Merge tag 'trace-v4.19-rc8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rosted...
[muen/linux.git] / tools / perf / util / symbol-elf.c
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 typedef Elf64_Nhdr GElf_Nhdr;
23
24 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
25 extern char *cplus_demangle(const char *, int);
26
27 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
28 {
29         return cplus_demangle(c, i);
30 }
31 #else
32 #ifdef NO_DEMANGLE
33 static inline char *bfd_demangle(void __maybe_unused *v,
34                                  const char __maybe_unused *c,
35                                  int __maybe_unused i)
36 {
37         return NULL;
38 }
39 #else
40 #define PACKAGE 'perf'
41 #include <bfd.h>
42 #endif
43 #endif
44
45 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
46 static int elf_getphdrnum(Elf *elf, size_t *dst)
47 {
48         GElf_Ehdr gehdr;
49         GElf_Ehdr *ehdr;
50
51         ehdr = gelf_getehdr(elf, &gehdr);
52         if (!ehdr)
53                 return -1;
54
55         *dst = ehdr->e_phnum;
56
57         return 0;
58 }
59 #endif
60
61 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
62 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
63 {
64         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
65         return -1;
66 }
67 #endif
68
69 #ifndef NT_GNU_BUILD_ID
70 #define NT_GNU_BUILD_ID 3
71 #endif
72
73 /**
74  * elf_symtab__for_each_symbol - iterate thru all the symbols
75  *
76  * @syms: struct elf_symtab instance to iterate
77  * @idx: uint32_t idx
78  * @sym: GElf_Sym iterator
79  */
80 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
81         for (idx = 0, gelf_getsym(syms, idx, &sym);\
82              idx < nr_syms; \
83              idx++, gelf_getsym(syms, idx, &sym))
84
85 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
86 {
87         return GELF_ST_TYPE(sym->st_info);
88 }
89
90 #ifndef STT_GNU_IFUNC
91 #define STT_GNU_IFUNC 10
92 #endif
93
94 static inline int elf_sym__is_function(const GElf_Sym *sym)
95 {
96         return (elf_sym__type(sym) == STT_FUNC ||
97                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
98                sym->st_name != 0 &&
99                sym->st_shndx != SHN_UNDEF;
100 }
101
102 static inline bool elf_sym__is_object(const GElf_Sym *sym)
103 {
104         return elf_sym__type(sym) == STT_OBJECT &&
105                 sym->st_name != 0 &&
106                 sym->st_shndx != SHN_UNDEF;
107 }
108
109 static inline int elf_sym__is_label(const GElf_Sym *sym)
110 {
111         return elf_sym__type(sym) == STT_NOTYPE &&
112                 sym->st_name != 0 &&
113                 sym->st_shndx != SHN_UNDEF &&
114                 sym->st_shndx != SHN_ABS;
115 }
116
117 static bool elf_sym__filter(GElf_Sym *sym)
118 {
119         return elf_sym__is_function(sym) || elf_sym__is_object(sym);
120 }
121
122 static inline const char *elf_sym__name(const GElf_Sym *sym,
123                                         const Elf_Data *symstrs)
124 {
125         return symstrs->d_buf + sym->st_name;
126 }
127
128 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
129                                         const Elf_Data *secstrs)
130 {
131         return secstrs->d_buf + shdr->sh_name;
132 }
133
134 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
135                                         const Elf_Data *secstrs)
136 {
137         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
138 }
139
140 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
141                                     const Elf_Data *secstrs)
142 {
143         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
144 }
145
146 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
147 {
148         return elf_sec__is_text(shdr, secstrs) || 
149                elf_sec__is_data(shdr, secstrs);
150 }
151
152 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
153 {
154         Elf_Scn *sec = NULL;
155         GElf_Shdr shdr;
156         size_t cnt = 1;
157
158         while ((sec = elf_nextscn(elf, sec)) != NULL) {
159                 gelf_getshdr(sec, &shdr);
160
161                 if ((addr >= shdr.sh_addr) &&
162                     (addr < (shdr.sh_addr + shdr.sh_size)))
163                         return cnt;
164
165                 ++cnt;
166         }
167
168         return -1;
169 }
170
171 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
172                              GElf_Shdr *shp, const char *name, size_t *idx)
173 {
174         Elf_Scn *sec = NULL;
175         size_t cnt = 1;
176
177         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
178         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
179                 return NULL;
180
181         while ((sec = elf_nextscn(elf, sec)) != NULL) {
182                 char *str;
183
184                 gelf_getshdr(sec, shp);
185                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
186                 if (str && !strcmp(name, str)) {
187                         if (idx)
188                                 *idx = cnt;
189                         return sec;
190                 }
191                 ++cnt;
192         }
193
194         return NULL;
195 }
196
197 static bool want_demangle(bool is_kernel_sym)
198 {
199         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
200 }
201
202 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
203 {
204         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
205         char *demangled = NULL;
206
207         /*
208          * We need to figure out if the object was created from C++ sources
209          * DWARF DW_compile_unit has this, but we don't always have access
210          * to it...
211          */
212         if (!want_demangle(dso->kernel || kmodule))
213             return demangled;
214
215         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
216         if (demangled == NULL)
217                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
218         else if (rust_is_mangled(demangled))
219                 /*
220                     * Input to Rust demangling is the BFD-demangled
221                     * name which it Rust-demangles in place.
222                     */
223                 rust_demangle_sym(demangled);
224
225         return demangled;
226 }
227
228 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
229         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
230              idx < nr_entries; \
231              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
232
233 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
234         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
235              idx < nr_entries; \
236              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
237
238 /*
239  * We need to check if we have a .dynsym, so that we can handle the
240  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
241  * .dynsym or .symtab).
242  * And always look at the original dso, not at debuginfo packages, that
243  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
244  */
245 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
246 {
247         uint32_t nr_rel_entries, idx;
248         GElf_Sym sym;
249         u64 plt_offset, plt_header_size, plt_entry_size;
250         GElf_Shdr shdr_plt;
251         struct symbol *f;
252         GElf_Shdr shdr_rel_plt, shdr_dynsym;
253         Elf_Data *reldata, *syms, *symstrs;
254         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
255         size_t dynsym_idx;
256         GElf_Ehdr ehdr;
257         char sympltname[1024];
258         Elf *elf;
259         int nr = 0, symidx, err = 0;
260
261         if (!ss->dynsym)
262                 return 0;
263
264         elf = ss->elf;
265         ehdr = ss->ehdr;
266
267         scn_dynsym = ss->dynsym;
268         shdr_dynsym = ss->dynshdr;
269         dynsym_idx = ss->dynsym_idx;
270
271         if (scn_dynsym == NULL)
272                 goto out_elf_end;
273
274         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
275                                           ".rela.plt", NULL);
276         if (scn_plt_rel == NULL) {
277                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
278                                                   ".rel.plt", NULL);
279                 if (scn_plt_rel == NULL)
280                         goto out_elf_end;
281         }
282
283         err = -1;
284
285         if (shdr_rel_plt.sh_link != dynsym_idx)
286                 goto out_elf_end;
287
288         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
289                 goto out_elf_end;
290
291         /*
292          * Fetch the relocation section to find the idxes to the GOT
293          * and the symbols in the .dynsym they refer to.
