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drgn/libdrgn/dwarf_index.c
Omar Sandoval a17215e984 libdrgn: dwarf_index: fix memcpy() undefined behavior 
Apparently, it's undefined behavior to pass NULL as the source to
memcpy(), even if the length is zero. It's an easy fix, so let's appease
UBSan.
2019-07-15 12:27:48 -07:00

1777 lines
43 KiB
C
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// Copyright 2018-2019 - Omar Sandoval
// SPDX-License-Identifier: GPL-3.0+
#include <assert.h>
#include <dwarf.h>
#include <elfutils/libdw.h>
#include <fcntl.h>
#include <gelf.h>
#include <inttypes.h>
#include <libelf.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "internal.h"
#include "elf_relocator.h"
#include "dwarf_index.h"
#include "read.h"
#include "siphash.h"
#include "string_builder.h"
#include "vector.h"
struct drgn_dwfl_module_userdata *drgn_dwfl_module_userdata_create(void)
{
struct drgn_dwfl_module_userdata *userdata;
userdata = calloc(1, sizeof(*userdata));
if (userdata)
userdata->fd = -1;
return userdata;
}
void
drgn_dwfl_module_userdata_destroy(struct drgn_dwfl_module_userdata *userdata)
{
if (userdata) {
elf_end(userdata->elf);
if (userdata->fd != -1)
close(userdata->fd);
free(userdata->path);
free(userdata);
}
}
void
drgn_dwfl_module_userdata_set_error(struct drgn_dwfl_module_userdata *userdata,
const char *message, struct drgn_error *err)
{
if (userdata->err)
drgn_error_destroy(userdata->err);
if (message && err) {
struct string_builder sb = {};
if (!string_builder_appendf(&sb, "%s: ", message) ||
!string_builder_append_error(&sb, err)) {
drgn_error_destroy(err);
free(sb.str);
userdata->err = &drgn_enomem;
return;
}
drgn_error_destroy(err);
userdata->err = drgn_error_from_string_builder(DRGN_ERROR_MISSING_DEBUG_INFO,
&sb);
} else if (message) {
userdata->err = drgn_error_create(DRGN_ERROR_MISSING_DEBUG_INFO,
message);
} else {
userdata->err = err;
}
}
/**
* @c Dwfl_Callbacks::find_elf() implementation.
*
* Ideally we'd use @c dwfl_report_elf() instead, but that doesn't work for a
* couple of reasons:
*
* - vmlinux is usually an @c ET_EXEC ELF file, but when KASLR is enabled, it
* needs to be handled like an @c ET_DYN file. libdwfl has a hack for this
* when @c dwfl_report_module() is used, but @ref dwfl_report_elf() doesn't
* support this hack.
* - For kernel modules, we want to set the section addresses in the @c Elf
* handle ourselves instead of using @c Dwfl_Callbacks::section_address(), but
* @c dwfl_report_elf() doesn't take an @c Elf handle.
*
* So, we're stuck with using @c dwfl_report_module() and this dummy callback.
*/
static int drgn_dwfl_find_elf(Dwfl_Module *module, void **userdatap,
const char *name, Dwarf_Addr base,
char **file_name, Elf **elfp)
{
struct drgn_dwfl_module_userdata *userdata = *userdatap;
int fd;
if (userdata->err) {
*file_name = NULL;
*elfp = NULL;
return -1;
}
/*
* libdwfl consumes the returned path, file descriptor, and ELF handle,
* so clear the fields.
*/
*file_name = userdata->path;
fd = userdata->fd;
*elfp = userdata->elf;
userdata->path = NULL;
userdata->fd = -1;
userdata->elf = NULL;
return fd;
}
/**
* @c Dwfl_Callbacks::section_address() implementation.
*
* We set the section header @c sh_addr in memory instead of using this, but
* libdwfl requires the callback pointer to be non-@c NULL. It will be called
* for any sections that still have a zero @c sh_addr, meaning they are not
* present in memory.
*/
static int drgn_dwfl_section_address(Dwfl_Module *module, void **userdatap,
const char *name, Dwarf_Addr base,
const char *secname, Elf32_Word shndx,
const GElf_Shdr *shdr, Dwarf_Addr *addr)
{
*addr = -1;
return DWARF_CB_OK;
}
const Dwfl_Callbacks drgn_dwfl_callbacks = {
.find_elf = drgn_dwfl_find_elf,
.find_debuginfo = dwfl_standard_find_debuginfo,
.section_address = drgn_dwfl_section_address,
};
enum {
SECTION_DEBUG_ABBREV,
SECTION_DEBUG_INFO,
SECTION_DEBUG_LINE,
SECTION_DEBUG_STR,
DRGN_DWARF_INDEX_NUM_SECTIONS,
};
static const char * const section_name[DRGN_DWARF_INDEX_NUM_SECTIONS] = {
[SECTION_DEBUG_ABBREV] = ".debug_abbrev",
[SECTION_DEBUG_INFO] = ".debug_info",
[SECTION_DEBUG_LINE] = ".debug_line",
[SECTION_DEBUG_STR] = ".debug_str",
};
/*
* The DWARF abbreviation table gets translated into a series of instructions.
* An instruction <= INSN_MAX_SKIP indicates a number of bytes to be skipped
* over. The next few instructions mean that the corresponding attribute can be
* skipped over. The remaining instructions indicate that the corresponding
* attribute should be parsed. Finally, every sequence of instructions
* corresponding to a DIE is terminated by a zero byte followed by a bitmask of
* TAG_FLAG_* bits combined with the DWARF tag (which may be set to zero if the
* tag is not of interest).
