static int debuginfo__init_offline_dwarf(struct debuginfo *self,
const char *path)
{
Dwfl_Module *mod;
int fd;
fd = open(path, O_RDONLY);
if (fd < 0)
return fd;
self->dwfl = dwfl_begin(&offline_callbacks);
if (!self->dwfl)
goto error;
mod = dwfl_report_offline(self->dwfl, "", "", fd);
if (!mod)
goto error;
self->dbg = dwfl_module_getdwarf(mod, &self->bias);
if (!self->dbg)
goto error;
return 0;
error:
if (self->dwfl)
dwfl_end(self->dwfl);
else
close(fd);
memset(self, 0, sizeof(*self));
return -ENOENT;
}
/* Get a Dwarf from offline image */
static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
const char *path)
{
int fd;
fd = open(path, O_RDONLY);
if (fd < 0)
return fd;
dbg->dwfl = dwfl_begin(&offline_callbacks);
if (!dbg->dwfl)
goto error;
dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
if (!dbg->mod)
goto error;
dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
if (!dbg->dbg)
goto error;
return 0;
error:
if (dbg->dwfl)
dwfl_end(dbg->dwfl);
else
close(fd);
memset(dbg, 0, sizeof(*dbg));
return -ENOENT;
}
/* Get a Dwarf from live kernel image */
static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
Dwarf_Addr *bias)
{
Dwarf *dbg;
if (!dwflp)
return NULL;
*dwflp = dwfl_begin(&kernel_callbacks);
if (!*dwflp)
return NULL;
/* Load the kernel dwarves: Don't care the result here */
dwfl_linux_kernel_report_kernel(*dwflp);
dwfl_linux_kernel_report_modules(*dwflp);
dbg = dwfl_addrdwarf(*dwflp, addr, bias);
/* Here, check whether we could get a real dwarf */
if (!dbg) {
pr_debug("Failed to find kernel dwarf at %lx\n",
(unsigned long)addr);
dwfl_end(*dwflp);
*dwflp = NULL;
}
return dbg;
}
struct refl *
refl_begin (void)
{
struct refl *result = malloc (sizeof (*result));
if (result == NULL)
{
__refl_seterr (REFL_E_SYSTEM);
return NULL;
}
Dwfl *dwfl = dwfl_begin (&callbacks);
if (dwfl == NULL)
{
__refl_seterr (REFL_E_DWFL);
goto err_out;
}
dwfl_report_begin (dwfl);
int status = dwfl_linux_proc_report (dwfl, getpid ());
dwfl_report_end (dwfl, NULL, NULL);
if (status < 0)
{
__refl_seterr (REFL_E_DWFL);
goto err_out;
}
result->dwfl = dwfl;
return result;
err_out:
free (result);
return NULL;
}
// Create a libdw session with DWARF information for all loaded modules
LibdwSession *libdwInit() {
LibdwSession *session = stgCallocBytes(1, sizeof(LibdwSession),
"libdwInit");
// Initialize ELF library
if (elf_version(EV_CURRENT) == EV_NONE) {
sysErrorBelch("libelf version too old!");
return NULL;
}
// Initialize a libdwfl session
static char *debuginfo_path;
static const Dwfl_Callbacks proc_callbacks =
{
.find_debuginfo = dwfl_standard_find_debuginfo,
.debuginfo_path = &debuginfo_path,
.find_elf = dwfl_linux_proc_find_elf,
};
session->dwfl = dwfl_begin (&proc_callbacks);
if (session->dwfl == NULL) {
sysErrorBelch("dwfl_begin failed: %s", dwfl_errmsg(dwfl_errno()));
free(session);
return NULL;
}
// Report the loaded modules
int ret = dwfl_linux_proc_report(session->dwfl, getpid());
if (ret < 0) {
sysErrorBelch("dwfl_linux_proc_report failed: %s",
dwfl_errmsg(dwfl_errno()));
goto fail;
}
if (dwfl_report_end (session->dwfl, NULL, NULL) != 0) {
