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Merge tag 'powerpc-5.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc...
[linux/fpc-iii.git] / tools / perf / util / symbol-elf.c
blobf3577f7d72feec7ab14f54ac448052b1310db562
1 // SPDX-License-Identifier: GPL-2.0
2 #include <fcntl.h>
3 #include <stdio.h>
4 #include <errno.h>
5 #include <stdlib.h>
6 #include <string.h>
7 #include <unistd.h>
8 #include <inttypes.h>
9
10 #include "dso.h"
11 #include "map.h"
12 #include "maps.h"
13 #include "symbol.h"
14 #include "symsrc.h"
15 #include "demangle-java.h"
16 #include "demangle-rust.h"
17 #include "machine.h"
18 #include "vdso.h"
19 #include "debug.h"
20 #include "util/copyfile.h"
21 #include <linux/ctype.h>
22 #include <linux/kernel.h>
23 #include <linux/zalloc.h>
24 #include <symbol/kallsyms.h>
25 #include <internal/lib.h>
26
27 #ifndef EM_AARCH64
28 #define EM_AARCH64 183 /* ARM 64 bit */
29 #endif
30
31 #ifndef ELF32_ST_VISIBILITY
32 #define ELF32_ST_VISIBILITY(o) ((o) & 0x03)
33 #endif
34
35 /* For ELF64 the definitions are the same. */
36 #ifndef ELF64_ST_VISIBILITY
37 #define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o)
38 #endif
39
40 /* How to extract information held in the st_other field. */
41 #ifndef GELF_ST_VISIBILITY
42 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
43 #endif
44
45 typedef Elf64_Nhdr GElf_Nhdr;
46
47 #ifndef DMGL_PARAMS
48 #define DMGL_NO_OPTS 0 /* For readability... */
49 #define DMGL_PARAMS (1 << 0) /* Include function args */
50 #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
51 #endif
52
53 #ifdef HAVE_LIBBFD_SUPPORT
54 #define PACKAGE 'perf'
55 #include <bfd.h>
56 #else
57 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
58 extern char *cplus_demangle(const char *, int);
59
60 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
61 {
62 return cplus_demangle(c, i);
63 }
64 #else
65 #ifdef NO_DEMANGLE
66 static inline char *bfd_demangle(void __maybe_unused *v,
67 const char __maybe_unused *c,
68 int __maybe_unused i)
69 {
70 return NULL;
71 }
72 #endif
73 #endif
74 #endif
75
76 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
77 static int elf_getphdrnum(Elf *elf, size_t *dst)
78 {
79 GElf_Ehdr gehdr;
80 GElf_Ehdr *ehdr;
81
82 ehdr = gelf_getehdr(elf, &gehdr);
83 if (!ehdr)
84 return -1;
85
86 *dst = ehdr->e_phnum;
87
88 return 0;
89 }
90 #endif
91
92 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
93 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
94 {
95 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
96 return -1;
97 }
98 #endif
99
100 #ifndef NT_GNU_BUILD_ID
101 #define NT_GNU_BUILD_ID 3
102 #endif
103
104 /**
105 * elf_symtab__for_each_symbol - iterate thru all the symbols
106 *
107 * @syms: struct elf_symtab instance to iterate
108 * @idx: uint32_t idx
109 * @sym: GElf_Sym iterator
110 */
111 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
112 for (idx = 0, gelf_getsym(syms, idx, &sym);\
113 idx < nr_syms; \
114 idx++, gelf_getsym(syms, idx, &sym))
115
116 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
117 {
118 return GELF_ST_TYPE(sym->st_info);
119 }
120
121 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
122 {
123 return GELF_ST_VISIBILITY(sym->st_other);
124 }
125
126 #ifndef STT_GNU_IFUNC
127 #define STT_GNU_IFUNC 10
128 #endif
129
130 static inline int elf_sym__is_function(const GElf_Sym *sym)
131 {
132 return (elf_sym__type(sym) == STT_FUNC ||
133 elf_sym__type(sym) == STT_GNU_IFUNC) &&
134 sym->st_name != 0 &&
135 sym->st_shndx != SHN_UNDEF;
136 }
137
138 static inline bool elf_sym__is_object(const GElf_Sym *sym)
139 {
140 return elf_sym__type(sym) == STT_OBJECT &&
141 sym->st_name != 0 &&
142 sym->st_shndx != SHN_UNDEF;
143 }
144
145 static inline int elf_sym__is_label(const GElf_Sym *sym)
146 {
147 return elf_sym__type(sym) == STT_NOTYPE &&
148 sym->st_name != 0 &&
149 sym->st_shndx != SHN_UNDEF &&
150 sym->st_shndx != SHN_ABS &&
151 elf_sym__visibility(sym) != STV_HIDDEN &&
152 elf_sym__visibility(sym) != STV_INTERNAL;
153 }
154
155 static bool elf_sym__filter(GElf_Sym *sym)
156 {
157 return elf_sym__is_function(sym) || elf_sym__is_object(sym);
158 }
159
160 static inline const char *elf_sym__name(const GElf_Sym *sym,
161 const Elf_Data *symstrs)
162 {
163 return symstrs->d_buf + sym->st_name;
164 }
165
166 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
167 const Elf_Data *secstrs)
168 {
169 return secstrs->d_buf + shdr->sh_name;
170 }
171
172 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
173 const Elf_Data *secstrs)
174 {
175 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
176 }
177
178 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
179 const Elf_Data *secstrs)
180 {
181 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
182 }
183
184 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
185 {
186 return elf_sec__is_text(shdr, secstrs) ||
187 elf_sec__is_data(shdr, secstrs);
188 }
189
190 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
191 {
192 Elf_Scn *sec = NULL;
193 GElf_Shdr shdr;
194 size_t cnt = 1;
195
196 while ((sec = elf_nextscn(elf, sec)) != NULL) {
197 gelf_getshdr(sec, &shdr);
198
199 if ((addr >= shdr.sh_addr) &&
200 (addr < (shdr.sh_addr + shdr.sh_size)))
201 return cnt;
202
203 ++cnt;
204 }
205
206 return -1;
207 }
208
209 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
210 GElf_Shdr *shp, const char *name, size_t *idx)
211 {
212 Elf_Scn *sec = NULL;
213 size_t cnt = 1;
214
215 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
216 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
217 return NULL;
218
219 while ((sec = elf_nextscn(elf, sec)) != NULL) {
220 char *str;
221
222 gelf_getshdr(sec, shp);
223 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
224 if (str && !strcmp(name, str)) {
225 if (idx)
226 *idx = cnt;
227 return sec;
228 }
229 ++cnt;
230 }
231
232 return NULL;
233 }
234
235 static bool want_demangle(bool is_kernel_sym)
236 {
237 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
238 }
239
240 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
241 {
242 int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
243 char *demangled = NULL;
244
245 /*
246 * We need to figure out if the object was created from C++ sources
247 * DWARF DW_compile_unit has this, but we don't always have access
248 * to it...
249 */
250 if (!want_demangle(dso->kernel || kmodule))
251 return demangled;
252
253 demangled = bfd_demangle(NULL, elf_name, demangle_flags);
254 if (demangled == NULL)
255 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
256 else if (rust_is_mangled(demangled))
257 /*
258 * Input to Rust demangling is the BFD-demangled
259 * name which it Rust-demangles in place.
260 */
261 rust_demangle_sym(demangled);
262
263 return demangled;
264 }
265
266 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
267 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
268 idx < nr_entries; \
269 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
270
271 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
272 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
273 idx < nr_entries; \
274 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
275
276 /*
277 * We need to check if we have a .dynsym, so that we can handle the
278 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
279 * .dynsym or .symtab).
