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 		if (sscanf(buff, "%p %*c %s", &address, sym->name) != 2)
50 			continue;
51 		sym->address = (unsigned long)address;
52 		if (!strcmp(sym->name, "__bpf_call_base")) {
53 			dd->address_call_base = sym->address;
54 			/* sysctl kernel.kptr_restrict was set */
55 			if (!sym->address)
56 				goto out;
57 		}
58 		if (sym->address)
59 			dd->sym_count++;
60 	}
61 
62 	fclose(fp);
63 
64 	qsort(dd->sym_mapping, dd->sym_count,
65 	      sizeof(*dd->sym_mapping), kernel_syms_cmp);
66 }
67 
68 void kernel_syms_destroy(struct dump_data *dd)
69 {
70 	free(dd->sym_mapping);
71 }
72 
73 struct kernel_sym *kernel_syms_search(struct dump_data *dd,
74 				      unsigned long key)
75 {
76 	struct kernel_sym sym = {
77 		.address = key,
78 	};
79 
80 	return dd->sym_mapping ?
81 	       bsearch(&sym, dd->sym_mapping, dd->sym_count,
82 		       sizeof(*dd->sym_mapping), kernel_syms_cmp) : NULL;
83 }
84 
85 static void __printf(2, 3) print_insn(void *private_data, const char *fmt, ...)
86 {
87 	va_list args;
88 
89 	va_start(args, fmt);
90 	vprintf(fmt, args);
91 	va_end(args);
92 }
93 
94 static void __printf(2, 3)
95 print_insn_for_graph(void *private_data, const char *fmt, ...)
96 {
97 	char buf[64], *p;
98 	va_list args;
99 
100 	va_start(args, fmt);
101 	vsnprintf(buf, sizeof(buf), fmt, args);
102 	va_end(args);
103 
104 	p = buf;
105 	while (*p != '\0') {
106 		if (*p == '\n') {
107 			memmove(p + 3, p, strlen(buf) + 1 - (p - buf));
108 			/* Align each instruction dump row left. */
109 			*p++ = '\\';
110 			*p++ = 'l';
111 			/* Output multiline concatenation. */
112 			*p++ = '\\';
113 		} else if (*p == '<' || *p == '>' || *p == '|' || *p == '&') {
114 			memmove(p + 1, p, strlen(buf) + 1 - (p - buf));
115 			/* Escape special character. */
116 			*p++ = '\\';
117 		}
118 
119 		p++;
120 	}
121 
122 	printf("%s", buf);
123 }
124 
125 static void __printf(2, 3)
126 print_insn_json(void *private_data, const char *fmt, ...)
127 {
128 	unsigned int l = strlen(fmt);
129 	char chomped_fmt[l];
130 	va_list args;
131 
132 	va_start(args, fmt);
133 	if (l > 0) {
134 		strncpy(chomped_fmt, fmt, l - 1);
135 		chomped_fmt[l - 1] = '\0';
136 	}
137 	jsonw_vprintf_enquote(json_wtr, chomped_fmt, args);
138 	va_end(args);
139 }
140 
141 static const char *print_call_pcrel(struct dump_data *dd,
142 				    struct kernel_sym *sym,
143 				    unsigned long address,
144 				    const struct bpf_insn *insn)
145 {
146 	if (!dd->nr_jited_ksyms)
147 		/* Do not show address for interpreted programs */
148 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
149 			"%+d", insn->off);
150 	else if (sym)
151 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
152 			 "%+d#%s", insn->off, sym->name);
153 	else
154 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
155 			 "%+d#0x%lx", insn->off, address);
156 	return dd->scratch_buff;
157 }
158 
159 static const char *print_call_helper(struct dump_data *dd,
160 				     struct kernel_sym *sym,
161 				     unsigned long address)
162 {
163 	if (sym)
164 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
165 			 "%s", sym->name);
166 	else
167 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
