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1#include <fcntl.h>
2#include <stdio.h>
3#include <errno.h>
4#include <string.h>
5#include <unistd.h>
6#include <inttypes.h>
7
8#include "symbol.h"
9#include "demangle-java.h"
10#include "machine.h"
11#include "vdso.h"
12#include <symbol/kallsyms.h>
13#include "debug.h"
14
15#ifndef EM_AARCH64
16#define EM_AARCH64 183 /* ARM 64 bit */
17#endif
18
19
20#ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
21extern char *cplus_demangle(const char *, int);
22
23static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
24{
25 return cplus_demangle(c, i);
26}
27#else
28#ifdef NO_DEMANGLE
29static inline char *bfd_demangle(void __maybe_unused *v,
30 const char __maybe_unused *c,
31 int __maybe_unused i)
32{
33 return NULL;
34}
35#else
36#define PACKAGE 'perf'
37#include <bfd.h>
38#endif
39#endif
40
41#ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
42static int elf_getphdrnum(Elf *elf, size_t *dst)
43{
44 GElf_Ehdr gehdr;
45 GElf_Ehdr *ehdr;
46
47 ehdr = gelf_getehdr(elf, &gehdr);
48 if (!ehdr)
49 return -1;
50
51 *dst = ehdr->e_phnum;
52
53 return 0;
54}
55#endif
56
57#ifndef NT_GNU_BUILD_ID
58#define NT_GNU_BUILD_ID 3
59#endif
60
61/**
62 * elf_symtab__for_each_symbol - iterate thru all the symbols
63 *
64 * @syms: struct elf_symtab instance to iterate
65 * @idx: uint32_t idx
66 * @sym: GElf_Sym iterator
67 */
68#define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
69 for (idx = 0, gelf_getsym(syms, idx, &sym);\
70 idx < nr_syms; \
71 idx++, gelf_getsym(syms, idx, &sym))
72
73static inline uint8_t elf_sym__type(const GElf_Sym *sym)
74{
75 return GELF_ST_TYPE(sym->st_info);
76}
77
78#ifndef STT_GNU_IFUNC
79#define STT_GNU_IFUNC 10
80#endif
81
82static inline int elf_sym__is_function(const GElf_Sym *sym)
83{
84 return (elf_sym__type(sym) == STT_FUNC ||
85 elf_sym__type(sym) == STT_GNU_IFUNC) &&
86 sym->st_name != 0 &&
87 sym->st_shndx != SHN_UNDEF;
88}
89
90static inline bool elf_sym__is_object(const GElf_Sym *sym)
91{
92 return elf_sym__type(sym) == STT_OBJECT &&
93 sym->st_name != 0 &&
94 sym->st_shndx != SHN_UNDEF;
95}
96
97static inline int elf_sym__is_label(const GElf_Sym *sym)
98{
99 return elf_sym__type(sym) == STT_NOTYPE &&
100 sym->st_name != 0 &&
101 sym->st_shndx != SHN_UNDEF &&
102 sym->st_shndx != SHN_ABS;
103}
104
105static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
106{
107 switch (type) {
108 case MAP__FUNCTION:
109 return elf_sym__is_function(sym);
110 case MAP__VARIABLE:
111 return elf_sym__is_object(sym);
112 default:
113 return false;
114 }
115}
116
117static inline const char *elf_sym__name(const GElf_Sym *sym,
118 const Elf_Data *symstrs)
119{
120 return symstrs->d_buf + sym->st_name;
121}
122
123static inline const char *elf_sec__name(const GElf_Shdr *shdr,
124 const Elf_Data *secstrs)
125{
126 return secstrs->d_buf + shdr->sh_name;
127}
128
129static inline int elf_sec__is_text(const GElf_Shdr *shdr,
130 const Elf_Data *secstrs)
131{
132 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
133}
134
135static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
136 const Elf_Data *secstrs)
137{
138 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
139}
140
141static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
142 enum map_type type)
143{
144 switch (type) {
145 case MAP__FUNCTION:
146 return elf_sec__is_text(shdr, secstrs);
147 case MAP__VARIABLE:
148 return elf_sec__is_data(shdr, secstrs);
149 default:
150 return false;
151 }
152}
153
154static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
155{
156 Elf_Scn *sec = NULL;
157 GElf_Shdr shdr;
158 size_t cnt = 1;
159
160 while ((sec = elf_nextscn(elf, sec)) != NULL) {
161 gelf_getshdr(sec, &shdr);
162
163 if ((addr >= shdr.sh_addr) &&
164 (addr < (shdr.sh_addr + shdr.sh_size)))
165 return cnt;
166
167 ++cnt;
168 }
169
170 return -1;
171}
172
173Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
174 GElf_Shdr *shp, const char *name, size_t *idx)
175{
176 Elf_Scn *sec = NULL;
177 size_t cnt = 1;
178
179 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
180 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
181 return NULL;
182
183 while ((sec = elf_nextscn(elf, sec)) != NULL) {
184 char *str;
185
186 gelf_getshdr(sec, shp);
187 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
188 if (str && !strcmp(name, str)) {
189 if (idx)
190 *idx = cnt;
191 return sec;
192 }
193 ++cnt;
194 }
195
196 return NULL;
197}
198
199#define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
200 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
201 idx < nr_entries; \
202 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
203
204#define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
205 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
206 idx < nr_entries; \
207 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
208
209/*
210 * We need to check if we have a .dynsym, so that we can handle the
211 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
212 * .dynsym or .symtab).
213 * And always look at the original dso, not at debuginfo packages, that
214 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
215 */
216int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
217 symbol_filter_t filter)
218{
219 uint32_t nr_rel_entries, idx;
220 GElf_Sym sym;
221 u64 plt_offset;
222 GElf_Shdr shdr_plt;
223 struct symbol *f;
224 GElf_Shdr shdr_rel_plt, shdr_dynsym;
225 Elf_Data *reldata, *syms, *symstrs;
226 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
227 size_t dynsym_idx;
228 GElf_Ehdr ehdr;
229 char sympltname[1024];
230 Elf *elf;
231 int nr = 0, symidx, err = 0;
232
233 if (!ss->dynsym)
234 return 0;
235
236 elf = ss->elf;
237 ehdr = ss->ehdr;
238
239 scn_dynsym = ss->dynsym;
240 shdr_dynsym = ss->dynshdr;
241 dynsym_idx = ss->dynsym_idx;
242
243 if (scn_dynsym == NULL)
244 goto out_elf_end;
245
246 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
247 ".rela.plt", NULL);
248 if (scn_plt_rel == NULL) {
249 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
250 ".rel.plt", NULL);
251 if (scn_plt_rel == NULL)
252 goto out_elf_end;
253 }
254
255 err = -1;
256
257 if (shdr_rel_plt.sh_link != dynsym_idx)
258 goto out_elf_end;
259
260 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
261 goto out_elf_end;
262
263 /*
264 * Fetch the relocation section to find the idxes to the GOT
265 * and the symbols in the .dynsym they refer to.
266 */
267 reldata = elf_getdata(scn_plt_rel, NULL);
268 if (reldata == NULL)
269 goto out_elf_end;
270
271 syms = elf_getdata(scn_dynsym, NULL);
272 if (syms == NULL)
273 goto out_elf_end;
274
275 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
276 if (scn_symstrs == NULL)
277 goto out_elf_end;
278
279 symstrs = elf_getdata(scn_symstrs, NULL);
280 if (symstrs == NULL)
281 goto out_elf_end;
282
283 if (symstrs->d_size == 0)
284 goto out_elf_end;
285
286 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
287 plt_offset = shdr_plt.sh_offset;
288
289 if (shdr_rel_plt.sh_type == SHT_RELA) {
290 GElf_Rela pos_mem, *pos;
291
292 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
293 nr_rel_entries) {
294 symidx = GELF_R_SYM(pos->r_info);
295 plt_offset += shdr_plt.sh_entsize;
296 gelf_getsym(syms, symidx, &sym);
297 snprintf(sympltname, sizeof(sympltname),
298 "%s@plt", elf_sym__name(&sym, symstrs));
299
300 f = symbol__new(plt_offset, shdr_plt.sh_entsize,
301 STB_GLOBAL, sympltname);
302 if (!f)
303 goto out_elf_end;
304
305 if (filter && filter(map, f))
306 symbol__delete(f);
307 else {
308 symbols__insert(&dso->symbols[map->type], f);
309 ++nr;
310 }
311 }
312 } else if (shdr_rel_plt.sh_type == SHT_REL) {
313 GElf_Rel pos_mem, *pos;
314 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
315 nr_rel_entries) {
316 symidx = GELF_R_SYM(pos->r_info);
317 plt_offset += shdr_plt.sh_entsize;
318 gelf_getsym(syms, symidx, &sym);
319 snprintf(sympltname, sizeof(sympltname),
320 "%s@plt", elf_sym__name(&sym, symstrs));
321
322 f = symbol__new(plt_offset, shdr_plt.sh_entsize,
323 STB_GLOBAL, sympltname);
324 if (!f)
325 goto out_elf_end;
326
327 if (filter && filter(map, f))
328 symbol__delete(f);
329 else {
330 symbols__insert(&dso->symbols[map->type], f);
331 ++nr;
332 }
333 }
334 }
335
336 err = 0;
337out_elf_end:
338 if (err == 0)
339 return nr;
340 pr_debug("%s: problems reading %s PLT info.\n",
341 __func__, dso->long_name);
342 return 0;
343}
344
345/*
346 * Align offset to 4 bytes as needed for note name and descriptor data.
347 */
348#define NOTE_ALIGN(n) (((n) + 3) & -4U)
349
350static int elf_read_build_id(Elf *elf, void *bf, size_t size)
351{
352 int err = -1;
353 GElf_Ehdr ehdr;
354 GElf_Shdr shdr;
355 Elf_Data *data;
356 Elf_Scn *sec;
357 Elf_Kind ek;
358 void *ptr;
359
360 if (size < BUILD_ID_SIZE)
361 goto out;
362
363 ek = elf_kind(elf);
364 if (ek != ELF_K_ELF)
365 goto out;
366
367 if (gelf_getehdr(elf, &ehdr) == NULL) {
368 pr_err("%s: cannot get elf header.\n", __func__);
369 goto out;
370 }
371
372 /*
373 * Check following sections for notes:
374 * '.note.gnu.build-id'
375 * '.notes'
376 * '.note' (VDSO specific)
377 */
378 do {
379 sec = elf_section_by_name(elf, &ehdr, &shdr,
380 ".note.gnu.build-id", NULL);
381 if (sec)
382 break;
383
384 sec = elf_section_by_name(elf, &ehdr, &shdr,
385 ".notes", NULL);
386 if (sec)
387 break;
388
389 sec = elf_section_by_name(elf, &ehdr, &shdr,
390 ".note", NULL);
391 if (sec)
392 break;
393
394 return err;
395
396 } while (0);
397
398 data = elf_getdata(sec, NULL);
399 if (data == NULL)
400 goto out;
401
402 ptr = data->d_buf;
403 while (ptr < (data->d_buf + data->d_size)) {
404 GElf_Nhdr *nhdr = ptr;
405 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
406 descsz = NOTE_ALIGN(nhdr->n_descsz);
407 const char *name;
408
409 ptr += sizeof(*nhdr);
410 name = ptr;
411 ptr += namesz;
412 if (nhdr->n_type == NT_GNU_BUILD_ID &&
413 nhdr->n_namesz == sizeof("GNU")) {
414 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
415 size_t sz = min(size, descsz);
416 memcpy(bf, ptr, sz);
417 memset(bf + sz, 0, size - sz);
418 err = descsz;
419 break;
420 }
421 }
422 ptr += descsz;
423 }
424
425out:
426 return err;
427}
428
429int filename__read_build_id(const char *filename, void *bf, size_t size)
430{
431 int fd, err = -1;
432 Elf *elf;
433
434 if (size < BUILD_ID_SIZE)
435 goto out;
436
437 fd = open(filename, O_RDONLY);
438 if (fd < 0)
439 goto out;
440
441 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
442 if (elf == NULL) {
443 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
444 goto out_close;
445 }
446
447 err = elf_read_build_id(elf, bf, size);
448
449 elf_end(elf);
450out_close:
451 close(fd);
452out:
453 return err;
454}
455
456int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
457{
458 int fd, err = -1;
459
460 if (size < BUILD_ID_SIZE)
461 goto out;
462
463 fd = open(filename, O_RDONLY);
464 if (fd < 0)
465 goto out;
466
467 while (1) {
468 char bf[BUFSIZ];
469 GElf_Nhdr nhdr;
470 size_t namesz, descsz;
471
472 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
473 break;
474
475 namesz = NOTE_ALIGN(nhdr.n_namesz);
476 descsz = NOTE_ALIGN(nhdr.n_descsz);
477 if (nhdr.n_type == NT_GNU_BUILD_ID &&
478 nhdr.n_namesz == sizeof("GNU")) {
479 if (read(fd, bf, namesz) != (ssize_t)namesz)
480 break;
481 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
482 size_t sz = min(descsz, size);
483 if (read(fd, build_id, sz) == (ssize_t)sz) {
484 memset(build_id + sz, 0, size - sz);
485 err = 0;
486 break;
487 }
488 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
489 break;
490 } else {
491 int n = namesz + descsz;
492 if (read(fd, bf, n) != n)
493 break;
494 }
495 }
496 close(fd);
497out:
498 return err;
499}
500
501int filename__read_debuglink(const char *filename, char *debuglink,
502 size_t size)
503{
504 int fd, err = -1;
505 Elf *elf;
506 GElf_Ehdr ehdr;
507 GElf_Shdr shdr;
508 Elf_Data *data;
509 Elf_Scn *sec;
510 Elf_Kind ek;
511
512 fd = open(filename, O_RDONLY);
513 if (fd < 0)
514 goto out;
515
516 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
517 if (elf == NULL) {
518 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
519 goto out_close;
520 }
521
522 ek = elf_kind(elf);
523 if (ek != ELF_K_ELF)
524 goto out_elf_end;
525
526 if (gelf_getehdr(elf, &ehdr) == NULL) {
527 pr_err("%s: cannot get elf header.\n", __func__);
528 goto out_elf_end;
529 }
530
531 sec = elf_section_by_name(elf, &ehdr, &shdr,
532 ".gnu_debuglink", NULL);
533 if (sec == NULL)
534 goto out_elf_end;
535
536 data = elf_getdata(sec, NULL);
537 if (data == NULL)
538 goto out_elf_end;
539
540 /* the start of this section is a zero-terminated string */
541 strncpy(debuglink, data->d_buf, size);
542
543 err = 0;
544
545out_elf_end:
546 elf_end(elf);
547out_close:
548 close(fd);
549out:
550 return err;
551}
552
553static int dso__swap_init(struct dso *dso, unsigned char eidata)
554{
555 static unsigned int const endian = 1;
556
557 dso->needs_swap = DSO_SWAP__NO;
558
559 switch (eidata) {
560 case ELFDATA2LSB:
561 /* We are big endian, DSO is little endian. */
562 if (*(unsigned char const *)&endian != 1)
563 dso->needs_swap = DSO_SWAP__YES;
564 break;
565
566 case ELFDATA2MSB:
567 /* We are little endian, DSO is big endian. */
568 if (*(unsigned char const *)&endian != 0)
569 dso->needs_swap = DSO_SWAP__YES;
570 break;
571
572 default:
573 pr_err("unrecognized DSO data encoding %d\n", eidata);
574 return -EINVAL;
575 }
576
577 return 0;
578}
579
580static int decompress_kmodule(struct dso *dso, const char *name,
581 enum dso_binary_type type)
582{
583 int fd = -1;
584 char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
585 struct kmod_path m;
586
587 if (type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
588 type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP &&
589 type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
590 return -1;
591
592 if (type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
593 name = dso->long_name;
594
595 if (kmod_path__parse_ext(&m, name) || !m.comp)
596 return -1;
597
598 fd = mkstemp(tmpbuf);
599 if (fd < 0) {
600 dso->load_errno = errno;
601 goto out;
602 }
603
604 if (!decompress_to_file(m.ext, name, fd)) {
605 dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
606 close(fd);
607 fd = -1;
608 }
609
610 unlink(tmpbuf);
611
612out:
613 free(m.ext);
614 return fd;
615}
616
617bool symsrc__possibly_runtime(struct symsrc *ss)
618{
619 return ss->dynsym || ss->opdsec;
620}
621
622bool symsrc__has_symtab(struct symsrc *ss)
623{
624 return ss->symtab != NULL;
625}
626
627void symsrc__destroy(struct symsrc *ss)
628{
629 zfree(&ss->name);
630 elf_end(ss->elf);
631 close(ss->fd);
632}
633
634bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
635{
636 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
637}
638
639int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
640 enum dso_binary_type type)
641{
642 int err = -1;
643 GElf_Ehdr ehdr;
644 Elf *elf;
645 int fd;
646
647 if (dso__needs_decompress(dso)) {
648 fd = decompress_kmodule(dso, name, type);
649 if (fd < 0)
650 return -1;
651 } else {
652 fd = open(name, O_RDONLY);
653 if (fd < 0) {
654 dso->load_errno = errno;
655 return -1;
656 }
657 }
658
659 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
660 if (elf == NULL) {
661 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
662 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
663 goto out_close;
664 }
665
666 if (gelf_getehdr(elf, &ehdr) == NULL) {
667 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
668 pr_debug("%s: cannot get elf header.\n", __func__);
669 goto out_elf_end;
670 }
671
672 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
673 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
674 goto out_elf_end;
675 }
676
677 /* Always reject images with a mismatched build-id: */
678 if (dso->has_build_id) {
679 u8 build_id[BUILD_ID_SIZE];
680
681 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
682 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
683 goto out_elf_end;
684 }
685
686 if (!dso__build_id_equal(dso, build_id)) {
687 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
688 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
689 goto out_elf_end;
690 }
691 }
692
693 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
694
695 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
696 NULL);
697 if (ss->symshdr.sh_type != SHT_SYMTAB)
698 ss->symtab = NULL;
699
700 ss->dynsym_idx = 0;
701 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
702 &ss->dynsym_idx);
703 if (ss->dynshdr.sh_type != SHT_DYNSYM)
704 ss->dynsym = NULL;
705
706 ss->opdidx = 0;
707 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
708 &ss->opdidx);
709 if (ss->opdshdr.sh_type != SHT_PROGBITS)
710 ss->opdsec = NULL;
711
712 if (dso->kernel == DSO_TYPE_USER) {
713 GElf_Shdr shdr;
714 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
715 ehdr.e_type == ET_REL ||
716 dso__is_vdso(dso) ||
717 elf_section_by_name(elf, &ehdr, &shdr,
718 ".gnu.prelink_undo",
719 NULL) != NULL);
720 } else {
721 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
722 }
723
724 ss->name = strdup(name);
725 if (!ss->name) {
726 dso->load_errno = errno;
727 goto out_elf_end;
728 }
729
730 ss->elf = elf;
731 ss->fd = fd;
732 ss->ehdr = ehdr;
733 ss->type = type;
734
735 return 0;
736
737out_elf_end:
738 elf_end(elf);
739out_close:
740 close(fd);
741 return err;
742}
743
744/**
745 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
746 * @kmap: kernel maps and relocation reference symbol
747 *
748 * This function returns %true if we are dealing with the kernel maps and the
749 * relocation reference symbol has not yet been found. Otherwise %false is
750 * returned.
