#include <dwarf.h>

#include <elfutils/libdwfl.h>

#include "formats-util.h"

#include "macro.h"

#include "string-util.h"

#include "util.h"

#include "stacktrace.h"

#define FRAMES_MAX 64

#define THREADS_MAX 64

struct stack_context {

FILE *f;

Dwfl *dwfl;

Elf *elf;

unsigned n_thread;

unsigned n_frame;

};

static int frame_callback(Dwfl_Frame *frame, void *userdata) {

struct stack_context *c = userdata;

Dwarf_Addr pc, pc_adjusted, bias = 0;

_cleanup_free_ Dwarf_Die *scopes = NULL;

const char *fname = NULL, *symbol = NULL;

Dwfl_Module *module;

bool is_activation;

assert(frame);

assert(c);

if (c->n_frame >= FRAMES_MAX)

return DWARF_CB_ABORT;

if (!dwfl_frame_pc(frame, &pc, &is_activation))

return DWARF_CB_ABORT;

pc_adjusted = pc - (is_activation ? 0 : 1);

module = dwfl_addrmodule(c->dwfl, pc_adjusted);

if (module) {

Dwarf_Die *s, *cudie;

int n;

cudie = dwfl_module_addrdie(module, pc_adjusted, &bias);

if (cudie) {

n = dwarf_getscopes(cudie, pc_adjusted - bias, &scopes);

for (s = scopes; s < scopes + n; s++) {

if (IN_SET(dwarf_tag(s), DW_TAG_subprogram, DW_TAG_inlined_subroutine, DW_TAG_entry_point)) {

Dwarf_Attribute *a, space;

a = dwarf_attr_integrate(s, DW_AT_MIPS_linkage_name, &space);

if (!a)

a = dwarf_attr_integrate(s, DW_AT_linkage_name, &space);

if (a)

symbol = dwarf_formstring(a);

if (!symbol)

symbol = dwarf_diename(s);

if (symbol)

break;

}

}

}

if (!symbol)

symbol = dwfl_module_addrname(module, pc_adjusted);

fname = dwfl_module_info(module, NULL, NULL, NULL, NULL, NULL, NULL, NULL);

}

fprintf(c->f, "#%-2u 0x%016" PRIx64 " %s (%s)\n", c->n_frame, (uint64_t) pc, strna(symbol), strna(fname));

c->n_frame ++;

return DWARF_CB_OK;

}

static int thread_callback(Dwfl_Thread *thread, void *userdata) {

struct stack_context *c = userdata;

pid_t tid;

assert(thread);

assert(c);

if (c->n_thread >= THREADS_MAX)

return DWARF_CB_ABORT;

if (c->n_thread != 0)

fputc('\n', c->f);

c->n_frame = 0;

tid = dwfl_thread_tid(thread);

fprintf(c->f, "Stack trace of thread " PID_FMT ":\n", tid);

if (dwfl_thread_getframes(thread, frame_callback, c) < 0)

return DWARF_CB_ABORT;

c->n_thread ++;

return DWARF_CB_OK;

}

int coredump_make_stack_trace(int fd, const char *executable, char **ret) {

static const Dwfl_Callbacks callbacks = {

.find_elf = dwfl_build_id_find_elf,

.find_debuginfo = dwfl_standard_find_debuginfo,

};

struct stack_context c = {};

char *buf = NULL;

size_t sz = 0;

int r;

assert(fd >= 0);

assert(ret);

if (lseek(fd, 0, SEEK_SET) == (off_t) -1)

return -errno;

c.f = open_memstream(&buf, &sz);

if (!c.f)

return -ENOMEM;

elf_version(EV_CURRENT);

c.elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);

if (!c.elf) {

r = -EINVAL;

goto finish;

}

c.dwfl = dwfl_begin(&callbacks);

if (!c.dwfl) {

r = -EINVAL;

goto finish;

}

if (dwfl_core_file_report(c.dwfl, c.elf, executable) < 0) {

r = -EINVAL;

goto finish;

}

if (dwfl_report_end(c.dwfl, NULL, NULL) != 0) {

r = -EINVAL;

goto finish;

}

if (dwfl_core_file_attach(c.dwfl, c.elf) < 0) {

r = -EINVAL;

goto finish;

}

if (dwfl_getthreads(c.dwfl, thread_callback, &c) < 0) {

r = -EINVAL;

goto finish;

}

c.f = safe_fclose(c.f);

*ret = buf;

buf = NULL;

r = 0;

finish:

if (c.dwfl)

dwfl_end(c.dwfl);

if (c.elf)

elf_end(c.elf);

safe_fclose(c.f);

free(buf);

return r;

}