2 * Copyright (C) 2015 Antoine Busque <abusque@efficios.com>
3 * Copyright (C) 2017 Francis Deslauriers <francis.deslauriers@efficios.com>
4 * Copyright (C) 2017 Erica Bugden <erica.bugden@efficios.com>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 #include <common/compat/endian.h>
22 #include <common/error.h>
23 #include <common/lttng-elf.h>
24 #include <common/macros.h>
25 #include <common/readwrite.h>
32 #include <sys/types.h>
38 #define TEXT_SECTION_NAME ".text"
39 #define SYMBOL_TAB_SECTION_NAME ".symtab"
40 #define STRING_TAB_SECTION_NAME ".strtab"
41 #define DYNAMIC_SYMBOL_TAB_SECTION_NAME ".dynsym"
42 #define DYNAMIC_STRING_TAB_SECTION_NAME ".dynstr"
43 #define NOTE_STAPSDT_SECTION_NAME ".note.stapsdt"
44 #define NOTE_STAPSDT_NAME "stapsdt"
45 #define NOTE_STAPSDT_TYPE 3
47 #if BYTE_ORDER == LITTLE_ENDIAN
48 #define NATIVE_ELF_ENDIANNESS ELFDATA2LSB
50 #define NATIVE_ELF_ENDIANNESS ELFDATA2MSB
53 #define next_4bytes_boundary(x) (typeof(x)) ((((uint64_t)x) + 3) & ~0x03)
57 switch (sizeof(x)) { \
74 #define bswap_shdr(shdr) \
76 bswap((shdr).sh_name); \
77 bswap((shdr).sh_type); \
78 bswap((shdr).sh_flags); \
79 bswap((shdr).sh_addr); \
80 bswap((shdr).sh_offset); \
81 bswap((shdr).sh_size); \
82 bswap((shdr).sh_link); \
83 bswap((shdr).sh_info); \
84 bswap((shdr).sh_addralign); \
85 bswap((shdr).sh_entsize); \
88 #define bswap_ehdr(ehdr) \
90 bswap((ehdr).e_type); \
91 bswap((ehdr).e_machine); \
92 bswap((ehdr).e_version); \
93 bswap((ehdr).e_entry); \
94 bswap((ehdr).e_phoff); \
95 bswap((ehdr).e_shoff); \
96 bswap((ehdr).e_flags); \
97 bswap((ehdr).e_ehsize); \
98 bswap((ehdr).e_phentsize); \
99 bswap((ehdr).e_phnum); \
100 bswap((ehdr).e_shentsize); \
101 bswap((ehdr).e_shnum); \
102 bswap((ehdr).e_shstrndx); \
105 #define copy_shdr(src_shdr, dst_shdr) \
107 (dst_shdr).sh_name = (src_shdr).sh_name; \
108 (dst_shdr).sh_type = (src_shdr).sh_type; \
109 (dst_shdr).sh_flags = (src_shdr).sh_flags; \
110 (dst_shdr).sh_addr = (src_shdr).sh_addr; \
111 (dst_shdr).sh_offset = (src_shdr).sh_offset; \
112 (dst_shdr).sh_size = (src_shdr).sh_size; \
113 (dst_shdr).sh_link = (src_shdr).sh_link; \
114 (dst_shdr).sh_info = (src_shdr).sh_info; \
115 (dst_shdr).sh_addralign = (src_shdr).sh_addralign; \
116 (dst_shdr).sh_entsize = (src_shdr).sh_entsize; \
119 #define copy_ehdr(src_ehdr, dst_ehdr) \
121 (dst_ehdr).e_type = (src_ehdr).e_type; \
122 (dst_ehdr).e_machine = (src_ehdr).e_machine; \
123 (dst_ehdr).e_version = (src_ehdr).e_version; \
124 (dst_ehdr).e_entry = (src_ehdr).e_entry; \
125 (dst_ehdr).e_phoff = (src_ehdr).e_phoff; \
126 (dst_ehdr).e_shoff = (src_ehdr).e_shoff; \
127 (dst_ehdr).e_flags = (src_ehdr).e_flags; \
128 (dst_ehdr).e_ehsize = (src_ehdr).e_ehsize; \
129 (dst_ehdr).e_phentsize = (src_ehdr).e_phentsize; \
130 (dst_ehdr).e_phnum = (src_ehdr).e_phnum; \
131 (dst_ehdr).e_shentsize = (src_ehdr).e_shentsize; \
132 (dst_ehdr).e_shnum = (src_ehdr).e_shnum; \
