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[mirror_ubuntu-zesty-kernel.git] / tools / perf / util / symbol-elf.c
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 "machine.h"
10 #include "vdso.h"
11 #include <symbol/kallsyms.h>
12 #include "debug.h"
13
14 #ifndef EM_AARCH64
15 #define EM_AARCH64 183 /* ARM 64 bit */
16 #endif
17
18
19 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
20 extern char *cplus_demangle(const char *, int);
21
22 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
23 {
24 return cplus_demangle(c, i);
25 }
26 #else
27 #ifdef NO_DEMANGLE
28 static inline char *bfd_demangle(void __maybe_unused *v,
29 const char __maybe_unused *c,
30 int __maybe_unused i)
31 {
32 return NULL;
33 }
34 #else
35 #define PACKAGE 'perf'
36 #include <bfd.h>
37 #endif
38 #endif
39
40 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
41 static int elf_getphdrnum(Elf *elf, size_t *dst)
42 {
43 GElf_Ehdr gehdr;
44 GElf_Ehdr *ehdr;
45
46 ehdr = gelf_getehdr(elf, &gehdr);
47 if (!ehdr)
48 return -1;
49
50 *dst = ehdr->e_phnum;
51
52 return 0;
53 }
54 #endif
55
56 #ifndef NT_GNU_BUILD_ID
57 #define NT_GNU_BUILD_ID 3
58 #endif
59
60 /**
61 * elf_symtab__for_each_symbol - iterate thru all the symbols
62 *
63 * @syms: struct elf_symtab instance to iterate
64 * @idx: uint32_t idx
65 * @sym: GElf_Sym iterator
66 */
67 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
68 for (idx = 0, gelf_getsym(syms, idx, &sym);\
69 idx < nr_syms; \
70 idx++, gelf_getsym(syms, idx, &sym))
71
72 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
73 {
74 return GELF_ST_TYPE(sym->st_info);
75 }
76
77 #ifndef STT_GNU_IFUNC
78 #define STT_GNU_IFUNC 10
79 #endif
80
81 static inline int elf_sym__is_function(const GElf_Sym *sym)
82 {
83 return (elf_sym__type(sym) == STT_FUNC ||
84 elf_sym__type(sym) == STT_GNU_IFUNC) &&
85 sym->st_name != 0 &&
86 sym->st_shndx != SHN_UNDEF;
87 }
88
89 static inline bool elf_sym__is_object(const GElf_Sym *sym)
90 {
91 return elf_sym__type(sym) == STT_OBJECT &&
92 sym->st_name != 0 &&
93 sym->st_shndx != SHN_UNDEF;
94 }
95
96 static inline int elf_sym__is_label(const GElf_Sym *sym)
97 {
98 return elf_sym__type(sym) == STT_NOTYPE &&
99 sym->st_name != 0 &&
100 sym->st_shndx != SHN_UNDEF &&
101 sym->st_shndx != SHN_ABS;
102 }
103
104 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
105 {
106 switch (type) {
107 case MAP__FUNCTION:
108 return elf_sym__is_function(sym);
109 case MAP__VARIABLE:
110 return elf_sym__is_object(sym);
111 default:
112 return false;
113 }
114 }
115
116 static inline const char *elf_sym__name(const GElf_Sym *sym,
117 const Elf_Data *symstrs)
118 {
119 return symstrs->d_buf + sym->st_name;
120 }
121
122 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
123 const Elf_Data *secstrs)
124 {
125 return secstrs->d_buf + shdr->sh_name;
126 }
127
128 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
129 const Elf_Data *secstrs)
130 {
131 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
132 }
133
134 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
135 const Elf_Data *secstrs)
136 {
137 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
138 }
139
140 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
141 enum map_type type)
142 {
143 switch (type) {
144 case MAP__FUNCTION:
145 return elf_sec__is_text(shdr, secstrs);
146 case MAP__VARIABLE:
147 return elf_sec__is_data(shdr, secstrs);
148 default:
149 return false;
150 }
151 }
152
153 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
154 {
155 Elf_Scn *sec = NULL;
156 GElf_Shdr shdr;
157 size_t cnt = 1;
158
159 while ((sec = elf_nextscn(elf, sec)) != NULL) {
160 gelf_getshdr(sec, &shdr);
161
162 if ((addr >= shdr.sh_addr) &&
163 (addr < (shdr.sh_addr + shdr.sh_size)))
164 return cnt;
165
166 ++cnt;
167 }
168
169 return -1;
170 }
171
172 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
173 GElf_Shdr *shp, const char *name, size_t *idx)
174 {
175 Elf_Scn *sec = NULL;
176 size_t cnt = 1;
177
178 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
179 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
180 return NULL;
181
182 while ((sec = elf_nextscn(elf, sec)) != NULL) {
183 char *str;
184
185 gelf_getshdr(sec, shp);
186 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
187 if (str && !strcmp(name, str)) {
188 if (idx)
189 *idx = cnt;
190 return sec;
191 }
192 ++cnt;
193 }
194
195 return NULL;
196 }
197
198 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
199 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
200 idx < nr_entries; \
201 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
202
203 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
204 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
205 idx < nr_entries; \
206 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
207
208 /*
209 * We need to check if we have a .dynsym, so that we can handle the
210 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
211 * .dynsym or .symtab).
212 * And always look at the original dso, not at debuginfo packages, that
213 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
214 */
215 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
216 symbol_filter_t filter)
217 {
218 uint32_t nr_rel_entries, idx;
219 GElf_Sym sym;
220 u64 plt_offset;
221 GElf_Shdr shdr_plt;
222 struct symbol *f;
223 GElf_Shdr shdr_rel_plt, shdr_dynsym;
224 Elf_Data *reldata, *syms, *symstrs;
225 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
226 size_t dynsym_idx;
227 GElf_Ehdr ehdr;
228 char sympltname[1024];
229 Elf *elf;
230 int nr = 0, symidx, err = 0;
231
232 if (!ss->dynsym)
233 return 0;
234
235 elf = ss->elf;
236 ehdr = ss->ehdr;
237
238 scn_dynsym = ss->dynsym;
239 shdr_dynsym = ss->dynshdr;
240 dynsym_idx = ss->dynsym_idx;
241
242 if (scn_dynsym == NULL)
243 goto out_elf_end;
244
245 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
246 ".rela.plt", NULL);
247 if (scn_plt_rel == NULL) {
248 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
249 ".rel.plt", NULL);
250 if (scn_plt_rel == NULL)
251 goto out_elf_end;
252 }
253
254 err = -1;
255
256 if (shdr_rel_plt.sh_link != dynsym_idx)
257 goto out_elf_end;
258
259 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
260 goto out_elf_end;
261
262 /*
263 * Fetch the relocation section to find the idxes to the GOT
264 * and the symbols in the .dynsym they refer to.