294          */
295         reldata = elf_getdata(scn_plt_rel, NULL);
296         if (reldata == NULL)
297                 goto out_elf_end;
298
299         syms = elf_getdata(scn_dynsym, NULL);
300         if (syms == NULL)
301                 goto out_elf_end;
302
303         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
304         if (scn_symstrs == NULL)
305                 goto out_elf_end;
306
307         symstrs = elf_getdata(scn_symstrs, NULL);
308         if (symstrs == NULL)
309                 goto out_elf_end;
310
311         if (symstrs->d_size == 0)
312                 goto out_elf_end;
313
314         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
315         plt_offset = shdr_plt.sh_offset;
316         switch (ehdr.e_machine) {
317                 case EM_ARM:
318                         plt_header_size = 20;
319                         plt_entry_size = 12;
320                         break;
321
322                 case EM_AARCH64:
323                         plt_header_size = 32;
324                         plt_entry_size = 16;
325                         break;
326
327                 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/sparc/xtensa need to be checked */
328                         plt_header_size = shdr_plt.sh_entsize;
329                         plt_entry_size = shdr_plt.sh_entsize;
330                         break;
331         }
332         plt_offset += plt_header_size;
333
334         if (shdr_rel_plt.sh_type == SHT_RELA) {
335                 GElf_Rela pos_mem, *pos;
336
337                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
338                                            nr_rel_entries) {
339                         const char *elf_name = NULL;
340                         char *demangled = NULL;
341                         symidx = GELF_R_SYM(pos->r_info);
342                         gelf_getsym(syms, symidx, &sym);
343
344                         elf_name = elf_sym__name(&sym, symstrs);
345                         demangled = demangle_sym(dso, 0, elf_name);
346                         if (demangled != NULL)
347                                 elf_name = demangled;
348                         snprintf(sympltname, sizeof(sympltname),
349                                  "%s@plt", elf_name);
350                         free(demangled);
351
352                         f = symbol__new(plt_offset, plt_entry_size,
353                                         STB_GLOBAL, STT_FUNC, sympltname);
354                         if (!f)
355                                 goto out_elf_end;
356
357                         plt_offset += plt_entry_size;
358                         symbols__insert(&dso->symbols, f);
359                         ++nr;
360                 }
361         } else if (shdr_rel_plt.sh_type == SHT_REL) {
362                 GElf_Rel pos_mem, *pos;
363                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
364                                           nr_rel_entries) {
365                         const char *elf_name = NULL;
366                         char *demangled = NULL;
367                         symidx = GELF_R_SYM(pos->r_info);
368                         gelf_getsym(syms, symidx, &sym);
369
370                         elf_name = elf_sym__name(&sym, symstrs);
371                         demangled = demangle_sym(dso, 0, elf_name);
372                         if (demangled != NULL)
373                                 elf_name = demangled;
374                         snprintf(sympltname, sizeof(sympltname),
375                                  "%s@plt", elf_name);
376                         free(demangled);
377
378                         f = symbol__new(plt_offset, plt_entry_size,
379                                         STB_GLOBAL, STT_FUNC, sympltname);
380                         if (!f)
381                                 goto out_elf_end;
382
383                         plt_offset += plt_entry_size;
384                         symbols__insert(&dso->symbols, f);
385                         ++nr;
386                 }
387         }
388
389         err = 0;
390 out_elf_end:
391         if (err == 0)
392                 return nr;
393         pr_debug("%s: problems reading %s PLT info.\n",
394                  __func__, dso->long_name);
395         return 0;
396 }
397
398 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
399 {
400         return demangle_sym(dso, kmodule, elf_name);
401 }
402
403 /*
404  * Align offset to 4 bytes as needed for note name and descriptor data.
405  */
406 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
407
408 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
409 {
410         int err = -1;
411         GElf_Ehdr ehdr;
412         GElf_Shdr shdr;
413         Elf_Data *data;
414         Elf_Scn *sec;
415         Elf_Kind ek;
416         void *ptr;
417
418         if (size < BUILD_ID_SIZE)
419                 goto out;
420
421         ek = elf_kind(elf);
422         if (ek != ELF_K_ELF)
423                 goto out;
424
425         if (gelf_getehdr(elf, &ehdr) == NULL) {
426                 pr_err("%s: cannot get elf header.\n", __func__);
427                 goto out;
428         }
429
430         /*
431          * Check following sections for notes:
432          *   '.note.gnu.build-id'
433          *   '.notes'
434          *   '.note' (VDSO specific)
435          */
436         do {
437                 sec = elf_section_by_name(elf, &ehdr, &shdr,
438                                           ".note.gnu.build-id", NULL);
439                 if (sec)
440                         break;
441
442                 sec = elf_section_by_name(elf, &ehdr, &shdr,
443                                           ".notes", NULL);
444                 if (sec)
445                         break;
446
447                 sec = elf_section_by_name(elf, &ehdr, &shdr,
448                                           ".note", NULL);
449                 if (sec)
450                         break;
451
452                 return err;
453
454         } while (0);
455
456         data = elf_getdata(sec, NULL);
457         if (data == NULL)
458                 goto out;
459
460         ptr = data->d_buf;
461         while (ptr < (data->d_buf + data->d_size)) {
462                 GElf_Nhdr *nhdr = ptr;
463                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
464                        descsz = NOTE_ALIGN(nhdr->n_descsz);
465                 const char *name;
466
467                 ptr += sizeof(*nhdr);
468                 name = ptr;
469                 ptr += namesz;
470                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
471                     nhdr->n_namesz == sizeof("GNU")) {
472                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
473                                 size_t sz = min(size, descsz);
474                                 memcpy(bf, ptr, sz);
475                                 memset(bf + sz, 0, size - sz);
476                                 err = descsz;
477                                 break;
478                         }
479                 }
480                 ptr += descsz;
481         }
482
483 out:
484         return err;
485 }
486
487 int filename__read_build_id(const char *filename, void *bf, size_t size)
488 {
489         int fd, err = -1;
490         Elf *elf;
491
492         if (size < BUILD_ID_SIZE)
493                 goto out;
494
495         fd = open(filename, O_RDONLY);
496         if (fd < 0)
497                 goto out;
498
499         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
500         if (elf == NULL) {
501                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
502                 goto out_close;
503         }
504
505         err = elf_read_build_id(elf, bf, size);
506
507         elf_end(elf);
508 out_close:
509         close(fd);
510 out:
511         return err;
512 }
513
514 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
515 {
516         int fd, err = -1;
517
518         if (size < BUILD_ID_SIZE)
519                 goto out;
520
521         fd = open(filename, O_RDONLY);
522         if (fd < 0)
523                 goto out;
524
525         while (1) {
526                 char bf[BUFSIZ];
527                 GElf_Nhdr nhdr;
528                 size_t namesz, descsz;
529
530                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
531                         break;
532
533                 namesz = NOTE_ALIGN(nhdr.n_namesz);
534                 descsz = NOTE_ALIGN(nhdr.n_descsz);
535                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
536                     nhdr.n_namesz == sizeof("GNU")) {
537                         if (read(fd, bf, namesz) != (ssize_t)namesz)
538                                 break;
539                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
540                                 size_t sz = min(descsz, size);
541                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
542                                         memset(build_id + sz, 0, size - sz);
543                                         err = 0;
544                                         break;
545                                 }
546                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
547                                 break;
548                 } else {
549                         int n = namesz + descsz;
550
551                         if (n > (int)sizeof(bf)) {
552                                 n = sizeof(bf);
553                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
554                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
555                         }
556                         if (read(fd, bf, n) != n)
557                                 break;
558                 }
