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 <linux/bpf.h>
15 #include "trace_btf.h"
16 
17 #include "trace_probe.h"
18 
19 #undef C
20 #define C(a, b)		b
21 
22 static const char *trace_probe_err_text[] = { ERRORS };
23 
24 static const char *reserved_field_names[] = {
25 	"common_type",
26 	"common_flags",
27 	"common_preempt_count",
28 	"common_pid",
29 	"common_tgid",
30 	FIELD_STRING_IP,
31 	FIELD_STRING_RETIP,
32 	FIELD_STRING_FUNC,
33 };
34 
35 /* Printing  in basic type function template */
36 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)			\
37 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
38 {									\
39 	trace_seq_printf(s, fmt, *(type *)data);			\
40 	return !trace_seq_has_overflowed(s);				\
41 }									\
42 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
43 
44 DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
45 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
46 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
47 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
48 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
49 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
50 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
51 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
52 DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
53 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
54 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
55 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
56 DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
57 
PRINT_TYPE_FUNC_NAME(symbol)58 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
59 {
60 	trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
61 	return !trace_seq_has_overflowed(s);
62 }
63 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
64 
65 /* Print type function for string type */
PRINT_TYPE_FUNC_NAME(string)66 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
67 {
68 	int len = *(u32 *)data >> 16;
69 
70 	if (!len)
71 		trace_seq_puts(s, FAULT_STRING);
72 	else
73 		trace_seq_printf(s, "\"%s\"",
74 				 (const char *)get_loc_data(data, ent));
75 	return !trace_seq_has_overflowed(s);
76 }
77 
78 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
79 
80 /* Fetch type information table */
81 static const struct fetch_type probe_fetch_types[] = {
82 	/* Special types */
83 	__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
84 			    "__data_loc char[]"),
85 	__ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
86 			    "__data_loc char[]"),
87 	__ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
88 			    "__data_loc char[]"),
89 	/* Basic types */
90 	ASSIGN_FETCH_TYPE(u8,  u8,  0),
91 	ASSIGN_FETCH_TYPE(u16, u16, 0),
92 	ASSIGN_FETCH_TYPE(u32, u32, 0),
93 	ASSIGN_FETCH_TYPE(u64, u64, 0),
94 	ASSIGN_FETCH_TYPE(s8,  u8,  1),
95 	ASSIGN_FETCH_TYPE(s16, u16, 1),
96 	ASSIGN_FETCH_TYPE(s32, u32, 1),
97 	ASSIGN_FETCH_TYPE(s64, u64, 1),
98 	ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
99 	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
100 	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
101 	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
102 	ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8,  0),
103 	ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
104 
105 	ASSIGN_FETCH_TYPE_END
106 };
107 
find_fetch_type(const char * type,unsigned long flags)108 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
109 {
110 	int i;
111 
112 	/* Reject the symbol/symstr for uprobes */
113 	if (type && (flags & TPARG_FL_USER) &&
114 	    (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
115 		return NULL;
116 
117 	if (!type)
118 		type = DEFAULT_FETCH_TYPE_STR;
119 
120 	/* Special case: bitfield */
121 	if (*type == 'b') {
122 		unsigned long bs;
123 
124 		type = strchr(type, '/');
125 		if (!type)
126 			goto fail;
127 
128 		type++;
129 		if (kstrtoul(type, 0, &bs))
130 			goto fail;
131 
132 		switch (bs) {
133 		case 8:
134 			return find_fetch_type("u8", flags);
135 		case 16:
136 			return find_fetch_type("u16", flags);
137 		case 32:
138 			return find_fetch_type("u32", flags);
139 		case 64:
140 			return find_fetch_type("u64", flags);
141 		default:
142 			goto fail;
143 		}
144 	}
145 
146 	for (i = 0; probe_fetch_types[i].name; i++) {
147 		if (strcmp(type, probe_fetch_types[i].name) == 0)
148 			return &probe_fetch_types[i];
149 	}
150 
151 fail:
152 	return NULL;
153 }
154 
155 static struct trace_probe_log trace_probe_log;
156 
trace_probe_log_init(const char * subsystem,int argc,const char ** argv)157 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
158 {
159 	trace_probe_log.subsystem = subsystem;
160 	trace_probe_log.argc = argc;
161 	trace_probe_log.argv = argv;
162 	trace_probe_log.index = 0;
163 }
164 
trace_probe_log_clear(void)165 void trace_probe_log_clear(void)
166 {
167 	memset(&trace_probe_log, 0, sizeof(trace_probe_log));
168 }
169 
trace_probe_log_set_index(int index)170 void trace_probe_log_set_index(int index)
171 {
172 	trace_probe_log.index = index;
173 }
174 
__trace_probe_log_err(int offset,int err_type)175 void __trace_probe_log_err(int offset, int err_type)
176 {
177 	char *command, *p;
178 	int i, len = 0, pos = 0;
179 
180 	if (!trace_probe_log.argv)
181 		return;
182 
183 	/* Recalculate the length and allocate buffer */
184 	for (i = 0; i < trace_probe_log.argc; i++) {
185 		if (i == trace_probe_log.index)
186 			pos = len;
187 		len += strlen(trace_probe_log.argv[i]) + 1;
188 	}
189 	command = kzalloc(len, GFP_KERNEL);
190 	if (!command)
191 		return;
192 
193 	if (trace_probe_log.index >= trace_probe_log.argc) {
194 		/**
195 		 * Set the error position is next to the last arg + space.
196 		 * Note that len includes the terminal null and the cursor
197 		 * appears at pos + 1.
198 		 */
199 		pos = len;
200 		offset = 0;
201 	}
202 
203 	/* And make a command string from argv array */
204 	p = command;
205 	for (i = 0; i < trace_probe_log.argc; i++) {
206 		len = strlen(trace_probe_log.argv[i]);
207 		strcpy(p, trace_probe_log.argv[i]);
208 		p[len] = ' ';
209 		p += len + 1;
210 	}
211 	*(p - 1) = '\0';
212 
213 	tracing_log_err(NULL, trace_probe_log.subsystem, command,
214 			trace_probe_err_text, err_type, pos + offset);
215 
216 	kfree(command);
217 }
218 
219 /* Split symbol and offset. */
traceprobe_split_symbol_offset(char * symbol,long * offset)220 int traceprobe_split_symbol_offset(char *symbol, long *offset)
221 {
222 	char *tmp;
223 	int ret;
224 
225 	if (!offset)
226 		return -EINVAL;
227 
228 	tmp = strpbrk(symbol, "+-");
229 	if (tmp) {
230 		ret = kstrtol(tmp, 0, offset);
231 		if (ret)
232 			return ret;
233 		*tmp = '\0';
234 	} else
235 		*offset = 0;
236 
237 	return 0;
238 }
239 
240 /* @buf must has MAX_EVENT_NAME_LEN size */
traceprobe_parse_event_name(const char ** pevent,const char ** pgroup,char * buf,int offset)241 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
242 				char *buf, int offset)
243 {
244 	const char *slash, *event = *pevent;
245 	int len;
246 
247 	slash = strchr(event, '/');
248 	if (!slash)
249 		slash = strchr(event, '.');
250 
251 	if (slash) {
252 		if (slash == event) {
253 			trace_probe_log_err(offset, NO_GROUP_NAME);
254 			return -EINVAL;
255 		}
256 		if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
257 			trace_probe_log_err(offset, GROUP_TOO_LONG);