265 */
266 reldata = elf_getdata(scn_plt_rel, NULL);
267 if (reldata == NULL)
268 goto out_elf_end;
269
270 syms = elf_getdata(scn_dynsym, NULL);
271 if (syms == NULL)
272 goto out_elf_end;
273
274 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
275 if (scn_symstrs == NULL)
276 goto out_elf_end;
277
278 symstrs = elf_getdata(scn_symstrs, NULL);
279 if (symstrs == NULL)
280 goto out_elf_end;
281
282 if (symstrs->d_size == 0)
283 goto out_elf_end;
284
285 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
286 plt_offset = shdr_plt.sh_offset;
287
288 if (shdr_rel_plt.sh_type == SHT_RELA) {
289 GElf_Rela pos_mem, *pos;
290
291 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
292 nr_rel_entries) {
293 symidx = GELF_R_SYM(pos->r_info);
294 plt_offset += shdr_plt.sh_entsize;
295 gelf_getsym(syms, symidx, &sym);
296 snprintf(sympltname, sizeof(sympltname),
297 "%s@plt", elf_sym__name(&sym, symstrs));
298
299 f = symbol__new(plt_offset, shdr_plt.sh_entsize,
300 STB_GLOBAL, sympltname);
301 if (!f)
302 goto out_elf_end;
303
304 if (filter && filter(map, f))
305 symbol__delete(f);
306 else {
307 symbols__insert(&dso->symbols[map->type], f);
308 ++nr;
309 }
310 }
311 } else if (shdr_rel_plt.sh_type == SHT_REL) {
312 GElf_Rel pos_mem, *pos;
313 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
314 nr_rel_entries) {
315 symidx = GELF_R_SYM(pos->r_info);
316 plt_offset += shdr_plt.sh_entsize;
317 gelf_getsym(syms, symidx, &sym);
318 snprintf(sympltname, sizeof(sympltname),
319 "%s@plt", elf_sym__name(&sym, symstrs));
320
321 f = symbol__new(plt_offset, shdr_plt.sh_entsize,
322 STB_GLOBAL, sympltname);
323 if (!f)
324 goto out_elf_end;
325
326 if (filter && filter(map, f))
327 symbol__delete(f);
328 else {
329 symbols__insert(&dso->symbols[map->type], f);
330 ++nr;
331 }
332 }
333 }
334
335 err = 0;
336 out_elf_end:
337 if (err == 0)
338 return nr;
339 pr_debug("%s: problems reading %s PLT info.\n",
340 __func__, dso->long_name);
341 return 0;
342 }
343
344 /*
345 * Align offset to 4 bytes as needed for note name and descriptor data.
346 */
347 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
348
349 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
350 {
351 int err = -1;
352 GElf_Ehdr ehdr;
353 GElf_Shdr shdr;
354 Elf_Data *data;
355 Elf_Scn *sec;
356 Elf_Kind ek;
357 void *ptr;
358
359 if (size < BUILD_ID_SIZE)
360 goto out;
361
362 ek = elf_kind(elf);
363 if (ek != ELF_K_ELF)
364 goto out;
365
366 if (gelf_getehdr(elf, &ehdr) == NULL) {
367 pr_err("%s: cannot get elf header.\n", __func__);
368 goto out;
369 }
370
371 /*
372 * Check following sections for notes:
373 * '.note.gnu.build-id'
374 * '.notes'
375 * '.note' (VDSO specific)
376 */
377 do {
378 sec = elf_section_by_name(elf, &ehdr, &shdr,
379 ".note.gnu.build-id", NULL);
380 if (sec)
381 break;
382
383 sec = elf_section_by_name(elf, &ehdr, &shdr,
384 ".notes", NULL);
385 if (sec)
386 break;
387
388 sec = elf_section_by_name(elf, &ehdr, &shdr,
389 ".note", NULL);
390 if (sec)
391 break;
392
393 return err;
394
395 } while (0);
396
397 data = elf_getdata(sec, NULL);
398 if (data == NULL)
399 goto out;
400
401 ptr = data->d_buf;
402 while (ptr < (data->d_buf + data->d_size)) {
403 GElf_Nhdr *nhdr = ptr;
404 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
405 descsz = NOTE_ALIGN(nhdr->n_descsz);
406 const char *name;
407
408 ptr += sizeof(*nhdr);
409 name = ptr;
410 ptr += namesz;
411 if (nhdr->n_type == NT_GNU_BUILD_ID &&
412 nhdr->n_namesz == sizeof("GNU")) {
413 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
414 size_t sz = min(size, descsz);
415 memcpy(bf, ptr, sz);
416 memset(bf + sz, 0, size - sz);
417 err = descsz;
418 break;
419 }
420 }
421 ptr += descsz;
422 }
423
424 out:
425 return err;
426 }
427
428 int filename__read_build_id(const char *filename, void *bf, size_t size)
429 {
430 int fd, err = -1;
431 Elf *elf;
432
433 if (size < BUILD_ID_SIZE)
434 goto out;
435
436 fd = open(filename, O_RDONLY);
437 if (fd < 0)
438 goto out;
439
440 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
441 if (elf == NULL) {
442 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
443 goto out_close;
444 }
445
446 err = elf_read_build_id(elf, bf, size);
447
448 elf_end(elf);
449 out_close:
450 close(fd);
451 out:
452 return err;
453 }
454
455 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
456 {
457 int fd, err = -1;
458
459 if (size < BUILD_ID_SIZE)
460 goto out;
461
462 fd = open(filename, O_RDONLY);
463 if (fd < 0)
464 goto out;
465
466 while (1) {
467 char bf[BUFSIZ];
468 GElf_Nhdr nhdr;
469 size_t namesz, descsz;
470
471 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
472 break;
473
474 namesz = NOTE_ALIGN(nhdr.n_namesz);
475 descsz = NOTE_ALIGN(nhdr.n_descsz);
476 if (nhdr.n_type == NT_GNU_BUILD_ID &&
477 nhdr.n_namesz == sizeof("GNU")) {
478 if (read(fd, bf, namesz) != (ssize_t)namesz)
479 break;
480 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
481 size_t sz = min(descsz, size);
482 if (read(fd, build_id, sz) == (ssize_t)sz) {
483 memset(build_id + sz, 0, size - sz);
484 err = 0;
485 break;
486 }
487 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
488 break;
489 } else {
490 int n = namesz + descsz;
491 if (read(fd, bf, n) != n)
492 break;
493 }
494 }
495 close(fd);
496 out:
497 return err;
498 }
499
500 int filename__read_debuglink(const char *filename, char *debuglink,
501 size_t size)
502 {
503 int fd, err = -1;
504 Elf *elf;
505 GElf_Ehdr ehdr;
506 GElf_Shdr shdr;
507 Elf_Data *data;
508 Elf_Scn *sec;
509 Elf_Kind ek;
510
511 fd = open(filename, O_RDONLY);
512 if (fd < 0)
513 goto out;
514
515 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
516 if (elf == NULL) {