280 * And always look at the original dso, not at debuginfo packages, that
281 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
282 */
283 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
284 {
285 uint32_t nr_rel_entries, idx;
286 GElf_Sym sym;
287 u64 plt_offset, plt_header_size, plt_entry_size;
288 GElf_Shdr shdr_plt;
289 struct symbol *f;
290 GElf_Shdr shdr_rel_plt, shdr_dynsym;
291 Elf_Data *reldata, *syms, *symstrs;
292 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
293 size_t dynsym_idx;
294 GElf_Ehdr ehdr;
295 char sympltname[1024];
296 Elf *elf;
297 int nr = 0, symidx, err = 0;
298
299 if (!ss->dynsym)
300 return 0;
301
302 elf = ss->elf;
303 ehdr = ss->ehdr;
304
305 scn_dynsym = ss->dynsym;
306 shdr_dynsym = ss->dynshdr;
307 dynsym_idx = ss->dynsym_idx;
308
309 if (scn_dynsym == NULL)
310 goto out_elf_end;
311
312 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
313 ".rela.plt", NULL);
314 if (scn_plt_rel == NULL) {
315 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
316 ".rel.plt", NULL);
317 if (scn_plt_rel == NULL)
318 goto out_elf_end;
319 }
320
321 err = -1;
322
323 if (shdr_rel_plt.sh_link != dynsym_idx)
324 goto out_elf_end;
325
326 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
327 goto out_elf_end;
328
329 /*
330 * Fetch the relocation section to find the idxes to the GOT
331 * and the symbols in the .dynsym they refer to.
332 */
333 reldata = elf_getdata(scn_plt_rel, NULL);
334 if (reldata == NULL)
335 goto out_elf_end;
336
337 syms = elf_getdata(scn_dynsym, NULL);
338 if (syms == NULL)
339 goto out_elf_end;
340
341 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
342 if (scn_symstrs == NULL)
343 goto out_elf_end;
344
345 symstrs = elf_getdata(scn_symstrs, NULL);
346 if (symstrs == NULL)
347 goto out_elf_end;
348
349 if (symstrs->d_size == 0)
350 goto out_elf_end;
351
352 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
353 plt_offset = shdr_plt.sh_offset;
354 switch (ehdr.e_machine) {
355 case EM_ARM:
356 plt_header_size = 20;
357 plt_entry_size = 12;
358 break;
359
360 case EM_AARCH64:
361 plt_header_size = 32;
362 plt_entry_size = 16;
363 break;
364
365 case EM_SPARC:
366 plt_header_size = 48;
367 plt_entry_size = 12;
368 break;
369
370 case EM_SPARCV9:
371 plt_header_size = 128;
372 plt_entry_size = 32;
373 break;
374
375 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
376 plt_header_size = shdr_plt.sh_entsize;
377 plt_entry_size = shdr_plt.sh_entsize;
378 break;
379 }
380 plt_offset += plt_header_size;
381
382 if (shdr_rel_plt.sh_type == SHT_RELA) {
383 GElf_Rela pos_mem, *pos;
384
385 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
386 nr_rel_entries) {
387 const char *elf_name = NULL;
388 char *demangled = NULL;
389 symidx = GELF_R_SYM(pos->r_info);
390 gelf_getsym(syms, symidx, &sym);
391
392 elf_name = elf_sym__name(&sym, symstrs);
393 demangled = demangle_sym(dso, 0, elf_name);
394 if (demangled != NULL)
395 elf_name = demangled;
396 snprintf(sympltname, sizeof(sympltname),
397 "%s@plt", elf_name);
398 free(demangled);
399
400 f = symbol__new(plt_offset, plt_entry_size,
401 STB_GLOBAL, STT_FUNC, sympltname);
402 if (!f)
403 goto out_elf_end;
404
405 plt_offset += plt_entry_size;
406 symbols__insert(&dso->symbols, f);
407 ++nr;
408 }
409 } else if (shdr_rel_plt.sh_type == SHT_REL) {
410 GElf_Rel pos_mem, *pos;
411 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
412 nr_rel_entries) {
413 const char *elf_name = NULL;
414 char *demangled = NULL;
415 symidx = GELF_R_SYM(pos->r_info);
416 gelf_getsym(syms, symidx, &sym);
417
418 elf_name = elf_sym__name(&sym, symstrs);
419 demangled = demangle_sym(dso, 0, elf_name);
420 if (demangled != NULL)
421 elf_name = demangled;
422 snprintf(sympltname, sizeof(sympltname),
423 "%s@plt", elf_name);
424 free(demangled);
425
426 f = symbol__new(plt_offset, plt_entry_size,
427 STB_GLOBAL, STT_FUNC, sympltname);
428 if (!f)
429 goto out_elf_end;
430
431 plt_offset += plt_entry_size;
432 symbols__insert(&dso->symbols, f);
433 ++nr;
434 }
435 }
436
437 err = 0;
438 out_elf_end:
439 if (err == 0)
440 return nr;
441 pr_debug("%s: problems reading %s PLT info.\n",
442 __func__, dso->long_name);
443 return 0;
444 }
445
446 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
447 {
448 return demangle_sym(dso, kmodule, elf_name);
449 }
450
451 /*
452 * Align offset to 4 bytes as needed for note name and descriptor data.
453 */
454 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
455
456 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
457 {
458 int err = -1;
459 GElf_Ehdr ehdr;
460 GElf_Shdr shdr;
461 Elf_Data *data;
462 Elf_Scn *sec;
463 Elf_Kind ek;
464 void *ptr;
465
466 if (size < BUILD_ID_SIZE)
467 goto out;
468
469 ek = elf_kind(elf);
470 if (ek != ELF_K_ELF)
471 goto out;
472
473 if (gelf_getehdr(elf, &ehdr) == NULL) {
474 pr_err("%s: cannot get elf header.\n", __func__);
475 goto out;
476 }
477
478 /*
479 * Check following sections for notes:
480 * '.note.gnu.build-id'
481 * '.notes'
482 * '.note' (VDSO specific)
483 */
484 do {
485 sec = elf_section_by_name(elf, &ehdr, &shdr,
486 ".note.gnu.build-id", NULL);
487 if (sec)
488 break;
489
490 sec = elf_section_by_name(elf, &ehdr, &shdr,
491 ".notes", NULL);
492 if (sec)
493 break;
494
495 sec = elf_section_by_name(elf, &ehdr, &shdr,
496 ".note", NULL);
497 if (sec)
498 break;
499
500 return err;
501
502 } while (0);
503
504 data = elf_getdata(sec, NULL);
505 if (data == NULL)
506 goto out;
507
508 ptr = data->d_buf;
509 while (ptr < (data->d_buf + data->d_size)) {
510 GElf_Nhdr *nhdr = ptr;
511 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
512 descsz = NOTE_ALIGN(nhdr->n_descsz);
513 const char *name;
514
515 ptr += sizeof(*nhdr);
516 name = ptr;
517 ptr += namesz;
518 if (nhdr->n_type == NT_GNU_BUILD_ID &&
519 nhdr->n_namesz == sizeof("GNU")) {
520 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
521 size_t sz = min(size, descsz);
522 memcpy(bf, ptr, sz);
523 memset(bf + sz, 0, size - sz);
524 err = descsz;
525 break;
526 }
527 }
528 ptr += descsz;
529 }
530
531 out:
532 return err;
533 }
534
535 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT
536
537 static int read_build_id(const char *filename, struct build_id *bid)
538 {
539 size_t size = sizeof(bid->data);
540 int err = -1;
541 bfd *abfd;
542
543 abfd = bfd_openr(filename, NULL);
544 if (!abfd)
545 return -1;
546
547 if (!bfd_check_format(abfd, bfd_object)) {
548 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
549 goto out_close;
550 }
551
552 if (!abfd->build_id || abfd->build_id->size > size)
553 goto out_close;
554
555 memcpy(bid->data, abfd->build_id->data, abfd->build_id->size);
556 memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size);
557 err = bid->size = abfd->build_id->size;
558
559 out_close:
560 bfd_close(abfd);
561 return err;
562 }
563
564 #else // HAVE_LIBBFD_BUILDID_SUPPORT
565
566 static int read_build_id(const char *filename, struct build_id *bid)
567 {
568 size_t size = sizeof(bid->data);
569 int fd, err = -1;
570 Elf *elf;
571
572 if (size < BUILD_ID_SIZE)
573 goto out;
574
575 fd = open(filename, O_RDONLY);
576 if (fd < 0)
577 goto out;
578
579 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
580 if (elf == NULL) {
581 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
582 goto out_close;
583 }
584
585 err = elf_read_build_id(elf, bid->data, size);
586 if (err > 0)
587 bid->size = err;
588
589 elf_end(elf);
590 out_close:
591 close(fd);
592 out:
593 return err;
594 }
595
596 #endif // HAVE_LIBBFD_BUILDID_SUPPORT
597
598 int filename__read_build_id(const char *filename, struct build_id *bid)
599 {
600 struct kmod_path m = { .name = NULL, };
601 char path[PATH_MAX];
602 int err;
603
604 if (!filename)
