* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#define _GNU_SOURCE
+#define _LGPL_SOURCE
#include <helper.h>
#include <string.h>
#include <lttng/align.h>
#include <lttng/ust-elf.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include "lttng-tracer-core.h"
+
+#define BUF_LEN 4096
/*
* Retrieve the nth (where n is the `index` argument) phdr (program
uint16_t index)
{
struct lttng_ust_elf_phdr *phdr = NULL;
- long offset;
+ off_t offset;
if (!elf) {
goto error;
goto error;
}
- offset = elf->ehdr->e_phoff + index * elf->ehdr->e_phentsize;
- if (fseek(elf->file, offset, SEEK_SET)) {
+ offset = (off_t) elf->ehdr->e_phoff
+ + (off_t) index * elf->ehdr->e_phentsize;
+ if (lseek(elf->fd, offset, SEEK_SET) < 0) {
goto error;
}
if (is_elf_32_bit(elf)) {
Elf32_Phdr elf_phdr;
- if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) {
+ if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr))
+ < sizeof(elf_phdr)) {
goto error;
}
if (!is_elf_native_endian(elf)) {
} else {
Elf64_Phdr elf_phdr;
- if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) {
+ if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr))
+ < sizeof(elf_phdr)) {
goto error;
}
if (!is_elf_native_endian(elf)) {
uint16_t index)
{
struct lttng_ust_elf_shdr *shdr = NULL;
- long offset;
+ off_t offset;
if (!elf) {
goto error;
goto error;
}
- offset = elf->ehdr->e_shoff + index * elf->ehdr->e_shentsize;
- if (fseek(elf->file, offset, SEEK_SET)) {
+ offset = (off_t) elf->ehdr->e_shoff
+ + (off_t) index * elf->ehdr->e_shentsize;
+ if (lseek(elf->fd, offset, SEEK_SET) < 0) {
goto error;
}
if (is_elf_32_bit(elf)) {
Elf32_Shdr elf_shdr;
- if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) {
+ if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr))
+ < sizeof(elf_shdr)) {
goto error;
}
if (!is_elf_native_endian(elf)) {
} else {
Elf64_Shdr elf_shdr;
- if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) {
+ if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr))
+ < sizeof(elf_shdr)) {
goto error;
}
if (!is_elf_native_endian(elf)) {
* If no name is found, NULL is returned.
*/
static
-char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, uint32_t offset)
+char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, off_t offset)
{
char *name = NULL;
- size_t len;
+ size_t len = 0, to_read; /* len does not include \0 */
if (!elf) {
goto error;
goto error;
}
- if (fseek(elf->file, elf->section_names_offset + offset, SEEK_SET)) {
+ if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) {
goto error;
}
- /* Note that len starts at 1, it is not an index. */
- for (len = 1; offset + len <= elf->section_names_size; ++len) {
- switch (fgetc(elf->file)) {
- case EOF:
+
+ to_read = elf->section_names_size - offset;
+
+ /* Find first \0 after or at current location, remember len. */
+ for (;;) {
+ char buf[BUF_LEN];
+ ssize_t read_len;
+ size_t i;
+
+ if (!to_read) {
goto error;
- case '\0':
- goto end;
- default:
- break;
}
+ read_len = lttng_ust_read(elf->fd, buf,
+ min_t(size_t, BUF_LEN, to_read));
+ if (read_len <= 0) {
+ goto error;
+ }
+ for (i = 0; i < read_len; i++) {
+ if (buf[i] == '\0') {
+ len += i;
+ goto end;
+ }
+ }
+ len += read_len;
+ to_read -= read_len;
}
-
- /* No name was found before the end of the table. */
- goto error;
-
end:
- name = zmalloc(sizeof(char) * len);
+ name = zmalloc(sizeof(char) * (len + 1)); /* + 1 for \0 */
if (!name) {
goto error;
}
- if (fseek(elf->file, elf->section_names_offset + offset,
- SEEK_SET)) {
+ if (lseek(elf->fd, elf->section_names_offset + offset,
+ SEEK_SET) < 0) {
goto error;
}
- if (!fgets(name, len, elf->file)) {
+ if (lttng_ust_read(elf->fd, name, len + 1) < len + 1) {
goto error;
}
{
uint8_t e_ident[EI_NIDENT];