517 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
518 goto out_close;
519 }
520
521 ek = elf_kind(elf);
522 if (ek != ELF_K_ELF)
523 goto out_elf_end;
524
525 if (gelf_getehdr(elf, &ehdr) == NULL) {
526 pr_err("%s: cannot get elf header.\n", __func__);
527 goto out_elf_end;
528 }
529
530 sec = elf_section_by_name(elf, &ehdr, &shdr,
531 ".gnu_debuglink", NULL);
532 if (sec == NULL)
533 goto out_elf_end;
534
535 data = elf_getdata(sec, NULL);
536 if (data == NULL)
537 goto out_elf_end;
538
539 /* the start of this section is a zero-terminated string */
540 strncpy(debuglink, data->d_buf, size);
541
542 err = 0;
543
544 out_elf_end:
545 elf_end(elf);
546 out_close:
547 close(fd);
548 out:
549 return err;
550 }
551
552 static int dso__swap_init(struct dso *dso, unsigned char eidata)
553 {
554 static unsigned int const endian = 1;
555
556 dso->needs_swap = DSO_SWAP__NO;
557
558 switch (eidata) {
559 case ELFDATA2LSB:
560 /* We are big endian, DSO is little endian. */
561 if (*(unsigned char const *)&endian != 1)
562 dso->needs_swap = DSO_SWAP__YES;
563 break;
564
565 case ELFDATA2MSB:
566 /* We are little endian, DSO is big endian. */
567 if (*(unsigned char const *)&endian != 0)
568 dso->needs_swap = DSO_SWAP__YES;
569 break;
570
571 default:
572 pr_err("unrecognized DSO data encoding %d\n", eidata);
573 return -EINVAL;
574 }
575
576 return 0;
577 }
578
579 static int decompress_kmodule(struct dso *dso, const char *name,
580 enum dso_binary_type type)
581 {
582 int fd = -1;
583 char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
584 struct kmod_path m;
585
586 if (type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
587 type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP &&
588 type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
589 return -1;
590
591 if (type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
592 name = dso->long_name;
593
594 if (kmod_path__parse_ext(&m, name) || !m.comp)
595 return -1;
596
597 fd = mkstemp(tmpbuf);
598 if (fd < 0) {
599 dso->load_errno = errno;
600 goto out;
601 }
602
603 if (!decompress_to_file(m.ext, name, fd)) {
604 dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
605 close(fd);
606 fd = -1;
607 }
608
609 unlink(tmpbuf);
610
611 out:
612 free(m.ext);
613 return fd;
614 }
615
616 bool symsrc__possibly_runtime(struct symsrc *ss)
617 {
618 return ss->dynsym || ss->opdsec;
619 }
620
621 bool symsrc__has_symtab(struct symsrc *ss)
622 {
623 return ss->symtab != NULL;
624 }
625
626 void symsrc__destroy(struct symsrc *ss)
627 {
628 zfree(&ss->name);
629 elf_end(ss->elf);
630 close(ss->fd);
631 }
632
633 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
634 {
635 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
636 }
637
638 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
639 enum dso_binary_type type)
640 {
641 int err = -1;
642 GElf_Ehdr ehdr;
643 Elf *elf;
644 int fd;
645
646 if (dso__needs_decompress(dso)) {
647 fd = decompress_kmodule(dso, name, type);
648 if (fd < 0)
649 return -1;
650 } else {
651 fd = open(name, O_RDONLY);
652 if (fd < 0) {
653 dso->load_errno = errno;
654 return -1;
655 }
656 }
657
658 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
659 if (elf == NULL) {
660 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
661 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
662 goto out_close;
663 }
664
665 if (gelf_getehdr(elf, &ehdr) == NULL) {
666 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
667 pr_debug("%s: cannot get elf header.\n", __func__);
668 goto out_elf_end;
669 }
670
671 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
672 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
673 goto out_elf_end;
674 }
675
676 /* Always reject images with a mismatched build-id: */
677 if (dso->has_build_id) {
678 u8 build_id[BUILD_ID_SIZE];
679
680 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
681 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
682 goto out_elf_end;
683 }
684
685 if (!dso__build_id_equal(dso, build_id)) {
686 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
687 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
688 goto out_elf_end;
689 }
690 }
691
692 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
693
694 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
695 NULL);
696 if (ss->symshdr.sh_type != SHT_SYMTAB)
697 ss->symtab = NULL;
698
699 ss->dynsym_idx = 0;
700 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
701 &ss->dynsym_idx);
702 if (ss->dynshdr.sh_type != SHT_DYNSYM)
703 ss->dynsym = NULL;
704
705 ss->opdidx = 0;
706 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
707 &ss->opdidx);
708 if (ss->opdshdr.sh_type != SHT_PROGBITS)
709 ss->opdsec = NULL;
710
711 if (dso->kernel == DSO_TYPE_USER) {
712 GElf_Shdr shdr;
713 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
714 ehdr.e_type == ET_REL ||
715 dso__is_vdso(dso) ||
716 elf_section_by_name(elf, &ehdr, &shdr,
717 ".gnu.prelink_undo",
718 NULL) != NULL);
719 } else {
720 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
721 }
722
723 ss->name = strdup(name);
724 if (!ss->name) {
725 dso->load_errno = errno;
726 goto out_elf_end;
727 }
728
729 ss->elf = elf;
730 ss->fd = fd;
731 ss->ehdr = ehdr;
732 ss->type = type;
733
734 return 0;
735
736 out_elf_end:
737 elf_end(elf);
738 out_close:
739 close(fd);
740 return err;
741 }
742
743 /**
744 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
745 * @kmap: kernel maps and relocation reference symbol
746 *
747 * This function returns %true if we are dealing with the kernel maps and the
748 * relocation reference symbol has not yet been found. Otherwise %false is
749 * returned.