605 return -EFAULT;
606
607 err = kmod_path__parse(&m, filename);
608 if (err)
609 return -1;
610
611 if (m.comp) {
612 int error = 0, fd;
613
614 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
615 if (fd < 0) {
616 pr_debug("Failed to decompress (error %d) %s\n",
617 error, filename);
618 return -1;
619 }
620 close(fd);
621 filename = path;
622 }
623
624 err = read_build_id(filename, bid);
625
626 if (m.comp)
627 unlink(filename);
628 return err;
629 }
630
631 int sysfs__read_build_id(const char *filename, struct build_id *bid)
632 {
633 size_t size = sizeof(bid->data);
634 int fd, err = -1;
635
636 fd = open(filename, O_RDONLY);
637 if (fd < 0)
638 goto out;
639
640 while (1) {
641 char bf[BUFSIZ];
642 GElf_Nhdr nhdr;
643 size_t namesz, descsz;
644
645 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
646 break;
647
648 namesz = NOTE_ALIGN(nhdr.n_namesz);
649 descsz = NOTE_ALIGN(nhdr.n_descsz);
650 if (nhdr.n_type == NT_GNU_BUILD_ID &&
651 nhdr.n_namesz == sizeof("GNU")) {
652 if (read(fd, bf, namesz) != (ssize_t)namesz)
653 break;
654 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
655 size_t sz = min(descsz, size);
656 if (read(fd, bid->data, sz) == (ssize_t)sz) {
657 memset(bid->data + sz, 0, size - sz);
658 bid->size = sz;
659 err = 0;
660 break;
661 }
662 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
663 break;
664 } else {
665 int n = namesz + descsz;
666
667 if (n > (int)sizeof(bf)) {
668 n = sizeof(bf);
669 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
670 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
671 }
672 if (read(fd, bf, n) != n)
673 break;
674 }
675 }
676 close(fd);
677 out:
678 return err;
679 }
680
681 #ifdef HAVE_LIBBFD_SUPPORT
682
683 int filename__read_debuglink(const char *filename, char *debuglink,
684 size_t size)
685 {
686 int err = -1;
687 asection *section;
688 bfd *abfd;
689
690 abfd = bfd_openr(filename, NULL);
691 if (!abfd)
692 return -1;
693
694 if (!bfd_check_format(abfd, bfd_object)) {
695 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
696 goto out_close;
697 }
698
699 section = bfd_get_section_by_name(abfd, ".gnu_debuglink");
700 if (!section)
701 goto out_close;
702
703 if (section->size > size)
704 goto out_close;
705
706 if (!bfd_get_section_contents(abfd, section, debuglink, 0,
707 section->size))
708 goto out_close;
709
710 err = 0;
711
712 out_close:
713 bfd_close(abfd);
714 return err;
715 }
716
717 #else
718
719 int filename__read_debuglink(const char *filename, char *debuglink,
720 size_t size)
721 {
722 int fd, err = -1;
723 Elf *elf;
724 GElf_Ehdr ehdr;
725 GElf_Shdr shdr;
726 Elf_Data *data;
727 Elf_Scn *sec;
728 Elf_Kind ek;
729
730 fd = open(filename, O_RDONLY);
731 if (fd < 0)
732 goto out;
733
734 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
735 if (elf == NULL) {
736 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
737 goto out_close;
738 }
739
740 ek = elf_kind(elf);
741 if (ek != ELF_K_ELF)
742 goto out_elf_end;
743
744 if (gelf_getehdr(elf, &ehdr) == NULL) {
745 pr_err("%s: cannot get elf header.\n", __func__);
746 goto out_elf_end;
747 }
748
749 sec = elf_section_by_name(elf, &ehdr, &shdr,
750 ".gnu_debuglink", NULL);
751 if (sec == NULL)
752 goto out_elf_end;
753
754 data = elf_getdata(sec, NULL);
755 if (data == NULL)
756 goto out_elf_end;
757
758 /* the start of this section is a zero-terminated string */
759 strncpy(debuglink, data->d_buf, size);
760
761 err = 0;
762
763 out_elf_end:
764 elf_end(elf);
765 out_close:
766 close(fd);
767 out:
768 return err;
769 }
770
771 #endif
772
773 static int dso__swap_init(struct dso *dso, unsigned char eidata)
774 {
775 static unsigned int const endian = 1;
776
777 dso->needs_swap = DSO_SWAP__NO;
778
779 switch (eidata) {
780 case ELFDATA2LSB:
781 /* We are big endian, DSO is little endian. */
782 if (*(unsigned char const *)&endian != 1)
783 dso->needs_swap = DSO_SWAP__YES;
784 break;
785
786 case ELFDATA2MSB:
787 /* We are little endian, DSO is big endian. */
788 if (*(unsigned char const *)&endian != 0)
789 dso->needs_swap = DSO_SWAP__YES;
790 break;
791
792 default:
793 pr_err("unrecognized DSO data encoding %d\n", eidata);
794 return -EINVAL;
795 }
796
797 return 0;
798 }
799
800 bool symsrc__possibly_runtime(struct symsrc *ss)
801 {
802 return ss->dynsym || ss->opdsec;
803 }
804
805 bool symsrc__has_symtab(struct symsrc *ss)
806 {
807 return ss->symtab != NULL;
808 }
809
810 void symsrc__destroy(struct symsrc *ss)
811 {
812 zfree(&ss->name);
813 elf_end(ss->elf);
814 close(ss->fd);
815 }
816
817 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
818 {
819 /*
820 * Usually vmlinux is an ELF file with type ET_EXEC for most
821 * architectures; except Arm64 kernel is linked with option
822 * '-share', so need to check type ET_DYN.
823 */
824 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
825 ehdr.e_type == ET_DYN;
826 }
827
828 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
829 enum dso_binary_type type)
830 {
831 GElf_Ehdr ehdr;
832 Elf *elf;
833 int fd;
834
835 if (dso__needs_decompress(dso)) {
836 fd = dso__decompress_kmodule_fd(dso, name);
837 if (fd < 0)
838 return -1;
839
840 type = dso->symtab_type;
841 } else {
842 fd = open(name, O_RDONLY);
843 if (fd < 0) {
844 dso->load_errno = errno;
845 return -1;
846 }
847 }
848
849 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
850 if (elf == NULL) {
851 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
852 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
853 goto out_close;
854 }
855
856 if (gelf_getehdr(elf, &ehdr) == NULL) {
857 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
858 pr_debug("%s: cannot get elf header.\n", __func__);
859 goto out_elf_end;
860 }
861
862 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
863 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
864 goto out_elf_end;
865 }
866
867 /* Always reject images with a mismatched build-id: */
868 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
869 u8 build_id[BUILD_ID_SIZE];
870 struct build_id bid;
871 int size;
872
873 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);
874 if (size <= 0) {
875 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
876 goto out_elf_end;
877 }
878
879 build_id__init(&bid, build_id, size);
880 if (!dso__build_id_equal(dso, &bid)) {
881 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
882 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
883 goto out_elf_end;
884 }
885 }
886
887 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
888
889 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
890 NULL);
891 if (ss->symshdr.sh_type != SHT_SYMTAB)
892 ss->symtab = NULL;
893
894 ss->dynsym_idx = 0;
895 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
896 &ss->dynsym_idx);
897 if (ss->dynshdr.sh_type != SHT_DYNSYM)
898 ss->dynsym = NULL;
899
900 ss->opdidx = 0;
901 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
902 &ss->opdidx);
903 if (ss->opdshdr.sh_type != SHT_PROGBITS)
904 ss->opdsec = NULL;
905
906 if (dso->kernel == DSO_SPACE__USER)
907 ss->adjust_symbols = true;
908 else
909 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
910
911 ss->name = strdup(name);
912 if (!ss->name) {
913 dso->load_errno = errno;
914 goto out_elf_end;
915 }
916
917 ss->elf = elf;
918 ss->fd = fd;
919 ss->ehdr = ehdr;
920 ss->type = type;
921
922 return 0;
923
924 out_elf_end:
925 elf_end(elf);
926 out_close:
927 close(fd);
928 return -1;
929 }
930
931 /**
932 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
933 * @kmap: kernel maps and relocation reference symbol
934 *
935 * This function returns %true if we are dealing with the kernel maps and the
936 * relocation reference symbol has not yet been found. Otherwise %false is
937 * returned.
