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c8406e1ea0
drgn/libdrgn/linux_kernel.c
Omar Sandoval c8406e1ea0 libdrgn: require semicolon after DEFINE_{HASH,VECTOR,BINARY_SEARCH_TREE}* 
The lack of a semicolon after these macros has always confused tooling
like cscope. We could add semicolons everywhere now, but let's enforce
it for the future, too. Let's add a dummy struct forward declaration at
the end of each macro that enforces this requirement and also provides a
useful error message.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2023-08-02 14:54:59 -07:00

1785 lines
46 KiB
C
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// Copyright (c) Meta Platforms, Inc. and affiliates.
// SPDX-License-Identifier: LGPL-2.1-or-later
#include <byteswap.h>
#include <dirent.h>
#include <elf.h>
#include <elfutils/libdwelf.h>
#include <errno.h>
#include <fcntl.h>
#include <gelf.h>
#include <inttypes.h>
#include <libelf.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include "binary_buffer.h"
#include "cleanup.h"
#include "debug_info.h"
#include "drgn.h"
#include "error.h"
#include "hash_table.h"
#include "helpers.h"
#include "io.h"
#include "linux_kernel.h"
#include "platform.h"
#include "program.h"
#include "type.h"
#include "util.h"
#include "drgn_program_parse_vmcoreinfo.inc"
struct drgn_error *read_memory_via_pgtable(void *buf, uint64_t address,
size_t count, uint64_t offset,
void *arg, bool physical)
{
struct drgn_program *prog = arg;
return linux_helper_read_vm(prog, prog->vmcoreinfo.swapper_pg_dir,
address, buf, count);
}
struct drgn_error *proc_kallsyms_symbol_addr(const char *name,
unsigned long *ret)
{
struct drgn_error *err;
FILE *file;
char *line = NULL;
size_t n = 0;
file = fopen("/proc/kallsyms", "r");
if (!file)
return drgn_error_create_os("fopen", errno, "/proc/kallsyms");
for (;;) {
char *addr_str, *sym_str, *saveptr, *end;
errno = 0;
if (getline(&line, &n, file) == -1) {
if (errno) {
err = drgn_error_create_os("getline", errno,
"/proc/kallsyms");
} else {
err = &drgn_not_found;
}
break;
}
addr_str = strtok_r(line, "\t ", &saveptr);
if (!addr_str || !*addr_str)
goto invalid;
if (!strtok_r(NULL, "\t ", &saveptr))
goto invalid;
sym_str = strtok_r(NULL, "\t\n ", &saveptr);
if (!sym_str)
goto invalid;
if (strcmp(sym_str, name) != 0)
continue;
errno = 0;
*ret = strtoul(line, &end, 16);
if (errno || *end) {
invalid:
err = drgn_error_create(DRGN_ERROR_OTHER,
"could not parse /proc/kallsyms");
break;
}
err = NULL;
break;
}
free(line);
fclose(file);
return err;
}
/*
* Before Linux kernel commit 23c85094fe18 ("proc/kcore: add vmcoreinfo note to
* /proc/kcore") (in v4.19), /proc/kcore didn't have a VMCOREINFO note. Instead,
* we can read from the physical address of the vmcoreinfo note exported in
* sysfs.
*/
struct drgn_error *read_vmcoreinfo_fallback(struct drgn_program *prog)
{
struct drgn_error *err;
FILE *file;
uint64_t address;
size_t size;
Elf64_Nhdr *nhdr;
file = fopen("/sys/kernel/vmcoreinfo", "r");
if (!file) {
return drgn_error_create_os("fopen", errno,
"/sys/kernel/vmcoreinfo");
}
if (fscanf(file, "%" SCNx64 "%zx", &address, &size) != 2) {
fclose(file);
return drgn_error_create(DRGN_ERROR_OTHER,
"could not parse /sys/kernel/vmcoreinfo");
}
fclose(file);
_cleanup_free_ char *buf = malloc(size);
if (!buf)
return &drgn_enomem;
err = drgn_program_read_memory(prog, buf, address, size, true);
if (err)
return err;
/*
* The first 12 bytes are the Elf{32,64}_Nhdr (it's the same in both
* formats). The name is padded up to 4 bytes, so the descriptor starts
* at byte 24.
*/
nhdr = (Elf64_Nhdr *)buf;
if (size < 24 || nhdr->n_namesz != 11 ||
memcmp(buf + sizeof(*nhdr), "VMCOREINFO", 10) != 0 ||
nhdr->n_descsz > size - 24) {
err = drgn_error_create(DRGN_ERROR_OTHER,
"VMCOREINFO is invalid");
return err;
}
return drgn_program_parse_vmcoreinfo(prog, buf + 24, nhdr->n_descsz);
}
static struct drgn_error *linux_kernel_get_page_shift(struct drgn_program *prog,
struct drgn_object *ret)
{
struct drgn_error *err;
struct drgn_qualified_type qualified_type;
err = drgn_program_find_primitive_type(prog, DRGN_C_TYPE_INT,
&qualified_type.type);
if (err)
return err;
qualified_type.qualifiers = 0;
return drgn_object_set_signed(ret, qualified_type,
prog->vmcoreinfo.page_shift, 0);
}
static struct drgn_error *linux_kernel_get_page_size(struct drgn_program *prog,
struct drgn_object *ret)
{
struct drgn_error *err;
struct drgn_qualified_type qualified_type;
err = drgn_program_find_primitive_type(prog, DRGN_C_TYPE_UNSIGNED_LONG,
&qualified_type.type);
if (err)
return err;
qualified_type.qualifiers = 0;
return drgn_object_set_unsigned(ret, qualified_type,
prog->vmcoreinfo.page_size, 0);
}
static struct drgn_error *linux_kernel_get_page_mask(struct drgn_program *prog,
struct drgn_object *ret)
{
struct drgn_error *err;
struct drgn_qualified_type qualified_type;
err = drgn_program_find_primitive_type(prog, DRGN_C_TYPE_UNSIGNED_LONG,
&qualified_type.type);
if (err)
return err;
qualified_type.qualifiers = 0;
return drgn_object_set_unsigned(ret, qualified_type,
~(prog->vmcoreinfo.page_size - 1), 0);
}
static struct drgn_error *
linux_kernel_get_uts_release(struct drgn_program *prog, struct drgn_object *ret)
{
struct drgn_error *err;
struct drgn_qualified_type qualified_type;
err = drgn_program_find_primitive_type(prog,
DRGN_C_TYPE_CHAR,
&qualified_type.type);
if (err)
return err;
qualified_type.qualifiers = DRGN_QUALIFIER_CONST;
size_t len = strlen(prog->vmcoreinfo.osrelease);
err = drgn_array_type_create(prog, qualified_type, len + 1,
&drgn_language_c, &qualified_type.type);
if (err)
return err;
qualified_type.qualifiers = 0;
return drgn_object_set_from_buffer(ret, qualified_type,
prog->vmcoreinfo.osrelease, len + 1,
0, 0);
}
// jiffies is defined as an alias of jiffies_64 via the Linux kernel linker
// script, so it is not included in debug info.
