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 "compress.h"
11 #include "dso.h"
12 #include "map.h"
13 #include "maps.h"
14 #include "symbol.h"
15 #include "symsrc.h"
16 #include "demangle-cxx.h"
17 #include "demangle-ocaml.h"
18 #include "demangle-java.h"
19 #include "demangle-rust.h"
20 #include "machine.h"
21 #include "vdso.h"
22 #include "debug.h"
23 #include "util/copyfile.h"
24 #include <linux/ctype.h>
25 #include <linux/kernel.h>
26 #include <linux/zalloc.h>
27 #include <linux/string.h>
28 #include <symbol/kallsyms.h>
29 #include <internal/lib.h>
30
31 #ifdef HAVE_LIBBFD_SUPPORT
32 #define PACKAGE 'perf'
33 #include <bfd.h>
34 #endif
35
36 #if defined(HAVE_LIBBFD_SUPPORT) || defined(HAVE_CPLUS_DEMANGLE_SUPPORT)
37 #ifndef DMGL_PARAMS
38 #define DMGL_PARAMS (1 << 0) /* Include function args */
39 #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
40 #endif
41 #endif
42
43 #ifndef EM_AARCH64
44 #define EM_AARCH64 183 /* ARM 64 bit */
45 #endif
46
47 #ifndef EM_LOONGARCH
48 #define EM_LOONGARCH 258
49 #endif
50
51 #ifndef ELF32_ST_VISIBILITY
52 #define ELF32_ST_VISIBILITY(o) ((o) & 0x03)
53 #endif
54
55 /* For ELF64 the definitions are the same. */
56 #ifndef ELF64_ST_VISIBILITY
57 #define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o)
58 #endif
59
60 /* How to extract information held in the st_other field. */
61 #ifndef GELF_ST_VISIBILITY
62 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
63 #endif
64
65 typedef Elf64_Nhdr GElf_Nhdr;
66
67
68 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
elf_getphdrnum(Elf * elf,size_t * dst)69 static int elf_getphdrnum(Elf *elf, size_t *dst)
70 {
71 GElf_Ehdr gehdr;
72 GElf_Ehdr *ehdr;
73
74 ehdr = gelf_getehdr(elf, &gehdr);
75 if (!ehdr)
76 return -1;
77
78 *dst = ehdr->e_phnum;
79
80 return 0;
81 }
82 #endif
83
84 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
elf_getshdrstrndx(Elf * elf __maybe_unused,size_t * dst __maybe_unused)85 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
86 {
87 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
88 return -1;
89 }
90 #endif
91
92 #ifndef NT_GNU_BUILD_ID
93 #define NT_GNU_BUILD_ID 3
94 #endif
95
96 /**
97 * elf_symtab__for_each_symbol - iterate thru all the symbols
98 *
99 * @syms: struct elf_symtab instance to iterate
100 * @idx: uint32_t idx
101 * @sym: GElf_Sym iterator
102 */
103 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
104 for (idx = 0, gelf_getsym(syms, idx, &sym);\
105 idx < nr_syms; \
106 idx++, gelf_getsym(syms, idx, &sym))
107
elf_sym__type(const GElf_Sym * sym)108 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
109 {
110 return GELF_ST_TYPE(sym->st_info);
111 }
112
elf_sym__visibility(const GElf_Sym * sym)113 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
114 {
115 return GELF_ST_VISIBILITY(sym->st_other);
116 }
117
118 #ifndef STT_GNU_IFUNC
119 #define STT_GNU_IFUNC 10
120 #endif
121
elf_sym__is_function(const GElf_Sym * sym)122 static inline int elf_sym__is_function(const GElf_Sym *sym)
123 {
124 return (elf_sym__type(sym) == STT_FUNC ||
125 elf_sym__type(sym) == STT_GNU_IFUNC) &&
126 sym->st_name != 0 &&
127 sym->st_shndx != SHN_UNDEF;
128 }
129
elf_sym__is_object(const GElf_Sym * sym)130 static inline bool elf_sym__is_object(const GElf_Sym *sym)
131 {
132 return elf_sym__type(sym) == STT_OBJECT &&
133 sym->st_name != 0 &&
134 sym->st_shndx != SHN_UNDEF;
135 }
136
elf_sym__is_label(const GElf_Sym * sym)137 static inline int elf_sym__is_label(const GElf_Sym *sym)
138 {
139 return elf_sym__type(sym) == STT_NOTYPE &&
140 sym->st_name != 0 &&
141 sym->st_shndx != SHN_UNDEF &&
142 sym->st_shndx != SHN_ABS &&
143 elf_sym__visibility(sym) != STV_HIDDEN &&
144 elf_sym__visibility(sym) != STV_INTERNAL;
145 }
146
elf_sym__filter(GElf_Sym * sym)147 static bool elf_sym__filter(GElf_Sym *sym)
148 {
149 return elf_sym__is_function(sym) || elf_sym__is_object(sym);
150 }
151
elf_sym__name(const GElf_Sym * sym,const Elf_Data * symstrs)152 static inline const char *elf_sym__name(const GElf_Sym *sym,
153 const Elf_Data *symstrs)
154 {
155 return symstrs->d_buf + sym->st_name;
156 }
157
elf_sec__name(const GElf_Shdr * shdr,const Elf_Data * secstrs)158 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
159 const Elf_Data *secstrs)
160 {
161 return secstrs->d_buf + shdr->sh_name;
162 }
163
elf_sec__is_text(const GElf_Shdr * shdr,const Elf_Data * secstrs)164 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
165 const Elf_Data *secstrs)
166 {
167 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
168 }
169
elf_sec__is_data(const GElf_Shdr * shdr,const Elf_Data * secstrs)170 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
171 const Elf_Data *secstrs)
172 {
173 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
174 }
175
elf_sec__filter(GElf_Shdr * shdr,Elf_Data * secstrs)176 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
177 {
178 return elf_sec__is_text(shdr, secstrs) ||
179 elf_sec__is_data(shdr, secstrs);
180 }
181
elf_addr_to_index(Elf * elf,GElf_Addr addr)182 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
183 {
184 Elf_Scn *sec = NULL;
185 GElf_Shdr shdr;
186 size_t cnt = 1;
187
188 while ((sec = elf_nextscn(elf, sec)) != NULL) {
189 gelf_getshdr(sec, &shdr);
190
191 if ((addr >= shdr.sh_addr) &&
192 (addr < (shdr.sh_addr + shdr.sh_size)))
193 return cnt;
194
195 ++cnt;
196 }
197
198 return -1;
199 }
200
elf_section_by_name(Elf * elf,GElf_Ehdr * ep,GElf_Shdr * shp,const char * name,size_t * idx)201 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
202 GElf_Shdr *shp, const char *name, size_t *idx)
203 {
204 Elf_Scn *sec = NULL;
205 size_t cnt = 1;
206
207 /* ELF is corrupted/truncated, avoid calling elf_strptr. */
208 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
209 return NULL;
210
211 while ((sec = elf_nextscn(elf, sec)) != NULL) {
212 char *str;
213
214 gelf_getshdr(sec, shp);
215 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
216 if (str && !strcmp(name, str)) {
217 if (idx)
218 *idx = cnt;
219 return sec;
220 }
221 ++cnt;
222 }
223
224 return NULL;
225 }
226
filename__has_section(const char * filename,const char * sec)227 bool filename__has_section(const char *filename, const char *sec)
228 {
229 int fd;
230 Elf *elf;
231 GElf_Ehdr ehdr;
232 GElf_Shdr shdr;
233 bool found = false;
234
235 fd = open(filename, O_RDONLY);
236 if (fd < 0)
237 return false;
238
239 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
240 if (elf == NULL)
241 goto out;
242
243 if (gelf_getehdr(elf, &ehdr) == NULL)
244 goto elf_out;
245
246 found = !!elf_section_by_name(elf, &ehdr, &shdr, sec, NULL);
247
248 elf_out:
249 elf_end(elf);
250 out:
251 close(fd);
252 return found;
253 }
254
elf_read_program_header(Elf * elf,u64 vaddr,GElf_Phdr * phdr)255 static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr)
256 {
257 size_t i, phdrnum;
258 u64 sz;
259
260 if (elf_getphdrnum(elf, &phdrnum))
261 return -1;
262
263 for (i = 0; i < phdrnum; i++) {
264 if (gelf_getphdr(elf, i, phdr) == NULL)
265 return -1;
266
267 if (phdr->p_type != PT_LOAD)
268 continue;
269
270 sz = max(phdr->p_memsz, phdr->p_filesz);
271 if (!sz)
272 continue;
273
274 if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz))
275 return 0;
276 }
277
278 /* Not found any valid program header */
279 return -1;
280 }
281
want_demangle(bool is_kernel_sym)282 static bool want_demangle(bool is_kernel_sym)
283 {
284 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
285 }
286
287 /*
288 * Demangle C++ function signature, typically replaced by demangle-cxx.cpp
289 * version.
290 */
291 #ifndef HAVE_CXA_DEMANGLE_SUPPORT
cxx_demangle_sym(const char * str __maybe_unused,bool params __maybe_unused,bool modifiers __maybe_unused)292 char *cxx_demangle_sym(const char *str __maybe_unused, bool params __maybe_unused,
293 bool modifiers __maybe_unused)
294 {
295 #ifdef HAVE_LIBBFD_SUPPORT
296 int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0);
297
298 return bfd_demangle(NULL, str, flags);
299 #elif defined(HAVE_CPLUS_DEMANGLE_SUPPORT)
300 int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0);
301
302 return cplus_demangle(str, flags);
303 #else
304 return NULL;
305 #endif
306 }
307 #endif /* !HAVE_CXA_DEMANGLE_SUPPORT */
308
demangle_sym(struct dso * dso,int kmodule,const char * elf_name)309 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
310 {
311 char *demangled = NULL;
312
313 /*
314 * We need to figure out if the object was created from C++ sources
315 * DWARF DW_compile_unit has this, but we don't always have access
316 * to it...
317 */
318 if (!want_demangle(dso__kernel(dso) || kmodule))
319 return demangled;
320
321 demangled = cxx_demangle_sym(elf_name, verbose > 0, verbose > 0);
322 if (demangled == NULL) {
323 demangled = ocaml_demangle_sym(elf_name);
324 if (demangled == NULL) {
325 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
326 }
327 }
328 else if (rust_is_mangled(demangled))
329 /*
330 * Input to Rust demangling is the BFD-demangled
331 * name which it Rust-demangles in place.
332 */
333 rust_demangle_sym(demangled);
334
335 return demangled;
336 }
337
338 struct rel_info {
339 u32 nr_entries;
340 u32 *sorted;
341 bool is_rela;
342 Elf_Data *reldata;
343 GElf_Rela rela;
344 GElf_Rel rel;
345 };
346
get_rel_symidx(struct rel_info * ri,u32 idx)347 static u32 get_rel_symidx(struct rel_info *ri, u32 idx)
348 {
349 idx = ri->sorted ? ri->sorted[idx] : idx;
350 if (ri->is_rela) {
351 gelf_getrela(ri->reldata, idx, &ri->rela);
352 return GELF_R_SYM(ri->rela.r_info);
353 }
354 gelf_getrel(ri->reldata, idx, &ri->rel);
355 return GELF_R_SYM(ri->rel.r_info);
356 }
357
get_rel_offset(struct rel_info * ri,u32 x)358 static u64 get_rel_offset(struct rel_info *ri, u32 x)
359 {
360 if (ri->is_rela) {
361 GElf_Rela rela;
362
363 gelf_getrela(ri->reldata, x, &rela);
364 return rela.r_offset;
365 } else {
366 GElf_Rel rel;
367
368 gelf_getrel(ri->reldata, x, &rel);
369 return rel.r_offset;
370 }
371 }
372
rel_cmp(const void * a,const void * b,void * r)373 static int rel_cmp(const void *a, const void *b, void *r)
374 {
375 struct rel_info *ri = r;
376 u64 a_offset = get_rel_offset(ri, *(const u32 *)a);
377 u64 b_offset = get_rel_offset(ri, *(const u32 *)b);
378
379 return a_offset < b_offset ? -1 : (a_offset > b_offset ? 1 : 0);
380 }
381
sort_rel(struct rel_info * ri)382 static int sort_rel(struct rel_info *ri)
383 {
384 size_t sz = sizeof(ri->sorted[0]);
385 u32 i;
386
387 ri->sorted = calloc(ri->nr_entries, sz);
388 if (!ri->sorted)
389 return -1;
390 for (i = 0; i < ri->nr_entries; i++)
391 ri->sorted[i] = i;
392 qsort_r(ri->sorted, ri->nr_entries, sz, rel_cmp, ri);
393 return 0;
394 }
395
396 /*
397 * For x86_64, the GNU linker is putting IFUNC information in the relocation
398 * addend.
