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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 <asm/byteorder.h>
8#include <linux/bitops.h>
9#include <linux/btf.h>
10#include <linux/err.h>
11
12#include "btf.h"
13#include "json_writer.h"
14#include "main.h"
15
16#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
17#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
18#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
19#define BITS_ROUNDUP_BYTES(bits) \
20 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
21
22static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
23 __u8 bit_offset, const void *data);
24
25static void btf_dumper_ptr(const void *data, json_writer_t *jw,
26 bool is_plain_text)
27{
28 if (is_plain_text)
29 jsonw_printf(jw, "%p", data);
30 else
31 jsonw_printf(jw, "%lu", *(unsigned long *)data);
32}
33
34static int btf_dumper_modifier(const struct btf_dumper *d, __u32 type_id,
35 __u8 bit_offset, const void *data)
36{
37 int actual_type_id;
38
39 actual_type_id = btf__resolve_type(d->btf, type_id);
40 if (actual_type_id < 0)
41 return actual_type_id;
42
43 return btf_dumper_do_type(d, actual_type_id, bit_offset, data);
44}
45
46static void btf_dumper_enum(const void *data, json_writer_t *jw)
47{
48 jsonw_printf(jw, "%d", *(int *)data);
49}
50
51static int btf_dumper_array(const struct btf_dumper *d, __u32 type_id,
52 const void *data)
53{
54 const struct btf_type *t = btf__type_by_id(d->btf, type_id);
55 struct btf_array *arr = (struct btf_array *)(t + 1);
56 long long elem_size;
57 int ret = 0;
58 __u32 i;
59
60 elem_size = btf__resolve_size(d->btf, arr->type);
61 if (elem_size < 0)
62 return elem_size;
63
64 jsonw_start_array(d->jw);
65 for (i = 0; i < arr->nelems; i++) {
66 ret = btf_dumper_do_type(d, arr->type, 0,
67 data + i * elem_size);
68 if (ret)
69 break;
70 }
71
72 jsonw_end_array(d->jw);
73 return ret;
74}
75
76static void btf_int128_print(json_writer_t *jw, const void *data,
77 bool is_plain_text)
78{
79 /* data points to a __int128 number.
80 * Suppose
81 * int128_num = *(__int128 *)data;
82 * The below formulas shows what upper_num and lower_num represents:
83 * upper_num = int128_num >> 64;
84 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
85 */
86 __u64 upper_num, lower_num;
87
88#ifdef __BIG_ENDIAN_BITFIELD
89 upper_num = *(__u64 *)data;
90 lower_num = *(__u64 *)(data + 8);
91#else
92 upper_num = *(__u64 *)(data + 8);
93 lower_num = *(__u64 *)data;
94#endif
95
96 if (is_plain_text) {
97 if (upper_num == 0)
98 jsonw_printf(jw, "0x%llx", lower_num);
99 else
100 jsonw_printf(jw, "0x%llx%016llx", upper_num, lower_num);
101 } else {
102 if (upper_num == 0)
103 jsonw_printf(jw, "\"0x%llx\"", lower_num);
104 else
105 jsonw_printf(jw, "\"0x%llx%016llx\"", upper_num, lower_num);
106 }
107}
108
109static void btf_int128_shift(__u64 *print_num, u16 left_shift_bits,
110 u16 right_shift_bits)
111{
112 __u64 upper_num, lower_num;
113
114#ifdef __BIG_ENDIAN_BITFIELD
115 upper_num = print_num[0];
116 lower_num = print_num[1];
117#else
118 upper_num = print_num[1];
119 lower_num = print_num[0];
120#endif
121
122 /* shake out un-needed bits by shift/or operations */
123 if (left_shift_bits >= 64) {
124 upper_num = lower_num << (left_shift_bits - 64);
125 lower_num = 0;