133 (dst_ehdr).e_shstrndx = (src_ehdr).e_shstrndx; \
136 #define copy_sym(src_sym, dst_sym) \
138 dst_sym.st_name = src_sym.st_name; \
139 dst_sym.st_info = src_sym.st_info; \
140 dst_sym.st_other = src_sym.st_other; \
141 dst_sym.st_shndx = src_sym.st_shndx; \
142 dst_sym.st_value = src_sym.st_value; \
143 dst_sym.st_size = src_sym.st_size; \
146 /* Both 32bit and 64bit use the same 1 byte field for type. (See elf.h) */
147 #define ELF_ST_TYPE(val) ELF32_ST_TYPE(val)
149 struct lttng_elf_ehdr
{
158 uint16_t e_phentsize
;
160 uint16_t e_shentsize
;
165 struct lttng_elf_shdr
{
174 uint64_t sh_addralign
;
179 * This struct can hold both 32bit and 64bit symbol description. It's used with
180 * the copy_sym() macro. Using this abstraction, we can use the same code for
183 struct lttng_elf_sym
{
196 /* Offset in bytes to start of section names string table. */
197 off_t section_names_offset
;
198 /* Size in bytes of section names string table. */
199 size_t section_names_size
;
200 struct lttng_elf_ehdr
*ehdr
;
204 int is_elf_32_bit(struct lttng_elf
*elf
)
206 return elf
->bitness
== ELFCLASS32
;
210 int is_elf_native_endian(struct lttng_elf
*elf
)
212 return elf
->endianness
== NATIVE_ELF_ENDIANNESS
;
216 int populate_section_header(struct lttng_elf
* elf
, struct lttng_elf_shdr
*shdr
,
222 /* Compute the offset of the section in the file */
223 offset
= (off_t
) elf
->ehdr
->e_shoff
224 + (off_t
) index
* elf
->ehdr
->e_shentsize
;
226 if (lseek(elf
->fd
, offset
, SEEK_SET
) < 0) {
227 PERROR("Error seeking to the beginning of ELF section header");
232 if (is_elf_32_bit(elf
)) {
235 if (lttng_read(elf
->fd
, &elf_shdr
, sizeof(elf_shdr
)) < sizeof(elf_shdr
)) {
236 PERROR("Error reading ELF section header");
240 if (!is_elf_native_endian(elf
)) {
241 bswap_shdr(elf_shdr
);
243 copy_shdr(elf_shdr
, *shdr
);
247 if (lttng_read(elf
->fd
, &elf_shdr
, sizeof(elf_shdr
)) < sizeof(elf_shdr
)) {
248 PERROR("Error reading ELF section header");
252 if (!is_elf_native_endian(elf
)) {
253 bswap_shdr(elf_shdr
);
255 copy_shdr(elf_shdr
, *shdr
);
263 int populate_elf_header(struct lttng_elf
*elf
)
268 * Move the read pointer back to the beginning to read the full header
269 * and copy it in our structure.
271 if (lseek(elf
->fd
, 0, SEEK_SET
) < 0) {
272 PERROR("Error seeking to the beginning of the file");
278 * Use macros to set fields in the ELF header struct for both 32bit and
281 if (is_elf_32_bit(elf
)) {
284 if (lttng_read(elf
->fd
, &elf_ehdr
, sizeof(elf_ehdr
)) < sizeof(elf_ehdr
)) {
288 if (!is_elf_native_endian(elf
)) {
289 bswap_ehdr(elf_ehdr
);
291 copy_ehdr(elf_ehdr
, *(elf
->ehdr
));
295 if (lttng_read(elf
->fd
, &elf_ehdr
, sizeof(elf_ehdr
)) < sizeof(elf_ehdr
)) {
299 if (!is_elf_native_endian(elf
)) {
300 bswap_ehdr(elf_ehdr
);
302 copy_ehdr(elf_ehdr
, *(elf
->ehdr
));
309 * Retrieve the nth (where n is the `index` argument) shdr (section
310 * header) from the given elf instance.
