text: // SPDX-License-Identifier: GPL-2.0
  #include <fcntl.h>
  #include <stdio.h>
  #include <errno.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  #include <inttypes.h>
  
  #include "dso.h"
  #include "map.h"
  #include "map_groups.h"
  #include "symbol.h"
  #include "symsrc.h"
  #include "demangle-java.h"
  #include "demangle-rust.h"
  #include "machine.h"
  #include "vdso.h"
  #include "debug.h"
  #include "util/copyfile.h"
  #include <linux/ctype.h>
  #include <linux/kernel.h>
  #include <linux/zalloc.h>
  #include <symbol/kallsyms.h>
  #include <internal/lib.h>
  
  #ifndef EM_AARCH64
  #define EM_AARCH64	183  /* ARM 64 bit */
  #endif
  
  #ifndef ELF32_ST_VISIBILITY
  #define ELF32_ST_VISIBILITY(o)	((o) & 0x03)
  #endif
  
  /* For ELF64 the definitions are the same.  */
  #ifndef ELF64_ST_VISIBILITY
  #define ELF64_ST_VISIBILITY(o)	ELF32_ST_VISIBILITY (o)
  #endif
  
  /* How to extract information held in the st_other field.  */
  #ifndef GELF_ST_VISIBILITY
  #define GELF_ST_VISIBILITY(val)	ELF64_ST_VISIBILITY (val)
  #endif
  
  typedef Elf64_Nhdr GElf_Nhdr;
  
  #ifndef DMGL_PARAMS
  #define DMGL_NO_OPTS     0              /* For readability... */
  #define DMGL_PARAMS      (1 << 0)       /* Include function args */
  #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
  #endif
  
  #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  extern char *cplus_demangle(const char *, int);
  
  static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  {
  	return cplus_demangle(c, i);
  }
  #else
  #ifdef NO_DEMANGLE
  static inline char *bfd_demangle(void __maybe_unused *v,
  				 const char __maybe_unused *c,
  				 int __maybe_unused i)
  {
  	return NULL;
  }
  #else
  #define PACKAGE 'perf'
  #include <bfd.h>
  #endif
  #endif
  
  #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  static int elf_getphdrnum(Elf *elf, size_t *dst)
  {
  	GElf_Ehdr gehdr;
  	GElf_Ehdr *ehdr;
  
  	ehdr = gelf_getehdr(elf, &gehdr);
  	if (!ehdr)
  		return -1;
  
  	*dst = ehdr->e_phnum;
  
  	return 0;
  }
  #endif
  
  #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  {
  	pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  	return -1;
  }
  #endif
  
  #ifndef NT_GNU_BUILD_ID
  #define NT_GNU_BUILD_ID 3
  #endif
  
  /**
   * elf_symtab__for_each_symbol - iterate thru all the symbols
   *
   * @syms: struct elf_symtab instance to iterate
   * @idx: uint32_t idx
   * @sym: GElf_Sym iterator
   */
  #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  	for (idx = 0, gelf_getsym(syms, idx, &sym);\
  	     idx < nr_syms; \
  	     idx++, gelf_getsym(syms, idx, &sym))
  
  static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  {
  	return GELF_ST_TYPE(sym->st_info);
  }
  
  static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
  {
  	return GELF_ST_VISIBILITY(sym->st_other);
  }
  
  #ifndef STT_GNU_IFUNC
  #define STT_GNU_IFUNC 10
  #endif
  
  static inline int elf_sym__is_function(const GElf_Sym *sym)
  {
  	return (elf_sym__type(sym) == STT_FUNC ||
  		elf_sym__type(sym) == STT_GNU_IFUNC) &&
  	       sym->st_name != 0 &&
  	       sym->st_shndx != SHN_UNDEF;
  }
  
  static inline bool elf_sym__is_object(const GElf_Sym *sym)
  {
  	return elf_sym__type(sym) == STT_OBJECT &&
  		sym->st_name != 0 &&
  		sym->st_shndx != SHN_UNDEF;
  }
  
  static inline int elf_sym__is_label(const GElf_Sym *sym)
  {
  	return elf_sym__type(sym) == STT_NOTYPE &&
  		sym->st_name != 0 &&
  		sym->st_shndx != SHN_UNDEF &&
  		sym->st_shndx != SHN_ABS &&
  		elf_sym__visibility(sym) != STV_HIDDEN &&
  		elf_sym__visibility(sym) != STV_INTERNAL;
  }
  
  static bool elf_sym__filter(GElf_Sym *sym)
  {
  	return elf_sym__is_function(sym) || elf_sym__is_object(sym);
  }
  
  static inline const char *elf_sym__name(const GElf_Sym *sym,
  					const Elf_Data *symstrs)
  {
  	return symstrs->d_buf + sym->st_name;
  }
  
  static inline const char *elf_sec__name(const GElf_Shdr *shdr,
  					const Elf_Data *secstrs)
  {
  	return secstrs->d_buf + shdr->sh_name;
  }
  
  static inline int elf_sec__is_text(const GElf_Shdr *shdr,
  					const Elf_Data *secstrs)
  {
  	return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
  }
  
  static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
  				    const Elf_Data *secstrs)
  {
  	return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
  }
  
  static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
  {
  	return elf_sec__is_text(shdr, secstrs) || 
  	       elf_sec__is_data(shdr, secstrs);
  }
  
  static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
  {
  	Elf_Scn *sec = NULL;
  	GElf_Shdr shdr;
  	size_t cnt = 1;
  
  	while ((sec = elf_nextscn(elf, sec)) != NULL) {
  		gelf_getshdr(sec, &shdr);
  
  		if ((addr >= shdr.sh_addr) &&
  		    (addr < (shdr.sh_addr + shdr.sh_size)))
  			return cnt;
  
  		++cnt;
  	}
  
  	return -1;
  }
  
  Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
  			     GElf_Shdr *shp, const char *name, size_t *idx)
  {
  	Elf_Scn *sec = NULL;
  	size_t cnt = 1;
  
  	/* Elf is corrupted/truncated, avoid calling elf_strptr. */
  	if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
  		return NULL;
  
  	while ((sec = elf_nextscn(elf, sec)) != NULL) {
  		char *str;
  
  		gelf_getshdr(sec, shp);
  		str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
  		if (str && !strcmp(name, str)) {
  			if (idx)
  				*idx = cnt;
  			return sec;
  		}
  		++cnt;
  	}
  
  	return NULL;
  }
  
  static bool want_demangle(bool is_kernel_sym)
  {
  	return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
  }
  
  static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
  {
  	int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
  	char *demangled = NULL;
  
  	/*
  	 * We need to figure out if the object was created from C++ sources
  	 * DWARF DW_compile_unit has this, but we don't always have access
  	 * to it...
  	 */
  	if (!want_demangle(dso->kernel || kmodule))
  	    return demangled;
  
  	demangled = bfd_demangle(NULL, elf_name, demangle_flags);
  	if (demangled == NULL)
  		demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
  	else if (rust_is_mangled(demangled))
  		/*
  		    * Input to Rust demangling is the BFD-demangled
  		    * name which it Rust-demangles in place.
  		    */
  		rust_demangle_sym(demangled);
  
  	return demangled;
  }
  
  #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
  	for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
  	     idx < nr_entries; \
  	     ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
  
  #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
  	for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
  	     idx < nr_entries; \
  	     ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
  
