10 #include <symbol/kallsyms.h>
13 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
14 static int elf_getphdrnum(Elf
*elf
, size_t *dst
)
19 ehdr
= gelf_getehdr(elf
, &gehdr
);
29 #ifndef NT_GNU_BUILD_ID
30 #define NT_GNU_BUILD_ID 3
34 * elf_symtab__for_each_symbol - iterate thru all the symbols
36 * @syms: struct elf_symtab instance to iterate
38 * @sym: GElf_Sym iterator
40 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
41 for (idx = 0, gelf_getsym(syms, idx, &sym);\
43 idx++, gelf_getsym(syms, idx, &sym))
45 static inline uint8_t elf_sym__type(const GElf_Sym
*sym
)
47 return GELF_ST_TYPE(sym
->st_info
);
50 static inline int elf_sym__is_function(const GElf_Sym
*sym
)
52 return elf_sym__type(sym
) == STT_FUNC
&&
54 sym
->st_shndx
!= SHN_UNDEF
;
57 static inline bool elf_sym__is_object(const GElf_Sym
*sym
)
59 return elf_sym__type(sym
) == STT_OBJECT
&&
61 sym
->st_shndx
!= SHN_UNDEF
;
64 static inline int elf_sym__is_label(const GElf_Sym
*sym
)
66 return elf_sym__type(sym
) == STT_NOTYPE
&&
68 sym
->st_shndx
!= SHN_UNDEF
&&
69 sym
->st_shndx
!= SHN_ABS
;
72 static bool elf_sym__is_a(GElf_Sym
*sym
, enum map_type type
)
76 return elf_sym__is_function(sym
);
78 return elf_sym__is_object(sym
);
84 static inline const char *elf_sym__name(const GElf_Sym
*sym
,
85 const Elf_Data
*symstrs
)
87 return symstrs
->d_buf
+ sym
->st_name
;
90 static inline const char *elf_sec__name(const GElf_Shdr
*shdr
,
91 const Elf_Data
*secstrs
)
93 return secstrs
->d_buf
+ shdr
->sh_name
;
96 static inline int elf_sec__is_text(const GElf_Shdr
*shdr
,
97 const Elf_Data
*secstrs
)
99 return strstr(elf_sec__name(shdr
, secstrs
), "text") != NULL
;
102 static inline bool elf_sec__is_data(const GElf_Shdr
*shdr
,
103 const Elf_Data
*secstrs
)
105 return strstr(elf_sec__name(shdr
, secstrs
), "data") != NULL
;
108 static bool elf_sec__is_a(GElf_Shdr
*shdr
, Elf_Data
*secstrs
,
113 return elf_sec__is_text(shdr
, secstrs
);
115 return elf_sec__is_data(shdr
, secstrs
);
121 static size_t elf_addr_to_index(Elf
*elf
, GElf_Addr addr
)
127 while ((sec
= elf_nextscn(elf
, sec
)) != NULL
) {
128 gelf_getshdr(sec
, &shdr
);
130 if ((addr
>= shdr
.sh_addr
) &&
131 (addr
< (shdr
.sh_addr
+ shdr
.sh_size
)))
140 Elf_Scn
*elf_section_by_name(Elf
*elf
, GElf_Ehdr
*ep
,
141 GElf_Shdr
*shp
, const char *name
, size_t *idx
)
146 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
147 if (!elf_rawdata(elf_getscn(elf
, ep
->e_shstrndx
), NULL
))
150 while ((sec
= elf_nextscn(elf
, sec
)) != NULL
) {
153 gelf_getshdr(sec
, shp
);
154 str
= elf_strptr(elf
, ep
->e_shstrndx
, shp
->sh_name
);
155 if (str
&& !strcmp(name
, str
)) {
166 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
167 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
169 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
171 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
172 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
174 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
177 * We need to check if we have a .dynsym, so that we can handle the
178 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
179 * .dynsym or .symtab).
180 * And always look at the original dso, not at debuginfo packages, that
181 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
183 int dso__synthesize_plt_symbols(struct dso
*dso
, struct symsrc
*ss
, struct map
*map
,
184 symbol_filter_t filter
)
186 uint32_t nr_rel_entries
, idx
;
191 GElf_Shdr shdr_rel_plt
, shdr_dynsym
;
192 Elf_Data
*reldata
, *syms
, *symstrs
;
193 Elf_Scn
*scn_plt_rel
, *scn_symstrs
, *scn_dynsym
;
196 char sympltname
[1024];
198 int nr
= 0, symidx
, err
= 0;
206 scn_dynsym
= ss
->dynsym
;
207 shdr_dynsym
= ss
->dynshdr
;
208 dynsym_idx
= ss
->dynsym_idx
;
210 if (scn_dynsym
== NULL
)
213 scn_plt_rel
= elf_section_by_name(elf
, &ehdr
, &shdr_rel_plt
,
215 if (scn_plt_rel
== NULL
) {
216 scn_plt_rel
= elf_section_by_name(elf
, &ehdr
, &shdr_rel_plt
,
218 if (scn_plt_rel
== NULL
)
224 if (shdr_rel_plt
.sh_link
!= dynsym_idx
)
227 if (elf_section_by_name(elf
, &ehdr
, &shdr_plt
, ".plt", NULL
) == NULL
)
231 * Fetch the relocation section to find the idxes to the GOT
232 * and the symbols in the .dynsym they refer to.
