1 // SPDX-License-Identifier: GPL-2.0
2 #include <dirent.h>
3 #include <errno.h>
4 #include <stdlib.h>
5 #include <stdio.h>
6 #include <string.h>
7 #include <linux/capability.h>
8 #include <linux/kernel.h>
9 #include <linux/mman.h>
10 #include <linux/string.h>
11 #include <linux/time64.h>
12 #include <sys/types.h>
13 #include <sys/stat.h>
14 #include <sys/param.h>
15 #include <fcntl.h>
16 #include <unistd.h>
17 #include <inttypes.h>
18 #include "annotate.h"
19 #include "build-id.h"
20 #include "cap.h"
21 #include "cpumap.h"
22 #include "dso.h"
23 #include "util.h" // lsdir()
24 #include "debug.h"
25 #include "event.h"
26 #include "machine.h"
27 #include "map.h"
28 #include "symbol.h"
29 #include "map_symbol.h"
30 #include "mem-events.h"
31 #include "mem-info.h"
32 #include "symsrc.h"
33 #include "strlist.h"
34 #include "intlist.h"
35 #include "namespaces.h"
36 #include "header.h"
37 #include "path.h"
38 #include <linux/ctype.h>
39 #include <linux/zalloc.h>
40 
41 #include <elf.h>
42 #include <limits.h>
43 #include <symbol/kallsyms.h>
44 #include <sys/utsname.h>
45 
46 static int dso__load_kernel_sym(struct dso *dso, struct map *map);
47 static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map);
48 static bool symbol__is_idle(const char *name);
49 
50 int vmlinux_path__nr_entries;
51 char **vmlinux_path;
52 
53 struct symbol_conf symbol_conf = {
54 	.nanosecs		= false,
55 	.use_modules		= true,
56 	.try_vmlinux_path	= true,
57 	.demangle		= true,
58 	.demangle_kernel	= false,
59 	.cumulate_callchain	= true,
60 	.time_quantum		= 100 * NSEC_PER_MSEC, /* 100ms */
61 	.show_hist_headers	= true,
62 	.symfs			= "",
63 	.event_group		= true,
64 	.inline_name		= true,
65 	.res_sample		= 0,
66 };
67 
68 struct map_list_node {
69 	struct list_head node;
70 	struct map *map;
71 };
72 
map_list_node__new(void)73 static struct map_list_node *map_list_node__new(void)
74 {
75 	return malloc(sizeof(struct map_list_node));
76 }
77 
78 static enum dso_binary_type binary_type_symtab[] = {
79 	DSO_BINARY_TYPE__KALLSYMS,
80 	DSO_BINARY_TYPE__GUEST_KALLSYMS,
81 	DSO_BINARY_TYPE__JAVA_JIT,
82 	DSO_BINARY_TYPE__DEBUGLINK,
83 	DSO_BINARY_TYPE__BUILD_ID_CACHE,
84 	DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO,
85 	DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
86 	DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
87 	DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
88 	DSO_BINARY_TYPE__GNU_DEBUGDATA,
89 	DSO_BINARY_TYPE__SYSTEM_PATH_DSO,
90 	DSO_BINARY_TYPE__GUEST_KMODULE,
91 	DSO_BINARY_TYPE__GUEST_KMODULE_COMP,
92 	DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE,
93 	DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP,
94 	DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
95 	DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO,
96 	DSO_BINARY_TYPE__NOT_FOUND,
97 };
98 
99 #define DSO_BINARY_TYPE__SYMTAB_CNT ARRAY_SIZE(binary_type_symtab)
100 
symbol_type__filter(char symbol_type)101 static bool symbol_type__filter(char symbol_type)
102 {
103 	symbol_type = toupper(symbol_type);
104 	return symbol_type == 'T' || symbol_type == 'W' || symbol_type == 'D' || symbol_type == 'B';
105 }
106 
prefix_underscores_count(const char * str)107 static int prefix_underscores_count(const char *str)
108 {
109 	const char *tail = str;
110 
111 	while (*tail == '_')
112 		tail++;
113 
114 	return tail - str;
115 }
116 
arch__normalize_symbol_name(const char * name)117 const char * __weak arch__normalize_symbol_name(const char *name)
118 {
119 	return name;
120 }
121 
arch__compare_symbol_names(const char * namea,const char * nameb)122 int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
123 {
124 	return strcmp(namea, nameb);
125 }
126 
arch__compare_symbol_names_n(const char * namea,const char * nameb,unsigned int n)127 int __weak arch__compare_symbol_names_n(const char *namea, const char *nameb,
128 					unsigned int n)
129 {
130 	return strncmp(namea, nameb, n);
131 }
132 
arch__choose_best_symbol(struct symbol * syma,struct symbol * symb __maybe_unused)133 int __weak arch__choose_best_symbol(struct symbol *syma,
134 				    struct symbol *symb __maybe_unused)
135 {
136 	/* Avoid "SyS" kernel syscall aliases */
137 	if (strlen(syma->name) >= 3 && !strncmp(syma->name, "SyS", 3))
138 		return SYMBOL_B;
139 	if (strlen(syma->name) >= 10 && !strncmp(syma->name, "compat_SyS", 10))
140 		return SYMBOL_B;
141 
142 	return SYMBOL_A;
143 }
144 
choose_best_symbol(struct symbol * syma,struct symbol * symb)145 static int choose_best_symbol(struct symbol *syma, struct symbol *symb)
146 {
147 	s64 a;
148 	s64 b;
149 	size_t na, nb;
150 
151 	/* Prefer a symbol with non zero length */
152 	a = syma->end - syma->start;
153 	b = symb->end - symb->start;
154 	if ((b == 0) && (a > 0))
155 		return SYMBOL_A;
156 	else if ((a == 0) && (b > 0))
157 		return SYMBOL_B;
158 
159 	if (syma->type != symb->type) {
160 		if (syma->type == STT_NOTYPE)
161 			return SYMBOL_B;
162 		if (symb->type == STT_NOTYPE)
163 			return SYMBOL_A;
164 	}
165 
166 	/* Prefer a non weak symbol over a weak one */
167 	a = syma->binding == STB_WEAK;
168 	b = symb->binding == STB_WEAK;
169 	if (b && !a)
170 		return SYMBOL_A;
171 	if (a && !b)
172 		return SYMBOL_B;
173 
174 	/* Prefer a global symbol over a non global one */
175 	a = syma->binding == STB_GLOBAL;
176 	b = symb->binding == STB_GLOBAL;
177 	if (a && !b)
178 		return SYMBOL_A;
179 	if (b && !a)
180 		return SYMBOL_B;
181 
182 	/* Prefer a symbol with less underscores */
183 	a = prefix_underscores_count(syma->name);
184 	b = prefix_underscores_count(symb->name);
185 	if (b > a)
186 		return SYMBOL_A;
187 	else if (a > b)
188 		return SYMBOL_B;
189 
190 	/* Choose the symbol with the longest name */
191 	na = strlen(syma->name);
192 	nb = strlen(symb->name);
193 	if (na > nb)
194 		return SYMBOL_A;
195 	else if (na < nb)
196 		return SYMBOL_B;
197 
198 	return arch__choose_best_symbol(syma, symb);
199 }
200 
symbols__fixup_duplicate(struct rb_root_cached * symbols)201 void symbols__fixup_duplicate(struct rb_root_cached *symbols)
202 {
203 	struct rb_node *nd;
204 	struct symbol *curr, *next;
205 
206 	if (symbol_conf.allow_aliases)
207 		return;
208 
209 	nd = rb_first_cached(symbols);
210 
211 	while (nd) {
212 		curr = rb_entry(nd, struct symbol, rb_node);
213 again:
214 		nd = rb_next(&curr->rb_node);
215 		if (!nd)
216 			break;
217 
218 		next = rb_entry(nd, struct symbol, rb_node);
219 		if (curr->start != next->start)
220 			continue;
221 
222 		if (choose_best_symbol(curr, next) == SYMBOL_A) {
223 			if (next->type == STT_GNU_IFUNC)
224 				curr->ifunc_alias = true;
225 			rb_erase_cached(&next->rb_node, symbols);
226 			symbol__delete(next);
227 			goto again;
228 		} else {
229 			if (curr->type == STT_GNU_IFUNC)
230 				next->ifunc_alias = true;
231 			nd = rb_next(&curr->rb_node);
232 			rb_erase_cached(&curr->rb_node, symbols);
233 			symbol__delete(curr);
234 		}
235 	}
236 }
237 
238 /* Update zero-sized symbols using the address of the next symbol */
symbols__fixup_end(struct rb_root_cached * symbols,bool is_kallsyms)239 void symbols__fixup_end(struct rb_root_cached *symbols, bool is_kallsyms)
240 {
241 	struct rb_node *nd, *prevnd = rb_first_cached(symbols);
242 	struct symbol *curr, *prev;
243 
244 	if (prevnd == NULL)
245 		return;
246 
247 	curr = rb_entry(prevnd, struct symbol, rb_node);
248 
249 	for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
250 		prev = curr;
251 		curr = rb_entry(nd, struct symbol, rb_node);
252 
253 		/*
254 		 * On some architecture kernel text segment start is located at
255 		 * some low memory address, while modules are located at high
256 		 * memory addresses (or vice versa).  The gap between end of
257 		 * kernel text segment and beginning of first module's text
258 		 * segment is very big.  Therefore do not fill this gap and do
259 		 * not assign it to the kernel dso map (kallsyms).
260 		 *
261 		 * Also BPF code can be allocated separately from text segments
262 		 * and modules.  So the last entry in a module should not fill
263 		 * the gap too.
264 		 *
265 		 * In kallsyms, it determines module symbols using '[' character
266 		 * like in:
267 		 *   ffffffffc1937000 T hdmi_driver_init  [snd_hda_codec_hdmi]
268 		 */
269 		if (prev->end == prev->start) {
270 			const char *prev_mod;
271 			const char *curr_mod;
272 
273 			if (!is_kallsyms) {
274 				prev->end = curr->start;
275 				continue;
276 			}
277 
278 			prev_mod = strchr(prev->name, '[');
279 			curr_mod = strchr(curr->name, '[');
280 
281 			/* Last kernel/module symbol mapped to end of page */
282 			if (!prev_mod != !curr_mod)
283 				prev->end = roundup(prev->end + 4096, 4096);
284 			/* Last symbol in the previous module */
285 			else if (prev_mod && strcmp(prev_mod, curr_mod))
286 				prev->end = roundup(prev->end + 4096, 4096);
287 			else
288 				prev->end = curr->start;
289 
290 			pr_debug4("%s sym:%s end:%#" PRIx64 "\n",
291 				  __func__, prev->name, prev->end);
292 		}
293 	}
294 
295 	/* Last entry */
296 	if (curr->end == curr->start)
297 		curr->end = roundup(curr->start, 4096) + 4096;
298 }
299 
symbol__new(u64 start,u64 len,u8 binding,u8 type,const char * name)300 struct symbol *symbol__new(u64 start, u64 len, u8 binding, u8 type, const char *name)
301 {
302 	size_t namelen = strlen(name) + 1;
303 	struct symbol *sym = calloc(1, (symbol_conf.priv_size +
304 					sizeof(*sym) + namelen));
305 	if (sym == NULL)
306 		return NULL;
307 
308 	if (symbol_conf.priv_size) {
309 		if (symbol_conf.init_annotation) {
310 			struct annotation *notes = (void *)sym;
311 			annotation__init(notes);
312 		}
313 		sym = ((void *)sym) + symbol_conf.priv_size;
314 	}
315 
316 	sym->start   = start;
317 	sym->end     = len ? start + len : start;
318 	sym->type    = type;
319 	sym->binding = binding;
320 	sym->namelen = namelen - 1;
321 
322 	pr_debug4("%s: %s %#" PRIx64 "-%#" PRIx64 "\n",
323 		  __func__, name, start, sym->end);
324 	memcpy(sym->name, name, namelen);
325 
326 	return sym;
327 }
328 
symbol__delete(struct symbol * sym)329 void symbol__delete(struct symbol *sym)
330 {
331 	if (symbol_conf.priv_size) {
332 		if (symbol_conf.init_annotation) {
333 			struct annotation *notes = symbol__annotation(sym);
334 
335 			annotation__exit(notes);
336 		}
337 	}
338 	free(((void *)sym) - symbol_conf.priv_size);
339 }
340 
symbols__delete(struct rb_root_cached * symbols)341 void symbols__delete(struct rb_root_cached *symbols)
342 {
343 	struct symbol *pos;
344 	struct rb_node *next = rb_first_cached(symbols);
345 
346 	while (next) {
347 		pos = rb_entry(next, struct symbol, rb_node);
348 		next = rb_next(&pos->rb_node);
349 		rb_erase_cached(&pos->rb_node, symbols);
350 		symbol__delete(pos);
351 	}
352 }
353 
__symbols__insert(struct rb_root_cached * symbols,struct symbol * sym,bool kernel)354 void __symbols__insert(struct rb_root_cached *symbols,
355 		       struct symbol *sym, bool kernel)
356 {
357 	struct rb_node **p = &symbols->rb_root.rb_node;
358 	struct rb_node *parent = NULL;
359 	const u64 ip = sym->start;
360 	struct symbol *s;
361 	bool leftmost = true;
362 
363 	if (kernel) {
364 		const char *name = sym->name;
365 		/*
366 		 * ppc64 uses function descriptors and appends a '.' to the
367 		 * start of every instruction address. Remove it.