  /*
   * We need to check if we have a .dynsym, so that we can handle the
   * .plt, synthesizing its symbols, that aren't on the symtabs (be it
   * .dynsym or .symtab).
   * And always look at the original dso, not at debuginfo packages, that
   * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
   */
  int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
  {
  	uint32_t nr_rel_entries, idx;
  	GElf_Sym sym;
  	u64 plt_offset, plt_header_size, plt_entry_size;
  	GElf_Shdr shdr_plt;
  	struct symbol *f;
  	GElf_Shdr shdr_rel_plt, shdr_dynsym;
  	Elf_Data *reldata, *syms, *symstrs;
  	Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
  	size_t dynsym_idx;
  	GElf_Ehdr ehdr;
  	char sympltname[1024];
  	Elf *elf;
  	int nr = 0, symidx, err = 0;
  
  	if (!ss->dynsym)
  		return 0;
  
  	elf = ss->elf;
  	ehdr = ss->ehdr;
  
  	scn_dynsym = ss->dynsym;
  	shdr_dynsym = ss->dynshdr;
  	dynsym_idx = ss->dynsym_idx;
  
  	if (scn_dynsym == NULL)
  		goto out_elf_end;
  
  	scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
  					  ".rela.plt", NULL);
  	if (scn_plt_rel == NULL) {
  		scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
  						  ".rel.plt", NULL);
  		if (scn_plt_rel == NULL)
  			goto out_elf_end;
  	}
  
  	err = -1;
  
  	if (shdr_rel_plt.sh_link != dynsym_idx)
  		goto out_elf_end;
  
  	if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
  		goto out_elf_end;
  
  	/*
  	 * Fetch the relocation section to find the idxes to the GOT
  	 * and the symbols in the .dynsym they refer to.
  	 */
  	reldata = elf_getdata(scn_plt_rel, NULL);
  	if (reldata == NULL)
  		goto out_elf_end;
  
  	syms = elf_getdata(scn_dynsym, NULL);
  	if (syms == NULL)
  		goto out_elf_end;
  
  	scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
  	if (scn_symstrs == NULL)
  		goto out_elf_end;
  
  	symstrs = elf_getdata(scn_symstrs, NULL);
  	if (symstrs == NULL)
  		goto out_elf_end;
  
  	if (symstrs->d_size == 0)
  		goto out_elf_end;
  
  	nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
  	plt_offset = shdr_plt.sh_offset;
  	switch (ehdr.e_machine) {
  		case EM_ARM:
  			plt_header_size = 20;
  			plt_entry_size = 12;
  			break;
  
  		case EM_AARCH64:
  			plt_header_size = 32;
  			plt_entry_size = 16;
  			break;
  
  		case EM_SPARC:
  			plt_header_size = 48;
  			plt_entry_size = 12;
  			break;
  
  		case EM_SPARCV9:
  			plt_header_size = 128;
  			plt_entry_size = 32;
  			break;
  
  		default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
  			plt_header_size = shdr_plt.sh_entsize;
  			plt_entry_size = shdr_plt.sh_entsize;
  			break;
  	}
  	plt_offset += plt_header_size;
  
  	if (shdr_rel_plt.sh_type == SHT_RELA) {
  		GElf_Rela pos_mem, *pos;
  
  		elf_section__for_each_rela(reldata, pos, pos_mem, idx,
  					   nr_rel_entries) {
  			const char *elf_name = NULL;
  			char *demangled = NULL;
  			symidx = GELF_R_SYM(pos->r_info);
  			gelf_getsym(syms, symidx, &sym);
  
  			elf_name = elf_sym__name(&sym, symstrs);
  			demangled = demangle_sym(dso, 0, elf_name);
  			if (demangled != NULL)
  				elf_name = demangled;
  			snprintf(sympltname, sizeof(sympltname),
  				 "%s@plt", elf_name);
  			free(demangled);
  
  			f = symbol__new(plt_offset, plt_entry_size,
  					STB_GLOBAL, STT_FUNC, sympltname);
  			if (!f)
  				goto out_elf_end;
  
  			plt_offset += plt_entry_size;
  			symbols__insert(&dso->symbols, f);
  			++nr;
  		}
  	} else if (shdr_rel_plt.sh_type == SHT_REL) {
  		GElf_Rel pos_mem, *pos;
  		elf_section__for_each_rel(reldata, pos, pos_mem, idx,
  					  nr_rel_entries) {
  			const char *elf_name = NULL;
  			char *demangled = NULL;
  			symidx = GELF_R_SYM(pos->r_info);
  			gelf_getsym(syms, symidx, &sym);
  
  			elf_name = elf_sym__name(&sym, symstrs);
  			demangled = demangle_sym(dso, 0, elf_name);
  			if (demangled != NULL)
  				elf_name = demangled;
  			snprintf(sympltname, sizeof(sympltname),
  				 "%s@plt", elf_name);
  			free(demangled);
  
  			f = symbol__new(plt_offset, plt_entry_size,
  					STB_GLOBAL, STT_FUNC, sympltname);
  			if (!f)
  				goto out_elf_end;
  
  			plt_offset += plt_entry_size;
  			symbols__insert(&dso->symbols, f);
  			++nr;
  		}
  	}
  
  	err = 0;
  out_elf_end:
  	if (err == 0)
  		return nr;
  	pr_debug("%s: problems reading %s PLT info.\n",
  		 __func__, dso->long_name);
  	return 0;
  }
  
  char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
  {
  	return demangle_sym(dso, kmodule, elf_name);
  }
  
  /*
   * Align offset to 4 bytes as needed for note name and descriptor data.
   */
  #define NOTE_ALIGN(n) (((n) + 3) & -4U)
  
  static int elf_read_build_id(Elf *elf, void *bf, size_t size)
  {
  	int err = -1;
  	GElf_Ehdr ehdr;
  	GElf_Shdr shdr;
  	Elf_Data *data;
  	Elf_Scn *sec;
  	Elf_Kind ek;
  	void *ptr;
  
  	if (size < BUILD_ID_SIZE)
  		goto out;
  
  	ek = elf_kind(elf);
  	if (ek != ELF_K_ELF)
  		goto out;
  
  	if (gelf_getehdr(elf, &ehdr) == NULL) {
  		pr_err("%s: cannot get elf header.\n", __func__);
  		goto out;
  	}
  
  	/*
  	 * Check following sections for notes:
  	 *   '.note.gnu.build-id'
  	 *   '.notes'
  	 *   '.note' (VDSO specific)
  	 */
  	do {
  		sec = elf_section_by_name(elf, &ehdr, &shdr,
  					  ".note.gnu.build-id", NULL);
  		if (sec)
  			break;
  
  		sec = elf_section_by_name(elf, &ehdr, &shdr,
  					  ".notes", NULL);
  		if (sec)
  			break;
  
  		sec = elf_section_by_name(elf, &ehdr, &shdr,
  					  ".note", NULL);
  		if (sec)
  			break;
  
  		return err;
  
  	} while (0);
  
  	data = elf_getdata(sec, NULL);
  	if (data == NULL)
  		goto out;
  
  	ptr = data->d_buf;
  	while (ptr < (data->d_buf + data->d_size)) {
  		GElf_Nhdr *nhdr = ptr;
  		size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
  		       descsz = NOTE_ALIGN(nhdr->n_descsz);
  		const char *name;
  
  		ptr += sizeof(*nhdr);
  		name = ptr;
  		ptr += namesz;
  		if (nhdr->n_type == NT_GNU_BUILD_ID &&
  		    nhdr->n_namesz == sizeof("GNU")) {
  			if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
  				size_t sz = min(size, descsz);
  				memcpy(bf, ptr, sz);
  				memset(bf + sz, 0, size - sz);
  				err = descsz;
  				break;
  			}
  		}
  		ptr += descsz;
  	}
  
  out:
  	return err;
  }
  
  int filename__read_build_id(const char *filename, void *bf, size_t size)
  {
  	int fd, err = -1;
  	Elf *elf;
  
  	if (size < BUILD_ID_SIZE)
  		goto out;
  
  	fd = open(filename, O_RDONLY);
  	if (fd < 0)
  		goto out;
  