258 			return -EINVAL;
259 		}
260 		strscpy(buf, event, slash - event + 1);
261 		if (!is_good_system_name(buf)) {
262 			trace_probe_log_err(offset, BAD_GROUP_NAME);
263 			return -EINVAL;
264 		}
265 		*pgroup = buf;
266 		*pevent = slash + 1;
267 		offset += slash - event + 1;
268 		event = *pevent;
269 	}
270 	len = strlen(event);
271 	if (len == 0) {
272 		if (slash) {
273 			*pevent = NULL;
274 			return 0;
275 		}
276 		trace_probe_log_err(offset, NO_EVENT_NAME);
277 		return -EINVAL;
278 	} else if (len > MAX_EVENT_NAME_LEN) {
279 		trace_probe_log_err(offset, EVENT_TOO_LONG);
280 		return -EINVAL;
281 	}
282 	if (!is_good_name(event)) {
283 		trace_probe_log_err(offset, BAD_EVENT_NAME);
284 		return -EINVAL;
285 	}
286 	return 0;
287 }
288 
parse_trace_event_arg(char * arg,struct fetch_insn * code,struct traceprobe_parse_context * ctx)289 static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
290 				 struct traceprobe_parse_context *ctx)
291 {
292 	struct ftrace_event_field *field;
293 	struct list_head *head;
294 
295 	head = trace_get_fields(ctx->event);
296 	list_for_each_entry(field, head, link) {
297 		if (!strcmp(arg, field->name)) {
298 			code->op = FETCH_OP_TP_ARG;
299 			code->data = field;
300 			return 0;
301 		}
302 	}
303 	return -ENOENT;
304 }
305 
306 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
307 
btf_type_int(const struct btf_type * t)308 static u32 btf_type_int(const struct btf_type *t)
309 {
310 	return *(u32 *)(t + 1);
311 }
312 
btf_type_is_char_ptr(struct btf * btf,const struct btf_type * type)313 static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type)
314 {
315 	const struct btf_type *real_type;
316 	u32 intdata;
317 	s32 tid;
318 
319 	real_type = btf_type_skip_modifiers(btf, type->type, &tid);
320 	if (!real_type)
321 		return false;
322 
323 	if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT)
324 		return false;
325 
326 	intdata = btf_type_int(real_type);
327 	return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
328 		&& BTF_INT_BITS(intdata) == 8;
329 }
330 
btf_type_is_char_array(struct btf * btf,const struct btf_type * type)331 static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
332 {
333 	const struct btf_type *real_type;
334 	const struct btf_array *array;
335 	u32 intdata;
336 	s32 tid;
337 
338 	if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY)
339 		return false;
340 
341 	array = (const struct btf_array *)(type + 1);
342 
343 	real_type = btf_type_skip_modifiers(btf, array->type, &tid);
344 
345 	intdata = btf_type_int(real_type);
346 	return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
347 		&& BTF_INT_BITS(intdata) == 8;
348 }
349 
check_prepare_btf_string_fetch(char * typename,struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)350 static int check_prepare_btf_string_fetch(char *typename,
351 				struct fetch_insn **pcode,
352 				struct traceprobe_parse_context *ctx)
353 {
354 	struct btf *btf = ctx->btf;
355 
356 	if (!btf || !ctx->last_type)
357 		return 0;
358 
359 	/* char [] does not need any change. */
360 	if (btf_type_is_char_array(btf, ctx->last_type))
361 		return 0;
362 
363 	/* char * requires dereference the pointer. */
364 	if (btf_type_is_char_ptr(btf, ctx->last_type)) {
365 		struct fetch_insn *code = *pcode + 1;
366 
367 		if (code->op == FETCH_OP_END) {
368 			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
369 			return -E2BIG;
370 		}
371 		if (typename[0] == 'u')
372 			code->op = FETCH_OP_UDEREF;
373 		else
374 			code->op = FETCH_OP_DEREF;
375 		code->offset = 0;
376 		*pcode = code;
377 		return 0;
378 	}
379 	/* Other types are not available for string */
380 	trace_probe_log_err(ctx->offset, BAD_TYPE4STR);
381 	return -EINVAL;
382 }
383 
fetch_type_from_btf_type(struct btf * btf,const struct btf_type * type,struct traceprobe_parse_context * ctx)384 static const char *fetch_type_from_btf_type(struct btf *btf,
385 					const struct btf_type *type,
386 					struct traceprobe_parse_context *ctx)
387 {
388 	u32 intdata;
389 
390 	/* TODO: const char * could be converted as a string */
391 	switch (BTF_INFO_KIND(type->info)) {
392 	case BTF_KIND_ENUM:
393 		/* enum is "int", so convert to "s32" */
394 		return "s32";
395 	case BTF_KIND_ENUM64:
396 		return "s64";
397 	case BTF_KIND_PTR:
398 		/* pointer will be converted to "x??" */
399 		if (IS_ENABLED(CONFIG_64BIT))
400 			return "x64";
401 		else
402 			return "x32";
403 	case BTF_KIND_INT:
404 		intdata = btf_type_int(type);
405 		if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
406 			switch (BTF_INT_BITS(intdata)) {
407 			case 8:
408 				return "s8";
409 			case 16:
410 				return "s16";
411 			case 32:
412 				return "s32";
413 			case 64:
414 				return "s64";
415 			}
416 		} else {	/* unsigned */
417 			switch (BTF_INT_BITS(intdata)) {
418 			case 8:
419 				return "u8";
420 			case 16:
421 				return "u16";
422 			case 32:
423 				return "u32";
424 			case 64:
425 				return "u64";
426 			}
427 			/* bitfield, size is encoded in the type */
428 			ctx->last_bitsize = BTF_INT_BITS(intdata);
429 			ctx->last_bitoffs += BTF_INT_OFFSET(intdata);
430 			return "u64";
431 		}
432 	}
433 	/* TODO: support other types */
434 
435 	return NULL;
436 }
437 
query_btf_context(struct traceprobe_parse_context * ctx)438 static int query_btf_context(struct traceprobe_parse_context *ctx)
439 {
440 	const struct btf_param *param;
441 	const struct btf_type *type;
442 	struct btf *btf;
443 	s32 nr;
444 
445 	if (ctx->btf)
446 		return 0;
447 
448 	if (!ctx->funcname)
449 		return -EINVAL;
450 
451 	type = btf_find_func_proto(ctx->funcname, &btf);
452 	if (!type)
453 		return -ENOENT;
454 
455 	ctx->btf = btf;
456 	ctx->proto = type;
457 
458 	/* ctx->params is optional, since func(void) will not have params. */
459 	nr = 0;
460 	param = btf_get_func_param(type, &nr);
461 	if (!IS_ERR_OR_NULL(param)) {
462 		/* Hide the first 'data' argument of tracepoint */
463 		if (ctx->flags & TPARG_FL_TPOINT) {
464 			nr--;
465 			param++;
466 		}
467 	}
468 
469 	if (nr > 0) {
470 		ctx->nr_params = nr;
471 		ctx->params = param;
472 	} else {
473 		ctx->nr_params = 0;
474 		ctx->params = NULL;
475 	}
476 
477 	return 0;
478 }
479 
clear_btf_context(struct traceprobe_parse_context * ctx)480 static void clear_btf_context(struct traceprobe_parse_context *ctx)
481 {
482 	if (ctx->btf) {
483 		btf_put(ctx->btf);
484 		ctx->btf = NULL;
485 		ctx->proto = NULL;
486 		ctx->params = NULL;
487 		ctx->nr_params = 0;
488 	}
489 }
490 
491 /* Return 1 if the field separater is arrow operator ('->') */
split_next_field(char * varname,char ** next_field,struct traceprobe_parse_context * ctx)492 static int split_next_field(char *varname, char **next_field,
493 			    struct traceprobe_parse_context *ctx)
494 {
495 	char *field;
496 	int ret = 0;
497 
498 	field = strpbrk(varname, ".-");
499 	if (field) {
500 		if (field[0] == '-' && field[1] == '>') {
501 			field[0] = '\0';
502 			field += 2;
503 			ret = 1;
504 		} else if (field[0] == '.') {
505 			field[0] = '\0';
506 			field += 1;
507 		} else {
508 			trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN);
509 			return -EINVAL;
510 		}
511 		*next_field = field;
512 	}
513 
514 	return ret;
515 }
516 
517 /*
518  * Parse the field of data structure. The @type must be a pointer type
519  * pointing the target data structure type.
