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program.c
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// Copyright (c) Meta Platforms, Inc. and affiliates.
// SPDX-License-Identifier: LGPL-2.1-or-later
#include <assert.h>
#include <byteswap.h>
#include <dirent.h>
#include <elf.h>
#include <elfutils/libdw.h>
#include <errno.h>
#include <fcntl.h>
#include <gelf.h>
#include <inttypes.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/statfs.h>
#include <sys/types.h>
#include <unistd.h>
#include "cleanup.h"
#include "debug_info.h"
#include "elf_notes.h"
#include "error.h"
#include "helpers.h"
#include "io.h"
#include "language.h"
#include "log.h"
#include "linux_kernel.h"
#include "log.h"
#include "memory_reader.h"
#include "minmax.h"
#include "object.h"
#include "program.h"
#include "serialize.h"
#include "symbol.h"
#include "util.h"
#include "vector.h"
static inline uint32_t drgn_thread_to_key(const struct drgn_thread *entry)
{
return entry->tid;
}
DEFINE_HASH_TABLE_FUNCTIONS(drgn_thread_set, drgn_thread_to_key,
int_key_hash_pair, scalar_key_eq);
struct drgn_thread_iterator {
struct drgn_program *prog;
union {
/* For userspace core dumps. */
struct drgn_thread_set_iterator iterator;
struct {
union {
/* For live processes. */
DIR *tasks_dir;
/* For the Linux kernel. */
struct linux_helper_task_iterator task_iter;
};
/* For both live processes and the Linux kernel. */
struct drgn_thread entry;
};
};
};
LIBDRGN_PUBLIC enum drgn_program_flags
drgn_program_flags(struct drgn_program *prog)
{
return prog->flags;
}
LIBDRGN_PUBLIC const struct drgn_platform *
drgn_program_platform(struct drgn_program *prog)
{
return prog->has_platform ? &prog->platform : NULL;
}
LIBDRGN_PUBLIC const struct drgn_language *
drgn_program_language(struct drgn_program *prog)
{
if (prog->lang)
return prog->lang;
if (prog->flags & DRGN_PROGRAM_IS_LINUX_KERNEL) {
prog->lang = &drgn_language_c;
return prog->lang;
}
if (!prog->tried_main_language) {
prog->tried_main_language = true;
prog->lang = drgn_debug_info_main_language(&prog->dbinfo);
if (prog->lang) {
drgn_log_debug(prog,
"set default language to %s from main()",
prog->lang->name);
return prog->lang;
} else {
drgn_log_debug(prog,
"couldn't find language of main(); defaulting to %s",
drgn_default_language.name);
}
}
return &drgn_default_language;
}
LIBDRGN_PUBLIC void drgn_program_set_language(struct drgn_program *prog,
const struct drgn_language *lang)
{
prog->lang = lang;
}
void drgn_program_set_platform(struct drgn_program *prog,
const struct drgn_platform *platform)
{
if (!prog->has_platform) {
prog->platform = *platform;
prog->has_platform = true;
}
}
void drgn_program_init(struct drgn_program *prog,
const struct drgn_platform *platform)
{
memset(prog, 0, sizeof(*prog));
drgn_memory_reader_init(&prog->reader);
drgn_program_init_types(prog);
drgn_debug_info_init(&prog->dbinfo, prog);
prog->core_fd = -1;
if (platform)
drgn_program_set_platform(prog, platform);
drgn_thread_set_init(&prog->thread_set);
drgn_program_set_log_level(prog, DRGN_LOG_NONE);
drgn_program_set_log_file(prog, stderr);
prog->default_progress_file = true;
drgn_object_init(&prog->vmemmap, prog);
}
void drgn_program_deinit(struct drgn_program *prog)
{
drgn_thread_set_deinit(&prog->thread_set);
/*
* For userspace core dumps, main_thread and crashed_thread are in
* prog->thread_set and thus freed by the above call to
* drgn_thread_set_deinit().