  	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
  	if (elf == NULL) {
  		pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
  		goto out_close;
  	}
  
  	err = elf_read_build_id(elf, bf, size);
  
  	elf_end(elf);
  out_close:
  	close(fd);
  out:
  	return err;
  }
  
  int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
  {
  	int fd, err = -1;
  
  	if (size < BUILD_ID_SIZE)
  		goto out;
  
  	fd = open(filename, O_RDONLY);
  	if (fd < 0)
  		goto out;
  
  	while (1) {
  		char bf[BUFSIZ];
  		GElf_Nhdr nhdr;
  		size_t namesz, descsz;
  
  		if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
  			break;
  
  		namesz = NOTE_ALIGN(nhdr.n_namesz);
  		descsz = NOTE_ALIGN(nhdr.n_descsz);
  		if (nhdr.n_type == NT_GNU_BUILD_ID &&
  		    nhdr.n_namesz == sizeof("GNU")) {
  			if (read(fd, bf, namesz) != (ssize_t)namesz)
  				break;
  			if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
  				size_t sz = min(descsz, size);
  				if (read(fd, build_id, sz) == (ssize_t)sz) {
  					memset(build_id + sz, 0, size - sz);
  					err = 0;
  					break;
  				}
  			} else if (read(fd, bf, descsz) != (ssize_t)descsz)
  				break;
  		} else {
  			int n = namesz + descsz;
  
  			if (n > (int)sizeof(bf)) {
  				n = sizeof(bf);
  				pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
  					 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
  			}
  			if (read(fd, bf, n) != n)
  				break;
  		}
  	}
  	close(fd);
  out:
  	return err;
  }
  
  int filename__read_debuglink(const char *filename, char *debuglink,
  			     size_t size)
  {
  	int fd, err = -1;
  	Elf *elf;
  	GElf_Ehdr ehdr;
  	GElf_Shdr shdr;
  	Elf_Data *data;
  	Elf_Scn *sec;
  	Elf_Kind ek;
  
  	fd = open(filename, O_RDONLY);
  	if (fd < 0)
  		goto out;
  
  	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
  	if (elf == NULL) {
  		pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
  		goto out_close;
  	}
  
  	ek = elf_kind(elf);
  	if (ek != ELF_K_ELF)
  		goto out_elf_end;
  
  	if (gelf_getehdr(elf, &ehdr) == NULL) {
  		pr_err("%s: cannot get elf header.\n", __func__);
  		goto out_elf_end;
  	}
  
  	sec = elf_section_by_name(elf, &ehdr, &shdr,
  				  ".gnu_debuglink", NULL);
  	if (sec == NULL)
  		goto out_elf_end;
  
  	data = elf_getdata(sec, NULL);
  	if (data == NULL)
  		goto out_elf_end;
  
  	/* the start of this section is a zero-terminated string */
  	strncpy(debuglink, data->d_buf, size);
  
  	err = 0;
  
  out_elf_end:
  	elf_end(elf);
  out_close:
  	close(fd);
  out:
  	return err;
  }
  
  static int dso__swap_init(struct dso *dso, unsigned char eidata)
  {
  	static unsigned int const endian = 1;
  
  	dso->needs_swap = DSO_SWAP__NO;
  
  	switch (eidata) {
  	case ELFDATA2LSB:
  		/* We are big endian, DSO is little endian. */
  		if (*(unsigned char const *)&endian != 1)
  			dso->needs_swap = DSO_SWAP__YES;
  		break;
  
  	case ELFDATA2MSB:
  		/* We are little endian, DSO is big endian. */
  		if (*(unsigned char const *)&endian != 0)
  			dso->needs_swap = DSO_SWAP__YES;
  		break;
  
  	default:
  		pr_err("unrecognized DSO data encoding %d\n", eidata);
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  bool symsrc__possibly_runtime(struct symsrc *ss)
  {
  	return ss->dynsym || ss->opdsec;
  }
  
  bool symsrc__has_symtab(struct symsrc *ss)
  {
  	return ss->symtab != NULL;
  }
  
  void symsrc__destroy(struct symsrc *ss)
  {
  	zfree(&ss->name);
  	elf_end(ss->elf);
  	close(ss->fd);
  }
  
  bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
  {
  	return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
  }
  
  int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
  		 enum dso_binary_type type)
  {
  	GElf_Ehdr ehdr;
  	Elf *elf;
  	int fd;
  
  	if (dso__needs_decompress(dso)) {
  		fd = dso__decompress_kmodule_fd(dso, name);
  		if (fd < 0)
  			return -1;
  
  		type = dso->symtab_type;
  	} else {
  		fd = open(name, O_RDONLY);
  		if (fd < 0) {
  			dso->load_errno = errno;
  			return -1;
  		}
  	}
  
  	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
  	if (elf == NULL) {
  		pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
  		dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
  		goto out_close;
  	}
  
  	if (gelf_getehdr(elf, &ehdr) == NULL) {
  		dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
  		pr_debug("%s: cannot get elf header.\n", __func__);
  		goto out_elf_end;
  	}
  
  	if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
  		dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
  		goto out_elf_end;
  	}
  
  	/* Always reject images with a mismatched build-id: */
  	if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
  		u8 build_id[BUILD_ID_SIZE];
  
  		if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
  			dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
  			goto out_elf_end;
  		}
  
  		if (!dso__build_id_equal(dso, build_id)) {
  			pr_debug("%s: build id mismatch for %s.\n", __func__, name);
  			dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
  			goto out_elf_end;
  		}
  	}
  
  	ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
  
  	ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
  			NULL);
  	if (ss->symshdr.sh_type != SHT_SYMTAB)
  		ss->symtab = NULL;
  
  	ss->dynsym_idx = 0;
  	ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
  			&ss->dynsym_idx);
  	if (ss->dynshdr.sh_type != SHT_DYNSYM)
  		ss->dynsym = NULL;
  
  	ss->opdidx = 0;
  	ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
  			&ss->opdidx);
  	if (ss->opdshdr.sh_type != SHT_PROGBITS)
  		ss->opdsec = NULL;
  
  	if (dso->kernel == DSO_TYPE_USER)
  		ss->adjust_symbols = true;
  	else
  		ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
  
  	ss->name   = strdup(name);
  	if (!ss->name) {
  		dso->load_errno = errno;
  		goto out_elf_end;
  	}
  
  	ss->elf    = elf;
  	ss->fd     = fd;
  	ss->ehdr   = ehdr;
  	ss->type   = type;
  
  	return 0;
  
  out_elf_end:
  	elf_end(elf);
  out_close:
  	close(fd);
  	return -1;
  }
  
  /**
   * ref_reloc_sym_not_found - has kernel relocation symbol been found.
   * @kmap: kernel maps and relocation reference symbol
   *
   * This function returns %true if we are dealing with the kernel maps and the
   * relocation reference symbol has not yet been found.  Otherwise %false is
   * returned.
   */
  static bool ref_reloc_sym_not_found(struct kmap *kmap)
  {
  	return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
  	       !kmap->ref_reloc_sym->unrelocated_addr;
  }
  
  /**
   * ref_reloc - kernel relocation offset.
   * @kmap: kernel maps and relocation reference symbol
   *
   * This function returns the offset of kernel addresses as determined by using
   * the relocation reference symbol i.e. if the kernel has not been relocated
   * then the return value is zero.
   */
  static u64 ref_reloc(struct kmap *kmap)
  {
  	if (kmap && kmap->ref_reloc_sym &&
  	    kmap->ref_reloc_sym->unrelocated_addr)
  		return kmap->ref_reloc_sym->addr -
  		       kmap->ref_reloc_sym->unrelocated_addr;
  	return 0;
  }
  
  void __weak arch__sym_update(struct symbol *s __maybe_unused,
  		GElf_Sym *sym __maybe_unused) { }
  
  static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
  				      GElf_Sym *sym, GElf_Shdr *shdr,
  				      struct map_groups *kmaps, struct kmap *kmap,
  				      struct dso **curr_dsop, struct map **curr_mapp,
  				      const char *section_name,
  				      bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
  {
  	struct dso *curr_dso = *curr_dsop;
  	struct map *curr_map;
  	char dso_name[PATH_MAX];
  