368 		 */
369 		if (name[0] == '.')
370 			name++;
371 		sym->idle = symbol__is_idle(name);
372 	}
373 
374 	while (*p != NULL) {
375 		parent = *p;
376 		s = rb_entry(parent, struct symbol, rb_node);
377 		if (ip < s->start)
378 			p = &(*p)->rb_left;
379 		else {
380 			p = &(*p)->rb_right;
381 			leftmost = false;
382 		}
383 	}
384 	rb_link_node(&sym->rb_node, parent, p);
385 	rb_insert_color_cached(&sym->rb_node, symbols, leftmost);
386 }
387 
symbols__insert(struct rb_root_cached * symbols,struct symbol * sym)388 void symbols__insert(struct rb_root_cached *symbols, struct symbol *sym)
389 {
390 	__symbols__insert(symbols, sym, false);
391 }
392 
symbols__find(struct rb_root_cached * symbols,u64 ip)393 static struct symbol *symbols__find(struct rb_root_cached *symbols, u64 ip)
394 {
395 	struct rb_node *n;
396 
397 	if (symbols == NULL)
398 		return NULL;
399 
400 	n = symbols->rb_root.rb_node;
401 
402 	while (n) {
403 		struct symbol *s = rb_entry(n, struct symbol, rb_node);
404 
405 		if (ip < s->start)
406 			n = n->rb_left;
407 		else if (ip > s->end || (ip == s->end && ip != s->start))
408 			n = n->rb_right;
409 		else
410 			return s;
411 	}
412 
413 	return NULL;
414 }
415 
symbols__first(struct rb_root_cached * symbols)416 static struct symbol *symbols__first(struct rb_root_cached *symbols)
417 {
418 	struct rb_node *n = rb_first_cached(symbols);
419 
420 	if (n)
421 		return rb_entry(n, struct symbol, rb_node);
422 
423 	return NULL;
424 }
425 
symbols__last(struct rb_root_cached * symbols)426 static struct symbol *symbols__last(struct rb_root_cached *symbols)
427 {
428 	struct rb_node *n = rb_last(&symbols->rb_root);
429 
430 	if (n)
431 		return rb_entry(n, struct symbol, rb_node);
432 
433 	return NULL;
434 }
435 
symbols__next(struct symbol * sym)436 static struct symbol *symbols__next(struct symbol *sym)
437 {
438 	struct rb_node *n = rb_next(&sym->rb_node);
439 
440 	if (n)
441 		return rb_entry(n, struct symbol, rb_node);
442 
443 	return NULL;
444 }
445 
symbols__sort_name_cmp(const void * vlhs,const void * vrhs)446 static int symbols__sort_name_cmp(const void *vlhs, const void *vrhs)
447 {
448 	const struct symbol *lhs = *((const struct symbol **)vlhs);
449 	const struct symbol *rhs = *((const struct symbol **)vrhs);
450 
451 	return strcmp(lhs->name, rhs->name);
452 }
453 
symbols__sort_by_name(struct rb_root_cached * source,size_t * len)454 static struct symbol **symbols__sort_by_name(struct rb_root_cached *source, size_t *len)
455 {
456 	struct rb_node *nd;
457 	struct symbol **result;
458 	size_t i = 0, size = 0;
459 
460 	for (nd = rb_first_cached(source); nd; nd = rb_next(nd))
461 		size++;
462 
463 	result = malloc(sizeof(*result) * size);
464 	if (!result)
465 		return NULL;
466 
467 	for (nd = rb_first_cached(source); nd; nd = rb_next(nd)) {
468 		struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
469 
470 		result[i++] = pos;
471 	}
472 	qsort(result, size, sizeof(*result), symbols__sort_name_cmp);
473 	*len = size;
474 	return result;
475 }
476 
symbol__match_symbol_name(const char * name,const char * str,enum symbol_tag_include includes)477 int symbol__match_symbol_name(const char *name, const char *str,
478 			      enum symbol_tag_include includes)
479 {
480 	const char *versioning;
481 
482 	if (includes == SYMBOL_TAG_INCLUDE__DEFAULT_ONLY &&
483 	    (versioning = strstr(name, "@@"))) {
484 		int len = strlen(str);
485 
486 		if (len < versioning - name)
487 			len = versioning - name;
488 
489 		return arch__compare_symbol_names_n(name, str, len);
490 	} else
491 		return arch__compare_symbol_names(name, str);
492 }
493 
symbols__find_by_name(struct symbol * symbols[],size_t symbols_len,const char * name,enum symbol_tag_include includes,size_t * found_idx)494 static struct symbol *symbols__find_by_name(struct symbol *symbols[],
495 					    size_t symbols_len,
496 					    const char *name,
497 					    enum symbol_tag_include includes,
498 					    size_t *found_idx)
499 {
500 	size_t i, lower = 0, upper = symbols_len;
501 	struct symbol *s = NULL;
502 
503 	if (found_idx)
504 		*found_idx = SIZE_MAX;
505 
506 	if (!symbols_len)
507 		return NULL;
508 
509 	while (lower < upper) {
510 		int cmp;
511 
512 		i = (lower + upper) / 2;
513 		cmp = symbol__match_symbol_name(symbols[i]->name, name, includes);
514 
515 		if (cmp > 0)
516 			upper = i;
517 		else if (cmp < 0)
518 			lower = i + 1;
519 		else {
520 			if (found_idx)
521 				*found_idx = i;
522 			s = symbols[i];
523 			break;
524 		}
525 	}
526 	if (s && includes != SYMBOL_TAG_INCLUDE__DEFAULT_ONLY) {
527 		/* return first symbol that has same name (if any) */
528 		for (; i > 0; i--) {
529 			struct symbol *tmp = symbols[i - 1];
530 
531 			if (!arch__compare_symbol_names(tmp->name, s->name)) {
532 				if (found_idx)
533 					*found_idx = i - 1;
534 				s = tmp;
535 			} else
536 				break;
537 		}
538 	}
539 	assert(!found_idx || !s || s == symbols[*found_idx]);
540 	return s;
541 }
542 
dso__reset_find_symbol_cache(struct dso * dso)543 void dso__reset_find_symbol_cache(struct dso *dso)
544 {
545 	dso__set_last_find_result_addr(dso, 0);
546 	dso__set_last_find_result_symbol(dso, NULL);
547 }
548 
dso__insert_symbol(struct dso * dso,struct symbol * sym)549 void dso__insert_symbol(struct dso *dso, struct symbol *sym)
550 {
551 	__symbols__insert(dso__symbols(dso), sym, dso__kernel(dso));
552 
553 	/* update the symbol cache if necessary */
554 	if (dso__last_find_result_addr(dso) >= sym->start &&
555 	    (dso__last_find_result_addr(dso) < sym->end ||
556 	    sym->start == sym->end)) {
557 		dso__set_last_find_result_symbol(dso, sym);
558 	}
559 }
560 
dso__delete_symbol(struct dso * dso,struct symbol * sym)561 void dso__delete_symbol(struct dso *dso, struct symbol *sym)
562 {
563 	rb_erase_cached(&sym->rb_node, dso__symbols(dso));
564 	symbol__delete(sym);
565 	dso__reset_find_symbol_cache(dso);
566 }
567 
dso__find_symbol(struct dso * dso,u64 addr)568 struct symbol *dso__find_symbol(struct dso *dso, u64 addr)
569 {
570 	if (dso__last_find_result_addr(dso) != addr || dso__last_find_result_symbol(dso) == NULL) {
571 		dso__set_last_find_result_addr(dso, addr);
572 		dso__set_last_find_result_symbol(dso, symbols__find(dso__symbols(dso), addr));
573 	}
574 
575 	return dso__last_find_result_symbol(dso);
576 }
577 
dso__find_symbol_nocache(struct dso * dso,u64 addr)578 struct symbol *dso__find_symbol_nocache(struct dso *dso, u64 addr)
579 {
580 	return symbols__find(dso__symbols(dso), addr);
581 }
582 
dso__first_symbol(struct dso * dso)583 struct symbol *dso__first_symbol(struct dso *dso)
584 {
585 	return symbols__first(dso__symbols(dso));
586 }
587 
dso__last_symbol(struct dso * dso)588 struct symbol *dso__last_symbol(struct dso *dso)
589 {
590 	return symbols__last(dso__symbols(dso));
591 }
592 
dso__next_symbol(struct symbol * sym)593 struct symbol *dso__next_symbol(struct symbol *sym)
594 {
595 	return symbols__next(sym);
596 }
597 
dso__next_symbol_by_name(struct dso * dso,size_t * idx)598 struct symbol *dso__next_symbol_by_name(struct dso *dso, size_t *idx)
599 {
600 	if (*idx + 1 >= dso__symbol_names_len(dso))
601 		return NULL;
602 
603 	++*idx;
604 	return dso__symbol_names(dso)[*idx];
605 }
606 
607  /*
608   * Returns first symbol that matched with @name.
609   */
dso__find_symbol_by_name(struct dso * dso,const char * name,size_t * idx)610 struct symbol *dso__find_symbol_by_name(struct dso *dso, const char *name, size_t *idx)
611 {
612 	struct symbol *s = symbols__find_by_name(dso__symbol_names(dso),
613 						 dso__symbol_names_len(dso),
614 						 name, SYMBOL_TAG_INCLUDE__NONE, idx);
615 	if (!s) {
616 		s = symbols__find_by_name(dso__symbol_names(dso), dso__symbol_names_len(dso),
617 					  name, SYMBOL_TAG_INCLUDE__DEFAULT_ONLY, idx);
618 	}
619 	return s;
620 }
621 
dso__sort_by_name(struct dso * dso)622 void dso__sort_by_name(struct dso *dso)
623 {
624 	mutex_lock(dso__lock(dso));
625 	if (!dso__sorted_by_name(dso)) {
626 		size_t len;
627 
628 		dso__set_symbol_names(dso, symbols__sort_by_name(dso__symbols(dso), &len));
629 		if (dso__symbol_names(dso)) {
630 			dso__set_symbol_names_len(dso, len);
631 			dso__set_sorted_by_name(dso);
632 		}
633 	}
634 	mutex_unlock(dso__lock(dso));
635 }
636 
637 /*
638  * While we find nice hex chars, build a long_val.
639  * Return number of chars processed.
640  */
hex2u64(const char * ptr,u64 * long_val)641 static int hex2u64(const char *ptr, u64 *long_val)
642 {
643 	char *p;
644 
645 	*long_val = strtoull(ptr, &p, 16);
646 
647 	return p - ptr;
648 }
649 
650 
modules__parse(const char * filename,void * arg,int (* process_module)(void * arg,const char * name,u64 start,u64 size))651 int modules__parse(const char *filename, void *arg,
652 		   int (*process_module)(void *arg, const char *name,
653 					 u64 start, u64 size))
654 {
655 	char *line = NULL;
656 	size_t n;
657 	FILE *file;
658 	int err = 0;
659 
660 	file = fopen(filename, "r");
661 	if (file == NULL)
662 		return -1;
663 
664 	while (1) {
665 		char name[PATH_MAX];
666 		u64 start, size;
667 		char *sep, *endptr;
668 		ssize_t line_len;
669 
670 		line_len = getline(&line, &n, file);
671 		if (line_len < 0) {
672 			if (feof(file))
673 				break;
674 			err = -1;
675 			goto out;
676 		}
677 
678 		if (!line) {
679 			err = -1;
680 			goto out;
681 		}
682 
683 		line[--line_len] = '\0'; /* \n */
684 
685 		sep = strrchr(line, 'x');
686 		if (sep == NULL)
687 			continue;
688 
689 		hex2u64(sep + 1, &start);
690 
691 		sep = strchr(line, ' ');
692 		if (sep == NULL)
693 			continue;
694 
695 		*sep = '\0';
696 
697 		scnprintf(name, sizeof(name), "[%s]", line);
698 
699 		size = strtoul(sep + 1, &endptr, 0);
700 		if (*endptr != ' ' && *endptr != '\t')
701 			continue;
702 
703 		err = process_module(arg, name, start, size);
704 		if (err)
705 			break;
706 	}
707 out:
708 	free(line);
709 	fclose(file);
710 	return err;
711 }
712 
713 /*
714  * These are symbols in the kernel image, so make sure that
715  * sym is from a kernel DSO.
