1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2/* Copyright (c) 2018 Facebook */
3
4#include <ctype.h>
5#include <stdio.h> /* for (FILE *) used by json_writer */
6#include <string.h>
7#include <unistd.h>
8#include <asm/byteorder.h>
9#include <linux/bitops.h>
10#include <linux/btf.h>
11#include <linux/err.h>
12#include <bpf/btf.h>
13#include <bpf/bpf.h>
14
15#include "json_writer.h"
16#include "main.h"
17
18#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
19#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
20#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
21#define BITS_ROUNDUP_BYTES(bits) \
22 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
23
24static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
25 __u8 bit_offset, const void *data);
26
27static int btf_dump_func(const struct btf *btf, char *func_sig,
28 const struct btf_type *func_proto,
29 const struct btf_type *func, int pos, int size);
30
31static int dump_prog_id_as_func_ptr(const struct btf_dumper *d,
32 const struct btf_type *func_proto,
33 __u32 prog_id)
34{
35 const struct btf_type *func_type;
36 int prog_fd = -1, func_sig_len;
37 struct bpf_prog_info info = {};
38 __u32 info_len = sizeof(info);
39 const char *prog_name = NULL;
40 struct btf *prog_btf = NULL;
41 struct bpf_func_info finfo;
42 __u32 finfo_rec_size;
43 char prog_str[1024];
44 int err;
45
46 /* Get the ptr's func_proto */
47 func_sig_len = btf_dump_func(btf: d->btf, func_sig: prog_str, func_proto, NULL, pos: 0,
48 size: sizeof(prog_str));
49 if (func_sig_len == -1)
50 return -1;
51
52 if (!prog_id)
53 goto print;
54
55 /* Get the bpf_prog's name. Obtain from func_info. */
56 prog_fd = bpf_prog_get_fd_by_id(prog_id);
57 if (prog_fd < 0)
58 goto print;
59
60 err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
61 if (err)
62 goto print;
63
64 if (!info.btf_id || !info.nr_func_info)
65 goto print;
66
67 finfo_rec_size = info.func_info_rec_size;
68 memset(&info, 0, sizeof(info));
69 info.nr_func_info = 1;
70 info.func_info_rec_size = finfo_rec_size;
71 info.func_info = ptr_to_u64(ptr: &finfo);
72
73 err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
74 if (err)
75 goto print;
76
77 prog_btf = btf__load_from_kernel_by_id(info.btf_id);
78 if (!prog_btf)
79 goto print;
80 func_type = btf__type_by_id(prog_btf, finfo.type_id);
81 if (!func_type || !btf_is_func(func_type))
82 goto print;
83
84 prog_name = btf__name_by_offset(prog_btf, func_type->name_off);
85
86print:
87 if (!prog_id)
88 snprintf(buf: &prog_str[func_sig_len],
89 size: sizeof(prog_str) - func_sig_len, fmt: " 0");
90 else if (prog_name)
91 snprintf(buf: &prog_str[func_sig_len],
92 size: sizeof(prog_str) - func_sig_len,
93 fmt: " %s/prog_id:%u", prog_name, prog_id);
94 else
95 snprintf(buf: &prog_str[func_sig_len],
96 size: sizeof(prog_str) - func_sig_len,
97 fmt: " <unknown_prog_name>/prog_id:%u", prog_id);
98
99 prog_str[sizeof(prog_str) - 1] = '\0';
100 jsonw_string(self: d->jw, value: prog_str);
