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Linux 4.16-rc3
[cris-mirror.git] / tools / perf / util / symbol-elf.c
blob2de770511e705dbc8caa7a69f1398548f102720d
1 // SPDX-License-Identifier: GPL-2.0
2 #include <fcntl.h>
3 #include <stdio.h>
4 #include <errno.h>
5 #include <string.h>
6 #include <unistd.h>
7 #include <inttypes.h>
8
9 #include "symbol.h"
10 #include "demangle-java.h"
11 #include "demangle-rust.h"
12 #include "machine.h"
13 #include "vdso.h"
14 #include "debug.h"
15 #include "sane_ctype.h"
16 #include <symbol/kallsyms.h>
17
18 #ifndef EM_AARCH64
19 #define EM_AARCH64 183 /* ARM 64 bit */
20 #endif
21
22 typedef Elf64_Nhdr GElf_Nhdr;
23
24 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
25 extern char *cplus_demangle(const char *, int);
26
27 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
28 {
29 return cplus_demangle(c, i);
30 }
31 #else
32 #ifdef NO_DEMANGLE
33 static inline char *bfd_demangle(void __maybe_unused *v,
34 const char __maybe_unused *c,
35 int __maybe_unused i)
36 {
37 return NULL;
38 }
39 #else
40 #define PACKAGE 'perf'
41 #include <bfd.h>
42 #endif
43 #endif
44
45 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
46 static int elf_getphdrnum(Elf *elf, size_t *dst)
47 {
48 GElf_Ehdr gehdr;
49 GElf_Ehdr *ehdr;
50
51 ehdr = gelf_getehdr(elf, &gehdr);
52 if (!ehdr)
53 return -1;
54
55 *dst = ehdr->e_phnum;
56
57 return 0;
58 }
59 #endif
60
61 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
62 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
63 {
64 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
65 return -1;
66 }
67 #endif
68
69 #ifndef NT_GNU_BUILD_ID
70 #define NT_GNU_BUILD_ID 3
71 #endif
72
73 /**
74 * elf_symtab__for_each_symbol - iterate thru all the symbols
75 *
76 * @syms: struct elf_symtab instance to iterate
77 * @idx: uint32_t idx
78 * @sym: GElf_Sym iterator
79 */
80 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
81 for (idx = 0, gelf_getsym(syms, idx, &sym);\
82 idx < nr_syms; \
83 idx++, gelf_getsym(syms, idx, &sym))
84
85 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
86 {
87 return GELF_ST_TYPE(sym->st_info);
88 }
89
90 #ifndef STT_GNU_IFUNC
91 #define STT_GNU_IFUNC 10
92 #endif
93
94 static inline int elf_sym__is_function(const GElf_Sym *sym)
95 {
96 return (elf_sym__type(sym) == STT_FUNC ||
97 elf_sym__type(sym) == STT_GNU_IFUNC) &&
98 sym->st_name != 0 &&
99 sym->st_shndx != SHN_UNDEF;
100 }
101
102 static inline bool elf_sym__is_object(const GElf_Sym *sym)
103 {
104 return elf_sym__type(sym) == STT_OBJECT &&
105 sym->st_name != 0 &&
106 sym->st_shndx != SHN_UNDEF;
107 }
108
109 static inline int elf_sym__is_label(const GElf_Sym *sym)
110 {
111 return elf_sym__type(sym) == STT_NOTYPE &&
112 sym->st_name != 0 &&
113 sym->st_shndx != SHN_UNDEF &&
114 sym->st_shndx != SHN_ABS;
115 }
116
117 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
118 {
119 switch (type) {
120 case MAP__FUNCTION:
121 return elf_sym__is_function(sym);
122 case MAP__VARIABLE:
123 return elf_sym__is_object(sym);
124 default:
125 return false;
126 }
127 }
128
129 static inline const char *elf_sym__name(const GElf_Sym *sym,
130 const Elf_Data *symstrs)
131 {
132 return symstrs->d_buf + sym->st_name;
133 }
134
135 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
136 const Elf_Data *secstrs)
137 {
138 return secstrs->d_buf + shdr->sh_name;
139 }
140
141 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
142 const Elf_Data *secstrs)
143 {
144 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
145 }
146
147 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
148 const Elf_Data *secstrs)
149 {
150 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
151 }
152
153 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
154 enum map_type type)
155 {
156 switch (type) {
157 case MAP__FUNCTION:
158 return elf_sec__is_text(shdr, secstrs);
159 case MAP__VARIABLE:
160 return elf_sec__is_data(shdr, secstrs);
161 default:
162 return false;
163 }
164 }
165
166 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
167 {
168 Elf_Scn *sec = NULL;
169 GElf_Shdr shdr;
170 size_t cnt = 1;
171
172 while ((sec = elf_nextscn(elf, sec)) != NULL) {
173 gelf_getshdr(sec, &shdr);
174
175 if ((addr >= shdr.sh_addr) &&
176 (addr < (shdr.sh_addr + shdr.sh_size)))
177 return cnt;
178
179 ++cnt;
180 }
181
182 return -1;
183 }
184
185 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
186 GElf_Shdr *shp, const char *name, size_t *idx)
187 {
188 Elf_Scn *sec = NULL;
189 size_t cnt = 1;
190
191 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
192 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
193 return NULL;
194
195 while ((sec = elf_nextscn(elf, sec)) != NULL) {
196 char *str;
197
198 gelf_getshdr(sec, shp);
199 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
200 if (str && !strcmp(name, str)) {
201 if (idx)
202 *idx = cnt;
203 return sec;
204 }
205 ++cnt;
206 }
207
208 return NULL;
209 }
210
211 static bool want_demangle(bool is_kernel_sym)
212 {
213 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
214 }
215
216 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
217 {
218 int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
219 char *demangled = NULL;
220
221 /*
222 * We need to figure out if the object was created from C++ sources
223 * DWARF DW_compile_unit has this, but we don't always have access
224 * to it...
225 */
226 if (!want_demangle(dso->kernel || kmodule))
227 return demangled;
228
229 demangled = bfd_demangle(NULL, elf_name, demangle_flags);
230 if (demangled == NULL)
231 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
232 else if (rust_is_mangled(demangled))
233 /*
234 * Input to Rust demangling is the BFD-demangled
235 * name which it Rust-demangles in place.
236 */
237 rust_demangle_sym(demangled);
238
239 return demangled;
240 }
241
242 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
243 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
244 idx < nr_entries; \
245 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
246
247 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
248 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
249 idx < nr_entries; \
250 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
251
252 /*
253 * We need to check if we have a .dynsym, so that we can handle the
254 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
255 * .dynsym or .symtab).