520  */
parse_btf_field(char * fieldname,const struct btf_type * type,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)521 static int parse_btf_field(char *fieldname, const struct btf_type *type,
522 			   struct fetch_insn **pcode, struct fetch_insn *end,
523 			   struct traceprobe_parse_context *ctx)
524 {
525 	struct fetch_insn *code = *pcode;
526 	const struct btf_member *field;
527 	u32 bitoffs, anon_offs;
528 	char *next;
529 	int is_ptr;
530 	s32 tid;
531 
532 	do {
533 		/* Outer loop for solving arrow operator ('->') */
534 		if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
535 			trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
536 			return -EINVAL;
537 		}
538 		/* Convert a struct pointer type to a struct type */
539 		type = btf_type_skip_modifiers(ctx->btf, type->type, &tid);
540 		if (!type) {
541 			trace_probe_log_err(ctx->offset, BAD_BTF_TID);
542 			return -EINVAL;
543 		}
544 
545 		bitoffs = 0;
546 		do {
547 			/* Inner loop for solving dot operator ('.') */
548 			next = NULL;
549 			is_ptr = split_next_field(fieldname, &next, ctx);
550 			if (is_ptr < 0)
551 				return is_ptr;
552 
553 			anon_offs = 0;
554 			field = btf_find_struct_member(ctx->btf, type, fieldname,
555 						       &anon_offs);
556 			if (!field) {
557 				trace_probe_log_err(ctx->offset, NO_BTF_FIELD);
558 				return -ENOENT;
559 			}
560 			/* Add anonymous structure/union offset */
561 			bitoffs += anon_offs;
562 
563 			/* Accumulate the bit-offsets of the dot-connected fields */
564 			if (btf_type_kflag(type)) {
565 				bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset);
566 				ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset);
567 			} else {
568 				bitoffs += field->offset;
569 				ctx->last_bitsize = 0;
570 			}
571 
572 			type = btf_type_skip_modifiers(ctx->btf, field->type, &tid);
573 			if (!type) {
574 				trace_probe_log_err(ctx->offset, BAD_BTF_TID);
575 				return -EINVAL;
576 			}
577 
578 			ctx->offset += next - fieldname;
579 			fieldname = next;
580 		} while (!is_ptr && fieldname);
581 
582 		if (++code == end) {
583 			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
584 			return -EINVAL;
585 		}
586 		code->op = FETCH_OP_DEREF;	/* TODO: user deref support */
587 		code->offset = bitoffs / 8;
588 		*pcode = code;
589 
590 		ctx->last_bitoffs = bitoffs % 8;
591 		ctx->last_type = type;
592 	} while (fieldname);
593 
594 	return 0;
595 }
596 
parse_btf_arg(char * varname,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)597 static int parse_btf_arg(char *varname,
598 			 struct fetch_insn **pcode, struct fetch_insn *end,
599 			 struct traceprobe_parse_context *ctx)
600 {
601 	struct fetch_insn *code = *pcode;
602 	const struct btf_param *params;
603 	const struct btf_type *type;
604 	char *field = NULL;
605 	int i, is_ptr, ret;
606 	u32 tid;
607 
608 	if (WARN_ON_ONCE(!ctx->funcname))
609 		return -EINVAL;
610 
611 	is_ptr = split_next_field(varname, &field, ctx);
612 	if (is_ptr < 0)
613 		return is_ptr;
614 	if (!is_ptr && field) {
615 		/* dot-connected field on an argument is not supported. */
616 		trace_probe_log_err(ctx->offset + field - varname,
617 				    NOSUP_DAT_ARG);
618 		return -EOPNOTSUPP;
619 	}
620 
621 	if (ctx->flags & TPARG_FL_RETURN) {
622 		if (strcmp(varname, "$retval") != 0) {
623 			trace_probe_log_err(ctx->offset, NO_BTFARG);
624 			return -ENOENT;
625 		}
626 		code->op = FETCH_OP_RETVAL;
627 		/* Check whether the function return type is not void */
628 		if (query_btf_context(ctx) == 0) {
629 			if (ctx->proto->type == 0) {
630 				trace_probe_log_err(ctx->offset, NO_RETVAL);
631 				return -ENOENT;
632 			}
633 			tid = ctx->proto->type;
634 			goto found;
635 		}
636 		if (field) {
637 			trace_probe_log_err(ctx->offset + field - varname,
638 					    NO_BTF_ENTRY);
639 			return -ENOENT;
640 		}
641 		return 0;
642 	}
643 
644 	if (!ctx->btf) {
645 		ret = query_btf_context(ctx);
646 		if (ret < 0 || ctx->nr_params == 0) {
647 			trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
648 			return PTR_ERR(params);
649 		}
650 	}
651 	params = ctx->params;
652 
653 	for (i = 0; i < ctx->nr_params; i++) {
654 		const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
655 
656 		if (name && !strcmp(name, varname)) {
657 			code->op = FETCH_OP_ARG;
658 			if (ctx->flags & TPARG_FL_TPOINT)
659 				code->param = i + 1;
660 			else
661 				code->param = i;
662 			tid = params[i].type;
663 			goto found;
664 		}
665 	}
666 	trace_probe_log_err(ctx->offset, NO_BTFARG);
667 	return -ENOENT;
668 
669 found:
670 	type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
671 	if (!type) {
672 		trace_probe_log_err(ctx->offset, BAD_BTF_TID);
673 		return -EINVAL;
674 	}
675 	/* Initialize the last type information */
676 	ctx->last_type = type;
677 	ctx->last_bitoffs = 0;
678 	ctx->last_bitsize = 0;
679 	if (field) {
680 		ctx->offset += field - varname;
681 		return parse_btf_field(field, type, pcode, end, ctx);
682 	}
683 	return 0;
684 }
685 
find_fetch_type_from_btf_type(struct traceprobe_parse_context * ctx)686 static const struct fetch_type *find_fetch_type_from_btf_type(
687 					struct traceprobe_parse_context *ctx)
688 {
689 	struct btf *btf = ctx->btf;
690 	const char *typestr = NULL;
691 
692 	if (btf && ctx->last_type)
693 		typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
694 
695 	return find_fetch_type(typestr, ctx->flags);
696 }
697 
parse_btf_bitfield(struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)698 static int parse_btf_bitfield(struct fetch_insn **pcode,
699 			      struct traceprobe_parse_context *ctx)
700 {
701 	struct fetch_insn *code = *pcode;
702 
703 	if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0)
704 		return 0;
705 
706 	code++;
707 	if (code->op != FETCH_OP_NOP) {
708 		trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
709 		return -EINVAL;
710 	}
711 	*pcode = code;
712 
713 	code->op = FETCH_OP_MOD_BF;
714 	code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs);
715 	code->rshift = 64 - ctx->last_bitsize;
716 	code->basesize = 64 / 8;
717 	return 0;
718 }
719 
720 #else
clear_btf_context(struct traceprobe_parse_context * ctx)721 static void clear_btf_context(struct traceprobe_parse_context *ctx)
722 {
723 	ctx->btf = NULL;
724 }
725 
query_btf_context(struct traceprobe_parse_context * ctx)726 static int query_btf_context(struct traceprobe_parse_context *ctx)
727 {
728 	return -EOPNOTSUPP;
729 }
730 
parse_btf_arg(char * varname,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)731 static int parse_btf_arg(char *varname,
732 			 struct fetch_insn **pcode, struct fetch_insn *end,
733 			 struct traceprobe_parse_context *ctx)
734 {
735 	trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
736 	return -EOPNOTSUPP;
737 }
738 
parse_btf_bitfield(struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)739 static int parse_btf_bitfield(struct fetch_insn **pcode,
740 			      struct traceprobe_parse_context *ctx)
741 {
742 	trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
743 	return -EOPNOTSUPP;
744 }
745 
746 #define find_fetch_type_from_btf_type(ctx)		\
747 	find_fetch_type(NULL, ctx->flags)
748 
check_prepare_btf_string_fetch(char * typename,struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)749 static int check_prepare_btf_string_fetch(char *typename,
750 				struct fetch_insn **pcode,
751 				struct traceprobe_parse_context *ctx)
752 {
753 	return 0;
754 }
755 
756 #endif
757 
758 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
759 
760 /* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
parse_probe_vars(char * orig_arg,const struct fetch_type * t,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)761 static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
762 			    struct fetch_insn **pcode,
763 			    struct fetch_insn *end,
764 			    struct traceprobe_parse_context *ctx)
765 {
766 	struct fetch_insn *code = *pcode;
767 	int err = TP_ERR_BAD_VAR;
768 	char *arg = orig_arg + 1;
769 	unsigned long param;
770 	int ret = 0;
771 	int len;
772 
773 	if (ctx->flags & TPARG_FL_TEVENT) {
774 		if (code->data)
775 			return -EFAULT;
776 		ret = parse_trace_event_arg(arg, code, ctx);
777 		if (!ret)
778 			return 0;
779 		if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
780 			code->op = FETCH_OP_COMM;
781 			return 0;
782 		}
783 		/* backward compatibility */
784 		ctx->offset = 0;
785 		goto inval;
786 	}
787 
788 	if (str_has_prefix(arg, "retval")) {
789 		if (!(ctx->flags & TPARG_FL_RETURN)) {
790 			err = TP_ERR_RETVAL_ON_PROBE;
791 			goto inval;
792 		}
793 		if (!(ctx->flags & TPARG_FL_KERNEL) ||
794 		    !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
795 			code->op = FETCH_OP_RETVAL;
796 			return 0;
797 		}
798 		return parse_btf_arg(orig_arg, pcode, end, ctx);
799 	}
800 
801 	len = str_has_prefix(arg, "stack");
802 	if (len) {
803 
804 		if (arg[len] == '\0') {
805 			code->op = FETCH_OP_STACKP;
806 			return 0;
807 		}
808 
809 		if (isdigit(arg[len])) {
810 			ret = kstrtoul(arg + len, 10, &param);
811 			if (ret)
812 				goto inval;
813 
814 			if ((ctx->flags & TPARG_FL_KERNEL) &&
815 			    param > PARAM_MAX_STACK) {
816 				err = TP_ERR_BAD_STACK_NUM;
817 				goto inval;
818 			}
819 			code->op = FETCH_OP_STACK;
820 			code->param = (unsigned int)param;
821 			return 0;
822 		}
823 		goto inval;
824 	}
825 
826 	if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
827 		code->op = FETCH_OP_COMM;
828 		return 0;
829 	}
830 
831 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
832 	len = str_has_prefix(arg, "arg");
833 	if (len && tparg_is_function_entry(ctx->flags)) {
834 		ret = kstrtoul(arg + len, 10, &param);
835 		if (ret)
836 			goto inval;
837 
838 		if (!param || param > PARAM_MAX_STACK) {
839 			err = TP_ERR_BAD_ARG_NUM;
840 			goto inval;
841 		}
842 
843 		code->op = FETCH_OP_ARG;
844 		code->param = (unsigned int)param - 1;
845 		/*
846 		 * The tracepoint probe will probe a stub function, and the
847 		 * first parameter of the stub is a dummy and should be ignored.