126 } else {
127 upper_num = (upper_num << left_shift_bits) |
128 (lower_num >> (64 - left_shift_bits));
129 lower_num = lower_num << left_shift_bits;
130 }
131
132 if (right_shift_bits >= 64) {
133 lower_num = upper_num >> (right_shift_bits - 64);
134 upper_num = 0;
135 } else {
136 lower_num = (lower_num >> right_shift_bits) |
137 (upper_num << (64 - right_shift_bits));
138 upper_num = upper_num >> right_shift_bits;
139 }
140
141#ifdef __BIG_ENDIAN_BITFIELD
142 print_num[0] = upper_num;
143 print_num[1] = lower_num;
144#else
145 print_num[0] = lower_num;
146 print_num[1] = upper_num;
147#endif
148}
149
150static void btf_dumper_bitfield(__u32 nr_bits, __u8 bit_offset,
151 const void *data, json_writer_t *jw,
152 bool is_plain_text)
153{
154 int left_shift_bits, right_shift_bits;
155 __u64 print_num[2] = {};
156 int bytes_to_copy;
157 int bits_to_copy;
158
159 bits_to_copy = bit_offset + nr_bits;
160 bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
161
162 memcpy(print_num, data, bytes_to_copy);
163#if defined(__BIG_ENDIAN_BITFIELD)
164 left_shift_bits = bit_offset;
165#elif defined(__LITTLE_ENDIAN_BITFIELD)
166 left_shift_bits = 128 - bits_to_copy;
167#else
168#error neither big nor little endian
169#endif
170 right_shift_bits = 128 - nr_bits;
171
172 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
173 btf_int128_print(jw, print_num, is_plain_text);
174}
175
176
177static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
178 const void *data, json_writer_t *jw,
179 bool is_plain_text)
180{
181 int nr_bits = BTF_INT_BITS(int_type);
182 int total_bits_offset;
183
184 /* bits_offset is at most 7.
185 * BTF_INT_OFFSET() cannot exceed 128 bits.
186 */
187 total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
188 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
189 bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
190 btf_dumper_bitfield(nr_bits, bit_offset, data, jw,
191 is_plain_text);
192}
193
194static int btf_dumper_int(const struct btf_type *t, __u8 bit_offset,
195 const void *data, json_writer_t *jw,
196 bool is_plain_text)
197{
198 __u32 *int_type;
199 __u32 nr_bits;
200
201 int_type = (__u32 *)(t + 1);
202 nr_bits = BTF_INT_BITS(*int_type);
203 /* if this is bit field */
204 if (bit_offset || BTF_INT_OFFSET(*int_type) ||
205 BITS_PER_BYTE_MASKED(nr_bits)) {
206 btf_dumper_int_bits(*int_type, bit_offset, data, jw,
207 is_plain_text);
208 return 0;
209 }
210
211 if (nr_bits == 128) {
212 btf_int128_print(jw, data, is_plain_text);
213 return 0;
214 }
215
216 switch (BTF_INT_ENCODING(*int_type)) {
217 case 0:
218 if (BTF_INT_BITS(*int_type) == 64)
219 jsonw_printf(jw, "%llu", *(__u64 *)data);
220 else if (BTF_INT_BITS(*int_type) == 32)
221 jsonw_printf(jw, "%u", *(__u32 *)data);
222 else if (BTF_INT_BITS(*int_type) == 16)
223 jsonw_printf(jw, "%hu", *(__u16 *)data);
224 else if (BTF_INT_BITS(*int_type) == 8)
225 jsonw_printf(jw, "%hhu", *(__u8 *)data);
226 else
227 btf_dumper_int_bits(*int_type, bit_offset, data, jw,
228 is_plain_text);
229 break;
230 case BTF_INT_SIGNED:
231 if (BTF_INT_BITS(*int_type) == 64)
232 jsonw_printf(jw, "%lld", *(long long *)data);
233 else if (BTF_INT_BITS(*int_type) == 32)
234 jsonw_printf(jw, "%d", *(int *)data);
235 else if (BTF_INT_BITS(*int_type) == 16)
