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