*/
if (!drgn_program_is_userspace_core(prog)) {
drgn_thread_destroy(prog->crashed_thread);
drgn_thread_destroy(prog->main_thread);
}
if (prog->pgtable_it)
prog->platform.arch->linux_kernel_pgtable_iterator_destroy(prog->pgtable_it);
drgn_object_deinit(&prog->vmemmap);
drgn_handler_list_deinit(struct drgn_symbol_finder, finder,
&prog->symbol_finders,
if (finder->ops.destroy)
finder->ops.destroy(finder->arg);
);
drgn_handler_list_deinit(struct drgn_object_finder, finder,
&prog->object_finders,
if (finder->ops.destroy)
finder->ops.destroy(finder->arg);
);
drgn_program_deinit_types(prog);
drgn_memory_reader_deinit(&prog->reader);
free(prog->file_segments);
free(prog->vmcoreinfo.raw);
#ifdef WITH_LIBKDUMPFILE
if (prog->kdump_ctx)
kdump_free(prog->kdump_ctx);
#endif
elf_end(prog->core);
if (prog->core_fd != -1)
close(prog->core_fd);
drgn_debug_info_deinit(&prog->dbinfo);
}
LIBDRGN_PUBLIC struct drgn_error *
drgn_program_create(const struct drgn_platform *platform,
struct drgn_program **ret)
{
struct drgn_program *prog;
prog = malloc(sizeof(*prog));
if (!prog)
return &drgn_enomem;
drgn_program_init(prog, platform);
*ret = prog;
return NULL;
}
LIBDRGN_PUBLIC void drgn_program_destroy(struct drgn_program *prog)
{
if (prog) {
drgn_program_deinit(prog);
free(prog);
}
}
LIBDRGN_PUBLIC struct drgn_error *
drgn_program_add_memory_segment(struct drgn_program *prog, uint64_t address,
uint64_t size, drgn_memory_read_fn read_fn,
void *arg, bool physical)
{
uint64_t address_mask;
struct drgn_error *err = drgn_program_address_mask(prog, &address_mask);
if (err)
return err;
if (size == 0 || address > address_mask)
return NULL;
uint64_t max_address = address + min(size - 1, address_mask - address);
return drgn_memory_reader_add_segment(&prog->reader, address,
max_address, read_fn, arg,
physical);
}
#define DRGN_PROGRAM_FINDER(which) \
struct drgn_error * \
drgn_program_register_##which##_finder_impl(struct drgn_program *prog, \
struct drgn_##which##_finder *finder,\
const char *name, \
const struct drgn_##which##_finder_ops *ops,\
void *arg, size_t enable_index) \
{ \
struct drgn_error *err; \
if (finder) { \
finder->handler.name = name; \
finder->handler.free = false; \
} else { \
finder = malloc(sizeof(*finder)); \
if (!finder) \
return &drgn_enomem; \
finder->handler.name = strdup(name); \
if (!finder->handler.name) { \
free(finder); \
return &drgn_enomem; \
} \
finder->handler.free = true; \
} \
memcpy(&finder->ops, ops, sizeof(finder->ops)); \
finder->arg = arg; \
err = drgn_handler_list_register(&prog->which##_finders, \
&finder->handler, enable_index, \
#which " finder"); \
if (err && finder->handler.free) { \
free((char *)finder->handler.name); \
free(finder); \
} \
return err; \
} \
\
LIBDRGN_PUBLIC struct drgn_error * \
drgn_program_register_##which##_finder(struct drgn_program *prog, const char *name,\
const struct drgn_##which##_finder_ops *ops,\
void *arg, size_t enable_index) \
{ \
return drgn_program_register_##which##_finder_impl(prog, NULL, name, \
ops, arg, \
enable_index); \
} \
\
LIBDRGN_PUBLIC struct drgn_error * \
drgn_program_registered_##which##_finders(struct drgn_program *prog, \
const char ***names_ret, \
size_t *count_ret) \
{ \