399 */
addend_may_be_ifunc(GElf_Ehdr * ehdr,struct rel_info * ri)400 static bool addend_may_be_ifunc(GElf_Ehdr *ehdr, struct rel_info *ri)
401 {
402 return ehdr->e_machine == EM_X86_64 && ri->is_rela &&
403 GELF_R_TYPE(ri->rela.r_info) == R_X86_64_IRELATIVE;
404 }
405
get_ifunc_name(Elf * elf,struct dso * dso,GElf_Ehdr * ehdr,struct rel_info * ri,char * buf,size_t buf_sz)406 static bool get_ifunc_name(Elf *elf, struct dso *dso, GElf_Ehdr *ehdr,
407 struct rel_info *ri, char *buf, size_t buf_sz)
408 {
409 u64 addr = ri->rela.r_addend;
410 struct symbol *sym;
411 GElf_Phdr phdr;
412
413 if (!addend_may_be_ifunc(ehdr, ri))
414 return false;
415
416 if (elf_read_program_header(elf, addr, &phdr))
417 return false;
418
419 addr -= phdr.p_vaddr - phdr.p_offset;
420
421 sym = dso__find_symbol_nocache(dso, addr);
422
423 /* Expecting the address to be an IFUNC or IFUNC alias */
424 if (!sym || sym->start != addr || (sym->type != STT_GNU_IFUNC && !sym->ifunc_alias))
425 return false;
426
427 snprintf(buf, buf_sz, "%s@plt", sym->name);
428
429 return true;
430 }
431
exit_rel(struct rel_info * ri)432 static void exit_rel(struct rel_info *ri)
433 {
434 zfree(&ri->sorted);
435 }
436
get_plt_sizes(struct dso * dso,GElf_Ehdr * ehdr,GElf_Shdr * shdr_plt,u64 * plt_header_size,u64 * plt_entry_size)437 static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,
438 u64 *plt_header_size, u64 *plt_entry_size)
439 {
440 switch (ehdr->e_machine) {
441 case EM_ARM:
442 *plt_header_size = 20;
443 *plt_entry_size = 12;
444 return true;
445 case EM_AARCH64:
446 *plt_header_size = 32;
447 *plt_entry_size = 16;
448 return true;
449 case EM_LOONGARCH:
450 *plt_header_size = 32;
451 *plt_entry_size = 16;
452 return true;
453 case EM_SPARC:
454 *plt_header_size = 48;
455 *plt_entry_size = 12;
456 return true;
457 case EM_SPARCV9:
458 *plt_header_size = 128;
459 *plt_entry_size = 32;
460 return true;
461 case EM_386:
462 case EM_X86_64:
463 *plt_entry_size = shdr_plt->sh_entsize;
464 /* Size is 8 or 16, if not, assume alignment indicates size */
465 if (*plt_entry_size != 8 && *plt_entry_size != 16)
466 *plt_entry_size = shdr_plt->sh_addralign == 8 ? 8 : 16;
467 *plt_header_size = *plt_entry_size;
468 break;
469 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
470 *plt_header_size = shdr_plt->sh_entsize;
471 *plt_entry_size = shdr_plt->sh_entsize;
472 break;
473 }
474 if (*plt_entry_size)
475 return true;
476 pr_debug("Missing PLT entry size for %s\n", dso__long_name(dso));
477 return false;
478 }
479
machine_is_x86(GElf_Half e_machine)480 static bool machine_is_x86(GElf_Half e_machine)
481 {
482 return e_machine == EM_386 || e_machine == EM_X86_64;
483 }
484
485 struct rela_dyn {
486 GElf_Addr offset;
487 u32 sym_idx;
488 };
489
490 struct rela_dyn_info {
491 struct dso *dso;
492 Elf_Data *plt_got_data;
493 u32 nr_entries;
494 struct rela_dyn *sorted;
495 Elf_Data *dynsym_data;
496 Elf_Data *dynstr_data;
497 Elf_Data *rela_dyn_data;
498 };
499
exit_rela_dyn(struct rela_dyn_info * di)500 static void exit_rela_dyn(struct rela_dyn_info *di)
501 {
502 zfree(&di->sorted);
503 }
504
cmp_offset(const void * a,const void * b)505 static int cmp_offset(const void *a, const void *b)
506 {
507 const struct rela_dyn *va = a;
508 const struct rela_dyn *vb = b;
509
510 return va->offset < vb->offset ? -1 : (va->offset > vb->offset ? 1 : 0);
511 }
512
sort_rela_dyn(struct rela_dyn_info * di)513 static int sort_rela_dyn(struct rela_dyn_info *di)
514 {
515 u32 i, n;
516
517 di->sorted = calloc(di->nr_entries, sizeof(di->sorted[0]));
518 if (!di->sorted)
519 return -1;
520
521 /* Get data for sorting: the offset and symbol index */
522 for (i = 0, n = 0; i < di->nr_entries; i++) {
523 GElf_Rela rela;
524 u32 sym_idx;
525
526 gelf_getrela(di->rela_dyn_data, i, &rela);
527 sym_idx = GELF_R_SYM(rela.r_info);
528 if (sym_idx) {
529 di->sorted[n].sym_idx = sym_idx;
530 di->sorted[n].offset = rela.r_offset;
531 n += 1;
532 }
533 }
534
535 /* Sort by offset */
536 di->nr_entries = n;
537 qsort(di->sorted, n, sizeof(di->sorted[0]), cmp_offset);
538
539 return 0;
540 }
541
get_rela_dyn_info(Elf * elf,GElf_Ehdr * ehdr,struct rela_dyn_info * di,Elf_Scn * scn)542 static void get_rela_dyn_info(Elf *elf, GElf_Ehdr *ehdr, struct rela_dyn_info *di, Elf_Scn *scn)
543 {
544 GElf_Shdr rela_dyn_shdr;
545 GElf_Shdr shdr;
546
547 di->plt_got_data = elf_getdata(scn, NULL);
548
549 scn = elf_section_by_name(elf, ehdr, &rela_dyn_shdr, ".rela.dyn", NULL);
550 if (!scn || !rela_dyn_shdr.sh_link || !rela_dyn_shdr.sh_entsize)
551 return;
552
553 di->nr_entries = rela_dyn_shdr.sh_size / rela_dyn_shdr.sh_entsize;
554 di->rela_dyn_data = elf_getdata(scn, NULL);
555
556 scn = elf_getscn(elf, rela_dyn_shdr.sh_link);
557 if (!scn || !gelf_getshdr(scn, &shdr) || !shdr.sh_link)
558 return;
559
560 di->dynsym_data = elf_getdata(scn, NULL);
561 di->dynstr_data = elf_getdata(elf_getscn(elf, shdr.sh_link), NULL);
562
563 if (!di->plt_got_data || !di->dynstr_data || !di->dynsym_data || !di->rela_dyn_data)
564 return;
565
566 /* Sort into offset order */
567 sort_rela_dyn(di);
568 }
569
570 /* Get instruction displacement from a plt entry for x86_64 */
get_x86_64_plt_disp(const u8 * p)571 static u32 get_x86_64_plt_disp(const u8 *p)
572 {
573 u8 endbr64[] = {0xf3, 0x0f, 0x1e, 0xfa};
574 int n = 0;
575
576 /* Skip endbr64 */
577 if (!memcmp(p, endbr64, sizeof(endbr64)))
578 n += sizeof(endbr64);
579 /* Skip bnd prefix */
580 if (p[n] == 0xf2)
581 n += 1;
582 /* jmp with 4-byte displacement */
583 if (p[n] == 0xff && p[n + 1] == 0x25) {
584 u32 disp;
585
586 n += 2;
587 /* Also add offset from start of entry to end of instruction */
588 memcpy(&disp, p + n, sizeof(disp));
589 return n + 4 + le32toh(disp);
590 }
591 return 0;
592 }
593
get_plt_got_name(GElf_Shdr * shdr,size_t i,struct rela_dyn_info * di,char * buf,size_t buf_sz)594 static bool get_plt_got_name(GElf_Shdr *shdr, size_t i,
595 struct rela_dyn_info *di,
596 char *buf, size_t buf_sz)
597 {
598 struct rela_dyn vi, *vr;
599 const char *sym_name;
600 char *demangled;
601 GElf_Sym sym;
602 bool result;
603 u32 disp;
604
605 if (!di->sorted)
606 return false;
607
608 disp = get_x86_64_plt_disp(di->plt_got_data->d_buf + i);
609 if (!disp)
610 return false;
611
612 /* Compute target offset of the .plt.got entry */
613 vi.offset = shdr->sh_offset + di->plt_got_data->d_off + i + disp;
614
615 /* Find that offset in .rela.dyn (sorted by offset) */
616 vr = bsearch(&vi, di->sorted, di->nr_entries, sizeof(di->sorted[0]), cmp_offset);
617 if (!vr)
618 return false;
619
620 /* Get the associated symbol */
621 gelf_getsym(di->dynsym_data, vr->sym_idx, &sym);
622 sym_name = elf_sym__name(&sym, di->dynstr_data);
623 demangled = demangle_sym(di->dso, 0, sym_name);
624 if (demangled != NULL)
625 sym_name = demangled;
626
627 snprintf(buf, buf_sz, "%s@plt", sym_name);
628
629 result = *sym_name;
630
631 free(demangled);
632
633 return result;
634 }
635
dso__synthesize_plt_got_symbols(struct dso * dso,Elf * elf,GElf_Ehdr * ehdr,char * buf,size_t buf_sz)636 static int dso__synthesize_plt_got_symbols(struct dso *dso, Elf *elf,
637 GElf_Ehdr *ehdr,
638 char *buf, size_t buf_sz)
639 {
640 struct rela_dyn_info di = { .dso = dso };
641 struct symbol *sym;
642 GElf_Shdr shdr;
643 Elf_Scn *scn;
644 int err = -1;
645 size_t i;
646
647 scn = elf_section_by_name(elf, ehdr, &shdr, ".plt.got", NULL);
648 if (!scn || !shdr.sh_entsize)
649 return 0;
650
651 if (ehdr->e_machine == EM_X86_64)
652 get_rela_dyn_info(elf, ehdr, &di, scn);
653
654 for (i = 0; i < shdr.sh_size; i += shdr.sh_entsize) {
655 if (!get_plt_got_name(&shdr, i, &di, buf, buf_sz))
656 snprintf(buf, buf_sz, "offset_%#" PRIx64 "@plt", (u64)shdr.sh_offset + i);
657 sym = symbol__new(shdr.sh_offset + i, shdr.sh_entsize, STB_GLOBAL, STT_FUNC, buf);
658 if (!sym)
659 goto out;
660 symbols__insert(dso__symbols(dso), sym);
661 }
662 err = 0;
663 out:
664 exit_rela_dyn(&di);
665 return err;
666 }
667
668 /*
669 * We need to check if we have a .dynsym, so that we can handle the
670 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
671 * .dynsym or .symtab).
672 * And always look at the original dso, not at debuginfo packages, that
673 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
674 */
dso__synthesize_plt_symbols(struct dso * dso,struct symsrc * ss)675 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
676 {
677 uint32_t idx;
678 GElf_Sym sym;
679 u64 plt_offset, plt_header_size, plt_entry_size;
680 GElf_Shdr shdr_plt, plt_sec_shdr;
681 struct symbol *f, *plt_sym;
682 GElf_Shdr shdr_rel_plt, shdr_dynsym;
683 Elf_Data *syms, *symstrs;
684 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
685 GElf_Ehdr ehdr;
686 char sympltname[1024];
687 Elf *elf;
688 int nr = 0, err = -1;
689 struct rel_info ri = { .is_rela = false };
690 bool lazy_plt;
691
692 elf = ss->elf;
693 ehdr = ss->ehdr;
694
695 if (!elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL))
696 return 0;
697
698 /*
699 * A symbol from a previous section (e.g. .init) can have been expanded
700 * by symbols__fixup_end() to overlap .plt. Truncate it before adding
701 * a symbol for .plt header.