312 * A pointer to the shdr is returned on success, NULL on failure.
315 struct lttng_elf_shdr
*lttng_elf_get_section_hdr(struct lttng_elf
*elf
,
318 struct lttng_elf_shdr
*section_header
= NULL
;
325 if (index
>= elf
->ehdr
->e_shnum
) {
329 section_header
= zmalloc(sizeof(struct lttng_elf_shdr
));
330 if (!section_header
) {
334 ret
= populate_section_header(elf
, section_header
, index
);
336 DBG("Error populating section header.");
339 return section_header
;
342 free(section_header
);
347 * Lookup a section's name from a given offset (usually from an shdr's
348 * sh_name value) in bytes relative to the beginning of the section
349 * names string table.
351 * If no name is found, NULL is returned.
354 char *lttng_elf_get_section_name(struct lttng_elf
*elf
, off_t offset
)
357 size_t name_length
= 0, to_read
; /* name_length does not include \0 */
363 if (offset
>= elf
->section_names_size
) {
367 if (lseek(elf
->fd
, elf
->section_names_offset
+ offset
, SEEK_SET
) < 0) {
368 PERROR("Error seeking to the beginning of ELF string table section");
372 to_read
= elf
->section_names_size
- offset
;
374 /* Find first \0 after or at current location, remember name_length. */
383 read_len
= lttng_read(elf
->fd
, buf
, min_t(size_t, BUF_LEN
, to_read
));
385 PERROR("Error reading ELF string table section");
388 for (i
= 0; i
< read_len
; i
++) {
389 if (buf
[i
] == '\0') {
394 name_length
+= read_len
;
399 * We found the length of the section name, now seek back to the
400 * beginning of the name and copy it in the newly allocated buffer.
402 name
= zmalloc(sizeof(char) * (name_length
+ 1)); /* + 1 for \0 */
404 PERROR("Error allocating ELF section name buffer");
407 if (lseek(elf
->fd
, elf
->section_names_offset
+ offset
, SEEK_SET
) < 0) {
408 PERROR("Error seeking to the offset of the ELF section name");
411 if (lttng_read(elf
->fd
, name
, name_length
+ 1) < name_length
+ 1) {
412 PERROR("Error reading the ELF section name");
424 int lttng_elf_validate_and_populate(struct lttng_elf
*elf
)
427 uint8_t e_ident
[EI_NIDENT
];
428 uint8_t *magic_number
= NULL
;
433 ret
= LTTNG_ERR_ELF_PARSING
;
438 * First read the magic number, endianness and version to later populate
439 * the ELF header with the correct endianness and bitness.
443 if (lseek(elf
->fd
, 0, SEEK_SET
) < 0) {
444 PERROR("Error seeking the beginning of ELF file");
445 ret
= LTTNG_ERR_ELF_PARSING
;
448 ret
= lttng_read(elf
->fd
, e_ident
, EI_NIDENT
);
449 if (ret
< EI_NIDENT
) {
450 DBG("Error reading the ELF identification fields");
452 PERROR("Error reading the ELF identification fields");
454 ret
= LTTNG_ERR_ELF_PARSING
;
459 * Copy fields used to check that the target file is in fact a valid ELF
462 elf
->bitness
= e_ident
[EI_CLASS
];
463 elf
->endianness
= e_ident
[EI_DATA
];
464 version
= e_ident
[EI_VERSION
];
465 magic_number
= &e_ident
[EI_MAG0
];
468 * Check the magic number.
470 if (memcmp(magic_number
, ELFMAG
, SELFMAG
) != 0) {
471 DBG("Error check ELF magic number.");
472 ret
= LTTNG_ERR_ELF_PARSING
;
477 * Check the bitness is either ELFCLASS32 or ELFCLASS64.