return drgn_handler_list_registered(&prog->which##_finders, names_ret, \
count_ret); \
} \
\
LIBDRGN_PUBLIC struct drgn_error * \
drgn_program_set_enabled_##which##_finders(struct drgn_program *prog, \
const char * const *names, \
size_t count) \
{ \
return drgn_handler_list_set_enabled(&prog->which##_finders, names, \
count, #which "finder"); \
} \
\
LIBDRGN_PUBLIC struct drgn_error * \
drgn_program_enabled_##which##_finders(struct drgn_program *prog, \
const char ***names_ret, \
size_t *count_ret) \
{ \
return drgn_handler_list_enabled(&prog->which##_finders, names_ret, \
count_ret); \
}
DRGN_PROGRAM_FINDER(type)
DRGN_PROGRAM_FINDER(object)
DRGN_PROGRAM_FINDER(symbol)
#undef DRGN_PROGRAM_FINDER
static struct drgn_error *
drgn_program_check_initialized(struct drgn_program *prog)
{
if (prog->core_fd != -1 || !drgn_memory_reader_empty(&prog->reader)) {
return drgn_error_create(DRGN_ERROR_INVALID_ARGUMENT,
"program memory was already initialized");
}
return NULL;
}
static struct drgn_error *
has_kdump_signature(struct drgn_program *prog, const char *path, bool *ret)
{
char signature[max_iconst(KDUMP_SIG_LEN, FLATTENED_SIG_LEN)];
ssize_t r = pread_all(prog->core_fd, signature, sizeof(signature), 0);
if (r < 0)
return drgn_error_create_os("pread", errno, path);
*ret = false;
if (r >= FLATTENED_SIG_LEN
&& memcmp(signature, FLATTENED_SIGNATURE, FLATTENED_SIG_LEN) == 0) {
drgn_log_warning(prog,
"the given file is in the makedumpfile flattened "
"format; if open fails or is too slow, reassemble "
"it with 'makedumpfile -R newfile <oldfile'");
*ret = true;
} else if (r >= KDUMP_SIG_LEN
&& memcmp(signature, KDUMP_SIGNATURE, KDUMP_SIG_LEN) == 0)
*ret = true;
return NULL;
}
static struct drgn_error *
drgn_program_set_core_dump_fd_internal(struct drgn_program *prog, int fd,
const char *path)
{
struct drgn_error *err;
GElf_Ehdr ehdr_mem, *ehdr;
bool had_platform;
bool is_64_bit, little_endian, is_kdump;
size_t phnum, i;
size_t num_file_segments, j;
bool have_phys_addrs = false;
bool have_qemu_note = false;
const char *vmcoreinfo_note = NULL;
size_t vmcoreinfo_size = 0;
bool have_nt_taskstruct = false, is_proc_kcore;
bool have_vmcoreinfo = prog->vmcoreinfo.raw;
bool had_vmcoreinfo = have_vmcoreinfo;
prog->core_fd = fd;
err = has_kdump_signature(prog, path, &is_kdump);
if (err)
goto out_fd;
if (is_kdump) {
err = drgn_program_set_kdump(prog);
if (err)
goto out_fd;
return NULL;
}
elf_version(EV_CURRENT);
prog->core = elf_begin(prog->core_fd, ELF_C_READ, NULL);
if (!prog->core) {
err = drgn_error_libelf();
goto out_fd;
}
ehdr = gelf_getehdr(prog->core, &ehdr_mem);
if (!ehdr || ehdr->e_type != ET_CORE) {
err = drgn_error_format(DRGN_ERROR_INVALID_ARGUMENT,
"not an ELF core file");
goto out_elf;
}
had_platform = prog->has_platform;
if (!had_platform) {
struct drgn_platform platform;
drgn_platform_from_elf(ehdr, &platform);
drgn_program_set_platform(prog, &platform);
}
is_64_bit = ehdr->e_ident[EI_CLASS] == ELFCLASS64;
little_endian = ehdr->e_ident[EI_DATA] == ELFDATA2LSB;
if (elf_getphdrnum(prog->core, &phnum) != 0) {
err = drgn_error_libelf();
goto out_platform;
}
/*
* First pass: count the number of loadable segments, check if p_paddr
* is valid, and check for notes.