256 * And always look at the original dso, not at debuginfo packages, that
257 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
258 */
259 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map)
260 {
261 uint32_t nr_rel_entries, idx;
262 GElf_Sym sym;
263 u64 plt_offset, plt_header_size, plt_entry_size;
264 GElf_Shdr shdr_plt;
265 struct symbol *f;
266 GElf_Shdr shdr_rel_plt, shdr_dynsym;
267 Elf_Data *reldata, *syms, *symstrs;
268 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
269 size_t dynsym_idx;
270 GElf_Ehdr ehdr;
271 char sympltname[1024];
272 Elf *elf;
273 int nr = 0, symidx, err = 0;
274
275 if (!ss->dynsym)
276 return 0;
277
278 elf = ss->elf;
279 ehdr = ss->ehdr;
280
281 scn_dynsym = ss->dynsym;
282 shdr_dynsym = ss->dynshdr;
283 dynsym_idx = ss->dynsym_idx;
284
285 if (scn_dynsym == NULL)
286 goto out_elf_end;
287
288 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
289 ".rela.plt", NULL);
290 if (scn_plt_rel == NULL) {
291 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
292 ".rel.plt", NULL);
293 if (scn_plt_rel == NULL)
294 goto out_elf_end;
295 }
296
297 err = -1;
298
299 if (shdr_rel_plt.sh_link != dynsym_idx)
300 goto out_elf_end;
301
302 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
303 goto out_elf_end;
304
305 /*
306 * Fetch the relocation section to find the idxes to the GOT
307 * and the symbols in the .dynsym they refer to.
308 */
309 reldata = elf_getdata(scn_plt_rel, NULL);
310 if (reldata == NULL)
311 goto out_elf_end;
312
313 syms = elf_getdata(scn_dynsym, NULL);
314 if (syms == NULL)
315 goto out_elf_end;
316
317 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
318 if (scn_symstrs == NULL)
319 goto out_elf_end;
320
321 symstrs = elf_getdata(scn_symstrs, NULL);
322 if (symstrs == NULL)
323 goto out_elf_end;
324
325 if (symstrs->d_size == 0)
326 goto out_elf_end;
327
328 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
329 plt_offset = shdr_plt.sh_offset;
330 switch (ehdr.e_machine) {
331 case EM_ARM:
332 plt_header_size = 20;
333 plt_entry_size = 12;
334 break;
335
336 case EM_AARCH64:
337 plt_header_size = 32;
338 plt_entry_size = 16;
339 break;
340
341 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/sparc/xtensa need to be checked */
342 plt_header_size = shdr_plt.sh_entsize;
343 plt_entry_size = shdr_plt.sh_entsize;
344 break;
345 }
346 plt_offset += plt_header_size;
347
348 if (shdr_rel_plt.sh_type == SHT_RELA) {
349 GElf_Rela pos_mem, *pos;
350
351 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
352 nr_rel_entries) {
353 const char *elf_name = NULL;
354 char *demangled = NULL;
355 symidx = GELF_R_SYM(pos->r_info);
356 gelf_getsym(syms, symidx, &sym);
357
358 elf_name = elf_sym__name(&sym, symstrs);
359 demangled = demangle_sym(dso, 0, elf_name);
360 if (demangled != NULL)
361 elf_name = demangled;
362 snprintf(sympltname, sizeof(sympltname),
363 "%s@plt", elf_name);
364 free(demangled);
365
366 f = symbol__new(plt_offset, plt_entry_size,
367 STB_GLOBAL, sympltname);
368 if (!f)
369 goto out_elf_end;
370
371 plt_offset += plt_entry_size;
372 symbols__insert(&dso->symbols[map->type], f);
373 ++nr;
374 }
375 } else if (shdr_rel_plt.sh_type == SHT_REL) {
376 GElf_Rel pos_mem, *pos;
377 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
378 nr_rel_entries) {
379 const char *elf_name = NULL;
380 char *demangled = NULL;
381 symidx = GELF_R_SYM(pos->r_info);
382 gelf_getsym(syms, symidx, &sym);
383
384 elf_name = elf_sym__name(&sym, symstrs);
385 demangled = demangle_sym(dso, 0, elf_name);
386 if (demangled != NULL)
387 elf_name = demangled;
388 snprintf(sympltname, sizeof(sympltname),
389 "%s@plt", elf_name);
390 free(demangled);
391
392 f = symbol__new(plt_offset, plt_entry_size,
393 STB_GLOBAL, sympltname);
394 if (!f)
395 goto out_elf_end;
396
397 plt_offset += plt_entry_size;
398 symbols__insert(&dso->symbols[map->type], f);
399 ++nr;
400 }
401 }
402
403 err = 0;
404 out_elf_end:
405 if (err == 0)
406 return nr;
407 pr_debug("%s: problems reading %s PLT info.\n",
408 __func__, dso->long_name);
409 return 0;
410 }
411
412 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
413 {
414 return demangle_sym(dso, kmodule, elf_name);
415 }
416
417 /*
418 * Align offset to 4 bytes as needed for note name and descriptor data.
419 */
420 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
421
422 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
423 {
424 int err = -1;
425 GElf_Ehdr ehdr;
426 GElf_Shdr shdr;
427 Elf_Data *data;
428 Elf_Scn *sec;
429 Elf_Kind ek;
430 void *ptr;
431
432 if (size < BUILD_ID_SIZE)
433 goto out;
434
435 ek = elf_kind(elf);
436 if (ek != ELF_K_ELF)
437 goto out;
438
439 if (gelf_getehdr(elf, &ehdr) == NULL) {
440 pr_err("%s: cannot get elf header.\n", __func__);
441 goto out;
442 }
443
444 /*
445 * Check following sections for notes:
446 * '.note.gnu.build-id'
447 * '.notes'
448 * '.note' (VDSO specific)
449 */
450 do {
451 sec = elf_section_by_name(elf, &ehdr, &shdr,
452 ".note.gnu.build-id", NULL);
453 if (sec)
454 break;
455
456 sec = elf_section_by_name(elf, &ehdr, &shdr,
457 ".notes", NULL);
458 if (sec)
459 break;
460
461 sec = elf_section_by_name(elf, &ehdr, &shdr,
462 ".note", NULL);
463 if (sec)
464 break;
465
466 return err;
467
468 } while (0);
469
470 data = elf_getdata(sec, NULL);
471 if (data == NULL)
472 goto out;
473
474 ptr = data->d_buf;
475 while (ptr < (data->d_buf + data->d_size)) {
476 GElf_Nhdr *nhdr = ptr;
477 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
478 descsz = NOTE_ALIGN(nhdr->n_descsz);
479 const char *name;
480
481 ptr += sizeof(*nhdr);
482 name = ptr;
483 ptr += namesz;
484 if (nhdr->n_type == NT_GNU_BUILD_ID &&
485 nhdr->n_namesz == sizeof("GNU")) {
486 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
487 size_t sz = min(size, descsz);
488 memcpy(bf, ptr, sz);
489 memset(bf + sz, 0, size - sz);
490 err = descsz;
491 break;
492 }
493 }
494 ptr += descsz;
495 }
496
497 out:
498 return err;
499 }
500
501 int filename__read_build_id(const char *filename, void *bf, size_t size)
502 {
503 int fd, err = -1;
504 Elf *elf;
505
506 if (size < BUILD_ID_SIZE)
507 goto out;
508
509 fd = open(filename, O_RDONLY);
510 if (fd < 0)
511 goto out;
512
513 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
514 if (elf == NULL) {
515 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
516 goto out_close;
517 }
518
519 err = elf_read_build_id(elf, bf, size);
520
521 elf_end(elf);
522 out_close:
523 close(fd);
524 out:
525 return err;
526 }
527
528 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
529 {
530 int fd, err = -1;
531