702 */
703 f = dso__find_symbol_nocache(dso, shdr_plt.sh_offset);
704 if (f && f->start < shdr_plt.sh_offset && f->end > shdr_plt.sh_offset)
705 f->end = shdr_plt.sh_offset;
706
707 if (!get_plt_sizes(dso, &ehdr, &shdr_plt, &plt_header_size, &plt_entry_size))
708 return 0;
709
710 /* Add a symbol for .plt header */
711 plt_sym = symbol__new(shdr_plt.sh_offset, plt_header_size, STB_GLOBAL, STT_FUNC, ".plt");
712 if (!plt_sym)
713 goto out_elf_end;
714 symbols__insert(dso__symbols(dso), plt_sym);
715
716 /* Only x86 has .plt.got */
717 if (machine_is_x86(ehdr.e_machine) &&
718 dso__synthesize_plt_got_symbols(dso, elf, &ehdr, sympltname, sizeof(sympltname)))
719 goto out_elf_end;
720
721 /* Only x86 has .plt.sec */
722 if (machine_is_x86(ehdr.e_machine) &&
723 elf_section_by_name(elf, &ehdr, &plt_sec_shdr, ".plt.sec", NULL)) {
724 if (!get_plt_sizes(dso, &ehdr, &plt_sec_shdr, &plt_header_size, &plt_entry_size))
725 return 0;
726 /* Extend .plt symbol to entire .plt */
727 plt_sym->end = plt_sym->start + shdr_plt.sh_size;
728 /* Use .plt.sec offset */
729 plt_offset = plt_sec_shdr.sh_offset;
730 lazy_plt = false;
731 } else {
732 plt_offset = shdr_plt.sh_offset;
733 lazy_plt = true;
734 }
735
736 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
737 ".rela.plt", NULL);
738 if (scn_plt_rel == NULL) {
739 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
740 ".rel.plt", NULL);
741 if (scn_plt_rel == NULL)
742 return 0;
743 }
744
745 if (shdr_rel_plt.sh_type != SHT_RELA &&
746 shdr_rel_plt.sh_type != SHT_REL)
747 return 0;
748
749 if (!shdr_rel_plt.sh_link)
750 return 0;
751
752 if (shdr_rel_plt.sh_link == ss->dynsym_idx) {
753 scn_dynsym = ss->dynsym;
754 shdr_dynsym = ss->dynshdr;
755 } else if (shdr_rel_plt.sh_link == ss->symtab_idx) {
756 /*
757 * A static executable can have a .plt due to IFUNCs, in which
758 * case .symtab is used not .dynsym.
759 */
760 scn_dynsym = ss->symtab;
761 shdr_dynsym = ss->symshdr;
762 } else {
763 goto out_elf_end;
764 }
765
766 if (!scn_dynsym)
767 return 0;
768
769 /*
770 * Fetch the relocation section to find the idxes to the GOT
771 * and the symbols in the .dynsym they refer to.
772 */
773 ri.reldata = elf_getdata(scn_plt_rel, NULL);
774 if (!ri.reldata)
775 goto out_elf_end;
776
777 syms = elf_getdata(scn_dynsym, NULL);
778 if (syms == NULL)
779 goto out_elf_end;
780
781 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
782 if (scn_symstrs == NULL)
783 goto out_elf_end;
784
785 symstrs = elf_getdata(scn_symstrs, NULL);
786 if (symstrs == NULL)
787 goto out_elf_end;
788
789 if (symstrs->d_size == 0)
790 goto out_elf_end;
791
792 ri.nr_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
793
794 ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA;
795
796 if (lazy_plt) {
797 /*
798 * Assume a .plt with the same number of entries as the number
799 * of relocation entries is not lazy and does not have a header.
800 */
801 if (ri.nr_entries * plt_entry_size == shdr_plt.sh_size)
802 dso__delete_symbol(dso, plt_sym);
803 else
804 plt_offset += plt_header_size;
805 }
806
807 /*
808 * x86 doesn't insert IFUNC relocations in .plt order, so sort to get
809 * back in order.
810 */
811 if (machine_is_x86(ehdr.e_machine) && sort_rel(&ri))
812 goto out_elf_end;
813
814 for (idx = 0; idx < ri.nr_entries; idx++) {
815 const char *elf_name = NULL;
816 char *demangled = NULL;
817
818 gelf_getsym(syms, get_rel_symidx(&ri, idx), &sym);
819
820 elf_name = elf_sym__name(&sym, symstrs);
821 demangled = demangle_sym(dso, 0, elf_name);
822 if (demangled)
823 elf_name = demangled;
824 if (*elf_name)
825 snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name);
826 else if (!get_ifunc_name(elf, dso, &ehdr, &ri, sympltname, sizeof(sympltname)))
827 snprintf(sympltname, sizeof(sympltname),
828 "offset_%#" PRIx64 "@plt", plt_offset);
829 free(demangled);
830
831 f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname);
832 if (!f)
833 goto out_elf_end;
834
835 plt_offset += plt_entry_size;
836 symbols__insert(dso__symbols(dso), f);
837 ++nr;
838 }
839
840 err = 0;
841 out_elf_end:
842 exit_rel(&ri);
843 if (err == 0)
844 return nr;
845 pr_debug("%s: problems reading %s PLT info.\n",
846 __func__, dso__long_name(dso));
847 return 0;
848 }
849
dso__demangle_sym(struct dso * dso,int kmodule,const char * elf_name)850 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
851 {
852 return demangle_sym(dso, kmodule, elf_name);
853 }
854
855 /*
856 * Align offset to 4 bytes as needed for note name and descriptor data.
857 */
858 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
859
elf_read_build_id(Elf * elf,void * bf,size_t size)860 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
861 {
862 int err = -1;
863 GElf_Ehdr ehdr;
864 GElf_Shdr shdr;
865 Elf_Data *data;
866 Elf_Scn *sec;
867 Elf_Kind ek;
868 void *ptr;
869
870 if (size < BUILD_ID_SIZE)
871 goto out;
872
873 ek = elf_kind(elf);
874 if (ek != ELF_K_ELF)
875 goto out;
876
877 if (gelf_getehdr(elf, &ehdr) == NULL) {
878 pr_err("%s: cannot get elf header.\n", __func__);
879 goto out;
880 }
881
882 /*
883 * Check following sections for notes:
884 * '.note.gnu.build-id'
885 * '.notes'
886 * '.note' (VDSO specific)
887 */
888 do {
889 sec = elf_section_by_name(elf, &ehdr, &shdr,
890 ".note.gnu.build-id", NULL);
891 if (sec)
892 break;
893
894 sec = elf_section_by_name(elf, &ehdr, &shdr,
895 ".notes", NULL);
896 if (sec)
897 break;
898
899 sec = elf_section_by_name(elf, &ehdr, &shdr,
900 ".note", NULL);
901 if (sec)
902 break;
903
904 return err;
905
906 } while (0);
907
908 data = elf_getdata(sec, NULL);
909 if (data == NULL)
910 goto out;
911
912 ptr = data->d_buf;
913 while (ptr < (data->d_buf + data->d_size)) {
914 GElf_Nhdr *nhdr = ptr;
915 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
916 descsz = NOTE_ALIGN(nhdr->n_descsz);
917 const char *name;
918
919 ptr += sizeof(*nhdr);
920 name = ptr;
921 ptr += namesz;
922 if (nhdr->n_type == NT_GNU_BUILD_ID &&
923 nhdr->n_namesz == sizeof("GNU")) {
924 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
925 size_t sz = min(size, descsz);
926 memcpy(bf, ptr, sz);
927 memset(bf + sz, 0, size - sz);
928 err = sz;
929 break;
930 }
931 }
932 ptr += descsz;
933 }
934
935 out:
936 return err;
937 }
938
939 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT
940
read_build_id(const char * filename,struct build_id * bid)941 static int read_build_id(const char *filename, struct build_id *bid)
942 {
943 size_t size = sizeof(bid->data);
944 int err = -1;
945 bfd *abfd;
946
947 abfd = bfd_openr(filename, NULL);
948 if (!abfd)
949 return -1;
950
951 if (!bfd_check_format(abfd, bfd_object)) {
952 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
953 goto out_close;
954 }
955
956 if (!abfd->build_id || abfd->build_id->size > size)
957 goto out_close;
958
959 memcpy(bid->data, abfd->build_id->data, abfd->build_id->size);
960 memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size);
961 err = bid->size = abfd->build_id->size;
962
963 out_close:
964 bfd_close(abfd);
965 return err;
966 }
967
968 #else // HAVE_LIBBFD_BUILDID_SUPPORT
969
read_build_id(const char * filename,struct build_id * bid)970 static int read_build_id(const char *filename, struct build_id *bid)
971 {
972 size_t size = sizeof(bid->data);
973 int fd, err = -1;
974 Elf *elf;
975
976 if (size < BUILD_ID_SIZE)
977 goto out;
978
979 fd = open(filename, O_RDONLY);
980 if (fd < 0)
981 goto out;
982
983 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
984 if (elf == NULL) {
985 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
986 goto out_close;
987 }
988
989 err = elf_read_build_id(elf, bid->data, size);
990 if (err > 0)
991 bid->size = err;
992
993 elf_end(elf);
994 out_close:
995 close(fd);
996 out:
997 return err;
998 }
999
1000 #endif // HAVE_LIBBFD_BUILDID_SUPPORT
1001
filename__read_build_id(const char * filename,struct build_id * bid)1002 int filename__read_build_id(const char *filename, struct build_id *bid)
1003 {
1004 struct kmod_path m = { .name = NULL, };
1005 char path[PATH_MAX];
1006 int err;
1007
1008 if (!filename)
1009 return -EFAULT;
1010
1011 err = kmod_path__parse(&m, filename);
1012 if (err)
1013 return -1;
1014
1015 if (m.comp) {
1016 int error = 0, fd;
1017
1018 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
1019 if (fd < 0) {
1020 pr_debug("Failed to decompress (error %d) %s\n",
1021 error, filename);
1022 return -1;
1023 }
1024 close(fd);
1025 filename = path;
1026 }
1027
1028 err = read_build_id(filename, bid);
1029
1030 if (m.comp)
1031 unlink(filename);
1032 return err;
1033 }
1034
sysfs__read_build_id(const char * filename,struct build_id * bid)1035 int sysfs__read_build_id(const char *filename, struct build_id *bid)
1036 {
1037 size_t size = sizeof(bid->data);
1038 int fd, err = -1;
1039
1040 fd = open(filename, O_RDONLY);
1041 if (fd < 0)
1042 goto out;
1043
1044 while (1) {
1045 char bf[BUFSIZ];
1046 GElf_Nhdr nhdr;
1047 size_t namesz, descsz;
1048
1049 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
1050 break;
1051
1052 namesz = NOTE_ALIGN(nhdr.n_namesz);
1053 descsz = NOTE_ALIGN(nhdr.n_descsz);
1054 if (nhdr.n_type == NT_GNU_BUILD_ID &&
1055 nhdr.n_namesz == sizeof("GNU")) {
1056 if (read(fd, bf, namesz) != (ssize_t)namesz)
1057 break;
1058 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
1059 size_t sz = min(descsz, size);
1060 if (read(fd, bid->data, sz) == (ssize_t)sz) {
1061 memset(bid->data + sz, 0, size - sz);
1062 bid->size = sz;
1063 err = 0;
1064 break;
1065 }
1066 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
1067 break;
1068 } else {
1069 int n = namesz + descsz;
1070
1071 if (n > (int)sizeof(bf)) {
1072 n = sizeof(bf);
1073 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
1074 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
1075 }
1076 if (read(fd, bf, n) != n)
1077 break;
1078 }
1079 }
1080 close(fd);
1081 out:
1082 return err;
1083 }
1084
1085 #ifdef HAVE_LIBBFD_SUPPORT
1086
filename__read_debuglink(const char * filename,char * debuglink,size_t size)1087 int filename__read_debuglink(const char *filename, char *debuglink,
1088 size_t size)
1089 {
1090 int err = -1;
1091 asection *section;
1092 bfd *abfd;
1093
1094 abfd = bfd_openr(filename, NULL);
1095 if (!abfd)
1096 return -1;
1097
1098 if (!bfd_check_format(abfd, bfd_object)) {
1099 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
1100 goto out_close;
1101 }
1102
1103 section = bfd_get_section_by_name(abfd, ".gnu_debuglink");
1104 if (!section)
1105 goto out_close;
1106
1107 if (section->size > size)
1108 goto out_close;
1109
1110 if (!bfd_get_section_contents(abfd, section, debuglink, 0,
1111 section->size))
1112 goto out_close;
1113
1114 err = 0;
1115
1116 out_close:
1117 bfd_close(abfd);
1118 return err;
1119 }
1120
1121 #else
1122
filename__read_debuglink(const char * filename,char * debuglink,size_t size)1123 int filename__read_debuglink(const char *filename, char *debuglink,
1124 size_t size)
1125 {
1126 int fd, err = -1;
1127 Elf *elf;
1128 GElf_Ehdr ehdr;
1129 GElf_Shdr shdr;
1130 Elf_Data *data;
1131 Elf_Scn *sec;
1132 Elf_Kind ek;
1133
1134 fd = open(filename, O_RDONLY);
1135 if (fd < 0)
1136 goto out;
1137
1138 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1139 if (elf == NULL) {
1140 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
1141 goto out_close;
1142 }
1143
1144 ek = elf_kind(elf);
1145 if (ek != ELF_K_ELF)
1146 goto out_elf_end;
1147
1148 if (gelf_getehdr(elf, &ehdr) == NULL) {
1149 pr_err("%s: cannot get elf header.\n", __func__);
1150 goto out_elf_end;
1151 }
1152
1153 sec = elf_section_by_name(elf, &ehdr, &shdr,
1154 ".gnu_debuglink", NULL);
1155 if (sec == NULL)
1156 goto out_elf_end;
1157
1158 data = elf_getdata(sec, NULL);
1159 if (data == NULL)
1160 goto out_elf_end;
1161
1162 /* the start of this section is a zero-terminated string */
1163 strncpy(debuglink, data->d_buf, size);
1164
1165 err = 0;
1166
1167 out_elf_end:
1168 elf_end(elf);
1169 out_close:
1170 close(fd);
1171 out:
1172 return err;
1173 }
1174
1175 #endif
1176
symsrc__possibly_runtime(struct symsrc * ss)1177 bool symsrc__possibly_runtime(struct symsrc *ss)
1178 {
1179 return ss->dynsym || ss->opdsec;
1180 }
1181
symsrc__has_symtab(struct symsrc * ss)1182 bool symsrc__has_symtab(struct symsrc *ss)
1183 {
1184 return ss->symtab != NULL;
1185 }
1186
symsrc__destroy(struct symsrc * ss)1187 void symsrc__destroy(struct symsrc *ss)
1188 {
1189 zfree(&ss->name);
1190 elf_end(ss->elf);
1191 close(ss->fd);
1192 }
1193
elf__needs_adjust_symbols(GElf_Ehdr ehdr)1194 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
1195 {
1196 /*
1197 * Usually vmlinux is an ELF file with type ET_EXEC for most
1198 * architectures; except Arm64 kernel is linked with option
1199 * '-share', so need to check type ET_DYN.