  	/* Adjust symbol to map to file offset */
  	if (adjust_kernel_syms)
  		sym->st_value -= shdr->sh_addr - shdr->sh_offset;
  
  	if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
  		return 0;
  
  	if (strcmp(section_name, ".text") == 0) {
  		/*
  		 * The initial kernel mapping is based on
  		 * kallsyms and identity maps.  Overwrite it to
  		 * map to the kernel dso.
  		 */
  		if (*remap_kernel && dso->kernel) {
  			*remap_kernel = false;
  			map->start = shdr->sh_addr + ref_reloc(kmap);
  			map->end = map->start + shdr->sh_size;
  			map->pgoff = shdr->sh_offset;
  			map->map_ip = map__map_ip;
  			map->unmap_ip = map__unmap_ip;
  			/* Ensure maps are correctly ordered */
  			if (kmaps) {
  				map__get(map);
  				map_groups__remove(kmaps, map);
  				map_groups__insert(kmaps, map);
  				map__put(map);
  			}
  		}
  
  		/*
  		 * The initial module mapping is based on
  		 * /proc/modules mapped to offset zero.
  		 * Overwrite it to map to the module dso.
  		 */
  		if (*remap_kernel && kmodule) {
  			*remap_kernel = false;
  			map->pgoff = shdr->sh_offset;
  		}
  
  		*curr_mapp = map;
  		*curr_dsop = dso;
  		return 0;
  	}
  
  	if (!kmap)
  		return 0;
  
  	snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
  
  	curr_map = map_groups__find_by_name(kmaps, dso_name);
  	if (curr_map == NULL) {
  		u64 start = sym->st_value;
  
  		if (kmodule)
  			start += map->start + shdr->sh_offset;
  
  		curr_dso = dso__new(dso_name);
  		if (curr_dso == NULL)
  			return -1;
  		curr_dso->kernel = dso->kernel;
  		curr_dso->long_name = dso->long_name;
  		curr_dso->long_name_len = dso->long_name_len;
  		curr_map = map__new2(start, curr_dso);
  		dso__put(curr_dso);
  		if (curr_map == NULL)
  			return -1;
  
  		if (adjust_kernel_syms) {
  			curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
  			curr_map->end	 = curr_map->start + shdr->sh_size;
  			curr_map->pgoff	 = shdr->sh_offset;
  		} else {
  			curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
  		}
  		curr_dso->symtab_type = dso->symtab_type;
  		map_groups__insert(kmaps, curr_map);
  		/*
  		 * Add it before we drop the referece to curr_map, i.e. while
  		 * we still are sure to have a reference to this DSO via
  		 * *curr_map->dso.
  		 */
  		dsos__add(&map->groups->machine->dsos, curr_dso);
  		/* kmaps already got it */
  		map__put(curr_map);
  		dso__set_loaded(curr_dso);
  		*curr_mapp = curr_map;
  		*curr_dsop = curr_dso;
  	} else
  		*curr_dsop = curr_map->dso;
  
  	return 0;
  }
  
  int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
  		  struct symsrc *runtime_ss, int kmodule)
  {
  	struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
  	struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
  	struct map *curr_map = map;
  	struct dso *curr_dso = dso;
  	Elf_Data *symstrs, *secstrs;
  	uint32_t nr_syms;
  	int err = -1;
  	uint32_t idx;
  	GElf_Ehdr ehdr;
  	GElf_Shdr shdr;
  	GElf_Shdr tshdr;
  	Elf_Data *syms, *opddata = NULL;
  	GElf_Sym sym;
  	Elf_Scn *sec, *sec_strndx;
  	Elf *elf;
  	int nr = 0;
  	bool remap_kernel = false, adjust_kernel_syms = false;
  
  	if (kmap && !kmaps)
  		return -1;
  
  	dso->symtab_type = syms_ss->type;
  	dso->is_64_bit = syms_ss->is_64_bit;
  	dso->rel = syms_ss->ehdr.e_type == ET_REL;
  
  	/*
  	 * Modules may already have symbols from kallsyms, but those symbols
  	 * have the wrong values for the dso maps, so remove them.
  	 */
  	if (kmodule && syms_ss->symtab)
  		symbols__delete(&dso->symbols);
  
  	if (!syms_ss->symtab) {
  		/*
  		 * If the vmlinux is stripped, fail so we will fall back
  		 * to using kallsyms. The vmlinux runtime symbols aren't
  		 * of much use.
  		 */
  		if (dso->kernel)
  			goto out_elf_end;
  
  		syms_ss->symtab  = syms_ss->dynsym;
  		syms_ss->symshdr = syms_ss->dynshdr;
  	}
  
  	elf = syms_ss->elf;
  	ehdr = syms_ss->ehdr;
  	sec = syms_ss->symtab;
  	shdr = syms_ss->symshdr;
  
  	if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
  				".text", NULL))
  		dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
  
  	if (runtime_ss->opdsec)
  		opddata = elf_rawdata(runtime_ss->opdsec, NULL);
  
  	syms = elf_getdata(sec, NULL);
  	if (syms == NULL)
  		goto out_elf_end;
  
  	sec = elf_getscn(elf, shdr.sh_link);
  	if (sec == NULL)
  		goto out_elf_end;
  
  	symstrs = elf_getdata(sec, NULL);
  	if (symstrs == NULL)
  		goto out_elf_end;
  
  	sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
  	if (sec_strndx == NULL)
  		goto out_elf_end;
  
  	secstrs = elf_getdata(sec_strndx, NULL);
  	if (secstrs == NULL)
  		goto out_elf_end;
  
  	nr_syms = shdr.sh_size / shdr.sh_entsize;
  
  	memset(&sym, 0, sizeof(sym));
  
  	/*
  	 * The kernel relocation symbol is needed in advance in order to adjust
  	 * kernel maps correctly.
  	 */
  	if (ref_reloc_sym_not_found(kmap)) {
  		elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
  			const char *elf_name = elf_sym__name(&sym, symstrs);
  
  			if (strcmp(elf_name, kmap->ref_reloc_sym->name))
  				continue;
  			kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
  			map->reloc = kmap->ref_reloc_sym->addr -
  				     kmap->ref_reloc_sym->unrelocated_addr;
  			break;
  		}
  	}
  
  	/*
  	 * Handle any relocation of vdso necessary because older kernels
  	 * attempted to prelink vdso to its virtual address.
  	 */
  	if (dso__is_vdso(dso))
  		map->reloc = map->start - dso->text_offset;
  
  	dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
  	/*
  	 * Initial kernel and module mappings do not map to the dso.
  	 * Flag the fixups.
  	 */
  	if (dso->kernel || kmodule) {
  		remap_kernel = true;
  		adjust_kernel_syms = dso->adjust_symbols;
  	}
  	elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
  		struct symbol *f;
  		const char *elf_name = elf_sym__name(&sym, symstrs);
  		char *demangled = NULL;
  		int is_label = elf_sym__is_label(&sym);
  		const char *section_name;
  		bool used_opd = false;
  
  		if (!is_label && !elf_sym__filter(&sym))
  			continue;
  