532 if (size < BUILD_ID_SIZE)
533 goto out;
534
535 fd = open(filename, O_RDONLY);
536 if (fd < 0)
537 goto out;
538
539 while (1) {
540 char bf[BUFSIZ];
541 GElf_Nhdr nhdr;
542 size_t namesz, descsz;
543
544 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
545 break;
546
547 namesz = NOTE_ALIGN(nhdr.n_namesz);
548 descsz = NOTE_ALIGN(nhdr.n_descsz);
549 if (nhdr.n_type == NT_GNU_BUILD_ID &&
550 nhdr.n_namesz == sizeof("GNU")) {
551 if (read(fd, bf, namesz) != (ssize_t)namesz)
552 break;
553 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
554 size_t sz = min(descsz, size);
555 if (read(fd, build_id, sz) == (ssize_t)sz) {
556 memset(build_id + sz, 0, size - sz);
557 err = 0;
558 break;
559 }
560 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
561 break;
562 } else {
563 int n = namesz + descsz;
564
565 if (n > (int)sizeof(bf)) {
566 n = sizeof(bf);
567 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
568 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
569 }
570 if (read(fd, bf, n) != n)
571 break;
572 }
573 }
574 close(fd);
575 out:
576 return err;
577 }
578
579 int filename__read_debuglink(const char *filename, char *debuglink,
580 size_t size)
581 {
582 int fd, err = -1;
583 Elf *elf;
584 GElf_Ehdr ehdr;
585 GElf_Shdr shdr;
586 Elf_Data *data;
587 Elf_Scn *sec;
588 Elf_Kind ek;
589
590 fd = open(filename, O_RDONLY);
591 if (fd < 0)
592 goto out;
593
594 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
595 if (elf == NULL) {
596 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
597 goto out_close;
598 }
599
600 ek = elf_kind(elf);
601 if (ek != ELF_K_ELF)
602 goto out_elf_end;
603
604 if (gelf_getehdr(elf, &ehdr) == NULL) {
605 pr_err("%s: cannot get elf header.\n", __func__);
606 goto out_elf_end;
607 }
608
609 sec = elf_section_by_name(elf, &ehdr, &shdr,
610 ".gnu_debuglink", NULL);
611 if (sec == NULL)
612 goto out_elf_end;
613
614 data = elf_getdata(sec, NULL);
615 if (data == NULL)
616 goto out_elf_end;
617
618 /* the start of this section is a zero-terminated string */
619 strncpy(debuglink, data->d_buf, size);
620
621 err = 0;
622
623 out_elf_end:
624 elf_end(elf);
625 out_close:
626 close(fd);
627 out:
628 return err;
629 }
630
631 static int dso__swap_init(struct dso *dso, unsigned char eidata)
632 {
633 static unsigned int const endian = 1;
634
635 dso->needs_swap = DSO_SWAP__NO;
636
637 switch (eidata) {
638 case ELFDATA2LSB:
639 /* We are big endian, DSO is little endian. */
640 if (*(unsigned char const *)&endian != 1)
641 dso->needs_swap = DSO_SWAP__YES;
642 break;
643
644 case ELFDATA2MSB:
645 /* We are little endian, DSO is big endian. */
646 if (*(unsigned char const *)&endian != 0)
647 dso->needs_swap = DSO_SWAP__YES;
648 break;
649
650 default:
651 pr_err("unrecognized DSO data encoding %d\n", eidata);
652 return -EINVAL;
653 }
654
655 return 0;
656 }
657
658 bool symsrc__possibly_runtime(struct symsrc *ss)
659 {
660 return ss->dynsym || ss->opdsec;
661 }
662
663 bool symsrc__has_symtab(struct symsrc *ss)
664 {
665 return ss->symtab != NULL;
666 }
667
668 void symsrc__destroy(struct symsrc *ss)
669 {
670 zfree(&ss->name);
671 elf_end(ss->elf);
672 close(ss->fd);
673 }
674
675 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
676 {
677 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
678 }
679
680 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
681 enum dso_binary_type type)
682 {
683 int err = -1;
684 GElf_Ehdr ehdr;
685 Elf *elf;
686 int fd;
687
688 if (dso__needs_decompress(dso)) {
689 fd = dso__decompress_kmodule_fd(dso, name);
690 if (fd < 0)
691 return -1;
692
693 type = dso->symtab_type;
694 } else {
695 fd = open(name, O_RDONLY);
696 if (fd < 0) {
697 dso->load_errno = errno;
698 return -1;
699 }
700 }
701
702 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
703 if (elf == NULL) {
704 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
705 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
706 goto out_close;
707 }
708
709 if (gelf_getehdr(elf, &ehdr) == NULL) {
710 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
711 pr_debug("%s: cannot get elf header.\n", __func__);
712 goto out_elf_end;
713 }
714
715 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
716 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
717 goto out_elf_end;
718 }
719
720 /* Always reject images with a mismatched build-id: */
721 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
722 u8 build_id[BUILD_ID_SIZE];
723
724 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
725 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
726 goto out_elf_end;
727 }
728
729 if (!dso__build_id_equal(dso, build_id)) {
730 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
731 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
732 goto out_elf_end;
733 }
734 }
735
736 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
737
738 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
739 NULL);
740 if (ss->symshdr.sh_type != SHT_SYMTAB)
741 ss->symtab = NULL;
742
743 ss->dynsym_idx = 0;
744 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
745 &ss->dynsym_idx);
746 if (ss->dynshdr.sh_type != SHT_DYNSYM)
747 ss->dynsym = NULL;
748
749 ss->opdidx = 0;
750 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
751 &ss->opdidx);
752 if (ss->opdshdr.sh_type != SHT_PROGBITS)
753 ss->opdsec = NULL;
754
755 if (dso->kernel == DSO_TYPE_USER)
756 ss->adjust_symbols = true;
757 else
758 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
759
760 ss->name = strdup(name);
761 if (!ss->name) {
762 dso->load_errno = errno;
763 goto out_elf_end;
764 }
765
766 ss->elf = elf;
767 ss->fd = fd;
768 ss->ehdr = ehdr;
769 ss->type = type;
770
771 return 0;
772
773 out_elf_end:
774 elf_end(elf);
775 out_close:
776 close(fd);
777 return err;
778 }
779
780 /**
781 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
782 * @kmap: kernel maps and relocation reference symbol
783 *
784 * This function returns %true if we are dealing with the kernel maps and the
785 * relocation reference symbol has not yet been found. Otherwise %false is
786 * returned.
787 */
788 static bool ref_reloc_sym_not_found(struct kmap *kmap)
789 {
790 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
791 !kmap->ref_reloc_sym->unrelocated_addr;
792 }
793
794 /**
795 * ref_reloc - kernel relocation offset.
796 * @kmap: kernel maps and relocation reference symbol
797 *
798 * This function returns the offset of kernel addresses as determined by using
799 * the relocation reference symbol i.e. if the kernel has not been relocated
800 * then the return value is zero.