750 */
751 static bool ref_reloc_sym_not_found(struct kmap *kmap)
752 {
753 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
754 !kmap->ref_reloc_sym->unrelocated_addr;
755 }
756
757 /**
758 * ref_reloc - kernel relocation offset.
759 * @kmap: kernel maps and relocation reference symbol
760 *
761 * This function returns the offset of kernel addresses as determined by using
762 * the relocation reference symbol i.e. if the kernel has not been relocated
763 * then the return value is zero.
764 */
765 static u64 ref_reloc(struct kmap *kmap)
766 {
767 if (kmap && kmap->ref_reloc_sym &&
768 kmap->ref_reloc_sym->unrelocated_addr)
769 return kmap->ref_reloc_sym->addr -
770 kmap->ref_reloc_sym->unrelocated_addr;
771 return 0;
772 }
773
774 static bool want_demangle(bool is_kernel_sym)
775 {
776 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
777 }
778
779 void __weak arch__elf_sym_adjust(GElf_Sym *sym __maybe_unused) { }
780
781 int dso__load_sym(struct dso *dso, struct map *map,
782 struct symsrc *syms_ss, struct symsrc *runtime_ss,
783 symbol_filter_t filter, int kmodule)
784 {
785 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
786 struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
787 struct map *curr_map = map;
788 struct dso *curr_dso = dso;
789 Elf_Data *symstrs, *secstrs;
790 uint32_t nr_syms;
791 int err = -1;
792 uint32_t idx;
793 GElf_Ehdr ehdr;
794 GElf_Shdr shdr;
795 Elf_Data *syms, *opddata = NULL;
796 GElf_Sym sym;
797 Elf_Scn *sec, *sec_strndx;
798 Elf *elf;
799 int nr = 0;
800 bool remap_kernel = false, adjust_kernel_syms = false;
801
802 if (kmap && !kmaps)
803 return -1;
804
805 dso->symtab_type = syms_ss->type;
806 dso->is_64_bit = syms_ss->is_64_bit;
807 dso->rel = syms_ss->ehdr.e_type == ET_REL;
808
809 /*
810 * Modules may already have symbols from kallsyms, but those symbols
811 * have the wrong values for the dso maps, so remove them.
812 */
813 if (kmodule && syms_ss->symtab)
814 symbols__delete(&dso->symbols[map->type]);
815
816 if (!syms_ss->symtab) {
817 /*
818 * If the vmlinux is stripped, fail so we will fall back
819 * to using kallsyms. The vmlinux runtime symbols aren't
820 * of much use.
821 */
822 if (dso->kernel)
823 goto out_elf_end;
824
825 syms_ss->symtab = syms_ss->dynsym;
826 syms_ss->symshdr = syms_ss->dynshdr;
827 }
828
829 elf = syms_ss->elf;
830 ehdr = syms_ss->ehdr;
831 sec = syms_ss->symtab;
832 shdr = syms_ss->symshdr;
833
834 if (runtime_ss->opdsec)
835 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
836
837 syms = elf_getdata(sec, NULL);
838 if (syms == NULL)
839 goto out_elf_end;
840
841 sec = elf_getscn(elf, shdr.sh_link);
842 if (sec == NULL)
843 goto out_elf_end;
844
845 symstrs = elf_getdata(sec, NULL);
846 if (symstrs == NULL)
847 goto out_elf_end;
848
849 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
850 if (sec_strndx == NULL)
851 goto out_elf_end;
852
853 secstrs = elf_getdata(sec_strndx, NULL);
854 if (secstrs == NULL)
855 goto out_elf_end;
856
857 nr_syms = shdr.sh_size / shdr.sh_entsize;
858
859 memset(&sym, 0, sizeof(sym));
860
861 /*
862 * The kernel relocation symbol is needed in advance in order to adjust
863 * kernel maps correctly.
864 */
865 if (ref_reloc_sym_not_found(kmap)) {
866 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
867 const char *elf_name = elf_sym__name(&sym, symstrs);
868
869 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
870 continue;
871 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
872 map->reloc = kmap->ref_reloc_sym->addr -
873 kmap->ref_reloc_sym->unrelocated_addr;
874 break;
875 }
876 }
877
878 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
879 /*
880 * Initial kernel and module mappings do not map to the dso. For
881 * function mappings, flag the fixups.
882 */
883 if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
884 remap_kernel = true;
885 adjust_kernel_syms = dso->adjust_symbols;
886 }
887 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
888 struct symbol *f;
889 const char *elf_name = elf_sym__name(&sym, symstrs);
890 char *demangled = NULL;
891 int is_label = elf_sym__is_label(&sym);
892 const char *section_name;
893 bool used_opd = false;
894
895 if (!is_label && !elf_sym__is_a(&sym, map->type))
896 continue;
897
898 /* Reject ARM ELF "mapping symbols": these aren't unique and
899 * don't identify functions, so will confuse the profile
900 * output: */
901 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
902 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
903 && (elf_name[2] == '\0' || elf_name[2] == '.'))