*/
enum {
INSN_MAX_SKIP = 229,
ATTRIB_BLOCK1,
ATTRIB_BLOCK2,
ATTRIB_BLOCK4,
ATTRIB_EXPRLOC,
ATTRIB_LEB128,
ATTRIB_STRING,
ATTRIB_SIBLING_REF1,
ATTRIB_SIBLING_REF2,
ATTRIB_SIBLING_REF4,
ATTRIB_SIBLING_REF8,
ATTRIB_SIBLING_REF_UDATA,
ATTRIB_NAME_STRP4,
ATTRIB_NAME_STRP8,
ATTRIB_NAME_STRING,
ATTRIB_STMT_LIST_LINEPTR4,
ATTRIB_STMT_LIST_LINEPTR8,
ATTRIB_DECL_FILE_DATA1,
ATTRIB_DECL_FILE_DATA2,
ATTRIB_DECL_FILE_DATA4,
ATTRIB_DECL_FILE_DATA8,
ATTRIB_DECL_FILE_UDATA,
ATTRIB_SPECIFICATION_REF1,
ATTRIB_SPECIFICATION_REF2,
ATTRIB_SPECIFICATION_REF4,
ATTRIB_SPECIFICATION_REF8,
ATTRIB_SPECIFICATION_REF_UDATA,
ATTRIB_MAX_INSN = ATTRIB_SPECIFICATION_REF_UDATA,
};
enum {
/* Maximum number of bits used by the tags we care about. */
TAG_BITS = 6,
TAG_MASK = (1 << TAG_BITS) - 1,
/* The remaining bits can be used for other purposes. */
TAG_FLAG_DECLARATION = 0x40,
TAG_FLAG_CHILDREN = 0x80,
};
DEFINE_VECTOR(uint8_vector, uint8_t)
DEFINE_VECTOR(uint32_vector, uint32_t)
DEFINE_VECTOR(uint64_vector, uint64_t)
struct abbrev_table {
/*
* This is indexed on the DWARF abbreviation code minus one. It maps the
* abbreviation code to an index in insns where the instruction stream
* for that code begins.
*
* Technically, abbreviation codes don't have to be sequential. In
* practice, GCC seems to always generate sequential codes starting at
* one, so we can get away with a flat array.
*/
struct uint32_vector decls;
struct uint8_vector insns;
};
static void abbrev_table_init(struct abbrev_table *abbrev)
{
uint32_vector_init(&abbrev->decls);
uint8_vector_init(&abbrev->insns);
}
static void abbrev_table_deinit(struct abbrev_table *abbrev)
{
uint8_vector_deinit(&abbrev->insns);
uint32_vector_deinit(&abbrev->decls);
}
struct compilation_unit {
Dwfl_Module *module;
Elf_Data *sections[DRGN_DWARF_INDEX_NUM_SECTIONS];
const char *ptr;
uint64_t unit_length;
uint64_t debug_abbrev_offset;
uint8_t address_size;
bool is_64_bit;
bool bswap;
};
static inline const char *section_ptr(Elf_Data *data, size_t offset)
{
return &((char *)data->d_buf)[offset];
}
static inline const char *section_end(Elf_Data *data)
{
return section_ptr(data, data->d_size);
}
/*
* An indexed DIE.
*
* DIEs with the same name but different tags or files are considered distinct.
* We only compare the hash of the file name, not the string value, because a
* 64-bit collision is unlikely enough, especially when also considering the
* name and tag.
*/
struct drgn_dwarf_index_die {
uint64_t tag;
uint64_t file_name_hash;
/*
* The next DIE with the same name (as an index into
* drgn_dwarf_index_shard::dies), or SIZE_MAX if this is the last DIE.
*/
size_t next;
Dwfl_Module *module;
uint64_t offset;
};
/*
* The key is the DIE name. The value is the first DIE with that name (as an
* index into drgn_dwarf_index_shard::dies).
*/
DEFINE_HASH_TABLE_FUNCTIONS(drgn_dwarf_index_die_map, string_hash, string_eq)
DEFINE_VECTOR_FUNCTIONS(drgn_dwarf_index_die_vector)
static inline size_t hash_pair_to_shard(struct hash_pair hp)
{
/*
* The 8 most significant bits of the hash are used as the F14 tag, so
* we don't want to use those for sharding.
*/
return ((hp.first >>
(8 * sizeof(size_t) - 8 - DRGN_DWARF_INDEX_SHARD_BITS)) &
(((size_t)1 << DRGN_DWARF_INDEX_SHARD_BITS) - 1));
}
static inline struct drgn_error *drgn_eof(void)
{
return drgn_error_create(DRGN_ERROR_DWARF_FORMAT,
"debug information is truncated");
}
static inline bool skip_leb128(const char **ptr, const char *end)
{
for (;;) {
if (*ptr >= end)
return false;
if (!(*(const uint8_t *)(*ptr)++ & 0x80))
return true;
}
}
static inline struct drgn_error *read_uleb128(const char **ptr, const char *end,
uint64_t *value)
{
int shift = 0;
uint8_t byte;
*value = 0;
for (;;) {
if (*ptr >= end)
return drgn_eof();
byte = *(const uint8_t *)*ptr;
(*ptr)++;
if (shift == 63 && byte > 1) {
return drgn_error_create(DRGN_ERROR_OVERFLOW,
"ULEB128 overflowed unsigned 64-bit integer");
}
*value |= (uint64_t)(byte & 0x7f) << shift;
shift += 7;
if (!(byte & 0x80))
break;
}
return NULL;
}
static inline struct drgn_error *read_uleb128_into_size_t(const char **ptr,
const char *end,
size_t *value)
{
struct drgn_error *err;
uint64_t tmp;
if ((err = read_uleb128(ptr, end, &tmp)))
return err;
if (tmp > SIZE_MAX)
return drgn_eof();
*value = tmp;
return NULL;
}
static void free_shards(struct drgn_dwarf_index *dindex, size_t n)
{
size_t i;
for (i = 0; i < n; i++) {
drgn_dwarf_index_die_vector_deinit(&dindex->shards[i].dies);
drgn_dwarf_index_die_map_deinit(&dindex->shards[i].map);
omp_destroy_lock(&dindex->shards[i].lock);
}
}
void drgn_dwarf_index_init(struct drgn_dwarf_index *dindex)
{
size_t i;
for (i = 0; i < ARRAY_SIZE(dindex->shards); i++) {
struct drgn_dwarf_index_shard *shard = &dindex->shards[i];
omp_init_lock(&shard->lock);
drgn_dwarf_index_die_map_init(&shard->map);
drgn_dwarf_index_die_vector_init(&shard->dies);
}
}
void drgn_dwarf_index_deinit(struct drgn_dwarf_index *dindex)
{
if (dindex)
free_shards(dindex, ARRAY_SIZE(dindex->shards));
}
static struct drgn_error *get_debug_sections(Elf *elf, Elf_Data **sections)
{
struct drgn_error *err;
size_t shstrndx;
Elf_Scn *scn = NULL;
size_t i;
Elf_Data *debug_str;
if (elf_getshdrstrndx(elf, &shstrndx))
return drgn_error_libelf();
while ((scn = elf_nextscn(elf, scn))) {
GElf_Shdr *shdr, shdr_mem;
const char *scnname;
shdr = gelf_getshdr(scn, &shdr_mem);
if (!shdr)
return drgn_error_libelf();
if (shdr->sh_type == SHT_NOBITS || (shdr->sh_flags & SHF_GROUP))
continue;
scnname = elf_strptr(elf, shstrndx, shdr->sh_name);
if (!scnname)
continue;
for (i = 0; i < DRGN_DWARF_INDEX_NUM_SECTIONS; i++) {
if (sections[i])
continue;
if (strcmp(scnname, section_name[i]) != 0)
continue;
err = read_elf_section(scn, &sections[i]);
if (err)
return err;
}
}
for (i = 0; i < DRGN_DWARF_INDEX_NUM_SECTIONS; i++) {
if (i != SECTION_DEBUG_LINE && !sections[i]) {
return drgn_error_format(DRGN_ERROR_MISSING_DEBUG_INFO,
