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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / tools / perf / util / symbol-elf.c
blob1965aefccb022b98f8362da8b03815a07d5c250c
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_CPLUS_DEMANGLE_SUPPORT
54 extern char *cplus_demangle(const char *, int);
55
56 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
57 {
58 return cplus_demangle(c, i);
59 }
60 #else
61 #ifdef NO_DEMANGLE
62 static inline char *bfd_demangle(void __maybe_unused *v,
63 const char __maybe_unused *c,
64 int __maybe_unused i)
65 {
66 return NULL;
67 }
68 #else
69 #define PACKAGE 'perf'
70 #include <bfd.h>
71 #endif
72 #endif
73
74 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
75 static int elf_getphdrnum(Elf *elf, size_t *dst)
76 {
77 GElf_Ehdr gehdr;
78 GElf_Ehdr *ehdr;
79
80 ehdr = gelf_getehdr(elf, &gehdr);
81 if (!ehdr)
82 return -1;
83
84 *dst = ehdr->e_phnum;
85
86 return 0;
87 }
88 #endif
89
90 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
91 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
92 {
93 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
94 return -1;
95 }
96 #endif
97
98 #ifndef NT_GNU_BUILD_ID
99 #define NT_GNU_BUILD_ID 3
100 #endif
101
102 /**
103 * elf_symtab__for_each_symbol - iterate thru all the symbols
104 *
105 * @syms: struct elf_symtab instance to iterate
106 * @idx: uint32_t idx
107 * @sym: GElf_Sym iterator
108 */
109 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
110 for (idx = 0, gelf_getsym(syms, idx, &sym);\
111 idx < nr_syms; \
112 idx++, gelf_getsym(syms, idx, &sym))
113
114 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
115 {
116 return GELF_ST_TYPE(sym->st_info);
117 }
118
119 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
120 {
121 return GELF_ST_VISIBILITY(sym->st_other);
122 }
123
124 #ifndef STT_GNU_IFUNC
125 #define STT_GNU_IFUNC 10
126 #endif
127
128 static inline int elf_sym__is_function(const GElf_Sym *sym)
129 {
130 return (elf_sym__type(sym) == STT_FUNC ||
131 elf_sym__type(sym) == STT_GNU_IFUNC) &&
132 sym->st_name != 0 &&
133 sym->st_shndx != SHN_UNDEF;
134 }
135
136 static inline bool elf_sym__is_object(const GElf_Sym *sym)
137 {
138 return elf_sym__type(sym) == STT_OBJECT &&
139 sym->st_name != 0 &&
140 sym->st_shndx != SHN_UNDEF;
141 }
142
143 static inline int elf_sym__is_label(const GElf_Sym *sym)
144 {
145 return elf_sym__type(sym) == STT_NOTYPE &&
146 sym->st_name != 0 &&
147 sym->st_shndx != SHN_UNDEF &&
148 sym->st_shndx != SHN_ABS &&
149 elf_sym__visibility(sym) != STV_HIDDEN &&
150 elf_sym__visibility(sym) != STV_INTERNAL;
151 }
152
153 static bool elf_sym__filter(GElf_Sym *sym)
154 {
155 return elf_sym__is_function(sym) || elf_sym__is_object(sym);
156 }
157
158 static inline const char *elf_sym__name(const GElf_Sym *sym,
159 const Elf_Data *symstrs)
160 {
161 return symstrs->d_buf + sym->st_name;
162 }
163
164 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
165 const Elf_Data *secstrs)
166 {
167 return secstrs->d_buf + shdr->sh_name;
168 }
169
170 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
171 const Elf_Data *secstrs)
172 {
173 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
174 }
175
176 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
177 const Elf_Data *secstrs)
178 {
179 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
180 }
181
182 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
183 {
184 return elf_sec__is_text(shdr, secstrs) ||
185 elf_sec__is_data(shdr, secstrs);
186 }
187
188 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
189 {
190 Elf_Scn *sec = NULL;
191 GElf_Shdr shdr;
192 size_t cnt = 1;
193
194 while ((sec = elf_nextscn(elf, sec)) != NULL) {
195 gelf_getshdr(sec, &shdr);
196
197 if ((addr >= shdr.sh_addr) &&
198 (addr < (shdr.sh_addr + shdr.sh_size)))
199 return cnt;
200
201 ++cnt;
202 }
203
204 return -1;
205 }
206
207 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
208 GElf_Shdr *shp, const char *name, size_t *idx)
209 {
210 Elf_Scn *sec = NULL;
211 size_t cnt = 1;
212
213 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
214 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
215 return NULL;
216
217 while ((sec = elf_nextscn(elf, sec)) != NULL) {
218 char *str;
219
220 gelf_getshdr(sec, shp);
221 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
222 if (str && !strcmp(name, str)) {
223 if (idx)
224 *idx = cnt;
225 return sec;
226 }
227 ++cnt;
228 }
229
230 return NULL;
231 }
232
233 static bool want_demangle(bool is_kernel_sym)
234 {
235 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
236 }
237
238 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
239 {
240 int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
241 char *demangled = NULL;
242
243 /*
244 * We need to figure out if the object was created from C++ sources
245 * DWARF DW_compile_unit has this, but we don't always have access
246 * to it...
247 */
248 if (!want_demangle(dso->kernel || kmodule))
249 return demangled;
250
251 demangled = bfd_demangle(NULL, elf_name, demangle_flags);
252 if (demangled == NULL)
253 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
254 else if (rust_is_mangled(demangled))
255 /*
256 * Input to Rust demangling is the BFD-demangled
257 * name which it Rust-demangles in place.
258 */
259 rust_demangle_sym(demangled);
260
261 return demangled;
262 }
263
264 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
265 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
266 idx < nr_entries; \
267 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
268
269 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
270 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
271 idx < nr_entries; \
272 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
273
274 /*
275 * We need to check if we have a .dynsym, so that we can handle the
276 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
277 * .dynsym or .symtab).
278 * And always look at the original dso, not at debuginfo packages, that
279 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
280 */
281 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
282 {
283 uint32_t nr_rel_entries, idx;
284 GElf_Sym sym;
285 u64 plt_offset, plt_header_size, plt_entry_size;
286 GElf_Shdr shdr_plt;
287 struct symbol *f;
288 GElf_Shdr shdr_rel_plt, shdr_dynsym;
289 Elf_Data *reldata, *syms, *symstrs;
290 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
291 size_t dynsym_idx;
292 GElf_Ehdr ehdr;
293 char sympltname[1024];
294 Elf *elf;
295 int nr = 0, symidx, err = 0;
296
297 if (!ss->dynsym)
298 return 0;
299
300 elf = ss->elf;
301 ehdr = ss->ehdr;
302
303 scn_dynsym = ss->dynsym;
304 shdr_dynsym = ss->dynshdr;
305 dynsym_idx = ss->dynsym_idx;
306
307 if (scn_dynsym == NULL)
308 goto out_elf_end;
309
310 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
311 ".rela.plt", NULL);
312 if (scn_plt_rel == NULL) {
313 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
314 ".rel.plt", NULL);
315 if (scn_plt_rel == NULL)
316 goto out_elf_end;
317 }
318
319 err = -1;
320
321 if (shdr_rel_plt.sh_link != dynsym_idx)
322 goto out_elf_end;
323
324 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
325 goto out_elf_end;
326
327 /*
328 * Fetch the relocation section to find the idxes to the GOT
329 * and the symbols in the .dynsym they refer to.