559         }
560         close(fd);
561 out:
562         return err;
563 }
564
565 int filename__read_debuglink(const char *filename, char *debuglink,
566                              size_t size)
567 {
568         int fd, err = -1;
569         Elf *elf;
570         GElf_Ehdr ehdr;
571         GElf_Shdr shdr;
572         Elf_Data *data;
573         Elf_Scn *sec;
574         Elf_Kind ek;
575
576         fd = open(filename, O_RDONLY);
577         if (fd < 0)
578                 goto out;
579
580         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
581         if (elf == NULL) {
582                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
583                 goto out_close;
584         }
585
586         ek = elf_kind(elf);
587         if (ek != ELF_K_ELF)
588                 goto out_elf_end;
589
590         if (gelf_getehdr(elf, &ehdr) == NULL) {
591                 pr_err("%s: cannot get elf header.\n", __func__);
592                 goto out_elf_end;
593         }
594
595         sec = elf_section_by_name(elf, &ehdr, &shdr,
596                                   ".gnu_debuglink", NULL);
597         if (sec == NULL)
598                 goto out_elf_end;
599
600         data = elf_getdata(sec, NULL);
601         if (data == NULL)
602                 goto out_elf_end;
603
604         /* the start of this section is a zero-terminated string */
605         strncpy(debuglink, data->d_buf, size);
606
607         err = 0;
608
609 out_elf_end:
610         elf_end(elf);
611 out_close:
612         close(fd);
613 out:
614         return err;
615 }
616
617 static int dso__swap_init(struct dso *dso, unsigned char eidata)
618 {
619         static unsigned int const endian = 1;
620
621         dso->needs_swap = DSO_SWAP__NO;
622
623         switch (eidata) {
624         case ELFDATA2LSB:
625                 /* We are big endian, DSO is little endian. */
626                 if (*(unsigned char const *)&endian != 1)
627                         dso->needs_swap = DSO_SWAP__YES;
628                 break;
629
630         case ELFDATA2MSB:
631                 /* We are little endian, DSO is big endian. */
632                 if (*(unsigned char const *)&endian != 0)
633                         dso->needs_swap = DSO_SWAP__YES;
634                 break;
635
636         default:
637                 pr_err("unrecognized DSO data encoding %d\n", eidata);
638                 return -EINVAL;
639         }
640
641         return 0;
642 }
643
644 bool symsrc__possibly_runtime(struct symsrc *ss)
645 {
646         return ss->dynsym || ss->opdsec;
647 }
648
649 bool symsrc__has_symtab(struct symsrc *ss)
650 {
651         return ss->symtab != NULL;
652 }
653
654 void symsrc__destroy(struct symsrc *ss)
655 {
656         zfree(&ss->name);
657         elf_end(ss->elf);
658         close(ss->fd);
659 }
660
661 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
662 {
663         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
664 }
665
666 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
667                  enum dso_binary_type type)
668 {
669         int err = -1;
670         GElf_Ehdr ehdr;
671         Elf *elf;
672         int fd;
673
674         if (dso__needs_decompress(dso)) {
675                 fd = dso__decompress_kmodule_fd(dso, name);
676                 if (fd < 0)
677                         return -1;
678
679                 type = dso->symtab_type;
680         } else {
681                 fd = open(name, O_RDONLY);
682                 if (fd < 0) {
683                         dso->load_errno = errno;
684                         return -1;
685                 }
686         }
687
688         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
689         if (elf == NULL) {
690                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
691                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
692                 goto out_close;
693         }
694
695         if (gelf_getehdr(elf, &ehdr) == NULL) {
696                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
697                 pr_debug("%s: cannot get elf header.\n", __func__);
698                 goto out_elf_end;
699         }
700
701         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
702                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
703                 goto out_elf_end;
704         }
705
706         /* Always reject images with a mismatched build-id: */
707         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
708                 u8 build_id[BUILD_ID_SIZE];
709
710                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
711                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
712                         goto out_elf_end;
713                 }
714
715                 if (!dso__build_id_equal(dso, build_id)) {
716                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
717                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
718                         goto out_elf_end;
719                 }
720         }
721
722         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
723
724         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
725                         NULL);
726         if (ss->symshdr.sh_type != SHT_SYMTAB)
727                 ss->symtab = NULL;
728
729         ss->dynsym_idx = 0;
730         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
731                         &ss->dynsym_idx);
732         if (ss->dynshdr.sh_type != SHT_DYNSYM)
733                 ss->dynsym = NULL;
734
735         ss->opdidx = 0;
736         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
737                         &ss->opdidx);
738         if (ss->opdshdr.sh_type != SHT_PROGBITS)
739                 ss->opdsec = NULL;
740
741         if (dso->kernel == DSO_TYPE_USER)
742                 ss->adjust_symbols = true;
743         else
744                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
745
746         ss->name   = strdup(name);
747         if (!ss->name) {
748                 dso->load_errno = errno;
749                 goto out_elf_end;
750         }
751
752         ss->elf    = elf;
753         ss->fd     = fd;
754         ss->ehdr   = ehdr;
755         ss->type   = type;
756
757         return 0;
758
759 out_elf_end:
760         elf_end(elf);
761 out_close:
762         close(fd);
763         return err;
764 }
765
766 /**
767  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
768  * @kmap: kernel maps and relocation reference symbol
769  *
770  * This function returns %true if we are dealing with the kernel maps and the
771  * relocation reference symbol has not yet been found.  Otherwise %false is
772  * returned.
773  */
774 static bool ref_reloc_sym_not_found(struct kmap *kmap)
775 {
776         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
777                !kmap->ref_reloc_sym->unrelocated_addr;
778 }
779
780 /**
781  * ref_reloc - kernel relocation offset.
782  * @kmap: kernel maps and relocation reference symbol
783  *
784  * This function returns the offset of kernel addresses as determined by using
785  * the relocation reference symbol i.e. if the kernel has not been relocated
786  * then the return value is zero.
787  */
788 static u64 ref_reloc(struct kmap *kmap)
789 {
790         if (kmap && kmap->ref_reloc_sym &&
791             kmap->ref_reloc_sym->unrelocated_addr)
792                 return kmap->ref_reloc_sym->addr -
793                        kmap->ref_reloc_sym->unrelocated_addr;
794         return 0;
795 }
796
797 void __weak arch__sym_update(struct symbol *s __maybe_unused,
798                 GElf_Sym *sym __maybe_unused) { }
799
800 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
801                                       GElf_Sym *sym, GElf_Shdr *shdr,
802                                       struct map_groups *kmaps, struct kmap *kmap,
803                                       struct dso **curr_dsop, struct map **curr_mapp,
804                                       const char *section_name,
805                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
806 {
807         struct dso *curr_dso = *curr_dsop;
808         struct map *curr_map;
809         char dso_name[PATH_MAX];
810
811         /* Adjust symbol to map to file offset */
812         if (adjust_kernel_syms)
813                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
814
815         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
816                 return 0;
817
818         if (strcmp(section_name, ".text") == 0) {
819                 /*
820                  * The initial kernel mapping is based on
821                  * kallsyms and identity maps.  Overwrite it to
822                  * map to the kernel dso.
823                  */
824                 if (*remap_kernel && dso->kernel) {
825                         *remap_kernel = false;
826                         map->start = shdr->sh_addr + ref_reloc(kmap);
827                         map->end = map->start + shdr->sh_size;
828                         map->pgoff = shdr->sh_offset;
829                         map->map_ip = map__map_ip;
830                         map->unmap_ip = map__unmap_ip;
831                         /* Ensure maps are correctly ordered */
832                         if (kmaps) {
833                                 map__get(map);
834                                 map_groups__remove(kmaps, map);
835                                 map_groups__insert(kmaps, map);
836                                 map__put(map);
837                         }
838                 }
839
840                 /*
841                  * The initial module mapping is based on
842                  * /proc/modules mapped to offset zero.
843                  * Overwrite it to map to the module dso.