"ELF file has no %s section",
section_name[i]);
}
}
debug_str = sections[SECTION_DEBUG_STR];
if (debug_str->d_size == 0 ||
((char *)debug_str->d_buf)[debug_str->d_size - 1] != '\0') {
return drgn_error_create(DRGN_ERROR_DWARF_FORMAT,
".debug_str is not null terminated");
}
return NULL;
}
static struct drgn_error *apply_relocations(Dwfl_Module **modules,
size_t num_modules)
{
struct drgn_error *err;
struct drgn_elf_relocator relocator;
size_t i;
drgn_elf_relocator_init(&relocator);
for (i = 0; i < num_modules; i++) {
void **userdatap;
struct drgn_dwfl_module_userdata *userdata;
dwfl_module_info(modules[i], &userdatap, NULL, NULL, NULL, NULL,
NULL, NULL);
userdata = *userdatap;
if (userdata->elf) {
err = drgn_elf_relocator_add_elf(&relocator,
userdata->elf);
if (err)
goto out;
}
}
err = drgn_elf_relocator_apply(&relocator);
out:
drgn_elf_relocator_deinit(&relocator);
return err;
}
static struct drgn_error *read_compilation_unit_header(const char *ptr,
const char *end,
struct compilation_unit *cu)
{
uint32_t tmp;
uint16_t version;
if (!read_u32(&ptr, end, cu->bswap, &tmp))
return drgn_eof();
cu->is_64_bit = tmp == UINT32_C(0xffffffff);
if (cu->is_64_bit) {
if (!read_u64(&ptr, end, cu->bswap, &cu->unit_length))
return drgn_eof();
} else {
cu->unit_length = tmp;
}
if (!read_u16(&ptr, end, cu->bswap, &version))
return drgn_eof();
if (version != 2 && version != 3 && version != 4) {
return drgn_error_format(DRGN_ERROR_DWARF_FORMAT,
"unknown DWARF CU version %" PRIu16,
version);
}
if (cu->is_64_bit) {
if (!read_u64(&ptr, end, cu->bswap, &cu->debug_abbrev_offset))
return drgn_eof();
} else {
if (!read_u32_into_u64(&ptr, end, cu->bswap,
&cu->debug_abbrev_offset))
return drgn_eof();
}
if (!read_u8(&ptr, end, &cu->address_size))
return drgn_eof();
return NULL;
}
DEFINE_VECTOR(compilation_unit_vector, struct compilation_unit)
static struct drgn_error *read_cus(struct drgn_dwarf_index *dindex,
Dwfl_Module **modules, size_t num_modules,
struct compilation_unit_vector *all_cus)
{
struct drgn_error *err = NULL;
#pragma omp parallel
{
struct compilation_unit_vector cus;
size_t i;
compilation_unit_vector_init(&cus);
#pragma omp for schedule(dynamic)
for (i = 0; i < num_modules; i++) {
struct drgn_error *err2;
struct drgn_dwfl_module_userdata *userdata;
Dwarf *dwarf;
Dwarf_Addr bias;
Elf *elf;
bool bswap;
Elf_Data *sections[DRGN_DWARF_INDEX_NUM_SECTIONS] = {};
const char *ptr, *end;
if (err)
continue;
userdata = drgn_dwfl_module_userdata(modules[i]);
if (userdata->err)
continue;
/*
* Note: not dwfl_module_getelf(), because then libdwfl
* applies ELF relocations to all sections, not just
* debug sections.
*/
dwarf = dwfl_module_getdwarf(modules[i], &bias);
if (!dwarf) {
drgn_dwfl_module_userdata_set_error(userdata,
NULL,
drgn_error_libdwfl());
continue;
}
elf = dwarf_getelf(dwarf);
if (!elf) {
drgn_dwfl_module_userdata_set_error(userdata,
NULL,
drgn_error_libdw());
continue;
}
bswap = (elf_getident(elf, NULL)[EI_DATA] !=
(__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ?
ELFDATA2LSB : ELFDATA2MSB));
err2 = get_debug_sections(elf, sections);
if (err2) {
#pragma omp critical(drgn_read_cus)
{
if (err)
drgn_error_destroy(err2);
else
err = err2;
}
continue;
}
ptr = section_ptr(sections[SECTION_DEBUG_INFO], 0);
end = section_end(sections[SECTION_DEBUG_INFO]);
while (ptr < end) {
struct compilation_unit *cu;
cu = compilation_unit_vector_append_entry(&cus);
if (!cu) {
#pragma omp critical(drgn_read_cus)
{
if (!err)
err = &drgn_enomem;
}
break;
}
cu->module = modules[i];
memcpy(cu->sections, sections, sizeof(cu->sections));
cu->ptr = ptr;
cu->bswap = bswap;
err2 = read_compilation_unit_header(ptr, end, cu);
if (err2) {
#pragma omp critical(drgn_read_cus)
{
if (err)
drgn_error_destroy(err2);
else
err = err2;
}
break;
}
ptr += (cu->is_64_bit ? 12 : 4) + cu->unit_length;
}
}
if (cus.size) {
#pragma omp critical(drgn_read_cus)
if (!err) {
if (compilation_unit_vector_reserve(all_cus,
all_cus->size + cus.size)) {
memcpy(all_cus->data + all_cus->size,
cus.data,
cus.size * sizeof(*cus.data));
all_cus->size += cus.size;
} else {
err = &drgn_enomem;
}
}
}
compilation_unit_vector_deinit(&cus);
}
return err;
}
static struct drgn_error *read_abbrev_decl(const char **ptr, const char *end,
const struct compilation_unit *cu,
struct abbrev_table *abbrev)
{
struct drgn_error *err;
uint64_t code;
uint32_t insn_index;
uint64_t tag;
uint8_t children;
uint8_t die_flags;
bool should_index;
bool first = true;
uint8_t insn;
static_assert(ATTRIB_MAX_INSN == UINT8_MAX,
"maximum DWARF attribute instruction is invalid");
if ((err = read_uleb128(ptr, end, &code)))
return err;
if (code == 0)
return &drgn_stop;
if (code != abbrev->decls.size + 1) {
return drgn_error_create(DRGN_ERROR_DWARF_FORMAT,
"DWARF abbreviation table is not sequential");
}
insn_index = abbrev->insns.size;
if (!uint32_vector_append(&abbrev->decls, &insn_index))
return &drgn_enomem;
if ((err = read_uleb128(ptr, end, &tag)))
return err;
switch (tag) {
/* Types. */
case DW_TAG_base_type:
case DW_TAG_class_type:
case DW_TAG_enumeration_type:
case DW_TAG_structure_type:
case DW_TAG_typedef:
case DW_TAG_union_type:
/* Variables. */
case DW_TAG_variable:
/* Constants. */
case DW_TAG_enumerator:
/* Functions. */
case DW_TAG_subprogram:
should_index = true;
break;
default:
should_index = false;
break;
}
if (should_index || tag == DW_TAG_compile_unit)
die_flags = tag;
else
die_flags = 0;
if (!read_u8(ptr, end, &children))
return drgn_eof();
if (children)
die_flags |= TAG_FLAG_CHILDREN;
for (;;) {
uint64_t name, form;
if ((err = read_uleb128(ptr, end, &name)))
return err;
if ((err = read_uleb128(ptr, end, &form)))
return err;
if (name == 0 && form == 0)
break;
if (name == DW_AT_sibling && tag != DW_TAG_enumeration_type) {
/*
* If we are indexing enumerators, we must descend into
* DW_TAG_enumeration_type to find the DW_TAG_enumerator
* children instead of skipping to the sibling DIE.