716  */
symbol__is_idle(const char * name)717 static bool symbol__is_idle(const char *name)
718 {
719 	const char * const idle_symbols[] = {
720 		"acpi_idle_do_entry",
721 		"acpi_processor_ffh_cstate_enter",
722 		"arch_cpu_idle",
723 		"cpu_idle",
724 		"cpu_startup_entry",
725 		"idle_cpu",
726 		"intel_idle",
727 		"intel_idle_ibrs",
728 		"default_idle",
729 		"native_safe_halt",
730 		"enter_idle",
731 		"exit_idle",
732 		"mwait_idle",
733 		"mwait_idle_with_hints",
734 		"mwait_idle_with_hints.constprop.0",
735 		"poll_idle",
736 		"ppc64_runlatch_off",
737 		"pseries_dedicated_idle_sleep",
738 		"psw_idle",
739 		"psw_idle_exit",
740 		NULL
741 	};
742 	int i;
743 	static struct strlist *idle_symbols_list;
744 
745 	if (idle_symbols_list)
746 		return strlist__has_entry(idle_symbols_list, name);
747 
748 	idle_symbols_list = strlist__new(NULL, NULL);
749 
750 	for (i = 0; idle_symbols[i]; i++)
751 		strlist__add(idle_symbols_list, idle_symbols[i]);
752 
753 	return strlist__has_entry(idle_symbols_list, name);
754 }
755 
map__process_kallsym_symbol(void * arg,const char * name,char type,u64 start)756 static int map__process_kallsym_symbol(void *arg, const char *name,
757 				       char type, u64 start)
758 {
759 	struct symbol *sym;
760 	struct dso *dso = arg;
761 	struct rb_root_cached *root = dso__symbols(dso);
762 
763 	if (!symbol_type__filter(type))
764 		return 0;
765 
766 	/* Ignore local symbols for ARM modules */
767 	if (name[0] == '$')
768 		return 0;
769 
770 	/*
771 	 * module symbols are not sorted so we add all
772 	 * symbols, setting length to 0, and rely on
773 	 * symbols__fixup_end() to fix it up.
774 	 */
775 	sym = symbol__new(start, 0, kallsyms2elf_binding(type), kallsyms2elf_type(type), name);
776 	if (sym == NULL)
777 		return -ENOMEM;
778 	/*
779 	 * We will pass the symbols to the filter later, in
780 	 * map__split_kallsyms, when we have split the maps per module
781 	 */
782 	__symbols__insert(root, sym, !strchr(name, '['));
783 
784 	return 0;
785 }
786 
787 /*
788  * Loads the function entries in /proc/kallsyms into kernel_map->dso,
789  * so that we can in the next step set the symbol ->end address and then
790  * call kernel_maps__split_kallsyms.
791  */
dso__load_all_kallsyms(struct dso * dso,const char * filename)792 static int dso__load_all_kallsyms(struct dso *dso, const char *filename)
793 {
794 	return kallsyms__parse(filename, dso, map__process_kallsym_symbol);
795 }
796 
maps__split_kallsyms_for_kcore(struct maps * kmaps,struct dso * dso)797 static int maps__split_kallsyms_for_kcore(struct maps *kmaps, struct dso *dso)
798 {
799 	struct symbol *pos;
800 	int count = 0;
801 	struct rb_root_cached *root = dso__symbols(dso);
802 	struct rb_root_cached old_root = *root;
803 	struct rb_node *next = rb_first_cached(root);
804 
805 	if (!kmaps)
806 		return -1;
807 
808 	*root = RB_ROOT_CACHED;
809 
810 	while (next) {
811 		struct map *curr_map;
812 		struct dso *curr_map_dso;
813 		char *module;
814 
815 		pos = rb_entry(next, struct symbol, rb_node);
816 		next = rb_next(&pos->rb_node);
817 
818 		rb_erase_cached(&pos->rb_node, &old_root);
819 		RB_CLEAR_NODE(&pos->rb_node);
820 		module = strchr(pos->name, '\t');
821 		if (module)
822 			*module = '\0';
823 
824 		curr_map = maps__find(kmaps, pos->start);
825 
826 		if (!curr_map) {
827 			symbol__delete(pos);
828 			continue;
829 		}
830 		curr_map_dso = map__dso(curr_map);
831 		pos->start -= map__start(curr_map) - map__pgoff(curr_map);
832 		if (pos->end > map__end(curr_map))
833 			pos->end = map__end(curr_map);
834 		if (pos->end)
835 			pos->end -= map__start(curr_map) - map__pgoff(curr_map);
836 		symbols__insert(dso__symbols(curr_map_dso), pos);
837 		++count;
838 		map__put(curr_map);
839 	}
840 
841 	/* Symbols have been adjusted */
842 	dso__set_adjust_symbols(dso, true);
843 
844 	return count;
845 }
846 
847 /*
848  * Split the symbols into maps, making sure there are no overlaps, i.e. the
849  * kernel range is broken in several maps, named [kernel].N, as we don't have
850  * the original ELF section names vmlinux have.
851  */
maps__split_kallsyms(struct maps * kmaps,struct dso * dso,u64 delta,struct map * initial_map)852 static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
853 				struct map *initial_map)
854 {
855 	struct machine *machine;
856 	struct map *curr_map = map__get(initial_map);
857 	struct symbol *pos;
858 	int count = 0, moved = 0;
859 	struct rb_root_cached *root = dso__symbols(dso);
860 	struct rb_node *next = rb_first_cached(root);
861 	int kernel_range = 0;
862 	bool x86_64;
863 
864 	if (!kmaps)
865 		return -1;
866 
867 	machine = maps__machine(kmaps);
868 
869 	x86_64 = machine__is(machine, "x86_64");
870 
871 	while (next) {
872 		char *module;
873 
874 		pos = rb_entry(next, struct symbol, rb_node);
875 		next = rb_next(&pos->rb_node);
876 
877 		module = strchr(pos->name, '\t');
878 		if (module) {
879 			struct dso *curr_map_dso;
880 
881 			if (!symbol_conf.use_modules)
882 				goto discard_symbol;
883 
884 			*module++ = '\0';
885 			curr_map_dso = map__dso(curr_map);
886 			if (strcmp(dso__short_name(curr_map_dso), module)) {
887 				if (!RC_CHK_EQUAL(curr_map, initial_map) &&
888 				    dso__kernel(dso) == DSO_SPACE__KERNEL_GUEST &&
889 				    machine__is_default_guest(machine)) {
890 					/*
891 					 * We assume all symbols of a module are
892 					 * continuous in * kallsyms, so curr_map
893 					 * points to a module and all its
894 					 * symbols are in its kmap. Mark it as
895 					 * loaded.
896 					 */
897 					dso__set_loaded(curr_map_dso);
898 				}
899 
900 				map__zput(curr_map);
901 				curr_map = maps__find_by_name(kmaps, module);
902 				if (curr_map == NULL) {
903 					pr_debug("%s/proc/{kallsyms,modules} "
904 					         "inconsistency while looking "
905 						 "for \"%s\" module!\n",
906 						 machine->root_dir, module);
907 					curr_map = map__get(initial_map);
908 					goto discard_symbol;
909 				}
910 				curr_map_dso = map__dso(curr_map);
911 				if (dso__loaded(curr_map_dso) &&
912 				    !machine__is_default_guest(machine))
913 					goto discard_symbol;
914 			}
915 			/*
916 			 * So that we look just like we get from .ko files,
917 			 * i.e. not prelinked, relative to initial_map->start.
918 			 */
919 			pos->start = map__map_ip(curr_map, pos->start);
920 			pos->end   = map__map_ip(curr_map, pos->end);
921 		} else if (x86_64 && is_entry_trampoline(pos->name)) {
922 			/*
923 			 * These symbols are not needed anymore since the
924 			 * trampoline maps refer to the text section and it's
925 			 * symbols instead. Avoid having to deal with
926 			 * relocations, and the assumption that the first symbol
927 			 * is the start of kernel text, by simply removing the
928 			 * symbols at this point.
929 			 */
930 			goto discard_symbol;
931 		} else if (!RC_CHK_EQUAL(curr_map, initial_map)) {
932 			char dso_name[PATH_MAX];
933 			struct dso *ndso;
934 
935 			if (delta) {
936 				/* Kernel was relocated at boot time */
937 				pos->start -= delta;
938 				pos->end -= delta;
939 			}
940 
941 			if (count == 0) {
942 				map__zput(curr_map);
943 				curr_map = map__get(initial_map);
944 				goto add_symbol;
945 			}
946 
947 			if (dso__kernel(dso) == DSO_SPACE__KERNEL_GUEST)
948 				snprintf(dso_name, sizeof(dso_name),
949 					"[guest.kernel].%d",
950 					kernel_range++);
951 			else
952 				snprintf(dso_name, sizeof(dso_name),
953 					"[kernel].%d",
954 					kernel_range++);
955 
956 			ndso = dso__new(dso_name);
957 			map__zput(curr_map);
958 			if (ndso == NULL)
959 				return -1;
960 
961 			dso__set_kernel(ndso, dso__kernel(dso));
962 
963 			curr_map = map__new2(pos->start, ndso);
964 			if (curr_map == NULL) {
965 				dso__put(ndso);
966 				return -1;
967 			}
968 
969 			map__set_mapping_type(curr_map, MAPPING_TYPE__IDENTITY);
970 			if (maps__insert(kmaps, curr_map)) {
971 				map__zput(curr_map);
972 				dso__put(ndso);
973 				return -1;
974 			}
975 			++kernel_range;
976 		} else if (delta) {
977 			/* Kernel was relocated at boot time */
978 			pos->start -= delta;
979 			pos->end -= delta;
980 		}
981 add_symbol:
982 		if (!RC_CHK_EQUAL(curr_map, initial_map)) {
983 			struct dso *curr_map_dso = map__dso(curr_map);
984 
985 			rb_erase_cached(&pos->rb_node, root);
986 			symbols__insert(dso__symbols(curr_map_dso), pos);
987 			++moved;
988 		} else
989 			++count;
990 
991 		continue;
992 discard_symbol:
993 		rb_erase_cached(&pos->rb_node, root);
994 		symbol__delete(pos);
995 	}
996 
997 	if (!RC_CHK_EQUAL(curr_map, initial_map) &&
998 	    dso__kernel(dso) == DSO_SPACE__KERNEL_GUEST &&
999 	    machine__is_default_guest(maps__machine(kmaps))) {
1000 		dso__set_loaded(map__dso(curr_map));
1001 	}
1002 	map__put(curr_map);
1003 	return count + moved;
1004 }
1005 
symbol__restricted_filename(const char * filename,const char * restricted_filename)1006 bool symbol__restricted_filename(const char *filename,
1007 				 const char *restricted_filename)
1008 {
1009 	bool restricted = false;
1010 
1011 	if (symbol_conf.kptr_restrict) {
1012 		char *r = realpath(filename, NULL);
1013 
1014 		if (r != NULL) {
1015 			restricted = strcmp(r, restricted_filename) == 0;
1016 			free(r);
1017 			return restricted;
1018 		}
1019 	}
1020 
1021 	return restricted;
1022 }
1023 
1024 struct module_info {
1025 	struct rb_node rb_node;
1026 	char *name;
1027 	u64 start;
1028 };
1029 
add_module(struct module_info * mi,struct rb_root * modules)1030 static void add_module(struct module_info *mi, struct rb_root *modules)
1031 {
1032 	struct rb_node **p = &modules->rb_node;
1033 	struct rb_node *parent = NULL;
1034 	struct module_info *m;
1035 
1036 	while (*p != NULL) {
1037 		parent = *p;
1038 		m = rb_entry(parent, struct module_info, rb_node);
1039 		if (strcmp(mi->name, m->name) < 0)
1040 			p = &(*p)->rb_left;
1041 		else
1042 			p = &(*p)->rb_right;
1043 	}
1044 	rb_link_node(&mi->rb_node, parent, p);
1045 	rb_insert_color(&mi->rb_node, modules);
1046 }
1047 