844                  */
845                 if (*remap_kernel && kmodule) {
846                         *remap_kernel = false;
847                         map->pgoff = shdr->sh_offset;
848                 }
849
850                 *curr_mapp = map;
851                 *curr_dsop = dso;
852                 return 0;
853         }
854
855         if (!kmap)
856                 return 0;
857
858         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
859
860         curr_map = map_groups__find_by_name(kmaps, dso_name);
861         if (curr_map == NULL) {
862                 u64 start = sym->st_value;
863
864                 if (kmodule)
865                         start += map->start + shdr->sh_offset;
866
867                 curr_dso = dso__new(dso_name);
868                 if (curr_dso == NULL)
869                         return -1;
870                 curr_dso->kernel = dso->kernel;
871                 curr_dso->long_name = dso->long_name;
872                 curr_dso->long_name_len = dso->long_name_len;
873                 curr_map = map__new2(start, curr_dso);
874                 dso__put(curr_dso);
875                 if (curr_map == NULL)
876                         return -1;
877
878                 if (adjust_kernel_syms) {
879                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
880                         curr_map->end    = curr_map->start + shdr->sh_size;
881                         curr_map->pgoff  = shdr->sh_offset;
882                 } else {
883                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
884                 }
885                 curr_dso->symtab_type = dso->symtab_type;
886                 map_groups__insert(kmaps, curr_map);
887                 /*
888                  * Add it before we drop the referece to curr_map, i.e. while
889                  * we still are sure to have a reference to this DSO via
890                  * *curr_map->dso.
891                  */
892                 dsos__add(&map->groups->machine->dsos, curr_dso);
893                 /* kmaps already got it */
894                 map__put(curr_map);
895                 dso__set_loaded(curr_dso);
896                 *curr_mapp = curr_map;
897                 *curr_dsop = curr_dso;
898         } else
899                 *curr_dsop = curr_map->dso;
900
901         return 0;
902 }
903
904 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
905                   struct symsrc *runtime_ss, int kmodule)
906 {
907         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
908         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
909         struct map *curr_map = map;
910         struct dso *curr_dso = dso;
911         Elf_Data *symstrs, *secstrs;
912         uint32_t nr_syms;
913         int err = -1;
914         uint32_t idx;
915         GElf_Ehdr ehdr;
916         GElf_Shdr shdr;
917         GElf_Shdr tshdr;
918         Elf_Data *syms, *opddata = NULL;
919         GElf_Sym sym;
920         Elf_Scn *sec, *sec_strndx;
921         Elf *elf;
922         int nr = 0;
923         bool remap_kernel = false, adjust_kernel_syms = false;
924
925         if (kmap && !kmaps)
926                 return -1;
927
928         dso->symtab_type = syms_ss->type;
929         dso->is_64_bit = syms_ss->is_64_bit;
930         dso->rel = syms_ss->ehdr.e_type == ET_REL;
931
932         /*
933          * Modules may already have symbols from kallsyms, but those symbols
934          * have the wrong values for the dso maps, so remove them.
935          */
936         if (kmodule && syms_ss->symtab)
937                 symbols__delete(&dso->symbols);
938
939         if (!syms_ss->symtab) {
940                 /*
941                  * If the vmlinux is stripped, fail so we will fall back
942                  * to using kallsyms. The vmlinux runtime symbols aren't
943                  * of much use.
944                  */
945                 if (dso->kernel)
946                         goto out_elf_end;
947
948                 syms_ss->symtab  = syms_ss->dynsym;
949                 syms_ss->symshdr = syms_ss->dynshdr;
950         }
951
952         elf = syms_ss->elf;
953         ehdr = syms_ss->ehdr;
954         sec = syms_ss->symtab;
955         shdr = syms_ss->symshdr;
956
957         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
958                                 ".text", NULL))
959                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
960
961         if (runtime_ss->opdsec)
962                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
963
964         syms = elf_getdata(sec, NULL);
965         if (syms == NULL)
966                 goto out_elf_end;
967
968         sec = elf_getscn(elf, shdr.sh_link);
969         if (sec == NULL)
970                 goto out_elf_end;
971
972         symstrs = elf_getdata(sec, NULL);
973         if (symstrs == NULL)
974                 goto out_elf_end;
975
976         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
977         if (sec_strndx == NULL)
978                 goto out_elf_end;
979
980         secstrs = elf_getdata(sec_strndx, NULL);
981         if (secstrs == NULL)
982                 goto out_elf_end;
983
984         nr_syms = shdr.sh_size / shdr.sh_entsize;
985
986         memset(&sym, 0, sizeof(sym));
987
988         /*
989          * The kernel relocation symbol is needed in advance in order to adjust
990          * kernel maps correctly.
991          */
992         if (ref_reloc_sym_not_found(kmap)) {
993                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
994                         const char *elf_name = elf_sym__name(&sym, symstrs);
995
996                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
997                                 continue;
998                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
999                         map->reloc = kmap->ref_reloc_sym->addr -
1000                                      kmap->ref_reloc_sym->unrelocated_addr;
1001                         break;
1002                 }
1003         }
1004
1005         /*
1006          * Handle any relocation of vdso necessary because older kernels
1007          * attempted to prelink vdso to its virtual address.
1008          */
1009         if (dso__is_vdso(dso))
1010                 map->reloc = map->start - dso->text_offset;
1011
1012         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1013         /*
1014          * Initial kernel and module mappings do not map to the dso.
1015          * Flag the fixups.
1016          */
1017         if (dso->kernel || kmodule) {
1018                 remap_kernel = true;
1019                 adjust_kernel_syms = dso->adjust_symbols;
1020         }
1021         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1022                 struct symbol *f;
1023                 const char *elf_name = elf_sym__name(&sym, symstrs);
1024                 char *demangled = NULL;
1025                 int is_label = elf_sym__is_label(&sym);
1026                 const char *section_name;
1027                 bool used_opd = false;
1028
1029                 if (!is_label && !elf_sym__filter(&sym))
1030                         continue;
1031
1032                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1033                  * don't identify functions, so will confuse the profile
1034                  * output: */
1035                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1036                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1037                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1038                                 continue;
1039                 }
1040
1041                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1042                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1043                         u64 *opd = opddata->d_buf + offset;
1044                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1045                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1046                                         sym.st_value);
1047                         used_opd = true;
1048                 }
1049                 /*
1050                  * When loading symbols in a data mapping, ABS symbols (which
1051                  * has a value of SHN_ABS in its st_shndx) failed at
1052                  * elf_getscn().  And it marks the loading as a failure so
1053                  * already loaded symbols cannot be fixed up.
1054                  *
1055                  * I'm not sure what should be done. Just ignore them for now.
1056                  * - Namhyung Kim
1057                  */
1058                 if (sym.st_shndx == SHN_ABS)
1059                         continue;
1060
1061                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1062                 if (!sec)
1063                         goto out_elf_end;
1064
1065                 gelf_getshdr(sec, &shdr);
1066
1067                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1068                         continue;
1069
1070                 section_name = elf_sec__name(&shdr, secstrs);
1071
1072                 /* On ARM, symbols for thumb functions have 1 added to
1073                  * the symbol address as a flag - remove it */
1074                 if ((ehdr.e_machine == EM_ARM) &&
1075                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1076                     (sym.st_value & 1))
1077                         --sym.st_value;
1078
1079                 if (dso->kernel || kmodule) {
1080                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1081                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1082                                 goto out_elf_end;
1083                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1084                            (!used_opd && syms_ss->adjust_symbols)) {
1085                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1086                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1087                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1088                                   (u64)shdr.sh_offset);
1089                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1090                 }
1091
1092                 demangled = demangle_sym(dso, kmodule, elf_name);
1093                 if (demangled != NULL)
1094                         elf_name = demangled;
1095
1096                 f = symbol__new(sym.st_value, sym.st_size,
1097                                 GELF_ST_BIND(sym.st_info),
1098                                 GELF_ST_TYPE(sym.st_info), elf_name);
1099                 free(demangled);
1100                 if (!f)
1101                         goto out_elf_end;
1102
1103                 arch__sym_update(f, &sym);
1104
1105                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1106                 nr++;
1107         }
1108
1109         /*
1110          * For misannotated, zeroed, ASM function sizes.