*/
switch (form) {
case DW_FORM_ref1:
insn = ATTRIB_SIBLING_REF1;
goto append_insn;
case DW_FORM_ref2:
insn = ATTRIB_SIBLING_REF2;
goto append_insn;
case DW_FORM_ref4:
insn = ATTRIB_SIBLING_REF4;
goto append_insn;
case DW_FORM_ref8:
insn = ATTRIB_SIBLING_REF8;
goto append_insn;
case DW_FORM_ref_udata:
insn = ATTRIB_SIBLING_REF_UDATA;
goto append_insn;
default:
break;
}
} else if (name == DW_AT_name && should_index) {
switch (form) {
case DW_FORM_strp:
if (cu->is_64_bit)
insn = ATTRIB_NAME_STRP8;
else
insn = ATTRIB_NAME_STRP4;
goto append_insn;
case DW_FORM_string:
insn = ATTRIB_NAME_STRING;
goto append_insn;
default:
break;
}
} else if (name == DW_AT_stmt_list &&
tag == DW_TAG_compile_unit &&
cu->sections[SECTION_DEBUG_LINE]) {
switch (form) {
case DW_FORM_data4:
insn = ATTRIB_STMT_LIST_LINEPTR4;
goto append_insn;
case DW_FORM_data8:
insn = ATTRIB_STMT_LIST_LINEPTR8;
goto append_insn;
case DW_FORM_sec_offset:
if (cu->is_64_bit)
insn = ATTRIB_STMT_LIST_LINEPTR8;
else
insn = ATTRIB_STMT_LIST_LINEPTR4;
goto append_insn;
default:
break;
}
} else if (name == DW_AT_decl_file && should_index) {
switch (form) {
case DW_FORM_data1:
insn = ATTRIB_DECL_FILE_DATA1;
goto append_insn;
case DW_FORM_data2:
insn = ATTRIB_DECL_FILE_DATA2;
goto append_insn;
case DW_FORM_data4:
insn = ATTRIB_DECL_FILE_DATA4;
goto append_insn;
case DW_FORM_data8:
insn = ATTRIB_DECL_FILE_DATA8;
goto append_insn;
/*
* decl_file must be positive, so if the compiler uses
* DW_FORM_sdata for some reason, just treat it as
* udata.
*/
case DW_FORM_sdata:
case DW_FORM_udata:
insn = ATTRIB_DECL_FILE_UDATA;
goto append_insn;
default:
break;
}
} else if (name == DW_AT_declaration) {
/*
* In theory, this could be DW_FORM_flag with a value of
* zero, but in practice, GCC always uses
* DW_FORM_flag_present.
*/
die_flags |= TAG_FLAG_DECLARATION;
} else if (name == DW_AT_specification && should_index) {
switch (form) {
case DW_FORM_ref1:
insn = ATTRIB_SPECIFICATION_REF1;
goto append_insn;
case DW_FORM_ref2:
insn = ATTRIB_SPECIFICATION_REF2;
goto append_insn;
case DW_FORM_ref4:
insn = ATTRIB_SPECIFICATION_REF4;
goto append_insn;
case DW_FORM_ref8:
insn = ATTRIB_SPECIFICATION_REF8;
goto append_insn;
case DW_FORM_ref_udata:
insn = ATTRIB_SPECIFICATION_REF_UDATA;
goto append_insn;
default:
break;
}
}
switch (form) {
case DW_FORM_addr:
insn = cu->address_size;
break;
case DW_FORM_data1:
case DW_FORM_ref1:
case DW_FORM_flag:
insn = 1;
break;
case DW_FORM_data2:
case DW_FORM_ref2:
insn = 2;
break;
case DW_FORM_data4:
case DW_FORM_ref4:
insn = 4;
break;
case DW_FORM_data8:
case DW_FORM_ref8:
case DW_FORM_ref_sig8:
insn = 8;
break;
case DW_FORM_block1:
insn = ATTRIB_BLOCK1;
goto append_insn;
case DW_FORM_block2:
insn = ATTRIB_BLOCK2;
goto append_insn;
case DW_FORM_block4:
insn = ATTRIB_BLOCK4;
goto append_insn;
case DW_FORM_exprloc:
insn = ATTRIB_EXPRLOC;
goto append_insn;
case DW_FORM_sdata:
case DW_FORM_udata:
case DW_FORM_ref_udata:
insn = ATTRIB_LEB128;
goto append_insn;
case DW_FORM_ref_addr:
case DW_FORM_sec_offset:
case DW_FORM_strp:
insn = cu->is_64_bit ? 8 : 4;
break;
case DW_FORM_string:
insn = ATTRIB_STRING;
goto append_insn;
case DW_FORM_flag_present:
continue;
case DW_FORM_indirect:
return drgn_error_create(DRGN_ERROR_DWARF_FORMAT,
"DW_FORM_indirect is not implemented");
default:
return drgn_error_format(DRGN_ERROR_DWARF_FORMAT,
"unknown attribute form %" PRIu64,
form);
}
if (!first) {
uint8_t last_insn;
last_insn = abbrev->insns.data[abbrev->insns.size - 1];
if (last_insn + insn <= INSN_MAX_SKIP) {
abbrev->insns.data[abbrev->insns.size - 1] += insn;
continue;
} else if (last_insn < INSN_MAX_SKIP) {
insn = last_insn + insn - INSN_MAX_SKIP;
abbrev->insns.data[abbrev->insns.size - 1] =
INSN_MAX_SKIP;
}
}
append_insn:
first = false;
if (!uint8_vector_append(&abbrev->insns, &insn))
return &drgn_enomem;
}
insn = 0;
if (!uint8_vector_append(&abbrev->insns, &insn) ||
!uint8_vector_append(&abbrev->insns, &die_flags))
return &drgn_enomem;
return NULL;
}
static struct drgn_error *read_abbrev_table(const char *ptr, const char *end,
const struct compilation_unit *cu,
struct abbrev_table *abbrev)
{
struct drgn_error *err;
for (;;) {
err = read_abbrev_decl(&ptr, end, cu, abbrev);
if (err && err->code == DRGN_ERROR_STOP)
break;
else if (err)
return err;
}
return NULL;
}
static struct drgn_error *skip_lnp_header(struct compilation_unit *cu,
const char **ptr, const char *end)