236 jsonw_printf(jw, "%hd", *(short *)data);
237 else if (BTF_INT_BITS(*int_type) == 8)
238 jsonw_printf(jw, "%hhd", *(char *)data);
239 else
240 btf_dumper_int_bits(*int_type, bit_offset, data, jw,
241 is_plain_text);
242 break;
243 case BTF_INT_CHAR:
244 if (isprint(*(char *)data))
245 jsonw_printf(jw, "\"%c\"", *(char *)data);
246 else
247 if (is_plain_text)
248 jsonw_printf(jw, "0x%hhx", *(char *)data);
249 else
250 jsonw_printf(jw, "\"\\u00%02hhx\"",
251 *(char *)data);
252 break;
253 case BTF_INT_BOOL:
254 jsonw_bool(jw, *(int *)data);
255 break;
256 default:
257 /* shouldn't happen */
258 return -EINVAL;
259 }
260
261 return 0;
262}
263
264static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
265 const void *data)
266{
267 const struct btf_type *t;
268 struct btf_member *m;
269 const void *data_off;
270 int kind_flag;
271 int ret = 0;
272 int i, vlen;
273
274 t = btf__type_by_id(d->btf, type_id);
275 if (!t)
276 return -EINVAL;
277
278 kind_flag = BTF_INFO_KFLAG(t->info);
279 vlen = BTF_INFO_VLEN(t->info);
280 jsonw_start_object(d->jw);
281 m = (struct btf_member *)(t + 1);
282
283 for (i = 0; i < vlen; i++) {
284 __u32 bit_offset = m[i].offset;
285 __u32 bitfield_size = 0;
286
287 if (kind_flag) {
288 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(bit_offset);
289 bit_offset = BTF_MEMBER_BIT_OFFSET(bit_offset);
290 }
291
292 jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off));
293 data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
294 if (bitfield_size) {
295 btf_dumper_bitfield(bitfield_size,
296 BITS_PER_BYTE_MASKED(bit_offset),
297 data_off, d->jw, d->is_plain_text);
298 } else {
299 ret = btf_dumper_do_type(d, m[i].type,
300 BITS_PER_BYTE_MASKED(bit_offset),
301 data_off);
302 if (ret)
303 break;
304 }
305 }
306
307 jsonw_end_object(d->jw);
308
309 return ret;
310}
311
312static int btf_dumper_var(const struct btf_dumper *d, __u32 type_id,
313 __u8 bit_offset, const void *data)
314{
315 const struct btf_type *t = btf__type_by_id(d->btf, type_id);
316 int ret;
317
318 jsonw_start_object(d->jw);
319 jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
320 ret = btf_dumper_do_type(d, t->type, bit_offset, data);
321 jsonw_end_object(d->jw);
322
323 return ret;
324}
325
326static int btf_dumper_datasec(const struct btf_dumper *d, __u32 type_id,
327 const void *data)
328{
329 struct btf_var_secinfo *vsi;
330 const struct btf_type *t;
331 int ret = 0, i, vlen;
332
333 t = btf__type_by_id(d->btf, type_id);
334 if (!t)
335 return -EINVAL;
336
337 vlen = BTF_INFO_VLEN(t->info);
338 vsi = (struct btf_var_secinfo *)(t + 1);
339
340 jsonw_start_object(d->jw);
341 jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
342 jsonw_start_array(d->jw);
343 for (i = 0; i < vlen; i++) {
344 ret = btf_dumper_do_type(d, vsi[i].type, 0, data + vsi[i].offset);
345 if (ret)
346 break;
347 }
348 jsonw_end_array(d->jw);
349 jsonw_end_object(d->jw);
350
351 return ret;
352}
353
354static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
355 __u8 bit_offset, const void *data)
356{
357 const struct btf_type *t = btf__type_by_id(d->btf, type_id);
358
359 switch (BTF_INFO_KIND(t->info)) {
360 case BTF_KIND_INT:
361 return btf_dumper_int(t, bit_offset, data, d->jw,
362 d->is_plain_text);
363 case BTF_KIND_STRUCT:
364 case BTF_KIND_UNION:
365 return btf_dumper_struct(d, type_id, data);
366 case BTF_KIND_ARRAY:
367 return btf_dumper_array(d, type_id, data);
368 case BTF_KIND_ENUM:
369 btf_dumper_enum(data, d->jw);
370 return 0;
371 case BTF_KIND_PTR:
372 btf_dumper_ptr(data, d->jw, d->is_plain_text);
373 return 0;
374 case BTF_KIND_UNKN:
375 jsonw_printf(d->jw, "(unknown)");
376 return 0;
377 case BTF_KIND_FWD:
378 /* map key or value can't be forward */
379 jsonw_printf(d->jw, "(fwd-kind-invalid)");
380 return -EINVAL;
381 case BTF_KIND_TYPEDEF:
382 case BTF_KIND_VOLATILE:
383 case BTF_KIND_CONST:
384 case BTF_KIND_RESTRICT:
385 return btf_dumper_modifier(d, type_id, bit_offset, data);
386 case BTF_KIND_VAR:
387 return btf_dumper_var(d, type_id, bit_offset, data);
388 case BTF_KIND_DATASEC:
389 return btf_dumper_datasec(d, type_id, data);
390 default:
391 jsonw_printf(d->jw, "(unsupported-kind");
392 return -EINVAL;
393 }
394}
395
396int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,
397 const void *data)
398{
399 return btf_dumper_do_type(d, type_id, 0, data);
400}
401
402#define BTF_PRINT_ARG(...) \
403 do { \
404 pos += snprintf(func_sig + pos, size - pos, \
405 __VA_ARGS__); \
406 if (pos >= size) \
407 return -1; \
408 } while (0)
409#define BTF_PRINT_TYPE(type) \
410 do { \
411 pos = __btf_dumper_type_only(btf, type, func_sig, \
412 pos, size); \
413 if (pos == -1) \
414 return -1; \
415 } while (0)
416
417static int btf_dump_func(const struct btf *btf, char *func_sig,
418 const struct btf_type *func_proto,
419 const struct btf_type *func, int pos, int size);
420
421static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
422 char *func_sig, int pos, int size)
423{
424 const struct btf_type *proto_type;
425 const struct btf_array *array;
426 const struct btf_var *var;
427 const struct btf_type *t;
428
429 if (!type_id) {
430 BTF_PRINT_ARG("void ");
431 return pos;
432 }
433
434 t = btf__type_by_id(btf, type_id);
435
436 switch (BTF_INFO_KIND(t->info)) {
437 case BTF_KIND_INT:
438 case BTF_KIND_TYPEDEF:
439 BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));
440 break;
441 case BTF_KIND_STRUCT:
442 BTF_PRINT_ARG("struct %s ",
443 btf__name_by_offset(btf, t->name_off));
444 break;
445 case BTF_KIND_UNION:
446 BTF_PRINT_ARG("union %s ",
447 btf__name_by_offset(btf, t->name_off));
448 break;
449 case BTF_KIND_ENUM:
450 BTF_PRINT_ARG("enum %s ",
451 btf__name_by_offset(btf, t->name_off));
452 break;
453 case BTF_KIND_ARRAY:
454 array = (struct btf_array *)(t + 1);
455 BTF_PRINT_TYPE(array->type);
456 BTF_PRINT_ARG("[%d]", array->nelems);
457 break;
458 case BTF_KIND_PTR:
459 BTF_PRINT_TYPE(t->type);
460 BTF_PRINT_ARG("* ");
461 break;
462 case BTF_KIND_FWD:
463 BTF_PRINT_ARG("%s %s ",
464 BTF_INFO_KFLAG(t->info) ? "union" : "struct",
465 btf__name_by_offset(btf, t->name_off));
466 break;
467 case BTF_KIND_VOLATILE:
468 BTF_PRINT_ARG("volatile ");
469 BTF_PRINT_TYPE(t->type);
470 break;
471 case BTF_KIND_CONST:
472 BTF_PRINT_ARG("const ");
473 BTF_PRINT_TYPE(t->type);
474 break;
475 case BTF_KIND_RESTRICT:
476 BTF_PRINT_ARG("restrict ");
477 BTF_PRINT_TYPE(t->type);
478 break;
479 case BTF_KIND_FUNC_PROTO:
480 pos = btf_dump_func(btf, func_sig, t, NULL, pos, size);
481 if (pos == -1)
482 return -1;