168 			 "0x%lx", address);
169 	return dd->scratch_buff;
170 }
171 
172 static const char *print_call(void *private_data,
173 			      const struct bpf_insn *insn)
174 {
175 	struct dump_data *dd = private_data;
176 	unsigned long address = dd->address_call_base + insn->imm;
177 	struct kernel_sym *sym;
178 
179 	if (insn->src_reg == BPF_PSEUDO_CALL &&
180 	    (__u32) insn->imm < dd->nr_jited_ksyms && dd->jited_ksyms)
181 		address = dd->jited_ksyms[insn->imm];
182 
183 	sym = kernel_syms_search(dd, address);
184 	if (insn->src_reg == BPF_PSEUDO_CALL)
185 		return print_call_pcrel(dd, sym, address, insn);
186 	else
187 		return print_call_helper(dd, sym, address);
188 }
189 
190 static const char *print_imm(void *private_data,
191 			     const struct bpf_insn *insn,
192 			     __u64 full_imm)
193 {
194 	struct dump_data *dd = private_data;
195 
196 	if (insn->src_reg == BPF_PSEUDO_MAP_FD)
197 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
198 			 "map[id:%u]", insn->imm);
199 	else if (insn->src_reg == BPF_PSEUDO_MAP_VALUE)
200 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
201 			 "map[id:%u][0]+%u", insn->imm, (insn + 1)->imm);
202 	else if (insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE)
203 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
204 			 "map[idx:%u]+%u", insn->imm, (insn + 1)->imm);
205 	else if (insn->src_reg == BPF_PSEUDO_FUNC)
206 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
207 			 "subprog[%+d]", insn->imm);
208 	else
209 		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
210 			 "0x%llx", (unsigned long long)full_imm);
211 	return dd->scratch_buff;
212 }
213 
214 void dump_xlated_json(struct dump_data *dd, void *buf, unsigned int len,
215 		      bool opcodes, bool linum)
216 {
217 	const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo;
218 	const struct bpf_insn_cbs cbs = {
219 		.cb_print	= print_insn_json,
220 		.cb_call	= print_call,
221 		.cb_imm		= print_imm,
222 		.private_data	= dd,
223 	};
224 	struct bpf_func_info *record;
225 	struct bpf_insn *insn = buf;
226 	struct btf *btf = dd->btf;
227 	bool double_insn = false;
228 	unsigned int nr_skip = 0;
229 	char func_sig[1024];
230 	unsigned int i;
231 
232 	jsonw_start_array(json_wtr);
233 	record = dd->func_info;
234 	for (i = 0; i < len / sizeof(*insn); i++) {
235 		if (double_insn) {
236 			double_insn = false;
237 			continue;
238 		}
239 		double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);
240 
241 		jsonw_start_object(json_wtr);
242 
243 		if (btf && record) {
244 			if (record->insn_off == i) {
245 				btf_dumper_type_only(btf, record->type_id,
246 						     func_sig,
247 						     sizeof(func_sig));
248 				if (func_sig[0] != '\0') {
249 					jsonw_name(json_wtr, "proto");
250 					jsonw_string(json_wtr, func_sig);
251 				}
252 				record = (void *)record + dd->finfo_rec_size;
253 			}
254 		}
255 
256 		if (prog_linfo) {
257 			const struct bpf_line_info *linfo;
258 
259 			linfo = bpf_prog_linfo__lfind(prog_linfo, i, nr_skip);
260 			if (linfo) {
261 				btf_dump_linfo_json(btf, linfo, linum);
262 				nr_skip++;
263 			}
264 		}
265 
266 		jsonw_name(json_wtr, "disasm");
267 		print_bpf_insn(&cbs, insn + i, true);
268 
269 		if (opcodes) {