struct lttng_ust_elf_shdr *section_names_shdr;
- struct lttng_ust_elf *elf;
+ struct lttng_ust_elf *elf = NULL;
elf = zmalloc(sizeof(struct lttng_ust_elf));
if (!elf) {
goto error;
}
- elf->file = fopen(elf->path, "rb");
- if (!elf->file) {
+ elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC);
+ if (elf->fd < 0) {
goto error;
}
- if (!fread(e_ident, 1, EI_NIDENT, elf->file)) {
+ if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) {
goto error;
}
elf->bitness = e_ident[EI_CLASS];
elf->endianness = e_ident[EI_DATA];
- rewind(elf->file);
+
+ if (lseek(elf->fd, 0, SEEK_SET) < 0) {
+ goto error;
+ }
elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr));
if (!elf->ehdr) {
if (is_elf_32_bit(elf)) {
Elf32_Ehdr elf_ehdr;
- if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) {
+ if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr))
+ < sizeof(elf_ehdr)) {
goto error;
}
if (!is_elf_native_endian(elf)) {
} else {
Elf64_Ehdr elf_ehdr;
- if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) {
+ if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr))
+ < sizeof(elf_ehdr)) {
goto error;
}
if (!is_elf_native_endian(elf)) {
elf->section_names_size = section_names_shdr->sh_size;
free(section_names_shdr);
-
return elf;
error:
if (elf) {
free(elf->ehdr);
- fclose(elf->file);
+ if (elf->fd >= 0) {
+ if (close(elf->fd)) {
+ abort();
+ }
+ }
free(elf->path);
+ free(elf);
}
- free(elf);
return NULL;
}
+/*
+ * Test whether the ELF file is position independent code (PIC)
+ */
+uint8_t lttng_ust_elf_is_pic(struct lttng_ust_elf *elf)
+{
+ /*
+ * PIC has and e_type value of ET_DYN, see ELF specification
+ * version 1.1 p. 1-3.
+ */
+ return elf->ehdr->e_type == ET_DYN;
+}
+
/*
* Destroy the given lttng_ust_elf instance.
*/
}
free(elf->ehdr);
- fclose(elf->file);
+ if (close(elf->fd)) {
+ abort();
+ }
free(elf->path);
free(elf);
}
int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz)
{
uint16_t i;
- uint64_t _memsz = 0;
+ uint64_t low_addr = UINT64_MAX, high_addr = 0;
if (!elf || !memsz) {
goto error;
for (i = 0; i < elf->ehdr->e_phnum; ++i) {
struct lttng_ust_elf_phdr *phdr;
- uint64_t align;
phdr = lttng_ust_elf_get_phdr(elf, i);
if (!phdr) {
goto next_loop;
}
- /*
- * A p_align of 0 means no alignment, i.e. aligned to
- * 1 byte.
- */
- align = phdr->p_align == 0 ? 1 : phdr->p_align;
- /* Align the start of the segment. */
- _memsz += offset_align(_memsz, align);
- _memsz += phdr->p_memsz;
- /*
- * Add padding at the end of the segment, so it ends
- * on a multiple of the align value (which usually
- * means a page boundary). This makes the computation
- * valid even in cases where p_align would change from
- * one segment to the next.
- */
- _memsz += offset_align(_memsz, align);
+ low_addr = min_t(uint64_t, low_addr, phdr->p_vaddr);
+ high_addr = max_t(uint64_t, high_addr,
+ phdr->p_vaddr + phdr->p_memsz);
next_loop:
free(phdr);
}
- *memsz = _memsz;
+ if (high_addr < low_addr) {
+ /* No PT_LOAD segments or corrupted data. */
+ goto error;
+ }
+
+ *memsz = high_addr - low_addr;
return 0;
error:
return -1;
static
int lttng_ust_elf_get_build_id_from_segment(
struct lttng_ust_elf *elf, uint8_t **build_id, size_t *length,
- uint64_t offset, uint64_t segment_end, int *found)
+ off_t offset, off_t segment_end)
{
- uint8_t *_build_id;
- size_t _length;
- int _found = 0;
+ uint8_t *_build_id = NULL; /* Silence old gcc warning. */
+ size_t _length = 0; /* Silence old gcc warning. */
while (offset < segment_end) {
struct lttng_ust_elf_nhdr nhdr;
+ size_t read_len;
/* Align start of note entry */
offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN);
* build id the data following the header will not
* have been read.