801 */
802 static u64 ref_reloc(struct kmap *kmap)
803 {
804 if (kmap && kmap->ref_reloc_sym &&
805 kmap->ref_reloc_sym->unrelocated_addr)
806 return kmap->ref_reloc_sym->addr -
807 kmap->ref_reloc_sym->unrelocated_addr;
808 return 0;
809 }
810
811 void __weak arch__sym_update(struct symbol *s __maybe_unused,
812 GElf_Sym *sym __maybe_unused) { }
813
814 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
815 struct symsrc *runtime_ss, int kmodule)
816 {
817 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
818 struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
819 struct map *curr_map = map;
820 struct dso *curr_dso = dso;
821 Elf_Data *symstrs, *secstrs;
822 uint32_t nr_syms;
823 int err = -1;
824 uint32_t idx;
825 GElf_Ehdr ehdr;
826 GElf_Shdr shdr;
827 GElf_Shdr tshdr;
828 Elf_Data *syms, *opddata = NULL;
829 GElf_Sym sym;
830 Elf_Scn *sec, *sec_strndx;
831 Elf *elf;
832 int nr = 0;
833 bool remap_kernel = false, adjust_kernel_syms = false;
834
835 if (kmap && !kmaps)
836 return -1;
837
838 dso->symtab_type = syms_ss->type;
839 dso->is_64_bit = syms_ss->is_64_bit;
840 dso->rel = syms_ss->ehdr.e_type == ET_REL;
841
842 /*
843 * Modules may already have symbols from kallsyms, but those symbols
844 * have the wrong values for the dso maps, so remove them.
845 */
846 if (kmodule && syms_ss->symtab)
847 symbols__delete(&dso->symbols[map->type]);
848
849 if (!syms_ss->symtab) {
850 /*
851 * If the vmlinux is stripped, fail so we will fall back
852 * to using kallsyms. The vmlinux runtime symbols aren't
853 * of much use.
854 */
855 if (dso->kernel)
856 goto out_elf_end;
857
858 syms_ss->symtab = syms_ss->dynsym;
859 syms_ss->symshdr = syms_ss->dynshdr;
860 }
861
862 elf = syms_ss->elf;
863 ehdr = syms_ss->ehdr;
864 sec = syms_ss->symtab;
865 shdr = syms_ss->symshdr;
866
867 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
868 ".text", NULL))
869 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
870
871 if (runtime_ss->opdsec)
872 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
873
874 syms = elf_getdata(sec, NULL);
875 if (syms == NULL)
876 goto out_elf_end;
877
878 sec = elf_getscn(elf, shdr.sh_link);
879 if (sec == NULL)
880 goto out_elf_end;
881
882 symstrs = elf_getdata(sec, NULL);
883 if (symstrs == NULL)
884 goto out_elf_end;
885
886 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
887 if (sec_strndx == NULL)
888 goto out_elf_end;
889
890 secstrs = elf_getdata(sec_strndx, NULL);
891 if (secstrs == NULL)
892 goto out_elf_end;
893
894 nr_syms = shdr.sh_size / shdr.sh_entsize;
895
896 memset(&sym, 0, sizeof(sym));
897
898 /*
899 * The kernel relocation symbol is needed in advance in order to adjust
900 * kernel maps correctly.
901 */
902 if (ref_reloc_sym_not_found(kmap)) {
903 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
904 const char *elf_name = elf_sym__name(&sym, symstrs);
905
906 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
907 continue;
908 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
909 map->reloc = kmap->ref_reloc_sym->addr -
910 kmap->ref_reloc_sym->unrelocated_addr;
911 break;
912 }
913 }
914
915 /*
916 * Handle any relocation of vdso necessary because older kernels
917 * attempted to prelink vdso to its virtual address.
918 */
919 if (dso__is_vdso(dso))
920 map->reloc = map->start - dso->text_offset;
921
922 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
923 /*
924 * Initial kernel and module mappings do not map to the dso. For
925 * function mappings, flag the fixups.
926 */
927 if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
928 remap_kernel = true;
929 adjust_kernel_syms = dso->adjust_symbols;
930 }
931 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
932 struct symbol *f;
933 const char *elf_name = elf_sym__name(&sym, symstrs);
934 char *demangled = NULL;
935 int is_label = elf_sym__is_label(&sym);
936 const char *section_name;
937 bool used_opd = false;
938
939 if (!is_label && !elf_sym__is_a(&sym, map->type))
940 continue;
941
942 /* Reject ARM ELF "mapping symbols": these aren't unique and
943 * don't identify functions, so will confuse the profile
944 * output: */
945 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
946 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
947 && (elf_name[2] == '\0' || elf_name[2] == '.'))
948 continue;
949 }
950
951 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
952 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
953 u64 *opd = opddata->d_buf + offset;
954 sym.st_value = DSO__SWAP(dso, u64, *opd);
955 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
956 sym.st_value);
957 used_opd = true;
958 }
959 /*
960 * When loading symbols in a data mapping, ABS symbols (which
961 * has a value of SHN_ABS in its st_shndx) failed at
962 * elf_getscn(). And it marks the loading as a failure so
963 * already loaded symbols cannot be fixed up.
964 *
965 * I'm not sure what should be done. Just ignore them for now.
966 * - Namhyung Kim
967 */
968 if (sym.st_shndx == SHN_ABS)
969 continue;
970
971 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
972 if (!sec)
973 goto out_elf_end;
974
975 gelf_getshdr(sec, &shdr);
976
977 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
978 continue;
979
980 section_name = elf_sec__name(&shdr, secstrs);
981
982 /* On ARM, symbols for thumb functions have 1 added to
983 * the symbol address as a flag - remove it */
984 if ((ehdr.e_machine == EM_ARM) &&
985 (map->type == MAP__FUNCTION) &&
986 (sym.st_value & 1))
987 --sym.st_value;
988
989 if (dso->kernel || kmodule) {
990 char dso_name[PATH_MAX];
991
992 /* Adjust symbol to map to file offset */
993 if (adjust_kernel_syms)
994 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
995
996 if (strcmp(section_name,
997 (curr_dso->short_name +
998 dso->short_name_len)) == 0)
999 goto new_symbol;
1000
1001 if (strcmp(section_name, ".text") == 0) {
1002 /*
1003 * The initial kernel mapping is based on
1004 * kallsyms and identity maps. Overwrite it to
1005 * map to the kernel dso.
1006 */
1007 if (remap_kernel && dso->kernel) {
1008 remap_kernel = false;
1009 map->start = shdr.sh_addr +
1010 ref_reloc(kmap);
1011 map->end = map->start + shdr.sh_size;
1012 map->pgoff = shdr.sh_offset;
1013 map->map_ip = map__map_ip;
1014 map->unmap_ip = map__unmap_ip;
1015 /* Ensure maps are correctly ordered */
1016 if (kmaps) {
1017 map__get(map);
1018 map_groups__remove(kmaps, map);
1019 map_groups__insert(kmaps, map);
1020 map__put(map);
1021 }
1022 }
1023
1024 /*
1025 * The initial module mapping is based on
1026 * /proc/modules mapped to offset zero.
1027 * Overwrite it to map to the module dso.