1111          */
1112         if (nr > 0) {
1113                 symbols__fixup_end(&dso->symbols);
1114                 symbols__fixup_duplicate(&dso->symbols);
1115                 if (kmap) {
1116                         /*
1117                          * We need to fixup this here too because we create new
1118                          * maps here, for things like vsyscall sections.
1119                          */
1120                         map_groups__fixup_end(kmaps);
1121                 }
1122         }
1123         err = nr;
1124 out_elf_end:
1125         return err;
1126 }
1127
1128 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1129 {
1130         GElf_Phdr phdr;
1131         size_t i, phdrnum;
1132         int err;
1133         u64 sz;
1134
1135         if (elf_getphdrnum(elf, &phdrnum))
1136                 return -1;
1137
1138         for (i = 0; i < phdrnum; i++) {
1139                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1140                         return -1;
1141                 if (phdr.p_type != PT_LOAD)
1142                         continue;
1143                 if (exe) {
1144                         if (!(phdr.p_flags & PF_X))
1145                                 continue;
1146                 } else {
1147                         if (!(phdr.p_flags & PF_R))
1148                                 continue;
1149                 }
1150                 sz = min(phdr.p_memsz, phdr.p_filesz);
1151                 if (!sz)
1152                         continue;
1153                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1154                 if (err)
1155                         return err;
1156         }
1157         return 0;
1158 }
1159
1160 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1161                     bool *is_64_bit)
1162 {
1163         int err;
1164         Elf *elf;
1165
1166         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1167         if (elf == NULL)
1168                 return -1;
1169
1170         if (is_64_bit)
1171                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1172
1173         err = elf_read_maps(elf, exe, mapfn, data);
1174
1175         elf_end(elf);
1176         return err;
1177 }
1178
1179 enum dso_type dso__type_fd(int fd)
1180 {
1181         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1182         GElf_Ehdr ehdr;
1183         Elf_Kind ek;
1184         Elf *elf;
1185
1186         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1187         if (elf == NULL)
1188                 goto out;
1189
1190         ek = elf_kind(elf);
1191         if (ek != ELF_K_ELF)
1192                 goto out_end;
1193
1194         if (gelf_getclass(elf) == ELFCLASS64) {
1195                 dso_type = DSO__TYPE_64BIT;
1196                 goto out_end;
1197         }
1198
1199         if (gelf_getehdr(elf, &ehdr) == NULL)
1200                 goto out_end;
1201
1202         if (ehdr.e_machine == EM_X86_64)
1203                 dso_type = DSO__TYPE_X32BIT;
1204         else
1205                 dso_type = DSO__TYPE_32BIT;
1206 out_end:
1207         elf_end(elf);
1208 out:
1209         return dso_type;
1210 }
1211
1212 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1213 {
1214         ssize_t r;
1215         size_t n;
1216         int err = -1;
1217         char *buf = malloc(page_size);
1218
1219         if (buf == NULL)
1220                 return -1;
1221
1222         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1223                 goto out;
1224
1225         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1226                 goto out;
1227
1228         while (len) {
1229                 n = page_size;
1230                 if (len < n)
1231                         n = len;
1232                 /* Use read because mmap won't work on proc files */
1233                 r = read(from, buf, n);
1234                 if (r < 0)
1235                         goto out;
1236                 if (!r)
1237                         break;
1238                 n = r;
1239                 r = write(to, buf, n);
1240                 if (r < 0)
1241                         goto out;
1242                 if ((size_t)r != n)
1243                         goto out;
1244                 len -= n;
1245         }
1246
1247         err = 0;
1248 out:
1249         free(buf);
1250         return err;
1251 }
1252
1253 struct kcore {
1254         int fd;
1255         int elfclass;
1256         Elf *elf;
1257         GElf_Ehdr ehdr;
1258 };
1259
1260 static int kcore__open(struct kcore *kcore, const char *filename)
1261 {
1262         GElf_Ehdr *ehdr;
1263
1264         kcore->fd = open(filename, O_RDONLY);
1265         if (kcore->fd == -1)
1266                 return -1;
1267
1268         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1269         if (!kcore->elf)
1270                 goto out_close;
1271
1272         kcore->elfclass = gelf_getclass(kcore->elf);
1273         if (kcore->elfclass == ELFCLASSNONE)
1274                 goto out_end;
1275
1276         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1277         if (!ehdr)
1278                 goto out_end;
1279
1280         return 0;
1281
1282 out_end:
1283         elf_end(kcore->elf);
1284 out_close:
1285         close(kcore->fd);
1286         return -1;
1287 }
1288
1289 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1290                        bool temp)
1291 {
1292         kcore->elfclass = elfclass;
1293
1294         if (temp)
1295                 kcore->fd = mkstemp(filename);
1296         else
1297                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1298         if (kcore->fd == -1)
1299                 return -1;
1300
1301         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1302         if (!kcore->elf)
1303                 goto out_close;
1304
1305         if (!gelf_newehdr(kcore->elf, elfclass))
1306                 goto out_end;
1307
1308         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1309
1310         return 0;
1311
1312 out_end:
1313         elf_end(kcore->elf);
1314 out_close:
1315         close(kcore->fd);
1316         unlink(filename);
1317         return -1;
1318 }
1319
1320 static void kcore__close(struct kcore *kcore)
1321 {
1322         elf_end(kcore->elf);
1323         close(kcore->fd);
1324 }
1325
1326 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1327 {
1328         GElf_Ehdr *ehdr = &to->ehdr;
1329         GElf_Ehdr *kehdr = &from->ehdr;
1330
1331         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1332         ehdr->e_type      = kehdr->e_type;
1333         ehdr->e_machine   = kehdr->e_machine;
1334         ehdr->e_version   = kehdr->e_version;
1335         ehdr->e_entry     = 0;
1336         ehdr->e_shoff     = 0;
1337         ehdr->e_flags     = kehdr->e_flags;
1338         ehdr->e_phnum     = count;
1339         ehdr->e_shentsize = 0;
1340         ehdr->e_shnum     = 0;
1341         ehdr->e_shstrndx  = 0;
1342
1343         if (from->elfclass == ELFCLASS32) {
1344                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1345                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1346                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1347         } else {
1348                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1349                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1350                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1351         }
1352
1353         if (!gelf_update_ehdr(to->elf, ehdr))
1354                 return -1;
1355
1356         if (!gelf_newphdr(to->elf, count))
1357                 return -1;
1358
1359         return 0;
1360 }
1361
1362 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1363                            u64 addr, u64 len)
1364 {
1365         GElf_Phdr phdr = {
1366                 .p_type         = PT_LOAD,
1367                 .p_flags        = PF_R | PF_W | PF_X,
1368                 .p_offset       = offset,
1369                 .p_vaddr        = addr,
1370                 .p_paddr        = 0,
1371                 .p_filesz       = len,
1372                 .p_memsz        = len,
1373                 .p_align        = page_size,
1374         };
1375
1376         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1377                 return -1;
1378
1379         return 0;
1380 }
1381
1382 static off_t kcore__write(struct kcore *kcore)
1383 {
1384         return elf_update(kcore->elf, ELF_C_WRITE);
1385 }
1386
1387 struct phdr_data {
1388         off_t offset;
1389         off_t rel;
1390         u64 addr;
1391         u64 len;
1392         struct list_head node;
1393         struct phdr_data *remaps;
1394 };
1395
1396 struct sym_data {
1397         u64 addr;
1398         struct list_head node;
1399 };
1400
1401 struct kcore_copy_info {
1402         u64 stext;
1403         u64 etext;
1404         u64 first_symbol;
1405         u64 last_symbol;
1406         u64 first_module;
1407         u64 last_module_symbol;