101 btf__free(prog_btf);
102 if (prog_fd >= 0)
103 close(prog_fd);
104 return 0;
105}
106
107static void btf_dumper_ptr(const struct btf_dumper *d,
108 const struct btf_type *t,
109 const void *data)
110{
111 unsigned long value = *(unsigned long *)data;
112 const struct btf_type *ptr_type;
113 __s32 ptr_type_id;
114
115 if (!d->prog_id_as_func_ptr || value > UINT32_MAX)
116 goto print_ptr_value;
117
118 ptr_type_id = btf__resolve_type(d->btf, t->type);
119 if (ptr_type_id < 0)
120 goto print_ptr_value;
121 ptr_type = btf__type_by_id(d->btf, ptr_type_id);
122 if (!ptr_type || !btf_is_func_proto(ptr_type))
123 goto print_ptr_value;
124
125 if (!dump_prog_id_as_func_ptr(d, func_proto: ptr_type, prog_id: value))
126 return;
127
128print_ptr_value:
129 if (d->is_plain_text)
130 jsonw_printf(self: d->jw, fmt: "\"%p\"", (void *)value);
131 else
132 jsonw_printf(self: d->jw, fmt: "%lu", value);
133}
134
135static int btf_dumper_modifier(const struct btf_dumper *d, __u32 type_id,
136 __u8 bit_offset, const void *data)
137{
138 int actual_type_id;
139
140 actual_type_id = btf__resolve_type(d->btf, type_id);
141 if (actual_type_id < 0)
142 return actual_type_id;
143
144 return btf_dumper_do_type(d, type_id: actual_type_id, bit_offset, data);
145}
146
147static int btf_dumper_enum(const struct btf_dumper *d,
148 const struct btf_type *t,
149 const void *data)
150{
151 const struct btf_enum *enums = btf_enum(t);
152 __s64 value;
153 __u16 i;
154
155 switch (t->size) {
156 case 8:
157 value = *(__s64 *)data;
158 break;
159 case 4:
160 value = *(__s32 *)data;
161 break;
162 case 2:
163 value = *(__s16 *)data;
164 break;
165 case 1:
166 value = *(__s8 *)data;
167 break;
168 default:
169 return -EINVAL;
170 }
171
172 for (i = 0; i < btf_vlen(t); i++) {
173 if (value == enums[i].val) {
174 jsonw_string(self: d->jw,
175 value: btf__name_by_offset(d->btf,
176 enums[i].name_off));
177 return 0;
178 }
179 }
180
181 jsonw_int(self: d->jw, number: value);
182 return 0;
183}
184
185static int btf_dumper_enum64(const struct btf_dumper *d,
186 const struct btf_type *t,
187 const void *data)
188{
189 const struct btf_enum64 *enums = btf_enum64(t);
190 __u32 val_lo32, val_hi32;
191 __u64 value;
192 __u16 i;
193
194 value = *(__u64 *)data;
195 val_lo32 = (__u32)value;
196 val_hi32 = value >> 32;
197
198 for (i = 0; i < btf_vlen(t); i++) {
199 if (val_lo32 == enums[i].val_lo32 && val_hi32 == enums[i].val_hi32) {
200 jsonw_string(self: d->jw,
201 value: btf__name_by_offset(d->btf,
202 enums[i].name_off));
203 return 0;
204 }
205 }
206
207 jsonw_int(self: d->jw, number: value);
208 return 0;
209}
210
211static bool is_str_array(const struct btf *btf, const struct btf_array *arr,
212 const char *s)
213{
214 const struct btf_type *elem_type;
215 const char *end_s;
216
217 if (!arr->nelems)
218 return false;
219
220 elem_type = btf__type_by_id(btf, arr->type);
221 /* Not skipping typedef. typedef to char does not count as
222 * a string now.