938 */
939 static bool ref_reloc_sym_not_found(struct kmap *kmap)
940 {
941 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
942 !kmap->ref_reloc_sym->unrelocated_addr;
943 }
944
945 /**
946 * ref_reloc - kernel relocation offset.
947 * @kmap: kernel maps and relocation reference symbol
948 *
949 * This function returns the offset of kernel addresses as determined by using
950 * the relocation reference symbol i.e. if the kernel has not been relocated
951 * then the return value is zero.
952 */
953 static u64 ref_reloc(struct kmap *kmap)
954 {
955 if (kmap && kmap->ref_reloc_sym &&
956 kmap->ref_reloc_sym->unrelocated_addr)
957 return kmap->ref_reloc_sym->addr -
958 kmap->ref_reloc_sym->unrelocated_addr;
959 return 0;
960 }
961
962 void __weak arch__sym_update(struct symbol *s __maybe_unused,
963 GElf_Sym *sym __maybe_unused) { }
964
965 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
966 GElf_Sym *sym, GElf_Shdr *shdr,
967 struct maps *kmaps, struct kmap *kmap,
968 struct dso **curr_dsop, struct map **curr_mapp,
969 const char *section_name,
970 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
971 {
972 struct dso *curr_dso = *curr_dsop;
973 struct map *curr_map;
974 char dso_name[PATH_MAX];
975
976 /* Adjust symbol to map to file offset */
977 if (adjust_kernel_syms)
978 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
979
980 if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
981 return 0;
982
983 if (strcmp(section_name, ".text") == 0) {
984 /*
985 * The initial kernel mapping is based on
986 * kallsyms and identity maps. Overwrite it to
987 * map to the kernel dso.
988 */
989 if (*remap_kernel && dso->kernel && !kmodule) {
990 *remap_kernel = false;
991 map->start = shdr->sh_addr + ref_reloc(kmap);
992 map->end = map->start + shdr->sh_size;
993 map->pgoff = shdr->sh_offset;
994 map->map_ip = map__map_ip;
995 map->unmap_ip = map__unmap_ip;
996 /* Ensure maps are correctly ordered */
997 if (kmaps) {
998 map__get(map);
999 maps__remove(kmaps, map);
1000 maps__insert(kmaps, map);
1001 map__put(map);
1002 }
1003 }
1004
1005 /*
1006 * The initial module mapping is based on
1007 * /proc/modules mapped to offset zero.
1008 * Overwrite it to map to the module dso.
1009 */
1010 if (*remap_kernel && kmodule) {
1011 *remap_kernel = false;
1012 map->pgoff = shdr->sh_offset;
1013 }
1014
1015 *curr_mapp = map;
1016 *curr_dsop = dso;
1017 return 0;
1018 }
1019
1020 if (!kmap)
1021 return 0;
1022
1023 snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
1024
1025 curr_map = maps__find_by_name(kmaps, dso_name);
1026 if (curr_map == NULL) {
1027 u64 start = sym->st_value;
1028
1029 if (kmodule)
1030 start += map->start + shdr->sh_offset;
1031
1032 curr_dso = dso__new(dso_name);
1033 if (curr_dso == NULL)
1034 return -1;
1035 curr_dso->kernel = dso->kernel;
1036 curr_dso->long_name = dso->long_name;
1037 curr_dso->long_name_len = dso->long_name_len;
1038 curr_map = map__new2(start, curr_dso);
1039 dso__put(curr_dso);
1040 if (curr_map == NULL)
1041 return -1;
1042
1043 if (curr_dso->kernel)
1044 map__kmap(curr_map)->kmaps = kmaps;
1045
1046 if (adjust_kernel_syms) {
1047 curr_map->start = shdr->sh_addr + ref_reloc(kmap);
1048 curr_map->end = curr_map->start + shdr->sh_size;
1049 curr_map->pgoff = shdr->sh_offset;
1050 } else {
1051 curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
1052 }
1053 curr_dso->symtab_type = dso->symtab_type;
1054 maps__insert(kmaps, curr_map);
1055 /*
1056 * Add it before we drop the referece to curr_map, i.e. while
1057 * we still are sure to have a reference to this DSO via
1058 * *curr_map->dso.
1059 */
1060 dsos__add(&kmaps->machine->dsos, curr_dso);
1061 /* kmaps already got it */
1062 map__put(curr_map);
1063 dso__set_loaded(curr_dso);
1064 *curr_mapp = curr_map;
1065 *curr_dsop = curr_dso;
1066 } else
1067 *curr_dsop = curr_map->dso;
1068
1069 return 0;
1070 }
1071
1072 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1073 struct symsrc *runtime_ss, int kmodule)
1074 {
1075 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
1076 struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
1077 struct map *curr_map = map;
1078 struct dso *curr_dso = dso;
1079 Elf_Data *symstrs, *secstrs;
1080 uint32_t nr_syms;
1081 int err = -1;
1082 uint32_t idx;
1083 GElf_Ehdr ehdr;
1084 GElf_Shdr shdr;
1085 GElf_Shdr tshdr;
1086 Elf_Data *syms, *opddata = NULL;
1087 GElf_Sym sym;
1088 Elf_Scn *sec, *sec_strndx;
1089 Elf *elf;
1090 int nr = 0;
1091 bool remap_kernel = false, adjust_kernel_syms = false;
1092
1093 if (kmap && !kmaps)
1094 return -1;
1095
1096 dso->symtab_type = syms_ss->type;
1097 dso->is_64_bit = syms_ss->is_64_bit;
1098 dso->rel = syms_ss->ehdr.e_type == ET_REL;
1099
1100 /*
1101 * Modules may already have symbols from kallsyms, but those symbols
1102 * have the wrong values for the dso maps, so remove them.
1103 */
1104 if (kmodule && syms_ss->symtab)
1105 symbols__delete(&dso->symbols);
1106
1107 if (!syms_ss->symtab) {
1108 /*
1109 * If the vmlinux is stripped, fail so we will fall back
1110 * to using kallsyms. The vmlinux runtime symbols aren't
1111 * of much use.
1112 */
1113 if (dso->kernel)
1114 goto out_elf_end;
1115
1116 syms_ss->symtab = syms_ss->dynsym;
1117 syms_ss->symshdr = syms_ss->dynshdr;
1118 }
1119
1120 elf = syms_ss->elf;
1121 ehdr = syms_ss->ehdr;
1122 sec = syms_ss->symtab;
1123 shdr = syms_ss->symshdr;
1124
1125 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1126 ".text", NULL))
1127 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1128
1129 if (runtime_ss->opdsec)
1130 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1131
1132 syms = elf_getdata(sec, NULL);
1133 if (syms == NULL)
1134 goto out_elf_end;
1135
1136 sec = elf_getscn(elf, shdr.sh_link);
1137 if (sec == NULL)
1138 goto out_elf_end;
1139
1140 symstrs = elf_getdata(sec, NULL);
1141 if (symstrs == NULL)
1142 goto out_elf_end;
1143
1144 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1145 if (sec_strndx == NULL)
1146 goto out_elf_end;
1147
1148 secstrs = elf_getdata(sec_strndx, NULL);
1149 if (secstrs == NULL)
1150 goto out_elf_end;
1151
1152 nr_syms = shdr.sh_size / shdr.sh_entsize;
1153
1154 memset(&sym, 0, sizeof(sym));
1155
1156 /*
1157 * The kernel relocation symbol is needed in advance in order to adjust
1158 * kernel maps correctly.
1159 */
1160 if (ref_reloc_sym_not_found(kmap)) {
1161 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1162 const char *elf_name = elf_sym__name(&sym, symstrs);
1163
1164 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1165 continue;
1166 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1167 map->reloc = kmap->ref_reloc_sym->addr -
1168 kmap->ref_reloc_sym->unrelocated_addr;
1169 break;
1170 }
1171 }
1172
1173 /*
1174 * Handle any relocation of vdso necessary because older kernels
1175 * attempted to prelink vdso to its virtual address.
1176 */
1177 if (dso__is_vdso(dso))
1178 map->reloc = map->start - dso->text_offset;
1179
1180 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1181 /*
1182 * Initial kernel and module mappings do not map to the dso.