1200 */
1201 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
1202 ehdr.e_type == ET_DYN;
1203 }
1204
read_gnu_debugdata(struct dso * dso,Elf * elf,const char * name,int * fd_ret)1205 static Elf *read_gnu_debugdata(struct dso *dso, Elf *elf, const char *name, int *fd_ret)
1206 {
1207 Elf *elf_embedded;
1208 GElf_Ehdr ehdr;
1209 GElf_Shdr shdr;
1210 Elf_Scn *scn;
1211 Elf_Data *scn_data;
1212 FILE *wrapped;
1213 size_t shndx;
1214 char temp_filename[] = "/tmp/perf.gnu_debugdata.elf.XXXXXX";
1215 int ret, temp_fd;
1216
1217 if (gelf_getehdr(elf, &ehdr) == NULL) {
1218 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
1219 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
1220 return NULL;
1221 }
1222
1223 scn = elf_section_by_name(elf, &ehdr, &shdr, ".gnu_debugdata", &shndx);
1224 if (!scn) {
1225 *dso__load_errno(dso) = -ENOENT;
1226 return NULL;
1227 }
1228
1229 if (shdr.sh_type == SHT_NOBITS) {
1230 pr_debug("%s: .gnu_debugdata of ELF file %s has no data.\n", __func__, name);
1231 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
1232 return NULL;
1233 }
1234
1235 scn_data = elf_rawdata(scn, NULL);
1236 if (!scn_data) {
1237 pr_debug("%s: error reading .gnu_debugdata of %s: %s\n", __func__,
1238 name, elf_errmsg(-1));
1239 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
1240 return NULL;
1241 }
1242
1243 wrapped = fmemopen(scn_data->d_buf, scn_data->d_size, "r");
1244 if (!wrapped) {
1245 pr_debug("%s: fmemopen: %s\n", __func__, strerror(errno));
1246 *dso__load_errno(dso) = -errno;
1247 return NULL;
1248 }
1249
1250 temp_fd = mkstemp(temp_filename);
1251 if (temp_fd < 0) {
1252 pr_debug("%s: mkstemp: %s\n", __func__, strerror(errno));
1253 *dso__load_errno(dso) = -errno;
1254 fclose(wrapped);
1255 return NULL;
1256 }
1257 unlink(temp_filename);
1258
1259 ret = lzma_decompress_stream_to_file(wrapped, temp_fd);
1260 fclose(wrapped);
1261 if (ret < 0) {
1262 *dso__load_errno(dso) = -errno;
1263 close(temp_fd);
1264 return NULL;
1265 }
1266
1267 elf_embedded = elf_begin(temp_fd, PERF_ELF_C_READ_MMAP, NULL);
1268 if (!elf_embedded) {
1269 pr_debug("%s: error reading .gnu_debugdata of %s: %s\n", __func__,
1270 name, elf_errmsg(-1));
1271 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
1272 close(temp_fd);
1273 return NULL;
1274 }
1275 pr_debug("%s: using .gnu_debugdata of %s\n", __func__, name);
1276 *fd_ret = temp_fd;
1277 return elf_embedded;
1278 }
1279
symsrc__init(struct symsrc * ss,struct dso * dso,const char * name,enum dso_binary_type type)1280 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
1281 enum dso_binary_type type)
1282 {
1283 GElf_Ehdr ehdr;
1284 Elf *elf;
1285 int fd;
1286
1287 if (dso__needs_decompress(dso)) {
1288 fd = dso__decompress_kmodule_fd(dso, name);
1289 if (fd < 0)
1290 return -1;
1291
1292 type = dso__symtab_type(dso);
1293 } else {
1294 fd = open(name, O_RDONLY);
1295 if (fd < 0) {
1296 *dso__load_errno(dso) = errno;
1297 return -1;
1298 }
1299 }
1300
1301 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1302 if (elf == NULL) {
1303 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
1304 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
1305 goto out_close;
1306 }
1307
1308 if (type == DSO_BINARY_TYPE__GNU_DEBUGDATA) {
1309 int new_fd;
1310 Elf *embedded = read_gnu_debugdata(dso, elf, name, &new_fd);
1311
1312 if (!embedded)
1313 goto out_close;
1314
1315 elf_end(elf);
1316 close(fd);
1317 fd = new_fd;
1318 elf = embedded;
1319 }
1320
1321 if (gelf_getehdr(elf, &ehdr) == NULL) {
1322 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
1323 pr_debug("%s: cannot get elf header.\n", __func__);
1324 goto out_elf_end;
1325 }
1326
1327 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
1328 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INTERNAL_ERROR;
1329 goto out_elf_end;
1330 }
1331
1332 /* Always reject images with a mismatched build-id: */
1333 if (dso__has_build_id(dso) && !symbol_conf.ignore_vmlinux_buildid) {
1334 u8 build_id[BUILD_ID_SIZE];
1335 struct build_id bid;
1336 int size;
1337
1338 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);
1339 if (size <= 0) {
1340 *dso__load_errno(dso) = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
1341 goto out_elf_end;
1342 }
1343
1344 build_id__init(&bid, build_id, size);
1345 if (!dso__build_id_equal(dso, &bid)) {
1346 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
1347 *dso__load_errno(dso) = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
1348 goto out_elf_end;
1349 }
1350 }
1351
1352 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1353
1354 ss->symtab_idx = 0;
1355 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
1356 &ss->symtab_idx);
1357 if (ss->symshdr.sh_type != SHT_SYMTAB)
1358 ss->symtab = NULL;
1359
1360 ss->dynsym_idx = 0;
1361 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
1362 &ss->dynsym_idx);
1363 if (ss->dynshdr.sh_type != SHT_DYNSYM)
1364 ss->dynsym = NULL;
1365
1366 ss->opdidx = 0;
1367 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
1368 &ss->opdidx);
1369 if (ss->opdshdr.sh_type != SHT_PROGBITS)
1370 ss->opdsec = NULL;
1371
1372 if (dso__kernel(dso) == DSO_SPACE__USER)
1373 ss->adjust_symbols = true;
1374 else
1375 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
1376
1377 ss->name = strdup(name);
1378 if (!ss->name) {
1379 *dso__load_errno(dso) = errno;
1380 goto out_elf_end;
1381 }
1382
1383 ss->elf = elf;
1384 ss->fd = fd;
1385 ss->ehdr = ehdr;
1386 ss->type = type;
1387
1388 return 0;
1389
1390 out_elf_end:
1391 elf_end(elf);
1392 out_close:
1393 close(fd);
1394 return -1;
1395 }
1396
is_exe_text(int flags)1397 static bool is_exe_text(int flags)
1398 {
1399 return (flags & (SHF_ALLOC | SHF_EXECINSTR)) == (SHF_ALLOC | SHF_EXECINSTR);
1400 }
1401
1402 /*
1403 * Some executable module sections like .noinstr.text might be laid out with
1404 * .text so they can use the same mapping (memory address to file offset).
1405 * Check if that is the case. Refer to kernel layout_sections(). Return the
1406 * maximum offset.
1407 */
max_text_section(Elf * elf,GElf_Ehdr * ehdr)1408 static u64 max_text_section(Elf *elf, GElf_Ehdr *ehdr)
1409 {
1410 Elf_Scn *sec = NULL;
1411 GElf_Shdr shdr;
1412 u64 offs = 0;
1413
1414 /* Doesn't work for some arch */
1415 if (ehdr->e_machine == EM_PARISC ||
1416 ehdr->e_machine == EM_ALPHA)
1417 return 0;
1418
1419 /* ELF is corrupted/truncated, avoid calling elf_strptr. */
1420 if (!elf_rawdata(elf_getscn(elf, ehdr->e_shstrndx), NULL))
1421 return 0;
1422
1423 while ((sec = elf_nextscn(elf, sec)) != NULL) {
1424 char *sec_name;
1425
1426 if (!gelf_getshdr(sec, &shdr))
1427 break;
1428
1429 if (!is_exe_text(shdr.sh_flags))
1430 continue;
1431
1432 /* .init and .exit sections are not placed with .text */
1433 sec_name = elf_strptr(elf, ehdr->e_shstrndx, shdr.sh_name);
1434 if (!sec_name ||
1435 strstarts(sec_name, ".init") ||
1436 strstarts(sec_name, ".exit"))
1437 break;
1438
1439 /* Must be next to previous, assumes .text is first */
1440 if (offs && PERF_ALIGN(offs, shdr.sh_addralign ?: 1) != shdr.sh_offset)
1441 break;
1442
1443 offs = shdr.sh_offset + shdr.sh_size;
1444 }
1445
1446 return offs;
1447 }
1448
1449 /**
1450 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
1451 * @kmap: kernel maps and relocation reference symbol
1452 *
1453 * This function returns %true if we are dealing with the kernel maps and the
1454 * relocation reference symbol has not yet been found. Otherwise %false is
1455 * returned.
1456 */
ref_reloc_sym_not_found(struct kmap * kmap)1457 static bool ref_reloc_sym_not_found(struct kmap *kmap)
1458 {
1459 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
1460 !kmap->ref_reloc_sym->unrelocated_addr;
1461 }
1462
1463 /**
1464 * ref_reloc - kernel relocation offset.
1465 * @kmap: kernel maps and relocation reference symbol
1466 *
1467 * This function returns the offset of kernel addresses as determined by using
1468 * the relocation reference symbol i.e. if the kernel has not been relocated
1469 * then the return value is zero.