1028 */
1029 if (remap_kernel && kmodule) {
1030 remap_kernel = false;
1031 map->pgoff = shdr.sh_offset;
1032 }
1033
1034 curr_map = map;
1035 curr_dso = dso;
1036 goto new_symbol;
1037 }
1038
1039 if (!kmap)
1040 goto new_symbol;
1041
1042 snprintf(dso_name, sizeof(dso_name),
1043 "%s%s", dso->short_name, section_name);
1044
1045 curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1046 if (curr_map == NULL) {
1047 u64 start = sym.st_value;
1048
1049 if (kmodule)
1050 start += map->start + shdr.sh_offset;
1051
1052 curr_dso = dso__new(dso_name);
1053 if (curr_dso == NULL)
1054 goto out_elf_end;
1055 curr_dso->kernel = dso->kernel;
1056 curr_dso->long_name = dso->long_name;
1057 curr_dso->long_name_len = dso->long_name_len;
1058 curr_map = map__new2(start, curr_dso,
1059 map->type);
1060 dso__put(curr_dso);
1061 if (curr_map == NULL) {
1062 goto out_elf_end;
1063 }
1064 if (adjust_kernel_syms) {
1065 curr_map->start = shdr.sh_addr +
1066 ref_reloc(kmap);
1067 curr_map->end = curr_map->start +
1068 shdr.sh_size;
1069 curr_map->pgoff = shdr.sh_offset;
1070 } else {
1071 curr_map->map_ip = identity__map_ip;
1072 curr_map->unmap_ip = identity__map_ip;
1073 }
1074 curr_dso->symtab_type = dso->symtab_type;
1075 map_groups__insert(kmaps, curr_map);
1076 /*
1077 * Add it before we drop the referece to curr_map,
1078 * i.e. while we still are sure to have a reference
1079 * to this DSO via curr_map->dso.
1080 */
1081 dsos__add(&map->groups->machine->dsos, curr_dso);
1082 /* kmaps already got it */
1083 map__put(curr_map);
1084 dso__set_loaded(curr_dso, map->type);
1085 } else
1086 curr_dso = curr_map->dso;
1087
1088 goto new_symbol;
1089 }
1090
1091 if ((used_opd && runtime_ss->adjust_symbols)
1092 || (!used_opd && syms_ss->adjust_symbols)) {
1093 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1094 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1095 (u64)sym.st_value, (u64)shdr.sh_addr,
1096 (u64)shdr.sh_offset);
1097 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1098 }
1099 new_symbol:
1100 demangled = demangle_sym(dso, kmodule, elf_name);
1101 if (demangled != NULL)
1102 elf_name = demangled;
1103
1104 f = symbol__new(sym.st_value, sym.st_size,
1105 GELF_ST_BIND(sym.st_info), elf_name);
1106 free(demangled);
1107 if (!f)
1108 goto out_elf_end;
1109
1110 arch__sym_update(f, &sym);
1111
1112 __symbols__insert(&curr_dso->symbols[curr_map->type], f, dso->kernel);
1113 nr++;
1114 }
1115
1116 /*
1117 * For misannotated, zeroed, ASM function sizes.
1118 */
1119 if (nr > 0) {
1120 symbols__fixup_end(&dso->symbols[map->type]);
1121 symbols__fixup_duplicate(&dso->symbols[map->type]);
1122 if (kmap) {
1123 /*
1124 * We need to fixup this here too because we create new
1125 * maps here, for things like vsyscall sections.
1126 */
1127 __map_groups__fixup_end(kmaps, map->type);
1128 }
1129 }
1130 err = nr;
1131 out_elf_end:
1132 return err;
1133 }
1134
1135 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1136 {
1137 GElf_Phdr phdr;
1138 size_t i, phdrnum;
1139 int err;
1140 u64 sz;
1141
1142 if (elf_getphdrnum(elf, &phdrnum))
1143 return -1;
1144
1145 for (i = 0; i < phdrnum; i++) {
1146 if (gelf_getphdr(elf, i, &phdr) == NULL)
1147 return -1;
1148 if (phdr.p_type != PT_LOAD)
1149 continue;
1150 if (exe) {
1151 if (!(phdr.p_flags & PF_X))
1152 continue;
1153 } else {
1154 if (!(phdr.p_flags & PF_R))
1155 continue;
1156 }
1157 sz = min(phdr.p_memsz, phdr.p_filesz);
1158 if (!sz)
1159 continue;
1160 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1161 if (err)
1162 return err;
1163 }
1164 return 0;
1165 }
1166
1167 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1168 bool *is_64_bit)
1169 {
1170 int err;
1171 Elf *elf;
1172
1173 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1174 if (elf == NULL)
1175 return -1;
1176
1177 if (is_64_bit)
1178 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1179
1180 err = elf_read_maps(elf, exe, mapfn, data);
1181
1182 elf_end(elf);
1183 return err;
1184 }
1185
1186 enum dso_type dso__type_fd(int fd)
1187 {
1188 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1189 GElf_Ehdr ehdr;
1190 Elf_Kind ek;
1191 Elf *elf;
1192
1193 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1194 if (elf == NULL)
1195 goto out;
1196
1197 ek = elf_kind(elf);
1198 if (ek != ELF_K_ELF)
1199 goto out_end;
1200
1201 if (gelf_getclass(elf) == ELFCLASS64) {
1202 dso_type = DSO__TYPE_64BIT;
1203 goto out_end;
1204 }
1205
1206 if (gelf_getehdr(elf, &ehdr) == NULL)
1207 goto out_end;
1208
1209 if (ehdr.e_machine == EM_X86_64)
1210 dso_type = DSO__TYPE_X32BIT;
1211 else
1212 dso_type = DSO__TYPE_32BIT;
1213 out_end:
1214 elf_end(elf);
1215 out:
1216 return dso_type;
1217 }
1218
1219 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1220 {
1221 ssize_t r;
1222 size_t n;
1223 int err = -1;
1224 char *buf = malloc(page_size);
1225
1226 if (buf == NULL)
1227 return -1;
1228
1229 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1230 goto out;
1231
1232 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1233 goto out;
1234
1235 while (len) {
1236 n = page_size;
1237 if (len < n)
1238 n = len;
1239 /* Use read because mmap won't work on proc files */
1240 r = read(from, buf, n);
1241 if (r < 0)
1242 goto out;
1243 if (!r)
1244 break;
1245 n = r;
1246 r = write(to, buf, n);
1247 if (r < 0)
1248 goto out;
1249 if ((size_t)r != n)
1250 goto out;
1251 len -= n;
1252 }
1253
1254 err = 0;
1255 out:
1256 free(buf);
1257 return err;
1258 }
1259
1260 struct kcore {
1261 int fd;
1262 int elfclass;
1263 Elf *elf;
1264 GElf_Ehdr ehdr;
1265 };
1266
1267 static int kcore__open(struct kcore *kcore, const char *filename)
1268 {
1269 GElf_Ehdr *ehdr;
1270
1271 kcore->fd = open(filename, O_RDONLY);
1272 if (kcore->fd == -1)
1273 return -1;
1274
1275 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1276 if (!kcore->elf)
1277 goto out_close;
1278
1279 kcore->elfclass = gelf_getclass(kcore->elf);
1280 if (kcore->elfclass == ELFCLASSNONE)
1281 goto out_end;
1282
1283 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1284 if (!ehdr)
1285 goto out_end;
1286
1287 return 0;
1288
1289 out_end:
1290 elf_end(kcore->elf);
1291 out_close:
1292 close(kcore->fd);
1293 return -1;
1294 }
1295
1296 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1297 bool temp)
1298 {
1299 kcore->elfclass = elfclass;
1300
1301 if (temp)
1302 kcore->fd = mkstemp(filename);
1303 else
1304 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1305 if (kcore->fd == -1)
1306 return -1;
1307
1308 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1309 if (!kcore->elf)
1310 goto out_close;
1311
1312 if (!gelf_newehdr(kcore->elf, elfclass))
1313 goto out_end;
1314