{
uint32_t tmp;
bool is_64_bit;
uint16_t version;
uint8_t opcode_base;
if (!read_u32(ptr, end, cu->bswap, &tmp))
return drgn_eof();
is_64_bit = tmp == UINT32_C(0xffffffff);
if (is_64_bit)
*ptr += sizeof(uint64_t);
if (!read_u16(ptr, end, cu->bswap, &version))
return drgn_eof();
if (version != 2 && version != 3 && version != 4) {
return drgn_error_format(DRGN_ERROR_DWARF_FORMAT,
"unknown DWARF LNP version %" PRIu16,
version);
}
/*
* header_length
* minimum_instruction_length
* maximum_operations_per_instruction (DWARF 4 only)
* default_is_stmt
* line_base
* line_range
*/
*ptr += (is_64_bit ? 8 : 4) + 4 + (version >= 4);
if (!read_u8(ptr, end, &opcode_base))
return drgn_eof();
/* standard_opcode_lengths */
*ptr += opcode_base - 1;
return NULL;
}
/*
* Hash the canonical path of a directory. Components are hashed in reverse
* order. We always include a trailing slash.
*/
static void hash_directory(struct siphash *hash, const char *path,
size_t path_len)
{
struct path_iterator it = {
.components = (struct path_iterator_component []){
{ path, path_len, },
},
.num_components = 1,
};
const char *component;
size_t component_len;
while (path_iterator_next(&it, &component, &component_len)) {
siphash_update(hash, component, component_len);
siphash_update(hash, "/", 1);
}
}
DEFINE_VECTOR(siphash_vector, struct siphash)
static struct drgn_error *
read_file_name_table(struct drgn_dwarf_index *dindex,
struct compilation_unit *cu, size_t stmt_list,
struct uint64_vector *file_name_table)
{
/*
* We don't care about hash flooding attacks, so don't bother with the
* random key.
*/
static const uint64_t siphash_key[2];
struct drgn_error *err;
Elf_Data *debug_line = cu->sections[SECTION_DEBUG_LINE];
const char *ptr = section_ptr(debug_line, stmt_list);
const char *end = section_end(debug_line);
struct siphash_vector directories;
siphash_vector_init(&directories);
err = skip_lnp_header(cu, &ptr, end);
if (err)
return err;
for (;;) {
struct siphash *hash;
const char *path;
size_t path_len;
if (!read_string(&ptr, end, &path, &path_len))
return drgn_eof();
if (!path_len)
break;
hash = siphash_vector_append_entry(&directories);
if (!hash) {
err = &drgn_enomem;
goto out;
}
siphash_init(hash, siphash_key);
hash_directory(hash, path, path_len);
}
for (;;) {
const char *path;
size_t path_len;
uint64_t directory_index;
struct siphash hash;
uint64_t file_name_hash;
if (!read_string(&ptr, end, &path, &path_len)) {
err = drgn_eof();
goto out;
}
if (!path_len)
break;
if ((err = read_uleb128(&ptr, end, &directory_index)))
goto out;
/* mtime, size */
if (!skip_leb128(&ptr, end) || !skip_leb128(&ptr, end)) {
err = drgn_eof();
goto out;
}
if (directory_index > directories.size) {
err = drgn_error_format(DRGN_ERROR_DWARF_FORMAT,
"directory index %" PRIu64 " is invalid",
directory_index);
goto out;
}
if (directory_index)
hash = directories.data[directory_index - 1];
else
siphash_init(&hash, siphash_key);
siphash_update(&hash, path, path_len);
file_name_hash = siphash_final(&hash);
if (!uint64_vector_append(file_name_table, &file_name_hash)) {
err = &drgn_enomem;
goto out;
}
}
err = NULL;
out:
siphash_vector_deinit(&directories);
return err;
}
static bool append_die_entry(struct drgn_dwarf_index_shard *shard, uint64_t tag,
uint64_t file_name_hash, Dwfl_Module *module,
uint64_t offset)
{
struct drgn_dwarf_index_die *die;
die = drgn_dwarf_index_die_vector_append_entry(&shard->dies);
if (!die)
return false;
die->tag = tag;
die->file_name_hash = file_name_hash;
die->module = module;
die->offset = offset;
die->next = SIZE_MAX;
return true;
}
static struct drgn_error *index_die(struct drgn_dwarf_index *dindex,
const char *name, uint64_t tag,
uint64_t file_name_hash,
Dwfl_Module *module, uint64_t offset)
{
struct drgn_error *err;
struct drgn_dwarf_index_die_map_entry entry = {
.key = {
.str = name,
.len = strlen(name),
},
};
struct hash_pair hp;
struct drgn_dwarf_index_shard *shard;
struct drgn_dwarf_index_die_map_iterator it;
size_t index;
struct drgn_dwarf_index_die *die;
hp = drgn_dwarf_index_die_map_hash(&entry.key);
shard = &dindex->shards[hash_pair_to_shard(hp)];
omp_set_lock(&shard->lock);
it = drgn_dwarf_index_die_map_search_hashed(&shard->map, &entry.key,
hp);
if (!it.entry) {
if (!append_die_entry(shard, tag, file_name_hash, module,
offset)) {
err = &drgn_enomem;
goto out;
}
entry.value = shard->dies.size - 1;
