1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2018 Netronome Systems, Inc. */
3
4 #ifndef _GNU_SOURCE
5 #define _GNU_SOURCE
6 #endif
7 #include <stdarg.h>
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <string.h>
11 #include <sys/types.h>
12 #include <bpf/libbpf.h>
13 #include <bpf/libbpf_internal.h>
14
15 #include "disasm.h"
16 #include "json_writer.h"
17 #include "main.h"
18 #include "xlated_dumper.h"
19
20 static int kernel_syms_cmp(const void *sym_a, const void *sym_b)
21 {
22 return ((struct kernel_sym *)sym_a)->address -
23 ((struct kernel_sym *)sym_b)->address;
24 }
25
26 void kernel_syms_load(struct dump_data *dd)
27 {
28 struct kernel_sym *sym;
29 char buff[256];
30 void *tmp, *address;
31 FILE *fp;
32
33 fp = fopen("/proc/kallsyms", "r");
34 if (!fp)
35 return;
36
37 while (fgets(buff, sizeof(buff), fp)) {
38 tmp = libbpf_reallocarray(dd->sym_mapping, dd->sym_count + 1,
39 sizeof(*dd->sym_mapping));
40 if (!tmp) {
41 out:
42 free(dd->sym_mapping);
43 dd->sym_mapping = NULL;
44 fclose(fp);
45 return;
46 }
47 dd->sym_mapping = tmp;
48 sym = &dd->sym_mapping[dd->sym_count];
49
50 /* module is optional */
51 sym->module[0] = '\0';
52 /* trim the square brackets around the module name */
53 if (sscanf(buff, "%p %*c %s [%[^]]s", &address, sym->name, sym->module) < 2)
54 continue;
55 sym->address = (unsigned long)address;
56 if (!strcmp(sym->name, "__bpf_call_base")) {
57 dd->address_call_base = sym->address;
58 /* sysctl kernel.kptr_restrict was set */
59 if (!sym->address)
60 goto out;
61 }
62 if (sym->address)
63 dd->sym_count++;
64 }
65
66 fclose(fp);
67
68 qsort(dd->sym_mapping, dd->sym_count,
69 sizeof(*dd->sym_mapping), kernel_syms_cmp);
70 }
71
72 void kernel_syms_destroy(struct dump_data *dd)
73 {
74 free(dd->sym_mapping);
75 }
76
77 struct kernel_sym *kernel_syms_search(struct dump_data *dd,
78 unsigned long key)
79 {
80 struct kernel_sym sym = {
81 .address = key,
82 };
83
84 return dd->sym_mapping ?
85 bsearch(&sym, dd->sym_mapping, dd->sym_count,
86 sizeof(*dd->sym_mapping), kernel_syms_cmp) : NULL;
87 }
88
89 static void __printf(2, 3) print_insn(void *private_data, const char *fmt, ...)
90 {
91 va_list args;
92
93 va_start(args, fmt);
94 vprintf(fmt, args);
95 va_end(args);
96 }
97
98 static void __printf(2, 3)
99 print_insn_for_graph(void *private_data, const char *fmt, ...)
100 {
101 char buf[64], *p;
102 va_list args;
103
104 va_start(args, fmt);
105 vsnprintf(buf, sizeof(buf), fmt, args);
106 va_end(args);
107
108 p = buf;
109 while (*p != '\0') {
110 if (*p == '\n') {
111 memmove(p + 3, p, strlen(buf) + 1 - (p - buf));
112 /* Align each instruction dump row left. */
113 *p++ = '\\';
114 *p++ = 'l';
115 /* Output multiline concatenation. */
116 *p++ = '\\';
117 } else if (*p == '<' || *p == '>' || *p == '|' || *p == '&') {
118 memmove(p + 1, p, strlen(buf) + 1 - (p - buf));
119 /* Escape special character. */
120 *p++ = '\\';
121 }
122
123 p++;
124 }
125
126 printf("%s", buf);
127 }
128
129 static void __printf(2, 3)
130 print_insn_json(void *private_data, const char *fmt, ...)
