1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Common code for probe-based Dynamic events.
4  *
5  * This code was copied from kernel/trace/trace_kprobe.c written by
6  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
7  *
8  * Updates to make this generic:
9  * Copyright (C) IBM Corporation, 2010-2011
10  * Author:     Srikar Dronamraju
11  */
12 #define pr_fmt(fmt)	"trace_probe: " fmt
13 
14 #include "trace_probe.h"
15 
16 #undef C
17 #define C(a, b)		b
18 
19 static const char *trace_probe_err_text[] = { ERRORS };
20 
21 static const char *reserved_field_names[] = {
22 	"common_type",
23 	"common_flags",
24 	"common_preempt_count",
25 	"common_pid",
26 	"common_tgid",
27 	FIELD_STRING_IP,
28 	FIELD_STRING_RETIP,
29 	FIELD_STRING_FUNC,
30 };
31 
32 /* Printing  in basic type function template */
33 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)			\
34 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
35 {									\
36 	trace_seq_printf(s, fmt, *(type *)data);			\
37 	return !trace_seq_has_overflowed(s);				\
38 }									\
39 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
40 
41 DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
42 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
43 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
44 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
45 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
46 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
47 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
48 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
49 DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
50 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
51 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
52 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
53 
PRINT_TYPE_FUNC_NAME(symbol)54 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
55 {
56 	trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
57 	return !trace_seq_has_overflowed(s);
58 }
59 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
60 
61 /* Print type function for string type */
PRINT_TYPE_FUNC_NAME(string)62 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
63 {
64 	int len = *(u32 *)data >> 16;
65 
66 	if (!len)
67 		trace_seq_puts(s, "(fault)");
68 	else
69 		trace_seq_printf(s, "\"%s\"",
70 				 (const char *)get_loc_data(data, ent));
71 	return !trace_seq_has_overflowed(s);
72 }
73 
74 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
75 
76 /* Fetch type information table */
77 static const struct fetch_type probe_fetch_types[] = {
78 	/* Special types */
79 	__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
80 			    "__data_loc char[]"),
81 	__ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1,
82 			    "__data_loc char[]"),
83 	/* Basic types */
84 	ASSIGN_FETCH_TYPE(u8,  u8,  0),
85 	ASSIGN_FETCH_TYPE(u16, u16, 0),
86 	ASSIGN_FETCH_TYPE(u32, u32, 0),
87 	ASSIGN_FETCH_TYPE(u64, u64, 0),
88 	ASSIGN_FETCH_TYPE(s8,  u8,  1),
89 	ASSIGN_FETCH_TYPE(s16, u16, 1),
90 	ASSIGN_FETCH_TYPE(s32, u32, 1),
91 	ASSIGN_FETCH_TYPE(s64, u64, 1),
92 	ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
93 	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
94 	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
95 	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
96 	ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
97 
98 	ASSIGN_FETCH_TYPE_END
99 };
100 
find_fetch_type(const char * type)101 static const struct fetch_type *find_fetch_type(const char *type)
102 {
103 	int i;
104 
105 	if (!type)
106 		type = DEFAULT_FETCH_TYPE_STR;
107 
108 	/* Special case: bitfield */
109 	if (*type == 'b') {
110 		unsigned long bs;
111 
112 		type = strchr(type, '/');
113 		if (!type)
114 			goto fail;
115 
116 		type++;
117 		if (kstrtoul(type, 0, &bs))
118 			goto fail;
119 
120 		switch (bs) {
121 		case 8:
122 			return find_fetch_type("u8");
123 		case 16:
124 			return find_fetch_type("u16");
125 		case 32:
126 			return find_fetch_type("u32");
127 		case 64:
128 			return find_fetch_type("u64");
129 		default:
130 			goto fail;
131 		}
132 	}
133 
134 	for (i = 0; probe_fetch_types[i].name; i++) {
135 		if (strcmp(type, probe_fetch_types[i].name) == 0)
136 			return &probe_fetch_types[i];
137 	}
138 
139 fail:
140 	return NULL;
141 }
142 
143 static struct trace_probe_log trace_probe_log;
144 
trace_probe_log_init(const char * subsystem,int argc,const char ** argv)145 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
146 {
147 	trace_probe_log.subsystem = subsystem;
148 	trace_probe_log.argc = argc;
149 	trace_probe_log.argv = argv;
150 	trace_probe_log.index = 0;
151 }
152 
trace_probe_log_clear(void)153 void trace_probe_log_clear(void)
154 {
155 	memset(&trace_probe_log, 0, sizeof(trace_probe_log));
156 }
157 
trace_probe_log_set_index(int index)158 void trace_probe_log_set_index(int index)
159 {
160 	trace_probe_log.index = index;
161 }
162 
__trace_probe_log_err(int offset,int err_type)163 void __trace_probe_log_err(int offset, int err_type)
164 {
165 	char *command, *p;
166 	int i, len = 0, pos = 0;
167 
168 	if (!trace_probe_log.argv)
169 		return;
170 
171 	/* Recalculate the length and allocate buffer */
172 	for (i = 0; i < trace_probe_log.argc; i++) {
173 		if (i == trace_probe_log.index)
174 			pos = len;
175 		len += strlen(trace_probe_log.argv[i]) + 1;
176 	}
177 	command = kzalloc(len, GFP_KERNEL);
178 	if (!command)
179 		return;
180 
181 	if (trace_probe_log.index >= trace_probe_log.argc) {
182 		/**
183 		 * Set the error position is next to the last arg + space.