1408         size_t phnum;
1409         struct list_head phdrs;
1410         struct list_head syms;
1411 };
1412
1413 #define kcore_copy__for_each_phdr(k, p) \
1414         list_for_each_entry((p), &(k)->phdrs, node)
1415
1416 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1417 {
1418         struct phdr_data *p = zalloc(sizeof(*p));
1419
1420         if (p) {
1421                 p->addr   = addr;
1422                 p->len    = len;
1423                 p->offset = offset;
1424         }
1425
1426         return p;
1427 }
1428
1429 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1430                                                  u64 addr, u64 len,
1431                                                  off_t offset)
1432 {
1433         struct phdr_data *p = phdr_data__new(addr, len, offset);
1434
1435         if (p)
1436                 list_add_tail(&p->node, &kci->phdrs);
1437
1438         return p;
1439 }
1440
1441 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1442 {
1443         struct phdr_data *p, *tmp;
1444
1445         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1446                 list_del(&p->node);
1447                 free(p);
1448         }
1449 }
1450
1451 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1452                                             u64 addr)
1453 {
1454         struct sym_data *s = zalloc(sizeof(*s));
1455
1456         if (s) {
1457                 s->addr = addr;
1458                 list_add_tail(&s->node, &kci->syms);
1459         }
1460
1461         return s;
1462 }
1463
1464 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1465 {
1466         struct sym_data *s, *tmp;
1467
1468         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1469                 list_del(&s->node);
1470                 free(s);
1471         }
1472 }
1473
1474 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1475                                         u64 start)
1476 {
1477         struct kcore_copy_info *kci = arg;
1478
1479         if (!kallsyms__is_function(type))
1480                 return 0;
1481
1482         if (strchr(name, '[')) {
1483                 if (start > kci->last_module_symbol)
1484                         kci->last_module_symbol = start;
1485                 return 0;
1486         }
1487
1488         if (!kci->first_symbol || start < kci->first_symbol)
1489                 kci->first_symbol = start;
1490
1491         if (!kci->last_symbol || start > kci->last_symbol)
1492                 kci->last_symbol = start;
1493
1494         if (!strcmp(name, "_stext")) {
1495                 kci->stext = start;
1496                 return 0;
1497         }
1498
1499         if (!strcmp(name, "_etext")) {
1500                 kci->etext = start;
1501                 return 0;
1502         }
1503
1504         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1505                 return -1;
1506
1507         return 0;
1508 }
1509
1510 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1511                                       const char *dir)
1512 {
1513         char kallsyms_filename[PATH_MAX];
1514
1515         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1516
1517         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1518                 return -1;
1519
1520         if (kallsyms__parse(kallsyms_filename, kci,
1521                             kcore_copy__process_kallsyms) < 0)
1522                 return -1;
1523
1524         return 0;
1525 }
1526
1527 static int kcore_copy__process_modules(void *arg,
1528                                        const char *name __maybe_unused,
1529                                        u64 start, u64 size __maybe_unused)
1530 {
1531         struct kcore_copy_info *kci = arg;
1532
1533         if (!kci->first_module || start < kci->first_module)
1534                 kci->first_module = start;
1535
1536         return 0;
1537 }
1538
1539 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1540                                      const char *dir)
1541 {
1542         char modules_filename[PATH_MAX];
1543
1544         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1545
1546         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1547                 return -1;
1548
1549         if (modules__parse(modules_filename, kci,
1550                            kcore_copy__process_modules) < 0)
1551                 return -1;
1552
1553         return 0;
1554 }
1555
1556 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1557                            u64 pgoff, u64 s, u64 e)
1558 {
1559         u64 len, offset;
1560
1561         if (s < start || s >= end)
1562                 return 0;
1563
1564         offset = (s - start) + pgoff;
1565         len = e < end ? e - s : end - s;
1566
1567         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1568 }
1569
1570 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1571 {
1572         struct kcore_copy_info *kci = data;
1573         u64 end = start + len;
1574         struct sym_data *sdat;
1575
1576         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1577                 return -1;
1578
1579         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1580                             kci->last_module_symbol))
1581                 return -1;
1582
1583         list_for_each_entry(sdat, &kci->syms, node) {
1584                 u64 s = round_down(sdat->addr, page_size);
1585
1586                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1587                         return -1;
1588         }
1589
1590         return 0;
1591 }
1592
1593 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1594 {
1595         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1596                 return -1;
1597
1598         return 0;
1599 }
1600
1601 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1602 {
1603         struct phdr_data *p, *k = NULL;
1604         u64 kend;
1605
1606         if (!kci->stext)
1607                 return;
1608
1609         /* Find phdr that corresponds to the kernel map (contains stext) */
1610         kcore_copy__for_each_phdr(kci, p) {
1611                 u64 pend = p->addr + p->len - 1;
1612
1613                 if (p->addr <= kci->stext && pend >= kci->stext) {
1614                         k = p;
1615                         break;
1616                 }
1617         }
1618
1619         if (!k)
1620                 return;
1621
1622         kend = k->offset + k->len;
1623
1624         /* Find phdrs that remap the kernel */
1625         kcore_copy__for_each_phdr(kci, p) {
1626                 u64 pend = p->offset + p->len;
1627
1628                 if (p == k)
1629                         continue;
1630
1631                 if (p->offset >= k->offset && pend <= kend)
1632                         p->remaps = k;
1633         }
1634 }
1635
1636 static void kcore_copy__layout(struct kcore_copy_info *kci)
1637 {
1638         struct phdr_data *p;
1639         off_t rel = 0;
1640
1641         kcore_copy__find_remaps(kci);
1642
1643         kcore_copy__for_each_phdr(kci, p) {
1644                 if (!p->remaps) {
1645                         p->rel = rel;
1646                         rel += p->len;
1647                 }
1648                 kci->phnum += 1;
1649         }
1650
1651         kcore_copy__for_each_phdr(kci, p) {
1652                 struct phdr_data *k = p->remaps;
1653
1654                 if (k)
1655                         p->rel = p->offset - k->offset + k->rel;
1656         }
1657 }
1658
1659 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1660                                  Elf *elf)
1661 {
1662         if (kcore_copy__parse_kallsyms(kci, dir))
1663                 return -1;
1664
1665         if (kcore_copy__parse_modules(kci, dir))
1666                 return -1;
1667
1668         if (kci->stext)
1669                 kci->stext = round_down(kci->stext, page_size);
1670         else
1671                 kci->stext = round_down(kci->first_symbol, page_size);
1672
1673         if (kci->etext) {
1674                 kci->etext = round_up(kci->etext, page_size);
1675         } else if (kci->last_symbol) {
1676                 kci->etext = round_up(kci->last_symbol, page_size);
1677                 kci->etext += page_size;
1678         }
1679
1680         kci->first_module = round_down(kci->first_module, page_size);
1681
1682         if (kci->last_module_symbol) {
1683                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1684                                                    page_size);
1685                 kci->last_module_symbol += page_size;
1686         }
1687
1688         if (!kci->stext || !kci->etext)
1689                 return -1;
1690
1691         if (kci->first_module && !kci->last_module_symbol)
1692                 return -1;
1693
1694         if (kcore_copy__read_maps(kci, elf))
1695                 return -1;
1696
1697         kcore_copy__layout(kci);
1698
1699         return 0;
1700 }
1701