delete_modules(struct rb_root * modules)1048 static void delete_modules(struct rb_root *modules)
1049 {
1050 	struct module_info *mi;
1051 	struct rb_node *next = rb_first(modules);
1052 
1053 	while (next) {
1054 		mi = rb_entry(next, struct module_info, rb_node);
1055 		next = rb_next(&mi->rb_node);
1056 		rb_erase(&mi->rb_node, modules);
1057 		zfree(&mi->name);
1058 		free(mi);
1059 	}
1060 }
1061 
find_module(const char * name,struct rb_root * modules)1062 static struct module_info *find_module(const char *name,
1063 				       struct rb_root *modules)
1064 {
1065 	struct rb_node *n = modules->rb_node;
1066 
1067 	while (n) {
1068 		struct module_info *m;
1069 		int cmp;
1070 
1071 		m = rb_entry(n, struct module_info, rb_node);
1072 		cmp = strcmp(name, m->name);
1073 		if (cmp < 0)
1074 			n = n->rb_left;
1075 		else if (cmp > 0)
1076 			n = n->rb_right;
1077 		else
1078 			return m;
1079 	}
1080 
1081 	return NULL;
1082 }
1083 
__read_proc_modules(void * arg,const char * name,u64 start,u64 size __maybe_unused)1084 static int __read_proc_modules(void *arg, const char *name, u64 start,
1085 			       u64 size __maybe_unused)
1086 {
1087 	struct rb_root *modules = arg;
1088 	struct module_info *mi;
1089 
1090 	mi = zalloc(sizeof(struct module_info));
1091 	if (!mi)
1092 		return -ENOMEM;
1093 
1094 	mi->name = strdup(name);
1095 	mi->start = start;
1096 
1097 	if (!mi->name) {
1098 		free(mi);
1099 		return -ENOMEM;
1100 	}
1101 
1102 	add_module(mi, modules);
1103 
1104 	return 0;
1105 }
1106 
read_proc_modules(const char * filename,struct rb_root * modules)1107 static int read_proc_modules(const char *filename, struct rb_root *modules)
1108 {
1109 	if (symbol__restricted_filename(filename, "/proc/modules"))
1110 		return -1;
1111 
1112 	if (modules__parse(filename, modules, __read_proc_modules)) {
1113 		delete_modules(modules);
1114 		return -1;
1115 	}
1116 
1117 	return 0;
1118 }
1119 
compare_proc_modules(const char * from,const char * to)1120 int compare_proc_modules(const char *from, const char *to)
1121 {
1122 	struct rb_root from_modules = RB_ROOT;
1123 	struct rb_root to_modules = RB_ROOT;
1124 	struct rb_node *from_node, *to_node;
1125 	struct module_info *from_m, *to_m;
1126 	int ret = -1;
1127 
1128 	if (read_proc_modules(from, &from_modules))
1129 		return -1;
1130 
1131 	if (read_proc_modules(to, &to_modules))
1132 		goto out_delete_from;
1133 
1134 	from_node = rb_first(&from_modules);
1135 	to_node = rb_first(&to_modules);
1136 	while (from_node) {
1137 		if (!to_node)
1138 			break;
1139 
1140 		from_m = rb_entry(from_node, struct module_info, rb_node);
1141 		to_m = rb_entry(to_node, struct module_info, rb_node);
1142 
1143 		if (from_m->start != to_m->start ||
1144 		    strcmp(from_m->name, to_m->name))
1145 			break;
1146 
1147 		from_node = rb_next(from_node);
1148 		to_node = rb_next(to_node);
1149 	}
1150 
1151 	if (!from_node && !to_node)
1152 		ret = 0;
1153 
1154 	delete_modules(&to_modules);
1155 out_delete_from:
1156 	delete_modules(&from_modules);
1157 
1158 	return ret;
1159 }
1160 
do_validate_kcore_modules_cb(struct map * old_map,void * data)1161 static int do_validate_kcore_modules_cb(struct map *old_map, void *data)
1162 {
1163 	struct rb_root *modules = data;
1164 	struct module_info *mi;
1165 	struct dso *dso;
1166 
1167 	if (!__map__is_kmodule(old_map))
1168 		return 0;
1169 
1170 	dso = map__dso(old_map);
1171 	/* Module must be in memory at the same address */
1172 	mi = find_module(dso__short_name(dso), modules);
1173 	if (!mi || mi->start != map__start(old_map))
1174 		return -EINVAL;
1175 
1176 	return 0;
1177 }
1178 
do_validate_kcore_modules(const char * filename,struct maps * kmaps)1179 static int do_validate_kcore_modules(const char *filename, struct maps *kmaps)
1180 {
1181 	struct rb_root modules = RB_ROOT;
1182 	int err;
1183 
1184 	err = read_proc_modules(filename, &modules);
1185 	if (err)
1186 		return err;
1187 
1188 	err = maps__for_each_map(kmaps, do_validate_kcore_modules_cb, &modules);
1189 
1190 	delete_modules(&modules);
1191 	return err;
1192 }
1193 
1194 /*
1195  * If kallsyms is referenced by name then we look for filename in the same
1196  * directory.
1197  */
filename_from_kallsyms_filename(char * filename,const char * base_name,const char * kallsyms_filename)1198 static bool filename_from_kallsyms_filename(char *filename,
1199 					    const char *base_name,
1200 					    const char *kallsyms_filename)
1201 {
1202 	char *name;
1203 
1204 	strcpy(filename, kallsyms_filename);
1205 	name = strrchr(filename, '/');
1206 	if (!name)
1207 		return false;
1208 
1209 	name += 1;
1210 
1211 	if (!strcmp(name, "kallsyms")) {
1212 		strcpy(name, base_name);
1213 		return true;
1214 	}
1215 
1216 	return false;
1217 }
1218 
validate_kcore_modules(const char * kallsyms_filename,struct map * map)1219 static int validate_kcore_modules(const char *kallsyms_filename,
1220 				  struct map *map)
1221 {
1222 	struct maps *kmaps = map__kmaps(map);
1223 	char modules_filename[PATH_MAX];
1224 
1225 	if (!kmaps)
1226 		return -EINVAL;
1227 
1228 	if (!filename_from_kallsyms_filename(modules_filename, "modules",
1229 					     kallsyms_filename))
1230 		return -EINVAL;
1231 
1232 	if (do_validate_kcore_modules(modules_filename, kmaps))
1233 		return -EINVAL;
1234 
1235 	return 0;
1236 }
1237 
validate_kcore_addresses(const char * kallsyms_filename,struct map * map)1238 static int validate_kcore_addresses(const char *kallsyms_filename,
1239 				    struct map *map)
1240 {
1241 	struct kmap *kmap = map__kmap(map);
1242 
1243 	if (!kmap)
1244 		return -EINVAL;
1245 
1246 	if (kmap->ref_reloc_sym && kmap->ref_reloc_sym->name) {
1247 		u64 start;
1248 
1249 		if (kallsyms__get_function_start(kallsyms_filename,
1250 						 kmap->ref_reloc_sym->name, &start))
1251 			return -ENOENT;
1252 		if (start != kmap->ref_reloc_sym->addr)
1253 			return -EINVAL;
1254 	}
1255 
1256 	return validate_kcore_modules(kallsyms_filename, map);
1257 }
1258 
1259 struct kcore_mapfn_data {
1260 	struct dso *dso;
1261 	struct list_head maps;
1262 };
1263 
kcore_mapfn(u64 start,u64 len,u64 pgoff,void * data)1264 static int kcore_mapfn(u64 start, u64 len, u64 pgoff, void *data)
1265 {
1266 	struct kcore_mapfn_data *md = data;
1267 	struct map_list_node *list_node = map_list_node__new();
1268 
1269 	if (!list_node)
1270 		return -ENOMEM;
1271 
1272 	list_node->map = map__new2(start, md->dso);
1273 	if (!list_node->map) {
1274 		free(list_node);
1275 		return -ENOMEM;
1276 	}
1277 
1278 	map__set_end(list_node->map, map__start(list_node->map) + len);
1279 	map__set_pgoff(list_node->map, pgoff);
1280 
1281 	list_add(&list_node->node, &md->maps);
1282 
1283 	return 0;
1284 }
1285 
remove_old_maps(struct map * map,void * data)1286 static bool remove_old_maps(struct map *map, void *data)
1287 {
1288 	const struct map *map_to_save = data;
1289 
1290 	/*
1291 	 * We need to preserve eBPF maps even if they are covered by kcore,
1292 	 * because we need to access eBPF dso for source data.
1293 	 */
1294 	return !RC_CHK_EQUAL(map, map_to_save) && !__map__is_bpf_prog(map);
1295 }
1296 
dso__load_kcore(struct dso * dso,struct map * map,const char * kallsyms_filename)1297 static int dso__load_kcore(struct dso *dso, struct map *map,
1298 			   const char *kallsyms_filename)
1299 {
1300 	struct maps *kmaps = map__kmaps(map);
1301 	struct kcore_mapfn_data md;
1302 	struct map *map_ref, *replacement_map = NULL;
1303 	struct machine *machine;
1304 	bool is_64_bit;
1305 	int err, fd;
1306 	char kcore_filename[PATH_MAX];
1307 	u64 stext;
1308 
1309 	if (!kmaps)
1310 		return -EINVAL;
1311 
1312 	machine = maps__machine(kmaps);
1313 
1314 	/* This function requires that the map is the kernel map */
1315 	if (!__map__is_kernel(map))
1316 		return -EINVAL;
1317 
1318 	if (!filename_from_kallsyms_filename(kcore_filename, "kcore",
1319 					     kallsyms_filename))
1320 		return -EINVAL;
1321 
1322 	/* Modules and kernel must be present at their original addresses */
1323 	if (validate_kcore_addresses(kallsyms_filename, map))
1324 		return -EINVAL;
1325 
1326 	md.dso = dso;
1327 	INIT_LIST_HEAD(&md.maps);
1328 
1329 	fd = open(kcore_filename, O_RDONLY);
1330 	if (fd < 0) {
1331 		pr_debug("Failed to open %s. Note /proc/kcore requires CAP_SYS_RAWIO capability to access.\n",
1332 			 kcore_filename);
1333 		return -EINVAL;
1334 	}
1335 
1336 	/* Read new maps into temporary lists */
1337 	err = file__read_maps(fd, map__prot(map) & PROT_EXEC, kcore_mapfn, &md,
1338 			      &is_64_bit);
1339 	if (err)
1340 		goto out_err;
1341 	dso__set_is_64_bit(dso, is_64_bit);
1342 
1343 	if (list_empty(&md.maps)) {
1344 		err = -EINVAL;
1345 		goto out_err;
1346 	}
1347 
1348 	/* Remove old maps */
1349 	maps__remove_maps(kmaps, remove_old_maps, map);
1350 	machine->trampolines_mapped = false;
1351 
1352 	/* Find the kernel map using the '_stext' symbol */
1353 	if (!kallsyms__get_function_start(kallsyms_filename, "_stext", &stext)) {
1354 		u64 replacement_size = 0;
1355 		struct map_list_node *new_node;
1356 
1357 		list_for_each_entry(new_node, &md.maps, node) {
1358 			struct map *new_map = new_node->map;
1359 			u64 new_size = map__size(new_map);
1360 
1361 			if (!(stext >= map__start(new_map) && stext < map__end(new_map)))
1362 				continue;
1363 
1364 			/*
1365 			 * On some architectures, ARM64 for example, the kernel
1366 			 * text can get allocated inside of the vmalloc segment.
1367 			 * Select the smallest matching segment, in case stext
1368 			 * falls within more than one in the list.
1369 			 */
1370 			if (!replacement_map || new_size < replacement_size) {
1371 				replacement_map = new_map;
1372 				replacement_size = new_size;
1373 			}
1374 		}
1375 	}
1376 
1377 	if (!replacement_map)
1378 		replacement_map = list_entry(md.maps.next, struct map_list_node, node)->map;
1379 
1380 	/*
1381 	 * Update addresses of vmlinux map. Re-insert it to ensure maps are
1382 	 * correctly ordered. Do this before using maps__merge_in() for the
1383 	 * remaining maps so vmlinux gets split if necessary.