904 continue;
905 }
906
907 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
908 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
909 u64 *opd = opddata->d_buf + offset;
910 sym.st_value = DSO__SWAP(dso, u64, *opd);
911 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
912 sym.st_value);
913 used_opd = true;
914 }
915 /*
916 * When loading symbols in a data mapping, ABS symbols (which
917 * has a value of SHN_ABS in its st_shndx) failed at
918 * elf_getscn(). And it marks the loading as a failure so
919 * already loaded symbols cannot be fixed up.
920 *
921 * I'm not sure what should be done. Just ignore them for now.
922 * - Namhyung Kim
923 */
924 if (sym.st_shndx == SHN_ABS)
925 continue;
926
927 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
928 if (!sec)
929 goto out_elf_end;
930
931 gelf_getshdr(sec, &shdr);
932
933 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
934 continue;
935
936 section_name = elf_sec__name(&shdr, secstrs);
937
938 /* On ARM, symbols for thumb functions have 1 added to
939 * the symbol address as a flag - remove it */
940 if ((ehdr.e_machine == EM_ARM) &&
941 (map->type == MAP__FUNCTION) &&
942 (sym.st_value & 1))
943 --sym.st_value;
944
945 arch__elf_sym_adjust(&sym);
946
947 if (dso->kernel || kmodule) {
948 char dso_name[PATH_MAX];
949
950 /* Adjust symbol to map to file offset */
951 if (adjust_kernel_syms)
952 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
953
954 if (strcmp(section_name,
955 (curr_dso->short_name +
956 dso->short_name_len)) == 0)
957 goto new_symbol;
958
959 if (strcmp(section_name, ".text") == 0) {
960 /*
961 * The initial kernel mapping is based on
962 * kallsyms and identity maps. Overwrite it to
963 * map to the kernel dso.
964 */
965 if (remap_kernel && dso->kernel) {
966 remap_kernel = false;
967 map->start = shdr.sh_addr +
968 ref_reloc(kmap);
969 map->end = map->start + shdr.sh_size;
970 map->pgoff = shdr.sh_offset;
971 map->map_ip = map__map_ip;
972 map->unmap_ip = map__unmap_ip;
973 /* Ensure maps are correctly ordered */
974 if (kmaps) {
975 map__get(map);
976 map_groups__remove(kmaps, map);
977 map_groups__insert(kmaps, map);
978 map__put(map);
979 }
980 }
981
982 /*
983 * The initial module mapping is based on
984 * /proc/modules mapped to offset zero.
985 * Overwrite it to map to the module dso.
986 */
987 if (remap_kernel && kmodule) {
988 remap_kernel = false;
989 map->pgoff = shdr.sh_offset;
990 }
991
992 curr_map = map;
993 curr_dso = dso;
994 goto new_symbol;
995 }
996
997 if (!kmap)
998 goto new_symbol;
999
1000 snprintf(dso_name, sizeof(dso_name),
1001 "%s%s", dso->short_name, section_name);
1002
1003 curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1004 if (curr_map == NULL) {
1005 u64 start = sym.st_value;
1006
1007 if (kmodule)
1008 start += map->start + shdr.sh_offset;
1009
1010 curr_dso = dso__new(dso_name);
1011 if (curr_dso == NULL)
1012 goto out_elf_end;
1013 curr_dso->kernel = dso->kernel;
1014 curr_dso->long_name = dso->long_name;
1015 curr_dso->long_name_len = dso->long_name_len;
1016 curr_map = map__new2(start, curr_dso,
1017 map->type);
1018 if (curr_map == NULL) {
1019 dso__put(curr_dso);
1020 goto out_elf_end;
1021 }
1022 if (adjust_kernel_syms) {
1023 curr_map->start = shdr.sh_addr +
1024 ref_reloc(kmap);
1025 curr_map->end = curr_map->start +
1026 shdr.sh_size;
1027 curr_map->pgoff = shdr.sh_offset;
1028 } else {
1029 curr_map->map_ip = identity__map_ip;
1030 curr_map->unmap_ip = identity__map_ip;
1031 }
1032 curr_dso->symtab_type = dso->symtab_type;
1033 map_groups__insert(kmaps, curr_map);
1034 dsos__add(&map->groups->machine->dsos, curr_dso);
1035 dso__set_loaded(curr_dso, map->type);
1036 } else
1037 curr_dso = curr_map->dso;
1038
1039 goto new_symbol;
1040 }
1041
1042 if ((used_opd && runtime_ss->adjust_symbols)
1043 || (!used_opd && syms_ss->adjust_symbols)) {
1044 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1045 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1046 (u64)sym.st_value, (u64)shdr.sh_addr,
1047 (u64)shdr.sh_offset);
1048 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1049 }
1050 new_symbol:
1051 /*
1052 * We need to figure out if the object was created from C++ sources
1053 * DWARF DW_compile_unit has this, but we don't always have access
1054 * to it...
1055 */
1056 if (want_demangle(dso->kernel || kmodule)) {
1057 int demangle_flags = DMGL_NO_OPTS;
1058 if (verbose)
1059 demangle_flags = DMGL_PARAMS | DMGL_ANSI;
1060
1061 demangled = bfd_demangle(NULL, elf_name, demangle_flags);
1062 if (demangled != NULL)
1063 elf_name = demangled;
1064 }
1065 f = symbol__new(sym.st_value, sym.st_size,
1066 GELF_ST_BIND(sym.st_info), elf_name);
1067 free(demangled);
1068 if (!f)
1069 goto out_elf_end;
1070
1071 if (filter && filter(curr_map, f))
1072 symbol__delete(f);
1073 else {
1074 symbols__insert(&curr_dso->symbols[curr_map->type], f);
1075 nr++;
1076 }
1077 }
1078
1079 /*
1080 * For misannotated, zeroed, ASM function sizes.
1081 */
1082 if (nr > 0) {
1083 if (!symbol_conf.allow_aliases)
1084 symbols__fixup_duplicate(&dso->symbols[map->type]);
1085 symbols__fixup_end(&dso->symbols[map->type]);
1086 if (kmap) {
1087 /*
1088 * We need to fixup this here too because we create new
1089 * maps here, for things like vsyscall sections.