234 reldata
= elf_getdata(scn_plt_rel
, NULL
);
238 syms
= elf_getdata(scn_dynsym
, NULL
);
242 scn_symstrs
= elf_getscn(elf
, shdr_dynsym
.sh_link
);
243 if (scn_symstrs
== NULL
)
246 symstrs
= elf_getdata(scn_symstrs
, NULL
);
250 if (symstrs
->d_size
== 0)
253 nr_rel_entries
= shdr_rel_plt
.sh_size
/ shdr_rel_plt
.sh_entsize
;
254 plt_offset
= shdr_plt
.sh_offset
;
256 if (shdr_rel_plt
.sh_type
== SHT_RELA
) {
257 GElf_Rela pos_mem
, *pos
;
259 elf_section__for_each_rela(reldata
, pos
, pos_mem
, idx
,
261 symidx
= GELF_R_SYM(pos
->r_info
);
262 plt_offset
+= shdr_plt
.sh_entsize
;
263 gelf_getsym(syms
, symidx
, &sym
);
264 snprintf(sympltname
, sizeof(sympltname
),
265 "%s@plt", elf_sym__name(&sym
, symstrs
));
267 f
= symbol__new(plt_offset
, shdr_plt
.sh_entsize
,
268 STB_GLOBAL
, sympltname
);
272 if (filter
&& filter(map
, f
))
275 symbols__insert(&dso
->symbols
[map
->type
], f
);
279 } else if (shdr_rel_plt
.sh_type
== SHT_REL
) {
280 GElf_Rel pos_mem
, *pos
;
281 elf_section__for_each_rel(reldata
, pos
, pos_mem
, idx
,
283 symidx
= GELF_R_SYM(pos
->r_info
);
284 plt_offset
+= shdr_plt
.sh_entsize
;
285 gelf_getsym(syms
, symidx
, &sym
);
286 snprintf(sympltname
, sizeof(sympltname
),
287 "%s@plt", elf_sym__name(&sym
, symstrs
));
289 f
= symbol__new(plt_offset
, shdr_plt
.sh_entsize
,
290 STB_GLOBAL
, sympltname
);
294 if (filter
&& filter(map
, f
))
297 symbols__insert(&dso
->symbols
[map
->type
], f
);
307 pr_debug("%s: problems reading %s PLT info.\n",
308 __func__
, dso
->long_name
);
313 * Align offset to 4 bytes as needed for note name and descriptor data.
315 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
317 static int elf_read_build_id(Elf
*elf
, void *bf
, size_t size
)
327 if (size
< BUILD_ID_SIZE
)
334 if (gelf_getehdr(elf
, &ehdr
) == NULL
) {
335 pr_err("%s: cannot get elf header.\n", __func__
);
340 * Check following sections for notes:
341 * '.note.gnu.build-id'
343 * '.note' (VDSO specific)
346 sec
= elf_section_by_name(elf
, &ehdr
, &shdr
,
347 ".note.gnu.build-id", NULL
);
351 sec
= elf_section_by_name(elf
, &ehdr
, &shdr
,
356 sec
= elf_section_by_name(elf
, &ehdr
, &shdr
,
365 data
= elf_getdata(sec
, NULL
);
370 while (ptr
< (data
->d_buf
+ data
->d_size
)) {
371 GElf_Nhdr
*nhdr
= ptr
;
372 size_t namesz
= NOTE_ALIGN(nhdr
->n_namesz
),
373 descsz
= NOTE_ALIGN(nhdr
->n_descsz
);
376 ptr
+= sizeof(*nhdr
);
379 if (nhdr
->n_type
== NT_GNU_BUILD_ID
&&
380 nhdr
->n_namesz
== sizeof("GNU")) {
381 if (memcmp(name
, "GNU", sizeof("GNU")) == 0) {
382 size_t sz
= min(size
, descsz
);
384 memset(bf
+ sz
, 0, size
- sz
);
396 int filename__read_build_id(const char *filename
, void *bf
, size_t size
)
401 if (size
< BUILD_ID_SIZE
)
404 fd
= open(filename
, O_RDONLY
);
408 elf
= elf_begin(fd
, PERF_ELF_C_READ_MMAP
, NULL
);
410 pr_debug2("%s: cannot read %s ELF file.\n", __func__
, filename
);
414 err
= elf_read_build_id(elf
, bf
, size
);
423 int sysfs__read_build_id(const char *filename
, void *build_id
, size_t size
)
427 if (size
< BUILD_ID_SIZE
)
430 fd
= open(filename
, O_RDONLY
);
437 size_t namesz
, descsz
;
439 if (read(fd
, &nhdr
, sizeof(nhdr
)) != sizeof(nhdr
))
442 namesz
= NOTE_ALIGN(nhdr
.n_namesz
);
443 descsz
= NOTE_ALIGN(nhdr
.n_descsz
);
444 if (nhdr
.n_type
== NT_GNU_BUILD_ID
&&
445 nhdr
.n_namesz
== sizeof("GNU")) {
446 if (read(fd
, bf
, namesz
) != (ssize_t
)namesz
)
448 if (memcmp(bf
, "GNU", sizeof("GNU")) == 0) {
449 size_t sz
= min(descsz
, size
);
450 if (read(fd
, build_id
, sz
) == (ssize_t
)sz
) {
451 memset(build_id