330 */
331 reldata = elf_getdata(scn_plt_rel, NULL);
332 if (reldata == NULL)
333 goto out_elf_end;
334
335 syms = elf_getdata(scn_dynsym, NULL);
336 if (syms == NULL)
337 goto out_elf_end;
338
339 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
340 if (scn_symstrs == NULL)
341 goto out_elf_end;
342
343 symstrs = elf_getdata(scn_symstrs, NULL);
344 if (symstrs == NULL)
345 goto out_elf_end;
346
347 if (symstrs->d_size == 0)
348 goto out_elf_end;
349
350 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
351 plt_offset = shdr_plt.sh_offset;
352 switch (ehdr.e_machine) {
353 case EM_ARM:
354 plt_header_size = 20;
355 plt_entry_size = 12;
356 break;
357
358 case EM_AARCH64:
359 plt_header_size = 32;
360 plt_entry_size = 16;
361 break;
362
363 case EM_SPARC:
364 plt_header_size = 48;
365 plt_entry_size = 12;
366 break;
367
368 case EM_SPARCV9:
369 plt_header_size = 128;
370 plt_entry_size = 32;
371 break;
372
373 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
374 plt_header_size = shdr_plt.sh_entsize;
375 plt_entry_size = shdr_plt.sh_entsize;
376 break;
377 }
378 plt_offset += plt_header_size;
379
380 if (shdr_rel_plt.sh_type == SHT_RELA) {
381 GElf_Rela pos_mem, *pos;
382
383 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
384 nr_rel_entries) {
385 const char *elf_name = NULL;
386 char *demangled = NULL;
387 symidx = GELF_R_SYM(pos->r_info);
388 gelf_getsym(syms, symidx, &sym);
389
390 elf_name = elf_sym__name(&sym, symstrs);
391 demangled = demangle_sym(dso, 0, elf_name);
392 if (demangled != NULL)
393 elf_name = demangled;
394 snprintf(sympltname, sizeof(sympltname),
395 "%s@plt", elf_name);
396 free(demangled);
397
398 f = symbol__new(plt_offset, plt_entry_size,
399 STB_GLOBAL, STT_FUNC, sympltname);
400 if (!f)
401 goto out_elf_end;
402
403 plt_offset += plt_entry_size;
404 symbols__insert(&dso->symbols, f);
405 ++nr;
406 }
407 } else if (shdr_rel_plt.sh_type == SHT_REL) {
408 GElf_Rel pos_mem, *pos;
409 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
410 nr_rel_entries) {
411 const char *elf_name = NULL;
412 char *demangled = NULL;
413 symidx = GELF_R_SYM(pos->r_info);
414 gelf_getsym(syms, symidx, &sym);
415
416 elf_name = elf_sym__name(&sym, symstrs);
417 demangled = demangle_sym(dso, 0, elf_name);
418 if (demangled != NULL)
419 elf_name = demangled;
420 snprintf(sympltname, sizeof(sympltname),
421 "%s@plt", elf_name);
422 free(demangled);
423
424 f = symbol__new(plt_offset, plt_entry_size,
425 STB_GLOBAL, STT_FUNC, sympltname);
426 if (!f)
427 goto out_elf_end;
428
429 plt_offset += plt_entry_size;
430 symbols__insert(&dso->symbols, f);
431 ++nr;
432 }
433 }
434
435 err = 0;
436 out_elf_end:
437 if (err == 0)
438 return nr;
439 pr_debug("%s: problems reading %s PLT info.\n",
440 __func__, dso->long_name);
441 return 0;
442 }
443
444 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
445 {
446 return demangle_sym(dso, kmodule, elf_name);
447 }
448
449 /*
450 * Align offset to 4 bytes as needed for note name and descriptor data.
451 */
452 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
453
454 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
455 {
456 int err = -1;
457 GElf_Ehdr ehdr;
458 GElf_Shdr shdr;
459 Elf_Data *data;
460 Elf_Scn *sec;
461 Elf_Kind ek;
462 void *ptr;
463
464 if (size < BUILD_ID_SIZE)
465 goto out;
466
467 ek = elf_kind(elf);
468 if (ek != ELF_K_ELF)
469 goto out;
470
471 if (gelf_getehdr(elf, &ehdr) == NULL) {
472 pr_err("%s: cannot get elf header.\n", __func__);
473 goto out;
474 }
475
476 /*
477 * Check following sections for notes:
478 * '.note.gnu.build-id'
479 * '.notes'
480 * '.note' (VDSO specific)
481 */
482 do {
483 sec = elf_section_by_name(elf, &ehdr, &shdr,
484 ".note.gnu.build-id", NULL);
485 if (sec)
486 break;
487
488 sec = elf_section_by_name(elf, &ehdr, &shdr,
489 ".notes", NULL);
490 if (sec)
491 break;
492
493 sec = elf_section_by_name(elf, &ehdr, &shdr,
494 ".note", NULL);
495 if (sec)
496 break;
497
498 return err;
499
500 } while (0);
501
502 data = elf_getdata(sec, NULL);
503 if (data == NULL)
504 goto out;
505
506 ptr = data->d_buf;
507 while (ptr < (data->d_buf + data->d_size)) {
508 GElf_Nhdr *nhdr = ptr;
509 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
510 descsz = NOTE_ALIGN(nhdr->n_descsz);
511 const char *name;
512
513 ptr += sizeof(*nhdr);
514 name = ptr;
515 ptr += namesz;
516 if (nhdr->n_type == NT_GNU_BUILD_ID &&
517 nhdr->n_namesz == sizeof("GNU")) {
518 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
519 size_t sz = min(size, descsz);
520 memcpy(bf, ptr, sz);
521 memset(bf + sz, 0, size - sz);
522 err = descsz;
523 break;
524 }
525 }
526 ptr += descsz;
527 }
528
529 out:
530 return err;
531 }
532
533 int filename__read_build_id(const char *filename, void *bf, size_t size)
534 {
535 int fd, err = -1;
536 Elf *elf;
537
538 if (size < BUILD_ID_SIZE)
539 goto out;
540
541 fd = open(filename, O_RDONLY);
542 if (fd < 0)
543 goto out;
544
545 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
546 if (elf == NULL) {
547 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
548 goto out_close;
549 }
550
551 err = elf_read_build_id(elf, bf, size);
552
553 elf_end(elf);
554 out_close:
555 close(fd);
556 out:
557 return err;
558 }
559
560 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
561 {
562 int fd, err = -1;
563
564 if (size < BUILD_ID_SIZE)
565 goto out;
566
567 fd = open(filename, O_RDONLY);
568 if (fd < 0)
569 goto out;
570
571 while (1) {
572 char bf[BUFSIZ];
573 GElf_Nhdr nhdr;
574 size_t namesz, descsz;
575
576 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
577 break;
578
579 namesz = NOTE_ALIGN(nhdr.n_namesz);
580 descsz = NOTE_ALIGN(nhdr.n_descsz);
581 if (nhdr.n_type == NT_GNU_BUILD_ID &&
582 nhdr.n_namesz == sizeof("GNU")) {
583 if (read(fd, bf, namesz) != (ssize_t)namesz)
584 break;
585 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
586 size_t sz = min(descsz, size);
587 if (read(fd, build_id, sz) == (ssize_t)sz) {
588 memset(build_id + sz, 0, size - sz);
589 err = 0;
590 break;
591 }
592 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
593 break;
594 } else {
595 int n = namesz + descsz;
596
597 if (n > (int)sizeof(bf)) {
598 n = sizeof(bf);
599 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
600 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
601 }
602 if (read(fd, bf, n) != n)
603 break;
604 }
605 }
606 close(fd);
607 out:
608 return err;
609 }
610
611 int filename__read_debuglink(const char *filename, char *debuglink,
612 size_t size)
613 {
614 int fd, err = -1;
615 Elf *elf;
616 GElf_Ehdr ehdr;
617 GElf_Shdr shdr;
618 Elf_Data *data;
619 Elf_Scn *sec;
620 Elf_Kind ek;
621
622 fd = open(filename, O_RDONLY);
623 if (fd < 0)
624 goto out;
625
626 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
627 if (elf == NULL) {
