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