if (drgn_dwarf_index_die_map_insert_searched(&shard->map,
&entry, hp,
NULL) == 1)
err = NULL;
else
err = &drgn_enomem;
goto out;
}
die = &shard->dies.data[it.entry->value];
for (;;) {
if (die->tag == tag &&
die->file_name_hash == file_name_hash) {
err = NULL;
goto out;
}
if (die->next == SIZE_MAX)
break;
die = &shard->dies.data[die->next];
}
index = die - shard->dies.data;
if (!append_die_entry(shard, tag, file_name_hash, module, offset)) {
err = &drgn_enomem;
goto out;
}
shard->dies.data[index].next = shard->dies.size - 1;
err = NULL;
out:
omp_unset_lock(&shard->lock);
return err;
}
struct die {
const char *sibling;
const char *name;
size_t stmt_list;
size_t decl_file;
const char *specification;
uint8_t flags;
};
static struct drgn_error *read_die(struct compilation_unit *cu,
const struct abbrev_table *abbrev,
const char **ptr, const char *end,
const char *debug_str_buffer,
const char *debug_str_end, struct die *die)
{
struct drgn_error *err;
uint64_t code;
uint8_t *insnp;
uint8_t insn;
if ((err = read_uleb128(ptr, end, &code)))
return err;
if (code == 0)
return &drgn_stop;
if (code < 1 || code > abbrev->decls.size) {
return drgn_error_format(DRGN_ERROR_DWARF_FORMAT,
"unknown abbreviation code %" PRIu64,
code);
}
insnp = &abbrev->insns.data[abbrev->decls.data[code - 1]];
while ((insn = *insnp++)) {
size_t skip, tmp;
switch (insn) {
case ATTRIB_BLOCK1:
if (!read_u8_into_size_t(ptr, end, &skip))
return drgn_eof();
goto skip;
case ATTRIB_BLOCK2:
if (!read_u16_into_size_t(ptr, end, cu->bswap, &skip))
return drgn_eof();
goto skip;
case ATTRIB_BLOCK4:
if (!read_u32_into_size_t(ptr, end, cu->bswap, &skip))
return drgn_eof();
goto skip;
case ATTRIB_EXPRLOC:
if ((err = read_uleb128_into_size_t(ptr, end, &skip)))
return err;
goto skip;
case ATTRIB_LEB128:
if (!skip_leb128(ptr, end))
return drgn_eof();
break;
case ATTRIB_NAME_STRING:
die->name = *ptr;
/* fallthrough */
case ATTRIB_STRING:
if (!skip_string(ptr, end))
return drgn_eof();
break;
case ATTRIB_SIBLING_REF1:
if (!read_u8_into_size_t(ptr, end, &tmp))
return drgn_eof();
goto sibling;
case ATTRIB_SIBLING_REF2:
if (!read_u16_into_size_t(ptr, end, cu->bswap, &tmp))
return drgn_eof();
goto sibling;
case ATTRIB_SIBLING_REF4:
if (!read_u32_into_size_t(ptr, end, cu->bswap, &tmp))
return drgn_eof();
goto sibling;
case ATTRIB_SIBLING_REF8:
if (!read_u64_into_size_t(ptr, end, cu->bswap, &tmp))
return drgn_eof();
goto sibling;
case ATTRIB_SIBLING_REF_UDATA:
if ((err = read_uleb128_into_size_t(ptr, end, &tmp)))
return err;
sibling:
if (!read_in_bounds(cu->ptr, end, tmp))
return drgn_eof();
die->sibling = &cu->ptr[tmp];
__builtin_prefetch(die->sibling);
break;
case ATTRIB_NAME_STRP4:
if (!read_u32_into_size_t(ptr, end, cu->bswap, &tmp))
return drgn_eof();
goto strp;
case ATTRIB_NAME_STRP8:
if (!read_u64_into_size_t(ptr, end, cu->bswap, &tmp))
return drgn_eof();
strp:
if (!read_in_bounds(debug_str_buffer, debug_str_end,
tmp))
return drgn_eof();
die->name = &debug_str_buffer[tmp];
__builtin_prefetch(die->name);
break;
case ATTRIB_STMT_LIST_LINEPTR4:
if (!read_u32_into_size_t(ptr, end, cu->bswap,
&die->stmt_list))
return drgn_eof();
break;
case ATTRIB_STMT_LIST_LINEPTR8:
if (!read_u64_into_size_t(ptr, end, cu->bswap,
&die->stmt_list))
return drgn_eof();
break;
case ATTRIB_DECL_FILE_DATA1:
if (!read_u8_into_size_t(ptr, end, &die->decl_file))
return drgn_eof();
break;
case ATTRIB_DECL_FILE_DATA2:
if (!read_u16_into_size_t(ptr, end, cu->bswap,
&die->decl_file))
return drgn_eof();
break;
case ATTRIB_DECL_FILE_DATA4:
if (!read_u32_into_size_t(ptr, end, cu->bswap,
&die->decl_file))
return drgn_eof();
break;
case ATTRIB_DECL_FILE_DATA8:
if (!read_u64_into_size_t(ptr, end, cu->bswap,
&die->decl_file))
return drgn_eof();
break;
case ATTRIB_DECL_FILE_UDATA:
if ((err = read_uleb128_into_size_t(ptr, end,
&die->decl_file)))
return err;
break;
case ATTRIB_SPECIFICATION_REF1:
if (!read_u8_into_size_t(ptr, end, &tmp))
return drgn_eof();
goto specification;
case ATTRIB_SPECIFICATION_REF2:
if (!read_u16_into_size_t(ptr, end, cu->bswap, &tmp))
return drgn_eof();
goto specification;
case ATTRIB_SPECIFICATION_REF4:
if (!read_u32_into_size_t(ptr, end, cu->bswap, &tmp))
return drgn_eof();
goto specification;
case ATTRIB_SPECIFICATION_REF8:
if (!read_u64_into_size_t(ptr, end, cu->bswap, &tmp))
return drgn_eof();
goto specification;
case ATTRIB_SPECIFICATION_REF_UDATA:
if ((err = read_uleb128_into_size_t(ptr, end, &tmp)))
