Quelle user.c Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
* Generic interfaces for unwinding user space
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/unwind_user.h>
#include <linux/uaccess.h>

static const struct unwind_user_frame fp_frame = {
ARCH_INIT_USER_FP_FRAME
};

#define for_each_user_frame(state) \
for (unwind_user_start(state); !(state)->done; unwind_user_next(state))

static int unwind_user_next_fp(struct unwind_user_state *state)
{
const struct unwind_user_frame *frame = &fp_frame;
unsigned long cfa, fp, ra;
unsigned int shift;

if (frame->use_fp) {
  if (state->fp < state->sp)
   return -EINVAL;
  cfa = state->fp;
} else {
  cfa = state->sp;
}

/* Get the Canonical Frame Address (CFA) */
cfa += frame->cfa_off;

/* stack going in wrong direction? */
if (cfa <= state->sp)
  return -EINVAL;

/* Make sure that the address is word aligned */
shift = sizeof(long) == 4 ? 2 : 3;
if (cfa & ((1 << shift) - 1))
  return -EINVAL;

/* Find the Return Address (RA) */
if (get_user(ra, (unsigned long *)(cfa + frame->ra_off)))
  return -EINVAL;

if (frame->fp_off && get_user(fp, (unsigned long __user *)(cfa + frame->fp_off)))
  return -EINVAL;

state->ip = ra;
state->sp = cfa;
if (frame->fp_off)
  state->fp = fp;
return 0;
}

static int unwind_user_next(struct unwind_user_state *state)
{
unsigned long iter_mask = state->available_types;
unsigned int bit;

if (state->done)
  return -EINVAL;

for_each_set_bit(bit, &iter_mask, NR_UNWIND_USER_TYPE_BITS) {
  enum unwind_user_type type = BIT(bit);

  state->current_type = type;
  switch (type) {
  case UNWIND_USER_TYPE_FP:
   if (!unwind_user_next_fp(state))
    return 0;
   continue;
  default:
   WARN_ONCE(1, "Undefined unwind bit %d", bit);
   break;
  }
  break;
}

/* No successful unwind method. */
state->current_type = UNWIND_USER_TYPE_NONE;
state->done = true;
return -EINVAL;
}

static int unwind_user_start(struct unwind_user_state *state)
{
struct pt_regs *regs = task_pt_regs(current);

memset(state, 0, sizeof(*state));

if ((current->flags & PF_KTHREAD) || !user_mode(regs)) {
  state->done = true;
  return -EINVAL;
}

if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP))
  state->available_types |= UNWIND_USER_TYPE_FP;

state->ip = instruction_pointer(regs);
state->sp = user_stack_pointer(regs);
state->fp = frame_pointer(regs);

return 0;
}

int unwind_user(struct unwind_stacktrace *trace, unsigned int max_entries)
{
struct unwind_user_state state;

trace->nr = 0;

if (!max_entries)
  return -EINVAL;

if (current->flags & PF_KTHREAD)
  return 0;

for_each_user_frame(&state) {
  trace->entries[trace->nr++] = state.ip;
  if (trace->nr >= max_entries)
   break;
}

return 0;
}

quality98%

¤ Dauer der Verarbeitung: 0.11 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.