483 break;
484 case BTF_KIND_FUNC:
485 proto_type = btf__type_by_id(btf, t->type);
486 pos = btf_dump_func(btf, func_sig, proto_type, t, pos, size);
487 if (pos == -1)
488 return -1;
489 break;
490 case BTF_KIND_VAR:
491 var = (struct btf_var *)(t + 1);
492 if (var->linkage == BTF_VAR_STATIC)
493 BTF_PRINT_ARG("static ");
494 BTF_PRINT_TYPE(t->type);
495 BTF_PRINT_ARG(" %s",
496 btf__name_by_offset(btf, t->name_off));
497 break;
498 case BTF_KIND_DATASEC:
499 BTF_PRINT_ARG("section (\"%s\") ",
500 btf__name_by_offset(btf, t->name_off));
501 break;
502 case BTF_KIND_UNKN:
503 default:
504 return -1;
505 }
506
507 return pos;
508}
509
510static int btf_dump_func(const struct btf *btf, char *func_sig,
511 const struct btf_type *func_proto,
512 const struct btf_type *func, int pos, int size)
513{
514 int i, vlen;
515
516 BTF_PRINT_TYPE(func_proto->type);
517 if (func)
518 BTF_PRINT_ARG("%s(", btf__name_by_offset(btf, func->name_off));
519 else
520 BTF_PRINT_ARG("(");
521 vlen = BTF_INFO_VLEN(func_proto->info);
522 for (i = 0; i < vlen; i++) {
523 struct btf_param *arg = &((struct btf_param *)(func_proto + 1))[i];
524
525 if (i)
526 BTF_PRINT_ARG(", ");
527 if (arg->type) {
528 BTF_PRINT_TYPE(arg->type);
529 BTF_PRINT_ARG("%s",
530 btf__name_by_offset(btf, arg->name_off));
531 } else {
532 BTF_PRINT_ARG("...");
533 }
534 }
535 BTF_PRINT_ARG(")");
536
537 return pos;
538}
539
540void btf_dumper_type_only(const struct btf *btf, __u32 type_id, char *func_sig,
541 int size)
542{
543 int err;
544
545 func_sig[0] = '\0';
546 if (!btf)
547 return;
548
549 err = __btf_dumper_type_only(btf, type_id, func_sig, 0, size);
550 if (err < 0)
551 func_sig[0] = '\0';
552}
553
554static const char *ltrim(const char *s)
555{
556 while (isspace(*s))
557 s++;
558
559 return s;
560}
561
562void btf_dump_linfo_plain(const struct btf *btf,
563 const struct bpf_line_info *linfo,
564 const char *prefix, bool linum)
565{
566 const char *line = btf__name_by_offset(btf, linfo->line_off);
567
568 if (!line)
569 return;
570 line = ltrim(line);
571
572 if (!prefix)
573 prefix = "";
574
575 if (linum) {
576 const char *file = btf__name_by_offset(btf, linfo->file_name_off);
577
578 /* More forgiving on file because linum option is
579 * expected to provide more info than the already
580 * available src line.
581 */
582 if (!file)
583 file = "";
584
585 printf("%s%s [file:%s line_num:%u line_col:%u]\n",
586 prefix, line, file,
587 BPF_LINE_INFO_LINE_NUM(linfo->line_col),
588 BPF_LINE_INFO_LINE_COL(linfo->line_col));
589 } else {
590 printf("%s%s\n", prefix, line);
591 }
592}
593
594void btf_dump_linfo_json(const struct btf *btf,
595 const struct bpf_line_info *linfo, bool linum)
596{
597 const char *line = btf__name_by_offset(btf, linfo->line_off);
598
599 if (line)
600 jsonw_string_field(json_wtr, "src", ltrim(line));
601
602 if (linum) {
603 const char *file = btf__name_by_offset(btf, linfo->file_name_off);
604
605 if (file)
606 jsonw_string_field(json_wtr, "file", file);
607
608 if (BPF_LINE_INFO_LINE_NUM(linfo->line_col))
609 jsonw_int_field(json_wtr, "line_num",
610 BPF_LINE_INFO_LINE_NUM(linfo->line_col));
611
612 if (BPF_LINE_INFO_LINE_COL(linfo->line_col))
613 jsonw_int_field(json_wtr, "line_col",
614 BPF_LINE_INFO_LINE_COL(linfo->line_col));
615 }
616}