1384 	 */
1385 	map_ref = map__get(map);
1386 	maps__remove(kmaps, map_ref);
1387 
1388 	map__set_start(map_ref, map__start(replacement_map));
1389 	map__set_end(map_ref, map__end(replacement_map));
1390 	map__set_pgoff(map_ref, map__pgoff(replacement_map));
1391 	map__set_mapping_type(map_ref, map__mapping_type(replacement_map));
1392 
1393 	err = maps__insert(kmaps, map_ref);
1394 	map__put(map_ref);
1395 	if (err)
1396 		goto out_err;
1397 
1398 	/* Add new maps */
1399 	while (!list_empty(&md.maps)) {
1400 		struct map_list_node *new_node = list_entry(md.maps.next, struct map_list_node, node);
1401 		struct map *new_map = new_node->map;
1402 
1403 		list_del_init(&new_node->node);
1404 
1405 		/* skip if replacement_map, already inserted above */
1406 		if (!RC_CHK_EQUAL(new_map, replacement_map)) {
1407 			/*
1408 			 * Merge kcore map into existing maps,
1409 			 * and ensure that current maps (eBPF)
1410 			 * stay intact.
1411 			 */
1412 			if (maps__merge_in(kmaps, new_map)) {
1413 				err = -EINVAL;
1414 				goto out_err;
1415 			}
1416 		}
1417 		free(new_node);
1418 	}
1419 
1420 	if (machine__is(machine, "x86_64")) {
1421 		u64 addr;
1422 
1423 		/*
1424 		 * If one of the corresponding symbols is there, assume the
1425 		 * entry trampoline maps are too.
1426 		 */
1427 		if (!kallsyms__get_function_start(kallsyms_filename,
1428 						  ENTRY_TRAMPOLINE_NAME,
1429 						  &addr))
1430 			machine->trampolines_mapped = true;
1431 	}
1432 
1433 	/*
1434 	 * Set the data type and long name so that kcore can be read via
1435 	 * dso__data_read_addr().
1436 	 */
1437 	if (dso__kernel(dso) == DSO_SPACE__KERNEL_GUEST)
1438 		dso__set_binary_type(dso, DSO_BINARY_TYPE__GUEST_KCORE);
1439 	else
1440 		dso__set_binary_type(dso, DSO_BINARY_TYPE__KCORE);
1441 	dso__set_long_name(dso, strdup(kcore_filename), true);
1442 
1443 	close(fd);
1444 
1445 	if (map__prot(map) & PROT_EXEC)
1446 		pr_debug("Using %s for kernel object code\n", kcore_filename);
1447 	else
1448 		pr_debug("Using %s for kernel data\n", kcore_filename);
1449 
1450 	return 0;
1451 
1452 out_err:
1453 	while (!list_empty(&md.maps)) {
1454 		struct map_list_node *list_node;
1455 
1456 		list_node = list_entry(md.maps.next, struct map_list_node, node);
1457 		list_del_init(&list_node->node);
1458 		map__zput(list_node->map);
1459 		free(list_node);
1460 	}
1461 	close(fd);
1462 	return err;
1463 }
1464 
1465 /*
1466  * If the kernel is relocated at boot time, kallsyms won't match.  Compute the
1467  * delta based on the relocation reference symbol.
1468  */
kallsyms__delta(struct kmap * kmap,const char * filename,u64 * delta)1469 static int kallsyms__delta(struct kmap *kmap, const char *filename, u64 *delta)
1470 {
1471 	u64 addr;
1472 
1473 	if (!kmap->ref_reloc_sym || !kmap->ref_reloc_sym->name)
1474 		return 0;
1475 
1476 	if (kallsyms__get_function_start(filename, kmap->ref_reloc_sym->name, &addr))
1477 		return -1;
1478 
1479 	*delta = addr - kmap->ref_reloc_sym->addr;
1480 	return 0;
1481 }
1482 
__dso__load_kallsyms(struct dso * dso,const char * filename,struct map * map,bool no_kcore)1483 int __dso__load_kallsyms(struct dso *dso, const char *filename,
1484 			 struct map *map, bool no_kcore)
1485 {
1486 	struct kmap *kmap = map__kmap(map);
1487 	u64 delta = 0;
1488 
1489 	if (symbol__restricted_filename(filename, "/proc/kallsyms"))
1490 		return -1;
1491 
1492 	if (!kmap || !kmap->kmaps)
1493 		return -1;
1494 
1495 	if (dso__load_all_kallsyms(dso, filename) < 0)
1496 		return -1;
1497 
1498 	if (kallsyms__delta(kmap, filename, &delta))
1499 		return -1;
1500 
1501 	symbols__fixup_end(dso__symbols(dso), true);
1502 	symbols__fixup_duplicate(dso__symbols(dso));
1503 
1504 	if (dso__kernel(dso) == DSO_SPACE__KERNEL_GUEST)
1505 		dso__set_symtab_type(dso, DSO_BINARY_TYPE__GUEST_KALLSYMS);
1506 	else
1507 		dso__set_symtab_type(dso, DSO_BINARY_TYPE__KALLSYMS);
1508 
1509 	if (!no_kcore && !dso__load_kcore(dso, map, filename))
1510 		return maps__split_kallsyms_for_kcore(kmap->kmaps, dso);
1511 	else
1512 		return maps__split_kallsyms(kmap->kmaps, dso, delta, map);
1513 }
1514 
dso__load_kallsyms(struct dso * dso,const char * filename,struct map * map)1515 int dso__load_kallsyms(struct dso *dso, const char *filename,
1516 		       struct map *map)
1517 {
1518 	return __dso__load_kallsyms(dso, filename, map, false);
1519 }
1520 
dso__load_perf_map(const char * map_path,struct dso * dso)1521 static int dso__load_perf_map(const char *map_path, struct dso *dso)
1522 {
1523 	char *line = NULL;
1524 	size_t n;
1525 	FILE *file;
1526 	int nr_syms = 0;
1527 
1528 	file = fopen(map_path, "r");
1529 	if (file == NULL)
1530 		goto out_failure;
1531 
1532 	while (!feof(file)) {
1533 		u64 start, size;
1534 		struct symbol *sym;
1535 		int line_len, len;
1536 
1537 		line_len = getline(&line, &n, file);
1538 		if (line_len < 0)
1539 			break;
1540 
1541 		if (!line)
1542 			goto out_failure;
1543 
1544 		line[--line_len] = '\0'; /* \n */
1545 
1546 		len = hex2u64(line, &start);
1547 
1548 		len++;
1549 		if (len + 2 >= line_len)
1550 			continue;
1551 
1552 		len += hex2u64(line + len, &size);
1553 
1554 		len++;
1555 		if (len + 2 >= line_len)
1556 			continue;
1557 
1558 		sym = symbol__new(start, size, STB_GLOBAL, STT_FUNC, line + len);
1559 
1560 		if (sym == NULL)
1561 			goto out_delete_line;
1562 
1563 		symbols__insert(dso__symbols(dso), sym);
1564 		nr_syms++;
1565 	}
1566 
1567 	free(line);
1568 	fclose(file);
1569 
1570 	return nr_syms;
1571 
1572 out_delete_line:
1573 	free(line);
1574 out_failure:
1575 	return -1;
1576 }
1577 
1578 #ifdef HAVE_LIBBFD_SUPPORT
1579 #define PACKAGE 'perf'
1580 #include <bfd.h>
1581 
bfd_symbols__cmpvalue(const void * a,const void * b)1582 static int bfd_symbols__cmpvalue(const void *a, const void *b)
1583 {
1584 	const asymbol *as = *(const asymbol **)a, *bs = *(const asymbol **)b;
1585 
1586 	if (bfd_asymbol_value(as) != bfd_asymbol_value(bs))
1587 		return bfd_asymbol_value(as) - bfd_asymbol_value(bs);
1588 
1589 	return bfd_asymbol_name(as)[0] - bfd_asymbol_name(bs)[0];
1590 }
1591 
bfd2elf_binding(asymbol * symbol)1592 static int bfd2elf_binding(asymbol *symbol)
1593 {
1594 	if (symbol->flags & BSF_WEAK)
1595 		return STB_WEAK;
1596 	if (symbol->flags & BSF_GLOBAL)
1597 		return STB_GLOBAL;
1598 	if (symbol->flags & BSF_LOCAL)
1599 		return STB_LOCAL;
1600 	return -1;
1601 }
1602 
dso__load_bfd_symbols(struct dso * dso,const char * debugfile)1603 int dso__load_bfd_symbols(struct dso *dso, const char *debugfile)
1604 {
1605 	int err = -1;
1606 	long symbols_size, symbols_count, i;
1607 	asection *section;
1608 	asymbol **symbols, *sym;
1609 	struct symbol *symbol;
1610 	bfd *abfd;
1611 	u64 start, len;
1612 
1613 	abfd = bfd_openr(debugfile, NULL);
1614 	if (!abfd)
1615 		return -1;
1616 
1617 	if (!bfd_check_format(abfd, bfd_object)) {
1618 		pr_debug2("%s: cannot read %s bfd file.\n", __func__,
1619 			  dso__long_name(dso));
1620 		goto out_close;
1621 	}
1622 
1623 	if (bfd_get_flavour(abfd) == bfd_target_elf_flavour)
1624 		goto out_close;
1625 
1626 	symbols_size = bfd_get_symtab_upper_bound(abfd);
1627 	if (symbols_size == 0) {
1628 		bfd_close(abfd);
1629 		return 0;
1630 	}
1631 
1632 	if (symbols_size < 0)
1633 		goto out_close;
1634 
1635 	symbols = malloc(symbols_size);
1636 	if (!symbols)
1637 		goto out_close;
1638 
1639 	symbols_count = bfd_canonicalize_symtab(abfd, symbols);
1640 	if (symbols_count < 0)
1641 		goto out_free;
1642 
1643 	section = bfd_get_section_by_name(abfd, ".text");
1644 	if (section) {
1645 		for (i = 0; i < symbols_count; ++i) {
1646 			if (!strcmp(bfd_asymbol_name(symbols[i]), "__ImageBase") ||
1647 			    !strcmp(bfd_asymbol_name(symbols[i]), "__image_base__"))
1648 				break;
1649 		}
1650 		if (i < symbols_count) {
1651 			/* PE symbols can only have 4 bytes, so use .text high bits */
1652 			u64 text_offset = (section->vma - (u32)section->vma)
1653 				+ (u32)bfd_asymbol_value(symbols[i]);
1654 			dso__set_text_offset(dso, text_offset);
1655 			dso__set_text_end(dso, (section->vma - text_offset) + section->size);
1656 		} else {
1657 			dso__set_text_offset(dso, section->vma - section->filepos);
1658 			dso__set_text_end(dso, section->filepos + section->size);
1659 		}
1660 	}
1661 
1662 	qsort(symbols, symbols_count, sizeof(asymbol *), bfd_symbols__cmpvalue);
1663 
1664 #ifdef bfd_get_section
1665 #define bfd_asymbol_section bfd_get_section
1666 #endif
1667 	for (i = 0; i < symbols_count; ++i) {
1668 		sym = symbols[i];
1669 		section = bfd_asymbol_section(sym);
1670 		if (bfd2elf_binding(sym) < 0)
1671 			continue;
1672 
1673 		while (i + 1 < symbols_count &&
1674 		       bfd_asymbol_section(symbols[i + 1]) == section &&
1675 		       bfd2elf_binding(symbols[i + 1]) < 0)
1676 			i++;
1677 
1678 		if (i + 1 < symbols_count &&
1679 		    bfd_asymbol_section(symbols[i + 1]) == section)
1680 			len = symbols[i + 1]->value - sym->value;
1681 		else
1682 			len = section->size - sym->value;
1683 
1684 		start = bfd_asymbol_value(sym) - dso__text_offset(dso);
1685 		symbol = symbol__new(start, len, bfd2elf_binding(sym), STT_FUNC,
1686 				     bfd_asymbol_name(sym));
1687 		if (!symbol)
1688 			goto out_free;
1689 
1690 		symbols__insert(dso__symbols(dso), symbol);
1691 	}
1692 #ifdef bfd_get_section
1693 #undef bfd_asymbol_section
1694 #endif
1695 
1696 	symbols__fixup_end(dso__symbols(dso), false);
1697 	symbols__fixup_duplicate(dso__symbols(dso));
1698 	dso__set_adjust_symbols(dso, true);
1699 
1700 	err = 0;
1701 out_free:
1702 	free(symbols);
1703 out_close:
1704 	bfd_close(abfd);
1705 	return err;
1706 }
1707 #endif
1708 
dso__is_compatible_symtab_type(struct dso * dso,bool kmod,enum dso_binary_type type)1709 static bool dso__is_compatible_symtab_type(struct dso *dso, bool kmod,
1710 					   enum dso_binary_type type)
1711 {
1712 	switch (type) {
1713 	case DSO_BINARY_TYPE__JAVA_JIT:
1714 	case DSO_BINARY_TYPE__DEBUGLINK:
1715 	case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
1716 	case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
1717 	case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
1718 	case DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO:
1719 	case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
1720 	case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
1721 	case DSO_BINARY_TYPE__GNU_DEBUGDATA:
1722 		return !kmod && dso__kernel(dso) == DSO_SPACE__USER;
1723 
1724 	case DSO_BINARY_TYPE__KALLSYMS:
1725 	case DSO_BINARY_TYPE__VMLINUX:
1726 	case DSO_BINARY_TYPE__KCORE:
1727 		return dso__kernel(dso) == DSO_SPACE__KERNEL;
1728 
1729 	case DSO_BINARY_TYPE__GUEST_KALLSYMS:
1730 	case DSO_BINARY_TYPE__GUEST_VMLINUX:
1731 	case DSO_BINARY_TYPE__GUEST_KCORE:
1732 		return dso__kernel(dso) == DSO_SPACE__KERNEL_GUEST;
1733 
1734 	case DSO_BINARY_TYPE__GUEST_KMODULE:
1735 	case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
1736 	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
1737 	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
1738 		/*
1739 		 * kernel modules know their symtab type - it's set when
1740 		 * creating a module dso in machine__addnew_module_map().