223 */
224 while (elem_type && btf_is_mod(elem_type))
225 elem_type = btf__type_by_id(btf, elem_type->type);
226
227 if (!elem_type || !btf_is_int(t: elem_type) || elem_type->size != 1)
228 return false;
229
230 if (btf_int_encoding(t: elem_type) != BTF_INT_CHAR &&
231 strcmp("char", btf__name_by_offset(btf, elem_type->name_off)))
232 return false;
233
234 end_s = s + arr->nelems;
235 while (s < end_s) {
236 if (!*s)
237 return true;
238 if (*s <= 0x1f || *s >= 0x7f)
239 return false;
240 s++;
241 }
242
243 /* '\0' is not found */
244 return false;
245}
246
247static int btf_dumper_array(const struct btf_dumper *d, __u32 type_id,
248 const void *data)
249{
250 const struct btf_type *t = btf__type_by_id(d->btf, type_id);
251 struct btf_array *arr = (struct btf_array *)(t + 1);
252 long long elem_size;
253 int ret = 0;
254 __u32 i;
255
256 if (is_str_array(btf: d->btf, arr, s: data)) {
257 jsonw_string(self: d->jw, value: data);
258 return 0;
259 }
260
261 elem_size = btf__resolve_size(d->btf, arr->type);
262 if (elem_size < 0)
263 return elem_size;
264
265 jsonw_start_array(self: d->jw);
266 for (i = 0; i < arr->nelems; i++) {
267 ret = btf_dumper_do_type(d, type_id: arr->type, bit_offset: 0,
268 data: data + i * elem_size);
269 if (ret)
270 break;
271 }
272
273 jsonw_end_array(self: d->jw);
274 return ret;
275}
276
277static void btf_int128_print(json_writer_t *jw, const void *data,
278 bool is_plain_text)
279{
280 /* data points to a __int128 number.
281 * Suppose
282 * int128_num = *(__int128 *)data;
283 * The below formulas shows what upper_num and lower_num represents:
284 * upper_num = int128_num >> 64;
285 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
286 */
287 __u64 upper_num, lower_num;
288
289#ifdef __BIG_ENDIAN_BITFIELD
290 upper_num = *(__u64 *)data;
291 lower_num = *(__u64 *)(data + 8);
292#else
293 upper_num = *(__u64 *)(data + 8);
294 lower_num = *(__u64 *)data;
295#endif
296
297 if (is_plain_text) {
298 if (upper_num == 0)
299 jsonw_printf(self: jw, fmt: "0x%llx", lower_num);
300 else
301 jsonw_printf(self: jw, fmt: "0x%llx%016llx", upper_num, lower_num);
302 } else {
303 if (upper_num == 0)
304 jsonw_printf(self: jw, fmt: "\"0x%llx\"", lower_num);
305 else
306 jsonw_printf(self: jw, fmt: "\"0x%llx%016llx\"", upper_num, lower_num);
307 }
308}
309
310static void btf_int128_shift(__u64 *print_num, __u16 left_shift_bits,
311 __u16 right_shift_bits)
312{
313 __u64 upper_num, lower_num;
314
315#ifdef __BIG_ENDIAN_BITFIELD
316 upper_num = print_num[0];
317 lower_num = print_num[1];
318#else
319 upper_num = print_num[1];
320 lower_num = print_num[0];
321#endif
322
323 /* shake out un-needed bits by shift/or operations */
324 if (left_shift_bits >= 64) {
325 upper_num = lower_num << (left_shift_bits - 64);
326 lower_num = 0;
327 } else {
328 upper_num = (upper_num << left_shift_bits) |
329 (lower_num >> (64 - left_shift_bits));
330 lower_num = lower_num << left_shift_bits;
331 }
332
333 if (right_shift_bits >= 64) {
334 lower_num = upper_num >> (right_shift_bits - 64);
335 upper_num = 0;
336 } else {
337 lower_num = (lower_num >> right_shift_bits) |
338 (upper_num << (64 - right_shift_bits));
339 upper_num = upper_num >> right_shift_bits;
340 }
341
342#ifdef __BIG_ENDIAN_BITFIELD
343 print_num[0] = upper_num;
344 print_num[1] = lower_num;
345#else
346 print_num[0] = lower_num;
347 print_num[1] = upper_num;
348#endif
349}
350
351static void btf_dumper_bitfield(__u32 nr_bits, __u8 bit_offset,
352 const void *data, json_writer_t *jw,
353 bool is_plain_text)
354{
355 int left_shift_bits, right_shift_bits;
356 __u64 print_num[2] = {};
357 int bytes_to_copy;
358 int bits_to_copy;
359
360 bits_to_copy = bit_offset + nr_bits;
361 bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
362
363 memcpy(print_num, data, bytes_to_copy);
364#if defined(__BIG_ENDIAN_BITFIELD)
365 left_shift_bits = bit_offset;
366#elif defined(__LITTLE_ENDIAN_BITFIELD)
367 left_shift_bits = 128 - bits_to_copy;
368#else
369#error neither big nor little endian
370#endif
371 right_shift_bits = 128 - nr_bits;
372
373 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
374 btf_int128_print(jw, data: print_num, is_plain_text);
375}
376
377
378static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
379 const void *data, json_writer_t *jw,
380 bool is_plain_text)
381{
382 int nr_bits = BTF_INT_BITS(int_type);
383 int total_bits_offset;
384
385 /* bits_offset is at most 7.