1315 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1316
1317 return 0;
1318
1319 out_end:
1320 elf_end(kcore->elf);
1321 out_close:
1322 close(kcore->fd);
1323 unlink(filename);
1324 return -1;
1325 }
1326
1327 static void kcore__close(struct kcore *kcore)
1328 {
1329 elf_end(kcore->elf);
1330 close(kcore->fd);
1331 }
1332
1333 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1334 {
1335 GElf_Ehdr *ehdr = &to->ehdr;
1336 GElf_Ehdr *kehdr = &from->ehdr;
1337
1338 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1339 ehdr->e_type = kehdr->e_type;
1340 ehdr->e_machine = kehdr->e_machine;
1341 ehdr->e_version = kehdr->e_version;
1342 ehdr->e_entry = 0;
1343 ehdr->e_shoff = 0;
1344 ehdr->e_flags = kehdr->e_flags;
1345 ehdr->e_phnum = count;
1346 ehdr->e_shentsize = 0;
1347 ehdr->e_shnum = 0;
1348 ehdr->e_shstrndx = 0;
1349
1350 if (from->elfclass == ELFCLASS32) {
1351 ehdr->e_phoff = sizeof(Elf32_Ehdr);
1352 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
1353 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1354 } else {
1355 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1356 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1357 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1358 }
1359
1360 if (!gelf_update_ehdr(to->elf, ehdr))
1361 return -1;
1362
1363 if (!gelf_newphdr(to->elf, count))
1364 return -1;
1365
1366 return 0;
1367 }
1368
1369 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1370 u64 addr, u64 len)
1371 {
1372 GElf_Phdr phdr = {
1373 .p_type = PT_LOAD,
1374 .p_flags = PF_R | PF_W | PF_X,
1375 .p_offset = offset,
1376 .p_vaddr = addr,
1377 .p_paddr = 0,
1378 .p_filesz = len,
1379 .p_memsz = len,
1380 .p_align = page_size,
1381 };
1382
1383 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1384 return -1;
1385
1386 return 0;
1387 }
1388
1389 static off_t kcore__write(struct kcore *kcore)
1390 {
1391 return elf_update(kcore->elf, ELF_C_WRITE);
1392 }
1393
1394 struct phdr_data {
1395 off_t offset;
1396 u64 addr;
1397 u64 len;
1398 };
1399
1400 struct kcore_copy_info {
1401 u64 stext;
1402 u64 etext;
1403 u64 first_symbol;
1404 u64 last_symbol;
1405 u64 first_module;
1406 u64 last_module_symbol;
1407 struct phdr_data kernel_map;
1408 struct phdr_data modules_map;
1409 };
1410
1411 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1412 u64 start)
1413 {
1414 struct kcore_copy_info *kci = arg;
1415
1416 if (!symbol_type__is_a(type, MAP__FUNCTION))
1417 return 0;
1418
1419 if (strchr(name, '[')) {
1420 if (start > kci->last_module_symbol)
1421 kci->last_module_symbol = start;
1422 return 0;
1423 }
1424
1425 if (!kci->first_symbol || start < kci->first_symbol)
1426 kci->first_symbol = start;
1427
1428 if (!kci->last_symbol || start > kci->last_symbol)
1429 kci->last_symbol = start;
1430
1431 if (!strcmp(name, "_stext")) {
1432 kci->stext = start;
1433 return 0;
1434 }
1435
1436 if (!strcmp(name, "_etext")) {
1437 kci->etext = start;
1438 return 0;
1439 }
1440
1441 return 0;
1442 }
1443
1444 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1445 const char *dir)
1446 {
1447 char kallsyms_filename[PATH_MAX];
1448
1449 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1450
1451 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1452 return -1;
1453
1454 if (kallsyms__parse(kallsyms_filename, kci,
1455 kcore_copy__process_kallsyms) < 0)
1456 return -1;
1457
1458 return 0;
1459 }
1460
1461 static int kcore_copy__process_modules(void *arg,
1462 const char *name __maybe_unused,
1463 u64 start, u64 size __maybe_unused)
1464 {
1465 struct kcore_copy_info *kci = arg;
1466
1467 if (!kci->first_module || start < kci->first_module)
1468 kci->first_module = start;
1469
1470 return 0;
1471 }
1472
1473 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1474 const char *dir)
1475 {
1476 char modules_filename[PATH_MAX];
1477
1478 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1479
1480 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1481 return -1;
1482
1483 if (modules__parse(modules_filename, kci,
1484 kcore_copy__process_modules) < 0)
1485 return -1;
1486
1487 return 0;
1488 }
1489
1490 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1491 u64 s, u64 e)
1492 {
1493 if (p->addr || s < start || s >= end)
1494 return;
1495
1496 p->addr = s;
1497 p->offset = (s - start) + pgoff;
1498 p->len = e < end ? e - s : end - s;
1499 }
1500
1501 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1502 {
1503 struct kcore_copy_info *kci = data;
1504 u64 end = start + len;
1505
1506 kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1507 kci->etext);
1508
1509 kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1510 kci->last_module_symbol);
1511
1512 return 0;
1513 }
1514
1515 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1516 {
1517 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1518 return -1;
1519
1520 return 0;
1521 }
1522
1523 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1524 Elf *elf)
1525 {
1526 if (kcore_copy__parse_kallsyms(kci, dir))
1527 return -1;
1528
1529 if (kcore_copy__parse_modules(kci, dir))
1530 return -1;
1531
1532 if (kci->stext)
1533 kci->stext = round_down(kci->stext, page_size);
1534 else
1535 kci->stext = round_down(kci->first_symbol, page_size);
1536
1537 if (kci->etext) {
1538 kci->etext = round_up(kci->etext, page_size);
1539 } else if (kci->last_symbol) {
1540 kci->etext = round_up(kci->last_symbol, page_size);
1541 kci->etext += page_size;
1542 }
1543
1544 kci->first_module = round_down(kci->first_module, page_size);
1545
1546 if (kci->last_module_symbol) {
1547 kci->last_module_symbol = round_up(kci->last_module_symbol,
1548 page_size);
1549 kci->last_module_symbol += page_size;
1550 }
1551
1552 if (!kci->stext || !kci->etext)
1553 return -1;
1554
1555 if (kci->first_module && !kci->last_module_symbol)
1556 return -1;
1557
1558 return kcore_copy__read_maps(kci, elf);
1559 }
1560
1561 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1562 const char *name)
1563 {
1564 char from_filename[PATH_MAX];
1565 char to_filename[PATH_MAX];
1566
1567 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1568 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1569
1570 return copyfile_mode(from_filename, to_filename, 0400);
1571 }
1572
1573 static int kcore_copy__unlink(const char *dir, const char *name)
1574 {
1575 char filename[PATH_MAX];
1576
1577 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1578
1579 return unlink(filename);
1580 }
1581
1582 static int kcore_copy__compare_fds(int from, int to)
1583 {
1584 char *buf_from;
1585 char *buf_to;
1586 ssize_t ret;
1587 size_t len;
1588 int err = -1;
1589
1590 buf_from = malloc(page_size);