sysErrorBelch("dwfl_report_end failed: %s", dwfl_errmsg(dwfl_errno()));
goto fail;
}
pid_t pid = getpid();
if (! dwfl_attach_state(session->dwfl, NULL, pid, &thread_cbs, NULL)) {
sysErrorBelch("dwfl_attach_state failed: %s",
dwfl_errmsg(dwfl_errno()));
goto fail;
}
return session;
fail:
dwfl_end(session->dwfl);
free(session);
return NULL;
}
int
main (void)
{
Dwfl *dwfl = dwfl_begin (&callbacks);
for (int i = 0; i < 5; ++i)
{
dwfl_report_begin (dwfl);
dwfl_report_module (dwfl, "module1", 0, 10);
dwfl_report_end (dwfl, NULL, NULL);
}
dwfl_end (dwfl);
return 0;
}
static Dwfl *
pid_to_dwfl (pid_t pid)
{
static char *debuginfo_path;
static const Dwfl_Callbacks proc_callbacks =
{
.find_debuginfo = dwfl_standard_find_debuginfo,
.debuginfo_path = &debuginfo_path,
.find_elf = dwfl_linux_proc_find_elf,
};
Dwfl *dwfl = dwfl_begin (&proc_callbacks);
if (dwfl == NULL)
error (2, 0, "dwfl_begin: %s", dwfl_errmsg (-1));
report_pid (dwfl, pid);
return dwfl;
}
static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
Dwarf_Addr addr)
{
self->dwfl = dwfl_begin(&kernel_callbacks);
if (!self->dwfl)
return -EINVAL;
dwfl_linux_kernel_report_kernel(self->dwfl);
dwfl_linux_kernel_report_modules(self->dwfl);
self->dbg = dwfl_addrdwarf(self->dwfl, addr, &self->bias);
if (!self->dbg) {
pr_debug("Failed to find kernel dwarf at %lx\n",
(unsigned long)addr);
dwfl_end(self->dwfl);
memset(self, 0, sizeof(*self));
return -ENOENT;
}
return 0;
}
/* Get a Dwarf from live kernel image */
static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
Dwarf_Addr addr)
{
self->dwfl = dwfl_begin(&kernel_callbacks);
if (!self->dwfl)
return -EINVAL;
/* Load the kernel dwarves: Don't care the result here */
dwfl_linux_kernel_report_kernel(self->dwfl);
dwfl_linux_kernel_report_modules(self->dwfl);
self->dbg = dwfl_addrdwarf(self->dwfl, addr, &self->bias);
/* Here, check whether we could get a real dwarf */
if (!self->dbg) {
pr_debug("Failed to find kernel dwarf at %lx\n",
(unsigned long)addr);
dwfl_end(self->dwfl);
memset(self, 0, sizeof(*self));
return -ENOENT;
}
return 0;
}
int main(void)
{
Dwfl *dw;
Dwfl_Module *mod;
Dwarf_Addr bias;
Dwarf_Die *die = NULL;
dw = dwfl_begin(&cb);
if (!dw)
errx(1, "dwfl_begin %s", dwfl_errmsg(-1));
mod = dwfl_report_offline(dw, "", "tst", -1);
if (!mod)
errx(1, "dwfl_begin %s", dwfl_errmsg(-1));
while ((die = dwfl_nextcu(dw, die, &bias))) {
print_die_rec(die, -1);
printf("\n");
}
dwfl_end(dw);
return 0;
}
/* Get a Dwarf from offline image */
static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
{
Dwfl_Module *mod;
Dwarf *dbg = NULL;
if (!dwflp)
return NULL;
*dwflp = dwfl_begin(&offline_callbacks);
if (!*dwflp)
return NULL;
mod = dwfl_report_offline(*dwflp, "", "", fd);
if (!mod)
goto error;
dbg = dwfl_module_getdwarf(mod, bias);
if (!dbg) {
error:
dwfl_end(*dwflp);
*dwflp = NULL;
}
return dbg;
}
struct core_handle *
open_coredump(const char *elf_file, const char *exe_file, char **error_msg)
{
struct core_handle *ch = sr_mallocz(sizeof(*ch));
struct exe_mapping_data *head = NULL, **tail = &head;
/* Initialize libelf, open the file and get its Elf handle. */
if (elf_version(EV_CURRENT) == EV_NONE)
{