+ sz
, 0, size
- sz
);
455 } else if (read(fd
, bf
, descsz
) != (ssize_t
)descsz
)
458 int n
= namesz
+ descsz
;
459 if (read(fd
, bf
, n
) != n
)
468 int filename__read_debuglink(const char *filename
, char *debuglink
,
479 fd
= open(filename
, O_RDONLY
);
483 elf
= elf_begin(fd
, PERF_ELF_C_READ_MMAP
, NULL
);
485 pr_debug2("%s: cannot read %s ELF file.\n", __func__
, filename
);
493 if (gelf_getehdr(elf
, &ehdr
) == NULL
) {
494 pr_err("%s: cannot get elf header.\n", __func__
);
498 sec
= elf_section_by_name(elf
, &ehdr
, &shdr
,
499 ".gnu_debuglink", NULL
);
503 data
= elf_getdata(sec
, NULL
);
507 /* the start of this section is a zero-terminated string */
508 strncpy(debuglink
, data
->d_buf
, size
);
520 static int dso__swap_init(struct dso
*dso
, unsigned char eidata
)
522 static unsigned int const endian
= 1;
524 dso
->needs_swap
= DSO_SWAP__NO
;
528 /* We are big endian, DSO is little endian. */
529 if (*(unsigned char const *)&endian
!= 1)
530 dso
->needs_swap
= DSO_SWAP__YES
;
534 /* We are little endian, DSO is big endian. */
535 if (*(unsigned char const *)&endian
!= 0)
536 dso
->needs_swap
= DSO_SWAP__YES
;
540 pr_err("unrecognized DSO data encoding %d\n", eidata
);
547 bool symsrc__possibly_runtime(struct symsrc
*ss
)
549 return ss
->dynsym
|| ss
->opdsec
;
552 bool symsrc__has_symtab(struct symsrc
*ss
)
554 return ss
->symtab
!= NULL
;
557 void symsrc__destroy(struct symsrc
*ss
)
564 int symsrc__init(struct symsrc
*ss
, struct dso
*dso
, const char *name
,
565 enum dso_binary_type type
)
572 fd
= open(name
, O_RDONLY
);
576 elf
= elf_begin(fd
, PERF_ELF_C_READ_MMAP
, NULL
);
578 pr_debug("%s: cannot read %s ELF file.\n", __func__
, name
);
582 if (gelf_getehdr(elf
, &ehdr
) == NULL
) {
583 pr_debug("%s: cannot get elf header.\n", __func__
);
587 if (dso__swap_init(dso
, ehdr
.e_ident
[EI_DATA
]))
590 /* Always reject images with a mismatched build-id: */
591 if (dso
->has_build_id
) {
592 u8 build_id
[BUILD_ID_SIZE
];
594 if (elf_read_build_id(elf
, build_id
, BUILD_ID_SIZE
) < 0)
597 if (!dso__build_id_equal(dso
, build_id
))
601 ss
->symtab
= elf_section_by_name(elf
, &ehdr
, &ss
->symshdr
, ".symtab",
603 if (ss
->symshdr
.sh_type
!= SHT_SYMTAB
)
607 ss
->dynsym
= elf_section_by_name(elf
, &ehdr
, &ss
->dynshdr
, ".dynsym",
609 if (ss
->dynshdr
.sh_type
!= SHT_DYNSYM
)
613 ss
->opdsec
= elf_section_by_name(elf
, &ehdr
, &ss
->opdshdr
, ".opd",
615 if (ss
->opdshdr
.sh_type
!= SHT_PROGBITS
)
618 if (dso
->kernel
== DSO_TYPE_USER
) {
620 ss
->adjust_symbols
= (ehdr
.e_type
== ET_EXEC
||
621 ehdr
.e_type
== ET_REL
||
622 is_vdso_map(dso
->short_name
) ||
623 elf_section_by_name(elf
, &ehdr
, &shdr
,
627 ss
->adjust_symbols
= ehdr
.e_type
== ET_EXEC
||
628 ehdr
.e_type
== ET_REL
;
631 ss
->name
= strdup(name
);
650 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
651 * @kmap: kernel maps and relocation reference symbol
653 * This function returns %true if we are dealing with the kernel maps and the
654 * relocation reference symbol has not yet been found. Otherwise %false is
657 static bool ref_reloc_sym_not_found(struct kmap
*kmap
)
659 return kmap
&& kmap
->ref_reloc_sym
&& kmap
->ref_reloc_sym
->name
&&
660 !kmap
->ref_reloc_sym
->unrelocated_addr
;
664 * ref_reloc - kernel relocation offset.
665 * @kmap: kernel maps and relocation reference symbol
667 * This function returns the offset of kernel addresses as determined by using
668 * the relocation reference symbol i.e. if the kernel has not been relocated
669 * then the return value is zero.