static struct drgn_error *linux_kernel_get_jiffies(struct drgn_program *prog,
struct drgn_object *ret)
{
struct drgn_error *err;
struct drgn_object jiffies_64;
drgn_object_init(&jiffies_64, prog);
err = drgn_program_find_object(prog, "jiffies_64", NULL,
DRGN_FIND_OBJECT_VARIABLE, &jiffies_64);
if (err) {
if (err->code == DRGN_ERROR_LOOKUP) {
drgn_error_destroy(err);
err = &drgn_not_found;
}
goto out;
}
if (jiffies_64.kind != DRGN_OBJECT_REFERENCE) {
err = &drgn_not_found;
goto out;
}
uint64_t address = jiffies_64.address;
struct drgn_qualified_type qualified_type;
err = drgn_program_find_primitive_type(prog, DRGN_C_TYPE_UNSIGNED_LONG,
&qualified_type.type);
if (err)
return err;
qualified_type.qualifiers = DRGN_QUALIFIER_VOLATILE;
if (drgn_type_size(qualified_type.type) == 4 &&
!drgn_type_little_endian(qualified_type.type))
address += 4;
err = drgn_object_set_reference(ret, qualified_type, address, 0, 0);
out:
drgn_object_deinit(&jiffies_64);
return err;
}
// The vmemmap address can vary depending on architecture, kernel version,
// configuration options, and KASLR. However, we can get it generically from the
// section_mem_map of any valid mem_section.
static struct drgn_error *
linux_kernel_get_vmemmap_address(struct drgn_program *prog, uint64_t *ret)
{
static const uint64_t SECTION_HAS_MEM_MAP = 0x2;
static const uint64_t SECTION_MAP_MASK = ~((UINT64_C(1) << 6) - 1);
struct drgn_error *err;
struct drgn_object mem_section, root, section;
drgn_object_init(&mem_section, prog);
drgn_object_init(&root, prog);
drgn_object_init(&section, prog);
err = drgn_program_find_object(prog, "vmemmap_populate", NULL,
DRGN_FIND_OBJECT_FUNCTION, &mem_section);
if (err) {
if (err->code == DRGN_ERROR_LOOKUP) {
// !CONFIG_SPARSEMEM_VMEMMAP
drgn_error_destroy(err);
err = &drgn_not_found;
}
goto out;
}
err = drgn_program_find_object(prog, "mem_section", NULL,
DRGN_FIND_OBJECT_VARIABLE, &mem_section);
if (err)
goto out;
const uint64_t nr_section_roots = prog->vmcoreinfo.mem_section_length;
uint64_t sections_per_root;
if (drgn_type_kind(mem_section.type) == DRGN_TYPE_ARRAY) {
// If !CONFIG_SPARSEMEM_EXTREME, mem_section is
// struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT],
// and SECTIONS_PER_ROOT is 1.
sections_per_root = 1;
} else {
// If CONFIG_SPARSEMEM_EXTREME, mem_section is
// struct mem_section **mem_section, and SECTIONS_PER_ROOT is
// PAGE_SIZE / sizeof(struct mem_section).
struct drgn_type *mem_section_type = mem_section.type;
for (int i = 0; i < 2; i++) {
if (drgn_type_kind(mem_section_type) != DRGN_TYPE_POINTER) {
unrecognized_mem_section_type:
err = drgn_type_error("mem_section has unrecognized type '%s'",
mem_section.type);
goto out;
}
mem_section_type = drgn_type_type(mem_section_type).type;
}
if (drgn_type_kind(mem_section_type) != DRGN_TYPE_STRUCT)
goto unrecognized_mem_section_type;
uint64_t sizeof_mem_section = drgn_type_size(mem_section_type);
if (sizeof_mem_section == 0)
goto unrecognized_mem_section_type;
sections_per_root =
prog->vmcoreinfo.page_size / sizeof_mem_section;
}
// Find a valid section.
for (uint64_t i = 0; i < nr_section_roots; i++) {
err = drgn_object_subscript(&root, &mem_section, i);
if (err)
goto out;
bool truthy;
err = drgn_object_bool(&root, &truthy);
if (err)
goto out;
if (!truthy)
continue;
for (uint64_t j = 0; j < sections_per_root; j++) {
err = drgn_object_subscript(&section, &root, j);
if (err)
goto out;
err = drgn_object_member(&section, &section,
"section_mem_map");
if (err)
goto out;
uint64_t section_mem_map;
err = drgn_object_read_unsigned(&section,
&section_mem_map);
if (err)
goto out;
if (section_mem_map & SECTION_HAS_MEM_MAP) {
*ret = section_mem_map & SECTION_MAP_MASK;
err = NULL;
goto out;
}
}
}
err = &drgn_not_found;
out:
drgn_object_deinit(&section);
drgn_object_deinit(&root);
drgn_object_deinit(&mem_section);
return err;
}
static struct drgn_error *linux_kernel_get_vmemmap(struct drgn_program *prog,
struct drgn_object *ret)
{
struct drgn_error *err;
if (prog->vmemmap.kind == DRGN_OBJECT_ABSENT) {
// Silence -Wmaybe-uninitialized false positive last seen with
// GCC 13 by initializing to zero.