184 		 * Note that len includes the terminal null and the cursor
185 		 * appears at pos + 1.
186 		 */
187 		pos = len;
188 		offset = 0;
189 	}
190 
191 	/* And make a command string from argv array */
192 	p = command;
193 	for (i = 0; i < trace_probe_log.argc; i++) {
194 		len = strlen(trace_probe_log.argv[i]);
195 		strcpy(p, trace_probe_log.argv[i]);
196 		p[len] = ' ';
197 		p += len + 1;
198 	}
199 	*(p - 1) = '\0';
200 
201 	tracing_log_err(NULL, trace_probe_log.subsystem, command,
202 			trace_probe_err_text, err_type, pos + offset);
203 
204 	kfree(command);
205 }
206 
207 /* Split symbol and offset. */
traceprobe_split_symbol_offset(char * symbol,long * offset)208 int traceprobe_split_symbol_offset(char *symbol, long *offset)
209 {
210 	char *tmp;
211 	int ret;
212 
213 	if (!offset)
214 		return -EINVAL;
215 
216 	tmp = strpbrk(symbol, "+-");
217 	if (tmp) {
218 		ret = kstrtol(tmp, 0, offset);
219 		if (ret)
220 			return ret;
221 		*tmp = '\0';
222 	} else
223 		*offset = 0;
224 
225 	return 0;
226 }
227 
228 /* @buf must has MAX_EVENT_NAME_LEN size */
traceprobe_parse_event_name(const char ** pevent,const char ** pgroup,char * buf,int offset)229 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
230 				char *buf, int offset)
231 {
232 	const char *slash, *event = *pevent;
233 	int len;
234 
235 	slash = strchr(event, '/');
236 	if (!slash)
237 		slash = strchr(event, '.');
238 
239 	if (slash) {
240 		if (slash == event) {
241 			trace_probe_log_err(offset, NO_GROUP_NAME);
242 			return -EINVAL;
243 		}
244 		if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
245 			trace_probe_log_err(offset, GROUP_TOO_LONG);
246 			return -EINVAL;
247 		}
248 		strlcpy(buf, event, slash - event + 1);
249 		if (!is_good_system_name(buf)) {
250 			trace_probe_log_err(offset, BAD_GROUP_NAME);
251 			return -EINVAL;
252 		}
253 		*pgroup = buf;
254 		*pevent = slash + 1;
255 		offset += slash - event + 1;
256 		event = *pevent;
257 	}
258 	len = strlen(event);
259 	if (len == 0) {
260 		if (slash) {
261 			*pevent = NULL;
262 			return 0;
263 		}
264 		trace_probe_log_err(offset, NO_EVENT_NAME);
265 		return -EINVAL;
266 	} else if (len > MAX_EVENT_NAME_LEN) {
267 		trace_probe_log_err(offset, EVENT_TOO_LONG);
268 		return -EINVAL;
269 	}
270 	if (!is_good_name(event)) {
271 		trace_probe_log_err(offset, BAD_EVENT_NAME);
272 		return -EINVAL;
273 	}
274 	return 0;
275 }
276 
277 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
278 
parse_probe_vars(char * arg,const struct fetch_type * t,struct fetch_insn * code,unsigned int flags,int offs)279 static int parse_probe_vars(char *arg, const struct fetch_type *t,
280 			struct fetch_insn *code, unsigned int flags, int offs)
281 {
282 	unsigned long param;
283 	int ret = 0;
284 	int len;
285 
286 	if (flags & TPARG_FL_TPOINT) {
287 		if (code->data)
288 			return -EFAULT;
289 		code->data = kstrdup(arg, GFP_KERNEL);
290 		if (!code->data)
291 			return -ENOMEM;
292 		code->op = FETCH_OP_TP_ARG;
293 	} else if (strcmp(arg, "retval") == 0) {
294 		if (flags & TPARG_FL_RETURN) {
295 			code->op = FETCH_OP_RETVAL;
296 		} else {
297 			trace_probe_log_err(offs, RETVAL_ON_PROBE);
298 			ret = -EINVAL;
299 		}
300 	} else if ((len = str_has_prefix(arg, "stack"))) {
301 		if (arg[len] == '\0') {
302 			code->op = FETCH_OP_STACKP;
303 		} else if (isdigit(arg[len])) {
304 			ret = kstrtoul(arg + len, 10, &param);
305 			if (ret) {
306 				goto inval_var;
307 			} else if ((flags & TPARG_FL_KERNEL) &&
308 				    param > PARAM_MAX_STACK) {