386 * BTF_INT_OFFSET() cannot exceed 128 bits.
387 */
388 total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
389 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
390 bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
391 btf_dumper_bitfield(nr_bits, bit_offset, data, jw,
392 is_plain_text);
393}
394
395static int btf_dumper_int(const struct btf_type *t, __u8 bit_offset,
396 const void *data, json_writer_t *jw,
397 bool is_plain_text)
398{
399 __u32 *int_type;
400 __u32 nr_bits;
401
402 int_type = (__u32 *)(t + 1);
403 nr_bits = BTF_INT_BITS(*int_type);
404 /* if this is bit field */
405 if (bit_offset || BTF_INT_OFFSET(*int_type) ||
406 BITS_PER_BYTE_MASKED(nr_bits)) {
407 btf_dumper_int_bits(int_type: *int_type, bit_offset, data, jw,
408 is_plain_text);
409 return 0;
410 }
411
412 if (nr_bits == 128) {
413 btf_int128_print(jw, data, is_plain_text);
414 return 0;
415 }
416
417 switch (BTF_INT_ENCODING(*int_type)) {
418 case 0:
419 if (BTF_INT_BITS(*int_type) == 64)
420 jsonw_printf(self: jw, fmt: "%llu", *(__u64 *)data);
421 else if (BTF_INT_BITS(*int_type) == 32)
422 jsonw_printf(self: jw, fmt: "%u", *(__u32 *)data);
423 else if (BTF_INT_BITS(*int_type) == 16)
424 jsonw_printf(self: jw, fmt: "%hu", *(__u16 *)data);
425 else if (BTF_INT_BITS(*int_type) == 8)
426 jsonw_printf(self: jw, fmt: "%hhu", *(__u8 *)data);
427 else
428 btf_dumper_int_bits(int_type: *int_type, bit_offset, data, jw,
429 is_plain_text);
430 break;
431 case BTF_INT_SIGNED:
432 if (BTF_INT_BITS(*int_type) == 64)
433 jsonw_printf(self: jw, fmt: "%lld", *(long long *)data);
434 else if (BTF_INT_BITS(*int_type) == 32)
435 jsonw_printf(self: jw, fmt: "%d", *(int *)data);
436 else if (BTF_INT_BITS(*int_type) == 16)
437 jsonw_printf(self: jw, fmt: "%hd", *(short *)data);
438 else if (BTF_INT_BITS(*int_type) == 8)
439 jsonw_printf(self: jw, fmt: "%hhd", *(char *)data);
440 else
441 btf_dumper_int_bits(int_type: *int_type, bit_offset, data, jw,
442 is_plain_text);
443 break;
444 case BTF_INT_CHAR:
445 if (isprint(*(char *)data))
446 jsonw_printf(self: jw, fmt: "\"%c\"", *(char *)data);
447 else
448 if (is_plain_text)
449 jsonw_printf(self: jw, fmt: "0x%hhx", *(char *)data);
450 else
451 jsonw_printf(self: jw, fmt: "\"\\u00%02hhx\"",
452 *(char *)data);
453 break;
454 case BTF_INT_BOOL:
455 jsonw_bool(self: jw, value: *(bool *)data);
456 break;
457 default:
458 /* shouldn't happen */
459 return -EINVAL;
460 }
461
462 return 0;
463}
464
465static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
466 const void *data)
467{
468 const struct btf_type *t;
469 struct btf_member *m;
470 const void *data_off;
471 int kind_flag;
472 int ret = 0;
473 int i, vlen;
474
475 t = btf__type_by_id(d->btf, type_id);
476 if (!t)
477 return -EINVAL;
478