751 */
752static bool ref_reloc_sym_not_found(struct kmap *kmap)
753{
754 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
755 !kmap->ref_reloc_sym->unrelocated_addr;
756}
757
758/**
759 * ref_reloc - kernel relocation offset.
760 * @kmap: kernel maps and relocation reference symbol
761 *
762 * This function returns the offset of kernel addresses as determined by using
763 * the relocation reference symbol i.e. if the kernel has not been relocated
764 * then the return value is zero.
765 */
766static u64 ref_reloc(struct kmap *kmap)
767{
768 if (kmap && kmap->ref_reloc_sym &&
769 kmap->ref_reloc_sym->unrelocated_addr)
770 return kmap->ref_reloc_sym->addr -
771 kmap->ref_reloc_sym->unrelocated_addr;
772 return 0;
773}
774
775static bool want_demangle(bool is_kernel_sym)
776{
777 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
778}
779
780void __weak arch__elf_sym_adjust(GElf_Sym *sym __maybe_unused) { }
781
782int dso__load_sym(struct dso *dso, struct map *map,
783 struct symsrc *syms_ss, struct symsrc *runtime_ss,
784 symbol_filter_t filter, int kmodule)
785{
786 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
787 struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
788 struct map *curr_map = map;
789 struct dso *curr_dso = dso;
790 Elf_Data *symstrs, *secstrs;
791 uint32_t nr_syms;
792 int err = -1;
793 uint32_t idx;
794 GElf_Ehdr ehdr;
795 GElf_Shdr shdr;
796 GElf_Shdr tshdr;
797 Elf_Data *syms, *opddata = NULL;
798 GElf_Sym sym;
799 Elf_Scn *sec, *sec_strndx;
800 Elf *elf;
801 int nr = 0;
802 bool remap_kernel = false, adjust_kernel_syms = false;
803
804 if (kmap && !kmaps)
805 return -1;
806
807 dso->symtab_type = syms_ss->type;
808 dso->is_64_bit = syms_ss->is_64_bit;
809 dso->rel = syms_ss->ehdr.e_type == ET_REL;
810
811 /*
812 * Modules may already have symbols from kallsyms, but those symbols
813 * have the wrong values for the dso maps, so remove them.
814 */
815 if (kmodule && syms_ss->symtab)
816 symbols__delete(&dso->symbols[map->type]);
817
818 if (!syms_ss->symtab) {
819 /*
820 * If the vmlinux is stripped, fail so we will fall back
821 * to using kallsyms. The vmlinux runtime symbols aren't
822 * of much use.
823 */
824 if (dso->kernel)
825 goto out_elf_end;
826
827 syms_ss->symtab = syms_ss->dynsym;
828 syms_ss->symshdr = syms_ss->dynshdr;
829 }
830
831 elf = syms_ss->elf;
832 ehdr = syms_ss->ehdr;
833 sec = syms_ss->symtab;
834 shdr = syms_ss->symshdr;
835
836 if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
837 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
838
839 if (runtime_ss->opdsec)
840 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
841
842 syms = elf_getdata(sec, NULL);
843 if (syms == NULL)
844 goto out_elf_end;
845
846 sec = elf_getscn(elf, shdr.sh_link);
847 if (sec == NULL)
848 goto out_elf_end;
849
850 symstrs = elf_getdata(sec, NULL);
851 if (symstrs == NULL)
852 goto out_elf_end;
853
854 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
855 if (sec_strndx == NULL)
856 goto out_elf_end;
857
858 secstrs = elf_getdata(sec_strndx, NULL);
859 if (secstrs == NULL)
860 goto out_elf_end;
861
862 nr_syms = shdr.sh_size / shdr.sh_entsize;
863
864 memset(&sym, 0, sizeof(sym));
865
866 /*
867 * The kernel relocation symbol is needed in advance in order to adjust
868 * kernel maps correctly.
869 */
870 if (ref_reloc_sym_not_found(kmap)) {
871 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
872 const char *elf_name = elf_sym__name(&sym, symstrs);
873
874 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
875 continue;
876 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
877 map->reloc = kmap->ref_reloc_sym->addr -
878 kmap->ref_reloc_sym->unrelocated_addr;
879 break;
880 }
881 }
882
883 /*
884 * Handle any relocation of vdso necessary because older kernels
885 * attempted to prelink vdso to its virtual address.
886 */
887 if (dso__is_vdso(dso))
888 map->reloc = map->start - dso->text_offset;
889
890 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
891 /*
892 * Initial kernel and module mappings do not map to the dso. For
893 * function mappings, flag the fixups.
894 */
895 if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
896 remap_kernel = true;
897 adjust_kernel_syms = dso->adjust_symbols;
898 }
899 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
900 struct symbol *f;
901 const char *elf_name = elf_sym__name(&sym, symstrs);
902 char *demangled = NULL;
903 int is_label = elf_sym__is_label(&sym);
904 const char *section_name;
905 bool used_opd = false;
906
907 if (!is_label && !elf_sym__is_a(&sym, map->type))
908 continue;
909
910 /* Reject ARM ELF "mapping symbols": these aren't unique and
911 * don't identify functions, so will confuse the profile
912 * output: */
913 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
914 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
915 && (elf_name[2] == '\0' || elf_name[2] == '.'))
916 continue;
917 }
918
919 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
920 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
921 u64 *opd = opddata->d_buf + offset;
922 sym.st_value = DSO__SWAP(dso, u64, *opd);
923 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
924 sym.st_value);
925 used_opd = true;
926 }
927 /*
928 * When loading symbols in a data mapping, ABS symbols (which
929 * has a value of SHN_ABS in its st_shndx) failed at
930 * elf_getscn(). And it marks the loading as a failure so
931 * already loaded symbols cannot be fixed up.
932 *
933 * I'm not sure what should be done. Just ignore them for now.
934 * - Namhyung Kim
935 */
936 if (sym.st_shndx == SHN_ABS)
937 continue;
938
939 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
940 if (!sec)
941 goto out_elf_end;
942
943 gelf_getshdr(sec, &shdr);
944
945 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
946 continue;
947
948 section_name = elf_sec__name(&shdr, secstrs);
949
950 /* On ARM, symbols for thumb functions have 1 added to
951 * the symbol address as a flag - remove it */
952 if ((ehdr.e_machine == EM_ARM) &&
953 (map->type == MAP__FUNCTION) &&
954 (sym.st_value & 1))
955 --sym.st_value;
956
957 arch__elf_sym_adjust(&sym);
958
959 if (dso->kernel || kmodule) {
960 char dso_name[PATH_MAX];
961
962 /* Adjust symbol to map to file offset */
963 if (adjust_kernel_syms)
964 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
965
966 if (strcmp(section_name,
967 (curr_dso->short_name +
968 dso->short_name_len)) == 0)
969 goto new_symbol;
970
971 if (strcmp(section_name, ".text") == 0) {
972 /*
973 * The initial kernel mapping is based on
974 * kallsyms and identity maps. Overwrite it to
975 * map to the kernel dso.
976 */
977 if (remap_kernel && dso->kernel) {
978 remap_kernel = false;
979 map->start = shdr.sh_addr +
980 ref_reloc(kmap);
981 map->end = map->start + shdr.sh_size;
982 map->pgoff = shdr.sh_offset;
983 map->map_ip = map__map_ip;
984 map->unmap_ip = map__unmap_ip;
985 /* Ensure maps are correctly ordered */
986 if (kmaps) {
987 map__get(map);
988 map_groups__remove(kmaps, map);
989 map_groups__insert(kmaps, map);
990 map__put(map);
991 }
992 }
993
994 /*
995 * The initial module mapping is based on
996 * /proc/modules mapped to offset zero.
997 * Overwrite it to map to the module dso.
998 */
999 if (remap_kernel && kmodule) {
1000 remap_kernel = false;
1001 map->pgoff = shdr.sh_offset;
1002 }
1003
1004 curr_map = map;
1005 curr_dso = dso;
1006 goto new_symbol;
1007 }
1008
1009 if (!kmap)
1010 goto new_symbol;
1011
1012 snprintf(dso_name, sizeof(dso_name),
1013 "%s%s", dso->short_name, section_name);
1014
1015 curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1016 if (curr_map == NULL) {
1017 u64 start = sym.st_value;
1018
1019 if (kmodule)
1020 start += map->start + shdr.sh_offset;
1021
1022 curr_dso = dso__new(dso_name);
1023 if (curr_dso == NULL)
1024 goto out_elf_end;
1025 curr_dso->kernel = dso->kernel;
1026 curr_dso->long_name = dso->long_name;
1027 curr_dso->long_name_len = dso->long_name_len;
1028 curr_map = map__new2(start, curr_dso,
1029 map->type);
1030 dso__put(curr_dso);
1031 if (curr_map == NULL) {
1032 goto out_elf_end;
1033 }
1034 if (adjust_kernel_syms) {
1035 curr_map->start = shdr.sh_addr +
1036 ref_reloc(kmap);
1037 curr_map->end = curr_map->start +
1038 shdr.sh_size;
1039 curr_map->pgoff = shdr.sh_offset;
1040 } else {
1041 curr_map->map_ip = identity__map_ip;
1042 curr_map->unmap_ip = identity__map_ip;
1043 }
1044 curr_dso->symtab_type = dso->symtab_type;
1045 map_groups__insert(kmaps, curr_map);
1046 /*
1047 * Add it before we drop the referece to curr_map,
1048 * i.e. while we still are sure to have a reference
1049 * to this DSO via curr_map->dso.
1050 */
1051 dsos__add(&map->groups->machine->dsos, curr_dso);
1052 /* kmaps already got it */
1053 map__put(curr_map);
1054 dso__set_loaded(curr_dso, map->type);
1055 } else
1056 curr_dso = curr_map->dso;
1057
1058 goto new_symbol;
1059 }
1060
1061 if ((used_opd && runtime_ss->adjust_symbols)
1062 || (!used_opd && syms_ss->adjust_symbols)) {
1063 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1064 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1065 (u64)sym.st_value, (u64)shdr.sh_addr,
1066 (u64)shdr.sh_offset);
1067 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1068 }
1069new_symbol:
1070 /*
1071 * We need to figure out if the object was created from C++ sources
1072 * DWARF DW_compile_unit has this, but we don't always have access
1073 * to it...
1074 */
1075 if (want_demangle(dso->kernel || kmodule)) {
1076 int demangle_flags = DMGL_NO_OPTS;
1077 if (verbose)
1078 demangle_flags = DMGL_PARAMS | DMGL_ANSI;
1079
1080 demangled = bfd_demangle(NULL, elf_name, demangle_flags);
1081 if (demangled == NULL)
1082 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
1083 if (demangled != NULL)
1084 elf_name = demangled;
1085 }
1086 f = symbol__new(sym.st_value, sym.st_size,
1087 GELF_ST_BIND(sym.st_info), elf_name);
1088 free(demangled);
1089 if (!f)
1090 goto out_elf_end;
1091
1092 if (filter && filter(curr_map, f))
1093 symbol__delete(f);
1094 else {
1095 symbols__insert(&curr_dso->symbols[curr_map->type], f);
1096 nr++;
1097 }
1098 }
1099
1100 /*
1101 * For misannotated, zeroed, ASM function sizes.
1102 */
1103 if (nr > 0) {
1104 if (!symbol_conf.allow_aliases)
1105 symbols__fixup_duplicate(&dso->symbols[map->type]);
1106 symbols__fixup_end(&dso->symbols[map->type]);
1107 if (kmap) {
1108 /*
1109 * We need to fixup this here too because we create new
1110 * maps here, for things like vsyscall sections.
