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