uint64_t address = 0;
err = linux_kernel_get_vmemmap_address(prog, &address);
if (err)
return err;
struct drgn_qualified_type qualified_type;
err = drgn_program_find_type(prog, "struct page *", NULL,
&qualified_type);
if (err)
return err;
err = drgn_object_set_unsigned(&prog->vmemmap, qualified_type,
address, 0);
if (err)
return err;
}
return drgn_object_copy(ret, &prog->vmemmap);
}
#include "linux_kernel_object_find.inc" // IWYU pragma: keep
struct kernel_module_iterator {
char *name;
uint64_t start, end;
void *build_id_buf;
size_t build_id_buf_capacity;
/* `struct module` type. */
struct drgn_qualified_type module_type;
/* Current `struct module` (not a pointer). */
struct drgn_object mod;
/* `struct list_head *` in next module to return. */
struct drgn_object node;
/* Temporary objects reused for various purposes. */
struct drgn_object tmp1, tmp2, tmp3;
/* Address of `struct list_head modules`. */
uint64_t head;
bool use_sys_module;
};
static void kernel_module_iterator_deinit(struct kernel_module_iterator *it)
{
drgn_object_deinit(&it->tmp3);
drgn_object_deinit(&it->tmp2);
drgn_object_deinit(&it->tmp1);
drgn_object_deinit(&it->node);
drgn_object_deinit(&it->mod);
free(it->build_id_buf);
free(it->name);
}
static struct drgn_error *
kernel_module_iterator_init(struct kernel_module_iterator *it,
struct drgn_program *prog, bool use_sys_module)
{
struct drgn_error *err;
it->name = NULL;
it->build_id_buf = NULL;
it->build_id_buf_capacity = 0;
it->use_sys_module = use_sys_module;
err = drgn_program_find_type(prog, "struct module", NULL,
&it->module_type);
if (err)
return err;
drgn_object_init(&it->mod, prog);
drgn_object_init(&it->node, prog);
drgn_object_init(&it->tmp1, prog);
drgn_object_init(&it->tmp2, prog);
drgn_object_init(&it->tmp3, prog);
err = drgn_program_find_object(prog, "modules", NULL,
DRGN_FIND_OBJECT_VARIABLE, &it->node);
if (err)
goto err;
if (it->node.kind != DRGN_OBJECT_REFERENCE) {
err = drgn_error_create(DRGN_ERROR_OTHER,
"can't get address of modules list");
goto err;
}
it->head = it->node.address;
err = drgn_object_member(&it->node, &it->node, "next");
if (err)
goto err;
err = drgn_object_read(&it->node, &it->node);
if (err)
goto err;
return NULL;
err:
kernel_module_iterator_deinit(it);
return err;
}
/**
* Get the the next loaded kernel module.
*
* After this is called, @c it->name is set to the name of the kernel module,
* and @c it->start and @c it->end are set to the address range of the kernel
* module. These are valid until the next time this is called or the iterator is
* destroyed.
*
* @return @c NULL on success, non-@c NULL on error. In particular, when there
* are no more modules, returns &@ref drgn_stop.
*/
static struct drgn_error *
kernel_module_iterator_next(struct kernel_module_iterator *it)
{
struct drgn_error *err;
uint64_t addr;
err = drgn_object_read_unsigned(&it->node, &addr);
if (err)
return err;
if (addr == it->head)
return &drgn_stop;
err = drgn_object_container_of(&it->mod, &it->node, it->module_type,
"list");
if (err)
return err;
err = drgn_object_dereference(&it->mod, &it->mod);
if (err)
return err;
// We need several fields from the `struct module`. Especially for
// /proc/kcore, it is faster to read the entire structure (which is <1kB
// as of Linux 6.0) from the core dump all at once than it is to read
// each field individually.
err = drgn_object_read(&it->mod, &it->mod);
if (err)
return err;
err = drgn_object_member(&it->node, &it->mod, "list");
if (err)
return err;
err = drgn_object_member(&it->node, &it->node, "next");
if (err)
return err;
// Set tmp1 to the module base address and tmp2 to the size.
err = drgn_object_member(&it->tmp1, &it->mod, "mem");
if (!err) {
union drgn_value mod_mem_type;
// Since Linux kernel commit ac3b43283923 ("module: replace
// module_layout with module_memory") (in v6.4), the base and
// size are in the `struct module_memory mem[MOD_TEXT]` member
// of `struct module`.
err = drgn_program_find_object(drgn_object_program(&it->mod),
"MOD_TEXT", NULL,
DRGN_FIND_OBJECT_CONSTANT,
&it->tmp2);
if (err)
return err;
err = drgn_object_read_integer(&it->tmp2, &mod_mem_type);
if (err)
return err;
err = drgn_object_subscript(&it->tmp1, &it->tmp1,
mod_mem_type.uvalue);
if (err)
return err;
err = drgn_object_member(&it->tmp2, &it->tmp1, "size");
if (err)
return err;
err = drgn_object_member(&it->tmp1, &it->tmp1, "base");
if (err)
return err;
} else if (err->code == DRGN_ERROR_LOOKUP) {
// Since Linux kernel commit 7523e4dc5057 ("module: use a
// structure to encapsulate layout.") (in v4.5), the base and
// size are in the `struct module_layout core_layout` member of
// `struct module`.
drgn_error_destroy(err);
err = drgn_object_member(&it->tmp1, &it->mod, "core_layout");
if (!err) {
err = drgn_object_member(&it->tmp2, &it->tmp1, "size");
if (err)
return err;
err = drgn_object_member(&it->tmp1, &it->tmp1, "base");
if (err)
return err;
} else if (err->code == DRGN_ERROR_LOOKUP) {
// Before that, they are directly in the `struct
// module`.
drgn_error_destroy(err);
err = drgn_object_member(&it->tmp2, &it->mod,
"core_size");
if (err)
return err;
err = drgn_object_member(&it->tmp1, &it->mod,
"module_core");
if (err)
return err;
} else {
return err;
}
} else {
return err;
}
err = drgn_object_read_unsigned(&it->tmp1, &it->start);
if (err)
return err;
err = drgn_object_read_unsigned(&it->tmp2, &it->end);
if (err)
return err;
it->end += it->start;
err = drgn_object_member(&it->tmp2, &it->mod, "name");
if (err)
return err;
char *name;
err = drgn_object_read_c_string(&it->tmp2, &name);
if (err)
return err;
free(it->name);
it->name = name;
return NULL;
}
static size_t parse_gnu_build_id_from_note(const void *note, size_t note_size,
bool bswap, const void **ret)
{
const char *p = note;
const char *end = p + note_size;
// Elf64_Nhdr is the same as Elf32_Nhdr.