1741 		 */
1742 		return kmod && dso__symtab_type(dso) == type;
1743 
1744 	case DSO_BINARY_TYPE__BUILD_ID_CACHE:
1745 	case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
1746 		return true;
1747 
1748 	case DSO_BINARY_TYPE__BPF_PROG_INFO:
1749 	case DSO_BINARY_TYPE__BPF_IMAGE:
1750 	case DSO_BINARY_TYPE__OOL:
1751 	case DSO_BINARY_TYPE__NOT_FOUND:
1752 	default:
1753 		return false;
1754 	}
1755 }
1756 
1757 /* Checks for the existence of the perf-<pid>.map file in two different
1758  * locations.  First, if the process is a separate mount namespace, check in
1759  * that namespace using the pid of the innermost pid namespace.  If's not in a
1760  * namespace, or the file can't be found there, try in the mount namespace of
1761  * the tracing process using our view of its pid.
1762  */
dso__find_perf_map(char * filebuf,size_t bufsz,struct nsinfo ** nsip)1763 static int dso__find_perf_map(char *filebuf, size_t bufsz,
1764 			      struct nsinfo **nsip)
1765 {
1766 	struct nscookie nsc;
1767 	struct nsinfo *nsi;
1768 	struct nsinfo *nnsi;
1769 	int rc = -1;
1770 
1771 	nsi = *nsip;
1772 
1773 	if (nsinfo__need_setns(nsi)) {
1774 		snprintf(filebuf, bufsz, "/tmp/perf-%d.map", nsinfo__nstgid(nsi));
1775 		nsinfo__mountns_enter(nsi, &nsc);
1776 		rc = access(filebuf, R_OK);
1777 		nsinfo__mountns_exit(&nsc);
1778 		if (rc == 0)
1779 			return rc;
1780 	}
1781 
1782 	nnsi = nsinfo__copy(nsi);
1783 	if (nnsi) {
1784 		nsinfo__put(nsi);
1785 
1786 		nsinfo__clear_need_setns(nnsi);
1787 		snprintf(filebuf, bufsz, "/tmp/perf-%d.map", nsinfo__tgid(nnsi));
1788 		*nsip = nnsi;
1789 		rc = 0;
1790 	}
1791 
1792 	return rc;
1793 }
1794 
dso__load(struct dso * dso,struct map * map)1795 int dso__load(struct dso *dso, struct map *map)
1796 {
1797 	char *name;
1798 	int ret = -1;
1799 	u_int i;
1800 	struct machine *machine = NULL;
1801 	char *root_dir = (char *) "";
1802 	int ss_pos = 0;
1803 	struct symsrc ss_[2];
1804 	struct symsrc *syms_ss = NULL, *runtime_ss = NULL;
1805 	bool kmod;
1806 	bool perfmap;
1807 	struct build_id bid;
1808 	struct nscookie nsc;
1809 	char newmapname[PATH_MAX];
1810 	const char *map_path = dso__long_name(dso);
1811 
1812 	mutex_lock(dso__lock(dso));
1813 	perfmap = is_perf_pid_map_name(map_path);
1814 
1815 	if (perfmap) {
1816 		if (dso__nsinfo(dso) &&
1817 		    (dso__find_perf_map(newmapname, sizeof(newmapname),
1818 					dso__nsinfo_ptr(dso)) == 0)) {
1819 			map_path = newmapname;
1820 		}
1821 	}
1822 
1823 	nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
1824 
1825 	/* check again under the dso->lock */
1826 	if (dso__loaded(dso)) {
1827 		ret = 1;
1828 		goto out;
1829 	}
1830 
1831 	kmod = dso__is_kmod(dso);
1832 
1833 	if (dso__kernel(dso) && !kmod) {
1834 		if (dso__kernel(dso) == DSO_SPACE__KERNEL)
1835 			ret = dso__load_kernel_sym(dso, map);
1836 		else if (dso__kernel(dso) == DSO_SPACE__KERNEL_GUEST)
1837 			ret = dso__load_guest_kernel_sym(dso, map);
1838 
1839 		machine = maps__machine(map__kmaps(map));
1840 		if (machine__is(machine, "x86_64"))
1841 			machine__map_x86_64_entry_trampolines(machine, dso);
1842 		goto out;
1843 	}
1844 
1845 	dso__set_adjust_symbols(dso, false);
1846 
1847 	if (perfmap) {
1848 		ret = dso__load_perf_map(map_path, dso);
1849 		dso__set_symtab_type(dso, ret > 0
1850 				? DSO_BINARY_TYPE__JAVA_JIT
1851 				: DSO_BINARY_TYPE__NOT_FOUND);
1852 		goto out;
1853 	}
1854 
1855 	if (machine)
1856 		root_dir = machine->root_dir;
1857 
1858 	name = malloc(PATH_MAX);
1859 	if (!name)
1860 		goto out;
1861 
1862 	/*
1863 	 * Read the build id if possible. This is required for
1864 	 * DSO_BINARY_TYPE__BUILDID_DEBUGINFO to work
1865 	 */
1866 	if (!dso__has_build_id(dso) &&
1867 	    is_regular_file(dso__long_name(dso))) {
1868 		__symbol__join_symfs(name, PATH_MAX, dso__long_name(dso));
1869 		if (filename__read_build_id(name, &bid) > 0)
1870 			dso__set_build_id(dso, &bid);
1871 	}
1872 
1873 	/*
1874 	 * Iterate over candidate debug images.
1875 	 * Keep track of "interesting" ones (those which have a symtab, dynsym,
1876 	 * and/or opd section) for processing.
1877 	 */
1878 	for (i = 0; i < DSO_BINARY_TYPE__SYMTAB_CNT; i++) {
1879 		struct symsrc *ss = &ss_[ss_pos];
1880 		bool next_slot = false;
1881 		bool is_reg;
1882 		bool nsexit;
1883 		int bfdrc = -1;
1884 		int sirc = -1;
1885 
1886 		enum dso_binary_type symtab_type = binary_type_symtab[i];
1887 
1888 		nsexit = (symtab_type == DSO_BINARY_TYPE__BUILD_ID_CACHE ||
1889 		    symtab_type == DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO);
1890 
1891 		if (!dso__is_compatible_symtab_type(dso, kmod, symtab_type))
1892 			continue;
1893 
1894 		if (dso__read_binary_type_filename(dso, symtab_type,
1895 						   root_dir, name, PATH_MAX))
1896 			continue;
1897 
1898 		if (nsexit)
1899 			nsinfo__mountns_exit(&nsc);
1900 
1901 		is_reg = is_regular_file(name);
1902 		if (!is_reg && errno == ENOENT && dso__nsinfo(dso)) {
1903 			char *new_name = dso__filename_with_chroot(dso, name);
1904 			if (new_name) {
1905 				is_reg = is_regular_file(new_name);
1906 				strlcpy(name, new_name, PATH_MAX);
1907 				free(new_name);
1908 			}
1909 		}
1910 
1911 #ifdef HAVE_LIBBFD_SUPPORT
1912 		if (is_reg)
1913 			bfdrc = dso__load_bfd_symbols(dso, name);
1914 #endif
1915 		if (is_reg && bfdrc < 0)
1916 			sirc = symsrc__init(ss, dso, name, symtab_type);
1917 
1918 		if (nsexit)
1919 			nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
1920 
1921 		if (bfdrc == 0) {
1922 			ret = 0;
1923 			break;
1924 		}
1925 
1926 		if (!is_reg || sirc < 0)
1927 			continue;
1928 
1929 		if (!syms_ss && symsrc__has_symtab(ss)) {
1930 			syms_ss = ss;
1931 			next_slot = true;
1932 			if (!dso__symsrc_filename(dso))
1933 				dso__set_symsrc_filename(dso, strdup(name));
1934 		}
1935 
1936 		if (!runtime_ss && symsrc__possibly_runtime(ss)) {
1937 			runtime_ss = ss;
1938 			next_slot = true;
1939 		}
1940 
1941 		if (next_slot) {
1942 			ss_pos++;
1943 
1944 			if (dso__binary_type(dso) == DSO_BINARY_TYPE__NOT_FOUND)
1945 				dso__set_binary_type(dso, symtab_type);
1946 
1947 			if (syms_ss && runtime_ss)
1948 				break;
1949 		} else {
1950 			symsrc__destroy(ss);
1951 		}
1952 
1953 	}
1954 
1955 	if (!runtime_ss && !syms_ss)
1956 		goto out_free;
1957 
1958 	if (runtime_ss && !syms_ss) {
1959 		syms_ss = runtime_ss;
1960 	}
1961 
1962 	/* We'll have to hope for the best */
1963 	if (!runtime_ss && syms_ss)
1964 		runtime_ss = syms_ss;
1965 
1966 	if (syms_ss)
1967 		ret = dso__load_sym(dso, map, syms_ss, runtime_ss, kmod);
1968 	else
1969 		ret = -1;
1970 
1971 	if (ret > 0) {
1972 		int nr_plt;
1973 
1974 		nr_plt = dso__synthesize_plt_symbols(dso, runtime_ss);
1975 		if (nr_plt > 0)
1976 			ret += nr_plt;
1977 	}
1978 
1979 	for (; ss_pos > 0; ss_pos--)
1980 		symsrc__destroy(&ss_[ss_pos - 1]);
1981 out_free:
1982 	free(name);
1983 	if (ret < 0 && strstr(dso__name(dso), " (deleted)") != NULL)
1984 		ret = 0;
1985 out:
1986 	dso__set_loaded(dso);
1987 	mutex_unlock(dso__lock(dso));
1988 	nsinfo__mountns_exit(&nsc);
1989 
1990 	return ret;
1991 }
1992 
1993 /*
1994  * Always takes ownership of vmlinux when vmlinux_allocated == true, even if
1995  * it returns an error.
1996  */
dso__load_vmlinux(struct dso * dso,struct map * map,const char * vmlinux,bool vmlinux_allocated)1997 int dso__load_vmlinux(struct dso *dso, struct map *map,
1998 		      const char *vmlinux, bool vmlinux_allocated)
1999 {
2000 	int err = -1;
2001 	struct symsrc ss;
2002 	char symfs_vmlinux[PATH_MAX];
2003 	enum dso_binary_type symtab_type;
2004 
2005 	if (vmlinux[0] == '/')
2006 		snprintf(symfs_vmlinux, sizeof(symfs_vmlinux), "%s", vmlinux);
2007 	else
2008 		symbol__join_symfs(symfs_vmlinux, vmlinux);
2009 
2010 	if (dso__kernel(dso) == DSO_SPACE__KERNEL_GUEST)
2011 		symtab_type = DSO_BINARY_TYPE__GUEST_VMLINUX;
2012 	else
2013 		symtab_type = DSO_BINARY_TYPE__VMLINUX;
2014 
2015 	if (symsrc__init(&ss, dso, symfs_vmlinux, symtab_type)) {
2016 		if (vmlinux_allocated)
2017 			free((char *) vmlinux);
2018 		return -1;
2019 	}
2020 
2021 	/*
2022 	 * dso__load_sym() may copy 'dso' which will result in the copies having
2023 	 * an incorrect long name unless we set it here first.