628 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
629 goto out_close;
630 }
631
632 ek = elf_kind(elf);
633 if (ek != ELF_K_ELF)
634 goto out_elf_end;
635
636 if (gelf_getehdr(elf, &ehdr) == NULL) {
637 pr_err("%s: cannot get elf header.\n", __func__);
638 goto out_elf_end;
639 }
640
641 sec = elf_section_by_name(elf, &ehdr, &shdr,
642 ".gnu_debuglink", NULL);
643 if (sec == NULL)
644 goto out_elf_end;
645
646 data = elf_getdata(sec, NULL);
647 if (data == NULL)
648 goto out_elf_end;
649
650 /* the start of this section is a zero-terminated string */
651 strncpy(debuglink, data->d_buf, size);
652
653 err = 0;
654
655 out_elf_end:
656 elf_end(elf);
657 out_close:
658 close(fd);
659 out:
660 return err;
661 }
662
663 static int dso__swap_init(struct dso *dso, unsigned char eidata)
664 {
665 static unsigned int const endian = 1;
666
667 dso->needs_swap = DSO_SWAP__NO;
668
669 switch (eidata) {
670 case ELFDATA2LSB:
671 /* We are big endian, DSO is little endian. */
672 if (*(unsigned char const *)&endian != 1)
673 dso->needs_swap = DSO_SWAP__YES;
674 break;
675
676 case ELFDATA2MSB:
677 /* We are little endian, DSO is big endian. */
678 if (*(unsigned char const *)&endian != 0)
679 dso->needs_swap = DSO_SWAP__YES;
680 break;
681
682 default:
683 pr_err("unrecognized DSO data encoding %d\n", eidata);
684 return -EINVAL;
685 }
686
687 return 0;
688 }
689
690 bool symsrc__possibly_runtime(struct symsrc *ss)
691 {
692 return ss->dynsym || ss->opdsec;
693 }
694
695 bool symsrc__has_symtab(struct symsrc *ss)
696 {
697 return ss->symtab != NULL;
698 }
699
700 void symsrc__destroy(struct symsrc *ss)
701 {
702 zfree(&ss->name);
703 elf_end(ss->elf);
704 close(ss->fd);
705 }
706
707 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
708 {
709 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
710 }
711
712 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
713 enum dso_binary_type type)
714 {
715 GElf_Ehdr ehdr;
716 Elf *elf;
717 int fd;
718
719 if (dso__needs_decompress(dso)) {
720 fd = dso__decompress_kmodule_fd(dso, name);
721 if (fd < 0)
722 return -1;
723
724 type = dso->symtab_type;
725 } else {
726 fd = open(name, O_RDONLY);
727 if (fd < 0) {
728 dso->load_errno = errno;
729 return -1;
730 }
731 }
732
733 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
734 if (elf == NULL) {
735 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
736 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
737 goto out_close;
738 }
739
740 if (gelf_getehdr(elf, &ehdr) == NULL) {
741 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
742 pr_debug("%s: cannot get elf header.\n", __func__);
743 goto out_elf_end;
744 }
745
746 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
747 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
748 goto out_elf_end;
749 }
750
751 /* Always reject images with a mismatched build-id: */
752 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
753 u8 build_id[BUILD_ID_SIZE];
754
755 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
756 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
757 goto out_elf_end;
758 }
759
760 if (!dso__build_id_equal(dso, build_id)) {
761 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
762 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
763 goto out_elf_end;
764 }
765 }
766
767 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
768
769 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
770 NULL);
771 if (ss->symshdr.sh_type != SHT_SYMTAB)
772 ss->symtab = NULL;
773
774 ss->dynsym_idx = 0;
775 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
776 &ss->dynsym_idx);
777 if (ss->dynshdr.sh_type != SHT_DYNSYM)
778 ss->dynsym = NULL;
779
780 ss->opdidx = 0;
781 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
782 &ss->opdidx);
783 if (ss->opdshdr.sh_type != SHT_PROGBITS)
784 ss->opdsec = NULL;
785
786 if (dso->kernel == DSO_TYPE_USER)
787 ss->adjust_symbols = true;
788 else
789 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
790
791 ss->name = strdup(name);
792 if (!ss->name) {
793 dso->load_errno = errno;
794 goto out_elf_end;
795 }
796
797 ss->elf = elf;
798 ss->fd = fd;
799 ss->ehdr = ehdr;
800 ss->type = type;
801
802 return 0;
803
804 out_elf_end:
805 elf_end(elf);
806 out_close:
807 close(fd);
808 return -1;
809 }
810
811 /**
812 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
813 * @kmap: kernel maps and relocation reference symbol
814 *
815 * This function returns %true if we are dealing with the kernel maps and the
816 * relocation reference symbol has not yet been found. Otherwise %false is
817 * returned.
818 */
819 static bool ref_reloc_sym_not_found(struct kmap *kmap)
820 {
821 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
822 !kmap->ref_reloc_sym->unrelocated_addr;
823 }
824
825 /**
826 * ref_reloc - kernel relocation offset.
827 * @kmap: kernel maps and relocation reference symbol
828 *
829 * This function returns the offset of kernel addresses as determined by using
830 * the relocation reference symbol i.e. if the kernel has not been relocated
831 * then the return value is zero.
832 */
833 static u64 ref_reloc(struct kmap *kmap)
834 {
835 if (kmap && kmap->ref_reloc_sym &&
836 kmap->ref_reloc_sym->unrelocated_addr)
837 return kmap->ref_reloc_sym->addr -
838 kmap->ref_reloc_sym->unrelocated_addr;
839 return 0;
840 }
841
842 void __weak arch__sym_update(struct symbol *s __maybe_unused,
843 GElf_Sym *sym __maybe_unused) { }
844
845 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
846 GElf_Sym *sym, GElf_Shdr *shdr,
847 struct maps *kmaps, struct kmap *kmap,
848 struct dso **curr_dsop, struct map **curr_mapp,
849 const char *section_name,
850 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
851 {
852 struct dso *curr_dso = *curr_dsop;
853 struct map *curr_map;
854 char dso_name[PATH_MAX];
855
856 /* Adjust symbol to map to file offset */
857 if (adjust_kernel_syms)
858 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
859
860 if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
861 return 0;
862
863 if (strcmp(section_name, ".text") == 0) {
864 /*
865 * The initial kernel mapping is based on
866 * kallsyms and identity maps. Overwrite it to
867 * map to the kernel dso.
868 */
869 if (*remap_kernel && dso->kernel) {
870 *remap_kernel = false;
871 map->start = shdr->sh_addr + ref_reloc(kmap);
872 map->end = map->start + shdr->sh_size;
873 map->pgoff = shdr->sh_offset;
874 map->map_ip = map__map_ip;
875 map->unmap_ip = map__unmap_ip;
876 /* Ensure maps are correctly ordered */
877 if (kmaps) {
878 map__get(map);
879 maps__remove(kmaps, map);
880 maps__insert(kmaps, map);
881 map__put(map);
882 }
883 }
884
885 /*
886 * The initial module mapping is based on
887 * /proc/modules mapped to offset zero.
888 * Overwrite it to map to the module dso.