Elf32_Nhdr nhdr;
while (end - p >= sizeof(nhdr)) {
#define ALIGN_NOTE() do { \
size_t to_align = (size_t)-(p - (char *)note) % 4; \
if (to_align > end - p) \
break; \
p += to_align; \
} while (0)
memcpy(&nhdr, p, sizeof(nhdr));
if (bswap) {
nhdr.n_namesz = bswap_32(nhdr.n_namesz);
nhdr.n_descsz = bswap_32(nhdr.n_descsz);
nhdr.n_type = bswap_32(nhdr.n_type);
}
p += sizeof(nhdr);
if (nhdr.n_namesz > end - p)
break;
const char *name = p;
p += nhdr.n_namesz;
ALIGN_NOTE();
if (nhdr.n_namesz == sizeof("GNU") &&
memcmp(name, "GNU", sizeof("GNU")) == 0 &&
nhdr.n_type == NT_GNU_BUILD_ID &&
nhdr.n_descsz > 0) {
if (nhdr.n_descsz > end - p)
break;
*ret = p;
return nhdr.n_descsz;
}
p += nhdr.n_descsz;
ALIGN_NOTE();
#undef ALIGN_NOTE
}
*ret = NULL;
return 0;
}
static struct drgn_error *
kernel_module_iterator_gnu_build_id_live(struct kernel_module_iterator *it,
const void **build_id_ret,
size_t *build_id_len_ret)
{
struct drgn_error *err;
char *path;
if (asprintf(&path, "/sys/module/%s/notes", it->name) == -1)
return &drgn_enomem;
DIR *dir = opendir(path);
if (!dir) {
err = drgn_error_create_os("opendir", errno, path);
goto out_path;
}
struct dirent *ent;
while ((errno = 0, ent = readdir(dir))) {
if (ent->d_type == DT_DIR)
continue;
int fd = openat(dirfd(dir), ent->d_name, O_RDONLY);
if (fd == -1) {
err = drgn_error_format_os("openat", errno, "%s/%s",
path, ent->d_name);
goto out;
}
struct stat st;
if (fstat(fd, &st) < 0) {
err = drgn_error_format_os("fstat", errno, "%s/%s",
path, ent->d_name);
close(fd);
goto out;
}
if (st.st_size > SIZE_MAX ||
!alloc_or_reuse(&it->build_id_buf,
&it->build_id_buf_capacity, st.st_size)) {
err = &drgn_enomem;
close(fd);
goto out;
}
ssize_t r = read_all(fd, it->build_id_buf, st.st_size);
if (r < 0) {
err = drgn_error_format_os("read", errno, "%s/%s", path,
ent->d_name);
close(fd);
goto out;
}
close(fd);
*build_id_len_ret =
parse_gnu_build_id_from_note(it->build_id_buf, r, false,
build_id_ret);
if (*build_id_len_ret) {
err = NULL;
goto out;
}
}
if (errno) {
err = drgn_error_create_os("readdir", errno, path);
} else {
*build_id_ret = NULL;
*build_id_len_ret = 0;
err = NULL;
}
out:
closedir(dir);
out_path:
free(path);
return err;
}
static struct drgn_error *
kernel_module_iterator_gnu_build_id(struct kernel_module_iterator *it,
const void **build_id_ret,
size_t *build_id_len_ret)
{
if (it->use_sys_module) {
return kernel_module_iterator_gnu_build_id_live(it,
build_id_ret,
build_id_len_ret);
}
struct drgn_error *err;
struct drgn_program *prog = drgn_object_program(&it->mod);
const bool bswap = drgn_platform_bswap(&prog->platform);
struct drgn_object attrs, attr, tmp;
drgn_object_init(&attrs, prog);
drgn_object_init(&attr, prog);
drgn_object_init(&tmp, prog);
// n = mod->notes_attrs->notes
uint64_t n;
err = drgn_object_member(&attrs, &it->mod, "notes_attrs");
if (err)
goto out;
err = drgn_object_member_dereference(&tmp, &attrs, "notes");
if (err)
goto out;
err = drgn_object_read_unsigned(&tmp, &n);
if (err)
goto out;
// attrs = mod->notes_attrs->attrs
err = drgn_object_member_dereference(&attrs, &attrs, "attrs");
if (err)
goto out;
for (uint64_t i = 0; i < n; i++) {
// attr = attrs[i]
err = drgn_object_subscript(&attr, &attrs, i);
if (err)
goto out;
// address = attr.private
err = drgn_object_member(&tmp, &attr, "private");
if (err)
goto out;
uint64_t address;
err = drgn_object_read_unsigned(&tmp, &address);
if (err)
goto out;
// size = attr.size
err = drgn_object_member(&tmp, &attr, "size");
if (err)
goto out;
uint64_t size;
err = drgn_object_read_unsigned(&tmp, &size);
if (err)
goto out;
if (size > SIZE_MAX ||
!alloc_or_reuse(&it->build_id_buf,
&it->build_id_buf_capacity, size)) {
err = &drgn_enomem;
goto out;
}
err = drgn_program_read_memory(prog, it->build_id_buf, address,
size, false);
if (err)
goto out;
*build_id_len_ret =
parse_gnu_build_id_from_note(it->build_id_buf, size,
bswap, build_id_ret);
if (*build_id_len_ret) {
err = NULL;
goto out;
}
}
*build_id_ret = NULL;
*build_id_len_ret = 0;
err = NULL;
out:
drgn_object_deinit(&tmp);
drgn_object_deinit(&attr);
drgn_object_deinit(&attrs);
return err;
}
struct kernel_module_section_iterator {
struct kernel_module_iterator *kmod_it;
bool yielded_percpu;
/* /sys/module/$module/sections directory or NULL. */
DIR *sections_dir;
/* If not using /sys/module/$module/sections. */
uint64_t i;
uint64_t nsections;
char *name;
};
static struct drgn_error *
kernel_module_section_iterator_init(struct kernel_module_section_iterator *it,
struct kernel_module_iterator *kmod_it)
{
struct drgn_error *err;
it->kmod_it = kmod_it;
it->yielded_percpu = false;
if (kmod_it->use_sys_module) {
char *path;
if (asprintf(&path, "/sys/module/%s/sections",
kmod_it->name) == -1)
return &drgn_enomem;
it->sections_dir = opendir(path);
free(path);
if (!it->sections_dir) {
return drgn_error_format_os("opendir", errno,
"/sys/module/%s/sections",
kmod_it->name);
}
return NULL;
} else {
it->sections_dir = NULL;
it->i = 0;
it->name = NULL;
/* it->nsections = mod->sect_attrs->nsections */
err = drgn_object_member(&kmod_it->tmp1, &kmod_it->mod,
"sect_attrs");
if (err)
return err;
err = drgn_object_member_dereference(&kmod_it->tmp2,
&kmod_it->tmp1,
"nsections");
if (err)
return err;
err = drgn_object_read_unsigned(&kmod_it->tmp2,
&it->nsections);
if (err)
return err;
/* kmod_it->tmp1 = mod->sect_attrs->attrs */
return drgn_object_member_dereference(&kmod_it->tmp1,
&kmod_it->tmp1, "attrs");
}
}
static void
kernel_module_section_iterator_deinit(struct kernel_module_section_iterator *it)
{
if (it->sections_dir)
closedir(it->sections_dir);
else
free(it->name);
}
static struct drgn_error *
kernel_module_section_iterator_next_live(struct kernel_module_section_iterator *it,
const char **name_ret,
uint64_t *address_ret)
{
struct dirent *ent;
while ((errno = 0, ent = readdir(it->sections_dir))) {
if (ent->d_type == DT_DIR)
continue;
if (ent->d_type == DT_UNKNOWN) {
struct stat st;
if (fstatat(dirfd(it->sections_dir), ent->d_name, &st,
0) == -1) {
return drgn_error_format_os("fstatat", errno,
"/sys/module/%s/sections/%s",
it->kmod_it->name,
ent->d_name);
}
if (S_ISDIR(st.st_mode))
continue;
}
int fd = openat(dirfd(it->sections_dir), ent->d_name, O_RDONLY);
if (fd == -1) {
return drgn_error_format_os("openat", errno,
"/sys/module/%s/sections/%s",
it->kmod_it->name,
ent->d_name);
}
FILE *file = fdopen(fd, "r");
if (!file) {
close(fd);
return drgn_error_create_os("fdopen", errno, NULL);
}
int ret = fscanf(file, "%" SCNx64, address_ret);
fclose(file);
if (ret != 1) {
return drgn_error_format(DRGN_ERROR_OTHER,
"could not parse /sys/module/%s/sections/%s",
it->kmod_it->name,
ent->d_name);
}
*name_ret = ent->d_name;
return NULL;
}
if (errno) {
return drgn_error_format_os("readdir", errno,
"/sys/module/%s/sections",
it->kmod_it->name);
} else {
return &drgn_stop;
}
}
static struct drgn_error *
kernel_module_section_iterator_next(struct kernel_module_section_iterator *it,
const char **name_ret,
uint64_t *address_ret)
{
struct drgn_error *err;
struct kernel_module_iterator *kmod_it = it->kmod_it;
// As of Linux 6.0, the .data..percpu section is not included in the
// section attributes. (kernel/module/sysfs.c:add_sect_attrs() only
// creates attributes for sections with the SHF_ALLOC flag set, but
// kernel/module/main.c:layout_and_allocate() clears the SHF_ALLOC flag
// for the .data..percpu section.) However, we need this address so that
// global per-CPU variables will be relocated correctly. Get it from
// `struct module`.