*/
- if (fseek(elf->file, offset, SEEK_SET)) {
+ if (lseek(elf->fd, offset, SEEK_SET) < 0) {
goto error;
}
- if (!fread(&nhdr, sizeof(nhdr), 1, elf->file)) {
+ if (lttng_ust_read(elf->fd, &nhdr, sizeof(nhdr))
+ < sizeof(nhdr)) {
goto error;
}
_length = nhdr.n_descsz;
_build_id = zmalloc(sizeof(uint8_t) * _length);
- if (!build_id) {
+ if (!_build_id) {
goto error;
}
- if (fseek(elf->file, offset, SEEK_SET)) {
+ if (lseek(elf->fd, offset, SEEK_SET) < 0) {
goto error;
}
- if (!fread(_build_id, sizeof(*_build_id), _length, elf->file)) {
+ read_len = sizeof(*_build_id) * _length;
+ if (lttng_ust_read(elf->fd, _build_id, read_len) < read_len) {
goto error;
}
- _found = 1;
break;
}
- if (_found) {
+ if (_build_id) {
*build_id = _build_id;
*length = _length;
}
- *found = _found;
return 0;
error:
+ free(_build_id);
return -1;
}
size_t *length, int *found)
{
uint16_t i;
- uint8_t *_build_id;
- size_t _length;
- int _found = 0;
+ uint8_t *_build_id = NULL; /* Silence old gcc warning. */
+ size_t _length = 0; /* Silence old gcc warning. */
if (!elf || !build_id || !length || !found) {
goto error;
}
for (i = 0; i < elf->ehdr->e_phnum; ++i) {
- uint64_t offset, segment_end;
+ off_t offset, segment_end;
struct lttng_ust_elf_phdr *phdr;
- int ret;
+ int ret = 0;
phdr = lttng_ust_elf_get_phdr(elf, i);
if (!phdr) {
offset = phdr->p_offset;
segment_end = offset + phdr->p_filesz;
ret = lttng_ust_elf_get_build_id_from_segment(
- elf, &_build_id, &_length, offset, segment_end,
- &_found);
+ elf, &_build_id, &_length, offset, segment_end);
next_loop:
free(phdr);
if (ret) {
goto error;
}
- if (_found) {
+ if (_build_id) {
break;
}
}
- if (_found) {
+ if (_build_id) {
*build_id = _build_id;
*length = _length;
+ *found = 1;
+ } else {
+ *found = 0;
}
- *found = _found;
return 0;
error:
+ free(_build_id);
return -1;
}
*
* Returns 0 on success, -1 if an error occurred.
*/
-static
int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf,
char **filename, uint32_t *crc,
- int *found,
struct lttng_ust_elf_shdr *shdr)
{
- int _found = 0;
- char *_filename;
+ char *_filename = NULL; /* Silence old gcc warning. */
+ size_t filename_len;
char *section_name = NULL;
- uint32_t _crc;
+ uint32_t _crc = 0; /* Silence old gcc warning. */
- if (!elf || !filename || !crc || !found || !shdr) {
+ if (!elf || !filename || !crc || !shdr) {
goto error;
}
if (!_filename) {
goto error;
}
- if (fseek(elf->file, shdr->sh_offset, SEEK_SET)) {
+ if (lseek(elf->fd, shdr->sh_offset, SEEK_SET) < 0) {
goto error;
}
- if (!fread(_filename, sizeof(*_filename), shdr->sh_size - ELF_CRC_SIZE,
- elf->file)) {
+ filename_len = sizeof(*_filename) * (shdr->sh_size - ELF_CRC_SIZE);
+ if (lttng_ust_read(elf->fd, _filename, filename_len) < filename_len) {
goto error;
}
- if (!fread(&_crc, sizeof(_crc), 1, elf->file)) {
+ if (lttng_ust_read(elf->fd, &_crc, sizeof(_crc)) < sizeof(_crc)) {
goto error;
}
if (!is_elf_native_endian(elf)) {
_crc = bswap_32(_crc);
}
- _found = 1;
-
end:
free(section_name);
- if (_found) {
+ if (_filename) {
*filename = _filename;
*crc = _crc;
}
- *found = _found;
return 0;
error:
- if (section_name) {
- free(section_name);
- }
-
+ free(_filename);
+ free(section_name);
return -1;
}
{
int ret;
uint16_t i;
- int _found = 0;
- char *_filename;
- uint32_t _crc;
+ char *_filename = NULL; /* Silence old gcc warning. */
+ uint32_t _crc = 0; /* Silence old gcc warning. */
if (!elf || !filename || !crc || !found) {
goto error;
}
ret = lttng_ust_elf_get_debug_link_from_section(
- elf, &_filename, &_crc, &_found, shdr);
+ elf, &_filename, &_crc, shdr);
free(shdr);
if (ret) {
goto error;
}
- if (_found) {
+ if (_filename) {
break;
}
}
- if (_found) {
+ if (_filename) {
*filename = _filename;
*crc = _crc;
+ *found = 1;
+ } else {
+ *found = 0;
}
- *found = _found;
return 0;
+
error:
+ free(_filename);
return -1;
}