479 if (elf
->bitness
<= ELFCLASSNONE
|| elf
->bitness
>= ELFCLASSNUM
) {
480 DBG("ELF class error.");
481 ret
= LTTNG_ERR_ELF_PARSING
;
486 * Check the endianness is either ELFDATA2LSB or ELFDATA2MSB.
488 if (elf
->endianness
<= ELFDATANONE
|| elf
->endianness
>= ELFDATANUM
) {
489 DBG("ELF endianness error.");
490 ret
= LTTNG_ERR_ELF_PARSING
;
495 * Check the version is ELF_CURRENT.
497 if (version
<= EV_NONE
|| version
>= EV_NUM
) {
498 DBG("Wrong ELF version.");
499 ret
= LTTNG_ERR_ELF_PARSING
;
503 elf
->ehdr
= zmalloc(sizeof(struct lttng_elf_ehdr
));
505 PERROR("Error allocation buffer for ELF header");
506 ret
= LTTNG_ERR_NOMEM
;
511 * Copy the content of the elf header.
513 ret
= populate_elf_header(elf
);
515 DBG("Error reading ELF header,");
529 * Create an instance of lttng_elf for the ELF file located at
532 * Return a pointer to the instance on success, NULL on failure.
535 struct lttng_elf
*lttng_elf_create(int fd
)
537 struct lttng_elf_shdr
*section_names_shdr
;
538 struct lttng_elf
*elf
= NULL
;
545 elf
= zmalloc(sizeof(struct lttng_elf
));
547 PERROR("Error allocating struct lttng_elf");
553 PERROR("Error duplicating file descriptor to binary");
557 ret
= lttng_elf_validate_and_populate(elf
);
562 section_names_shdr
= lttng_elf_get_section_hdr(elf
, elf
->ehdr
->e_shstrndx
);
563 if (!section_names_shdr
) {
567 elf
->section_names_offset
= section_names_shdr
->sh_offset
;
568 elf
->section_names_size
= section_names_shdr
->sh_size
;
570 free(section_names_shdr
);
579 if (close(elf
->fd
)) {
580 PERROR("Error closing file descriptor in error path");
590 * Destroy the given lttng_elf instance.
593 void lttng_elf_destroy(struct lttng_elf
*elf
)
600 if (close(elf
->fd
)) {
601 PERROR("Error closing file description in error path");
608 int lttng_elf_get_section_hdr_by_name(struct lttng_elf
*elf
,
609 const char *section_name
, struct lttng_elf_shdr
**section_hdr
)
612 char *curr_section_name
;
613 for (i
= 0; i
< elf
->ehdr
->e_shnum
; ++i
) {
614 *section_hdr
= lttng_elf_get_section_hdr(elf
, i
);
615 curr_section_name
= lttng_elf_get_section_name(elf
,
616 (*section_hdr
)->sh_name
);
618 if (!curr_section_name
) {
621 if (strcmp(curr_section_name
, section_name
) == 0) {
625 return LTTNG_ERR_ELF_PARSING
;
629 char *lttng_elf_get_section_data(struct lttng_elf
*elf
,
630 struct lttng_elf_shdr
*shdr
)
633 off_t section_offset
;
640 section_offset
= shdr
->sh_offset
;
641 if (lseek(elf
->fd
, section_offset
, SEEK_SET
) < 0) {
642 PERROR("Error seeking to section offset");
646 data
= zmalloc(shdr
->sh_size
);
648 PERROR("Error allocating buffer for ELF section data");
651 ret
= lttng_read(elf
->fd
, data
, shdr
->sh_size
);
653 PERROR("Error reading ELF section data");
666 * Convert the virtual address in a binary's mapping to the offset of
667 * the corresponding instruction in the binary file.
668 * This function assumes the address is in the text section.
670 * Returns the offset on success or non-zero in case of failure.