2024 	 */
2025 	dso__set_long_name(dso, vmlinux, vmlinux_allocated);
2026 	if (dso__kernel(dso) == DSO_SPACE__KERNEL_GUEST)
2027 		dso__set_binary_type(dso, DSO_BINARY_TYPE__GUEST_VMLINUX);
2028 	else
2029 		dso__set_binary_type(dso, DSO_BINARY_TYPE__VMLINUX);
2030 
2031 	err = dso__load_sym(dso, map, &ss, &ss, 0);
2032 	symsrc__destroy(&ss);
2033 
2034 	if (err > 0) {
2035 		dso__set_loaded(dso);
2036 		pr_debug("Using %s for symbols\n", symfs_vmlinux);
2037 	}
2038 
2039 	return err;
2040 }
2041 
dso__load_vmlinux_path(struct dso * dso,struct map * map)2042 int dso__load_vmlinux_path(struct dso *dso, struct map *map)
2043 {
2044 	int i, err = 0;
2045 	char *filename = NULL;
2046 
2047 	pr_debug("Looking at the vmlinux_path (%d entries long)\n",
2048 		 vmlinux_path__nr_entries + 1);
2049 
2050 	for (i = 0; i < vmlinux_path__nr_entries; ++i) {
2051 		err = dso__load_vmlinux(dso, map, vmlinux_path[i], false);
2052 		if (err > 0)
2053 			goto out;
2054 	}
2055 
2056 	if (!symbol_conf.ignore_vmlinux_buildid)
2057 		filename = dso__build_id_filename(dso, NULL, 0, false);
2058 	if (filename != NULL) {
2059 		err = dso__load_vmlinux(dso, map, filename, true);
2060 		if (err > 0)
2061 			goto out;
2062 	}
2063 out:
2064 	return err;
2065 }
2066 
visible_dir_filter(const char * name,struct dirent * d)2067 static bool visible_dir_filter(const char *name, struct dirent *d)
2068 {
2069 	if (d->d_type != DT_DIR)
2070 		return false;
2071 	return lsdir_no_dot_filter(name, d);
2072 }
2073 
find_matching_kcore(struct map * map,char * dir,size_t dir_sz)2074 static int find_matching_kcore(struct map *map, char *dir, size_t dir_sz)
2075 {
2076 	char kallsyms_filename[PATH_MAX];
2077 	int ret = -1;
2078 	struct strlist *dirs;
2079 	struct str_node *nd;
2080 
2081 	dirs = lsdir(dir, visible_dir_filter);
2082 	if (!dirs)
2083 		return -1;
2084 
2085 	strlist__for_each_entry(nd, dirs) {
2086 		scnprintf(kallsyms_filename, sizeof(kallsyms_filename),
2087 			  "%s/%s/kallsyms", dir, nd->s);
2088 		if (!validate_kcore_addresses(kallsyms_filename, map)) {
2089 			strlcpy(dir, kallsyms_filename, dir_sz);
2090 			ret = 0;
2091 			break;
2092 		}
2093 	}
2094 
2095 	strlist__delete(dirs);
2096 
2097 	return ret;
2098 }
2099 
2100 /*
2101  * Use open(O_RDONLY) to check readability directly instead of access(R_OK)
2102  * since access(R_OK) only checks with real UID/GID but open() use effective
2103  * UID/GID and actual capabilities (e.g. /proc/kcore requires CAP_SYS_RAWIO).
2104  */
filename__readable(const char * file)2105 static bool filename__readable(const char *file)
2106 {
2107 	int fd = open(file, O_RDONLY);
2108 	if (fd < 0)
2109 		return false;
2110 	close(fd);
2111 	return true;
2112 }
2113 
dso__find_kallsyms(struct dso * dso,struct map * map)2114 static char *dso__find_kallsyms(struct dso *dso, struct map *map)
2115 {
2116 	struct build_id bid;
2117 	char sbuild_id[SBUILD_ID_SIZE];
2118 	bool is_host = false;
2119 	char path[PATH_MAX];
2120 
2121 	if (!dso__has_build_id(dso)) {
2122 		/*
2123 		 * Last resort, if we don't have a build-id and couldn't find
2124 		 * any vmlinux file, try the running kernel kallsyms table.
2125 		 */
2126 		goto proc_kallsyms;
2127 	}
2128 
2129 	if (sysfs__read_build_id("/sys/kernel/notes", &bid) == 0)
2130 		is_host = dso__build_id_equal(dso, &bid);
2131 
2132 	/* Try a fast path for /proc/kallsyms if possible */
2133 	if (is_host) {
2134 		/*
2135 		 * Do not check the build-id cache, unless we know we cannot use
2136 		 * /proc/kcore or module maps don't match to /proc/kallsyms.
2137 		 * To check readability of /proc/kcore, do not use access(R_OK)
2138 		 * since /proc/kcore requires CAP_SYS_RAWIO to read and access
2139 		 * can't check it.
2140 		 */
2141 		if (filename__readable("/proc/kcore") &&
2142 		    !validate_kcore_addresses("/proc/kallsyms", map))
2143 			goto proc_kallsyms;
2144 	}
2145 
2146 	build_id__sprintf(dso__bid(dso), sbuild_id);
2147 
2148 	/* Find kallsyms in build-id cache with kcore */
2149 	scnprintf(path, sizeof(path), "%s/%s/%s",
2150 		  buildid_dir, DSO__NAME_KCORE, sbuild_id);
2151 
2152 	if (!find_matching_kcore(map, path, sizeof(path)))
2153 		return strdup(path);
2154 
2155 	/* Use current /proc/kallsyms if possible */
2156 	if (is_host) {
2157 proc_kallsyms:
2158 		return strdup("/proc/kallsyms");
2159 	}
2160 
2161 	/* Finally, find a cache of kallsyms */
2162 	if (!build_id_cache__kallsyms_path(sbuild_id, path, sizeof(path))) {
2163 		pr_err("No kallsyms or vmlinux with build-id %s was found\n",
2164 		       sbuild_id);
2165 		return NULL;
2166 	}
2167 
2168 	return strdup(path);
2169 }
2170 
dso__load_kernel_sym(struct dso * dso,struct map * map)2171 static int dso__load_kernel_sym(struct dso *dso, struct map *map)
2172 {
2173 	int err;
2174 	const char *kallsyms_filename = NULL;
2175 	char *kallsyms_allocated_filename = NULL;
2176 	char *filename = NULL;
2177 
2178 	/*
2179 	 * Step 1: if the user specified a kallsyms or vmlinux filename, use
2180 	 * it and only it, reporting errors to the user if it cannot be used.
2181 	 *
2182 	 * For instance, try to analyse an ARM perf.data file _without_ a
2183 	 * build-id, or if the user specifies the wrong path to the right
2184 	 * vmlinux file, obviously we can't fallback to another vmlinux (a
2185 	 * x86_86 one, on the machine where analysis is being performed, say),
2186 	 * or worse, /proc/kallsyms.
2187 	 *
2188 	 * If the specified file _has_ a build-id and there is a build-id
2189 	 * section in the perf.data file, we will still do the expected
2190 	 * validation in dso__load_vmlinux and will bail out if they don't
2191 	 * match.
2192 	 */
2193 	if (symbol_conf.kallsyms_name != NULL) {
2194 		kallsyms_filename = symbol_conf.kallsyms_name;
2195 		goto do_kallsyms;
2196 	}
2197 
2198 	if (!symbol_conf.ignore_vmlinux && symbol_conf.vmlinux_name != NULL) {
2199 		return dso__load_vmlinux(dso, map, symbol_conf.vmlinux_name, false);
2200 	}
2201 
2202 	/*
2203 	 * Before checking on common vmlinux locations, check if it's
2204 	 * stored as standard build id binary (not kallsyms) under
2205 	 * .debug cache.
2206 	 */
2207 	if (!symbol_conf.ignore_vmlinux_buildid)
2208 		filename = __dso__build_id_filename(dso, NULL, 0, false, false);
2209 	if (filename != NULL) {
2210 		err = dso__load_vmlinux(dso, map, filename, true);
2211 		if (err > 0)
2212 			return err;
2213 	}
2214 
2215 	if (!symbol_conf.ignore_vmlinux && vmlinux_path != NULL) {
2216 		err = dso__load_vmlinux_path(dso, map);
2217 		if (err > 0)
2218 			return err;
2219 	}
2220 
2221 	/* do not try local files if a symfs was given */
2222 	if (symbol_conf.symfs[0] != 0)
2223 		return -1;
2224 
2225 	kallsyms_allocated_filename = dso__find_kallsyms(dso, map);
2226 	if (!kallsyms_allocated_filename)
2227 		return -1;
2228 
2229 	kallsyms_filename = kallsyms_allocated_filename;
2230 
2231 do_kallsyms:
2232 	err = dso__load_kallsyms(dso, kallsyms_filename, map);
2233 	if (err > 0)
2234 		pr_debug("Using %s for symbols\n", kallsyms_filename);
2235 	free(kallsyms_allocated_filename);
2236 
2237 	if (err > 0 && !dso__is_kcore(dso)) {
2238 		dso__set_binary_type(dso, DSO_BINARY_TYPE__KALLSYMS);
2239 		dso__set_long_name(dso, DSO__NAME_KALLSYMS, false);
2240 		map__fixup_start(map);
2241 		map__fixup_end(map);
2242 	}
2243 
2244 	return err;
2245 }
2246 
dso__load_guest_kernel_sym(struct dso * dso,struct map * map)2247 static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map)
2248 {
2249 	int err;
2250 	const char *kallsyms_filename;
2251 	struct machine *machine = maps__machine(map__kmaps(map));
2252 	char path[PATH_MAX];
2253 
2254 	if (machine->kallsyms_filename) {
2255 		kallsyms_filename = machine->kallsyms_filename;
2256 	} else if (machine__is_default_guest(machine)) {
2257 		/*
2258 		 * if the user specified a vmlinux filename, use it and only
2259 		 * it, reporting errors to the user if it cannot be used.