1111 */
1112 __map_groups__fixup_end(kmaps, map->type);
1113 }
1114 }
1115 err = nr;
1116out_elf_end:
1117 return err;
1118}
1119
1120static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1121{
1122 GElf_Phdr phdr;
1123 size_t i, phdrnum;
1124 int err;
1125 u64 sz;
1126
1127 if (elf_getphdrnum(elf, &phdrnum))
1128 return -1;
1129
1130 for (i = 0; i < phdrnum; i++) {
1131 if (gelf_getphdr(elf, i, &phdr) == NULL)
1132 return -1;
1133 if (phdr.p_type != PT_LOAD)
1134 continue;
1135 if (exe) {
1136 if (!(phdr.p_flags & PF_X))
1137 continue;
1138 } else {
1139 if (!(phdr.p_flags & PF_R))
1140 continue;
1141 }
1142 sz = min(phdr.p_memsz, phdr.p_filesz);
1143 if (!sz)
1144 continue;
1145 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1146 if (err)
1147 return err;
1148 }
1149 return 0;
1150}
1151
1152int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1153 bool *is_64_bit)
1154{
1155 int err;
1156 Elf *elf;
1157
1158 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1159 if (elf == NULL)
1160 return -1;
1161
1162 if (is_64_bit)
1163 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1164
1165 err = elf_read_maps(elf, exe, mapfn, data);
1166
1167 elf_end(elf);
1168 return err;
1169}
1170
1171enum dso_type dso__type_fd(int fd)
1172{
1173 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1174 GElf_Ehdr ehdr;
1175 Elf_Kind ek;
1176 Elf *elf;
1177
1178 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1179 if (elf == NULL)
1180 goto out;
1181
1182 ek = elf_kind(elf);
1183 if (ek != ELF_K_ELF)
1184 goto out_end;
1185
1186 if (gelf_getclass(elf) == ELFCLASS64) {
1187 dso_type = DSO__TYPE_64BIT;
1188 goto out_end;
1189 }
1190
1191 if (gelf_getehdr(elf, &ehdr) == NULL)
1192 goto out_end;
1193
1194 if (ehdr.e_machine == EM_X86_64)
1195 dso_type = DSO__TYPE_X32BIT;
1196 else
1197 dso_type = DSO__TYPE_32BIT;
1198out_end:
1199 elf_end(elf);
1200out:
1201 return dso_type;
1202}
1203
1204static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1205{
1206 ssize_t r;
1207 size_t n;
1208 int err = -1;
1209 char *buf = malloc(page_size);
1210
1211 if (buf == NULL)
1212 return -1;
1213
1214 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1215 goto out;
1216
1217 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1218 goto out;
1219
1220 while (len) {
1221 n = page_size;
1222 if (len < n)
1223 n = len;
1224 /* Use read because mmap won't work on proc files */
1225 r = read(from, buf, n);
1226 if (r < 0)
1227 goto out;
1228 if (!r)
1229 break;
1230 n = r;
1231 r = write(to, buf, n);
1232 if (r < 0)
1233 goto out;
1234 if ((size_t)r != n)
1235 goto out;
1236 len -= n;
1237 }
1238
1239 err = 0;
1240out:
1241 free(buf);
1242 return err;
1243}
1244
1245struct kcore {
1246 int fd;
1247 int elfclass;
1248 Elf *elf;
1249 GElf_Ehdr ehdr;
1250};
1251
1252static int kcore__open(struct kcore *kcore, const char *filename)
1253{
1254 GElf_Ehdr *ehdr;
1255
1256 kcore->fd = open(filename, O_RDONLY);
1257 if (kcore->fd == -1)
1258 return -1;
1259
1260 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1261 if (!kcore->elf)
1262 goto out_close;
1263
1264 kcore->elfclass = gelf_getclass(kcore->elf);
1265 if (kcore->elfclass == ELFCLASSNONE)
1266 goto out_end;
1267
1268 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1269 if (!ehdr)
1270 goto out_end;
1271
1272 return 0;
1273
1274out_end:
1275 elf_end(kcore->elf);
1276out_close:
1277 close(kcore->fd);
1278 return -1;
1279}
1280
1281static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1282 bool temp)
1283{
1284 kcore->elfclass = elfclass;
1285
1286 if (temp)
1287 kcore->fd = mkstemp(filename);
1288 else
1289 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1290 if (kcore->fd == -1)
1291 return -1;
1292
1293 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1294 if (!kcore->elf)
1295 goto out_close;
1296
1297 if (!gelf_newehdr(kcore->elf, elfclass))
1298 goto out_end;
1299
1300 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1301
1302 return 0;
1303
1304out_end:
1305 elf_end(kcore->elf);
1306out_close:
1307 close(kcore->fd);
1308 unlink(filename);
1309 return -1;
1310}
1311
1312static void kcore__close(struct kcore *kcore)
1313{
1314 elf_end(kcore->elf);
1315 close(kcore->fd);
1316}
1317
1318static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1319{
1320 GElf_Ehdr *ehdr = &to->ehdr;
1321 GElf_Ehdr *kehdr = &from->ehdr;
1322
1323 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1324 ehdr->e_type = kehdr->e_type;
1325 ehdr->e_machine = kehdr->e_machine;
1326 ehdr->e_version = kehdr->e_version;
1327 ehdr->e_entry = 0;
1328 ehdr->e_shoff = 0;
1329 ehdr->e_flags = kehdr->e_flags;
1330 ehdr->e_phnum = count;
1331 ehdr->e_shentsize = 0;
1332 ehdr->e_shnum = 0;
1333 ehdr->e_shstrndx = 0;
1334
1335 if (from->elfclass == ELFCLASS32) {
1336 ehdr->e_phoff = sizeof(Elf32_Ehdr);
1337 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
1338 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1339 } else {
1340 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1341 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1342 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1343 }
1344
1345 if (!gelf_update_ehdr(to->elf, ehdr))
1346 return -1;
1347
1348 if (!gelf_newphdr(to->elf, count))
1349 return -1;
1350
1351 return 0;
1352}
1353
1354static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1355 u64 addr, u64 len)
1356{
1357 GElf_Phdr phdr = {
1358 .p_type = PT_LOAD,
1359 .p_flags = PF_R | PF_W | PF_X,
1360 .p_offset = offset,
1361 .p_vaddr = addr,
1362 .p_paddr = 0,
1363 .p_filesz = len,
1364 .p_memsz = len,
1365 .p_align = page_size,
1366 };
1367
1368 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1369 return -1;
1370
1371 return 0;
1372}
1373
1374static off_t kcore__write(struct kcore *kcore)
1375{
1376 return elf_update(kcore->elf, ELF_C_WRITE);
1377}
1378
1379struct phdr_data {
1380 off_t offset;
1381 u64 addr;
1382 u64 len;
1383};
1384
1385struct kcore_copy_info {
1386 u64 stext;
1387 u64 etext;
1388 u64 first_symbol;
1389 u64 last_symbol;
1390 u64 first_module;
1391 u64 last_module_symbol;
1392 struct phdr_data kernel_map;
1393 struct phdr_data modules_map;
1394};
1395
1396static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1397 u64 start)
1398{
1399 struct kcore_copy_info *kci = arg;
1400
1401 if (!symbol_type__is_a(type, MAP__FUNCTION))
1402 return 0;
1403
1404 if (strchr(name, '[')) {
1405 if (start > kci->last_module_symbol)
1406 kci->last_module_symbol = start;
1407 return 0;
1408 }
1409
1410 if (!kci->first_symbol || start < kci->first_symbol)
1411 kci->first_symbol = start;
1412
1413 if (!kci->last_symbol || start > kci->last_symbol)
1414 kci->last_symbol = start;
1415
1416 if (!strcmp(name, "_stext")) {
1417 kci->stext = start;
1418 return 0;
1419 }
1420
1421 if (!strcmp(name, "_etext")) {
1422 kci->etext = start;
1423 return 0;
1424 }
1425
1426 return 0;
1427}
1428
1429static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1430 const char *dir)
1431{
1432 char kallsyms_filename[PATH_MAX];
1433
1434 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1435
1436 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1437 return -1;
1438
1439 if (kallsyms__parse(kallsyms_filename, kci,
1440 kcore_copy__process_kallsyms) < 0)
1441 return -1;
1442
1443 return 0;
1444}
1445
1446static int kcore_copy__process_modules(void *arg,
1447 const char *name __maybe_unused,
1448 u64 start)
1449{
1450 struct kcore_copy_info *kci = arg;
1451
1452 if (!kci->first_module || start < kci->first_module)
1453 kci->first_module = start;
1454
1455 return 0;
1456}
1457
1458static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1459 const char *dir)
1460{
1461 char modules_filename[PATH_MAX];
1462
1463 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1464
1465 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1466 return -1;
1467
1468 if (modules__parse(modules_filename, kci,
1469 kcore_copy__process_modules) < 0)
1470 return -1;
1471
1472 return 0;
1473}
1474
1475static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1476 u64 s, u64 e)
1477{
1478 if (p->addr || s < start || s >= end)
1479 return;
1480
1481 p->addr = s;
1482 p->offset = (s - start) + pgoff;
1483 p->len = e < end ? e - s : end - s;
1484}
1485
1486static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1487{
1488 struct kcore_copy_info *kci = data;
1489 u64 end = start + len;
1490
1491 kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1492 kci->etext);
1493
1494 kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1495 kci->last_module_symbol);
1496
1497 return 0;
1498}
1499
1500static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1501{
1502 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1503 return -1;
1504
1505 return 0;
1506}
1507
1508static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1509 Elf *elf)
1510{
1511 if (kcore_copy__parse_kallsyms(kci, dir))
1512 return -1;
1513
1514 if (kcore_copy__parse_modules(kci, dir))
1515 return -1;
1516
1517 if (kci->stext)
1518 kci->stext = round_down(kci->stext, page_size);
1519 else
1520 kci->stext = round_down(kci->first_symbol, page_size);
1521
1522 if (kci->etext) {
1523 kci->etext = round_up(kci->etext, page_size);
1524 } else if (kci->last_symbol) {
1525 kci->etext = round_up(kci->last_symbol, page_size);
1526 kci->etext += page_size;
1527 }
1528
1529 kci->first_module = round_down(kci->first_module, page_size);
1530
1531 if (kci->last_module_symbol) {
1532 kci->last_module_symbol = round_up(kci->last_module_symbol,
1533 page_size);
1534 kci->last_module_symbol += page_size;
1535 }
1536
1537 if (!kci->stext || !kci->etext)
1538 return -1;
1539
1540 if (kci->first_module && !kci->last_module_symbol)
1541 return -1;
1542
1543 return kcore_copy__read_maps(kci, elf);
1544}
1545
1546static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1547 const char *name)
1548{
1549 char from_filename[PATH_MAX];
1550 char to_filename[PATH_MAX];
1551
1552 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1553 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1554
1555 return copyfile_mode(from_filename, to_filename, 0400);
1556}
1557
1558static int kcore_copy__unlink(const char *dir, const char *name)
1559{
1560 char filename[PATH_MAX];
1561
1562 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1563
1564 return unlink(filename);
1565}
1566
1567static int kcore_copy__compare_fds(int from, int to)
1568{
1569 char *buf_from;
1570 char *buf_to;
1571 ssize_t ret;
1572 size_t len;
1573 int err = -1;
1574
1575 buf_from = malloc(page_size);
1576 buf_to = malloc(page_size);
1577 if (!buf_from || !buf_to)
1578 goto out;
1579
1580 while (1) {
1581 /* Use read because mmap won't work on proc files */
1582 ret = read(from, buf_from, page_size);
1583 if (ret < 0)
1584 goto out;
1585
1586 if (!ret)
1587 break;
1588
1589 len = ret;
1590
1591 if (readn(to, buf_to, len) != (int)len)
1592 goto out;
1593
1594 if (memcmp(buf_from, buf_to, len))
1595 goto out;
1596 }
1597
1598 err = 0;
1599out:
1600 free(buf_to);
1601 free(buf_from);
1602 return err;
1603}
1604
1605static int kcore_copy__compare_files(const char *from_filename,
1606 const char *to_filename)
1607{
1608 int from, to, err = -1;
1609
1610 from = open(from_filename, O_RDONLY);
1611 if (from < 0)
1612 return -1;
1613
1614 to = open(to_filename, O_RDONLY);
1615 if (to < 0)
1616 goto out_close_from;
1617
1618 err = kcore_copy__compare_fds(from, to);
1619
1620 close(to);
1621out_close_from:
1622 close(from);
1623 return err;
1624}
1625
1626static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1627 const char *name)
1628{
1629 char from_filename[PATH_MAX];
1630 char to_filename[PATH_MAX];
1631
1632 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1633 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1634
1635 return kcore_copy__compare_files(from_filename, to_filename);
1636}
1637
1638/**
1639 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1640 * @from_dir: from directory
1641 * @to_dir: to directory
1642 *
1643 * This function copies kallsyms, modules and kcore files from one directory to
1644 * another. kallsyms and modules are copied entirely. Only code segments are
1645 * copied from kcore. It is assumed that two segments suffice: one for the
1646 * kernel proper and one for all the modules. The code segments are determined
1647 * from kallsyms and modules files. The kernel map starts at _stext or the
1648 * lowest function symbol, and ends at _etext or the highest function symbol.
1649 * The module map starts at the lowest module address and ends at the highest
1650 * module symbol. Start addresses are rounded down to the nearest page. End
1651 * addresses are rounded up to the nearest page. An extra page is added to the
1652 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1653 * symbol too. Because it contains only code sections, the resulting kcore is
1654 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1655 * is not the same for the kernel map and the modules map. That happens because
1656 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1657 * kallsyms and modules files are compared with their copies to check that
1658 * modules have not been loaded or unloaded while the copies were taking place.
1659 *
1660 * Return: %0 on success, %-1 on failure.
1661 */
1662int kcore_copy(const char *from_dir, const char *to_dir)
1663{
1664 struct kcore kcore;
1665 struct kcore extract;
1666 size_t count = 2;
1667 int idx = 0, err = -1;
1668 off_t offset = page_size, sz, modules_offset = 0;
1669 struct kcore_copy_info kci = { .stext = 0, };
1670 char kcore_filename[PATH_MAX];
1671 char extract_filename[PATH_MAX];
1672
1673 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1674 return -1;
1675
1676 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1677 goto out_unlink_kallsyms;
1678
1679 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1680 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1681
1682 if (kcore__open(&kcore, kcore_filename))
1683 goto out_unlink_modules;
1684
1685 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1686 goto out_kcore_close;
1687
1688 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1689 goto out_kcore_close;
1690
1691 if (!kci.modules_map.addr)
1692 count -= 1;
1693
1694 if (kcore__copy_hdr(&kcore, &extract, count))
1695 goto out_extract_close;
1696
1697 if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1698 kci.kernel_map.len))
1699 goto out_extract_close;
1700
1701 if (kci.modules_map.addr) {
1702 modules_offset = offset + kci.kernel_map.len;
1703 if (kcore__add_phdr(&extract, idx, modules_offset,
1704 kci.modules_map.addr, kci.modules_map.len))
1705 goto out_extract_close;
1706 }
1707
1708 sz = kcore__write(&extract);
1709 if (sz < 0 || sz > offset)
1710 goto out_extract_close;
1711
1712 if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1713 kci.kernel_map.len))
1714 goto out_extract_close;
1715
1716 if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1717 extract.fd, modules_offset,
1718 kci.modules_map.len))
1719 goto out_extract_close;
1720
1721 if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1722 goto out_extract_close;
1723
1724 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1725 goto out_extract_close;
1726
1727 err = 0;
1728
1729out_extract_close:
1730 kcore__close(&extract);
1731 if (err)
1732 unlink(extract_filename);
1733out_kcore_close:
1734 kcore__close(&kcore);
1735out_unlink_modules:
1736 if (err)
1737 kcore_copy__unlink(to_dir, "modules");
1738out_unlink_kallsyms:
1739 if (err)
1740 kcore_copy__unlink(to_dir, "kallsyms");
1741
1742 return err;
1743}
1744
1745int kcore_extract__create(struct kcore_extract *kce)
1746{
1747 struct kcore kcore;
1748 struct kcore extract;
1749 size_t count = 1;
1750 int idx = 0, err = -1;
1751 off_t offset = page_size, sz;
1752
1753 if (kcore__open(&kcore, kce->kcore_filename))
1754 return -1;
1755
1756 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1757 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1758 goto out_kcore_close;
1759
1760 if (kcore__copy_hdr(&kcore, &extract, count))
1761 goto out_extract_close;
1762
1763 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1764 goto out_extract_close;
1765
1766 sz = kcore__write(&extract);
1767 if (sz < 0 || sz > offset)
1768 goto out_extract_close;
1769
1770 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1771 goto out_extract_close;
1772
1773 err = 0;
1774
1775out_extract_close:
1776 kcore__close(&extract);
1777 if (err)
1778 unlink(kce->extract_filename);
1779out_kcore_close:
1780 kcore__close(&kcore);
1781
1782 return err;
1783}
1784
1785void kcore_extract__delete(struct kcore_extract *kce)
1786{
1787 unlink(kce->extract_filename);
1788}
1789
1790void symbol__elf_init(void)
1791{