1702 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1703                                  const char *name)
1704 {
1705         char from_filename[PATH_MAX];
1706         char to_filename[PATH_MAX];
1707
1708         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1709         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1710
1711         return copyfile_mode(from_filename, to_filename, 0400);
1712 }
1713
1714 static int kcore_copy__unlink(const char *dir, const char *name)
1715 {
1716         char filename[PATH_MAX];
1717
1718         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1719
1720         return unlink(filename);
1721 }
1722
1723 static int kcore_copy__compare_fds(int from, int to)
1724 {
1725         char *buf_from;
1726         char *buf_to;
1727         ssize_t ret;
1728         size_t len;
1729         int err = -1;
1730
1731         buf_from = malloc(page_size);
1732         buf_to = malloc(page_size);
1733         if (!buf_from || !buf_to)
1734                 goto out;
1735
1736         while (1) {
1737                 /* Use read because mmap won't work on proc files */
1738                 ret = read(from, buf_from, page_size);
1739                 if (ret < 0)
1740                         goto out;
1741
1742                 if (!ret)
1743                         break;
1744
1745                 len = ret;
1746
1747                 if (readn(to, buf_to, len) != (int)len)
1748                         goto out;
1749
1750                 if (memcmp(buf_from, buf_to, len))
1751                         goto out;
1752         }
1753
1754         err = 0;
1755 out:
1756         free(buf_to);
1757         free(buf_from);
1758         return err;
1759 }
1760
1761 static int kcore_copy__compare_files(const char *from_filename,
1762                                      const char *to_filename)
1763 {
1764         int from, to, err = -1;
1765
1766         from = open(from_filename, O_RDONLY);
1767         if (from < 0)
1768                 return -1;
1769
1770         to = open(to_filename, O_RDONLY);
1771         if (to < 0)
1772                 goto out_close_from;
1773
1774         err = kcore_copy__compare_fds(from, to);
1775
1776         close(to);
1777 out_close_from:
1778         close(from);
1779         return err;
1780 }
1781
1782 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1783                                     const char *name)
1784 {
1785         char from_filename[PATH_MAX];
1786         char to_filename[PATH_MAX];
1787
1788         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1789         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1790
1791         return kcore_copy__compare_files(from_filename, to_filename);
1792 }
1793
1794 /**
1795  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1796  * @from_dir: from directory
1797  * @to_dir: to directory
1798  *
1799  * This function copies kallsyms, modules and kcore files from one directory to
1800  * another.  kallsyms and modules are copied entirely.  Only code segments are
1801  * copied from kcore.  It is assumed that two segments suffice: one for the
1802  * kernel proper and one for all the modules.  The code segments are determined
1803  * from kallsyms and modules files.  The kernel map starts at _stext or the
1804  * lowest function symbol, and ends at _etext or the highest function symbol.
1805  * The module map starts at the lowest module address and ends at the highest
1806  * module symbol.  Start addresses are rounded down to the nearest page.  End
1807  * addresses are rounded up to the nearest page.  An extra page is added to the
1808  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1809  * symbol too.  Because it contains only code sections, the resulting kcore is
1810  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1811  * is not the same for the kernel map and the modules map.  That happens because
1812  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1813  * kallsyms and modules files are compared with their copies to check that
1814  * modules have not been loaded or unloaded while the copies were taking place.
1815  *
1816  * Return: %0 on success, %-1 on failure.
1817  */
1818 int kcore_copy(const char *from_dir, const char *to_dir)
1819 {
1820         struct kcore kcore;
1821         struct kcore extract;
1822         int idx = 0, err = -1;
1823         off_t offset, sz;
1824         struct kcore_copy_info kci = { .stext = 0, };
1825         char kcore_filename[PATH_MAX];
1826         char extract_filename[PATH_MAX];
1827         struct phdr_data *p;
1828
1829         INIT_LIST_HEAD(&kci.phdrs);
1830         INIT_LIST_HEAD(&kci.syms);
1831
1832         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1833                 return -1;
1834
1835         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1836                 goto out_unlink_kallsyms;
1837
1838         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1839         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1840
1841         if (kcore__open(&kcore, kcore_filename))
1842                 goto out_unlink_modules;
1843
1844         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1845                 goto out_kcore_close;
1846
1847         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1848                 goto out_kcore_close;
1849
1850         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1851                 goto out_extract_close;
1852
1853         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1854                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1855         offset = round_up(offset, page_size);
1856
1857         kcore_copy__for_each_phdr(&kci, p) {
1858                 off_t offs = p->rel + offset;
1859
1860                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1861                         goto out_extract_close;
1862         }
1863
1864         sz = kcore__write(&extract);
1865         if (sz < 0 || sz > offset)
1866                 goto out_extract_close;
1867
1868         kcore_copy__for_each_phdr(&kci, p) {
1869                 off_t offs = p->rel + offset;
1870
1871                 if (p->remaps)
1872                         continue;
1873                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1874                         goto out_extract_close;
1875         }
1876
1877         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1878                 goto out_extract_close;
1879
1880         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1881                 goto out_extract_close;
1882
1883         err = 0;
1884
1885 out_extract_close:
1886         kcore__close(&extract);
1887         if (err)
1888                 unlink(extract_filename);
1889 out_kcore_close:
1890         kcore__close(&kcore);
1891 out_unlink_modules:
1892         if (err)
1893                 kcore_copy__unlink(to_dir, "modules");
1894 out_unlink_kallsyms:
1895         if (err)
1896                 kcore_copy__unlink(to_dir, "kallsyms");
1897
1898         kcore_copy__free_phdrs(&kci);
1899         kcore_copy__free_syms(&kci);
1900
1901         return err;
1902 }
1903
1904 int kcore_extract__create(struct kcore_extract *kce)
1905 {
1906         struct kcore kcore;
1907         struct kcore extract;
1908         size_t count = 1;
1909         int idx = 0, err = -1;
1910         off_t offset = page_size, sz;
1911
1912         if (kcore__open(&kcore, kce->kcore_filename))
1913                 return -1;
1914
1915         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1916         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1917                 goto out_kcore_close;
1918
1919         if (kcore__copy_hdr(&kcore, &extract, count))
1920                 goto out_extract_close;
1921
1922         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1923                 goto out_extract_close;
1924
1925         sz = kcore__write(&extract);
1926         if (sz < 0 || sz > offset)
1927                 goto out_extract_close;
1928
1929         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1930                 goto out_extract_close;
1931
1932         err = 0;
1933
1934 out_extract_close:
1935         kcore__close(&extract);
1936         if (err)
1937                 unlink(kce->extract_filename);
1938 out_kcore_close:
1939         kcore__close(&kcore);
1940
1941         return err;
1942 }
1943
1944 void kcore_extract__delete(struct kcore_extract *kce)
1945 {
1946         unlink(kce->extract_filename);
1947 }
1948
1949 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1950 /**
1951  * populate_sdt_note : Parse raw data and identify SDT note
1952  * @elf: elf of the opened file
1953  * @data: raw data of a section with description offset applied
1954  * @len: note description size
1955  * @type: type of the note
1956  * @sdt_notes: List to add the SDT note
1957  *
1958  * Responsible for parsing the @data in section .note.stapsdt in @elf and
1959  * if its an SDT note, it appends to @sdt_notes list.