2260 		 * Or use file guest_kallsyms inputted by user on commandline
2261 		 */
2262 		if (symbol_conf.default_guest_vmlinux_name != NULL) {
2263 			err = dso__load_vmlinux(dso, map,
2264 						symbol_conf.default_guest_vmlinux_name,
2265 						false);
2266 			return err;
2267 		}
2268 
2269 		kallsyms_filename = symbol_conf.default_guest_kallsyms;
2270 		if (!kallsyms_filename)
2271 			return -1;
2272 	} else {
2273 		sprintf(path, "%s/proc/kallsyms", machine->root_dir);
2274 		kallsyms_filename = path;
2275 	}
2276 
2277 	err = dso__load_kallsyms(dso, kallsyms_filename, map);
2278 	if (err > 0)
2279 		pr_debug("Using %s for symbols\n", kallsyms_filename);
2280 	if (err > 0 && !dso__is_kcore(dso)) {
2281 		dso__set_binary_type(dso, DSO_BINARY_TYPE__GUEST_KALLSYMS);
2282 		dso__set_long_name(dso, machine->mmap_name, false);
2283 		map__fixup_start(map);
2284 		map__fixup_end(map);
2285 	}
2286 
2287 	return err;
2288 }
2289 
vmlinux_path__exit(void)2290 static void vmlinux_path__exit(void)
2291 {
2292 	while (--vmlinux_path__nr_entries >= 0)
2293 		zfree(&vmlinux_path[vmlinux_path__nr_entries]);
2294 	vmlinux_path__nr_entries = 0;
2295 
2296 	zfree(&vmlinux_path);
2297 }
2298 
2299 static const char * const vmlinux_paths[] = {
2300 	"vmlinux",
2301 	"/boot/vmlinux"
2302 };
2303 
2304 static const char * const vmlinux_paths_upd[] = {
2305 	"/boot/vmlinux-%s",
2306 	"/usr/lib/debug/boot/vmlinux-%s",
2307 	"/lib/modules/%s/build/vmlinux",
2308 	"/usr/lib/debug/lib/modules/%s/vmlinux",
2309 	"/usr/lib/debug/boot/vmlinux-%s.debug"
2310 };
2311 
vmlinux_path__add(const char * new_entry)2312 static int vmlinux_path__add(const char *new_entry)
2313 {
2314 	vmlinux_path[vmlinux_path__nr_entries] = strdup(new_entry);
2315 	if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
2316 		return -1;
2317 	++vmlinux_path__nr_entries;
2318 
2319 	return 0;
2320 }
2321 
vmlinux_path__init(struct perf_env * env)2322 static int vmlinux_path__init(struct perf_env *env)
2323 {
2324 	struct utsname uts;
2325 	char bf[PATH_MAX];
2326 	char *kernel_version;
2327 	unsigned int i;
2328 
2329 	vmlinux_path = malloc(sizeof(char *) * (ARRAY_SIZE(vmlinux_paths) +
2330 			      ARRAY_SIZE(vmlinux_paths_upd)));
2331 	if (vmlinux_path == NULL)
2332 		return -1;
2333 
2334 	for (i = 0; i < ARRAY_SIZE(vmlinux_paths); i++)
2335 		if (vmlinux_path__add(vmlinux_paths[i]) < 0)
2336 			goto out_fail;
2337 
2338 	/* only try kernel version if no symfs was given */
2339 	if (symbol_conf.symfs[0] != 0)
2340 		return 0;
2341 
2342 	if (env) {
2343 		kernel_version = env->os_release;
2344 	} else {
2345 		if (uname(&uts) < 0)
2346 			goto out_fail;
2347 
2348 		kernel_version = uts.release;
2349 	}
2350 
2351 	for (i = 0; i < ARRAY_SIZE(vmlinux_paths_upd); i++) {
2352 		snprintf(bf, sizeof(bf), vmlinux_paths_upd[i], kernel_version);
2353 		if (vmlinux_path__add(bf) < 0)
2354 			goto out_fail;
2355 	}
2356 
2357 	return 0;
2358 
2359 out_fail:
2360 	vmlinux_path__exit();
2361 	return -1;
2362 }
2363 
setup_list(struct strlist ** list,const char * list_str,const char * list_name)2364 int setup_list(struct strlist **list, const char *list_str,
2365 		      const char *list_name)
2366 {
2367 	if (list_str == NULL)
2368 		return 0;
2369 
2370 	*list = strlist__new(list_str, NULL);
2371 	if (!*list) {
2372 		pr_err("problems parsing %s list\n", list_name);
2373 		return -1;
2374 	}
2375 
2376 	symbol_conf.has_filter = true;
2377 	return 0;
2378 }
2379 
setup_intlist(struct intlist ** list,const char * list_str,const char * list_name)2380 int setup_intlist(struct intlist **list, const char *list_str,
2381 		  const char *list_name)
2382 {
2383 	if (list_str == NULL)
2384 		return 0;
2385 
2386 	*list = intlist__new(list_str);
2387 	if (!*list) {
2388 		pr_err("problems parsing %s list\n", list_name);
2389 		return -1;
2390 	}
2391 	return 0;
2392 }
2393 
setup_addrlist(struct intlist ** addr_list,struct strlist * sym_list)2394 static int setup_addrlist(struct intlist **addr_list, struct strlist *sym_list)
2395 {
2396 	struct str_node *pos, *tmp;
2397 	unsigned long val;
2398 	char *sep;
2399 	const char *end;
2400 	int i = 0, err;
2401 
2402 	*addr_list = intlist__new(NULL);
2403 	if (!*addr_list)
2404 		return -1;
2405 
2406 	strlist__for_each_entry_safe(pos, tmp, sym_list) {
2407 		errno = 0;
2408 		val = strtoul(pos->s, &sep, 16);
2409 		if (errno || (sep == pos->s))
2410 			continue;
2411 
2412 		if (*sep != '\0') {
2413 			end = pos->s + strlen(pos->s) - 1;
2414 			while (end >= sep && isspace(*end))
2415 				end--;
2416 
2417 			if (end >= sep)
2418 				continue;
2419 		}
2420 
2421 		err = intlist__add(*addr_list, val);
2422 		if (err)
2423 			break;
2424 
2425 		strlist__remove(sym_list, pos);
2426 		i++;
2427 	}
2428 
2429 	if (i == 0) {
2430 		intlist__delete(*addr_list);
2431 		*addr_list = NULL;
2432 	}
2433 
2434 	return 0;
2435 }
2436 
symbol__read_kptr_restrict(void)2437 static bool symbol__read_kptr_restrict(void)
2438 {
2439 	bool value = false;
2440 	FILE *fp = fopen("/proc/sys/kernel/kptr_restrict", "r");
2441 	bool used_root;
2442 	bool cap_syslog = perf_cap__capable(CAP_SYSLOG, &used_root);
2443 
2444 	if (fp != NULL) {
2445 		char line[8];
2446 
2447 		if (fgets(line, sizeof(line), fp) != NULL)
2448 			value = cap_syslog ? (atoi(line) >= 2) : (atoi(line) != 0);
2449 
2450 		fclose(fp);
2451 	}
2452 
2453 	/* Per kernel/kallsyms.c:
2454 	 * we also restrict when perf_event_paranoid > 1 w/o CAP_SYSLOG
2455 	 */
2456 	if (perf_event_paranoid() > 1 && !cap_syslog)
2457 		value = true;
2458 
2459 	return value;
2460 }
2461 
symbol__annotation_init(void)2462 int symbol__annotation_init(void)
2463 {
2464 	if (symbol_conf.init_annotation)
2465 		return 0;
2466 
2467 	if (symbol_conf.initialized) {
2468 		pr_err("Annotation needs to be init before symbol__init()\n");
2469 		return -1;
2470 	}
2471 
2472 	symbol_conf.priv_size += sizeof(struct annotation);
2473 	symbol_conf.init_annotation = true;
2474 	return 0;
2475 }
2476 
setup_parallelism_bitmap(void)2477 static int setup_parallelism_bitmap(void)
2478 {
2479 	struct perf_cpu_map *map;
2480 	struct perf_cpu cpu;
2481 	int i, err = -1;
2482 
2483 	if (symbol_conf.parallelism_list_str == NULL)
2484 		return 0;
2485 
2486 	map = perf_cpu_map__new(symbol_conf.parallelism_list_str);
2487 	if (map == NULL) {
2488 		pr_err("failed to parse parallelism filter list\n");
2489 		return -1;
2490 	}
2491 
2492 	bitmap_fill(symbol_conf.parallelism_filter, MAX_NR_CPUS + 1);
2493 	perf_cpu_map__for_each_cpu(cpu, i, map) {
2494 		if (cpu.cpu <= 0 || cpu.cpu > MAX_NR_CPUS) {
2495 			pr_err("Requested parallelism level %d is invalid.\n", cpu.cpu);
2496 			goto out_delete_map;
2497 		}
2498 		__clear_bit(cpu.cpu, symbol_conf.parallelism_filter);
2499 	}
2500 
2501 	err = 0;
2502 out_delete_map:
2503 	perf_cpu_map__put(map);
2504 	return err;
2505 }
2506 
symbol__init(struct perf_env * env)2507 int symbol__init(struct perf_env *env)
2508 {
2509 	const char *symfs;
2510 
2511 	if (symbol_conf.initialized)
2512 		return 0;
2513 
2514 	symbol_conf.priv_size = PERF_ALIGN(symbol_conf.priv_size, sizeof(u64));
2515 
2516 	symbol__elf_init();
2517 
2518 	if (symbol_conf.try_vmlinux_path && vmlinux_path__init(env) < 0)
2519 		return -1;
2520 
2521 	if (symbol_conf.field_sep && *symbol_conf.field_sep == '.') {
2522 		pr_err("'.' is the only non valid --field-separator argument\n");
2523 		return -1;
2524 	}
2525 
2526 	if (setup_parallelism_bitmap())
2527 		return -1;
2528 
2529 	if (setup_list(&symbol_conf.dso_list,
2530 		       symbol_conf.dso_list_str, "dso") < 0)
2531 		return -1;
2532 
2533 	if (setup_list(&symbol_conf.comm_list,
2534 		       symbol_conf.comm_list_str, "comm") < 0)
2535 		goto out_free_dso_list;
2536 
2537 	if (setup_intlist(&symbol_conf.pid_list,
2538 		       symbol_conf.pid_list_str, "pid") < 0)
2539 		goto out_free_comm_list;
2540 
2541 	if (setup_intlist(&symbol_conf.tid_list,
2542 		       symbol_conf.tid_list_str, "tid") < 0)
2543 		goto out_free_pid_list;
2544 
2545 	if (setup_list(&symbol_conf.sym_list,
2546 		       symbol_conf.sym_list_str, "symbol") < 0)
2547 		goto out_free_tid_list;
2548 
2549 	if (symbol_conf.sym_list &&
2550 	    setup_addrlist(&symbol_conf.addr_list, symbol_conf.sym_list) < 0)
2551 		goto out_free_sym_list;
2552 
2553 	if (setup_list(&symbol_conf.bt_stop_list,
2554 		       symbol_conf.bt_stop_list_str, "symbol") < 0)
2555 		goto out_free_sym_list;
2556 
2557 	/*
2558 	 * A path to symbols of "/" is identical to ""
2559 	 * reset here for simplicity.
2560 	 */
2561 	symfs = realpath(symbol_conf.symfs, NULL);
2562 	if (symfs == NULL)
2563 		symfs = symbol_conf.symfs;
2564 	if (strcmp(symfs, "/") == 0)
2565 		symbol_conf.symfs = "";
2566 	if (symfs != symbol_conf.symfs)
2567 		free((void *)symfs);
2568 
2569 	symbol_conf.kptr_restrict = symbol__read_kptr_restrict();
2570 
2571 	symbol_conf.initialized = true;
2572 	return 0;
2573 
2574 out_free_sym_list:
2575 	strlist__delete(symbol_conf.sym_list);
2576 	intlist__delete(symbol_conf.addr_list);
2577 out_free_tid_list:
2578 	intlist__delete(symbol_conf.tid_list);
2579 out_free_pid_list:
2580 	intlist__delete(symbol_conf.pid_list);
2581 out_free_comm_list:
2582 	strlist__delete(symbol_conf.comm_list);
2583 out_free_dso_list:
2584 	strlist__delete(symbol_conf.dso_list);
2585 	return -1;
2586 }
2587 
symbol__exit(void)2588 void symbol__exit(void)
2589 {
2590 	if (!symbol_conf.initialized)
2591 		return;
2592 	strlist__delete(symbol_conf.bt_stop_list);
2593 	strlist__delete(symbol_conf.sym_list);
2594 	strlist__delete(symbol_conf.dso_list);
2595 	strlist__delete(symbol_conf.comm_list);
2596 	intlist__delete(symbol_conf.tid_list);
2597 	intlist__delete(symbol_conf.pid_list);
2598 	intlist__delete(symbol_conf.addr_list);
2599 	vmlinux_path__exit();
2600 	symbol_conf.sym_list = symbol_conf.dso_list = symbol_conf.comm_list = NULL;
2601 	symbol_conf.bt_stop_list = NULL;
2602 	symbol_conf.initialized = false;
2603 }
2604 
symbol__config_symfs(const struct option * opt __maybe_unused,const char * dir,int unset __maybe_unused)2605 int symbol__config_symfs(const struct option *opt __maybe_unused,
2606 			 const char *dir, int unset __maybe_unused)
2607 {
2608 	char *bf = NULL;
2609 	int ret;
2610 
2611 	symbol_conf.symfs = strdup(dir);
2612 	if (symbol_conf.symfs == NULL)
2613 		return -ENOMEM;
2614 
2615 	/* skip the locally configured cache if a symfs is given, and
2616 	 * config buildid dir to symfs/.debug
2617 	 */
2618 	ret = asprintf(&bf, "%s/%s", dir, ".debug");
2619 	if (ret < 0)
2620 		return -ENOMEM;
2621 
2622 	set_buildid_dir(bf);
2623 
2624 	free(bf);
2625 	return 0;
2626 }
2627 
2628 /*
2629  * Checks that user supplied symbol kernel files are accessible because
2630  * the default mechanism for accessing elf files fails silently. i.e. if
2631  * debug syms for a build ID aren't found perf carries on normally. When
2632  * they are user supplied we should assume that the user doesn't want to
2633  * silently fail.
2634  */
symbol__validate_sym_arguments(void)2635 int symbol__validate_sym_arguments(void)
2636 {
2637 	if (symbol_conf.vmlinux_name &&
2638 	    access(symbol_conf.vmlinux_name, R_OK)) {
2639 		pr_err("Invalid file: %s\n", symbol_conf.vmlinux_name);
2640 		return -EINVAL;
2641 	}
2642 	if (symbol_conf.kallsyms_name &&
2643 	    access(symbol_conf.kallsyms_name, R_OK)) {
2644 		pr_err("Invalid file: %s\n", symbol_conf.kallsyms_name);
2645 		return -EINVAL;
2646 	}
2647 	return 0;
2648 }
2649