848 		 */
849 		if (ctx->flags & TPARG_FL_TPOINT)
850 			code->param++;
851 		return 0;
852 	}
853 #endif
854 
855 inval:
856 	__trace_probe_log_err(ctx->offset, err);
857 	return -EINVAL;
858 }
859 
str_to_immediate(char * str,unsigned long * imm)860 static int str_to_immediate(char *str, unsigned long *imm)
861 {
862 	if (isdigit(str[0]))
863 		return kstrtoul(str, 0, imm);
864 	else if (str[0] == '-')
865 		return kstrtol(str, 0, (long *)imm);
866 	else if (str[0] == '+')
867 		return kstrtol(str + 1, 0, (long *)imm);
868 	return -EINVAL;
869 }
870 
__parse_imm_string(char * str,char ** pbuf,int offs)871 static int __parse_imm_string(char *str, char **pbuf, int offs)
872 {
873 	size_t len = strlen(str);
874 
875 	if (str[len - 1] != '"') {
876 		trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
877 		return -EINVAL;
878 	}
879 	*pbuf = kstrndup(str, len - 1, GFP_KERNEL);
880 	if (!*pbuf)
881 		return -ENOMEM;
882 	return 0;
883 }
884 
885 /* Recursive argument parser */
886 static int
parse_probe_arg(char * arg,const struct fetch_type * type,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)887 parse_probe_arg(char *arg, const struct fetch_type *type,
888 		struct fetch_insn **pcode, struct fetch_insn *end,
889 		struct traceprobe_parse_context *ctx)
890 {
891 	struct fetch_insn *code = *pcode;
892 	unsigned long param;
893 	int deref = FETCH_OP_DEREF;
894 	long offset = 0;
895 	char *tmp;
896 	int ret = 0;
897 
898 	switch (arg[0]) {
899 	case '$':
900 		ret = parse_probe_vars(arg, type, pcode, end, ctx);
901 		break;
902 
903 	case '%':	/* named register */
904 		if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
905 			/* eprobe and fprobe do not handle registers */
906 			trace_probe_log_err(ctx->offset, BAD_VAR);
907 			break;
908 		}
909 		ret = regs_query_register_offset(arg + 1);
910 		if (ret >= 0) {
911 			code->op = FETCH_OP_REG;
912 			code->param = (unsigned int)ret;
913 			ret = 0;
914 		} else
915 			trace_probe_log_err(ctx->offset, BAD_REG_NAME);
916 		break;
917 
918 	case '@':	/* memory, file-offset or symbol */
919 		if (isdigit(arg[1])) {
920 			ret = kstrtoul(arg + 1, 0, &param);
921 			if (ret) {
922 				trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
923 				break;
924 			}
925 			/* load address */
926 			code->op = FETCH_OP_IMM;
927 			code->immediate = param;
928 		} else if (arg[1] == '+') {
929 			/* kprobes don't support file offsets */
930 			if (ctx->flags & TPARG_FL_KERNEL) {
931 				trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
932 				return -EINVAL;
933 			}
934 			ret = kstrtol(arg + 2, 0, &offset);
935 			if (ret) {
936 				trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
937 				break;
938 			}
939 
940 			code->op = FETCH_OP_FOFFS;
941 			code->immediate = (unsigned long)offset;  // imm64?
942 		} else {
943 			/* uprobes don't support symbols */
944 			if (!(ctx->flags & TPARG_FL_KERNEL)) {
945 				trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
946 				return -EINVAL;
947 			}
948 			/* Preserve symbol for updating */
949 			code->op = FETCH_NOP_SYMBOL;
950 			code->data = kstrdup(arg + 1, GFP_KERNEL);
951 			if (!code->data)
952 				return -ENOMEM;
953 			if (++code == end) {
954 				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
955 				return -EINVAL;
956 			}
957 			code->op = FETCH_OP_IMM;
958 			code->immediate = 0;
959 		}
960 		/* These are fetching from memory */
961 		if (++code == end) {
962 			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
963 			return -EINVAL;
964 		}
965 		*pcode = code;
966 		code->op = FETCH_OP_DEREF;
967 		code->offset = offset;
968 		break;
969 
970 	case '+':	/* deref memory */
971 	case '-':
972 		if (arg[1] == 'u') {
973 			deref = FETCH_OP_UDEREF;
974 			arg[1] = arg[0];
975 			arg++;
976 		}
977 		if (arg[0] == '+')
978 			arg++;	/* Skip '+', because kstrtol() rejects it. */
979 		tmp = strchr(arg, '(');
980 		if (!tmp) {
981 			trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
982 			return -EINVAL;
983 		}
984 		*tmp = '\0';
985 		ret = kstrtol(arg, 0, &offset);
986 		if (ret) {
987 			trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
988 			break;
989 		}
990 		ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
991 		arg = tmp + 1;
992 		tmp = strrchr(arg, ')');
993 		if (!tmp) {
994 			trace_probe_log_err(ctx->offset + strlen(arg),
995 					    DEREF_OPEN_BRACE);
996 			return -EINVAL;
997 		} else {
998 			const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
999 			int cur_offs = ctx->offset;
1000 
1001 			*tmp = '\0';
1002 			ret = parse_probe_arg(arg, t2, &code, end, ctx);
1003 			if (ret)
1004 				break;
1005 			ctx->offset = cur_offs;
1006 			if (code->op == FETCH_OP_COMM ||
1007 			    code->op == FETCH_OP_DATA) {
1008 				trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
1009 				return -EINVAL;
1010 			}
1011 			if (++code == end) {
1012 				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1013 				return -EINVAL;
1014 			}
1015 			*pcode = code;
1016 
1017 			code->op = deref;
1018 			code->offset = offset;
1019 			/* Reset the last type if used */
1020 			ctx->last_type = NULL;
1021 		}
1022 		break;
1023 	case '\\':	/* Immediate value */
1024 		if (arg[1] == '"') {	/* Immediate string */
1025 			ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
1026 			if (ret)
1027 				break;
1028 			code->op = FETCH_OP_DATA;
1029 			code->data = tmp;
1030 		} else {
1031 			ret = str_to_immediate(arg + 1, &code->immediate);
1032 			if (ret)
1033 				trace_probe_log_err(ctx->offset + 1, BAD_IMM);
1034 			else
1035 				code->op = FETCH_OP_IMM;
1036 		}
1037 		break;
1038 	default:
1039 		if (isalpha(arg[0]) || arg[0] == '_') {	/* BTF variable */
1040 			if (!tparg_is_function_entry(ctx->flags)) {
1041 				trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
1042 				return -EINVAL;
1043 			}
1044 			ret = parse_btf_arg(arg, pcode, end, ctx);
1045 			break;
1046 		}
1047 	}
1048 	if (!ret && code->op == FETCH_OP_NOP) {
1049 		/* Parsed, but do not find fetch method */
1050 		trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