1470 */
ref_reloc(struct kmap * kmap)1471 static u64 ref_reloc(struct kmap *kmap)
1472 {
1473 if (kmap && kmap->ref_reloc_sym &&
1474 kmap->ref_reloc_sym->unrelocated_addr)
1475 return kmap->ref_reloc_sym->addr -
1476 kmap->ref_reloc_sym->unrelocated_addr;
1477 return 0;
1478 }
1479
arch__sym_update(struct symbol * s __maybe_unused,GElf_Sym * sym __maybe_unused)1480 void __weak arch__sym_update(struct symbol *s __maybe_unused,
1481 GElf_Sym *sym __maybe_unused) { }
1482
dso__process_kernel_symbol(struct dso * dso,struct map * map,GElf_Sym * sym,GElf_Shdr * shdr,struct maps * kmaps,struct kmap * kmap,struct dso ** curr_dsop,const char * section_name,bool adjust_kernel_syms,bool kmodule,bool * remap_kernel,u64 max_text_sh_offset)1483 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
1484 GElf_Sym *sym, GElf_Shdr *shdr,
1485 struct maps *kmaps, struct kmap *kmap,
1486 struct dso **curr_dsop,
1487 const char *section_name,
1488 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel,
1489 u64 max_text_sh_offset)
1490 {
1491 struct dso *curr_dso = *curr_dsop;
1492 struct map *curr_map;
1493 char dso_name[PATH_MAX];
1494
1495 /* Adjust symbol to map to file offset */
1496 if (adjust_kernel_syms)
1497 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
1498
1499 if (strcmp(section_name, (dso__short_name(curr_dso) + dso__short_name_len(dso))) == 0)
1500 return 0;
1501
1502 if (strcmp(section_name, ".text") == 0) {
1503 /*
1504 * The initial kernel mapping is based on
1505 * kallsyms and identity maps. Overwrite it to
1506 * map to the kernel dso.
1507 */
1508 if (*remap_kernel && dso__kernel(dso) && !kmodule) {
1509 *remap_kernel = false;
1510 map__set_start(map, shdr->sh_addr + ref_reloc(kmap));
1511 map__set_end(map, map__start(map) + shdr->sh_size);
1512 map__set_pgoff(map, shdr->sh_offset);
1513 map__set_mapping_type(map, MAPPING_TYPE__DSO);
1514 /* Ensure maps are correctly ordered */
1515 if (kmaps) {
1516 int err;
1517 struct map *tmp = map__get(map);
1518
1519 maps__remove(kmaps, map);
1520 err = maps__insert(kmaps, map);
1521 map__put(tmp);
1522 if (err)
1523 return err;
1524 }
1525 }
1526
1527 /*
1528 * The initial module mapping is based on
1529 * /proc/modules mapped to offset zero.
1530 * Overwrite it to map to the module dso.
1531 */
1532 if (*remap_kernel && kmodule) {
1533 *remap_kernel = false;
1534 map__set_pgoff(map, shdr->sh_offset);
1535 }
1536
1537 dso__put(*curr_dsop);
1538 *curr_dsop = dso__get(dso);
1539 return 0;
1540 }
1541
1542 if (!kmap)
1543 return 0;
1544
1545 /*
1546 * perf does not record module section addresses except for .text, but
1547 * some sections can use the same mapping as .text.
1548 */
1549 if (kmodule && adjust_kernel_syms && is_exe_text(shdr->sh_flags) &&
1550 shdr->sh_offset <= max_text_sh_offset) {
1551 dso__put(*curr_dsop);
1552 *curr_dsop = dso__get(dso);
1553 return 0;
1554 }
1555
1556 snprintf(dso_name, sizeof(dso_name), "%s%s", dso__short_name(dso), section_name);
1557
1558 curr_map = maps__find_by_name(kmaps, dso_name);
1559 if (curr_map == NULL) {
1560 u64 start = sym->st_value;
1561
1562 if (kmodule)
1563 start += map__start(map) + shdr->sh_offset;
1564
1565 curr_dso = dso__new(dso_name);
1566 if (curr_dso == NULL)
1567 return -1;
1568 dso__set_kernel(curr_dso, dso__kernel(dso));
1569 RC_CHK_ACCESS(curr_dso)->long_name = dso__long_name(dso);
1570 RC_CHK_ACCESS(curr_dso)->long_name_len = dso__long_name_len(dso);
1571 dso__set_binary_type(curr_dso, dso__binary_type(dso));
1572 dso__set_adjust_symbols(curr_dso, dso__adjust_symbols(dso));
1573 curr_map = map__new2(start, curr_dso);
1574 if (curr_map == NULL) {
1575 dso__put(curr_dso);
1576 return -1;
1577 }
1578 if (dso__kernel(curr_dso))
1579 map__kmap(curr_map)->kmaps = kmaps;
1580
1581 if (adjust_kernel_syms) {
1582 map__set_start(curr_map, shdr->sh_addr + ref_reloc(kmap));
1583 map__set_end(curr_map, map__start(curr_map) + shdr->sh_size);
1584 map__set_pgoff(curr_map, shdr->sh_offset);
1585 } else {
1586 map__set_mapping_type(curr_map, MAPPING_TYPE__IDENTITY);
1587 }
1588 dso__set_symtab_type(curr_dso, dso__symtab_type(dso));
1589 if (maps__insert(kmaps, curr_map))
1590 return -1;
1591 dsos__add(&maps__machine(kmaps)->dsos, curr_dso);
1592 dso__set_loaded(curr_dso);
1593 dso__put(*curr_dsop);
1594 *curr_dsop = curr_dso;
1595 } else {
1596 dso__put(*curr_dsop);
1597 *curr_dsop = dso__get(map__dso(curr_map));
1598 }
1599 map__put(curr_map);
1600
1601 return 0;
1602 }
1603
1604 static int
dso__load_sym_internal(struct dso * dso,struct map * map,struct symsrc * syms_ss,struct symsrc * runtime_ss,int kmodule,int dynsym)1605 dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1606 struct symsrc *runtime_ss, int kmodule, int dynsym)
1607 {
1608 struct kmap *kmap = dso__kernel(dso) ? map__kmap(map) : NULL;
1609 struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
1610 struct dso *curr_dso = NULL;
1611 Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;
1612 uint32_t nr_syms;
1613 uint32_t idx;
1614 GElf_Ehdr ehdr;
1615 GElf_Shdr shdr;
1616 GElf_Shdr tshdr;
1617 Elf_Data *syms, *opddata = NULL;
1618 GElf_Sym sym;
1619 Elf_Scn *sec, *sec_strndx;
1620 Elf *elf;
1621 int nr = 0;
1622 bool remap_kernel = false, adjust_kernel_syms = false;
1623 u64 max_text_sh_offset = 0;
1624
1625 if (kmap && !kmaps)
1626 return -1;
1627
1628 elf = syms_ss->elf;
1629 ehdr = syms_ss->ehdr;
1630 if (dynsym) {
1631 sec = syms_ss->dynsym;
1632 shdr = syms_ss->dynshdr;
1633 } else {
1634 sec = syms_ss->symtab;
1635 shdr = syms_ss->symshdr;
1636 }
1637
1638 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1639 ".text", NULL)) {
1640 dso__set_text_offset(dso, tshdr.sh_addr - tshdr.sh_offset);
1641 dso__set_text_end(dso, tshdr.sh_offset + tshdr.sh_size);
1642 }
1643
1644 if (runtime_ss->opdsec)
1645 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1646
1647 syms = elf_getdata(sec, NULL);
1648 if (syms == NULL)
1649 goto out_elf_end;
1650
1651 sec = elf_getscn(elf, shdr.sh_link);
1652 if (sec == NULL)
1653 goto out_elf_end;
1654
1655 symstrs = elf_getdata(sec, NULL);
1656 if (symstrs == NULL)
1657 goto out_elf_end;
1658
1659 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1660 if (sec_strndx == NULL)
1661 goto out_elf_end;
1662
1663 secstrs_run = elf_getdata(sec_strndx, NULL);
1664 if (secstrs_run == NULL)
1665 goto out_elf_end;
1666
1667 sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
1668 if (sec_strndx == NULL)
1669 goto out_elf_end;
1670
1671 secstrs_sym = elf_getdata(sec_strndx, NULL);
1672 if (secstrs_sym == NULL)
1673 goto out_elf_end;
1674
1675 nr_syms = shdr.sh_size / shdr.sh_entsize;
1676
1677 memset(&sym, 0, sizeof(sym));
1678
1679 /*
1680 * The kernel relocation symbol is needed in advance in order to adjust
1681 * kernel maps correctly.
1682 */
1683 if (ref_reloc_sym_not_found(kmap)) {
1684 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1685 const char *elf_name = elf_sym__name(&sym, symstrs);
1686
1687 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1688 continue;
1689 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1690 map__set_reloc(map, kmap->ref_reloc_sym->addr - kmap->ref_reloc_sym->unrelocated_addr);
1691 break;
1692 }
1693 }
1694
1695 /*
1696 * Handle any relocation of vdso necessary because older kernels
1697 * attempted to prelink vdso to its virtual address.
1698 */
1699 if (dso__is_vdso(dso))
1700 map__set_reloc(map, map__start(map) - dso__text_offset(dso));
1701
1702 dso__set_adjust_symbols(dso, runtime_ss->adjust_symbols || ref_reloc(kmap));
1703 /*
1704 * Initial kernel and module mappings do not map to the dso.
1705 * Flag the fixups.
1706 */
1707 if (dso__kernel(dso)) {
1708 remap_kernel = true;
1709 adjust_kernel_syms = dso__adjust_symbols(dso);
1710 }
1711
1712 if (kmodule && adjust_kernel_syms)
1713 max_text_sh_offset = max_text_section(runtime_ss->elf, &runtime_ss->ehdr);
1714
1715 curr_dso = dso__get(dso);
1716 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1717 struct symbol *f;
1718 const char *elf_name = elf_sym__name(&sym, symstrs);
1719 char *demangled = NULL;
1720 int is_label = elf_sym__is_label(&sym);
1721 const char *section_name;
1722 bool used_opd = false;
1723
1724 if (!is_label && !elf_sym__filter(&sym))
1725 continue;
1726
1727 /* Reject ARM ELF "mapping symbols": these aren't unique and
1728 * don't identify functions, so will confuse the profile
1729 * output: */
1730 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1731 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1732 && (elf_name[2] == '\0' || elf_name[2] == '.'))
1733 continue;
1734 }
1735
1736 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1737 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1738 u64 *opd = opddata->d_buf + offset;
1739 sym.st_value = DSO__SWAP(dso, u64, *opd);
1740 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1741 sym.st_value);
1742 used_opd = true;
1743 }
1744
1745 /*
1746 * When loading symbols in a data mapping, ABS symbols (which
1747 * has a value of SHN_ABS in its st_shndx) failed at
1748 * elf_getscn(). And it marks the loading as a failure so
1749 * already loaded symbols cannot be fixed up.
1750 *
1751 * I'm not sure what should be done. Just ignore them for now.
1752 * - Namhyung Kim
1753 */
1754 if (sym.st_shndx == SHN_ABS)
1755 continue;
1756
1757 sec = elf_getscn(syms_ss->elf, sym.st_shndx);
1758 if (!sec)
1759 goto out_elf_end;
1760
1761 gelf_getshdr(sec, &shdr);
1762
1763 /*
1764 * If the attribute bit SHF_ALLOC is not set, the section
1765 * doesn't occupy memory during process execution.
1766 * E.g. ".gnu.warning.*" section is used by linker to generate
1767 * warnings when calling deprecated functions, the symbols in
1768 * the section aren't loaded to memory during process execution,
1769 * so skip them.
1770 */
1771 if (!(shdr.sh_flags & SHF_ALLOC))
1772 continue;
1773
1774 secstrs = secstrs_sym;
1775
1776 /*
1777 * We have to fallback to runtime when syms' section header has
1778 * NOBITS set. NOBITS results in file offset (sh_offset) not
1779 * being incremented. So sh_offset used below has different
1780 * values for syms (invalid) and runtime (valid).
1781 */
1782 if (shdr.sh_type == SHT_NOBITS) {
1783 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1784 if (!sec)
1785 goto out_elf_end;
1786
1787 gelf_getshdr(sec, &shdr);
1788 secstrs = secstrs_run;
1789 }
1790
1791 if (is_label && !elf_sec__filter(&shdr, secstrs))
1792 continue;
1793
1794 section_name = elf_sec__name(&shdr, secstrs);
1795
1796 /* On ARM, symbols for thumb functions have 1 added to
1797 * the symbol address as a flag - remove it */
1798 if ((ehdr.e_machine == EM_ARM) &&
1799 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1800 (sym.st_value & 1))
1801 --sym.st_value;
1802
1803 if (dso__kernel(dso)) {
1804 if (dso__process_kernel_symbol(dso, map, &sym, &shdr,
1805 kmaps, kmap, &curr_dso,
1806 section_name,
1807 adjust_kernel_syms,
1808 kmodule,
1809 &remap_kernel,
1810 max_text_sh_offset))
1811 goto out_elf_end;
1812 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1813 (!used_opd && syms_ss->adjust_symbols)) {
1814 GElf_Phdr phdr;
1815
1816 if (elf_read_program_header(runtime_ss->elf,
1817 (u64)sym.st_value, &phdr)) {
1818 pr_debug4("%s: failed to find program header for "
1819 "symbol: %s st_value: %#" PRIx64 "\n",
1820 __func__, elf_name, (u64)sym.st_value);
1821 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1822 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n",
1823 __func__, (u64)sym.st_value, (u64)shdr.sh_addr,
1824 (u64)shdr.sh_offset);
1825 /*
1826 * Fail to find program header, let's rollback
1827 * to use shdr.sh_addr and shdr.sh_offset to
1828 * calibrate symbol's file address, though this
1829 * is not necessary for normal C ELF file, we
1830 * still need to handle java JIT symbols in this
1831 * case.