309 				trace_probe_log_err(offs, BAD_STACK_NUM);
310 				ret = -EINVAL;
311 			} else {
312 				code->op = FETCH_OP_STACK;
313 				code->param = (unsigned int)param;
314 			}
315 		} else
316 			goto inval_var;
317 	} else if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
318 		code->op = FETCH_OP_COMM;
319 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
320 	} else if (((flags & TPARG_FL_MASK) ==
321 		    (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
322 		   (len = str_has_prefix(arg, "arg"))) {
323 		ret = kstrtoul(arg + len, 10, &param);
324 		if (ret) {
325 			goto inval_var;
326 		} else if (!param || param > PARAM_MAX_STACK) {
327 			trace_probe_log_err(offs, BAD_ARG_NUM);
328 			return -EINVAL;
329 		}
330 		code->op = FETCH_OP_ARG;
331 		code->param = (unsigned int)param - 1;
332 #endif
333 	} else
334 		goto inval_var;
335 
336 	return ret;
337 
338 inval_var:
339 	trace_probe_log_err(offs, BAD_VAR);
340 	return -EINVAL;
341 }
342 
str_to_immediate(char * str,unsigned long * imm)343 static int str_to_immediate(char *str, unsigned long *imm)
344 {
345 	if (isdigit(str[0]))
346 		return kstrtoul(str, 0, imm);
347 	else if (str[0] == '-')
348 		return kstrtol(str, 0, (long *)imm);
349 	else if (str[0] == '+')
350 		return kstrtol(str + 1, 0, (long *)imm);
351 	return -EINVAL;
352 }
353 
__parse_imm_string(char * str,char ** pbuf,int offs)354 static int __parse_imm_string(char *str, char **pbuf, int offs)
355 {
356 	size_t len = strlen(str);
357 
358 	if (str[len - 1] != '"') {
359 		trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
360 		return -EINVAL;
361 	}
362 	*pbuf = kstrndup(str, len - 1, GFP_KERNEL);
363 	if (!*pbuf)
364 		return -ENOMEM;
365 	return 0;
366 }
367 
368 /* Recursive argument parser */
369 static int
parse_probe_arg(char * arg,const struct fetch_type * type,struct fetch_insn ** pcode,struct fetch_insn * end,unsigned int flags,int offs)370 parse_probe_arg(char *arg, const struct fetch_type *type,
371 		struct fetch_insn **pcode, struct fetch_insn *end,
372 		unsigned int flags, int offs)
373 {
374 	struct fetch_insn *code = *pcode;
375 	unsigned long param;
376 	int deref = FETCH_OP_DEREF;
377 	long offset = 0;
378 	char *tmp;
379 	int ret = 0;
380 
381 	switch (arg[0]) {
382 	case '$':
383 		ret = parse_probe_vars(arg + 1, type, code, flags, offs);
384 		break;
385 
386 	case '%':	/* named register */
387 		if (flags & TPARG_FL_TPOINT) {
388 			/* eprobes do not handle registers */
389 			trace_probe_log_err(offs, BAD_VAR);
390 			break;
391 		}
392 		ret = regs_query_register_offset(arg + 1);
393 		if (ret >= 0) {
394 			code->op = FETCH_OP_REG;
395 			code->param = (unsigned int)ret;
396 			ret = 0;
397 		} else
398 			trace_probe_log_err(offs, BAD_REG_NAME);
399 		break;
400 
401 	case '@':	/* memory, file-offset or symbol */
402 		if (isdigit(arg[1])) {
403 			ret = kstrtoul(arg + 1, 0, &param);
404 			if (ret) {
405 				trace_probe_log_err(offs, BAD_MEM_ADDR);
406 				break;
407 			}
408 			/* load address */
409 			code->op = FETCH_OP_IMM;
410 			code->immediate = param;
411 		} else if (arg[1] == '+') {
412 			/* kprobes don't support file offsets */
413 			if (flags & TPARG_FL_KERNEL) {
414 				trace_probe_log_err(offs, FILE_ON_KPROBE);
415 				return -EINVAL;
416 			}
417 			ret = kstrtol(arg + 2, 0, &offset);
418 			if (ret) {
419 				trace_probe_log_err(offs, BAD_FILE_OFFS);
420 				break;
421 			}
422 
423 			code->op = FETCH_OP_FOFFS;
424 			code->immediate = (unsigned long)offset;  // imm64?