*/
num_file_segments = 0;
for (i = 0; i < phnum; i++) {
GElf_Phdr phdr_mem, *phdr;
phdr = gelf_getphdr(prog->core, i, &phdr_mem);
if (!phdr) {
err = drgn_error_libelf();
goto out_notes;
}
if (phdr->p_type == PT_LOAD) {
if (phdr->p_paddr)
have_phys_addrs = true;
num_file_segments++;
} else if (phdr->p_type == PT_NOTE) {
Elf_Data *data;
size_t offset;
GElf_Nhdr nhdr;
size_t name_offset, desc_offset;
data = elf_getdata_rawchunk(prog->core, phdr->p_offset,
phdr->p_filesz,
note_header_type(phdr->p_align));
if (!data) {
err = drgn_error_libelf();
goto out_notes;
}
offset = 0;
while (offset < data->d_size &&
(offset = gelf_getnote(data, offset, &nhdr,
&name_offset,
&desc_offset))) {
const char *name, *desc;
name = (char *)data->d_buf + name_offset;
desc = (char *)data->d_buf + desc_offset;
if (nhdr.n_namesz == sizeof("CORE") &&
memcmp(name, "CORE", sizeof("CORE")) == 0) {
if (nhdr.n_type == NT_TASKSTRUCT)
have_nt_taskstruct = true;
} else if (nhdr.n_namesz == sizeof("LINUX") &&
memcmp(name, "LINUX",
sizeof("LINUX")) == 0) {
if (nhdr.n_type == NT_ARM_PAC_MASK &&
nhdr.n_descsz >=
2 * sizeof(uint64_t)) {
memcpy(&prog->aarch64_insn_pac_mask,
(uint64_t *)desc + 1,
sizeof(uint64_t));
if (little_endian !=
HOST_LITTLE_ENDIAN)
bswap_64(prog->aarch64_insn_pac_mask);
}
} else if (nhdr.n_namesz == sizeof("VMCOREINFO") &&
memcmp(name, "VMCOREINFO",
sizeof("VMCOREINFO")) == 0) {
vmcoreinfo_note = desc;
vmcoreinfo_size = nhdr.n_descsz;
/*
* This is either a vmcore or
* /proc/kcore, so even a p_paddr of 0
* may be valid.
*/
have_phys_addrs = true;
have_vmcoreinfo = true;
} else if (nhdr.n_namesz == sizeof("QEMU") &&
memcmp(name, "QEMU",
sizeof("QEMU")) == 0) {
have_qemu_note = true;
}
}
}
}
if (have_nt_taskstruct) {
/*
* If the core file has an NT_TASKSTRUCT note and is in /proc,
* then it's probably /proc/kcore.
*/
struct statfs fs;
if (fstatfs(prog->core_fd, &fs) == -1) {
err = drgn_error_create_os("fstatfs", errno, path);
if (err)
goto out_notes;
}
is_proc_kcore = fs.f_type == 0x9fa0; /* PROC_SUPER_MAGIC */
} else {
is_proc_kcore = false;
}
if (have_vmcoreinfo && !is_proc_kcore) {
char *env;
/* Use libkdumpfile for ELF vmcores if it was requested. */
env = getenv("DRGN_USE_LIBKDUMPFILE_FOR_ELF");
if (env && atoi(env)) {
err = drgn_program_set_kdump(prog);
if (err)
goto out_notes;
return NULL;
}
}
prog->file_segments = malloc_array(num_file_segments,
sizeof(*prog->file_segments));
if (!prog->file_segments) {
err = &drgn_enomem;
goto out_notes;
}
bool pgtable_reader =
(is_proc_kcore || have_vmcoreinfo) &&
prog->platform.arch->linux_kernel_pgtable_iterator_next;
if (pgtable_reader) {
/*
* Try to read any memory that isn't in the core dump via the
* page table.
*/
err = drgn_program_add_memory_segment(prog, 0, UINT64_MAX,
read_memory_via_pgtable,
prog, false);
if (err)
goto out_segments;
}
/* Second pass: add the segments. */
for (i = 0, j = 0; i < phnum && j < num_file_segments; i++) {
GElf_Phdr phdr_mem, *phdr;
phdr = gelf_getphdr(prog->core, i, &phdr_mem);
if (!phdr) {
err = drgn_error_libelf();
goto out_segments;
}
if (phdr->p_type != PT_LOAD)
continue;
prog->file_segments[j].file_offset = phdr->p_offset;
prog->file_segments[j].file_size = phdr->p_filesz;
prog->file_segments[j].fd = prog->core_fd;
prog->file_segments[j].eio_is_fault = false;
/*
* p_filesz < p_memsz is ambiguous for core dumps. The ELF
* specification says that "if the segment's memory size p_memsz
* is larger than the file size p_filesz, the 'extra' bytes are
* defined to hold the value 0 and to follow the segment's
* initialized area."