479 kind_flag = BTF_INFO_KFLAG(t->info);
480 vlen = BTF_INFO_VLEN(t->info);
481 jsonw_start_object(self: d->jw);
482 m = (struct btf_member *)(t + 1);
483
484 for (i = 0; i < vlen; i++) {
485 __u32 bit_offset = m[i].offset;
486 __u32 bitfield_size = 0;
487
488 if (kind_flag) {
489 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(bit_offset);
490 bit_offset = BTF_MEMBER_BIT_OFFSET(bit_offset);
491 }
492
493 jsonw_name(self: d->jw, name: btf__name_by_offset(d->btf, m[i].name_off));
494 data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
495 if (bitfield_size) {
496 btf_dumper_bitfield(nr_bits: bitfield_size,
497 BITS_PER_BYTE_MASKED(bit_offset),
498 data: data_off, jw: d->jw, is_plain_text: d->is_plain_text);
499 } else {
500 ret = btf_dumper_do_type(d, type_id: m[i].type,
501 BITS_PER_BYTE_MASKED(bit_offset),
502 data: data_off);
503 if (ret)
504 break;
505 }
506 }
507
508 jsonw_end_object(self: d->jw);
509
510 return ret;
511}
512
513static int btf_dumper_var(const struct btf_dumper *d, __u32 type_id,
514 __u8 bit_offset, const void *data)
515{
516 const struct btf_type *t = btf__type_by_id(d->btf, type_id);
517 int ret;
518
519 jsonw_start_object(self: d->jw);
520 jsonw_name(self: d->jw, name: btf__name_by_offset(d->btf, t->name_off));
521 ret = btf_dumper_do_type(d, type_id: t->type, bit_offset, data);
522 jsonw_end_object(self: d->jw);
523
524 return ret;
525}
526
527static int btf_dumper_datasec(const struct btf_dumper *d, __u32 type_id,
528 const void *data)
529{
530 struct btf_var_secinfo *vsi;
531 const struct btf_type *t;
532 int ret = 0, i, vlen;
533
534 t = btf__type_by_id(d->btf, type_id);
535 if (!t)
536 return -EINVAL;
537
538 vlen = BTF_INFO_VLEN(t->info);
539 vsi = (struct btf_var_secinfo *)(t + 1);
540
541 jsonw_start_object(self: d->jw);
542 jsonw_name(self: d->jw, name: btf__name_by_offset(d->btf, t->name_off));
543 jsonw_start_array(self: d->jw);
544 for (i = 0; i < vlen; i++) {
545 ret = btf_dumper_do_type(d, type_id: vsi[i].type, bit_offset: 0, data: data + vsi[i].offset);
546 if (ret)
547 break;
548 }
549 jsonw_end_array(self: d->jw);
550 jsonw_end_object(self: d->jw);
551
552 return ret;
553}
554
555static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
556 __u8 bit_offset, const void *data)
557{
558 const struct btf_type *t = btf__type_by_id(d->btf, type_id);
559
560 switch (BTF_INFO_KIND(t->info)) {
561 case BTF_KIND_INT:
562 return btf_dumper_int(t, bit_offset, data, jw: d->jw,
563 is_plain_text: d->is_plain_text);
564 case BTF_KIND_STRUCT:
565 case BTF_KIND_UNION:
566 return btf_dumper_struct(d, type_id, data);
567 case BTF_KIND_ARRAY:
568 return btf_dumper_array(d, type_id, data);
569 case BTF_KIND_ENUM:
570 return btf_dumper_enum(d, t, data);
571 case BTF_KIND_ENUM64:
572 return btf_dumper_enum64(d, t, data);
573 case BTF_KIND_PTR:
574 btf_dumper_ptr(d, t, data);
575 return 0;
576 case BTF_KIND_UNKN:
577 jsonw_printf(self: d->jw, fmt: "(unknown)");
578 return 0;
579 case BTF_KIND_FWD:
580 /* map key or value can't be forward */
581 jsonw_printf(self: d->jw, fmt: "(fwd-kind-invalid)");
582 return -EINVAL;
583 case BTF_KIND_TYPEDEF:
584 case BTF_KIND_VOLATILE:
585 case BTF_KIND_CONST:
586 case BTF_KIND_RESTRICT:
587 return btf_dumper_modifier(d, type_id, bit_offset, data);
588 case BTF_KIND_VAR:
589 return btf_dumper_var(d, type_id, bit_offset, data);
590 case BTF_KIND_DATASEC:
591 return btf_dumper_datasec(d, type_id, data);
592 default:
593 jsonw_printf(self: d->jw, fmt: "(unsupported-kind");
594 return -EINVAL;
595 }
596}
597
598int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,
599 const void *data)
600{
601 return btf_dumper_do_type(d, type_id, bit_offset: 0, data);
602}
603
604#define BTF_PRINT_ARG(...) \
605 do { \
606 pos += snprintf(func_sig + pos, size - pos, \
607 __VA_ARGS__); \
608 if (pos >= size) \
609 return -1; \
610 } while (0)
611#define BTF_PRINT_TYPE(type) \
612 do { \
613 pos = __btf_dumper_type_only(btf, type, func_sig, \
614 pos, size); \
615 if (pos == -1) \
616 return -1; \
617 } while (0)
618
619static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
620 char *func_sig, int pos, int size)
621{
622 const struct btf_type *proto_type;
623 const struct btf_array *array;
624 const struct btf_var *var;
625 const struct btf_type *t;
626
627 if (!type_id) {
628 BTF_PRINT_ARG("void ");
629 return pos;
630 }
631
632 t = btf__type_by_id(btf, type_id);
633
634 switch (BTF_INFO_KIND(t->info)) {
635 case BTF_KIND_INT:
636 case BTF_KIND_TYPEDEF:
637 case BTF_KIND_FLOAT:
638 BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));
639 break;
640 case BTF_KIND_STRUCT:
641 BTF_PRINT_ARG("struct %s ",
642 btf__name_by_offset(btf, t->name_off));
643 break;
644 case BTF_KIND_UNION:
645 BTF_PRINT_ARG("union %s ",
646 btf__name_by_offset(btf, t->name_off));
647 break;
648 case BTF_KIND_ENUM:
649 case BTF_KIND_ENUM64:
650 BTF_PRINT_ARG("enum %s ",
651 btf__name_by_offset(btf, t->name_off));
652 break;
653 case BTF_KIND_ARRAY:
654 array = (struct btf_array *)(t + 1);
655 BTF_PRINT_TYPE(array->type);
656 BTF_PRINT_ARG("[%d]", array->nelems);
657 break;
658 case BTF_KIND_PTR:
659 BTF_PRINT_TYPE(t->type);
660 BTF_PRINT_ARG("* ");
661 break;
662 case BTF_KIND_FWD:
663 BTF_PRINT_ARG("%s %s ",
664 BTF_INFO_KFLAG(t->info) ? "union" : "struct",
665 btf__name_by_offset(btf, t->name_off));
666 break;
667 case BTF_KIND_VOLATILE:
668 BTF_PRINT_ARG("volatile ");
669 BTF_PRINT_TYPE(t->type);
670 break;
671 case BTF_KIND_CONST:
672 BTF_PRINT_ARG("const ");
673 BTF_PRINT_TYPE(t->type);
674 break;