1591 buf_to = malloc(page_size);
1592 if (!buf_from || !buf_to)
1593 goto out;
1594
1595 while (1) {
1596 /* Use read because mmap won't work on proc files */
1597 ret = read(from, buf_from, page_size);
1598 if (ret < 0)
1599 goto out;
1600
1601 if (!ret)
1602 break;
1603
1604 len = ret;
1605
1606 if (readn(to, buf_to, len) != (int)len)
1607 goto out;
1608
1609 if (memcmp(buf_from, buf_to, len))
1610 goto out;
1611 }
1612
1613 err = 0;
1614 out:
1615 free(buf_to);
1616 free(buf_from);
1617 return err;
1618 }
1619
1620 static int kcore_copy__compare_files(const char *from_filename,
1621 const char *to_filename)
1622 {
1623 int from, to, err = -1;
1624
1625 from = open(from_filename, O_RDONLY);
1626 if (from < 0)
1627 return -1;
1628
1629 to = open(to_filename, O_RDONLY);
1630 if (to < 0)
1631 goto out_close_from;
1632
1633 err = kcore_copy__compare_fds(from, to);
1634
1635 close(to);
1636 out_close_from:
1637 close(from);
1638 return err;
1639 }
1640
1641 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1642 const char *name)
1643 {
1644 char from_filename[PATH_MAX];
1645 char to_filename[PATH_MAX];
1646
1647 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1648 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1649
1650 return kcore_copy__compare_files(from_filename, to_filename);
1651 }
1652
1653 /**
1654 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1655 * @from_dir: from directory
1656 * @to_dir: to directory
1657 *
1658 * This function copies kallsyms, modules and kcore files from one directory to
1659 * another. kallsyms and modules are copied entirely. Only code segments are
1660 * copied from kcore. It is assumed that two segments suffice: one for the
1661 * kernel proper and one for all the modules. The code segments are determined
1662 * from kallsyms and modules files. The kernel map starts at _stext or the
1663 * lowest function symbol, and ends at _etext or the highest function symbol.
1664 * The module map starts at the lowest module address and ends at the highest
1665 * module symbol. Start addresses are rounded down to the nearest page. End
1666 * addresses are rounded up to the nearest page. An extra page is added to the
1667 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1668 * symbol too. Because it contains only code sections, the resulting kcore is
1669 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1670 * is not the same for the kernel map and the modules map. That happens because
1671 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1672 * kallsyms and modules files are compared with their copies to check that
1673 * modules have not been loaded or unloaded while the copies were taking place.
1674 *
1675 * Return: %0 on success, %-1 on failure.
1676 */
1677 int kcore_copy(const char *from_dir, const char *to_dir)
1678 {
1679 struct kcore kcore;
1680 struct kcore extract;
1681 size_t count = 2;
1682 int idx = 0, err = -1;
1683 off_t offset = page_size, sz, modules_offset = 0;
1684 struct kcore_copy_info kci = { .stext = 0, };
1685 char kcore_filename[PATH_MAX];
1686 char extract_filename[PATH_MAX];
1687
1688 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1689 return -1;
1690
1691 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1692 goto out_unlink_kallsyms;
1693
1694 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1695 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1696
1697 if (kcore__open(&kcore, kcore_filename))
1698 goto out_unlink_modules;
1699
1700 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1701 goto out_kcore_close;
1702
1703 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1704 goto out_kcore_close;
1705
1706 if (!kci.modules_map.addr)
1707 count -= 1;
1708
1709 if (kcore__copy_hdr(&kcore, &extract, count))
1710 goto out_extract_close;
1711
1712 if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1713 kci.kernel_map.len))
1714 goto out_extract_close;
1715
1716 if (kci.modules_map.addr) {
1717 modules_offset = offset + kci.kernel_map.len;
1718 if (kcore__add_phdr(&extract, idx, modules_offset,
1719 kci.modules_map.addr, kci.modules_map.len))
1720 goto out_extract_close;
1721 }
1722
1723 sz = kcore__write(&extract);
1724 if (sz < 0 || sz > offset)
1725 goto out_extract_close;
1726
1727 if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1728 kci.kernel_map.len))
1729 goto out_extract_close;
1730
1731 if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1732 extract.fd, modules_offset,
1733 kci.modules_map.len))
1734 goto out_extract_close;
1735
1736 if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1737 goto out_extract_close;
1738
1739 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1740 goto out_extract_close;
1741
1742 err = 0;
1743
1744 out_extract_close:
1745 kcore__close(&extract);
1746 if (err)
1747 unlink(extract_filename);
1748 out_kcore_close:
1749 kcore__close(&kcore);
1750 out_unlink_modules:
1751 if (err)
1752 kcore_copy__unlink(to_dir, "modules");
1753 out_unlink_kallsyms:
1754 if (err)
1755 kcore_copy__unlink(to_dir, "kallsyms");
1756
1757 return err;
1758 }
1759
1760 int kcore_extract__create(struct kcore_extract *kce)
1761 {
1762 struct kcore kcore;
1763 struct kcore extract;
1764 size_t count = 1;
1765 int idx = 0, err = -1;
1766 off_t offset = page_size, sz;
1767
1768 if (kcore__open(&kcore, kce->kcore_filename))
1769 return -1;
1770
1771 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1772 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1773 goto out_kcore_close;
1774
1775 if (kcore__copy_hdr(&kcore, &extract, count))
1776 goto out_extract_close;
1777
1778 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1779 goto out_extract_close;
1780
1781 sz = kcore__write(&extract);
1782 if (sz < 0 || sz > offset)
1783 goto out_extract_close;
1784
1785 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1786 goto out_extract_close;
1787
1788 err = 0;
1789
1790 out_extract_close:
1791 kcore__close(&extract);
1792 if (err)
1793 unlink(kce->extract_filename);
1794 out_kcore_close:
1795 kcore__close(&kcore);
1796
1797 return err;
1798 }
1799
1800 void kcore_extract__delete(struct kcore_extract *kce)
1801 {
1802 unlink(kce->extract_filename);
1803 }
1804
1805 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1806 /**
1807 * populate_sdt_note : Parse raw data and identify SDT note
1808 * @elf: elf of the opened file
1809 * @data: raw data of a section with description offset applied
1810 * @len: note description size
1811 * @type: type of the note
1812 * @sdt_notes: List to add the SDT note
1813 *
1814 * Responsible for parsing the @data in section .note.stapsdt in @elf and
1815 * if its an SDT note, it appends to @sdt_notes list.