set_error_elf("elf_version");
goto fail_free;
}
/* Open input file, and parse it. */
ch->fd = open(elf_file, O_RDONLY);
if (ch->fd < 0)
{
set_error("Unable to open '%s': %s", elf_file, strerror(errno));
goto fail_free;
}
ch->eh = elf_begin(ch->fd, ELF_C_READ_MMAP, NULL);
if (ch->eh == NULL)
{
set_error_elf("elf_begin");
goto fail_close;
}
/* Check that we are working with a coredump. */
GElf_Ehdr ehdr;
if (gelf_getehdr(ch->eh, &ehdr) == NULL || ehdr.e_type != ET_CORE)
{
set_error("File '%s' is not a coredump", elf_file);
goto fail_elf;
}
executable_file = exe_file;
ch->cb.find_elf = find_elf_core;
ch->cb.find_debuginfo = find_debuginfo_none;
ch->cb.section_address = dwfl_offline_section_address;
ch->dwfl = dwfl_begin(&ch->cb);
#if _ELFUTILS_PREREQ(0, 158)
if (dwfl_core_file_report(ch->dwfl, ch->eh, exe_file) == -1)
#else
if (dwfl_core_file_report(ch->dwfl, ch->eh) == -1)
#endif
{
set_error_dwfl("dwfl_core_file_report");
goto fail_dwfl;
}
if (dwfl_report_end(ch->dwfl, NULL, NULL) != 0)
{
set_error_dwfl("dwfl_report_end");
goto fail_dwfl;
}
/* needed so that module filenames are available during unwinding */
ptrdiff_t ret = dwfl_getmodules(ch->dwfl, touch_module, &tail, 0);
if (ret == -1)
{
set_error_dwfl("dwfl_getmodules");
goto fail_dwfl;
}
ch->segments = head;
if (!head)
{
if (error_msg && !*error_msg)
set_error("No segments found in coredump '%s'", elf_file);
goto fail_dwfl;
}
return ch;
fail_dwfl:
dwfl_end(ch->dwfl);
fail_elf:
elf_end(ch->eh);
fail_close:
close(ch->fd);
fail_free:
free(ch);
return NULL;
}
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;
}
/*
* Return:
* 0 if return address for the program counter @pc is on stack
* 1 if return address is in LR and no new stack frame was allocated
* 2 if return address is in LR and a new frame was allocated (but not
* yet used)
* -1 in case of errors
*/
static int check_return_addr(struct dso *dso, u64 map_start, Dwarf_Addr pc)
{
int rc = -1;
Dwfl *dwfl;
Dwfl_Module *mod;
Dwarf_Frame *frame;
int ra_regno;
Dwarf_Addr start = pc;
Dwarf_Addr end = pc;
bool signalp;
const char *exec_file = dso->long_name;
dwfl = dso->dwfl;
if (!dwfl) {
dwfl = dwfl_begin(&offline_callbacks);
if (!dwfl) {
pr_debug("dwfl_begin() failed: %s\n", dwarf_errmsg(-1));
return -1;
}
mod = dwfl_report_elf(dwfl, exec_file, exec_file, -1,
map_start, false);
if (!mod) {
pr_debug("dwfl_report_elf() failed %s\n",
dwarf_errmsg(-1));
/*
* We normally cache the DWARF debug info and never
* call dwfl_end(). But to prevent fd leak, free in
* case of error.
*/
dwfl_end(dwfl);
goto out;
}
dso->dwfl = dwfl;
}
mod = dwfl_addrmodule(dwfl, pc);
if (!mod) {
pr_debug("dwfl_addrmodule() failed, %s\n", dwarf_errmsg(-1));
goto out;
}
/*
* To work with split debug info files (eg: glibc), check both
* .eh_frame and .debug_frame sections of the ELF header.
*/
frame = get_eh_frame(mod, pc);
if (!frame) {
frame = get_dwarf_frame(mod, pc);
if (!frame)
goto out;
}
ra_regno = dwarf_frame_info(frame, &start, &end, &signalp);
if (ra_regno < 0) {
pr_debug("Return address register unavailable: %s\n",
dwarf_errmsg(-1));
goto out;
}
rc = check_return_reg(ra_regno, frame);
out:
return rc;
}