  		/* Reject ARM ELF "mapping symbols": these aren't unique and
  		 * don't identify functions, so will confuse the profile
  		 * output: */
  		if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
  			if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
  			    && (elf_name[2] == '\0' || elf_name[2] == '.'))
  				continue;
  		}
  
  		if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
  			u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
  			u64 *opd = opddata->d_buf + offset;
  			sym.st_value = DSO__SWAP(dso, u64, *opd);
  			sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
  					sym.st_value);
  			used_opd = true;
  		}
  		/*
  		 * When loading symbols in a data mapping, ABS symbols (which
  		 * has a value of SHN_ABS in its st_shndx) failed at
  		 * elf_getscn().  And it marks the loading as a failure so
  		 * already loaded symbols cannot be fixed up.
  		 *
  		 * I'm not sure what should be done. Just ignore them for now.
  		 * - Namhyung Kim
  		 */
  		if (sym.st_shndx == SHN_ABS)
  			continue;
  
  		sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
  		if (!sec)
  			goto out_elf_end;
  
  		gelf_getshdr(sec, &shdr);
  
  		if (is_label && !elf_sec__filter(&shdr, secstrs))
  			continue;
  
  		section_name = elf_sec__name(&shdr, secstrs);
  
  		/* On ARM, symbols for thumb functions have 1 added to
  		 * the symbol address as a flag - remove it */
  		if ((ehdr.e_machine == EM_ARM) &&
  		    (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
  		    (sym.st_value & 1))
  			--sym.st_value;
  
  		if (dso->kernel || kmodule) {
  			if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
  						       section_name, adjust_kernel_syms, kmodule, &remap_kernel))
  				goto out_elf_end;
  		} else if ((used_opd && runtime_ss->adjust_symbols) ||
  			   (!used_opd && syms_ss->adjust_symbols)) {
  			pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
  				  "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
  				  (u64)sym.st_value, (u64)shdr.sh_addr,
  				  (u64)shdr.sh_offset);
  			sym.st_value -= shdr.sh_addr - shdr.sh_offset;
  		}
  
  		demangled = demangle_sym(dso, kmodule, elf_name);
  		if (demangled != NULL)
  			elf_name = demangled;
  
  		f = symbol__new(sym.st_value, sym.st_size,
  				GELF_ST_BIND(sym.st_info),
  				GELF_ST_TYPE(sym.st_info), elf_name);
  		free(demangled);
  		if (!f)
  			goto out_elf_end;
  
  		arch__sym_update(f, &sym);
  
  		__symbols__insert(&curr_dso->symbols, f, dso->kernel);
  		nr++;
  	}
  
  	/*
  	 * For misannotated, zeroed, ASM function sizes.
  	 */
  	if (nr > 0) {
  		symbols__fixup_end(&dso->symbols);
  		symbols__fixup_duplicate(&dso->symbols);
  		if (kmap) {
  			/*
  			 * We need to fixup this here too because we create new
  			 * maps here, for things like vsyscall sections.
  			 */
  			map_groups__fixup_end(kmaps);
  		}
  	}
  	err = nr;
  out_elf_end:
  	return err;
  }
  
  static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
  {
  	GElf_Phdr phdr;
  	size_t i, phdrnum;
  	int err;
  	u64 sz;
  
  	if (elf_getphdrnum(elf, &phdrnum))
  		return -1;
  
  	for (i = 0; i < phdrnum; i++) {
  		if (gelf_getphdr(elf, i, &phdr) == NULL)
  			return -1;
  		if (phdr.p_type != PT_LOAD)
  			continue;
  		if (exe) {
  			if (!(phdr.p_flags & PF_X))
  				continue;
  		} else {
  			if (!(phdr.p_flags & PF_R))
  				continue;
  		}
  		sz = min(phdr.p_memsz, phdr.p_filesz);
  		if (!sz)
  			continue;
  		err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
  		if (err)
  			return err;
  	}
  	return 0;
  }
  
  int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
  		    bool *is_64_bit)
  {
  	int err;
  	Elf *elf;
  
  	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
  	if (elf == NULL)
  		return -1;
  
  	if (is_64_bit)
  		*is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
  
  	err = elf_read_maps(elf, exe, mapfn, data);
  
  	elf_end(elf);
  	return err;
  }
  
  enum dso_type dso__type_fd(int fd)
  {
  	enum dso_type dso_type = DSO__TYPE_UNKNOWN;
  	GElf_Ehdr ehdr;
  	Elf_Kind ek;
  	Elf *elf;
  
  	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
  	if (elf == NULL)
  		goto out;
  
  	ek = elf_kind(elf);
  	if (ek != ELF_K_ELF)
  		goto out_end;
  
  	if (gelf_getclass(elf) == ELFCLASS64) {
  		dso_type = DSO__TYPE_64BIT;
  		goto out_end;
  	}
  
  	if (gelf_getehdr(elf, &ehdr) == NULL)
  		goto out_end;
  
  	if (ehdr.e_machine == EM_X86_64)
  		dso_type = DSO__TYPE_X32BIT;
  	else
  		dso_type = DSO__TYPE_32BIT;
  out_end:
  	elf_end(elf);
  out:
  	return dso_type;
  }
  
  static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
  {
  	ssize_t r;
  	size_t n;
  	int err = -1;
  	char *buf = malloc(page_size);
  
  	if (buf == NULL)
  		return -1;
  
  	if (lseek(to, to_offs, SEEK_SET) != to_offs)
  		goto out;
  
  	if (lseek(from, from_offs, SEEK_SET) != from_offs)
  		goto out;
  
  	while (len) {
  		n = page_size;
  		if (len < n)
  			n = len;
  		/* Use read because mmap won't work on proc files */
  		r = read(from, buf, n);
  		if (r < 0)
  			goto out;
  		if (!r)
  			break;
  		n = r;
  		r = write(to, buf, n);
  		if (r < 0)
  			goto out;
  		if ((size_t)r != n)
  			goto out;
  		len -= n;
  	}
  
  	err = 0;
  out:
  	free(buf);
  	return err;
  }
  
  struct kcore {
  	int fd;
  	int elfclass;
  	Elf *elf;
  	GElf_Ehdr ehdr;
  };
  
  static int kcore__open(struct kcore *kcore, const char *filename)
  {
  	GElf_Ehdr *ehdr;
  
  	kcore->fd = open(filename, O_RDONLY);
  	if (kcore->fd == -1)
  		return -1;
  
  	kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
  	if (!kcore->elf)
  		goto out_close;
  
  	kcore->elfclass = gelf_getclass(kcore->elf);
  	if (kcore->elfclass == ELFCLASSNONE)
  		goto out_end;
  
  	ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
  	if (!ehdr)
  		goto out_end;
  
  	return 0;
  
  out_end:
  	elf_end(kcore->elf);
  out_close:
  	close(kcore->fd);
  	return -1;
  }
  
  static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
  		       bool temp)
  {
  	kcore->elfclass = elfclass;
  
  	if (temp)
  		kcore->fd = mkstemp(filename);
  	else
  		kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
  	if (kcore->fd == -1)
  		return -1;
  
  	kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
  	if (!kcore->elf)
  		goto out_close;
  
  	if (!gelf_newehdr(kcore->elf, elfclass))
  		goto out_end;
  
  	memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
  
  	return 0;
  
  out_end:
  	elf_end(kcore->elf);
  out_close:
  	close(kcore->fd);
  	unlink(filename);
  	return -1;
  }
  
  static void kcore__close(struct kcore *kcore)
  {
  	elf_end(kcore->elf);
  	close(kcore->fd);
  }
  
  static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
  {
  	GElf_Ehdr *ehdr = &to->ehdr;
  	GElf_Ehdr *kehdr = &from->ehdr;
  