1816 */
1817 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1818 struct list_head *sdt_notes)
1819 {
1820 const char *provider, *name, *args;
1821 struct sdt_note *tmp = NULL;
1822 GElf_Ehdr ehdr;
1823 GElf_Addr base_off = 0;
1824 GElf_Shdr shdr;
1825 int ret = -EINVAL;
1826
1827 union {
1828 Elf64_Addr a64[NR_ADDR];
1829 Elf32_Addr a32[NR_ADDR];
1830 } buf;
1831
1832 Elf_Data dst = {
1833 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1834 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1835 .d_off = 0, .d_align = 0
1836 };
1837 Elf_Data src = {
1838 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1839 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1840 .d_align = 0
1841 };
1842
1843 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1844 if (!tmp) {
1845 ret = -ENOMEM;
1846 goto out_err;
1847 }
1848
1849 INIT_LIST_HEAD(&tmp->note_list);
1850
1851 if (len < dst.d_size + 3)
1852 goto out_free_note;
1853
1854 /* Translation from file representation to memory representation */
1855 if (gelf_xlatetom(*elf, &dst, &src,
1856 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
1857 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
1858 goto out_free_note;
1859 }
1860
1861 /* Populate the fields of sdt_note */
1862 provider = data + dst.d_size;
1863
1864 name = (const char *)memchr(provider, '\0', data + len - provider);
1865 if (name++ == NULL)
1866 goto out_free_note;
1867
1868 tmp->provider = strdup(provider);
1869 if (!tmp->provider) {
1870 ret = -ENOMEM;
1871 goto out_free_note;
1872 }
1873 tmp->name = strdup(name);
1874 if (!tmp->name) {
1875 ret = -ENOMEM;
1876 goto out_free_prov;
1877 }
1878
1879 args = memchr(name, '\0', data + len - name);
1880
1881 /*
1882 * There is no argument if:
1883 * - We reached the end of the note;
1884 * - There is not enough room to hold a potential string;
1885 * - The argument string is empty or just contains ':'.
1886 */
1887 if (args == NULL || data + len - args < 2 ||
1888 args[1] == ':' || args[1] == '\0')
1889 tmp->args = NULL;
1890 else {
1891 tmp->args = strdup(++args);
1892 if (!tmp->args) {
1893 ret = -ENOMEM;
1894 goto out_free_name;
1895 }
1896 }
1897
1898 if (gelf_getclass(*elf) == ELFCLASS32) {
1899 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
1900 tmp->bit32 = true;
1901 } else {
1902 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
1903 tmp->bit32 = false;
1904 }
1905
1906 if (!gelf_getehdr(*elf, &ehdr)) {
1907 pr_debug("%s : cannot get elf header.\n", __func__);
1908 ret = -EBADF;
1909 goto out_free_args;
1910 }
1911
1912 /* Adjust the prelink effect :
1913 * Find out the .stapsdt.base section.
1914 * This scn will help us to handle prelinking (if present).
1915 * Compare the retrieved file offset of the base section with the
1916 * base address in the description of the SDT note. If its different,
1917 * then accordingly, adjust the note location.
1918 */
1919 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
1920 base_off = shdr.sh_offset;
1921 if (base_off) {
1922 if (tmp->bit32)
1923 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
1924 tmp->addr.a32[1];
1925 else
1926 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
1927 tmp->addr.a64[1];
1928 }
1929 }
1930
1931 list_add_tail(&tmp->note_list, sdt_notes);
1932 return 0;
1933
1934 out_free_args:
1935 free(tmp->args);
1936 out_free_name:
1937 free(tmp->name);
1938 out_free_prov:
1939 free(tmp->provider);
1940 out_free_note:
1941 free(tmp);
1942 out_err:
1943 return ret;
1944 }
1945
1946 /**
1947 * construct_sdt_notes_list : constructs a list of SDT notes
1948 * @elf : elf to look into
1949 * @sdt_notes : empty list_head
1950 *
1951 * Scans the sections in 'elf' for the section
1952 * .note.stapsdt. It, then calls populate_sdt_note to find
1953 * out the SDT events and populates the 'sdt_notes'.
1954 */
1955 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
1956 {
1957 GElf_Ehdr ehdr;
1958 Elf_Scn *scn = NULL;
1959 Elf_Data *data;
1960 GElf_Shdr shdr;
1961 size_t shstrndx, next;
1962 GElf_Nhdr nhdr;
1963 size_t name_off, desc_off, offset;
1964 int ret = 0;
1965
1966 if (gelf_getehdr(elf, &ehdr) == NULL) {
1967 ret = -EBADF;
1968 goto out_ret;
1969 }
1970 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
1971 ret = -EBADF;
1972 goto out_ret;
1973 }
1974
1975 /* Look for the required section */
1976 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
1977 if (!scn) {
1978 ret = -ENOENT;
1979 goto out_ret;
1980 }
1981
1982 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
1983 ret = -ENOENT;
1984 goto out_ret;
1985 }
1986
1987 data = elf_getdata(scn, NULL);
1988
1989 /* Get the SDT notes */
1990 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
1991 &desc_off)) > 0; offset = next) {
1992 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
1993 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
1994 sizeof(SDT_NOTE_NAME))) {
1995 /* Check the type of the note */
1996 if (nhdr.n_type != SDT_NOTE_TYPE)
1997 goto out_ret;
1998
1999 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2000 nhdr.n_descsz, sdt_notes);
2001 if (ret < 0)
2002 goto out_ret;
2003 }
2004 }
2005 if (list_empty(sdt_notes))
2006 ret = -ENOENT;
2007
2008 out_ret:
2009 return ret;
2010 }
2011
2012 /**
2013 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2014 * @head : empty list_head
2015 * @target : file to find SDT notes from
2016 *
2017 * This opens the file, initializes
2018 * the ELF and then calls construct_sdt_notes_list.
2019 */
2020 int get_sdt_note_list(struct list_head *head, const char *target)
2021 {
2022 Elf *elf;
2023 int fd, ret;
2024
2025 fd = open(target, O_RDONLY);
2026 if (fd < 0)
2027 return -EBADF;
2028
2029 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2030 if (!elf) {
2031 ret = -EBADF;
2032 goto out_close;
2033 }
2034 ret = construct_sdt_notes_list(elf, head);
2035 elf_end(elf);
2036 out_close:
2037 close(fd);
2038 return ret;
2039 }
2040
2041 /**
2042 * cleanup_sdt_note_list : free the sdt notes' list
2043 * @sdt_notes: sdt notes' list
2044 *
2045 * Free up the SDT notes in @sdt_notes.
2046 * Returns the number of SDT notes free'd.
2047 */
2048 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2049 {
2050 struct sdt_note *tmp, *pos;
2051 int nr_free = 0;
2052
2053 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2054 list_del(&pos->note_list);
2055 free(pos->name);
2056 free(pos->provider);
2057 free(pos);
2058 nr_free++;
2059 }
2060 return nr_free;
2061 }
2062
2063 /**
2064 * sdt_notes__get_count: Counts the number of sdt events
2065 * @start: list_head to sdt_notes list
2066 *
2067 * Returns the number of SDT notes in a list
2068 */
2069 int sdt_notes__get_count(struct list_head *start)
2070 {
2071 struct sdt_note *sdt_ptr;
2072 int count = 0;
2073
2074 list_for_each_entry(sdt_ptr, start, note_list)
2075 count++;
2076 return count;
2077 }
2078 #endif
2079
2080 void symbol__elf_init(void)
2081 {
2082 elf_version(EV_CURRENT);
2083 }
CRIS linux kernel tree