1183 * Flag the fixups.
1184 */
1185 if (dso->kernel) {
1186 remap_kernel = true;
1187 adjust_kernel_syms = dso->adjust_symbols;
1188 }
1189 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1190 struct symbol *f;
1191 const char *elf_name = elf_sym__name(&sym, symstrs);
1192 char *demangled = NULL;
1193 int is_label = elf_sym__is_label(&sym);
1194 const char *section_name;
1195 bool used_opd = false;
1196
1197 if (!is_label && !elf_sym__filter(&sym))
1198 continue;
1199
1200 /* Reject ARM ELF "mapping symbols": these aren't unique and
1201 * don't identify functions, so will confuse the profile
1202 * output: */
1203 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1204 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1205 && (elf_name[2] == '\0' || elf_name[2] == '.'))
1206 continue;
1207 }
1208
1209 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1210 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1211 u64 *opd = opddata->d_buf + offset;
1212 sym.st_value = DSO__SWAP(dso, u64, *opd);
1213 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1214 sym.st_value);
1215 used_opd = true;
1216 }
1217 /*
1218 * When loading symbols in a data mapping, ABS symbols (which
1219 * has a value of SHN_ABS in its st_shndx) failed at
1220 * elf_getscn(). And it marks the loading as a failure so
1221 * already loaded symbols cannot be fixed up.
1222 *
1223 * I'm not sure what should be done. Just ignore them for now.
1224 * - Namhyung Kim
1225 */
1226 if (sym.st_shndx == SHN_ABS)
1227 continue;
1228
1229 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1230 if (!sec)
1231 goto out_elf_end;
1232
1233 gelf_getshdr(sec, &shdr);
1234
1235 if (is_label && !elf_sec__filter(&shdr, secstrs))
1236 continue;
1237
1238 section_name = elf_sec__name(&shdr, secstrs);
1239
1240 /* On ARM, symbols for thumb functions have 1 added to
1241 * the symbol address as a flag - remove it */
1242 if ((ehdr.e_machine == EM_ARM) &&
1243 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1244 (sym.st_value & 1))
1245 --sym.st_value;
1246
1247 if (dso->kernel) {
1248 if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1249 section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1250 goto out_elf_end;
1251 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1252 (!used_opd && syms_ss->adjust_symbols)) {
1253 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1254 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1255 (u64)sym.st_value, (u64)shdr.sh_addr,
1256 (u64)shdr.sh_offset);
1257 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1258 }
1259
1260 demangled = demangle_sym(dso, kmodule, elf_name);
1261 if (demangled != NULL)
1262 elf_name = demangled;
1263
1264 f = symbol__new(sym.st_value, sym.st_size,
1265 GELF_ST_BIND(sym.st_info),
1266 GELF_ST_TYPE(sym.st_info), elf_name);
1267 free(demangled);
1268 if (!f)
1269 goto out_elf_end;
1270
1271 arch__sym_update(f, &sym);
1272
1273 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1274 nr++;
1275 }
1276
1277 /*
1278 * For misannotated, zeroed, ASM function sizes.
1279 */
1280 if (nr > 0) {
1281 symbols__fixup_end(&dso->symbols);
1282 symbols__fixup_duplicate(&dso->symbols);
1283 if (kmap) {
1284 /*
1285 * We need to fixup this here too because we create new
1286 * maps here, for things like vsyscall sections.
1287 */
1288 maps__fixup_end(kmaps);
1289 }
1290 }
1291 err = nr;
1292 out_elf_end:
1293 return err;
1294 }
1295
1296 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1297 {
1298 GElf_Phdr phdr;
1299 size_t i, phdrnum;
1300 int err;
1301 u64 sz;
1302
1303 if (elf_getphdrnum(elf, &phdrnum))
1304 return -1;
1305
1306 for (i = 0; i < phdrnum; i++) {
1307 if (gelf_getphdr(elf, i, &phdr) == NULL)
1308 return -1;
1309 if (phdr.p_type != PT_LOAD)
1310 continue;
1311 if (exe) {
1312 if (!(phdr.p_flags & PF_X))
1313 continue;
1314 } else {
1315 if (!(phdr.p_flags & PF_R))
1316 continue;
1317 }
1318 sz = min(phdr.p_memsz, phdr.p_filesz);
1319 if (!sz)
1320 continue;
1321 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1322 if (err)
1323 return err;
1324 }
1325 return 0;
1326 }
1327
1328 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1329 bool *is_64_bit)
1330 {
1331 int err;
1332 Elf *elf;
1333
1334 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1335 if (elf == NULL)
1336 return -1;
1337
1338 if (is_64_bit)
1339 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1340
1341 err = elf_read_maps(elf, exe, mapfn, data);
1342
1343 elf_end(elf);
1344 return err;
1345 }
1346
1347 enum dso_type dso__type_fd(int fd)
1348 {
1349 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1350 GElf_Ehdr ehdr;
1351 Elf_Kind ek;
1352 Elf *elf;
1353
1354 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1355 if (elf == NULL)
1356 goto out;
1357
1358 ek = elf_kind(elf);
1359 if (ek != ELF_K_ELF)
1360 goto out_end;
1361
1362 if (gelf_getclass(elf) == ELFCLASS64) {
1363 dso_type = DSO__TYPE_64BIT;
1364 goto out_end;
1365 }
1366
1367 if (gelf_getehdr(elf, &ehdr) == NULL)
1368 goto out_end;
1369
1370 if (ehdr.e_machine == EM_X86_64)
1371 dso_type = DSO__TYPE_X32BIT;
1372 else
1373 dso_type = DSO__TYPE_32BIT;
1374 out_end:
1375 elf_end(elf);
1376 out:
1377 return dso_type;
1378 }
1379
1380 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1381 {
1382 ssize_t r;
1383 size_t n;
1384 int err = -1;
1385 char *buf = malloc(page_size);
1386
1387 if (buf == NULL)
1388 return -1;
1389
1390 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1391 goto out;
1392
1393 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1394 goto out;
1395
1396 while (len) {
1397 n = page_size;
1398 if (len < n)
1399 n = len;
1400 /* Use read because mmap won't work on proc files */
1401 r = read(from, buf, n);
1402 if (r < 0)
1403 goto out;
1404 if (!r)
1405 break;
1406 n = r;
1407 r = write(to, buf, n);
1408 if (r < 0)
1409 goto out;
1410 if ((size_t)r != n)
1411 goto out;
1412 len -= n;
1413 }
1414
1415 err = 0;
1416 out:
1417 free(buf);
1418 return err;
1419 }
1420
1421 struct kcore {
1422 int fd;
1423 int elfclass;
1424 Elf *elf;
1425 GElf_Ehdr ehdr;
1426 };
1427
1428 static int kcore__open(struct kcore *kcore, const char *filename)
1429 {
1430 GElf_Ehdr *ehdr;
1431
1432 kcore->fd = open(filename, O_RDONLY);
1433 if (kcore->fd == -1)
1434 return -1;
1435
1436 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1437 if (!kcore->elf)
1438 goto out_close;
1439
1440 kcore->elfclass = gelf_getclass(kcore->elf);
1441 if (kcore->elfclass == ELFCLASSNONE)
1442 goto out_end;
1443
1444 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1445 if (!ehdr)
1446 goto out_end;
1447
1448 return 0;
1449
1450 out_end:
1451 elf_end(kcore->elf);
1452 out_close:
1453 close(kcore->fd);
1454 return -1;
1455 }
1456
1457 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1458 bool temp)
1459 {
1460 kcore->elfclass = elfclass;
1461
1462 if (temp)
1463 kcore->fd = mkstemp(filename);
1464 else
1465 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1466 if (kcore->fd == -1)
1467 return -1;
1468
1469 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1470 if (!kcore->elf)
1471 goto out_close;
1472
1473 if (!gelf_newehdr(kcore->elf, elfclass))
1474 goto out_end;
1475
1476 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1477
1478 return 0;
1479
1480 out_end:
1481 elf_end(kcore->elf);
1482 out_close:
1483 close(kcore->fd);
1484 unlink(filename);
1485 return -1;
1486 }
1487
1488 static void kcore__close(struct kcore *kcore)
1489 {
1490 elf_end(kcore->elf);
1491 close(kcore->fd);
1492 }
1493
1494 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1495 {
1496 GElf_Ehdr *ehdr = &to->ehdr;
1497 GElf_Ehdr *kehdr = &from->ehdr;
1498
1499 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1500 ehdr->e_type = kehdr->e_type;
1501 ehdr->e_machine = kehdr->e_machine;
1502 ehdr->e_version = kehdr->e_version;
1503 ehdr->e_entry = 0;
1504 ehdr->e_shoff = 0;
1505 ehdr->e_flags = kehdr->e_flags;
1506 ehdr->e_phnum = count;
1507 ehdr->e_shentsize = 0;
1508 ehdr->e_shnum = 0;
1509 ehdr->e_shstrndx = 0;
1510
1511 if (from->elfclass == ELFCLASS32) {
1512 ehdr->e_phoff = sizeof(Elf32_Ehdr);
1513 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
1514 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1515 } else {