if (!it->yielded_percpu) {
it->yielded_percpu = true;
err = drgn_object_member(&kmod_it->tmp2, &kmod_it->mod,
"percpu");
if (!err) {
err = drgn_object_read_unsigned(&kmod_it->tmp2, address_ret);
if (err)
return err;
// struct module::percpu is NULL if the module doesn't
// have any per-CPU data.
if (*address_ret) {
*name_ret = ".data..percpu";
return NULL;
}
} else if (err->code == DRGN_ERROR_LOOKUP) {
// struct module::percpu doesn't exist if !SMP.
drgn_error_destroy(err);
} else {
return err;
}
}
if (it->sections_dir) {
return kernel_module_section_iterator_next_live(it, name_ret,
address_ret);
}
if (it->i >= it->nsections)
return &drgn_stop;
err = drgn_object_subscript(&kmod_it->tmp2, &kmod_it->tmp1, it->i++);
if (err)
return err;
err = drgn_object_member(&kmod_it->tmp3, &kmod_it->tmp2, "address");
if (err)
return err;
err = drgn_object_read_unsigned(&kmod_it->tmp3, address_ret);
if (err)
return err;
/*
* Since Linux kernel commit ed66f991bb19 ("module: Refactor section
* attr into bin attribute") (in v5.8), the section name is
* module_sect_attr.battr.attr.name. Before that, it is simply
* module_sect_attr.name.
*/
err = drgn_object_member(&kmod_it->tmp2, &kmod_it->tmp2, "battr");
if (!err) {
err = drgn_object_member(&kmod_it->tmp2, &kmod_it->tmp2,
"attr");
if (err)
return err;
} else {
if (err->code != DRGN_ERROR_LOOKUP)
return err;
drgn_error_destroy(err);
}
err = drgn_object_member(&kmod_it->tmp3, &kmod_it->tmp2, "name");
if (err)
return err;
char *name;
err = drgn_object_read_c_string(&kmod_it->tmp3, &name);
if (err)
return err;
free(it->name);
*name_ret = it->name = name;
return NULL;
}
/*
* /lib/modules/$(uname -r)/modules.dep.bin maps all installed kernel modules to
* their filesystem path (and dependencies, which we don't care about). It is
* generated by depmod; the format is a fairly simple serialized radix tree.
*
* modules.dep(5) contains a warning: "These files are not intended for editing
* or use by any additional utilities as their format is subject to change in
* the future." But, the format hasn't changed since 2009, and pulling in
* libkmod is overkill since we only need a very small subset of its
* functionality (plus our minimal parser is more efficient). If the format
* changes in the future, we can reevaluate this.
*/
struct depmod_index {
void *addr;
size_t len;
char path[256];
};
static void depmod_index_deinit(struct depmod_index *depmod)
{
munmap(depmod->addr, depmod->len);
}
struct depmod_index_buffer {
struct binary_buffer bb;
struct depmod_index *depmod;
};
static struct drgn_error *depmod_index_buffer_error(struct binary_buffer *bb,
const char *pos,
const char *message)
{
struct depmod_index_buffer *buffer =
container_of(bb, struct depmod_index_buffer, bb);
return drgn_error_format(DRGN_ERROR_OTHER, "%s: %#tx: %s",
buffer->depmod->path,
pos - (const char *)buffer->depmod->addr,
message);
}
static void depmod_index_buffer_init(struct depmod_index_buffer *buffer,
struct depmod_index *depmod)
{
binary_buffer_init(&buffer->bb, depmod->addr, depmod->len, false,
depmod_index_buffer_error);
buffer->depmod = depmod;
}
static struct drgn_error *depmod_index_validate(struct depmod_index *depmod)
{
struct drgn_error *err;
struct depmod_index_buffer buffer;
depmod_index_buffer_init(&buffer, depmod);
uint32_t magic;
if ((err = binary_buffer_next_u32(&buffer.bb, &magic)))
return err;
if (magic != 0xb007f457) {
return binary_buffer_error(&buffer.bb,
"invalid magic 0x%" PRIx32, magic);
}
uint32_t version;
if ((err = binary_buffer_next_u32(&buffer.bb, &version)))
return err;
if (version != 0x00020001) {
return binary_buffer_error(&buffer.bb,
"unknown version 0x%" PRIx32,
version);
}
return NULL;
}
static struct drgn_error *depmod_index_init(struct depmod_index *depmod,
const char *osrelease)
{
struct drgn_error *err;
snprintf(depmod->path, sizeof(depmod->path),
"/lib/modules/%s/modules.dep.bin", osrelease);
int fd = open(depmod->path, O_RDONLY);
if (fd == -1)
return drgn_error_create_os("open", errno, depmod->path);
struct stat st;
if (fstat(fd, &st) == -1) {
err = drgn_error_create_os("fstat", errno, depmod->path);
goto out;
}
if (st.st_size < 0 || st.st_size > SIZE_MAX) {
err = &drgn_enomem;
goto out;
}
void *addr = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (addr == MAP_FAILED) {
err = drgn_error_create_os("mmap", errno, depmod->path);
goto out;
}
depmod->addr = addr;
depmod->len = st.st_size;
err = depmod_index_validate(depmod);
if (err)
depmod_index_deinit(depmod);
out:
close(fd);
return err;
}
/*
* Look up the path of the kernel module with the given name.