1832 */
1833 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1834 } else {
1835 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1836 "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",
1837 __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,
1838 (u64)phdr.p_offset);
1839 sym.st_value -= phdr.p_vaddr - phdr.p_offset;
1840 }
1841 }
1842
1843 demangled = demangle_sym(dso, kmodule, elf_name);
1844 if (demangled != NULL)
1845 elf_name = demangled;
1846
1847 f = symbol__new(sym.st_value, sym.st_size,
1848 GELF_ST_BIND(sym.st_info),
1849 GELF_ST_TYPE(sym.st_info), elf_name);
1850 free(demangled);
1851 if (!f)
1852 goto out_elf_end;
1853
1854 arch__sym_update(f, &sym);
1855
1856 __symbols__insert(dso__symbols(curr_dso), f, dso__kernel(dso));
1857 nr++;
1858 }
1859 dso__put(curr_dso);
1860
1861 /*
1862 * For misannotated, zeroed, ASM function sizes.
1863 */
1864 if (nr > 0) {
1865 symbols__fixup_end(dso__symbols(dso), false);
1866 symbols__fixup_duplicate(dso__symbols(dso));
1867 if (kmap) {
1868 /*
1869 * We need to fixup this here too because we create new
1870 * maps here, for things like vsyscall sections.
1871 */
1872 maps__fixup_end(kmaps);
1873 }
1874 }
1875 return nr;
1876 out_elf_end:
1877 dso__put(curr_dso);
1878 return -1;
1879 }
1880
dso__load_sym(struct dso * dso,struct map * map,struct symsrc * syms_ss,struct symsrc * runtime_ss,int kmodule)1881 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1882 struct symsrc *runtime_ss, int kmodule)
1883 {
1884 int nr = 0;
1885 int err = -1;
1886
1887 dso__set_symtab_type(dso, syms_ss->type);
1888 dso__set_is_64_bit(dso, syms_ss->is_64_bit);
1889 dso__set_rel(dso, syms_ss->ehdr.e_type == ET_REL);
1890
1891 /*
1892 * Modules may already have symbols from kallsyms, but those symbols
1893 * have the wrong values for the dso maps, so remove them.
1894 */
1895 if (kmodule && syms_ss->symtab)
1896 symbols__delete(dso__symbols(dso));
1897
1898 if (!syms_ss->symtab) {
1899 /*
1900 * If the vmlinux is stripped, fail so we will fall back
1901 * to using kallsyms. The vmlinux runtime symbols aren't
1902 * of much use.
1903 */
1904 if (dso__kernel(dso))
1905 return err;
1906 } else {
1907 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1908 kmodule, 0);
1909 if (err < 0)
1910 return err;
1911 nr = err;
1912 }
1913
1914 if (syms_ss->dynsym) {
1915 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1916 kmodule, 1);
1917 if (err < 0)
1918 return err;
1919 nr += err;
1920 }
1921
1922 /*
1923 * The .gnu_debugdata is a special situation: it contains a symbol
1924 * table, but the runtime file may also contain dynsym entries which are
1925 * not present there. We need to load both.
1926 */
1927 if (syms_ss->type == DSO_BINARY_TYPE__GNU_DEBUGDATA && runtime_ss->dynsym) {
1928 err = dso__load_sym_internal(dso, map, runtime_ss, runtime_ss,
1929 kmodule, 1);
1930 if (err < 0)
1931 return err;
1932 nr += err;
1933 }
1934
1935 return nr;
1936 }
1937
elf_read_maps(Elf * elf,bool exe,mapfn_t mapfn,void * data)1938 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1939 {
1940 GElf_Phdr phdr;
1941 size_t i, phdrnum;
1942 int err;
1943 u64 sz;
1944
1945 if (elf_getphdrnum(elf, &phdrnum))
1946 return -1;
1947
1948 for (i = 0; i < phdrnum; i++) {
1949 if (gelf_getphdr(elf, i, &phdr) == NULL)
1950 return -1;
1951 if (phdr.p_type != PT_LOAD)
1952 continue;
1953 if (exe) {
1954 if (!(phdr.p_flags & PF_X))
1955 continue;
1956 } else {
1957 if (!(phdr.p_flags & PF_R))
1958 continue;
1959 }
1960 sz = min(phdr.p_memsz, phdr.p_filesz);
1961 if (!sz)
1962 continue;
1963 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1964 if (err)
1965 return err;
1966 }
1967 return 0;
1968 }
1969
file__read_maps(int fd,bool exe,mapfn_t mapfn,void * data,bool * is_64_bit)1970 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1971 bool *is_64_bit)
1972 {
1973 int err;
1974 Elf *elf;
1975
1976 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1977 if (elf == NULL)
1978 return -1;
1979
1980 if (is_64_bit)
1981 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1982
1983 err = elf_read_maps(elf, exe, mapfn, data);
1984
1985 elf_end(elf);
1986 return err;
1987 }
1988
dso__type_fd(int fd)1989 enum dso_type dso__type_fd(int fd)
1990 {
1991 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1992 GElf_Ehdr ehdr;
1993 Elf_Kind ek;
1994 Elf *elf;
1995
1996 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1997 if (elf == NULL)
1998 goto out;
1999
2000 ek = elf_kind(elf);
2001 if (ek != ELF_K_ELF)
2002 goto out_end;
2003
2004 if (gelf_getclass(elf) == ELFCLASS64) {
2005 dso_type = DSO__TYPE_64BIT;
2006 goto out_end;
2007 }
2008
2009 if (gelf_getehdr(elf, &ehdr) == NULL)
2010 goto out_end;
2011
2012 if (ehdr.e_machine == EM_X86_64)
2013 dso_type = DSO__TYPE_X32BIT;
2014 else
2015 dso_type = DSO__TYPE_32BIT;
2016 out_end:
2017 elf_end(elf);
2018 out:
2019 return dso_type;
2020 }
2021
copy_bytes(int from,off_t from_offs,int to,off_t to_offs,u64 len)2022 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
2023 {
2024 ssize_t r;
2025 size_t n;
2026 int err = -1;
2027 char *buf = malloc(page_size);
2028
2029 if (buf == NULL)
2030 return -1;
2031
2032 if (lseek(to, to_offs, SEEK_SET) != to_offs)
2033 goto out;
2034
2035 if (lseek(from, from_offs, SEEK_SET) != from_offs)
2036 goto out;
2037
2038 while (len) {
2039 n = page_size;
2040 if (len < n)
2041 n = len;
2042 /* Use read because mmap won't work on proc files */
2043 r = read(from, buf, n);
2044 if (r < 0)
2045 goto out;
2046 if (!r)
2047 break;
2048 n = r;
2049 r = write(to, buf, n);
2050 if (r < 0)
2051 goto out;
2052 if ((size_t)r != n)
2053 goto out;
2054 len -= n;
2055 }
2056
2057 err = 0;
2058 out:
2059 free(buf);
2060 return err;
2061 }
2062
2063 struct kcore {
2064 int fd;
2065 int elfclass;
2066 Elf *elf;
2067 GElf_Ehdr ehdr;
2068 };
2069
kcore__open(struct kcore * kcore,const char * filename)2070 static int kcore__open(struct kcore *kcore, const char *filename)
2071 {
2072 GElf_Ehdr *ehdr;
2073
2074 kcore->fd = open(filename, O_RDONLY);
2075 if (kcore->fd == -1)
2076 return -1;
2077
2078 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
2079 if (!kcore->elf)
2080 goto out_close;
2081
2082 kcore->elfclass = gelf_getclass(kcore->elf);
2083 if (kcore->elfclass == ELFCLASSNONE)
2084 goto out_end;
2085
2086 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
2087 if (!ehdr)
2088 goto out_end;
2089
2090 return 0;
2091
2092 out_end:
2093 elf_end(kcore->elf);
2094 out_close:
2095 close(kcore->fd);
2096 return -1;
2097 }
2098
kcore__init(struct kcore * kcore,char * filename,int elfclass,bool temp)2099 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
2100 bool temp)
2101 {
2102 kcore->elfclass = elfclass;
2103
2104 if (temp)
2105 kcore->fd = mkstemp(filename);
2106 else
2107 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
2108 if (kcore->fd == -1)
2109 return -1;
2110
2111 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
2112 if (!kcore->elf)
2113 goto out_close;
2114
2115 if (!gelf_newehdr(kcore->elf, elfclass))
2116 goto out_end;
2117
2118 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
2119
2120 return 0;
2121
2122 out_end:
2123 elf_end(kcore->elf);
2124 out_close:
2125 close(kcore->fd);
2126 unlink(filename);
2127 return -1;
2128 }
2129
kcore__close(struct kcore * kcore)2130 static void kcore__close(struct kcore *kcore)
2131 {
2132 elf_end(kcore->elf);
2133 close(kcore->fd);
2134 }
2135
kcore__copy_hdr(struct kcore * from,struct kcore * to,size_t count)2136 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
2137 {
2138 GElf_Ehdr *ehdr = &to->ehdr;
2139 GElf_Ehdr *kehdr = &from->ehdr;
2140
2141 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
2142 ehdr->e_type = kehdr->e_type;
2143 ehdr->e_machine = kehdr->e_machine;
2144 ehdr->e_version = kehdr->e_version;
2145 ehdr->e_entry = 0;
2146 ehdr->e_shoff = 0;
2147 ehdr->e_flags = kehdr->e_flags;
2148 ehdr->e_phnum = count;
2149 ehdr->e_shentsize = 0;
2150 ehdr->e_shnum = 0;
2151 ehdr->e_shstrndx = 0;
2152
2153 if (from->elfclass == ELFCLASS32) {
2154 ehdr->e_phoff = sizeof(Elf32_Ehdr);
2155 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
2156 ehdr->e_phentsize = sizeof(Elf32_Phdr);
2157 } else {
2158 ehdr->e_phoff = sizeof(Elf64_Ehdr);
2159 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
2160 ehdr->e_phentsize = sizeof(Elf64_Phdr);
2161 }
2162
2163 if (!gelf_update_ehdr(to->elf, ehdr))
2164 return -1;
2165
2166 if (!gelf_newphdr(to->elf, count))
2167 return -1;
2168
2169 return 0;
2170 }
2171
kcore__add_phdr(struct kcore * kcore,int idx,off_t offset,u64 addr,u64 len)2172 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
2173 u64 addr, u64 len)
2174 {
2175 GElf_Phdr phdr = {
2176 .p_type = PT_LOAD,
2177 .p_flags = PF_R | PF_W | PF_X,
2178 .p_offset = offset,
2179 .p_vaddr = addr,
2180 .p_paddr = 0,
2181 .p_filesz = len,
2182 .p_memsz = len,
2183 .p_align = page_size,
2184 };
2185
2186 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
2187 return -1;
2188
2189 return 0;
2190 }
2191
kcore__write(struct kcore * kcore)2192 static off_t kcore__write(struct kcore *kcore)
2193 {
2194 return elf_update(kcore->elf, ELF_C_WRITE);
2195 }
2196
2197 struct phdr_data {
2198 off_t offset;
2199 off_t rel;
2200 u64 addr;
2201 u64 len;
2202 struct list_head node;
2203 struct phdr_data *remaps;
2204 };
2205
2206 struct sym_data {
2207 u64 addr;
2208 struct list_head node;
2209 };
2210
2211 struct kcore_copy_info {
2212 u64 stext;
2213 u64 etext;
2214 u64 first_symbol;
2215 u64 last_symbol;
2216 u64 first_module;
2217 u64 first_module_symbol;
2218 u64 last_module_symbol;
2219 size_t phnum;
2220 struct list_head phdrs;
2221 struct list_head syms;
2222 };
2223
2224 #define kcore_copy__for_each_phdr(k, p) \
2225 list_for_each_entry((p), &(k)->phdrs, node)
2226
phdr_data__new(u64 addr,u64 len,off_t offset)2227 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
2228 {
2229 struct phdr_data *p = zalloc(sizeof(*p));
2230
2231 if (p) {
2232 p->addr = addr;
2233 p->len = len;
2234 p->offset = offset;
2235 }
2236
2237 return p;
2238 }
2239
kcore_copy_info__addnew(struct kcore_copy_info * kci,u64 addr,u64 len,off_t offset)2240 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
2241 u64 addr, u64 len,
2242 off_t offset)
2243 {
2244 struct phdr_data *p = phdr_data__new(addr, len, offset);
2245
2246 if (p)
2247 list_add_tail(&p->node, &kci->phdrs);
2248
2249 return p;
2250 }
2251
kcore_copy__free_phdrs(struct kcore_copy_info * kci)2252 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
2253 {
2254 struct phdr_data *p, *tmp;
2255
2256 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
2257 list_del_init(&p->node);
2258 free(p);
2259 }
2260 }
2261