671 static u64
ref_reloc(struct kmap
*kmap
)
673 if (kmap
&& kmap
->ref_reloc_sym
&&
674 kmap
->ref_reloc_sym
->unrelocated_addr
)
675 return kmap
->ref_reloc_sym
->addr
-
676 kmap
->ref_reloc_sym
->unrelocated_addr
;
680 int dso__load_sym(struct dso
*dso
, struct map
*map
,
681 struct symsrc
*syms_ss
, struct symsrc
*runtime_ss
,
682 symbol_filter_t filter
, int kmodule
)
684 struct kmap
*kmap
= dso
->kernel
? map__kmap(map
) : NULL
;
685 struct map
*curr_map
= map
;
686 struct dso
*curr_dso
= dso
;
687 Elf_Data
*symstrs
, *secstrs
;
693 Elf_Data
*syms
, *opddata
= NULL
;
695 Elf_Scn
*sec
, *sec_strndx
;
698 bool remap_kernel
= false, adjust_kernel_syms
= false;
700 dso
->symtab_type
= syms_ss
->type
;
701 dso
->rel
= syms_ss
->ehdr
.e_type
== ET_REL
;
704 * Modules may already have symbols from kallsyms, but those symbols
705 * have the wrong values for the dso maps, so remove them.
707 if (kmodule
&& syms_ss
->symtab
)
708 symbols__delete(&dso
->symbols
[map
->type
]);
710 if (!syms_ss
->symtab
) {
711 syms_ss
->symtab
= syms_ss
->dynsym
;
712 syms_ss
->symshdr
= syms_ss
->dynshdr
;
716 ehdr
= syms_ss
->ehdr
;
717 sec
= syms_ss
->symtab
;
718 shdr
= syms_ss
->symshdr
;
720 if (runtime_ss
->opdsec
)
721 opddata
= elf_rawdata(runtime_ss
->opdsec
, NULL
);
723 syms
= elf_getdata(sec
, NULL
);
727 sec
= elf_getscn(elf
, shdr
.sh_link
);
731 symstrs
= elf_getdata(sec
, NULL
);
735 sec_strndx
= elf_getscn(elf
, ehdr
.e_shstrndx
);
736 if (sec_strndx
== NULL
)
739 secstrs
= elf_getdata(sec_strndx
, NULL
);
743 nr_syms
= shdr
.sh_size
/ shdr
.sh_entsize
;
745 memset(&sym
, 0, sizeof(sym
));
748 * The kernel relocation symbol is needed in advance in order to adjust
749 * kernel maps correctly.
751 if (ref_reloc_sym_not_found(kmap
)) {
752 elf_symtab__for_each_symbol(syms
, nr_syms
, idx
, sym
) {
753 const char *elf_name
= elf_sym__name(&sym
, symstrs
);
755 if (strcmp(elf_name
, kmap
->ref_reloc_sym
->name
))
757 kmap
->ref_reloc_sym
->unrelocated_addr
= sym
.st_value
;
758 map
->reloc
= kmap
->ref_reloc_sym
->addr
-
759 kmap
->ref_reloc_sym
->unrelocated_addr
;
764 dso
->adjust_symbols
= runtime_ss
->adjust_symbols
|| ref_reloc(kmap
);
766 * Initial kernel and module mappings do not map to the dso. For
767 * function mappings, flag the fixups.
769 if (map
->type
== MAP__FUNCTION
&& (dso
->kernel
|| kmodule
)) {
771 adjust_kernel_syms
= dso
->adjust_symbols
;
773 elf_symtab__for_each_symbol(syms
, nr_syms
, idx
, sym
) {
775 const char *elf_name
= elf_sym__name(&sym
, symstrs
);
776 char *demangled
= NULL
;
777 int is_label
= elf_sym__is_label(&sym
);
778 const char *section_name
;
779 bool used_opd
= false;
781 if (!is_label
&& !elf_sym__is_a(&sym
, map
->type
))
784 /* Reject ARM ELF "mapping symbols": these aren't unique and
785 * don't identify functions, so will confuse the profile
787 if (ehdr
.e_machine
== EM_ARM
) {
788 if (!strcmp(elf_name
, "$a") ||
789 !strcmp(elf_name
, "$d") ||
790 !strcmp(elf_name
, "$t"))
794 if (runtime_ss
->opdsec
&& sym
.st_shndx
== runtime_ss
->opdidx
) {
795 u32 offset
= sym
.st_value
- syms_ss
->opdshdr
.sh_addr
;
796 u64
*opd
= opddata
->d_buf
+ offset
;
797 sym
.st_value
= DSO__SWAP(dso
, u64
, *opd
);
798 sym
.st_shndx
= elf_addr_to_index(runtime_ss
->elf
,
803 * When loading symbols in a data mapping, ABS symbols (which
804 * has a value of SHN_ABS in its st_shndx) failed at
805 * elf_getscn(). And it marks the loading as a failure so
806 * already loaded symbols cannot be fixed up.
808 * I'm not sure what should be done. Just ignore them for now.
811 if (sym
.st_shndx
== SHN_ABS
)
814 sec
= elf_getscn(runtime_ss
->elf
, sym
.st_shndx
);
818 gelf_getshdr(sec
, &shdr
);
820 if (is_label
&& !elf_sec__is_a(&shdr
, secstrs
, map
->type
))
823 section_name
= elf_sec__name(&shdr
, secstrs
);
825 /* On ARM, symbols for thumb functions have 1 added to
826 * the symbol address as a flag - remove it */
827 if ((ehdr
.e_machine
== EM_ARM
) &&
828 (map
->type
== MAP__FUNCTION
) &&
832 if (dso
->kernel
|| kmodule
) {
833 char dso_name
[PATH_MAX
];
835 /* Adjust symbol to map to file offset */
836 if (adjust_kernel_syms
)
837 sym
.st_value
-= shdr
.sh_addr
- shdr
.sh_offset
;
839 if (strcmp(section_name
,
840 (curr_dso
->short_name
+
841 dso
->short_name_len
)) == 0)
844 if (strcmp(section_name
, ".text") == 0) {
846 * The initial kernel mapping is based on
847 * kallsyms and identity maps. Overwrite it to
848 * map to the kernel dso.