270 			jsonw_name(json_wtr, "opcodes");
271 			jsonw_start_object(json_wtr);
272 
273 			jsonw_name(json_wtr, "code");
274 			jsonw_printf(json_wtr, "\"0x%02hhx\"", insn[i].code);
275 
276 			jsonw_name(json_wtr, "src_reg");
277 			jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].src_reg);
278 
279 			jsonw_name(json_wtr, "dst_reg");
280 			jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].dst_reg);
281 
282 			jsonw_name(json_wtr, "off");
283 			print_hex_data_json((uint8_t *)(&insn[i].off), 2);
284 
285 			jsonw_name(json_wtr, "imm");
286 			if (double_insn && i < len - 1)
287 				print_hex_data_json((uint8_t *)(&insn[i].imm),
288 						    12);
289 			else
290 				print_hex_data_json((uint8_t *)(&insn[i].imm),
291 						    4);
292 			jsonw_end_object(json_wtr);
293 		}
294 		jsonw_end_object(json_wtr);
295 	}
296 	jsonw_end_array(json_wtr);
297 }
298 
299 void dump_xlated_plain(struct dump_data *dd, void *buf, unsigned int len,
300 		       bool opcodes, bool linum)
301 {
302 	const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo;
303 	const struct bpf_insn_cbs cbs = {
304 		.cb_print	= print_insn,
305 		.cb_call	= print_call,
306 		.cb_imm		= print_imm,
307 		.private_data	= dd,
308 	};
309 	struct bpf_func_info *record;
310 	struct bpf_insn *insn = buf;
311 	struct btf *btf = dd->btf;
312 	unsigned int nr_skip = 0;
313 	bool double_insn = false;
314 	char func_sig[1024];
315 	unsigned int i;
316 
317 	record = dd->func_info;
318 	for (i = 0; i < len / sizeof(*insn); i++) {
319 		if (double_insn) {
320 			double_insn = false;
321 			continue;
322 		}
323 
324 		if (btf && record) {
325 			if (record->insn_off == i) {
326 				btf_dumper_type_only(btf, record->type_id,
327 						     func_sig,
328 						     sizeof(func_sig));
329 				if (func_sig[0] != '\0')
330 					printf("%s:\n", func_sig);
331 				record = (void *)record + dd->finfo_rec_size;
332 			}
333 		}
334 
335 		if (prog_linfo) {
336 			const struct bpf_line_info *linfo;
337 
338 			linfo = bpf_prog_linfo__lfind(prog_linfo, i, nr_skip);
339 			if (linfo) {
340 				btf_dump_linfo_plain(btf, linfo, "; ",
341 						     linum);
342 				nr_skip++;
343 			}
344 		}
345 
346 		double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);
347 
348 		printf("% 4d: ", i);
349 		print_bpf_insn(&cbs, insn + i, true);
350 
351 		if (opcodes) {
352 			printf("       ");
353 			fprint_hex(stdout, insn + i, 8, " ");
354 			if (double_insn && i < len - 1) {
355 				printf(" ");
356 				fprint_hex(stdout, insn + i + 1, 8, " ");
357 			}
358 			printf("\n");
359 		}
360 	}
361 }
362 
363 void dump_xlated_for_graph(struct dump_data *dd, void *buf_start, void *buf_end,
364 			   unsigned int start_idx)
365 {
366 	const struct bpf_insn_cbs cbs = {
367 		.cb_print	= print_insn_for_graph,
368 		.cb_call	= print_call,
369 		.cb_imm		= print_imm,
370 		.private_data	= dd,
371 	};
372 	struct bpf_insn *insn_start = buf_start;
373 	struct bpf_insn *insn_end = buf_end;
374 	struct bpf_insn *cur = insn_start;
375 
376 	for (; cur <= insn_end; cur++) {
377 		printf("% 4d: ", (int)(cur - insn_start + start_idx));
378 		print_bpf_insn(&cbs, cur, true);
379 		if (cur != insn_end)
380 			printf(" | ");
381 	}
382 }
383