return err;
specification:
if (!read_in_bounds(cu->ptr, end, tmp))
return drgn_eof();
die->specification = &cu->ptr[tmp];
__builtin_prefetch(die->specification);
break;
default:
skip = insn;
skip:
if (!read_in_bounds(*ptr, end, skip))
return drgn_eof();
*ptr += skip;
break;
}
}
die->flags = *insnp;
return NULL;
}
static struct drgn_error *index_cu(struct drgn_dwarf_index *dindex,
struct compilation_unit *cu)
{
struct drgn_error *err;
struct abbrev_table abbrev;
struct uint64_vector file_name_table;
Elf_Data *debug_abbrev = cu->sections[SECTION_DEBUG_ABBREV];
const char *debug_abbrev_end = section_end(debug_abbrev);
const char *ptr = &cu->ptr[cu->is_64_bit ? 23 : 11];
const char *end = &cu->ptr[(cu->is_64_bit ? 12 : 4) + cu->unit_length];
Elf_Data *debug_info = cu->sections[SECTION_DEBUG_INFO];
const char *debug_info_buffer = section_ptr(debug_info, 0);
Elf_Data *debug_str = cu->sections[SECTION_DEBUG_STR];
const char *debug_str_buffer = section_ptr(debug_str, 0);
const char *debug_str_end = section_end(debug_str);
unsigned int depth = 0;
uint64_t enum_die_offset = 0;
abbrev_table_init(&abbrev);
uint64_vector_init(&file_name_table);
if ((err = read_abbrev_table(section_ptr(debug_abbrev,
cu->debug_abbrev_offset),
debug_abbrev_end, cu, &abbrev)))
goto out;
for (;;) {
struct die die = {
.stmt_list = SIZE_MAX,
};
uint64_t die_offset = ptr - debug_info_buffer;
uint64_t tag;
err = read_die(cu, &abbrev, &ptr, end, debug_str_buffer,
debug_str_end, &die);
if (err && err->code == DRGN_ERROR_STOP) {
depth--;
if (depth == 1)
enum_die_offset = 0;
else if (depth == 0)
break;
continue;
} else if (err) {
goto out;
}
tag = die.flags & TAG_MASK;
if (tag == DW_TAG_compile_unit) {
if (depth == 0 && die.stmt_list != SIZE_MAX &&
(err = read_file_name_table(dindex, cu,
die.stmt_list,
&file_name_table)))
goto out;
} else if (tag && !(die.flags & TAG_FLAG_DECLARATION)) {
uint64_t file_name_hash;
/*
* NB: the enumerator name points to the
* enumeration_type DIE instead of the enumerator DIE.
*/
if (depth == 1 && tag == DW_TAG_enumeration_type)
enum_die_offset = die_offset;
else if (depth == 2 && tag == DW_TAG_enumerator &&
enum_die_offset)
die_offset = enum_die_offset;
else if (depth != 1)
goto next;
if (die.specification && (!die.name || !die.decl_file)) {
struct die decl = {};
const char *decl_ptr = die.specification;
if ((err = read_die(cu, &abbrev, &decl_ptr, end,
debug_str_buffer,
debug_str_end, &decl)))
goto out;
if (!die.name && decl.name)
die.name = decl.name;
if (!die.decl_file && decl.decl_file)
die.decl_file = decl.decl_file;
}
if (die.name) {
if (die.decl_file > file_name_table.size) {
err = drgn_error_format(DRGN_ERROR_DWARF_FORMAT,
"invalid DW_AT_decl_file %zu",
die.decl_file);
goto out;
}
if (die.decl_file)
file_name_hash = file_name_table.data[die.decl_file - 1];
else
file_name_hash = 0;
if ((err = index_die(dindex, die.name, tag,
file_name_hash, cu->module,
die_offset)))
goto out;
}
}
next:
if (die.flags & TAG_FLAG_CHILDREN) {
if (die.sibling)
ptr = die.sibling;
else
depth++;
} else if (depth == 0) {
break;
}
}
err = NULL;
out:
uint64_vector_deinit(&file_name_table);
abbrev_table_deinit(&abbrev);
return err;
}
static struct drgn_error *index_cus(struct drgn_dwarf_index *dindex,
struct compilation_unit *cus,
size_t num_cus)
{
struct drgn_error *err = NULL;
size_t i;
#pragma omp parallel for schedule(dynamic)
for (i = 0; i < num_cus; i++) {
struct drgn_error *err2;
if (err)
continue;
err2 = index_cu(dindex, &cus[i]);
if (err2) {
#pragma omp critical(drgn_index_cus)
{
if (err)
drgn_error_destroy(err2);
else
err = err2;
}
}
}
/* If we have an error while indexing, delete all new entries. */
if (err) {
for (i = 0; i < ARRAY_SIZE(dindex->shards); i++) {
struct drgn_dwarf_index_shard *shard;
struct drgn_dwarf_index_die *die;
struct drgn_dwarf_index_die_map_iterator it;
size_t index;
shard = &dindex->shards[i];
/*
* Because we're deleting everything that was added
* since the last update, we can just shrink the dies
* array to the first entry that was added for this
* update.
*/
while (shard->dies.size) {
die = &shard->dies.data[shard->dies.size - 1];
if (drgn_dwfl_module_userdata(die->module)->indexed)
break;
else
shard->dies.size--;
}
/*
* The new entries may be chained off of existing
* entries; unchain them. Note that any entries chained
* off of the new entries must also be new, so there's
* no need to preserve them.