1960  */
1961 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1962                              struct list_head *sdt_notes)
1963 {
1964         const char *provider, *name, *args;
1965         struct sdt_note *tmp = NULL;
1966         GElf_Ehdr ehdr;
1967         GElf_Addr base_off = 0;
1968         GElf_Shdr shdr;
1969         int ret = -EINVAL;
1970
1971         union {
1972                 Elf64_Addr a64[NR_ADDR];
1973                 Elf32_Addr a32[NR_ADDR];
1974         } buf;
1975
1976         Elf_Data dst = {
1977                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1978                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1979                 .d_off = 0, .d_align = 0
1980         };
1981         Elf_Data src = {
1982                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1983                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1984                 .d_align = 0
1985         };
1986
1987         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1988         if (!tmp) {
1989                 ret = -ENOMEM;
1990                 goto out_err;
1991         }
1992
1993         INIT_LIST_HEAD(&tmp->note_list);
1994
1995         if (len < dst.d_size + 3)
1996                 goto out_free_note;
1997
1998         /* Translation from file representation to memory representation */
1999         if (gelf_xlatetom(*elf, &dst, &src,
2000                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2001                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2002                 goto out_free_note;
2003         }
2004
2005         /* Populate the fields of sdt_note */
2006         provider = data + dst.d_size;
2007
2008         name = (const char *)memchr(provider, '\0', data + len - provider);
2009         if (name++ == NULL)
2010                 goto out_free_note;
2011
2012         tmp->provider = strdup(provider);
2013         if (!tmp->provider) {
2014                 ret = -ENOMEM;
2015                 goto out_free_note;
2016         }
2017         tmp->name = strdup(name);
2018         if (!tmp->name) {
2019                 ret = -ENOMEM;
2020                 goto out_free_prov;
2021         }
2022
2023         args = memchr(name, '\0', data + len - name);
2024
2025         /*
2026          * There is no argument if:
2027          * - We reached the end of the note;
2028          * - There is not enough room to hold a potential string;
2029          * - The argument string is empty or just contains ':'.
2030          */
2031         if (args == NULL || data + len - args < 2 ||
2032                 args[1] == ':' || args[1] == '\0')
2033                 tmp->args = NULL;
2034         else {
2035                 tmp->args = strdup(++args);
2036                 if (!tmp->args) {
2037                         ret = -ENOMEM;
2038                         goto out_free_name;
2039                 }
2040         }
2041
2042         if (gelf_getclass(*elf) == ELFCLASS32) {
2043                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2044                 tmp->bit32 = true;
2045         } else {
2046                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2047                 tmp->bit32 = false;
2048         }
2049
2050         if (!gelf_getehdr(*elf, &ehdr)) {
2051                 pr_debug("%s : cannot get elf header.\n", __func__);
2052                 ret = -EBADF;
2053                 goto out_free_args;
2054         }
2055
2056         /* Adjust the prelink effect :
2057          * Find out the .stapsdt.base section.
2058          * This scn will help us to handle prelinking (if present).
2059          * Compare the retrieved file offset of the base section with the
2060          * base address in the description of the SDT note. If its different,
2061          * then accordingly, adjust the note location.
2062          */
2063         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
2064                 base_off = shdr.sh_offset;
2065                 if (base_off) {
2066                         if (tmp->bit32)
2067                                 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
2068                                         tmp->addr.a32[1];
2069                         else
2070                                 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
2071                                         tmp->addr.a64[1];
2072                 }
2073         }
2074
2075         list_add_tail(&tmp->note_list, sdt_notes);
2076         return 0;
2077
2078 out_free_args:
2079         free(tmp->args);
2080 out_free_name:
2081         free(tmp->name);
2082 out_free_prov:
2083         free(tmp->provider);
2084 out_free_note:
2085         free(tmp);
2086 out_err:
2087         return ret;
2088 }
2089
2090 /**
2091  * construct_sdt_notes_list : constructs a list of SDT notes
2092  * @elf : elf to look into
2093  * @sdt_notes : empty list_head
2094  *
2095  * Scans the sections in 'elf' for the section
2096  * .note.stapsdt. It, then calls populate_sdt_note to find
2097  * out the SDT events and populates the 'sdt_notes'.
2098  */
2099 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2100 {
2101         GElf_Ehdr ehdr;
2102         Elf_Scn *scn = NULL;
2103         Elf_Data *data;
2104         GElf_Shdr shdr;
2105         size_t shstrndx, next;
2106         GElf_Nhdr nhdr;
2107         size_t name_off, desc_off, offset;
2108         int ret = 0;
2109
2110         if (gelf_getehdr(elf, &ehdr) == NULL) {
2111                 ret = -EBADF;
2112                 goto out_ret;
2113         }
2114         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2115                 ret = -EBADF;
2116                 goto out_ret;
2117         }
2118
2119         /* Look for the required section */
2120         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2121         if (!scn) {
2122                 ret = -ENOENT;
2123                 goto out_ret;
2124         }
2125
2126         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2127                 ret = -ENOENT;
2128                 goto out_ret;
2129         }
2130
2131         data = elf_getdata(scn, NULL);
2132
2133         /* Get the SDT notes */
2134         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2135                                               &desc_off)) > 0; offset = next) {
2136                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2137                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2138                             sizeof(SDT_NOTE_NAME))) {
2139                         /* Check the type of the note */
2140                         if (nhdr.n_type != SDT_NOTE_TYPE)
2141                                 goto out_ret;
2142
2143                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2144                                                 nhdr.n_descsz, sdt_notes);
2145                         if (ret < 0)
2146                                 goto out_ret;
2147                 }
2148         }
2149         if (list_empty(sdt_notes))
2150                 ret = -ENOENT;
2151
2152 out_ret:
2153         return ret;
2154 }
2155
2156 /**
2157  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2158  * @head : empty list_head
2159  * @target : file to find SDT notes from
2160  *
2161  * This opens the file, initializes
2162  * the ELF and then calls construct_sdt_notes_list.
2163  */
2164 int get_sdt_note_list(struct list_head *head, const char *target)
2165 {
2166         Elf *elf;
2167         int fd, ret;
2168
2169         fd = open(target, O_RDONLY);
2170         if (fd < 0)
2171                 return -EBADF;
2172
2173         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2174         if (!elf) {
2175                 ret = -EBADF;
2176                 goto out_close;
2177         }
2178         ret = construct_sdt_notes_list(elf, head);
2179         elf_end(elf);
2180 out_close:
2181         close(fd);
2182         return ret;
2183 }
2184
2185 /**
2186  * cleanup_sdt_note_list : free the sdt notes' list
2187  * @sdt_notes: sdt notes' list
2188  *
2189  * Free up the SDT notes in @sdt_notes.
2190  * Returns the number of SDT notes free'd.
2191  */
2192 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2193 {
2194         struct sdt_note *tmp, *pos;
2195         int nr_free = 0;
2196
2197         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2198                 list_del(&pos->note_list);
2199                 free(pos->name);
2200                 free(pos->provider);
2201                 free(pos);
2202                 nr_free++;
2203         }
2204         return nr_free;
2205 }
2206
2207 /**
2208  * sdt_notes__get_count: Counts the number of sdt events
2209  * @start: list_head to sdt_notes list
2210  *
2211  * Returns the number of SDT notes in a list
2212  */
2213 int sdt_notes__get_count(struct list_head *start)
2214 {
2215         struct sdt_note *sdt_ptr;
2216         int count = 0;
2217
2218         list_for_each_entry(sdt_ptr, start, note_list)
2219                 count++;
2220         return count;
2221 }
2222 #endif
2223
2224 void symbol__elf_init(void)
2225 {
2226         elf_version(EV_CURRENT);
2227 }