425 		} else {
426 			/* uprobes don't support symbols */
427 			if (!(flags & TPARG_FL_KERNEL)) {
428 				trace_probe_log_err(offs, SYM_ON_UPROBE);
429 				return -EINVAL;
430 			}
431 			/* Preserve symbol for updating */
432 			code->op = FETCH_NOP_SYMBOL;
433 			code->data = kstrdup(arg + 1, GFP_KERNEL);
434 			if (!code->data)
435 				return -ENOMEM;
436 			if (++code == end) {
437 				trace_probe_log_err(offs, TOO_MANY_OPS);
438 				return -EINVAL;
439 			}
440 			code->op = FETCH_OP_IMM;
441 			code->immediate = 0;
442 		}
443 		/* These are fetching from memory */
444 		if (++code == end) {
445 			trace_probe_log_err(offs, TOO_MANY_OPS);
446 			return -EINVAL;
447 		}
448 		*pcode = code;
449 		code->op = FETCH_OP_DEREF;
450 		code->offset = offset;
451 		break;
452 
453 	case '+':	/* deref memory */
454 	case '-':
455 		if (arg[1] == 'u') {
456 			deref = FETCH_OP_UDEREF;
457 			arg[1] = arg[0];
458 			arg++;
459 		}
460 		if (arg[0] == '+')
461 			arg++;	/* Skip '+', because kstrtol() rejects it. */
462 		tmp = strchr(arg, '(');
463 		if (!tmp) {
464 			trace_probe_log_err(offs, DEREF_NEED_BRACE);
465 			return -EINVAL;
466 		}
467 		*tmp = '\0';
468 		ret = kstrtol(arg, 0, &offset);
469 		if (ret) {
470 			trace_probe_log_err(offs, BAD_DEREF_OFFS);
471 			break;
472 		}
473 		offs += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
474 		arg = tmp + 1;
475 		tmp = strrchr(arg, ')');
476 		if (!tmp) {
477 			trace_probe_log_err(offs + strlen(arg),
478 					    DEREF_OPEN_BRACE);
479 			return -EINVAL;
480 		} else {
481 			const struct fetch_type *t2 = find_fetch_type(NULL);
482 
483 			*tmp = '\0';
484 			ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
485 			if (ret)
486 				break;
487 			if (code->op == FETCH_OP_COMM ||
488 			    code->op == FETCH_OP_DATA) {
489 				trace_probe_log_err(offs, COMM_CANT_DEREF);
490 				return -EINVAL;
491 			}
492 			if (++code == end) {
493 				trace_probe_log_err(offs, TOO_MANY_OPS);
494 				return -EINVAL;
495 			}
496 			*pcode = code;
497 
498 			code->op = deref;
499 			code->offset = offset;
500 		}
501 		break;
502 	case '\\':	/* Immediate value */
503 		if (arg[1] == '"') {	/* Immediate string */
504 			ret = __parse_imm_string(arg + 2, &tmp, offs + 2);
505 			if (ret)
506 				break;
507 			code->op = FETCH_OP_DATA;
508 			code->data = tmp;
509 		} else {
510 			ret = str_to_immediate(arg + 1, &code->immediate);
511 			if (ret)
512 				trace_probe_log_err(offs + 1, BAD_IMM);
513 			else
514 				code->op = FETCH_OP_IMM;
515 		}
516 		break;
517 	}
518 	if (!ret && code->op == FETCH_OP_NOP) {
519 		/* Parsed, but do not find fetch method */
520 		trace_probe_log_err(offs, BAD_FETCH_ARG);
521 		ret = -EINVAL;
522 	}
523 	return ret;
524 }
525 
526 #define BYTES_TO_BITS(nb)	((BITS_PER_LONG * (nb)) / sizeof(long))
527 
528 /* Bitfield type needs to be parsed into a fetch function */
__parse_bitfield_probe_arg(const char * bf,const struct fetch_type * t,struct fetch_insn ** pcode)529 static int __parse_bitfield_probe_arg(const char *bf,
530 				      const struct fetch_type *t,
531 				      struct fetch_insn **pcode)
532 {
533 	struct fetch_insn *code = *pcode;
534 	unsigned long bw, bo;
535 	char *tail;
536 
537 	if (*bf != 'b')
538 		return 0;
539 
540 	bw = simple_strtoul(bf + 1, &tail, 0);	/* Use simple one */
541 
542 	if (bw == 0 || *tail != '@')
543 		return -EINVAL;
544 
545 	bf = tail + 1;
546 	bo = simple_strtoul(bf, &tail, 0);
547 
548 	if (tail == bf || *tail != '/')
549 		return -EINVAL;
550 	code++;
551 	if (code->op != FETCH_OP_NOP)
552 		return -EINVAL;
553 	*pcode = code;
554 
555 	code->op = FETCH_OP_MOD_BF;
556 	code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
557 	code->rshift = BYTES_TO_BITS(t->size) - bw;
558 	code->basesize = t->size;
559 
560 	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
561 }
562 
563 /* String length checking wrapper */
traceprobe_parse_probe_arg_body(const char * argv,ssize_t * size,struct probe_arg * parg,unsigned int flags,int offset)564 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
565 		struct probe_arg *parg, unsigned int flags, int offset)
566 {
567 	struct fetch_insn *code, *scode, *tmp = NULL;
568 	char *t, *t2, *t3;
569 	char *arg;
570 	int ret, len;
571 
572 	arg = kstrdup(argv, GFP_KERNEL);
573 	if (!arg)
574 		return -ENOMEM;
575 
576 	ret = -EINVAL;
577 	len = strlen(arg);
578 	if (len > MAX_ARGSTR_LEN) {
579 		trace_probe_log_err(offset, ARG_TOO_LONG);
580 		goto out;
581 	} else if (len == 0) {
582 		trace_probe_log_err(offset, NO_ARG_BODY);
583 		goto out;
584 	}
585 
586 	ret = -ENOMEM;
587 	parg->comm = kstrdup(arg, GFP_KERNEL);
588 	if (!parg->comm)
589 		goto out;
590 
591 	ret = -EINVAL;
592 	t = strchr(arg, ':');
593 	if (t) {
594 		*t = '\0';
595 		t2 = strchr(++t, '[');
596 		if (t2) {
597 			*t2++ = '\0';
598 			t3 = strchr(t2, ']');
599 			if (!t3) {
600 				offset += t2 + strlen(t2) - arg;
601 				trace_probe_log_err(offset,
602 						    ARRAY_NO_CLOSE);
603 				goto out;
604 			} else if (t3[1] != '\0') {
605 				trace_probe_log_err(offset + t3 + 1 - arg,
606 						    BAD_ARRAY_SUFFIX);
607 				goto out;
608 			}
609 			*t3 = '\0';
610 			if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
611 				trace_probe_log_err(offset + t2 - arg,
612 						    BAD_ARRAY_NUM);
613 				goto out;
614 			}
615 			if (parg->count > MAX_ARRAY_LEN) {
616 				trace_probe_log_err(offset + t2 - arg,
617 						    ARRAY_TOO_BIG);
618 				goto out;
619 			}
620 		}
621 	}
622 
623 	/*
624 	 * Since $comm and immediate string can not be dereferenced,
625 	 * we can find those by strcmp. But ignore for eprobes.