1792 elf_version(EV_CURRENT);
1793}
1// SPDX-License-Identifier: GPL-2.0
2#include <fcntl.h>
3#include <stdio.h>
4#include <errno.h>
5#include <stdlib.h>
6#include <string.h>
7#include <unistd.h>
8#include <inttypes.h>
9
10#include "dso.h"
11#include "map.h"
12#include "maps.h"
13#include "symbol.h"
14#include "symsrc.h"
15#include "demangle-cxx.h"
16#include "demangle-ocaml.h"
17#include "demangle-java.h"
18#include "demangle-rust.h"
19#include "machine.h"
20#include "vdso.h"
21#include "debug.h"
22#include "util/copyfile.h"
23#include <linux/ctype.h>
24#include <linux/kernel.h>
25#include <linux/zalloc.h>
26#include <linux/string.h>
27#include <symbol/kallsyms.h>
28#include <internal/lib.h>
29
30#ifdef HAVE_LIBBFD_SUPPORT
31#define PACKAGE 'perf'
32#include <bfd.h>
33#endif
34
35#if defined(HAVE_LIBBFD_SUPPORT) || defined(HAVE_CPLUS_DEMANGLE_SUPPORT)
36#ifndef DMGL_PARAMS
37#define DMGL_PARAMS (1 << 0) /* Include function args */
38#define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
39#endif
40#endif
41
42#ifndef EM_AARCH64
43#define EM_AARCH64 183 /* ARM 64 bit */
44#endif
45
46#ifndef EM_LOONGARCH
47#define EM_LOONGARCH 258
48#endif
49
50#ifndef ELF32_ST_VISIBILITY
51#define ELF32_ST_VISIBILITY(o) ((o) & 0x03)
52#endif
53
54/* For ELF64 the definitions are the same. */
55#ifndef ELF64_ST_VISIBILITY
56#define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o)
57#endif
58
59/* How to extract information held in the st_other field. */
60#ifndef GELF_ST_VISIBILITY
61#define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
62#endif
63
64typedef Elf64_Nhdr GElf_Nhdr;
65
66
67#ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
68static int elf_getphdrnum(Elf *elf, size_t *dst)
69{
70 GElf_Ehdr gehdr;
71 GElf_Ehdr *ehdr;
72
73 ehdr = gelf_getehdr(elf, &gehdr);
74 if (!ehdr)
75 return -1;
76
77 *dst = ehdr->e_phnum;
78
79 return 0;
80}
81#endif
82
83#ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
84static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
85{
86 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
87 return -1;
88}
89#endif
90
91#ifndef NT_GNU_BUILD_ID
92#define NT_GNU_BUILD_ID 3
93#endif
94
95/**
96 * elf_symtab__for_each_symbol - iterate thru all the symbols
97 *
98 * @syms: struct elf_symtab instance to iterate
99 * @idx: uint32_t idx
100 * @sym: GElf_Sym iterator
101 */
102#define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
103 for (idx = 0, gelf_getsym(syms, idx, &sym);\
104 idx < nr_syms; \
105 idx++, gelf_getsym(syms, idx, &sym))
106
107static inline uint8_t elf_sym__type(const GElf_Sym *sym)
108{
109 return GELF_ST_TYPE(sym->st_info);
110}
111
112static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
113{
114 return GELF_ST_VISIBILITY(sym->st_other);
115}
116
117#ifndef STT_GNU_IFUNC
118#define STT_GNU_IFUNC 10
119#endif
120
121static inline int elf_sym__is_function(const GElf_Sym *sym)
122{
123 return (elf_sym__type(sym) == STT_FUNC ||
124 elf_sym__type(sym) == STT_GNU_IFUNC) &&
125 sym->st_name != 0 &&
126 sym->st_shndx != SHN_UNDEF;
127}
128
129static inline bool elf_sym__is_object(const GElf_Sym *sym)
130{
131 return elf_sym__type(sym) == STT_OBJECT &&
132 sym->st_name != 0 &&
133 sym->st_shndx != SHN_UNDEF;
134}
135
136static inline int elf_sym__is_label(const GElf_Sym *sym)
137{
138 return elf_sym__type(sym) == STT_NOTYPE &&
139 sym->st_name != 0 &&
140 sym->st_shndx != SHN_UNDEF &&
141 sym->st_shndx != SHN_ABS &&
142 elf_sym__visibility(sym) != STV_HIDDEN &&
143 elf_sym__visibility(sym) != STV_INTERNAL;
144}
145
146static bool elf_sym__filter(GElf_Sym *sym)
147{
148 return elf_sym__is_function(sym) || elf_sym__is_object(sym);
149}
150
151static inline const char *elf_sym__name(const GElf_Sym *sym,
152 const Elf_Data *symstrs)
153{
154 return symstrs->d_buf + sym->st_name;
155}
156
157static inline const char *elf_sec__name(const GElf_Shdr *shdr,
158 const Elf_Data *secstrs)
159{
160 return secstrs->d_buf + shdr->sh_name;
161}
162
163static inline int elf_sec__is_text(const GElf_Shdr *shdr,
164 const Elf_Data *secstrs)
165{
166 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
167}
168
169static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
170 const Elf_Data *secstrs)
171{
172 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
173}
174
175static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
176{
177 return elf_sec__is_text(shdr, secstrs) ||
178 elf_sec__is_data(shdr, secstrs);
179}
180
181static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
182{
183 Elf_Scn *sec = NULL;
184 GElf_Shdr shdr;
185 size_t cnt = 1;
186
187 while ((sec = elf_nextscn(elf, sec)) != NULL) {
188 gelf_getshdr(sec, &shdr);
189
190 if ((addr >= shdr.sh_addr) &&
191 (addr < (shdr.sh_addr + shdr.sh_size)))
192 return cnt;
193
194 ++cnt;
195 }
196
197 return -1;
198}
199
200Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
201 GElf_Shdr *shp, const char *name, size_t *idx)
202{
203 Elf_Scn *sec = NULL;
204 size_t cnt = 1;
205
206 /* ELF is corrupted/truncated, avoid calling elf_strptr. */
207 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
208 return NULL;
209
210 while ((sec = elf_nextscn(elf, sec)) != NULL) {
211 char *str;
212
213 gelf_getshdr(sec, shp);
214 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
215 if (str && !strcmp(name, str)) {
216 if (idx)
217 *idx = cnt;
218 return sec;
219 }
220 ++cnt;
221 }
222
223 return NULL;
224}
225
226bool filename__has_section(const char *filename, const char *sec)
227{
228 int fd;
229 Elf *elf;
230 GElf_Ehdr ehdr;
231 GElf_Shdr shdr;
232 bool found = false;
233
234 fd = open(filename, O_RDONLY);
235 if (fd < 0)
236 return false;
237
238 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
239 if (elf == NULL)
240 goto out;
241
242 if (gelf_getehdr(elf, &ehdr) == NULL)
243 goto elf_out;
244
245 found = !!elf_section_by_name(elf, &ehdr, &shdr, sec, NULL);
246
247elf_out:
248 elf_end(elf);
249out:
250 close(fd);
251 return found;
252}
253
254static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr)
255{
256 size_t i, phdrnum;
257 u64 sz;
258
259 if (elf_getphdrnum(elf, &phdrnum))
260 return -1;
261
262 for (i = 0; i < phdrnum; i++) {
263 if (gelf_getphdr(elf, i, phdr) == NULL)
264 return -1;
265
266 if (phdr->p_type != PT_LOAD)
267 continue;
268
269 sz = max(phdr->p_memsz, phdr->p_filesz);
270 if (!sz)
271 continue;
272
273 if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz))
274 return 0;
275 }
276
277 /* Not found any valid program header */
278 return -1;
279}
280
281static bool want_demangle(bool is_kernel_sym)
282{
283 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
284}
285
286/*
287 * Demangle C++ function signature, typically replaced by demangle-cxx.cpp
288 * version.
289 */
290__weak char *cxx_demangle_sym(const char *str __maybe_unused, bool params __maybe_unused,
291 bool modifiers __maybe_unused)
292{
293#ifdef HAVE_LIBBFD_SUPPORT
294 int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0);
295
296 return bfd_demangle(NULL, str, flags);
297#elif defined(HAVE_CPLUS_DEMANGLE_SUPPORT)
298 int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0);
299
300 return cplus_demangle(str, flags);
301#else
302 return NULL;
303#endif
304}
305
306static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
307{
308 char *demangled = NULL;
309
310 /*
311 * We need to figure out if the object was created from C++ sources
312 * DWARF DW_compile_unit has this, but we don't always have access
313 * to it...
314 */
315 if (!want_demangle(dso->kernel || kmodule))
316 return demangled;
317
318 demangled = cxx_demangle_sym(elf_name, verbose > 0, verbose > 0);
319 if (demangled == NULL) {
320 demangled = ocaml_demangle_sym(elf_name);
321 if (demangled == NULL) {
322 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
323 }
324 }
325 else if (rust_is_mangled(demangled))
326 /*
327 * Input to Rust demangling is the BFD-demangled
328 * name which it Rust-demangles in place.
329 */
330 rust_demangle_sym(demangled);
331
332 return demangled;
333}
334
335struct rel_info {
336 u32 nr_entries;
337 u32 *sorted;
338 bool is_rela;
339 Elf_Data *reldata;
340 GElf_Rela rela;
341 GElf_Rel rel;
342};
343
344static u32 get_rel_symidx(struct rel_info *ri, u32 idx)
345{
346 idx = ri->sorted ? ri->sorted[idx] : idx;
347 if (ri->is_rela) {
348 gelf_getrela(ri->reldata, idx, &ri->rela);
349 return GELF_R_SYM(ri->rela.r_info);
350 }
351 gelf_getrel(ri->reldata, idx, &ri->rel);
352 return GELF_R_SYM(ri->rel.r_info);
353}
354
355static u64 get_rel_offset(struct rel_info *ri, u32 x)
356{
357 if (ri->is_rela) {
358 GElf_Rela rela;
359
360 gelf_getrela(ri->reldata, x, &rela);
361 return rela.r_offset;
362 } else {
363 GElf_Rel rel;
364
365 gelf_getrel(ri->reldata, x, &rel);
366 return rel.r_offset;
367 }
368}
369
370static int rel_cmp(const void *a, const void *b, void *r)
371{
372 struct rel_info *ri = r;
373 u64 a_offset = get_rel_offset(ri, *(const u32 *)a);
374 u64 b_offset = get_rel_offset(ri, *(const u32 *)b);
375
376 return a_offset < b_offset ? -1 : (a_offset > b_offset ? 1 : 0);
377}
378
379static int sort_rel(struct rel_info *ri)
380{
381 size_t sz = sizeof(ri->sorted[0]);
382 u32 i;
383
384 ri->sorted = calloc(ri->nr_entries, sz);
385 if (!ri->sorted)
386 return -1;
387 for (i = 0; i < ri->nr_entries; i++)
388 ri->sorted[i] = i;
389 qsort_r(ri->sorted, ri->nr_entries, sz, rel_cmp, ri);
390 return 0;
391}
392
393/*
394 * For x86_64, the GNU linker is putting IFUNC information in the relocation
395 * addend.
396 */
397static bool addend_may_be_ifunc(GElf_Ehdr *ehdr, struct rel_info *ri)
398{
399 return ehdr->e_machine == EM_X86_64 && ri->is_rela &&
400 GELF_R_TYPE(ri->rela.r_info) == R_X86_64_IRELATIVE;
401}
402
403static bool get_ifunc_name(Elf *elf, struct dso *dso, GElf_Ehdr *ehdr,
404 struct rel_info *ri, char *buf, size_t buf_sz)
405{
406 u64 addr = ri->rela.r_addend;
407 struct symbol *sym;
408 GElf_Phdr phdr;
409
410 if (!addend_may_be_ifunc(ehdr, ri))
411 return false;
412
413 if (elf_read_program_header(elf, addr, &phdr))
414 return false;
415
416 addr -= phdr.p_vaddr - phdr.p_offset;
417
418 sym = dso__find_symbol_nocache(dso, addr);
419
420 /* Expecting the address to be an IFUNC or IFUNC alias */
421 if (!sym || sym->start != addr || (sym->type != STT_GNU_IFUNC && !sym->ifunc_alias))
422 return false;
423
424 snprintf(buf, buf_sz, "%s@plt", sym->name);
425
426 return true;
427}
428
429static void exit_rel(struct rel_info *ri)
430{
431 zfree(&ri->sorted);
432}
433
434static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,
435 u64 *plt_header_size, u64 *plt_entry_size)
436{
437 switch (ehdr->e_machine) {
438 case EM_ARM:
439 *plt_header_size = 20;
440 *plt_entry_size = 12;
441 return true;
442 case EM_AARCH64:
443 *plt_header_size = 32;
444 *plt_entry_size = 16;
445 return true;
446 case EM_LOONGARCH:
447 *plt_header_size = 32;
448 *plt_entry_size = 16;
449 return true;
450 case EM_SPARC:
451 *plt_header_size = 48;
452 *plt_entry_size = 12;
453 return true;
454 case EM_SPARCV9:
455 *plt_header_size = 128;
456 *plt_entry_size = 32;
457 return true;
458 case EM_386:
459 case EM_X86_64:
460 *plt_entry_size = shdr_plt->sh_entsize;
461 /* Size is 8 or 16, if not, assume alignment indicates size */
462 if (*plt_entry_size != 8 && *plt_entry_size != 16)
463 *plt_entry_size = shdr_plt->sh_addralign == 8 ? 8 : 16;
464 *plt_header_size = *plt_entry_size;
465 break;
466 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
467 *plt_header_size = shdr_plt->sh_entsize;
468 *plt_entry_size = shdr_plt->sh_entsize;
469 break;
470 }
471 if (*plt_entry_size)
472 return true;
473 pr_debug("Missing PLT entry size for %s\n", dso->long_name);
474 return false;
475}
476
477static bool machine_is_x86(GElf_Half e_machine)
478{
479 return e_machine == EM_386 || e_machine == EM_X86_64;
480}
481
482struct rela_dyn {
483 GElf_Addr offset;
484 u32 sym_idx;
485};
486
487struct rela_dyn_info {
488 struct dso *dso;
489 Elf_Data *plt_got_data;
490 u32 nr_entries;
491 struct rela_dyn *sorted;
492 Elf_Data *dynsym_data;
493 Elf_Data *dynstr_data;
494 Elf_Data *rela_dyn_data;
495};
496
497static void exit_rela_dyn(struct rela_dyn_info *di)
498{
499 zfree(&di->sorted);
500}
501
502static int cmp_offset(const void *a, const void *b)
503{
504 const struct rela_dyn *va = a;
505 const struct rela_dyn *vb = b;
506
507 return va->offset < vb->offset ? -1 : (va->offset > vb->offset ? 1 : 0);
508}
509
510static int sort_rela_dyn(struct rela_dyn_info *di)
511{
512 u32 i, n;
513
514 di->sorted = calloc(di->nr_entries, sizeof(di->sorted[0]));
515 if (!di->sorted)
516 return -1;
517
518 /* Get data for sorting: the offset and symbol index */
519 for (i = 0, n = 0; i < di->nr_entries; i++) {
520 GElf_Rela rela;
521 u32 sym_idx;
522
523 gelf_getrela(di->rela_dyn_data, i, &rela);
524 sym_idx = GELF_R_SYM(rela.r_info);
525 if (sym_idx) {
526 di->sorted[n].sym_idx = sym_idx;
527 di->sorted[n].offset = rela.r_offset;
528 n += 1;
529 }
530 }
531
532 /* Sort by offset */
533 di->nr_entries = n;
534 qsort(di->sorted, n, sizeof(di->sorted[0]), cmp_offset);
535
536 return 0;
537}
538
539static void get_rela_dyn_info(Elf *elf, GElf_Ehdr *ehdr, struct rela_dyn_info *di, Elf_Scn *scn)
540{
541 GElf_Shdr rela_dyn_shdr;
542 GElf_Shdr shdr;
543
544 di->plt_got_data = elf_getdata(scn, NULL);
545
546 scn = elf_section_by_name(elf, ehdr, &rela_dyn_shdr, ".rela.dyn", NULL);
547 if (!scn || !rela_dyn_shdr.sh_link || !rela_dyn_shdr.sh_entsize)
548 return;
549
550 di->nr_entries = rela_dyn_shdr.sh_size / rela_dyn_shdr.sh_entsize;
551 di->rela_dyn_data = elf_getdata(scn, NULL);
552
553 scn = elf_getscn(elf, rela_dyn_shdr.sh_link);
554 if (!scn || !gelf_getshdr(scn, &shdr) || !shdr.sh_link)
555 return;
556
557 di->dynsym_data = elf_getdata(scn, NULL);
558 di->dynstr_data = elf_getdata(elf_getscn(elf, shdr.sh_link), NULL);
559
560 if (!di->plt_got_data || !di->dynstr_data || !di->dynsym_data || !di->rela_dyn_data)
561 return;
562
563 /* Sort into offset order */
564 sort_rela_dyn(di);
565}
566
567/* Get instruction displacement from a plt entry for x86_64 */
568static u32 get_x86_64_plt_disp(const u8 *p)
569{
570 u8 endbr64[] = {0xf3, 0x0f, 0x1e, 0xfa};
571 int n = 0;
572
573 /* Skip endbr64 */
574 if (!memcmp(p, endbr64, sizeof(endbr64)))
575 n += sizeof(endbr64);
576 /* Skip bnd prefix */
577 if (p[n] == 0xf2)
578 n += 1;
579 /* jmp with 4-byte displacement */
580 if (p[n] == 0xff && p[n + 1] == 0x25) {
581 u32 disp;
582
583 n += 2;
584 /* Also add offset from start of entry to end of instruction */
585 memcpy(&disp, p + n, sizeof(disp));
586 return n + 4 + le32toh(disp);
587 }
588 return 0;
589}
590
591static bool get_plt_got_name(GElf_Shdr *shdr, size_t i,
592 struct rela_dyn_info *di,
593 char *buf, size_t buf_sz)
594{
595 struct rela_dyn vi, *vr;
596 const char *sym_name;
597 char *demangled;
598 GElf_Sym sym;
599 bool result;
600 u32 disp;
601
602 if (!di->sorted)
603 return false;
604
605 disp = get_x86_64_plt_disp(di->plt_got_data->d_buf + i);
606 if (!disp)
607 return false;
608
609 /* Compute target offset of the .plt.got entry */
610 vi.offset = shdr->sh_offset + di->plt_got_data->d_off + i + disp;
611
612 /* Find that offset in .rela.dyn (sorted by offset) */
613 vr = bsearch(&vi, di->sorted, di->nr_entries, sizeof(di->sorted[0]), cmp_offset);
614 if (!vr)
615 return false;
616
617 /* Get the associated symbol */
618 gelf_getsym(di->dynsym_data, vr->sym_idx, &sym);
619 sym_name = elf_sym__name(&sym, di->dynstr_data);
620 demangled = demangle_sym(di->dso, 0, sym_name);
621 if (demangled != NULL)
622 sym_name = demangled;
623
624 snprintf(buf, buf_sz, "%s@plt", sym_name);
625
626 result = *sym_name;
627
628 free(demangled);
629
630 return result;
631}
632
633static int dso__synthesize_plt_got_symbols(struct dso *dso, Elf *elf,
634 GElf_Ehdr *ehdr,
635 char *buf, size_t buf_sz)
636{
637 struct rela_dyn_info di = { .dso = dso };
638 struct symbol *sym;
639 GElf_Shdr shdr;
640 Elf_Scn *scn;
641 int err = -1;
642 size_t i;
643
644 scn = elf_section_by_name(elf, ehdr, &shdr, ".plt.got", NULL);
645 if (!scn || !shdr.sh_entsize)
646 return 0;
647
648 if (ehdr->e_machine == EM_X86_64)
649 get_rela_dyn_info(elf, ehdr, &di, scn);
650
651 for (i = 0; i < shdr.sh_size; i += shdr.sh_entsize) {
652 if (!get_plt_got_name(&shdr, i, &di, buf, buf_sz))
653 snprintf(buf, buf_sz, "offset_%#" PRIx64 "@plt", (u64)shdr.sh_offset + i);
654 sym = symbol__new(shdr.sh_offset + i, shdr.sh_entsize, STB_GLOBAL, STT_FUNC, buf);
655 if (!sym)
656 goto out;
657 symbols__insert(&dso->symbols, sym);
658 }
659 err = 0;
660out:
661 exit_rela_dyn(&di);
662 return err;
663}
664
665/*
666 * We need to check if we have a .dynsym, so that we can handle the
667 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
668 * .dynsym or .symtab).
