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TOMOYO Linux Cross Reference
Linux/tools/perf/util/symbol-elf.c

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

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