675 case BTF_KIND_RESTRICT:
676 BTF_PRINT_ARG("restrict ");
677 BTF_PRINT_TYPE(t->type);
678 break;
679 case BTF_KIND_FUNC_PROTO:
680 pos = btf_dump_func(btf, func_sig, func_proto: t, NULL, pos, size);
681 if (pos == -1)
682 return -1;
683 break;
684 case BTF_KIND_FUNC:
685 proto_type = btf__type_by_id(btf, t->type);
686 pos = btf_dump_func(btf, func_sig, func_proto: proto_type, func: t, pos, size);
687 if (pos == -1)
688 return -1;
689 break;
690 case BTF_KIND_VAR:
691 var = (struct btf_var *)(t + 1);
692 if (var->linkage == BTF_VAR_STATIC)
693 BTF_PRINT_ARG("static ");
694 BTF_PRINT_TYPE(t->type);
695 BTF_PRINT_ARG(" %s",
696 btf__name_by_offset(btf, t->name_off));
697 break;
698 case BTF_KIND_DATASEC:
699 BTF_PRINT_ARG("section (\"%s\") ",
700 btf__name_by_offset(btf, t->name_off));
701 break;
702 case BTF_KIND_UNKN:
703 default:
704 return -1;
705 }
706
707 return pos;
708}
709
710static int btf_dump_func(const struct btf *btf, char *func_sig,
711 const struct btf_type *func_proto,
712 const struct btf_type *func, int pos, int size)
713{
714 int i, vlen;
715
716 BTF_PRINT_TYPE(func_proto->type);
717 if (func)
718 BTF_PRINT_ARG("%s(", btf__name_by_offset(btf, func->name_off));
719 else
720 BTF_PRINT_ARG("(");
721 vlen = BTF_INFO_VLEN(func_proto->info);
722 for (i = 0; i < vlen; i++) {
723 struct btf_param *arg = &((struct btf_param *)(func_proto + 1))[i];
724
725 if (i)
726 BTF_PRINT_ARG(", ");
727 if (arg->type) {
728 BTF_PRINT_TYPE(arg->type);
729 if (arg->name_off)
730 BTF_PRINT_ARG("%s",
731 btf__name_by_offset(btf, arg->name_off));
732 else if (pos && func_sig[pos - 1] == ' ')
733 /* Remove unnecessary space for
734 * FUNC_PROTO that does not have
735 * arg->name_off
736 */
737 func_sig[--pos] = '\0';
738 } else {
739 BTF_PRINT_ARG("...");
740 }
741 }
742 BTF_PRINT_ARG(")");
743
744 return pos;
745}
746
747void btf_dumper_type_only(const struct btf *btf, __u32 type_id, char *func_sig,
748 int size)
749{
750 int err;
751
752 func_sig[0] = '\0';
753 if (!btf)
754 return;
755
756 err = __btf_dumper_type_only(btf, type_id, func_sig, pos: 0, size);
757 if (err < 0)
758 func_sig[0] = '\0';
759}
760
761static const char *ltrim(const char *s)
762{
763 while (isspace(*s))
764 s++;
765
766 return s;
767}
768
769void btf_dump_linfo_plain(const struct btf *btf,
770 const struct bpf_line_info *linfo,
771 const char *prefix, bool linum)
772{
773 const char *line = btf__name_by_offset(btf, linfo->line_off);
774
775 if (!line)
776 return;
777 line = ltrim(s: line);
778
779 if (!prefix)
780 prefix = "";
781
782 if (linum) {
783 const char *file = btf__name_by_offset(btf, linfo->file_name_off);
784
785 /* More forgiving on file because linum option is
786 * expected to provide more info than the already
787 * available src line.