669 * And always look at the original dso, not at debuginfo packages, that
670 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
671 */
672int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
673{
674 uint32_t idx;
675 GElf_Sym sym;
676 u64 plt_offset, plt_header_size, plt_entry_size;
677 GElf_Shdr shdr_plt, plt_sec_shdr;
678 struct symbol *f, *plt_sym;
679 GElf_Shdr shdr_rel_plt, shdr_dynsym;
680 Elf_Data *syms, *symstrs;
681 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
682 GElf_Ehdr ehdr;
683 char sympltname[1024];
684 Elf *elf;
685 int nr = 0, err = -1;
686 struct rel_info ri = { .is_rela = false };
687 bool lazy_plt;
688
689 elf = ss->elf;
690 ehdr = ss->ehdr;
691
692 if (!elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL))
693 return 0;
694
695 /*
696 * A symbol from a previous section (e.g. .init) can have been expanded
697 * by symbols__fixup_end() to overlap .plt. Truncate it before adding
698 * a symbol for .plt header.
699 */
700 f = dso__find_symbol_nocache(dso, shdr_plt.sh_offset);
701 if (f && f->start < shdr_plt.sh_offset && f->end > shdr_plt.sh_offset)
702 f->end = shdr_plt.sh_offset;
703
704 if (!get_plt_sizes(dso, &ehdr, &shdr_plt, &plt_header_size, &plt_entry_size))
705 return 0;
706
707 /* Add a symbol for .plt header */
708 plt_sym = symbol__new(shdr_plt.sh_offset, plt_header_size, STB_GLOBAL, STT_FUNC, ".plt");
709 if (!plt_sym)
710 goto out_elf_end;
711 symbols__insert(&dso->symbols, plt_sym);
712
713 /* Only x86 has .plt.got */
714 if (machine_is_x86(ehdr.e_machine) &&
715 dso__synthesize_plt_got_symbols(dso, elf, &ehdr, sympltname, sizeof(sympltname)))
716 goto out_elf_end;
717
718 /* Only x86 has .plt.sec */
719 if (machine_is_x86(ehdr.e_machine) &&
720 elf_section_by_name(elf, &ehdr, &plt_sec_shdr, ".plt.sec", NULL)) {
721 if (!get_plt_sizes(dso, &ehdr, &plt_sec_shdr, &plt_header_size, &plt_entry_size))
722 return 0;
723 /* Extend .plt symbol to entire .plt */
724 plt_sym->end = plt_sym->start + shdr_plt.sh_size;
725 /* Use .plt.sec offset */
726 plt_offset = plt_sec_shdr.sh_offset;
727 lazy_plt = false;
728 } else {
729 plt_offset = shdr_plt.sh_offset;
730 lazy_plt = true;
731 }
732
733 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
734 ".rela.plt", NULL);
735 if (scn_plt_rel == NULL) {
736 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
737 ".rel.plt", NULL);
738 if (scn_plt_rel == NULL)
739 return 0;
740 }
741
742 if (shdr_rel_plt.sh_type != SHT_RELA &&
743 shdr_rel_plt.sh_type != SHT_REL)
744 return 0;
745
746 if (!shdr_rel_plt.sh_link)
747 return 0;
748
749 if (shdr_rel_plt.sh_link == ss->dynsym_idx) {
750 scn_dynsym = ss->dynsym;
751 shdr_dynsym = ss->dynshdr;
752 } else if (shdr_rel_plt.sh_link == ss->symtab_idx) {
753 /*
754 * A static executable can have a .plt due to IFUNCs, in which
755 * case .symtab is used not .dynsym.
756 */
757 scn_dynsym = ss->symtab;
758 shdr_dynsym = ss->symshdr;
759 } else {
760 goto out_elf_end;
761 }
762
763 if (!scn_dynsym)
764 return 0;
765
766 /*
767 * Fetch the relocation section to find the idxes to the GOT
768 * and the symbols in the .dynsym they refer to.
769 */
770 ri.reldata = elf_getdata(scn_plt_rel, NULL);
771 if (!ri.reldata)
772 goto out_elf_end;
773
774 syms = elf_getdata(scn_dynsym, NULL);
775 if (syms == NULL)
776 goto out_elf_end;
777
778 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
779 if (scn_symstrs == NULL)
780 goto out_elf_end;
781
782 symstrs = elf_getdata(scn_symstrs, NULL);
783 if (symstrs == NULL)
784 goto out_elf_end;
785
786 if (symstrs->d_size == 0)
787 goto out_elf_end;
788
789 ri.nr_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
790
791 ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA;
792
793 if (lazy_plt) {
794 /*
795 * Assume a .plt with the same number of entries as the number
796 * of relocation entries is not lazy and does not have a header.
797 */
798 if (ri.nr_entries * plt_entry_size == shdr_plt.sh_size)
799 dso__delete_symbol(dso, plt_sym);
800 else
801 plt_offset += plt_header_size;
802 }
803
804 /*
805 * x86 doesn't insert IFUNC relocations in .plt order, so sort to get
806 * back in order.
807 */
808 if (machine_is_x86(ehdr.e_machine) && sort_rel(&ri))
809 goto out_elf_end;
810
811 for (idx = 0; idx < ri.nr_entries; idx++) {
812 const char *elf_name = NULL;
813 char *demangled = NULL;
814
815 gelf_getsym(syms, get_rel_symidx(&ri, idx), &sym);
816
817 elf_name = elf_sym__name(&sym, symstrs);
818 demangled = demangle_sym(dso, 0, elf_name);
819 if (demangled)
820 elf_name = demangled;
821 if (*elf_name)
822 snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name);
823 else if (!get_ifunc_name(elf, dso, &ehdr, &ri, sympltname, sizeof(sympltname)))
824 snprintf(sympltname, sizeof(sympltname),
825 "offset_%#" PRIx64 "@plt", plt_offset);
826 free(demangled);
827
828 f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname);
829 if (!f)
830 goto out_elf_end;
831
832 plt_offset += plt_entry_size;
833 symbols__insert(&dso->symbols, f);
834 ++nr;
835 }
836
837 err = 0;
838out_elf_end:
839 exit_rel(&ri);
840 if (err == 0)
841 return nr;
842 pr_debug("%s: problems reading %s PLT info.\n",
843 __func__, dso->long_name);
844 return 0;
845}
846
847char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
848{
849 return demangle_sym(dso, kmodule, elf_name);
850}
851
852/*
853 * Align offset to 4 bytes as needed for note name and descriptor data.
854 */
855#define NOTE_ALIGN(n) (((n) + 3) & -4U)
856
857static int elf_read_build_id(Elf *elf, void *bf, size_t size)
858{
859 int err = -1;
860 GElf_Ehdr ehdr;
861 GElf_Shdr shdr;
862 Elf_Data *data;
863 Elf_Scn *sec;
864 Elf_Kind ek;
865 void *ptr;
866
867 if (size < BUILD_ID_SIZE)
868 goto out;
869
870 ek = elf_kind(elf);
871 if (ek != ELF_K_ELF)
872 goto out;
873
874 if (gelf_getehdr(elf, &ehdr) == NULL) {
875 pr_err("%s: cannot get elf header.\n", __func__);
876 goto out;
877 }
878
879 /*
880 * Check following sections for notes:
881 * '.note.gnu.build-id'
882 * '.notes'
883 * '.note' (VDSO specific)
884 */
885 do {
886 sec = elf_section_by_name(elf, &ehdr, &shdr,
887 ".note.gnu.build-id", NULL);
888 if (sec)
889 break;
890
891 sec = elf_section_by_name(elf, &ehdr, &shdr,
892 ".notes", NULL);
893 if (sec)
894 break;
895
896 sec = elf_section_by_name(elf, &ehdr, &shdr,
897 ".note", NULL);
898 if (sec)
899 break;
900
901 return err;
902
903 } while (0);
904
905 data = elf_getdata(sec, NULL);
906 if (data == NULL)
907 goto out;
908
909 ptr = data->d_buf;
910 while (ptr < (data->d_buf + data->d_size)) {
911 GElf_Nhdr *nhdr = ptr;
912 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
913 descsz = NOTE_ALIGN(nhdr->n_descsz);
914 const char *name;
915
916 ptr += sizeof(*nhdr);
917 name = ptr;
918 ptr += namesz;
919 if (nhdr->n_type == NT_GNU_BUILD_ID &&
920 nhdr->n_namesz == sizeof("GNU")) {
921 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
922 size_t sz = min(size, descsz);
923 memcpy(bf, ptr, sz);
924 memset(bf + sz, 0, size - sz);
925 err = sz;
926 break;
927 }
928 }
929 ptr += descsz;
930 }
931
932out:
933 return err;
934}
935
936#ifdef HAVE_LIBBFD_BUILDID_SUPPORT
937
938static int read_build_id(const char *filename, struct build_id *bid)
939{
940 size_t size = sizeof(bid->data);
941 int err = -1;
942 bfd *abfd;
943
944 abfd = bfd_openr(filename, NULL);
945 if (!abfd)
946 return -1;
947
948 if (!bfd_check_format(abfd, bfd_object)) {
949 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
950 goto out_close;
951 }
952
953 if (!abfd->build_id || abfd->build_id->size > size)
954 goto out_close;
955
956 memcpy(bid->data, abfd->build_id->data, abfd->build_id->size);
957 memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size);
958 err = bid->size = abfd->build_id->size;
959
960out_close:
961 bfd_close(abfd);
962 return err;
963}
964
965#else // HAVE_LIBBFD_BUILDID_SUPPORT
966
967static int read_build_id(const char *filename, struct build_id *bid)
968{
969 size_t size = sizeof(bid->data);
970 int fd, err = -1;
971 Elf *elf;
972
973 if (size < BUILD_ID_SIZE)
974 goto out;
975
976 fd = open(filename, O_RDONLY);
977 if (fd < 0)
978 goto out;
979
980 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
981 if (elf == NULL) {
982 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
983 goto out_close;
984 }
985
986 err = elf_read_build_id(elf, bid->data, size);
987 if (err > 0)
988 bid->size = err;
989
990 elf_end(elf);
991out_close:
992 close(fd);
993out:
994 return err;
995}
996
997#endif // HAVE_LIBBFD_BUILDID_SUPPORT
998
999int filename__read_build_id(const char *filename, struct build_id *bid)
1000{
1001 struct kmod_path m = { .name = NULL, };
1002 char path[PATH_MAX];
1003 int err;
1004
1005 if (!filename)
1006 return -EFAULT;
1007
1008 err = kmod_path__parse(&m, filename);
1009 if (err)
1010 return -1;
1011
1012 if (m.comp) {
1013 int error = 0, fd;
1014
1015 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
1016 if (fd < 0) {
1017 pr_debug("Failed to decompress (error %d) %s\n",
1018 error, filename);
1019 return -1;
1020 }
1021 close(fd);
1022 filename = path;
1023 }
1024
1025 err = read_build_id(filename, bid);
1026
1027 if (m.comp)
1028 unlink(filename);
1029 return err;
1030}
1031
1032int sysfs__read_build_id(const char *filename, struct build_id *bid)
1033{
1034 size_t size = sizeof(bid->data);
1035 int fd, err = -1;
1036
1037 fd = open(filename, O_RDONLY);
1038 if (fd < 0)
1039 goto out;
1040
1041 while (1) {
1042 char bf[BUFSIZ];
1043 GElf_Nhdr nhdr;
1044 size_t namesz, descsz;
1045
1046 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
1047 break;
1048
1049 namesz = NOTE_ALIGN(nhdr.n_namesz);
1050 descsz = NOTE_ALIGN(nhdr.n_descsz);
1051 if (nhdr.n_type == NT_GNU_BUILD_ID &&
1052 nhdr.n_namesz == sizeof("GNU")) {
1053 if (read(fd, bf, namesz) != (ssize_t)namesz)
1054 break;
1055 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
1056 size_t sz = min(descsz, size);
1057 if (read(fd, bid->data, sz) == (ssize_t)sz) {
1058 memset(bid->data + sz, 0, size - sz);
1059 bid->size = sz;
1060 err = 0;
1061 break;
1062 }
1063 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
1064 break;
1065 } else {
1066 int n = namesz + descsz;
1067
1068 if (n > (int)sizeof(bf)) {
1069 n = sizeof(bf);
1070 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
1071 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
1072 }
1073 if (read(fd, bf, n) != n)
1074 break;
1075 }
1076 }
1077 close(fd);
1078out:
1079 return err;
1080}
1081
1082#ifdef HAVE_LIBBFD_SUPPORT
1083
1084int filename__read_debuglink(const char *filename, char *debuglink,
1085 size_t size)
1086{
1087 int err = -1;
1088 asection *section;
1089 bfd *abfd;
1090
1091 abfd = bfd_openr(filename, NULL);
1092 if (!abfd)
1093 return -1;
1094
1095 if (!bfd_check_format(abfd, bfd_object)) {
1096 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
1097 goto out_close;
1098 }
1099
1100 section = bfd_get_section_by_name(abfd, ".gnu_debuglink");
1101 if (!section)
1102 goto out_close;
1103
1104 if (section->size > size)
1105 goto out_close;
1106
1107 if (!bfd_get_section_contents(abfd, section, debuglink, 0,
1108 section->size))
1109 goto out_close;
1110
1111 err = 0;
1112
1113out_close:
1114 bfd_close(abfd);
1115 return err;
1116}
1117
1118#else
1119
1120int filename__read_debuglink(const char *filename, char *debuglink,
1121 size_t size)
1122{
1123 int fd, err = -1;
1124 Elf *elf;
1125 GElf_Ehdr ehdr;
1126 GElf_Shdr shdr;
1127 Elf_Data *data;
1128 Elf_Scn *sec;
1129 Elf_Kind ek;
1130
1131 fd = open(filename, O_RDONLY);
1132 if (fd < 0)
1133 goto out;
1134
1135 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1136 if (elf == NULL) {
1137 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
1138 goto out_close;
1139 }
1140
1141 ek = elf_kind(elf);
1142 if (ek != ELF_K_ELF)
1143 goto out_elf_end;
1144
1145 if (gelf_getehdr(elf, &ehdr) == NULL) {
1146 pr_err("%s: cannot get elf header.\n", __func__);
1147 goto out_elf_end;
1148 }
1149
1150 sec = elf_section_by_name(elf, &ehdr, &shdr,
1151 ".gnu_debuglink", NULL);
1152 if (sec == NULL)
1153 goto out_elf_end;
1154
1155 data = elf_getdata(sec, NULL);
1156 if (data == NULL)
1157 goto out_elf_end;
1158
1159 /* the start of this section is a zero-terminated string */
1160 strncpy(debuglink, data->d_buf, size);
1161
1162 err = 0;
1163
1164out_elf_end:
1165 elf_end(elf);
1166out_close:
1167 close(fd);
1168out:
1169 return err;
1170}
1171
1172#endif
1173
1174static int dso__swap_init(struct dso *dso, unsigned char eidata)
1175{
1176 static unsigned int const endian = 1;
1177
1178 dso->needs_swap = DSO_SWAP__NO;
1179
1180 switch (eidata) {
1181 case ELFDATA2LSB:
1182 /* We are big endian, DSO is little endian. */
1183 if (*(unsigned char const *)&endian != 1)
1184 dso->needs_swap = DSO_SWAP__YES;
1185 break;
1186
1187 case ELFDATA2MSB:
1188 /* We are little endian, DSO is big endian. */
1189 if (*(unsigned char const *)&endian != 0)
1190 dso->needs_swap = DSO_SWAP__YES;
1191 break;
1192
1193 default:
1194 pr_err("unrecognized DSO data encoding %d\n", eidata);
1195 return -EINVAL;
1196 }
1197
1198 return 0;
1199}
1200
1201bool symsrc__possibly_runtime(struct symsrc *ss)
1202{
1203 return ss->dynsym || ss->opdsec;
1204}
1205
1206bool symsrc__has_symtab(struct symsrc *ss)
1207{
1208 return ss->symtab != NULL;
1209}
1210
1211void symsrc__destroy(struct symsrc *ss)
1212{
1213 zfree(&ss->name);
1214 elf_end(ss->elf);
1215 close(ss->fd);
1216}
1217
1218bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
1219{
1220 /*
1221 * Usually vmlinux is an ELF file with type ET_EXEC for most
1222 * architectures; except Arm64 kernel is linked with option
1223 * '-share', so need to check type ET_DYN.