889 */
890 if (*remap_kernel && kmodule) {
891 *remap_kernel = false;
892 map->pgoff = shdr->sh_offset;
893 }
894
895 *curr_mapp = map;
896 *curr_dsop = dso;
897 return 0;
898 }
899
900 if (!kmap)
901 return 0;
902
903 snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
904
905 curr_map = maps__find_by_name(kmaps, dso_name);
906 if (curr_map == NULL) {
907 u64 start = sym->st_value;
908
909 if (kmodule)
910 start += map->start + shdr->sh_offset;
911
912 curr_dso = dso__new(dso_name);
913 if (curr_dso == NULL)
914 return -1;
915 curr_dso->kernel = dso->kernel;
916 curr_dso->long_name = dso->long_name;
917 curr_dso->long_name_len = dso->long_name_len;
918 curr_map = map__new2(start, curr_dso);
919 dso__put(curr_dso);
920 if (curr_map == NULL)
921 return -1;
922
923 if (curr_dso->kernel)
924 map__kmap(curr_map)->kmaps = kmaps;
925
926 if (adjust_kernel_syms) {
927 curr_map->start = shdr->sh_addr + ref_reloc(kmap);
928 curr_map->end = curr_map->start + shdr->sh_size;
929 curr_map->pgoff = shdr->sh_offset;
930 } else {
931 curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
932 }
933 curr_dso->symtab_type = dso->symtab_type;
934 maps__insert(kmaps, curr_map);
935 /*
936 * Add it before we drop the referece to curr_map, i.e. while
937 * we still are sure to have a reference to this DSO via
938 * *curr_map->dso.
939 */
940 dsos__add(&kmaps->machine->dsos, curr_dso);
941 /* kmaps already got it */
942 map__put(curr_map);
943 dso__set_loaded(curr_dso);
944 *curr_mapp = curr_map;
945 *curr_dsop = curr_dso;
946 } else
947 *curr_dsop = curr_map->dso;
948
949 return 0;
950 }
951
952 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
953 struct symsrc *runtime_ss, int kmodule)
954 {
955 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
956 struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
957 struct map *curr_map = map;
958 struct dso *curr_dso = dso;
959 Elf_Data *symstrs, *secstrs;
960 uint32_t nr_syms;
961 int err = -1;
962 uint32_t idx;
963 GElf_Ehdr ehdr;
964 GElf_Shdr shdr;
965 GElf_Shdr tshdr;
966 Elf_Data *syms, *opddata = NULL;
967 GElf_Sym sym;
968 Elf_Scn *sec, *sec_strndx;
969 Elf *elf;
970 int nr = 0;
971 bool remap_kernel = false, adjust_kernel_syms = false;
972
973 if (kmap && !kmaps)
974 return -1;
975
976 dso->symtab_type = syms_ss->type;
977 dso->is_64_bit = syms_ss->is_64_bit;
978 dso->rel = syms_ss->ehdr.e_type == ET_REL;
979
980 /*
981 * Modules may already have symbols from kallsyms, but those symbols
982 * have the wrong values for the dso maps, so remove them.
983 */
984 if (kmodule && syms_ss->symtab)
985 symbols__delete(&dso->symbols);
986
987 if (!syms_ss->symtab) {
988 /*
989 * If the vmlinux is stripped, fail so we will fall back
990 * to using kallsyms. The vmlinux runtime symbols aren't
991 * of much use.
992 */
993 if (dso->kernel)
994 goto out_elf_end;
995
996 syms_ss->symtab = syms_ss->dynsym;
997 syms_ss->symshdr = syms_ss->dynshdr;
998 }
999
1000 elf = syms_ss->elf;
1001 ehdr = syms_ss->ehdr;
1002 sec = syms_ss->symtab;
1003 shdr = syms_ss->symshdr;
1004
1005 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1006 ".text", NULL))
1007 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1008
1009 if (runtime_ss->opdsec)
1010 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1011
1012 syms = elf_getdata(sec, NULL);
1013 if (syms == NULL)
1014 goto out_elf_end;
1015
1016 sec = elf_getscn(elf, shdr.sh_link);
1017 if (sec == NULL)
1018 goto out_elf_end;
1019
1020 symstrs = elf_getdata(sec, NULL);
1021 if (symstrs == NULL)
1022 goto out_elf_end;
1023
1024 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1025 if (sec_strndx == NULL)
1026 goto out_elf_end;
1027
1028 secstrs = elf_getdata(sec_strndx, NULL);
1029 if (secstrs == NULL)
1030 goto out_elf_end;
1031
1032 nr_syms = shdr.sh_size / shdr.sh_entsize;
1033
1034 memset(&sym, 0, sizeof(sym));
1035
1036 /*
1037 * The kernel relocation symbol is needed in advance in order to adjust
1038 * kernel maps correctly.
1039 */
1040 if (ref_reloc_sym_not_found(kmap)) {
1041 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1042 const char *elf_name = elf_sym__name(&sym, symstrs);
1043
1044 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1045 continue;
1046 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1047 map->reloc = kmap->ref_reloc_sym->addr -
1048 kmap->ref_reloc_sym->unrelocated_addr;
1049 break;
1050 }
1051 }
1052
1053 /*
1054 * Handle any relocation of vdso necessary because older kernels
1055 * attempted to prelink vdso to its virtual address.
1056 */
1057 if (dso__is_vdso(dso))
1058 map->reloc = map->start - dso->text_offset;
1059
1060 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1061 /*
1062 * Initial kernel and module mappings do not map to the dso.
1063 * Flag the fixups.
1064 */
1065 if (dso->kernel || kmodule) {
1066 remap_kernel = true;
1067 adjust_kernel_syms = dso->adjust_symbols;
1068 }
1069 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1070 struct symbol *f;
1071 const char *elf_name = elf_sym__name(&sym, symstrs);
1072 char *demangled = NULL;
1073 int is_label = elf_sym__is_label(&sym);
1074 const char *section_name;
1075 bool used_opd = false;
1076
1077 if (!is_label && !elf_sym__filter(&sym))
1078 continue;
1079
1080 /* Reject ARM ELF "mapping symbols": these aren't unique and
1081 * don't identify functions, so will confuse the profile
1082 * output: */
1083 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1084 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1085 && (elf_name[2] == '\0' || elf_name[2] == '.'))
1086 continue;
1087 }
1088
1089 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1090 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1091 u64 *opd = opddata->d_buf + offset;
1092 sym.st_value = DSO__SWAP(dso, u64, *opd);
1093 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1094 sym.st_value);
1095 used_opd = true;
1096 }
1097 /*
1098 * When loading symbols in a data mapping, ABS symbols (which
1099 * has a value of SHN_ABS in its st_shndx) failed at
1100 * elf_getscn(). And it marks the loading as a failure so
1101 * already loaded symbols cannot be fixed up.
1102 *
1103 * I'm not sure what should be done. Just ignore them for now.
1104 * - Namhyung Kim
1105 */
1106 if (sym.st_shndx == SHN_ABS)
1107 continue;
1108
1109 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1110 if (!sec)
1111 goto out_elf_end;
1112
1113 gelf_getshdr(sec, &shdr);
1114
1115 if (is_label && !elf_sec__filter(&shdr, secstrs))
1116 continue;
1117
1118 section_name = elf_sec__name(&shdr, secstrs);
1119
1120 /* On ARM, symbols for thumb functions have 1 added to
1121 * the symbol address as a flag - remove it */
1122 if ((ehdr.e_machine == EM_ARM) &&
1123 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1124 (sym.st_value & 1))
1125 --sym.st_value;
1126
1127 if (dso->kernel || kmodule) {
1128 if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1129 section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1130 goto out_elf_end;
1131 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1132 (!used_opd && syms_ss->adjust_symbols)) {
1133 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1134 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1135 (u64)sym.st_value, (u64)shdr.sh_addr,
1136 (u64)shdr.sh_offset);
1137 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1138 }
1139
1140 demangled = demangle_sym(dso, kmodule, elf_name);
1141 if (demangled != NULL)
1142 elf_name = demangled;
1143
1144 f = symbol__new(sym.st_value, sym.st_size,
1145 GELF_ST_BIND(sym.st_info),
1146 GELF_ST_TYPE(sym.st_info), elf_name);
1147 free(demangled);
1148 if (!f)
1149 goto out_elf_end;
1150
1151 arch__sym_update(f, &sym);
1152
1153 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1154 nr++;
1155 }
1156
1157 /*
1158 * For misannotated, zeroed, ASM function sizes.