*
* @param[in] name Name of the kernel module.
* @param[out] path_ret Returned path of the kernel module, relative to
* /lib/modules/$(uname -r). This is @em not null-terminated. @c NULL if not
* found.
* @param[out] len_ret Returned length of @p path_ret.
*/
static struct drgn_error *depmod_index_find(struct depmod_index *depmod,
const char *name,
const char **path_ret,
size_t *len_ret)
{
static const uint32_t INDEX_NODE_MASK = UINT32_C(0x0fffffff);
static const uint32_t INDEX_NODE_CHILDS = UINT32_C(0x20000000);
static const uint32_t INDEX_NODE_VALUES = UINT32_C(0x40000000);
static const uint32_t INDEX_NODE_PREFIX = UINT32_C(0x80000000);
struct drgn_error *err;
struct depmod_index_buffer buffer;
depmod_index_buffer_init(&buffer, depmod);
/* depmod_index_validate() already checked that this is within bounds. */
buffer.bb.pos += 8;
uint32_t offset;
for (;;) {
if ((err = binary_buffer_next_u32(&buffer.bb, &offset)))
return err;
if ((offset & INDEX_NODE_MASK) > depmod->len) {
return binary_buffer_error(&buffer.bb,
"offset is out of bounds");
}
buffer.bb.pos = (const char *)depmod->addr + (offset & INDEX_NODE_MASK);
if (offset & INDEX_NODE_PREFIX) {
const char *prefix;
size_t prefix_len;
if ((err = binary_buffer_next_string(&buffer.bb,
&prefix,
&prefix_len)))
return err;
if (strncmp(name, prefix, prefix_len) != 0)
goto not_found;
name += prefix_len;
}
if (offset & INDEX_NODE_CHILDS) {
uint8_t first, last;
if ((err = binary_buffer_next_u8(&buffer.bb, &first)) ||
(err = binary_buffer_next_u8(&buffer.bb, &last)))
return err;
if (*name) {
uint8_t cur = *name;
if (cur < first || cur > last)
goto not_found;
if ((err = binary_buffer_skip(&buffer.bb,
4 * (cur - first))))
return err;
name++;
continue;
} else {
if ((err = binary_buffer_skip(&buffer.bb,
4 * (last - first + 1))))
return err;
break;
}
} else if (*name) {
goto not_found;
} else {
break;
}
}
if (!(offset & INDEX_NODE_VALUES))
goto not_found;
uint32_t value_count;
if ((err = binary_buffer_next_u32(&buffer.bb, &value_count)))
return err;
if (!value_count)
goto not_found; /* Or is this malformed? */
/* Skip over priority. */
if ((err = binary_buffer_skip(&buffer.bb, 4)))
return err;
const char *colon = memchr(buffer.bb.pos, ':',
buffer.bb.end - buffer.bb.pos);
if (!colon) {
return binary_buffer_error(&buffer.bb,
"expected string containing ':'");
}
*path_ret = buffer.bb.pos;
*len_ret = colon - buffer.bb.pos;
return NULL;
not_found:
*path_ret = NULL;
return NULL;
}
/*
* Identify an ELF file as a kernel module, vmlinux, or neither. We classify a
* file as a kernel module if it has a section named .gnu.linkonce.this_module.
* If it doesn't, but it does have a section named .init.text, we classify it as
* vmlinux.
*/
static struct drgn_error *identify_kernel_elf(Elf *elf,
bool *is_vmlinux_ret,
bool *is_module_ret)
{
size_t shstrndx;
if (elf_getshdrstrndx(elf, &shstrndx))
return drgn_error_libelf();
Elf_Scn *scn = NULL;
bool have_init_text = false;
while ((scn = elf_nextscn(elf, scn))) {
GElf_Shdr *shdr, shdr_mem;
const char *scnname;
shdr = gelf_getshdr(scn, &shdr_mem);
if (!shdr)
continue;
scnname = elf_strptr(elf, shstrndx, shdr->sh_name);
if (!scnname)
return drgn_error_libelf();
if (strcmp(scnname, ".gnu.linkonce.this_module") == 0) {
*is_vmlinux_ret = false;
*is_module_ret = true;
return NULL;
} else if (strcmp(scnname, ".init.text") == 0) {
have_init_text = true;
}
}
*is_vmlinux_ret = have_init_text;
*is_module_ret = false;
return NULL;
}
DEFINE_HASH_MAP(elf_scn_name_map, const char *, Elf_Scn *,
c_string_key_hash_pair, c_string_key_eq);
static struct drgn_error *
cache_kernel_module_sections(struct kernel_module_iterator *kmod_it, Elf *elf)
{
struct drgn_error *err;
size_t shstrndx;
if (elf_getshdrstrndx(elf, &shstrndx))
return drgn_error_libelf();
struct elf_scn_name_map scn_map = HASH_TABLE_INIT;
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn(elf, scn))) {
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr(scn, &shdr_mem);
if (!shdr) {
err = drgn_error_libelf();
goto out_scn_map;
}
if (!(shdr->sh_flags & SHF_ALLOC))
continue;
struct elf_scn_name_map_entry entry = {
.key = elf_strptr(elf, shstrndx, shdr->sh_name),
.value = scn,
};
if (!entry.key) {
err = drgn_error_libelf();
goto out_scn_map;
}
if (elf_scn_name_map_insert(&scn_map, &entry, NULL) == -1) {
err = &drgn_enomem;
goto out_scn_map;
}
}
struct kernel_module_section_iterator section_it;
err = kernel_module_section_iterator_init(&section_it, kmod_it);
if (err)
goto out_scn_map;
const char *name;
uint64_t address;
while (!(err = kernel_module_section_iterator_next(&section_it, &name,
&address))) {
struct elf_scn_name_map_iterator it =
elf_scn_name_map_search(&scn_map, &name);
if (it.entry) {
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr(it.entry->value,
&shdr_mem);
if (!shdr) {
err = drgn_error_libelf();
break;
}
shdr->sh_addr = address;
if (!gelf_update_shdr(it.entry->value, shdr)) {
err = drgn_error_libelf();
break;
}
}
}
if (err && err != &drgn_stop)
goto out_section_it;
err = NULL;
out_section_it:
kernel_module_section_iterator_deinit(&section_it);
out_scn_map:
elf_scn_name_map_deinit(&scn_map);
return err;
}
struct kernel_module_file {
const char *path;
int fd;
Elf *elf;
/*
* Kernel module build ID. This is owned by the Elf handle. Because we
* use this as the key in the kernel_module_table, the file must always
* be removed from the table before it is reported to the DWARF index
* (which takes ownership of the Elf handle).