673 int lttng_elf_convert_addr_in_text_to_offset(struct lttng_elf
*elf_handle
,
674 size_t addr
, uint64_t *offset
)
677 off_t text_section_offset
;
678 off_t text_section_addr_beg
;
679 off_t text_section_addr_end
;
680 off_t offset_in_section
;
681 struct lttng_elf_shdr
*text_section_hdr
= NULL
;
684 DBG("Invalid ELF handle.");
685 ret
= LTTNG_ERR_ELF_PARSING
;
689 /* Get a pointer to the .text section header. */
690 ret
= lttng_elf_get_section_hdr_by_name(elf_handle
,
691 TEXT_SECTION_NAME
, &text_section_hdr
);
693 DBG("Text section not found in binary.");
694 ret
= LTTNG_ERR_ELF_PARSING
;
698 text_section_offset
= text_section_hdr
->sh_offset
;
699 text_section_addr_beg
= text_section_hdr
->sh_addr
;
700 text_section_addr_end
= text_section_addr_beg
+ text_section_hdr
->sh_size
;
703 * Verify that the address is within the .text section boundaries.
705 if (addr
< text_section_addr_beg
|| addr
> text_section_addr_end
) {
706 DBG("Address found is outside of the .text section addr=0x%zx, "
707 ".text section=[0x%jd - 0x%jd].", addr
, (intmax_t)text_section_addr_beg
,
708 (intmax_t)text_section_addr_end
);
709 ret
= LTTNG_ERR_ELF_PARSING
;
713 offset_in_section
= addr
- text_section_addr_beg
;
716 * Add the target offset in the text section to the offset of this text
717 * section from the beginning of the binary file.
719 *offset
= text_section_offset
+ offset_in_section
;
726 * Compute the offset of a symbol from the begining of the ELF binary.
728 * On success, returns 0 offset parameter is set to the computed value
729 * On failure, returns -1.
731 int lttng_elf_get_symbol_offset(int fd
, char *symbol
, uint64_t *offset
)
738 char *curr_sym_str
= NULL
;
739 char *symbol_table_data
= NULL
;
740 char *string_table_data
= NULL
;
741 char *string_table_name
= NULL
;
742 struct lttng_elf_shdr
*symtab_hdr
= NULL
;
743 struct lttng_elf_shdr
*strtab_hdr
= NULL
;
744 struct lttng_elf
*elf
= NULL
;
746 if (!symbol
|| !offset
) {
747 ret
= LTTNG_ERR_ELF_PARSING
;
751 elf
= lttng_elf_create(fd
);
753 ret
= LTTNG_ERR_ELF_PARSING
;
758 * The .symtab section might not exist on stripped binaries.
759 * Try to get the symbol table section header first. If it's absent,
760 * try to get the dynamic symbol table. All symbols in the dynamic
761 * symbol tab are in the (normal) symbol table if it exists.
763 ret
= lttng_elf_get_section_hdr_by_name(elf
, SYMBOL_TAB_SECTION_NAME
,
766 DBG("Cannot get ELF Symbol Table section. Trying to get ELF Dynamic Symbol Table section.");
767 /* Get the dynamic symbol table section header. */
768 ret
= lttng_elf_get_section_hdr_by_name(elf
, DYNAMIC_SYMBOL_TAB_SECTION_NAME
,
771 DBG("Cannot get ELF Symbol Table nor Dynamic Symbol Table sections.");
772 ret
= LTTNG_ERR_ELF_PARSING
;
775 string_table_name
= DYNAMIC_STRING_TAB_SECTION_NAME
;
777 string_table_name
= STRING_TAB_SECTION_NAME
;
780 /* Get the data associated with the symbol table section. */
781 symbol_table_data
= lttng_elf_get_section_data(elf
, symtab_hdr
);
782 if (symbol_table_data
== NULL
) {
783 DBG("Cannot get ELF Symbol Table data.");
784 ret
= LTTNG_ERR_ELF_PARSING
;
788 /* Get the string table section header. */
789 ret
= lttng_elf_get_section_hdr_by_name(elf
, string_table_name
,
792 DBG("Cannot get ELF string table section.");
793 goto free_symbol_table_data
;
796 /* Get the data associated with the string table section. */
797 string_table_data
= lttng_elf_get_section_data(elf
, strtab_hdr
);
798 if (string_table_data
== NULL
) {
799 DBG("Cannot get ELF string table section data.");
800 ret
= LTTNG_ERR_ELF_PARSING
;
801 goto free_symbol_table_data
;
804 /* Get the number of symbol in the table for the iteration. */
805 sym_count
= symtab_hdr
->sh_size
/ symtab_hdr
->sh_entsize
;
807 /* Loop over all symbol. */
808 for (sym_idx
= 0; sym_idx
< sym_count
; sym_idx
++) {
809 struct lttng_elf_sym curr_sym
;
811 /* Get the symbol at the current index. */
812 if (is_elf_32_bit(elf
)) {
813 Elf32_Sym tmp
= ((Elf32_Sym
*) symbol_table_data
)[sym_idx
];
814 copy_sym(tmp
, curr_sym
);
816 Elf64_Sym tmp
= ((Elf64_Sym
*) symbol_table_data
)[sym_idx
];
817 copy_sym(tmp
, curr_sym
);
821 * If the st_name field is zero, there is no string name for
822 * this symbol; skip to the next symbol.