*
* However, the Linux kernel generates userspace core dumps with
* segments with p_filesz < p_memsz to indicate that the range
* between p_filesz and p_memsz was filtered out (see
* coredump_filter in core(5)). These bytes were not necessarily
* zeroes in the process's memory, which contradicts the ELF
* specification in a way.
*
* As of Linux 5.19, /proc/kcore and /proc/vmcore never have
* segments with p_filesz < p_memsz. However, makedumpfile
* creates segments with p_filesz < p_memsz to indicate ranges
* that were excluded. This is similar to Linux userspace core
* dumps, except that makedumpfile can also exclude ranges that
* were all zeroes.
*
* So, for userspace core dumps, we want to fault for ranges
* between p_filesz and p_memsz to indicate that the memory was
* not saved rather than lying and returning zeroes. For
* /proc/kcore, we don't expect to see p_filesz < p_memsz but we
* fault to be safe. For Linux kernel core dumps, we can't
* distinguish between memory that was excluded because it was
* all zeroes and memory that was excluded by makedumpfile for
* another reason, so we're forced to always return zeroes.
*/
prog->file_segments[j].zerofill = have_vmcoreinfo && !is_proc_kcore;
err = drgn_program_add_memory_segment(prog, phdr->p_vaddr,
phdr->p_memsz,
drgn_read_memory_file,
&prog->file_segments[j],
false);
if (err)
goto out_segments;
if (have_phys_addrs &&
phdr->p_paddr != (is_64_bit ? UINT64_MAX : UINT32_MAX)) {
err = drgn_program_add_memory_segment(prog,
phdr->p_paddr,
phdr->p_memsz,
drgn_read_memory_file,
&prog->file_segments[j],
true);
if (err)
goto out_segments;
}
j++;
}
/*
* Before Linux kernel commit 464920104bf7 ("/proc/kcore: update
* physical address for kcore ram and text") (in v4.11), p_paddr in
* /proc/kcore is always zero. If we know the address of the direct
* mapping, we can still add physical segments. This needs to be a third
* pass, as we may need to read virtual memory to determine the mapping.
*/
if (is_proc_kcore && !have_phys_addrs &&
prog->platform.arch->linux_kernel_live_direct_mapping_fallback) {
uint64_t direct_mapping, direct_mapping_size;
err = prog->platform.arch->linux_kernel_live_direct_mapping_fallback(prog,
&direct_mapping,
&direct_mapping_size);
if (err)
goto out_segments;
for (i = 0, j = 0; i < phnum && j < num_file_segments; i++) {
GElf_Phdr phdr_mem, *phdr;
phdr = gelf_getphdr(prog->core, i, &phdr_mem);
if (!phdr) {
err = drgn_error_libelf();
goto out_segments;
}
if (phdr->p_type != PT_LOAD)
continue;
if (phdr->p_vaddr >= direct_mapping &&
phdr->p_vaddr - direct_mapping + phdr->p_memsz <=
direct_mapping_size) {
uint64_t phys_addr;
phys_addr = phdr->p_vaddr - direct_mapping;
err = drgn_program_add_memory_segment(prog,
phys_addr,
pgtable_reader ?