1051 		ret = -EINVAL;
1052 	}
1053 	return ret;
1054 }
1055 
1056 #define BYTES_TO_BITS(nb)	((BITS_PER_LONG * (nb)) / sizeof(long))
1057 
1058 /* 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)1059 static int __parse_bitfield_probe_arg(const char *bf,
1060 				      const struct fetch_type *t,
1061 				      struct fetch_insn **pcode)
1062 {
1063 	struct fetch_insn *code = *pcode;
1064 	unsigned long bw, bo;
1065 	char *tail;
1066 
1067 	if (*bf != 'b')
1068 		return 0;
1069 
1070 	bw = simple_strtoul(bf + 1, &tail, 0);	/* Use simple one */
1071 
1072 	if (bw == 0 || *tail != '@')
1073 		return -EINVAL;
1074 
1075 	bf = tail + 1;
1076 	bo = simple_strtoul(bf, &tail, 0);
1077 
1078 	if (tail == bf || *tail != '/')
1079 		return -EINVAL;
1080 	code++;
1081 	if (code->op != FETCH_OP_NOP)
1082 		return -EINVAL;
1083 	*pcode = code;
1084 
1085 	code->op = FETCH_OP_MOD_BF;
1086 	code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
1087 	code->rshift = BYTES_TO_BITS(t->size) - bw;
1088 	code->basesize = t->size;
1089 
1090 	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1091 }
1092 
1093 /* String length checking wrapper */
traceprobe_parse_probe_arg_body(const char * argv,ssize_t * size,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1094 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
1095 					   struct probe_arg *parg,
1096 					   struct traceprobe_parse_context *ctx)
1097 {
1098 	struct fetch_insn *code, *scode, *tmp = NULL;
1099 	char *t, *t2, *t3;
1100 	int ret, len;
1101 	char *arg;
1102 
1103 	arg = kstrdup(argv, GFP_KERNEL);
1104 	if (!arg)
1105 		return -ENOMEM;
1106 
1107 	ret = -EINVAL;
1108 	len = strlen(arg);
1109 	if (len > MAX_ARGSTR_LEN) {
1110 		trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
1111 		goto out;
1112 	} else if (len == 0) {
1113 		trace_probe_log_err(ctx->offset, NO_ARG_BODY);
1114 		goto out;
1115 	}
1116 
1117 	ret = -ENOMEM;
1118 	parg->comm = kstrdup(arg, GFP_KERNEL);
1119 	if (!parg->comm)
1120 		goto out;
1121 
1122 	ret = -EINVAL;
1123 	t = strchr(arg, ':');
1124 	if (t) {
1125 		*t = '\0';
1126 		t2 = strchr(++t, '[');
1127 		if (t2) {
1128 			*t2++ = '\0';
1129 			t3 = strchr(t2, ']');
1130 			if (!t3) {
1131 				int offs = t2 + strlen(t2) - arg;
1132 
1133 				trace_probe_log_err(ctx->offset + offs,
1134 						    ARRAY_NO_CLOSE);
1135 				goto out;
1136 			} else if (t3[1] != '\0') {
1137 				trace_probe_log_err(ctx->offset + t3 + 1 - arg,
1138 						    BAD_ARRAY_SUFFIX);
1139 				goto out;
1140 			}
1141 			*t3 = '\0';
1142 			if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
1143 				trace_probe_log_err(ctx->offset + t2 - arg,
1144 						    BAD_ARRAY_NUM);
1145 				goto out;
1146 			}
1147 			if (parg->count > MAX_ARRAY_LEN) {
1148 				trace_probe_log_err(ctx->offset + t2 - arg,
1149 						    ARRAY_TOO_BIG);
1150 				goto out;
1151 			}
1152 		}
1153 	}
1154 
1155 	/*
1156 	 * Since $comm and immediate string can not be dereferenced,
1157 	 * we can find those by strcmp. But ignore for eprobes.
1158 	 */
1159 	if (!(ctx->flags & TPARG_FL_TEVENT) &&
1160 	    (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
1161 	     strncmp(arg, "\\\"", 2) == 0)) {
1162 		/* The type of $comm must be "string", and not an array type. */
1163 		if (parg->count || (t && strcmp(t, "string"))) {
1164 			trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
1165 					NEED_STRING_TYPE);
1166 			goto out;
1167 		}
1168 		parg->type = find_fetch_type("string", ctx->flags);
1169 	} else
1170 		parg->type = find_fetch_type(t, ctx->flags);
1171 	if (!parg->type) {
1172 		trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0), BAD_TYPE);
1173 		goto out;
1174 	}
1175 
1176 	code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
1177 	if (!code)
1178 		goto out;
1179 	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
1180 
1181 	ctx->last_type = NULL;
1182 	ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
1183 			      ctx);
1184 	if (ret)
1185 		goto fail;
1186 
1187 	/* Update storing type if BTF is available */
1188 	if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1189 	    ctx->last_type) {
1190 		if (!t) {
1191 			parg->type = find_fetch_type_from_btf_type(ctx);
1192 		} else if (strstr(t, "string")) {
1193 			ret = check_prepare_btf_string_fetch(t, &code, ctx);
1194 			if (ret)
1195 				goto fail;
1196 		}
1197 	}
1198 	parg->offset = *size;
1199 	*size += parg->type->size * (parg->count ?: 1);
1200 
1201 	if (parg->count) {
1202 		len = strlen(parg->type->fmttype) + 6;
1203 		parg->fmt = kmalloc(len, GFP_KERNEL);
1204 		if (!parg->fmt) {
1205 			ret = -ENOMEM;
1206 			goto out;
1207 		}
1208 		snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
1209 			 parg->count);
1210 	}
1211 
1212 	ret = -EINVAL;
1213 	/* Store operation */
1214 	if (parg->type->is_string) {
1215 		if (!strcmp(parg->type->name, "symstr")) {
1216 			if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
1217 			    code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
1218 			    code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
1219 				trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
1220 						    BAD_SYMSTRING);
1221 				goto fail;
1222 			}
1223 		} else {
1224 			if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
1225 			    code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
1226 			    code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
1227 				trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
1228 						    BAD_STRING);
1229 				goto fail;
1230 			}
1231 		}
1232 		if (!strcmp(parg->type->name, "symstr") ||
1233 		    (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1234 		     code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1235 		     parg->count) {
1236 			/*
1237 			 * IMM, DATA and COMM is pointing actual address, those
1238 			 * must be kept, and if parg->count != 0, this is an
1239 			 * array of string pointers instead of string address
1240 			 * itself.
1241 			 * For the symstr, it doesn't need to dereference, thus
1242 			 * it just get the value.