*/
const void *gnu_build_id;
size_t gnu_build_id_len;
/* Next file with the same build ID. */
struct kernel_module_file *next;
};
static struct nstring
kernel_module_table_key(struct kernel_module_file * const *entry)
{
return (struct nstring){
(*entry)->gnu_build_id, (*entry)->gnu_build_id_len
};
}
DEFINE_HASH_TABLE(kernel_module_table, struct kernel_module_file *,
kernel_module_table_key, nstring_hash_pair, nstring_eq);
static struct drgn_error *
report_loaded_kernel_module(struct drgn_debug_info_load_state *load,
struct kernel_module_iterator *kmod_it,
struct kernel_module_table *kmod_table)
{
struct drgn_error *err;
struct nstring key;
err = kernel_module_iterator_gnu_build_id(kmod_it,
(const void **)&key.str,
&key.len);
if (err || key.len == 0) {
return drgn_debug_info_report_error(load, kmod_it->name,
"could not find GNU build ID",
err);
}
struct hash_pair hp = kernel_module_table_hash(&key);
struct kernel_module_table_iterator it =
kernel_module_table_search_hashed(kmod_table, &key, hp);
if (!it.entry)
return &drgn_not_found;
struct kernel_module_file *kmod = *it.entry;
kernel_module_table_delete_iterator_hashed(kmod_table, it, hp);
do {
err = cache_kernel_module_sections(kmod_it, kmod->elf);
if (err) {
err = drgn_debug_info_report_error(load, kmod->path,
"could not get section addresses",
err);
if (err)
return err;
goto next;
}
err = drgn_debug_info_report_elf(load, kmod->path, kmod->fd,
kmod->elf, kmod_it->start,
kmod_it->end, kmod_it->name,
NULL);
kmod->elf = NULL;
kmod->fd = -1;
if (err)
return err;
next:
kmod = kmod->next;
} while (kmod);
return NULL;
}
static struct drgn_error *
report_default_kernel_module(struct drgn_debug_info_load_state *load,
struct kernel_module_iterator *kmod_it,
struct depmod_index *depmod)
{
static const char * const module_paths[] = {
"/usr/lib/debug/lib/modules/%s/%.*s",
"/usr/lib/debug/lib/modules/%s/%.*s.debug",
"/lib/modules/%s/%.*s%.*s",
NULL,
};
struct drgn_error *err;
const char *depmod_path;
size_t depmod_path_len;
err = depmod_index_find(depmod, kmod_it->name, &depmod_path,
&depmod_path_len);
if (err) {
return drgn_debug_info_report_error(load,
"kernel modules",
"could not parse depmod",
err);
} else if (!depmod_path) {
return drgn_debug_info_report_error(load, kmod_it->name,
"could not find module in depmod",
NULL);
}
size_t extension_len;
if (depmod_path_len >= 3 &&
(memcmp(depmod_path + depmod_path_len - 3, ".gz", 3) == 0 ||
memcmp(depmod_path + depmod_path_len - 3, ".xz", 3) == 0))
extension_len = 3;
else
extension_len = 0;
char *path;
int fd;
Elf *elf;
err = find_elf_file(&path, &fd, &elf, module_paths,
load->dbinfo->prog->vmcoreinfo.osrelease,
depmod_path_len - extension_len, depmod_path,
extension_len,
depmod_path + depmod_path_len - extension_len);
if (err)
return drgn_debug_info_report_error(load, NULL, NULL, err);
if (!elf) {
return drgn_debug_info_report_error(load, kmod_it->name,
"could not find .ko",
NULL);
}
err = cache_kernel_module_sections(kmod_it, elf);
if (err) {
err = drgn_debug_info_report_error(load, path,
"could not get section addresses",
err);
elf_end(elf);
close(fd);
free(path);
return err;
}
err = drgn_debug_info_report_elf(load, path, fd, elf, kmod_it->start,
kmod_it->end, kmod_it->name, NULL);
free(path);
return err;
}
static struct drgn_error *
report_loaded_kernel_modules(struct drgn_debug_info_load_state *load,
struct kernel_module_table *kmod_table,
struct depmod_index *depmod, bool use_sys_module)
{
struct drgn_program *prog = load->dbinfo->prog;
struct drgn_error *err;
struct kernel_module_iterator kmod_it;
err = kernel_module_iterator_init(&kmod_it, prog, use_sys_module);
if (err) {
kernel_module_iterator_error:
return drgn_debug_info_report_error(load, "kernel modules",
"could not find loaded kernel modules",
err);
}
for (;;) {
err = kernel_module_iterator_next(&kmod_it);
if (err == &drgn_stop) {
err = NULL;
break;
} else if (err) {
kernel_module_iterator_deinit(&kmod_it);
goto kernel_module_iterator_error;
}
/* Look for an explicitly-reported file first. */
if (kmod_table) {
err = report_loaded_kernel_module(load, &kmod_it,
kmod_table);
if (!err)
continue;
else if (err != &drgn_not_found)
break;
}
/*
* If it was not reported explicitly and we're also reporting the
* defaults, look for the module at the standard locations unless we've
* already indexed that module.
*/
if (depmod &&
!drgn_debug_info_is_indexed(load->dbinfo, kmod_it.name)) {
if (!depmod->addr) {
err = depmod_index_init(depmod,
prog->vmcoreinfo.osrelease);
if (err) {
depmod->addr = NULL;
err = drgn_debug_info_report_error(load,
"kernel modules",
"could not read depmod",
err);
if (err)
break;
depmod = NULL;
continue;
}
}
err = report_default_kernel_module(load, &kmod_it,
depmod);
if (err)
break;
}
}
kernel_module_iterator_deinit(&kmod_it);
return err;
}
static struct drgn_error *
report_kernel_modules(struct drgn_debug_info_load_state *load,
struct kernel_module_file *kmods, size_t num_kmods,
bool vmlinux_is_pending)
{
struct drgn_program *prog = load->dbinfo->prog;
struct drgn_error *err;
if (!num_kmods && !load->load_default)
return NULL;
/*
* If we're debugging the running kernel, we can use
* /sys/module/$module/notes and /sys/module/$module/sections instead of
* getting the equivalent information from the core dump. This fast path
* can be disabled via an environment variable for testing.