phdr->p_filesz :
phdr->p_memsz,
drgn_read_memory_file,
&prog->file_segments[j],
true);
if (err)
goto out_segments;
}
j++;
}
}
if (vmcoreinfo_note && !prog->vmcoreinfo.raw) {
err = drgn_program_parse_vmcoreinfo(prog, vmcoreinfo_note,
vmcoreinfo_size);
if (err)
goto out_segments;
}
if (is_proc_kcore) {
if (!have_vmcoreinfo) {
err = read_vmcoreinfo_fallback(prog);
if (err)
goto out_segments;
}
prog->flags |= (DRGN_PROGRAM_IS_LINUX_KERNEL |
DRGN_PROGRAM_IS_LIVE |
DRGN_PROGRAM_IS_LOCAL);
elf_end(prog->core);
prog->core = NULL;
} else if (have_vmcoreinfo) {
prog->flags |= DRGN_PROGRAM_IS_LINUX_KERNEL;
} else if (have_qemu_note) {
err = drgn_error_create(DRGN_ERROR_INVALID_ARGUMENT,
"unrecognized QEMU memory dump; "
"for Linux guests, run QEMU with '-device vmcoreinfo', "
"compile the kernel with CONFIG_FW_CFG_SYSFS and CONFIG_KEXEC, "
"and load the qemu_fw_cfg kernel module "
"before dumping the guest memory "
"(requires Linux >= 4.17 and QEMU >= 2.11)");
goto out_segments;
}
if (prog->flags & DRGN_PROGRAM_IS_LINUX_KERNEL) {
err = drgn_program_finish_set_kernel(prog);
if (err)
goto out_segments;
}
return NULL;
out_segments:
drgn_memory_reader_deinit(&prog->reader);
drgn_memory_reader_init(&prog->reader);
free(prog->file_segments);
prog->file_segments = NULL;
out_notes:
// Reset anything we parsed from ELF notes.
prog->aarch64_insn_pac_mask = 0;
// Free vmcoreinfo buffer if it was not provided by the caller
if (!had_vmcoreinfo) {
free(prog->vmcoreinfo.raw);
memset(&prog->vmcoreinfo, 0, sizeof(prog->vmcoreinfo));
}
out_platform:
prog->has_platform = had_platform;
out_elf:
elf_end(prog->core);
prog->core = NULL;
out_fd:
close(prog->core_fd);
prog->core_fd = -1;
return err;
}
LIBDRGN_PUBLIC struct drgn_error *
drgn_program_set_core_dump_fd(struct drgn_program *prog, int fd)
{
struct drgn_error *err;
err = drgn_program_check_initialized(prog);
if (err)
return err;
#define FORMAT "/proc/self/fd/%d"
char path[sizeof(FORMAT) - sizeof("%d") + max_decimal_length(int) + 1];
snprintf(path, sizeof(path), FORMAT, fd);
#undef FORMAT
return drgn_program_set_core_dump_fd_internal(prog, fd, path);
}
LIBDRGN_PUBLIC struct drgn_error *
drgn_program_set_core_dump(struct drgn_program *prog, const char *path)
{
struct drgn_error *err;
err = drgn_program_check_initialized(prog);
if (err)
return err;
int fd = open(path, O_RDONLY);
if (fd == -1)
return drgn_error_create_os("open", errno, path);
return drgn_program_set_core_dump_fd_internal(prog, fd, path);
}
LIBDRGN_PUBLIC struct drgn_error *
drgn_program_set_kernel(struct drgn_program *prog)
{
return drgn_program_set_core_dump(prog, "/proc/kcore");
}
LIBDRGN_PUBLIC struct drgn_error *
drgn_program_set_pid(struct drgn_program *prog, pid_t pid)
{
struct drgn_error *err;
err = drgn_program_check_initialized(prog);
if (err)
return err;
#define FORMAT "/proc/%ld/mem"
char buf[sizeof(FORMAT) - sizeof("%ld") + max_decimal_length(long) + 1];
snprintf(buf, sizeof(buf), FORMAT, (long)pid);
#undef FORMAT
prog->core_fd = open(buf, O_RDONLY);
if (prog->core_fd == -1)
return drgn_error_create_os("open", errno, buf);
bool had_platform = prog->has_platform;
drgn_program_set_platform(prog, &drgn_host_platform);
prog->file_segments = malloc(sizeof(*prog->file_segments));
