n\
876 		%1$s__open(void)					    \n\
877 		{							    \n\
878 			return %1$s__open_opts(NULL);			    \n\
879 		}							    \n\
880 									    \n\
881 		static inline int					    \n\
882 		%1$s__load(struct %1$s *obj)				    \n\
883 		{							    \n\
884 			return bpf_object__load_skeleton(obj->skeleton);    \n\
885 		}							    \n\
886 									    \n\
887 		static inline struct %1$s *				    \n\
888 		%1$s__open_and_load(void)				    \n\
889 		{							    \n\
890 			struct %1$s *obj;				    \n\
891 			int err;					    \n\
892 									    \n\
893 			obj = %1$s__open();				    \n\
894 			if (!obj)					    \n\
895 				return NULL;				    \n\
896 			err = %1$s__load(obj);				    \n\
897 			if (err) {					    \n\
898 				%1$s__destroy(obj);			    \n\
899 				errno = -err;				    \n\
900 				return NULL;				    \n\
901 			}						    \n\
902 			return obj;					    \n\
903 		}							    \n\
904 									    \n\
905 		static inline int					    \n\
906 		%1$s__attach(struct %1$s *obj)				    \n\
907 		{							    \n\
908 			return bpf_object__attach_skeleton(obj->skeleton);  \n\
909 		}							    \n\
910 									    \n\
911 		static inline void					    \n\
912 		%1$s__detach(struct %1$s *obj)				    \n\
913 		{							    \n\
914 			return bpf_object__detach_skeleton(obj->skeleton);  \n\
915 		}							    \n\
916 		",
917 		obj_name
918 	);
919 
920 	codegen("\
921 		\n\
922 									    \n\
923 		static inline const void *%1$s__elf_bytes(size_t *sz);	    \n\
924 									    \n\
925 		static inline int					    \n\
926 		%1$s__create_skeleton(struct %1$s *obj)			    \n\
927 		{							    \n\
928 			struct bpf_object_skeleton *s;			    \n\
929 									    \n\
930 			s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\
931 			if (!s)						    \n\
932 				goto err;				    \n\
933 			obj->skeleton = s;				    \n\
934 									    \n\
935 			s->sz = sizeof(*s);				    \n\
936 			s->name = \"%1$s\";				    \n\
937 			s->obj = &obj->obj;				    \n\
938 		",
939 		obj_name
940 	);
941 	if (map_cnt) {
942 		codegen("\
943 			\n\
944 									    \n\
945 				/* maps */				    \n\
946 				s->map_cnt = %zu;			    \n\
947 				s->map_skel_sz = sizeof(*s->maps);	    \n\
948 				s->maps = (struct bpf_map_skeleton *)calloc(s->map_cnt, s->map_skel_sz);\n\
949 				if (!s->maps)				    \n\
950 					goto err;			    \n\
951 			",
952 			map_cnt
953 		);
954 		i = 0;
955 		bpf_object__for_each_map(map, obj) {
956 			if (!get_map_ident(map, ident, sizeof(ident)))
957 				continue;
958 
959 			codegen("\
960 				\n\
961 									    \n\
962 					s->maps[%zu].name = \"%s\";	    \n\
963 					s->maps[%zu].map = &obj->maps.%s;   \n\
964 				",
965 				i, bpf_map__name(map), i, ident);
966 			/* memory-mapped internal maps */
967 			if (bpf_map__is_internal(map) &&
968 			    (bpf_map__def(map)->map_flags & BPF_F_MMAPABLE)) {
969 				printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n",
970 				       i, ident);
971 			}
972 			i++;
973 		}
974 	}
975 	if (prog_cnt) {
976 		codegen("\
977 			\n\
978 									    \n\
979 				/* programs */				    \n\
980 				s->prog_cnt = %zu;			    \n\
981 				s->prog_skel_sz = sizeof(*s->progs);	    \n\