1516 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1517 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1518 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1519 }
1520
1521 if (!gelf_update_ehdr(to->elf, ehdr))
1522 return -1;
1523
1524 if (!gelf_newphdr(to->elf, count))
1525 return -1;
1526
1527 return 0;
1528 }
1529
1530 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1531 u64 addr, u64 len)
1532 {
1533 GElf_Phdr phdr = {
1534 .p_type = PT_LOAD,
1535 .p_flags = PF_R | PF_W | PF_X,
1536 .p_offset = offset,
1537 .p_vaddr = addr,
1538 .p_paddr = 0,
1539 .p_filesz = len,
1540 .p_memsz = len,
1541 .p_align = page_size,
1542 };
1543
1544 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1545 return -1;
1546
1547 return 0;
1548 }
1549
1550 static off_t kcore__write(struct kcore *kcore)
1551 {
1552 return elf_update(kcore->elf, ELF_C_WRITE);
1553 }
1554
1555 struct phdr_data {
1556 off_t offset;
1557 off_t rel;
1558 u64 addr;
1559 u64 len;
1560 struct list_head node;
1561 struct phdr_data *remaps;
1562 };
1563
1564 struct sym_data {
1565 u64 addr;
1566 struct list_head node;
1567 };
1568
1569 struct kcore_copy_info {
1570 u64 stext;
1571 u64 etext;
1572 u64 first_symbol;
1573 u64 last_symbol;
1574 u64 first_module;
1575 u64 first_module_symbol;
1576 u64 last_module_symbol;
1577 size_t phnum;
1578 struct list_head phdrs;
1579 struct list_head syms;
1580 };
1581
1582 #define kcore_copy__for_each_phdr(k, p) \
1583 list_for_each_entry((p), &(k)->phdrs, node)
1584
1585 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1586 {
1587 struct phdr_data *p = zalloc(sizeof(*p));
1588
1589 if (p) {
1590 p->addr = addr;
1591 p->len = len;
1592 p->offset = offset;
1593 }
1594
1595 return p;
1596 }
1597
1598 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1599 u64 addr, u64 len,
1600 off_t offset)
1601 {
1602 struct phdr_data *p = phdr_data__new(addr, len, offset);
1603
1604 if (p)
1605 list_add_tail(&p->node, &kci->phdrs);
1606
1607 return p;
1608 }
1609
1610 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1611 {
1612 struct phdr_data *p, *tmp;
1613
1614 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1615 list_del_init(&p->node);
1616 free(p);
1617 }
1618 }
1619
1620 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1621 u64 addr)
1622 {
1623 struct sym_data *s = zalloc(sizeof(*s));
1624
1625 if (s) {
1626 s->addr = addr;
1627 list_add_tail(&s->node, &kci->syms);
1628 }
1629
1630 return s;
1631 }
1632
1633 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1634 {
1635 struct sym_data *s, *tmp;
1636
1637 list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1638 list_del_init(&s->node);
1639 free(s);
1640 }
1641 }
1642
1643 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1644 u64 start)
1645 {
1646 struct kcore_copy_info *kci = arg;
1647
1648 if (!kallsyms__is_function(type))
1649 return 0;
1650
1651 if (strchr(name, '[')) {
1652 if (!kci->first_module_symbol || start < kci->first_module_symbol)
1653 kci->first_module_symbol = start;
1654 if (start > kci->last_module_symbol)
1655 kci->last_module_symbol = start;
1656 return 0;
1657 }
1658
1659 if (!kci->first_symbol || start < kci->first_symbol)
1660 kci->first_symbol = start;
1661
1662 if (!kci->last_symbol || start > kci->last_symbol)
1663 kci->last_symbol = start;
1664
1665 if (!strcmp(name, "_stext")) {
1666 kci->stext = start;
1667 return 0;
1668 }
1669
1670 if (!strcmp(name, "_etext")) {
1671 kci->etext = start;
1672 return 0;
1673 }
1674
1675 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1676 return -1;
1677
1678 return 0;
1679 }
1680
1681 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1682 const char *dir)
1683 {
1684 char kallsyms_filename[PATH_MAX];
1685
1686 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1687
1688 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1689 return -1;
1690
1691 if (kallsyms__parse(kallsyms_filename, kci,
1692 kcore_copy__process_kallsyms) < 0)
1693 return -1;
1694
1695 return 0;
1696 }
1697
1698 static int kcore_copy__process_modules(void *arg,
1699 const char *name __maybe_unused,
1700 u64 start, u64 size __maybe_unused)
1701 {
1702 struct kcore_copy_info *kci = arg;
1703
1704 if (!kci->first_module || start < kci->first_module)
1705 kci->first_module = start;
1706
1707 return 0;
1708 }
1709
1710 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1711 const char *dir)
1712 {
1713 char modules_filename[PATH_MAX];
1714
1715 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1716
1717 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1718 return -1;
1719
1720 if (modules__parse(modules_filename, kci,
1721 kcore_copy__process_modules) < 0)
1722 return -1;
1723
1724 return 0;
1725 }
1726
1727 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1728 u64 pgoff, u64 s, u64 e)
1729 {
1730 u64 len, offset;
1731
1732 if (s < start || s >= end)
1733 return 0;
1734
1735 offset = (s - start) + pgoff;
1736 len = e < end ? e - s : end - s;
1737
1738 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1739 }
1740
1741 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1742 {
1743 struct kcore_copy_info *kci = data;
1744 u64 end = start + len;
1745 struct sym_data *sdat;
1746
1747 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1748 return -1;
1749
1750 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1751 kci->last_module_symbol))
1752 return -1;
1753
1754 list_for_each_entry(sdat, &kci->syms, node) {
1755 u64 s = round_down(sdat->addr, page_size);
1756
1757 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1758 return -1;
1759 }
1760
1761 return 0;
1762 }
1763
1764 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1765 {
1766 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1767 return -1;
1768
1769 return 0;
1770 }
1771
1772 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1773 {
1774 struct phdr_data *p, *k = NULL;
1775 u64 kend;
1776
1777 if (!kci->stext)
1778 return;
1779
1780 /* Find phdr that corresponds to the kernel map (contains stext) */
1781 kcore_copy__for_each_phdr(kci, p) {
1782 u64 pend = p->addr + p->len - 1;
1783
1784 if (p->addr <= kci->stext && pend >= kci->stext) {
1785 k = p;
1786 break;
1787 }
1788 }
1789
1790 if (!k)
1791 return;
1792
1793 kend = k->offset + k->len;
1794
1795 /* Find phdrs that remap the kernel */
1796 kcore_copy__for_each_phdr(kci, p) {
1797 u64 pend = p->offset + p->len;
1798
1799 if (p == k)
1800 continue;
1801
1802 if (p->offset >= k->offset && pend <= kend)
1803 p->remaps = k;
1804 }
1805 }
1806
1807 static void kcore_copy__layout(struct kcore_copy_info *kci)
1808 {
1809 struct phdr_data *p;
1810 off_t rel = 0;
1811
1812 kcore_copy__find_remaps(kci);
1813
1814 kcore_copy__for_each_phdr(kci, p) {
1815 if (!p->remaps) {
1816 p->rel = rel;
1817 rel += p->len;
1818 }
1819 kci->phnum += 1;
1820 }
1821
1822 kcore_copy__for_each_phdr(kci, p) {
1823 struct phdr_data *k = p->remaps;
1824
1825 if (k)
1826 p->rel = p->offset - k->offset + k->rel;
1827 }
1828 }
1829
1830 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1831 Elf *elf)
1832 {
1833 if (kcore_copy__parse_kallsyms(kci, dir))
1834 return -1;
1835
1836 if (kcore_copy__parse_modules(kci, dir))
1837 return -1;
1838
1839 if (kci->stext)
1840 kci->stext = round_down(kci->stext, page_size);
1841 else
1842 kci->stext = round_down(kci->first_symbol, page_size);
1843
1844 if (kci->etext) {
1845 kci->etext = round_up(kci->etext, page_size);
1846 } else if (kci->last_symbol) {
1847 kci->etext = round_up(kci->last_symbol, page_size);
1848 kci->etext += page_size;
1849 }
1850
1851 if (kci->first_module_symbol &&
1852 (!kci->first_module || kci->first_module_symbol < kci->first_module))
1853 kci->first_module = kci->first_module_symbol;
1854
1855 kci->first_module = round_down(kci->first_module, page_size);
1856
1857 if (kci->last_module_symbol) {
1858 kci->last_module_symbol = round_up(kci->last_module_symbol,
1859 page_size);
1860 kci->last_module_symbol += page_size;
1861 }
1862
1863 if (!kci->stext || !kci->etext)
1864 return -1;
1865
1866 if (kci->first_module && !kci->last_module_symbol)
1867 return -1;
1868
1869 if (kcore_copy__read_maps(kci, elf))
1870 return -1;
1871
1872 kcore_copy__layout(kci);
1873
1874 return 0;
1875 }
1876