1243 			 */
1244 			code++;
1245 			if (code->op != FETCH_OP_NOP) {
1246 				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1247 				goto fail;
1248 			}
1249 		}
1250 		/* If op == DEREF, replace it with STRING */
1251 		if (!strcmp(parg->type->name, "ustring") ||
1252 		    code->op == FETCH_OP_UDEREF)
1253 			code->op = FETCH_OP_ST_USTRING;
1254 		else if (!strcmp(parg->type->name, "symstr"))
1255 			code->op = FETCH_OP_ST_SYMSTR;
1256 		else
1257 			code->op = FETCH_OP_ST_STRING;
1258 		code->size = parg->type->size;
1259 		parg->dynamic = true;
1260 	} else if (code->op == FETCH_OP_DEREF) {
1261 		code->op = FETCH_OP_ST_MEM;
1262 		code->size = parg->type->size;
1263 	} else if (code->op == FETCH_OP_UDEREF) {
1264 		code->op = FETCH_OP_ST_UMEM;
1265 		code->size = parg->type->size;
1266 	} else {
1267 		code++;
1268 		if (code->op != FETCH_OP_NOP) {
1269 			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1270 			goto fail;
1271 		}
1272 		code->op = FETCH_OP_ST_RAW;
1273 		code->size = parg->type->size;
1274 	}
1275 	scode = code;
1276 	/* Modify operation */
1277 	if (t != NULL) {
1278 		ret = __parse_bitfield_probe_arg(t, parg->type, &code);
1279 		if (ret) {
1280 			trace_probe_log_err(ctx->offset + t - arg, BAD_BITFIELD);
1281 			goto fail;
1282 		}
1283 	} else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1284 		   ctx->last_type) {
1285 		ret = parse_btf_bitfield(&code, ctx);
1286 		if (ret)
1287 			goto fail;
1288 	}
1289 	ret = -EINVAL;
1290 	/* Loop(Array) operation */
1291 	if (parg->count) {
1292 		if (scode->op != FETCH_OP_ST_MEM &&
1293 		    scode->op != FETCH_OP_ST_STRING &&
1294 		    scode->op != FETCH_OP_ST_USTRING) {
1295 			trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
1296 					    BAD_STRING);
1297 			goto fail;
1298 		}
1299 		code++;
1300 		if (code->op != FETCH_OP_NOP) {
1301 			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1302 			goto fail;
1303 		}
1304 		code->op = FETCH_OP_LP_ARRAY;
1305 		code->param = parg->count;
1306 	}
1307 	code++;
1308 	code->op = FETCH_OP_END;
1309 
1310 	ret = 0;
1311 	/* Shrink down the code buffer */
1312 	parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
1313 	if (!parg->code)
1314 		ret = -ENOMEM;
1315 	else
1316 		memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1317 
1318 fail:
1319 	if (ret) {
1320 		for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1321 			if (code->op == FETCH_NOP_SYMBOL ||
1322 			    code->op == FETCH_OP_DATA)
1323 				kfree(code->data);
1324 	}
1325 	kfree(tmp);
1326 out:
1327 	kfree(arg);
1328 
1329 	return ret;
1330 }
1331 
1332 /* 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)1333 static int traceprobe_conflict_field_name(const char *name,
1334 					  struct probe_arg *args, int narg)
1335 {
1336 	int i;
1337 
1338 	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1339 		if (strcmp(reserved_field_names[i], name) == 0)
1340 			return 1;
1341 
1342 	for (i = 0; i < narg; i++)
1343 		if (strcmp(args[i].name, name) == 0)
1344 			return 1;
1345 
1346 	return 0;
1347 }
1348 
generate_probe_arg_name(const char * arg,int idx)1349 static char *generate_probe_arg_name(const char *arg, int idx)
1350 {
1351 	char *name = NULL;
1352 	const char *end;
1353 
1354 	/*
1355 	 * If argument name is omitted, try arg as a name (BTF variable)
1356 	 * or "argN".
1357 	 */
1358 	if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1359 		end = strchr(arg, ':');
1360 		if (!end)
1361 			end = arg + strlen(arg);
1362 
1363 		name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1364 		if (!name || !is_good_name(name)) {
1365 			kfree(name);
1366 			name = NULL;
1367 		}
1368 	}
1369 
1370 	if (!name)
1371 		name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1372 
1373 	return name;
1374 }
1375 
traceprobe_parse_probe_arg(struct trace_probe * tp,int i,const char * arg,struct traceprobe_parse_context * ctx)1376 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1377 			       struct traceprobe_parse_context *ctx)
1378 {
1379 	struct probe_arg *parg = &tp->args[i];
1380 	const char *body;
1381 
1382 	/* Increment count for freeing args in error case */
1383 	tp->nr_args++;
1384 
1385 	body = strchr(arg, '=');
1386 	if (body) {
1387 		if (body - arg > MAX_ARG_NAME_LEN) {
1388 			trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1389 			return -EINVAL;
1390 		} else if (body == arg) {
1391 			trace_probe_log_err(0, NO_ARG_NAME);
1392 			return -EINVAL;
1393 		}
1394 		parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1395 		body++;
1396 	} else {
1397 		parg->name = generate_probe_arg_name(arg, i);
1398 		body = arg;
1399 	}
1400 	if (!parg->name)
1401 		return -ENOMEM;
1402 
1403 	if (!is_good_name(parg->name)) {
1404 		trace_probe_log_err(0, BAD_ARG_NAME);
1405 		return -EINVAL;
1406 	}
1407 	if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1408 		trace_probe_log_err(0, USED_ARG_NAME);
1409 		return -EINVAL;
1410 	}
1411 	ctx->offset = body - arg;
1412 	/* Parse fetch argument */
1413 	return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1414 }
1415 
traceprobe_free_probe_arg(struct probe_arg * arg)1416 void traceprobe_free_probe_arg(struct probe_arg *arg)
1417 {
1418 	struct fetch_insn *code = arg->code;
1419 
1420 	while (code && code->op != FETCH_OP_END) {
1421 		if (code->op == FETCH_NOP_SYMBOL ||
1422 		    code->op == FETCH_OP_DATA)
1423 			kfree(code->data);
1424 		code++;
1425 	}
1426 	kfree(arg->code);
1427 	kfree(arg->name);
1428 	kfree(arg->comm);
1429 	kfree(arg->fmt);
1430 }
1431 
argv_has_var_arg(int argc,const char * argv[],int * args_idx,struct traceprobe_parse_context * ctx)1432 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1433 			    struct traceprobe_parse_context *ctx)
1434 {
1435 	int i, found = 0;
1436 
1437 	for (i = 0; i < argc; i++)
1438 		if (str_has_prefix(argv[i], "$arg")) {
1439 			trace_probe_log_set_index(i + 2);
1440 
1441 			if (!tparg_is_function_entry(ctx->flags)) {
1442 				trace_probe_log_err(0, NOFENTRY_ARGS);
1443 				return -EINVAL;
1444 			}
1445 
1446 			if (isdigit(argv[i][4])) {
1447 				found = 1;
1448 				continue;
1449 			}
1450 
1451 			if (argv[i][4] != '*') {
1452 				trace_probe_log_err(0, BAD_VAR);
1453 				return -EINVAL;
1454 			}
1455 
1456 			if (*args_idx >= 0 && *args_idx < argc) {
1457 				trace_probe_log_err(0, DOUBLE_ARGS);
1458 				return -EINVAL;
1459 			}
1460 			found = 1;
1461 			*args_idx = i;
1462 		}
1463 
1464 	return found;
1465 }
1466 
sprint_nth_btf_arg(int idx,const char * type,char * buf,int bufsize,struct traceprobe_parse_context * ctx)1467 static int sprint_nth_btf_arg(int idx, const char *type,
1468 			      char *buf, int bufsize,
1469 			      struct traceprobe_parse_context *ctx)
1470 {
1471 	const char *name;
1472 	int ret;
1473 
1474 	if (idx >= ctx->nr_params) {
1475 		trace_probe_log_err(0, NO_BTFARG);
1476 		return -ENOENT;
1477 	}
1478 	name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
1479 	if (!name) {
1480 		trace_probe_log_err(0, NO_BTF_ENTRY);
1481 		return -ENOENT;
1482 	}
1483 	ret = snprintf(buf, bufsize, "%s%s", name, type);
1484 	if (ret >= bufsize) {
1485 		trace_probe_log_err(0, ARGS_2LONG);
1486 		return -E2BIG;
1487 	}
1488 	return ret;
1489 }
1490 
