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