982 				s->progs = (struct bpf_prog_skeleton *)calloc(s->prog_cnt, s->prog_skel_sz);\n\
983 				if (!s->progs)				    \n\
984 					goto err;			    \n\
985 			",
986 			prog_cnt
987 		);
988 		i = 0;
989 		bpf_object__for_each_program(prog, obj) {
990 			codegen("\
991 				\n\
992 									    \n\
993 					s->progs[%1$zu].name = \"%2$s\";    \n\
994 					s->progs[%1$zu].prog = &obj->progs.%2$s;\n\
995 					s->progs[%1$zu].link = &obj->links.%2$s;\n\
996 				",
997 				i, bpf_program__name(prog));
998 			i++;
999 		}
1000 	}
1001 	codegen("\
1002 		\n\
1003 									    \n\
1004 			s->data = (void *)%2$s__elf_bytes(&s->data_sz);	    \n\
1005 									    \n\
1006 			return 0;					    \n\
1007 		err:							    \n\
1008 			bpf_object__destroy_skeleton(s);		    \n\
1009 			return -ENOMEM;					    \n\
1010 		}							    \n\
1011 									    \n\
1012 		static inline const void *%2$s__elf_bytes(size_t *sz)	    \n\
1013 		{							    \n\
1014 			*sz = %1$d;					    \n\
1015 			return (const void *)\"\\			    \n\
1016 		"
1017 		, file_sz, obj_name);
1018 
1019 	/* embed contents of BPF object file */
1020 	print_hex(obj_data, file_sz);
1021 
1022 	codegen("\
1023 		\n\
1024 		\";							    \n\
1025 		}							    \n\
1026 									    \n\
1027 		#endif /* %s */						    \n\
1028 		",
1029 		header_guard);
1030 	err = 0;
1031 out:
1032 	bpf_object__close(obj);
1033 	if (obj_data)
1034 		munmap(obj_data, mmap_sz);
1035 	close(fd);
1036 	return err;
1037 }
1038 
1039 static int do_object(int argc, char **argv)
1040 {
1041 	struct bpf_linker *linker;
1042 	const char *output_file, *file;
1043 	int err = 0;
1044 
1045 	if (!REQ_ARGS(2)) {
1046 		usage();
1047 		return -1;
1048 	}
1049 
1050 	output_file = GET_ARG();
1051 
1052 	linker = bpf_linker__new(output_file, NULL);
1053 	if (!linker) {
1054 		p_err("failed to create BPF linker instance");
1055 		return -1;
1056 	}
1057 
1058 	while (argc) {
1059 		file = GET_ARG();
1060 
1061 		err = bpf_linker__add_file(linker, file, NULL);
1062 		if (err) {
1063 			p_err("failed to link '%s': %s (%d)", file, strerror(err), err);
1064 			goto out;
1065 		}
1066 	}
1067 
1068 	err = bpf_linker__finalize(linker);
1069 	if (err) {
1070 		p_err("failed to finalize ELF file: %s (%d)", strerror(err), err);
1071 		goto out;
1072 	}
1073 
1074 	err = 0;
1075 out:
1076 	bpf_linker__free(linker);
1077 	return err;
1078 }
1079 
1080 static int do_help(int argc, char **argv)
1081 {
1082 	if (json_output) {
1083 		jsonw_null(json_wtr);
1084 		return 0;
1085 	}
1086 
1087 	fprintf(stderr,
1088 		"Usage: %1$s %2$s object OUTPUT_FILE INPUT_FILE [INPUT_FILE...]\n"
1089 		"       %1$s %2$s skeleton FILE [name OBJECT_NAME]\n"
1090 		"       %1$s %2$s help\n"
1091 		"\n"
1092 		"       " HELP_SPEC_OPTIONS " |\n"
1093 		"                    {-L|--use-loader} }\n"
1094 		"",
1095 		bin_name, "gen");
1096 
1097 	return 0;
1098 }
1099 
1100 static const struct cmd cmds[] = {
1101 	{ "object",	do_object },
1102 	{ "skeleton",	do_skeleton },
1103 	{ "help",	do_help },
1104 	{ 0 }
1105 };
1106 
1107 int do_gen(int argc, char **argv)
1108 {
1109 	return cmd_select(cmds, argc, argv, do_help);
1110 }
1111