1159 */
1160 if (nr > 0) {
1161 symbols__fixup_end(&dso->symbols);
1162 symbols__fixup_duplicate(&dso->symbols);
1163 if (kmap) {
1164 /*
1165 * We need to fixup this here too because we create new
1166 * maps here, for things like vsyscall sections.
1167 */
1168 maps__fixup_end(kmaps);
1169 }
1170 }
1171 err = nr;
1172 out_elf_end:
1173 return err;
1174 }
1175
1176 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1177 {
1178 GElf_Phdr phdr;
1179 size_t i, phdrnum;
1180 int err;
1181 u64 sz;
1182
1183 if (elf_getphdrnum(elf, &phdrnum))
1184 return -1;
1185
1186 for (i = 0; i < phdrnum; i++) {
1187 if (gelf_getphdr(elf, i, &phdr) == NULL)
1188 return -1;
1189 if (phdr.p_type != PT_LOAD)
1190 continue;
1191 if (exe) {
1192 if (!(phdr.p_flags & PF_X))
1193 continue;
1194 } else {
1195 if (!(phdr.p_flags & PF_R))
1196 continue;
1197 }
1198 sz = min(phdr.p_memsz, phdr.p_filesz);
1199 if (!sz)
1200 continue;
1201 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1202 if (err)
1203 return err;
1204 }
1205 return 0;
1206 }
1207
1208 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1209 bool *is_64_bit)
1210 {
1211 int err;
1212 Elf *elf;
1213
1214 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1215 if (elf == NULL)
1216 return -1;
1217
1218 if (is_64_bit)
1219 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1220
1221 err = elf_read_maps(elf, exe, mapfn, data);
1222
1223 elf_end(elf);
1224 return err;
1225 }
1226
1227 enum dso_type dso__type_fd(int fd)
1228 {
1229 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1230 GElf_Ehdr ehdr;
1231 Elf_Kind ek;
1232 Elf *elf;
1233
1234 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1235 if (elf == NULL)
1236 goto out;
1237
1238 ek = elf_kind(elf);
1239 if (ek != ELF_K_ELF)
1240 goto out_end;
1241
1242 if (gelf_getclass(elf) == ELFCLASS64) {
1243 dso_type = DSO__TYPE_64BIT;
1244 goto out_end;
1245 }
1246
1247 if (gelf_getehdr(elf, &ehdr) == NULL)
1248 goto out_end;
1249
1250 if (ehdr.e_machine == EM_X86_64)
1251 dso_type = DSO__TYPE_X32BIT;
1252 else
1253 dso_type = DSO__TYPE_32BIT;
1254 out_end:
1255 elf_end(elf);
1256 out:
1257 return dso_type;
1258 }
1259
1260 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1261 {
1262 ssize_t r;
1263 size_t n;
1264 int err = -1;
1265 char *buf = malloc(page_size);
1266
1267 if (buf == NULL)
1268 return -1;
1269
1270 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1271 goto out;
1272
1273 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1274 goto out;
1275
1276 while (len) {
1277 n = page_size;
1278 if (len < n)
1279 n = len;
1280 /* Use read because mmap won't work on proc files */
1281 r = read(from, buf, n);
1282 if (r < 0)
1283 goto out;
1284 if (!r)
1285 break;
1286 n = r;
1287 r = write(to, buf, n);
1288 if (r < 0)
1289 goto out;
1290 if ((size_t)r != n)
1291 goto out;
1292 len -= n;
1293 }
1294
1295 err = 0;
1296 out:
1297 free(buf);
1298 return err;
1299 }
1300
1301 struct kcore {
1302 int fd;
1303 int elfclass;
1304 Elf *elf;
1305 GElf_Ehdr ehdr;
1306 };
1307
1308 static int kcore__open(struct kcore *kcore, const char *filename)
1309 {
1310 GElf_Ehdr *ehdr;
1311
1312 kcore->fd = open(filename, O_RDONLY);
1313 if (kcore->fd == -1)
1314 return -1;
1315
1316 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1317 if (!kcore->elf)
1318 goto out_close;
1319
1320 kcore->elfclass = gelf_getclass(kcore->elf);
1321 if (kcore->elfclass == ELFCLASSNONE)
1322 goto out_end;
1323
1324 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1325 if (!ehdr)
1326 goto out_end;
1327
1328 return 0;
1329
1330 out_end:
1331 elf_end(kcore->elf);
1332 out_close:
1333 close(kcore->fd);
1334 return -1;
1335 }
1336
1337 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1338 bool temp)
1339 {
1340 kcore->elfclass = elfclass;
1341
1342 if (temp)
1343 kcore->fd = mkstemp(filename);
1344 else
1345 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1346 if (kcore->fd == -1)
1347 return -1;
1348
1349 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1350 if (!kcore->elf)
1351 goto out_close;
1352
1353 if (!gelf_newehdr(kcore->elf, elfclass))
1354 goto out_end;
1355
1356 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1357
1358 return 0;
1359
1360 out_end:
1361 elf_end(kcore->elf);
1362 out_close:
1363 close(kcore->fd);
1364 unlink(filename);
1365 return -1;
1366 }
1367
1368 static void kcore__close(struct kcore *kcore)
1369 {
1370 elf_end(kcore->elf);
1371 close(kcore->fd);
1372 }
1373
1374 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1375 {
1376 GElf_Ehdr *ehdr = &to->ehdr;
1377 GElf_Ehdr *kehdr = &from->ehdr;
1378
1379 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1380 ehdr->e_type = kehdr->e_type;
1381 ehdr->e_machine = kehdr->e_machine;
1382 ehdr->e_version = kehdr->e_version;
1383 ehdr->e_entry = 0;
1384 ehdr->e_shoff = 0;
1385 ehdr->e_flags = kehdr->e_flags;
1386 ehdr->e_phnum = count;
1387 ehdr->e_shentsize = 0;
1388 ehdr->e_shnum = 0;
1389 ehdr->e_shstrndx = 0;
1390
1391 if (from->elfclass == ELFCLASS32) {
1392 ehdr->e_phoff = sizeof(Elf32_Ehdr);
1393 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
1394 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1395 } else {
1396 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1397 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1398 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1399 }
1400
1401 if (!gelf_update_ehdr(to->elf, ehdr))
1402 return -1;
1403
1404 if (!gelf_newphdr(to->elf, count))
1405 return -1;
1406
1407 return 0;
1408 }
1409
1410 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1411 u64 addr, u64 len)
1412 {
1413 GElf_Phdr phdr = {
1414 .p_type = PT_LOAD,
1415 .p_flags = PF_R | PF_W | PF_X,
1416 .p_offset = offset,
1417 .p_vaddr = addr,
1418 .p_paddr = 0,
1419 .p_filesz = len,
1420 .p_memsz = len,
1421 .p_align = page_size,
1422 };
1423
1424 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1425 return -1;
1426
1427 return 0;
1428 }
1429
1430 static off_t kcore__write(struct kcore *kcore)
1431 {
1432 return elf_update(kcore->elf, ELF_C_WRITE);
1433 }
1434
1435 struct phdr_data {
1436 off_t offset;
1437 off_t rel;
1438 u64 addr;
1439 u64 len;
1440 struct list_head node;
1441 struct phdr_data *remaps;
1442 };
1443
1444 struct sym_data {
1445 u64 addr;
1446 struct list_head node;
1447 };
1448
1449 struct kcore_copy_info {
1450 u64 stext;
1451 u64 etext;
1452 u64 first_symbol;
1453 u64 last_symbol;
1454 u64 first_module;
1455 u64 last_module_symbol;
1456 size_t phnum;
1457 struct list_head phdrs;
1458 struct list_head syms;
1459 };
1460
1461 #define kcore_copy__for_each_phdr(k, p) \
1462 list_for_each_entry((p), &(k)->phdrs, node)
1463
1464 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1465 {
1466 struct phdr_data *p = zalloc(sizeof(*p));
1467
1468 if (p) {
1469 p->addr = addr;
1470 p->len = len;
1471 p->offset = offset;
1472 }
1473
1474 return p;
1475 }
1476
1477 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1478 u64 addr, u64 len,
1479 off_t offset)
1480 {
1481 struct phdr_data *p = phdr_data__new(addr, len, offset);
1482
1483 if (p)
1484 list_add_tail(&p->node, &kci->phdrs);
1485