1491 /* Return new_argv which must be freed after use */
traceprobe_expand_meta_args(int argc,const char * argv[],int * new_argc,char * buf,int bufsize,struct traceprobe_parse_context * ctx)1492 const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1493 					 int *new_argc, char *buf, int bufsize,
1494 					 struct traceprobe_parse_context *ctx)
1495 {
1496 	const struct btf_param *params = NULL;
1497 	int i, j, n, used, ret, args_idx = -1;
1498 	const char **new_argv = NULL;
1499 
1500 	ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1501 	if (ret < 0)
1502 		return ERR_PTR(ret);
1503 
1504 	if (!ret) {
1505 		*new_argc = argc;
1506 		return NULL;
1507 	}
1508 
1509 	ret = query_btf_context(ctx);
1510 	if (ret < 0 || ctx->nr_params == 0) {
1511 		if (args_idx != -1) {
1512 			/* $arg* requires BTF info */
1513 			trace_probe_log_err(0, NOSUP_BTFARG);
1514 			return (const char **)params;
1515 		}
1516 		*new_argc = argc;
1517 		return NULL;
1518 	}
1519 
1520 	if (args_idx >= 0)
1521 		*new_argc = argc + ctx->nr_params - 1;
1522 	else
1523 		*new_argc = argc;
1524 
1525 	new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1526 	if (!new_argv)
1527 		return ERR_PTR(-ENOMEM);
1528 
1529 	used = 0;
1530 	for (i = 0, j = 0; i < argc; i++) {
1531 		trace_probe_log_set_index(i + 2);
1532 		if (i == args_idx) {
1533 			for (n = 0; n < ctx->nr_params; n++) {
1534 				ret = sprint_nth_btf_arg(n, "", buf + used,
1535 							 bufsize - used, ctx);
1536 				if (ret < 0)
1537 					goto error;
1538 
1539 				new_argv[j++] = buf + used;
1540 				used += ret + 1;
1541 			}
1542 			continue;
1543 		}
1544 
1545 		if (str_has_prefix(argv[i], "$arg")) {
1546 			char *type = NULL;
1547 
1548 			n = simple_strtoul(argv[i] + 4, &type, 10);
1549 			if (type && !(*type == ':' || *type == '\0')) {
1550 				trace_probe_log_err(0, BAD_VAR);
1551 				ret = -ENOENT;
1552 				goto error;
1553 			}
1554 			/* Note: $argN starts from $arg1 */
1555 			ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1556 						 bufsize - used, ctx);
1557 			if (ret < 0)
1558 				goto error;
1559 			new_argv[j++] = buf + used;
1560 			used += ret + 1;
1561 		} else
1562 			new_argv[j++] = argv[i];
1563 	}
1564 
1565 	return new_argv;
1566 
1567 error:
1568 	kfree(new_argv);
1569 	return ERR_PTR(ret);
1570 }
1571 
traceprobe_finish_parse(struct traceprobe_parse_context * ctx)1572 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
1573 {
1574 	clear_btf_context(ctx);
1575 }
1576 
traceprobe_update_arg(struct probe_arg * arg)1577 int traceprobe_update_arg(struct probe_arg *arg)
1578 {
1579 	struct fetch_insn *code = arg->code;
1580 	long offset;
1581 	char *tmp;
1582 	char c;
1583 	int ret = 0;
1584 
1585 	while (code && code->op != FETCH_OP_END) {
1586 		if (code->op == FETCH_NOP_SYMBOL) {
1587 			if (code[1].op != FETCH_OP_IMM)
1588 				return -EINVAL;
1589 
1590 			tmp = strpbrk(code->data, "+-");
1591 			if (tmp)
1592 				c = *tmp;
1593 			ret = traceprobe_split_symbol_offset(code->data,
1594 							     &offset);
1595 			if (ret)
1596 				return ret;
1597 
1598 			code[1].immediate =
1599 				(unsigned long)kallsyms_lookup_name(code->data);
1600 			if (tmp)
1601 				*tmp = c;
1602 			if (!code[1].immediate)
1603 				return -ENOENT;
1604 			code[1].immediate += offset;
1605 		}
1606 		code++;
1607 	}
1608 	return 0;
1609 }
1610 
1611 /* When len=0, we just calculate the needed length */
1612 #define LEN_OR_ZERO (len ? len - pos : 0)
__set_print_fmt(struct trace_probe * tp,char * buf,int len,enum probe_print_type ptype)1613 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
1614 			   enum probe_print_type ptype)
1615 {
1616 	struct probe_arg *parg;
1617 	int i, j;
1618 	int pos = 0;
1619 	const char *fmt, *arg;
1620 
1621 	switch (ptype) {
1622 	case PROBE_PRINT_NORMAL:
1623 		fmt = "(%lx)";
1624 		arg = ", REC->" FIELD_STRING_IP;
1625 		break;
1626 	case PROBE_PRINT_RETURN:
1627 		fmt = "(%lx <- %lx)";
1628 		arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1629 		break;
1630 	case PROBE_PRINT_EVENT:
1631 		fmt = "";
1632 		arg = "";
1633 		break;
1634 	default:
1635 		WARN_ON_ONCE(1);
1636 		return 0;
1637 	}
1638 
1639 	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1640 
1641 	for (i = 0; i < tp->nr_args; i++) {
1642 		parg = tp->args + i;
1643 		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
1644 		if (parg->count) {
1645 			pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
1646 					parg->type->fmt);
1647 			for (j = 1; j < parg->count; j++)
1648 				pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
1649 						parg->type->fmt);
1650 			pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
1651 		} else
1652 			pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
1653 					parg->type->fmt);
1654 	}
1655 
1656 	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
1657 
1658 	for (i = 0; i < tp->nr_args; i++) {
1659 		parg = tp->args + i;
1660 		if (parg->count) {
1661 			if (parg->type->is_string)
1662 				fmt = ", __get_str(%s[%d])";
1663 			else
1664 				fmt = ", REC->%s[%d]";
1665 			for (j = 0; j < parg->count; j++)
1666 				pos += snprintf(buf + pos, LEN_OR_ZERO,
1667 						fmt, parg->name, j);
1668 		} else {
1669 			if (parg->type->is_string)
1670 				fmt = ", __get_str(%s)";
1671 			else
1672 				fmt = ", REC->%s";
1673 			pos += snprintf(buf + pos, LEN_OR_ZERO,
1674 					fmt, parg->name);
1675 		}
1676 	}
1677 
1678 	/* return the length of print_fmt */
1679 	return pos;
1680 }
1681 #undef LEN_OR_ZERO
1682 
traceprobe_set_print_fmt(struct trace_probe * tp,enum probe_print_type ptype)1683 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
1684 {
1685 	struct trace_event_call *call = trace_probe_event_call(tp);
1686 	int len;
1687 	char *print_fmt;
1688 
1689 	/* First: called with 0 length to calculate the needed length */
1690 	len = __set_print_fmt(tp, NULL, 0, ptype);
1691 	print_fmt = kmalloc(len + 1, GFP_KERNEL);
1692 	if (!print_fmt)
1693 		return -ENOMEM;
1694 
1695 	/* Second: actually write the @print_fmt */
1696 	__set_print_fmt(tp, print_fmt, len + 1, ptype);
1697 	call->print_fmt = print_fmt;
1698 
1699 	return 0;
1700 }
1701 
traceprobe_define_arg_fields(struct trace_event_call * event_call,size_t offset,struct trace_probe * tp)1702 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
1703 				 size_t offset, struct trace_probe *tp)
1704 {
1705 	int ret, i;
1706 
1707 	/* Set argument names as fields */
1708 	for (i = 0; i < tp->nr_args; i++) {
1709 		struct probe_arg *parg = &tp->args[i];
1710 		const char *fmt = parg->type->fmttype;
1711 		int size = parg->type->size;
1712 
1713 		if (parg->fmt)
1714 			fmt = parg->fmt;
1715 		if (parg->count)
1716 			size *= parg->count;
1717 		ret = trace_define_field(event_call, fmt, parg->name,
1718 					 offset + parg->offset, size,
1719 					 parg->type->is_signed,
1720 					 FILTER_OTHER);
1721 		if (ret)
1722 			return ret;
1723 	}
1724 	return 0;
1725 }
1726 
trace_probe_event_free(struct trace_probe_event * tpe)1727 static void trace_probe_event_free(struct trace_probe_event *tpe)
1728 {
1729 	kfree(tpe->class.system);
1730 	kfree(tpe->call.name);
1731 	kfree(tpe->call.print_fmt);
1732 	kfree(tpe);
1733 }
1734 
trace_probe_append(struct trace_probe * tp,struct trace_probe * to)1735 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