626 	 */
627 	if (!(flags & TPARG_FL_TPOINT) &&
628 	    (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
629 	     strncmp(arg, "\\\"", 2) == 0)) {
630 		/* The type of $comm must be "string", and not an array. */
631 		if (parg->count || (t && strcmp(t, "string")))
632 			goto out;
633 		parg->type = find_fetch_type("string");
634 	} else
635 		parg->type = find_fetch_type(t);
636 	if (!parg->type) {
637 		trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
638 		goto out;
639 	}
640 	parg->offset = *size;
641 	*size += parg->type->size * (parg->count ?: 1);
642 
643 	ret = -ENOMEM;
644 	if (parg->count) {
645 		len = strlen(parg->type->fmttype) + 6;
646 		parg->fmt = kmalloc(len, GFP_KERNEL);
647 		if (!parg->fmt)
648 			goto out;
649 		snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
650 			 parg->count);
651 	}
652 
653 	code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
654 	if (!code)
655 		goto out;
656 	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
657 
658 	ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
659 			      flags, offset);
660 	if (ret)
661 		goto fail;
662 
663 	ret = -EINVAL;
664 	/* Store operation */
665 	if (!strcmp(parg->type->name, "string") ||
666 	    !strcmp(parg->type->name, "ustring")) {
667 		if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
668 		    code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
669 		    code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
670 			trace_probe_log_err(offset + (t ? (t - arg) : 0),
671 					    BAD_STRING);
672 			goto fail;
673 		}
674 		if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
675 		     code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
676 		     parg->count) {
677 			/*
678 			 * IMM, DATA and COMM is pointing actual address, those
679 			 * must be kept, and if parg->count != 0, this is an
680 			 * array of string pointers instead of string address
681 			 * itself.
682 			 */
683 			code++;
684 			if (code->op != FETCH_OP_NOP) {
685 				trace_probe_log_err(offset, TOO_MANY_OPS);
686 				goto fail;
687 			}
688 		}
689 		/* If op == DEREF, replace it with STRING */
690 		if (!strcmp(parg->type->name, "ustring") ||
691 		    code->op == FETCH_OP_UDEREF)
692 			code->op = FETCH_OP_ST_USTRING;
693 		else
694 			code->op = FETCH_OP_ST_STRING;
695 		code->size = parg->type->size;
696 		parg->dynamic = true;
697 	} else if (code->op == FETCH_OP_DEREF) {
698 		code->op = FETCH_OP_ST_MEM;
699 		code->size = parg->type->size;
700 	} else if (code->op == FETCH_OP_UDEREF) {
701 		code->op = FETCH_OP_ST_UMEM;
702 		code->size = parg->type->size;
703 	} else {
704 		code++;
705 		if (code->op != FETCH_OP_NOP) {
706 			trace_probe_log_err(offset, TOO_MANY_OPS);
707 			goto fail;
708 		}
709 		code->op = FETCH_OP_ST_RAW;
710 		code->size = parg->type->size;
711 	}
712 	scode = code;
713 	/* Modify operation */
714 	if (t != NULL) {
715 		ret = __parse_bitfield_probe_arg(t, parg->type, &code);
716 		if (ret) {
717 			trace_probe_log_err(offset + t - arg, BAD_BITFIELD);
718 			goto fail;
719 		}
720 	}
721 	ret = -EINVAL;
722 	/* Loop(Array) operation */
723 	if (parg->count) {
724 		if (scode->op != FETCH_OP_ST_MEM &&
725 		    scode->op != FETCH_OP_ST_STRING &&
726 		    scode->op != FETCH_OP_ST_USTRING) {
727 			trace_probe_log_err(offset + (t ? (t - arg) : 0),
728 					    BAD_STRING);
729 			goto fail;
730 		}
731 		code++;
732 		if (code->op != FETCH_OP_NOP) {
733 			trace_probe_log_err(offset, TOO_MANY_OPS);
734 			goto fail;
735 		}
736 		code->op = FETCH_OP_LP_ARRAY;
737 		code->param = parg->count;
738 	}
739 	code++;
740 	code->op = FETCH_OP_END;
741 
742 	ret = 0;
743 	/* Shrink down the code buffer */
744 	parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
745 	if (!parg->code)
746 		ret = -ENOMEM;
747 	else
748 		memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
749 
750 fail:
751 	if (ret) {
752 		for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
753 			if (code->op == FETCH_NOP_SYMBOL ||
754 			    code->op == FETCH_OP_DATA)
755 				kfree(code->data);
756 	}
757 	kfree(tmp);
758 out:
759 	kfree(arg);
760 
761 	return ret;
762 }
763 
764 /* Return 1 if name is reserved or already used by another argument */
traceprobe_conflict_field_name(const char * name,struct probe_arg * args,int narg)765 static int traceprobe_conflict_field_name(const char *name,
766 					  struct probe_arg *args, int narg)