850 if (remap_kernel
&& dso
->kernel
) {
851 remap_kernel
= false;
852 map
->start
= shdr
.sh_addr
+
854 map
->end
= map
->start
+ shdr
.sh_size
;
855 map
->pgoff
= shdr
.sh_offset
;
856 map
->map_ip
= map__map_ip
;
857 map
->unmap_ip
= map__unmap_ip
;
858 /* Ensure maps are correctly ordered */
859 map_groups__remove(kmap
->kmaps
, map
);
860 map_groups__insert(kmap
->kmaps
, map
);
864 * The initial module mapping is based on
865 * /proc/modules mapped to offset zero.
866 * Overwrite it to map to the module dso.
868 if (remap_kernel
&& kmodule
) {
869 remap_kernel
= false;
870 map
->pgoff
= shdr
.sh_offset
;
881 snprintf(dso_name
, sizeof(dso_name
),
882 "%s%s", dso
->short_name
, section_name
);
884 curr_map
= map_groups__find_by_name(kmap
->kmaps
, map
->type
, dso_name
);
885 if (curr_map
== NULL
) {
886 u64 start
= sym
.st_value
;
889 start
+= map
->start
+ shdr
.sh_offset
;
891 curr_dso
= dso__new(dso_name
);
892 if (curr_dso
== NULL
)
894 curr_dso
->kernel
= dso
->kernel
;
895 curr_dso
->long_name
= dso
->long_name
;
896 curr_dso
->long_name_len
= dso
->long_name_len
;
897 curr_map
= map__new2(start
, curr_dso
,
899 if (curr_map
== NULL
) {
900 dso__delete(curr_dso
);
903 if (adjust_kernel_syms
) {
904 curr_map
->start
= shdr
.sh_addr
+
906 curr_map
->end
= curr_map
->start
+
908 curr_map
->pgoff
= shdr
.sh_offset
;
910 curr_map
->map_ip
= identity__map_ip
;
911 curr_map
->unmap_ip
= identity__map_ip
;
913 curr_dso
->symtab_type
= dso
->symtab_type
;
914 map_groups__insert(kmap
->kmaps
, curr_map
);
915 dsos__add(&dso
->node
, curr_dso
);
916 dso__set_loaded(curr_dso
, map
->type
);
918 curr_dso
= curr_map
->dso
;
923 if ((used_opd
&& runtime_ss
->adjust_symbols
)
924 || (!used_opd
&& syms_ss
->adjust_symbols
)) {
925 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64
" "
926 "sh_addr: %#" PRIx64
" sh_offset: %#" PRIx64
"\n", __func__
,
927 (u64
)sym
.st_value
, (u64
)shdr
.sh_addr
,
928 (u64
)shdr
.sh_offset
);
929 sym
.st_value
-= shdr
.sh_addr
- shdr
.sh_offset
;
933 * We need to figure out if the object was created from C++ sources
934 * DWARF DW_compile_unit has this, but we don't always have access
937 if (symbol_conf
.demangle
) {
938 demangled
= bfd_demangle(NULL
, elf_name
,
939 DMGL_PARAMS
| DMGL_ANSI
);
940 if (demangled
!= NULL
)
941 elf_name
= demangled
;
943 f
= symbol__new(sym
.st_value
, sym
.st_size
,
944 GELF_ST_BIND(sym
.st_info
), elf_name
);
949 if (filter
&& filter(curr_map
, f
))
952 symbols__insert(&curr_dso
->symbols
[curr_map
->type
], f
);
958 * For misannotated, zeroed, ASM function sizes.
961 symbols__fixup_duplicate(&dso
->symbols
[map
->type
]);
962 symbols__fixup_end(&dso
->symbols
[map
->type
]);
965 * We need to fixup this here too because we create new
966 * maps here, for things like vsyscall sections.