kcore_copy__new_sym(struct kcore_copy_info * kci,u64 addr)2262 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
2263 u64 addr)
2264 {
2265 struct sym_data *s = zalloc(sizeof(*s));
2266
2267 if (s) {
2268 s->addr = addr;
2269 list_add_tail(&s->node, &kci->syms);
2270 }
2271
2272 return s;
2273 }
2274
kcore_copy__free_syms(struct kcore_copy_info * kci)2275 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
2276 {
2277 struct sym_data *s, *tmp;
2278
2279 list_for_each_entry_safe(s, tmp, &kci->syms, node) {
2280 list_del_init(&s->node);
2281 free(s);
2282 }
2283 }
2284
kcore_copy__process_kallsyms(void * arg,const char * name,char type,u64 start)2285 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
2286 u64 start)
2287 {
2288 struct kcore_copy_info *kci = arg;
2289
2290 if (!kallsyms__is_function(type))
2291 return 0;
2292
2293 if (strchr(name, '[')) {
2294 if (!kci->first_module_symbol || start < kci->first_module_symbol)
2295 kci->first_module_symbol = start;
2296 if (start > kci->last_module_symbol)
2297 kci->last_module_symbol = start;
2298 return 0;
2299 }
2300
2301 if (!kci->first_symbol || start < kci->first_symbol)
2302 kci->first_symbol = start;
2303
2304 if (!kci->last_symbol || start > kci->last_symbol)
2305 kci->last_symbol = start;
2306
2307 if (!strcmp(name, "_stext")) {
2308 kci->stext = start;
2309 return 0;
2310 }
2311
2312 if (!strcmp(name, "_etext")) {
2313 kci->etext = start;
2314 return 0;
2315 }
2316
2317 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
2318 return -1;
2319
2320 return 0;
2321 }
2322
kcore_copy__parse_kallsyms(struct kcore_copy_info * kci,const char * dir)2323 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
2324 const char *dir)
2325 {
2326 char kallsyms_filename[PATH_MAX];
2327
2328 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
2329
2330 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
2331 return -1;
2332
2333 if (kallsyms__parse(kallsyms_filename, kci,
2334 kcore_copy__process_kallsyms) < 0)
2335 return -1;
2336
2337 return 0;
2338 }
2339
kcore_copy__process_modules(void * arg,const char * name __maybe_unused,u64 start,u64 size __maybe_unused)2340 static int kcore_copy__process_modules(void *arg,
2341 const char *name __maybe_unused,
2342 u64 start, u64 size __maybe_unused)
2343 {
2344 struct kcore_copy_info *kci = arg;
2345
2346 if (!kci->first_module || start < kci->first_module)
2347 kci->first_module = start;
2348
2349 return 0;
2350 }
2351
kcore_copy__parse_modules(struct kcore_copy_info * kci,const char * dir)2352 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
2353 const char *dir)
2354 {
2355 char modules_filename[PATH_MAX];
2356
2357 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
2358
2359 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
2360 return -1;
2361
2362 if (modules__parse(modules_filename, kci,
2363 kcore_copy__process_modules) < 0)
2364 return -1;
2365
2366 return 0;
2367 }
2368
kcore_copy__map(struct kcore_copy_info * kci,u64 start,u64 end,u64 pgoff,u64 s,u64 e)2369 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
2370 u64 pgoff, u64 s, u64 e)
2371 {
2372 u64 len, offset;
2373
2374 if (s < start || s >= end)
2375 return 0;
2376
2377 offset = (s - start) + pgoff;
2378 len = e < end ? e - s : end - s;
2379
2380 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
2381 }
2382
kcore_copy__read_map(u64 start,u64 len,u64 pgoff,void * data)2383 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
2384 {
2385 struct kcore_copy_info *kci = data;
2386 u64 end = start + len;
2387 struct sym_data *sdat;
2388
2389 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
2390 return -1;
2391
2392 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
2393 kci->last_module_symbol))
2394 return -1;
2395
2396 list_for_each_entry(sdat, &kci->syms, node) {
2397 u64 s = round_down(sdat->addr, page_size);
2398
2399 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
2400 return -1;
2401 }
2402
2403 return 0;
2404 }
2405
kcore_copy__read_maps(struct kcore_copy_info * kci,Elf * elf)2406 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
2407 {
2408 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
2409 return -1;
2410
2411 return 0;
2412 }
2413
kcore_copy__find_remaps(struct kcore_copy_info * kci)2414 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
2415 {
2416 struct phdr_data *p, *k = NULL;
2417 u64 kend;
2418
2419 if (!kci->stext)
2420 return;
2421
2422 /* Find phdr that corresponds to the kernel map (contains stext) */
2423 kcore_copy__for_each_phdr(kci, p) {
2424 u64 pend = p->addr + p->len - 1;
2425
2426 if (p->addr <= kci->stext && pend >= kci->stext) {
2427 k = p;
2428 break;
2429 }
2430 }
2431
2432 if (!k)
2433 return;
2434
2435 kend = k->offset + k->len;
2436
2437 /* Find phdrs that remap the kernel */
2438 kcore_copy__for_each_phdr(kci, p) {
2439 u64 pend = p->offset + p->len;
2440
2441 if (p == k)
2442 continue;
2443
2444 if (p->offset >= k->offset && pend <= kend)
2445 p->remaps = k;
2446 }
2447 }
2448
kcore_copy__layout(struct kcore_copy_info * kci)2449 static void kcore_copy__layout(struct kcore_copy_info *kci)
2450 {
2451 struct phdr_data *p;
2452 off_t rel = 0;
2453
2454 kcore_copy__find_remaps(kci);
2455
2456 kcore_copy__for_each_phdr(kci, p) {
2457 if (!p->remaps) {
2458 p->rel = rel;
2459 rel += p->len;
2460 }
2461 kci->phnum += 1;
2462 }
2463
2464 kcore_copy__for_each_phdr(kci, p) {
2465 struct phdr_data *k = p->remaps;
2466
2467 if (k)
2468 p->rel = p->offset - k->offset + k->rel;
2469 }
2470 }
2471
kcore_copy__calc_maps(struct kcore_copy_info * kci,const char * dir,Elf * elf)2472 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
2473 Elf *elf)
2474 {
2475 if (kcore_copy__parse_kallsyms(kci, dir))
2476 return -1;
2477
2478 if (kcore_copy__parse_modules(kci, dir))
2479 return -1;
2480
2481 if (kci->stext)
2482 kci->stext = round_down(kci->stext, page_size);
2483 else
2484 kci->stext = round_down(kci->first_symbol, page_size);
2485
2486 if (kci->etext) {
2487 kci->etext = round_up(kci->etext, page_size);
2488 } else if (kci->last_symbol) {
2489 kci->etext = round_up(kci->last_symbol, page_size);
2490 kci->etext += page_size;
2491 }
2492
2493 if (kci->first_module_symbol &&
2494 (!kci->first_module || kci->first_module_symbol < kci->first_module))
2495 kci->first_module = kci->first_module_symbol;
2496
2497 kci->first_module = round_down(kci->first_module, page_size);
2498
2499 if (kci->last_module_symbol) {
2500 kci->last_module_symbol = round_up(kci->last_module_symbol,
2501 page_size);
2502 kci->last_module_symbol += page_size;
2503 }
2504
2505 if (!kci->stext || !kci->etext)
2506 return -1;
2507
2508 if (kci->first_module && !kci->last_module_symbol)
2509 return -1;
2510
2511 if (kcore_copy__read_maps(kci, elf))
2512 return -1;
2513
2514 kcore_copy__layout(kci);
2515
2516 return 0;
2517 }
2518
kcore_copy__copy_file(const char * from_dir,const char * to_dir,const char * name)2519 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
2520 const char *name)
2521 {
2522 char from_filename[PATH_MAX];
2523 char to_filename[PATH_MAX];
2524
2525 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2526 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2527
2528 return copyfile_mode(from_filename, to_filename, 0400);
2529 }
2530
kcore_copy__unlink(const char * dir,const char * name)2531 static int kcore_copy__unlink(const char *dir, const char *name)
2532 {
2533 char filename[PATH_MAX];
2534
2535 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
2536
2537 return unlink(filename);
2538 }
2539
kcore_copy__compare_fds(int from,int to)2540 static int kcore_copy__compare_fds(int from, int to)
2541 {
2542 char *buf_from;
2543 char *buf_to;
2544 ssize_t ret;
2545 size_t len;
2546 int err = -1;
2547
2548 buf_from = malloc(page_size);
2549 buf_to = malloc(page_size);
2550 if (!buf_from || !buf_to)
2551 goto out;
2552
2553 while (1) {
2554 /* Use read because mmap won't work on proc files */
2555 ret = read(from, buf_from, page_size);
2556 if (ret < 0)
2557 goto out;
2558
2559 if (!ret)
2560 break;
2561
2562 len = ret;
2563
2564 if (readn(to, buf_to, len) != (int)len)
2565 goto out;
2566
2567 if (memcmp(buf_from, buf_to, len))
2568 goto out;
2569 }
2570
2571 err = 0;
2572 out:
2573 free(buf_to);
2574 free(buf_from);
2575 return err;
2576 }
2577
kcore_copy__compare_files(const char * from_filename,const char * to_filename)2578 static int kcore_copy__compare_files(const char *from_filename,
2579 const char *to_filename)
2580 {
2581 int from, to, err = -1;
2582
2583 from = open(from_filename, O_RDONLY);
2584 if (from < 0)
2585 return -1;
2586
2587 to = open(to_filename, O_RDONLY);
2588 if (to < 0)
2589 goto out_close_from;
2590
2591 err = kcore_copy__compare_fds(from, to);
2592
2593 close(to);
2594 out_close_from:
2595 close(from);
2596 return err;
2597 }
2598
kcore_copy__compare_file(const char * from_dir,const char * to_dir,const char * name)2599 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
2600 const char *name)
2601 {
2602 char from_filename[PATH_MAX];
2603 char to_filename[PATH_MAX];
2604
2605 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2606 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2607
2608 return kcore_copy__compare_files(from_filename, to_filename);
2609 }
2610
2611 /**
2612 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
2613 * @from_dir: from directory
2614 * @to_dir: to directory
2615 *
2616 * This function copies kallsyms, modules and kcore files from one directory to
2617 * another. kallsyms and modules are copied entirely. Only code segments are
2618 * copied from kcore. It is assumed that two segments suffice: one for the
2619 * kernel proper and one for all the modules. The code segments are determined
2620 * from kallsyms and modules files. The kernel map starts at _stext or the
2621 * lowest function symbol, and ends at _etext or the highest function symbol.
2622 * The module map starts at the lowest module address and ends at the highest
2623 * module symbol. Start addresses are rounded down to the nearest page. End
2624 * addresses are rounded up to the nearest page. An extra page is added to the
2625 * highest kernel symbol and highest module symbol to, hopefully, encompass that
2626 * symbol too. Because it contains only code sections, the resulting kcore is
2627 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
2628 * is not the same for the kernel map and the modules map. That happens because
2629 * the data is copied adjacently whereas the original kcore has gaps. Finally,
2630 * kallsyms file is compared with its copy to check that modules have not been
2631 * loaded or unloaded while the copies were taking place.
2632 *
2633 * Return: %0 on success, %-1 on failure.