767 {
768 	int i;
769 
770 	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
771 		if (strcmp(reserved_field_names[i], name) == 0)
772 			return 1;
773 
774 	for (i = 0; i < narg; i++)
775 		if (strcmp(args[i].name, name) == 0)
776 			return 1;
777 
778 	return 0;
779 }
780 
traceprobe_parse_probe_arg(struct trace_probe * tp,int i,const char * arg,unsigned int flags)781 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
782 				unsigned int flags)
783 {
784 	struct probe_arg *parg = &tp->args[i];
785 	const char *body;
786 
787 	/* Increment count for freeing args in error case */
788 	tp->nr_args++;
789 
790 	body = strchr(arg, '=');
791 	if (body) {
792 		if (body - arg > MAX_ARG_NAME_LEN) {
793 			trace_probe_log_err(0, ARG_NAME_TOO_LONG);
794 			return -EINVAL;
795 		} else if (body == arg) {
796 			trace_probe_log_err(0, NO_ARG_NAME);
797 			return -EINVAL;
798 		}
799 		parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
800 		body++;
801 	} else {
802 		/* If argument name is omitted, set "argN" */
803 		parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
804 		body = arg;
805 	}
806 	if (!parg->name)
807 		return -ENOMEM;
808 
809 	if (!is_good_name(parg->name)) {
810 		trace_probe_log_err(0, BAD_ARG_NAME);
811 		return -EINVAL;
812 	}
813 	if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
814 		trace_probe_log_err(0, USED_ARG_NAME);
815 		return -EINVAL;
816 	}
817 	/* Parse fetch argument */
818 	return traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags,
819 					       body - arg);
820 }
821 
traceprobe_free_probe_arg(struct probe_arg * arg)822 void traceprobe_free_probe_arg(struct probe_arg *arg)
823 {
824 	struct fetch_insn *code = arg->code;
825 
826 	while (code && code->op != FETCH_OP_END) {
827 		if (code->op == FETCH_NOP_SYMBOL ||
828 		    code->op == FETCH_OP_DATA)
829 			kfree(code->data);
830 		code++;
831 	}
832 	kfree(arg->code);
833 	kfree(arg->name);
834 	kfree(arg->comm);
835 	kfree(arg->fmt);
836 }
837 
traceprobe_update_arg(struct probe_arg * arg)838 int traceprobe_update_arg(struct probe_arg *arg)
839 {
840 	struct fetch_insn *code = arg->code;
841 	long offset;
842 	char *tmp;
843 	char c;
844 	int ret = 0;
845 
846 	while (code && code->op != FETCH_OP_END) {
847 		if (code->op == FETCH_NOP_SYMBOL) {
848 			if (code[1].op != FETCH_OP_IMM)
849 				return -EINVAL;
850 
851 			tmp = strpbrk(code->data, "+-");
852 			if (tmp)
853 				c = *tmp;
854 			ret = traceprobe_split_symbol_offset(code->data,
855 							     &offset);
856 			if (ret)
857 				return ret;
858 
859 			code[1].immediate =
860 				(unsigned long)kallsyms_lookup_name(code->data);
861 			if (tmp)
862 				*tmp = c;
863 			if (!code[1].immediate)
864 				return -ENOENT;
865 			code[1].immediate += offset;
866 		}
867 		code++;
868 	}
869 	return 0;
870 }
871 
872 /* When len=0, we just calculate the needed length */
873 #define LEN_OR_ZERO (len ? len - pos : 0)
__set_print_fmt(struct trace_probe * tp,char * buf,int len,enum probe_print_type ptype)874 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
875 			   enum probe_print_type ptype)
876 {
877 	struct probe_arg *parg;
878 	int i, j;
879 	int pos = 0;
880 	const char *fmt, *arg;
881 
882 	switch (ptype) {
883 	case PROBE_PRINT_NORMAL:
884 		fmt = "(%lx)";
885 		arg = ", REC->" FIELD_STRING_IP;
886 		break;
887 	case PROBE_PRINT_RETURN:
888 		fmt = "(%lx <- %lx)";
889 		arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
890 		break;
891 	case PROBE_PRINT_EVENT:
892 		fmt = "";
893 		arg = "";
894 		break;
895 	default:
896 		WARN_ON_ONCE(1);
897 		return 0;
898 	}
899 
900 	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
901 
902 	for (i = 0; i < tp->nr_args; i++) {
903 		parg = tp->args + i;
904 		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
905 		if (parg->count) {
906 			pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
907 					parg->type->fmt);
908 			for (j = 1; j < parg->count; j++)
909 				pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
910 						parg->type->fmt);
911 			pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
912 		} else
913 			pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
914 					parg->type->fmt);
915 	}
916 
917 	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
918 
919 	for (i = 0; i < tp->nr_args; i++) {
920 		parg = tp->args + i;
921 		if (parg->count) {