968 __map_groups__fixup_end(kmap
->kmaps
, map
->type
);
976 static int elf_read_maps(Elf
*elf
, bool exe
, mapfn_t mapfn
, void *data
)
983 if (elf_getphdrnum(elf
, &phdrnum
))
986 for (i
= 0; i
< phdrnum
; i
++) {
987 if (gelf_getphdr(elf
, i
, &phdr
) == NULL
)
989 if (phdr
.p_type
!= PT_LOAD
)
992 if (!(phdr
.p_flags
& PF_X
))
995 if (!(phdr
.p_flags
& PF_R
))
998 sz
= min(phdr
.p_memsz
, phdr
.p_filesz
);
1001 err
= mapfn(phdr
.p_vaddr
, sz
, phdr
.p_offset
, data
);
1008 int file__read_maps(int fd
, bool exe
, mapfn_t mapfn
, void *data
,
1014 elf
= elf_begin(fd
, PERF_ELF_C_READ_MMAP
, NULL
);
1019 *is_64_bit
= (gelf_getclass(elf
) == ELFCLASS64
);
1021 err
= elf_read_maps(elf
, exe
, mapfn
, data
);
1027 static int copy_bytes(int from
, off_t from_offs
, int to
, off_t to_offs
, u64 len
)
1032 char *buf
= malloc(page_size
);
1037 if (lseek(to
, to_offs
, SEEK_SET
) != to_offs
)
1040 if (lseek(from
, from_offs
, SEEK_SET
) != from_offs
)
1047 /* Use read because mmap won't work on proc files */
1048 r
= read(from
, buf
, n
);
1054 r
= write(to
, buf
, n
);
1075 static int kcore__open(struct kcore
*kcore
, const char *filename
)
1079 kcore
->fd
= open(filename
, O_RDONLY
);
1080 if (kcore
->fd
== -1)
1083 kcore
->elf
= elf_begin(kcore
->fd
, ELF_C_READ
, NULL
);
1087 kcore
->elfclass
= gelf_getclass(kcore
->elf
);
1088 if (kcore
->elfclass
== ELFCLASSNONE
)
1091 ehdr
= gelf_getehdr(kcore
->elf
, &kcore
->ehdr
);
1098 elf_end(kcore
->elf
);
1104 static int kcore__init(struct kcore
*kcore
, char *filename
, int elfclass
,
1109 kcore
->elfclass
= elfclass
;
1112 kcore
->fd
= mkstemp(filename
);
1114 kcore
->fd
= open(filename
, O_WRONLY
| O_CREAT
| O_EXCL
, 0400);
1115 if (kcore
->fd
== -1)
1118 kcore
->elf
= elf_begin(kcore
->fd
, ELF_C_WRITE
, NULL
);
1122 if (!gelf_newehdr(kcore
->elf
, elfclass
))
1125 ehdr
= gelf_getehdr(kcore
->elf
, &kcore
->ehdr
);
1132 elf_end(kcore
->elf
);
1139 static void kcore__close(struct kcore
*kcore
)
1141 elf_end(kcore
->elf
);
1145 static int kcore__copy_hdr(struct kcore
*from
, struct kcore
*to
, size_t count
)
1147 GElf_Ehdr
*ehdr
= &to
->ehdr
;
1148 GElf_Ehdr
*kehdr
= &from
->ehdr
;
1150 memcpy(ehdr
->e_ident
, kehdr
->e_ident
, EI_NIDENT
);
1151 ehdr
->e_type
= kehdr
->e_type
;
1152 ehdr
->e_machine
= kehdr
->e_machine
;
1153 ehdr
->e_version
= kehdr
->e_version
;
1156 ehdr
->e_flags
= kehdr
->e_flags
;
1157 ehdr
->e_phnum
= count
;
1158 ehdr
->e_shentsize
= 0;
1160 ehdr
->e_shstrndx
= 0;
1162 if (from
->elfclass
== ELFCLASS32
) {
1163 ehdr
->e_phoff
= sizeof(Elf32_Ehdr
);
1164 ehdr
->e_ehsize
= sizeof(Elf32_Ehdr
);
1165 ehdr
->e_phentsize
= sizeof(Elf32_Phdr
);
1167 ehdr
->e_phoff
= sizeof(Elf64_Ehdr
);
1168 ehdr
->e_ehsize
= sizeof(Elf64_Ehdr
);
1169 ehdr
->e_phentsize
= sizeof(Elf64_Phdr
);
1172 if (!gelf_update_ehdr(to
->elf
, ehdr
))
1175 if (!gelf_newphdr(to
->elf
, count
))
1181 static int kcore__add_phdr(struct kcore
*kcore
, int idx
, off_t offset
,
1187 phdr
= gelf_getphdr(kcore
->elf
, idx
, &gphdr
);
1191 phdr
->p_type
= PT_LOAD
;
1192 phdr
->p_flags
= PF_R
| PF_W
| PF_X
;
1193 phdr
->p_offset
= offset
;
1194 phdr
->p_vaddr
= addr
;
1196 phdr
->p_filesz
= len
;
1197 phdr
->p_memsz
= len
;
1198 phdr
->p_align
= page_size
;
1200 if (!gelf_update_phdr(kcore
->elf
, idx
, phdr
))
1206 static off_t
kcore__write(struct kcore
*kcore
)
1208 return elf_update(kcore
->elf
, ELF_C_WRITE
);
1217 struct kcore_copy_info
{
1223 u64 last_module_symbol
;
1224 struct phdr_data kernel_map
;
1225 struct phdr_data modules_map
;
1228 static int kcore_copy__process_kallsyms(void *arg
, const char *name
, char type
,
1231 struct kcore_copy_info
*kci
= arg
;
1233 if (!symbol_type__is_a(type
, MAP__FUNCTION
))
1236 if (strchr(name
, '[')) {
1237 if (start
> kci
->last_module_symbol
)
1238 kci
->last_module_symbol
= start
;
1242 if (!kci
->first_symbol
|| start
< kci
->first_symbol
)
1243 kci
->first_symbol
= start
;
1245 if (!kci
->last_symbol
|| start
> kci
->last_symbol
)
1246 kci
->last_symbol
= start
;
1248 if (!strcmp(name
, "_stext")) {
1253 if (!strcmp(name
, "_etext")) {
1261 static int kcore_copy__parse_kallsyms(struct kcore_copy_info
*kci
,
1264 char kallsyms_filename
[PATH_MAX
];
1266 scnprintf(kallsyms_filename
, PATH_MAX
, "%s/kallsyms", dir
);
1268 if (symbol__restricted_filename(kallsyms_filename
, "/proc/kallsyms"))
1271 if (kallsyms__parse(kallsyms_filename