824 if (curr_sym
.st_name
== 0) {
829 * Use the st_name field in the lttng_elf_sym struct to get offset of
830 * the symbol's name from the beginning of the string table.
832 curr_sym_str
= string_table_data
+ curr_sym
.st_name
;
835 * If the current symbol is not a function; skip to the next symbol.
837 if (ELF_ST_TYPE(curr_sym
.st_info
) != STT_FUNC
) {
842 * Compare with the search symbol. If there is a match set the address
843 * output parameter and return success.
845 if (strcmp(symbol
, curr_sym_str
) == 0 ) {
847 addr
= curr_sym
.st_value
;
853 DBG("Symbol not found.");
854 ret
= LTTNG_ERR_ELF_PARSING
;
855 goto free_string_table_data
;
859 * Use the virtual address of the symbol to compute the offset of this
860 * symbol from the beginning of the executable file.
862 ret
= lttng_elf_convert_addr_in_text_to_offset(elf
, addr
, offset
);
864 DBG("Cannot convet addr to offset.");
865 goto free_string_table_data
;
869 free_string_table_data
:
870 free(string_table_data
);
871 free_symbol_table_data
:
872 free(symbol_table_data
);
874 lttng_elf_destroy(elf
);
880 * Compute the offsets of SDT probes from the begining of the ELF binary.
882 * On success, returns 0 and the nb_probes parameter is set to the number of
883 * offsets found and the offsets parameter points to an array of offsets where
884 * the SDT probes are.
885 * On failure, returns -1.
887 int lttng_elf_get_sdt_probe_offsets(int fd
, const char *provider_name
,
888 const char *probe_name
, uint64_t **offsets
, uint32_t *nb_probes
)
890 int ret
= 0, nb_match
= 0;
891 struct lttng_elf_shdr
*stap_note_section_hdr
= NULL
;
892 struct lttng_elf
*elf
= NULL
;
893 char *stap_note_section_data
= NULL
;
894 char *curr_note_section_begin
, *curr_data_ptr
, *curr_probe
, *curr_provider
;
896 uint32_t name_size
, desc_size
, note_type
;
897 uint64_t curr_probe_location
, curr_probe_offset
, curr_semaphore_location
;
898 uint64_t *probe_locs
= NULL
, *new_probe_locs
= NULL
;
900 if (!provider_name
|| !probe_name
|| !nb_probes
|| !offsets
) {
901 DBG("Invalid arguments.");
902 ret
= LTTNG_ERR_ELF_PARSING
;
906 elf
= lttng_elf_create(fd
);
908 DBG("Error allocation ELF.");
909 ret
= LTTNG_ERR_ELF_PARSING
;
913 /* Get the stap note section header. */
914 ret
= lttng_elf_get_section_hdr_by_name(elf
, NOTE_STAPSDT_SECTION_NAME
,
915 &stap_note_section_hdr
);
917 DBG("Cannot get ELF stap note section.");
918 goto destroy_elf_error
;
921 /* Get the data associated with the stap note section. */
922 stap_note_section_data
= lttng_elf_get_section_data(elf
, stap_note_section_hdr
);
923 if (stap_note_section_data
== NULL
) {
924 DBG("Cannot get ELF stap note section data.");
925 ret
= LTTNG_ERR_ELF_PARSING
;
926 goto destroy_elf_error
;
929 next_note_ptr
= stap_note_section_data
;
930 curr_note_section_begin
= stap_note_section_data
;
934 curr_data_ptr
= next_note_ptr
;
935 /* Check if we have reached the end of the note section. */
937 curr_note_section_begin