1486 return p;
1487 }
1488
1489 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1490 {
1491 struct phdr_data *p, *tmp;
1492
1493 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1494 list_del_init(&p->node);
1495 free(p);
1496 }
1497 }
1498
1499 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1500 u64 addr)
1501 {
1502 struct sym_data *s = zalloc(sizeof(*s));
1503
1504 if (s) {
1505 s->addr = addr;
1506 list_add_tail(&s->node, &kci->syms);
1507 }
1508
1509 return s;
1510 }
1511
1512 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1513 {
1514 struct sym_data *s, *tmp;
1515
1516 list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1517 list_del_init(&s->node);
1518 free(s);
1519 }
1520 }
1521
1522 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1523 u64 start)
1524 {
1525 struct kcore_copy_info *kci = arg;
1526
1527 if (!kallsyms__is_function(type))
1528 return 0;
1529
1530 if (strchr(name, '[')) {
1531 if (start > kci->last_module_symbol)
1532 kci->last_module_symbol = start;
1533 return 0;
1534 }
1535
1536 if (!kci->first_symbol || start < kci->first_symbol)
1537 kci->first_symbol = start;
1538
1539 if (!kci->last_symbol || start > kci->last_symbol)
1540 kci->last_symbol = start;
1541
1542 if (!strcmp(name, "_stext")) {
1543 kci->stext = start;
1544 return 0;
1545 }
1546
1547 if (!strcmp(name, "_etext")) {
1548 kci->etext = start;
1549 return 0;
1550 }
1551
1552 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1553 return -1;
1554
1555 return 0;
1556 }
1557
1558 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1559 const char *dir)
1560 {
1561 char kallsyms_filename[PATH_MAX];
1562
1563 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1564
1565 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1566 return -1;
1567
1568 if (kallsyms__parse(kallsyms_filename, kci,
1569 kcore_copy__process_kallsyms) < 0)
1570 return -1;
1571
1572 return 0;
1573 }
1574
1575 static int kcore_copy__process_modules(void *arg,
1576 const char *name __maybe_unused,
1577 u64 start, u64 size __maybe_unused)
1578 {
1579 struct kcore_copy_info *kci = arg;
1580
1581 if (!kci->first_module || start < kci->first_module)
1582 kci->first_module = start;
1583
1584 return 0;
1585 }
1586
1587 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1588 const char *dir)
1589 {
1590 char modules_filename[PATH_MAX];
1591
1592 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1593
1594 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1595 return -1;
1596
1597 if (modules__parse(modules_filename, kci,
1598 kcore_copy__process_modules) < 0)
1599 return -1;
1600
1601 return 0;
1602 }
1603
1604 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1605 u64 pgoff, u64 s, u64 e)
1606 {
1607 u64 len, offset;
1608
1609 if (s < start || s >= end)
1610 return 0;
1611
1612 offset = (s - start) + pgoff;
1613 len = e < end ? e - s : end - s;
1614
1615 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1616 }
1617
1618 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1619 {
1620 struct kcore_copy_info *kci = data;
1621 u64 end = start + len;
1622 struct sym_data *sdat;
1623
1624 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1625 return -1;
1626
1627 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1628 kci->last_module_symbol))
1629 return -1;
1630
1631 list_for_each_entry(sdat, &kci->syms, node) {
1632 u64 s = round_down(sdat->addr, page_size);
1633
1634 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1635 return -1;
1636 }
1637
1638 return 0;
1639 }
1640
1641 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1642 {
1643 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1644 return -1;
1645
1646 return 0;
1647 }
1648
1649 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1650 {
1651 struct phdr_data *p, *k = NULL;
1652 u64 kend;
1653
1654 if (!kci->stext)
1655 return;
1656
1657 /* Find phdr that corresponds to the kernel map (contains stext) */
1658 kcore_copy__for_each_phdr(kci, p) {
1659 u64 pend = p->addr + p->len - 1;
1660
1661 if (p->addr <= kci->stext && pend >= kci->stext) {
1662 k = p;
1663 break;
1664 }
1665 }
1666
1667 if (!k)
1668 return;
1669
1670 kend = k->offset + k->len;
1671
1672 /* Find phdrs that remap the kernel */
1673 kcore_copy__for_each_phdr(kci, p) {
1674 u64 pend = p->offset + p->len;
1675
1676 if (p == k)
1677 continue;
1678
1679 if (p->offset >= k->offset && pend <= kend)
1680 p->remaps = k;
1681 }
1682 }
1683
1684 static void kcore_copy__layout(struct kcore_copy_info *kci)
1685 {
1686 struct phdr_data *p;
1687 off_t rel = 0;
1688
1689 kcore_copy__find_remaps(kci);
1690
1691 kcore_copy__for_each_phdr(kci, p) {
1692 if (!p->remaps) {
1693 p->rel = rel;
1694 rel += p->len;
1695 }
1696 kci->phnum += 1;
1697 }
1698
1699 kcore_copy__for_each_phdr(kci, p) {
1700 struct phdr_data *k = p->remaps;
1701
1702 if (k)
1703 p->rel = p->offset - k->offset + k->rel;
1704 }
1705 }
1706
1707 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1708 Elf *elf)
1709 {
1710 if (kcore_copy__parse_kallsyms(kci, dir))
1711 return -1;
1712
1713 if (kcore_copy__parse_modules(kci, dir))
1714 return -1;
1715
1716 if (kci->stext)
1717 kci->stext = round_down(kci->stext, page_size);
1718 else
1719 kci->stext = round_down(kci->first_symbol, page_size);
1720
1721 if (kci->etext) {
1722 kci->etext = round_up(kci->etext, page_size);
1723 } else if (kci->last_symbol) {
1724 kci->etext = round_up(kci->last_symbol, page_size);
1725 kci->etext += page_size;
1726 }
1727
1728 kci->first_module = round_down(kci->first_module, page_size);
1729
1730 if (kci->last_module_symbol) {
1731 kci->last_module_symbol = round_up(kci->last_module_symbol,
1732 page_size);
1733 kci->last_module_symbol += page_size;
1734 }
1735
1736 if (!kci->stext || !kci->etext)
1737 return -1;
1738
1739 if (kci->first_module && !kci->last_module_symbol)
1740 return -1;
1741
1742 if (kcore_copy__read_maps(kci, elf))
1743 return -1;
1744
1745 kcore_copy__layout(kci);
1746
1747 return 0;
1748 }
1749
1750 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1751 const char *name)
1752 {
1753 char from_filename[PATH_MAX];
1754 char to_filename[PATH_MAX];
1755
1756 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1757 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1758
1759 return copyfile_mode(from_filename, to_filename, 0400);
1760 }
1761
1762 static int kcore_copy__unlink(const char *dir, const char *name)
1763 {
1764 char filename[PATH_MAX];
1765
1766 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1767
1768 return unlink(filename);
1769 }
1770
1771 static int kcore_copy__compare_fds(int from, int to)
1772 {
1773 char *buf_from;
1774 char *buf_to;
1775 ssize_t ret;
1776 size_t len;
1777 int err = -1;
1778
1779 buf_from = malloc(page_size);
1780 buf_to = malloc(page_size);
1781 if (!buf_from || !buf_to)
1782 goto out;
1783
1784 while (1) {
1785 /* Use read because mmap won't work on proc files */
1786 ret = read(from, buf_from, page_size);
1787 if (ret < 0)
1788 goto out;
1789
1790 if (!ret)
1791 break;
1792
1793 len = ret;
1794
1795 if (readn(to, buf_to, len) != (int)len)
1796 goto out;
1797
1798 if (memcmp(buf_from, buf_to, len))