922 			if ((strcmp(parg->type->name, "string") == 0) ||
923 			    (strcmp(parg->type->name, "ustring") == 0))
924 				fmt = ", __get_str(%s[%d])";
925 			else
926 				fmt = ", REC->%s[%d]";
927 			for (j = 0; j < parg->count; j++)
928 				pos += snprintf(buf + pos, LEN_OR_ZERO,
929 						fmt, parg->name, j);
930 		} else {
931 			if ((strcmp(parg->type->name, "string") == 0) ||
932 			    (strcmp(parg->type->name, "ustring") == 0))
933 				fmt = ", __get_str(%s)";
934 			else
935 				fmt = ", REC->%s";
936 			pos += snprintf(buf + pos, LEN_OR_ZERO,
937 					fmt, parg->name);
938 		}
939 	}
940 
941 	/* return the length of print_fmt */
942 	return pos;
943 }
944 #undef LEN_OR_ZERO
945 
traceprobe_set_print_fmt(struct trace_probe * tp,enum probe_print_type ptype)946 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
947 {
948 	struct trace_event_call *call = trace_probe_event_call(tp);
949 	int len;
950 	char *print_fmt;
951 
952 	/* First: called with 0 length to calculate the needed length */
953 	len = __set_print_fmt(tp, NULL, 0, ptype);
954 	print_fmt = kmalloc(len + 1, GFP_KERNEL);
955 	if (!print_fmt)
956 		return -ENOMEM;
957 
958 	/* Second: actually write the @print_fmt */
959 	__set_print_fmt(tp, print_fmt, len + 1, ptype);
960 	call->print_fmt = print_fmt;
961 
962 	return 0;
963 }
964 
traceprobe_define_arg_fields(struct trace_event_call * event_call,size_t offset,struct trace_probe * tp)965 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
966 				 size_t offset, struct trace_probe *tp)
967 {
968 	int ret, i;
969 
970 	/* Set argument names as fields */
971 	for (i = 0; i < tp->nr_args; i++) {
972 		struct probe_arg *parg = &tp->args[i];
973 		const char *fmt = parg->type->fmttype;
974 		int size = parg->type->size;
975 
976 		if (parg->fmt)
977 			fmt = parg->fmt;
978 		if (parg->count)
979 			size *= parg->count;
980 		ret = trace_define_field(event_call, fmt, parg->name,
981 					 offset + parg->offset, size,
982 					 parg->type->is_signed,
983 					 FILTER_OTHER);
984 		if (ret)
985 			return ret;
986 	}
987 	return 0;
988 }
989 
trace_probe_event_free(struct trace_probe_event * tpe)990 static void trace_probe_event_free(struct trace_probe_event *tpe)
991 {
992 	kfree(tpe->class.system);
993 	kfree(tpe->call.name);
994 	kfree(tpe->call.print_fmt);
995 	kfree(tpe);
996 }
997 
trace_probe_append(struct trace_probe * tp,struct trace_probe * to)998 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
999 {
1000 	if (trace_probe_has_sibling(tp))
1001 		return -EBUSY;
1002 
1003 	list_del_init(&tp->list);
1004 	trace_probe_event_free(tp->event);
1005 
1006 	tp->event = to->event;
1007 	list_add_tail(&tp->list, trace_probe_probe_list(to));
1008 
1009 	return 0;
1010 }
1011 
trace_probe_unlink(struct trace_probe * tp)1012 void trace_probe_unlink(struct trace_probe *tp)
1013 {
1014 	list_del_init(&tp->list);
1015 	if (list_empty(trace_probe_probe_list(tp)))
1016 		trace_probe_event_free(tp->event);
1017 	tp->event = NULL;
1018 }
1019 
trace_probe_cleanup(struct trace_probe * tp)1020 void trace_probe_cleanup(struct trace_probe *tp)
1021 {
1022 	int i;
1023 
1024 	for (i = 0; i < tp->nr_args; i++)
1025 		traceprobe_free_probe_arg(&tp->args[i]);
1026 
1027 	if (tp->event)
1028 		trace_probe_unlink(tp);
1029 }
1030 
trace_probe_init(struct trace_probe * tp,const char * event,const char * group,bool alloc_filter)1031 int trace_probe_init(struct trace_probe *tp, const char *event,
1032 		     const char *group, bool alloc_filter)
1033 {
1034 	struct trace_event_call *call;
1035 	size_t size = sizeof(struct trace_probe_event);
1036 	int ret = 0;
1037 
1038 	if (!event || !group)
1039 		return -EINVAL;
1040 
1041 	if (alloc_filter)
1042 		size += sizeof(struct trace_uprobe_filter);
1043 
1044 	tp->event = kzalloc(size, GFP_KERNEL);
1045 	if (!tp->event)
1046 		return -ENOMEM;
1047 
1048 	INIT_LIST_HEAD(&tp->event->files);
1049 	INIT_LIST_HEAD(&tp->event->class.fields);
1050 	INIT_LIST_HEAD(&tp->event->probes);
1051 	INIT_LIST_HEAD(&tp->list);
1052 	list_add(&tp->list, &tp->event->probes);
1053 
1054 	call = trace_probe_event_call(tp);
1055 	call->class = &tp->event->class;
1056 	call->name = kstrdup(event, GFP_KERNEL);
1057 	if (!call->name) {
1058 		ret = -ENOMEM;
1059 		goto error;
1060 	}
1061 
1062 	tp->event->class.system = kstrdup(group, GFP_KERNEL);
1063 	if (!tp->event->class.system) {
1064 		ret = -ENOMEM;
1065 		goto error;
1066 	}
1067 