, kci
,
1272 kcore_copy__process_kallsyms
) < 0)
1278 static int kcore_copy__process_modules(void *arg
,
1279 const char *name __maybe_unused
,
1282 struct kcore_copy_info
*kci
= arg
;
1284 if (!kci
->first_module
|| start
< kci
->first_module
)
1285 kci
->first_module
= start
;
1290 static int kcore_copy__parse_modules(struct kcore_copy_info
*kci
,
1293 char modules_filename
[PATH_MAX
];
1295 scnprintf(modules_filename
, PATH_MAX
, "%s/modules", dir
);
1297 if (symbol__restricted_filename(modules_filename
, "/proc/modules"))
1300 if (modules__parse(modules_filename
, kci
,
1301 kcore_copy__process_modules
) < 0)
1307 static void kcore_copy__map(struct phdr_data
*p
, u64 start
, u64 end
, u64 pgoff
,
1310 if (p
->addr
|| s
< start
|| s
>= end
)
1314 p
->offset
= (s
- start
) + pgoff
;
1315 p
->len
= e
< end
? e
- s
: end
- s
;
1318 static int kcore_copy__read_map(u64 start
, u64 len
, u64 pgoff
, void *data
)
1320 struct kcore_copy_info
*kci
= data
;
1321 u64 end
= start
+ len
;
1323 kcore_copy__map(&kci
->kernel_map
, start
, end
, pgoff
, kci
->stext
,
1326 kcore_copy__map(&kci
->modules_map
, start
, end
, pgoff
, kci
->first_module
,
1327 kci
->last_module_symbol
);
1332 static int kcore_copy__read_maps(struct kcore_copy_info
*kci
, Elf
*elf
)
1334 if (elf_read_maps(elf
, true, kcore_copy__read_map
, kci
) < 0)
1340 static int kcore_copy__calc_maps(struct kcore_copy_info
*kci
, const char *dir
,
1343 if (kcore_copy__parse_kallsyms(kci
, dir
))
1346 if (kcore_copy__parse_modules(kci
, dir
))
1350 kci
->stext
= round_down(kci
->stext
, page_size
);
1352 kci
->stext
= round_down(kci
->first_symbol
, page_size
);
1355 kci
->etext
= round_up(kci
->etext
, page_size
);
1356 } else if (kci
->last_symbol
) {
1357 kci
->etext
= round_up(kci
->last_symbol
, page_size
);
1358 kci
->etext
+= page_size
;
1361 kci
->first_module
= round_down(kci
->first_module
, page_size
);
1363 if (kci
->last_module_symbol
) {
1364 kci
->last_module_symbol
= round_up(kci
->last_module_symbol
,
1366 kci
->last_module_symbol
+= page_size
;
1369 if (!kci
->stext
|| !kci
->etext
)
1372 if (kci
->first_module
&& !kci
->last_module_symbol
)
1375 return kcore_copy__read_maps(kci
, elf
);
1378 static int kcore_copy__copy_file(const char *from_dir
, const char *to_dir
,
1381 char from_filename
[PATH_MAX
];
1382 char to_filename
[PATH_MAX
];
1384 scnprintf(from_filename
, PATH_MAX
, "%s/%s", from_dir
, name
);
1385 scnprintf(to_filename
, PATH_MAX
, "%s/%s", to_dir
, name
);
1387 return copyfile_mode(from_filename
, to_filename
, 0400);
1390 static int kcore_copy__unlink(const char *dir
, const char *name
)
1392 char filename
[PATH_MAX
];
1394 scnprintf(filename
, PATH_MAX
, "%s/%s", dir
, name
);
1396 return unlink(filename
);
1399 static int kcore_copy__compare_fds(int from
, int to
)
1407 buf_from
= malloc(page_size
);
1408 buf_to
= malloc(page_size
);
1409 if (!buf_from
|| !buf_to
)
1413 /* Use read because mmap won't work on proc files */
1414 ret
= read(from
, buf_from
, page_size
);
1423 if (readn(to
, buf_to
, len
) != (int)len
)
1426 if (memcmp(buf_from
, buf_to
, len
))
1437 static int kcore_copy__compare_files(const char *from_filename
,
1438 const char *to_filename
)
1440 int from
, to
, err
= -1;
1442 from
= open(from_filename
, O_RDONLY
);
1446 to
= open(to_filename
, O_RDONLY
);
1448 goto out_close_from
;
1450 err
= kcore_copy__compare_fds(from
, to
);
1458 static int kcore_copy__compare_file(const char *from_dir
, const char *to_dir
,
1461 char from_filename
[PATH_MAX
];
1462 char to_filename
[PATH_MAX
];
1464 scnprintf(from_filename
, PATH_MAX
, "%s/%s", from_dir
, name
);
1465 scnprintf(to_filename
, PATH_MAX
, "%s/%s", to_dir
, name
);
1467 return kcore_copy__compare_files(from_filename
, to_filename
);
1471 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1472 * @from_dir: from directory
1473 * @to_dir: to directory
1475 * This function copies kallsyms, modules and kcore files from one directory to
1476 * another. kallsyms and modules are copied entirely. Only code segments are
1477 * copied from kcore. It is assumed that two segments suffice: one for the
1478 * kernel proper and one for all the modules. The code segments are determined
1479 * from kallsyms and modules files. The kernel map starts at _stext or the
1480 * lowest function symbol, and ends at _etext or the highest function symbol.