1224 */
1225 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
1226 ehdr.e_type == ET_DYN;
1227}
1228
1229int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
1230 enum dso_binary_type type)
1231{
1232 GElf_Ehdr ehdr;
1233 Elf *elf;
1234 int fd;
1235
1236 if (dso__needs_decompress(dso)) {
1237 fd = dso__decompress_kmodule_fd(dso, name);
1238 if (fd < 0)
1239 return -1;
1240
1241 type = dso->symtab_type;
1242 } else {
1243 fd = open(name, O_RDONLY);
1244 if (fd < 0) {
1245 dso->load_errno = errno;
1246 return -1;
1247 }
1248 }
1249
1250 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1251 if (elf == NULL) {
1252 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
1253 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
1254 goto out_close;
1255 }
1256
1257 if (gelf_getehdr(elf, &ehdr) == NULL) {
1258 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
1259 pr_debug("%s: cannot get elf header.\n", __func__);
1260 goto out_elf_end;
1261 }
1262
1263 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
1264 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
1265 goto out_elf_end;
1266 }
1267
1268 /* Always reject images with a mismatched build-id: */
1269 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
1270 u8 build_id[BUILD_ID_SIZE];
1271 struct build_id bid;
1272 int size;
1273
1274 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);
1275 if (size <= 0) {
1276 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
1277 goto out_elf_end;
1278 }
1279
1280 build_id__init(&bid, build_id, size);
1281 if (!dso__build_id_equal(dso, &bid)) {
1282 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
1283 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
1284 goto out_elf_end;
1285 }
1286 }
1287
1288 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1289
1290 ss->symtab_idx = 0;
1291 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
1292 &ss->symtab_idx);
1293 if (ss->symshdr.sh_type != SHT_SYMTAB)
1294 ss->symtab = NULL;
1295
1296 ss->dynsym_idx = 0;
1297 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
1298 &ss->dynsym_idx);
1299 if (ss->dynshdr.sh_type != SHT_DYNSYM)
1300 ss->dynsym = NULL;
1301
1302 ss->opdidx = 0;
1303 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
1304 &ss->opdidx);
1305 if (ss->opdshdr.sh_type != SHT_PROGBITS)
1306 ss->opdsec = NULL;
1307
1308 if (dso->kernel == DSO_SPACE__USER)
1309 ss->adjust_symbols = true;
1310 else
1311 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
1312
1313 ss->name = strdup(name);
1314 if (!ss->name) {
1315 dso->load_errno = errno;
1316 goto out_elf_end;
1317 }
1318
1319 ss->elf = elf;
1320 ss->fd = fd;
1321 ss->ehdr = ehdr;
1322 ss->type = type;
1323
1324 return 0;
1325
1326out_elf_end:
1327 elf_end(elf);
1328out_close:
1329 close(fd);
1330 return -1;
1331}
1332
1333static bool is_exe_text(int flags)
1334{
1335 return (flags & (SHF_ALLOC | SHF_EXECINSTR)) == (SHF_ALLOC | SHF_EXECINSTR);
1336}
1337
1338/*
1339 * Some executable module sections like .noinstr.text might be laid out with
1340 * .text so they can use the same mapping (memory address to file offset).
1341 * Check if that is the case. Refer to kernel layout_sections(). Return the
1342 * maximum offset.
1343 */
1344static u64 max_text_section(Elf *elf, GElf_Ehdr *ehdr)
1345{
1346 Elf_Scn *sec = NULL;
1347 GElf_Shdr shdr;
1348 u64 offs = 0;
1349
1350 /* Doesn't work for some arch */
1351 if (ehdr->e_machine == EM_PARISC ||
1352 ehdr->e_machine == EM_ALPHA)
1353 return 0;
1354
1355 /* ELF is corrupted/truncated, avoid calling elf_strptr. */
1356 if (!elf_rawdata(elf_getscn(elf, ehdr->e_shstrndx), NULL))
1357 return 0;
1358
1359 while ((sec = elf_nextscn(elf, sec)) != NULL) {
1360 char *sec_name;
1361
1362 if (!gelf_getshdr(sec, &shdr))
1363 break;
1364
1365 if (!is_exe_text(shdr.sh_flags))
1366 continue;
1367
1368 /* .init and .exit sections are not placed with .text */
1369 sec_name = elf_strptr(elf, ehdr->e_shstrndx, shdr.sh_name);
1370 if (!sec_name ||
1371 strstarts(sec_name, ".init") ||
1372 strstarts(sec_name, ".exit"))
1373 break;
1374
1375 /* Must be next to previous, assumes .text is first */
1376 if (offs && PERF_ALIGN(offs, shdr.sh_addralign ?: 1) != shdr.sh_offset)
1377 break;
1378
1379 offs = shdr.sh_offset + shdr.sh_size;
1380 }
1381
1382 return offs;
1383}
1384
1385/**
1386 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
1387 * @kmap: kernel maps and relocation reference symbol
1388 *
1389 * This function returns %true if we are dealing with the kernel maps and the
1390 * relocation reference symbol has not yet been found. Otherwise %false is
1391 * returned.
1392 */
1393static bool ref_reloc_sym_not_found(struct kmap *kmap)
1394{
1395 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
1396 !kmap->ref_reloc_sym->unrelocated_addr;
1397}
1398
1399/**
1400 * ref_reloc - kernel relocation offset.
1401 * @kmap: kernel maps and relocation reference symbol
1402 *
1403 * This function returns the offset of kernel addresses as determined by using
1404 * the relocation reference symbol i.e. if the kernel has not been relocated
1405 * then the return value is zero.
1406 */
1407static u64 ref_reloc(struct kmap *kmap)
1408{
1409 if (kmap && kmap->ref_reloc_sym &&
1410 kmap->ref_reloc_sym->unrelocated_addr)
1411 return kmap->ref_reloc_sym->addr -
1412 kmap->ref_reloc_sym->unrelocated_addr;
1413 return 0;
1414}
1415
1416void __weak arch__sym_update(struct symbol *s __maybe_unused,
1417 GElf_Sym *sym __maybe_unused) { }
1418
1419static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
1420 GElf_Sym *sym, GElf_Shdr *shdr,
1421 struct maps *kmaps, struct kmap *kmap,
1422 struct dso **curr_dsop, struct map **curr_mapp,
1423 const char *section_name,
1424 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel,
1425 u64 max_text_sh_offset)
1426{
1427 struct dso *curr_dso = *curr_dsop;
1428 struct map *curr_map;
1429 char dso_name[PATH_MAX];
1430
1431 /* Adjust symbol to map to file offset */
1432 if (adjust_kernel_syms)
1433 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
1434
1435 if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
1436 return 0;
1437
1438 if (strcmp(section_name, ".text") == 0) {
1439 /*
1440 * The initial kernel mapping is based on
1441 * kallsyms and identity maps. Overwrite it to
1442 * map to the kernel dso.
1443 */
1444 if (*remap_kernel && dso->kernel && !kmodule) {
1445 *remap_kernel = false;
1446 map__set_start(map, shdr->sh_addr + ref_reloc(kmap));
1447 map__set_end(map, map__start(map) + shdr->sh_size);
1448 map__set_pgoff(map, shdr->sh_offset);
1449 map__set_mapping_type(map, MAPPING_TYPE__DSO);
1450 /* Ensure maps are correctly ordered */
1451 if (kmaps) {
1452 int err;
1453 struct map *tmp = map__get(map);
1454
1455 maps__remove(kmaps, map);
1456 err = maps__insert(kmaps, map);
1457 map__put(tmp);
1458 if (err)
1459 return err;
1460 }
1461 }
1462
1463 /*
1464 * The initial module mapping is based on
1465 * /proc/modules mapped to offset zero.
1466 * Overwrite it to map to the module dso.
1467 */
1468 if (*remap_kernel && kmodule) {
1469 *remap_kernel = false;
1470 map__set_pgoff(map, shdr->sh_offset);
1471 }
1472
1473 *curr_mapp = map;
1474 *curr_dsop = dso;
1475 return 0;
1476 }
1477
1478 if (!kmap)
1479 return 0;
1480
1481 /*
1482 * perf does not record module section addresses except for .text, but
1483 * some sections can use the same mapping as .text.
1484 */
1485 if (kmodule && adjust_kernel_syms && is_exe_text(shdr->sh_flags) &&
1486 shdr->sh_offset <= max_text_sh_offset) {
1487 *curr_mapp = map;
1488 *curr_dsop = dso;
1489 return 0;
1490 }
1491
1492 snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
1493
1494 curr_map = maps__find_by_name(kmaps, dso_name);
1495 if (curr_map == NULL) {
1496 u64 start = sym->st_value;
1497
1498 if (kmodule)
1499 start += map__start(map) + shdr->sh_offset;
1500
1501 curr_dso = dso__new(dso_name);
1502 if (curr_dso == NULL)
1503 return -1;
1504 curr_dso->kernel = dso->kernel;
1505 curr_dso->long_name = dso->long_name;
1506 curr_dso->long_name_len = dso->long_name_len;
1507 curr_dso->binary_type = dso->binary_type;
1508 curr_dso->adjust_symbols = dso->adjust_symbols;
1509 curr_map = map__new2(start, curr_dso);
1510 dso__put(curr_dso);
1511 if (curr_map == NULL)
1512 return -1;
1513
1514 if (curr_dso->kernel)
1515 map__kmap(curr_map)->kmaps = kmaps;
1516
1517 if (adjust_kernel_syms) {
1518 map__set_start(curr_map, shdr->sh_addr + ref_reloc(kmap));
1519 map__set_end(curr_map, map__start(curr_map) + shdr->sh_size);
1520 map__set_pgoff(curr_map, shdr->sh_offset);
1521 } else {
1522 map__set_mapping_type(curr_map, MAPPING_TYPE__IDENTITY);
1523 }
1524 curr_dso->symtab_type = dso->symtab_type;
1525 if (maps__insert(kmaps, curr_map))
1526 return -1;
1527 /*
1528 * Add it before we drop the reference to curr_map, i.e. while
1529 * we still are sure to have a reference to this DSO via
1530 * *curr_map->dso.
1531 */
1532 dsos__add(&maps__machine(kmaps)->dsos, curr_dso);
1533 /* kmaps already got it */
1534 map__put(curr_map);
1535 dso__set_loaded(curr_dso);
1536 *curr_mapp = curr_map;
1537 *curr_dsop = curr_dso;
1538 } else {
1539 *curr_dsop = map__dso(curr_map);
1540 map__put(curr_map);
1541 }
1542
1543 return 0;
1544}
1545
1546static int
1547dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1548 struct symsrc *runtime_ss, int kmodule, int dynsym)
1549{
1550 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
1551 struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
1552 struct map *curr_map = map;
1553 struct dso *curr_dso = dso;
1554 Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;
1555 uint32_t nr_syms;
1556 int err = -1;
1557 uint32_t idx;
1558 GElf_Ehdr ehdr;
1559 GElf_Shdr shdr;
1560 GElf_Shdr tshdr;
1561 Elf_Data *syms, *opddata = NULL;
1562 GElf_Sym sym;
1563 Elf_Scn *sec, *sec_strndx;
1564 Elf *elf;
1565 int nr = 0;
1566 bool remap_kernel = false, adjust_kernel_syms = false;
1567 u64 max_text_sh_offset = 0;
1568
1569 if (kmap && !kmaps)
1570 return -1;
1571
1572 elf = syms_ss->elf;
1573 ehdr = syms_ss->ehdr;
1574 if (dynsym) {
1575 sec = syms_ss->dynsym;
1576 shdr = syms_ss->dynshdr;
1577 } else {
1578 sec = syms_ss->symtab;
1579 shdr = syms_ss->symshdr;
1580 }
1581
1582 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1583 ".text", NULL)) {
1584 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1585 dso->text_end = tshdr.sh_offset + tshdr.sh_size;
1586 }
1587
1588 if (runtime_ss->opdsec)
1589 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1590
1591 syms = elf_getdata(sec, NULL);
1592 if (syms == NULL)
1593 goto out_elf_end;
1594
1595 sec = elf_getscn(elf, shdr.sh_link);
1596 if (sec == NULL)
1597 goto out_elf_end;
1598
1599 symstrs = elf_getdata(sec, NULL);
1600 if (symstrs == NULL)
1601 goto out_elf_end;
1602
1603 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1604 if (sec_strndx == NULL)
1605 goto out_elf_end;
1606
1607 secstrs_run = elf_getdata(sec_strndx, NULL);
1608 if (secstrs_run == NULL)
1609 goto out_elf_end;
1610
1611 sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
1612 if (sec_strndx == NULL)
1613 goto out_elf_end;
1614
1615 secstrs_sym = elf_getdata(sec_strndx, NULL);
1616 if (secstrs_sym == NULL)
1617 goto out_elf_end;
1618
1619 nr_syms = shdr.sh_size / shdr.sh_entsize;
1620
1621 memset(&sym, 0, sizeof(sym));
1622
1623 /*
1624 * The kernel relocation symbol is needed in advance in order to adjust
1625 * kernel maps correctly.
1626 */
1627 if (ref_reloc_sym_not_found(kmap)) {
1628 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1629 const char *elf_name = elf_sym__name(&sym, symstrs);
1630
1631 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1632 continue;
1633 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1634 map__set_reloc(map, kmap->ref_reloc_sym->addr - kmap->ref_reloc_sym->unrelocated_addr);
1635 break;
1636 }
1637 }
1638
1639 /*
1640 * Handle any relocation of vdso necessary because older kernels
1641 * attempted to prelink vdso to its virtual address.
1642 */
1643 if (dso__is_vdso(dso))
1644 map__set_reloc(map, map__start(map) - dso->text_offset);
1645
1646 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1647 /*
1648 * Initial kernel and module mappings do not map to the dso.
1649 * Flag the fixups.
1650 */
1651 if (dso->kernel) {
1652 remap_kernel = true;
1653 adjust_kernel_syms = dso->adjust_symbols;
1654 }
1655
1656 if (kmodule && adjust_kernel_syms)
1657 max_text_sh_offset = max_text_section(runtime_ss->elf, &runtime_ss->ehdr);
1658
1659 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1660 struct symbol *f;
1661 const char *elf_name = elf_sym__name(&sym, symstrs);
1662 char *demangled = NULL;
1663 int is_label = elf_sym__is_label(&sym);
1664 const char *section_name;
1665 bool used_opd = false;
1666
1667 if (!is_label && !elf_sym__filter(&sym))
1668 continue;
1669
1670 /* Reject ARM ELF "mapping symbols": these aren't unique and
1671 * don't identify functions, so will confuse the profile
1672 * output: */
1673 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1674 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1675 && (elf_name[2] == '\0' || elf_name[2] == '.'))
1676 continue;
1677 }
1678
1679 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1680 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1681 u64 *opd = opddata->d_buf + offset;
1682 sym.st_value = DSO__SWAP(dso, u64, *opd);
1683 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1684 sym.st_value);
1685 used_opd = true;
1686 }
1687
1688 /*
1689 * When loading symbols in a data mapping, ABS symbols (which
1690 * has a value of SHN_ABS in its st_shndx) failed at
1691 * elf_getscn(). And it marks the loading as a failure so
1692 * already loaded symbols cannot be fixed up.
1693 *
1694 * I'm not sure what should be done. Just ignore them for now.
1695 * - Namhyung Kim
1696 */
1697 if (sym.st_shndx == SHN_ABS)
1698 continue;
1699
1700 sec = elf_getscn(syms_ss->elf, sym.st_shndx);
1701 if (!sec)
1702 goto out_elf_end;
1703
1704 gelf_getshdr(sec, &shdr);
1705
1706 /*
1707 * If the attribute bit SHF_ALLOC is not set, the section
1708 * doesn't occupy memory during process execution.
1709 * E.g. ".gnu.warning.*" section is used by linker to generate
1710 * warnings when calling deprecated functions, the symbols in
1711 * the section aren't loaded to memory during process execution,
1712 * so skip them.
1713 */
1714 if (!(shdr.sh_flags & SHF_ALLOC))
1715 continue;
1716
1717 secstrs = secstrs_sym;
1718
1719 /*
1720 * We have to fallback to runtime when syms' section header has
1721 * NOBITS set. NOBITS results in file offset (sh_offset) not
1722 * being incremented. So sh_offset used below has different
1723 * values for syms (invalid) and runtime (valid).