1068 	return 0;
1069 
1070 error:
1071 	trace_probe_cleanup(tp);
1072 	return ret;
1073 }
1074 
1075 static struct trace_event_call *
find_trace_event_call(const char * system,const char * event_name)1076 find_trace_event_call(const char *system, const char *event_name)
1077 {
1078 	struct trace_event_call *tp_event;
1079 	const char *name;
1080 
1081 	list_for_each_entry(tp_event, &ftrace_events, list) {
1082 		if (!tp_event->class->system ||
1083 		    strcmp(system, tp_event->class->system))
1084 			continue;
1085 		name = trace_event_name(tp_event);
1086 		if (!name || strcmp(event_name, name))
1087 			continue;
1088 		return tp_event;
1089 	}
1090 
1091 	return NULL;
1092 }
1093 
trace_probe_register_event_call(struct trace_probe * tp)1094 int trace_probe_register_event_call(struct trace_probe *tp)
1095 {
1096 	struct trace_event_call *call = trace_probe_event_call(tp);
1097 	int ret;
1098 
1099 	lockdep_assert_held(&event_mutex);
1100 
1101 	if (find_trace_event_call(trace_probe_group_name(tp),
1102 				  trace_probe_name(tp)))
1103 		return -EEXIST;
1104 
1105 	ret = register_trace_event(&call->event);
1106 	if (!ret)
1107 		return -ENODEV;
1108 
1109 	ret = trace_add_event_call(call);
1110 	if (ret)
1111 		unregister_trace_event(&call->event);
1112 
1113 	return ret;
1114 }
1115 
trace_probe_add_file(struct trace_probe * tp,struct trace_event_file * file)1116 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
1117 {
1118 	struct event_file_link *link;
1119 
1120 	link = kmalloc(sizeof(*link), GFP_KERNEL);
1121 	if (!link)
1122 		return -ENOMEM;
1123 
1124 	link->file = file;
1125 	INIT_LIST_HEAD(&link->list);
1126 	list_add_tail_rcu(&link->list, &tp->event->files);
1127 	trace_probe_set_flag(tp, TP_FLAG_TRACE);
1128 	return 0;
1129 }
1130 
trace_probe_get_file_link(struct trace_probe * tp,struct trace_event_file * file)1131 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
1132 						  struct trace_event_file *file)
1133 {
1134 	struct event_file_link *link;
1135 
1136 	trace_probe_for_each_link(link, tp) {
1137 		if (link->file == file)
1138 			return link;
1139 	}
1140 
1141 	return NULL;
1142 }
1143 
trace_probe_remove_file(struct trace_probe * tp,struct trace_event_file * file)1144 int trace_probe_remove_file(struct trace_probe *tp,
1145 			    struct trace_event_file *file)
1146 {
1147 	struct event_file_link *link;
1148 
1149 	link = trace_probe_get_file_link(tp, file);
1150 	if (!link)
1151 		return -ENOENT;
1152 
1153 	list_del_rcu(&link->list);
1154 	kvfree_rcu(link);
1155 
1156 	if (list_empty(&tp->event->files))
1157 		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
1158 
1159 	return 0;
1160 }
1161 
1162 /*
1163  * Return the smallest index of different type argument (start from 1).
1164  * If all argument types and name are same, return 0.
1165  */
trace_probe_compare_arg_type(struct trace_probe * a,struct trace_probe * b)1166 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
1167 {
1168 	int i;
1169 
1170 	/* In case of more arguments */
1171 	if (a->nr_args < b->nr_args)
1172 		return a->nr_args + 1;
1173 	if (a->nr_args > b->nr_args)
1174 		return b->nr_args + 1;
1175 
1176 	for (i = 0; i < a->nr_args; i++) {
1177 		if ((b->nr_args <= i) ||
1178 		    ((a->args[i].type != b->args[i].type) ||
1179 		     (a->args[i].count != b->args[i].count) ||
1180 		     strcmp(a->args[i].name, b->args[i].name)))
1181 			return i + 1;
1182 	}
1183 
1184 	return 0;
1185 }
1186 
trace_probe_match_command_args(struct trace_probe * tp,int argc,const char ** argv)1187 bool trace_probe_match_command_args(struct trace_probe *tp,
1188 				    int argc, const char **argv)
1189 {
1190 	char buf[MAX_ARGSTR_LEN + 1];
1191 	int i;
1192 
1193 	if (tp->nr_args < argc)
1194 		return false;
1195 
1196 	for (i = 0; i < argc; i++) {
1197 		snprintf(buf, sizeof(buf), "%s=%s",
1198 			 tp->args[i].name, tp->args[i].comm);
1199 		if (strcmp(buf, argv[i]))
1200 			return false;
1201 	}
1202 	return true;
1203 }
1204 
trace_probe_create(const char * raw_command,int (* createfn)(int,const char **))1205 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
1206 {
1207 	int argc = 0, ret = 0;
1208 	char **argv;
1209 
1210 	argv = argv_split(GFP_KERNEL, raw_command, &argc);
1211 	if (!argv)
1212 		return -ENOMEM;
1213 
1214 	if (argc)
1215 		ret = createfn(argc, (const char **)argv);
1216 
1217 	argv_free(argv);
1218 
1219 	return ret;
1220 }
1221