1736 {
1737 	if (trace_probe_has_sibling(tp))
1738 		return -EBUSY;
1739 
1740 	list_del_init(&tp->list);
1741 	trace_probe_event_free(tp->event);
1742 
1743 	tp->event = to->event;
1744 	list_add_tail(&tp->list, trace_probe_probe_list(to));
1745 
1746 	return 0;
1747 }
1748 
trace_probe_unlink(struct trace_probe * tp)1749 void trace_probe_unlink(struct trace_probe *tp)
1750 {
1751 	list_del_init(&tp->list);
1752 	if (list_empty(trace_probe_probe_list(tp)))
1753 		trace_probe_event_free(tp->event);
1754 	tp->event = NULL;
1755 }
1756 
trace_probe_cleanup(struct trace_probe * tp)1757 void trace_probe_cleanup(struct trace_probe *tp)
1758 {
1759 	int i;
1760 
1761 	for (i = 0; i < tp->nr_args; i++)
1762 		traceprobe_free_probe_arg(&tp->args[i]);
1763 
1764 	if (tp->event)
1765 		trace_probe_unlink(tp);
1766 }
1767 
trace_probe_init(struct trace_probe * tp,const char * event,const char * group,bool alloc_filter)1768 int trace_probe_init(struct trace_probe *tp, const char *event,
1769 		     const char *group, bool alloc_filter)
1770 {
1771 	struct trace_event_call *call;
1772 	size_t size = sizeof(struct trace_probe_event);
1773 	int ret = 0;
1774 
1775 	if (!event || !group)
1776 		return -EINVAL;
1777 
1778 	if (alloc_filter)
1779 		size += sizeof(struct trace_uprobe_filter);
1780 
1781 	tp->event = kzalloc(size, GFP_KERNEL);
1782 	if (!tp->event)
1783 		return -ENOMEM;
1784 
1785 	INIT_LIST_HEAD(&tp->event->files);
1786 	INIT_LIST_HEAD(&tp->event->class.fields);
1787 	INIT_LIST_HEAD(&tp->event->probes);
1788 	INIT_LIST_HEAD(&tp->list);
1789 	list_add(&tp->list, &tp->event->probes);
1790 
1791 	call = trace_probe_event_call(tp);
1792 	call->class = &tp->event->class;
1793 	call->name = kstrdup(event, GFP_KERNEL);
1794 	if (!call->name) {
1795 		ret = -ENOMEM;
1796 		goto error;
1797 	}
1798 
1799 	tp->event->class.system = kstrdup(group, GFP_KERNEL);
1800 	if (!tp->event->class.system) {
1801 		ret = -ENOMEM;
1802 		goto error;
1803 	}
1804 
1805 	return 0;
1806 
1807 error:
1808 	trace_probe_cleanup(tp);
1809 	return ret;
1810 }
1811 
1812 static struct trace_event_call *
find_trace_event_call(const char * system,const char * event_name)1813 find_trace_event_call(const char *system, const char *event_name)
1814 {
1815 	struct trace_event_call *tp_event;
1816 	const char *name;
1817 
1818 	list_for_each_entry(tp_event, &ftrace_events, list) {
1819 		if (!tp_event->class->system ||
1820 		    strcmp(system, tp_event->class->system))
1821 			continue;
1822 		name = trace_event_name(tp_event);
1823 		if (!name || strcmp(event_name, name))
1824 			continue;
1825 		return tp_event;
1826 	}
1827 
1828 	return NULL;
1829 }
1830 
trace_probe_register_event_call(struct trace_probe * tp)1831 int trace_probe_register_event_call(struct trace_probe *tp)
1832 {
1833 	struct trace_event_call *call = trace_probe_event_call(tp);
1834 	int ret;
1835 
1836 	lockdep_assert_held(&event_mutex);
1837 
1838 	if (find_trace_event_call(trace_probe_group_name(tp),
1839 				  trace_probe_name(tp)))
1840 		return -EEXIST;
1841 
1842 	ret = register_trace_event(&call->event);
1843 	if (!ret)
1844 		return -ENODEV;
1845 
1846 	ret = trace_add_event_call(call);
1847 	if (ret)
1848 		unregister_trace_event(&call->event);
1849 
1850 	return ret;
1851 }
1852 
trace_probe_add_file(struct trace_probe * tp,struct trace_event_file * file)1853 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
1854 {
1855 	struct event_file_link *link;
1856 
1857 	link = kmalloc(sizeof(*link), GFP_KERNEL);
1858 	if (!link)
1859 		return -ENOMEM;
1860 
1861 	link->file = file;
1862 	INIT_LIST_HEAD(&link->list);
1863 	list_add_tail_rcu(&link->list, &tp->event->files);
1864 	trace_probe_set_flag(tp, TP_FLAG_TRACE);
1865 	return 0;
1866 }
1867 
trace_probe_get_file_link(struct trace_probe * tp,struct trace_event_file * file)1868 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
1869 						  struct trace_event_file *file)
1870 {
1871 	struct event_file_link *link;
1872 
1873 	trace_probe_for_each_link(link, tp) {
1874 		if (link->file == file)
1875 			return link;
1876 	}
1877 
1878 	return NULL;
1879 }
1880 
trace_probe_remove_file(struct trace_probe * tp,struct trace_event_file * file)1881 int trace_probe_remove_file(struct trace_probe *tp,
1882 			    struct trace_event_file *file)
1883 {
1884 	struct event_file_link *link;
1885 
1886 	link = trace_probe_get_file_link(tp, file);
1887 	if (!link)
1888 		return -ENOENT;
1889 
1890 	list_del_rcu(&link->list);
1891 	kvfree_rcu_mightsleep(link);
1892 
1893 	if (list_empty(&tp->event->files))
1894 		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
1895 
1896 	return 0;
1897 }
1898 
1899 /*
1900  * Return the smallest index of different type argument (start from 1).
1901  * If all argument types and name are same, return 0.
1902  */
trace_probe_compare_arg_type(struct trace_probe * a,struct trace_probe * b)1903 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
1904 {
1905 	int i;
1906 
1907 	/* In case of more arguments */
1908 	if (a->nr_args < b->nr_args)
1909 		return a->nr_args + 1;
1910 	if (a->nr_args > b->nr_args)
1911 		return b->nr_args + 1;
1912 
1913 	for (i = 0; i < a->nr_args; i++) {
1914 		if ((b->nr_args <= i) ||
1915 		    ((a->args[i].type != b->args[i].type) ||
1916 		     (a->args[i].count != b->args[i].count) ||
1917 		     strcmp(a->args[i].name, b->args[i].name)))
1918 			return i + 1;
1919 	}
1920 
1921 	return 0;
1922 }
1923 
trace_probe_match_command_args(struct trace_probe * tp,int argc,const char ** argv)1924 bool trace_probe_match_command_args(struct trace_probe *tp,
1925 				    int argc, const char **argv)
1926 {
1927 	char buf[MAX_ARGSTR_LEN + 1];
1928 	int i;
1929 
1930 	if (tp->nr_args < argc)
1931 		return false;
1932 
1933 	for (i = 0; i < argc; i++) {
1934 		snprintf(buf, sizeof(buf), "%s=%s",
1935 			 tp->args[i].name, tp->args[i].comm);
1936 		if (strcmp(buf, argv[i]))
1937 			return false;
1938 	}
1939 	return true;
1940 }
1941 
trace_probe_create(const char * raw_command,int (* createfn)(int,const char **))1942 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
1943 {
1944 	int argc = 0, ret = 0;
1945 	char **argv;
1946 
1947 	argv = argv_split(GFP_KERNEL, raw_command, &argc);
1948 	if (!argv)
1949 		return -ENOMEM;
1950 
1951 	if (argc)
1952 		ret = createfn(argc, (const char **)argv);
1953 
1954 	argv_free(argv);
1955 
1956 	return ret;
1957 }
1958 
trace_probe_print_args(struct trace_seq * s,struct probe_arg * args,int nr_args,u8 * data,void * field)1959 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
1960 		 u8 *data, void *field)
1961 {
1962 	void *p;
1963 	int i, j;
1964 
1965 	for (i = 0; i < nr_args; i++) {
1966 		struct probe_arg *a = args + i;
1967 
1968 		trace_seq_printf(s, " %s=", a->name);
1969 		if (likely(!a->count)) {
1970 			if (!a->type->print(s, data + a->offset, field))
1971 				return -ENOMEM;
1972 			continue;
1973 		}
1974 		trace_seq_putc(s, '{');
1975 		p = data + a->offset;
1976 		for (j = 0; j < a->count; j++) {
1977 			if (!a->type->print(s, p, field))
1978 				return -ENOMEM;
1979 			trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
1980 			p += a->type->size;
1981 		}
1982 	}
1983 	return 0;
1984 }
1985