1877 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1878 const char *name)
1879 {
1880 char from_filename[PATH_MAX];
1881 char to_filename[PATH_MAX];
1882
1883 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1884 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1885
1886 return copyfile_mode(from_filename, to_filename, 0400);
1887 }
1888
1889 static int kcore_copy__unlink(const char *dir, const char *name)
1890 {
1891 char filename[PATH_MAX];
1892
1893 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1894
1895 return unlink(filename);
1896 }
1897
1898 static int kcore_copy__compare_fds(int from, int to)
1899 {
1900 char *buf_from;
1901 char *buf_to;
1902 ssize_t ret;
1903 size_t len;
1904 int err = -1;
1905
1906 buf_from = malloc(page_size);
1907 buf_to = malloc(page_size);
1908 if (!buf_from || !buf_to)
1909 goto out;
1910
1911 while (1) {
1912 /* Use read because mmap won't work on proc files */
1913 ret = read(from, buf_from, page_size);
1914 if (ret < 0)
1915 goto out;
1916
1917 if (!ret)
1918 break;
1919
1920 len = ret;
1921
1922 if (readn(to, buf_to, len) != (int)len)
1923 goto out;
1924
1925 if (memcmp(buf_from, buf_to, len))
1926 goto out;
1927 }
1928
1929 err = 0;
1930 out:
1931 free(buf_to);
1932 free(buf_from);
1933 return err;
1934 }
1935
1936 static int kcore_copy__compare_files(const char *from_filename,
1937 const char *to_filename)
1938 {
1939 int from, to, err = -1;
1940
1941 from = open(from_filename, O_RDONLY);
1942 if (from < 0)
1943 return -1;
1944
1945 to = open(to_filename, O_RDONLY);
1946 if (to < 0)
1947 goto out_close_from;
1948
1949 err = kcore_copy__compare_fds(from, to);
1950
1951 close(to);
1952 out_close_from:
1953 close(from);
1954 return err;
1955 }
1956
1957 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1958 const char *name)
1959 {
1960 char from_filename[PATH_MAX];
1961 char to_filename[PATH_MAX];
1962
1963 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1964 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1965
1966 return kcore_copy__compare_files(from_filename, to_filename);
1967 }
1968
1969 /**
1970 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1971 * @from_dir: from directory
1972 * @to_dir: to directory
1973 *
1974 * This function copies kallsyms, modules and kcore files from one directory to
1975 * another. kallsyms and modules are copied entirely. Only code segments are
1976 * copied from kcore. It is assumed that two segments suffice: one for the
1977 * kernel proper and one for all the modules. The code segments are determined
1978 * from kallsyms and modules files. The kernel map starts at _stext or the
1979 * lowest function symbol, and ends at _etext or the highest function symbol.
1980 * The module map starts at the lowest module address and ends at the highest
1981 * module symbol. Start addresses are rounded down to the nearest page. End
1982 * addresses are rounded up to the nearest page. An extra page is added to the
1983 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1984 * symbol too. Because it contains only code sections, the resulting kcore is
1985 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1986 * is not the same for the kernel map and the modules map. That happens because
1987 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1988 * kallsyms and modules files are compared with their copies to check that
1989 * modules have not been loaded or unloaded while the copies were taking place.
1990 *
1991 * Return: %0 on success, %-1 on failure.
1992 */
1993 int kcore_copy(const char *from_dir, const char *to_dir)
1994 {
1995 struct kcore kcore;
1996 struct kcore extract;
1997 int idx = 0, err = -1;
1998 off_t offset, sz;
1999 struct kcore_copy_info kci = { .stext = 0, };
2000 char kcore_filename[PATH_MAX];
2001 char extract_filename[PATH_MAX];
2002 struct phdr_data *p;
2003
2004 INIT_LIST_HEAD(&kci.phdrs);
2005 INIT_LIST_HEAD(&kci.syms);
2006
2007 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
2008 return -1;
2009
2010 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
2011 goto out_unlink_kallsyms;
2012
2013 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
2014 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
2015
2016 if (kcore__open(&kcore, kcore_filename))
2017 goto out_unlink_modules;
2018
2019 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
2020 goto out_kcore_close;
2021
2022 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
2023 goto out_kcore_close;
2024
2025 if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
2026 goto out_extract_close;
2027
2028 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
2029 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
2030 offset = round_up(offset, page_size);
2031
2032 kcore_copy__for_each_phdr(&kci, p) {
2033 off_t offs = p->rel + offset;
2034
2035 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
2036 goto out_extract_close;
2037 }
2038
2039 sz = kcore__write(&extract);
2040 if (sz < 0 || sz > offset)
2041 goto out_extract_close;
2042
2043 kcore_copy__for_each_phdr(&kci, p) {
2044 off_t offs = p->rel + offset;
2045
2046 if (p->remaps)
2047 continue;
2048 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
2049 goto out_extract_close;
2050 }
2051
2052 if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
2053 goto out_extract_close;
2054
2055 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
2056 goto out_extract_close;
2057
2058 err = 0;
2059
2060 out_extract_close:
2061 kcore__close(&extract);
2062 if (err)
2063 unlink(extract_filename);
2064 out_kcore_close:
2065 kcore__close(&kcore);
2066 out_unlink_modules:
2067 if (err)
2068 kcore_copy__unlink(to_dir, "modules");
2069 out_unlink_kallsyms:
2070 if (err)
2071 kcore_copy__unlink(to_dir, "kallsyms");
2072
2073 kcore_copy__free_phdrs(&kci);
2074 kcore_copy__free_syms(&kci);
2075
2076 return err;
2077 }
2078
2079 int kcore_extract__create(struct kcore_extract *kce)
2080 {
2081 struct kcore kcore;
2082 struct kcore extract;
2083 size_t count = 1;
2084 int idx = 0, err = -1;
2085 off_t offset = page_size, sz;
2086
2087 if (kcore__open(&kcore, kce->kcore_filename))
2088 return -1;
2089
2090 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
2091 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
2092 goto out_kcore_close;
2093
2094 if (kcore__copy_hdr(&kcore, &extract, count))
2095 goto out_extract_close;
2096
2097 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
2098 goto out_extract_close;
2099
2100 sz = kcore__write(&extract);
2101 if (sz < 0 || sz > offset)
2102 goto out_extract_close;
2103
2104 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
2105 goto out_extract_close;
2106
2107 err = 0;
2108
2109 out_extract_close:
2110 kcore__close(&extract);
2111 if (err)
2112 unlink(kce->extract_filename);
2113 out_kcore_close:
2114 kcore__close(&kcore);
2115
2116 return err;
2117 }
2118
2119 void kcore_extract__delete(struct kcore_extract *kce)
2120 {
2121 unlink(kce->extract_filename);
2122 }
2123
2124 #ifdef HAVE_GELF_GETNOTE_SUPPORT
2125
2126 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2127 {
2128 if (!base_off)
2129 return;
2130
2131 if (tmp->bit32)
2132 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2133 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2134 tmp->addr.a32[SDT_NOTE_IDX_BASE];
2135 else
2136 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2137 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2138 tmp->addr.a64[SDT_NOTE_IDX_BASE];
2139 }
2140
2141 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2142 GElf_Addr base_off)
2143 {
2144 if (!base_off)
2145 return;
2146
2147 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2148 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2149 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2150 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2151 }
2152
2153 /**
2154 * populate_sdt_note : Parse raw data and identify SDT note
2155 * @elf: elf of the opened file
2156 * @data: raw data of a section with description offset applied
2157 * @len: note description size
2158 * @type: type of the note
2159 * @sdt_notes: List to add the SDT note
2160 *
2161 * Responsible for parsing the @data in section .note.stapsdt in @elf and
2162 * if its an SDT note, it appends to @sdt_notes list.