if (!prog->file_segments) {
err = &drgn_enomem;
goto out_fd;
}
prog->file_segments[0].file_offset = 0;
prog->file_segments[0].file_size = UINT64_MAX;
prog->file_segments[0].fd = prog->core_fd;
prog->file_segments[0].eio_is_fault = true;
prog->file_segments[0].zerofill = false;
err = drgn_program_add_memory_segment(prog, 0, UINT64_MAX,
drgn_read_memory_file,
prog->file_segments, false);
if (err)
goto out_segments;
prog->pid = pid;
prog->flags |= DRGN_PROGRAM_IS_LIVE | DRGN_PROGRAM_IS_LOCAL;
return NULL;
out_segments:
drgn_memory_reader_deinit(&prog->reader);
drgn_memory_reader_init(&prog->reader);
free(prog->file_segments);
prog->file_segments = NULL;
out_fd:
prog->has_platform = had_platform;
close(prog->core_fd);
prog->core_fd = -1;
return err;
}
struct drgn_error *drgn_program_cache_auxv(struct drgn_program *prog)
{
if (prog->auxv_cached)
return NULL;
_cleanup_close_ int fd = -1;
const void *note;
size_t note_size;
#define FORMAT "/proc/%ld/auxv"
char path[sizeof(FORMAT)
- sizeof("%ld")
+ max_decimal_length(long)
+ 1];
if (drgn_program_is_userspace_process(prog)) {
snprintf(path, sizeof(path), FORMAT, (long)prog->pid);
#undef FORMAT
fd = open(path, O_RDONLY);
if (fd < 0)
return drgn_error_create_os("open", errno, path);
drgn_log_debug(prog, "parsing %s", path);
} else {
assert(drgn_program_is_userspace_core(prog));
if (find_elf_note(prog->core, "CORE", NT_AUXV, ¬e,
¬e_size))
return drgn_error_libelf();
if (!note) {
return drgn_error_create(DRGN_ERROR_OTHER,
"core file is missing NT_AUXV");
}
drgn_log_debug(prog, "parsing NT_AUXV");
}
memset(&prog->auxv, 0, sizeof(prog->auxv));
bool is_64_bit = drgn_platform_is_64_bit(&prog->platform);
bool bswap = drgn_platform_bswap(&prog->platform);
size_t aux_size = is_64_bit ? 16 : 8;
#define visit_aux_members(visit_scalar_member, visit_raw_member) do { \
visit_scalar_member(a_type); \
visit_scalar_member(a_un.a_val); \
} while (0)
for (;;) {
Elf64_auxv_t auxv;
if (fd >= 0) {
ssize_t r = read_all(fd, &auxv, aux_size);
if (r < 0)
return drgn_error_create_os("read", errno, path);
if (r < aux_size)
break;
deserialize_struct64_inplace(&auxv, Elf32_auxv_t,
visit_aux_members,
is_64_bit, bswap);
} else {
if (note_size < aux_size)
break;
deserialize_struct64(&auxv, Elf32_auxv_t,
visit_aux_members, note, is_64_bit,
bswap);
note = (char *)note + aux_size;
note_size -= aux_size;
}
if (auxv.a_type == 0 && auxv.a_un.a_val == 0)
break;
switch (auxv.a_type) {
case AT_PHDR:
drgn_log_debug(prog, "found AT_PHDR 0x%" PRIx64,
auxv.a_un.a_val);
prog->auxv.at_phdr = auxv.a_un.a_val;
break;
case AT_PHNUM:
drgn_log_debug(prog, "found AT_PHNUM %" PRIu64,
auxv.a_un.a_val);
prog->auxv.at_phnum = auxv.a_un.a_val;
break;
case AT_SYSINFO_EHDR:
drgn_log_debug(prog, "found AT_SYSINFO_EHDR 0x%" PRIx64,
auxv.a_un.a_val);
prog->auxv.at_sysinfo_ehdr = auxv.a_un.a_val;
break;
}
}
#undef visit_aux_members
prog->auxv_cached = true;
return NULL;
}
static struct drgn_error *get_prstatus_pid(struct drgn_program *prog, const char *data,
size_t size, uint32_t *ret)
{
bool is_64_bit, bswap;
struct drgn_error *err = drgn_program_is_64_bit(prog, &is_64_bit);
if (err)
return err;
err = drgn_program_bswap(prog, &bswap);
if (err)
return err;