*/
for (index = 0; index < shard->dies.size; i++) {
die = &shard->dies.data[index];
if (die->next != SIZE_MAX &&
die->next >= shard->dies.size)
die->next = SIZE_MAX;
}
/* Finally, delete the new entries in the map. */
for (it = drgn_dwarf_index_die_map_first(&shard->map);
it.entry; ) {
if (it.entry->value >= shard->dies.size) {
it = drgn_dwarf_index_die_map_delete_iterator(&shard->map,
it);
} else {
it = drgn_dwarf_index_die_map_next(it);
}
}
}
}
return err;
}
DEFINE_VECTOR(dwfl_module_vector, Dwfl_Module *)
static int drgn_append_dwfl_module(Dwfl_Module *module, void **userdatap,
const char *name, Dwarf_Addr base, void *arg)
{
struct drgn_dwfl_module_userdata *userdata = *userdatap;
struct dwfl_module_vector *modules = arg;
if (userdata && userdata->indexed)
return DWARF_CB_OK;
if (!userdata) {
userdata = drgn_dwfl_module_userdata_create();
if (!userdata)
return DWARF_CB_ABORT;
*userdatap = userdata;
}
if (!dwfl_module_vector_append(modules, &module))
return DWARF_CB_ABORT;
return DWARF_CB_OK;
}
struct drgn_error *drgn_dwarf_index_update(struct drgn_dwarf_index *dindex,
Dwfl *dwfl)
{
struct drgn_error *err = NULL;
struct dwfl_module_vector modules;
struct compilation_unit_vector cus;
struct string_builder missing = {};
size_t num_missing = 0;
static const size_t max_missing = 5;
size_t i;
dwfl_module_vector_init(&modules);
compilation_unit_vector_init(&cus);
if (dwfl_getmodules(dwfl, drgn_append_dwfl_module, &modules, 0)) {
err = &drgn_enomem;
goto out;
}
err = apply_relocations(modules.data, modules.size);
if (err)
goto out;
err = read_cus(dindex, modules.data, modules.size, &cus);
if (err)
goto out;
err = index_cus(dindex, cus.data, cus.size);
if (err)
goto out;
for (i = 0; i < modules.size; i++) {
const char *name;
void **userdatap;
struct drgn_dwfl_module_userdata *userdata;
name = dwfl_module_info(modules.data[i], &userdatap, NULL, NULL,
NULL, NULL, NULL, NULL);
userdata = *userdatap;
if (!userdata->err) {
userdata->indexed = true;
continue;
}
if (num_missing == 0 &&
!string_builder_append(&missing,
"could not get debugging information for:")) {
err = &drgn_enomem;
goto out;
}
if (num_missing < max_missing) {
if (!string_builder_line_break(&missing) ||
!string_builder_appendf(&missing, "%s (", name) ||
!string_builder_append_error(&missing, userdata->err) ||
!string_builder_appendc(&missing, ')')) {
err = &drgn_enomem;
goto out;
}
}
num_missing++;
}
if (num_missing > max_missing &&
(!string_builder_line_break(&missing) ||
!string_builder_appendf(&missing, "... %zu more",
num_missing - max_missing))) {
err = &drgn_enomem;
goto out;
}
if (missing.len) {
err = drgn_error_from_string_builder(DRGN_ERROR_MISSING_DEBUG_INFO,
&missing);
missing.str = NULL;
} else {
err = NULL;
}
out:
free(missing.str);
compilation_unit_vector_deinit(&cus);
dwfl_module_vector_deinit(&modules);
return err;
}
static int drgn_dwfl_module_removed(Dwfl_Module *module, void *userdatap,
const char *name, Dwarf_Addr base,
void *arg)
{
/*
* userdatap is actually a void ** like for the other libdwfl callbacks,
* but dwfl_report_end() has the wrong signature for the removed
* callback.
*/
struct drgn_dwfl_module_userdata *userdata = *(void **)userdatap;
Dwarf_Addr end;
if (arg && userdata && userdata->indexed) {
/*
* The file is already indexed and drgn_remove_dwfl_modules()
* was called with unindexed == true; report the module again so
* libdwfl doesn't remove it.
*/
dwfl_module_info(module, NULL, NULL, &end, NULL, NULL, NULL,
NULL);
dwfl_report_module(arg, name, base, end);
} else {
drgn_dwfl_module_userdata_destroy(userdata);
}
return DWARF_CB_OK;
}
static void drgn_remove_dwfl_modules(Dwfl *dwfl, bool unindexed)
{
int fd;
/*
* Work around a libdwfl bug that causes it to close stdin when it frees
* some modules which are reported by dwfl_core_file_report().
*/
fd = dup(0);
dwfl_report_begin(dwfl);
dwfl_report_end(dwfl, drgn_dwfl_module_removed,
unindexed ? dwfl : NULL);
if (fd != -1) {
dup2(fd, 0);
close(fd);
}
}
void drgn_remove_unindexed_dwfl_modules(Dwfl *dwfl)
{
drgn_remove_dwfl_modules(dwfl, true);
}
void drgn_remove_all_dwfl_modules(Dwfl *dwfl)
{
drgn_remove_dwfl_modules(dwfl, false);
}
void drgn_dwarf_index_iterator_init(struct drgn_dwarf_index_iterator *it,
struct drgn_dwarf_index *dindex,
const char *name, size_t name_len,
const uint64_t *tags, size_t num_tags)
{
it->dindex = dindex;
if (name) {
struct string key = {
.str = name,
.len = name_len,
};
struct hash_pair hp;
struct drgn_dwarf_index_shard *shard;
struct drgn_dwarf_index_die_map_iterator map_it;
hp = drgn_dwarf_index_die_map_hash(&key);
it->shard = hash_pair_to_shard(hp);
shard = &dindex->shards[it->shard];
map_it = drgn_dwarf_index_die_map_search_hashed(&shard->map,
&key, hp);
it->index = map_it.entry ? map_it.entry->value : SIZE_MAX;
it->any_name = false;
} else {
it->index = 0;
for (it->shard = 0; it->shard < ARRAY_SIZE(dindex->shards);
it->shard++) {
if (dindex->shards[it->shard].dies.size)
break;
}
it->any_name = true;
}
it->tags = tags;
it->num_tags = num_tags;
}
static inline bool
drgn_dwarf_index_iterator_matches_tag(struct drgn_dwarf_index_iterator *it,
struct drgn_dwarf_index_die *die)
{
size_t i;
if (it->num_tags == 0)
return true;
for (i = 0; i < it->num_tags; i++) {
if (die->tag == it->tags[i])
return true;
}
return false;
}
struct drgn_error *
drgn_dwarf_index_iterator_next(struct drgn_dwarf_index_iterator *it,
Dwarf_Die *die_ret, uint64_t *bias_ret)
{
struct drgn_dwarf_index *dindex = it->dindex;
struct drgn_dwarf_index_die *die;
Dwarf *dwarf;
Dwarf_Addr bias;
if (it->any_name) {
for (;;) {
struct drgn_dwarf_index_shard *shard;
if (it->shard >= ARRAY_SIZE(dindex->shards))
return &drgn_stop;
shard = &dindex->shards[it->shard];
die = &shard->dies.data[it->index];
if (++it->index >= shard->dies.size) {
it->index = 0;
while (++it->shard < ARRAY_SIZE(dindex->shards)) {
if (dindex->shards[it->shard].dies.size)
break;
}
}
if (drgn_dwarf_index_iterator_matches_tag(it, die))
break;
}
} else {
for (;;) {
struct drgn_dwarf_index_shard *shard;
if (it->index == SIZE_MAX)
return &drgn_stop;
shard = &dindex->shards[it->shard];
die = &shard->dies.data[it->index];
it->index = die->next;
if (drgn_dwarf_index_iterator_matches_tag(it, die))
break;
}
}
dwarf = dwfl_module_getdwarf(die->module, &bias);
if (!dwarf)
return drgn_error_libdwfl();
if (!dwarf_offdie(dwarf, die->offset, die_ret))
return drgn_error_libdw();
if (bias_ret)
*bias_ret = bias;
return NULL;
}
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