788 */
789 if (!file)
790 file = "";
791
792 printf("%s%s [file:%s line_num:%u line_col:%u]\n",
793 prefix, line, file,
794 BPF_LINE_INFO_LINE_NUM(linfo->line_col),
795 BPF_LINE_INFO_LINE_COL(linfo->line_col));
796 } else {
797 printf("%s%s\n", prefix, line);
798 }
799}
800
801void btf_dump_linfo_json(const struct btf *btf,
802 const struct bpf_line_info *linfo, bool linum)
803{
804 const char *line = btf__name_by_offset(btf, linfo->line_off);
805
806 if (line)
807 jsonw_string_field(self: json_wtr, prop: "src", val: ltrim(s: line));
808
809 if (linum) {
810 const char *file = btf__name_by_offset(btf, linfo->file_name_off);
811
812 if (file)
813 jsonw_string_field(self: json_wtr, prop: "file", val: file);
814
815 if (BPF_LINE_INFO_LINE_NUM(linfo->line_col))
816 jsonw_int_field(self: json_wtr, prop: "line_num",
817 BPF_LINE_INFO_LINE_NUM(linfo->line_col));
818
819 if (BPF_LINE_INFO_LINE_COL(linfo->line_col))
820 jsonw_int_field(self: json_wtr, prop: "line_col",
821 BPF_LINE_INFO_LINE_COL(linfo->line_col));
822 }
823}
824
825static void dotlabel_puts(const char *s)
826{
827 for (; *s; ++s) {
828 switch (*s) {
829 case '\\':
830 case '"':
831 case '{':
832 case '}':
833 case '<':
834 case '>':
835 case '|':
836 case ' ':
837 putchar('\\');
838 fallthrough;
839 default:
840 putchar(*s);
841 }
842 }
843}
844
845static const char *shorten_path(const char *path)
846{
847 const unsigned int MAX_PATH_LEN = 32;
848 size_t len = strlen(path);
849 const char *shortpath;
850
851 if (len <= MAX_PATH_LEN)
852 return path;
853
854 /* Search for last '/' under the MAX_PATH_LEN limit */
855 shortpath = strchr(path + len - MAX_PATH_LEN, '/');
856 if (shortpath) {
857 if (shortpath < path + strlen("..."))
858 /* We removed a very short prefix, e.g. "/w", and we'll
859 * make the path longer by prefixing with the ellipsis.
860 * Not worth it, keep initial path.
861 */
862 return path;
863 return shortpath;
864 }
865
866 /* File base name length is > MAX_PATH_LEN, search for last '/' */
867 shortpath = strrchr(path, '/');
868 if (shortpath)
869 return shortpath;
870
871 return path;
872}
873
874void btf_dump_linfo_dotlabel(const struct btf *btf,
875 const struct bpf_line_info *linfo, bool linum)
876{
877 const char *line = btf__name_by_offset(btf, linfo->line_off);
878
879 if (!line || !strlen(line))
880 return;
881 line = ltrim(s: line);
882
883 if (linum) {
884 const char *file = btf__name_by_offset(btf, linfo->file_name_off);
885 const char *shortfile;
886
887 /* More forgiving on file because linum option is
888 * expected to provide more info than the already
889 * available src line.
890 */
891 if (!file)
892 shortfile = "";
893 else
894 shortfile = shorten_path(path: file);
895
896 printf("; [%s", shortfile > file ? "..." : "");
897 dotlabel_puts(s: shortfile);
898 printf(" line:%u col:%u]\\l\\\n",
899 BPF_LINE_INFO_LINE_NUM(linfo->line_col),
900 BPF_LINE_INFO_LINE_COL(linfo->line_col));
901 }
902
903 printf("; ");
904 dotlabel_puts(s: line);
905 printf("\\l\\\n");
906}
907

source code of linux/tools/bpf/bpftool/btf_dumper.c