size_t offset = is_64_bit ? 32 : 24;
uint32_t pr_pid;
if (size < offset + sizeof(pr_pid)) {
return drgn_error_create(DRGN_ERROR_OTHER,
"NT_PRSTATUS is truncated");
}
memcpy(&pr_pid, data + offset, sizeof(pr_pid));
if (bswap)
pr_pid = bswap_32(pr_pid);
*ret = pr_pid;
return NULL;
}
static struct drgn_error *get_prpsinfo_pid(struct drgn_program *prog,
const char *data, size_t size,
uint32_t *ret)
{
bool is_64_bit, bswap;
struct drgn_error *err = drgn_program_is_64_bit(prog, &is_64_bit);
if (err)
return err;
err = drgn_program_bswap(prog, &bswap);
if (err)
return err;
size_t offset = is_64_bit ? 24 : 12;
uint32_t pr_pid;
if (size < offset + sizeof(pr_pid)) {
return drgn_error_create(DRGN_ERROR_OTHER,
"NT_PRPSINFO is truncated");
}
memcpy(&pr_pid, data + offset, sizeof(pr_pid));
if (bswap)
pr_pid = bswap_32(pr_pid);
*ret = pr_pid;
return NULL;
}
static struct drgn_error *get_prpsinfo_fname(struct drgn_program *prog,
const char *data, size_t size,
const char **ret)
{
bool is_64_bit;
struct drgn_error *err = drgn_program_is_64_bit(prog, &is_64_bit);
if (err)
return err;
size_t offset = is_64_bit ? 40 : 28;
// pr_fname is defined as 16 byte buffer in elf_prpsinfo
// https://github.com/torvalds/linux/blob/075dbe9f6e3c21596c5245826a4ee1f1c1676eb8/include/linux/elfcore.h#L73
#define PR_FNAME_LEN 16
if (size < offset + PR_FNAME_LEN) {
return drgn_error_create(DRGN_ERROR_OTHER,
"NT_PRPSINFO is truncated");
}
// No need to make a copy: the data returned by elf_getdata_rawchunk()
// is valid for the lifetime of the Elf handle, and prog->core is valid for
// the lifetime of prog.
const char *tmp = data + offset;
size_t len = strnlen(tmp, PR_FNAME_LEN);
if (len == PR_FNAME_LEN)
#undef PR_FNAME_LEN
return drgn_error_create(DRGN_ERROR_OTHER,
"pr_fname is not null terminated");
*ret = tmp;
return NULL;
}
struct drgn_error *drgn_thread_dup_internal(const struct drgn_thread *thread,
struct drgn_thread *ret)
{
struct drgn_error *err = NULL;
ret->prog = thread->prog;
ret->tid = thread->tid;
/* Don't need a deep copy here since the PRSTATUS notes are cached. */
ret->prstatus = thread->prstatus;
if (thread->prog->flags & DRGN_PROGRAM_IS_LINUX_KERNEL) {
drgn_object_init(&ret->object, thread->prog);
err = drgn_object_copy(&ret->object, &thread->object);
if (err)
drgn_object_deinit(&ret->object);
}
return err;
}
LIBDRGN_PUBLIC struct drgn_error *
drgn_thread_dup(const struct drgn_thread *thread, struct drgn_thread **ret)
{
if (drgn_program_is_userspace_core(thread->prog)) {
/*
* For userspace core dumps, all threads are cached and
* immutable, so we can return the same handle.
*/
*ret = (struct drgn_thread *)thread;
return NULL;
}
*ret = malloc(sizeof(**ret));
if (!*ret)
return &drgn_enomem;
struct drgn_error *err = drgn_thread_dup_internal(thread, *ret);
if (err)
free(*ret);
return err;
}
void drgn_thread_deinit(struct drgn_thread *thread) {
if (thread->prog->flags & DRGN_PROGRAM_IS_LINUX_KERNEL)
drgn_object_deinit(&thread->object);
}
LIBDRGN_PUBLIC void drgn_thread_destroy(struct drgn_thread *thread)
{
if (thread) {
drgn_thread_deinit(thread);
if (!drgn_program_is_userspace_core(thread->prog))
free(thread);
}
}
struct drgn_error *drgn_program_cache_prstatus_entry(struct drgn_program *prog,