1090 */
1091 __map_groups__fixup_end(kmaps, map->type);
1092 }
1093 }
1094 err = nr;
1095 out_elf_end:
1096 return err;
1097 }
1098
1099 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1100 {
1101 GElf_Phdr phdr;
1102 size_t i, phdrnum;
1103 int err;
1104 u64 sz;
1105
1106 if (elf_getphdrnum(elf, &phdrnum))
1107 return -1;
1108
1109 for (i = 0; i < phdrnum; i++) {
1110 if (gelf_getphdr(elf, i, &phdr) == NULL)
1111 return -1;
1112 if (phdr.p_type != PT_LOAD)
1113 continue;
1114 if (exe) {
1115 if (!(phdr.p_flags & PF_X))
1116 continue;
1117 } else {
1118 if (!(phdr.p_flags & PF_R))
1119 continue;
1120 }
1121 sz = min(phdr.p_memsz, phdr.p_filesz);
1122 if (!sz)
1123 continue;
1124 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1125 if (err)
1126 return err;
1127 }
1128 return 0;
1129 }
1130
1131 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1132 bool *is_64_bit)
1133 {
1134 int err;
1135 Elf *elf;
1136
1137 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1138 if (elf == NULL)
1139 return -1;
1140
1141 if (is_64_bit)
1142 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1143
1144 err = elf_read_maps(elf, exe, mapfn, data);
1145
1146 elf_end(elf);
1147 return err;
1148 }
1149
1150 enum dso_type dso__type_fd(int fd)
1151 {
1152 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1153 GElf_Ehdr ehdr;
1154 Elf_Kind ek;
1155 Elf *elf;
1156
1157 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1158 if (elf == NULL)
1159 goto out;
1160
1161 ek = elf_kind(elf);
1162 if (ek != ELF_K_ELF)
1163 goto out_end;
1164
1165 if (gelf_getclass(elf) == ELFCLASS64) {
1166 dso_type = DSO__TYPE_64BIT;
1167 goto out_end;
1168 }
1169
1170 if (gelf_getehdr(elf, &ehdr) == NULL)
1171 goto out_end;
1172
1173 if (ehdr.e_machine == EM_X86_64)
1174 dso_type = DSO__TYPE_X32BIT;
1175 else
1176 dso_type = DSO__TYPE_32BIT;
1177 out_end:
1178 elf_end(elf);
1179 out:
1180 return dso_type;
1181 }
1182
1183 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1184 {
1185 ssize_t r;
1186 size_t n;
1187 int err = -1;
1188 char *buf = malloc(page_size);
1189
1190 if (buf == NULL)
1191 return -1;
1192
1193 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1194 goto out;
1195
1196 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1197 goto out;
1198
1199 while (len) {
1200 n = page_size;
1201 if (len < n)
1202 n = len;
1203 /* Use read because mmap won't work on proc files */
1204 r = read(from, buf, n);
1205 if (r < 0)
1206 goto out;
1207 if (!r)
1208 break;
1209 n = r;
1210 r = write(to, buf, n);
1211 if (r < 0)
1212 goto out;
1213 if ((size_t)r != n)
1214 goto out;
1215 len -= n;
1216 }
1217
1218 err = 0;
1219 out:
1220 free(buf);
1221 return err;
1222 }
1223
1224 struct kcore {
1225 int fd;
1226 int elfclass;
1227 Elf *elf;
1228 GElf_Ehdr ehdr;
1229 };
1230
1231 static int kcore__open(struct kcore *kcore, const char *filename)
1232 {
1233 GElf_Ehdr *ehdr;
1234
1235 kcore->fd = open(filename, O_RDONLY);
1236 if (kcore->fd == -1)
1237 return -1;
1238
1239 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1240 if (!kcore->elf)
1241 goto out_close;
1242
1243 kcore->elfclass = gelf_getclass(kcore->elf);
1244 if (kcore->elfclass == ELFCLASSNONE)
1245 goto out_end;
1246
1247 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1248 if (!ehdr)
1249 goto out_end;
1250
1251 return 0;
1252
1253 out_end:
1254 elf_end(kcore->elf);
1255 out_close:
1256 close(kcore->fd);
1257 return -1;
1258 }
1259
1260 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1261 bool temp)
1262 {
1263 GElf_Ehdr *ehdr;
1264
1265 kcore->elfclass = elfclass;
1266
1267 if (temp)
1268 kcore->fd = mkstemp(filename);
1269 else
1270 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1271 if (kcore->fd == -1)
1272 return -1;
1273
1274 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1275 if (!kcore->elf)
1276 goto out_close;
1277
1278 if (!gelf_newehdr(kcore->elf, elfclass))
1279 goto out_end;
1280
1281 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1282 if (!ehdr)
1283 goto out_end;
1284
1285 return 0;
1286
1287 out_end:
1288 elf_end(kcore->elf);
1289 out_close:
1290 close(kcore->fd);
1291 unlink(filename);
1292 return -1;
1293 }
1294
1295 static void kcore__close(struct kcore *kcore)
1296 {
1297 elf_end(kcore->elf);
1298 close(kcore->fd);
1299 }
1300
1301 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1302 {
1303 GElf_Ehdr *ehdr = &to->ehdr;
1304 GElf_Ehdr *kehdr = &from->ehdr;
1305
1306 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1307 ehdr->e_type = kehdr->e_type;
1308 ehdr->e_machine = kehdr->e_machine;
1309 ehdr->e_version = kehdr->e_version;
1310 ehdr->e_entry = 0;
1311 ehdr->e_shoff = 0;
1312 ehdr->e_flags = kehdr->e_flags;
1313 ehdr->e_phnum = count;
1314 ehdr->e_shentsize = 0;
1315 ehdr->e_shnum = 0;
1316 ehdr->e_shstrndx = 0;
1317
1318 if (from->elfclass == ELFCLASS32) {
1319 ehdr->e_phoff = sizeof(Elf32_Ehdr);
1320 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
1321 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1322 } else {
1323 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1324 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1325 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1326 }
1327
1328 if (!gelf_update_ehdr(to->elf, ehdr))
1329 return -1;
1330
1331 if (!gelf_newphdr(to->elf, count))
1332 return -1;
1333
1334 return 0;
1335 }
1336
1337 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1338 u64 addr, u64 len)
1339 {
1340 GElf_Phdr gphdr;
1341 GElf_Phdr *phdr;
1342
1343 phdr = gelf_getphdr(kcore->elf, idx, &gphdr);
1344 if (!phdr)
1345 return -1;
1346
1347 phdr->p_type = PT_LOAD;
1348 phdr->p_flags = PF_R | PF_W | PF_X;
1349 phdr->p_offset = offset;