  	memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
  	ehdr->e_type      = kehdr->e_type;
  	ehdr->e_machine   = kehdr->e_machine;
  	ehdr->e_version   = kehdr->e_version;
  	ehdr->e_entry     = 0;
  	ehdr->e_shoff     = 0;
  	ehdr->e_flags     = kehdr->e_flags;
  	ehdr->e_phnum     = count;
  	ehdr->e_shentsize = 0;
  	ehdr->e_shnum     = 0;
  	ehdr->e_shstrndx  = 0;
  
  	if (from->elfclass == ELFCLASS32) {
  		ehdr->e_phoff     = sizeof(Elf32_Ehdr);
  		ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
  		ehdr->e_phentsize = sizeof(Elf32_Phdr);
  	} else {
  		ehdr->e_phoff     = sizeof(Elf64_Ehdr);
  		ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
  		ehdr->e_phentsize = sizeof(Elf64_Phdr);
  	}
  
  	if (!gelf_update_ehdr(to->elf, ehdr))
  		return -1;
  
  	if (!gelf_newphdr(to->elf, count))
  		return -1;
  
  	return 0;
  }
  
  static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
  			   u64 addr, u64 len)
  {
  	GElf_Phdr phdr = {
  		.p_type		= PT_LOAD,
  		.p_flags	= PF_R | PF_W | PF_X,
  		.p_offset	= offset,
  		.p_vaddr	= addr,
  		.p_paddr	= 0,
  		.p_filesz	= len,
  		.p_memsz	= len,
  		.p_align	= page_size,
  	};
  
  	if (!gelf_update_phdr(kcore->elf, idx, &phdr))
  		return -1;
  
  	return 0;
  }
  
  static off_t kcore__write(struct kcore *kcore)
  {
  	return elf_update(kcore->elf, ELF_C_WRITE);
  }
  
  struct phdr_data {
  	off_t offset;
  	off_t rel;
  	u64 addr;
  	u64 len;
  	struct list_head node;
  	struct phdr_data *remaps;
  };
  
  struct sym_data {
  	u64 addr;
  	struct list_head node;
  };
  
  struct kcore_copy_info {
  	u64 stext;
  	u64 etext;
  	u64 first_symbol;
  	u64 last_symbol;
  	u64 first_module;
  	u64 last_module_symbol;
  	size_t phnum;
  	struct list_head phdrs;
  	struct list_head syms;
  };
  
  #define kcore_copy__for_each_phdr(k, p) \
  	list_for_each_entry((p), &(k)->phdrs, node)
  
  static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
  {
  	struct phdr_data *p = zalloc(sizeof(*p));
  
  	if (p) {
  		p->addr   = addr;
  		p->len    = len;
  		p->offset = offset;
  	}
  
  	return p;
  }
  
  static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
  						 u64 addr, u64 len,
  						 off_t offset)
  {
  	struct phdr_data *p = phdr_data__new(addr, len, offset);
  
  	if (p)
  		list_add_tail(&p->node, &kci->phdrs);
  
  	return p;
  }
  
  static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
  {
  	struct phdr_data *p, *tmp;
  
  	list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
  		list_del_init(&p->node);
  		free(p);
  	}
  }
  
  static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
  					    u64 addr)
  {
  	struct sym_data *s = zalloc(sizeof(*s));
  
  	if (s) {
  		s->addr = addr;
  		list_add_tail(&s->node, &kci->syms);
  	}
  
  	return s;
  }
  
  static void kcore_copy__free_syms(struct kcore_copy_info *kci)
  {
  	struct sym_data *s, *tmp;
  
  	list_for_each_entry_safe(s, tmp, &kci->syms, node) {
  		list_del_init(&s->node);
  		free(s);
  	}
  }
  
  static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
  					u64 start)
  {
  	struct kcore_copy_info *kci = arg;
  
  	if (!kallsyms__is_function(type))
  		return 0;
  
  	if (strchr(name, '[')) {
  		if (start > kci->last_module_symbol)
  			kci->last_module_symbol = start;
  		return 0;
  	}
  
  	if (!kci->first_symbol || start < kci->first_symbol)
  		kci->first_symbol = start;
  
  	if (!kci->last_symbol || start > kci->last_symbol)
  		kci->last_symbol = start;
  
  	if (!strcmp(name, "_stext")) {
  		kci->stext = start;
  		return 0;
  	}
  
  	if (!strcmp(name, "_etext")) {
  		kci->etext = start;
  		return 0;
  	}
  
  	if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
  		return -1;
  
  	return 0;
  }
  
  static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
  				      const char *dir)
  {
  	char kallsyms_filename[PATH_MAX];
  
  	scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
  
  	if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
  		return -1;
  
  	if (kallsyms__parse(kallsyms_filename, kci,
  			    kcore_copy__process_kallsyms) < 0)
  		return -1;
  
  	return 0;
  }
  
  static int kcore_copy__process_modules(void *arg,
  				       const char *name __maybe_unused,
  				       u64 start, u64 size __maybe_unused)
  {
  	struct kcore_copy_info *kci = arg;
  
  	if (!kci->first_module || start < kci->first_module)
  		kci->first_module = start;
  
  	return 0;
  }
  
  static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
  				     const char *dir)
  {
  	char modules_filename[PATH_MAX];
  
  	scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
  
  	if (symbol__restricted_filename(modules_filename, "/proc/modules"))
  		return -1;
  
  	if (modules__parse(modules_filename, kci,
  			   kcore_copy__process_modules) < 0)
  		return -1;
  
  	return 0;
  }
  
  static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
  			   u64 pgoff, u64 s, u64 e)
  {
  	u64 len, offset;
  
  	if (s < start || s >= end)
  		return 0;
  
  	offset = (s - start) + pgoff;
  	len = e < end ? e - s : end - s;
  
  	return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
  }
  
  static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
  {
  	struct kcore_copy_info *kci = data;
  	u64 end = start + len;
  	struct sym_data *sdat;
  
  	if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
  		return -1;
  
  	if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
  			    kci->last_module_symbol))
  		return -1;
  
  	list_for_each_entry(sdat, &kci->syms, node) {
  		u64 s = round_down(sdat->addr, page_size);
  
  		if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
  			return -1;
  	}
  
  	return 0;
  }
  
  static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
  {
  	if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
  		return -1;
  
  	return 0;
  }
  
  static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
  {
  	struct phdr_data *p, *k = NULL;
  	u64 kend;
  
  	if (!kci->stext)
  		return;
  
  	/* Find phdr that corresponds to the kernel map (contains stext) */
  	kcore_copy__for_each_phdr(kci, p) {
  		u64 pend = p->addr + p->len - 1;
  
  		if (p->addr <= kci->stext && pend >= kci->stext) {
  			k = p;
  			break;
  		}
  	}
  
  	if (!k)
  		return;
  
  	kend = k->offset + k->len;
  