2634 */
kcore_copy(const char * from_dir,const char * to_dir)2635 int kcore_copy(const char *from_dir, const char *to_dir)
2636 {
2637 struct kcore kcore;
2638 struct kcore extract;
2639 int idx = 0, err = -1;
2640 off_t offset, sz;
2641 struct kcore_copy_info kci = { .stext = 0, };
2642 char kcore_filename[PATH_MAX];
2643 char extract_filename[PATH_MAX];
2644 struct phdr_data *p;
2645
2646 INIT_LIST_HEAD(&kci.phdrs);
2647 INIT_LIST_HEAD(&kci.syms);
2648
2649 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
2650 return -1;
2651
2652 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
2653 goto out_unlink_kallsyms;
2654
2655 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
2656 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
2657
2658 if (kcore__open(&kcore, kcore_filename))
2659 goto out_unlink_modules;
2660
2661 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
2662 goto out_kcore_close;
2663
2664 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
2665 goto out_kcore_close;
2666
2667 if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
2668 goto out_extract_close;
2669
2670 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
2671 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
2672 offset = round_up(offset, page_size);
2673
2674 kcore_copy__for_each_phdr(&kci, p) {
2675 off_t offs = p->rel + offset;
2676
2677 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
2678 goto out_extract_close;
2679 }
2680
2681 sz = kcore__write(&extract);
2682 if (sz < 0 || sz > offset)
2683 goto out_extract_close;
2684
2685 kcore_copy__for_each_phdr(&kci, p) {
2686 off_t offs = p->rel + offset;
2687
2688 if (p->remaps)
2689 continue;
2690 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
2691 goto out_extract_close;
2692 }
2693
2694 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
2695 goto out_extract_close;
2696
2697 err = 0;
2698
2699 out_extract_close:
2700 kcore__close(&extract);
2701 if (err)
2702 unlink(extract_filename);
2703 out_kcore_close:
2704 kcore__close(&kcore);
2705 out_unlink_modules:
2706 if (err)
2707 kcore_copy__unlink(to_dir, "modules");
2708 out_unlink_kallsyms:
2709 if (err)
2710 kcore_copy__unlink(to_dir, "kallsyms");
2711
2712 kcore_copy__free_phdrs(&kci);
2713 kcore_copy__free_syms(&kci);
2714
2715 return err;
2716 }
2717
kcore_extract__create(struct kcore_extract * kce)2718 int kcore_extract__create(struct kcore_extract *kce)
2719 {
2720 struct kcore kcore;
2721 struct kcore extract;
2722 size_t count = 1;
2723 int idx = 0, err = -1;
2724 off_t offset = page_size, sz;
2725
2726 if (kcore__open(&kcore, kce->kcore_filename))
2727 return -1;
2728
2729 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
2730 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
2731 goto out_kcore_close;
2732
2733 if (kcore__copy_hdr(&kcore, &extract, count))
2734 goto out_extract_close;
2735
2736 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
2737 goto out_extract_close;
2738
2739 sz = kcore__write(&extract);
2740 if (sz < 0 || sz > offset)
2741 goto out_extract_close;
2742
2743 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
2744 goto out_extract_close;
2745
2746 err = 0;
2747
2748 out_extract_close:
2749 kcore__close(&extract);
2750 if (err)
2751 unlink(kce->extract_filename);
2752 out_kcore_close:
2753 kcore__close(&kcore);
2754
2755 return err;
2756 }
2757
kcore_extract__delete(struct kcore_extract * kce)2758 void kcore_extract__delete(struct kcore_extract *kce)
2759 {
2760 unlink(kce->extract_filename);
2761 }
2762
2763 #ifdef HAVE_GELF_GETNOTE_SUPPORT
2764
sdt_adjust_loc(struct sdt_note * tmp,GElf_Addr base_off)2765 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2766 {
2767 if (!base_off)
2768 return;
2769
2770 if (tmp->bit32)
2771 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2772 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2773 tmp->addr.a32[SDT_NOTE_IDX_BASE];
2774 else
2775 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2776 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2777 tmp->addr.a64[SDT_NOTE_IDX_BASE];
2778 }
2779
sdt_adjust_refctr(struct sdt_note * tmp,GElf_Addr base_addr,GElf_Addr base_off)2780 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2781 GElf_Addr base_off)
2782 {
2783 if (!base_off)
2784 return;
2785
2786 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2787 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2788 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2789 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2790 }
2791
2792 /**
2793 * populate_sdt_note : Parse raw data and identify SDT note
2794 * @elf: elf of the opened file
2795 * @data: raw data of a section with description offset applied
2796 * @len: note description size
2797 * @type: type of the note
2798 * @sdt_notes: List to add the SDT note
2799 *
2800 * Responsible for parsing the @data in section .note.stapsdt in @elf and
2801 * if its an SDT note, it appends to @sdt_notes list.
2802 */
populate_sdt_note(Elf ** elf,const char * data,size_t len,struct list_head * sdt_notes)2803 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2804 struct list_head *sdt_notes)
2805 {
2806 const char *provider, *name, *args;
2807 struct sdt_note *tmp = NULL;
2808 GElf_Ehdr ehdr;
2809 GElf_Shdr shdr;
2810 int ret = -EINVAL;
2811
2812 union {
2813 Elf64_Addr a64[NR_ADDR];
2814 Elf32_Addr a32[NR_ADDR];
2815 } buf;
2816
2817 Elf_Data dst = {
2818 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2819 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2820 .d_off = 0, .d_align = 0
2821 };
2822 Elf_Data src = {
2823 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2824 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2825 .d_align = 0
2826 };
2827
2828 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2829 if (!tmp) {
2830 ret = -ENOMEM;
2831 goto out_err;
2832 }
2833
2834 INIT_LIST_HEAD(&tmp->note_list);
2835
2836 if (len < dst.d_size + 3)
2837 goto out_free_note;
2838
2839 /* Translation from file representation to memory representation */
2840 if (gelf_xlatetom(*elf, &dst, &src,
2841 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2842 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2843 goto out_free_note;
2844 }
2845
2846 /* Populate the fields of sdt_note */
2847 provider = data + dst.d_size;
2848
2849 name = (const char *)memchr(provider, '\0', data + len - provider);
2850 if (name++ == NULL)
2851 goto out_free_note;
2852
2853 tmp->provider = strdup(provider);
2854 if (!tmp->provider) {
2855 ret = -ENOMEM;
2856 goto out_free_note;
2857 }
2858 tmp->name = strdup(name);
2859 if (!tmp->name) {
2860 ret = -ENOMEM;
2861 goto out_free_prov;
2862 }
2863
2864 args = memchr(name, '\0', data + len - name);
2865
2866 /*
2867 * There is no argument if:
2868 * - We reached the end of the note;
2869 * - There is not enough room to hold a potential string;
2870 * - The argument string is empty or just contains ':'.
2871 */
2872 if (args == NULL || data + len - args < 2 ||
2873 args[1] == ':' || args[1] == '\0')
2874 tmp->args = NULL;
2875 else {
2876 tmp->args = strdup(++args);
2877 if (!tmp->args) {
2878 ret = -ENOMEM;
2879 goto out_free_name;
2880 }
2881 }
2882
2883 if (gelf_getclass(*elf) == ELFCLASS32) {
2884 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2885 tmp->bit32 = true;
2886 } else {
2887 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2888 tmp->bit32 = false;
2889 }
2890
2891 if (!gelf_getehdr(*elf, &ehdr)) {
2892 pr_debug("%s : cannot get elf header.\n", __func__);
2893 ret = -EBADF;
2894 goto out_free_args;
2895 }
2896
2897 /* Adjust the prelink effect :
2898 * Find out the .stapsdt.base section.
2899 * This scn will help us to handle prelinking (if present).
2900 * Compare the retrieved file offset of the base section with the
2901 * base address in the description of the SDT note. If its different,
2902 * then accordingly, adjust the note location.
2903 */
2904 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2905 sdt_adjust_loc(tmp, shdr.sh_offset);
2906
2907 /* Adjust reference counter offset */
2908 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2909 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2910
2911 list_add_tail(&tmp->note_list, sdt_notes);
2912 return 0;
2913
2914 out_free_args:
2915 zfree(&tmp->args);
2916 out_free_name:
2917 zfree(&tmp->name);
2918 out_free_prov:
2919 zfree(&tmp->provider);
2920 out_free_note:
2921 free(tmp);
2922 out_err:
2923 return ret;
2924 }
2925
2926 /**
2927 * construct_sdt_notes_list : constructs a list of SDT notes
2928 * @elf : elf to look into
2929 * @sdt_notes : empty list_head
2930 *
2931 * Scans the sections in 'elf' for the section
2932 * .note.stapsdt. It, then calls populate_sdt_note to find
2933 * out the SDT events and populates the 'sdt_notes'.
2934 */
construct_sdt_notes_list(Elf * elf,struct list_head * sdt_notes)2935 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2936 {
2937 GElf_Ehdr ehdr;
2938 Elf_Scn *scn = NULL;
2939 Elf_Data *data;
2940 GElf_Shdr shdr;
2941 size_t shstrndx, next;
2942 GElf_Nhdr nhdr;
2943 size_t name_off, desc_off, offset;
2944 int ret = 0;
2945
2946 if (gelf_getehdr(elf, &ehdr) == NULL) {
2947 ret = -EBADF;
2948 goto out_ret;
2949 }
2950 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2951 ret = -EBADF;
2952 goto out_ret;
2953 }
2954
2955 /* Look for the required section */
2956 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2957 if (!scn) {
2958 ret = -ENOENT;
2959 goto out_ret;
2960 }
2961
2962 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2963 ret = -ENOENT;
2964 goto out_ret;
2965 }
2966
2967 data = elf_getdata(scn, NULL);
2968
2969 /* Get the SDT notes */
2970 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2971 &desc_off)) > 0; offset = next) {
2972 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2973 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2974 sizeof(SDT_NOTE_NAME))) {
2975 /* Check the type of the note */
2976 if (nhdr.n_type != SDT_NOTE_TYPE)
2977 goto out_ret;
2978
2979 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2980 nhdr.n_descsz, sdt_notes);
2981 if (ret < 0)
2982 goto out_ret;
2983 }
2984 }
2985 if (list_empty(sdt_notes))
2986 ret = -ENOENT;
2987
2988 out_ret:
2989 return ret;
2990 }
2991
2992 /**
2993 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2994 * @head : empty list_head
2995 * @target : file to find SDT notes from
2996 *
2997 * This opens the file, initializes
2998 * the ELF and then calls construct_sdt_notes_list.
2999 */
get_sdt_note_list(struct list_head * head,const char * target)3000 int get_sdt_note_list(struct list_head *head, const char *target)
3001 {
3002 Elf *elf;
3003 int fd, ret;
3004
3005 fd = open(target, O_RDONLY);
3006 if (fd < 0)
3007 return -EBADF;
3008
3009 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
3010 if (!elf) {
3011 ret = -EBADF;
3012 goto out_close;
3013 }
3014 ret = construct_sdt_notes_list(elf, head);
3015 elf_end(elf);
3016 out_close:
3017 close(fd);
3018 return ret;
3019 }
3020
3021 /**
3022 * cleanup_sdt_note_list : free the sdt notes' list
3023 * @sdt_notes: sdt notes' list
3024 *
3025 * Free up the SDT notes in @sdt_notes.
3026 * Returns the number of SDT notes free'd.
3027 */
cleanup_sdt_note_list(struct list_head * sdt_notes)3028 int cleanup_sdt_note_list(struct list_head *sdt_notes)
3029 {
3030 struct sdt_note *tmp, *pos;
3031 int nr_free = 0;
3032
3033 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
3034 list_del_init(&pos->note_list);
3035 zfree(&pos->args);
3036 zfree(&pos->name);
3037 zfree(&pos->provider);
3038 free(pos);
3039 nr_free++;
3040 }
3041 return nr_free;
3042 }
3043
3044 /**
3045 * sdt_notes__get_count: Counts the number of sdt events
3046 * @start: list_head to sdt_notes list
3047 *
3048 * Returns the number of SDT notes in a list
3049 */
sdt_notes__get_count(struct list_head * start)3050 int sdt_notes__get_count(struct list_head *start)
3051 {
3052 struct sdt_note *sdt_ptr;
3053 int count = 0;
3054
3055 list_for_each_entry(sdt_ptr, start, note_list)
3056 count++;
3057 return count;
3058 }
3059 #endif
3060
symbol__elf_init(void)3061 void symbol__elf_init(void)
3062 {
3063 elf_version(EV_CURRENT);
3064 }
3065