+ stap_note_section_hdr
->sh_size
) {
938 *nb_probes
= nb_match
;
939 *offsets
= probe_locs
;
943 /* Get name size field. */
944 name_size
= next_4bytes_boundary(*(uint32_t*) curr_data_ptr
);
945 curr_data_ptr
+= sizeof(uint32_t);
947 /* Sanity check; a zero name_size is reserved. */
948 if (name_size
== 0) {
949 DBG("Invalid name size field in SDT probe descriptions"
955 /* Get description size field. */
956 desc_size
= next_4bytes_boundary(*(uint32_t*) curr_data_ptr
);
957 curr_data_ptr
+= sizeof(uint32_t);
959 /* Get type field. */
960 note_type
= *(uint32_t *) curr_data_ptr
;
961 curr_data_ptr
+= sizeof(uint32_t);
964 * Move the pointer to the next note to be ready for the next
965 * iteration. The current note is made of 3 unsigned 32bit
966 * integers (name size, descriptor size and note type), the
967 * name and the descriptor. To move to the next note, we move
968 * the pointer according to those values.
970 next_note_ptr
= next_note_ptr
+
971 (3 * sizeof(uint32_t)) + desc_size
+ name_size
;
974 * Move ptr to the end of the name string (we don't need it)
975 * and go to the next 4 byte alignement.
977 if (note_type
!= NOTE_STAPSDT_TYPE
||
978 strncmp(curr_data_ptr
, NOTE_STAPSDT_NAME
, name_size
) != 0) {
982 curr_data_ptr
+= name_size
;
984 /* Get probe location. */
985 curr_probe_location
= *(uint64_t *) curr_data_ptr
;
986 curr_data_ptr
+= sizeof(uint64_t);
988 /* Pass over the base. Not needed. */
989 curr_data_ptr
+= sizeof(uint64_t);
991 /* Get semaphore location. */
992 curr_semaphore_location
= *(uint64_t *) curr_data_ptr
;
993 curr_data_ptr
+= sizeof(uint64_t);
994 /* Get provider name. */
995 curr_provider
= curr_data_ptr
;
996 curr_data_ptr
+= strlen(curr_provider
) + 1;
998 /* Get probe name. */
999 curr_probe
= curr_data_ptr
;
1001 /* Check if the provider and probe name match */
1002 if (strcmp(provider_name
, curr_provider
) == 0 &&
1003 strcmp(probe_name
, curr_probe
) == 0) {
1007 * We currently don't support SDT probes with semaphores. Return
1008 * success as we found a matching probe but it's guarded by a
1011 if (curr_semaphore_location
!= 0) {
1012 ret
= LTTNG_ERR_SDT_PROBE_SEMAPHORE
;
1016 new_size
= (++nb_match
) * sizeof(uint64_t);
1019 * Found a match with not semaphore, we need to copy the
1020 * probe_location to the output parameter.
1022 new_probe_locs
= realloc(probe_locs
, new_size
);
1023 if (!new_probe_locs
) {
1024 /* Error allocating a larger buffer */
1025 DBG("Allocation error in SDT.");
1026 ret
= LTTNG_ERR_NOMEM
;
1029 probe_locs
= new_probe_locs
;
1030 new_probe_locs
= NULL
;
1033 * Use the virtual address of the probe to compute the offset of
1034 * this probe from the beginning of the executable file.
1036 ret
= lttng_elf_convert_addr_in_text_to_offset(elf
,
1037 curr_probe_location
, &curr_probe_offset
);
1039 DBG("Conversion error in SDT.");
1043 probe_locs
[nb_match
- 1] = curr_probe_offset
;
1048 free(stap_note_section_data
);
1050 lttng_elf_destroy(elf
);