1350 phdr->p_vaddr = addr;
1351 phdr->p_paddr = 0;
1352 phdr->p_filesz = len;
1353 phdr->p_memsz = len;
1354 phdr->p_align = page_size;
1355
1356 if (!gelf_update_phdr(kcore->elf, idx, phdr))
1357 return -1;
1358
1359 return 0;
1360 }
1361
1362 static off_t kcore__write(struct kcore *kcore)
1363 {
1364 return elf_update(kcore->elf, ELF_C_WRITE);
1365 }
1366
1367 struct phdr_data {
1368 off_t offset;
1369 u64 addr;
1370 u64 len;
1371 };
1372
1373 struct kcore_copy_info {
1374 u64 stext;
1375 u64 etext;
1376 u64 first_symbol;
1377 u64 last_symbol;
1378 u64 first_module;
1379 u64 last_module_symbol;
1380 struct phdr_data kernel_map;
1381 struct phdr_data modules_map;
1382 };
1383
1384 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1385 u64 start)
1386 {
1387 struct kcore_copy_info *kci = arg;
1388
1389 if (!symbol_type__is_a(type, MAP__FUNCTION))
1390 return 0;
1391
1392 if (strchr(name, '[')) {
1393 if (start > kci->last_module_symbol)
1394 kci->last_module_symbol = start;
1395 return 0;
1396 }
1397
1398 if (!kci->first_symbol || start < kci->first_symbol)
1399 kci->first_symbol = start;
1400
1401 if (!kci->last_symbol || start > kci->last_symbol)
1402 kci->last_symbol = start;
1403
1404 if (!strcmp(name, "_stext")) {
1405 kci->stext = start;
1406 return 0;
1407 }
1408
1409 if (!strcmp(name, "_etext")) {
1410 kci->etext = start;
1411 return 0;
1412 }
1413
1414 return 0;
1415 }
1416
1417 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1418 const char *dir)
1419 {
1420 char kallsyms_filename[PATH_MAX];
1421
1422 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1423
1424 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1425 return -1;
1426
1427 if (kallsyms__parse(kallsyms_filename, kci,
1428 kcore_copy__process_kallsyms) < 0)
1429 return -1;
1430
1431 return 0;
1432 }
1433
1434 static int kcore_copy__process_modules(void *arg,
1435 const char *name __maybe_unused,
1436 u64 start)
1437 {
1438 struct kcore_copy_info *kci = arg;
1439
1440 if (!kci->first_module || start < kci->first_module)
1441 kci->first_module = start;
1442
1443 return 0;
1444 }
1445
1446 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1447 const char *dir)
1448 {
1449 char modules_filename[PATH_MAX];
1450
1451 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1452
1453 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1454 return -1;
1455
1456 if (modules__parse(modules_filename, kci,
1457 kcore_copy__process_modules) < 0)
1458 return -1;
1459
1460 return 0;
1461 }
1462
1463 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1464 u64 s, u64 e)
1465 {
1466 if (p->addr || s < start || s >= end)
1467 return;
1468
1469 p->addr = s;
1470 p->offset = (s - start) + pgoff;
1471 p->len = e < end ? e - s : end - s;
1472 }
1473
1474 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1475 {
1476 struct kcore_copy_info *kci = data;
1477 u64 end = start + len;
1478
1479 kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1480 kci->etext);
1481
1482 kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1483 kci->last_module_symbol);
1484
1485 return 0;
1486 }
1487
1488 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1489 {
1490 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1491 return -1;
1492
1493 return 0;
1494 }
1495
1496 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1497 Elf *elf)
1498 {
1499 if (kcore_copy__parse_kallsyms(kci, dir))
1500 return -1;
1501
1502 if (kcore_copy__parse_modules(kci, dir))
1503 return -1;
1504
1505 if (kci->stext)
1506 kci->stext = round_down(kci->stext, page_size);
1507 else
1508 kci->stext = round_down(kci->first_symbol, page_size);
1509
1510 if (kci->etext) {
1511 kci->etext = round_up(kci->etext, page_size);
1512 } else if (kci->last_symbol) {
1513 kci->etext = round_up(kci->last_symbol, page_size);
1514 kci->etext += page_size;
1515 }
1516
1517 kci->first_module = round_down(kci->first_module, page_size);
1518
1519 if (kci->last_module_symbol) {
1520 kci->last_module_symbol = round_up(kci->last_module_symbol,
1521 page_size);
1522 kci->last_module_symbol += page_size;
1523 }
1524
1525 if (!kci->stext || !kci->etext)
1526 return -1;
1527
1528 if (kci->first_module && !kci->last_module_symbol)
1529 return -1;
1530
1531 return kcore_copy__read_maps(kci, elf);
1532 }
1533
1534 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1535 const char *name)
1536 {
1537 char from_filename[PATH_MAX];
1538 char to_filename[PATH_MAX];
1539
1540 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1541 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1542
1543 return copyfile_mode(from_filename, to_filename, 0400);
1544 }
1545
1546 static int kcore_copy__unlink(const char *dir, const char *name)
1547 {
1548 char filename[PATH_MAX];
1549
1550 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1551
1552 return unlink(filename);
1553 }
1554
1555 static int kcore_copy__compare_fds(int from, int to)
1556 {
1557 char *buf_from;
1558 char *buf_to;
1559 ssize_t ret;
1560 size_t len;
1561 int err = -1;
1562
1563 buf_from = malloc(page_size);
1564 buf_to = malloc(page_size);
1565 if (!buf_from || !buf_to)
1566 goto out;
1567
1568 while (1) {
1569 /* Use read because mmap won't work on proc files */
1570 ret = read(from, buf_from, page_size);
1571 if (ret < 0)
1572 goto out;
1573
1574 if (!ret)
1575 break;
1576
1577 len = ret;
1578
1579 if (readn(to, buf_to, len) != (int)len)
1580 goto out;
1581
1582 if (memcmp(buf_from, buf_to, len))
1583 goto out;
1584 }
1585
1586 err = 0;
1587 out:
1588 free(buf_to);
1589 free(buf_from);
1590 return err;
1591 }
1592
1593 static int kcore_copy__compare_files(const char *from_filename,
1594 const char *to_filename)
1595 {
1596 int from, to, err = -1;