*/
bool use_sys_module = false;
if (prog->flags & DRGN_PROGRAM_IS_LIVE) {
char *env = getenv("DRGN_USE_SYS_MODULE");
use_sys_module = !env || atoi(env);
}
/*
* We need to index vmlinux now so that we can walk the list of modules
* in the kernel.
*/
if (vmlinux_is_pending) {
err = drgn_debug_info_report_flush(load);
if (err)
return err;
}
struct kernel_module_table kmod_table = HASH_TABLE_INIT;
struct depmod_index depmod;
depmod.addr = NULL;
struct kernel_module_table_iterator it;
for (size_t i = 0; i < num_kmods; i++) {
struct kernel_module_file *kmod = &kmods[i];
ssize_t build_id_len =
dwelf_elf_gnu_build_id(kmod->elf, &kmod->gnu_build_id);
if (build_id_len < 0) {
err = drgn_debug_info_report_error(load, kmod->path,
NULL,
drgn_error_libelf());
if (err)
goto out;
continue;
}
kmod->gnu_build_id_len = build_id_len;
struct nstring key = kernel_module_table_key(&kmod);
struct hash_pair hp = kernel_module_table_hash(&key);
it = kernel_module_table_search_hashed(&kmod_table, &key, hp);
if (it.entry) {
kmod->next = *it.entry;
*it.entry = kmod;
} else {
if (kernel_module_table_insert_searched(&kmod_table,
&kmod, hp,
NULL) == -1) {
err = &drgn_enomem;
goto out;
}
kmod->next = NULL;
}
}
err = report_loaded_kernel_modules(load, num_kmods ? &kmod_table : NULL,
load->load_default ? &depmod : NULL,
use_sys_module);
if (err)
goto out;
/* Anything left over was not loaded. */
for (it = kernel_module_table_first(&kmod_table); it.entry; ) {
struct kernel_module_file *kmod = *it.entry;
it = kernel_module_table_delete_iterator(&kmod_table, it);
do {
err = drgn_debug_info_report_elf(load, kmod->path,
kmod->fd, kmod->elf, 0,
0, kmod->path, NULL);
kmod->elf = NULL;
kmod->fd = -1;
if (err)
goto out;
kmod = kmod->next;
} while (kmod);
}
err = NULL;
out:
if (depmod.addr)
depmod_index_deinit(&depmod);
kernel_module_table_deinit(&kmod_table);
return err;
}
static struct drgn_error *
report_vmlinux(struct drgn_debug_info_load_state *load,
bool *vmlinux_is_pending)
{
static const char * const vmlinux_paths[] = {
/*
* The files under /usr/lib/debug should always have debug
* information, so check for those first.
*/
"/usr/lib/debug/boot/vmlinux-%s",
"/usr/lib/debug/lib/modules/%s/vmlinux",
"/boot/vmlinux-%s",
"/lib/modules/%s/build/vmlinux",
"/lib/modules/%s/vmlinux",
NULL,
};
struct drgn_program *prog = load->dbinfo->prog;
struct drgn_error *err;
char *path;
int fd;
Elf *elf;
err = find_elf_file(&path, &fd, &elf, vmlinux_paths,
prog->vmcoreinfo.osrelease);
if (err)
return drgn_debug_info_report_error(load, NULL, NULL, err);
if (!elf) {
err = drgn_error_format(DRGN_ERROR_OTHER,
"could not find vmlinux for %s",
prog->vmcoreinfo.osrelease);
return drgn_debug_info_report_error(load, "kernel", NULL, err);
}
uint64_t start, end;
err = elf_address_range(elf, prog->vmcoreinfo.kaslr_offset, &start,
&end);
if (err) {
err = drgn_debug_info_report_error(load, path, NULL, err);
elf_end(elf);
close(fd);
free(path);
return err;
}
err = drgn_debug_info_report_elf(load, path, fd, elf, start, end,
"kernel", vmlinux_is_pending);
free(path);
return err;
}
struct drgn_error *
linux_kernel_report_debug_info(struct drgn_debug_info_load_state *load)
{
struct drgn_program *prog = load->dbinfo->prog;
struct drgn_error *err;
struct kernel_module_file *kmods;
if (load->num_paths) {
kmods = malloc_array(load->num_paths, sizeof(*kmods));
if (!kmods)
return &drgn_enomem;
} else {
kmods = NULL;
}
/*
* We may need to index vmlinux before we can properly report kernel
* modules. So, this sets aside kernel modules and reports everything
* else.
*/
size_t num_kmods = 0;
bool vmlinux_is_pending = false;
for (size_t i = 0; i < load->num_paths; i++) {
const char *path = load->paths[i];
int fd;
Elf *elf;
err = open_elf_file(path, &fd, &elf);
if (err) {
err = drgn_debug_info_report_error(load, path, NULL,
err);
if (err)
goto out;
continue;
}
bool is_vmlinux, is_module;
err = identify_kernel_elf(elf, &is_vmlinux, &is_module);
if (err) {
err = drgn_debug_info_report_error(load, path, NULL,
err);
elf_end(elf);
close(fd);
if (err)
goto out;
continue;
}
if (is_module) {
struct kernel_module_file *kmod = &kmods[num_kmods++];
kmod->path = path;
kmod->fd = fd;
kmod->elf = elf;
} else if (is_vmlinux) {
uint64_t start, end;
err = elf_address_range(elf,
prog->vmcoreinfo.kaslr_offset,
&start, &end);
if (err) {
elf_end(elf);
close(fd);
err = drgn_debug_info_report_error(load, path,
NULL, err);
if (err)
goto out;
continue;
}
bool is_new;
err = drgn_debug_info_report_elf(load, path, fd, elf,
start, end, "kernel",
&is_new);
if (err)
goto out;
if (is_new)
vmlinux_is_pending = true;
} else {
err = drgn_debug_info_report_elf(load, path, fd, elf, 0,
0, NULL, NULL);
if (err)
goto out;
}
}
if (load->load_main && !vmlinux_is_pending &&
!drgn_debug_info_is_indexed(load->dbinfo, "kernel")) {
err = report_vmlinux(load, &vmlinux_is_pending);
if (err)
goto out;
}
err = report_kernel_modules(load, kmods, num_kmods, vmlinux_is_pending);
out:
for (size_t i = 0; i < num_kmods; i++) {
elf_end(kmods[i].elf);
if (kmods[i].fd != -1)
close(kmods[i].fd);
}
free(kmods);
return err;
}
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