1799 goto out;
1800 }
1801
1802 err = 0;
1803 out:
1804 free(buf_to);
1805 free(buf_from);
1806 return err;
1807 }
1808
1809 static int kcore_copy__compare_files(const char *from_filename,
1810 const char *to_filename)
1811 {
1812 int from, to, err = -1;
1813
1814 from = open(from_filename, O_RDONLY);
1815 if (from < 0)
1816 return -1;
1817
1818 to = open(to_filename, O_RDONLY);
1819 if (to < 0)
1820 goto out_close_from;
1821
1822 err = kcore_copy__compare_fds(from, to);
1823
1824 close(to);
1825 out_close_from:
1826 close(from);
1827 return err;
1828 }
1829
1830 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1831 const char *name)
1832 {
1833 char from_filename[PATH_MAX];
1834 char to_filename[PATH_MAX];
1835
1836 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1837 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1838
1839 return kcore_copy__compare_files(from_filename, to_filename);
1840 }
1841
1842 /**
1843 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1844 * @from_dir: from directory
1845 * @to_dir: to directory
1846 *
1847 * This function copies kallsyms, modules and kcore files from one directory to
1848 * another. kallsyms and modules are copied entirely. Only code segments are
1849 * copied from kcore. It is assumed that two segments suffice: one for the
1850 * kernel proper and one for all the modules. The code segments are determined
1851 * from kallsyms and modules files. The kernel map starts at _stext or the
1852 * lowest function symbol, and ends at _etext or the highest function symbol.
1853 * The module map starts at the lowest module address and ends at the highest
1854 * module symbol. Start addresses are rounded down to the nearest page. End
1855 * addresses are rounded up to the nearest page. An extra page is added to the
1856 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1857 * symbol too. Because it contains only code sections, the resulting kcore is
1858 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1859 * is not the same for the kernel map and the modules map. That happens because
1860 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1861 * kallsyms and modules files are compared with their copies to check that
1862 * modules have not been loaded or unloaded while the copies were taking place.
1863 *
1864 * Return: %0 on success, %-1 on failure.
1865 */
1866 int kcore_copy(const char *from_dir, const char *to_dir)
1867 {
1868 struct kcore kcore;
1869 struct kcore extract;
1870 int idx = 0, err = -1;
1871 off_t offset, sz;
1872 struct kcore_copy_info kci = { .stext = 0, };
1873 char kcore_filename[PATH_MAX];
1874 char extract_filename[PATH_MAX];
1875 struct phdr_data *p;
1876
1877 INIT_LIST_HEAD(&kci.phdrs);
1878 INIT_LIST_HEAD(&kci.syms);
1879
1880 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1881 return -1;
1882
1883 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1884 goto out_unlink_kallsyms;
1885
1886 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1887 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1888
1889 if (kcore__open(&kcore, kcore_filename))
1890 goto out_unlink_modules;
1891
1892 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1893 goto out_kcore_close;
1894
1895 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1896 goto out_kcore_close;
1897
1898 if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1899 goto out_extract_close;
1900
1901 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1902 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1903 offset = round_up(offset, page_size);
1904
1905 kcore_copy__for_each_phdr(&kci, p) {
1906 off_t offs = p->rel + offset;
1907
1908 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1909 goto out_extract_close;
1910 }
1911
1912 sz = kcore__write(&extract);
1913 if (sz < 0 || sz > offset)
1914 goto out_extract_close;
1915
1916 kcore_copy__for_each_phdr(&kci, p) {
1917 off_t offs = p->rel + offset;
1918
1919 if (p->remaps)
1920 continue;
1921 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1922 goto out_extract_close;
1923 }
1924
1925 if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1926 goto out_extract_close;
1927
1928 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1929 goto out_extract_close;
1930
1931 err = 0;
1932
1933 out_extract_close:
1934 kcore__close(&extract);
1935 if (err)
1936 unlink(extract_filename);
1937 out_kcore_close:
1938 kcore__close(&kcore);
1939 out_unlink_modules:
1940 if (err)
1941 kcore_copy__unlink(to_dir, "modules");
1942 out_unlink_kallsyms:
1943 if (err)
1944 kcore_copy__unlink(to_dir, "kallsyms");
1945
1946 kcore_copy__free_phdrs(&kci);
1947 kcore_copy__free_syms(&kci);
1948
1949 return err;
1950 }
1951
1952 int kcore_extract__create(struct kcore_extract *kce)
1953 {
1954 struct kcore kcore;
1955 struct kcore extract;
1956 size_t count = 1;
1957 int idx = 0, err = -1;
1958 off_t offset = page_size, sz;
1959
1960 if (kcore__open(&kcore, kce->kcore_filename))
1961 return -1;
1962
1963 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1964 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1965 goto out_kcore_close;
1966
1967 if (kcore__copy_hdr(&kcore, &extract, count))
1968 goto out_extract_close;
1969
1970 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1971 goto out_extract_close;
1972
1973 sz = kcore__write(&extract);
1974 if (sz < 0 || sz > offset)
1975 goto out_extract_close;
1976
1977 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1978 goto out_extract_close;
1979
1980 err = 0;
1981
1982 out_extract_close:
1983 kcore__close(&extract);
1984 if (err)
1985 unlink(kce->extract_filename);
1986 out_kcore_close:
1987 kcore__close(&kcore);
1988
1989 return err;
1990 }
1991
1992 void kcore_extract__delete(struct kcore_extract *kce)
1993 {
1994 unlink(kce->extract_filename);
1995 }
1996
1997 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1998
1999 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2000 {
2001 if (!base_off)
2002 return;
2003
2004 if (tmp->bit32)
2005 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2006 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2007 tmp->addr.a32[SDT_NOTE_IDX_BASE];
2008 else
2009 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2010 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2011 tmp->addr.a64[SDT_NOTE_IDX_BASE];
2012 }
2013
2014 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2015 GElf_Addr base_off)
2016 {
2017 if (!base_off)
2018 return;
2019
2020 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2021 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2022 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2023 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2024 }
2025
2026 /**
2027 * populate_sdt_note : Parse raw data and identify SDT note
2028 * @elf: elf of the opened file
2029 * @data: raw data of a section with description offset applied
2030 * @len: note description size
2031 * @type: type of the note
2032 * @sdt_notes: List to add the SDT note
2033 *
2034 * Responsible for parsing the @data in section .note.stapsdt in @elf and
2035 * if its an SDT note, it appends to @sdt_notes list.