131 {
132 unsigned int l = strlen(fmt);
133 char chomped_fmt[l];
134 va_list args;
135
136 va_start(args, fmt);
137 if (l > 0) {
138 strncpy(chomped_fmt, fmt, l - 1);
139 chomped_fmt[l - 1] = '\0';
140 }
141 jsonw_vprintf_enquote(json_wtr, chomped_fmt, args);
142 va_end(args);
143 }
144
145 static const char *print_call_pcrel(struct dump_data *dd,
146 struct kernel_sym *sym,
147 unsigned long address,
148 const struct bpf_insn *insn)
149 {
150 if (!dd->nr_jited_ksyms)
151 /* Do not show address for interpreted programs */
152 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
153 "%+d", insn->off);
154 else if (sym)
155 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
156 "%+d#%s", insn->off, sym->name);
157 else
158 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
159 "%+d#0x%lx", insn->off, address);
160 return dd->scratch_buff;
161 }
162
163 static const char *print_call_helper(struct dump_data *dd,
164 struct kernel_sym *sym,
165 unsigned long address)
166 {
167 if (sym)
168 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
169 "%s", sym->name);
170 else
171 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
172 "0x%lx", address);
173 return dd->scratch_buff;
174 }
175
176 static const char *print_call(void *private_data,
177 const struct bpf_insn *insn)
178 {
179 struct dump_data *dd = private_data;
180 unsigned long address = dd->address_call_base + insn->imm;
181 struct kernel_sym *sym;
182
183 if (insn->src_reg == BPF_PSEUDO_CALL &&
184 (__u32) insn->imm < dd->nr_jited_ksyms && dd->jited_ksyms)
185 address = dd->jited_ksyms[insn->imm];
186
187 sym = kernel_syms_search(dd, address);
188 if (insn->src_reg == BPF_PSEUDO_CALL)
189 return print_call_pcrel(dd, sym, address, insn);
190 else
191 return print_call_helper(dd, sym, address);
192 }
193
194 static const char *print_imm(void *private_data,
195 const struct bpf_insn *insn,
196 __u64 full_imm)
197 {
198 struct dump_data *dd = private_data;
199
200 if (insn->src_reg == BPF_PSEUDO_MAP_FD)
201 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
202 "map[id:%u]", insn->imm);
203 else if (insn->src_reg == BPF_PSEUDO_MAP_VALUE)
204 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
205 "map[id:%u][0]+%u", insn->imm, (insn + 1)->imm);
206 else if (insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE)
207 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
208 "map[idx:%u]+%u", insn->imm, (insn + 1)->imm);
209 else if (insn->src_reg == BPF_PSEUDO_FUNC)
210 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
211 "subprog[%+d]", insn->imm);
212 else
213 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
214 "0x%llx", (unsigned long long)full_imm);
215 return dd->scratch_buff;
216 }
217
218 void dump_xlated_json(struct dump_data *dd, void *buf, unsigned int len,
219 bool opcodes, bool linum)
220 {
221 const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo;
222 const struct bpf_insn_cbs cbs = {
223 .cb_print = print_insn_json,
224 .cb_call = print_call,
225 .cb_imm = print_imm,
226 .private_data = dd,
227 };
228 struct bpf_func_info *record;
229 struct bpf_insn *insn = buf;
230 struct btf *btf = dd->btf;
231 bool double_insn = false;
232 unsigned int nr_skip = 0;
233 char func_sig[1024];
234 unsigned int i;
235
236 jsonw_start_array(json_wtr);
237 record = dd->func_info;
238 for (i = 0; i < len / sizeof(*insn); i++) {
239 if (double_insn) {
240 double_insn = false;
241 continue;
242 }
243 double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);
244
245 jsonw_start_object(json_wtr);
246
247 if (btf && record) {
248 if (record->insn_off == i) {
249 btf_dumper_type_only(btf, record->type_id,
250 func_sig,
251 sizeof(func_sig));
252 if (func_sig[0] != '\0') {
253 jsonw_name(json_wtr, "proto");
254 jsonw_string(json_wtr, func_sig);
255 }
256 record = (void *)record + dd->finfo_rec_size;
257 }
258 }
259
260 if (prog_linfo) {
261 const struct bpf_line_info *linfo;
262
263 linfo = bpf_prog_linfo__lfind(prog_linfo, i, nr_skip);
264 if (linfo) {
265 btf_dump_linfo_json(btf, linfo, linum);
266 nr_skip++;
267 }
268 }
269
270 jsonw_name(json_wtr, "disasm");
271 print_bpf_insn(&cbs, insn + i, true);
272
273 if (opcodes) {
274 jsonw_name(json_wtr, "opcodes");