1481 * The module map starts at the lowest module address and ends at the highest
1482 * module symbol. Start addresses are rounded down to the nearest page. End
1483 * addresses are rounded up to the nearest page. An extra page is added to the
1484 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1485 * symbol too. Because it contains only code sections, the resulting kcore is
1486 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1487 * is not the same for the kernel map and the modules map. That happens because
1488 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1489 * kallsyms and modules files are compared with their copies to check that
1490 * modules have not been loaded or unloaded while the copies were taking place.
1492 * Return: %0 on success, %-1 on failure.
1494 int kcore_copy(const char *from_dir
, const char *to_dir
)
1497 struct kcore extract
;
1499 int idx
= 0, err
= -1;
1500 off_t offset
= page_size
, sz
, modules_offset
= 0;
1501 struct kcore_copy_info kci
= { .stext
= 0, };
1502 char kcore_filename
[PATH_MAX
];
1503 char extract_filename
[PATH_MAX
];
1505 if (kcore_copy__copy_file(from_dir
, to_dir
, "kallsyms"))
1508 if (kcore_copy__copy_file(from_dir
, to_dir
, "modules"))
1509 goto out_unlink_kallsyms
;
1511 scnprintf(kcore_filename
, PATH_MAX
, "%s/kcore", from_dir
);
1512 scnprintf(extract_filename
, PATH_MAX
, "%s/kcore", to_dir
);
1514 if (kcore__open(&kcore
, kcore_filename
))
1515 goto out_unlink_modules
;
1517 if (kcore_copy__calc_maps(&kci
, from_dir
, kcore
.elf
))
1518 goto out_kcore_close
;
1520 if (kcore__init(&extract
, extract_filename
, kcore
.elfclass
, false))
1521 goto out_kcore_close
;
1523 if (!kci
.modules_map
.addr
)
1526 if (kcore__copy_hdr(&kcore
, &extract
, count
))
1527 goto out_extract_close
;
1529 if (kcore__add_phdr(&extract
, idx
++, offset
, kci
.kernel_map
.addr
,
1530 kci
.kernel_map
.len
))
1531 goto out_extract_close
;
1533 if (kci
.modules_map
.addr
) {
1534 modules_offset
= offset
+ kci
.kernel_map
.len
;
1535 if (kcore__add_phdr(&extract
, idx
, modules_offset
,
1536 kci
.modules_map
.addr
, kci
.modules_map
.len
))
1537 goto out_extract_close
;
1540 sz
= kcore__write(&extract
);
1541 if (sz
< 0 || sz
> offset
)
1542 goto out_extract_close
;
1544 if (copy_bytes(kcore
.fd
, kci
.kernel_map
.offset
, extract
.fd
, offset
,
1545 kci
.kernel_map
.len
))
1546 goto out_extract_close
;
1548 if (modules_offset
&& copy_bytes(kcore
.fd
, kci
.modules_map
.offset
,
1549 extract
.fd
, modules_offset
,
1550 kci
.modules_map
.len
))
1551 goto out_extract_close
;
1553 if (kcore_copy__compare_file(from_dir
, to_dir
, "modules"))
1554 goto out_extract_close
;
1556 if (kcore_copy__compare_file(from_dir
, to_dir
, "kallsyms"))
1557 goto out_extract_close
;
1562 kcore__close(&extract
);
1564 unlink(extract_filename
);
1566 kcore__close(&kcore
);
1569 kcore_copy__unlink(to_dir
, "modules");
1570 out_unlink_kallsyms
:
1572 kcore_copy__unlink(to_dir
, "kallsyms");
1577 int kcore_extract__create(struct kcore_extract
*kce
)
1580 struct kcore extract
;
1582 int idx
= 0, err
= -1;
1583 off_t offset
= page_size
, sz
;
1585 if (kcore__open(&kcore
, kce
->kcore_filename
))
1588 strcpy(kce
->extract_filename
, PERF_KCORE_EXTRACT
);
1589 if (kcore__init(&extract
, kce
->extract_filename
, kcore
.elfclass
, true))
1590 goto out_kcore_close
;
1592 if (kcore__copy_hdr(&kcore
, &extract
, count
))
1593 goto out_extract_close
;
1595 if (kcore__add_phdr(&extract
, idx
, offset
, kce
->addr
, kce
->len
))
1596 goto out_extract_close
;
1598 sz
= kcore__write(&extract
);
1599 if (sz
< 0 || sz
> offset
)
1600 goto out_extract_close
;
1602 if (copy_bytes(kcore
.fd
, kce
->offs
, extract
.fd
, offset
, kce
->len
))
1603 goto out_extract_close
;
1608 kcore__close(&extract
);
1610 unlink(kce
->extract_filename
);
1612 kcore__close(&kcore
);
1617 void kcore_extract__delete(struct kcore_extract
*kce
)
1619 unlink(kce
->extract_filename
);
1622 void symbol__elf_init(void)
1624 elf_version(EV_CURRENT
);