1724 */
1725 if (shdr.sh_type == SHT_NOBITS) {
1726 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1727 if (!sec)
1728 goto out_elf_end;
1729
1730 gelf_getshdr(sec, &shdr);
1731 secstrs = secstrs_run;
1732 }
1733
1734 if (is_label && !elf_sec__filter(&shdr, secstrs))
1735 continue;
1736
1737 section_name = elf_sec__name(&shdr, secstrs);
1738
1739 /* On ARM, symbols for thumb functions have 1 added to
1740 * the symbol address as a flag - remove it */
1741 if ((ehdr.e_machine == EM_ARM) &&
1742 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1743 (sym.st_value & 1))
1744 --sym.st_value;
1745
1746 if (dso->kernel) {
1747 if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1748 section_name, adjust_kernel_syms, kmodule,
1749 &remap_kernel, max_text_sh_offset))
1750 goto out_elf_end;
1751 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1752 (!used_opd && syms_ss->adjust_symbols)) {
1753 GElf_Phdr phdr;
1754
1755 if (elf_read_program_header(runtime_ss->elf,
1756 (u64)sym.st_value, &phdr)) {
1757 pr_debug4("%s: failed to find program header for "
1758 "symbol: %s st_value: %#" PRIx64 "\n",
1759 __func__, elf_name, (u64)sym.st_value);
1760 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1761 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n",
1762 __func__, (u64)sym.st_value, (u64)shdr.sh_addr,
1763 (u64)shdr.sh_offset);
1764 /*
1765 * Fail to find program header, let's rollback
1766 * to use shdr.sh_addr and shdr.sh_offset to
1767 * calibrate symbol's file address, though this
1768 * is not necessary for normal C ELF file, we
1769 * still need to handle java JIT symbols in this
1770 * case.
1771 */
1772 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1773 } else {
1774 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1775 "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",
1776 __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,
1777 (u64)phdr.p_offset);
1778 sym.st_value -= phdr.p_vaddr - phdr.p_offset;
1779 }
1780 }
1781
1782 demangled = demangle_sym(dso, kmodule, elf_name);
1783 if (demangled != NULL)
1784 elf_name = demangled;
1785
1786 f = symbol__new(sym.st_value, sym.st_size,
1787 GELF_ST_BIND(sym.st_info),
1788 GELF_ST_TYPE(sym.st_info), elf_name);
1789 free(demangled);
1790 if (!f)
1791 goto out_elf_end;
1792
1793 arch__sym_update(f, &sym);
1794
1795 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1796 nr++;
1797 }
1798
1799 /*
1800 * For misannotated, zeroed, ASM function sizes.
1801 */
1802 if (nr > 0) {
1803 symbols__fixup_end(&dso->symbols, false);
1804 symbols__fixup_duplicate(&dso->symbols);
1805 if (kmap) {
1806 /*
1807 * We need to fixup this here too because we create new
1808 * maps here, for things like vsyscall sections.
1809 */
1810 maps__fixup_end(kmaps);
1811 }
1812 }
1813 err = nr;
1814out_elf_end:
1815 return err;
1816}
1817
1818int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1819 struct symsrc *runtime_ss, int kmodule)
1820{
1821 int nr = 0;
1822 int err = -1;
1823
1824 dso->symtab_type = syms_ss->type;
1825 dso->is_64_bit = syms_ss->is_64_bit;
1826 dso->rel = syms_ss->ehdr.e_type == ET_REL;
1827
1828 /*
1829 * Modules may already have symbols from kallsyms, but those symbols
1830 * have the wrong values for the dso maps, so remove them.
1831 */
1832 if (kmodule && syms_ss->symtab)
1833 symbols__delete(&dso->symbols);
1834
1835 if (!syms_ss->symtab) {
1836 /*
1837 * If the vmlinux is stripped, fail so we will fall back
1838 * to using kallsyms. The vmlinux runtime symbols aren't
1839 * of much use.
1840 */
1841 if (dso->kernel)
1842 return err;
1843 } else {
1844 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1845 kmodule, 0);
1846 if (err < 0)
1847 return err;
1848 nr = err;
1849 }
1850
1851 if (syms_ss->dynsym) {
1852 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1853 kmodule, 1);
1854 if (err < 0)
1855 return err;
1856 err += nr;
1857 }
1858
1859 return err;
1860}
1861
1862static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1863{
1864 GElf_Phdr phdr;
1865 size_t i, phdrnum;
1866 int err;
1867 u64 sz;
1868
1869 if (elf_getphdrnum(elf, &phdrnum))
1870 return -1;
1871
1872 for (i = 0; i < phdrnum; i++) {
1873 if (gelf_getphdr(elf, i, &phdr) == NULL)
1874 return -1;
1875 if (phdr.p_type != PT_LOAD)
1876 continue;
1877 if (exe) {
1878 if (!(phdr.p_flags & PF_X))
1879 continue;
1880 } else {
1881 if (!(phdr.p_flags & PF_R))
1882 continue;
1883 }
1884 sz = min(phdr.p_memsz, phdr.p_filesz);
1885 if (!sz)
1886 continue;
1887 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1888 if (err)
1889 return err;
1890 }
1891 return 0;
1892}
1893
1894int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1895 bool *is_64_bit)
1896{
1897 int err;
1898 Elf *elf;
1899
1900 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1901 if (elf == NULL)
1902 return -1;
1903
1904 if (is_64_bit)
1905 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1906
1907 err = elf_read_maps(elf, exe, mapfn, data);
1908
1909 elf_end(elf);
1910 return err;
1911}
1912
1913enum dso_type dso__type_fd(int fd)
1914{
1915 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1916 GElf_Ehdr ehdr;
1917 Elf_Kind ek;
1918 Elf *elf;
1919
1920 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1921 if (elf == NULL)
1922 goto out;
1923
1924 ek = elf_kind(elf);
1925 if (ek != ELF_K_ELF)
1926 goto out_end;
1927
1928 if (gelf_getclass(elf) == ELFCLASS64) {
1929 dso_type = DSO__TYPE_64BIT;
1930 goto out_end;
1931 }
1932
1933 if (gelf_getehdr(elf, &ehdr) == NULL)
1934 goto out_end;
1935
1936 if (ehdr.e_machine == EM_X86_64)
1937 dso_type = DSO__TYPE_X32BIT;
1938 else
1939 dso_type = DSO__TYPE_32BIT;
1940out_end:
1941 elf_end(elf);
1942out:
1943 return dso_type;
1944}
1945
1946static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1947{
1948 ssize_t r;
1949 size_t n;
1950 int err = -1;
1951 char *buf = malloc(page_size);
1952
1953 if (buf == NULL)
1954 return -1;
1955
1956 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1957 goto out;
1958
1959 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1960 goto out;
1961
1962 while (len) {
1963 n = page_size;
1964 if (len < n)
1965 n = len;
1966 /* Use read because mmap won't work on proc files */
1967 r = read(from, buf, n);
1968 if (r < 0)
1969 goto out;
1970 if (!r)
1971 break;
1972 n = r;
1973 r = write(to, buf, n);
1974 if (r < 0)
1975 goto out;
1976 if ((size_t)r != n)
1977 goto out;
1978 len -= n;
1979 }
1980
1981 err = 0;
1982out:
1983 free(buf);
1984 return err;
1985}
1986
1987struct kcore {
1988 int fd;
1989 int elfclass;
1990 Elf *elf;
1991 GElf_Ehdr ehdr;
1992};
1993
1994static int kcore__open(struct kcore *kcore, const char *filename)
1995{
1996 GElf_Ehdr *ehdr;
1997
1998 kcore->fd = open(filename, O_RDONLY);
1999 if (kcore->fd == -1)
2000 return -1;
2001
2002 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
2003 if (!kcore->elf)
2004 goto out_close;
2005
2006 kcore->elfclass = gelf_getclass(kcore->elf);
2007 if (kcore->elfclass == ELFCLASSNONE)
2008 goto out_end;
2009
2010 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
2011 if (!ehdr)
2012 goto out_end;
2013
2014 return 0;
2015
2016out_end:
2017 elf_end(kcore->elf);
2018out_close:
2019 close(kcore->fd);
2020 return -1;
2021}
2022
2023static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
2024 bool temp)
2025{
2026 kcore->elfclass = elfclass;
2027
2028 if (temp)
2029 kcore->fd = mkstemp(filename);
2030 else
2031 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
2032 if (kcore->fd == -1)
2033 return -1;
2034
2035 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
2036 if (!kcore->elf)
2037 goto out_close;
2038
2039 if (!gelf_newehdr(kcore->elf, elfclass))
2040 goto out_end;
2041
2042 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
2043
2044 return 0;
2045
2046out_end:
2047 elf_end(kcore->elf);
2048out_close:
2049 close(kcore->fd);
2050 unlink(filename);
2051 return -1;
2052}
2053
2054static void kcore__close(struct kcore *kcore)
2055{
2056 elf_end(kcore->elf);
2057 close(kcore->fd);
2058}
2059
2060static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
2061{
2062 GElf_Ehdr *ehdr = &to->ehdr;
2063 GElf_Ehdr *kehdr = &from->ehdr;
2064
2065 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
2066 ehdr->e_type = kehdr->e_type;
2067 ehdr->e_machine = kehdr->e_machine;
2068 ehdr->e_version = kehdr->e_version;
2069 ehdr->e_entry = 0;
2070 ehdr->e_shoff = 0;
2071 ehdr->e_flags = kehdr->e_flags;
2072 ehdr->e_phnum = count;
2073 ehdr->e_shentsize = 0;
2074 ehdr->e_shnum = 0;
2075 ehdr->e_shstrndx = 0;
2076
2077 if (from->elfclass == ELFCLASS32) {
2078 ehdr->e_phoff = sizeof(Elf32_Ehdr);
2079 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
2080 ehdr->e_phentsize = sizeof(Elf32_Phdr);
2081 } else {
2082 ehdr->e_phoff = sizeof(Elf64_Ehdr);
2083 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
2084 ehdr->e_phentsize = sizeof(Elf64_Phdr);
2085 }
2086
2087 if (!gelf_update_ehdr(to->elf, ehdr))
2088 return -1;
2089
2090 if (!gelf_newphdr(to->elf, count))
2091 return -1;
2092
2093 return 0;
2094}
2095
2096static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
2097 u64 addr, u64 len)
2098{
2099 GElf_Phdr phdr = {
2100 .p_type = PT_LOAD,
2101 .p_flags = PF_R | PF_W | PF_X,
2102 .p_offset = offset,
2103 .p_vaddr = addr,
2104 .p_paddr = 0,
2105 .p_filesz = len,
2106 .p_memsz = len,
2107 .p_align = page_size,
2108 };
2109
2110 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
2111 return -1;
2112
2113 return 0;
2114}
2115
2116static off_t kcore__write(struct kcore *kcore)
2117{
2118 return elf_update(kcore->elf, ELF_C_WRITE);
2119}
2120
2121struct phdr_data {
2122 off_t offset;
2123 off_t rel;
2124 u64 addr;
2125 u64 len;
2126 struct list_head node;
2127 struct phdr_data *remaps;
2128};
2129
2130struct sym_data {
2131 u64 addr;
2132 struct list_head node;
2133};
2134
2135struct kcore_copy_info {
2136 u64 stext;
2137 u64 etext;
2138 u64 first_symbol;
2139 u64 last_symbol;
2140 u64 first_module;
2141 u64 first_module_symbol;
2142 u64 last_module_symbol;
2143 size_t phnum;
2144 struct list_head phdrs;
2145 struct list_head syms;
2146};
2147
2148#define kcore_copy__for_each_phdr(k, p) \
2149 list_for_each_entry((p), &(k)->phdrs, node)
2150
2151static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
2152{
2153 struct phdr_data *p = zalloc(sizeof(*p));
2154
2155 if (p) {
2156 p->addr = addr;
2157 p->len = len;
2158 p->offset = offset;
2159 }
2160
2161 return p;
2162}
2163
2164static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
2165 u64 addr, u64 len,
2166 off_t offset)
2167{
2168 struct phdr_data *p = phdr_data__new(addr, len, offset);
2169
2170 if (p)
2171 list_add_tail(&p->node, &kci->phdrs);
2172
2173 return p;
2174}
2175
2176static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
2177{
2178 struct phdr_data *p, *tmp;
2179
2180 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
2181 list_del_init(&p->node);
2182 free(p);
2183 }
2184}
2185
2186static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
2187 u64 addr)
2188{
2189 struct sym_data *s = zalloc(sizeof(*s));
2190
2191 if (s) {
2192 s->addr = addr;
2193 list_add_tail(&s->node, &kci->syms);
2194 }
2195
2196 return s;
2197}
2198
2199static void kcore_copy__free_syms(struct kcore_copy_info *kci)
2200{
2201 struct sym_data *s, *tmp;
2202
2203 list_for_each_entry_safe(s, tmp, &kci->syms, node) {
2204 list_del_init(&s->node);
2205 free(s);
2206 }
2207}
2208
2209static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
2210 u64 start)
2211{
2212 struct kcore_copy_info *kci = arg;
2213
2214 if (!kallsyms__is_function(type))
2215 return 0;
2216
2217 if (strchr(name, '[')) {
2218 if (!kci->first_module_symbol || start < kci->first_module_symbol)
2219 kci->first_module_symbol = start;
2220 if (start > kci->last_module_symbol)
2221 kci->last_module_symbol = start;
2222 return 0;
2223 }
2224
2225 if (!kci->first_symbol || start < kci->first_symbol)
2226 kci->first_symbol = start;
2227
2228 if (!kci->last_symbol || start > kci->last_symbol)
2229 kci->last_symbol = start;
2230
2231 if (!strcmp(name, "_stext")) {
2232 kci->stext = start;
2233 return 0;
2234 }
2235
2236 if (!strcmp(name, "_etext")) {
2237 kci->etext = start;
2238 return 0;
2239 }
2240
2241 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
2242 return -1;
2243
2244 return 0;
2245}
2246
2247static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
2248 const char *dir)
2249{
2250 char kallsyms_filename[PATH_MAX];
2251
2252 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
2253
2254 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
2255 return -1;
2256
2257 if (kallsyms__parse(kallsyms_filename, kci,
2258 kcore_copy__process_kallsyms) < 0)
2259 return -1;
2260
2261 return 0;
2262}
2263
2264static int kcore_copy__process_modules(void *arg,
2265 const char *name __maybe_unused,
2266 u64 start, u64 size __maybe_unused)
2267{
2268 struct kcore_copy_info *kci = arg;
2269
2270 if (!kci->first_module || start < kci->first_module)
2271 kci->first_module = start;
2272
2273 return 0;
2274}
2275
2276static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
2277 const char *dir)
2278{
2279 char modules_filename[PATH_MAX];
2280
2281 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
2282
2283 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
2284 return -1;
2285
2286 if (modules__parse(modules_filename, kci,
2287 kcore_copy__process_modules) < 0)
2288 return -1;
2289
2290 return 0;
2291}
2292
2293static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
2294 u64 pgoff, u64 s, u64 e)
2295{
2296 u64 len, offset;
2297
2298 if (s < start || s >= end)
2299 return 0;
2300
2301 offset = (s - start) + pgoff;
2302 len = e < end ? e - s : end - s;
2303
2304 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
2305}
2306
2307static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
2308{
2309 struct kcore_copy_info *kci = data;
2310 u64 end = start + len;
2311 struct sym_data *sdat;
2312
2313 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
2314 return -1;
2315
2316 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
2317 kci->last_module_symbol))
2318 return -1;
2319
2320 list_for_each_entry(sdat, &kci->syms, node) {
2321 u64 s = round_down(sdat->addr, page_size);
2322
2323 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
2324 return -1;
2325 }
2326
2327 return 0;
2328}
2329
2330static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
2331{
2332 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
2333 return -1;
2334
2335 return 0;
2336}
2337
2338static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
2339{
2340 struct phdr_data *p, *k = NULL;
2341 u64 kend;
2342
2343 if (!kci->stext)
2344 return;
2345
2346 /* Find phdr that corresponds to the kernel map (contains stext) */
2347 kcore_copy__for_each_phdr(kci, p) {
2348 u64 pend = p->addr + p->len - 1;
2349
2350 if (p->addr <= kci->stext && pend >= kci->stext) {
2351 k = p;
2352 break;
2353 }
2354 }
2355
2356 if (!k)
2357 return;
2358
2359 kend = k->offset + k->len;
2360
2361 /* Find phdrs that remap the kernel */
2362 kcore_copy__for_each_phdr(kci, p) {
2363 u64 pend = p->offset + p->len;
2364
2365 if (p == k)
2366 continue;
2367
2368 if (p->offset >= k->offset && pend <= kend)
2369 p->remaps = k;
2370 }
2371}
2372
2373static void kcore_copy__layout(struct kcore_copy_info *kci)
2374{
2375 struct phdr_data *p;
2376 off_t rel = 0;
2377
2378 kcore_copy__find_remaps(kci);
2379
2380 kcore_copy__for_each_phdr(kci, p) {
2381 if (!p->remaps) {
2382 p->rel = rel;
2383 rel += p->len;
2384 }
2385 kci->phnum += 1;
2386 }
2387
2388 kcore_copy__for_each_phdr(kci, p) {
2389 struct phdr_data *k = p->remaps;
2390
2391 if (k)
2392 p->rel = p->offset - k->offset + k->rel;
2393 }
2394}
2395
2396static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
2397 Elf *elf)
2398{
2399 if (kcore_copy__parse_kallsyms(kci, dir))
2400 return -1;
2401
2402 if (kcore_copy__parse_modules(kci, dir))
2403 return -1;
2404
2405 if (kci->stext)
2406 kci->stext = round_down(kci->stext, page_size);
2407 else
2408 kci->stext = round_down(kci->first_symbol, page_size);
2409
2410 if (kci->etext) {
2411 kci->etext = round_up(kci->etext, page_size);
2412 } else if (kci->last_symbol) {
2413 kci->etext = round_up(kci->last_symbol, page_size);
2414 kci->etext += page_size;
2415 }
2416
2417 if (kci->first_module_symbol &&
2418 (!kci->first_module || kci->first_module_symbol < kci->first_module))
2419 kci->first_module = kci->first_module_symbol;
2420
2421 kci->first_module = round_down(kci->first_module, page_size);
2422
2423 if (kci->last_module_symbol) {
2424 kci->last_module_symbol = round_up(kci->last_module_symbol,
2425 page_size);
2426 kci->last_module_symbol += page_size;
2427 }
2428
2429 if (!kci->stext || !kci->etext)
2430 return -1;
2431
2432 if (kci->first_module && !kci->last_module_symbol)
2433 return -1;
2434
2435 if (kcore_copy__read_maps(kci, elf))
2436 return -1;
2437
2438 kcore_copy__layout(kci);
2439
2440 return 0;
2441}
2442
2443static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
2444 const char *name)
2445{
2446 char from_filename[PATH_MAX];
2447 char to_filename[PATH_MAX];
2448
2449 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2450 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2451
2452 return copyfile_mode(from_filename, to_filename, 0400);
2453}
2454
2455static int kcore_copy__unlink(const char *dir, const char *name)
2456{
2457 char filename[PATH_MAX];
2458
2459 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
2460
2461 return unlink(filename);
2462}
2463
2464static int kcore_copy__compare_fds(int from, int to)
2465{
2466 char *buf_from;
2467 char *buf_to;
2468 ssize_t ret;
2469 size_t len;
2470 int err = -1;
2471
2472 buf_from = malloc(page_size);
2473 buf_to = malloc(page_size);
2474 if (!buf_from || !buf_to)
2475 goto out;
2476
2477 while (1) {
2478 /* Use read because mmap won't work on proc files */
2479 ret = read(from, buf_from, page_size);
2480 if (ret < 0)
2481 goto out;
2482
2483 if (!ret)
2484 break;
2485
2486 len = ret;
2487
2488 if (readn(to, buf_to, len) != (int)len)
2489 goto out;
2490
2491 if (memcmp(buf_from, buf_to, len))
2492 goto out;
2493 }
2494
2495 err = 0;
2496out:
2497 free(buf_to);
2498 free(buf_from);
2499 return err;
2500}
2501
2502static int kcore_copy__compare_files(const char *from_filename,
2503 const char *to_filename)
2504{
2505 int from, to, err = -1;
2506
2507 from = open(from_filename, O_RDONLY);
2508 if (from < 0)
2509 return -1;
2510
2511 to = open(to_filename, O_RDONLY);
2512 if (to < 0)
2513 goto out_close_from;
2514
2515 err = kcore_copy__compare_fds(from, to);
2516
2517 close(to);
2518out_close_from:
2519 close(from);
2520 return err;
2521}
2522
2523static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
2524 const char *name)
2525{
2526 char from_filename[PATH_MAX];
2527 char to_filename[PATH_MAX];
2528
2529 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2530 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2531
2532 return kcore_copy__compare_files(from_filename, to_filename);
2533}
2534
2535/**
2536 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
2537 * @from_dir: from directory
2538 * @to_dir: to directory
2539 *
2540 * This function copies kallsyms, modules and kcore files from one directory to
2541 * another. kallsyms and modules are copied entirely. Only code segments are
2542 * copied from kcore. It is assumed that two segments suffice: one for the
2543 * kernel proper and one for all the modules. The code segments are determined
2544 * from kallsyms and modules files. The kernel map starts at _stext or the
2545 * lowest function symbol, and ends at _etext or the highest function symbol.