  	/* Find phdrs that remap the kernel */
  	kcore_copy__for_each_phdr(kci, p) {
  		u64 pend = p->offset + p->len;
  
  		if (p == k)
  			continue;
  
  		if (p->offset >= k->offset && pend <= kend)
  			p->remaps = k;
  	}
  }
  
  static void kcore_copy__layout(struct kcore_copy_info *kci)
  {
  	struct phdr_data *p;
  	off_t rel = 0;
  
  	kcore_copy__find_remaps(kci);
  
  	kcore_copy__for_each_phdr(kci, p) {
  		if (!p->remaps) {
  			p->rel = rel;
  			rel += p->len;
  		}
  		kci->phnum += 1;
  	}
  
  	kcore_copy__for_each_phdr(kci, p) {
  		struct phdr_data *k = p->remaps;
  
  		if (k)
  			p->rel = p->offset - k->offset + k->rel;
  	}
  }
  
  static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
  				 Elf *elf)
  {
  	if (kcore_copy__parse_kallsyms(kci, dir))
  		return -1;
  
  	if (kcore_copy__parse_modules(kci, dir))
  		return -1;
  
  	if (kci->stext)
  		kci->stext = round_down(kci->stext, page_size);
  	else
  		kci->stext = round_down(kci->first_symbol, page_size);
  
  	if (kci->etext) {
  		kci->etext = round_up(kci->etext, page_size);
  	} else if (kci->last_symbol) {
  		kci->etext = round_up(kci->last_symbol, page_size);
  		kci->etext += page_size;
  	}
  
  	kci->first_module = round_down(kci->first_module, page_size);
  
  	if (kci->last_module_symbol) {
  		kci->last_module_symbol = round_up(kci->last_module_symbol,
  						   page_size);
  		kci->last_module_symbol += page_size;
  	}
  
  	if (!kci->stext || !kci->etext)
  		return -1;
  
  	if (kci->first_module && !kci->last_module_symbol)
  		return -1;
  
  	if (kcore_copy__read_maps(kci, elf))
  		return -1;
  
  	kcore_copy__layout(kci);
  
  	return 0;
  }
  
  static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
  				 const char *name)
  {
  	char from_filename[PATH_MAX];
  	char to_filename[PATH_MAX];
  
  	scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
  	scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
  
  	return copyfile_mode(from_filename, to_filename, 0400);
  }
  
  static int kcore_copy__unlink(const char *dir, const char *name)
  {
  	char filename[PATH_MAX];
  
  	scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
  
  	return unlink(filename);
  }
  
  static int kcore_copy__compare_fds(int from, int to)
  {
  	char *buf_from;
  	char *buf_to;
  	ssize_t ret;
  	size_t len;
  	int err = -1;
  
  	buf_from = malloc(page_size);
  	buf_to = malloc(page_size);
  	if (!buf_from || !buf_to)
  		goto out;
  
  	while (1) {
  		/* Use read because mmap won't work on proc files */
  		ret = read(from, buf_from, page_size);
  		if (ret < 0)
  			goto out;
  
  		if (!ret)
  			break;
  
  		len = ret;
  
  		if (readn(to, buf_to, len) != (int)len)
  			goto out;
  
  		if (memcmp(buf_from, buf_to, len))
  			goto out;
  	}
  
  	err = 0;
  out:
  	free(buf_to);
  	free(buf_from);
  	return err;
  }
  
  static int kcore_copy__compare_files(const char *from_filename,
  				     const char *to_filename)
  {
  	int from, to, err = -1;
  
  	from = open(from_filename, O_RDONLY);
  	if (from < 0)
  		return -1;
  
  	to = open(to_filename, O_RDONLY);
  	if (to < 0)
  		goto out_close_from;
  
  	err = kcore_copy__compare_fds(from, to);
  
  	close(to);
  out_close_from:
  	close(from);
  	return err;
  }
  
  static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
  				    const char *name)
  {
  	char from_filename[PATH_MAX];
  	char to_filename[PATH_MAX];
  
  	scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
  	scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
  
  	return kcore_copy__compare_files(from_filename, to_filename);
  }
  
  /**
   * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
   * @from_dir: from directory
   * @to_dir: to directory
   *
   * This function copies kallsyms, modules and kcore files from one directory to
   * another.  kallsyms and modules are copied entirely.  Only code segments are
   * copied from kcore.  It is assumed that two segments suffice: one for the
   * kernel proper and one for all the modules.  The code segments are determined
   * from kallsyms and modules files.  The kernel map starts at _stext or the
   * lowest function symbol, and ends at _etext or the highest function symbol.
   * The module map starts at the lowest module address and ends at the highest
   * module symbol.  Start addresses are rounded down to the nearest page.  End
   * addresses are rounded up to the nearest page.  An extra page is added to the
   * highest kernel symbol and highest module symbol to, hopefully, encompass that
   * symbol too.  Because it contains only code sections, the resulting kcore is
   * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
   * is not the same for the kernel map and the modules map.  That happens because
   * the data is copied adjacently whereas the original kcore has gaps.  Finally,
   * kallsyms and modules files are compared with their copies to check that
   * modules have not been loaded or unloaded while the copies were taking place.
   *
   * Return: %0 on success, %-1 on failure.
   */
  int kcore_copy(const char *from_dir, const char *to_dir)
  {
  	struct kcore kcore;
  	struct kcore extract;
  	int idx = 0, err = -1;
  	off_t offset, sz;
  	struct kcore_copy_info kci = { .stext = 0, };
  	char kcore_filename[PATH_MAX];
  	char extract_filename[PATH_MAX];
  	struct phdr_data *p;
  
  	INIT_LIST_HEAD(&kci.phdrs);
  	INIT_LIST_HEAD(&kci.syms);
  
  	if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
  		return -1;
  
  	if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
  		goto out_unlink_kallsyms;
  
  	scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
  	scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
  
  	if (kcore__open(&kcore, kcore_filename))
  		goto out_unlink_modules;
  
  	if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
  		goto out_kcore_close;
  
  	if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
  		goto out_kcore_close;
  
  	if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
  		goto out_extract_close;
  
  	offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
  		 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
  	offset = round_up(offset, page_size);
  
  	kcore_copy__for_each_phdr(&kci, p) {
  		off_t offs = p->rel + offset;
  
  		if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
  			goto out_extract_close;
  	}
  
  	sz = kcore__write(&extract);
  	if (sz < 0 || sz > offset)
  		goto out_extract_close;
  
  	kcore_copy__for_each_phdr(&kci, p) {
  		off_t offs = p->rel + offset;
  
  		if (p->remaps)
  			continue;
  		if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
  			goto out_extract_close;
  	}
  
  	if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
  		goto out_extract_close;
  
  	if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
  		goto out_extract_close;
  
  	err = 0;
  
  out_extract_close:
  	kcore__close(&extract);
  	if (err)
  		unlink(extract_filename);
  out_kcore_close:
  	kcore__close(&kcore);
  out_unlink_modules:
  	if (err)
  		kcore_copy__unlink(to_dir, "modules");
  out_unlink_kallsyms:
  	if (err)
  		kcore_copy__unlink(to_dir, "kallsyms");
  
  	kcore_copy__free_phdrs(&kci);
  	kcore_copy__free_syms(&kci);
  
  	return err;
  }
  
  int kcore_extract__create(struct kcore_extract *kce)
  {
  	struct kcore kcore;
  	struct kcore extract;
  	size_t count = 1;
  	int idx = 0, err = -1;
  	off_t offset = page_size, sz;
  
  	if (kcore__open(&kcore, kce->kcore_filename))
  		return -1;
  
  	strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
  	if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
  		goto out_kcore_close;
  
  	if (kcore__copy_hdr(&kcore, &extract, count))
  		goto out_extract_close;
  
  	if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
  		goto out_extract_close;
  
  	sz = kcore__write(&extract);
  	if (sz < 0 || sz > offset)
  		goto out_extract_close;
  
  	if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
  		goto out_extract_close;
  
  	err = 0;
  
  out_extract_close:
  	kcore__close(&extract);
  	if (err)
  		unlink(kce->extract_filename);
  out_kcore_close:
  	kcore__close(&kcore);
  
  	return err;
  }
  
  void kcore_extract__delete(struct kcore_extract *kce)
  {
  	unlink(kce->extract_filename);
  }
  
  #ifdef HAVE_GELF_GETNOTE_SUPPORT
  
  static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
  {
  	if (!base_off)
  		return;
  
  	if (tmp->bit32)
  		tmp->addr.a32[SDT_NOTE_IDX_LOC] =
  			tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
  			tmp->addr.a32[SDT_NOTE_IDX_BASE];
  	else
  		tmp->addr.a64[SDT_NOTE_IDX_LOC] =
  			tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
  			tmp->addr.a64[SDT_NOTE_IDX_BASE];
  }
  
  static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
  			      GElf_Addr base_off)
  {
  	if (!base_off)
  		return;
  
  	if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
  		tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
  	else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
  		tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
  }
  