2163 */
2164 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2165 struct list_head *sdt_notes)
2166 {
2167 const char *provider, *name, *args;
2168 struct sdt_note *tmp = NULL;
2169 GElf_Ehdr ehdr;
2170 GElf_Shdr shdr;
2171 int ret = -EINVAL;
2172
2173 union {
2174 Elf64_Addr a64[NR_ADDR];
2175 Elf32_Addr a32[NR_ADDR];
2176 } buf;
2177
2178 Elf_Data dst = {
2179 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2180 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2181 .d_off = 0, .d_align = 0
2182 };
2183 Elf_Data src = {
2184 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2185 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2186 .d_align = 0
2187 };
2188
2189 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2190 if (!tmp) {
2191 ret = -ENOMEM;
2192 goto out_err;
2193 }
2194
2195 INIT_LIST_HEAD(&tmp->note_list);
2196
2197 if (len < dst.d_size + 3)
2198 goto out_free_note;
2199
2200 /* Translation from file representation to memory representation */
2201 if (gelf_xlatetom(*elf, &dst, &src,
2202 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2203 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2204 goto out_free_note;
2205 }
2206
2207 /* Populate the fields of sdt_note */
2208 provider = data + dst.d_size;
2209
2210 name = (const char *)memchr(provider, '\0', data + len - provider);
2211 if (name++ == NULL)
2212 goto out_free_note;
2213
2214 tmp->provider = strdup(provider);
2215 if (!tmp->provider) {
2216 ret = -ENOMEM;
2217 goto out_free_note;
2218 }
2219 tmp->name = strdup(name);
2220 if (!tmp->name) {
2221 ret = -ENOMEM;
2222 goto out_free_prov;
2223 }
2224
2225 args = memchr(name, '\0', data + len - name);
2226
2227 /*
2228 * There is no argument if:
2229 * - We reached the end of the note;
2230 * - There is not enough room to hold a potential string;
2231 * - The argument string is empty or just contains ':'.
2232 */
2233 if (args == NULL || data + len - args < 2 ||
2234 args[1] == ':' || args[1] == '\0')
2235 tmp->args = NULL;
2236 else {
2237 tmp->args = strdup(++args);
2238 if (!tmp->args) {
2239 ret = -ENOMEM;
2240 goto out_free_name;
2241 }
2242 }
2243
2244 if (gelf_getclass(*elf) == ELFCLASS32) {
2245 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2246 tmp->bit32 = true;
2247 } else {
2248 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2249 tmp->bit32 = false;
2250 }
2251
2252 if (!gelf_getehdr(*elf, &ehdr)) {
2253 pr_debug("%s : cannot get elf header.\n", __func__);
2254 ret = -EBADF;
2255 goto out_free_args;
2256 }
2257
2258 /* Adjust the prelink effect :
2259 * Find out the .stapsdt.base section.
2260 * This scn will help us to handle prelinking (if present).
2261 * Compare the retrieved file offset of the base section with the
2262 * base address in the description of the SDT note. If its different,
2263 * then accordingly, adjust the note location.
2264 */
2265 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2266 sdt_adjust_loc(tmp, shdr.sh_offset);
2267
2268 /* Adjust reference counter offset */
2269 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2270 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2271
2272 list_add_tail(&tmp->note_list, sdt_notes);
2273 return 0;
2274
2275 out_free_args:
2276 zfree(&tmp->args);
2277 out_free_name:
2278 zfree(&tmp->name);
2279 out_free_prov:
2280 zfree(&tmp->provider);
2281 out_free_note:
2282 free(tmp);
2283 out_err:
2284 return ret;
2285 }
2286
2287 /**
2288 * construct_sdt_notes_list : constructs a list of SDT notes
2289 * @elf : elf to look into
2290 * @sdt_notes : empty list_head
2291 *
2292 * Scans the sections in 'elf' for the section
2293 * .note.stapsdt. It, then calls populate_sdt_note to find
2294 * out the SDT events and populates the 'sdt_notes'.
2295 */
2296 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2297 {
2298 GElf_Ehdr ehdr;
2299 Elf_Scn *scn = NULL;
2300 Elf_Data *data;
2301 GElf_Shdr shdr;
2302 size_t shstrndx, next;
2303 GElf_Nhdr nhdr;
2304 size_t name_off, desc_off, offset;
2305 int ret = 0;
2306
2307 if (gelf_getehdr(elf, &ehdr) == NULL) {
2308 ret = -EBADF;
2309 goto out_ret;
2310 }
2311 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2312 ret = -EBADF;
2313 goto out_ret;
2314 }
2315
2316 /* Look for the required section */
2317 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2318 if (!scn) {
2319 ret = -ENOENT;
2320 goto out_ret;
2321 }
2322
2323 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2324 ret = -ENOENT;
2325 goto out_ret;
2326 }
2327
2328 data = elf_getdata(scn, NULL);
2329
2330 /* Get the SDT notes */
2331 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2332 &desc_off)) > 0; offset = next) {
2333 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2334 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2335 sizeof(SDT_NOTE_NAME))) {
2336 /* Check the type of the note */
2337 if (nhdr.n_type != SDT_NOTE_TYPE)
2338 goto out_ret;
2339
2340 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2341 nhdr.n_descsz, sdt_notes);
2342 if (ret < 0)
2343 goto out_ret;
2344 }
2345 }
2346 if (list_empty(sdt_notes))
2347 ret = -ENOENT;
2348
2349 out_ret:
2350 return ret;
2351 }
2352
2353 /**
2354 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2355 * @head : empty list_head
2356 * @target : file to find SDT notes from
2357 *
2358 * This opens the file, initializes
2359 * the ELF and then calls construct_sdt_notes_list.
2360 */
2361 int get_sdt_note_list(struct list_head *head, const char *target)
2362 {
2363 Elf *elf;
2364 int fd, ret;
2365
2366 fd = open(target, O_RDONLY);
2367 if (fd < 0)
2368 return -EBADF;
2369
2370 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2371 if (!elf) {
2372 ret = -EBADF;
2373 goto out_close;
2374 }
2375 ret = construct_sdt_notes_list(elf, head);
2376 elf_end(elf);
2377 out_close:
2378 close(fd);
2379 return ret;
2380 }
2381
2382 /**
2383 * cleanup_sdt_note_list : free the sdt notes' list
2384 * @sdt_notes: sdt notes' list
2385 *
2386 * Free up the SDT notes in @sdt_notes.
2387 * Returns the number of SDT notes free'd.
2388 */
2389 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2390 {
2391 struct sdt_note *tmp, *pos;
2392 int nr_free = 0;
2393
2394 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2395 list_del_init(&pos->note_list);
2396 zfree(&pos->name);
2397 zfree(&pos->provider);
2398 free(pos);
2399 nr_free++;
2400 }
2401 return nr_free;
2402 }
2403
2404 /**
2405 * sdt_notes__get_count: Counts the number of sdt events
2406 * @start: list_head to sdt_notes list
2407 *
2408 * Returns the number of SDT notes in a list
2409 */
2410 int sdt_notes__get_count(struct list_head *start)
2411 {
2412 struct sdt_note *sdt_ptr;
2413 int count = 0;
2414
2415 list_for_each_entry(sdt_ptr, start, note_list)
2416 count++;
2417 return count;
2418 }
2419 #endif
2420
2421 void symbol__elf_init(void)
2422 {
2423 elf_version(EV_CURRENT);
2424 }
Linux with added FPC-III support