1597
1598 from = open(from_filename, O_RDONLY);
1599 if (from < 0)
1600 return -1;
1601
1602 to = open(to_filename, O_RDONLY);
1603 if (to < 0)
1604 goto out_close_from;
1605
1606 err = kcore_copy__compare_fds(from, to);
1607
1608 close(to);
1609 out_close_from:
1610 close(from);
1611 return err;
1612 }
1613
1614 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1615 const char *name)
1616 {
1617 char from_filename[PATH_MAX];
1618 char to_filename[PATH_MAX];
1619
1620 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1621 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1622
1623 return kcore_copy__compare_files(from_filename, to_filename);
1624 }
1625
1626 /**
1627 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1628 * @from_dir: from directory
1629 * @to_dir: to directory
1630 *
1631 * This function copies kallsyms, modules and kcore files from one directory to
1632 * another. kallsyms and modules are copied entirely. Only code segments are
1633 * copied from kcore. It is assumed that two segments suffice: one for the
1634 * kernel proper and one for all the modules. The code segments are determined
1635 * from kallsyms and modules files. The kernel map starts at _stext or the
1636 * lowest function symbol, and ends at _etext or the highest function symbol.
1637 * The module map starts at the lowest module address and ends at the highest
1638 * module symbol. Start addresses are rounded down to the nearest page. End
1639 * addresses are rounded up to the nearest page. An extra page is added to the
1640 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1641 * symbol too. Because it contains only code sections, the resulting kcore is
1642 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1643 * is not the same for the kernel map and the modules map. That happens because
1644 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1645 * kallsyms and modules files are compared with their copies to check that
1646 * modules have not been loaded or unloaded while the copies were taking place.
1647 *
1648 * Return: %0 on success, %-1 on failure.
1649 */
1650 int kcore_copy(const char *from_dir, const char *to_dir)
1651 {
1652 struct kcore kcore;
1653 struct kcore extract;
1654 size_t count = 2;
1655 int idx = 0, err = -1;
1656 off_t offset = page_size, sz, modules_offset = 0;
1657 struct kcore_copy_info kci = { .stext = 0, };
1658 char kcore_filename[PATH_MAX];
1659 char extract_filename[PATH_MAX];
1660
1661 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1662 return -1;
1663
1664 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1665 goto out_unlink_kallsyms;
1666
1667 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1668 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1669
1670 if (kcore__open(&kcore, kcore_filename))
1671 goto out_unlink_modules;
1672
1673 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1674 goto out_kcore_close;
1675
1676 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1677 goto out_kcore_close;
1678
1679 if (!kci.modules_map.addr)
1680 count -= 1;
1681
1682 if (kcore__copy_hdr(&kcore, &extract, count))
1683 goto out_extract_close;
1684
1685 if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1686 kci.kernel_map.len))
1687 goto out_extract_close;
1688
1689 if (kci.modules_map.addr) {
1690 modules_offset = offset + kci.kernel_map.len;
1691 if (kcore__add_phdr(&extract, idx, modules_offset,
1692 kci.modules_map.addr, kci.modules_map.len))
1693 goto out_extract_close;
1694 }
1695
1696 sz = kcore__write(&extract);
1697 if (sz < 0 || sz > offset)
1698 goto out_extract_close;
1699
1700 if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1701 kci.kernel_map.len))
1702 goto out_extract_close;
1703
1704 if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1705 extract.fd, modules_offset,
1706 kci.modules_map.len))
1707 goto out_extract_close;
1708
1709 if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1710 goto out_extract_close;
1711
1712 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1713 goto out_extract_close;
1714
1715 err = 0;
1716
1717 out_extract_close:
1718 kcore__close(&extract);
1719 if (err)
1720 unlink(extract_filename);
1721 out_kcore_close:
1722 kcore__close(&kcore);
1723 out_unlink_modules:
1724 if (err)
1725 kcore_copy__unlink(to_dir, "modules");
1726 out_unlink_kallsyms:
1727 if (err)
1728 kcore_copy__unlink(to_dir, "kallsyms");
1729
1730 return err;
1731 }
1732
1733 int kcore_extract__create(struct kcore_extract *kce)
1734 {
1735 struct kcore kcore;
1736 struct kcore extract;
1737 size_t count = 1;
1738 int idx = 0, err = -1;
1739 off_t offset = page_size, sz;
1740
1741 if (kcore__open(&kcore, kce->kcore_filename))
1742 return -1;
1743
1744 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1745 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1746 goto out_kcore_close;
1747
1748 if (kcore__copy_hdr(&kcore, &extract, count))
1749 goto out_extract_close;
1750
1751 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1752 goto out_extract_close;
1753
1754 sz = kcore__write(&extract);
1755 if (sz < 0 || sz > offset)
1756 goto out_extract_close;
1757
1758 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1759 goto out_extract_close;
1760
1761 err = 0;
1762
1763 out_extract_close:
1764 kcore__close(&extract);
1765 if (err)
1766 unlink(kce->extract_filename);
1767 out_kcore_close:
1768 kcore__close(&kcore);
1769
1770 return err;
1771 }
1772
1773 void kcore_extract__delete(struct kcore_extract *kce)
1774 {
1775 unlink(kce->extract_filename);
1776 }
1777
1778 void symbol__elf_init(void)
1779 {
1780 elf_version(EV_CURRENT);
1781 }
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