2546 * The module map starts at the lowest module address and ends at the highest
2547 * module symbol. Start addresses are rounded down to the nearest page. End
2548 * addresses are rounded up to the nearest page. An extra page is added to the
2549 * highest kernel symbol and highest module symbol to, hopefully, encompass that
2550 * symbol too. Because it contains only code sections, the resulting kcore is
2551 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
2552 * is not the same for the kernel map and the modules map. That happens because
2553 * the data is copied adjacently whereas the original kcore has gaps. Finally,
2554 * kallsyms file is compared with its copy to check that modules have not been
2555 * loaded or unloaded while the copies were taking place.
2556 *
2557 * Return: %0 on success, %-1 on failure.
2558 */
2559int kcore_copy(const char *from_dir, const char *to_dir)
2560{
2561 struct kcore kcore;
2562 struct kcore extract;
2563 int idx = 0, err = -1;
2564 off_t offset, sz;
2565 struct kcore_copy_info kci = { .stext = 0, };
2566 char kcore_filename[PATH_MAX];
2567 char extract_filename[PATH_MAX];
2568 struct phdr_data *p;
2569
2570 INIT_LIST_HEAD(&kci.phdrs);
2571 INIT_LIST_HEAD(&kci.syms);
2572
2573 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
2574 return -1;
2575
2576 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
2577 goto out_unlink_kallsyms;
2578
2579 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
2580 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
2581
2582 if (kcore__open(&kcore, kcore_filename))
2583 goto out_unlink_modules;
2584
2585 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
2586 goto out_kcore_close;
2587
2588 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
2589 goto out_kcore_close;
2590
2591 if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
2592 goto out_extract_close;
2593
2594 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
2595 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
2596 offset = round_up(offset, page_size);
2597
2598 kcore_copy__for_each_phdr(&kci, p) {
2599 off_t offs = p->rel + offset;
2600
2601 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
2602 goto out_extract_close;
2603 }
2604
2605 sz = kcore__write(&extract);
2606 if (sz < 0 || sz > offset)
2607 goto out_extract_close;
2608
2609 kcore_copy__for_each_phdr(&kci, p) {
2610 off_t offs = p->rel + offset;
2611
2612 if (p->remaps)
2613 continue;
2614 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
2615 goto out_extract_close;
2616 }
2617
2618 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
2619 goto out_extract_close;
2620
2621 err = 0;
2622
2623out_extract_close:
2624 kcore__close(&extract);
2625 if (err)
2626 unlink(extract_filename);
2627out_kcore_close:
2628 kcore__close(&kcore);
2629out_unlink_modules:
2630 if (err)
2631 kcore_copy__unlink(to_dir, "modules");
2632out_unlink_kallsyms:
2633 if (err)
2634 kcore_copy__unlink(to_dir, "kallsyms");
2635
2636 kcore_copy__free_phdrs(&kci);
2637 kcore_copy__free_syms(&kci);
2638
2639 return err;
2640}
2641
2642int kcore_extract__create(struct kcore_extract *kce)
2643{
2644 struct kcore kcore;
2645 struct kcore extract;
2646 size_t count = 1;
2647 int idx = 0, err = -1;
2648 off_t offset = page_size, sz;
2649
2650 if (kcore__open(&kcore, kce->kcore_filename))
2651 return -1;
2652
2653 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
2654 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
2655 goto out_kcore_close;
2656
2657 if (kcore__copy_hdr(&kcore, &extract, count))
2658 goto out_extract_close;
2659
2660 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
2661 goto out_extract_close;
2662
2663 sz = kcore__write(&extract);
2664 if (sz < 0 || sz > offset)
2665 goto out_extract_close;
2666
2667 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
2668 goto out_extract_close;
2669
2670 err = 0;
2671
2672out_extract_close:
2673 kcore__close(&extract);
2674 if (err)
2675 unlink(kce->extract_filename);
2676out_kcore_close:
2677 kcore__close(&kcore);
2678
2679 return err;
2680}
2681
2682void kcore_extract__delete(struct kcore_extract *kce)
2683{
2684 unlink(kce->extract_filename);
2685}
2686
2687#ifdef HAVE_GELF_GETNOTE_SUPPORT
2688
2689static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2690{
2691 if (!base_off)
2692 return;
2693
2694 if (tmp->bit32)
2695 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2696 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2697 tmp->addr.a32[SDT_NOTE_IDX_BASE];
2698 else
2699 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2700 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2701 tmp->addr.a64[SDT_NOTE_IDX_BASE];
2702}
2703
2704static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2705 GElf_Addr base_off)
2706{
2707 if (!base_off)
2708 return;
2709
2710 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2711 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2712 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2713 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2714}
2715
2716/**
2717 * populate_sdt_note : Parse raw data and identify SDT note
2718 * @elf: elf of the opened file
2719 * @data: raw data of a section with description offset applied
2720 * @len: note description size
2721 * @type: type of the note
2722 * @sdt_notes: List to add the SDT note
2723 *
2724 * Responsible for parsing the @data in section .note.stapsdt in @elf and
2725 * if its an SDT note, it appends to @sdt_notes list.
2726 */
2727static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2728 struct list_head *sdt_notes)
2729{
2730 const char *provider, *name, *args;
2731 struct sdt_note *tmp = NULL;
2732 GElf_Ehdr ehdr;
2733 GElf_Shdr shdr;
2734 int ret = -EINVAL;
2735
2736 union {
2737 Elf64_Addr a64[NR_ADDR];
2738 Elf32_Addr a32[NR_ADDR];
2739 } buf;
2740
2741 Elf_Data dst = {
2742 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2743 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2744 .d_off = 0, .d_align = 0
2745 };
2746 Elf_Data src = {
2747 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2748 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2749 .d_align = 0
2750 };
2751
2752 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2753 if (!tmp) {
2754 ret = -ENOMEM;
2755 goto out_err;
2756 }
2757
2758 INIT_LIST_HEAD(&tmp->note_list);
2759
2760 if (len < dst.d_size + 3)
2761 goto out_free_note;
2762
2763 /* Translation from file representation to memory representation */
2764 if (gelf_xlatetom(*elf, &dst, &src,
2765 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2766 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2767 goto out_free_note;
2768 }
2769
2770 /* Populate the fields of sdt_note */
2771 provider = data + dst.d_size;
2772
2773 name = (const char *)memchr(provider, '\0', data + len - provider);
2774 if (name++ == NULL)
2775 goto out_free_note;
2776
2777 tmp->provider = strdup(provider);
2778 if (!tmp->provider) {
2779 ret = -ENOMEM;
2780 goto out_free_note;
2781 }
2782 tmp->name = strdup(name);
2783 if (!tmp->name) {
2784 ret = -ENOMEM;
2785 goto out_free_prov;
2786 }
2787
2788 args = memchr(name, '\0', data + len - name);
2789
2790 /*
2791 * There is no argument if:
2792 * - We reached the end of the note;
2793 * - There is not enough room to hold a potential string;
2794 * - The argument string is empty or just contains ':'.
2795 */
2796 if (args == NULL || data + len - args < 2 ||
2797 args[1] == ':' || args[1] == '\0')
2798 tmp->args = NULL;
2799 else {
2800 tmp->args = strdup(++args);
2801 if (!tmp->args) {
2802 ret = -ENOMEM;
2803 goto out_free_name;
2804 }
2805 }
2806
2807 if (gelf_getclass(*elf) == ELFCLASS32) {
2808 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2809 tmp->bit32 = true;
2810 } else {
2811 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2812 tmp->bit32 = false;
2813 }
2814
2815 if (!gelf_getehdr(*elf, &ehdr)) {
2816 pr_debug("%s : cannot get elf header.\n", __func__);
2817 ret = -EBADF;
2818 goto out_free_args;
2819 }
2820
2821 /* Adjust the prelink effect :
2822 * Find out the .stapsdt.base section.
2823 * This scn will help us to handle prelinking (if present).
2824 * Compare the retrieved file offset of the base section with the
2825 * base address in the description of the SDT note. If its different,
2826 * then accordingly, adjust the note location.
2827 */
2828 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2829 sdt_adjust_loc(tmp, shdr.sh_offset);
2830
2831 /* Adjust reference counter offset */
2832 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2833 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2834
2835 list_add_tail(&tmp->note_list, sdt_notes);
2836 return 0;
2837
2838out_free_args:
2839 zfree(&tmp->args);
2840out_free_name:
2841 zfree(&tmp->name);
2842out_free_prov:
2843 zfree(&tmp->provider);
2844out_free_note:
2845 free(tmp);
2846out_err:
2847 return ret;
2848}
2849
2850/**
2851 * construct_sdt_notes_list : constructs a list of SDT notes
2852 * @elf : elf to look into
2853 * @sdt_notes : empty list_head
2854 *
2855 * Scans the sections in 'elf' for the section
2856 * .note.stapsdt. It, then calls populate_sdt_note to find
2857 * out the SDT events and populates the 'sdt_notes'.
2858 */
2859static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2860{
2861 GElf_Ehdr ehdr;
2862 Elf_Scn *scn = NULL;
2863 Elf_Data *data;
2864 GElf_Shdr shdr;
2865 size_t shstrndx, next;
2866 GElf_Nhdr nhdr;
2867 size_t name_off, desc_off, offset;
2868 int ret = 0;
2869
2870 if (gelf_getehdr(elf, &ehdr) == NULL) {
2871 ret = -EBADF;
2872 goto out_ret;
2873 }
2874 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2875 ret = -EBADF;
2876 goto out_ret;
2877 }
2878
2879 /* Look for the required section */
2880 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2881 if (!scn) {
2882 ret = -ENOENT;
2883 goto out_ret;
2884 }
2885
2886 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2887 ret = -ENOENT;
2888 goto out_ret;
2889 }
2890
2891 data = elf_getdata(scn, NULL);
2892
2893 /* Get the SDT notes */
2894 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2895 &desc_off)) > 0; offset = next) {
2896 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2897 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2898 sizeof(SDT_NOTE_NAME))) {
2899 /* Check the type of the note */
2900 if (nhdr.n_type != SDT_NOTE_TYPE)
2901 goto out_ret;
2902
2903 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2904 nhdr.n_descsz, sdt_notes);
2905 if (ret < 0)
2906 goto out_ret;
2907 }
2908 }
2909 if (list_empty(sdt_notes))
2910 ret = -ENOENT;
2911
2912out_ret:
2913 return ret;
2914}
2915
2916/**
2917 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2918 * @head : empty list_head
2919 * @target : file to find SDT notes from
2920 *
2921 * This opens the file, initializes
2922 * the ELF and then calls construct_sdt_notes_list.
2923 */
2924int get_sdt_note_list(struct list_head *head, const char *target)
2925{
2926 Elf *elf;
2927 int fd, ret;
2928
2929 fd = open(target, O_RDONLY);
2930 if (fd < 0)
2931 return -EBADF;
2932
2933 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2934 if (!elf) {
2935 ret = -EBADF;
2936 goto out_close;
2937 }
2938 ret = construct_sdt_notes_list(elf, head);
2939 elf_end(elf);
2940out_close:
2941 close(fd);
2942 return ret;
2943}
2944
2945/**
2946 * cleanup_sdt_note_list : free the sdt notes' list
2947 * @sdt_notes: sdt notes' list
2948 *
2949 * Free up the SDT notes in @sdt_notes.
2950 * Returns the number of SDT notes free'd.
2951 */
2952int cleanup_sdt_note_list(struct list_head *sdt_notes)
2953{
2954 struct sdt_note *tmp, *pos;
2955 int nr_free = 0;
2956
2957 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2958 list_del_init(&pos->note_list);
2959 zfree(&pos->args);
2960 zfree(&pos->name);
2961 zfree(&pos->provider);
2962 free(pos);
2963 nr_free++;
2964 }
2965 return nr_free;
2966}
2967
2968/**
2969 * sdt_notes__get_count: Counts the number of sdt events
2970 * @start: list_head to sdt_notes list
2971 *
2972 * Returns the number of SDT notes in a list
2973 */
2974int sdt_notes__get_count(struct list_head *start)
2975{
2976 struct sdt_note *sdt_ptr;
2977 int count = 0;
2978
2979 list_for_each_entry(sdt_ptr, start, note_list)
2980 count++;
2981 return count;
2982}
2983#endif
2984
2985void symbol__elf_init(void)
2986{
2987 elf_version(EV_CURRENT);
2988}