  /**
   * populate_sdt_note : Parse raw data and identify SDT note
   * @elf: elf of the opened file
   * @data: raw data of a section with description offset applied
   * @len: note description size
   * @type: type of the note
   * @sdt_notes: List to add the SDT note
   *
   * Responsible for parsing the @data in section .note.stapsdt in @elf and
   * if its an SDT note, it appends to @sdt_notes list.
   */
  static int populate_sdt_note(Elf **elf, const char *data, size_t len,
  			     struct list_head *sdt_notes)
  {
  	const char *provider, *name, *args;
  	struct sdt_note *tmp = NULL;
  	GElf_Ehdr ehdr;
  	GElf_Shdr shdr;
  	int ret = -EINVAL;
  
  	union {
  		Elf64_Addr a64[NR_ADDR];
  		Elf32_Addr a32[NR_ADDR];
  	} buf;
  
  	Elf_Data dst = {
  		.d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
  		.d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
  		.d_off = 0, .d_align = 0
  	};
  	Elf_Data src = {
  		.d_buf = (void *) data, .d_type = ELF_T_ADDR,
  		.d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
  		.d_align = 0
  	};
  
  	tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
  	if (!tmp) {
  		ret = -ENOMEM;
  		goto out_err;
  	}
  
  	INIT_LIST_HEAD(&tmp->note_list);
  
  	if (len < dst.d_size + 3)
  		goto out_free_note;
  
  	/* Translation from file representation to memory representation */
  	if (gelf_xlatetom(*elf, &dst, &src,
  			  elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
  		pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
  		goto out_free_note;
  	}
  
  	/* Populate the fields of sdt_note */
  	provider = data + dst.d_size;
  
  	name = (const char *)memchr(provider, '\0', data + len - provider);
  	if (name++ == NULL)
  		goto out_free_note;
  
  	tmp->provider = strdup(provider);
  	if (!tmp->provider) {
  		ret = -ENOMEM;
  		goto out_free_note;
  	}
  	tmp->name = strdup(name);
  	if (!tmp->name) {
  		ret = -ENOMEM;
  		goto out_free_prov;
  	}
  
  	args = memchr(name, '\0', data + len - name);
  
  	/*
  	 * There is no argument if:
  	 * - We reached the end of the note;
  	 * - There is not enough room to hold a potential string;
  	 * - The argument string is empty or just contains ':'.
  	 */
  	if (args == NULL || data + len - args < 2 ||
  		args[1] == ':' || args[1] == '\0')
  		tmp->args = NULL;
  	else {
  		tmp->args = strdup(++args);
  		if (!tmp->args) {
  			ret = -ENOMEM;
  			goto out_free_name;
  		}
  	}
  
  	if (gelf_getclass(*elf) == ELFCLASS32) {
  		memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
  		tmp->bit32 = true;
  	} else {
  		memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
  		tmp->bit32 = false;
  	}
  
  	if (!gelf_getehdr(*elf, &ehdr)) {
  		pr_debug("%s : cannot get elf header.\n", __func__);
  		ret = -EBADF;
  		goto out_free_args;
  	}
  
  	/* Adjust the prelink effect :
  	 * Find out the .stapsdt.base section.
  	 * This scn will help us to handle prelinking (if present).
  	 * Compare the retrieved file offset of the base section with the
  	 * base address in the description of the SDT note. If its different,
  	 * then accordingly, adjust the note location.
  	 */
  	if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
  		sdt_adjust_loc(tmp, shdr.sh_offset);
  
  	/* Adjust reference counter offset */
  	if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
  		sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
  
  	list_add_tail(&tmp->note_list, sdt_notes);
  	return 0;
  
  out_free_args:
  	zfree(&tmp->args);
  out_free_name:
  	zfree(&tmp->name);
  out_free_prov:
  	zfree(&tmp->provider);
  out_free_note:
  	free(tmp);
  out_err:
  	return ret;
  }
  
  /**
   * construct_sdt_notes_list : constructs a list of SDT notes
   * @elf : elf to look into
   * @sdt_notes : empty list_head
   *
   * Scans the sections in 'elf' for the section
   * .note.stapsdt. It, then calls populate_sdt_note to find
   * out the SDT events and populates the 'sdt_notes'.
   */
  static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
  {
  	GElf_Ehdr ehdr;
  	Elf_Scn *scn = NULL;
  	Elf_Data *data;
  	GElf_Shdr shdr;
  	size_t shstrndx, next;
  	GElf_Nhdr nhdr;
  	size_t name_off, desc_off, offset;
  	int ret = 0;
  
  	if (gelf_getehdr(elf, &ehdr) == NULL) {
  		ret = -EBADF;
  		goto out_ret;
  	}
  	if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
  		ret = -EBADF;
  		goto out_ret;
  	}
  
  	/* Look for the required section */
  	scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
  	if (!scn) {
  		ret = -ENOENT;
  		goto out_ret;
  	}
  
  	if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
  		ret = -ENOENT;
  		goto out_ret;
  	}
  
  	data = elf_getdata(scn, NULL);
  
  	/* Get the SDT notes */
  	for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
  					      &desc_off)) > 0; offset = next) {
  		if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
  		    !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
  			    sizeof(SDT_NOTE_NAME))) {
  			/* Check the type of the note */
  			if (nhdr.n_type != SDT_NOTE_TYPE)
  				goto out_ret;
  
  			ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
  						nhdr.n_descsz, sdt_notes);
  			if (ret < 0)
  				goto out_ret;
  		}
  	}
  	if (list_empty(sdt_notes))
  		ret = -ENOENT;
  
  out_ret:
  	return ret;
  }
  
  /**
   * get_sdt_note_list : Wrapper to construct a list of sdt notes
   * @head : empty list_head
   * @target : file to find SDT notes from
   *
   * This opens the file, initializes
   * the ELF and then calls construct_sdt_notes_list.
   */
  int get_sdt_note_list(struct list_head *head, const char *target)
  {
  	Elf *elf;
  	int fd, ret;
  
  	fd = open(target, O_RDONLY);
  	if (fd < 0)
  		return -EBADF;
  
  	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
  	if (!elf) {
  		ret = -EBADF;
  		goto out_close;
  	}
  	ret = construct_sdt_notes_list(elf, head);
  	elf_end(elf);
  out_close:
  	close(fd);
  	return ret;
  }
  
  /**
   * cleanup_sdt_note_list : free the sdt notes' list
   * @sdt_notes: sdt notes' list
   *
   * Free up the SDT notes in @sdt_notes.
   * Returns the number of SDT notes free'd.
   */
  int cleanup_sdt_note_list(struct list_head *sdt_notes)
  {
  	struct sdt_note *tmp, *pos;
  	int nr_free = 0;
  
  	list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
  		list_del_init(&pos->note_list);
  		zfree(&pos->name);
  		zfree(&pos->provider);
  		free(pos);
  		nr_free++;
  	}
  	return nr_free;
  }
  
  /**
   * sdt_notes__get_count: Counts the number of sdt events
   * @start: list_head to sdt_notes list
   *
   * Returns the number of SDT notes in a list
   */
  int sdt_notes__get_count(struct list_head *start)
  {
  	struct sdt_note *sdt_ptr;
  	int count = 0;
  
  	list_for_each_entry(sdt_ptr, start, note_list)
  		count++;
  	return count;
  }
  #endif
  
  void symbol__elf_init(void)
  {
  	elf_version(EV_CURRENT);
  }
  