275 jsonw_start_object(json_wtr);
276
277 jsonw_name(json_wtr, "code");
278 jsonw_printf(json_wtr, "\"0x%02hhx\"", insn[i].code);
279
280 jsonw_name(json_wtr, "src_reg");
281 jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].src_reg);
282
283 jsonw_name(json_wtr, "dst_reg");
284 jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].dst_reg);
285
286 jsonw_name(json_wtr, "off");
287 print_hex_data_json((uint8_t *)(&insn[i].off), 2);
288
289 jsonw_name(json_wtr, "imm");
290 if (double_insn && i < len - 1)
291 print_hex_data_json((uint8_t *)(&insn[i].imm),
292 12);
293 else
294 print_hex_data_json((uint8_t *)(&insn[i].imm),
295 4);
296 jsonw_end_object(json_wtr);
297 }
298 jsonw_end_object(json_wtr);
299 }
300 jsonw_end_array(json_wtr);
301 }
302
303 void dump_xlated_plain(struct dump_data *dd, void *buf, unsigned int len,
304 bool opcodes, bool linum)
305 {
306 const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo;
307 const struct bpf_insn_cbs cbs = {
308 .cb_print = print_insn,
309 .cb_call = print_call,
310 .cb_imm = print_imm,
311 .private_data = dd,
312 };
313 struct bpf_func_info *record;
314 struct bpf_insn *insn = buf;
315 struct btf *btf = dd->btf;
316 unsigned int nr_skip = 0;
317 bool double_insn = false;
318 char func_sig[1024];
319 unsigned int i;
320
321 record = dd->func_info;
322 for (i = 0; i < len / sizeof(*insn); i++) {
323 if (double_insn) {
324 double_insn = false;
325 continue;
326 }
327
328 if (btf && record) {
329 if (record->insn_off == i) {
330 btf_dumper_type_only(btf, record->type_id,
331 func_sig,
332 sizeof(func_sig));
333 if (func_sig[0] != '\0')
334 printf("%s:\n", func_sig);
335 record = (void *)record + dd->finfo_rec_size;
336 }
337 }
338
339 if (prog_linfo) {
340 const struct bpf_line_info *linfo;
341
342 linfo = bpf_prog_linfo__lfind(prog_linfo, i, nr_skip);
343 if (linfo) {
344 btf_dump_linfo_plain(btf, linfo, "; ",
345 linum);
346 nr_skip++;
347 }
348 }
349
350 double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);
351
352 printf("% 4d: ", i);
353 print_bpf_insn(&cbs, insn + i, true);
354
355 if (opcodes) {
356 printf(" ");
357 fprint_hex(stdout, insn + i, 8, " ");
358 if (double_insn && i < len - 1) {
359 printf(" ");
360 fprint_hex(stdout, insn + i + 1, 8, " ");
361 }
362 printf("\n");
363 }
364 }
365 }
366
367 void dump_xlated_for_graph(struct dump_data *dd, void *buf_start, void *buf_end,
368 unsigned int start_idx,
369 bool opcodes, bool linum)
370 {
371 const struct bpf_insn_cbs cbs = {
372 .cb_print = print_insn_for_graph,
373 .cb_call = print_call,
374 .cb_imm = print_imm,
375 .private_data = dd,
376 };
377 const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo;
378 const struct bpf_line_info *last_linfo = NULL;
379 struct bpf_func_info *record = dd->func_info;
380 struct bpf_insn *insn_start = buf_start;
381 struct bpf_insn *insn_end = buf_end;
382 struct bpf_insn *cur = insn_start;
383 struct btf *btf = dd->btf;
384 bool double_insn = false;
385 char func_sig[1024];
386
387 for (; cur <= insn_end; cur++) {
388 unsigned int insn_off;
389
390 if (double_insn) {
391 double_insn = false;
392 continue;
393 }
394 double_insn = cur->code == (BPF_LD | BPF_IMM | BPF_DW);
395
396 insn_off = (unsigned int)(cur - insn_start + start_idx);
397 if (btf && record) {
398 if (record->insn_off == insn_off) {
399 btf_dumper_type_only(btf, record->type_id,
400 func_sig,
401 sizeof(func_sig));
402 if (func_sig[0] != '\0')
403 printf("; %s:\\l\\\n", func_sig);
404 record = (void *)record + dd->finfo_rec_size;
405 }
406 }
407
408 if (prog_linfo) {
409 const struct bpf_line_info *linfo;
410
411 linfo = bpf_prog_linfo__lfind(prog_linfo, insn_off, 0);
412 if (linfo && linfo != last_linfo) {
413 btf_dump_linfo_dotlabel(btf, linfo, linum);
414 last_linfo = linfo;
415 }
416 }
417
418 printf("%d: ", insn_off);
419 print_bpf_insn(&cbs, cur, true);
420
421 if (opcodes) {
422 printf("\\ \\ \\ \\ ");
423 fprint_hex(stdout, cur, 8, " ");
424 if (double_insn && cur <= insn_end - 1) {
425 printf(" ");
426 fprint_hex(stdout, cur + 1, 8, " ");
427 }
428 printf("\\l\\\n");
429 }
430
431 if (cur != insn_end)
432 printf("| ");
433 }
434 }
435
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