2036 */
2037 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2038 struct list_head *sdt_notes)
2039 {
2040 const char *provider, *name, *args;
2041 struct sdt_note *tmp = NULL;
2042 GElf_Ehdr ehdr;
2043 GElf_Shdr shdr;
2044 int ret = -EINVAL;
2045
2046 union {
2047 Elf64_Addr a64[NR_ADDR];
2048 Elf32_Addr a32[NR_ADDR];
2049 } buf;
2050
2051 Elf_Data dst = {
2052 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2053 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2054 .d_off = 0, .d_align = 0
2055 };
2056 Elf_Data src = {
2057 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2058 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2059 .d_align = 0
2060 };
2061
2062 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2063 if (!tmp) {
2064 ret = -ENOMEM;
2065 goto out_err;
2066 }
2067
2068 INIT_LIST_HEAD(&tmp->note_list);
2069
2070 if (len < dst.d_size + 3)
2071 goto out_free_note;
2072
2073 /* Translation from file representation to memory representation */
2074 if (gelf_xlatetom(*elf, &dst, &src,
2075 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2076 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2077 goto out_free_note;
2078 }
2079
2080 /* Populate the fields of sdt_note */
2081 provider = data + dst.d_size;
2082
2083 name = (const char *)memchr(provider, '\0', data + len - provider);
2084 if (name++ == NULL)
2085 goto out_free_note;
2086
2087 tmp->provider = strdup(provider);
2088 if (!tmp->provider) {
2089 ret = -ENOMEM;
2090 goto out_free_note;
2091 }
2092 tmp->name = strdup(name);
2093 if (!tmp->name) {
2094 ret = -ENOMEM;
2095 goto out_free_prov;
2096 }
2097
2098 args = memchr(name, '\0', data + len - name);
2099
2100 /*
2101 * There is no argument if:
2102 * - We reached the end of the note;
2103 * - There is not enough room to hold a potential string;
2104 * - The argument string is empty or just contains ':'.
2105 */
2106 if (args == NULL || data + len - args < 2 ||
2107 args[1] == ':' || args[1] == '\0')
2108 tmp->args = NULL;
2109 else {
2110 tmp->args = strdup(++args);
2111 if (!tmp->args) {
2112 ret = -ENOMEM;
2113 goto out_free_name;
2114 }
2115 }
2116
2117 if (gelf_getclass(*elf) == ELFCLASS32) {
2118 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2119 tmp->bit32 = true;
2120 } else {
2121 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2122 tmp->bit32 = false;
2123 }
2124
2125 if (!gelf_getehdr(*elf, &ehdr)) {
2126 pr_debug("%s : cannot get elf header.\n", __func__);
2127 ret = -EBADF;
2128 goto out_free_args;
2129 }
2130
2131 /* Adjust the prelink effect :
2132 * Find out the .stapsdt.base section.
2133 * This scn will help us to handle prelinking (if present).
2134 * Compare the retrieved file offset of the base section with the
2135 * base address in the description of the SDT note. If its different,
2136 * then accordingly, adjust the note location.
2137 */
2138 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2139 sdt_adjust_loc(tmp, shdr.sh_offset);
2140
2141 /* Adjust reference counter offset */
2142 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2143 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2144
2145 list_add_tail(&tmp->note_list, sdt_notes);
2146 return 0;
2147
2148 out_free_args:
2149 zfree(&tmp->args);
2150 out_free_name:
2151 zfree(&tmp->name);
2152 out_free_prov:
2153 zfree(&tmp->provider);
2154 out_free_note:
2155 free(tmp);
2156 out_err:
2157 return ret;
2158 }
2159
2160 /**
2161 * construct_sdt_notes_list : constructs a list of SDT notes
2162 * @elf : elf to look into
2163 * @sdt_notes : empty list_head
2164 *
2165 * Scans the sections in 'elf' for the section
2166 * .note.stapsdt. It, then calls populate_sdt_note to find
2167 * out the SDT events and populates the 'sdt_notes'.
2168 */
2169 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2170 {
2171 GElf_Ehdr ehdr;
2172 Elf_Scn *scn = NULL;
2173 Elf_Data *data;
2174 GElf_Shdr shdr;
2175 size_t shstrndx, next;
2176 GElf_Nhdr nhdr;
2177 size_t name_off, desc_off, offset;
2178 int ret = 0;
2179
2180 if (gelf_getehdr(elf, &ehdr) == NULL) {
2181 ret = -EBADF;
2182 goto out_ret;
2183 }
2184 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2185 ret = -EBADF;
2186 goto out_ret;
2187 }
2188
2189 /* Look for the required section */
2190 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2191 if (!scn) {
2192 ret = -ENOENT;
2193 goto out_ret;
2194 }
2195
2196 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2197 ret = -ENOENT;
2198 goto out_ret;
2199 }
2200
2201 data = elf_getdata(scn, NULL);
2202
2203 /* Get the SDT notes */
2204 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2205 &desc_off)) > 0; offset = next) {
2206 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2207 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2208 sizeof(SDT_NOTE_NAME))) {
2209 /* Check the type of the note */
2210 if (nhdr.n_type != SDT_NOTE_TYPE)
2211 goto out_ret;
2212
2213 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2214 nhdr.n_descsz, sdt_notes);
2215 if (ret < 0)
2216 goto out_ret;
2217 }
2218 }
2219 if (list_empty(sdt_notes))
2220 ret = -ENOENT;
2221
2222 out_ret:
2223 return ret;
2224 }
2225
2226 /**
2227 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2228 * @head : empty list_head
2229 * @target : file to find SDT notes from
2230 *
2231 * This opens the file, initializes
2232 * the ELF and then calls construct_sdt_notes_list.
2233 */
2234 int get_sdt_note_list(struct list_head *head, const char *target)
2235 {
2236 Elf *elf;
2237 int fd, ret;
2238
2239 fd = open(target, O_RDONLY);
2240 if (fd < 0)
2241 return -EBADF;
2242
2243 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2244 if (!elf) {
2245 ret = -EBADF;
2246 goto out_close;
2247 }
2248 ret = construct_sdt_notes_list(elf, head);
2249 elf_end(elf);
2250 out_close:
2251 close(fd);
2252 return ret;
2253 }
2254
2255 /**
2256 * cleanup_sdt_note_list : free the sdt notes' list
2257 * @sdt_notes: sdt notes' list
2258 *
2259 * Free up the SDT notes in @sdt_notes.
2260 * Returns the number of SDT notes free'd.
2261 */
2262 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2263 {
2264 struct sdt_note *tmp, *pos;
2265 int nr_free = 0;
2266
2267 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2268 list_del_init(&pos->note_list);
2269 zfree(&pos->name);
2270 zfree(&pos->provider);
2271 free(pos);
2272 nr_free++;
2273 }
2274 return nr_free;
2275 }
2276
2277 /**
2278 * sdt_notes__get_count: Counts the number of sdt events
2279 * @start: list_head to sdt_notes list
2280 *
2281 * Returns the number of SDT notes in a list
2282 */
2283 int sdt_notes__get_count(struct list_head *start)
2284 {
2285 struct sdt_note *sdt_ptr;
2286 int count = 0;
2287
2288 list_for_each_entry(sdt_ptr, start, note_list)
2289 count++;
2290 return count;
2291 }
2292 #endif
2293
2294 void symbol__elf_init(void)
2295 {
2296 elf_version(EV_CURRENT);
2297 }
Linux with added FPC-III support